Abstracts, Last Names M-Z
Abstracts are listed alphabetically by the last name of the speaker. Abstracts and speakers are subject to change; check this page regularly for additions and updates.
Continuing Adventures in Fluorescence
Charles Mazel — NIGHTSEA
NIGHTSEA primarily develops equipment for viewing and documenting fluorescence, both off-the-shelf and custom, and in doing so we encounter diverse opportunities and challenges. Some of these do not even involve fluorescence. This talk will review some of our experiences in the past year: what we have learned, what we are working on, and even how Inter/Micro itself proved invaluable in one project.
Unwanted Connections — From Whiskers to Nanotubes
James R. Millette — Millette Technical Consulting
Electrically conductive particles, especially those with elongated morphologies, are an important concern in areas housing electronic equipment such as data centers. A number of catastrophic computer system failures have been attributed to zinc whiskers reported from zinc-plated floor materials. Metal turnings and wear debris from carbon fiber products can also provide the opportunity for unwanted connections (short circuits) between electrical components. Most recently, ultra-microscopic “fiber” nanotubes have caused concern about unwanted electrical connections on the smallest scale. Microscopy is the best tool to find these very small electrical connectors among the dust particles that inhabit electronic information storage systems. Elemental analysis from scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) is very useful for zinc and other elongated metal particles. Transmission electron microscopy coupled with EDS (TEM-EDS) is necessary for the investigation of nanotubes.
Glass Bottle Thickness Variation: Measurements for Source and Comparison Determination
Brendan Nytes, Ethan Groves, Rachel Rutter, Skip Palenik, and Christopher S. Palenik — Microtrace LLC
Forensic glass analyses are typically conducted as comparisons; however, the particles can also be analyzed for the purposes of placing constraints on a possible source (e.g., did a glass particle originate from a container or from a particular type of container?). Regardless of the source, thickness (of full thickness glass fragments) represents a useful property for comparison.
For sheet glass, a goal of production is consistency in thickness. For container glass, thickness is a more complicated variable that is more difficult to exploit. Consider, for example, a wine bottle. A causal observer would note that the neck is made of thinner glass than the upper rim (where the cork is inserted). The variation exists in most container glass. In addition, it is anticipated that the permitted tolerances in glass variation, at a given location on a particular container, are larger than in sheet glass. Knowledge of the variation in container glass for a particular class of container e.g., wine bottle, beer bottle, etc., has benefits for both sourcing and comparison. For sourcing purposes, the benefit is in knowing if a particular fragment is consistent with a particular type of container. For comparison purposes, knowledge of the variation in the thickness of a given source is important when attempting to compare a questioned fragment to a potential source.
Because the thickness of questioned fragments can be measured relatively easily by a variety of methods, e.g., calibers, under a microscope, using automated image analysis, the evaluation of thickness ranges in a container by this approach would be impractical. To that end, a novel (to forensic science) method of thickness measurement using an ultrasonic probe has been evaluated. This research provides the results of our method validation. The method was then used to produce detailed thickness maps of several different container types. These maps were used to determine the thickest and thinnest parts of each container type.
“The Particle Was Identified as a Cellulose Fiber”
Skip Palenik — Microtrace LLC
In our laboratory, we are frequently asked to identify fibrous particles. New microscopists at Microtrace learn early in their careers that merely identifying an unknown particle as a cellulosic fiber (not a cellulose fiber) usually results in a gross under estimation of the information that such a particle can provide about itself, its history, and its origin.
This presentation will explain and demonstrate some of the characteristics that cellulosic particles can be coaxed into revealing about themselves by the well-prepared observer who has been trained to appreciate the telltale features and attributes, many of which are not obvious even under the microscope, by someone trained to look for them and possessing that most important knowledge of what to look for.
Homemade Explosives: Not for Every Do-It-Yourselfer
William A. Randle — Missouri State Highway Patrol Crime Lab
Explosives cases submitted to the crime laboratory consist of many different manufactured explosive mixtures, as well as homemade explosive mixtures. However, not all homemade mixtures intended to be explosive are explosive. A review of a few cases from the Missouri State Highway Patrol Crime Lab highlight some homemade “explosive” mixtures that were real duds.
Fiber Survey of Selected Postage Stamps
Walter J. Rantanen — SGS-IPS Testing
Paper postage stamps have been used for well over a century. The fiber content of stamps has fluctuated depending on where they originated and as different fiber sources became available. This survey will examine the fiber content from the early 1900s to the present day. Stamps for examination were selected from letters, postcards, and purchased sets, along with some from a prized collection.
The Ever-Expanding World of Microscopy, Imaging, and Microanalysis
John A. Reffner — John Jay College, CUNY
Today, microscopy is being stimulated by the barrier of the diffraction limit of resolution being breached. The ability of scanning probes to reach nano-spatial resolution and the integration of microscopy with spectroscopy is a new technology. Confocal fluorescence microscopy and near-field optical scanning microscopy are capable of resolving molecular structure. Photo-thermal infrared spectroscopy has demonstrated sub-micrometer spatial resolution and high quality infrared absorbance spectra. Combining scanning probe with tunable laser technology or synchrotron radiation makes molecular vibrational spectra with nanometer scale spatial resolution possible.
The tentacles of microscopy extend to many disciplines and levels of complexity. The circus of life seen with a microscope in a drop of pond water has inspired many to pursue scientific careers. The hand lens gave us the means to explore the minutia of a fingerprint or discover the many minerals in rocks and sand. The pathologist’s diagnoses of diseases, by studying the microstructure tissue sections, play a vital role in public health. Metallurgists and material scientists use microscopy in many ways to improve materials or to determine why materials fail. Where will the new technologies take us? How will we become educated about these technologies and their application to real-world problems?
Improved Quantitative Assessment of Carbon Black Dispersion in Polyolefins by Light Microscopy
John R. Reffner and Day-Chyuan Lee — Dow Chemical Company
Carbon black dispersion in polyolefin-based compounds is often assessed using visible light microscopy, and standard test methods such as ASTM D5596-03, ISO 18533, and ISO 11346 have long been established for the quantification. These methods are based on visual assessments of a very limited sample area. In this talk, I will discuss some limitations of these test methods and present a procedure using stage automation/image collection and image analysis. Stage automation allows a large number of images to be collected without operator bias. Image analysis provides quantitative information on both sample thickness and the size of undispersed carbon black domains. The combination provides a rapid and more statistically significant assessment with significantly more sensitivity to low levels of poor dispersion.
Evaluation of the Canon Rebel T7i for Photomicrography
Sebastian Sparenga — McCrone Research Institute
Photographic documentation is a must for any microscopy lab. There are numerous microscope-dedicated camera options currently on the market, but many of the higher performance models that are touted as being better suited for difficult-to-photograph techniques like fluorescence, come at a hefty cost. Plus, they only function on a microscope and cannot be used for any other regular photography needs that the laboratory may have. This talk will discuss a consumer DSLR option for all types of photomicrography, including brightfield, darkfield, fluorescence, and polarized light microscopy techniques.
A Bone to Pick: Examination and Analysis of Bone Tissue
Katie M. White and Skip Palenik — Microtrace LLC
When a cadaver decomposes, bones are often all that remains from the body. They persist due to their hardness and durability, a result of their composite nature. When found as whole bones, their morphology can be very distinctive to pathologists or anthropologists. However, in our work as microanalysts, we often encounter them as fragments of an unknown material to be identified.
The cellular structure of bone results in a unique morphology. Microscopical examination of bone fragments permits recognition of these diagnostic structures. In addition to morphology, microchemical and microprobe analyses can provide information about the composition of suspected bone particles. The characteristics that are available for study may vary depending on the source and condition of the fragments themselves.
In addition to their significance in criminal forensic casework, identification of bone often plays an important role in other types of investigations. Bone is present in animal feeds and cremated remains and may be a component of decorative or historical artifacts. In food manufacturing, bone fragments may also appear in processed meat products, sometimes occurring as an undesirable byproduct.
This presentation will demonstrate the properties and microscopical features that are most valuable for the identification of bone tissue in the laboratory, and the preparation methods used in these analyses. Case examples involving bone fragments will also be presented.
How Low Can You Go? Determining the Smallest Steel Fragment for Quantitative Analysis
Peter D. Zoon — Netherlands Forensic Institute
At the Netherlands Forensic Institute (NFI) microtrace analysis of (metal) fragments embedded in bone is a routine part of examinations. These examinations are typically performed with scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS) analysis to determine the elemental composition of the fragments. Most of the encountered traces are (stainless) steel fragments. As previously discussed, obtaining reliable quantitative elemental compositions with SEM-EDS is not trivial under best of circumstances. To increase the evidentiary value of SEM-EDS analyses of small metal fragments embedded in bone, the quantitative elemental composition of small metal fragments was determined with laser ablation inductively coupled mass spectrometry (LA-ICPMS).
Small samples cut from knife blades showed promising results. These samples are however an order of magnitude larger than the traces typically encountered in bone. A method for generating small fragments without contamination was devised, and the small fragments were analyzed and the obtained compositions have been compared to the composition of the blades.
The smallest fragments that could be reliably analyzed are approximately 50 × 50 µm in diameter. The thickness of the fragments was not determined, but it seems reasonable that this should be approximately the same. This lower limit is not governed by the analytical measurement technique, but rather by the nature of the samples themselves.
To conclude this presentation, a case example will be presented in which the above-mentioned analysis was used to determine if metal fragment in the skull bone of a victim could originate from a knife handle.