The Microscope – Volume 71, Second Quarter 2024
IN THIS ISSUE
On the cover
Pioneer microscopist Robert Hooke included this exquisite microscopical study of a leaf of the stinging nettle Urtica dioica in his book Micrographia of 1665 (top). This year, Brian J. Ford used SEM and Photoshop to carefully correlate his modern specimen (bottom) and align the stinging hairs to match those of Hooke. This provides for us how the nettle leaf appears to a modern microscopist and, more importantly, how it appeared to Hooke, unrefined and not idealized, just as he published it in the 1600s (Photos: Brian J.Ford).
Editorial | Calling All Authors
Gary J. LaughlinThe Microscope 71:2, p. ii, 2024https://doi.org/10.59082/FVFF8387
Excerpt: With a few decades of experience behind us now and nearly a full calendar year to prepare, working together, we successfully completed delivery of a full Inter/Micro microscopy conference schedule, as big and successful as ever before. And more than ever, I can’t say enough about how grateful all of us at McCrone Research Institute are for each of the authors, presenting authors, attendees, students, and sponsors, who made Inter/Micro 2024 a truly enjoyable meeting.
Inter/Micro 2024 — International Microscopy Conference
Gary J. LaughlinThe Microscope 71:2, pp. 51–63, 2024https://doi.org/10.59082/IVDK7006
Abstract: McCrone Research Institute hosted the annual Inter/Micro microscopy conference on June 11–14, 2024. This was the 76th anniversary of these meetings since they first began here on the South Side of Chicago in 1948. Professional and amateur microscopists from around the world gathered together to meet and present their latest research and advancements in new techniques, instrumentation, and practical applications in various fields of microscopy and microanalysis. The two-day author presentation schedule was followed by a two-day practical workshop on how particles of combustion are identified along with their sources.
An Inexpensive Reflected Darkfield Epi-Illuminator for a Standard Polarized Light Microscope
Russ Crutcher, Heidie Crutcher, and Hayen BettesThe Microscope 71:2, pp. 64–68, 2024https://doi.org/10.59082/GFQH4700
Abstract: The analysis of environmental particles often requires reflected or epi-darkfield illumination. For example, an opaque spherical particle might be a cenosphere from a diesel engine, a fungal spore, a toner sphere, insect frass, a paint sphere (of any color), flyash,or a magnetite sphere, just to name a few possibilities. Reflected darkfield illumination and the ability to quickly change the type of illumination without moving the slide removes the uncertainty. The assessment of combustion residues in environments exposed to smoke from a fire has been plagued by the assumption that discovery of opaque particles equates to discovery of combustion residue. For the microscopist, the absence of immediately available reflected darkfield illumination and the inability to change the type of illumination quickly without moving the slide is a critical flaw in the analysis. There is a relatively inexpensive solution to the first problem, i.e., a darkfield epi-illuminator, using LED technology, designed to fit on a standard polarized light microscope (PLM) objective.
The Preparation of Tape Lift Samples for the Study of Subvisible and Nanoparticles
Christopher S. PalenikThe Microscope 71:2, pp. 69–76, 2024https://doi.org/10.59082/KGWG5997
Abstract: Tape lifts are commonly used as a substrate for the collection of microscopic trace evidence. While traces such as fibers, glass, and paint can generally be readily recognized by stereomicroscopy, these larger particles often represent a minor, to trace fraction of the total particulate load on a given lift. In contrast, smaller particles (broadly categorized as dust), which are frequently the dominant component on the tape, are less commonly exploited as forensic evidence. These particles, which for the purposes of this article, may range in size from hundreds of micrometers down to nanometers (i.e., subvisible) are difficult, or sometimes impossible to see, much less characterize, by stereomicroscopy. Such particles also present challenges to isolate, manipulate, and analyze. In addition, when collected on tape lifts, as is the case in many forensic examinations, such particles become trapped in an adhesive matrix, further complicating attempts to isolate all but the largest particles for subsequent analyses.
Abstract: Tape lifts are commonly used as a substrate for the collection of microscopic trace evidence. While traces such as fibers, glass, and paint can generally be readily recognized by stereomicroscopy, these larger particles often represent a minor, to trace fraction of the total particulate load on a given lift. In contrast, smaller particles (broadly categorized as dust), which are frequently the dominant component on the tape, are less commonly exploited as forensic evidence. These particles, which for the purposes of this article, may range in size from hundreds of micrometers down to nanometers (i.e., subvisible) are difficult, or sometimes impossible to see, much less characterize, by stereomicroscopy. Such particles also present challenges to isolate, manipulate, and analyze. In addition, when collected on tape lifts, as is the case in many forensic examinations, such particles become trapped in an adhesive matrix, further complicating attempts to isolate all but the largest particles for subsequent analyses.
Reducing Confusion in Refractive Index Determination by Adapting the Chart from Figure 5-9 in Optical Crystallography by Bloss: A Technical Note
Wayne Moorehead
The Microscope 71:2, pp. 77–79, 2024
https://doi.org/10.59082/NZNM9078
Abstract: Identification of unknown particles using the immersion method with a polarized light microscope was taught in a tier one university forensic microscopy course using Optical Crystallography by F. Donald Bloss as the foundational text for understanding the theory of optical properties observed in the microscope. A chart from the text, Figure 5–9, was confusing to students.By inverting the chart, the students’ observations of optical properties appeared more consistent with the information contained in the chart. Thus, this revised, inverted chart is more useful toward determining the refractive index of an unknown particle. View or download a high-resolution PDF of the new chart, Figure 5-9 (adapted by Moorehead) from Bloss, Donald, (1999). Optical Crystallography, 40. Mineralogical Society of America: Figure 5-9 (adapted)
Estimating Time of Mold Growth in an Indoor Environment
Payam Fallah
The Microscope 71:2, pp. 80–83, 2024https://doi.org/10.59082/YMBU9865
Abstract: Mold growth (not spores) on surfaces indicates the presence of moisture in an indoor environment at some point in time. Mold proliferation is merely the direct consequence of moisture intrusion. Direct microscopical examination is the primary method to determine if mold or other fungi have grown on a particular surface. This analysis, while generally straightforward, provides the important answer to the question of whether mold growth is present. The growth can be described as the presence of vegetative structures (hyphae or mycelium) with or without associated spores or sporulating structures.
Critical Focus | What Could the First Microscopists See?
Brian J. FordThe Microscope 71:2, pp. 84–95, 2024https://doi.org/10.59082/KQVK8045
Excerpt: We all remember key dates. Top of the list? It’s July 4, 1776, when the Declaration of Independence was signed so the U.S. became a nation in its own right and set the time for a huge annual party of fun, feasting, and fireworks. Here’s another for you: September 7, 1674. It’s the day science met the microbe. On that date, Antony van Leeuwenhoek, the draper of Delft, penned a letter to London. He told how he’d recently returned from a trip by boat across a nearby lake and had collected a small glass bottle of the greenish growths that he saw in the water. Leeuwenhoek had been experimenting with home-made single-lensed microscopes and had taken a close look at his lakewater samples. What he saw revolutionized the world of science, for he was astonished to see a myriad tiny microbes swimming about. In that instant, our modern era of bioscience was born. Yet (to quote cell biologist Nick Lane in a recent video for the Royal Society) scientists still do not know what Leeuwenhoek saw. After reading this article, they will.
Afterimage | The Eyes Have It!
Jim Dunlop — Kalamazoo County Sheriff's OfficeThe Microscope 71:2, p. 96, 2024
The multiple random orientations of recrystallization of an illicit methamphetamine sample from a syringe evokes notions of an African safari; original magnification is 100×, crossed polars. Selected as Best Overall Photomicrograph at the Inter/Micro 2024 Photomicrography Competition in Chicago.
The multiple random orientations of recrystallization of an illicit methamphetamine sample from a syringe evokes notions of an African safari; original magnification is 100×, crossed polars. Selected as Best Overall Photomicrograph at the Inter/Micro 2024 Photomicrography Competition in Chicago.
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