The Microscope - Volume 67, Second Quarter 2019
IN THIS ISSUE:
On the cover:
Selected photomicrographs of some particles that microscopists should know or learn to identify. Left, from top to bottom: pine pollen, nonconiferous chemical wood fibers, and RDX explosive. Right, from top to bottom: dyed viscose rayon fibers, diatomaceous earth, and human hairs. See Editorial, What Every Microscopist Should Know (Take the Challenge): the Results, page ii. (From The Particle Atlas, Edition Two, prepared by John Gustav Delly and Walter C. McCrone, 1973 – 1979)
Editorial | What Every Microscopist Should Know (Take the Challenge): the Results
Gary J. Laughlin
The Microscope 67 (2), p ii, 2019
Excerpt: A year ago in this column (The Microscope, 66:2, p ii, 2018), we challenged readers to list their Top 10 choices of particles from various substance classes that every well-rounded microscopist encounters regularly and should be able to identify. For brevity, here are the results for the Top 5 in each category, in random order. Special thanks to Oppenheimer Goldberg of Scottsbluff, NE for his thorough contribution to the challenge.
The Role of Collections in Trace Evidence
Christopher S. Palenik
The Microscope 67 (2), pp 51 – 64, 2019
Abstract: In the discipline of trace evidence, collections and databases have been largely developed in an ad hoc manner, often based upon the topical questions that arise in the course of casework. The wide variety of materials encountered in this discipline, the wide range of data that may be collected from a given sample, and the relatively low frequency in which a given sample may be consulted in direct reference to a case are some of the considerations that have limited the development of more formalized collections. This article on collections in trace evidence aims to illustrate the broader range of benefits that collections and their associated datasets can provide to the forensic science community, not only in casework, but also in training and general experience.
Hacking a Dinosaur: Upgrading a Vintage Microscope with the Raspberry Pi
The Microscope 67 (2), pp 65 – 74, 2019
Abstract: Vintage microscopes have occasionally surfaced on the surplus market. With some effort, these scopes can be rebuilt to retrofit them for photomicrography with commercial hardware. Although this can be challenging, the availability of low-cost, single-board computers, camera peripherals, PVC fittings, and some programming experience, an older compound microscope can be upgraded to capture quality images and video. Using a Raspberry Pi 3, an open source hardware and software platform, a digital imaging system can easily be retrofitted for less than $75.
Critical Focus | When the Microbes Take Command
Brian J. Ford
The Microscope 67 (2), pp 75 – 81, 2019
Excerpt: Scientists rarely realize that parasites can take over our brains and control our lives. Instead of prescribing sedatives to keep us calm, perhaps doctors should treat these infections.
Searching for the Spermatozoon: A Historical Review of Identification Techniques
William H. Wilson
The Microscope 67 (2), pp 83 – 95, 2019
Abstract: Although the existence of the spermatozoon was first noted more than 300 years ago, the understanding of its function, physicochemical structure, and viability is a relatively recent discovery. The structure of the sperm is distinctive: it is composed of an oblong-shaped head, a neck, a midpiece, and a flagellating tail, and is approximately 50 – 75 µm long. Seminal fluid is gelatinous and sticky, and is composed of water, salts, organic matter, proteins, and lipoids in an alkaline state. Dry seminal stains appear grayish-white, and impart a stiff, starchy feeling to an absorbent material. Methods for detection of these stains include tactile and chemical tests, ultraviolet light or alternate light sources, and microcrystal tests, although noted nonspecific interferences exist for these methods. Recovery procedures of dry stains include cutting, scraping, and immersion, and acidic destruction or sonic oscillation of the substrate cloth. Unstained sperm may be microscopically detected, but may be confused with Trichomonas vaginalis or other interferences to the untrained eye. Chemical staining is utilized in order to aid in sperm identification by individually coloring the acrosome, nucleus, and/or tail. Staining, counterstaining, and other procedures for the purpose of identification are described here.
Afterimage | Spider-Man Tape
The Microscope 67 (2), p 96, 2019
The patterned ink dots from a printed image of the superhero Spider-Man on a piece of duct tape; transmitted light, field of view is ≈1 – 2 mm.
Copyright © 2019 Microscope Publications, Division of McCrone Research Institute. All rights reserved.