Recently, I had a delightfully pleasant surprise. I was attending a Human Embryology Conference in Washington, D.C., held at the National Museum of Health and Medicine, a Division of the Armed Forces Institute of Pathology. I've heard of the AFIP many times, but I had never been there, didn't even know where it was located. AFIP is located on the campus of Walter Reed Army Medical Center, which is bordered by Georgia Avenue. If you're driving, it's near the Maryland state line. If you're taking the Metro, get off at the Silver Springs stop and take a taxi.

Science educators in K-12 schools are often confronted with skepticism when the budgetary needs for equipment and materials come up for discussion. They are expected to make science “interesting”, “exciting”, “motivating”, and “up-to-date”, but without investing money in modern technology. It is important to not let this common fascination with novelty, excitement and parsimony, prevent us from realizing the full potential for videomicroscopy in classroom science teaching. In addition to their “gee, whizl” aspects, videomicroscopes offer a number of instructional advantages that make them worth the money, and I will present some ideas about how to use and configure a videomicroscope for classroom use.

Improvements over the past few years in essentially all modern operating systems coupled with the blurring of the boundaries between mainframes, workstations, and personal computers make the choice of platform often one of personal preference other than of necessity. A decade ago there were very distinct differences between the features offered by IBM PC and clones, the Apple Macintosh, and UNIX workstations. These differences included price, processing performance, OS features, look and feel, graphical capabilities, memory and disk limitations, networking capabilities, ease of- use, system stability, development tools, etc. Since then many of these distinguishing differences have evaporated making platform selection a more subtle issue, but also much less important. However, there are still a great many users thai tend to make such decisions based on their “religious” preference of platform rather than based on objective information.

Colloidal gold has been used for centuries in the preparation of stained glass for windows and fine glassware. In recent years, colloidal gold particles have become a useful tool in microscopy for staining tissues and sections. Colloidal gold particles are especially useful for biological electron microscopy, Some of the reasons why are listed below.

1. * Homogeneous preparations of particles varying in size from 3μm to 20μm can be easily prepared.

2. * Colloidal gold suspensions are inexpensive to prepare. Most proteins can be easily coupled to colloidal gold particles.

3. * Most proteins can be easily coupled to colloidal gold particles.

4. * Proteins coupled to gold particles do not appear to lose their biological activity.

5. * The colloidal gold particles can be easily seen in the electron microscope.

6. * Colloidal gold does not naturally occur in biological material. Therefore, if you see it, it is because you put it there.

7. * Colloidal gold probes can be used for light microscopy, The larger gold particles can be directly observed by the light microscope. Small particles are detected by silver enhancement or epipolarized illumination.

8. * The same probes can be used for both LM and TEM imrnunocytochemistry.

These are perhaps the most fundamental interactions of light with matter, since they must often precede some of the other interactions described later. A good account of most of these will be found in the book by Slayter (1970). When light falls upon an object some of it will be reflected, some of it absorbed, and the remainder will be transmitted, phenomena which are familiar from everyday life, Most of the objects we observe are seen by the light that they reflect towards the eye, and their different surface appearances depend on the nature of this reflection. Some objects are transparent, enabling us to observe them by virtue of the light that they transmit - wine in a glass, church windows and colour transparencies are obvious examples.

Advances in computer processing power have enabled new threedimensional image enhancement and visualization techniques. Data storage capacities of a gigabyte or more are affordable and commonplace. The Power Macintosh computers are RISC based processors which perform graphical and computational tasks many times faster than the older 68000 based systems. These new systems are ideal platforms for threedimensional deconvolution of microscope data sets.

The underlying mechanisms whereby cells sense and respond to external stimuli are not well understood, but for some time it has been known that the extracellular matrix has an influence on the behavior of cells. For example, changing the flexibility and/or adhesiveness of the matrix can change the shape of cells, and determine whether or not they continue to divide or begin to differentiate. Recently, in a series of elegant experiments, a group of cell biologists in Boston have demonstrated the presence of an interconnected molecular network pervading the entire living cell, extending from its outer surroundings into the genes in its nucleus.

The most unusual use I've seen for an SEM was as a special-effects generator for the fifth Star Trek movie, “The Final Frontier”, William Shatner directed the film as well as starring in it. He chose Bran Ferren of Associates and Ferren, now part of Disney Imagineering, to do the special effects. Ferren had the idea of using SEM imagery for the “eerie planet in the center of the galaxy”, because the large in-focus depth of field gave an unearthly feel to the scene. Shatner was fascinated by the technology and the resulting images.

When you hear that a film cost $50 million to make, here's how it happens. They bought a Zeiss 960 SEM and a PGT IMIX system just for that one sequence in the movie! A mainstay of movie effects is model animation, in which miniatures are dragged along suspended wires while one or more cameras (mounted on articulated robotic booms) also move to produce She complex and realistic action you see on the screen.