Recent Internet postings on the Microscopy listserver indicate paradoxical views on the personal protective equipment (PPE) necessary to handle liquid nitrogen (LN2) safely. Those views range from full protective gear to, somewhat facetiously, complete nudity. The crux of the paradox is that both extremes have points of validity.

The gist of preventing frostbite or cold injury to the skin is to prevent continuous contact with LN2. The physics of the Leidenfrost effect (LE) protects the skin from momentary contact or splashes of LN2. A layer of gas between the LM2 and the skin prevents significant heat transfer from the skin, stopping damage. The LE does not apply to inadvertent splashes of LN2 to the cornea. Alternatively, using protective equipment insulates the skin and prevents trapping of the cryogen by allowing the LN2 to run off.

If you want to collect X-rays on your SEM or TEM you have the choice of using an energy dispersive spectrometer (EDS) or a wavelength dispersive spectrometer (WDS). Which is better? That depends on what you want to do with it.

WDS is much more sensitive and has much higher resolution than EDS. Sensitivity means that WDS has a much lower minimum detection limit for trace elements. WDS can be up to several orders of magnitude more sensitive. This does not mean it is more accurate. Accuracy of analysis can be just as good for EDS as with WDS if the analyst takes the same care in sample prep, data gathering, and standardizing. Sensitivity simply means that WDS can detect much smaller amounts of a particular element than EDS. Why? Because the superior resolution provides much better signal to noise ratio than with EDS. Noise, in this case, is mostly contributed by background radiation from the sample. Because of its superior resolution, WDS can also resolve peak overlaps.

There seems to be a consensus among both the scientific and lay communities in according the highest rank, in terms of prestige, to theoretical scientists. This may seem justified because theoreticians understand the thought processes and activities of the experimentalists, the laypeople, and even the artists, excepting perhaps poets, but the reverse is not the case. Virtually nobody can understand the theoretician. Thus, in order of prestige, after the theoreticians come the experimental scientists and then the technologists, but the lowest on the totem pole are the designers of hardware, of scientific instruments. This towly rank does not seem to bother them, and they are happy in their field. As a matter of fact, many who earn royalties or actually manufacture the hardware are laughing ail the way to the bank.

Opticai and election microscopy have been used extensively as problem solving tools in the graphic arts industry. Atomic force microscopy (AFM) is a complementary tool to optical and electron microscopy - it provides a high resolution view of areas 150 mm by 150 mm and smaller, images may be viewed in three dimensions and imaging can take place in either air, under liquid, or in a vacuum.

AFM can be used for more than just the three-dimensional imaging of nanoscale features on a sample surface; it can detect friction, adhesion, compliance, thermal properties, and even magnetic signals. AFM images are stored digitally and so the data can be enhanced and viewed in many rays. Algorithms allow the display of a line profile across the image surface at any desired location along with quantitative height information. Average roughness data can also be calculated.

Los Aiamos Laboratory and VayTek, Inc. recently announced the development of a prototype far the “Scanning Computed Confocal Imager” or Virtual Pinhole Microscope. This breakthrough technology takes advantage of existing improvements in digital image systems, but configures functional subsystems in a novel way that eliminates many of the limitations and much of the expense associated with conventional confocal imagery.

One of the key elements of the new Imager is the use of a “virtual” aperture. The virtual aperture is implemented in software on a host computer, such as a penti urn-based computer or a Power Mac. It's possible, with this system, to adjust key parameters (such as effective aperture size) to optimize the image even after the basic data are acquired. Several algorithms have been used to produce images similar to those acquired through conventional confocal microscopy.

As if lifted from the script pages of a previously aired installment of the popular Friday night “istherelifeoutthereism”, one group of microscopic parasitic trematodes will puncture, overrun and terrorize not one, not two, but three distinct and disparate hosts to survive and breed. Known as the Ascocotyle complex of trematode worms, these well-designed hitch-hikers sport a crown of one (Figure 1) and sometimes two rows of 15-20 spines surrounding a very muscular oral sucker (Figure 2), as well as a ventrally placed body sucker and a full complement of smaller, but sharp, body spines (Figure 3), which they employ to prevent easy dislodging from their intended host. The life cycle for these brackish water travelers begins in a brood sac developing within amnicolid snails (such as Cerathidia) which graze the bottom of tidal marshes and ingest the trematode eggs.

The cutting-edge tool for IC fab support and defect review brings together the Focused Ion Beam (FIB) technology with the Scanning Electron Microscope (SEM) into a single workstation. The twin beam FIB/SEM workstation, FEI Company's DualBeam™ 820 for example, combines the unique micromachining, microdeposition, and analysis capabilities of a FIB with the high resolution imaging power of a Schottky field emission scanning electron microscope (FE SEM). The full functionality of both instruments is available and neither is compromised by the other.

A microscopist is presented with a special problem when asked to characterize a population of particles. In order to adequately describe the sample, it may be necessary to examine hundreds or even thousands of individual particles, recording the size, shape, identity or other parameters of interest. To manually characterize a statistically significant fraction of the sample could require many hours of tedious work at the scope, followed by still more tedious hours of data reduction. What is needed is a technique to automate the repetitive parts of this process: the recognition and characterization of particles in the sample and the reduction of data and presentation of results. This technique is automated particle analysis.

What is combinatorial chemistry? Combinatorial chemistry is quickly becoming a very popular technique for organic synthesis in the pharmaceutical and biotechnology fields. Basically, combinatorial methods allow one to obtain thousands of derivatives of chemical compounds in a very quick and efficient manner. The method begins when a molecule of interest is attached to resin beads. Once the molecule is attached, a number of reactions can be run on the beads. The beads can be split up into several subsets, and different reactions can be run on each of the subsets. Because the beads are in the solid phase, it is extremely easy to separate the beads from the liquid layer after the reactions have completed.