bluuebunny/crossref_metadata_2025 huggingface dataset:
Tracking Cells in Embryos
Authors: Carmichael Stephen W
Published: March 2018

Ever since the first embryo was put under a microscope, scientists have been trying to determine which embryonic cells form which structures in the mature organism. Classic methods were to kill (ablate) certain cells and see what structures were malformed or missing when the animal developed. More recently, cells have been labeled with visible tags and the tagged cells traced through development. One problem is that the tag gets diluted by half each time a labeled cell divides. A new labeling method that shows a lot of promise has been demonstrated by David Piston, Robert Summers, Susan Knobel, and John Morrill.
New Capabilities for the TEM: Automatic Orientation Measurement and Nanocrystal Grain Maps
Authors: Wright SI , Dingley DJ , Mainwaring PR
Published: March 2018

Orientation Imaging Microscopy (OIM) is a rapid and spatially specific technique for automatically measuring individual crystallographic orientations in a polycrystalline sample. The technique is based on electron backscatter diffraction in the scanning electron microscope (SEM). While the OIM technique has seen many applications to the investigation of structure/ property relationships in polycrystalline materials, with grain sizes ranging from millimeters to submicron, it is not easily applied to the characterization of microstructures at the nanometer scale due to the inherent resolution limitations of the SEM. Thus, a complementary technique for the transmission electron microscope (TEM) would be advantageous for the study of local orientation in submicron structures such as those that exist in nanocrystalline materials and deformed materials.
Imaging Software Helps NASA Explore Drug Development
Authors: Traino Rebecca
Published: March 2018

There are over 100,000 different proteins in the human body. Each of these proteins plays an important role, such as catalyzing reactions and fighting disease. Researchers at the National Aeronautics and Space Administration (NASA), are looking at the make-up of proteins that are linked to diseases, to lead to the formation of effective drugs to help battle AIDS, diabetes and cancer.

"We are studying the structure of the proteins and how the protein's structure affects its function," says Dr. Russell Judge, a researcher at NASA. "This research will eventually lead to the creation of a drug that interrupts harmful protein activities."

In order to determine the protein structure, scientists have to grow large uniform protein crystals, measure and count the crystals.
Strategies for Preventing Detachment of Sections from Glass Slides
Authors: Kiernan J A
Published: March 2018

A thin, flat section of animal or plant tissue will usually adhere to a clean glass surface and stay in place through the common preparative procedures of staining, washing, dehydration and clearing. The adhesion may be due largely to the close contact between two flat surfaces. This allows very weak non-ionic forces (such as van der Waals forces and hydrogen bonds) between individual atoms, to exist in numbers great enough to add up to a strong attraction between slide and section. Ionic attractions, which operate over longer distances, may also exist between the silicate of the glass (negatively charged ions, especially in an alkaline medium) and basic groups of proteins in the tissue (positive ions, especially in an acidic medium). Unfortunately, not all sections are perfectly flat and not all slides are perfectly clean. Even when these conditions are met, there are some staining techniques that are harsh enough to remove the flattest section from the cleanest slide.
So What Can be Done to Avoid Getting Cumulative Trauma Disorders?
Authors: Minshew Jan
Published: March 2018

The first article reporting the rising incidence of carpal tunnel syndrome in histotechnologists was written by Pearl Gervais and published in the Louisiana Society for Histotechnology newsletter in 1991. Following that article, the growing interest in the number of injuries within the profession prompted a nationwide survey of histotechnologists. The results of that survey appeared in the first part of a three part article published in the Journal of Histotechnology, 18:139,1995. The articles were written by a group of professionals from the University of Michigan. Carpal Tunnel Syndrome (CTS) was used as the model for potential Cumulative Trauma Disorder (CTD).
How to Calculate the Temperature Rise Due to Beam Heating
Authors: Tivol William F
Published: March 2018

The temperature of a specimen rises when the electron beam interacts with it, producing ionization and excitation of atoms and breaking molecular bonds. Energy loss in bulk materials is ultimately converted to heat, but for small particles some of the energy escapes. Of the energy lost by the electrons in the incident beam, that which is absorbed by the specimen and degraded to heat includes oscillations of valence electrons, the kinetic energy of low-energy secondary electrons, and radiationless recombination of ionized atoms or moiecuies. Energy not absorbed includes brehmsstrahlung, characteristic x-rays, and the kinetic energy of higher-energy secondary electrons. Glaeser (1979) estimated that 50% of the energy loss is confined to a distance of about 5 nm from the track of the incident electron, while the other 50% is largely due to secondary electrons having 0.5 to 5 keV kinetic energy.
Alcohol, Acetone and Propylene Oxide as Dehydrating Agents or Intermediate Solvents Prior to Epoxy Embedding of Biological Specimens
Authors: Crowley Hildegard H
Published: March 2018

Acetone, alcohol, and propylene oxide have different mechanical and chemical properties. They should not be chosen haphazardly but should be used with care to suit the particular demands of the embedding conditions.
Nanostructures Require Nanomeasurements
Authors: Carmichael Stephen W
Published: March 2018

Nanofabrication is upon us. But engineers require measurements of physical properties of their materials in order to use them appropriately. Because the size of the object is in the nanometer scale, tiny measuring devices are required. Furthermore, there is the problem of reading these tiny devices. Zhong Lin Wang, Philippe Poncharal, and Walter de Heer at Georgia Tech have solved this problem by using the transmission electron microscope (TEM) to read off the measurements.

A special device was designed to fit inside the TEM, allowing for simultaneous visualization and manipulation of a nanostmcture. The nanostructure that Wang ef al, used was the carbon nanotube which could be clearly visualized by the TEM and has a well-defined structure. Specifically, they used multiwalled nanotubes with diameters of 5 to 50 nm and lengths of 1 to 20 μm. The device they designed for in situ microscopy was a modified specimen holder that allowed carbon nanotubes to be mounted in a conducting medium and positioned across from a counter electrode, which was a droplet of mercury or gold/ platinum balls.
A Protocol for Authentication of Paintings
Authors: McCrone Walter C
Published: March 2018

Strictly speaking, it is impossible to authenticate any painting to the extent of naming the artist who produced that object. One can only increase the likelihood thereof. In one celebrated case I felt I had fully proved that Manets palette had indeed been used to paint a particular painting but a “scholar” on whose reaction the art world depends for final acceptance of authenticity only said “someone” could have borrowed Manets palette one fine day and painted that picture. In a second celebrated case I was able to prove, but not convince, the world that a particular painting (Shroud of Turin) was, in fact, a painting and not an artifact produced by some other mysterious means, e.g., some sort of photographic process or resurrection itself.
High Resolution Imaging Using Confocal and 2-photon Molecular Excitation Microscopy
Authors: Cannell MB , Soeller C
Published: March 2018

Fluorescence microscopy has proved to be an invaluable tool for biomedical science since it is possible to visualise small quantities of labelled materials (such as intracellular ions and proteins) in both fixed and living cells. However, the conventional wide field fluorescence microscope suffers from the disadvantage that objects outside the focal plane also fluoresce (in response to the excitation light) and this leads to a marked loss of contrast for objects in the focal plane. This is especially a problem when the fluorescent probe is distributed throughout the thickness of the cell and the cell is thicker than about 1 μm. The confocal microscope overcomes this problem by illuminating the preparation with a point source of excitation light and limiting the collection of light with a pinhole that is confocal with the illumination source. This converts the microscope from an imaging system to a point detector and images are produced by scanning the illuminating and detecting point over the specimen to build an image (in much the same way that a television set produces an image). The basic idea behind the confocal system is shown in Figure 1, and it should be noted that light from points outside the focal plane is defocused at the pinhole and so does not pass through the pinhole efficiently.
Getting Suspended Cells or Particles Embedded in the Tip of BEEM Capsules
Authors: Plowman Barbara
Published: March 2018

It can be a problem to get suspended (or plated) cells or particles to settle into the apex of a BEEM capsule for embedding, particularly if the cei is/particles can not be embedding in agar or gelatin for some reason. The following simple procedure solves this problem.

Process the suspensions in polypropylene test tubes or microcentrifugation tubes. These can be spun down after each transfer for 5 minutes at 3000 rpm. Once the cells/particles are fixed, en bloc stained, and infiltrated with either Spurr's or LR White resin, I transfer them to BEEM capsules. I do not add additional resin yet. These are placed piggyback in microcentrifuge tubes that have been slit with wire cutters to make them large enough for the BEEM capsules to fit (see following illustration).

Processing cell suspensions or plated cells can be done in polypropylene test tubes or microcentrifuge tubes. These can be spun down after each transfer for 5 minutes at 3000 rpm. Once the cells are fixed, enbloc stained, and infiltrated with either Spurr or LRWhite resin, I transfer them to BEEM capsules. I do not add additional resin yet.
Formaldehyde as a Fixative for Light and Electron Microscopy
Authors: Carson Freida L
Published: March 2018

Since Blum discovered its hardening properties in 1893, formaldehyde has become the most widely used fixative in the world for specimens to be examined by light microscopy. However, since most commercial preparations of formaldehyde contain methanol, a protein precipitant, formaldehyde has been considered an unsatisfactory fixative for tissues to be examined by electron microscopy. In 1973, Carson et al., described a parallel study comparing the electron microscopic results of fixation with paraformaidehyde vs. formaldehyde. They found that there was no difference in the preservation of ultrastructural morphology provided that the buffer systems were identical. In 1976, McDowell and Trump described a fixative combining commercial formaldehyde and glutaraldehyde (4CF-1G). Both of these fixatives are dual purpose fixatives and preclude the selection of tissue for electron microscopy prior to fixation. They can both be prepared in large quantities and used for routine surgical specimens. The fixative containing formaldehyde alone does not need to be refrigerated and is stable for months; whereas, the formaldehyde-glutaraldehyde mixture should be refrigerated.
Computer Microvision for MEMS
Authors: Freeman Dennis M
Published: March 2018

Computer Microvision is a microscopy technique originally developed to study sound-induced motions of sensory cells in the inner ear - motions that are on the order of picometers-i.e., smaller than the radius of a hydrogen atom. Three-dimensional micrornovies of inner ear cells moving in response to sound were analyzed to quantify motions with nanometer precision. Recently we have adapted the technique for in situ measurement of motions of micro-electron mechanical (MEMS) devices.

In Computer Microvision systems, images of MEMS are magnified with an optical microscope and projected onto a CCD camera. Stroboscopic illumination is used to obtain stopaction images of the moving structures. Stop-action images from multiple focal planes provide information about 3D structure and 3D motion. Image analysis algorithms determine motions of all visible structures with nanometer accuracy. The system can measure motions at frequencies as high as 5 MHz with nanometer resolution, i.e., well below the wavelength of light.
The WAIS and byways of the GOPHER
Authors: Revel Jean-Paul
Published: March 2018

The Gopher, although as industrious as the Beaver and the skilled architect of complex subterranean mazes which should inspire as much awe as the dams and lodges built by beavers, is rarely revered as the mascot of Institutes of Higher Education. In real life many, my wife and I included, relentlessly pursue the garden variety gopher who dares to intrude and destroy prized plants, or for that matter even plants we do not care about. It is my job to deal with them and I do it like a Daemon that's BinHex-ed. However there is a highly prized and very beneficial, if virtual, species of GOPHERS. These creatures, created at the U. of Minnesota (home of the Golden Gophers), put their tunneling ability to good use, digging out otherwise hard to find information and so performing great services on the latter day wonder of electronic communication, the Information Superhighway, the Internet.
Electron Sources: Past, Present, and Future
Authors: Joy David C
Published: March 2018

The electron source is the most important component of the Scanning Electron Microscope (SEM) since it is this which will determine the overall performance of the machine. The gun performance can be described in terms of quantities such as its brightness, its source size, its energy spread, and its stability and, depending on the chosen application, any of these factors may be the most significant one. The task of the electron gun in a SEM is, in fact, particularly difficult because of the very wide range of operational parameters that may be required, e.g. a variation in probe size of from a few angstroms to a few microns, and a probe current which may go from less than a pico-amp. to more than a microamp. This wide range of operating parameters makes the choice of the optimum source for scanning microscopy a difficult decision.
Networking Solution For PDP-11 Based EDS And Image Acquisition Systems
Authors: Mansfield John
Published: March 2018

One of the major difficulties with the older DEC PDP-11 based EDS systems is that they were designed as standalone units. Their manufacturers believed that the systems were capable of performing all the spectral processing that the users would ever need, and therefore did not allow for transfer of data to other computer systems. While some of the vendors have attempted to offer file transfer capabilities as upgrades, typically these upgrades are based on a serial connection using a file transfer program like Kermit. Although such solutions are acceptable for the transfer of small numbers of spectra, they cannot seriously handle hundreds of spectra or digital images data without tying up the EDS computer for extended periods of time. In multi-user environments, it is often desirable to move the data taken in one users microscope session immediately, to avoid filling to capacity the disk space on the acquisition system and rendering the system unusable for the next user.
Reference Methods For Analyzing For Asbestos In Various Media
Authors: Millette James R
Published: March 2018

Microscopy remains the primary tool for the analysis and quantification of asbestos in occupational and environmental studies. The American Society for Testing and Materials (ASTM) has recently approved two new Standard Methods for the analysis of asbestos in settled dust. Both methods require the use of a transmission electron microscope (TEM) equipped with an energy dispersive x-ray analysis system. Other methods curently in use require the use of a polarized light microscope {PLM) or phase contrast microscope (PCM).
Optimization Of Ion Millers For TEM Sample Preparation
Authors:   Past and present members of the Center for Mlcroanalysis of Materials
Published: March 2018

Ion millers are a pain in the neck! They are designed to remove material from the sample. This means: a) that they always remove material from other places too and b) that the material gets deposited somewhere else. The result of this is that ion millers are inevitably high-maintenance instruments.

Therefore it is important to make the most of them when they are in operation. To aid in this quest, two things can be helpful: to get the beam well aligned and to know the milling rate.

An ion gun, however powerful the beam it produces, is of no use if the beam misses the sample. A means of checking the alignment is therefore of great importance.
Variable Pressure Scanning Electron Microscopy For Nonconductive and Volatile Samples
Authors: Hanke Larry D
Published: March 2018

During the past two decades, the scanning electron microscope (SEM) has become an indispensable tool for morphological observation in materials and biological sciences. With energy dispersive x-ray spectroscopy (EDS) and wavelength dispersive spectroscopy (WDS), rapid chemical characterization of microscopic features has also become commonplace. As developments in manufacturing methods allow fabrication of ever smaller devices and quality control has achieved higher priority, demand for microscopic characterization by SEM has continuously increased.

Many applications where SEM/EDS evaluation could be useful involve samples that are not electrically conductive. Nonconductive samples are subject to a buildup of electrons on the examined surface. This buildup of electrons, or “charging” eventually causes scattering of the incoming electron beam, which interferes with imaging and analysis. Nonconductive samples have traditionally required pretreatment, by coating with a conductive film, before SEM examination.
Higher Speed Imaging: Frame Transfer CCD'S
Authors: Sternberg Scott
Published: March 2018

A number of important imaging applications, including neurobiology and precision motion analysis, require a digital camera that provides both high performance (low noise, extended linear gray scale) and high frame rates. In recent years, manufacturers have responded to this need with faster digitization/readout electronics - as high as several MHz (Mpixels/second). When combined with on-chip binning, this has enabled frame rates up to 30 frames/second from some high performance cameras. Unfortunately, even this is not fast enough for situations where two images must be acquired virtually simultaneously, or where a rapid dynamic event needs to be captured with a fast burst of images.
FIB Lift-Out and Milling of Cylindrical Specimens for Electron Tomography (or Atom Probe Field Ion Microscopy)
Authors: Giannuzzi Lucille A
Published: March 2018

Electron tomography using transmission electron microscopy (TEM) and related techniques (e.g., scanning transmission electron microscopy (STEM) or energy filtered TEM (EFTEM)) allow for 3-D microstructural and elemental mapping of specimens, and has been used successfully in the biological sciences where mass-thickness contrast dominates these mostly amorphous materials. Z-contrast STEM imaging via high angle annular dark field (HAADF) tomography has also been used successfully in the physical sciences. STEM, EFTEM, and holography tomography are more useful techniques for crystalline materials, since diffraction contrast in conventional TEM images can hinder image reconstruction. Typical tomography routines utilize conventional electron transparent foils, whereby the dimensions of the specimen perpendicular to the electron beam may be orders of magnitude greater than the specimen thickness parallel to the electron beam. Using this conventional specimen geometry, the effective specimen thickness increases as the specimen is tilted through the ± 70 degrees necessary for the tomographic acquisition process.
A New Improved Silicon Multi-Cathode Detector (SMCD) for Microanalysis and X-Ray Mapping Applications
Authors: Barkan Shaul , Saveliev Valeri D , Iwanczyk Jan S , Feng Liangyuan , Tull Carolyn R , Patt Bradley E , Newbury Dale E , Small John A , Zaluzec Nestor J
Published: March 2018

A silicon multi-cathode detector (SMCD) has been developed for microanalysis and x-ray mapping applications. The SMCD has a large active area (∼0.5 cm2), excellent energy resolution, and high count rate capability. The detector utilizes novel structures that have produced very low dark current, high electric field, uniform charge collection, low noise and high sensitivity to low energy x-rays. The detector's spectral response was evaluated using a 55Fe radioisotope source, as well as by fluorescing materials with an x-ray generator. Figure 1 shows a 55Fe spectrum with an energy resolution of 125 eV FWHM at 5.9 keV collected at 12 μs peaking time. This energy resolution has been repeatably measured on many different detectors. To evaluate the high count rate x-ray performance, which is very important for fast x-ray mapping, a Cu sample was fluoresced using a Rh-anode x-ray tube.
Georgia Microscopical Society Young People's Course in Microscopy January - March 1995
Authors: Millette James R
Published: March 2018

The Georgia Microscopical Society, a non-profit organization mee'jng at the Fernbank Science Center in Atlanta, Georgia, has sponsored a Young People's Course in Microscopy for a second year. This course, open to high school students, met for 8 sessions on Saturday mornings. The course instructors were Society members from educational, governmental and private institutions who donated their time.
What's in Vial No. 3?
Authors: McCrone Walter C
Published: March 2018

Last weekend I taught a special two-day course on the identification of explosives to a young lady from San Salvador. She is a forensic mrcroscopist newly assigned to the "Bomb Squad". Her problem was to determine what explosives were used after terrorist bombings. Fortunately, some small particles of the explosive substance usually remain after a detonating. Careful examination of a bomb crater or of bomb fragments usually uncovers these tiny residues.

My problem was to teach her the microscopical characteristics of the most likely explosives she might encounter. These include common inorganic nitrates, chlorates and percholorates and less common organic (military) explosives such as TNT, RDX, HMX, PETN and tetryl.
The Red Eye Special
Authors: Revel Jean-Paul
Published: March 2018

I am a professor at a university, and like most of my colleagues I divide my time between teaching, administration, service work and basic research. Of all these activities it is the research that I and my students have dene that has been most important for the advancement of our respective careers. Research is indeed the life blood of science and the meeting of MSA in New Orleans this month, will be an occasion to celebrate this and to show each other what we have been doing since we saw each other in Cincinnati last year.

I am driven to write this column because some nights ago I watched a program on the problems surrounding the delivery of the impending “universal” health care package. On the stage were Senators Dole and Mitchell, along with people representing different opinions about the issues at hand.
Methods for Preparing SEM Specimens for Micrography with Black Backgrounds
Authors: Ahlstand Gib
Published: March 2018

The basic trick is to produce a very smooth, featureless background, preferably using low Z (atomic number) or low density materials. The following three methods exploit in 1: round glass coverslips, in 2: double stick tape and/or colloidal graphite paint for backgrounds, and in 3: a combination low Z plus high Z conductive coating strategy is described which when used in combination with 2, also produces the desired background effect.

1. I've done the following for pollen grains, rust spores, and soil particles (dried down onto glass coverslip support surface from water or ethanol, they just stick naturally), should work with larger samples, eg., insects, seeds, provided that any paint you use to mount the sample to the glass coverslip does not spread out beyond the edges of the sample so you don't see it in the background.
High Voltage Scanning Electron Microscopy Theory and Applications
Authors: Rigler Mark , Longo William
Published: March 2018

A variety of energy emissions occur as a result of primary beam interaction with the specimen surface. Secondary electrons, x-rays, visible photons, near IR photons, and Auger electrons are emitted during inelastic scattering of electrons. Backscattered electrons (BSE) are emitted during elastic scattering of primary electrons. Backscattered electrons are those electrons which pass through the electron cloud of an atom and change direction without much energy loss. BSEs may diffuse into the sample or may escape from the sample surface. In practice, the primary electron beam penetrates deeply into low Z (atomic number) materials and produces few BSEs while high Z materials retard primary beam penetration and emit large numbers of BSEs. According to Murata et al., the higher the atomic number, the smaller the mean free path between electron scattering events (i.e. 528 Å for Al vs. 50 Å for Au at 30 KeV) and the higher the probability of scattering.
A Clean SEM System - Why and How
Authors: Bryson Charles E
Published: March 2018

If you were to examine surfaces in a typical SEM system using any number of surface analysis techniques, I think you'd be surprised at the results. You might expect to see all materials used to construct the vacuum chamber (e.g., plastic or stainless steel), but frequently the spectra will show mostly carbon, the most frequent culprit of SEM contamination. Carbon is adsorbed onto the walls of the vacuum chamber and builds up on the sample, thereby contaminating the SEM system and compromising image quality. By manufacturing and maintaining a clean SEM environment, this problem can be avoided, and you will increase the overall performance of your SEM system.
Digital Imaging for TEM Part 1
Authors: Buonaquisit Anthony D
Published: March 2018

We are all familiar with digital imaging for SEM instruments. Digital Imaging for TEM applications is not as well established. Nevertheless, it seems clear that it will not be long before digital imaging for TEM becomes common place. Systems are improving and costs are plummeting. With this in mind it is timely to review what digital imaging for TEM involves.

In normal TEM operation an electron bream is scattered through a thin section of a sample. Physical mechanisms cause the electrons of the beam to scatter, producing bright-field images, dark-field images and diffraction patterns. The operator adjusts the instrument to display one of these images on the instrument's viewing screen. A photographic record is collected by flipping the viewing screen and exposing a sheet of film held in the TEM's camera. Exposed negatives can be removed for developing and printing in batches, using standard darkroom techniques.
Microscopes aren't just for Microscopists, Anymore!
Authors: Carmichael Stephen W
Published: March 2018

Historically, microscopes have been used to gather morphologic data. We have called people who use these instruments microscopists, and it is implied that microscopists are morphologists. As was pointed out in the April/May issue of this newsletter, useful information about a specimen is also gained from temporal analysis. Further, it has been appreciated that the new family of scanning probe microscopes can be used to gather additional types of information so that these instruments have the potential to be useful beyond the dreams of a conventional microscopist. As we will discuss in this article, the future is here for one such application.

The atomic force microscope (AFM) takes advantage of the leverage afforded by the deflection of a laser beam bounced off a cantilevered stylus that is scanned over the surface of a specimen.
Standardizing SEM Beam Current for EDS Without Use of a Current Meter
Authors: Ahlstand Gib
Published: March 2018

If you do not have a Faraday-type incident beam current meter on your SEM, use the following procedure to set up a calibrated, reproducible beam current when doing EDS. Of course, you won't know the actual vaiue of the beam current in picoamps, but at least you'll know you can set the same value from sample to sample and day to day.

Mount a small, clean metal foil, 2x3 mm, aluminum or copper, onto the edge of each stub that the samples and standards are mounted on using colloidal graphite paint or double stick tape (after carbon or other evaporative conductive coatings have been applied to sample). Run a little colloidal graphite around an edge or two to provide additional adhesive support and a conductive bridge between the foil and the stub. Before taking sample or standards spectra, move the electron beam to the foil and as you accumulate its spectrum, set a region of interest, or window, on the principle K-shell peak of the aluminum or copper spectrum.
If You Hate Vacuum Systems Read On
Authors: Buonaquisti Anthony
Published: March 2018

Let's face it, nobody became a microscopist because they wanted to become an expert in Vacuum Science. The fact is that most of us were shown the proverbial “fly's eye” micrograph and fancied ourselves as the Ansel Adams of Electron Microscopy. As a consequence, during the progress of our careers, we have had to come to grips with Vacuum Science, usually on a “need to know” basis. Specifically, when the system has broken down, we need to know who can fix it … when they can fix it … and why they can not fix it sooner…

Nevertheless, the fact is that we ignore vacuum science at our peril. Although microscopes can withstand a lot of abuse before they catastrophically fail, they respond to poor vacuum practice with poor vacuum quality. In the final analysis ifs extremely valuable to have some “Vacuum sawy”.
Posters Platform Presentations Pages & Pages of Publications
Authors: Fisher Robert M
Published: March 2018

1992 was certainly a banner year for microscopy in terms of an incredible total of nearly 3000 presentations given world-wide - at the largest ever joint (E)MSA/MAS/MSC meeting in Boston and at the 3 IFSEM-sanctioned Regional Conferences in Spain, China and Venezuela. Several of the local affiliate societies also mounted well-attended symposia and contributed to the outpouring of words and images. The apparently continuously growing volume of microscopy-related presentations has impacted both conference organizers and publishers.

Poster presentations are being used to an increasing extent to avoid an excessive number of parallel sessions. There is also an economic incentive as a poster session probably costs the organizers less than half that of a platform session of contributed papers. The poster trend draws a mixed response. Most microscopists love to look at posters but hate to prepare them as they are much more work to put together and are costly. They are awkward to carry and often have a one-time use whereas slides are for ever.
Infrared Microspectroscopy And Computer Library Searching
Authors: Smith Kenneth
Published: March 2018

In today's FTIR market, many instrument manufacturers provide software to perform searches of computer library spectra. With the increased speed of computers running FTIR instruments, you can have the result of a computer library search in literally seconds. However, as we rely more and more on computers in the laboratory we need to keep in mind the limitations and possible areas for error in these applications.

Computer library search programs calculate the difference between the sample spectrum and reference spectrum typically based on peak position and intensity. Different searching algorithms can stress one or the other. The result of a computer search is a Hit List with each hit having a hit quotient index (HQI) to indicate how close that particular spectrum matches the sample spectrum. In some programs the quotient which indicates an exact match would be 1 or 100, in others it is 0.
A Simple Method To Make High Resolution Projection Slides of Electron Micrographs
Authors: Ryerse Jan S
Published: March 2018

The traditional method of preparing high quality projection slides of one's best electron micrographs was to “print” negatives onto Kodak 2″ x 2″ emulsified glass slides using a standard enlarger fitted with a reduction lens and then to tray develop the slide to the desired contrast. As A. Kent Christensen pointed out in the June/July 1994 issue of this publication, the cost of 2″ x 2″ slides has become prohibitive. In any event, I always found adjusting the reduction lens on the enlarger to be a major hassle and searching for the correct exposure and developing times to be a ffustratingly inexact experience with much plate wastage.
What did Dickens know about Phaseonium?
Authors: Revel Jean-Paul
Published: March 2018

In the Pickwick Papers, Charles Dickens has his character Sam exclaim that he needed “a pair o’ patent double million magnifyin’ gas microscopes of hextra power” Now the general wisdom is that improvements to microscopy are bounded by the laws of optics which tell us that resolution is a function of the wavelength of the radiation used for imaging and inversely proportional to the refractive index of the medium and lens. We have discussed in this space various ways which can and have been used to “circumvent” mother nature, by such tricks as not using lenses and employing scanning techniques instead in order to obtain images.

It turns out that there may yet be other useful “loopholes” in natural laws. Lefs for example consider the fact that the refractive index of a material is a measure of the interaction of photons with the matter they traverse. In that sense refraction is related to absorption, which occurs when materials interact so strongly with photons that the latter never emerge.
Issues in Cathode Performance: Part 1 - Tip shape and Crystal Orientation
Authors: Christman Locke
Published: March 2018

LaB6 (and CeB6) cathodes are widely used as high-brightness cathodes in a variety of electron beam applications. These cathodes provide about 10 times the brightness and about 100 times the service life of a tungsten filament. However, to fully realize the improved brightness and lifetime of the LaB6 (CeB6) cathode, it must be designed and manufactured specifically for the application.

This article covers tip shape and crystal orientation. Future articles will deal with materials selection, preparation, purity, composition, and cathode operation.

The design of the LaB6 cathode tip is critical for maximum lifetime and optimum performance. The cathode must also provide the appropriate source size, beam current, and beam brightness for the application.

The lifetime of the LaB6 cathode is limited by three basic factors: cathode temperature, vacuum pressure, and tip shape. The first two factors are critical and depend on proper user operation. Poor vacuum and excessive temperatures accelerate LaB6 material loss, which decreases the cathode lifetime. The third factor, tip shape, is also critical, and careful production control ensures that the tip shape is optimized.
The “Glycogen Granule” Revisited
Authors: Rybicka Krystyna
Published: March 2018

There is a gap between biochemical findings and ultrastructural interpretation of “glycogen granules”. Biochemists have recognized that glycogen contains covalently bound proteins. These include enzymes involved in giycogen metabolism: glycogenin (protein primer responsible for initiation of glycogen synthesis), glycogen synthase and phosphorylase, and presumably other regulatory enzymes. The structures formed by the association of glycogen and protein have been called protein-glycogen complexes, considered as proteoglycans, or as dynamic cellular organelles, glycosomes.

The question arises as to why the biochemical recognition of a protein component in glycosomes has not been acknowledged in electron microscopy (EM)? This protein is visible in every section stained by uranium (U) and lead (Pb) salts where it appears as 20-30 nm granules (Fig. 1). However, these granules are commonly interpreted as glycogen, despite the fact that glycogen does not react with ionic compounds and therefore cannot be stained by U-Pb.
Histogram Stretching Or Histogram Equalization In Image Processing
Authors: Oliver William R
Published: March 2018

A few weeks ago, a person posted an interesting question on an internet microscopy mailing list: what is the difference between histogram stretching and histogram equalization when applied to microscopy images? The following is a short intuitive review which compares the two. Since this is a short and general description, I will gloss over some details and make some generalizations which may not be true in all cases and implementations.

The first thing to remember is the basic purpose of contrast enhancement. The idea is simple, In a grayscale (black and white) image you are simply trying to take two levels of gray that are close together, and thus visually similar, and move them apart so you can better see the difference between them. You can think of grayscale values in an image as beads on a string, Contrast enhancement simply moves all or some of those beads farther apart.
Microscopy Reveals Molecular Motion
Authors: Carmichael Stephen W
Published: March 2018

Microscopes are known for demonstrating structure, but there have been many examples of how this is changing. A novel use of the atomic force microscope (AFM) by Manfred Radmacher, Monika Fritz, Helen Hansma, and Paul Hansma at the University of California, Santa Barbara, has extended the versatility of this instrument even further. They demonstrated a conformational change in a molecule that happened in a fraction of a second.

Radmacher et al. pointed out that enzymes perform their biologic function by undergoing a conformational change and that this change is within the spatial and temporal resolving capabilities of the AFM. They set out to prove this by lowering the tip of the AFM onto lysozyme, a molecule that is roughly egg-shaped, measuring about 4.5 nm by 3 nm by 3 nm. Using the tapping mode in liquid, they found that single molecules exhibited a spike-like height fluctation when in the presence of a suitable substrate.
X-Ray Analysis of Materials: Avoiding the Pits and Other Practical Hints
Authors: Sandborg Alan
Published: March 2018

EDS analysis of samples in a SEM or TEM are usually portrayed as a very simple process; just image your specimen, turn on the x-ray analyzer and all will be revealed about the chemistry of your sample. Unfortunately, that approach can be very misleading at best, and disastrous at worst. The analyst should get used to preparing himself for EDS x-ray analysis just like he or she does for any other process. A set of preparation steps should be followed until they become an unconscious method to be used before accepting the information coming from the EOS x-ray spectrum. After proper basic preparation, interpretation of the results and the selection of operating parameters is still very important due to the detailed nature of the specimen.

Preparation: The most basic need is for the EDS system to be calibrated. This can be a difficult or simple task depending on the age of the system.
Soil Technology, A Coming Field and a New Microscopy to Support it
Authors: Newberry Sterling P
Published: March 2018

A quiet report from an international work shop, this fall in London on World Ecology, points out how primitive our knowledge of basic soil science really is. It also records the determination of the participants to bring out the need to study soil in relation to maintaining biodiversity because of man's rapid destruction of global habitat and the inability for soil to recover without it's natural canopy of plant and animal life. It is further pointed out that we have to quickly learn how to reclaim soil, perhaps by artificial means, after insult. The programs they envision will create exciting professional opportunities both for career change and for students over a broad spectrum from basic research to applied engineering. The land fill crises has further underscored the need to find ways to return sewage sludge and other organic waste to useful crop production.
Trapping Subfemtoliter-Sized Vesicles, and Analyzing Them
Authors: Carmichael Stephen W
Published: March 2018

The chemical analysis of secretory vesicles has long been limited by the fact that many vesicles are analyzed together, resulting in an averaging of a population. Differences between vesicles within that population could not be detected. Wouldn't it be great if vesicles could be analyzed one at a time? You guessed it, this breakthrough has been recently achieved.

The technique of capillary electrophoresis (CE) was modified by Daniel Chiu, Sheri Lillard, Richard Scheller, Richard Zare, Sandra Rodriguez-Cruz, Evan Williams, Owe Orwar, Mats Sandberg, and Anders Lundqvist so that vesicles could be probed singly.
Modern Microscopy on the Light Side: TEM in the Trenches
Authors: Rice Stephen E
Published: March 2018

Great strides have been made in the last decade in high resolution transmission electron microscopes (TEMs) which can also provide elemental information via energy dispersive X-ray analysis (EDX) or energy loss spectroscopy (EELS), and proponents of various TEM techniques make bold claims. Convergent beam elecjron diffraction and microdifff action shine as techniques for defect structure analysis and means for solving crystal structures. The spectroscopies can now be used to map chemical state information at a level which until recently might be encountered in science fiction. As a pure imaging device, electron holography holds great promise for providing Ehe ultimate (would you believe 0.1Å?) imaging resolution. Although conventional TEMs will never approach this, it appears that we are learning more and more about less and less, until we will soon know everything there is to know about nothing.
A “Pushy” Microscope
Authors: Carmichael Stephen W
Published: March 2018

The process of ultra-miniaturization has been termed nanofabrication. It looks like the scanning tunneling microscope (STU) and related microscopes will be players in this technology of the future. One of the most recent contributions has been the demonstration that single molecules can be “pushed” across a surface with the STM. This remarkable achievement was demonstrated by Thomas Jung, Reto Schlittler, and James Gimzewski of the IBM Zurich Research Laboratory and Hao Tang and Christian Joachim of the National Center for Scientific Research in Toulouse, They were able to position intact individual molecules on a two-dimensional surface at room temperature by a controlled “pushing” action of the tip of a STM. Similar positioning feats have been done at low temperatures while thermal motion is limited.
Top Light With The Polarizing Microscope
Authors: McCrone Walter C
Published: March 2018

To adequately microscopically characterize opaque particles, and some finely divided, high refractive index, and transparent particles, one must use top light. This can be done with a built-in or accessory vertical illuminator. It can also be done without a vertical illuminator using any PLM with any separate microscope illuminator focusable to a small bright spot. Aimed downward onto the slide preparation at a steep angle, but missing the objective, and with the transillumination subdued or turned off, the color and surface texture of opaque particles can be readily discerned. The objective must have a long working distance, usually, therefore, a 10X or lower magnification.

Pseudo opaque particles (submicrometer particles of high index) are reaify transparent but hey may be colorless or any color. Top light brings out their true color - black, if opaque, but they may be red (Fe2O3), green (CR2O3), yellow (lead-tin yellow) or white (TiO2).
Digital Imaging For TEM
Authors: Buonaquisti Anthony D
Published: March 2018

Part 1 of this series, in the August '94 issue of this newsletter, contained an overview of digital imaging for TEM. The key point was that digital imaging systems are getting better and costing less. This article contains a brief summary of the pro's and con's of digital imaging for TEM.

Although different laboratories have different situations, there are common issues that all can consider when evaluating the value of a digital imaging system for TEM.

Information Density: As things stand today, atypical 1024 pixel by 1024 pixel digital imaging system cannot compare with film! Typical film used for EM can display feature sizes as small as 10 μm. This is like having a film negative made up of 10,400 pixels by 7,800 pixels. Put this way it's tough to see how a factor of between 7 and 10 can be ignored.
A Microscope that looks Sideways
Authors: Carmichael Stephen W
Published: March 2018

When most of us use a microscope, we are looking through a specimen, or more and more frequently, at the “top” surface. It usually doesn't occur to us to look sideways. But that is what was done recently in the laboratory of Charles Lieber at Harvard University. As reported by Daniel Frisbie, Lawrence Rozsnyai, Aleksandr Nay, Mark Wrighton, and Prof, Lieber, an atomic force microscope (AFM) was modified to perform as a “chemical force microscope” (CFM). With the CFM they were able to precisely measure adhesive and frictional forces. These forces can be thought of as acting parallel to the surface of the specimen, whereas most observations are made perpendicular to the surface.
A Hitchhiker's Guide to Microscopy & Microanalysis Using Telecommunications, Email and the Internet
Authors: Zaluzec Nestor J
Published: March 2018

The Information Superhighway, Email, The Internet, FTP, BBS, Modems,: all buzz words which are becoming more and more routine in our daily life. Confusing terminology? Hopefully it won't be in a few minutes. All you need is to have a handle on a few basic concepts and terms and you will be on-line with the rest of the “telecommunication experts”. These terms all refer to some type or aspect of tools associated with a range of computer-based communication software and hardware. They are, in fact, far less complex than the instruments we use on a day to day basis as microscopists and microanalysts. The key is for each of us to know what each is and how to make use of the wealth of information which they can make available to us for the asking.
Processing Cochlea For Paraffin Sectioning And SEM
Authors: Montague Donna C
Published: March 2018

We have successfully sectioned decalcified paraffin embedded “inner ears” from mice, rats and humans. We have also prepared guinea pig cochlea for SEM, So, briefly:

Paraffin:

1) Immediately after dissection, place the cochlea in 10% neutral buffered formalin (NSF) and let fix with gentle agitation 24 hours per 2 mm thickness at room temperature. 2) Decalcify by immersing in 5% formic acid at least 4X specimen volume. 3) Gently agitate at room temperature and change at least once per 24 hours. Check for completeness of decalcification by decanting 4 mLs of “spent” formic acid into a clean, clear test tube, Add 1 mL of 5% ammonium oxaiate in distilled water. Let stand undisturbed for 15 to 20 minutes, White precipitate of calcium oxaiate indicates that the sample is not completely decalcified, Change formic acid at least once per 24 hours until the spent formic tests clear.