The Microscope – Volume 68, Third/Fourth Quarters 2020
IN THIS DOUBLE ISSUE
On the cover
A highly altered and degraded Dimetrodon bone; epi-illumination combined with ≈ 30% transmitted light. See Optical Method for Characterizing Opaque Regions of a Fossil Thin Section, page 132. (Photomicrograph courtesy of James Solliday)
Editorial | Doubling Down After a Rough Patch
Gary J. LaughlinThe Microscope 68:3/4, p. ii, 2020https://doi.org/10.59082/UYPQ7418
Excerpt: We are happy to present this latest edition of The Microscope as a full 96-page double issue, Volume 68, Third/Fourth Quarter 2020. It was an absolute necessity to combine two issues, as all of our operations — educational, research, symposia, and publications — were either canceled, postponed, or suspended for the first half of 2021 and the prior year due to the Covid-19 pandemic. To say this has been a rough patch for all would be an understatement, though I am glad we are here to write about it, while looking ahead to a favorable future.
A Comprehensive Suite of d-θ Look-Up Tables for Indexing Zone-Axis SAED Patterns of Amphibole Asbestos and Related Minerals
Shu-Chun Su
The Microscope 68:3/4, pp. 99–110, 2020https://doi.org/10.59082/KWJG3224
Abstract: The analysis of asbestos minerals below optical resolution is conducted by the analytical transmission electron microscopy (TEM). The Asbestos Hazard Emergency Response Act (AHERA) protocol mandates the measurement of three properties: the morphology by the TEM imaging, the elemental composition by the energy-dispersive X-ray spectroscopy (EDS), and the crystal structure by the zone-axis selected area electron diffraction (SAED). After the acquisition of a zone-axis SAED pattern with EDS-derived mineral identity, the practical and effective methodology of its indexing and interpretation is the comparison of the measured (observed) values of the d-spacings of two intersecting direct lattice planes and their interplanal angle against the reference values in pre-calculated d-spacing and interplanal angle look-up tables (d-θ table) based on the mineral’s unit cell parameters and symmetry. This paper presents a suite of hitherto most comprehensive d-θ look-up tables (more than 800 pages and 36,000 zone axes) for five regulated amphiboles (anthophyllite, grunerite, riebeckite, tremolite, and actinolite), three non-regulated ones (winchite, richterite, and cummingtonite), and talc, which could be confused with the regulated anthophyllite to facilitate the analysis of zone-axis SAED patterns. The procedure of using the d-θ look-up table is illustrated by two examples. Issues relevant to applications of d-θ table are also discussed. Click on the following mineral names to access the d-θ look-up table (PDF file) for anthophyllite, grunerite, riebeckite, tremolite, actinolite, winchite, richterite, cummingtonite, and talc.
Abstract: The analysis of asbestos minerals below optical resolution is conducted by the analytical transmission electron microscopy (TEM). The Asbestos Hazard Emergency Response Act (AHERA) protocol mandates the measurement of three properties: the morphology by the TEM imaging, the elemental composition by the energy-dispersive X-ray spectroscopy (EDS), and the crystal structure by the zone-axis selected area electron diffraction (SAED). After the acquisition of a zone-axis SAED pattern with EDS-derived mineral identity, the practical and effective methodology of its indexing and interpretation is the comparison of the measured (observed) values of the d-spacings of two intersecting direct lattice planes and their interplanal angle against the reference values in pre-calculated d-spacing and interplanal angle look-up tables (d-θ table) based on the mineral’s unit cell parameters and symmetry. This paper presents a suite of hitherto most comprehensive d-θ look-up tables (more than 800 pages and 36,000 zone axes) for five regulated amphiboles (anthophyllite, grunerite, riebeckite, tremolite, and actinolite), three non-regulated ones (winchite, richterite, and cummingtonite), and talc, which could be confused with the regulated anthophyllite to facilitate the analysis of zone-axis SAED patterns. The procedure of using the d-θ look-up table is illustrated by two examples. Issues relevant to applications of d-θ table are also discussed. Click on the following mineral names to access the d-θ look-up table (PDF file) for anthophyllite, grunerite, riebeckite, tremolite, actinolite, winchite, richterite, cummingtonite, and talc.
Microscopy in the Investigation of Asbestos-Containing Friction Products
James R. Millette, Steven Compton, and Christopher DePasqualeThe Microscope 68:3/4, pp. 111–131, 2020
https://doi.org/10.59082/ORSI3069
Abstract: Bulk analyses of approximately 100 asbestos-containing friction products showed levels of chrysotile ranging generally from 15% to 60% by volume. Small amounts of amphibole asbestos (primarily tremolite) were found in over 95% of the brake and clutch productstested. The amphibole asbestos was present in the range of 0.0001 to 0.4% by weight. Although the levels of amphibole asbestos were less than 1% by weight, the concentration of amphibole fibers was in the millions fibers per gram of friction material in many cases. The results of 11 studies of asbestos fiber release from brake materials, conducted by MVA Scientific Consultants (MVA), involved various activities such as sanding, filing, grinding, rivet removal, drilling, sweeping, compressed-air blowing, brake removal, and handling of contaminated clothing are presented. Following acid/base digestion, amphibole asbestos fibers were found in air samples in two of the studies. An analysis of brake wear dust found chrysotile asbestos fibers but no forsterite.
Abstract: Bulk analyses of approximately 100 asbestos-containing friction products showed levels of chrysotile ranging generally from 15% to 60% by volume. Small amounts of amphibole asbestos (primarily tremolite) were found in over 95% of the brake and clutch productstested. The amphibole asbestos was present in the range of 0.0001 to 0.4% by weight. Although the levels of amphibole asbestos were less than 1% by weight, the concentration of amphibole fibers was in the millions fibers per gram of friction material in many cases. The results of 11 studies of asbestos fiber release from brake materials, conducted by MVA Scientific Consultants (MVA), involved various activities such as sanding, filing, grinding, rivet removal, drilling, sweeping, compressed-air blowing, brake removal, and handling of contaminated clothing are presented. Following acid/base digestion, amphibole asbestos fibers were found in air samples in two of the studies. An analysis of brake wear dust found chrysotile asbestos fibers but no forsterite.
Optical Method for Characterizing Opaque Regions of a Fossil Thin Section
James SollidayThe Microscope 68:3/4, pp. 132–138, 2020https://doi.org/10.59082/MSET6356
Abstract: Transmitted light microscopy, with brightfield, polarized and crossed-polarized methods of illumination, are often employed in the histological and morphological interpretation of fossil thin sections. These methods are quite sufficient for the carbonate-based regions of the section; however, iron-based areas are often completely opaque and block all transmitted light. In order to study and characterize this opaque region it is necessary to reverse the angle of illumination to expose the top surface of the obscured areas. This technique has rarely been applied to the analysis of fossil thin sections and thus justifies this study in order to determine if the method can be of value. Epi-illumination, which creates brightfield and darkfield epi-illumination, was found to characterize areas of the section that are obscured to standard light microscopy. In most cases, opaque areas respond with high reflectivity providing clues to its density and composition. Standard thin-section methods are sufficient as long as the exposed surface is polished and preferably no coverslip is applied. The specimen in this study is a thin section of a fossil, 50 μm thick, from the scapula of a Dimetrodon sp. from the Lower Permian period.
Critical Focus | Forgotten Women Who Lit the Way
Brian J. Ford
The Microscope 68:3/4, pp. 139–150, 2020https://doi.org/10.59082/NNCU1575
Excerpt: Curiously, I was one of the first people ever to see a coronavirus. It was only because of a brilliant young woman that anybody saw it at all. She had been a promising science pupil at school in Glasgow, but her father was a bus driver and nobody they knew had ever gone to university. So in 1947, the young June Hart left school at 16 and trained as a histopathology technician at Glasgow Royal Infirmary, routinely preparing hematoxylin and eosin-stained sections for oil-immersion microscopy. She married a Venezuelan artist named Enrique Rosalio Almeida and moved to London, and from there they went to Canada, where she became the first electron microscopist at the Ontario Cancer Institute. She had no formal academic qualifications yet was awarded a Sc.D. degree on the basis of her remarkable publications. She was later recruited to work on viruses by St. Thomas’s Medical School in London — the same hospital that was to treat Prime Minister Boris Johnson when he contracted Covid-19 in April 2020.
Measuring Volume and Surface Area
John C. Russ
The Microscope 68:3/4, pp. 151–155, 2020https://doi.org/10.59082/SCDE1405
Abstract: High quality computer-gene rated visualizations of 3-D datasets obtained with a variety of microscopies are used in many different fields of application. It seems natural to attempt to perform measurements of the volume within or under a surface, and the area of that surface, as these values can be related to various properties of the subjects. There are concerns, however, with the methods that may be applied to perform the measurements, and it is instructive to examine the consequences of the procedures applied to the raw image data to generate the surface renderings and/or to estimate the 3-D measurements. The effects of these procedures on volumes are relatively modest, but surface areas are highly dependent on the resolution of the original data and the processing and measurement operations, and the results are generally unreliable.
New Microcrystal Tests for Controlled Drugs, Diverted Pharmaceuticals, and Bath Salts (Synthetic Cathinones): MDPV and 4-MEC
Sebastian B. Sparenga, Gary J. Laughlin, Meggan B. King, and Dean GolemisThe Microscope 68:3/4, pp. 156–171, 2020https://doi.org/10.59082/SNVG6351
The Microscope is publishing selected monographs from McCrone Research Institute’s recently completed research, New Microcrystal Tests for Controlled Drugs, Diverted Pharmaceuticals, and Bath Salts (Synthetic Cathinones), which contains newly developed microcrystaltests and reagents with 9 additional drugs: alprazolam, butylone, mephedrone, methylone, MDPV, 4-MEC, alpha-PVP, tramadol, and zolpidem. This issue includes the monographs for the following drugs/reagents:
• MDPV/palladium chloride with hydrochloric acid and phosphoric acid• MDPV/gold bromide with phosphoric acid and acetic acid• 4-MEC/palladium chloride with hydrochloric acid and phosphoric acid• 4-MEC/gold chloride with sulfuric acid
Microscope Past: 30 Years Ago | Fusion Methods Identification of Inorganic Explosives
John H. Kilbourn and Walter C. McCrone
The Microscope 68:3/4, pp. 172–179, 2020
Letters to the Editor | Leeuwenhoek Microscopes and “Nonscience”
The EditorsThe Microscope 68:3/4, pp. 180–187, 2020https://doi.org/10.59082/PYZN2235
The following letters were submitted by readers responding to a recently published article by Brian J. Ford for his viewpoint column, Critical Focus: Science, What Science? (68:1, pp 33–45, 2020). The Microscope encourages reader feedback, and we prefer to publish letters to the editor that are fewer than 500 words. However, in this instance, where they exceed this limit, we are publishing them in their entirety with the intent to present clearly all of the views of the author and respondents.
Author and Subject Indexes: Volume 68, 2020
The Microscope 68:3/4, pp. 188 - 191, 2020
Afterimage | Victorian Diatom Art
From a vintage slide collection of the State Microscopical Society of Illinois (SMSI); plane polarizedlight. (Photomicrograph by Meggan King and Sebastian Sparenga, McCrone Research Institute)
Copyright © 2020 Microscope Publications, Division of McCrone Research Institute. All rights reserved.