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Abstracts, Last Names A-L

Abstracts are listed alphabetically by the last name of the speaker. View the presentations schedule.
Abstracts and speakers are subject to change; check this page regularly for additions and updates.

View Abstracts, Last Names M-Z


Morphology and Microanalysis of Aluminum Powders
JenaMarie Baldaino1, Jack Hietpas1,2, and JoAnn Buscaglia31FBI Laboratory, Counterterrorism and Forensic Science Research Unit, Visiting Scientist Program; 2Pennsylvania State Forensic Science Program; 3FBI Laboratory, Counterterrorism and Forensic Science Research Unit
Online sharing of YouTube videos and instructional manuals on how to construct improvised explosive devices (IEDs) inform amateur bomb makers of the easily accessible household materials that can be used to make aluminum (Al) powder. Previously, we discussed Al powders produced from ball-milling Al foil and extracted from spray paints containing Al flake. The results obtained from scanning electron microscope photomicrographs demonstrate that Al powder manufactured by ball milling could be confidently differentiated from those extracted from an Al flake-containing spray paint. Furthermore, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) analysis of the spray paints containing Al flake provided additional information that could differentiate between brands and among products within brands.

Additional methods to either obtain or extract Al powder include melting Al cans to form an Al ingot, then using a steel file to produce Al powder; grinding Al foil with a coffee grinder; binary exploding targets; and extracting Al powder from pyrotechnics such as sparklers and firecrackers. This presentation will discuss the differences in Al particle surface characteristics and elemental compositions of these additional sources using SEM-EDS.
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What Is This? The Peculiar Tale of a Food Contaminant
Jason C. Beckert — Microtrace, LLC
The vast majority of the food contaminants identified at our laboratory can be associated with the product itself, e.g., a clump of ingredients, charred product, etc.; related to the wear of processing equipment, e.g., fine metal particles, rubber, etc.; or they are recognizable objects that are relatively ubiquitous in everyday life, e.g., a staple, an insect, etc. Although each sample is unique, most contaminants can be classified into one of several “usual suspect” categories that are repeatedly encountered. This presentation will discuss a truly unique food contaminant submitted to our laboratory for identification. First impressions were deceiving, and consultation with our client indicated that the sample was even more unusual than we previously thought. The contaminant was found to be composed of numerous components, and it was clearly assembled by human hands. The rationale behind its construction remains a mystery, and the presenter hopes that the audience will be able to suggest a satisfying answer to this enigmatic case.
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The Forensic Analysis of 3-D Printer Dust Particles
Kelly Brinsko Beckert and Christopher S. Palenik — Microtrace, LLC
3-D printers are becoming increasingly efficient and economical and thus more widely accessible to the public. Previous research has documented the release of dust particles during the printing process, however, little is known about their morphology and other characteristic features. This study was undertaken as part of a federal research cooperative agreement (NIJ Award No. 2015-DN-BX-K033) to characterize these particles so that they may be collected, recognized, and analyzed appropriately. Samples were collected from a variety of 3-D printers, representing both consumer- and commercial-grade models. 3-D printers use thermoplastic filaments, typically polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS), although others may be used, including nylon, polyvinyl acetate, and polyurethane. Cotton or polyester-flocked swabs were used to collect dust from various surfaces within the printer chamber and from surrounding areas up to 10 feet away. Particles produced from ABS filaments are most easily recognized based on color and rounded morphology via light microscopy. Fourier transform-infrared (FT-IR) spectra of the particles confirmed the identification of the ABS polymer. Pigments and the ABS polymer matrix were also identified using Raman microspectroscopy. Dust from PLA printers consistently contained finer, submicron-sized particles (relative to background levels) that could be observed by field emission scanning electron microscopy (FEM); however, the size of the particles precluded their specific identification as PLA. This presentation will detail the collection procedures employed to find, isolate, identify, and compare 3-D printer dust particles and include a discussion of their potential applications and limitations as forensic evidence.
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Validating a Raman Microspectrometer in an ISO-Accredited Forensic Laboratory
Andrew M. Bowen — U.S. Postal Inspection Service
Raman microspectroscopy has a number of advantages over more traditional instrumentation used in forensic laboratories, including its excellent spatial resolution and confocal capabilities. These make it possible to definitively identify numerous particulate components in complex mixtures, non-destructively, with minimal sample quantity. This presentation will discuss the recent validation of a two-laser Raman microspectrometer in an ISO 17025-accredited forensic laboratory. The validation design and results obtained will be described, together with lessons learned during the process. Practical advice for scientists who plan on conducting future validation studies will be shared, along with issues of potential concern during general use of Raman microspectroscopy in a forensic laboratory.
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Forensic Drug Identification by GC/MS and PLM
Andrew M. Bowen — U.S. Postal Inspection Service
Gas chromatography/mass spectrometry (GC/MS) is often called the workhorse of the forensic drug laboratory. It is well suited for this purpose, providing two independent analytical results: retention time and mass fragmentation pattern. Like all instruments, GC/MS has limitations. Of primary concern for drug chemists are its inability to distinguish between some structural isomers and its inability to determine the salt form of identified compounds. Some laboratories accept these limitations and communicate any uncertainties in their reporting language. Other laboratories use additional instrumentation, commonly Fourier-transform infrared spectroscopy (FT-IR), to pursue more definitive identifications. The primary limitation of FT-IR is that spectra of mixtures can be challenging to interpret. Chemical extractions can sometimes separate the drug of interest from other compounds present, but this is not always possible. Polarized light microscopy (PLM) is capable of distinguishing different salt forms of compounds as well as different positional isomers, even when the controlled substance is a minor component in a mixture. Analysis by PLM takes only minutes and requires a minimal sample. This presentation will share examples from casework and training that illustrate how GC/MS results can be supplemented by PLM to provide additional specificity to the identification of controlled substances.
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Takata Airbag Death No. 10 — Investigation to Determine Projectile Source
Richard S. Brown — MVA Scientific Consultants
In December 2015, the driver of a 2006 Ford Ranger was found dead after colliding with an object in the road. The pickup truck’s airbag had deployed during the collision. A subsequent autopsy revealed an apparent gunshot wound in the driver’s neck. We were requested by the coroner’s office to determine the composition and source of the projectile slug. The suspected source of the slug was the driver’s side airbag module located in the steering wheel of the vehicle. Examination of the components of the airbag module revealed that the airbag inflator had ruptured from excessive pressure and that the initiator, inside of the airbag inflator, had fractured into two pieces. One of the pieces penetrated the driver’s neck; the other piece was found pressed onto the steering wheel mounting nut. The investigation was supplemented by examining an exemplar airbag inflator using 3-D computer tomography. The types of materials analyzed included labels on the inflator, adhesive, and fracture patterns. Fluorescence microscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), calipers, and a microchemical test for ammonium ions were used during the investigation. The airbag inflator was manufactured by the Takata Corporation and contained ammonium nitrate, which is at the center of the largest recall in automotive history.
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A History of Ammonium Nitrate Disasters; Why is Ammonium Nitrate in My Car’s Airbag Inflator?
Richard S. Brown — MVA Scientific Consultants
The storage and transportation of ammonium nitrate has resulted in some of the most horrific and deadly explosions in the last 100 years. The storage and use of ammonium nitrate as an explosive and as a fertilizer remains widespread. Examples of past disasters include but are not limited to:

• April 2, 1916 – “The Great Explosion,” Faversham, Kent, England, 115 dead
• July 26, 1921 – Kriewald, Germany, 19 dead
• Sept. 21, 1921 – BASF Oppau, Germany, 561 dead
• April 29, 1942 – Tessenderlo, Belgium, 189 dead
• April 16, 1947 – Texas City, SS Grandcamp, several hundred dead (all but one member of the fire department died)
• July, 28 1947 – Brest, France, 29 dead
• April 17, 2013 – West Texas, 15 dead

As a result of these “accidents” and subsequent investigations, the processing and storage of ammonium nitrate has changed. How ammonium nitrate reacts in the presence of variable temperature and humidity remains somewhat of a mystery. A summary of past research and incidents serves as a reminder of the explosivity and unpredictability of ammonium nitrate. So why is it in my car’s airbag?
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Observations on Temperature Variations in Liquid Mounts During Light Microscopical Investigations
Jan Burmeister
The precise measurement of the refractive indices of transparent small particles in an immersion liquid mount, using classical light microscopy and polarized light microscopy techniques, requires exact knowledge of the mount temperature, and that the necessary temperature coefficient calculation be applied to the liquid before stating final measurement results. Commercially available refractive index standards for microscopy are supplied as liquids in bottles with the temperature coefficient printed on the label.

Previous proposals for temperature measurement in a microscope’s light path, as published in handbooks and online articles, may be misleading due to the large and thermally inert mass of the mercury-containing thermometer bulbs that are routinely used today.

An experimental setup was devised and duly calibrated using a miniature NTC thermistor as the temperature sensor and a high-resolution ohmmeter to observe temperature effects in a way that is much closer to reality than in older, obsolete procedures.

The results for this particular setup show that only negligible thermal effects are observed in mounts containing three drops of immersion liquid. Extrapolation calculations for situations with less liquid in the mount show that, in such cases, the expectable temperature effects are also small to negligible.
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ISO 22262: The International Standard for Determination of Asbestos in Bulk Materials
Eric J. Chatfield — Chatfield Technical Consulting Limited
The proposal to develop an ISO standard method for determination of asbestos in bulk materials was initially discussed by the ISO/TC 146/SC 3/WG1 Working Group in 1998. ISO 22262 is the method that was developed over 18 years by the working group of international members. ISO 22262 was published in three parts: ISO 22262-1, “Sampling and qualitative determination of asbestos in commercial bulk materials” in 2012; ISO 22262-2, “Quantitative determination of asbestos by gravimetric and microscopical methods” in 2014; and ISO 22262-3, “Quantitative determination of asbestos by X-ray diffraction method” in 2016.

The purpose of ISO 22262 is to determine the asbestos content of a bulk material with sufficient accuracy to compare analytical results with various definitions of a regulated asbestos-containing material (ACM) used by different jurisdictions. These definitions are “any asbestos,” “greater than 0.1% asbestos,” “greater than 0.5% asbestos,” and “greater than 1% asbestos.” It was recognized that the level of analytical effort required to achieve this objective is variable depending on the regulatory definition, the nature of the material, and the asbestos concentration.

Many commercial building materials, particularly materials, such as sprayed fireproofing, pipe insulation, and asbestos-cement products, contain either a significant proportion of asbestos or no asbestos at all. For these materials, a polarized light microscopy (PLM) examination of the untreated material can often allow confident classification of the asbestos concentration with respect to its regulatory status with only a few minutes of observation. Other types of material present difficulties in both identification and quantification of asbestos. Transmission electron microscopy (TEM) or scanning electron microscopy (SEM) are specified in ISO 22262 as alternative methods for identifying asbestos, when results from PLM examination are ambiguous. When the asbestos concentration is estimated by PLM examination to be lower than approximately 5%, ISO 22262 specifies the use of gravimetric matrix reduction to improve the precision. ISO 22262 provides a tabulation of different materials, with recommended analytical procedures for each type.
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A Forensic Microscopy Approach to Identifying Particulate Matter Observed in a Sterile Ophthalmic Solution on Stability
Mary Lee Ciolkowski — Pharma Technical Services, Bausch & Lomb, a division of Valeant Pharmaceuticals
This presentation will describe a microscopical investigative approach to characterize particles that were observed during stressed stability testing of an ophthalmic solution formulation. Topical ophthalmic solutions should be “essentially free” of visible particulates upon inspection, as specified in the U.S. Pharmacopeia (USP). Ophthalmic solutions are also required to meet subvisible particulate matter requirements per USP Chapters <789/788> at the time of product release and during stability testing to verify manufacturing cleanliness and support shelf life of the finished product. The analytical characterization work needed in cases where USP <788/789> failures occur is considered trace or ultra-trace analysis. For example, the USP <789> limit for particles 10 – 25 µm is 50 particles/mL. If this limit is exceeded due to a needle-shaped particulate with a density of 1.5 g/cm3, this would correspond to ~8 ppb on a concentration basis for a 5 mL product fill size. Particle isolation and enrichment practices coupled with direct sample analysis using microanalytical techniques are essential to productive problem solving during particulate matter failure investigations, due to the inherent trace concentration levels. A progressive problem-solving approach based on forensic microscopy was utilized to isolate and characterize particulate matter in the ophthalmic formulation and identify its potential source.
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Torture Test: Microscopic Changes in Markings Made by a Tavor Rifle
Peter Diaczuk — Pennsylvania State University
Andrew J. Winter — Centenary University, NJ
The authors were given the opportunity to perform a “torture test” on a new rifle designed by Israeli Weapon Industries (IWI) called the Tavor. We fired just over 2,000 rounds of ammunition through the test rifle in a variety of weather conditions. Comparison microscopy of collected samples of cases and bullets was performed at 200-round intervals to determine whether microscopic changes occurred over time, influencing the ability to determine common origin.
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Possible Degradation Mechanisms of Antemortem Hair Roots Containing Induced PMRB-Like Features
Barbara L. Fallon, M.S. 1; Jack Hietpas, Ph.D.1,2; and JoAnn Buscaglia, Ph.D.11Federal Bureau of Investigation Laboratory, Counterterrorism and Forensic Science Research Unit; 2Pennsylvania State University Department of Biochemistry and Molecular Biology
A postmortem root band (PMRB) is a microscopic feature resulting from degradation to the pre-keratinized region of the roots of anagen hairs obtained from cadavers. A PMRB forms due to degradation of the intermacrofibrillar matrix (IMM) (or cell membrane structures) in the cortex resulting in elongated, gas-filled voids3. Hypothesized mechanisms for in vitro band formation include ammonium ions or evolved ammonia gas that may chemically attack the IMM; a change in hair pH that may lead to IMM degradation or collapse; or decomposition gases that may become trapped inside the cortex, thus mechanically disrupting the integrity of the root.

This work investigated these possible mechanisms of the IMM damage in the formation of PMRBs. PMRB-like bands were induced in intact hairs submerged in water, ammonium acetate, and pH 7.8 buffer. Microtomed hair slices exposed to the same solutions displayed mixed results. When observed, ultrastructural features of the induced PMRB-like bands were consistent with true PMRBs. These results may suggest a combined mechanism whereby chemical attack weakens the IMM and facilitates mechanical damage to form PMRBs.
3Hietpas, J.; Buscaglia, J.; Richard, A.H.; Shaw, S.; Castillo, H.; and Donfack, J. “Microscopical Characterization of Known Postmortem Root Bands Using Light and Scanning Electron Microscopy,” Forensic Science International, 267, pp 7 – 15, 2016.
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Imaginary Microorganisms and Impossible Worlds
Brian J. Ford — Caius College, University of Cambridge, U.K.
Reference books contain unrecognizable portrayals of microscopic organisms, and many earlier encyclopedias pay little attention to the accuracy of their accounts. How does this relate to the medieval imaginings of philosophers? And is modern science always better than the scribes from 500 years ago? Just as unicorns were ridiculous inventions, some present-day images are unreal, and they reveal how little science has progressed.
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Microbe Power in a Prehistoric Pizza
Brian J. Ford — Caius College, University of Cambridge, U.K.
Harnessing the energies of microbes as a means of survival was one of the earliest achievements of prehistoric humans. Circular flatbreads have been produced since ancient times, and the fermented ingredients of the modern pizza are examples of how the traditions of the Stone Age remain with us today. Much of the food we eat is processed, though the role of bacteria and mold in food production is widely ignored. Today, we will review some surprising examples.
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Examples of Expert vs. Expert Civil Litigation Errors in Dealing with the Purported Asbestos Content of Talc
Mickey Gunter — Geological Sciences, University of Idaho, Moscow
Matthew S. Sanchez — RJ Lee Group
Over the past few years, we have served as expert witnesses or as consultants for the defense, in several talc-related civil cases, mainly dealing with purported asbestos content of talc; our backgrounds are in geology, and especially mineralogy. As such, we have reviewed plaintiff expert reports as well as deposition and trial testimony. We have noted errors that often go uncontested, based on how the litigation evolves. In this presentation (and with follow-up publications) we will show examples taken directly from plaintiff expert reports and testimony that are factually incorrect and can easily be shown to be so based on established geological and mineralogical principals, as well as the peer-reviewed literature. Examples will include 1) incorrect location of deposits, 2) incorrect citations of peer-reviewed literature, 3) misuse of basic geological and mineralogical terminology, and most importantly, 4) misidentification of minerals. To be clear, we will make no challenges to expert opinions, just point out factual errors. As noted above, we have both served as paid expert witnesses for the defense, but they are providing no funds for the preparation of this abstract.
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Look-Alikes Type 1: Objects Within an Order of Magnitude of Size
Andrew A. Havics — pH2, LLC
Harry Alden — Alden Identification Service
Microscopists often encounter objects with the microscope that look like other objects. These look-alikes, or microscopic doppelgangers, come in a few types, the first being objects of similar size within an order of magnitude. Some of these look-alikes may be similar objects within a group or something completely outside that grouping. A few examples are fibers that have similar morphology or optical properties of asbestos, fungal spores with similar shape, similar amoebae, similar wood samples, other particles that look like fungal spores, spherical objects of various kinds, crystals with similar growth habits (snow and camphor), tobermite in cement and leaf surfaces, natural and synthetic fibers, clays and ferrous oxides, gunshot residue (GSR) and pyrotechnics, polymer whiskers, and fungal hyphae, etc.
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Contrast in Reflected Light Microscopy
Andrew A. Havics — pH2, LLC
Detection and resolution of objects in microscopy rely heavily on contrast. In 2011, the author presented a series of contrast techniques almost exclusively for transmitted light microscopy. There are comparably contrast techniques for reflected light microscopy as well. These methods include darkfield (DF), reflected Rheinberg illumination, Rheinberg sandwich-style illumination, polarized light microscopy (PLM), sensitive tint addition, Nomarski Differential Interference Contrast (DIC), staining of specimens, etching (thermal, selective dissolution, interference film, decorative), phase contrast microscopy (PCM), fluorescence, reflection contrast microscopy (RCM), metallization, fringe-based (monochromatic DIC and interference), and color filtration.
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Application of Rietveld Refinement to Forensic Samples
Joseph Insana and Christopher S. Palenik — Microtrace, LLC
Soil is analyzed and examined in a variety of ways for a multitude of reasons. Powder X-ray diffraction is used to identify different mineral phases found within a soil sample. Interpretation of these diffraction patterns in terms of phases present and the amount of each phase can be achieved using a technique known as Rietveld refinement. This is done by fitting a synthetic pattern to the sample pattern through an iterative process. The pattern fitting process as a whole takes into account instrumental variables that affect the pattern, as well as sample properties that include major and minor phases, amorphous contributions, the crystal structure, strain, and texture. When variables are properly constrained, the resulting output can provide an accurate quantitative analysis, which can be evaluated in light of the fit quality compared to the experimental results. By using this approach, Rietveld refinement may provide an alternative approach to forensic soil analysis, providing quantitative results that can be objectively evaluated in terms of quality and uncertainty. This presentation will illustrate the basic principles of Rietveld refinement and its application to a range of synthetic samples, including a blind, unknown sample.
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Thermal Recombination of Clay Mineral Components of Ancient Mayan Ceramic Ware as a Means of Differentiating Indigenous Versus Tradeware Using X-ray Diffraction Analysis
Wayne C. Isphording — Tulane University, Department of Continuing Education
Archaeologists have long been aware that valuable information on material exchanges among ancient civilizations can be obtained by identifying the mineral constituents in fragments of ceramic ware. In many cases, the minerals present are useful in determining whether a particular fragment is indigenous to the area where found or whether it represents tradeware from other locations. Even where inscribed design work allows positive source identification, the mineral content can still be used to further confirm this fact and indicate the extent of trade that existed at various ceremonial sites or population centers.

Ceramic materials used by ancient artisans for figurines, urns, pottery, etc. were classically manufactured by firing a mixture of clay and crushed fragments, known as “temper,” to temperatures of 300° C or higher in kilns. Clay components, lacking the addition of temper, were known to shrink and crack during drying or firing, rendering the products unusable. To avoid this, various forms of temper (crushed rock, charcoal, wood ash, etc.) were added to the clay to provide stability and strength. While most temper materials can be identified by polarized light microscopy, clays (which typically comprise the bulk of the objects) lose their identity once they are fired and can no longer be identified. This is unfortunate because the clay mineral component is often distinctive for specific geographic locations. However, a procedure does exist that can “recover” the identity of the original clay. This is done by firing pulverized shards (fragments) of the ceramic ware to temperatures in excess of 1100° C and then quickly quenching the sample. Heating the crushed ceramic powders at high temperature for at least 2 hours allows time for the constituent ions present to recombine and form new, high temperature phases (mullite, enstatite, spinel, cristobalite, etc.). These new phases can be confirmed by X-ray diffraction (XRD) analysis and serve as “fingerprints” for the original clay mineral. Using information from this procedure, it was quickly possible to differentiate indigenous pottery and figurine fragments found in the Guatemalan highlands and further south in Honduras from tradeware manufactured elsewhere in the northern Yucatan Peninsula.
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Microcrystal Tests for the Detection of Butylone, Methylone, and Ethylone
Shan Mei Jones — University of Illinois at Chicago Graduate Program, in association with McCrone Research Institute
Synthetic cathinones, commonly known as “bath salts,” have become more abundant on the U.S. drug market. These drugs are classified as stimulants and, therefore, have similar pharmacological effects as amphetamines. While butylone and methylone are both Schedule I drugs in the U.S., ethylone has yet to be scheduled. Microcrystal tests for these three drugs were researched and developed because it is difficult to identify synthetic cathinones by the usual forensic methods. Two common microcrystal test reagents — picric acid and picrolonic acid — form unique rosettes identifiable with each drug. Butylone and methylone form rosettes with picrolinic acid, while ethylone and methylone form rosettes with picric acid. All crystals were then analyzed using polarized light microscopy (PLM) and attenuated total reflectance (ATR) infrared microspectroscopy.
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The Effect of Ultraviolet Radiation on the Microspectrophotometry (MSP) of Dyed Fibers — Phase 1
Meggan B. King — McCrone Research Institute
This talk will discuss the initial applied research project design to study changes in dyed man-made fibers that result as an effect of environmental conditions, especially exposure to natural and artificial ultraviolet (UV) radiation over long periods of time. The McCrone Research Institute in Chicago has received funding from the National Institute of Justice (NIJ) under the FY 2016 Research and Development in Forensic Science for Criminal Justice Purposes (Award No. NIJ-2016-DN-0145) to provide a practical application of microspectrophotometry (MSP) as a tool for understanding how ultraviolet radiation can affect the color and dyes of fiber evidence and improve the discrimination, identification, and individualization of man-made polymer fiber products for the forensic scientist.
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The Trotter Collection: Microscopical Analysis of Human Scalp Hairs for 21st Century Research Questions
Sandra Koch, Nina G. Jablonski, and Mark D. Shriver — Pennsylvania State University, Department of Anthropology
Mildred Trotter, an anatomist and physical anthropologist at Washington University in St. Louis, conducted much of the early quantitative research on human hair form from the late 1920s to the mid-1950s. Her work greatly influenced our understanding of variation in the cross-sectional shape and diameter of scalp hair in a wide variety of human populations. Hair samples from her original studies, housed at the Smithsonian Institution, were used in this study. Sampling from this collection was undertaken in an effort to update her analyses with high-resolution microscopy and modern image-analysis software. The use of these techniques makes possible more detailed descriptions of morphological diversity in scalp hair forms within and among populations and the addition of novel discriminating morphological characteristics, which can inform human hair research.

For this project, hairs were sampled from 27 population groups represented in the collection. The hair samples were sectioned and then imaged using oil immersion light microscopy. Maximum and minimum diameters were measured to calculate the degree of ellipticity and for comparison with the hair index and area calculations recorded in Trotter’s notebooks and publications. Further analysis was conducted using the particle analysis function within the ImageJ image-processing program to assess the number, distribution, and relative density of melanosomes present within a hair cross section. The goal of this research work is to explore correlations between patterns of microscopical and genetic variation, and provide quantitative data for further research.
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Using SEM-EDS for Quantitative Forensic Glass Comparisons: Some Things to Think About
Thomas A. Kubic — John Jay College and The Graduate Center, CUNY; Thomas A. Kubic and Associates
Alex Comanescu and Tiffany Millet — The Graduate Center, CUNY

Energy-dispersive X-ray spectroscopy (EDS), especially employing a scanning electron microscope (SEM) for an excitation source, is a core elemental characterization technique for micro and ultra-micro size samples. This technique has long been used for adding evidential value to the microscopical forensic examination of transfer evidence. Glass chips are one specific class of transfer evidence for which this technique has been employed. In this talk, we will present the results of follow-up work on 46 glass samples for which visible microspectrophotometric results were previously reported.

As a strategy for comparing glass samples by SEM-EDS, criminalists often normalize the data and compare ratios of peak heights or areas to one common major element such as silicon. Courts today often require data about the frequency of occurrence of similar spectra to assist the trier of facts about the weight of this comparative evidence. One of the goals of this project was to provide insight into this matter.

Being mindful of a caveat by Dr. Peter Zoon of the Netherlands Forensic Institute to be careful about how we generate and use data obtained with computerized black-box software, we evaluated the quantitative data generated from the blue glass samples and a pair of standards from the National Bureau of Standards (now National Institute of Standards and Technology [NIST]), with commercial software utilizing both their standardless and standard algorithms. In addition, we processed the raw data using NIST’s Desktop Spectrum Analyzer II (DTSA II), a software tool for quantifying EDS spectra. We will present the results of these investigations.
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View Abstracts, Last Names M-Z