Teaching on-site courses for the McCrone Research Institute has enabled me to see a lot of the USA. The van and I have been to all of the states except Hawaii and Alaska besides all of the Canadian provinces except Newfoundland and the Northwest Territories. Some parts of the USA have become nearly as familiar to me (and van) as the Outer Drive in Chicago, Rte. 1 down the California coast, Rtes. 80 and 90 to New York and New England, 55 and 65 South, 40 Southeast to Los Angeles and 80 to Salt Lake City and San Francisco, in particular. The latter route across the Great Salt Lake Desert is one of my favorites. That route is always different because of the Great Salt Lake. It's a large lake under normal conditions but conditions are never normal.

What happens when a cup of water and two ice cubes, contained in a bowl, are placed side by side in an 800 watt microwave oven and microwaved for two minutes at 100% power? The answer may not be obvious, even to the most ardent microwave user. The water will boil and the ice will remain essentially unmelted. This dichotomy of the results may appear puzzling to the casual observer, or may explain why your food does not defrost quite evenly. To the microwave, however, it all makes sense. Water is a dielectric and absorbs microwave energy. The net result is that it heats up. The ice under the above conditions is essentially transparent to the microwave and does not heat. It would take an ice wall greater than 30 meters thick (3.4 cm for 25° C water) to protect you from the microwave energy emitted by the standard household microwave, whereas a >170 nm thick piece of aluminum foil is all that is required to reflect that same energy.

Lateral Force Microscopy (LFU) is a scanning probe microscopy (SPM) technique that identifies and maps relative differences in surface frictional characteristics. It is one of several techniques developed as extensions to the basic topographical mapping capabilities of SPM. LFM is particularly useful for differentiating among materials on surfaces. Applications include identifying transitions between different components in polymer blends, composites and other mixtures, identifying organic and other contaminants on surfaces, delineating coverage by coatings and other surface layers, and chemical force microscopy using functionalized tips.

The present-day interactive manual selection of biological molecules from digitized micrographs for single particle averaging and reconstruction requires substantial effort and time. Thus a computer algorithm capable of recognition of structural content and selection of particles would be desirable. A few approaches have been proposed in the past. The method by Frank and Wagenknecht is based on the principle of correlation search. Van Heel's method is based on the computation of the local variance over a small area around each point of the image field. The method by Harauz and Fong- Lochovsky is based on edge-detection.

This month we are going to deviate from Mark Lund's normal discussion and talk about one of the practical problems that must be considered when using an x-ray detector on a scanning electron microscope to solve real-world problems.

Several years ago I worked in the analytical laboratory of a major semiconductor manufacturer. One day a process engineer came into the lab and asked us to develop an analytical method to determine the amount of copper in an aluminum film on a silicon wafer. The levels of copper would be somewhere between 0.5% and 1.0%. He gave me a sample, saying that he didn't know the exact concentration of copper but was certain that it was at least 0.5%.

With the complexity of polycrystalline materials, a number of techniques have evolved to assist in the resolution of the crystallography of these materials. Conventional methods provide partial information regarding grain size, and can produce estimated orientation distributions. However, these techniques have not been able to provide the spatial placement of lattice orientations, which is necessary for a complete picture of the microstructure of a materials sample. Furthermore, many materials characteristics, such as fracture and corrosion, are determined by site-specific, rather than average, crystal lographic features.

I manage a university service electron microscope facility which provides transmission, scanning transmission, and scanning electron microscopy, each with X-ray energy spectrometry, as well as feature analysis, specimen preparation, and training services. Clients of the facility do basic and applied research in:

• human, animal, and plant health, pharmacy, and bioengineering;

• air, water, and soil ecology, pollution, and resource development and conservation;

• forest pathology, productivity, and development and performance of wood products;

• foods and nutrition:

• engineering, advanced metallic, ceramic, glass, and polymeric materials development, failure analysis, and tribology:

• botany, entomology, microbiology, zoology, chemistry, geology, and physics.

A good scanning electron microscope is not measured only by its ultimate resolution but often by its flexibility as well. In the real world not many samples require their surface to be examined at 100,000X to 300,000X. Other real considerations are its analytical capabilities, such as EDS and WDS for chemical analyses and its flexibility to handle odd samples or odd applications, such as STEM imaging, electron channeling, cathodoluminescence, etc.

Have you ever wished that the lowest magnification of your SEM wasn't 10X or 20X, but rather 5X or 2X or 1X or even lower? This can be especially useful in a forensic application where large samples are common and cutting them or using other destructive techniques would render the sample useless in court.

We report here on the first year of development of a novel teaching facility which incorporates new techniques designed to reach new audiences without diluting subject content. Interactive computer software coupled with rich scientific content of microscopic images provides a unique opportunity to help students learn science and technology, the laboratory is comprised of twenty student workstations networked to various microscopes, thus expanding the number of students capable of "hands-on" data acquisition and analysis by twenty times. Two scanning electron microscopes (SEM), a transmission electron microscope (TEM), and several light microscopes (LM) are interfaced through a server to the workstations.

For over 5 years, here in Pathology at Tuiane, I have used color thresholding (CT) rather than monochrome thresholding (MT) for objective quantitation of histological, immunohistological, fluorescent and thick TEM sections. Technical aspects distinguishing CT from MT were recently described in detail, and this technical note represents an abbreviation of the last paper, which I recommend for those beginning to use video imaging technology. The system I use is the V150 (r) from ONCOR. Despite the advantages of today computers, data outcome, e.g., unbiased, still depends on good experimental design, strict control and repeatability. When the stain of interest is histochemically derived, my laboratory follows standard procedures found in the Handbook of Histopathological and Histochemical Techniques. When the stain is immunohistochemically derived, my laboratory checks cross reactivity of every antibody with known positive and negative control tissues besides using irrelevant antibodies or omitting the primary antibody. In addition, preabsorbing the antibody is done whenever its substrate is available.

In this series we have explained why x-ray spectrometers are useful in electron microscopes and, to some extent, how they work. In this article I will discuss some of the physics behind the detector.

First I have been asked to explain what a hole is. In a silicon crystal every silicon atom is bound to four others with covalent bonds. Every electron has a home, which consists of its home atom in the case of the inner electrons. The four outer (or valence) electrons have a home on the road, shuttling back and forth between too atoms each. In this way the five atoms share eight electrons among themselves.

Over the years a number of methods have been described to mount tissue sections on glass slides (for example see Humason 1979). This paper presents a novel mounting medium that is inexpensive and readily available at the nearest grocery store - floor polish. This floor polish is available under a variety of trade names (e.g., Brite® and Future® both from S.C. Johnson and Son. Racine, WI) labeled for use with "no-wax" floors. It has been found that this product is well suited to use as a mounting medium for both gelatin/albumin embedded sections as well as epoxy sections. The floor polish has demonstrated a much lesser degree of tissue distortion in some tissues as compared to the mounting media previously used in our laboratory, including Permount® (Fisher Chemical, Fair Lawn, NJ) and 30% sucrose in distilled H2O.

The following image is of a LaB6 crystal formation created at the FEI Company, Hillsboro, Oregon. The photograph was taken through a Bausch & Lomb Stereo Zoom 4 at 30X with a Polaroid MicraCam.

The single crystal LaB6 and CeB6 is grown and fabricated at FEI using a well-defined process known as "Inert Gas Arc Float Zone Refining." This process takes place in an inert gas atmosphere and utilizes an electrical arc to melt the hot, pressed powder sample of LaB6 or CeB6. This not only allows the growth of the crystal, but also hefps to purify the material. Through research and 20 years of experience in the growth of rare-earth boride single crystals, FEI can carefully control the material composition (e.g. stoichiometry of B/La) tor the highest possible ratio of electron emission to evaporation rate.

Total replacement of a diseased or traumatized hip joint is fast becoming one of the most common surgical procedures. The acetabular prosthetic shell is gaining widespread acceptance as a socket replacement for this procedure. Bio-materials research is providing a wealth of information regarding the life span, wear characteristics, and performance of these replacements, with a major clinical finding being the destruction of bone (osteolysis) at interfaces with the implants. Osteolysis is widely thought to be associated with the particulate wear debris released from articulation of the ball and socket. Formation and release of these particulates will depend not only on the relative motion occurring but also on the surface roughness of the replacement materials.

With the new "L" brackets that are available for the Tripod Polisher™ (South Bay Technology, Inc.) which allow the sample to be easily backlit with room lights, it is relatively easy to grind away most of the material to be removed when polishing the second side of a sample. The following steps outline the procedure that I have been using for rapidly removing material and getting the samples very thin prior to starting the final wedge polishing. The samples that I have been preparing with this technique are approximately 1µm thick, pulsed laser deposited ZnO-WS2 films on SiC substrates.

Frequently, the need arises for the measurement of the beam current in an electron microscope. For good quantitative analysis with either energy dispersive or wavelength dispersive spectrometers, the beam current is essential. The value of the beam current is used in quantitative microanalysis programs to equilibrate the production of X-ray generation between an unknown sample and a known calibration sample, i.e., a standard. Measurement of the beam current over time can also be quite helpful in determining problems with instrument stability. The following is a description of two very inexpensive methods for making a Faraday cup for measuring beam current in an SEM. It assumes that the microscope has a specimen current meter.

The use of infrared microspectroscopy for examining polymer systems has been well known for some time. Fibers, inclusions in polymers and multilayered films have been examined by this technique. One limitation of the technique is the difficulty of sample preparation. A variety of methods have been proposed to prepare the sample including excising an inclusion, microtoming and the use of diamond cells to squeeze the sample into an appropriate thickness. Spectra-Tech purveys a diamond Micro Plane to prepare thin sections of polymers as well as an ATR objective to avoid the necessity of preparing thin sections. Ing Shaw et al. have proposed the use of a fiber microtome to prepare samples and claims that this technique is faster and easier than conventional microtoming.