On Fri, 31 Oct 1997, David S. Wexler, Ph.D. wrote:
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } Hi, } } I have a question about the importance of cover slip thickness. Namely, } how important is it to use a cover slip thickness for which the } objective } is designed? For example, if I'm using a 40X, NA 1.3 oil immersion } objective which has the number 0.17 on it (corrected for a 170 micron } cover slip thickness), what would be the effect on image quality if I } used a cover slip with, say, a 300 micron thickness?
It is important. You are using a precision optical instrument and the cover slip is an indespensible part of the optical correction. Since you are using an oil immersion objective at 40 X (with oil I hope) it appears you want as much defined and clear detail as posible. Using any lense above about 40 X you can see the difference between #1 cover slips (0.13 to 0.17mm thick), #1 1/2 coverslips (0.16 to 0.19mm thick), and #2 cover slips (0.17 to 0.25mm thick). Now having said that, there is an assumption implicit in that. That is that the sample adhears directely to the underside of the coverslip. So don't "flood" with mounting medium.
As an asside, I know one microscopist who measures his coverslips with a micrometer and only uses the ones which are actually 0.17mm.
} Also, what is the definition of "working distance?" I understand it to } be the distance between the top of the cover slip and the lens of the } objective, but I want confirmation of this definition.
You are basically correct.... to be a "sticler" it is the nearest part of the lense, not any optical center of it.
} } Thank you very much, } } Brian Haab } U.C. Berkeley } bhaab-at-zinc.cchem.berkeley.edu }
Good luck,
Shalom from Jerusalem, Azriel
******************************************************** Azriel Gorski, Head azrielg-at-cc.huji.ac.il Optical Microscopy Laboratory Division of Identification and Forensic Science Israel National Police Jerusalem ISRAEL
Dear James, Most microscopists have white, nylon gloves used for handling high vacuum parts, which also cannot tolerate fingerprints. They are comfortable and breathe and do not shed much lint. Try an EM catalogue. You wrote: } } } Here's a new thread. Hand care for microscopists. } } I spend most of each day preparing and analyzing samples using light } microscopy and FT-IR microscopy. Fingerprints are more than a nuisance, } so its frequent trips to the sink for a little soap and water. In the } winter I find my fingertips become dry and cracked. Lotion is out during } work hours. Cotton gloves shed linters. Finger cots provide some relief. } } Anybody have other suggestions? } } James "Fingers" Martin :) } Williamstown Art Conservation Center } Regards, Mary
With all due respect to the members of this Listserver, I do feel compelled to provide additional insight into plasma processing and its related effects on TEM specimens. This response is largely due to Dr. Nestor Zaluzec's recent posting.
Both previous and recent experimentation clearly indicates effective cleaning times for TEM specimens of as little as 15 seconds. This factor is highly dependent on the type of plasma system used, since all plasma types are not equivalent. For those of you that are interested, I would suggest that you reference a book written by Michael A. Lieberman and Allan J. Lichtenberg entitled "Principles of Plasma Discharges and Materials Processing". It provides a great deal of insight into the various types of plasma and their applications.
Regarding the gas type and concentration, we have conducted quantitative measurements of contamination rates using Parallel Electron Energy Loss Spectrometry which indicates equivalent performance of a one minute processing time using a 25% oxygen 75% argon mixture, to a 5 minute cleaning with argon followed by a 5 minute cleaning with 100% oxygen.
When one considers input power into the plasma, whether it is DC or high frequency (HF), other factors such as chamber size and configuration, gas type, plasma processing chamber pressure, electrode style and placement, and Faraday shielding also provide significant contributions to the plasma physics (ion energy, plasma potential, plasma density, electron temperature, and floating potential).
In an non-equilibrium, inductively coupled plasma, increasing the high frequency input power actually decreases the ion energy, which is the most critical parameter for optimal plasma processing. When the proper execution of plasma formation occurs, ion energies of {20 eV are achieved which results in negligible specimen heating and no sputtering effects either from or onto the specimen. On the reverse side, both sputtering and oxygen ion implantation are very real possibilities when the ion energies become excessive.
When considering the safety issues associated with pure oxygen, let us not forget the utilization of pressure regulators certified for oxygen usage, and the avoidance of oils in the pressurized portion of the system.
To conclude, I would be happy to discuss both any data that we have obtained to date, and anyone's issues related to the plasma processing of EM specimens. At this juncture, I do believe that it would be most appropriate to conduct these activities off the Listserver by contacting me directly as follows.
Thank you for your consideration.
Best regards,
Paul
Paul E. Fischione, President E.A. Fischione Instruments, Inc. 9003 Corporate Circle Export, PA 15632 Phone 412-325-5444 FAX 412-325-5443 paul.fischione-at-internetmci.com www.fischione.com
We have GW Electronics chamber cameras on Hitachi and Jeol SEM's. They work great. Just remember to turn the LED illumination off for doing EDX work, as they affect the EDX detector.
We seek information on atomic force microscopes for a future purchase.
Specifically information from:
(a) vendors: models available, capabilities and specs, housing requirements, pricing, references of users, etc.
(b) individual users: models to avoid, positive experiences with a particular model, maintenance, software available, etc.
I shall compile this information for others who may have similar interests. Thank you.
#################################################################### John J. Bozzola, Ph.D., Director Center for Electron Microscopy Neckers Building, Room 146 - B Wing Southern Illinois University Carbondale, IL 62901 U.S.A. Phone: 618-453-3730 Fax: 618-453-2665 Email: bozzola-at-siu.edu Web: http://www.siu.edu/departments/shops/cem.html ####################################################################
Does anyone have suggestions concerning how to prepare a sample of paper laminated with Latex and Saran for examination by SEM/EDX, optical microscopy and micro FTIR. Ideally I would like to observe the sample in cross section with a surface similar in quality to those we prepare by metallographic techniques. Simply cutting by razor smears the surface. The sample was still ductile while submerged in LN2 so we could not obtain a fracture surface. We have had some success cutting with razor while under LN2 but there are still signs of smearing. We could microtome under LN2. Does anyone have other suggestions concerning sample preparation? Are metallographic techniques (embed, grind and polish) feasible? The embedding material must not affect the sample.
Thanks in advance,
Ed Kurz Institute of Materials Science, U-136 University of Connecticut 97 North Eagleville Road Storrs, CT 06269-3136 ekurz-at-mail.ims.uconn.edu (860) 486-4186 phone (860) 486-4745 fax
I think the positioning of the camera depends on the reason you have for using the camera. I have mine looking parallel to the axis of stage tilt, just below the bottom of the pole piece. I can see the gap between my sample and the pole piece as I raise and tilt the sample. I can also see the proximity of the various detectors to the sample. This saves on destroyed samples and detectors!
A young student working in my lab want to study some liposomes using negativ staining. So far with no luck. So if someone out there could help, we would be most grateful. Up til now she has used 2 %PTA pH 7.6 on formvar film coated with carbon. A suspension of liposomes is added on top of the grid, excess liquid removed followed by PTA. We have so far seen only the biggest liposomes, but it seems to be difficult to 'catch' the solicited solution of small particles.
Tips n' tricks would be greatly appreciated.
Best wishes Randi Olsen
Department of Electron Microscopy Faculty of Medicine University of Tromsoe, Norway
Dear all. We are in the lucky situation in my department to have 'spare' money this year, and want to replace our 'old' LKB Tissue Processor who 'died' earlier this fall. It seems like the new RMC or the Lynx machine are the two most current ones. It would be of great help if anyone would share their experiments with us. I'm especially interested in the reliability of the plastic tubes for the processors. We've had lots of problems with the LKB because of lack of accuracy of the plastic ware.
Thanks in advance.
Randi Olsen Department of Electron Microscopy Faculty of Medicine University of Tromso Norway
Hi Randy...we have one of the RMC processors which is about one generation old. Ours allows one to pre-cool (or warm) the solution tube in which your sample will go into next, as well as the current tube. The new machine only controls the temperature of the current tube (which has never made sense to me).
We like our machine and have had few problems. We also had one of the previous machines with the LKB nameplate (they were both made by the same company), and the tubes, with very thin walls, would bend and cause the specimen containing stacking rings to get stuck and left behind. This would raise havoc in the machine, with samples often getting mixed up. The RMC tubes are thicker, and we have not experienced a return of the problem. We are careful to put holes in the caps when the solution tube contains a highly evaporative solvent such as propylene oxide. We found that the vapor pressure would dislodge the caps and cause them to go askew. They would then not be lifted off correctly and would topple into the machine, invariably causing a jam.
Ed Kurz asked: ================================================ Does anyone have suggestions concerning how to prepare a sample of paper laminated with Latex and Saran for examination by SEM/EDX, optical microscopy and micro FTIR. Ideally I would like to observe the sample in cross section with a surface similar in quality to those we prepare by metallographic techniques. Simply cutting by razor smears the surface. The sample was still ductile while submerged in LN2 so we could not obtain a fracture surface. We have had some success cutting with razor while under LN2 but there are still signs of smearing. We could microtome under LN2. Does anyone have other suggestions concerning sample preparation? Are metallographic techniques (embed, grind and polish) feasible? The embedding material must not affect the sample. =================================================== We have been cutting these kinds of samples for some years and have come to the conclusion that there is only one "right" way! I am assuming you have a "paper" substrate, one impregnated with latex and the whole layer is laminated to a layer of "Saran". If the goal is to obtain the "perfect cross-section" then this can be done only via the methods of ultramicrotomy, using cryo techniques, and a diamond knife.
Our step by step procedure would be the following: 1] Sputter coat gold (or preferably Pt but gold is OK) on both sides, the paper side to keep the embedding resin from interacting and possibly dissolving some component in the paper substrate, or even swelling it and the Saran (PVDF) side to act as a superb "decorator" to show the Saran/embedding media interface.
2] We would recommend our own SPI-Pon(TM) 812 Epoxy Embedding Resin but a good number of the other readily available Epon (R) 812 "substitute" materials should work just as well, ones offered by other EM supply firms. Epon Araldite(R) and perhaps other resin systems will "work" too, but the "812" system seems to result in being able to obtain what you want in the shortest possible period of time in terms of learning curve development.
3] Because paper has inorganics in it (e.g. clays, etc.), you surely don't want to use a brand new life science knife to do the cutting. We would recommend saving money and purchasing a materials science diamond knife for this purpose. However, the availability of a beat up life science knife, in need of resharpening, might be quite satisfactory (the quality of the knife edge need not be to the standard as if you were to be looking at the sections, but if the knife is too far gone, you will pick up an intolerable number of defects on the final block you are going to examine.
4] In your case the sections would be thrown out. This brings tears to our eyes since it has been our experience, for these kinds of laminated samples, that the TEM results often times contain much more useful information than the SEM results! But the "faced-off-block" is now the ideal sample for insertion into the SEM (after some metallization or carbon coating).
5] When you look by SEM, you will not have any distortion or interaction of the resin with the sample itself. You might be disappointed in the contrast and to improve it, you might give it a 30 second oxygen plasma etching exposure, so that the gold lines stand up in "relief" better highlighting the location of your sample. If the latex is a polyBD type, then you can expose the sample to osmium tetroxide which could provide additional contrast to the sample, at least in terms of the penetration of the latex.
6] If you have either a "stone" or "fisheye" in either of the layers, if you have successfully cut through the center of the defect, then it will be ideally exposed for EDS, LM, or micro FT/IR analysis. Unlike the case if you were to look at the lateral surface, in this instance, the defect is not being covered up with anything.
This really is a straight forward procedure and has literally "worked" on numerous samples of this and similar types.
Disclaimer: SPI Supplies offers embedding resins, materials science diamond knives, and plasma etchers for doing this kind of work. So we would have a vested interest in the promotion of this kind of approach.
Chuck
=================================================== Charles A. Garber, Ph. D. Ph: 1-(610)-436-5400 President 1-(800)-2424-SPI SPI SUPPLIES FAX: 1-(610)-436-5755 PO BOX 656 e-mail: cgarber-at-2spi.com West Chester, PA 19381-0656 USA Cust. Service: spi2spi-at-2spi.com
Look for us! ############################ WWW: http://www.2spi.com ############################ ==================================================
In a message dated 97-11-03 20:57:11 EST, you write:
{ { Subj: TEM Liposomes. Neg.staining. From: Randio-at-fagmed.uit.no (Randi Olsen)
Dear fellow microscopists.
A young student working in my lab want to study some liposomes using negativ staining. So far with no luck. So if someone out there could help, we would be most grateful. Up til now she has used 2 %PTA pH 7.6 on formvar film coated with carbon. A suspension of liposomes is added on top of the grid, excess liquid removed followed by PTA. We have so far seen only the biggest liposomes, but it seems to be difficult to 'catch' the solicited solution of small particles.
Tips n' tricks would be greatly appreciated.
Best wishes Randi Olsen
Department of Electron Microscopy Faculty of Medicine University of Tromsoe, Norway
} }
I have a couple of suggestions:
1] Apply your suspension to the Formvar surface of the support film rather than the carbon surface. You may 'catch' more of the particles that way.
2] Treat your support films with POLY-L-LYSINE before applying the liposome suspension. To do this use a .01% aqueous solution of POLY-L-LYSINE.
Apply a drop to the carbon surface of the support film and after 5 mins remove excess liquid.
Allow another five minutes for the surface to dry thoroughly (can be speeded up by placing in an oven at 40 degrees centigrade for one minute).
Now apply your suspension and carry out the negative staining as before.
I am finding that the most stubborn material can be examined using this process.
Some time ago I asked for advice on how to tackle our problem with soft resin (see the following e-mail). I received numerous helpful hints and advice which I am very thankful for. One particular advice I was given (by Dr Bronwen Cribb, CMM, UQ) was to replace the alcohol in dehydration series with acetone. Apparently, a small amount of alcohol gets trapped in the block (why??) which causes some blocks to remain soft at the end. The first series of specimens we did with acetone did not show any problem. I thought it was worth sharing this with everybody.
Majid
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Dear All
We are doing TEM on cultured Koala lymphocytes. We are having an on going problem with Spurr's resin (we use medium Spurr's). In some cases resin doesn't get polymerised and stays soft even after 3-4 days in sixty degree oven. The interesting point is that it doesn't happen with every sample. Even in a series of different samples which are processed at the same time and embeded in the same batch of resin, some remain soft while the others are quite Ok.
We heard that some components of culture media may interfere with resin polymerisation so we have been careful to wash the cultured cells properly but it did not eliminate the problem. Any advice on how to tackle the problem is highly appreciated. I would also be thankful if you suggest a way to revive those samples which are embeded in soft resin.
Regards
M. Ghoddusi
Majid Ghoddusi Division of Veterinary Pathobiology The University of Queensalnd QLD 4072 Australia
azriel gorski wrote: } } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } On Fri, 31 Oct 1997, David S. Wexler, Ph.D. wrote: } } } ------------------------------------------------------------------------ } } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } } -----------------------------------------------------------------------. } } } } Hi, } } } } I have a question about the importance of cover slip thickness. Namely, } } how important is it to use a cover slip thickness for which the } } objective } } is designed? For example, if I'm using a 40X, NA 1.3 oil immersion } } objective which has the number 0.17 on it (corrected for a 170 micron } } cover slip thickness), what would be the effect on image quality if I } } used a cover slip with, say, a 300 micron thickness? } } It is important. You are using a precision optical instrument and } the cover slip is an indespensible part of the optical correction. Since } you are using an oil immersion objective at 40 X (with oil I hope) it } appears you want as much defined and clear detail as posible. Using any } lense above about 40 X you can see the difference between #1 cover slips } (0.13 to 0.17mm thick), #1 1/2 coverslips (0.16 to 0.19mm thick), and #2 } cover slips (0.17 to 0.25mm thick). Now having said that, there is an } assumption implicit in that. That is that the sample adhears directely to } the underside of the coverslip. So don't "flood" with mounting medium. } } As an asside, I know one microscopist who measures his coverslips with a } micrometer and only uses the ones which are actually 0.17mm. } } } Also, what is the definition of "working distance?" I understand it to } } be the distance between the top of the cover slip and the lens of the } } objective, but I want confirmation of this definition. } } You are basically correct.... to be a "sticler" it is the nearest part of } the lense, not any optical center of it. } } } } } Thank you very much, } } } } Brian Haab } } U.C. Berkeley } } bhaab-at-zinc.cchem.berkeley.edu } } } } Good luck, } } Shalom from Jerusalem, } Azriel } } ******************************************************** } Azriel Gorski, Head azrielg-at-cc.huji.ac.il } Optical Microscopy Laboratory } Division of Identification and Forensic Science } Israel National Police } Jerusalem } ISRAEL
OK, but wait a minute. Brian also said he is using oil immersion, as well he should be with the lens he described. Oil immersion is sometimes known as "homogeneous immersion" because the optical medium from (and including) the objective front element all the way through to (and including) are of homogeneous optical character. In other words, they are of the same refractive index. The immersion oil is of the same RI as the objective front element, the same as the cover slip, the same as the slide, the same as the condenser front element and (usually) about the same as the mounting medium. Thus, in the special case of oil immersion, it is generally held that the cover slip thickness is irrelevant within reasonable bounds. This is why very often on oil immersion objectives there is no indication of best cover slip thickness. Where cover slip thickness is important is with high numerical aperture _dry_ lenses. The cover slip is always an integral part of the optical system and, as such, its characteristics (including thickness) are incorporated in the calculations of the entire objective lens system. But with high NA lenses there is less tolerance for the aberrations introduced by improper cover slip thickness. Here is an excerpt from the Particle Atlas Electronic Edition (You will note a slight difference in opinion from mine of c.s. thickness with oil immersion):
Chapter 1. Optics and the Microscope Section D. Compound Microscope Subsection 1. Objectives Subsection g. Cover slip thickness
"An important consideration in using different objectives is cover slip thickness. Just how important is the cover slip in the formation of sharp microscopical images? Spinell and Loveland answer this question very completely in a paper entitled "Optics of the Object Space in Microscopy." For the average skilled microscopist, cover slip thickness should be close to the recommended thickness of 0.17 mm (continental and oriental microscopes) or 0.18 mm (U.S. and British microscopes). The allowable variation before detectable image deterioration occurs depends on the numerical aperture of the objective: it is +/- 8 micrometers for a 0.95 NA dry objective; +/-15 micrometers for 0.85 NA; +/-45 micrometers for 0.65; for objectives of NA less than or equal to 0.25 it makes little difference whether a cover slip is used or not. It is also best to use a cover slip of correct thickness for immersion objectives.
"Cover slips vary greatly in thickness and some manufacturers' cover slips are better than those of others. In one test reported by Loveland, a group of Corning No. 1-1/2 cover slips averaged 184 micrometers in thickness and about half of the slips were suitable for use with the 0.95 NA dry objective; nearly 95% were suitable with a 0.85 NA objective (assuming that the objectives are corrected for use with 0.18 mm cover slips). It is best to buy No. 1-1/2 cover slips and to micrometer them when doing critical work."
(The cited Spinel and Loveland paper will be found at J. Roy. Micros. Soc., 79:59-80, 1960.)
By the way, IMHO, Brian's question well illustrates why it is deplorable that in modern universities there is usually no place for a student to learn the fundamentals of light microscopy. Maybe now that you can actually spend $100K on a light microscope, and now that confocal and other "modern" techniques are being used in genetic and other intensely popular research areas, science may once again begin to take the light microscope seriously. Perish the thought, but could we actually see some thought being given to serious instruction on how to use the instrument? There's a radical notion!
(Sorry, its late at night and I'm tired and grumpy. :-p No fault of yours Brian. How could you know better when you've nowhere to turn for education on the subject.)
--
Stephen A. Shaffer MicroDataware sshaffer-at-microdataware.com (business) http://www.microdataware.com (temporarily out of service) steve_shaffer-at-compuserve.com (personal) http://ourworld.compuserve.com/homepages/steve_shaffer/
1. Procedure: I float my grids on top of a drop of solution on Parafilm in a wet chamber for 10-15 min., then pick the grid and blot out the excess solution with Whatman 1 filter. I transfer on the stain solution for 30 sec., blot and dry. In my hands this works better than the other way (solution on grid) which seems to favor uneven spread of the material. 2. Dilution of the liposome solution: find the right dilution which will allow sufficient dispersion of the material on the grid. With a diluted solution you may have to search a little more but there is a far better chance to see the full range of sizes present in your sample. This should prevent the big guys to mask the little ones. 3. Stains: I have used both UAc 2% / trehalose 1% in ddH2O or PTA 2% / trehalose 1% in ddH2O (according to J. Robin Harris) with some success.
I hope this helps. Best regards, Michel
**************************************************** Michel Deschuyteneer, Ph.D. deschuyt-at-sbbio.be Scientist Electron Microscopy Laboratory
SmithKline Beecham Biologicals Rue de l'Institut, 89 B1330 Rixensart, BELGIUM Tel: +32-2-656 9290 Fax: +32-2-656 8164 **************************************************** Standard disclaimer: the opinions expressed in this communication are my own and do not necessarily reflect those of SmithKline Beecham. ****************************************************
Dear all Just my view. I have been using Pegasus mail. The latest version is very versatile and free. Have two different options in the filtering which will look at closed and open folders, with option for including and excluding certain mail if certain key words appear in either the text, heading or subject field. I am a mere happy user. } } } } Has anyone figured out how to segregate from other mail the e-mail } } originating in this forum? } } } } I use Internet Mail & News (v4.70) bundled with Microsoft IE 3.02. The } } "Inbox Assistant" in "Mail" menu is meant to assist in automatic } } segregation to sub-folders, but I have been unable to make it work with } } stuff from the MSA list server. } } } } Any thoughts, suggestions, or recommendations for mail browsers better able } } to do the job? } }
} } } } I use Eudora as my email system, so I don't know if the following will work } with Internet Mail & News. } } In Eudora you can set filters which can look at any part of the message } (header, sender, body, etc.) and take one of several actions (e.g. send to } a specified mailbox). } I have set up a mailbox "microscopy" and a filter which looks in the body } of each incoming message for the prologue which is added by the Microscopy } list server, in particular for the words "Microscopy ListServer". If these } words are found, the message is automatically sent from the "In" mailbox to } the "microscopy" mailbox. } Your system should have an equivalent feature. If not, I suggest you take a } look at Eudora (I have no financial interest in the company, I just like } the product). }
John, the majority of the makers of AFM systems can be found on the Web and they provid a good background to the instruments they sell. Namely ...
Digital Instruments - www.di.com Topometrix - www.topometrix.com Park Scientific (now part of thermospectra) - www.park.com
These are the three main companies, through Burleigh now make a research grade AFM as well as low priced personal AFM and STMs. DME a danish company make the Rasterscope which is a resonably priced machine with mid range capabilities. Recently on the market are Molecular devices and Tools which are a Russian company - i haven't seen their machine in action - but a contact email address for the states is howard-at-ktecintl.com.
As for which machine is the best - I would say that would depend to a degree on you application and the amount of money you wish to spend. Some of the companies' research instruments are for example better for working in liquid than others, others allow for larger samples. I would recomend you get a demonstatration by as many of the manufacturers as you can before making any decision.
Dr. Giles Sanders Laboratory of Biophysics and Surface Analysis School of Pharmacy Nottingham University England
On Mon, 3 Nov 1997 13:37:39 -0500 Ed Kurz {ekurz-at-mail.ims.uconn.edu} wrote:
} Does anyone have suggestions concerning how to prepare a sample of paper } laminated with Latex and Saran for examination by SEM/EDX, optical } microscopy and micro FTIR. Ideally I would like to observe the sample in } cross section with a surface similar in quality to those we prepare by } metallographic techniques. Simply cutting by razor smears the surface. } The sample was still ductile while submerged in LN2 so we could not obtain } a fracture surface. We have had some success cutting with razor while } under LN2 but there are still signs of smearing. We could microtome under } LN2. Does anyone have other suggestions concerning sample preparation? Are } metallographic techniques (embed, grind and polish) feasible? The embedding } material must not affect the sample. } } Thanks in advance, } I've had good results from embedding paper in epoxy resin and polishing, finishing with quarter micron alumina. I also tried LR White, which did not make such good blocks. It doesn't seem to make much difference whether or not you vacuum impregnate.
Regards, Eric ---------------------- Dr Eric E. Lachowski University of Aberdeen Department of Chemistry Meston Walk Old Aberdeen AB24 3UE +44 1224 272934 e.lachowski-at-abdn.ac.uk
We have a problem with our Zeiss DSM 962 which our engineers are, as yet, unable to solve. The turbo pump switches off and an error message indicates that there is "...no 220v supply or the supply line is interrupted". This supply has been checked and found to be normal.
The problem was initially intermittent, occurring immediately or several minutes after the instrument was switched on from cold. It also occurred occasionally after chamber evacuation. However, recently the problem has become so bad that the error message does not respond to the reset button and will only clear when the microscope is switched off at the rear.
The engineers at LEO suspect a fault on the circuit board relating to the vacuum system. I would be interested to hear directly from anyone who has had a similar experience or who might offer advice.
At 07:56 4/11/97 GMT0BST, Giles Sanders wrote: } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America
Also JEOL has a long experience with AFM and STM. Please contact your local sales office.
You can find us on our webside : http://www.jeol.co.jp or http://www.jeol.com
You might try floating the grid on a drop of the suspension on a piece of Parafilm or other hydrophobic surface. You can also try adding a wetting agent like Bacitracin. Or you could charge the surface of the grid with polylyine if the liposomes are negatively charged. I have always used 1-2% uranyl acetate for neg. staining of liposome. Maybe the suspension needs to be diluted as well.
It is possible that you only have large ones in your suspension despite assurances from whoever made them that they should be small. Have they been sized by light scattering or some other method?
Greg Erdos
At 11:57 PM 11/3/97 +0100, you wrote: } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America Scientific Director, ICBR Electron Microscopy Core Lab PO Box 118525 Fax: 352-846-0251 University of Florida E-mail: gwe-at-biotech.ufl.edu Gainesville, FL 32611 http://www.biotech.ufl.edu/~emcl/ Home of the #1 Gators ***** "Many shall run to and fro, and knowledge shall be increased" Daniel 12:4
For current users of automated tissue processors: I would be very interested to know processing protocols and any special resin formulation that is particularly suited for the processor. TIA
Walt Bobrowski Parke-Davis Research bobroww-at-aa.wl.com
} } Has anyone figured out how to segregate from other mail the e-mail } } originating in this forum? } } } } I use Internet Mail & News (v4.70) bundled with Microsoft IE 3.02. The } } "Inbox Assistant" in "Mail" menu is meant to assist in automatic } } segregation to sub-folders, but I have been unable to make it work with } } stuff from the MSA list server. } } } } Any thoughts, suggestions, or recommendations for mail browsers better able } } to do the job? } }
Sorry to post this to the list. But I did not read the original e-mail and the subsequent reply doesn't include the information to allow me to reply to the originator personally.
I use Microsoft IE 3.02 and the Internet Mail and News(v4.70) too. I have been able to segregate most of the MSA mailings using the Inbox assistant. You do need to use more than one instruction to take care of most of the possiblities. I use the following, which seems to filter over 95% of MSA messages into my "MICROSCOPY" box
Move to "MICROSCOPY" if "TO" contains Microscopy-at-Sparc5.microscopy.com Move to "MICROSCOPY" if CC contains Microscopy-at-Sparc5.microscopy.com Move to "MICROSCOPY" if "TO" contains Microscopy and Listserver
I get an occasional rogue MSA message that does not conform to the above but they are rare. It might be worth a try before going to the trouble of changing over your e-mail browser.
The Oklahoma Microscopy Society (OMS) will be holding its fall technical meeting in conjunction with the Oklahoma Academy of Science (OAS) at the University of Arts and Sciences of Oklahoma in Chickasaw, Oklahoma on Friday, November 7, 1997. Any and all are welcome to attend.
Key note speakers for this meeting include: (1) Dr. Biao Ding (Department of Botany, Oklahoma State University, Stillwater, OK) speaking on "Elucidating Intercellular Communications in Plants: Role of Microscopy" and (2) Dr. Robert Nordquist (Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK) speaking on "The Ultrastructure of Laser/Tissue Interactions and Clinical Applications".
Other points of business:
-OMS will be celebrating its 20th Anniversary at the meeting.
-Students will be competing for the annual Timpano Award which is an all expense paid trip to the national MSA meeting the following year.
-Items regarding the upcoming joint spring meeting with the Texas Society will be discussed.
Any questions, please contact Ginger Baker (Secretary/Treasurer) at (918) 561-8232 or Phoebe Doss (President) at (405) 744-6765.
The Oklahoma Microscopy Society (OMS) will be holding its fall technical meeting in conjunction with the Oklahoma Academy of Science (OAS) at the University of Arts and Sciences of Oklahoma in Chickasaw, Oklahoma on Friday, November 7, 1997. Any and all are welcome to attend.
Key note speakers for this meeting include: (1) Dr. Biao Ding (Department of Botany, Oklahoma State University, Stillwater, OK) speaking on "Elucidating Intercellular Communications in Plants: Role of Microscopy" and (2) Dr. Robert Nordquist (Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK) speaking on "The Ultrastructure of Laser/Tissue Interactions and Clinical Applications".
Other points of business:
-OMS will be celebrating its 20th Anniversary at the meeting.
-Students will be competing for the annual Timpano Award which is an all expense paid trip to the national MSA meeting the following year.
-Items regarding the upcoming joint spring meeting with the Texas Society will be discussed.
Any questions, please contact Ginger Baker (Secretary/Treasurer) at (918) 561-8232 or Phoebe Doss (President) at (405) 744-6765.
I need to prepare TEM specimens of Inconel 718 superalloy . I was going to start with perchloric and ethanol at about - 35 C. I would however appreciate getting "recipes" from people with more experience on this matter.
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Marti, Jordi wrote: } } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } After polishing my sample I immersed it in acetone to dissolve the cement } and after it had separated from the glass support I examined it by OM . } At that point I noticed that a thin solid film of the colloidal, } non-crystallizing silica, had formed on the surface of the sample. Is there } a safe way of removing this film ?? I've tried soaking the sample in the } colloidal suspension and in water but it did no seem to help. } } I suspect the film formed because I failed to wash the sample properly } before putting it in the acetone but I hate the idea of starting all over } again. } } I would appreciate any suggestions. } } Jordi Marti Dear Jordi,
Our Micro Organic Soap is used to remove our Non-Crystallizing Colloidal Silica Suspension in both 0.05 and 0.02 micron sizes. Either dilute it in water or use it full strength. The part number is 148-10000 and sells for 10 dollars a quart.
I have also heard Methanol works sometimes.
Good Luck,
Gary Liechty Product Application Specialist
Allied High Tech Products, Inc. 2376 E. Pacifica Pl. Rancho Dominguez, Ca. 90220 800-675-1118 310-635-2466 310-762-6808 Fax www.AlliedHighTech.com
Products for Materiallographic, SEM and TEM Sample Preparation
So how do you tell if you have spherical aberration due to cover glass thickness? You look at a tiny particle as you go in and out of focus. Spherical aberration will give you a small white spot in the center when you are out of focus one way, and not the other. Also the diffraction pattern around the particle will be different on one side of focus than the other--it is not symmetric in out-of-focus direction.
best regards mark
Mark W. Lund, PhD Director } } Soft X-ray Web page http://www.moxtek.com { { MOXTEK, Inc. 452 West 1260 North Orem UT 84057 801-225-0930 FAX 801-221-1121 lundm-at-xray.byu.edu
"The state is good at simple tasks, like killing people and seizing their wealth. It has far more trouble reaching inside individuals and making them good." Doug Bandow
A user in our lab wishes to image radiolarians (nearly pure SiO2) and separate them from the matrix (smectite to illite clay) in order to do an analysis of area/volume ratios.
In fractured samples we can see the radiolarians easily in the SEM, but he wants to be able to do image analysis on a picture and pick out the rads by doing some thresholding. In our pictures, the rads and the matrix are all similar in gray value.
Whole rads are 60 - 80 um in diameter, but they are also found as 'chunks' as small as 3 um. The clay particles of the matrix are from 1 - 5 um in size. He wants to separate even small particles of rads to get a measure of displacement and volume changes. I suggested that he may have to prepare a polished surface to examine, but he would like to avoid doing that since the samples are somewhat friable and he is not sure how to proceed.
We tried SEI and BSE imaging in the SEM, but the gray values are too close to do much thresholding. We tried doing some x-ray mapping, but Si is abundant in both the rads and the matrix so not much to go on there. Any elements unique to either the rads or the matrix seem to be present in concentrations too low to make a good separation using x-ray maps.
I have told him that I think this is a hard problem, but that I would send a message to the list to see if anyone had any ideas or leads on techniques. So, what do you think?
Jonathan Krupp Microscopy and Imaging Lab University of California Santa Cruz, CA 95064 (408) 459-2477 FAX (408) 429-0146 jmkrupp-at-cats.ucsc.edu
I would like to hear from anyone who has experience in the staining of poly(4-vinyl pyridine). The material in question is a copolymer diblock of poly(styrene-b-4-VP). If anyone out there can offer assistance I'd appreciate hearing from you. Thanks.
Paul Gerroir Xerox Research Centre of Canada Subscibe Microscopy Paul_Gerroir-at-xn.xerox,com
Good question: Not readily, I'm afraid. It is actually difficult to assess whether liposomes are uni- or multi-lamellar with neg staining. Actually, the best method to answer this is cryo-EM of a frozen hydrated suspension of the liposomes.
Regards, Michel
At 18:21 4/11/97 +0100, you wrote: } } Michel, } } I wonder how readily do you get to see if your liposomes are } multilamellar or not? } } Manoj } } Dr. Manoj MISRA, } Unilever Research } 45 River Road } Edgewater, NJ 07020 } (201)840-2702 (voice) } (201)840-8299 (fax) } Manoj.Misra-at-unilever.com } **************************************************** Michel Deschuyteneer, Ph.D. deschuyt-at-sbbio.be Scientist Electron Microscopy Laboratory
SmithKline Beecham Biologicals Rue de l'Institut, 89 B1330 Rixensart, BELGIUM Tel: +32-2-656 9290 Fax: +32-2-656 8164 **************************************************** Standard disclaimer: the opinions expressed in this communication are my own and do not necessarily reflect those of SmithKline Beecham. ****************************************************
I was asked recently if it is possible to get a final image on a Zeiss 902 that shows signs of astigmatism just in one half of the negative, the other half appears to be OK. Could this situation occur in a microscope that is OK due to misalignment of the energy filtering system by the user, or is this definitely a hardware problem?
Thank you for your help, Stefan
Dr. Stefan Hillmer Albrecht-von-Haller Institut fuer Pflanzenwissenschaften Universitaet Goettingen Untere Karspuele 2 37073 Goettingen Deutschland
Tel (+49) 551-392013 Fax (+49) 551-397833 e-mail shillme-at-gwdg.de
At 06:25 PM 11/4/97 -0600, Bob Wise wrote: } I'm considering buying some rebuilt SEM filaments (W). I am seeking input } from users as to how they compare to new (manufacturers or second source).
This issue comes up from time to time. Energy Beam Sciences has been manufacturing new and rebuilt tungsten filaments for EMs for more than 25 years, and I am regularly asked this question. I can't speak for other manufacturers, but I can state categorically that *our* rebuilt filaments are functionally identical to *our* new filaments. The bases are cleaned, identical filament loops are welded to the posts, and the finished filaments are aligned, vacuum annealed, then checked again for alignment. In blind tests, there was no variation at all between the performance of new and rebuilt filaments in the same microscope.
That being said, there may well be differences in *design* between filaments sold by the column manufacturer and rebuilt filaments manufactured by a third party. These differences can very well influence filament performance, both positively and negatively. If I were considering the use of rebuilt filaments, I would ask the manufacturer if the loop configuration differs from the filaments sold by the EM manufacturer and, if so, why.
Best regards, Steven E. Slap, Vice-President ******************************** Energy Beam Sciences, Inc. Adding Brilliance To Your Vision ebs-at-ebsciences.com http://www.ebsciences.com/ ********************************
Further to the "Dry hands" thread I've seen lately, I think there's a general humidity problem in a lot of labs, at least in colder climates where the central heating is on all winter. In my own lab, in a large building built in the late '70s, the humidity can get down to 15 - 20% by February or early March. This is probably a good environment for, say, preserving Lenin's corpse, but is not generally appropriate for living non-communist microscopists. I don't work with a lot of chemicals or irritants of any kind (except the Admin people), so when my hands get dry and chapped, I think it's just because of the dessicating environment. I'm thinking of installing a humidifier in the lab here, at least for winter use. Has anyone out there been able to successfully regulate a comfortable humidity level in a cool-climate lab? I'm going to have to be careful about approaching management to pay for a humidifier, though, because our building is just now going through some major renovation to take care of a minor outbreak of Stachybotras (a damp-loving mold that can be quite toxic to some people) that occurred in another, much moister part of the complex. So when they hear anything about me wanting to increase a humidity level somewhere, they may get a little squirrely on me.
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Dear Manoj,
It is well documented in literature that negative staining deteriorates the original structure of liposomes. The technique should not be used for their observation!!!!!!.
I always perform the LT observation in TEM of vitrified thin films in parallel with freeze fracture. Discrimination between uni- and multi-lamellar in thin films is straight forward. The freeze fracture in parallel is to have a confirmation of your findings in thin film. The thin film preparation can introduce various artefacts, e.g.: 1 selection of diameter size ( Determined by the film thickness the liposomes are ordered in their diameter. Diameters larger than the thickness of the film are excluded from the thin film and will not be visible in the TEM. 2.in case of viscous liquids, mechanical stresses are applied during thin film preparation, which can cause phase inversion. 3.Diameter sizes larger than the film thickness present in the film can be deformed and have lost their spherical shape (have become flattened between both air/water interfaces of the film. Tilting of the grid in the beam is needed to check on the shape of the vesicles. In the freeze fracture replica all sizes are present in their actual shape and distribution in the dispersion. Replication is limited in discrimination between uni- and multi-lamellar vesicles. Insight in this aspect is only obtained in case of cross-fractures through vesicles.
------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America
Hi Manoj.
Good question: Not readily, I'm afraid. It is actually difficult to assess whether liposomes are uni- or multi-lamellar with neg staining. Actually, the best method to answer this is cryo-EM of a frozen hydrated suspension of the liposomes.
Regards, Michel
At 18:21 4/11/97 +0100, you wrote: } } Michel, } } I wonder how readily do you get to see if your liposomes are } multilamellar or not? } } Manoj } } Dr. Manoj MISRA, } Unilever Research } 45 River Road } Edgewater, NJ 07020 } (201)840-2702 (voice) } (201)840-8299 (fax) } Manoj.Misra-at-unilever.com } **************************************************** Michel Deschuyteneer, Ph.D. deschuyt-at-sbbio.be Scientist Electron Microscopy Laboratory
SmithKline Beecham Biologicals Rue de l'Institut, 89 B1330 Rixensart, BELGIUM Tel: +32-2-656 9290 Fax: +32-2-656 8164 **************************************************** Standard disclaimer: the opinions expressed in this communication are my own and do not necessarily reflect those of SmithKline Beecham. ****************************************************
PHILADELPHIA SOCIETY FOR MICROSCOPY MEETING NOTICE: Wednesday Night, NOVEMBER 12, 1997
RESOLVING CHEMISTRY WITH INFRARED MICROSPECTROSCOPY
John A. Reffner, Ph.D., Spectra-Tech, Inc. 2 Research Drive, Shelton, CT 06484 --------------------- Members and Non-Members Welcome - Location and Reservation Information at end of this note. Reservation deadline Friday at 12:00.
Newsletter is also available at: http://www.msa.microscopy.com/~psmlas/newsltrs.html ------------------
Abstract
Infrared microspectrometry (IMS) is the measurement of infrared spectra through a microscope coupled to Fourier transform spectrometer. This FT-IR microscope is a tool used to visually detect microscopically small samples or domains and to record their infrared spectra. This instrumentation unites two sciences, microscopy and spectroscopy. IMS has been applied to analysis of adhesives, cosmetics, copy toners, drugs, explosives, fibers, inks, paints, plastics and soils on a truly ultra-microscopic scale. Samples weighing a few nanograms are routinely identified and quantified. When microscopy and spectroscopy are used together, scientists have a greater discrimination power. Infrared spectroscopy resolves chemistry, while microscopy resolves shape and form. IMS is used identify a single fiber or to differentiate a nylon-6 fiber from nylon-6,6 fiber. Today that is not too impressive but, using IMS to separate single acrylic fibers into 23 unique compositional classes has been a major advance for identification of trace evidence in forensic investigations.
IMS places new demands on the analyst --- you must be both microscopist and spectroscopist. Microscopy has a long and distinguished history of measuring, evaluating and comparing materials. Microscopes lets you see more detail, detect unseen structure and solve problems. Add the ability to get infrared spectra of any microscopic domain and your power expands to resolve molecular chemistry.
Microscopy can be defined as the art and science of creating, recording and interpreting magnified images. The combination of SEM with EDX gave us the ability to do elemental analysis, now the molecular chemistry can be probed using the combination of light microscopy with infrared spectroscopy.
------- Sponsored by: KEVEX manufactures X-ray Analyzers, capable of analyzing sample sizes ranging from microns to millimeters, thickness from angstroms to microns, and elemental concentrations from PPM to weight percents.
--------------------------------------------------- NOVEMBER MEETING DETAILS
Wednesday, November 12, 1997 Location: LRSM Building (Laboratory for Research on the Structure of Matter), UPENN, 33rd and Walnut Street (map enclosed). Parking is available behind the LRSM after 5:00 PM. (We have made arrangements with UPENN, they say they will not tow) Cost of Dinner: Members $12.00, Students $6, Non-Members $15. Schedule: 5:30 Social hour. Hosted by our meeting sponsor. 6:30 Dinner Menu: Steamed Dumplings with Plum Sauce, Fried Wontons Chicken Stir Fry, Vegetarian Stir Fry, Rice Spinach Salad with Fresh Mushrooms and Almonds Fruit, Fortune Cookies, Coffee, Decafe, Tea Reservations: By E-Mail (preferred): Send your name and affiliation to PSM-RESERVATIONS-at-INAME.COM By Phone: Call Ms. Pat Overend at (215) 898-8337. DEADLINE for RESERVATIONS is 5:00 PM Thursday November 6th. Reservations are required. We cannot guarantee you a meal if you do not make a reservation prior to the deadline.
About the Speaker
For the past ten years Dr. Reffner has been employed by Spectra-Tech, first as a Corporate Fellow and for the last three years as Research Director. In this role Dr. Reffner has led the technical development of infrared microspectroscopy. Prior to joining Spectra-Tech, he was a Principal Scientist with American Cyanamide (1977 - 87), Assistant Director of the Institute of Material Sciences at the University of Connecticut (1966 - 77) and Research Director at McCrone Associates, Chicago, Illinois (1958 - 66). His undergraduate education was at Akron University. He received a master's degree at Illinois Institute of Technology and a doctorate from the University of Connecticut. In addition to infrared microspectroscopy include polymer science, microscopy and forensic science. He is a Special Consultant to the Connecticut State Police and is on the editorial board of the Journal of Forensic Science.
-- "Opinions expressed are mine and not those of Rohm and Haas Company"
I need some advice. What would be a good journal to publish a technical advance type of paper which reports a methodological improvement for immunoEM studies of plant tissues ?
Thanks in advance,
Soumitra
Soumitra Ghoshroy Department of Biochemistry and Cell Biology State University of New York at Stony Brook Stony Brook, NY 11794-5215 Tel: 516-632-9536 Fax: 516-632-8575
Do you fix your membranes before negative staining?
We do negative stain our fixed samples, and we get beautiful results, and yes, it is easy for us to see the lamination.
Though we've seen nice results from unfixed samples as well.
We use Amonium Molybdate, at pH 6.3
Lou Ann
} [Marcel Paques:] } It is well documented in literature that negative staining deteriorates the } original structure of liposomes. The technique should not be used for their } observation!!!!!!.
Lou Ann Miller Center for Microscopy & Imaging College of Veterinary Medicine Dept. of Veterinary Biosciences University of Illinois Rm 1108 Basic Sciences Bld 2001 S Lincoln Ave. Urbana, Illinois 61802
For the purposes of equipment replacement, costing for microscopy, as well as other reasons our Admin people have asked me to tell them what the life expectancy of electron microscopes is. We need to know this value because it is an integral part of any calculations we have to do with respect to our microscopes.
I have worked on both TEMs and SEMs that have been close to 25 years old, and still running well enough to allow us to get the information we required. I have also talked with some colleagues who have given 10 years as the expectancy, when the equipment, although it still may be working well, is considered to be "outdated".
In this vein, I would be interested to hear from colleagues and commercial folks alike to see what the general consensus is, and what a reasonable value for life expectancy is. This is important because this is the value I will always use in all my calculations from now on.
Thank you.
Paula Allan-Wojtas Food Microstructure Specialist Agriculture and Agri-Food Canada Atlantic Food and Horticulture Research Centre Kentville, Nova Scotia Canada B4N 1J5
How to tell if liposomes are uni or multi-lamellar ?
Freeze fracture.
Regards
John John Manston Electron Microscope Unit Faculty of Medical Sciences Queen Mary and Westfield College University of London Mile End Road London E1 4NS Tel +171 982 6961 Fax +181 983 0613
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Dear Marcel
Yes I realize that. And we do do freeze fracture and cryo-TEM to see lamellar structures in liposomes. However, we negatively stain liposomal preps prior to freezing to perform preliminary assessment of their quality and density. Often in such collapsed vesicles one gets to see muti-lamellar striations.
It is well documented in literature that negative staining deteriorates the original structure of liposomes. The technique should not be used for their observation!!!!!!.
I always perform the LT observation in TEM of vitrified thin films in parallel with freeze fracture. Discrimination between uni- and multi-lamellar in thin films is straight forward. The freeze fracture in parallel is to have a confirmation of your findings in thin film. The thin film preparation can introduce various artefacts, e.g.: 1 selection of diameter size ( Determined by the film thickness the liposomes are ordered in their diameter. Diameters larger than the thickness of the film
are excluded from the thin film and will not be visible in the TEM. 2.in case of viscous liquids, mechanical stresses are applied during thin film preparation, which can cause phase inversion. 3.Diameter sizes larger than the film thickness present in the film can be deformed and have lost their spherical shape (have become flattened between both air/water interfaces of the film. Tilting of the grid in the beam is needed to check on the shape of the vesicles. In the freeze fracture replica all sizes are present in their actual shape and distribution in the dispersion. Replication is limited in discrimination between uni- and multi-lamellar vesicles. Insight in this aspect is only obtained in case of cross-fractures through vesicles.
------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America
Hi Manoj.
Good question: Not readily, I'm afraid. It is actually difficult to assess whether liposomes are uni- or multi-lamellar with neg staining. Actually, the best method to answer this is cryo-EM of a frozen hydrated suspension of the liposomes.
Regards, Michel
At 18:21 4/11/97 +0100, you wrote: } } Michel, } } I wonder how readily do you get to see if your liposomes are } multilamellar or not? } } Manoj } } Dr. Manoj MISRA, } Unilever Research } 45 River Road } Edgewater, NJ 07020 } (201)840-2702 (voice) } (201)840-8299 (fax) } Manoj.Misra-at-unilever.com } **************************************************** Michel Deschuyteneer, Ph.D. deschuyt-at-sbbio.be Scientist Electron Microscopy Laboratory
SmithKline Beecham Biologicals Rue de l'Institut, 89 B1330 Rixensart, BELGIUM Tel: +32-2-656 9290 Fax: +32-2-656 8164 **************************************************** Standard disclaimer: the opinions expressed in this communication are my own and do not necessarily reflect those of SmithKline Beecham. ****************************************************
Microscopy-at-sparc5.microscopy.com Original-Encoded-Information-Types: IA5-Text X400-Content-Type: P2-1984 Message-ID: {"ISOPRO::DH-EF::1BEA::3460A54A"*/G=Allen/S=White/O=txmta1/PRMD=AMD/ADMD=ATTMAIL/C=US-at-MHS} Importance: normal
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It's been 25 years since I've been in a micropaleontology prep lab but I do remember that rads are quite durable. They would be soaked them for a couple of days in Quaternary-O, I think a petroleum based dispersant. The clay was dispersed in a blender and then the rads filtered out with a 300 or so mesh sieve. I have seen rads removed from well indurated rocks bordering on chert by an overnight soaking in dilute HF followed by siving.
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Hi:
A user in our lab wishes to image radiolarians (nearly pure SiO2) and separate them from the matrix (smectite to illite clay) in order to do an analysis of area/volume ratios.
In fractured samples we can see the radiolarians easily in the SEM, but he wants to be able to do image analysis on a picture and pick out the rads by doing some thresholding. In our pictures, the rads and the matrix are all similar in gray value.
Whole rads are 60 - 80 um in diameter, but they are also found as 'chunks' as small as 3 um. The clay particles of the matrix are from 1 - 5 um in size. He wants to separate even small particles of rads to get a measure of displacement and volume changes. I suggested that he may have to prepare a polished surface to examine, but he would like to avoid doing that since the samples are somewhat friable and he is not sure how to proceed.
We tried SEI and BSE imaging in the SEM, but the gray values are too close to do much thresholding. We tried doing some x-ray mapping, but Si is abundant in both the rads and the matrix so not much to go on there. Any elements unique to either the rads or the matrix seem to be present in concentrations too low to make a good separation using x-ray maps.
I have told him that I think this is a hard problem, but that I would send a message to the list to see if anyone had any ideas or leads on techniques. So, what do you think?
Jonathan Krupp Microscopy and Imaging Lab University of California Santa Cruz, CA 95064 (408) 459-2477 FAX (408) 429-0146 jmkrupp-at-cats.ucsc.edu
Message-Id: {199711051510.JAA24950-at-mailhub.iastate.edu} X-Sender: wes-at-pop.ameslab.gov X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"
What about using the Al in the clay to note the difference? There should be enough.
Certainly doing x-ray maps is not as fast as SEI or BSE imaging, but it can work. We have done it routinely to pick out phases in cement paste for image analysis.
At 04:01 PM 11/4/97 -0800, you wrote: } Hi: } } A user in our lab wishes to image radiolarians (nearly pure SiO2) and } separate them from the matrix (smectite to illite clay) in order to do an } analysis of area/volume ratios. } } In fractured samples we can see the radiolarians easily in the SEM, but he } wants to be able to do image analysis on a picture and pick out the rads by } doing some thresholding. In our pictures, the rads and the matrix are all } similar in gray value. } } Whole rads are 60 - 80 um in diameter, but they are also found as 'chunks' } as small as 3 um. The clay particles of the matrix are from 1 - 5 um in } size. He wants to separate even small particles of rads to get a measure of } displacement and volume changes. I suggested that he may have to prepare a } polished surface to examine, but he would like to avoid doing that since } the samples are somewhat friable and he is not sure how to proceed. } } We tried SEI and BSE imaging in the SEM, but the gray values are too close } to do much thresholding. We tried doing some x-ray mapping, but Si is } abundant in both the rads and the matrix so not much to go on there. Any } elements unique to either the rads or the matrix seem to be present in } concentrations too low to make a good separation using x-ray maps. } } I have told him that I think this is a hard problem, but that I would send } a message to the list to see if anyone had any ideas or leads on } techniques. So, what do you think? } } Jonathan Krupp ---------------------------------------------------- Warren E. Straszheim 23 Town Engineering Iowa State University Ames IA, 50011 Phone: 515-294-8187 FAX: 515-294-8216
Here are my two cents, I would say that: as it's so easy to do cryo EM on liposomes you should never try Neg. Staining. You will just loose your time... And cryoEM give you much more results about the structure of your suspension.
A cryo EMist
------------------------------ SCHMUTZ Marc IGBMC 1 rue Laurent FRIES BP 163 F 67404 Illkirch Cedex FRANCE
Good start. As an iteration on your basic recipe, add more viscosity by using 4 vol% perchloric in equal parts ethanol/methanol/butanol. This can improve the polish, but not always....
David B. Snow Pratt & Whitney Materials & Mechanics Engineering 400 Main St. (MS 114-45) East Hartford, CT 06108 860 565 7823 snowdb-at-pweh.com
Consider the potential dust problem with any but an evaporative humidifer (or used distilled water). Misting units will cause dissolved minerals in the water to precipitate and mineral "snow" will eventually cover everything. Could be a problem in an EM lab.
Woody White, Electron Microscopist SEM/EDS/WDS
Work: Mcdermott Technology, Inc. woody.n.white-at-mcdermott.com http://www.mtiresearch.com/
I'm thinking of installing a humidifier in the lab here, at least for winter use. Has anyone out there been able to successfully regulate a comfortable humidity level in a cool-climate lab? I'm going to have to be careful about approaching management to pay for a humidifier, though, because our building is just now going through some major renovation to take care of a minor outbreak of Stachybotras (a damp-loving mold that can be quite toxic to some people) that occurred in another, much moister part of the complex. So when they hear anything about me wanting to increase a humidity level somewhere, they may get a little squirrely on me.
A fellow student working in our lab is looking for protocols for embedding liposomes in resin. Anyone familiar with protocols other than cryoEM that will work?
Lisa D. Brown University of Connecticut Physiology and Neurobiology Department Electron Microscopy Laboratory Box U-131, Rm 129 Beach Hall Storrs, Ct 06269-2131 Tel. (860)486-2914 Fax. (860)486-1936
We may need a microtome periodically (rm. temp. for now, cryo in the future) while we are performing experiments at Brookhaven National Lab, Upton, NY. We may be in need of the microtome as early as Monday, November 10th. We would have our own supplies, including knives, and our own operator with 15 years microtomy experience. It would need to be within approximately a one hour drive of Brookhaven, readily available and rentable by the hour. If anyone has suggestions please contact me.
Michael T. Dineen The Dow Chemical Company 1897 Building Midland MI 48667 (517/636-4008 4 517/638-6443 + mtdineen-at-dow.com
National Institutes of Health Bethesda, Maryland Laboratory of Structural Biology Research National Institute of Arthritis, Musculoskeletal & Skin Diseases
Technical specialist in support of high resolution macromolecular electron microscopy program (P.I. Dr. Alasdair C. Steven).
Responsibilities involve maintaining/operating/ testing/development of instrumentation (transmission electron microscopes, cryo-holders, freeze-etch machine and cryo-microtome) Experience in and aptitude for these activities is desirable, although some on-the-job training is possible. Also includes responsibilities for management of EM facility. Background in physical or life sciences or bioengineering at BS or MS level plus practical experience. Appointment at GS9 - GS11 level (approx. $31, 680 - $49,831), according to experience.
For further information and detailed instructions about application procedure, please contact :
Ms. Kathy Phelan Bldg. 45, Rm. 5AS53 National Institutes of Health Bethesda, MD 20892 Tel: (301) 435-5315 Fax : (301) 435-5319
wise-at-vaxa.cis.uwosh.edu wrote: } } ------------------------------------------------------------------------} The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------.} } I'm considering buying some rebuilt SEM filaments (W). I am seeking input } from users as to how they compare to new (manufacturers or second source). } } TIA } } Bob } } Dr. Robert R. Wise } Department of Biology } University of Wisconsin-Oshkosh } Oshkosh, WI 54901 } } (920) 424-3404 tel } (920) 424-1101 fax } wise-at-uwosh.edu
Dr. Wise,
Since Ladd Research has been providing both new and rebuilt tungsten filaments for many years we feel we have no bias either way in this matter. For rebuilt filaments we clean the bases, afix the same configyration of tungsten loop as the EM manufacturer and anneal the filament. The life and preformance should be the same for new and rebuilt. We would suggest rebuilt filaments unless the base is contaminated and can not be cleaned. Some of the older scopes use porous ceramic bases which are differcult to clean and should be replaced.
John Arnott Chairman Ladd Research 13 Dorset Lane Williston, VT 05495 tel 1-800-451-3406 fax 1-802-878-8074
I Have sections of fluorescently labelled rat spinal cord and would like to counterstain the entire section to show a general morphological outline that accentuates white/grey matter, etc. The stain can be either fluorescent, or, more likely, visualized with a light microscope. I am having difficulty finding a genral histology stain which is not autofluorescent.
Any suggestions?
Judy Trogadis Eye Research Institute and University of Toronto Toronto Hospital, Western Div. 399 Bathurst St. Toronto, Canada M5T 2S8
Hi Soumitra, You might consider sending your Technical Advance paper to the Journal of Microscopy Research and Technique.
John E. Johnson is the editor and the editorial office address is: 165 Cervantes Road Redwood City, CA 94062 ph: 415-366-1644 FAX: 415-367-9630
cheers ed
Edward J. Basgall, PhD The Pennsylvania State University Surface Chemistry Group ejb11-at-psu.edu Materials Research Institute Building Ph: 814-865-0493 University Park, PA 16802-7003 FAX: 814-863-0618 http://www.personal.psu.edu/ejb11/ Privilege does not absolve one of ecological responsibility.
I have a CL detector attached to my ISI SEM. The detector is not a mirror-type detector. It consists of an acrylic light pipe and a photomultiplier tube. Lately the CL image signals are getting weaker and noisy. I am thinking that the light pipe may get contaminated. How can I clean the detector ? Thanks.
In Posteket al., as well as other SEM texts, it is stated that characteristic x-rays are emitted from a deeper zone in the interaction volume than backscattered electrons. If the depth at which signals are emitted is a function of the energy of that signal, why are the lower energy X-rays (which have energies of ~1kV to ~20 kV at an accelerting voltage of 25 kV) coming from a deeper depth than BSE (which would have energies of ~25 kV)?
Bob
Dr. Robert R. Wise Department of Biology University of Wisconsin-Oshkosh Oshkosh, WI 54901
(920) 424-3404 tel (920) 424-1101 fax wise-at-uwosh.edu
If you are using FITC, I have had good success couterstaining with .01% Evans Blue. It is fluorescent with texas red filter set and works great as a total counterstain with tissue labelled with FITC.
Bob
On Wed, 5 Nov 1997, Judy Trogadis wrote:
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } I Have sections of fluorescently labelled rat spinal cord and would like to } counterstain the entire section to show a general morphological outline } that accentuates white/grey matter, etc. The stain can be either fluorescent, } or, more likely, visualized with a light microscope. I am having difficulty } finding a genral histology stain which is not autofluorescent. } } Any suggestions? } } Judy Trogadis } Eye Research Institute and } University of Toronto } Toronto Hospital, Western Div. } 399 Bathurst St. } Toronto, Canada M5T 2S8 } } phone: 416-603-5088 } Fax: 416-603-5126 } email: judy-at-playfair.utoronto.ca } } }
Bob Wise wrote: } } I'm considering buying some rebuilt SEM filaments (W). I am seeking input } from users as to how they compare to new (manufacturers or second source). } ------------------------------------------------------------------------------- } -----------------------------
I've bought reconditioned filaments for several years and I have not noticed any differences compared to new filaments. Occasionally I have bought new filaments from a "second source".
Russell E. Cook Scientific Associate Electron Microscopy Center for Materials Research Argonne National Laboratory Building 212 9700 South Cass Avenue Argonne, IL 60439 (630)252-7194 FAX: (630)252-4798
Anybody out there know how to contact a Balzar's rep in the US. I am interested in getting info on their high pressure freezer.
Thomas E. Phillips, Ph.D. Associate Professor of Biological Sciences Director, Molecular Cytology Core Facility 3 Tucker Hall University of Missouri Columbia, MO 65211 (573)-882-4712 (voice) (573)-882-0123 (fax)
Kindly instruct me on how to be removed from this list. I have tried sending unsubscribe messages 3 times to ListServer-at-MSA.Microscopy.Com but I am still receiving mail from this list. Thank you.
------------------ GINNY E. CRUZ Section of Immunopathogenesis, Institute of Immunological Science Hokkaido University : Kita Ku Kita-15 Nishi-7 Sapporo City 001 JAPAN Tel. No.: (011)716-2111 Ext. 5120 Fax No.: (011)736-9836 e-mail: gcruz-at-imm.hokudai.ac.jp ------------------
This is a good question, but you are not the first person asking it.
I think that the answer is simple. You have only considered the absorption of the sample to the signals rather than the primary electron beam.
We know that the BSE signal is produced by the interaction between the primary electrons and the atomic nuclei of the sample, while the X-ray signal is the side product of the interaction between the primary electron beam and the outer layer electrons of the atoms in the sample. As the depth increased, the primary electrons would loss some energy, they would loss the qualification to produce the high energy BSE at some stage, but they can still create the X-ray in a deeper or/and wider zone. Then, yes, you are right, we should also consider the absorption of the sample to the signals.
Hope this can help.
Regards,
Charlie Kong
wise-at-vaxa.cis.uwosh.edu wrote:
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } In Posteket al., as well as other SEM texts, it is stated that } characteristic x-rays are emitted from a deeper zone in the interaction } volume than backscattered electrons. If the depth at which signals are } emitted is a function of the energy of that signal, why are the lower } energy X-rays (which have energies of ~1kV to ~20 kV at an accelerting } voltage of 25 kV) coming from a deeper depth than BSE (which would have } energies of ~25 kV)? } } Bob } } Dr. Robert R. Wise } Department of Biology } University of Wisconsin-Oshkosh } Oshkosh, WI 54901 } } (920) 424-3404 tel } (920) 424-1101 fax } wise-at-uwosh.edu
Dear Bob, That's easy, Bob. X-rays travel further through solid material than electrons, probably because they are heavier ;-) You wrote: } In Posteket al., as well as other SEM texts, it is stated that } characteristic x-rays are emitted from a deeper zone in the interaction } volume than backscattered electrons. If the depth at which signals are } emitted is a function of the energy of that signal, why are the lower } energy X-rays (which have energies of ~1kV to ~20 kV at an accelerting } voltage of 25 kV) coming from a deeper depth than BSE (which would have } energies of ~25 kV)? } } Bob } } Dr. Robert R. Wise } Department of Biology } University of Wisconsin-Oshkosh } Oshkosh, WI 54901 Regards, Mary Mary Mager Electron Microscopist Metals and Materials Engineering University of British Columbia 6350 Stores Road Vancouver, B.C. V6T 1Z4 CANADA tel: 604-822-5648 fax: 604-822-3619 e-mail: mager-at-interchg.ubc.ca
I wonder if anybody can help a colleague of mine? She is in need of= :
"a conical molybdenum insert cap for a Wehnelt asembly used in a Philips 500 series SEM, when fitted with a low kV anode"
I don't understand the question, so please can any replies be addressed directly to:
Ann.Hayes-at-bbsrc.ac.uk
Many thanks in advance!
Nigel Chaffey
----------------------------------------------------- Dr Nigel Chaffey, Dept Forest Genetics & Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Ume=E5, Sweden Phone: +46-90-786-6305 =46ax: +46-90-786-5901 eMail: nigel.chaffey-at-genfys.slu.se
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Dear Paula,
The opinion of my company is a life expectancy of 10 years. The depreciation is calculated based on that period and the microscope will be replaced after 10 years.
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Hello, everyone,
For the purposes of equipment replacement, costing for microscopy, as well as other reasons our Admin people have asked me to tell them what the life expectancy of electron microscopes is. We need to know this value because it is an integral part of any calculations we have to do with respect to our microscopes.
I have worked on both TEMs and SEMs that have been close to 25 years old, and still running well enough to allow us to get the information we required. I have also talked with some colleagues who have given 10 years as the expectancy, when the equipment, although it still may be working well, is considered to be "outdated".
In this vein, I would be interested to hear from colleagues and commercial folks alike to see what the general consensus is, and what a reasonable value for life expectancy is. This is important because this is the value I will always use in all my calculations from now on.
Thank you.
Paula Allan-Wojtas Food Microstructure Specialist Agriculture and Agri-Food Canada Atlantic Food and Horticulture Research Centre Kentville, Nova Scotia Canada B4N 1J5
} } I need to prepare TEM specimens of Inconel 718 superalloy . I was going to start with perchloric and ethanol at about - 35 C. I would however appreciate getting "recipes" from people with more experience on this matter. { {
Hi Jordi,
we routinely prepare TEM specimen from superalloys, both single crystal and poly crystalline (e.g. SC16, IN738 etc.) for our study of deformation substructure. We use twin jet polishing technique under following condition and get good sucess:
10% perchloric acid + 90% ethanol at 263 K and 23 V
It should work equally good for IN718. Wish you sucess.
-- Dr. D. Mukherji Group NM, Hahn Meitner Institut Glienicker Strasse 100 D-14109 Berlin, Germany Tel. (030) 8062 3099 Fax. (030) 8062 3059
The best journal for your paper if it is good science is, of course the Journal of Microscopy. Contact Sue Betteridge at jmicrosc-at-rms.org.uk for details.
Patrick Echlin General Editor Journal of MicroscopyOn Wed, 5 Nov 1997, Soumitra Ghoshroy wrote:
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } Hi Fellow Microscopists, } } I need some advice. What would be a good journal to publish a technical } advance type of paper which reports a methodological improvement for } immunoEM studies of plant tissues ? } } Thanks in advance, } } Soumitra } } Soumitra Ghoshroy } Department of Biochemistry and Cell Biology } State University of New York at Stony Brook } Stony Brook, NY 11794-5215 } Tel: 516-632-9536 } Fax: 516-632-8575 } } }
I need some advice. I was asked to do some analysis of silica particles (size distribution) for chemist in our institute. Particle size should be in the range of 3 to 6 um. I do not have any experiences with such sample. Could someone give me a tip how to prepare sample for TEM (or SEM)?
Thanks in advance, O. Benada
+---------------------------------------------------------------+ Oldrich Benada Acad. Sci. CR Phone: +420-2-4752399 Institute of Microbiology Fax: +420-2-4715743 Electron Microscopy Group E-mail: benada-at-biomed.cas.cz Videnska 1083 CZ - 142 20 Prague 4 - Krc Czech Republic +---------------------------------------------------------------+
There are few ways that I have had sucess at preparing paper cross-sections. The most commonly use method involves embedding in a low viscosity resin (Spurr's) and facing the cross-section with an diamond ultramicrotomy knife. The alternative method is to prepare the sample similary to a metallurgical specimen. Again using a low viscosity resin rather than standard epoxies.
The problem with epoxies will arrise with the FT-IR analysis. I have nerver tried this method, but you might infiltate sample with water and try cryomicrotomy. This will work as long as you do not mind swelling of the paper.
If you need more information, contact me at john_catino-at-ucamp.com
3D reconstruction from TEM images requires high resolution digital images. With the use of scanners with spot sizes of down to 7 microns a single sheet of em film produces a huge image file. With the need to collect hundreds/thousands of such images to improve resoultion/noise in reconstructs what are peole doing to store all these files? The files need to be stored so that they can be retrieved sensibly so tape archiving is not suitable. Is the technology available and at what cost?
Looking forward to a stimulating discussion.
Chris
Chris Gilpin Biological Sciences Electron Microscope Unit G452 Stopford Building Oxford Road Manchester M13 9PT phone +44 161 275 5170 fax +44 161 275 5171 http://www.biomed.man.ac.uk/biology/emunit/emhome.html
From all sources which I have read indicate that all else being equal, x-rays are more penetrating than electrons. That is to say that for electrons and x-rays of equal energy electrons are more easily shielded. "Hair splitter": Emission of x-rays and generation of BSEs can occur anywhere in the volume, only the more penetrating x-rays make it to the surface from a larger volume.
Woody White, Electron Microscopist SEM/EDS/WDS
Work: Mcdermott Technology, Inc. woody.n.white-at-mcdermott.com http://www.mtiresearch.com/
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In Posteket al., as well as other SEM texts, it is stated that characteristic x-rays are emitted from a deeper zone in the interaction volume than backscattered electrons. If the depth at which signals are emitted is a function of the energy of that signal, why are the lower energy X-rays (which have energies of ~1kV to ~20 kV at an accelerting voltage of 25 kV) coming from a deeper depth than BSE (which would have energies of ~25 kV)?
Bob
Dr. Robert R. Wise Department of Biology University of Wisconsin-Oshkosh Oshkosh, WI 54901
(920) 424-3404 tel (920) 424-1101 fax wise-at-uwosh.edu
Absorbance of X-rays is lower then absorbance of electrons.
wise-at-vaxa.cis.uwosh.edu wrote: } } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } In Posteket al., as well as other SEM texts, it is stated that } characteristic x-rays are emitted from a deeper zone in the interaction } volume than backscattered electrons. If the depth at which signals are } emitted is a function of the energy of that signal, why are the lower } energy X-rays (which have energies of ~1kV to ~20 kV at an accelerting } voltage of 25 kV) coming from a deeper depth than BSE (which would have } energies of ~25 kV)? } } Bob } } Dr. Robert R. Wise } Department of Biology } University of Wisconsin-Oshkosh } Oshkosh, WI 54901 } } (920) 424-3404 tel } (920) 424-1101 fax } wise-at-uwosh.edu
We have an immediate opening for an electron microscopist to perform microstructure studies on magnetic materials, including small particles, thin films/multiilayers, and permanent magnets. The Electron Microscopy Lab (Physics and Astronomy Dept., University of Delaware) consists of a Jeol JEM 2000 FX, a Jeol JEM 100 CX, and an Amray 1200 SEM.
The position is for one year initially, and can be renewed for the next three years.
Interested parties please respond by sending a resume and names and contact information for three references:
(a) by FAX to George Hadjipanayis at 302-831-1637 or
(b) by e-mail to: pmusa-at-udel.edu (Only in ASCII text or as part of a regular e-mail message, please.)
The University of Delaware is an Equal Opportunity Employer.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Patricia Meadows e-mail: pmusa-at-udel.edu Physics & Astronomy Dept. Phone: 302-831-2662 University of Delaware FAX: 302-831-1637 Newark, DE 19716-2570, USA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Another fine microscopy journal, if it is good science, is MICROSCOPY AND MICROANALYSIS, the official journal of the Microscopy Society of America, the Microbeam Analysis Society, the Canadian Microscopical Society, and the Mexican Microscopy Society. It is published by Springer-Verlag.
For information you can consult the journal's web site:
A. Kent Christensen Department of Anatomy and Cell Biology Medical Sciences II Building University of Michigan Medical School Ann Arbor, MI 48109-0616 akc-at-umich.edu Tel (313) 763-1287 http://www.umich.edu/~akc/
-----------------------------------------
} } } } Hi Fellow Microscopists, } } } } I need some advice. What would be a good journal to publish a technical } } advance type of paper which reports a methodological improvement for } } immunoEM studies of plant tissues ? } } } } Thanks in advance, } } } } Soumitra } } } } Soumitra Ghoshroy } } Department of Biochemistry and Cell Biology } } State University of New York at Stony Brook } } Stony Brook, NY 11794-5215 } } Tel: 516-632-9536 } } Fax: 516-632-8575 } } } } } } } }
Sorry for being a little slow, but I see no one else has responded to the list regarding your inquiry.
With regards to your question about "loosinging" the cells that's easy. I've worked with flask grown cultured cells a number of times, the easiest method for dealing with surface attached cells (generally in the retangular, lay-down 'plastic' culture flasks) is to:
(1) dump out the media
(2) add the fixative directly into the flask (make sure you use enough to cover the cell layer)
(3) Wait for the recommended primary fix length (hopefully someone else will provide information on appropriate fix and times) and dump out fix.
(4) rinse with appropriate rinse agent (i.e. buffer? unless ddH2O is preferred).
(5) Dump out first rinse, add second (to reduce residual fixative remaing, and make things safer) With a flask scraper (ask the dermatologist providing the sample for one - they look like tiny rubber window washer squeegies attached with a small hinge on the end of a plastic handle, they use these for transferring cells from one flask to another, and are designed to gentlely remove cells adherent to flasks) gentlely scrap the cells from the surface of the flask. Following fixation I have found that confluent cell layers adhear toe ach other very nicely and come off as strips and small sheets (i.e. 1-3mm x 1-3 mm x 1-3 cells deep). With extra buffer rinse these cell 'strips' into a test-tube or vial.
(6) Allow the cells chunks to settle, or breifly centrifuge LIGHTLY. And remove most of the excess rinse buffer. This should give you a concentrated suspension to work with.
(7) Mix the concentrated cell suspension with ~ equal amount of COOL (~ 45 -50 C) 2-4% agar/agarose in H2O. NOTE: Agar/agarose must be heated to ~100 C to get it into suspension but then doesn't gel until ~41C. I have found a 45C water bath ideal for keeping agar/agarose molten and at the right temperature. BUT it will set up very rapidly if you add cold cell suspension to 45 C agar/agarose. Since the cells are grown at 37C any way warming the fixed cells to 45C with the Agar/agarose should not cause problems.
(7) You can use epindorf tubes to mold the cell/agar mix or mix rapidly and poor out into a clean/sterile petri dish. Dice up either solidified mixture with a razor blade, and treat the agar/cell blocks just like any other tissue. If you osmicate, the agar will not turn black but the cells will (making them easier to find!). Remember that the 'agar' will be ~1-2% stuff and 98-99% empty space so infiltration into the agar is not much of a problem.
(8) The agar doesn't pick up much EM staining (little more LM staining) and exhibits only slightly greater electron density than empty resin.
Good luck.
Richard E. Edelmann, Ph.D. Electron Microscopy Facility Supervisor 352 Pearson Hall Miami University, Oxford, OH 45056 Ph: 513.529.5712 Fax: 513.529.4243 E-mail: edelmare-at-muohio.edu
"640K ought to be enough for anybody." -- Bill Gates, 1981
Would anyone know details of suppliers where Uranyl acetate can be obtained already in solution i.e. a saturated solution in 50% ethanol. We previously made this up ourselves from dry powder and ethanol, but we are trying to reduce the potential hazzard to health by purchasing ready made solution. Thanks on advance Orla O'Shea, Dept of Anatomy, QUB o.oshea-at-qub.ac.uk
I was just reading a section in Russ's book (Handbook of Image Processing, CRC Press) on using some gray-processing kernels that are sensitive to texture. I haven't tried this, and have no idea about software, but the examples in the book make it seem worth a try.
TEM - Input required for procedure to stain poly(4-vinyl pyridine).
I am interested in observing domain size in a block copolymer film of composition; poly(styrene-b-4-vinyl pyridine). So far I have made an attempt using OsO4 without any success. I could give RuO4 a try but I understand that it will likely stain the polystyrene as well. Any suggestions?
Thanks to all of you who responded to my inquiry about where to publish a technical advance paper. It was a great help.
Soumitra
Soumitra Ghoshroy Department of Biochemistry and Cell Biology State University of New York at Stony Brook Stony Brook, NY 11794-5215 Tel: 516-632-9536 Fax: 516-632-8575
In message {2.2.32.19971106062706.008f35bc-at-pop.unixg.ubc.ca} , Mary Mager {mager-at-unixg.ubc.ca} writes } That's easy, Bob. X-rays travel further through solid material than } electrons, probably because they are heavier ;-)
Photons are only heavier in reciprocal space of course. Outside of the electron microscope they will revert to their normal mass :-)
The mechanism of absorbtion is somewhat different. Electrons are simply scattered to lower and lower energy. You get a typical 1/E2 billiard ball kinematics curve for the absorbtion. But photons can be absorbed as quanta so the absorbtion curve for x_rays is a complex shape with distinct 'edges'.
The matter of incident beam path is an additional factor, significant but not primary (I think).
-- Usual disclaimers. Anthony James Bentley Surface Data Scientific Instrumentation and Software Web site http:\\www.surface.demon.co.uk
The generation of X-rays in terms of depth in the interaction volume is determined by several factors. X-rays will be produced throughout the volume until the energy of the x-ray is below the ionization energy of the core level responsible for that x-ray. Characteristic x-rays from different elements are generated from different volumes having different depths and the depths are strongly dependent on composition of the sample. In general, the depths of these volumes are deeper for lower edge energies and are deeper for lower average atomic number samples. The x-rays have a longer mean free path in a material than an electron; the measure of this is in the value of the cross section for scatterring. The absorption of an x-ray is an all or nothing proposition, once it is absorbed, it is gone. However, the electron can lose some of its energy during a scatterring event. The backscatterring process is occurring deeper in the sample, but the electron is loosing its energy on the way out of the sample. All of the electrons having energies from 50 eV (by definition) up to the primary are essentially backscattered electrons. There is a peak in the distribution near the primary energy. The electrons in this peak are coming from the near surface region because they haven't lost much energy. Incidently, this is why Auger electron spectroscopy is so suface dependent. The Auger electron generation process is also occurring with in the electron interaction volume below the surface, but they loose their characteristic energy on their trek to escape from the sample surface. They just get lost in the middle of the backscattered electron distribution and contribute to the background in the Auger spectrum.
In terms of imaging, a backscattered image will always have a poorer spatial resolution for a bulk sample than the secondary electron image. The lower the atomic number of the sample, the poorer the backscattered resolution will be for a given energy. If you lower the beam energy, you will improve the backscattered resolution, but you will be sacrificing detection efficiency of the backscattered elctrons. An x-ray map image will have poorer spatial resolution than a backscattered image.
Hope this helps.
-Scott
Scott D. Walck PPG Industries, Inc. Guys Run Rd. (packages) P.O. Box 11472 (letters) Pittsburgh, PA 15238-0472
(412) 820-8651 (office) (412) 820-8161 (fax)
"The opinions expressed are those of S.D. Walck and not of PPG Industries, Inc. nor of any PPG-associated companies."
In Posteket al., as well as other SEM texts, it is stated that characteristic x-rays are emitted from a deeper zone in the interaction volume than backscattered electrons. If the depth at which signals are emitted is a function of the energy of that signal, why are the lower energy X-rays (which have energies of ~1kV to ~20 kV at an accelerting voltage of 25 kV) coming from a deeper depth than BSE (which would have energies of ~25 kV)?
Bob
Dr. Robert R. Wise Department of Biology University of Wisconsin-Oshkosh Oshkosh, WI 54901
(920) 424-3404 tel (920) 424-1101 fax wise-at-uwosh.edu
This is more visual optics than microscopy, but can anyone direct me to a good explanation of the visual phenomenon called Haydinger's Cross? This refers to the ability of the human eye to visualize a maltese cross pattern when looking at a white field, with a blue bar in one direction and a yellow bar at 90 degrees. It is apparently caused by some kind of dichroism in the eye.
Gary Radice, Associate Professor gradice-at-richmond.edu Department of Biology 804-289-8107 (voice) University of Richmond VA 23173 804-289-8233 (FAX)
You didn't mention the file size, but for large images files I have been using a writeable CD (CD-R). It is anyone's guess how long technology will be around to read the CDs, but seems the best bet at this time. DVDs are a coming possibility for even more storage. The last blank CDs I bought were {$1.50 each. For 650 megs of storage, "that ain't bad".
Woody White, Electron Microscopist SEM/EDS/WDS
Work: Mcdermott Technology, Inc. woody.n.white-at-mcdermott.com http://www.mtiresearch.com/
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Dear List
3D reconstruction from TEM images requires high resolution digital images. With the use of scanners with spot sizes of down to 7 microns a single sheet of em film produces a huge image file. With the need to collect hundreds/thousands of such images to improve resoultion/noise in reconstructs what are peole doing to store all these files? The files need to be stored so that they can be retrieved sensibly so tape archiving is not suitable. Is the technology available and at what cost?
Looking forward to a stimulating discussion.
Chris
Chris Gilpin Biological Sciences Electron Microscope Unit G452 Stopford Building Oxford Road Manchester M13 9PT phone +44 161 275 5170 fax +44 161 275 5171 http://www.biomed.man.ac.uk/biology/emunit/emhome.html
Message-Id: {199711061738.RAA06198-at-highgate.mluri.sari.ac.uk} Comments: Authenticated sender is {mi596-at-highgate}
Can anybody explain to me exactly how a film thickness monitor for Au and C coating works. I understand it consists of an oscillating crystal -what is it made of? I have heard accuracy is poor but reproducability is good using same conditions (time, current, working distance etc.). Thickness of C is important from the point of view of quantitative analysis and that unknowns must be coated with the same thickness as the reference standards. Is it sufficient to say to NAMAS or ISO accreditors that the same coating conditions were used for the standards as well as unknowns. Many thanks in advance.
Martin J. Roe MLURI Craigiebuckler Aberdeen AB158QH Scotland U.K.
There is a error in the listing of the program LENZPLUS.BAS on page 429 of the second edition of Electron Energy-Loss Spectroscopy in the Electron Microscope (Plenum, 1996): line 135 should contain ^3*, not ^*. However, this is a typographical error and the program listing at the ftp site (ftp.phys.ualberta.ca) has always been correct.
In addition, error-free execution of the Kramers-Kronig program KRAKRO.FOR, as listed on p.415, requires that the array D be dimensioned as D(8192) in the FFT subroutine, not D(4096) as required on p.413. I have recently made this change to the ftp-site listing.
I am not aware of any other significant errors in the Second Edition but would be grateful for any feedback from readers.
Ray Egerton, Physics Dept, University of Alberta, Edmonton, Canada T6G 2J1 Phone: 403-492-5095, FAX: 403-492-0714, e-mail: egerton-at-phys.ualberta.ca ------------------------------------------------------------------------
} I need some advice. I was asked to do some analysis of silica } particles (size distribution) for chemist in our institute. Particle } size should be in the range of 3 to 6 um. I do not have any } experiences with such sample. Could someone give me a tip how to } prepare sample for TEM (or SEM)? } } Thanks in advance,
} Probably the best way to prepare these samples is to dilute them in a solution of distilled water and to disperse them for several minutes in an ultrasonic bath. Pipette a small drop of the suspension on to a small glass slide (mounted on to a SEM stub by means of a carbon adhesive tab) and allow sample to dry. Coat the samples with a thin layer of Au or Au-Pd and examine in the SEM. You could also try dipping an SEM stub (with a carbon adhesive tab stuck on it) directly in to the sample and blowing off the excess with a Dust-off spray and then coat the sample. I suggest you try the latter of these two options first
Re: particle sizing. I don't do EM, but I do particle size measurements by light scattering and other techniques, using LM to confirm measurements qualitatively for micron sized particles. Microscopy looks at very few particles, so if you care about a measurement that will be valid for a much larger quantity, you really have to think hard about getting a representative sample. This is not easy.
A possibly useful reference is "Sampling for Chemical Analysis," B. Kratochvil, D. Wallace, & J. K. Taylor, Anal Chem. vol 56, 113R-129R (1986).
Leonard Corwin Fort Dodge Animal Health Princeton NJ 08543-0400
Does anyone know of a source of glutaraldehyde powder? We would like to try glut in acetone and other solvents for freeze-substitution, but glut comes only in ethanol as far as I can tell. I suppose we could dry it down from 70% solution, or does this alter it chemically??
TIA,
Rosemary White Department of Biological Sciences Monash University, Melbourne, Victoria 3168, Australia phone 61-3-9905 5670 fax 61-3-9905 5613 email r.g.white-at-sci.monash.edu.au
Hello, I just read a reply to your inquiry. I have prepared cultured cells, too. I suggest initially using a rubber policeman pushing with constant pressure..and not lifting anymore than necessary to get sheets of cells off the dish. Use the solution in dish to flush cells to one edge. I then use a large bore pipette to pick up cells and place into a microfuge (Eppendorf) tube, let the cellular material settle for a minute or two. Then take off the supernatant, leaving cells and just enough solution to keep them covered. Now add your fixatice, ten times the cellular volume, gently mixing. I usually used a modified Karnovsky in buffer for our cells, then centrifuge at a low speed, about 500 rpms, for 10 minutes. If you have enough cells to have a pellet then you don't have to add agar. Continue to fix for at least an hour. If your pellet is large, you will need to loosen it carefully so subsequent solutions can get in from top and bottom. If pellet size is small, all processing can be done in the tube, even the embedding. Just don't fill tube to top, for the polymerizing step, with more media than one would put into a BEEM capsule. After polymerizing, the tube can be cut off and the sides can be trimmed flat to fit into a microtome chuck.
I found that if I first fixed the cells, then tried to scrape them, that too many of them were ruptured. It may be that your cells are not so fragile. Anyway, I then would only recommend a very brief fix before scraping. Kaye
(Roberta) Kaye Brabec, Manager E-mail: brabec-at-umich.edu Morphology Core Facility, Box 0616 Phone: (313) 763-0150 4742 Med Sci II, U of MI Fax: (313) 763-1166 Ann Arbor, MI 48109-0616
I am looking to use a 3-CCD RGB camera that will integrate for at least 5 seconds.
I need to use it to image 3-color FISH samples.
I was wondering if anyone out there has any experience with 3-CCD RGB cameras and can give me some information on a camera that will perform well in terms of resolution, image quality, etc.
We use a twin-jet electropolishing unit to prepare TEM foils of superalloy. We tested several polishing solutions employing a variety of conditions. The best results for our alloys (SRR99 and Udimet 720) were obtained in the use of a solution and condition as following:
Solution: 25% Nitric acid in 75% Methanol Current 0.10 mA Voltage 34~36 V Temperature -35 ~ -45 0C
Good Luck!
Peiyi Wang
Research Fellow Dept. of Engineering Materials University of Southampton Southampton SO17 1BJ UK
} } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } } I need to prepare TEM specimens of Inconel 718 superalloy . I was } going to start with perchloric and ethanol at about - 35 C. I would however } appreciate getting "recipes" from people with more experience on this } matter. } } Thanks } } Jordi Marti }
Our lab does a lot of work with semiconductors. My concern is with the preparation of InP, InGaAsP, GaAs, GaP, etc. What are the hazards with these materials? What sort of precautions are required when cutting, grinding and polishing the wafers? I'm finding it difficult finding any safety related information regarding the use of these materials in an EM lab. Thanks in advance.
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I have lots of experience preparing GaP and GaAs TEM samples. One precaution, GaP reacts with water to produce phosphine, a particularly nasty gas. Phosphine is pyrophoric, so don't be surprised if your samples explode on you if you core out 3 mm disks using an ultrasonic disk grinder. It's happened to me on several occasions. Also, do all your sample prep in a fume hood. While the levels of phosphine emitted by the sample are small (so I assume since I haven't killed myself, yet). You'll get a painful headache from small exposures to the gas. For GaAs, I'm unaware of any similar health issues and have had no difficulties working with this material on an open bench top.
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Our lab does a lot of work with semiconductors. My concern is with the preparation of InP, InGaAsP, GaAs, GaP, etc. What are the hazards with these materials? What sort of precautions are required when cutting, grinding and polishing the wafers? I'm finding it difficult finding any safety related information regarding the use of these materials in an EM lab. Thanks in advance.
I 've been asked if it's possible to use microscopy to count ultrafine particles (smaller than 0.1 microns) and to measure their size distributions in an automated fashion. The primary goal is to characterize ultrafines in ambient air. Particles larger than 0.1 microns are typically collected on a screen membrane such as polycarbonate. Most of the ultrafines however would pass through the smallest pores in screen-type membranes. My question is really two-fold: 1) Is it even possible to collect ultrafines for microscopy, and 2) Which technique would be best suited to count and size the ultrafines -- SEM, FE-SEM, TEM, AFM? Or should we just forget microscopy and purchase some particle sizing/counting instrumentation? Thanks for your ideas.
South Bay Technology, Inc. is offering a series of TEM Sample Preparation=
Workshops which will be kicked off with a workshop on RF Plasma Cleaning for TEM and SEM applications. This workshop will be held on Monday December 1, 1997 in Boston, MA.
For a detailed workshop description and registration information on the Plasma Cleaning workshop, please contact me off line and I will forward t= he information to you.
Other upcoming workshops include:
Tripod Polishing for TEM March 13-14, 1998 San Clemente, CA Low Energy on Milling March 12, 1998 San Clemente, CA Plasma Cleaning for TEM March 11, 1998 San Clemente, CA MicroCleave Techniques =
for TEM Sample Preparation March 10, 1998 San Clemente, CA
For information on any of these workshops, please contact me.
South Bay Technology, Inc. is offering a series of TEM Sample Preparation=
Workshops which will be kicked off with a workshop on RF Plasma Cleaning for TEM and SEM applications. This workshop will be held on Monday December 1, 1997 in Boston, MA.
For a detailed workshop description and registration information on the Plasma Cleaning workshop, please contact me off line and I will forward t= he information to you.
Other upcoming workshops include:
Tripod Polishing for TEM March 13-14, 1998 San Clemente, CA Low Energy on Milling March 12, 1998 San Clemente, CA Plasma Cleaning for TEM March 11, 1998 San Clemente, CA MicroCleave Techniques =
for TEM Sample Preparation March 10, 1998 San Clemente, CA
For information on any of these workshops, please contact me.
Oldrich Benada wrote: ===================================================== I need some advice. I was asked to do some analysis of silica particles (size distribution) for chemist in our institute. Particle size should be in the range of 3 to 6 um. I do not have any experiences with such sample. Could someone give me a tip how to prepare sample for TEM (or SEM)? ====================================================== The problem is that those pesky silica particles don't know that they are supposed to separate and stay away from each other when dispersed in a liquid followed by a droplet of this liquid suspension being placed on a solid surface. They tend to agglomerate very quickly leading to a difficult- to-analyze situation, especially using automated means of analysis. You are correct in that the size range expected could be on the order of 3-6 nm.
This is the ideal application for the camphor/naphthalene method which I described several years ago. Credit for the technique, or at least the one who taught it to me was an innovative microscopist then working at the DuPont Experimental Station in Wilmington, DE by the name of Robert P. Schatz, in about 1968, now deceased. Take a 60% camphor/40% naphthalene mixture and heat it to twenty or so degrees above room temperature on a hot plate in a small beaker or flask, the two organics are miscible in each other and this is the eutectic composition.
Once a clear liquid, add a small amount of the silica (not more than 0.1%), which disperses quite readily. Then, using a pipette, take out some liquid and put a drop onto a carbon coated glass slide, at which time the drop is instantly frozen solid (it is at room temperature). Put the slide into your vacuum evaporator to pump out all night, and the "magic" is that the solid eutectic sublimes at room temperature at a rate that by morning, it is completely gone, leaving the silica particles uniformly dispersed on the carbon film!
The rest is obvious. You can pick this up on a grid, as is, or in order to bring out more contrast, Pt/C shadow, probably using an angle not more than 30 degrees. You can float the "replica" off of the slide directly onto a grid and viola! you have particles completely dispersed, virtually no doublets or triplets, and a field quite amenable for automated image analysis (as a bonus).
One important further suggestion: Some times these silica particles tend to fuse together as little "chains". If you suspect this is happening, be sure to take the micrographs as stereo pairs because you can in fact capture this three dimensional spatial information.
Disclaimer: We do not sell either the camphor or naphthalene so have no vested interest in whether people use this method or not. It is just a really neat method for the preparation of fine particle samples in this size range. We are obviously set up to use this method as a service for others, however.
Chuck
=================================================== Charles A. Garber, Ph. D. Ph: 1-(610)-436-5400 President 1-(800)-2424-SPI SPI SUPPLIES FAX: 1-(610)-436-5755 PO BOX 656 e-mail: cgarber-at-2spi.com West Chester, PA 19381-0656 USA Cust. Service: spi2spi-at-2spi.com
Look for us! ############################ WWW: http://www.2spi.com ############################ ==================================================
Dear Martin, I believe the film thickness monitors are quartz crystal oscillators that have the characteristic of changing their frequency of oscillation as their mass changes. As you evaporate carbon onto the monitor its mass goes up and the frequency of oscillation goes down. I don't know about the requirements of NAMAS or ISO. You wrote: } } Can anybody explain to me exactly how a film thickness } monitor for Au and C coating works. I understand it consists of an } oscillating crystal -what is it made of? I have heard accuracy is } poor but reproducability is good using same conditions (time, } current, working distance etc.). } Thickness of C is important from the point of view of } quantitative analysis and that unknowns must be coated with the } same thickness as the reference standards. Is it sufficient to } say to NAMAS or ISO accreditors that the same coating conditions were } used for the standards as well as unknowns. } Many thanks in advance. } } Martin J. Roe } MLURI } Craigiebuckler } Aberdeen } AB158QH } Scotland Regards, Mary Mary Mager Electron Microscopist Metals and Materials Engineering University of British Columbia 6350 Stores Road Vancouver, B.C. V6T 1Z4 CANADA tel: 604-822-5648 fax: 604-822-3619 e-mail: mager-at-interchg.ubc.ca
Dear Andy, When we worked with GaAs the only precautions were to gather all bits for proper disposal and avoid generating or inhaling any dust, ie. grind and polish wet. Also avoid excess heating because of the possibility of driving off As. You wrote:
} Our lab does a lot of work with semiconductors. My concern is with the } preparation of InP, InGaAsP, GaAs, GaP, etc. What are the hazards with } these materials? What sort of precautions are required when cutting, } grinding and polishing the wafers? I'm finding it difficult finding any } safety related information regarding the use of these materials in an EM } lab. } Thanks in advance. } } Andy
} Andy M. Duft } Brockhouse Institute for Materials Research } McMaster University } 1280 Main St. West } Hamilton Ontario } Canada L8S 4M1 } } 905-525-9140, X24609 Regards, Mary Mary Mager Electron Microscopist Metals and Materials Engineering University of British Columbia 6350 Stores Road Vancouver, B.C. V6T 1Z4 CANADA tel: 604-822-5648 fax: 604-822-3619 e-mail: mager-at-interchg.ubc.ca
Thanks to all who answered my question about interaction volumes, X-rays, and BSEs.
Stephanie Wind McCray (Moltech Corp) probably had the best answer (or at least the one I understood the best), "keep in mind that backscattered electrons are electrons, and x-rays are photons. There are somewhat different rules for their relative travels through matters of varying atomic numbers" There were a lot of other good answers too.
So (he says with a light bulb over his head), this is why hospitals take X-ray photographs of broken bones and not electron-graphs.
Thanks again
Bob
Dr. Robert R. Wise Department of Biology University of Wisconsin-Oshkosh Oshkosh, WI 54901
(920) 424-3404 tel (920) 424-1101 fax wise-at-uwosh.edu
Hello everybody, a question to the mineralogists on the list: as the German provider (Krantz) for storage boxes for mineralogical standard thin sections cannot provide them any longer I am looking for some other source, preferably in Europe. What I call "standard thin sections" are 28 x 48 mm sized. Thank you in advance Hiltrud
Dr. Hiltrud Mueller-Sigmund Institut fuer Mineralogie, Petrologie und Geochemie Albertstrasse 23b, 79104 Freiburg (Germany) Tel.: (+49)-203-6388/-6396 Fax: -6407
"Calibration of an Off-Axis Quartz Crystal Thickness Monitor for a Pulsed Laser Deposition System Using a High Resolution Scanning Electron Microscope", S. D. Walck, J. S. Zabinski, M. S. Donley, and J. E. Bultman, Thin Solid Films, 236, pp. 125-9, 1993.
If you look that paper up, I bleive that there are two excellent references in there on how a thickness monitor works. One of them is a journal article that apparently is a classic and the other is a reference manual for the XTC quartz crystal thickness monitors. These references talk about some of the limitiations on the technique and accuracies etc. I would give you the references myself, but my papers are still boxed up from my move to PPG -sorry. You could contact Jeff Zabinski at Wright Patterson AFB and get a reprint of that paper since they have it on file there. He can be reached vis Email at zabinsj-at-ml.wpafb.af.mil
-Scott Walck
Scott D. Walck PPG Industries, Inc. Guys Run Rd. (packages) P.O. Box 11472 (letters) Pittsburgh, PA 15238-0472
(412) 820-8651 (office) (412) 820-8161 (fax)
"The opinions expressed are those of S.D. Walck and not of PPG Industries, Inc. nor of any PPG-associated companies."
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Good Afternoon, I've enjoyed reading the many postings on the Microscopy Listserver. Now I have a question for all of you...
Has anyone noticed a change in the quality of TEM Grids?
For years we've ordered our TEM grids from Biorad.... We've used the Thin bar Hexagonal 460 mesh copper and nickel grids for years. They were always very clean, very consistent in thin bar width, and of excellent quality.
Now that they are no longer selling them, we've been trying grids from several sources. I have done a comparison of grids from different companies. A number of them are close, but not quite as thin as the original Biorad grids. Others have too much variation in grid width (even within the same vial) and some are unacceptable, too wide, more like normal grid bars, and not thin bars....
Does anyone know the original source of the grids that Biorad used to sell? None of the companies we've tried have the quality we are looking for... some are close, but even within the same vial of grids, we've found too much variation in the grid bar width.
Thank you for your assistance,
Virginia Tanner Crocker
******************************************************************* Virginia Tanner Crocker Biologist NIH, NINDS EM Facility, Bldg 36, Room 3B24 Bethesda, MD 20892
There is a description of the phenomenon of "Haidinger's brush" (or cross) in "Condepts of Classical Optics" by John Strong, Freeman, San Francisco, 1958, P.111f. He quotes from a book by Minnaert, "The Nature of Light in the Open Air," Dover, New York. It demonstrates the ability of the naked eye to percieve polarization in light and the orientation of the plane of polarization. To quote from Minnaert: "If you have a Nicol (prism) at your disposal,then look through it at a white cloud - or at an evenly illuminated (white) surface and try to distinguish the figure by the fact that the it revolves when the Nicol is rotated......." "Haidenger's brush is caused by the dichroism of the yellow spot on our retina. That all observers do not, apparently, see this remarkable figure in the same way no doubt depends on the difference in shape and structure of this yellow spot...." Hope this helps. All the best, Andy Andy Buechele The Catholic University of America 409 Hannan Hall Washington, D.C. 20064 (202) 319-4995 FAX: (202) 319-4469
We have recently received samples of freeze-dried guar seeds for SEM processing. The researcher would like the seeds cut in half and evaluated with SEM. In their current state, the seeds crumble when cut. If anyone has any suggestions for processing, we could use the help!
Thanks in advance, Beckie Anderson Kansas State University College of Veterinary Medicine Department of Diagnostic Medicine/Pathobiology Electron Microscopy Laboratory
Thank you to Massimo Sassaroli, Rober Mixon, Richard Mount, Stephan Coetzee, Stephen Griffiths, and others who responded to the query on how to segregate the MSA e-mail from the rest.
With the help, I was able to set the IE e-mail browser ("Internet Mail and News") to recognize the "microscopy" keyword in either the "TO:" or the "CC" - fields which are invisible by default. It has worked without a glitch for a week now, so no need to try a different browser. It mystifies me why it has worked in few circumstances as I'm unable to manually find the keyword in either of the fields - maybe "it's a feature and not a bug", but that's beside the point.
Electron Microscopy Sciences has Anhydrous Glut. (10% in acetone) in 10ml ampules, cat# 16530.
Tom
Thomas Moninger moninger-at-emiris.iaf.uiowa.edu University of Iowa Central Microscopy Research Facility http://www.uiowa.edu/~cemrf Views expressed are mine. On Fri, 7 Nov 1997, Rosemary White wrote:
} } Dear all, } } Does anyone know of a source of glutaraldehyde powder? We would like to } try glut in acetone and other solvents for freeze-substitution, but glut } comes only in ethanol as far as I can tell. I suppose we could dry it down } from 70% solution, or does this alter it chemically?? } } TIA, } } } Rosemary White } Department of Biological Sciences } Monash University, Melbourne, Victoria 3168, Australia } phone 61-3-9905 5670 } fax 61-3-9905 5613 email r.g.white-at-sci.monash.edu.au } }
Please post responses to the list; I want to be safe too! :) Karen
o.oshea-at-queens-belfast.ac.uk wrote: } } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } Would anyone know details of suppliers where Uranyl acetate can be obtained } already in solution i.e. a saturated solution in 50% ethanol. We previously } made this up ourselves from dry powder and ethanol, but we are trying to } reduce the potential hazzard to health by purchasing ready made solution. } Thanks on advance } Orla O'Shea, Dept of Anatomy, QUB } o.oshea-at-qub.ac.uk
-- Karen Zaruba kszaruba-at-mmm.com 3M Company, St. Paul, MN 55144 "Opinions above are my own, not necessarily my employer's"
I have a question maybe someone could help me... I want to measure the size of my probe, but I collected the wrong image... i.e., I collected the image of the probe in the diffraction mode... Is it possible to find actual size of the probe? I think if I know the distance between the objective aperture and the selected area aperture and the point of convergence of the convergence angle, I should be able to calculate it from there... but where can I find all these information?... Can anyone help me?
I've done preps of individual cells on filters before with no particular problems. This one has me stumped.
I'm trying to get a prep of Scenedesmus cells onto a filter membrane for fixation, CPD, sputtering. Seems straightforward. These cells fly away from the Nucleopore (PC) or Millipore (cellulose ester) membranes when I transfer to a liquid after depositing the cells by gentle suction. One protocol I tried called for poly-L-lysine treated glass, but the cells failed to stick to this also. The microbiologist who is involved tells me that the cell surface is nearly pure cellulose and does not have the substances that give a negative charge and would make the polylysine work. SOME cells do stick to the filter surface but many do not and we don't know if this gives a selection for a subset (and we want to see them all).
Are algae this different? Are there tricks with the polylysine? Is there another method?
If anyone has any suggestions that could help me I would really appreciate hearing them.
Thanks in advance!
Dale Callaham (dac-at-bio.umass.edu) +++++++++++++++++++++++++++ Dale A. Callaham Central Microscopy Facility The University of Massachusetts Amherst, MA 01003 +++++++++++++++++++++++++++
Minnesota Microscopy Society Meeting November 20, 1997, Thursday
Atomic Force Microscopy & Related Techniques: Introduction, Instrumentation & Application to Polymeric Materials by Inga Holl Musselman, Assistant Professor of Chemistry, University of Texas, Dallas
University of Minnesota, St. Paul Campus Student Center, The Pendergast Room
5:30 - 6:00 Social with Appetizers Cheese - Crackers - Hot Apple Cider
Atomic force microscopy (AFM) was introduced by Binnig, Quate and Gerber in 1986. In this method, a sample is scanned beneath a small probe attached to the apex of a flexible cantilever. Cantilever deflection is measured to give height information corresponding to the sample topography. Since AFM relies on tip-sample force interaction, the technique can be applied to insulators as well as to conducting and semiconducting materials. AFM therefore extends local probe studies to an important class of materials which can be difficult to investigate by electron microscopy and spectroscopy techniques owing to problems with sample charging.
During the past decade, related force microscopy methods have been developed to facilitate the study of surfaces in a variety of environments using a number of contrast mechanisms. Among others, these methods include contact, non-contact and TappingMode atomic force microscopy, lateral force microscopy, force modulation, phase imaging, electrostatic force microscopy, magnetic force microscopy, scanning capacitance microscopy, scanning near-field optical microscopy, and scanning near-field thermal microscopy. This presentation will review the theory and instrumentation for some of these microscopy methods and will emphasize their application to polymer materials.
Biography: Inga Holl Musselman is an Assistant Professor of Chemistry at the University of Texas at Dallas. She received a Ph.D. in Analytical Chemistry in 1988 from the University of North Carolina at Chapel Hill. Her Ph.D. research project, concerning molecular and quantitative aspects of laser microprobe mass spectrometry (LAMMS), was conducted at the National Institute of Standards and Technology. During a postdoc in the Department of Materials Science and Engineering and Precision Engineering Center at North Carolina State University, her research efforts concerned the fabrication of controlled geometry tips for scanning tunneling microscopy (STM) (patent and license awarded). In collaboration with Hoechst Celanese, she also investigated the application of scanned probe techniques to the characterization of polymer surfaces. Currently, Dr. Musselman's research group is investigating the fundamentals of STM image contrast. In addition, they are using atomic force microscopy and other microscopy methods to characterize the microstructure of synthetic and biopolymers including gas separation membranes and paired helical filaments from Alzheimers diseased brains.
PLEASE MAKE RESERVATIONS by November 18th. Contact: Gib Ahlstrand at (612)625-8249, 625-9728FAX, or: giba-at-puccini.crl.umn.edu.
Dinner and Social Hour: $10.00 per person, payable at the door. Free for current student members or with new sudent membership,payable at the door. Presentation is free for those who come later for the talk only.
Social hour, dinner and the presentation will all be held in the Pendergast Room, second floor level of the St. Paul Campus Dining Center (across hall from Cherrywood Room) of the University of Minnesota. This location will be familiar to some who have attended our meetings there before. Parking is available in the lots indicated with cross-hatching below:
Directions: From I-94, take I-280 a few miles north and exit onto Larpenteur Ave., go eastbound 1 mile to Cleveland Ave. plus 1 block to Gortner Ave. From I-35W or Hiway 36 take Cleveland Ave. south to Larpenteur, turn left go 1 block to Gortner Ave. Turn right onto Gortner and go south to Buford Ave., turn right , go 1 block to Buford Circle, turn right and proceed 1 block to parking lots (see map). Enter Dining Center as indicated.
--
Gib Ahlstrand, MMS Newsletter Editor Electron Optical Facility, University of Minnesota, Dept. Plant Pathology 495 Borlaug Hall, St. Paul, MN 55108 (612)625-8249 612-625-9728 FAX, giba-at-puccini.crl.umn.edu
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } There is a description of the phenomenon of "Haidinger's brush" (or } cross) in "Condepts of Classical Optics" by John Strong, Freeman, San } Francisco, 1958, P.111f. He quotes from a book by Minnaert, "The } Nature of Light in the Open Air," Dover, New York. It demonstrates } the ability of the naked eye to percieve polarization in light and } the orientation of the plane of polarization. To quote from Minnaert: } "If you have a Nicol (prism) at your disposal,then look through it at } a white cloud - or at an evenly illuminated (white) surface and try } to distinguish the figure by the fact that the it revolves when the } Nicol is rotated......." } "Haidenger's brush is caused by the dichroism of the yellow spot } on our retina. That all observers do not, apparently, see this } remarkable figure in the same way no doubt depends on the difference } in shape and structure of this yellow spot...." } Hope this helps. } All the best, } Andy } Andy Buechele } The Catholic University of America } 409 Hannan Hall } Washington, D.C. 20064 } (202) 319-4995 FAX: (202) 319-4469 } There is another description of what is called an "Optic Axis Interference Figure" in Nesse, William D, Introduction to Optical Mineralogy, Second Edition 1991, Oxford university press. While I realize the application may be different, the figure is the same (caused the same way) and the book gives a somewhat detailed account of how the figure (cross) is formed, and what the colors (blue and yellow) and the positions of the colors in the cross mean. Along with a description of how these crosses are used to help identify minerals in petrographic sections (though most of you could probably care less :)).
Reichert makes an automatic grid stainer that uses prepared stains (called the "Ultrostainer"). Maybe they would be a potential supplier for premixed uranium stains.
Bob Wise } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America
Rosemary White wrote: } } } Dear all, } } Does anyone know of a source of glutaraldehyde powder? We would like to } try glut in acetone and other solvents for freeze-substitution, but glut } comes only in ethanol as far as I can tell. I suppose we could dry it down } from 70% solution, or does this alter it chemically?? }
Dear Rosemary,
Glutaraldehyde monomer is notoriously unstable in aqueoussolutions above 70%. Glut polymerizes at high concentraions and is next to impossible to depolymerize. For these reasons I believe it would be inadvisable to dehydrate your 70% Glut. We at Ladd currently offer 20% Glut in anhydrous methanol (catalog # 20257 & 20258). We have produced a wide variety of glutaraldehyde combinations through the years and would be willing to prepare some glut in acetone and in other solvents. If you are interested please contact me direct and we can work out the particulars.
Dr. Charles Duvic Ladd Research 13 Dorset Lane Williston, VT 05495 USA tel 1-802-878-6711 fax 1-802-878-8074 e-mail ladres-at-worldnet.att.net
I've recently been handed a sample consisting of dust collected near a suspected pollution source. The sample was picked up on cotton swabs in an extremely non-scientific manner (off the hood of a car in the desert, and they want to know if silicon is present---go figure), and the client is looking for fiberglass particles, among other things. I have found fibers in the sample about 10-12 microns in diameter which resemble SEM photos I have seen of fiberglass.
My question is this: What elements would one expect to find in fiberglass, other than (obviously) silicon? I'm aware of calcium and aluminum being used in glass, but are there other commonly used elements? Specifically, barium? (5 distinct Ba peaks in this one!)
The sample is on a carbon stub using carbon adhesive tape. We're using a variable pressure SEM with 7 Pa of pressure. The EDS on the fibers is being done in spot analysis mode at a mag of 3000x. I'm reasonably confident that most of the signal is coming from the fiber itself, allowing of course for beam skirting, etc.
Thanks in advance for any advice.
Randy Tindall Electron Microscope Laboratory Box 3EML New Mexico State University Las Cruces, NM 88003
Thank you to all the people who responded to my question about how film thickness monitors work. I am now a lot more knowlegeable about the subject. All your replies were greatly appreciated.
The New England Society for Microscopy (NESM) presents its 31st Annual Fa= ll Symposium and Business Meeting on December 5, 1997 at the Hyatt Regency Cambridge, 575 Memorial Drive, Cambridge, MA 02139, Tel. (617) 492-1234.
PROGRAM: Friday, December 5, 1997
Session I =
9:00 am Registration and Continental Breakfast Note: The Registration Desk will close at 10:45 am and reopen for =
Session II from 1:00 to 1:30 pm
9:55 am Welcome =
Ann Hein, NESM President
10:00am "Characterization of Graphitic Carbon Spheres and Tubes Synthesized =
by a Mixed-Valent Oxide Catalytic Carbonization Process" Dr. Z. L. Wang School of Material Science and Engineering Georgia Institute of Technology
11:00am "Pathology of Laser Tissue Interaction" Thomas J. Flotte, MD Associate Professor of Dermatology, =
Harvard Medical School, Boston, MA Director of Dermatopathology, Massachusetts General Hospital =
12:15pm Luncheon with wine: Poached Atlantic Salmon, Chicken Picatta, or =
Vegetarian selections =
Session II =
1:00 pm Registration =
1:30 pm "Characterization of Translucent Polycrystalline Alumina Using SEM, =
Electron Probe and TEM" =
Dr. George Wei, Osram Sylvania
2:15 pm "Confocal Microscopy of Live Subjects" Robert H. Webb Wellman Laboratories of Photomedicine, MGH Schepens Eye Research Institute, Boston, MA
3:00 pm Coffee Break
3:15 pm "What Project MICRO Can Do For You" Caroline Schooley, MSA Education Outreach Coordinator =
NESM Annual Business Meeting 4:15 pm Counting of Ballots =
Reading of Minutes of 1996 Annual Business Meeting =
Report of the President Report of the Treasurer Introduction of New Officers =
5:00 pm Adjournment Louis Kerr, Incoming NESM President
For more information or to register, contact L. Kirstein at NESM-at-compuserve.com =
or by phone at (508) 473-9673. (Please include your fax number if you ha= ve not =
} The sample was picked up on cotton swabs in an } extremely non-scientific manner (off the hood of a car in the desert, and } they want to know if silicon is present---go figure)
Carnack says, "Yes!"
} ... the client is looking for fiberglass particles, among other things.
Randy, how can I put this? Um, "you're driving a thumb tack in with a sledge hammer?" Or, perhaps.... Nevermind. An SEM with EDXA is overkill for finding fiberglass. It is a trivial task with a polarized light microscope as all glass is transparent and isotropic and various other fibrous materials are either opaque or birefringent. In addition, the morphology will tell you if it is mineral wool, a course fibrous glass used most often in insulation, or true fiberglass, a more carefully prepared fibrous glass product used in a wider range of applications. The size you mention (10-12 microns) is certainly within the range one can encounter with either of these products, or other fibrous materials.
If you still have a bit of the swab(s) left, I would suggest the following. Place a portion of the soiled swab in a small centrifuge tube, add a bit of water with dilute detergent, ultasonicate for a few minutes, remove the swab, centrifuge, wash a couple of times, re-suspend and pipet a bit of the particulate debris onto a microscope slide. Mount in virtually anything and examine under a PLM with slightly uncrossed polars. Look for isotropic, fibrous strands. It takes longer to describe than it does to do!
} My question is this: What elements would one expect to find in fiberglass, } other than (obviously) silicon? I'm aware of calcium and aluminum being } used in glass, but are there other commonly used elements? Specifically, } barium? (5 distinct Ba peaks in this one!) }
But on the other hand, if an SEM is all you have....
As I mentioned, mineral wool is a fairly crude product. Consequently, it can contain a lot of "junk" elements, among them Ca, K, Na, Al, Mg, Fe, S, Cl. I don't know about barium but nothing would surprise me. Because of the elemental "ambiguity" of fibrous glass, PLM is really the way to go here.
Reference (of course): The Particle Atlas Electronic Edition.
--
Stephen A. Shaffer MicroDataware sshaffer-at-microdataware.com (business) http://www.microdataware.com (temporarily out of service) steve_shaffer-at-compuserve.com (personal) http://ourworld.compuserve.com/homepages/steve_shaffer/
We are looking for sources for rebuilt Filaments for a JEOL 5800LV SEM. Can anyone give us info on this?? (Where to get them and how much they are if possible).
Has anyone had experience with eliminating excessive amounts of dust in their EM rooms?
I moved into a newly renovated suite of rooms over a year ago. Since that time we have been plagued by dust and dirt. It has become almost impossible to maintain uncontaminated grids or negatives and prints without dust or scratches. For example you cannot leave a negative on a light box overnight because it is covered by a thin film of dust by the next day.
The Engineering department had the ductwork cleaned and higher efficiency filters installed on the fan units supplying air to the suite during renovations. They claim the supply air is the same quality as that in my previous location in another building (where excessive dust was not a problem).
An outside consultant has monitored the rooms and found particle counts between 20,000 and 50,000 in the 0.5 micron size range, per cubic foot. They recommend installing HEPA filters on all supply air ducts to reach class 1,000 conditions.
The Engineering department is reluctant to install 10 or more HEPA filter units due to the cost and the necessary ductwork reworking. They claim the supply air is clean and the filters will not solve the problem. They would like to install electrostatic particle precipitators in each room to scrub the air clean.
Does anybody have any experience with electrostatic precipitators and which type is best?
Is there a standard for airborne particles within a microscopy facility?
Is the class 1,000 condition recommended by the consultant excessive?
We are about to begin renovations for our light microscope area which will have a number of digital imaging stations in addition to film and video. What recommendations can I make to engineering in the design of the HVAC system to address this issue during construction?
Sorry for the excessive bandwidth of this message but I wanted to be as explicit as possible.
Thanks in advance for your help, Frank Macaluso **************************************************************************** Frank Macaluso tel: 718-430-3547 Analytical Imaging Facility fax: 718-430-8996 Albert Einstein College of Medicine e-mail: macaluso-at-aecom.yu.edu 1300 Morris Park Avenue Bronx, NY 10461 ****************************************************************************
} Has anyone had experience with eliminating excessive amounts of dust in } their EM rooms? }
Frank, better responses may be forthcoming from others, but one quick thought occured to me. You might ask your Engineers if the return air passes through a "plenum" above the ceiling or below the floor. This is just a fancy word for saying that the open space (above or below) acts as the return duct. If this is the case, and it often is, that might be the source of a large part of your problem. You've probably seen, or can imagine, the cleanliness of these areas! If so, regardless of filtration systems, you should probably start with a dedicated HVAC system for the microscopy rooms and incorporating duct work for both supply and return sides. Then add filtration as necessary to achieve acceptable cleanliness. It may be that, in your circumstances, Class 1000 is more than really necessary but you're probably in for some expensive retrofitting in any event.
--
Stephen A. Shaffer MicroDataware sshaffer-at-microdataware.com (business) http://www.microdataware.com (temporarily out of service) steve_shaffer-at-compuserve.com (personal) http://ourworld.compuserve.com/homepages/steve_shaffer/
Dale Callaham wrote: =================================================== I'm trying to get a prep of Scenedesmus cells onto a filter membrane for fixation, CPD, sputtering. Seems straightforward. These cells fly away from the Nucleopore (PC) or Millipore (cellulose ester) membranes when I transfer to a liquid after depositing the cells by gentle suction =================================================== While there are no guarantees, you might want to consider the following:
a) Polycarbonate "track etch" (PCTE) membrane filters, irrespective of who has made them, including the SPI-Pore(tm) membrane filters are treated with PVP (polyvinylpyrrolidone) to serve as a wetting agent, making the surface more hydrophilic and enhancing the filtration rates. We have special requests for supplying the membrane filters without PVP (for several different reasons) which can be done and apparently, in some instances, affects the way things adhere. Not wanting to be too commercial about it, it is my understanding that at least one other supplier of PCTE membrane filters can supply their products without PVP as well. In order not to mislead, there are in fact different production processes in use and not all PCTE membrane filters are identical. This is an instance where if you have tried one, you have certainly not tried them all. I am not saying this is a matter of good vs. bad, this is just a matter of membrane filters from different sources can be expected to behave "different".
b) Silver membrane filters also seem, at least in some instances, to provide better attachment possiblities than the polymer membranes. I have been intrigued as to why that is the case, but the silver membranes can be handled in a surprisingly similar way as are the polymer membrane filters, anything you can do, including critical point drying, to a polymer membrane you can do to a silver membrane. A bonus with the use of silver membrane filters is that much less metallization or no metallization is required. I have also been told that there are indications that a plasma etching ("cleaning"), presumably because of a removal of adsorbed organics, also enhanced cell adhesion.
Disclaimer: SPI offers PC and silver membrane filters as well as the a plasma etcher, details about which can be found on our website below.
Chuck =================================================== Charles A. Garber, Ph. D. Ph: 1-(610)-436-5400 President 1-(800)-2424-SPI SPI SUPPLIES FAX: 1-(610)-436-5755 PO BOX 656 e-mail: cgarber-at-2spi.com West Chester, PA 19381-0656 USA Cust. Service: spi2spi-at-2spi.com
Look for us! ############################ WWW: http://www.2spi.com ############################ ==================================================
Currently, I am searching for protocols that deal with collecting stool samples and preparing them for TEM. Does anyone have such an item? My purpose for using this protocol is to eventually isolate viral structure in patients with Acute Disseminated Encephalomyelitis.
Thank you, Debra Caires The National Encephalitis Foundation
San Jose State University Biological Sciences One Washington Square San Jose, CA 95192 =46AX (408) 298-3263
The proceedings of EUREM-11 (Dublin 1996) will shortly be published by CESM, with the full backing of IFSEM. The 3-volume set will be available for a maximum price of 400 French Francs (approx US$ 70); the exact price will depend on the number of orders received and since the books will be printed in France, the price in francs is definitive.
If you are interested, please request an order form from Peter Hawkes E-mail: hawkes -at-cict.fr or hawkes-at-cemes.fr Fax: (+33) 562 25 79 99
Be sure to give your fax number or full postal address. Please respond IMMEDIATELY as we hope to print these proceedings very soon indeed and only a limited number will be available once orders have been serviced.
Dr Peter W. Hawkes CEMES-LOE du CNRS B.P. 4347 31055 TOULOUSE cedex 4 (France)
Dear Randy, In my experience in looking at fiberglass, I would expect some Na, which is a common part of most glasses. The Ba may be from BaSO4, which is a common whitener or may also be in glass. The fiberglass fibers should be unnaturally smooth and uniform. Rock wool, which was also mentioned, is very coarse, more like 20 microns, and dark in color. You wrote: } Greetings to All, } } I've recently been handed a sample consisting of dust collected near a } suspected pollution source. The sample was picked up on cotton swabs in an } extremely non-scientific manner (off the hood of a car in the desert, and } they want to know if silicon is present---go figure), and the client is } looking for fiberglass particles, among other things. I have found fibers } in the sample about 10-12 microns in diameter which resemble SEM photos I } have seen of fiberglass. } } My question is this: What elements would one expect to find in fiberglass, } other than (obviously) silicon? I'm aware of calcium and aluminum being } used in glass, but are there other commonly used elements? Specifically, } barium? (5 distinct Ba peaks in this one!) } } The sample is on a carbon stub using carbon adhesive tape. We're using a } variable pressure SEM with 7 Pa of pressure. The EDS on the fibers is } being done in spot analysis mode at a mag of 3000x. I'm reasonably } confident that most of the signal is coming from the fiber itself, allowing } of course for beam skirting, etc. } } Thanks in advance for any advice. } } } Randy Tindall
Regards, Mary Mary Mager Electron Microscopist Metals and Materials Engineering University of British Columbia 6350 Stores Road Vancouver, B.C. V6T 1Z4 CANADA tel: 604-822-5648 fax: 604-822-3619 e-mail: mager-at-interchg.ubc.ca
Thankyou to those who replied to my query re pre-prepared Uranyl Acetate, I was asked to post replies to server and here they are. Charles Garber Presidentof SPI Supplies wrote that his company had considered pre-prepared uranyl ace- tate some years ago but found the cost to be extremely high, another suggestion was that as Reichert make an automatic grid stainer, they may be able to supply uranyl acetate in this form. Thanks again, Orla O'Shea.
I am interested in looking at tape heads used in digital data storage systems via a light interferometry system. We wish to measure parameters such as head profiles, gap widths and other issues to less than a micron resolution. To do this accurately we need to know the refractive index of the different materials in the heads. Some of them are exotic alloys which makes this difficult, and I am trying to think of alternative techniques to assist us. Coating the samples would be one idea since the light would be effectively incident upon the same material but they have a rather fiddly cross section and I am not convinced that we could coat the samples without any shadowing. Replication seemed like a good idea, apart from the resolution worries, or would we have the same shadowing problems? Does anyone have any knowledge about this?
It is not uncommon to findphosphates and borates in significantly high quantities in the fibreglass materials. As to, morphological identification anisotropy of fibres makes it easy to identify. However beware that fibres morphology may contain gas bubbles. So btoken fibres may look jagged with curved edges
At 01:44 PM 11/10/97 -0700, Christopher wrote: } We are looking for sources for rebuilt Filaments for a JEOL 5800LV SEM. } Can anyone give us info on this?? (Where to get them and how much they } are if possible).
Energy Beam Sciences has been manufacturing both new and rebuilt filaments for JEOL SEMs for more than 25 years. I will respond to the pricing question directly to Christopher and hope the other manufacturers will follow the same policy {grin}
Best regards, steven E. Slap, Vice-President ******************************** Energy Beam Sciences, Inc. Adding Brilliance To Your Vision ebs-at-ebsciences.com http://www.ebsciences.com/ ********************************
I do it rountinely in my EM lab for animal clinics.
-use a disposal pipe to pick a tiny sample and dispense in a vial containing 0.5-1 ml of 0.1% glutaraldehyde in buffer, mix the sample well and let it sits for 15-30 min.
-do negative staining as usual from the supernatant in 1-2% PTA.
Good luck.
On Mon, 10 Nov 1997, Debra J. Caires wrote:
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } Dear All, } } Currently, I am searching for protocols that deal with collecting } stool samples and preparing them for TEM. Does anyone have such an item? } My purpose for using this protocol is to eventually isolate viral structure } in patients with Acute Disseminated Encephalomyelitis. } } Thank you, } Debra Caires } The National Encephalitis Foundation } } San Jose State University } Biological Sciences } One Washington Square } San Jose, CA 95192 } FAX (408) 298-3263 } } } } }
*********************************************** * Ming H. Chen, PhD * * Medicine/Dentistry Electron Microscopy Unit * * University Of Alberta. * * Edmonton, Alberta, Canada * * * * Visit My Page At: * * http://www.ualberta.ca/~mingchen * ***********************************************
I am finding that lifetime for my FEI LaB6 cathode exceed 1000hrs, but after 100hr the gun becomes unstable (... constant tilt/shift alignments ...) to the point I have to get into the gun and clean the wehnelt, which remedies the problem. The deposits are difficult to remove and I have to resort to judicious use of diamond paste. I'd much rather find an agent which would remove these deposits over-night and not attack the SS metal. Has anyone a better idea??? ... TIA ...
cheerios, shAf -- {\/} /\ {\/} /\ {\/} /\ {\/} cogito, ergo zZOooOM {\/} /\ {\/} /\ {\/} /\ {\/} Michael Shaffer, R.A. - University of Oregon Electron Probe Facility mshaf-at-oregon.uoregon.edu -or- mshaf-at-darkwing.uoregon.edu http://darkwing.uoregon.edu/~mshaf/
Dear Sirs I am an undergraduate Physicist at King's College London. As a final year student, we are expected to complete a major laboratory project.We have come up against a problem which we feel is beyond our capabilities. In order to measure accurately the thickness of some thick films we have made, we need to interface our TEM with the P.C, via a printer board electronic circiut. We as physics undergrads are unable to write the correct syntax for the programme for the interface and would be grateful if you could help us with it. If your archive has the bit we need in "C" please e-mail it to me. If you are unable to help, thankyou anyway. Regards, Jennifer Ayriss.
} -- [ From: Garber, Charles A. * EMC.Ver #3.1 ] -- } } Your are right, the background is not going to be smooth structureless and } featureless like on a TE membrane. However, I have seen fragile features on } certain life science samples that could not survive the level of } metallization that would other wise be required. I was addressing my } comments to those kinds of situatons. } } What do you think about the belief that there is better attachment to non- } PVP treated membranes, is that possible or just an old wive's tale? } } Chuck
Hi Chuck, I can't comment on the above belief. You are the first who has mentioned it to me. I'd have to conduct an empirical comparison between treated and non-treated, I'd also include poly-L-lysine and collagen treated membranes as long as I was going to the trouble. Has any of the collective ever looked at this?
I haven't put any metal on an SEM sample in about a year, I've been doing uncoated LVFESEM with pretty decent results. Of course I'm not going up to 50,000x either. I need to be able to shuttle back and forth between SEM and TOF-SIMS instruments.
I do pre-coat some PC membranes with AuPd for conductivity prior to applying samples. Again, I don't know what adsorbtion changes may be induced. Particulate samples (yeast) are still present after freeze drying.
cheers ed
Edward J. Basgall, PhD The Pennsylvania State University Surface Chemistry Group ejb11-at-psu.edu Materials Research Institute Building Ph: 814-865-0493 University Park, PA 16802-7003 FAX: 814-863-0618 http://www.personal.psu.edu/ejb11/ Privilege does not absolve one of ecological responsibility.
} Dear All, } } Currently, I am searching for protocols that deal with collecting } stool samples and preparing them for TEM. Does anyone have such an item? } My purpose for using this protocol is to eventually isolate viral structure } in patients with Acute Disseminated Encephalomyelitis. } } Thank you, } Debra Caires } The National Encephalitis Foundation } } San Jose State University } Biological Sciences } One Washington Square } San Jose, CA 95192 } FAX (408) 298-3263 } Hi Deb, There are numerous references available on this. I did a poster on the subject at MSA in 1988, Basgall, E.J., Scherba,G., and Gelberg, H.B. "Diagnostic Virology in Veterinary Pathology: Techniques for Negative Staining." I will FAX you a copy of the abstract with references today.
good luck cheers ed
Edward J. Basgall, PhD The Pennsylvania State University Surface Chemistry Group ejb11-at-psu.edu Materials Research Institute Building Ph: 814-865-0493 University Park, PA 16802-7003 FAX: 814-863-0618 http://www.personal.psu.edu/ejb11/ Privilege does not absolve one of ecological responsibility.
At 08:14 AM 11/11/97 -0800, you wrote: } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America
} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} { GO GATORS Scott D. Whittaker 218 Carr Hall Research Assistant Gainesville, FL 32610 University Of Florida ph 352-392-1295 ICBR EM Core Lab fax 352-846-0251 sdw-at-biotech.ufl.edu http://www.biotech.ufl.edu/~emcl/ The home of " Tips & Tricks "
} } } Ed - } } Did you make the "bread" part of the sandwich yourself? A lab I } } worked in ages ago had special Millipore snap-together units to do this } } same thing; I've never been able to track them down from any vendors. i } } would like to see how you do this - the homemade sandwiches I've tried } } always loosen partway through fixation. } } } } Thanks! } } } } Tamara Howard } } CSHL } } Yes Tamara, } } I remember those snap together units. Thomas Scientific (800-345-2100) } still sells them, CAT # 4626-N20 13mm, p585 in 96-97 catalog. 10/pk list } price $30. Made from polycarbonate plastic. } } No affiliation or financial interest, yadda, yadda, yadda.... } } I will have the filter sandwich details posted to my website by Friday (11-14) } } cheers } ed } } Edward J. Basgall, PhD } The Pennsylvania State University } Surface Chemistry Group ejb11-at-psu.edu } Materials Research Institute Building Ph: 814-865-0493 } University Park, PA 16802-7003 FAX: 814-863-0618 } http://www.personal.psu.edu/ejb11/ }
} i have archived a recent discussion on this at the following URL (Tips & } Tricks site): } } http://www.biotech.ufl.edu/icbr/emcl/db/lab6crud.html } } ...
Thanx ... it appears the consensus is dilute HCl for short periods together with H2O rinses, and I can't imagine this being much of a problem for stainless steel ... but it *was* strange to see someone else suggest ammonia ... that is, base over an acid attack ... and can I assume the "soap-scum remover" suggestion is also basic. I can't imagine ammonia being a problem either, 'cept its suggested use is an over-nite bath ...
thanx again, shAf -- {\/} /\ {\/} /\ {\/} /\ {\/} cogito, ergo zZOooOM {\/} /\ {\/} /\ {\/} /\ {\/} Michael Shaffer, R.A. - University of Oregon Electron Probe Facility mshaf-at-oregon.uoregon.edu -or- mshaf-at-darkwing.uoregon.edu http://darkwing.uoregon.edu/~mshaf/
} i have archived a recent discussion on this at the following URL (Tips & } Tricks site): } } http://www.biotech.ufl.edu/icbr/emcl/db/lab6crud.html } } ...
Thanx ... it appears the consensus is dilute HCl for short periods together with H2O rinses, and I can't imagine this being much of a problem for stainless steel ... but it *was* strange to see someone else suggest ammonia ... that is, base over an acid attack ... and can I assume the "soap-scum remover" suggestion is also basic. I can't imagine ammonia being a problem either, 'cept its suggested use is an over-nite bath ...
thanx again, shAf -- {\/} /\ {\/} /\ {\/} /\ {\/} cogito, ergo zZOooOM {\/} /\ {\/} /\ {\/} /\ {\/} Michael Shaffer, R.A. - University of Oregon Electron Probe Facility mshaf-at-oregon.uoregon.edu -or- mshaf-at-darkwing.uoregon.edu http://darkwing.uoregon.edu/~mshaf/
The site listed below is an expert system for determining cleaning procedures. Great stuff. If dilute HCL doesn't work, then this web site might a good place to get direction.
http://clean.rti.org/
------------------------------------------------ Opinions or statements expressed herein, rational or otherwise, do not necessarily reflect those of my employer.
Harold J. Crossman OSRAM SYLVANIA INC. Lighting Research Center 71 Cherry Hill Dr. Beverly, MA 01915 Phone: (508) 750-1717 E-mail: crossman-at-osi.sylvania.com
Our web sites: www.sylvania.com www.siemens.com --
Another alternative you may consider still used the polish paste. Our sevice eng. taught us this one. Take a dremel and put a Q-tip in it (drill may work too) put on some paste and let her rip. We don't run lab6 so I have no experience with that aspect, just the usual crud in any biologic EM.
At 10:05 AM 11/11/97 -0800, you wrote: } Scott Whittaker wrote: } } } i have archived a recent discussion on this at the following URL (Tips & } } Tricks site): } } } } http://www.biotech.ufl.edu/icbr/emcl/db/lab6crud.html } } } } ... } } Thanx ... it appears the consensus is dilute HCl for short periods together } with H2O rinses, and I can't imagine this being much of a problem for } stainless steel ... but it *was* strange to see someone else suggest ammonia } ... that is, base over an acid attack ... and can I assume the "soap-scum } remover" suggestion is also basic. I can't imagine ammonia being a problem } either, 'cept its suggested use is an over-nite bath ... } } thanx again, shAf } -- } {\/} /\ {\/} /\ {\/} /\ {\/} cogito, ergo zZOooOM {\/} /\ {\/} /\ {\/} /\ {\/} } Michael Shaffer, R.A. - University of Oregon Electron Probe Facility } mshaf-at-oregon.uoregon.edu -or- mshaf-at-darkwing.uoregon.edu } http://darkwing.uoregon.edu/~mshaf/ } } } }
} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} { GO GATORS Scott D. Whittaker 218 Carr Hall Research Assistant Gainesville, FL 32610 University Of Florida ph 352-392-1295 ICBR EM Core Lab fax 352-846-0251 sdw-at-biotech.ufl.edu http://www.biotech.ufl.edu/~emcl/ The home of " Tips & Tricks "
} Another alternative you may consider still used the polish paste. Our } service eng. taught us this one. } Take a dremel and put a Q-tip in it (drill may work too) put on some paste and } let her rip. ...
My service rep reccommended against this as it can be quite abrasive. However, the technique is okay if you buy the variable speed dremel and use its slow speed ... saves quite a bit of elbow grease ... cheerios, shAf -- {\/} /\ {\/} /\ {\/} /\ {\/} cogito, ergo zZOooOM {\/} /\ {\/} /\ {\/} /\ {\/} Michael Shaffer, R.A. - University of Oregon Electron Probe Facility mshaf-at-oregon.uoregon.edu -or- mshaf-at-darkwing.uoregon.edu http://darkwing.uoregon.edu/~mshaf/
} Another alternative you may consider still used the polish paste. Our } sevice eng. taught us this one. } Take a dremel and put a Q-tip in it (drill may work too) put on some paste } and let her rip. We don't run lab6 so I have no experience with that } aspect, just the usual crud in any biologic EM.
Be careful if you use this technique because it can quickly enlarge and distort the aperture of the Wehnelt shield or cap. Once enlarged, the gun geometry is degraded until you replace the cap with a new one.
#################################################################### John J. Bozzola, Ph.D., Director Center for Electron Microscopy Neckers Building, Room 146 - B Wing Southern Illinois University Carbondale, IL 62901 U.S.A. Phone: 618-453-3730 Fax: 618-453-2665 Email: bozzola-at-siu.edu Web: http://www.siu.edu/departments/shops/cem.html ####################################################################
We have been using the ultrasonic bath with "Micro" cleaning solution (Catalog #6731, International Products Corp, 609-386-8770) to clean the wehnelt, apertures, etc.
I used to use the metal polish and much scrubbing with q-tips, cotton, followed by ultrsonic rinsing with isopropanol. This cleaning solution does a great job, and removes tungsten deposits that I could not previously remove.
The solution works best when warm, and I must confess that I use a stronger mix than the instructions dictate (instructions say 2%, I use about 10% or so in distilled water). I put this brew into a big glass beaker, heat it up on the hot plate, put in the parts, and immerse in the ultrasonic bath. I follow that by sonication in distilled water with a finish using isopropanol. We just did a column routine on our Jeol 733 using the solution and it also removed deposits from little crevices that were not cleaned that well before.
I have not observed any detrimental effects on the pieces we have cleaned, and am especially interested in hearing about it if it does happen.
The solution smells of ammonia but the ingredients show more than that.
I think I paid about $10 for 1 quart. Highly recommended.
Paul Carpenter
+----------------------------------------------------+ | Paul K. Carpenter paulc-at-gps.caltech.edu | | Division Analytical Facility | | Geological and Planetary Sciences MC 100-23 | | California Institute of Technology | | 1200 East California Blvd | | Pasadena, CA 91125 | | 626-395-6126 (X-ray Lab) 626-568-0935 (Dept. FAX) | +----------------------------------------------------+
Ciara: If you can rotate the specimen during C evaporation rather complex specimens can be coated with no 'shadows' remaining. The replication technique too should work. Plastic replicas can cope with difficult shapes too and they are quite easy to produce. A basic outline of the process is given under 'replication' (see index or "V" page) in our online catalogue. Replicating materials and instructions are provided by us and I expect all other EM suppliers. You would probably later angle shadow the replica with metal to show depths. With a known angle you can estimate height and the incorporation of latex spheres would provide an internal scale. Plastic replicas are accurate to better than 0.1um. Jim Darley
ProSciTech Microscopy PLUS PO Box 111, Thuringowa QLD 4817 Australia Phone +61 77 740 370 Fax: +61 77 892 313 Great microscopy catalogue, 500 Links, MSDS, User Notes ************************ http://www.proscitech.com.au
---------- } Hello } } I am interested in looking at tape heads used in digital data storage systems } via a light interferometry system. We wish to measure parameters such as head } profiles, gap widths and other issues to less than a micron resolution. To do } this accurately we need to know the refractive index of the different materials } in the heads. Some of them are exotic alloys which makes this difficult, and I } am trying to think of alternative techniques to assist us. Coating the samples } would be one idea since the light would be effectively incident upon the same } material but they have a rather fiddly cross section and I am not convinced that } we could coat the samples without any shadowing. Replication seemed like a } good idea, apart from the resolution worries, or would we have the same } shadowing problems? Does anyone have any knowledge about this? } } } Thanks in advance } } Ciara } } } } *********** *********** Dr C A Mullan } ******** / ******** Computer Peripherals Bristol, } ****** /__ __ ****** Hewlett-Packard Ltd, } ***** / / / / ***** Filton Road, Stoke Gifford, } ***** / / /__/ ***** Bristol, England. BS12 6QZ } ****** / ****** } ******** / ******** } *********** *********** } Tel: +44 (0) 117 922 9908 } Fax: +44 (0) 117 923 6091 } } } }
Be careful of electrostatic precipitators. They may produce low concentrations of ozone and contribute to rapid deterioration of rubber parts of equipment. Best test is the lifetime of a stretched rubber band; compare to control prep'n perhaps at home.
Air-conditioner type filters treated with a polyethylene glycol spray may stop the dirt to a great extent without going to the expense of HEPA filters. Under the conditions you describe, the initial cost might not be as big a burden as the cost of frequent replacements!
San Francisco Microscopical Society November Meeting Announcement
Annual Swap Meet November 15, 1997 =
=
Place: Rockridge Branch Oakland Public Library 5366 College Avenue Oakland CA
Time: 10:00 A.M.
Everyone has old microscope parts, equipment, supplies, and associated items that they would like to get rid of =96 and all microscopists have room in the microscopical cabinets for that perfect gizmo that the next persons wants to be rid of. This is your opportunity to get rid of those things you don=92t want any more, and replace them with those invaluable items that other people will bring.
Bring all of you tradeables to the meeting on Saturday and see what you can get rid off, and see what you can take home with you.
For further information, you may contact Peter Barnett at 510-222-8883 or visit the SFMS Meeting Web Page at: http://ourworld.compuserve.com/homepages/steve_shaffer/announce.htm The web page contains further information, maps, directions via car and public transportation, etc.
-- =
Stephen A. Shaffer MicroDataware sshaffer-at-microdataware.com (business) http://www.microdataware.com (temporarily out of service) steve_shaffer-at-compuserve.com (personal) http://ourworld.compuserve.com/homepages/steve_shaffer/
For those interested, the authors and titles of presentations to be given at the Microscopy Society of Southern Africa's 37th Annual Conference is available at:
http://www.uct.ac.za/depts/emu/mssa/contents.htm
Abstracts of these presentations are published in the conference proceedings.
The conference will take place from December 2 to 5, 1997, at the University of the Western Cape in Bellville, near Cape Town.
Robin H Cross Director : EM Unit, Rhodes University, Grahamstown, South Africa eurc-at-giraffe.ru.ac.za - tel: +27 461 318168 - fax: +27 461 24377
I am looking for a human pan-keratin antibody to recognise both epidermal and hair keratinocites. Can somebody suggest me a good, possible, policlonal antibody?
Dr. Cristiano Rumio Istitute of Human Anatomy Via Mangiagalli 31 20133 Milan Italy Tel. -39-2-2663683 Fax. -39-2-2364082 E-mail: crylsm-at-imiucca.csi.unimi.it URL: http://imiucca.csi.unimi.it/~endomi/confocal.html __________________________________________________________________________
I am busy with a literature study on STM/AFM and epitaxial grown Au layers. I have a few questions on using gold substrates in STM/AFM.
1. If you use gold evaporated onto mica as a substrate, do you need to separate the gold and mica before you can use the atomically flat gold as a substrate? Or do you stick it ont some kind of stub for the STM? 2. Is there a minimum/maximum thickness of gold foils suitable for substrates? 3. If you want to use atomically flat gold as substrate, do you buy it or make it yourself (and to all the vendors, I'm not interested in buying, just asking...).
Disclamer: I am NOT a vendor, I sell nothing (except perhaps my soul), I have done my best to come up with reasonable current market pricing in all the following comparisons and this is a LONG email.
Yes, high resolution images (which maintain their resolution, i.e. not subjected to 'losey-compresion') do take up alot of storage space - as my students are constantly shocked at. Storage of these images is problematic, and presently there is no ideal soloution, but here are some for consideration:
Definitions: Mb= Megabit (Divide by 8 to get MB), MB = MegaByte, GB=Gigabyte, 1000MB = 1GB (Hey some of us are really just starting out) and $ = U.S.D.
In order to make some sense in comparison I have choosen the simplistic view in regards to data transfer rates (i.e. the speed for transfering data between the storage device and the computer system/software) and simply have relied on manufacturers reported transfer rates. Things to keep in mind with these numbers (1) you'll never see these speeds in reality - they are all determined in ideal situations not real world usage, but they are comparable with each other; (2) Actual transfer rates will vary depending on the interface used (i.e. the max. throughputs for the interfaces are EIDE (1-10MB/sec) vs SCSI (5-10MB/sec) vs SCSI-Wide (20MB/Sec) vs SCSI-UltraWide (40MB/Sec) vs parallel ports ( {1 vs Fiber Coupling (a.k.a. Fire Wire, 100+MB/Sec), (3) System configuration will also effect this; i.e. what CPU, what BUS speed, how much memory (RAM) what other components are in the system, what operating system, etc. , (4) the biggest factor in the data transfer numbers game is "Maximum Burst" transfer speed vs "Throughput speed". My only hope in presenting this information is that is gives you a starting point for comparisons.
1) Zip drives are cheap ($140 for drive) but cartridges are expensive ($13 / 100MB - I'll use 100MB as the standard unit for price comparison). 100MB is not very much storage capacity, and the transfer speeds are very slow -at- 1MB/Sec NOTE: unless you have min. 650MB free HD space you can NOT record an entire CD directly (On -The-Fly) from a a zip drive, you'll have to record in multisession mode (and lose 13MB in "overhead" for each session after the first one, i.e. a 640MB CD-R would require 6 Sessions thus loosing 65 MB).
2) Iomega JAZ drives: $300/400 (Int/Ext) with 6.73MB/sec transfer, 1GB cartridge-at-$124 [$12/100MB] (Expensive AND slow!)
3) Don't be so quick to reject tape storage. Tape storage can be extremely cost effective in larger formats, speed can be a problem but going back to older work-around solutions, users wishing to work on files on Tuesday could transfer the data from tape to HD Monday night, and then transfer back - alternately, utilizing a file server for this task (File Server: HD's, Tape drives, CD-drives for handleing just data storage: reading and writing only, no running of other software) would free up workstations for computational work. Yes, random access is limited but if you're looking at serial section reconstruction you'll be accessing sequentially anyway. CON: You have to a have a drive to read and write the data (unlike ubiquitous CD-ROM readers).
Drives go upto the following: 20-40GB, 32-64GB, 70-150GB, 100-200GB, 140-280GB -at- $2,000-9,000.
NEW Iomega Ditto Max drives: upto 7GB* drives -at- $200, upto 10GB* drives -at- $300, (*these are compressed data values, compression will slow down transfer speeds) with transfer speeds upto 36MB/sec and tapes running $20/3gb - $35/10GB [$0.20-$0.30/100MB].
4) CD-ROM storage: This makes alot of sense, since 99% of all computers come with CD-ROM readers. If you (or your users) have older CD-ROM readers, then they will need to cough up $80-150 to buy a newer one (10x IDE drive - 16x SCSI). For comparison sake a 1x refers to the standard speed of an Audio CD and allows for 150kilbytes of data transfered per second. Therefore a 10x CD-ROM would allow for upto 1.5MB/second transfer. Actual transfer rates will vary depending on the interface used (i.e. IDE vs SCSI, etc.).
CD-Recorders (CD-R's): these vary ALOT in recording speeds (1x-4x -6x?) and prices follow ($340 - $800), plus you'll need recording software ($50-100), and its recommended that you have a dedicated temporary storage drive for the higher recording speeds ($180-500). CD-R's are sensitive to recording errors, but they have become much more routinely reliable in the last 1-2years (particularly with a dedicated temp storage disk). CD-R's are WORM disks (Write Once Read Many), that means if you record practice images, you can't erase them and re-use the space. However, the recording media is reasonably cheap -at- 3.50-5.00/640MB disk [$0.54-0.78/100MB].
CD-ReWriteables (CD-RW): These are new to market as of this spring they do allow for re-writing to the media. There are still only a few manufactures and they record at 1-2x presently and cost ~$500. The media is also very expensive ($25/disk) but is expected to drop too reasonable prices by early next year. However! CD-RW's apparently can only be read in CD-RW drives and NOT normal CD-ROM drives. Ricoh does offer a drive which fuctions as CD-ROM, CD-R, and CD-CW (MediaMaster ~$550).
5) DVD anyone? (and NO "DVD" is not a an anacronym, it once was but had three different definitions so the powers that be decided to just leave it as DVD). This ones easy: NOT READY FOR PRIME TIME YET. Currently readers only are available, and recorders MIGHT be come available late 1998, however the major manufactiring groups have had a falling out again after coming up with a "standard" recording format, and there are two incompatible (?) formats heading our way so it might be until 1999-2000 before this becomes a reality and affordable. However, it may offer the best solution to todays image storage problems, in that the DVD storage capacity is 4.7GB for single sided and 7GB for double sided. But we shall see, eh?
6) Optical Drives: Currently available optical dirves are ReWritable (there are still some WORM drives though) fall into two major categories: Mageneto-Optical (MO) drives and PD Drives. MO drives come in various sizes from 128MB upto 4.6GB, I would suggest that only drive 640MB and larger be considered. PD drives come in 640-650MB sizes, these sizes are very nice because they match the CD-R size. Therefore you could use the MO or PD for temporary storage and then archive to CD-R. However, once again you need to have a drive to read these MO or PD's as well as write them. Most of the drives will handle the next 2 or 3 sizes smaller capacity disks, i.e. the 2.6GB MO's will read/write 1.3 & 650 disks. Prices are as follows (Internal/External):
4.6GB, $1,450/1,550, disks -at- $99 [$2.15/100MB] [MediaStore has the Mitsubishi 4200 4.6GB on sale for $999! 4.2MB/sec transfer]
640/650 PD drives: $350/440, disk -at- $34 [$5.20/100MB]
Toray has a 650 PD, 900kilobyte/sec which is also a CD-ROM reader for $315/405.
7) Removable hard disk frames: Another alternative, one which has been choosen by Hollywood (See Advanced Imaging October 1997, P.74) is the usage of removable harddrives. Frames for making HD's removable run: $20:IDE; $30:SCSI; $70:SCSI-Wide. However this does not include the cost of the drive (obviously). Secondly, HD's are delicate instruments and care must be taken when moving them about, but a rack close to a user accessible computer system (say one with a CD-Recorder?) would be a useful solution for the highest speed data transfer. 2-6GB IDE's -at- $7-5/100MB, 2-10GB SCSI -at- $7-10/100MB, 2-23GB SCSI Ultra-Wides -at- $7-20/100MB (On all HD's Bigger drives have lowest costs per MB).
There are a few other, less common solutions, and each faclity will need to develope their own prefered solution. However, I'm sure there are a number of vendors out there who'd love to sell you a turn-key system package for $20-40k.
Richard E. Edelmann, Ph.D. Electron Microscopy Facility Supervisor 352 Pearson Hall Miami University, Oxford, OH 45056 Ph: 513.529.5712 Fax: 513.529.4243 E-mail: edelmare-at-muohio.edu
"640K ought to be enough for anybody." -- Bill Gates, 1981
Daraporn, I think the answer is no. I am assuming that you took a diffraction pattern with the probe focused on the sample (i.e. you have a BF CBED disk). In this case, you have only measured the convergence angle of the probe. If you had an infinitely small source, knew you were in focus and fully stigmated, and knew the Cs of the probe forming lens, you could determine the theoretic probe size. But, for a non-FEG TEM, the probe size is mainly determined by the demagnification of the finite source (i.e. the spot size selected). You might be able to go back and image probe under similar conditions to get an approximate value for the probe.
Hope this helps, -- Ray D. Twesten Center For Microanalysis of Materials (217) 244-6177 University of Illinois (217) 244-2278 (fax) 104 S. Goodwin Ave. (217) 359-4035 (home) Urbana, IL 61801
Daraporn Arayasantiparb wrote: } } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } Dear All, } } I have a question maybe someone could help me... I want to measure } the size of my probe, but I collected the wrong image... i.e., I collected } the image of the probe in the diffraction mode... Is it possible to find } actual size of the probe? I think if I know the distance between the } objective aperture and the selected area aperture and the point of } convergence of the convergence angle, I should be able to calculate it } from there... but where can I find all these information?... Can anyone } help me? } } Your suggestions is greatly appreciated. } } Sincerely, } Daraporn Arayasantiparb
You say that an outside consultant reports that your EM room averages 20K - 50K particles in the 0.5 micron range per cubic foot. From experience, I would be surprised if you get a visible film of dust observed on a light background overnight, but perhaps a visible film of dust on a dark shiny negative as you describe sounds reasonable, especially when viewed by scattered light. You definitely shouldn't get anything you can feel with your fingers overnight.
I recommend the article "Particulate Fallout Predictions for Clean Rooms" by Otto Hamburg in The Jour. of Environmental Sciences, May/June 1982 pp.15-20.
You can set out "witness plates" for various lengths of time and observe the amount of fallout you get and compare these results with environments of different load suspensions. Your witness plates should be identical to the substrates of interest....TEM grids and negatives, and be in the same place in your room. This can make a big difference. Particulate characteristics, air flow, humidity, substrates, etc. will be different from one person's environment to another's, meaning you cannot readily expect one person's experiences to be applicable to yours.
We have a particle prep lab that ranges between 1K-50K particles } = 0.5 micron per cubic foot, depending where you are and what phase the moon is in. We then have { Class 10 areas embedded within that where samples may be exposed to air. (Assuming that my laser counter's calibration is still good). Within the 20-50K areas that would be somewhat similar to yours, I would not expect to find significant dust accumulation on negatives overnight. However, I would guess that if the air was very dry, and there was plenty of air flow across the negatives, perhaps they would electrostatically collect enough by the next day to be a problem. I would not leave TEM grids out in this air if I was concerned about contamination.
Typical unfiltered office and home air where there is no smoke has about a few billion particles } = 0.5 microns per cubic foot. So if you have a rough idea of how rapidly dust accumulates there, you can apply the rules of 10 to get a VERY ROUGH idea of what you would get in the same environment if it had a few orders of magnitude less particulate. Again, I repeat, very rough.
I also have a story. I once worked in a cleanroom that had about 10,000 particles } = 0.5 micron per cubic foot in most areas (Class 10,000), and some Class 10 areas. About once every several days, I would find an enormous amount of dust on everything in the Class 10,000 areas and the clean room would have to be thoroughly cleaned. It appeared to be caused by "burps" in the plenum structure, caused by momentary pressure differentials, that allowed dust that had accumulated there to burp through seams in the ceiling. Solution: seal the seams. So your average dust suspension measurements may not reflect momentary, but significant, surges, for whatever reason.
Other useful references are:
FED-STD-209E Federal Standard for Clean Room and Work Station Requirements for Controlled Environments
MIL-STD 1246 Military Standard for Product Cleanliness Levels
Hope this helps.
Cynthia J. Zeissler Physical Scientist National Institute of Standards and Technology cynthia.zeissler-at-nist.gov 301-975-3910
Dear Frank, } } Has anyone had experience with eliminating excessive amounts of dust in } their EM rooms? } } I moved into a newly renovated suite of rooms over a year ago. Since that } time we have been plagued by dust and dirt. } Since you are now experiencing a problem, the simplest thing would be to put something like cheesecloth (Optic-wipe cloth works for us) over the AC input & return ports. This will cut down on the air flow, but will remove a lot of particles. If this works, there may be no need for more expensive remedies, and the worst case will be insufficient improvement. } } Does anybody have any experience with electrostatic precipitators and which } type is best? } My father had a dust allergy, and we had a precipitator in his room. They are very efficient at removing particles, but the air has to flow through the plates, so in your case they would have to be installed in the AC inputs. (It's different conditions when the particles are continuously introduced than when they are stirred up off the floor.) Furthermore, the ozone production already mentioned is a problem; activated charcoal filters after the precipitators could solve it. If you go this route, there will have to be regular maintenance of both the precipitators & the filters. Good luck. Yours, Bill Tivol
Richard E. Edelmann, Ph.D. wrote: } } 4) CD-ROM storage: This makes alot of sense, since 99% of all } computers come with CD-ROM readers. If you (or your users) have } older CD-ROM readers, then they will need to cough up $80-150 to buy } a newer one (10x IDE drive - 16x SCSI). } I don't get why users would have to buy a 10x IDE or 16x SCSI drive. Can't the CD's be written in a standard format that can be read at any speed?? I am about to buy a CD writer and apparently have missed something here. TIA, Tom
Thomas E. Phillips, Ph.D. Associate Professor of Biological Sciences Director, Molecular Cytology Core Facility 3 Tucker Hall University of Missouri Columbia, MO 65211 (573)-882-4712 (voice) (573)-882-0123 (fax)
You say that an outside consultant reports that your EM room averages 20K - 50K particles in the 0.5 micron range per cubic foot. From experience, I would be surprised if you get a visible film of dust observed on a light background overnight, but perhaps a visible film of dust on a dark shiny negative as you describe sounds reasonable, especially when viewed by scattered light. You definitely shouldn't get anything you can feel with your fingers overnight.
I recommend the article "Particulate Fallout Predictions for Clean Rooms" by Otto Hamburg in The Jour. of Environmental Sciences, May/June 1982 pp.15-20.
You can set out "witness plates" for various lengths of time and observe the amount of fallout you get and compare these results with environments of different load suspensions. Your witness plates should be identical to the substrates of interest....TEM grids and negatives, and be in the same place in your room. This can make a big difference. Particulate characteristics, air flow, humidity, substrates, etc. will be different from one person's environment to another's, meaning you cannot readily expect one person's experiences to be applicable to yours.
We have a particle prep lab that ranges between 1K-50K particles } = 0.5 micron per cubic foot, depending where you are and what phase the moon is in. We then have { Class 10 areas embedded within that where samples may be exposed to air. (Assuming that my laser counter's calibration is still good). Within the 20-50K areas that would be somewhat similar to yours, I would not expect to find significant dust accumulation on negatives overnight. However, I would guess that if the air was very dry, and there was plenty of air flow across the negatives, perhaps they would electrostatically collect enough by the next day to be a problem. I would not leave TEM grids out in this air if I was concerned about contamination.
Typical unfiltered office and home air where there is no smoke has about a few billion particles } = 0.5 microns per cubic foot. So if you have a rough idea of how rapidly dust accumulates there, you can apply the rules of 10 to get a VERY ROUGH idea of what you would get in the same environment if it had a few orders of magnitude less particulate. Again, I repeat, very rough.
I also have a story. I once worked in a cleanroom that had about 10,000 particles } = 0.5 micron per cubic foot in most areas (Class 10,000), and some Class 10 areas. About once every several days, I would find an enormous amount of dust on everything in the Class 10,000 areas and the clean room would have to be thoroughly cleaned. It appeared to be caused by "burps" in the plenum structure, caused by momentary pressure differentials, that allowed dust that had accumulated there to burp through seams in the ceiling. Solution: seal the seams. So your average dust suspension measurements may not reflect momentary, but significant, surges, for whatever reason.
Other useful references are:
FED-STD-209E Federal Standard for Clean Room and Work Station Requirements for Controlled Environments
MIL-STD 1246 Military Standard for Product Cleanliness Levels
Hope this helps.
Cynthia J. Zeissler Physical Scientist National Institute of Standards and Technology cynthia.zeissler-at-nist.gov 301-975-3910
A student will be assessing the penetration of various adhesive consolidants into egg tempera based paint layers. The consolidants would likely include animal glue, cellulosic ethers, and acrylics.
She has considered tagging the consolidant with one or more dyes to allow visual microscopic examination of depth penetration in samples cut in cross-section. Another means of assessing penetration would be micro-FTIR step-scan analysis of bulk cross-sections or thin-sections (1-5 microns).
Here's a question for the TEM folk on the list. Can anyone think of a feasible way to dope the consolidants with a metal(s) to allow mapping of depth penetration by SEM-EDS, TEM, or another technique?
I have only a limited knowledge of the use of metal-labelled antibodies to mark specific antigens using EM, and know this application I describe is quite different.
} Richard E. Edelmann, Ph.D. wrote: } } } } 4) CD-ROM storage: This makes alot of sense, since 99% of all } } computers come with CD-ROM readers. If you (or your users) have } } older CD-ROM readers, then they will need to cough up $80-150 to buy } } a newer one (10x IDE drive - 16x SCSI). } } } I don't get why users would have to buy a 10x IDE or 16x SCSI drive. Can't } the CD's be written in a standard format that can be read at any speed?? I } am about to buy a CD writer and apparently have missed something here. } TIA, Tom
I think Richard was saying that it may be worth the $100 or so necessary to upgrade the older 1X to 4X units to the faster speeds. I worked with a 1X for a few years. It was better than nothing, but it was slow!
Now a question for Richard. Do the tape drives really achieve 20 MB/sec or did you mean 20 MB/min? Our Ditto 2GB is on a flopy port and is doing well if it does 10 MB/min. ---------------------------------------------------- Warren E. Straszheim 23 Town Engineering Iowa State University Ames IA, 50011 Phone: 515-294-8187 FAX: 515-294-8216
Several of the members in the past have asked questions about Instrument rates and personal salaries. I recently saw a breakdown done on Mass Spectrometers. The breakdown was by three sectors - Industry, Government, and Universities. The data was presented for each instrument in each of the three sectors. The data was summarized including rates, the average age of the instruments and the staff to instrument ratio. Our lab was below the mean for most of the categories and now much effort is being place in trying to remedy the situation. With any luck we will acquire a new Mass Spec. and a staff member.
I was wondering if someone had a breakdown of this information handy on Microscopes and their support personal. I would like to see if we could do the same for the microscopy portion of the lab.
Thanks
Mike
=========================================================== Michael Dunlap lab (530) 752-0284 Facility For Advanced Instrumentation fax (530) 752-4412 University of California mrdunlap-at-ucdavis.edu Davis CA, 95616 http://carbon.ucdavis.edu ============================================================
We are in the process of preparing an article for the next "Focus on Microscopy" column for American Lab and would like your input. If you have 1. suggestions for image format or procedures for transporting images via the Internet or intranets, 2. tips and hints for using the inter/intranets for image libraries 3. tips and hints for communicating ideas on inter/intranets 4. microscopy or imaging Internet sites which you really enjoy please email me. If we can quote you, please add a line which gives us permission to use your name and your institution. If you have an extra minute or two, jot down a few comments about the type of work you do and what impact electronic media such as the Internet and/or intranets have had on your work.
Thanks! Barbara Foster Contributing editor American Laboratory
Ray Twesten says, in his response to Daraporn Arayasantiparb, that:
"...for a non-FEG TEM, the probe size is mainly determined by the demagnification of the finite source (i.e. the spot size selected). "
A few years ago I was involved in some work with a colleague where we made this assumption and generated some peculiar data. In the end we concluded that the probe size was, in fact, determined by the Cs of the objective lens and the convergence of the probe was too large. Depending upon where the collector aperture is placed, the convergence angle either increases or stays constant with increasing demagnification (i.e. smaller spot size settings). In our case, the probe size was in fact independant of the setting of the spot size control! (at least for the smaller sizes). It is essential to select an appropriate condenser aperture which matches the spot size setting, if that control is to have any meaning.
Tony Garratt-Reed
Anthony J. Garratt-Reed MIT Room 13-1027 77 Massachusetts Avenue Cambridge, MA 02139-4307 United States of America
Is there anyone out there that currently does particle size analysis by both Microscopy and Laser/Light Scattering techniques that can tell me if there is a listserver or newsgroup that deals with PSA specifically?
Dear all, Sorry if this has been discussed on the list before BUT.......
Does anyone know of a good method for Osmium Vapour staining/Osmium droplet staining for immuno-labelled grids? I am currently working on labelling some brain material from a honey bee, and have good signal, however I need to enhance the membranes a little more to accurately localise the labelling, than conventional staing with UA and Pb gives. Fixation is good and the tissue has been processed into Lowicryl K4M by PLT.
Like an inquisitive technician, I tried staining some Lowicryl sections of this tissue on some drops of OsO4 (with rinses afterwards) but came away with lots of tiny ppts all over the tissue! (non-specific ppts too! :-) )
So if someone could enlighten me with some trusty methods/references, that would be great!
Look forward to hearing from you,
Rich.
----------------------------------------------------------------------- Richard Lander Electron Microscope Technician South Campus Electron Microscope Unit Otago School of Medical Sciences P.O. Box 913 Dunedin New Zealand. Tel. National 03 479 7301 Fax. National 03 479 7254
"Southernmost EM Unit in the World!" ------------------------------------------------------------------------
Do any of you Reichert afficianados out there happen to know where= I can obtain a drive belt for an OmU2? I called Leica and they told= me parts are no longer available: This of course was after they= got over the shock of hearing one of these babies hasn't been turned= into a boat anchor yet. This little darling cuts like a hot knife= through butter, at least it did before the belt self-destructed= so I'd hate to see it go just because the belt is finished. If anyone= knows where I might be able to get a new belt, say for example when= you got that new Ultracut and left the OmU2 parts in that back drawer,= or make a replacement part of susbtitute goods (such as rubber bands,= duct tape, etc) I'd really like to hear from you.
Thanks a lot!
************************************************************ Everyone has a photographic memory. Some don't have film. ************************************************************ Laura Rhoads Electron Microscopy Facility Director Department of Biology Western Kentucky University 1 Big Red Way Bowling Green, KY 42101-3576
It is my experience that CDs written with our HP 4020 drive cannot be read on 1X CD readers. I have even encountered some 2X drives that don't like the written discs. (Discs are written at 1x speed.) We have 2 writers and the same holds true for CDs written by either drive. Never had a problem with a 4X or higher reader.
Bob Holthausen Pall Corporation Port Washington, NY
I think Richard was saying that it may be worth the $100 or so necessary to upgrade the older 1X to 4X units to the faster speeds. I worked with a 1X for a few years. It was better than nothing, but it was slow! Now a question for Richard. Do the tape drives really achieve 20 MB/sec or did you mean 20 MB/min? Our Ditto 2GB is on a flopy port and is doing well if it does 10 MB/min. ---------------------------------------------------- Warren E. Straszheim 23 Town Engineering Iowa State University Ames IA, 50011 Phone: 515-294-8187 FAX: 515-294-8216 E-Mail: wesaia-at-iastate.edu (or: wes-at-ameslab.gov) http://www.marl.iastate.edu/marl/ (re: SEM) http://www.public.iastate.edu/~iprt_info/cfce/ (re: coal) electron microscopy, x-ray analysis, image analysis, computer applications
wesaia-at-iastate.edu on 11/12/97 12:22:56 PM
To: Microscopy-at-Sparc5.Microscopy.Com cc: (bcc: Bob Holthausen/SLSNY/Pall/US)
At 08:56 AM 11/12/97 -0500, edelmare-at-casmail.muohio.edu wrote: } 3) Don't be so quick to reject tape storage. Tape storage can be } extremely cost effective in larger formats, speed can be a problem } but going back to older work-around solutions, users wishing to work } on files on Tuesday could transfer the data from tape to HD Monday } night, and then transfer back - alternately, utilizing a file server } for this task (File Server: HD's, Tape drives, CD-drives for } handleing just data storage: reading and writing only, no running of } other software) would free up workstations for computational work. } Yes, random access is limited but if you're looking at serial section } reconstruction you'll be accessing sequentially anyway. CON: You } have to a have a drive to read and write the data (unlike ubiquitous } CD-ROM readers). } } Some general tech specs: } } 2GB drives ($600), 11MB/sec, tapes -at- $10 [ $0.50/100MB] } } 2-4GB drives ($350-600), 29-42MB/sec, tapes -at- $31-10 } [$1.50-0.25/100MB] NOTE: Cheaper drives + More $ tapes } } 4-8GB drives ($750-1,200), 32-66MB/sec, Tapes -at- $16-28 [$0.40 } - 0.22/100 MB] } } 7-14GB drives ($700-1,600), 60-120MB/sec, tapes -at- $16 [$0.22 - } 0.11/100MB] } } 12-24GB drives ($1,000-1,300), 120-132MB/sec, tapes -at- $32-42 [$0.35 - } 0.13/100MB] } } Drives go upto the following: 20-40GB, 32-64GB, 70-150GB, 100-200GB, } 140-280GB -at- $2,000-9,000. } } NEW Iomega Ditto Max drives: upto 7GB* drives -at- $200, upto 10GB* } drives -at- $300, (*these are compressed data values, compression will } slow down transfer speeds) with transfer speeds upto 36MB/sec and } tapes running $20/3gb - $35/10GB [$0.20-$0.30/100MB].
I think you may have misquoted the above tape speeds. Based on my experience, it is more likely that the above speeds are in MB/minute instead of MB/second. That would place typical tape-drive speed more in line with that of the Zip-drive. Also, most tape-drive software accesses the tape in a sequential fashion, not randomly like the other media. This means when you wish to relocate a particular file, it will take a lot longer to get it from tape than from conventional media.
Jeff Ingeman Development Engineer Department of Anatomy & Neurobiology Department of Physiology & Biophysics University of California - Irvine (714) 824-7536 jingeman-at-uci.edu jingeman-at-aol.com jingeman-at-yahoo.com
Does anyone know if a TEM negative carrier is available for the Polaroid Sprintscan 45 Negative Scanner yet? Anyone having any experience with the carrier (if it exists) and this scanner, could you send me a little message on what you think of the system?
Thanks.
-Scott Walck
Walck-at-PPG.com
Scott D. Walck PPG Industries, Inc. Guys Run Rd. (packages) P.O. Box 11472 (letters) Pittsburgh, PA 15238-0472
(412) 820-8651 (office) (412) 820-8161 (fax)
"The opinions expressed are those of S.D. Walck and not of PPG Industries, Inc. nor of any PPG-associated companies."
} Do any of you Reichert afficianados out there happen to know where I can } obtain a drive belt for an OmU2? I called Leica and they told me parts are } no longer available: This of course was after they got over the shock of } hearing one of these babies hasn't been turned into a boat anchor yet. } This little darling cuts like a hot knife through butter, at least it did } before the belt self-destructed so I'd hate to see it go just because the } belt is finished. If anyone knows where I might be able to get a new belt, } say for example when you got that new Ultracut and left the OmU2 parts in } that back drawer, or make a replacement part of susbtitute goods (such as } rubber bands, duct tape, etc) I'd really like to hear from you.
Hi Laura,
We also have a Reichert OmU2 that we loaned out to another department. It still is operating. We did replace the drive belt (and even the shock absorbing motor mounts) before we loaned the instrument out. (Yes, it worked fine after our repair.) If I recall properly, the drive belt from the motor to the microtome is really just a large O-ring and we found one at a truck bearings repair place. So, take the belt to your local hardware store or contact an O-ring supplier (I can give you the address if you need one). You should also be aware that there is an O-ring kit available to make any size O-ring by simply cutting the stock to desired length and gluding the ends together. They do work well.
#################################################################### John J. Bozzola, Ph.D., Director Center for Electron Microscopy Neckers Building, Room 146 - B Wing Southern Illinois University Carbondale, IL 62901 U.S.A. Phone: 618-453-3730 Fax: 618-453-2665 Email: bozzola-at-siu.edu Web: http://www.siu.edu/departments/shops/cem.html ####################################################################
Hello Richard...we also had some problems with inadequate contrast of K4M embedded tissue which had been immunolabeled. Our solution was to stand the grids up on edge (in a slot cut into a wax sheet), to put the grids with the wax in a petri dish, then to add a few drops of OsO4 (2% aqueous) before covering the petri. We found that the osmium vapors imparted good contrast after about 30 minutes at room temperature.
Good luck!
Doug Keene Shriners Hospital for Children ---------------------- Doug Keene DRK-at-shcc.org
See Hayat & Miller, Negative Staining, McGraw-Hill, 1990.
Doane & Anderson, Electron Microscopy in Diagnostic Virology, Cambridge U Press, 1987.
Miller, J EM Technique (now Microsc Res & Tech) 4:265-301, 1986.
Tyrrell & Kapikian, Virus Infections of the Gastrointestinal Tract, Marcel Dekker, 1982.
I would NOT, I repeat ***NOT*** recommend fixing any virus sample before attaching it to the grid. If you are concerned with pathogenicity, you can fix it after allowing it to adhere to the grid, then wash with water and stain, or you can UV both sides of the grid after staining. For speed in reporting clinical results (we do almost 1000/year), we look at negative stains of potentially infectious material without fixing by keeping a separate specimen holder for "dirty' grids and another for nonpathogenic material such as sections. The grids are then UV'ed before storage.
Anything fixed by aldehydes, especially glutaraldehyde becomes less sticky after fixation. The most important reason that viruses in a clinical sample should not be fixed before gridding is that you decrease the numbers that stick to the support film. If you are close to the threshold of detection, you may decrease the numbers below that level.
Many of the described methods for fixing viruses before gridding include ultracentrifugation to concentrate them. This may be fine for samples such as stool from gastroenteritis patients where there are likely to be lots of virus, but for cerebrospinal fluid and other liquid samples, likely to have few viruses, you don't want to take the chance of losing any. If I were looking for an unknown virus in any sample, not knowing beforehand whether it were positive or negative, I would not want to lower my chances of finding something.
Further, adding fix to a dirty sample like stool can glue contaminants together. You can form large clumps that trap viruses and then are pelleted out in a low speed spin, effectively decreasing the number to see on your grid. Also, junk can be glued to viruses coating them so that they're unrecognizable.
It has been reported that some viruses have altered morphology after fixation. If you are looking for a novel virus, you should look at fixed and unfixed virus.
Misc. facts: We use uranyl acetate which fixes and preserves viral structure; it does NOT kill all viruses, but we use it because PTA is known to destroy some viruses, particularly reo- and rotaviruses. While you can observe them immediately after PTA staining, if you want to store them to show the prof or the medical student tomorrow or next week, you have to fix them and then wash with water before staining--adding more steps. Uranyl acetate is radioactive. PTA stains the spikes on viruses better (e.g., paramyxoviruses).
NOTE WELL: Finally, looking in stool for a virus that may be in brain may or may not yield positive results. If your question is "Does the patient who has viral encephalitis also shed virus in stool," then your search is valid. If your question is "Does the patient who has encephalitis have viral encephalitis," then you can't be sure a negative result from stool examination is valid. Not all viruses that cause viral encephalitis are shed in stool. Some never are; some are shed only for a short window of time. Some viruses that cause encephalitis could not be identified in stool, even if they were shed (e.g., alphaviruses, flaviviruses, bunyaviruses). Stool is just too dirty; there are too many membranes and vesicles that resemble viruses, and these viruses don't have a morphologically recognizable nucleocapsid. Finally some viruses cause a post infectious encephalomyelitis which appears to have an autoimmune component, and little or no virus is seen--even in brain. The only viruses you're really likely to see in feces of encephalitis patients are Picornaviruses (e.g., enteroviruses, Coxsackie viruses).
Feel free to call or email if you have questions.
Sara
Sara E. Miller, Ph. D. P. O. Box 3020 Duke University Medical Center Durham, NC 27710 Ph: 919 684-3452 FAX: 919 684-8735
} Date: Wed, 12 Nov 1997 15:46:14 -0600 } To: Microscopy-at-sparc5.microscopy.com } From: laura.rhoads-at-wku.edu (Laura Rhoads) } Subject: Drive Belt for OmU2
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } Hey there, } } Do any of you Reichert afficianados out there happen to know where I can } obtain a drive belt for an OmU2? I called Leica and they told me parts are no } longer available: This of course was after they got over the shock of hearing } one of these babies hasn't been turned into a boat anchor yet. This little } darling cuts like a hot knife through butter, at least it did before the belt } self-destructed so I'd hate to see it go just because the belt is finished. If } anyone knows where I might be able to get a new belt, say for example when you } got that new Ultracut and left the OmU2 parts in that back drawer, or make a } replacement part of susbtitute goods (such as rubber bands, duct tape, etc) } I'd really like to hear from you. } } Thanks a lot! } The material that is used for the drive on the Omu2 is quite different to the material that is used for O rings, and has quite different damping properties to the nitrile rubber oring cord. It can be successfully rejoined by melting the ends against a heated copper plate (or similar) and pressed together and then trimmed. We have also sucessfully used "superglue" after trimming the ends with a grease free razorblade. Very little length is lost. Similar material to the original is also supplied at places that specialize in Vbelt drives, and it too, is also normally joined by melting
Hello everyone ! We want to change our fixation and processing protocol for pulmonary tissues and cells to use HEPES buffer instead of sodium cacodylate buffer. Is anybody out there who has made her/his experience with HEPES buffer in conventional epoxy resin embedment. We are especially interested in experience of lipid retention/extraction.
Heinz Fehrenbach (Inst. of Pathology, TU Dresden, Germany)
1. Generally you use the gold on the mica and just stick the mica to the sample stub (in STM ensuring there is electrical contac between the gold and the stub). Then you generally image downwards finding large islands and flat areas of gold.
An alternative method, making larger areas of flat gold, is to remove the upper layers of gold from the mica - see " Uniformly flat gold surfaces: Imaging the domain structure of organic monolayers using scanning force microscopy" by Stamou_D, Gourdon_D, Liley_M, Burnham_NA, Kulik_A, Vogel_H, Duschl_C in LANGMUIR, 1997, Vol.13, No.9, pp.2425-2428 for a clearer description of this method.
2. I don't think there is.
3. Make it youself.
Giles Sanders Laboratory of Biophysics and Surface Analysis School of Pharmaceutical Sciences University of Nottingham
} Date: Thu, 13 Nov 1997 11:34:48 +0100 } To: ListServer-at-MSA.Microscopy.Com } From: Toufiq ELALLAM {elallam-at-lget.ups-tlse.fr} } Subject: financial support for postdoctoral } } } } ------------------------------------------------------------------------ } } The Microscopy ListServer -- Sponsor: The Microscopy Society of America
We are using the BioRad confocal microscopes to collect stacks of 2-D pictures, transform these into 3-D using a Silicon Grapho=3DEDcs based syste= m with the VoxelWiew software. One of our interests is pathological conditions of the human brain, and we collect stacks os pictures from individual pyramidal or non-pyramidal neurons, visualized by intracellular injections of e.g. Lucifer Yellow, which spreads to every part of the neuron, including all spines. The neurons are collected with a presice location registered from an identified cortical (so far) region, dissected from either peroperative material or postmortem cases.
Characteristic morphological abberrations have been noted in cases of e.g. irretractible epilepsy, and Rett's syndrom. We are further looking to collect infantile autism cases and schizophrena cases.
We have in store many thousands of identified neurons with patient history and other data, which can be transferred to researchers in other parts of the world, for comparison with their own data, and for increasing case numbers to improve statistics. We have done succsssful transfers via the internet.
References:
Atypical pyramidal cells in epileptic human cortex: CFLS and 3-D reconstructions. P Belichenko, A Dahlstr=3DF6m, C von Essen, S Lindstr=3DF6m, C= Nordborg =3D and P Sourander NeuroReport, (1992) 3: 765-768
Application of confocal microscopy for the study of neuronal organization in human cortical areas after microinjection of lucifer yellow P. V. Belichenko, A. Dahlstr=3DF6m, and P. Sourander In: Biotechnology Applications of Microinjection, Microscopic Imagin= =3D g and Fluorescence. Ed. P.H. Bach et al. Plenum Press, New York,(1993) pp.29-35.
Dual channel confocal laser scanning microscopy of lucifer yellow- microinjected human brain cells combined with Texas red immunofluorescence P. Belichenko & A. Dahlstr=3DF6m. J. Neurosci. Meth.(1994) 52: 111-1= 18
Rett syndrome: 3-D confocal microscopy of cortical pyramidal dendrites and afferents Pavel V. Belichenko, Anders Oldfors, Bengt Hagberg, and Annica Dahlstr=3DF6m NeuroReport (1994) 5: 1509-1513
Dendritic morpholgy in epileptogenic cortex from TRPE patients, revealed by intracellular Lucifer Yellow microinjection and confocal laser scanning microscopy. Pavel V. Belichenko, Patrick Sourander, Kristina Malmgren, Claes Nordborg, Claes von Essen, Bertil Rydenhag, Sivert Lindstr=3DF6m, A= nd=3D ers Hedstr=3DF6m, Paul Uvebrant, Annica Dahlstr=3DF6m. Epilepsy Research (1994) 18: 233-247
Micromapping of the Human Brain: Three-Dimension Imaging of Immunofluorescence and Dendrictic Morphology Using Dual- Channel Confocal Laser Scanning Microscopy Pavel V. Belichenko and Annica Dahlstr=3DF6m Human Brain Mapping (1994) 1: 185-193
Morphological aberrations in therapy resistant partial epilepsy (TRPE); Confocal laser scanning and 3-D reconstructions of Lucifer yellow injected atypical pyramidal neurons in epileptic human cortex P Belichenko, P Sourander and A Dahlstr=3DF6m. Molec. Neurobiol.(1994) 9: 245-251
Studies on the 3-dimensional architecture of dendritic spines and varicosities in human cortex by confocal laser scanning microscopy = =3D and Lucifer Yellow microinjections. Pavel V. Belichenko , Annica Dahlstr=3DF6m J. Neurosci. Methods (1995) 57: 55-61
Contacts between serotoninergic fibres and dorsal horn spinocerebell= ar tract neurones in the cat and rat; a confocal microscopic study. Jankowska, DJ Maxwell, S Dolk, P Krutki, PV Belichenko and A Dahlstr= =3D =3DF6m. Neuroscience,(1995) 67: 477-487,
Mild cortical dysplasia: A three-dimensional study of dendritic morphology Pavel V. Belichenko and Annica Dahlstr=3DF6m Dysplasia of cerebral cortex and epilepsy , Eds. R. Guerrini et al Lippincott-Raven Philadelphia-New York (1995) pp.65-70,
Mapping of the human brain in normal and pathological situations: t= =3D he single cell and fiber level, employing lucifer yellow microinjection= =3D , carbocyanine dye tracing, immunoflourescence, and 3D confocal laser scanning microscopy reconstraction. Pavel V. Belichenko and Annica Dahlstr=3DF6m Neurosci. Protocols (1995), 95-050-03-01-30
Confocal laser scanning microscopy and 3-D reconstructions of neuronal structures in human brain cortex. Pavel B. Belichenko and Annica Dahlstr=3DF6m NeuroImage (1995) 2: 201-207
Calretinin-positive Cajal-Retzius cells persist in the adult human neocortex P.V.Belichenko, D.M. Vogt Weisenhorn, J. Myklossy and M.R. Celio Neuroreport (1995) 6, 1869-1874
Morphological study of neocortical areas in Rett syndrome. P V Belichenko, B Hagberg, A Dahlstr=3DF6m J Neuropathol (1997) 93: 50-61
Interested parties may contact us at this e-mail address.
Annica Dahlstr=3DF6m, MD, PhD and Pavel Belichenko, MD, PhD Prof., G=3DF6teborg University Prof. Brain Res. Institute, Moscow
Annica Dahlstr=3DF6m, MD, PhD Professor Inst. of Anatomy and Cell Biology Div of Neurobiology Medicinaregatan 3-5 S-413 90 G=3DF6teborg
I have been involved with the maintenance of electron microscopes for 33 years. Firstly as a service engineer and then through my own training organisation where we train both operators and service engineers. We run=
regular maintenance courses around the world when we get a good idea of which cleaning materials and solvents are available. =
I have been watching the discussions with interest to see if there were many holes in the cleaning explanations. That said may I toss in my few pennies (cents) worth?
TUNGSTEN Gun Systems
The cathode assembly should be cleaned every filament change, the anode every other change and the electron gun at least once a year.
Materials - Almost any metal polish may be used to clean electron gun components however it must not be LONG LIFE. Long life additives coat th= e cleaned item with a polymer that causes chaos in the electron gun. Look out for any indication on the bottle or tube that the manufacturer is claiming that you will not need to clean the metalwork so often after usi= ng their product!
Method - Almost more important than the cleaning efficiency is our abilit= y to completely remove the polishing media. So many service call outs are due to problems caused through inefficient removal of the media. For thi= s reason it makes sense to use a metal polish that is easily removed by a solvent for tungsten. In this way we not only remove the metal polish bu= t also clean the areas that are difficult to approach with the polish, nook= s and crannies! Also very important is the need to clean without damaging the component, scratching it or placing cotton hairs within the "traps" that the manufacturers seem to put in our way. The best cleaning techniq= ue is a wet clean, that is to use solutions and an ultrasonic cleaner. In this way the damage that mechanical forces apply to the components are minimised. Sure the cathode aperture may need a little more encouragemen= t to give up its deposit but only do this if the wet cleaning procedure fal= ls short. We like "Silvo" or "Bluebell" or "Brasso", liquid metal polishes that will mix with a dilute ammonia solution to form a cleaning media, b= ut a solution that may be removed with further washes in dilute ammonia. Th= e mix - 10% metal polish in 90% ammonia solution - where the solution is 1= 0% ammonium hydroxide in water. Place the components, one at a time, in the=
solution with their least important face down wards. Never put gun components together in the solution as they will damage each other. Do n= ot put an aluminium cathode in ammonia as it will go black, oxide! After 20=
minutes in an ultrasonic the component should be clean, wash off in runni= ng water and run for another 5 minutes in straight 10% ammonium hydroxide i= n water. Swill off with running water and then wash in alcohol and dry. =
NEVER throw away your solutions until you have reassembled the cathode as=
it is quite possible for the small screws to have fallen out and to resid= e in the debris at the base of one of the cleaning containers. If you do have a deposit remaining in the aperture area of the cathode a little mechanical effort with the cleaning media may be required,
The gun chamber IS important and this should be cleaned through disassemb= ly once a year, particularly with a TEM. Dirty guns hold gas and induce mic= ro discharge which spoils images. Clean the gun chamber with metal polish, remove the metal polish with dilute ammonia and buff up the walls with a clean chamois or dear skin leather. To retain the cleanlyness of the chamber, each time you change a filament buff up the walls with the leather. If the chamber smells, oily-ozone smell, but is not visibly stained, this is the result of discharge and all traces of the smell shou= ld be removed with dilute ammonia.
Look after your gun, it is probably the dirtiest area of the microscope, other than the specimen area in a SEM or the camera chamber in a TEM, its=
state will determine the ultimate performance of the instrument and your filament life.
LANTHANOM HEXABORIDE Technique developed by Biology E.M. Unit Canberra
Clean the cathode with 25% hydrochloric acid in water by immersing for 60=
seconds and then cleaning with a weak alkaline (ammonia or sodium hydroxide). Wash with water and then alcohol before drying.
LaB6 sources should last a long time (1000 hours plus) but they do need a= n intermediate cleaning session about every 250 to 350 hours. Some people amaze us by getting away with 1100 hours without cleaning but this is the=
exception not the rule.
Good luck!
*************************************************************************= ** ********************************************* Steve Chapman Senior Consultant
I received this inquiry today, and wondered if any of you could help. Please respond directly to Margaret, and not to the listserv.
Best regards, Steven Slap
} Return-Path: {nelsonm-at-Zeus.UCHSC.edu} } Delivered-To: ebsience-at-vgernet.net } From: "Margaret Nelson" {Margaret.Nelson-at-UCHSC.edu} } Organization: UCHSC Educational Support Services } To: ebs-at-ebsciences.com } Date: Tue, 11 Nov 1997 16:32:37 MST-0700 } Subject: Spurr Resin Toxicity } X-Confirm-Reading-To: "Margaret Nelson" {nelsonm-at-Zeus.UCHSC.edu} } X-pmrqc: 1 } Priority: normal } } At the suggestion of my doctor, I have been searching the internet } for information on the long-term effects of exposure to Spurr Resin. } From your web page, I was able to obtain the ingredients list, and } also a comment about a carcinogenic risk. This is the only } information I have found so far. } } Would you perhaps know of other sites I might try, or of physicians } or researchers who might know of others who have had an exposure to } this resin. I have not worked in the field of electron microscopy } for over 11 years, but the ramifications of the resin spill to my } legs (manifesting as spontaneous bruising) continues. I'm wondering } if others have experienced this, and what the future may hold. (What } sort of carcinogenic risk does this resin carry?) } } I'd be greatful if you could put me in touch with someone who might } have some useful information to share, and/or with a researcher } studying these questions who would be interested in my experiences. } Thanks for your time. } } Margaret G. Nelson } Univ. of Colo. Health Sciences Center } 4200 E. 9th Ave., Box A-066 } Denver, CO 80262 } (303) 315-6404, fax 315-6417 } } ******************************** Energy Beam Sciences, Inc. Adding Brilliance To Your Vision ebs-at-ebsciences.com http://www.ebsciences.com/ ********************************
I am an undergraduate and need help on staining blood cells which are fixed with 0.5% glutardialdehyde. My intention is to distinguish between monocytes and lymphocytes. Please do not tell me to use immunohistochemistry because it is not possible. The reason for this is that I also use very bright fluorescent latex beads ( FL-1 ) together with the cells and because of that I cannot take another fluorescent marker ( FL-2 ). I tried to stain my cells with Azur-B Eosin ( Romanowsky staining ) but it did not work. The cells just looked black or something like a very dark violet and I was unable to tell cytoplasm from nucleus. I think my problem is the glutardialdehyde but I have to use that!!! Does anyone have an idea about how to stain these fixed cells??????
Another solution could be that I separate lymphocytes and monocytes before I apply them for the microscope. Could anyone help me with that??? To isolate mnc from whole blood I use a Ficoll-Paque gradient centrifugation technique. I tied adhesion assays to separate monocytes from lymphocytes ( that means that the monocytes adhere to the petri dishes and the lymphocytes are mostly in the supernatant ), but the monocyte fraction is not very pure ( FACS analysis ) and I have a lot of debris because I have to use EDTA and a rubber policeman to get the monocytes off the plate.
Thank you very much!
Yours sincerely, Kathrin Augenstein
Institute of Immunobiology Stefan-Meier-Str. 8 79104 Freiburg Germany Fax. no.: 0041-761-2035446 e-mail: augenstk-at-ruf.uni-freiburg.de
10-Day Short Course on 3D Microscopy of Living Cells
June 17 - 28, 1998
and the Second, Post-course Workshop on
3D Image Processing June 30 - July 2
in association with the
UBC BioSciences Microscopy Facility
and the
Department of Computer Science
University of British Columbia Vancouver, BC, Canada
Organized by Prof. James Pawley University of Wisconsin-Madison
THE PURPOSE OF THE COURSE
Modern methods of 3D light microscopy promise a revolutionary improvement in our ability to view living cells. To help convert this promise to reality for a wider selection of biological scientists, an intensive ten day residential course concentrating on all aspects of the 3D Microscopy of Living Cells will be again held at the University of British Columbia, in June of 1998. The course will cover every-thing from basic microscopy to the highest levels confocal microscopy.
The course will cover:
* Quantitative 2D light microscopy * 3D imaging in confocal and widefield * Fluorescent and backscattered light * Pixelation: The Nyquist Criterion * Lasers and laser tweezers * Objectives and aberrations * Scanning-systems: AODs and mirrors * Wide field/deconvolution techniques * Detectors: operation and performance * Optimal pinhole size/photon efficiency * Dye design, characteristics and use * How to keep your cells alive * Two-photon excitation * Video-rate confocal imaging * Measuring ion concentrations * Display and measurement of 3D data * Digital hard copy and storage
Morning lecture/demonstrations will lead to hands-on laboratory exercises each after-noon that will utilize most of the commercial instruments currently available for 3D micro-scopic imaging. Students will work in groups of 3 or 4 throughout the discussion and labo-ratory sessions, and will complete a live-cell 3D study on their own specimen.
Last year, 11 separate 3D microscopical workstations were available for student use under the supervision of an international faculty of 15. We expect to have even more workstations in 1998. Including manufacturers representatives, the teacher/ student ratio will be more than 1:1.
International Academic Faculty
* Jon Art University of Illinois * Pin Ching Cheng State U. of New York, Buffalo * Rachel Errington University of Nijmegen * Jim Pawley University of Wisconsin-Madison * Ernst Stelzer EMBL, Heidelberg * Michael Weis Agriculture Canada * Nick White Oxford University
International Commercial Faculty
* Dan Focht Bioptechs, PA * Ted Inou=E9 Universal Imaging, PA * Larry Keenan Cell Robotics, NM * Paul Millard Molecular Probes, OR * Sigrid Myrdal Multidimensional Imaging, WA * Paul Negulescu Aurora Biosciences, CA * Hans Van der Voort Scientific Volume Imaging, NL
TUITION
Course tuition is $1,950 US and includes lunches. On receipt of 50% deposit, all students will receive preliminary group assignments and a copy of the textbook, Handbook of Biological Confocal Microscopy, (Plenum, 1995). The tuition fee includes single tickets for the Opening Reception, the Manufacturer's Reception and the Beach Party, the textbook and all handouts. Accommodations and meals other than lunch are not included in the tuition fee. APPLICATIONS
Applicants will complete a questionnaire to assess knowledge level and field of interest. Enrollment will be limited to about 24 participants. Selection will be made on the basis of background and perceived need. Those without previous LM experience will be provided with basic texts on request to read before the course begins. Application forms can be down-loaded from the WWW site at
Prof. James Pawley, Rm. 1235, 1500 Johnson Dr., Madison, WI, USA 53706. Phone: 1-608-263-3147, Fax 1-608-265-5315, Email: jbpawley-at-facstaff.wisc.edu
Application deadlines: Application forms must be received by March 1, 1998!
Successful applicants will be notified by April 1, and a deposit of 50% must be received by April 15, 1998 to reserve your position. In general, refunds of the deposit will only be possible if your position can be filled from the Waiting List. The remainder of the fees are due before registration.
DATES:
Applications must be received by Mar. 1/98 Deposit due Apr. 15/98 Registration 8:00 - 7:00 pm Wednesday, June 17/98 Last class will end with lunch Sun., June 28/98
WHO SHOULD ATTEND?
The course is designed for biological research scientists and advanced graduate students who use, or plan to apply 3D microscopy in studies involving living cells. No previous experience in advanced light microscopy is required but applicants will be asked how they plan to use 3D microscopy and to describe a short research project involving living cells that they plan to carry out during the course. Students with other interests in 3D light microscopy will be welcomed if space permits but usually the course is heavily oversubscribed.
Classes meet from 8:30 -12:00 and 1:00 - 6:00 with lecture-demonstrations in the morning and laboratory sessions in the afternoon. On average, only four topics will be covered in each morning session. There will be enough 3D microscopy setups to permit groups of 3-4 students to "learn-by-doing" during a carefully designed set of laboratory sessions. Lab handouts will include detailed questions to stimulate group discussions.
=46rom Sunday to Friday, facilities and supervision will be available until 11:00 pm, for those students who wish to work on their own projects.There
USE OF LEARNING GROUPS
Prior to the course, students will be organized into groups and encouraged to communicate by email/ phone, about the "Living-cell" group projects that they will pursue in the evenings and that will be presented to the class on the last day of the course. It has been found that group interactions make best use of students' prior experience and can be very effective in teaching the practical skills covered in a hands-on course of this type.
ARRANGEMENTS FOR LIVING SAMPLES
Students must contact the Course Organizer to make necessary arrangements for the transport and maintenance of cell lines etc. needed for their projects. Organisms linked in any way with human disease are not permitted because of safety considerations. Transport and customs arrangements for living specimens are entirely the responsibility of the student.
****************************************************************************= * 3D Image Processing Workshop June 30 - July 2
The course will cover 3D image processing for measurement and display. Enrollment is limited to those attending the 3D Micro-scopy course. Tuition : $700 US (lunch incl.) Live-cell Course
WHO SHOULD ATTEND?
The course is designed for biologists working with multidimensional and possibly multicolor microscopical data sets. Getting the data is only half of the battle. Image data in 3, 4 or even 5 dimensions may be difficult to store let alone analyze or display. This course is to help students understand the hardware and software aspects of this problem and give them the techniques they need to make the most of their data.
The course is designed for biologists who need to make measurements on 3D microscopical data sets and then display the results in an effective manner. The course will be taught in a computer laboratory belonging to the Computer Sciences Department at the University of British Columbia which contains 27 SGI Indy workstaions and much of the other equipment needed for the measurement and display of 3D digital image data. Software from a variety of vendors serving the 3D microscopy market will be described, demonstrated and available for use.
Course Organizers * Nick White Oxford University * Hans Van der Voort Scientific Volume Imaging, NL
=46aculty * Pin Ching Cheng State U. of New York, Buffalo * Rachel Errington University of Nijmegen * Alain Fournier Computer Science, UBC * Sigrid Myrdal Seattle, WA
PLAN OF INSTRUCTION
Classes will meet from 8:30 -12:00 and 1:00 - 6:00 with lecture-demonstrations followed immediately by hands-on laboratory sessions using SGI work-stations. Students will "learn-by-doing" with two to a machine. Lab handouts will describe specific exercises to be performed on "canned" data sets.
Students also attending the 3D Microscopy Course, will be able to analyze, process and display the 3D data they have collected from their own specimens. Facilities and supervision will be available until 11:00 PM, for students to work on their own data.
Campus accommodations are student rooms or suites situated in the Walter Gage Residence located two blocks from the lecture-lab facilities and one block from the Student Union Building. The Union contains a large cafeteria, lounge, bank, etc. Many of the rooms in the Gage Residence have breath-taking views of the mountains of North and West Vancouver, and of the Pacific Ocean. A variety of accommodation types are available: $Cdn ($US)
- Single room w/shared washroom $30(23)
- Single room w/private bath $59(44)
- Double room (kitchenette, priv. bath, TV, phone, double bedroom plus separate sitting room) $85(63)
- Triple suite (twin bedroom and queen Murphy bed in sitting room, balcony,
kitchen, bath, TV, phone) $99(74)
(All fees are per night. Add 15% VAT. US rates are approximate and vary with exhange rate.)
Students are encouraged to bring friends or family members to enjoy the pristine beauty of the Vancouver area and the miles of lovely beaches that surround the campus. Arrangements can easily be made to extend your stay before or after the course.
MEALS
Lunches and morning and afternoon snacks are provided. Other meals can be purchased in the Union Cafeteria or any of a number of nearby restaurants. The Opening Reception and the Beach Party and the Manufacturer's Reception are included in the tuition fee. Additional tickets can be purchased for spouses and accompanying persons.
TRAVEL
Air:
Since the normalization of airfares between Canada and the US, fares to Vancouver from other parts of North America have been substantially reduced. The University campus is a 20-minute taxi ride from Vancouver International Airport. Students will receive a comprehensive selection of tourist information after their application has been accepted.
Bus:
=46or family members wishing to see the many sights, Vancouver has an excellent system of inexpensive and convenient public transportation.
Tours: Tours of Vancouver and environs can be arranged.
For more information & application forms, please contact the Course Organizer:
Prof. James Pawley, 1500 Johnson Dr., Madison, WI 53706. Phone: 1-608-263-3147/265-5315 fax. Email: jbpawley-at-facstaff.wisc.edu.
**************************************** Prof. James B. Pawley, Ph. 608-263-3147 Room 1235, Engineering Research Building, FAX 608-265-5315 1500 Engineering Dr., Madison, WI, 53706 JBPAWLEY-at-FACSTAFF.WISC.EDU "A scientist is not one who can answer questions but one who can question answers." Theodore Schick Jr.,
} } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } } Is there anyone out there that currently does particle size analysis by } both Microscopy and Laser/Light Scattering techniques that can tell me if } there is a listserver or newsgroup that deals with PSA specifically? } } Thank you in advance! } } Hi, there,
Most recently I have done a lot of particle size analysis in the use of either TEM or OP. The particles actually are such sort of precipitate in metallic systems. Would you put more details in terms of what would you really want to know, especially for what kind of materials you are working for.
Peiyi Wang
Research Fellow Department of Engineering Materials University of Southampton Southampton SO17 1BJ UK
I switched to HEPES about 14 years ago for both my Paraformaldehyde/Glutaraldehyde buffer and for my osmium buffer. Safer, better for environment, and cheaper (I think). I noticed no difference compared to cacodylate (which I had previously used). A couple of years ago, I got into a discussion in which a colleague was touting PIPES as a better alternative. The logic is that HEPES has a pKa of 7.5. I use it at 7.4 for my fixes. Aldehyde fixes tend to acidify over time, therefore, since you start on the low side of the pKa and continue to fight a drop on that side, you have less buffering capacity. PIPES on the other hand, has a pKa of 6.8 so if you started at 7.4, you would have more buffering capacity (0.5 on both sides of the pKa). This is good logic but I didn't bother switching. Good luck.
-------------. } } Hello everyone ! } We want to change our fixation and processing protocol for pulmonary tissues } and cells to use HEPES buffer instead of sodium cacodylate buffer. Is anybody } out there who has made her/his experience with HEPES buffer in conventional } epoxy resin embedment. We are especially interested in experience of lipid } retention/extraction. } } Heinz Fehrenbach (Inst. of Pathology, TU Dresden, Germany)
Thomas E. Phillips, Ph.D. Associate Professor of Biological Sciences Director, Molecular Cytology Core Facility 3 Tucker Hall University of Missouri Columbia, MO 65211 (573)-882-4712 (voice) (573)-882-0123 (fax)
You may be able to circumvent the effects of glutaraldehyde on the 'stainability' your cells with borohydride reduction:
"The pH dependence of borohydride as an aldehyde reductant" Bayliss, O.B. and C.W.M. Adams. Histochemical Journal 11:111-116, 1979.
Remember that borohydride solutions deteriorate VERY quickly, within minutes of preparation. Good luck!
Geoff -- *************************************************************** Geoff McAuliffe, Ph.D. Neuroscience and Cell Biology Robert Wood Johnson Medical School 675 Hoes Lane Piscataway, NJ 08854 voice: (732)-235-4583; fax -4029 e-mail: mcauliff-at-umdnj.edu ***************************************************************
I am not sure whether you have a flow cytometer or not, but a fluorescent microscope will work as well. You can stain your Monocytes with CD14 monoclonal antibody that is conjugated to either FITC FL-1) or PE (FL-2). Your lymphocytes can be stained with CD3 monoclonal antibody that is conjugated to either FITC or PE. You can use the two monoclonal antibodies together in which case the monoclonal antibodies will have to be conjugated to different fluorochromes, for example CD14-FITC combined with CD3-PE You can obtain the monoclonal antibody combination from Becton Dickinson Immunocytometry Systems, 2350 Qume Drive, San Jose, CA 95131-1807, Phone Number ( 800) 223-8226 .
In addition Becton Dickinson also sell the "TriTest" in which three different leukocyte specific monoclonal antibodies are combined together, CD45 is conjugated to a very bright red fluorochrome PerCP and monocytes and lymhocytes have different binding capacities for the CD45 monoclonal antibody. Note CD45 is Pan leukocyte monoclonal antibody that identifies all leukocytes.
FIXATIVE
Try using paraformaldehyde instead of glutaraldehyde.
I hope the above information is of help to you. Good Luck.
Bob Holthausen 11/13/97 11:52 AM
To: Sam Coker/SLSNY/Pall/US-at-Pall cc:
Yours sincerely, Kathrin Augenstein
Institute of Immunobiology Stefan-Meier-Str. 8 79104 Freiburg Germany Fax. no.: 0041-761-2035446 e-mail: augenstk-at-ruf.uni-freiburg.de
Yet another question from the unpredictable world of multi-user facilities. One of our users embeds samples in epoxy and polishes them to eliminate topographical variables. He requires both imaging and EDS, which precludes metal coating for conductivity.
He was wondering about the availability of epoxies containing conductive components, which might allow us to use high-vacuum SEM with secondary electron imaging. Does such a thing exist? Has anyone ever used a standard epoxy and added their own conductive "secret recipes" before polymerizing?
I'm aware that carbon coating is an option, as well as painting conductive stripes of colloidal carbon or silver to the edge of the embedded materials and down to the aluminum stub. The idea of a conductive epoxy is intriguing, though, for the time and mess-saving possibilities.
As usual, thanks in advance for the always helpful replies I get to these queries.
Randy Tindall Electron Microscope Laboratory Box 3EML New Mexico State University Las Cruces, NM 88003
We have been experimenting with the use of HEPES as a non-toxic substitute for NaCacodylate for TEM during the past 6 months. So far the results have been good for mammalian and amphibian tissues (cardiac muscle, pancreas, heart, tongue). The membranes look good and we seem to have no trouble retaining lipid droplets in frog atrial muscle. I would be interested in anything anyone else has to offer. Also, I am assuming that HEPES is less toxic than Cacodylate. If anyone knows otherwise, I would like to hear about it.
Dr. Marie E. Cantino Dept. of Physiology and Neurobiology, U-131 University of Connecticut Storrs, CT 06269 Ph: 860-486-3588 Fax: 860-486-1936
Hi everybody Here is my (short)experience on CDR. I have a Sony CDR 928 on IDE Bus ( all my system is IDE not SCSI)and the first pb I encounter is that my old Windows95 version never never recognize this CDR. So I installed an OSR2 version on a new disk and all was OK. The software is easy CD pro from adaptec (upgraded for IDE). First writing (600Mo) no problem but impossible to read the datas on my 1 years old CD 8x. I check on many other even on a very old 2x Mitsumi and all was OK. So I change for a 24x Pionneer (the CDs were from Sony). All that takes at least one week late at night! My conclusions are the following: Writting speed doesn't affect reading, it's just a safety, the slower the safest. Never use Multisession, the price of CDs is now as low as 2$ and doesn't justify that. I use different manufacturer for CDs (SONY TRAXDATA...) without PB. You can never be sure that your work can be read on all CD for example I've made an Audio which is readable by all CD except on a JVC CD! I enclose a part of my Easy CD pro user's manual that prove that manufacturers know the problem. I have no interrest in any of the above company (just problem with some!) and this is my personnal opinion. If more information needed pls Email me.
FROM EASY CD PRO VERSION 2.0 ADAPTEC USER'S GUIDE
Problems Reading Recordable CDs If you have successfully written a CD but have problems reading it, there are a number of possible reasons : * If the CD can be read on the CD recorder but not on a standard CD-ROM drive, check in Disc Info and Tools to make sure that the session containing the data you just wrote is closed. CD-ROM drives cannot read data from a session which is not closed. =95 If your CD is ejected, or you receive an error message, or you have random problems accessing files from the CD, the problem may be that your CD-ROM drive is not well calibrated to read recordable CDs.
a If you recorded the CD using the DOS filenames option in the File Names tab, but there are nonetheless difficulties in reading back the CD on DOS or Windows OR 3.1 system, it may be that you have an older version of MSCDEX (before version 2.23) on your system.
Problems Reading Multisession CDs If you can see only data recorded in the first session on the CD but not in subsequent sessions, it may be that =95 You recorded the CD in CD-ROM (Mode 1) format, while your multisession CD-ROM drive only recognizes CD-ROM XA (Mode 2) multisession CDs.
or, =95 Your CD-ROM drive does not support muti session at all.
If you can see only data recorded in the last session, you may have forgotten to link your new data with data previously recorded on the CD. Make sure to select a track in the Load Contents tab before recording.
CD-ROM Drive Incompatibility with Recordable CDs Sometimes, it appears that you wrote a CD without trouble and can read it on your CD recorder ; however, when you put it in a standard CD-ROM drive, the CD is ejected, or you get error messages such as no CD-ROM or not ready reading, or you have random problems accessing some files or directories. You may find that the problems vanish completely when reading the CD on a different CD-ROM drive. This maybe due to compatibility problems with some CD-ROM drives, especially older ones, and recordable CDs. Some CD-ROM drives' lasers are not calibrated to read recordable CDs, whose surface is different from that of factory-pressed CDs. If your CD-ROM drive reads mass-produced (silver) CDs but not recordable CDs, check with the CD-ROM drive manufacture to determine whether this is the problem. In some cases , an upgrade is available which will solve the problem. The combination of CD brand and CD recorder can make a difference. Use CD media recommended by your CD recorder manufacturer.
I know this isn't strictly microscopy, but in light of the recent discussion about data storage, perhaps someome will be able to help.
We have an HP 1300T (1.3 GB, 650 MB on each side) magneto-optical drive that has failed us. It still reads and writes the disks okay, BUT ONLY when it accepts the disks. Normally (99+%), it tries three times to load the disk and then gives up.
We blew a lot of dust out of the unit and have opened it up and cleaned every place we could easily find (and a few more that we couldn't). Yet it still fails to accept cartridges.
HP has told us that the unit can only be replaced at a net cost of $650. I have also been told that encountering a failure after 2-1/2 years, with use a couple times a week over that period, is about par for the course. To say the least, that sounds quite short to me. I don't particularly wish to invest more money in such a short-lived option. (There was always the question of obsolescence but apparently there is also one of short working life.)
So the request- Does anyone out there have a drive that we could make some arrangements with to retrieve the data from our library of cartridges. We have about 10 GB of data to pull off. Then we would like to get away from the M-O drive and go to another media, probably CD-rewritable.
If perchance we could borrow someone's drive for a short period, I think we would be glad to leave you with our inventory of cartridges after we are done with the exercise. Any takers?
---------------------------------------------------- Warren E. Straszheim 23 Town Engineering Iowa State University Ames IA, 50011 Phone: 515-294-8187 FAX: 515-294-8216
We used to use some copper-filled diallyl pthallate (sp?) to embed coal. It was a hot-preesed, thermosetting material from Beuhler or Leco. However, there was still a substantial fraction of the surface that was nonconductive. I don't recall if we could count on it providing a conducting path to ground. I think we C-coated most of our samples anyway.
At that time I was looking at S in coal and had little trouble from the C coating.
At 11:00 AM 11/13/97 -0700, you wrote: } Hi, } } Yet another question from the unpredictable world of multi-user facilities. } One of our users embeds samples in epoxy and polishes them to eliminate } topographical variables. He requires both imaging and EDS, which precludes } metal coating for conductivity. } } He was wondering about the availability of epoxies containing conductive } components, which might allow us to use high-vacuum SEM with secondary } electron imaging. Does such a thing exist? Has anyone ever used a } standard epoxy and added their own conductive "secret recipes" before } polymerizing? } } I'm aware that carbon coating is an option, as well as painting conductive } stripes of colloidal carbon or silver to the edge of the embedded materials } and down to the aluminum stub. The idea of a conductive epoxy is } intriguing, though, for the time and mess-saving possibilities. } } As usual, thanks in advance for the always helpful replies I get to these } queries. } } Randy Tindall ---------------------------------------------------- Warren E. Straszheim 23 Town Engineering Iowa State University Ames IA, 50011 Phone: 515-294-8187 FAX: 515-294-8216
I have a suggestion for the poor fellow who gets dry, cracked skin on his fingers in the winter: cut off your fingers. All of them. An ax should work finebut you could also use a power saw. Then you will never have to worry about dry cracked skin on your fingers. It will also be difficult for you to type, so I will probably get slightly fewer stupid e-mails about non-microscopy subjects.
Epoxy Technology, Inc. manufactures a complete spectrum of epoxies including at least four that are electrically conductive; all contain silver. I have not used any of them myself. BTW, their EPO-TEK 353ND is the same as Gatan's G-1, which I do use.
Call them at 800 227 2201 for a catalog.
Michael K. Cinibulk UES, Inc. Air Force Research Laboratory Materials and Manufacturing Directorate Wright-Patterson AFB, OH 45433-7817 937 255 9339 phone 937 656 4296 fax cinibumk-at-ml.wpafb.af.mil
There is a position open now for an electron microscopy specialist . Prepare ultra thin sections, and photogragh them using JEOL 1200EX. Darkroom, Adobe Illustrator/Photoshop.
Salary commensurate with experience.
Mail or fax resume and two letters of recommendation to:
Dr. Peter Sterling 123 Anatomy/Chemistry BLDG Department of Neuroscience University of Pennsylvania Philadelphia, PA 19104-6058
The matter of cleaning parts and components of vacuum systems is discussed in considerable detail on p. 69 - 74 of my book 'Vacuum Methods in Electron Microscopy' (Ashgate Pub. Co. Tel: 800-535-9544 ). Cleaning methods are extremely important in determining the pumpdown characteristics of vacuum systems, and the practical ultimate vacuum attainable in them, because of the overriding contribution of the outgassing phenomenon to these processes.
In particular, on p. 72 I cite a recommendation by Peter Sewell, of Lab-6 Inc. (a company that deals extensively with lanthanum hexaboride), that lanthanum hexaboride deposits can be effectively removed from Wehnelt cylinders by soaking them for about a minute in a solution consisting of one part by volumne of concentrated hydrochloric acid and four parts water, followed sequentially by thorough rinses with water, dilute ammonia, deionized water, and isopropyl alcohol, whereupon they are dried with a jet of clean hot air.
Wilbur C. Bigelow, Prof. Emeritus Materials Sci. & Engr., University of Michigan Ann Arbor, MI 48109-2136 e-mail: bigelow-at-umich.edu; Fx:313-763-4788; Ph:313-764-3321
} I received this inquiry today, and wondered if any of you could help. } Please respond directly to Margaret, and not to the listserv. } } } } At the suggestion of my doctor, I have been searching the internet } } for information on the long-term effects of exposure to Spurr Resin.
I'd like to see the responses to this query on the listserver, in addition to the direct response, please.
Caroline Schooley Educational Outreach Coordinator Microscopy Society of America Box 117, 45301 Caspar Point Road Caspar, CA 95420 Phone/FAX (707)964-9460 Project MICRO: http://www.MSA.microscopy.com/ProjectMICRO/Books.html Intertidal invertebrates: http://www.fortbragg.k12.ca.us/AG/PCI/
Do you now if we have a newgroup on glass sciences? Currently I am editing some data on glass transition temperatures on some simple systems such as Al2O3-P2O5 and MgO-SiO2. If anyone have referrences on these glass transition temperatures or viscocity or know if we have a glass news group, please let me know.
Acme Conductive Adhesives (Division of Allied Products Corp. / New Haven, CT) used to sell a product called "E-Solder No. 3022," which is a conductive epoxy containing silver. It was intended as a substitute for solder in electronics repair when soldering isn't possible. I haven't used it for SEM. Hope this is helpful.
Scott Schwinge University of Washington Friday Harbor Labs 360-378-2165
} Yet another question from the unpredictable world of multi-user facilities. } One of our users embeds samples in epoxy and polishes them to eliminate } topographical variables. He requires both imaging and EDS, which precludes } metal coating for conductivity. } } He was wondering about the availability of epoxies containing conductive } components, which might allow us to use high-vacuum SEM with secondary } electron imaging. Does such a thing exist? Has anyone ever used a } standard epoxy and added their own conductive "secret recipes" before } polymerizing? } } I'm aware that carbon coating is an option, as well as painting conductive } stripes of colloidal carbon or silver to the edge of the embedded materials } and down to the aluminum stub. The idea of a conductive epoxy is } intriguing, though, for the time and mess-saving possibilities. } } As usual, thanks in advance for the always helpful replies I get to these } queries. } } } Randy Tindall } Electron Microscope Laboratory } Box 3EML } New Mexico State University } Las Cruces, NM 88003
Randy Tindall wrote: } He was wondering about the availability of epoxies containing conductiv= e } components, which might allow us to use high-vacuum SEM with secondary } electron imaging. Does such a thing exist? =
Allied High Tech Products has a Conductive Mounting Powder (order # 169-10005) with carbon particles. Allied High Tech (800) 950-9347 or (310) 635-2466
or
Electron Microscopy Sciences has a Conductive Cold Mount (# 50452-01) wit= h copper particles. EMS (800) 523-5874 or (215) 646-1566
"I have no commercial or financial interest in the companies stated above= , except within Mexico."
On Thu, 13 Nov 1997 JMARDINL-at-IMO.Intel.Com wrote:
} I have a suggestion for the poor fellow who gets dry, cracked skin on his } fingers in the winter: cut off your fingers. All of them. An ax should } work finebut you could also use a power saw. Then you will never have to } worry about dry cracked skin on your fingers. It will also be difficult } for you to type, so I will probably get slightly fewer stupid e-mails } about non-microscopy subjects.
Thank you for your kind suggestion, which I will add to the summary list of responses that I posted to the list. We can only hope the suggestion will be archived for future generations of microscopists.
I trust that _no one_ will feel the need to unnecessarily clutter the list with redundant thanks.
The suggestion was certainly novel, but I would be remiss in not pointing out (so to speak) the unexpected downside. When using my new voice recognition software, I find my lips chap more easily. I will, however, seek advice for this problem elsewhere.
*Received: from SpoolDir by IM-PW (Mercury 1.13); Thu, 13 Nov 97 22:19:47 -1800 *Return-path: {Microscopy-request-at-sparc5.microscopy.com} *Received: from Sparc5.Microscopy.Com by mailer.inmat.pw.edu.pl (Mercury 1.13); * Thu, 13 Nov 97 22:19:36 -1800 *Received: (from daemon-at-localhost) by Sparc5.Microscopy.Com (8.6.11/8.6.11) id LAA05022 for dist-Microscopy; Thu, 13 Nov 1997 11:45:18 -0600 *Received: from bubba.NMSU.Edu (bubba.NMSU.Edu [128.123.3.39]) by Sparc5.Microscopy.Com (8.6.11/8.6.11) with ESMTP id LAA05019 for {microscopy-at-sparc5.microscopy.com} ; Thu, 13 Nov 1997 11:45:10 -0600 *Received: from NMSU.Edu by bubba.NMSU.Edu (8.8.7/NMSU) * id KAA14431; Thu, 13 Nov 1997 10:55:39 -0700 (MST) *Received: from nestor.NMSU.Edu by NMSU.Edu (8.8.4/NMSU-1.18) * id KAA17006; Thu, 13 Nov 1997 10:54:48 -0700 (MST) *Received: from Microspace.nmsu.edu (pc-hadams.NMSU.Edu [128.123.5.46]) by nestor.NMSU.Edu (8.8.6/8.7) with SMTP id KAA20404 for {microscopy-at-sparc5.microscopy.com} ; Thu, 13 Nov 1997 10:56:50 -0700 *Message-Id: {3.0.2.32.19971113110035.00692198-at-cnmailsvr.nmsu.edu} *X-Sender: rtindell-at-cnmailsvr.nmsu.edu *X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.2 (32) *Date: Thu, 13 Nov 1997 11:00:35 -0700 *To: microscopy-at-Sparc5.Microscopy.Com *From: Randy Tindall {rtindell-at-NMSU.Edu} *Subject: SEM/EDS/Conductive epoxies *Mime-Version: 1.0 *Content-Type: text/plain; charset="us-ascii"
Well, this is maybe not exactly an unswer which one may excpect, but it may give an idea how to deal with the problem. We are using old electric discharge machine and it requires from time to time the samples to be glued. So to make, the glue or epoxy conaductive some carbone powder is add.
Regards
Witold Zielinski Warsaw University of Technology Narbutta 85, O2-524 Warszawa Poland
May 21-23 and May 25-27, 1998 North Carolina State University Raleigh, North Carolina, USA
and
June 15-18, 1998 Danish Technological Institute Taastrup, Denmark
This highly regarded hands-on course taught by expert faculty has been presented annually for more than 15 years. It deals with all phases of quantitative and computer-assisted imaging from acquisition and processing through measurement and stereological interpretation. Attendees receive The Image Processing Handbook plus a CD-ROM containing images, algorithms (Photoshop-compatible for Mac and Windows) and an extensive on-line tutorial and course notes on stereology and statistical analysis. The course is appropriate for scientists, technicians and administrators using or intending to use these techniques. Attendees typically come from materials science, geology, biological and medical sciences, pharmaceuticals, food science, industrial quality control, remote sensing, and other disciplines. You are encouraged to bring your own images for the hands-on lab sessions.
For detailed information and registration contact Alice Warren, Dept. of Continuing and Professional Education, N. C. State University, Raleigh, NC 27695-7401, 919-515-4195, fax 919-515-7614, email: alice_warren-at-ncsu.edu
Information is available on-line at the following sites:
} I have a suggestion for the poor fellow who gets dry, cracked skin on his } fingers in the winter: cut off your fingers. All of them. An ax should work finebut you could also use a power saw. Then you will never have to worry about dry } cracked skin on your fingers. It will also be difficult for you to type, so I } will probably get slightly fewer stupid e-mails about non-microscopy subjects. ---------------------------------------------------------------------------- --------------------------------------
I assume the writer, who did not sign his name, is trying to be funny. Frankly I think these remarks are offensive and purile.
E-mails about safety and the side effects of chemicals used in microscopy are entirely "on-subject". There are many reagents used in microscopy which cause many workers a lot of problems and will continue to do so long after the exposure has ceased. Dry skin problems and dermatitis are often caused by exposure to microscopy laboratory reagents.
I share this problem of dry, cracking, bleeding and painful finger tips caused by exposure over many years to Lowicryl K4M, even though I used gloves. I no longer use the chemical but any adverse stimulus such as cold, drying or exposure dehydrating agents can cause a flare up of the condition.
Information on the best way to alleviate such problems from fellow sufferers and/or occupational health experts is useful and relevant. The list is not just for "techie-talk". It is about the subject as a whole, and that includes safety and health. If you don't want to read the e-mails use the delete key before opening, as I and many of us do, on many subjects on this list which don't interest or concern us.
Salzburg, 14th Nov. 1997 ------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America
} I received this inquiry today, and wondered if any of you could help. } Please respond directly to Margaret, and not to the listserv. } } } } At the suggestion of my doctor, I have been searching the internet } } for information on the long-term effects of exposure to Spurr Resin.
Caroline Schooley WROTE: Educational Outreach Coordinator Microscopy Society of America Box 117, 45301 Caspar Point Road Caspar, CA 95420 Phone/FAX (707)964-9460 Project MICRO: http://www.MSA.microscopy.com/ProjectMICRO/Books.html Intertidal invertebrates: http://www.fortbragg.k12.ca.us/AG/PCI/
"I'd like to see the responses to this query on the listserver, in addition to the direct response, please."
I would like to have this/these informations too (either via MSA-server or directly to my e-mail-box: W.Muss-at-lkasbg.gv.at) Thank you very much for your efforts!
Only an addition: the new (actual) EIDE Bus ("DMA33")has a throughput of 33MB/sec and is thus nearly as fast as UW-SCSI.
Richard E. Edelmann wrote: Things to keep in mind with these numbers (1) you'll never see these speeds in reality - they are all determined in ideal situations not real world usage, but they are comparable with each other; (2) Actual transfer rates will vary depending on the interface used (i.e. the max. throughputs for the interfaces are EIDE (1-10MB/sec) vs SCSI (5-10MB/sec) vs SCSI-Wide (20MB/Sec) vs SCSI-UltraWide (40MB/Sec) vs parallel ports ( {1 vs Fiber Coupling (a.k.a. Fire Wire, 100+MB/Sec), (3) System configuration will also effect this; i.e. what CPU, what BUS speed, how much memory (RAM) what other components are in the system, what operating system, etc. , (4)
At 08:56 12.11.97 -0500, you wrote: } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America
In reply to a question on the staining of liposomes posted on Nov 03, I replied with the following on Nov 04:
} .......I have a couple of suggestions:
} 1] Apply your suspension to the Formvar surface of the support film rather } than the carbon surface. You may 'catch' more of the particles that way......etc. etc.
It only showed up in my mail box today - November 13 (I am assuming it appeared in everyone's box today also). Does anyone else experience delays like this in their postings?
Master Bond EP 75 is a graphite filled two part epoxy which is electrically conductive. It is rated at 50 ohm/cm, but I measure about 10k ohms/cm.
Metal particles cast and polished in this material show no charging when imaged at fast or slow rates in BSE or SE mode in my SEMQ. Nice to see the original colors of a material through the light optics. X-ray count rates seem OK.
It may be suitable for high vacuum since it contains no solvents. I can't melt a hole in the stuff with a 100 nA focused beam.
Adhesion is excellent. In fact, it sticks to silastic mold perimeters.
Mixing is a little fussy. 3 parts to 100. A perfect mix might get the 50 ohm/cm value. Shelf life is supposed to be less than a year and it's expensive.
The grain size of the carbon filler is relatively coarse. Colloidal graphite might be better.
This posting is definitely to help you people and not Master Bond, a company I did not find especially cooperative toward experimenters.
Master Bond is located in Hackensack, NJ. Phone 201 343 8983.
Knowing the specific resin would be a help. I have several methods for H&E staining and they are dependant on the type of plastic the tissue in embedded in.
-- Begin original message --
} Does anyone have a method for the H and & E staining of resin sections. I } would appreciate any methods or references } TIA Joan Clark } } }
-- End original message --
regards, Bob Robert Schoonhoven Laboratory of Molecular Carcinogenesis and Mutagenesis Dept. of Environmental Sciences and Engineering University of North Carolina CB#7400 Chapel Hill, NC 27599 Phone office 919-966-6343 Lab 919-966-6140 Fax 919-966-6123
If ever an intrinsically conductive polymer is developed which can be cast or hot pressed, I want to know. Conductive polymers are not uncommon these days, but not in a form useable for specimen mounting. Current conductive resins use tricks like adding iodine to the polymer chain to free-up some conductance electrons. ...A nice "tracer" too - unless you need to analyze for I. I have only found them in milled, "set" powder form.
I have used the silver epoxy and it does work. The Ag flakes are usually rather large, however, leaving lots of epoxy to charge at high mag. It can also be rather expensive to use for large "met" mounts. For economy, embed the specimen in a small amount of Ag/epoxy, mount in conventional mount, prepare, then carbon paint the remaining insulator.
The carbon loaded thermoset also works in a limited way. I have had problems with this material being difficult to clean. It is extremely difficult NOT to leave a nearly (optically) transparent film on a polished metal surface. The compounds I have tried *seem* to be slightly soluble in alcohols. If dried on the surface (often blowing w/N2 is not enough), it is back to the polishing wheel for removal.
Of the commercially available materials, I have had the best success with copper loaded hopt press resin. I used to get mine from Struers, but I understand they no longer make it. It does have the problem of charging resin islands as the structure is a network of Cu surrounding "islands" of resin. Still tough if you need to be near an edge. The bulk conductivith is excellent.
I understand there is a similar material using iron loading, but I have not tried that one....
I have also "brewed" my own conductive "cold-set" resin by adding a very rich loading of zinc DUST to acrilic/polyester type resins. The bulk conductivity is poor, but was sufficient to prevent charging in my application. BEWARE of zinc dust. It is reactive, like many metal powders/dusts. Be sure it will not cause problems (boom!, fire!, etc:) with a resin you may choose to combine with it!
Whenever possible, I just "paint" around the specimen using carbon paint. Using a 0000 sable brush, C paint thinned to an appropriate viscosity, and a 20x stereo optical scope, it is possible to "run" the paint right to the specimen edge. If you are lucky, surface tension and the mount/specimen discontinuity will cause the paint to stop at the interface. Don't have too many cups of coffee before attempting this!
Woody White, McDermott Technology, Inc. http://www.mtiresearch.com
Also woody.white-at-worldnet.att.net http://www.geocities.com/capecanaveral/3722
A good source of belts of different types (and lots of other useful items) is the company:
Small Parts, Inc. 6891 N.E. Third Ave PO Box 381966 Miami, FL 33238-1966 305-751-0856
You should be able to find their catalog in your local machine shop. They have round polycord belts that can be cut to length and melted together, timing belts, and viton and Buna-N o-rings.
Hope this helps, Louie
At 3:46 PM -0600 11/12/97, Laura Rhoads wrote: } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America
Louie Kerr Research and Education Support Coordinator Marine Biological Laboratory 7 MBL Street Woods Hole, MA 02543 508-289-7273 508-540-6902 (FAX)
Salzburg, 14th Nov.1997 Dear Joan, I saw your posting and from the "Conc:" I know you are dealing with = Epon-Araldite sections (hydrophobic resin) to be stained with H&E (which stains well = on=20 deparaffinized sections, but more/less no staining on hydrophobic resins = is achievable). I do not know for which purpose it should/must be H&E = (maybe I could=20 offer you alternative staining methods),=20 but eventually 2 methods maybe will be successful:
1st one I didn=B4t test as yet (but if o.k., it would be a short and = elegant way): (I=B4m not sure about the reactions on the araldite component of your = resin mixture)
prerequisite: resin sections should adhere very strongly to the slide: = be sure that=20 sections are "glued" properly by heat (approx. 100-140 degr. C) by means = of a hot plate without folds.
Try: - Oxidize the sections (e.g. 1 -2% KMnO4 in A.bidest) for 2-5 min - wash by jet-stream (A.bidest) thoroughly the sections now will exhibit brownish to brown appearance (KMnO) - Bleach by 0.5 to 1.0 % Oxalic acid (in a. bidest) for at least 3-5 = min, move/gentle agitate your slide at some time within this incub.time. The sections have to be totally decolorized, maybe bleach a minute=20 or so more to be sure, no KMnO is within your section. - Jet stream washing (or slide incubation in a coplin jar, change at = least 2-3 times) - you don=B4t have to let dry the sections - try to stain with H&E. Maybe there is a staining effect (hopefully; = maybe it depends on the polymerization quality of your sections, the = thickness, the concentration/time of oxidation (solution) etc.......). IF NOT: -you have to remove, at least in part, resin components of your = sections: - you have to use protocols like saturated Na-or K-MetOH (Na-or K-methylate) or=20 saturated Na-or K-EtOH (Na- or K-ethylate) (receipts of LANE and EUROPA, 1960ies or so.....100 years ago) that means: oversaturated solution of absolute methanol or ethanol by=20 adding NaOH- or KOH pastilles more than the solution product is. Let stand in a brown lab glass flask (plastic stopper!!) about 2-3 = days. The overlaying phase turns more and more to a brown color. Don=B4t = swurl up the solution when handling flask for removal of solute! BE CAREFUL in PIPETTING the SOLUTE because IT IS STRONGLY = CORROSIVE!! Place one to two drops of the "Etching solution" (Na-/K-methylate = or ethyl- ate) unto the sections and let "work" for 1-3 min (you have to = test; depends on the section thickness, polymerization quality, bla, bla....) After incubation (please be aware of the corrosive properties: = shield eyes, fingers, etc.) jet-wash with absolute MetOH or EtOH, respectively. Do this washing vigorously/thoroughly/extended (since highly = alkaline solu- tions stick a long time on a glass surface or elsewhere!) If your sections adhere until that step, you=B4ll be lucky! Best then would be jet-washing (or even incubation into a coplin = jar) by=20 say 70% or 50% MetOH or EtOH, then down into a. bidest. Let stand = a while and be sure about no alkaline etching solution has remained = on your=20 section or slide. Then try H&E. Maybe this will yield sufficient staining for the = purpose you intended. Would greatly appreciate receiving a short note on the background = of using H&E on your EPON/ARALDITE sections.
Hope this helps best regards
Dr. Wolfgang MUSS Department of Pathology, LKA EM-Laboratory Muellner Hauptstrasse 48 A-5020 SALZBURG AUSTRIA/Europe
phone: ++43++ 662 + 4482 + 4720 Ext fax: ++43++ 662 + 4482 + 882 Ext. e-mail: W.Muss-at-lkasbg.gv.at (note: "l" right to "-at-" is a small "L")
---------- Von: Joan Clark[SMTP:j.clark-at-zoology.unimelb.edu.au] Gesendet: Freitag, 14. November 1997 16:15 An: Microscopy-at-sparc5.microscopy.com Betreff: Q: H & E staining of epon araldite sections - help needed
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Does anyone have a method for the H and & E staining of resin sections. = I would appreciate any methods or references TIA Joan Clark
Many thanks for the helpful replies after my recent inquiry about conductive epoxies for SEM specimen embedding. I am passing on the replies for other listmembers who may have an interest in this.
From Mark Darus:
} I use "PolyFast" available from Struers. The description on } the container states; Phenolic hot mounting resin with carbon filler } for edge retention and examination in SEM. } A code on the container is: FAPSA } 40100036 } 6062-5754 } Look in a Struers catalog for more information, or call them for one } at 1-888-Struers. }
From Matthew Libera:
} I had a similar problem when I was a grad student. I used conductive } epoxies from a company called Epotek in Billerica, Massachusetts. I } never had great success getting the conductive epoxy to cure properly, } however. Perhaps you will have more success. } } } From Phil Oshel:
} Various companies make silver-impregnated epoxy for making conductive } joins--such as gluing a new target onto an (old) Hummer sputter-coater } electrode. Don't know if this would work directly for embedding, but it } suggests that you could buy silver painting for mounting specimens that's } dissolved in acetone (EMS sells this, I think, others likely do also), and } use it in the embedding resin.
From Winton Cornell:
} what about simply mixing graphite into the epoxy as it's prepared? } } From Brian Demczyk:
} Yes, there most certainly are conductive epoxies (containing, for example, } silver). Check any of the EM supply houses. You might also want to check out a company called EPON-Tek, or something } of the like. } } From John Hunt:
} } Sure. Buehler and probably Struers, LECO etc. make conductive } material for mounts. The copper ones were removed from the market } some years ago but Al filled and Carbon filled ones are still } available, I believe. The powder is used in a hot hydraulic ram type } mold. The specimen is placed with the side of interest face down. The } mounts are usually inch or inch and a quarter diameter. The sample } is then ready for polishing. Coating is not necessary unless the } sampled is non-conductive in which case one might as well use epoxy. }
From Eunsung Park:
} I usually use a Ag-dispersed epoxy (from SPI) to embed small specimens } for both SEM and TEM work. Howver, it doesn't eliminate the necessity of } conductive coating since the epoxy contains non-conducting polymers. Another } problem is that the eopxy is not cheap (I fon't have the price list in handy). } It is surely worth to try, though. Good luck. }
From Warren Straszheim:
} We used to use some copper-filled diallyl pthallate (sp?) to embed coal. It } was a hot-preesed, thermosetting material from Beuhler or Leco. However, } there was still a substantial fraction of the surface that was } nonconductive. I don't recall if we could count on it providing a conducting } path to ground. I think we C-coated most of our samples anyway. } } At that time I was looking at S in coal and had little trouble from the C } coating. } } From Michael Cinibulk:
} } Epoxy Technology, Inc. manufactures a complete spectrum of epoxies } including at least four that are electrically conductive; all contain } silver. I have not used any of them myself. BTW, their EPO-TEK 353ND is } the same as Gatan's G-1, which I do use. } } Call them at 800 227 2201 for a catalog. } } From Scott Schwinge:
} Acme Conductive Adhesives (Division of Allied Products Corp. / New Haven, } CT) used to sell a product called "E-Solder No. 3022," which is a } conductive epoxy containing silver. It was intended as a substitute for } solder in electronics repair when soldering isn't possible. I haven't } used it for SEM. Hope this is helpful. }
From Hermann Reese:
} Allied High Tech Products has a Conductive Mounting Powder (order # } 169-10005) with carbon particles. } Allied High Tech (800) 950-9347 or (310) 635-2466 } } or } } Electron Microscopy Sciences has a Conductive Cold Mount (# 50452-01) with } copper particles. } EMS (800) 523-5874 or (215) 646-1566 } } } "I have no commercial or financial interest in the companies stated above, } except within Mexico." } } From Witold Zielinski:
} Well, this is maybe not exactly an unswer which one may excpect, } but it may give an idea how to deal with the problem. } We are using old electric discharge machine and it requires from } time to time the samples to be glued. So to make, the glue or } epoxy conaductive some carbone powder is add. } }
This is what I have received to date. Thanks to all and my apologies if I missed anybody.
Randy Tindall Electron Microscope Laboratory Box 3EML New Mexico State University Las Cruces, NM 88003
Only one addition to complete: the actual EIDE Bus ("DMA33")has a throughput of 33MB/sec and is thus nearly as fast as UW-SCSI and also has many of the features before only given by SCSI (less processor-power usage etc.)
Richard E. Edelmann wrote: Things to keep in mind with these numbers (1) you'll never see these speeds in reality - they are all determined in ideal situations not real world usage, but they are comparable with each other; (2) Actual transfer rates will vary depending on the interface used (i.e. the max. throughputs for the interfaces are EIDE (1-10MB/sec) vs SCSI (5-10MB/sec) vs SCSI-Wide (20MB/Sec) vs SCSI-UltraWide (40MB/Sec) vs parallel ports ( {1 vs Fiber Coupling (a.k.a. Fire Wire, 100+MB/Sec), (3) System configuration will also effect this; i.e. what CPU, what BUS speed, how much memory (RAM) what other components are in the system, what operating system, etc. , (4)
Dr. Arthur Schuessler University of Heidelberg Zellenlehre D-69120 Heidelberg Germany
since we have a serious problem with immunofluorescence, I hope somebody can help us. We used 0.5 and 1 micron sections of Unicryl embedded plant tissues for immunofluorescence. Sections were cut with an diamond knife / ultracut on water. We did labelings with second Antibodies (anti-rabbit) conjugated to FITC or Cy3. Once we had nice pictures, but 10 times we had --} } } } horrible spots ("stars") as background all over the regions the incubation drop was located, and very weak labeling. Also there are fluorescing droplets when using Cy3, I wonder if it is not ok. However, the FITC conjugated also shows the "stars". It really looks very bad - all is full of "dirt".
What could be the reason? In controls without first antibody the sections are always clean. We use TBS with 0.1 or 1% Casein, polylysin coated or uncoated coverslips, heat dried or not heated etc. With no first antibody always no stars. Is the antigen floating around?
Thanks a lot if there are any ideas ... Arthur Dr. Arthur Schuessler University of Heidelberg Zellenlehre D-69120 Heidelberg Germany
We are trying to evaluate a number of dimpler grinders for both plan view and cross-section TEM specimens and would like the opinion of people who might have used the models put out by the following 2 companies: VCR Group (Model 500i) and EA Fischione (Model 2000). These can be compared with the Gatan model (656) if the person has experience with those as well.
--
---------------------------------------------------------------- Mukul KUMAR, PhD Dept. of Mechanical Engineering Phone: (410) 516-8284 The Johns Hopkins University Fax: (410) 516-4316 3400, N. Charles St. E-Mail: mukul-at-jhu.edu Baltimore, MD 21218-2686 ----------------------------------------------------------------
Dear Lewis, } } I need a positive charge on formvar and or carbon coated copper grids. Any } suggestions or references would be appreciated. } Poly-l-lysine should do the job (unless you are going to apply a *very* high pH specimen). Just put a few microliters of 0.1% aqueous solution on the grid and air-dry. Good luck. Yours, Bill Tivol
Greetings, FWIW, I use either isopropyl based colloidal graphite or silver paint mixed 1:1 as a slurry with Duco household cement to affix samples to SEM stubs. It's not epoxy but it dries quickly, provides good conductivity and is easily scraped off to re-use stubs.
cheers ed
Edward J. Basgall, PhD The Pennsylvania State University Surface Chemistry Group ejb11-at-psu.edu Materials Research Institute Building Ph: 814-865-0493 University Park, PA 16802-7003 FAX: 814-863-0618 http://www.personal.psu.edu/ejb11/ Privilege does not absolve one of ecological responsibility.
I agree with Stephen Griffiths reply and would like to see this thread kept open a little longer. Most of the biological types have acquired some sort of allergy or dermatitis along the way if they have been in the field for any period of time, and those who haven't need to be reminded that the three most important assets a microscopist has is their brain, eyes, and hands. Without all of these, you can no longer ply your trade. The "chapped hand" syndrome is not trivial, the skin is a line of defense for chemical and for pathogens, once broken, both are free to penetrate. I would reinforce use of proper gloving as a way to avoid major problems in the future for those whose hands haven't gone by the way. In addition, I would like to remind that we are liable for what happens to our subordinates and severe dermatitis can, in fact, be a handicap if it limits range of motion. Like most, Lowicryl started my dermatitis, although I noticed the effects within months of first starting to use it. Little seems to help. Superglue and Eucerin are my mainstays. I would like to thank James Martin for asking the question as well as those who responded. I have been looking over the pharmacy shelves, picking up some of the suggested remedies to try.
Dear James, I have experience with penetration of glues, preservatives, etc. into wood, and the best label was bromide. This shows up well in EDX, is completely soluble and you can brominate most organic compounds quite well. We also used it the trace the movement of epoxy resin in prepreg layup parts (composite materials). Brominate the consolidant, then trace the presence of bromine with an EDX linescan or careful P/B analysis of bromine. It works equally well in TEM for individual wood cell wall layers (brominate the lignin) or SEM for overall penetration depths. You wrote: } A student will be assessing the penetration of various adhesive } consolidants into egg tempera based paint layers. The consolidants would } likely include animal glue, cellulosic ethers, and acrylics. } } She has considered tagging the consolidant with one or more dyes to allow } visual microscopic examination of depth penetration in samples cut in } cross-section. Another means of assessing penetration would be micro-FTIR } step-scan analysis of bulk cross-sections or thin-sections (1-5 microns). } } Here's a question for the TEM folk on the list. Can anyone think of a } feasible way to dope the consolidants with a metal(s) to allow mapping of } depth penetration by SEM-EDS, TEM, or another technique? } } I have only a limited knowledge of the use of metal-labelled antibodies to } mark specific antigens using EM, and know this application I describe is } quite different. } } Thanks for your assistance with this inquiry. } } James Martin Regards, Mary Mager Electron Microscopist Metals and Materials Engineering University of British Columbia 6350 Stores Road Vancouver, B.C. V6T 1Z4 CANADA tel: 604-822-5648 fax: 604-822-3619 e-mail: mager-at-interchg.ubc.ca
Dear Randy, I have used the conductive cold-curing resin: "Technovit 5000" for several years, but the last time I tried, my usual suppliers no longer carried it. Electron Beam Sciences Inc. informed me that they have it available, when I asked on the listserver. Several other suppliers of mounting media have hot-press, conductive mounting media (Leco, etc.). For my usual metallurgical mounts, I mount in normal epoxy, poloish, then paint all of the top epoxy surface with carbon paint, overlapping the metal slightly. Then run a stripe down the side to the stub to connect. I use the carbon evaporative coating if I want to look at the very edge of the sample or if the sample is not conductive, and only use the conductive resin if the sample cannot be coated and the edge is important. You wrote: } } Hi, } } Yet another question from the unpredictable world of multi-user facilities. } One of our users embeds samples in epoxy and polishes them to eliminate } topographical variables. He requires both imaging and EDS, which precludes } metal coating for conductivity. } } He was wondering about the availability of epoxies containing conductive } components, which might allow us to use high-vacuum SEM with secondary } electron imaging. Does such a thing exist? Has anyone ever used a } standard epoxy and added their own conductive "secret recipes" before } polymerizing? } } I'm aware that carbon coating is an option, as well as painting conductive } stripes of colloidal carbon or silver to the edge of the embedded materials } and down to the aluminum stub. The idea of a conductive epoxy is } intriguing, though, for the time and mess-saving possibilities. } } As usual, thanks in advance for the always helpful replies I get to these } queries. } } } Randy Tindall } Electron Microscope Laboratory } Box 3EML } New Mexico State University } Las Cruces, NM 88003 } Regards,
Mary Mager Electron Microscopist Metals and Materials Engineering University of British Columbia 6350 Stores Road Vancouver, B.C. V6T 1Z4 CANADA tel: 604-822-5648 fax: 604-822-3619 e-mail: mager-at-interchg.ubc.ca
Dear Listserver Readers, I note with interest that a competitor (Evex Analytical) has registered the following URL: http://www.thomson-scientific.com/ for their own use.
As a director of Thomson Scientific Instruments Pty Ltd I wish to state quite categorically that this company is in no way associated with us. Our website is in fact located at: http://www.werple.net.au/~tsi/
I shall leave it up to readers to make their own judgment regarding the ethics of Evex Analyticals action.
Thank you,
Paul Thomson Technical Director Thomson Scientific Instruments http://werple.net.au/~tsi/
We have a Zeiss 902 filter scope for sale. 6 years old. In excellent condition. Asking 28K. Will also deliver to your location. Presently on West coast. Call 732- 370-8082 for info.
What is the actual formula Sorensen used to make Sorensen's phosphate buffer? Not what you think it is, but What Dr. Sorensen stated in his paper in 1909, and what many of us have or thought we have been referencing for the past 88 years.
Some references say (Hayat) to use sodium phosphate and Potassium phosphate
Most other references state Sorensens Phosphate buffer has being made with sodium monobasic and sodium dibasic salts.
If anyone has the original reference to sorensens (biochem, 22, 253, 1909) on hand, I would be most appreciative if they would be kind enough to email or fax it to me.
Thanks in advance Gregory Argentieri Novartis Pharmaceuticals Corp 59 Rt 10 East Hanover, NJ 07936
Master Bond EP 75 is a graphite filled room temp setting, two part epoxy which is electrically conductive. It is rated at 50 ohm/cm, but I measure about 10k ohms/cm.
Metal particles cast and polished in this material show no charging when imaged at fast or slow rates in BSE or SE mode in my SEMQ. Nice to see the original colors of a material through the light optics. X-ray count rates seem OK.
It may be suitable for high vacuum since it contains no solvents. I can't volatilize a hole in the stuff even with a 100 nA focused beam.
Adhesion is excellent. In fact, it sticks to silastic mold perimeters.
Mixing is a little fussy. 3 parts to 100. A perfect mix might get the 50 ohm/cm value. Shelf life is supposed to be less than a year and it's expensive.
The grain size of the carbon filler is relatively coarse. Colloidal graphite might work better.
Master Bond is located in Hackensack, NJ. Phone 201 343 8983.
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Question/debate of the day:
What is the actual formula Sorensen used to make Sorensen's phosphate buffer? Not what you think it is, but What Dr. Sorensen stated in his paper in 1909, and what many of us have or thought we have been referencing for the past 88 years.
Some references say (Hayat) to use sodium phosphate and Potassium phosphate
Most other references state Sorensens Phosphate buffer has being made with sodium monobasic and sodium dibasic salts.
If anyone has the original reference to sorensens (biochem, 22, 253, 1909) on hand, I would be most appreciative if they would be kind enough to email or fax it to me.
Thanks in advance Gregory Argentieri Novartis Pharmaceuticals Corp 59 Rt 10 East Hanover, NJ 07936
------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America
Master Bond EP 75 is a graphite filled room temp setting, two part epoxy which is electrically conductive. It is rated at 50 ohm/cm, but I measure about 10k ohms/cm.
Metal particles cast and polished in this material show no charging when imaged at fast or slow rates in BSE or SE mode in my SEMQ. Nice to see the original colors of a material through the light optics. X-ray count rates seem OK.
It may be suitable for high vacuum since it contains no solvents. I can't volatilize a hole in the stuff even with a 100 nA focused beam.
Adhesion is excellent. In fact, it sticks to silastic mold perimeters.
Mixing is a little fussy. 3 parts to 100. A perfect mix might get the 50 ohm/cm value. Shelf life is supposed to be less than a year and it's expensive.
The grain size of the carbon filler is relatively coarse. Colloidal graphite might work better.
Master Bond is located in Hackensack, NJ. Phone 201 343 8983.
------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America
------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America
Question/debate of the day:
What is the actual formula Sorensen used to make Sorensen's phosphate buffer? Not what you think it is, but What Dr. Sorensen stated in his paper in 1909, and what many of us have or thought we have been referencing for the past 88 years.
Some references say (Hayat) to use sodium phosphate and Potassium phosphate
Most other references state Sorensens Phosphate buffer has being made with sodium monobasic and sodium dibasic salts.
If anyone has the original reference to sorensens (biochem, 22, 253, 1909) on hand, I would be most appreciative if they would be kind enough to email or fax it to me.
Thanks in advance Gregory Argentieri Novartis Pharmaceuticals Corp 59 Rt 10 East Hanover, NJ 07936
------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America
------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America
Master Bond EP 75 is a graphite filled room temp setting, two part epoxy which is electrically conductive. It is rated at 50 ohm/cm, but I measure about 10k ohms/cm.
Metal particles cast and polished in this material show no charging when imaged at fast or slow rates in BSE or SE mode in my SEMQ. Nice to see the original colors of a material through the light optics. X-ray count rates seem OK.
It may be suitable for high vacuum since it contains no solvents. I can't volatilize a hole in the stuff even with a 100 nA focused beam.
Adhesion is excellent. In fact, it sticks to silastic mold perimeters.
Mixing is a little fussy. 3 parts to 100. A perfect mix might get the 50 ohm/cm value. Shelf life is supposed to be less than a year and it's expensive.
The grain size of the carbon filler is relatively coarse. Colloidal graphite might work better.
Master Bond is located in Hackensack, NJ. Phone 201 343 8983.
Yes I see the bouncing message. It is all coming from one host and I am attempting to contact the system adminstrator there a bit hard on a Sunday Morning.
I have temporairly disabled all mail to subscribers at that site and I hope that that will mitigate the problem in the short term.
After reading Paul Thomson's posting we have discovered that Evex Analytical is also using domain name www.mektech.com. Needless to say that Mektech Inc. was NOT, is NOT, nor will it ever be associated in any way with Evex Analytical. Mektech's true website is located at http://www.visionol.net/~mektech.
It is very regrettable that deception has been chosen as a tactic by an unscrupulous company claiming to serve the scientific community.
Mektech Inc. http://www.visionol.net/~mektech
-------------------------------- Paul Thomson wrote:
} Dear Listserver Readers, } I note with interest that a competitor (Evex Analytical) has registered } the following URL: http://www.thomson-scientific.com/ for their own use.
} As a director of Thomson Scientific Instruments Pty Ltd I wish to state } quite categorically that this company is in no way associated with us. Our } website is in fact located at: http://www.werple.net.au/~tsi/
} I shall leave it up to readers to make their own judgment regarding the } ethics of Evex Analyticals action.
Thomson Scientific is a wholly owned Research & Development subsidiary of Evex Analytical Inc.,
----------
Dear Listserver Readers, I note with interest that a competitor (Evex Analytical) has registered the following URL: http://www.thomson-scientific.com/ for their own use.
As a director of Thomson Scientific Instruments Pty Ltd I wish to state quite categorically that this company is in no way associated with us. Our website is in fact located at: http://www.werple.net.au/~tsi/
I shall leave it up to readers to make their own judgment regarding the ethics of Evex Analyticals action.
Thank you,
Paul Thomson Technical Director Thomson Scientific Instruments http://werple.net.au/~tsi/
At 14:15 14/11/97 -0400, you wrote: } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America
"The mounting of Macromolecules for Electron Microscopy with particular reference to surface phenomena and the treatment of support films by glow discharge"
Jacques DuBochet, Michael Groom, & Shirley Mueller-Neuteboom. 1982
in
Advances in Optical and Electron Microscopy Vol. 8
Barer & Cosslet eds. Academic Press
Mel Dickson President, Australian Society for Electron Microscopy Director, Electron Microscope Unit, University of New South Wales. Sydney NSW 2052 Australia
You know, there *is* some sort of legal redress for this. I'm not sure what it is, since I really didn't care about my own name (Yes, believe it or not, some guy in British Columbia bought up all the names of people who posted to a newsgroup I frequent. The domain "oliver.net" is owned, along with about 500 others, by a firm in Vancouver which markets email forwarding, I think).
If you are interested in looking further to see if others have your name, look at the internic site:
http://rs.internic.net/rs-internic.html and use the WhoIs function.
Here are some good sites re legal issues:
http://www.pitt.edu/~lawrev/58-4/articles/domain.htm (from the Pittsburgh Law Review) http://www.mindspring.com/~iprop/webdoc1.htm (a review of the NSI conflict resolution policy) http://rs.internic.net/domain-info/internic-domain-6.txt (the NSI document)
The Law Review Article is great. Here's an excerpt for the section on "squatters."
1. Squatters - Dilution to the "Rescue"
All the written decisions involving squatters involve one individual, Dennis Toeppen, who registered numerous trademarks of others as domain names, including "americanstandard.com," "panavision.com," "aircanada.com," and "yankeestadium.com."(367) In Panavision, the defendant registered plaintiff's trademark "Panavision" as a domain name, and used his WWW site to display an "aerial view[] of Pana, Illinois."(368) Toeppen demanded $13,000 to discontinue use of the domain name.(369)
The court found that Toeppen had violated state and federal anti-dilution statutes and ordered a preliminary injunction.(370) The marks, having been used since 1954, were in the eyes of the general public and producers, directors and movie studios, "famous" marks within the meaning of the act.(371) Toeppen's use of the domain name lessened the capacity of the mark to " 'identify and distinguish goods or services' " under the Dilution Act, and further diluted the mark by preventing Panavision from using its trademark verbatim as a domain name.(372)
...
and "parasites"
2. Parasites
a. Use of the Same Name Between Competitors - Infringement
Parasites who obtain a domain name corresponding to the trademark of a competitor will rightly be found liable for infringement.(390) In Comp Examiner Agency, Inc. v. Juris, Inc.,(391) the Central District of California granted a preliminary injunction against a defendant who used plaintiff's federally registered trademark as a domain name to "sell, distribute, advertise, and/or market its goods and services to Juris' target market of lawyers and law firms."(392) Although the court provided no explanation, its finding of trademark infringement under sections 32(1) and 43(a) of the Lanham Act is reasonable: the use of A's registered trademark by B to market the same products as A, to A's target market, is the paradigm of infringement and "passing off." The court enjoined the defendant from using "Juris" or any confusing variant; nonetheless, defendant was granted three months to continue using the domain name and web site to post a text-only referral notice to defendant's new site.(393)
On Sun, 16 Nov 1997, Mektech Inc. wrote:
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } } Dear readers, } } After reading Paul Thomson's posting we have discovered that Evex Analytical } is also using domain name www.mektech.com. Needless to say that Mektech } Inc. was NOT, is NOT, nor will it ever be associated in } any way with Evex Analytical. Mektech's true website is located at } http://www.visionol.net/~mektech. } } It is very regrettable that deception has been chosen as a tactic by an } unscrupulous company claiming } to serve the scientific community. } } } Mektech Inc. } http://www.visionol.net/~mektech } } -------------------------------- } Paul Thomson wrote: } } } Dear Listserver Readers, } } I note with interest that a competitor (Evex Analytical) has registered } } the following URL: http://www.thomson-scientific.com/ for their own use. } } } As a director of Thomson Scientific Instruments Pty Ltd I wish to state } } quite categorically that this company is in no way associated with us. Our } } website is in fact located at: http://www.werple.net.au/~tsi/ } } } I shall leave it up to readers to make their own judgment regarding the } } ethics of Evex Analyticals action. } }
} ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America } To Subscribe/Unsubscribe -- Send Email to ListServer-at-MSA.Microscopy.Com } -----------------------------------------------------------------------. } } Thomson Scientific is a wholly owned Research & Development subsidiary of Evex Analytical Inc., }
Interesting. No doubt Mektech is one also. How many of your "wholly-owned subsidiaries" "just happen" to be the names of competitors?
Just curious, of course. I'm sure your ethical stance is spotless.
Well, I really don't usually follow up on *myself*, but I went ahead and did a WhoIs on EVEX. It turns out that EVEX, happens to have registered the following names:
I would be interested in the going rates for typical TEM charges , from reception of the specimen to the generation of prints, irregardless of interpretation. Has anyone accurate costing information on this?
Best regards, Jerome Jasso Children's Hospital Medical Center of Akron (330) 379-8279
I wish to thank those three people who answered my request which I repeat below. All three pointed me to suppliers in the U.S. (which is a bit expensive due to postage) or to standard EM-suppliers but there I have only found boxes for biological standard size thin sections (the 76 mm long ones). I am really surprised that this German Company should have been the only one to provide boxes for 28x48 mm size. Or are there so few Europeans on the list??
} } Hello everybody, } a question to the mineralogists on the list: } as the German provider (Krantz) for storage boxes for mineralogical } standard thin sections cannot provide them any longer I am looking for some } other source, preferably in Europe. } What I call "standard thin sections" are 28 x 48 mm sized. } Thank you in advance } Hiltrud } } Dr. Hiltrud Mueller-Sigmund } Institut fuer Mineralogie, Petrologie und Geochemie } Albertstrasse 23b, 79104 Freiburg (Germany) } Tel.: (+49)-203-6388/-6396 Fax: -6407 } } } hiltrud-at-ruf.uni-freiburg.de (Hiltrud Mueller-Sigmund)
Dr. Hiltrud Mueller-Sigmund Institut fuer Mineralogie, Petrologie und Geochemie Albertstrasse 23b, 79104 Freiburg (Germany) Tel.: (+49)-203-6388/-6396 Fax: -6407
I wish to thank those three people who answered my request which I repeat below. All three pointed me to suppliers in the U.S. (which is a bit expensive due to postage) or to standard EM-suppliers but there I have only found boxes for biological standard size thin sections (the 76 mm long ones). I am really surprised that this German Company should have been the only one to provide boxes for 28x48 mm size. Or are there so few Europeans on the list??
} } Hello everybody, } a question to the mineralogists on the list: } as the German provider (Krantz) for storage boxes for mineralogical } standard thin sections cannot provide them any longer I am looking for some } other source, preferably in Europe. } What I call "standard thin sections" are 28 x 48 mm sized. } Thank you in advance } Hiltrud } } Dr. Hiltrud Mueller-Sigmund } Institut fuer Mineralogie, Petrologie und Geochemie } Albertstrasse 23b, 79104 Freiburg (Germany) } Tel.: (+49)-203-6388/-6396 Fax: -6407 } } } hiltrud-at-ruf.uni-freiburg.de (Hiltrud Mueller-Sigmund)
Dr. Hiltrud Mueller-Sigmund Institut fuer Mineralogie, Petrologie und Geochemie Albertstrasse 23b, 79104 Freiburg (Germany) Tel.: (+49)-203-6388/-6396 Fax: -6407
We are looking for antibodies against CD4 and CD8 that can be used with formalin fixed, paraffin embedded rat tissues - with or without application of antigen retrieval procedures. Has anybody some helpful experience ?
Thanks alot.
Heinz
**************************************************************************** Dr. Heinz Fehrenbach Institute of Pathology University Clinics "Carl Gustav Carus" Technical University of Dresden
What is the maximum tilt angle available onto the JEOL JEM 2010 FEG UHR (Ultra High Resolution)? The technical specs in the brochure give us +/- 25=B0? Is there any special TEM sample holder use to reach this values?
I am planning to do immunogold on brassica pollen grains. I am looking for an adhesive that remain tacky when dried and would hold pollen through out the process of washing, fixing, immuno-treatment, postfixing, dehydrating and critical point drying.
Any suggestions will be appreciated. Thanks.
Ann Fook Yang EM Unit, ECORC Agriculture and Agri-Food Canada, Central Experimental Farm, Ottawa, Ontario, Canada K1A 0C6
I'm trying to adapt a resin recipe for use in a processor. Right now, I'm adding 3%BDMA which gives a nice block but polymerizes too quickly. Will decreasing this to 2% slow this down a bit? Yes, I could spend the next 3 days experimenting but I'd like to get some material processed by the end of the week. Many thanks Grace
I would like to see some more conversation on this cost analysis thread.
I am in the middle of trying to justify hiring another tech to help me get out of this back log of work I'm into. The powers to be want me to determine how much time I spend working on each project and investigator. I am spending an exorberant amount of time doing this as I typically do multitasking of different steps on different samples for different investigators essentially at the same time. This they say will tell them what is taking up my time and what another tech would need to be hired for (I already know this info) . Even if I generate the numbers for them they have nothing to compare my workload with to say yes you have more samples coming in than you can take care of. As we know EM is very time consuming. I would like to see what volume of work other department run (but service for entire campus) facilities are producing vs the number of techs producing that work. And because some places may have advanced equipment, it should be limited to producing standard blocks and negative staining techniques. Would any facilities like to help me out on this?
My technique for the cost analysis was to break up the service costs into major steps: processing and embedding, survey sections, thin sections, and scope time. Each step was divided into cost of: materials, and labor, per sample or block where I timed my self performing each step on average. There was also a category for specialized techniques and training of students or others.
Maybe this type of material could be a tutorial or subject at a future MSA meeting ? I was unable to go to the last one that had a round table on facility management (Cincinnati ?). Was this information discussed ?
People looking for costs on equipment should look up the Technologist Forum's Facilities and Equipment list that is available. Thanks for any advice out there.
Rick Vaughn
Electron Microscopy Research Facility Dept Cell Biology & Anatomy Univ Neb Med Ctr RLVAUGHN-at-MAIL.UNMC.EDU
Does anyone still sell the Zero-Stat gun? If anyone has any information on where I can purchase one or if it's still on the market please let me know. Thank you for your help.
Laura L. Estok M.E. Taylor Engineering, Inc. 21604 Gentry Lane Brookeville, MD 20833 Phone: 301-774-6246 * FAX: 301-774-6711 * e-mail: Metengr-at-aol.com
That still doesn't answer the question as to why the other web sites take me directly to the EVEX page. It may not be an intentional deception since I am aware that you service other manufacturers' equipment. But it sure pushes the envelope of what is proper.
At 10:25 AM 11/17/97 -0500, you wrote: } ------------------------------------------------------------------------ } The Microscopy ListServer -- Sponsor: The Microscopy Society of America
This looks like a job for activity based costing (ABC) analysis. I suggest that you see if any of your school's accounting students (or professors) need a project. ABC accounting can be fairly complicated for a large organization, but your situation seems manageable enough for a small project team. A broad outline is as follows: list the activities each person does (including non-value-added time such as waiting for results!) with the percentage of time spent on each activity, then divide each person's fully loaded salary by the time spent on each activity (everything should total 100%), then add the costs for each activity. At this point you will have a pretty good estimate of what it costs for each activity. Then map (flowchart) the process including all decision points to show where the money goes and why. From this point, standard TQM tools (storyboarding, Pareto analysis, etc.) can be used to improve the process. It's a lot of work, but if you need to argue a case for more money, the powers that be need something they can see, with dollar signs attached. As far as backlog cost calculations, try to find out from the customer what is not being done (i.e. projects not completed, papers not completed, etc.) and their best estimate on how much their time is worth.
I think if you approach the powers that be on the premise that the objective is not to increase costs by hiring a tech, but rather to improve customer service by allowing the process improvements pay for the tech, then you will have a better chance of getting support. If somebody in a position of power can gather support for the cross-functional effort involved in such a project, then their reputation will be enhanced as well. You could conceivably get the tech you know you need, make your leaders look good, get free/low-cost accounting help (without you doing all the work), employ a deserving technician, help an accounting student get valuable process improvement experience, reduce your backlog, and improve your service to customers. Win/win all around.
my two cent.
------------------------------------------------ Opinions or statements expressed herein, rational or otherwise, do not necessarily reflect those of my employer.
Harold J. Crossman OSRAM SYLVANIA INC. Lighting Research Center 71 Cherry Hill Dr. Beverly, MA 01915 Phone: (508) 750-1717 E-mail: crossman-at-osi.sylvania.com
Our web sites: www.sylvania.com www.siemens.com --
When I attempted to reach the IXRF website several months ago, I found myself staring in disbelief at the Evex web page. Thinking I must be totally stupid, I retyped the web address "www.ixrf.com" into Netscape, and there it was again, the Evex web page. At first it reflected badly on the IXRF name, to me.
This was confirmed by Kenny Witherspoon at IXRF, who lamented that they essentially lost their site name to Evex, because one can officially license a site name now, and IXRF had not done so. It is my understanding that Evex scarfed "www.ixrf.com" that was already in use. (To reach IXRF' web page you have to use www.ixrfsystems.com, by the way)
Does Evex claim to represent IXRF, sell IXRF products, etc. What is the story?
Just what does "Evex" mean anyway? As in (K)evex?
Anyways, customers find deceptive strategies similar to this to be a real turn-off, and when they are purchasing equipment, they wonder how this reflects on issues related to service, repair, etc. It is poor business practice and doesn't fool anybody in the end.
Dear Gregory, are you quite sure about your question which seems to be really a = centennial question ??? I made my lession now and the passed 2 hours in studying a lot of = ("old") literature (originals starting in the late 50ies) as well as textbooks of = histology, EM etc.,=20 etc....This problem amazed me since I had a personal question about this = when starting my "carrier" as Electron Microscopist in 1981: you are right in = that there are variable formulas in mixing up "Soerensen=B4s" Buffer solution: sodium = and potassium phosphate (basic, acid) as well as sodium (acid) and sodium (basic) on = the other hand (as well, might be, other substances).
Unfortunately I don=B4t have at hand Soerensen=B4s original paper. If = this is a *must* for you, I could try to get the original publications, since they are = written in "German" journals of the turn of the 19th to 20th century and therefore my be = available more likely in Austrian or German libraries (please let me know).
Follows now a Sherlock Holmes story (maybe only a story by his = assistent, whose name unfortunately I don=B4t remember now):
I didn=B4t read, but had a short "insight" to appr. 10 textbooks of = histology, histo- chemistry, etc., incl. PEARSE A.G.E.(Ed) Histochemistry Theoretical and = Applied, Vol. 1: Preparative and Optical Technology, CHURCHILL-LIVINGSTONE, 4th = Ed,=20 1980 (see p. 236: BUFFERS: pH 5.29 to 8.04: Soerensen (1909-12): Na2HPO4 =
0.06M and KH2PO4 0.06M-mixture) since other book and paper sources = quoted PEARSE (1953) as reference. Unfortunately PEARSE did NOT include a = bibliographic reference for that formula, but, in fact, he mentioned = "1909-12"; o.k. next step: Another paper cited: "Soerensen=B4s phosphate buffer, adapted from = LILLIE and=20 FULLMER ( Histopathologic Technic and Practical Histochemistry, 4th Ed., =
McGRAW-HILL Book Company, 1976)": there I found in Chapter 20: "Buffers and Buffer Tables", p. 878 the = following: } } Table 20-12: Soerensen=B4s phosphate"s" *(ref. for foot note): "the = mixtures on this page were made by P. Jones, and read electrometrically on a Beckman = pH-meter.=20 Readings are corrected to 25 degr. C and slightly smoothed. Phosphate = buffer*s*=20 above 8 and below 5.3 are considered unreliable for histologic use, and = readings are omitted. { { The given formulas in the table are:
Left side: "Dry salt mixtures for field use* (ref. to footnote:): = follows amounts in=20 milligrams of Na2HPO4 + *NaH2PO4.H2O* as well as Na2HPO4 + *KH2PO4*=20 (different milligrams for different pH-values ranging from 5.3 to 8.0). = The footnote pays attention to "The dry salt mixtures calculated from Soerensen=B4s 0.067 = M data. They=20 are to be dissolved in rain water at 1% concentration, ca. 0.070M; if = higher dilutions are used, pH values may be approximated by the following table":
follows grams and milligrams per liter for 0.1 M, 0.067 M and 5 mM, = respectively.
Right side of Table 20-12: } } *Phosphates* at 0.1M, 0.067 M and 5 mM { { The table consists of 5 rows of data: first row (1): second row (2): pH values at specified dilutions (row = 3-5):
In that Chapter 20 a lot of Buffer Formula=B4s one can find. Some = formulas are referenced solitary like: "Gomori(Goemori):personal communication, = ....unpublished" etc. As Main References there are given: W. M. CLARK (Ed): "The determination of Hydrogen Ions", 3rd Ed., = Williams=20 & Wilkins, Baltimore, 1928, and A.G.E.PEARSE (Ed):Histochemistry, 2nd = ed., Little Brown, Boston, 1960. Unfortunately: NO direct reference to an ORIGINAL PAPER of Soerensen.
Therefore: another book:
PERRIN D.D., DEMPSEY B. (Eds): Buffers for pH and Metal Ion Control: = SCIENCE=20 PAPERBACKS # 157 (Chapman & Hall, London, N.Y.), 1974 (1st ed., maybe = there=20 is a newer one now) approx. 180 pp, incl. subject index. Searching the subject index: for } } Soerensen { {: only "Soerensen p*s*H scale" (p. 26) is mentioned: mentioned there (after a statement what the usual standards for = pH-measurement are: (0.05M) K-hydrogen phalate- and (0.01M) Na-borate-buffers and what = "strictly=20 the standards of the US NBS are based on (molalities/moles per kg = solvent) and the=20 British standards are based on (molarity/moles per litre of solution)" = and some=20 information on the concentration vs. buffer capacity there follows a = next paragraph } } Buffer values on "the original Soerensen "p*s*H" scale" can be = converted=20 approximately to the agreed standard scale *by adding 0.04* { {
No word more about *Soerensen* or *Soerensen psH-scale": I checked the = text of the whole book on another quoting of a hint on Soerensen: = nothing.
Next: searching for } } phosphate buffers" { {:=20 references to p. 27: "The pH 7.4 phosphate buffer given in Table 3.3 = (p.41) is useful=20 as a reference in measuring the pH of blood..."...... nothing about=20
*Soerensen*....because Table 3.3. p 41 is entitled: NBS phosphate = buffers as pH=20 standards* (*footnote: BATES 1962): it consists of given mixtures "Soln. = I" and "Soln II", whereby "Soln I" is given as } } 0.025 M KH2PO4 (3.388g) and 0.025M = Na2HPO4 (3.533g) in 1 l of solution at 25 degr.C { { and "Soln II" is given as } } = 0.00869M=20 KH2PO4 (1.179g) and 0.0304 M Na2HPO4 (4.302 g), in 1 l of solution at 25 =
degr.C { {. These solutions at different degrees C make different ranging = pH-values =20 for 0-95 degr. C for Soln I, and 0- 50 degr. C for Soln II, resp.=20 Nothing more about *Soerensen*.
Without notice in the subject index: Table 3.15 (p.53, but indexed by = "phosphate=20 buffers"): } } pH values of isotonic Soerensen*(footnote) buffers+(footnote) { {: =20
The formula uses "Na2HPO4 and NaH2PO4.H2O or NaH2PO4.2H2O, respectively, the final mixture also containing NaCl (mg/100 ml) to adjust the = tonicity to 0.92 at 37 degr.C". pH values are given for 25 degr.C as = well as for 37 degr.C and differ at same=20 pH levels/mixtures in the range 0.01 - 0.02 (e.g. pH -at- 25 degr.C =3D = 5.76, -at- 37 degr. C =3D 5.74; -at- 80 degr.C. 7.33, -at- 37 degr. C 7.32) footnote *: refers to SOERENSEN (1909), footnote "+": mentions CUTIE &=20 SCIARRONE (1969): No hint on "KH2PO4 and/or Na2HPO4......."
Next step: searching the "references index" for "Soerensen": uncredible, = there it is: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!= !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!= !!!!!!!!!!!
Soerensen (1909): no title, "Biochem. Zeits." (which means "Biochemische =
Zeitschrift"), *21*, p. 131 & !!!!!!!!!!!BUT!!!!!!!!!!!!
there is another reference too:
Soerensen (1912), no title, "Ergebn.Physiol." (which means "Ergebnisse = [in] der=20 Physiologie"),*12*, p. 393 &
Now I thought that there had to be another, second "Soerensen" reference = within the=20 text or tables. Subject index for "phosphate buffers" in addition said: = p. 138, 139,=20 151:
} } For disodium hydrogen citrate, NaOH, HCl buffers covering the pH = range 2.2 -=20 6.8, see *Soerensen (1909, 1912)* { {
Got it.
So at the end, despite not owning the original papers of Soerensen, I = think those=20 must be experimental papers dealing with concentrations, temperatures, = dilutions,=20 diverse buffer substances (according to PERRIN/DEMPSEY 1974, p. 1, the = term=20 "buffering" was created by FERNBACH and HUBERT 1900, cf. Compt. rend. = *131*,=20 p 293 &) and the so called "psH" -scale of Soerensen is most probably a = protocol of=20 his measurements, dealing also with a variety of phosphates (at least K- = and Na- PO4), which sometimes is referred to as "Soerensen=B4s buffer" for = sympathetic, "historical", "respectful" or "ancient" reasons, but still = is 0.1 M or 0.067 M or =20 0.005 M buffer (see above) exhibiting slight modifications in pH and = maybe in buffer=20 capacity by concentrations as well as temperature. Some authors=B4 tables or their infos I went through state there is no = or even little=20 difference in using Na-Phosphates instead of K-Phosphates, provided that = the molar ratios are kept.
So I wouldn=B4t worry about either *Na-Na-PO4* or *KPO4 -NaPO4* = ingredients. Most important conditions for me are buffer capacity at a given = concentration and +/- isotonicity (which sometimes has to be increased = by adding substances like glucose, sucrose or even NaCl). I am using = Millonig=B4s 0.13M and 0.10M for buffering my specimens, osmication = and/or washing solutions. Millonig=B4s buffer solution is either prepared by mixing Na-Na-PO4 or also formulas using only NaH2PO4 = (acidic) and NaOH (basic, alkaline component; Formula, if wanted, on = request).
Just for completion of the reference list I give the reference for = GOMORI 1955,=20 because he was obviousely a very famous scientist and worker in that = field=20 (histochemistry and histochem. staining reactions), maybe that book is = more readily accessable to you (library) and you can find there valuable = informations:
GOMORI (1955): Methods in Enzymology *1*, p. 141 &.
Hope this helps, if I should have a look for getting those (certainly) "German written" = original papers (which will be a little bit difficult, but.....and it = will take some time to get it),=20 please don=B4t hesitate to send me your e-mail request.
Best regards to you and yours,=20 have a nice day
Dr. Wolfgang MUSS Department of Pathology, LKA EM-Laboratory Muellner Hauptstrasse 48 A-5020 SALZBURG AUSTRIA/Europe
phone: ++43++ 662 + 4482 + 4720 Ext fax: ++43++ 662 + 4482 + 882 Ext. e-mail: W.Muss-at-lkasbg.gv.at (note: "l" right to "-at-" is a small "L")=09
------------------------------------------------------------------------ The Microscopy ListServer -- Sponsor: The Microscopy Society of America=20
Question/debate of the day:
What is the actual formula Sorensen used to make Sorensen's = phosphate buffer? Not what you think it is, but What Dr. Sorensen stated in = his paper in 1909, and what many of us have or thought we have been referencing for the past 88 years.
Some references say (Hayat) to use sodium phosphate and Potassium phosphate
Most other references state Sorensens Phosphate buffer has being = made with sodium monobasic and sodium dibasic salts.
If anyone has the original reference to sorensens (biochem, 22, = 253, 1909) on hand, I would be most appreciative if they would be kind enough to email or fax it to me.
Thanks in advance Gregory Argentieri Novartis Pharmaceuticals Corp 59 Rt 10 East Hanover, NJ 07936
Dear Greg, unfortunately I found one data jam in my mail to you:
In the paragraph 8 lines above !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!= !!!! (followed by the original Soerensen references) instead of:
The formula uses "Na2HPO4 and NaH2PO4.H2O or NaH2PO4.2H2O, respectively, the final mixture also containing NaCl (mg/100 ml) to adjust the = tonicity to 0.92 at 37 degr.C". pH values are given for 25 degr.C as = well as for 37 degr.C and differ at same=20 pH levels/mixtures in the range 0.01 - 0.02 (e.g. pH -at- 25 degr.C =3D = 5.76, -at- 37 degr. C =3D 5.74;=20
-at- 80 degr.C. 7.33, -at- 37 degr. C 7.32)
footnote *: refers to SOERENSEN (1909), footnote "+": mentions CUTIE &=20 SCIARRONE (1969): No hint on "KH2PO4 and/or Na2HPO4......."
Next step: searching the "references index" for "Soerensen": uncredible, = there it is: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!= !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!= !!!!!!!!!!!
it should be read:
"-at- 25 degr. C. 7.33, -at- 37 degr. C. 7.32" Sorry! Bye W.