One of the capabilities of electron microscopes is to obtain diffraction patterns, which can be analyzed to give information about the structure of the specimen. This brief review discusses some of the technical considerations in using electron diffraction patterns for structural analysis. The technique of selected-area electron diffraction uses diffraction obtained from a limited region of the specimen.

Designing a microscopy and/or analytical instrumentation facility can be completed in a step by step approach, whether it is a completely new facility or an existing one moving into expanded quarters. The procedure is independent of size. The same basic procedure is required for one room or an entire building. There are several major factors that must be taken into consideration. Check lists can be compiled by the microscopist/analyst. One should easily be able to start at any point along the way. The time and effort Initially put into the design will pay for itself many times over in both the convenience and efficiency of the resulting laboratory.

In addition to other determining factors, the optical quality of images is strongly dependent on the quality of the lenses and the spectral characteristics of the incident light in light microscopy as well as in astronomy. Chromatic aberration is one of the most important reasons for limitations of the hotgraphic quality. Ideal lenses that are completely free from such aberrations do not exist. A little chromatic aberration remains in “high-end” apochromatic lenses. Moreover, several lenses for special applications, e.g. microscopic objectives for long focal distances and thick glass plates or objectives with an integrated iris diaphragm for observations in dark field, are mostly not apochromatically corrected because of their optical compromises.

In order to meet the challenges of more economical and environmentally benign energy production, a new generation of complex materials and devices are being developed, including thin film solar cells, fuel cells, and batteries. In all stages of development there is a requirement for materials characterization and analysis, from the initial development stages through to testing of the finished product. Most materials need to be analyzed for compositional homogeneity across surfaces and also for confirmation of film thickness and layer chemistry.

It is a common practice to use microscopic images to describe the differences observed between plant tissues. The images illustrate the taxonomic characteristics of the studied species. In this work we introduce a quantitative method for conducting these analyses utilizing digitized images obtained via scanning electron microscopy (SEM) of barley leaf surfaces. The topography of the leaf surfaces of a narrow-leaf mutant and its wild type mother line was characterized, see figure 1, using the Rotated Image with Maximum Average Power Spectrum (RIMAPS) technique and the Variogram method. Spectra resulting from RIMAPS analysis allow us to identify the specimens and to distinguish between the adaxial or the abaxial side of the leaf. These results are complemented by obtaining the typical scale lengths that characterize the abaxial surfaces of both the mutant and the mother line barley leaves.

The Focused Ion Beam (FIB) instrument, originally designed for semiconductor circuit modification and repair, has found considerable utility as a tool for specimen preparation in several microscopy disciplines and for micromachining small parts. Essentially, a FIB makes very small and precise cuts into a target sample, which implies well-controlled etch rates and close tolerances of surface finish. However, redeposition can affect etch rate and final surface topographies. This work quantifies this redeposition as it modifies yields for different parameters of etching; models the influence of redeposition as applicable to all ion beam processing; and optimizes FIB processing parameters for enhanced yields.

Low-energy ion scattering (LEIS) has gained new capabilities and now provides high-end instrumentation for real-world surface analytical applications. Although the technique has been available for some decades, recent developments in instrumentation make the unique capabilities of LEIS accessible for everyday applications. Special ion energy analyzer designs allow LEIS to be used for non-destructive quantitative analysis of the elemental composition of the outermost atomic layer with high sensitivity and high mass resolution. At the same time, the composition of the first 10 nm of sub-surface material is also assessed. Applications are very broad, ranging from catalysts to various thin films to polymers.

The use of photoactive compounds in microscopy has a long history. Caged compounds have been used for almost forty years, not only to elicit chemical reactions in cells, but also to mark specific cells or regions within cells by photoactivation of fluorescence. During the last seven years, the advent of photoactivatable GFP (PA-GFP) and its successors has opened up a myriad of new applications. All of this work has, of course, been greatly facilitated in live cells through the possibility of genetic labeling that is given by the fluorescent proteins. However, even as more photo-activatable and photo-switchable proteins are discovered, they are still limited in terms of wavelength ranges and photophysical properties. Thus, there has been a resurgence of interest in small organic photoactive molecules for cell biology experiments. In this short introductory overview, we will present the basic concepts of photoactivation and discuss many of the strengths and limitations of various approaches. We will also provide a general description of the kinds of applications for which these probes can be used.

“Second best no more” was the title of an article written by David C. Joy for Nature Materials. The article was for highlighting a breakthrough made by a team formed between Brookhaven National Laboratory (BNL, USA) and Hitachi High Technologies Corporation (HHT, Japan). Sub-angstrom secondary electron (SE) images were obtained on a Hitachi HD-2700, which is a combined scanning electron microscope (SEM) and scanning transmission electron microscope (STEM) operating at a maximum accelerating voltage of 200 kV. For the first time, single atoms and atomic lattices on crystal surfaces are unambiguously presented in SE images.

The ambition to produce a functional miniature microscope suitable for tropical disease diagnostics in developing countries has exercised the ingenuity of many talented designers over the last 75 years. In the early 1930's the late Dr John McArthur produced the first prototype of his pioneering folded optic design and this portable gem measured a mere 102 x 63 x 51 mm, yet was able to deliver everything which would be expected from a conventional bench microscope of similar optical specification (see Fig. 1A).

To achieve this high degree of miniaturization McArthur employed a folded optical prismatic system: light entered from above the microscope via a mirror and then passed through a small condenser to the specimen, a revolutionary concept at that time. The objectives were arranged below the specimen and the image was reflected by two prisms to the eyepiece.

The confocal laser-scanning microscope (CLSM) has enormous potential in many biological fields. When tests are made to evaluate the performance of a CLSM, the usual subjective assessment is accomplished by using a histological test slide to create a “pretty picture.” Without the use of functional tests many of the machines may be working at sub-optimal performance levels, delivering sub optimum performance, and possibly misleading data. In order to replace the subjectivity in evaluating a confocal microscope, tests were derived or perfected that measure field illumination, lens clarity, laser power, laser stability, dkhroic functionality, spectral registration, axial resolution, scanning stability, PMT quality, overall machine stability, and system noise (1-3). It is anticipated by using this type of test data, performance standards for confocal microscopes will be obtained and the current subjectivity in evaluating CLSM performance will be eliminated.

Transmission electron microscopy (TEM) continues to play an important role in diagnostic surgical pathology, particularly in such areas as kidney pathology and tumor diagnosis, among others. Diagnostic TEM is subject to unique time constraints, quality control regulations, and other problems not seen in other TEM applications. The diagnostic TEM laboratory must produce high-quality electron microscopy on small samples which frequently are suboptirnal in fixation and tissue quality due to the pathology involved and time factors associated with biopsy and surgery.