With such topics as ISO-9000, TQM (Total Quality Management) and with the Maicolm Baldridge Quality Award being mentioned these days, it may not be long before instrument calibration becomes an issue in your laboratory. Among the many important areas governed will be magnification accuracy of optical microscopes, TEMs, and SEMs, The following brief discussion probes the rather complex subject of SEM magnification accuracy.

With an increasing interest in both immunological procedures and elemental (ion) detection, it is imperative that tissues be preserved in as life-like a state as possible. Up until now the only type instrument available for in situ cryo fixation was various configurations of cryopliers which lacked the ability to control freezing variables. With the introduction of the PS1000 (Delaware Diamond Knives, Inc.), a pneumatically operated hand held slammer, it is now possible to reproducibly fix in situ as well as in vitro and achieve results seen previously only with table top instruments. This instrument is designed to provide a consistent delivery rate through the use of a pneumatically operated piston.

The availability of such an instrument, clearly improves the accuracy of many investigations. Pleural fluid of the lung parenchyma (Figure 1) has been preserved in its natural state (i.e., filled with air). Figure 2 shows a proximal tubule of rat kidney which has been crycgenically preserved in situ. Applications in biological research, materials science and clinical pathology are currently being investigated at several major institutions.

The attachment of devices to the eyepiece of a microscope is a long accepted practice among microscopisis; almost as soon as a new technical advance appears, someone is adapting it to the study of microscopic specimens. Photomicrography was in use from almost the earliest days of photography, while the microspectroscope was developed and described by Sorby as early as the 1860's. As advances in technology provided improved means for recording data and collecting radiation invisible to the human eye, these were rapidly adapted to the microscope as add-on accessories constructed as one-of-a-kind instruments or in a few cases as commercial products.

Firearms are involved in roughly 60% of all murders, 33% of all robberies and almost 25% of aggravated assaults. Given these statistics, it is easy to see why a determination of whether an individual has recently been in the immediate vicinity of a discharged firearm is important to law enforcement.

The epoxy resins, especially Spurr's epoxy resin, are time consuming to prepare and dangerous to work with. In an effort to minimize contact time with the resin and to conserve components, we prepare one large batch of resin (minus catalyst) that is then dispensed into glass scintillation vials that are tagged to give the exact weight of resin in the vial, The resins are stored in the freezer (preferably -70° C) until needed at which time they are thawed and the appropriate amount of catalyst added. After mixing by gentle inversions and stirring, the resins are dispensed as needed using widebore pipettes. .Any resin remaining in the vial may be refrozen several times after adding a puff of Freon or dry air to the via!. When the resin becomes too depleted or too old to refreeze, the vial is placed into a 60° C oven and the contents polymerized. The vial may then bs discarded or recycled (i.e., reused) untii the space in the vial is diminished to an unacceptable level.

Developments in space exploration, microelectronics, and other high-tech industries have promoted cleanroom technology and increased the need to identify particles sometimes too small to handle with the polarizing light microscope. Light microscopy has traditionally been the most commonly used technique for small particle identification and many microscopists are very proficient in identifying particles using a polarizing light microscope as the principal investigative tool. The polarizing light microscope, in the hands of a good microscopist, is an extremely efficient instrument for particles down to a few micrometers in size. However, in the size range below 5 pm, an instrumental approach to small particle identification is essential. The development of electron microbeam instruments in the early '60s and 70s introduced a new dimension to small particle identification. In these instruments, particles of 1 urn and smaller can be chemically identified when chemical characterization of particles is combined with cathodoluminesence and a relatively simple optical characterization in the instrument itself.

The Photon Tunneling Microscope is used to provide high resolution (subnanometer vertical), quantifiable, real-time, 3-D (with continuously variable viewpoint) imaging and profilometry of homogenous dielectric samples, whether transparent or absorbing. A partial list of these includes: thin films (micraroughness. damage evaluation, step height) optical storage media (pit depth and shape measurement), magnetic media (microroughness, wear tracks), polymers (surface characterization), optical surfaces (microroughness, damage, polishing evaluation), diamond-turned optical surfaces (tool and machine characteristics from surface topography), binary optic surfaces, porous silicon structure, photographic grain analysis, replicas of metal surfaces, microlithography evaluation, and manufacturing web evaluation (film base, magnetic media base).

The Biological Images Project is the culmination of the four summers I have spent at Apple Computer. In short is is a software package which allows students to manipulate and explore biological images (i.e. micrographs, CTs, MRIs, etc.), Consisting of four sections - interface, biological images, image processing, and communication software - this package can serve as a powerful educational medium. The interface supports the more traditional forms of teaching - textual notes and brief lectures. The collection of biological images allows students to visualize biological structures in ways they never have before and exposes them to a variety of scientific techniques and tools. Image processing lets the student interact with the images, to manipulate, explore, discover and in some ways gain ownership of the image. Finally the communication package will provide the students a medium to share their discoveries in an interactive manner and submit them to peer review.

A confocal laser scanning microscope which can collect images in both transmission and reflection modes has been installed and is being tested in the Imaging Laboratories of the John P. Roberts Research Institute, London, Ontario. Designed by Dr. Ted Dixon at the University of Waterloo, it is being developed by a multi-disciplinary research group which includes the Ontario Lasers and Lightwaves Research Centre and the Department of Physiology, University of Toronto; the Radiology, Physics, and Pathology Departments, MacMaster University; and the Zoology Department, University of Western Ontario.

Commercial confacal microscopes operate by reflectance or epifluorescence. A pair of scanning mirrors direct a diffuse laser beam in a raster pattern through an objective lens, which focuses it on the specimen. Reflected light passes back along the same light path, being “de-scanned” by the moving mirrors and then diverted by a beam splitter into a detector. On its return to the detector, light from the focal plane is focussed through a pinhole, which blocks light from out-of-focus regions of the spectrum The microscope stage is moved up and down by a stepping motor to collect images at different depths.