Atomic force microscopy (AFM) has proven to be very useful to material scientists and physicists. Biologists are only beginning to utilize the potential of this methodology. In a recent article, Tatsuo Ushiki, Jiro Hitomi, Shigeaki Ogura, Takeshi Umemoto, and Masatsugu Shigeno reviewed the applications of AFM to biologic studies.

They began by reviewing the basic principles of AFM, emphasizing the value of the non-contact mode for visualizing the relatively “soft” surface of biologic specimens. They presented some examples of biologic images: DNA, chromosomes, and collagen fibrils. The specimens examined with the AFM did not need to be coated, theoretically offering a view with a smaller potential for artifacts. AFM images have the advantage of containing quantitative information about the sample height.

In the past, I have used mountants such as DIATEX (which is a synthetic mountant of 40% acrylic resin solids, and 60% toluene), or Canada Balsam in xylene for general purpose mountants. If a tight seal of resin forms around the coverslip, the prep is usually good for some time and may last indefinitely. However, the center of the prep still contains resin mixed with solvent that has not had a chance to evaporate, If the solvent continues to evaporate slowly from the prep, large air bubbles will replace the solvent and ruin the prep.

Secondary (SE) and backscattered electron (BSE) signals in the SEM provide high resolution monochrome images. BSE signal strength is modulated by mean atomic number and ‘false” colour can be introduced to enhance material contrast. Colour can also be introduced using multiple SE detectors, each with a different sensitivity to topographic and compositional information: by controlling signal mixtures and colours, the operator effectively has access to a powerful “studio” to generate aesthetically pleasing colour images. In both these examples, the correspondence between local elemental content and colour is entirely arbitrary and under subjective control of the operator, Elemental x-ray maps can be acquired and combinations colour coded to reveal phase distributions. For large numbers of maps and images, chemometric techniques such as PCA may be used to discover common relationships and assist the process of colour coding. Images derived from x-ray maps are usually low resolution and the analyst has to decide which elements to include and do a fair amount of data manipulation before any conclusions can be drawn.

Rotary vacuum pumps are used in virtually every research lab, especially those engaged in vacuum science such as electron microscopy and mass spectrometry. In the majority of these situations the exhaust can and should be vented to the outside. Unfortunately, many labs lack this capability. Oil mist vapors emitted from pumps under a load can be quite annoying and may be a potential health hazard. Pumps located in small confined spaces such as microscope rooms, darkrooms, etc. are particularly a problem. Often the manufacturer supplied filters are either inadequate or poorly maintained.

The recent completion of a company-wide PC network system, supported by network servers intended to rapidly handle large data files from CAD systems, made implementation of digital imaging in the Corporate Materials Engineering laboratory of Case Corporation a wise investment. Laboratory reports in Microsoft Word with linked image files can be rapidly received through any of the networked PC's and are archived in the server system. The changeover from film imaging to digital imaging was very sudden. This change was accelerated by satisfied users, whose work was made easier and more productive, and satisfied customers within Case Corporation.