Green fluorescent protein (GFP) and related molecules have been important signal molecules for cell biologists because they emit a bright signal to mark the position of tagged structures as well as changes in calcium and proton concentrations. Related molecules even emit in different colors. Now Hendrik Dietz and Matthias Rief from the Technical University of Munich have given us a detailed look at the "energy landscape" of GFP with the promise that it may also be useful indicator for forces.2 In this context, energy landscape refers to a three-dimensional map of the energy levels of the molecule as it is transitioned from its native state to an unfolded state.

The Space Shuttle Columbia was returning from a 16-day research mission, STS-107, with nominal system performance prior to the beginning of the entry interface into earth's upper atmosphere. Approximately one minute and twenty four seconds into the peak heating region of the entry interface, an off-nominal temperature rise was observed in the left main landing gear brake line. Nearly seven minutes later, all contact was lost with Columbia. Debris was observed periodically exiting the Shuttle's flight path throughout the reentry profile over California, Nevada, and New Mexico, until its final breakup over Texas. During the subsequent investigation, electron microscopy techniques were crucial in revealing the location of the fatal damage that resulted in the loss of Columbia and her crew.

Fluorescent fusion proteins are widely used to visualize the localization of proteins in worms, fish, flies and tissue culture cells. We have used two different methods that use high pressure freezing (HPF) combined with correlative light microscopy (LM) and TEM. The first method uses fluorescence from live organisms immobilized in agarose followed by HPF and standard freeze substitution in dry solvent with osmium. This pre-embedding method optimizes ultrastructural preservation. A second, post-embedding method preserves fluorescence and immunoreactivity from embedded and polymerized thin sections. Here we describe post-embedding fluorescent integrated TEM images (F-TEM).

Fluctuation microscopy is the enigmatic name given to an otherwise straightforward technique for studying medium range order in highly disordered materials. By medium range, we mean atomic ordering at length scales within the range 0.5-2.0 nm, where traditional imaging and diffraction techniques have the most difficulty detecting structural correlations in amorphous materials. Puzzlement over fluctuation microscopy generally arises not because of the "microscopy" part of the name, but because of the "fluctuation" part. What, exactly, is fluctuating? And, why does it fluctuate?

The fluctuations are simply the variations in scattering between small sub-volumes within a thin sample. These are usually not timevarying fluctuations (although they could be), but instead they are the position-varying fluctuations in local diffraction.

Viral infections can be focal and therefore difficult to find by electron microscopy. In addition to sampling limitations, sometimes the only specimen available for examination is tissue that has already been prepared for light microscopy (LM). We have diagnosed a papovavirus infection in skin by embedding hematoxylin and eosin (H&E)-stained sections for ultrathin sectioning and transmission electron microscopy (TEM).

Immunosuppressed patients can have unusual infections or infections in unusual locations. These agents may be difficult to identify due to their not being suspected and incorrect tests being ordered.

When electrons pass through a material, they can pass through without losing energy such as elastically scattered electrons or they can lose or gain energy by inelastically scattering with the material's electrons. The elastically scattered electrons have been used in the simulations of lattice images, which are used to help determine the atomic structure of materials. Inelastically scattered electrons were ignored in the simulations because it was believed that they did not have the required coherence to interfere with themselves and they contributed only to the background intensity. Recently though, a great deal of interest has been generated in knowing whether the inelastically scattered electrons can also contribute to the lattice images in order to help explain the Stobbs factor [1], where the contrast in the lattice images is often three or more times less than the theory predicts. The Stobbs factor makes it difficult, if not impossible, to establish quantitative values to high-resolution lattice images.

The majority of human pathogens cause disease in a biofilm lifestyle. Biofilms are communities of cells that remain attached to a foreign surface and to each other. The organisms secrete and become embedded in an extracellular polysaccharide matrix. Biofilm infections occur most commonly on implanted medical devices and are quite recalcitrant to antimicrobial therapy. The most common device involved in these infections is the intravenous catheter. More than 5 million intravenous catheters are inserted into patients in the United States annually of which up to 10% become infected with biofilm producing pathogens.

The stereo microscope is the most commonly used microscope. This applies to both the materials science and biological science fields. My past career as a materials engineer depended critically upon the three dimensional imaging of the stereo microscope for studying metal parts and fracture surfaces. Unfortunately our clients had no readily available way to view stereo pairs, so stereo pair recording was not done. Likewise, our electron microscopes were not equipped with costly eucentric stages, which make stereo pair recording easily done.

Presently, there is an increasing demand for multi-view TEM observation of semiconductor device failure locations where the feature size of interest is smaller than the specimen thickness, and where the thin section has other features that may have high Z materials that obscure the site of interest in the TEM. Therefore, different viewing angles are necessary — such as a cross-section view of a defect-containing planar thin specimen. A major obstacle for the preparation of three dimensional specimens of this nature is specimen preparation. Great care must be taken when preparing a thin specimen from an already thin existing TEM specimen.

ASTM International publishes many standards specifically about microscopes and using microscopy. The value of these standards falls into three distinct categories. First, they can be a quick tutorial on how to perform some operation. E 1508, "Standard Guide to Quantitative Analysis by EDS" is only eight pages long and falls into this category. Second, they can be used to standardize a test and reporting method. The methods described in E 1382, "Standard Test Methods for Determining Grain Size by Semiautomatic and Automatic Image Analysis" are examples of procedures that have been agreed upon for many years.

Costa Rica is amazing. You probably know that Costa Rica has no armed forces and that fully a quarter of its area is given over to national parks and other protected areas. You probably don't know that Costa Rica is also amazing for its electron microscopy. Almost anonymously Costa Rica has a center for electron microscopy on a par with centers in the United States or Europe.

El Centro de Investigation en Estructuras Microscopicas, CIEMIC (The Center for Microstructural Research) has its own purpose-built building with an infrastructure that would make most of us envious.

For people in a small EM lab, keeping stable stain solutions that don't accumulate precipitates over time can be a problem. Over the last 26 years, I have adapted the method originally described by Venable and Coggeshall (1) to address this need