The Microscope - Volume 57, Second Quarter 2009

IN THIS ISSUE:

On the cover: This High Dynamic Range (HDR) photomicrograph of properly exposed sand grains was constructed from four similar images of varying exposure values by combining the “best” exposure areas from each image. See Criteria for High Dynamic Range (HDR) Imaging of Photomicrographs.

Editorial | Rebirth of the International Microscopical Society?

Gary J. Laughlin
The Microscope, 57 (2), p ii, 2009.
Excerpt: Leafing through the pages of the New York Microscopical Society Yearbook, 1964, I happened upon a list of microscopical societies with brief descriptions of their history, mission and activities. Represented were some that most of us have heard of, the majority of which are, fortunately, still active today. This distinguished company includes NYMS, RMS, Queckett, SMSI, San Francisco, American, Mikroskopische Gesellschaft Zurich, Reading, Leidy, Electron Microscope Society of America (now MSA), Biological Photographic Association, and others. But one group struck me as unfamiliar: The International Microscopical Society (IMS). Full article (PDF)

Distinguishing Coal, Coke and Other Black Particles

J.R. Millette, R.S. Brown, J.P. Kyle, W. Turner Jr., W. Hill, and W.R. Boltin
The Microscope, 57 (2), pp 51-57, 2009.
Abstract: Particles of coal (anthracite, bituminous, and lignite) and coke can be distinguished from other black particles based on light microscopy examination. It is possible to distinguish between coal and petroleum coke particles based on their elemental composition as determined by electron microscopy X-ray analysis. This paper provides some background information about each substance and augments the information in The Particle Atlas (published by McCrone Research Institute) about the particle characteristics as determined by light and electron microscopy. Example micrographs and X-ray elemental spectra of particles of coal and petroleum coke are included. Full article (PDF)

Criteria for High Dynamic Range (HDR) Imaging of Photomicrographs

Rich Brown and Ben Zipperer
The Microscope, 57 (2), pp 59-62, 2009.
Excerpt: With the passing of film and the acceptance of digital cameras, exposure techniques (hardware and software) have been developed to improve the quality of digital images. As computers process more data faster, the software used for image processing becomes cheaper, faster and easier to use. Specifically HDR, or High Dynamic Range imaging, has the potential to increase the range of contrast in images taken with a digital camera on a copy stand, tripod or with a stereomicroscope by combining multiple exposures and taking the “best” exposure from each area of the image. Full article (PDF)

The Microscope of Linnaeus and His Blind Spot

Brian J. Ford
The Microscope, 57 (2), pp 65-72, 2009.
Abstract: Carl von Linné (Linnaeus) was the pioneering taxonomist of the 18th century. His microscope survives along with the collections at his former residence in Sweden, though little has been known about it. The instrument is here described and its performance is demonstrated. Curiously, Linnaeus showed little interest in, or knowledge of, microscopic organisms. Very few of his drawings portrayed minute structures and examples of those that survive are described. We also review Linnaeus’s little known booklet on microorganisms. Full article (PDF)

Dispersion Staining of Sugars

Jeffrey M. Hollifield and Ian Kelsay
The Microscope, 57 (2), pp 75-81, 2009.
Abstract: A variety of sugars is present in pharmaceutical products, illicit drugs, foods, explosives, and many other items commonly encountered by forensic laboratories. This paper begins with a few common spot tests for sugars, and a brief review of the dispersion staining technique and the theory behind it. Applications of dispersion staining are discussed, and the optical data for selected sugar compounds are presented in table form. Dispersion staining liquids suitable for sugar analysis are recommended, and a chart correlating dispersion staining colors to sugar identification is included. Full article (PDF)

Tricks Of The Trade: Cleaning a Microscope’s Field Diaphragm

Meggan King and Sebastian Sparenga
The Microscope, 57 (2), pp 83-86, 2009.
Excerpt: If you have ever looked closely at a field diaphragm or taken one apart, you will notice that it is a complicated puzzle, and careful attention needs to be paid to exactly where things go. One leaf out of place and it will no longer be functional. We were a bit apprehensive about removing the field diaphragms, dumping out all of the leaves and trying to put them back together. Many have tried, few have succeeded! Full article (PDF)

The Microscope Past: 25 Years Ago – Plastic Embeddment of Dry-Processed Tissue

Lawrence K. Yatsu
The Microscope, 57 (2), pp 87-91, 2009.
Abstract: Seed tissue is extremely difficult, if not impossible, to embed in plastic when fixed and processed dry; on the other hand, if it is fixed with aqueous fixatives and dehydrated by solvent exchange, seed tissue can be embedded readily. Earlier, I hypothesized that cell walls exclude resin monomers from dry-processed peanut (Arachis hypogaea L.) seed tissues. Now I show that seed tissues whose cellular contents have been digested away by a proteolytic enzyme, still are difficult to embed in plastic if air-dried and processed dry. I submit, therefore, that since these specimens consist only of cell walls, air-dried cell walls are indeed the factor that bars passage of resin monomers into seed tissues processed dry. Full article (PDF)