Chasing sources of vibration seems to be a never-ending problem in microscopy. Here are the approaches we've taken to two different sources of vibration affecting our Hitachi S-800 FESEM. One of the first problems was with a window air conditioning unit in the room that was needed to augment our so called central system. The existing window unit vibrated the window, walls, and floor. One solution may have been to buy a split unit so that the compressor was outdoors, but there was a moratorium on buying new air conditioning units

With today's requirements for chemicals and reagents in research and clinical laboratory environments, questions often arise concerning expiration dating. Why are not all chemicals and reagents expiration dated by the manufacturer when they are made? How should expiration of chemicals and reagents not dated by the manufacturer be determined? How would a laboratory establish expiration of solutions and reagents prepared in-house?

To assure good manufacturing practices, many manufacturers comply with guidelines set for them by agencies such as the International Organization for Standardization (ISO) and are inspected by ISO auditors. Some manufacturers are required to comply with the Food and Drug Administration (FDA.) These manufacturers are known as GMP facilities (good manufacturing practices) and are assessed by FDA inspectors. Like regulatory agencies who govern clinical sites, ISO and FDA require manufacturers to establish uniform quality systems for product testing and certification.

We've used gelled agarose to cover & hold monolayer cells in place when treatment leads to cell lifting. Low-gelling temperature agarose (Type VII) (Sigma A 4018 or A 0701) can be made as a 2% stock solution in “phosphate-buffered saline” (PBS) (boiled then kept at 42° C to remain liquid).

The resurgence of microscopy in recent years is certainly not news to readers of this journal. But, for many of us, this resurgence has placed additional strains on our already busy lives to keep current on new technologies and techniques. Fortunately, books such as “Imaging Neurons. A Laboratory Manual” (Edited by Rafael Yuste, Frederick Lanni and Arthur Konnerth) provide comprehensive and timely reviews to help us keep abreast of the field.

The book evolved from a summer course taught by the editors and many of the contributors at the Cold Spring Harbor Laboratory, and although it obviously targets neurobiologists, many of the techniques are applicable to other biological systems. An impressive feature of the manual is the breadth and detail of topics covered.

Diatoms make for beautiful specimens for both transmission and scanning electron microscopy. As well, they are studied by many people, and there is always a need for good diatom preparations for EM.

I find that the diatoms in diatomaceous earth are usually broken, and like to prepare my own from fresh specimens. The materials needed for this are a plankton net, some potassium dichromate, and 30% hydrogen peroxide. Once the diatoms are collected (plankton net tows from shoreline, or wherever), they can be cleaned using the chemicals.

Since Blum discovered its hardening properties in 1893, formaldehyde has become the most widely used fixative in the world for specimens to be examined by light microscopy. However, since most commercial preparations of formaldehyde contain methanol, a protein precipitant, formaldehyde has been considered an unsatisfactory fixative for tissues to be examined by electron microscopy.In 1973, Carson et a/, described a parallel study comparing the electron microscopic results of fixation with paraformaldehyde vs. formaldehyde. They found that there was no difference in the preservation of ultrastructural morphology provided that the buffer systems were identical. In 1976, McDowell and Trump described a fixative combining commercial formaldehyde and glutaraldehyde (4CF-1G). Both of these fixatives are dual purpose fixatives and preclude the selection of tissue for electron microscopy prior to fixation. They can both be prepared in large quantities and used for routine surgical specimens.

Questions often come up concerning the best way to prepare powders for electron diffraction analysis in the TEM. This is actually fairly simple:

• 1) Take an oxide powder, grind it up with mortar and pestie and take a carbon coated grid and swipe it across the fnes. Two glass slides can also use to grind up the powder.

• 2) A number of materials can be evaporated onto a carbon coated grid or onto a cleaved NaCI sample and then float that off on water onto a grid.

• 3) A molybdenum wire can be smoked in air to provide crys tals. If the wire is left in the smoke long enough, there will probably be enough crystal to cover a grid. Heat the wire across the terminals of an evaporator or heat with a torch to generate the white smoke. Thus MoO3 sample will pro- vide a good rotation calibration sample. Magnesium can also be burned to produce MgO crystals.

Rough trim the excess plastic from the specimen face with a razor blade, keeping all the tissue edges. Put the specimen chuck into the microtome arm, and put in a dry glass knife. Shave off enough plastic from the front (face) in very small increments (start with 1 μm slices, decrease to 0.5 μm, then 0.1 μm until you get a mirror smooth face). If you must keep all the sample, then start with a very thin shaving just to get the face smooth. You should be able to tell when you are into the tissue by looking at the thin shavings. Mark the top edge of the one that will become the top of your trapezoid-with a magic marker on the chuck.

DRS Hadland, formerly Hadland Photonics, has supplied the Department of Measurement, Control and Microtechnology at the University of Ulm with an ultra-high speed digital imaging system to help them gain a greater understanding of the dynamics of moving parts in microdevices.

The measurement of position, velocity and acceleration of moving parts in microdevices is of great interest in the rapidly growing field of microsystem technology in order to solve the problems needed to allow evolution from laboratory use into industrial mass production. Such research is targeted towards gaining a better understanding of the dynamics of the moving parts in microdevices.

For the visual investigation of dynamics in microdevices high optical magnification is necessary because the dimensions of microsystem components are very small. Therefore, velocities of parts of such microdevices appear to be extremely fast and time constraints are very small.

This article describes a simple, economical modification of the standard stage insert used on the Nikon TMD, Diaphot and E800 models of inverted microscopes to support slide securely without lateral motion or sample compression. The central portion of the stage on these popular microscopes consists of a removable insert that provides sample support and demarks of the imaging area. The insert may be replaced with holders for a variety of culture chambers and other specialized sample supports. This unique design contributes to the adaptability of these microscopes for a wide range of imaging applications such as confocal microscopy, calcium imaging and electrophysiology.

The standard insert is actually constructed of two pieces, an outer ring and a central plate (Figure 1A). The central plate is removed from the modified ring, which is then used in the inverted position (Figures 1B, 3, 4).

Make up 0.2% sodium lauryl sulphate (a detergent) in distilled water. Grids are dipped in this just prior to collecting sections, then drained on filter paper before introducing under the water in the knife boat and bringing up under the sections. The sections can be manipulated along flimed slots with an eyelash before the residual film of water dries. You can play this game under the binocular microscope for some minutes while watching the water evaporate. Its a bit like watching paint dry!

Sometimes, raising the water meniscus (i.e., to convex) is useful when trying to position sections prior to collection.

Too much carry-over of detergent can cause the sections to run together and bunch up, this is a surface tension effect of the detergent.