Fluorescence microscopy has revolutionized cell biology. Not only has it increased the spatial resolution with which certain processes are visualized, but it has allowed microscopists to monitor more than one event at a time. One of the remaining challenges is to see how proteins fold and assume their native conformations within living cells. Recently, Nathan Luedtke, Rachel Dexter, Daniel Fried, and Alanna Schepartz have demonstrated a technique to demonstrate these events in situ.

The discovery of viable microbial life in ancient glacial ice has opened up a plethora of questions related to how life can be sustained in such extreme environments. Cryo-microscopic analysis of lab prepared ice samples indicates that microbes are located in the small veins of water that exist between individual ice crystals. Crucial to these studies is to obtain an understanding of the physicochemical habitat for life through physiological and microscopic analysis.

Between the Biological and Materials sciences resides the food industry, where both biological and materials methods and techniques are employed for both production and analysis. Often referred to as “Black Specs,” one of the biggest concerns for the food industry is contamination of the food, or its additives and ingredients, with foreign material (FM). Many of our customers seek assistance in solving their FM issues, which may require multiple instrumentation, several methods, and considerable open communication with the customer before a satisfactory result can be achieved. An additional level of difficulty is often present when we learn that the FM is so small we can barely detect it with the unaided eye. Particularly difficult is what might be referred to as “chemical contamination.” We present here in example (and in the upcoming Microscopy and Microanalysis meeting in Albuquerque this August), several of the methods employed in assisting our customers with FM issues.

We have all heard the quote “A picture is worth a thousand words” when describing how much information can really be represented by a single image. Many of you may have written and published pages of results all based sometimes on a single piece of important data such as an electron micrograph. Of course, if one image is worth a thousand words, as the saying goes, how much would 30 or more be worth? With the advent of better performing electronics and development of newer CCD (charge couple device) technology, it is now possible to extend the famous saying and complete it with “but a movie tells the whole story”. By extending the single acquired image into a series of fast-acquired frames, movie creation is possible. This capability allows us to record dynamic events in many different applications, leading towards sharing the sequence of images and telling a more complete story that cannot be done with one image alone. A brief background on how this technique is used in electron microscopy follows.

Most spectroscopies (FTIR, XRD, RAMAN, MS, etc.), were developed in order to identify materials. This is accomplished by capturing the spectral “signature” of an unknown and matching it to those of a comprehensive database of reference materials. Development of these spectroscopies has included efforts to embellish the associated database. EDS evolved as a resource to provide qual/quant, and development has been to improve the accuracy of quantation. Until recently, EDS was not considered a spectroscopy to provide identification of materials.

Modern semi-crystalline polymers based on olefin chemistry are receiving a lot of attention due to their low cost of manufacture and the ability to tailor properties by controlling polymer morphology. A common technique to visualize polymer morphology is transmission electron microscopy (TEM), with the use of appropriate contrast-enhancing heavy metal stains. One of the difficulties in obtaining a TEM image is the need to prepare an ultra-thin section. Alternative approaches that do not rely on sectioning, such as AFM and SEM imaging of a prepared block face, have shown some promise for gross morphology characterization (μm-scale) but in most cases lacked the detail that can be observed by TEM.

Metallographic examinations of uranium, as carried out with both optical and orientation contrast microscopies (electron backscatter diffraction or EBSD), typically require a final preparation step that involves acid-etching or electropolishing. Uranium oxidizes relatively rapidly after mechanical polishing, making EBSD impossible without additional preparation steps. Conventional specimen preparation generates a mixture of acids and radioactive waste, so-called “mixed waste” as defined by the Resource Conservation and Recovery Act (RCRA). Mixed waste is more costly to dispose of than either separate component and there is a desire to eliminate mixed waste streams. One simple method to avoid the use of acids in optical metallography is to wait a few minutes for the sample to differentially oxidize to obtain the desired contrast. However, this method is disadvantageous when more than a few micrographs are needed because the sample continues to change with each micrograph.

Food ingredients are often made by extruding flours and starches derived from cereal grains with proteins. Extrusion is carried out at high temperature, high shear and low water conditions to make low density, foamed pellets that are used as food ingredients. The structure of the crisp matrix varies greatly with the ingredient proportion and is important in forming the organoleptic properties of the crisps. However, it is very difficult to analyse the structure of the matrix with respect to the distribution of the major components, and the authors have been unable to find references for these materials. Furthermore, the materials must be stained without wetting as water will destroy the integrity of the crisps.

One of the main obstacles to performing electron crystallography analysis in a TEM is that the acquired electron diffraction data often exhibits some form of distortion introduced by the lens system. Recognizing this problem, Capitani et al. has proposed a method to detect such distortion, which is primarily elliptical, by using a single crystal standard. Once such elliptical distortion is characterized, electron diffraction data acquired later can then be corrected by means of image processing. However, it may be desirable to correct such distortion at the instrument level. In this article, a different approach to measuring diffraction elliptical distortion is proposed by characterizing diffraction ring patterns and it is demonstrated that by varying the objective lens stigmation settings, it is possible to eliminate this elliptical distortion completely.

The covering wings (elytra) in the Colorado potato beetle Leptinotarsa decemlineata appear shiny, smooth, water-repellent, and slightly slippery, (Fig. 1). These properties are due to the presence of epicuticle, the outermost layer of the insect integument, covered by a wax-like lipid surface layer called grease. Surface waxes have been previously reported in a variety of conditions, from liquid viscous coatings to crystalline structures in form of plates, rods and filaments from many insects (adults and larvae) and arachnids (Hadley, 1981a,b). Beament (1945) and Wigglesworth (1945) considered an outer thin layer of solid wax, whereas Lewis (1962) rather assumed an oil film on the epicuticle surface to be widespread throughout insects.

In recent years the development of remote microscopy, specifically in electron microscopes, has begun to emerge as a useful research tool rather than simply an educational or teaching aid. Scientists have long been able to work collaboratively at a distance; however, it is often in terms of receiving data or sending some instructions where there may be a delay in receipt of the information. When defining remote control it is important to note that electron microscopy requires instantaneous control and receipt of the feedback (in most cases via images on a screen). Without realtime control it is impossible to conduct high resolution imaging and analysis work. In terms of electron microscopy, there are several reasons for conducting experiments remotely: With sub-Ångström aberration-corrected scanning transmission electron microscopes, the environment within which the microscope itself sits is of utmost importance.

Electron backscattering diffraction (EBSD) has become a technique of great importance in scanning electron microscopy. The diffraction patterns obtained by this method are of value in identifying phases and in determining the orientation of samples. The technique was initially developed about thirty years ago and has enjoyed widespread use in the last decade or so. It is therefore something of a surprise that there do not exist computer programs that simulate the patterns well. In fairness, we must make it clear that a number of programs exist and others are being implemented, which represent important steps towards the simulation of EBSD patterns. However, as we hope these notes will make clear, a satisfactory simulation will be very difficult and we are not aware of any existing or forthcoming program that does a job that can be guaranteed to give accurate values for the intensities in the experimental patterns.

A purpose of microscopy is to magnify and enhance contrast between different regions of a sample, whether those regions may be different structures, different orientations of the same structure, regions of different atomic weight, or different chemistries. In the present case, elemental mapping in the energy filtered transmission electron microscope (EFTEM) is used to enhance contrast between elements in an apparent bundle of fibers previously seen through scanning electron microscopy (SEM) and a particle that appears to be a catalytic source for the fibers.