Many animals can walk up vertical surfaces or even along the ceiling. And many studies have examined how flies accomplish this impressive task. Whereas these studies have revealed the anatomy of the contact area and there have been many assumptions about the fly attachment mechanism, the main elements that contribute to the attachment force were unknown. However, Mattias Langer, J. Peter Ruppersberg, and Stanislav Gorb have successfully demonstrated that the fluid secreted from the fly's feet is a critical factor in attaching the fly to the ceiling.

Many believe that microfluidics has the potential to do for chemistry and biology what the integrated circuit has done for electronics — integrating tremendously complex chemical and biological processes into simple easy-to-use devices that will eventually pervade our lives. While microfluidics has made great progress in the last decade — addressing many of the fundamental questions related to manipulating nanoliter volumes of chemicals and solutions — it still faces some very basic challenges as it moves out of the laboratory and into use. Perhaps most basic is the need for fast, accurate characterization of the size and shape of the microfluidic devices themselves. Conventional imaging and measurement techniques have proven adequate for initial development, but are unable to provide the speed and accuracy needed to support the continued development of microfluidic technologies.

E.H. Andrews [1] was the first to produce transmission electron micrographs that differentiated between crystalline and amorphous forms in long chain polymers. Working with thin cast films of cis-polyisoprene {natural rubber (NR)}; he examined them in the unstrained and strained states. Staining the unstrained thin films with osmium tetroxide vapors, he showed that spherulitic crystals were in light contrast whereas the darker contrasted matrix was the amorphous continuum (Figure 1).

Low voltage field emission SEM (i.e., operated at several hundred volts to 5 kV), offering advantages in surface imaging due to reduced beam penetration,1 was found to be particularly useful in the investigation of uncoated, fine, geological materials down to the nano-scale. Here are four examples to highlight projects being conducted in our FESEM facility.

Kaolinite is one of the most important industrial minerals. Information about its surface properties and cation exchange capacity are important in both ore processing and applications of the clay mineral.2 Low voltage (LV) secondary electron (SE) imaging (Fig. la) reveals detailed (001) surface features of kaolinite, which are not obtainable with high voltage SEM (Fig. lb) and TEM. Kaolinite is highly sensitive to beam damage and can show obvious degradation after just a few seconds under the TEM beam. However, microtomed TEM samples maybe easily examined under LV SEM to show their thickness perpendicular to (001) and cross section features. Such information allows easy access to direct surface area determination of clay minerals.

The ultimate performance of high resolution electron microscopes depends on a variety of factors including the stability of the temperature surrounding the instrument. Variations in temperature can cause drift of the specimen, the microscope electronics, and the mechanical tolerances in components such as microscope lenses and scan coils. For high resolution work or for image reconstruction that requires acquisition of multiple exposures over extended periods of time, it is critical that the temperature variations be strictly controlled. A typical manufacturer's specification for temperature stability of a room housing a transmission electron microscope (TEM) is a tolerance of <0.5°C/hour with fluctuations of <0.05°C/minute. While modern instrumentation rooms are carefully designed to maintain stable environmental conditions (O'Keefe etal, 2004), it seems unlikely that these stringent specifications are routinely met in practice when the microscope is in operation and personnel are present in the room.

In the three decades following Castaing's seminal thesis [1] x-ray analysis received widespread attention from research groups. By 1980, the methods and correction procedures for quantitative analysis of elements with atomic number 11 and above, using accelerating voltages between 15kV and 25kV, were well established and available in commercial instrumentation. At the time, scanning electron microscopes (SEMs) could rarely deliver high and stable beam current at much lower kV, and x-ray spectrometers had poor efficiency below lkeV so that low kV analysis received comparatively little attention.

In the biomedical sciences, samples are mounted in a wide variety of media for examination by microscope. There are a wide variety of mounting media available with a correspondingly wide range of properties. Using the incorrect mounting medium may cause signal loss and optical aberrations; the correct mounting medium avoids such aberrations and preserves fluorescence signal with “anti-fading” properties. This article introduces mounting media for fluorescence microscopy, providing descriptions of their constituents and their properties, as well as accounts of users' experience

More detailed reviews of antifade reagents have been published by Ono et al. and Longin et al.. Papers describing the effect of refractive index (RI) mismatch have been published by Diaspro et al. and Hell et al..

The amazing growth of digital imaging in the past several years has blurred the line between "real" images and those that are digitally enhanced. In most of our movies and print advertisements, we see amazing effects that create images that look real but are not.

For the last several decades film has been the predominant method that scientists employ to record the images viewed through their microscopes. Film has been readily accepted as a valid, archival recording medium because it was difficult to alter once the exposure was made and the film or print developed. The improvements in computer power and image resolution, coupled with environmental considerations, have spurred the scientific community to replace photographic processes with digital images. Processes that took hours and days are now performed in minutes. Imaging programs like Adobe Photoshop can perform all of the same photographic steps that required a darkroom, and then can do much more. The image can be “burned” onto a CD or DVD disk which is difficult to alter. Printer technology has advanced so rapidly that inkjet prints rival photographic prints. Images are often distributed digitally and viewed on displays that continue to improve. As the hardware for digital imaging improves, the quality of digital images is approaching photographic quality for a fraction of the cost, and publication quality images are produced in a fraction of the time required for film-based photography.

The distribution of components, or microstructure, within a material is critical to its mechanical properties. For example, if a material has too many particles of one particular phase it may become too brittle, yet if there are too few particles it could lose strength. Every material exhibits different and unique characteristics. The goal of a material scientist is to analyze a material's microstructure and to optimize the manufacturing process. Electron microscopists observe this distribution on a very small, but critical, scale. The electron microscope can demonstrate specifically where the particles are distributed and then X-ray microanalysis can be used to identify what the particles are composed of.

This article will discuss the microstructure of an aluminum alloy with copper and iron additions. At the point of development, the mechanical properties of this new alloy were believed to be superior to that of previous materials; however, a number of subsequently conducted heat treatments did not support this theory, producing extremely unsatisfactory properties. In order to understand these results and rectify any problems, X-ray microanalysis was used to analyze the alloy's microstructure and assess the distribution of copper and iron particles within the metal.

This is the second in the series of short articles about Laboratory Information Management Systems (LIMS). This installment will focus on two issues - looking at ontologies and at business process design. The goal is to demonstrate how LIMS is really a combination of several capabilities, and that although each capability should be looked at separately, they ultimately must all work together as seamlessly as possible.

Before diving in, I would like to thank Dr. Q. C. Yu, the director of our Biomedical Imaging Facility here in Pathology and Laboratory Medicine at Penn http://www.med.upenn.edu/bmcrc/morph/?morph for his assistance, encouragement, and sponsorship of my participation in the Honolulu conference.

Freezing damages cell membranes and reduces the histological readability of biological specimens. This is a discussion of why, the consequences, and how to minimize or avoid the damage introduced when using freezing as the means to harden biological tissue in order to cut thin sections for histology.

Pure water can exist in the solid state in three forms. Two forms are crystalline: one with a hexagonal lattice and the other with a cubic lattice. The third form capitalizes on the fact that water can be frozen so rapidly that it does not have time to form a crystal lattice and remains amorphous (vitreous form). Crystal formation is responsible for the expansion of water as it freezes (a property unique of water), which creates specimen preparation artifacts. Vitreous ice does not expand upon solidification. This makes it the only desirable form of ice appropriate for biological specimens.