Social and Behavioral Sciences Commons^™

Creation And Optimization Of An Optical Trapping Microfluidic Device For The Separation Of Mock Forensic Sexual Assault Samples, Mackenzie Lally

Master of Science in Forensic Science Directed Research Projects

Cell mixtures are often seen in forensic samples and commonly involve sexual assault cases where mixtures of sperm cells and vaginal epithelial cells are frequently encountered. This produces challenges in downstream analysis in the form of STR mixture profiles. The only method currently in use in crime laboratories for front-end sperm and epithelial cell separation is differential extraction. This method often results in STR mixture profiles due to carryover into both the male and female fractions and suffers from a wide range of efficiency depending on the laboratory or individual processing the sample. Optical trapping offers an alternative method for …

Evaluation Of Cell Lysis Techniques For Direct Amplification Of Sexual Assault Samples, Sarah Schellhammer

Master of Science in Forensic Science Directed Research Projects

Sexual assault is one of the most common crimes committed today with a delay in sample processing, resulting in the “rape kit backlog”. The traditional method to extract DNA from these samples containing both male and female DNA is a differential extraction; taking hours to process. This study examined a variety of different cell lysis techniques to develop a method which can consistently generate high-quality profiles at a fast rate and with low volumes when compared to the currently used method in our laboratory.

Six lysis methods, in addition to the currently used forensicGEM™ Sperm kit, were performed on …

Testing The Efficacy Of Surface Swab Sampling To Determine Post-Mortem Submersion Interval (Pmsi), Using The Microbiome Colonization Of Skeletal Remains Submerged In A Lotic Environment, Sarah Rose

Master of Science in Forensic Science Directed Research Projects

Estimating the post-mortem submersion interval (PMSI) can provide a valuable forensic tool for medicolegal death investigations involving victims discovered in aquatic environments. Previous studies conducted by Cartozzo et al. (2021) successfully demonstrated the use of microbial succession to create predictive models for the estimation of PMSI from submerged bone. Though effective, bone sampling requires time consuming processing techniques that result in destruction of decedent tissue. This study investigates the use of bone surface swabbing as an effective alternative method to bone sampling, with the goal of predicting PMSI using a simpler, non-invasive sampling technique. Porcine (Sus scrofa) skeletal remains (rib …

Comparison Of The Bacterial Community Structure Of Bone Swabs To Ground Bone Recovered From Waterlogged Skeletal Remains From A Lentic Environment For Postmortem Submersion Interval (Pmsi) Estimation, Hannah Johnson

Master of Science in Forensic Science Directed Research Projects

Postmortem submersion interval (PMSI) is an essential factor when recovering bodies from aquatic environments. Although several studies exist on postmortem interval (PMI) estimation of mammalian cadavers in terrestrial systems, the same is not true for the aquatic systems. Cartozzo et al. (11) developed PMSI prediction models using bacterial succession data associated with waterlogged skeletal remains. This study is a continuation of the Cartozzo et al. (11) study, but the aim of this study is to compare the bacterial DNA (16S rDNA) community found on the surface of swabs recovered from waterlogged bones to the bacterial DNA obtained from ground bone …

The Efficacy Of Recovering Latent Fingerprints From Fired Cartridge Cases By Way Of Cyanoacrylate Fuming Combined With Basic Yellow Dye Staining, Lily Mantz

Master of Science in Forensic Science Directed Research Projects

This experiment attempted to tackle the long-standing struggle to consistently recover latent fingerprints from fired cartridges. With an emphasis on realistic handling of high volume of samples combined with Cyanoacrylate fuming followed by Basic Yellow dye staining, a total of 740 cartridges were examined. These included fired and unfired brass and nickel case 9mm Luger and 40 S&W cartridges. The cartridges were divided into five different groups; each were treated differently prior to cyanoacrylate fuming and dye staining, which was conducted in the same manner for the groups. The groups included the positive and negative controls, loaded, cycled, and fired. …

Evaluation Of Dna Extraction Efficiencies Of Promega’S Dna Iq™ Methods And Casework Extraction Kit For Low Template Samples, Emily M. Anderson

Master of Science in Forensic Science Directed Research Projects

Biological evidence from crime scene samples frequently contain low levels of DNA, such as the most predominant form of evidence, which is DNA deposited by handling objects or “touch evidence”. To maximize the DNA yield recovered from theses challenging samples, forensic laboratories must optimize the extraction methods utilized to isolate and purify DNA for downstream short tandem repeat (STR) amplifications. Currently, the Virginia Department of Forensic Science (VADFS) uses a DNA IQ™ System (DNA IQ) extraction method for isolation of DNA from most forensic samples. This extraction procedure, which combines DNA IQ™ lysis buffer and Dithiothreitol (DTT), has been validated …

Validation Of The 4-Aminophenol Chemical Test And Analytical Testing Scheme To Distinguish Marijuana And Hemp, Kenna Lewis

Master of Science in Forensic Science Directed Research Projects

With the passing of the 2018 Farm Bill, which legalized hemp, law enforcement agencies and forensic laboratories needed a more efficient testing scheme to differentiate marijuana and hemp Cannabis plants. The validation of the 4-aminophenol chemical test and the subsequent analytical scheme allows for this differentiation to be performed. The evaluation of eighteen different cannabinoids, including acids, demonstrated that compounds with structures similar to tetrahydrocannabinol (THC) produced a blue result and compounds with structures similar to cannabidiol (CBD) produced a pink result. Several titration curves with varying concentrations of cannabinoids indicated a pink result when the THC concentration was less …

Analysis Of Pellet Patterns And Gsr Produced From Judge Taurus Revolvers, Donald Poon

Master of Science in Forensic Science Directed Research Projects

The Taurus Judge is a five-shot revolver designed to fire both 410 Bore shotshells and caliber 45 (Long) Colt cartridges. It is marketed as a self-defense firearm by Taurus. As of 2010, the Taurus Judge was “quickly becoming a popular personal defense firearm”.¹ Although it has become somewhat popular, the Taurus Judge and its various models have not had many distance determination studies completed and there is still a dearth of information on how these handguns compare with shotguns when looking at range of fire determinations. This study focused on: how barrel length affected pellet spread patterns produced by …

Effective Laundering Conditions For Ignitable Liquid Decontamination Of Fire Scene Clothing Used By The Bureau Of Alcohol, Tobacco, Firearms, And Explosives, Rebecca K. Whitney

Master of Science in Forensic Science Directed Research Projects

Ignitable liquids such as gasoline and diesel fuel are common accelerants encountered by Certified Fire Investigators (CFIs). These ignitable liquids can be identified by gas chromatography-mass spectroscopy; the presence of particular peaks in appropriate abundances and patterns indicates the presence of compounds found in ignitable liquids. The Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) issues clothing to its CFIs for wear during fire scene investigation. Previous research has identified a method to decontaminate the tools used by CFIs, but no explicit protocol to decontaminate scene clothing has been determined. This study investigated the use of Tide Ultra Stain Release, …

Detection Of Bacterial Lipopolysaccharides Of Escherichia Coli By Direct Analysis In Real Time/Time-Of-Flight Mass Spectrometry, Dakotah M. Biller

Master of Science in Forensic Science Directed Research Projects

Lipopolysaccharides (LPS) are a major component of the outer membrane in Gram-negative bacteria species and are responsible for toxicity caused by organisms such as Escherichia coli (E.coli). Conventional methods for characterizing LPS utilize mass spectrometry, particularly matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) and liquid chromatography mass spectrometry (LC-MS). Although these are successful in analyzing intact LPS molecules, they can be time-consuming. Other mass spectrometry techniques, such as direct analysis in real time/time-of-flight mass spectrometry (DART-TOF-MS) could also be helpful in the rapid analysis of LPS molecules without sample extraction procedures. This research focuses on the application …

Development Of An Untargeted Gas Chromatography-Mass Spectrometry (Gc/Ms) Method For The Detection Of Drugs In Wastewater, Samuel A. Miller

Master of Science in Forensic Science Directed Research Projects

Monitoring current illicit drug trends and consumption rates of pharmaceuticals using a non-invasive collection technique is needed to address the present drug use and the growing drug epidemic. Reliance on self-reporting drug use surveys is not always a practical measure of illicit drug use. Wastewater analysis has been used globally as a targeted method for monitoring the consumption of specific illicit drugs. Current existing analytical techniques for wastewater analysis focus on the use of targeted liquid chromatography-mass spectrometry (LC-MS) based techniques. Few gas chromatography (GC) procedures exist for wastewater analysis, and those that do concentrate their methods on a single …

Postmortem Interval Estimation Based On Eukaryotic Community Associated With Soil Under Decomposing Porcine Remains, Amanda M. Haase

Master of Science in Forensic Science Directed Research Projects

Recent studies have shown that bacteria associated with soils under a carcass change significantly both temporally and spatially. These studies were done in both laboratory and field conditions, but with limited replications. In addition, limited information exists on temporal and spatial changes in eukaryotic community structure associated with soil under decomposing remains. This study was designed to fill in these gaps and expand on previous studies to improve postmortem interval (PMI) estimation techniques as well as to identify cadaver decomposition islands (CDI) based on eukaryotic community structure associated with soil under vertebrate remains. To accomplish this goal, soil samples were …

The Utilization Of Sex Hormone Antibodies For Screening And Separation Of Trace Biological Mixtures, Kristin N. Jones

Master of Science in Forensic Science Directed Research Projects

Touch or trace evidence consists of epidermal cells deposited by contact with items such as handled objects, touched surfaces, or worn clothes. This type of evidence has surpassed most other sample types submitted to forensic labs and typically consists of low quantities of DNA and multiple contributors. In this study epithelial skin cells, i.e., “touch/trace evidence,” were used as they are estimated to constitute approximately half of the casework evidence items submitted for DNA analysis. For the optimization of antibody staining, male and female skin epithelial samples from donors were incubated and hybridized with antibodies of various concentrations of Alexa …

Discrimination Of Colorless Fibers By Uv-Vis Microspectrophotometry And Microspectrofluorimetry, Kialani Killinger

Master of Science in Forensic Science Directed Research Projects

Fiber evidence is frequently encountered in forensic casework, and part of a typical fiber analytical scheme involves the detailed study of the color and other physical properties, optical properties, and chemical composition of the fibers in question. Microspectrophotometry (MSP) is commonly used to provide objective color measurements of fibers, eliminating subjectivity that may be present in visual color examinations. MSP can produce color measurements over the ultraviolet (UV) and visible (VIS) regions of the electromagnetic spectrum, as well as emission spectra from fluorescence measurements. In this research, colorless fibers were analyzed by MSP, using both transmission measurements in the UV-VIS …

Development Of A Quantitative Pcr (Qpcr) Based Method For Studying Temporal Dna Degradation In Waterlogged Bone, Isis Thornton

Master of Science in Forensic Science Directed Research Projects

Human activities are often centered around the presence of water, thus it is not surprising that there are many water-related human deaths. Accumulated degree days (ADD), and other aquatic variables may affect DNA retrieval from waterlogged bone. Calcium and collagen in bone can inhibit the PCR necessary to produce an STR profile; the current solution is a time-consuming organic extraction. While there are examples of research on DNA degradation in terrestrial bone over time, there has been little work done on submerged bone samples and they are usually limited to case studies. The major aim of this study was to …

Expanded Testing Of An Integrated Qpcr Mixture Screening Assay Using High Resolution Melt Curve Analysis And Support Vector Machine Modeling, Andrea L. Williams

Master of Science in Forensic Science Directed Research Projects

In the conventional forensic DNA workflow, the number of contributors in a sample is unknown until the final step of STR analysis. We propose a high-resolution melt curve (HRM) mixture screening assay, which uses support vector machine (SVM) modeling of melt morphologies of D5S818 and D18S51 amplicons integrated into a common qPCR-based human DNA quantification kit, to differentiate between single-source samples (and their genotypes) and mixtures at an earlier stage in the DNA workflow (quantification). Previously, using data generated from whole melt curves, 87.5% of single-source samples and 100% of 1:1 mixture samples (2 contributors) classified accurately.

In this study, …

The Effect Of Time And Temperature On The Quality Of Latent Fingerprints On Incandescent Lightbulbs, Varying Donors Age And Sex, Kinaysha M. Collazo Maldonado

Master of Science in Forensic Science Directed Research Projects

Fingerprints are used as a means of identification, but there are no established methodologies to determine time since deposition of latent fingerprints by visual means alone. This research considered the influence of age and sex on the quality of recovered latent prints from lit and unlit lightbulbs from 1 to 10 days, using accumulated degree hours (ADH) to account for both heat and time simultaneously. Two male and two female donors (one of each aged40 years) were used. A thermal imaging camera was used to monitor the lightbulbs top and middle regions, which were significantly different (p≤0.05) for the experimental …