Digital Commons Network^™

Qualitative And Quantitative Characterization Of Epithelial Cell Mixtures Using Hormone Antibody Probes And Flow Cytometry, Luke Baldridge

Master of Science in Forensic Science Directed Research Projects

“Touch” DNA is evidence that consists of epidermal cells deposited by handling objects and it is becoming more common in evidence samples processed in crime labs. Because “touch” DNA evidence samples may be low-template DNA and are often mixtures, there is a need to both nondestructively estimate the amount of DNA present prior to DNA purification and to identify and characterize mixtures prior to DNA typing. The purpose of this study was to test the use of FITC-labeled anti-testosterone antibodies as a potential tool to estimate the number of contributors in two-, three-, and four-person mixtures of epidermal skin cells, …

Identification And Optimization Of Mirna Biomarkers For Body Mass Index (Bmi) Estimation In Forensic Samples, Jennifer J. Shealy

Master of Science in Forensic Science Directed Research Projects

DNA profiles do not provide as much evidentiary value when either all known samples can be excluded or when there is no known suspect. DNA phenotyping is a technique used for investigative purposes to predict externally visible characteristics (EVCs) based on specific markers found in the genome. Most phenotyping panels are currently restricted to markers stable over a lifetime within an individual and are not able to predict environmental or metabolic impacts on EVCs. It is known that miRNA expression levels change due to environmental and metabolic factors, such as BMI, and research has proven associations between circulating plasma miRNAs …

Quantitative Pcr And Sanger Sequencing Of Mitochondrial Dna Recovered From Waterlogged Bone, Kailey Babcock

Master of Science in Forensic Science Directed Research Projects

In forensic contexts, samples containing heavily fragmented DNA are commonly encountered. Compromised biological samples are especially prevalent in instances where human remains have been submerged in an aqueous environment for extended periods of time. Nuclear DNA is particularly vulnerable to the prolonged exposure to heat, moisture, and bacterial degradation that are prevalent in aquatic settings. Paired with the difficulty of recovering DNA from skeletal remains, which are often the only remaining component after the soft tissues have been stripped away, mitochondrial DNA (mtDNA) analysis serves as an invaluable alternative. In this multifaceted study, mtDNA analysis was performed on waterlogged bone …

Detection Of 2,4,6-Trinitrotoluene Using A Colorimetric Gold Nanoparticle Air Cassette Filter, Andrea I. Ferrer Vega

Master of Science in Forensic Science Directed Research Projects

Trinitrotoluene (TNT) is an explosive commonly used during military and terrorist activities. Current methods to identify this compound require sampling, transport and analysis at a forensic lab using analytical instrumentation. However, on-site detection is needed to assist efforts to prevent detonation. Gold nanoparticles have been used as sensors throughout the years due to their versatility and surface enhanced Raman scattering properties in the presence of an analyte and low limits of detection. By taking advantage of the Meisenheimer complex that TNT forms in the presence of amines, it is possible to determine its presence at picogram levels. Subsequently, adhering amine …

Differentiation Between Peripheral Blood And Menstrual Blood Using Mirna Markers, Anaya Valentine

Master of Science in Forensic Science Directed Research Projects

Abstract

In forensic investigations, body fluids can provide crucial information and is helpful for corroborating the circumstance of the case. For cases of sexual assaults or homicides, being able to differentiate if the blood is peripheral blood or menstrual blood is important. Peripheral blood can be indicative of a traumatic event, while menstrual blood is of a natural cause. Currently, serology based methods are used for body fluid identification, however, their lack of sensitivity and specificity remains an issue. MicroRNAs (miRNAs) are a class of non-protein coding nucleic acids that are able to be co-extracted with DNA, and their small …

Characterizing The Presence Of Edta In Blood Samples, Alexandra Wright

Master of Science in Forensic Science Directed Research Projects

Blood is often a type of evidence found at crime scenes. There has been a long history of criminal cases involving blood evidence samples that were allegedly planted at the scene by a third party. Ethylenediaminetetraacetic acid, or EDTA, is an anticoagulant that is not naturally occurring in blood samples; it chelates to ions in blood to prevent clotting. If present in a blood evidence sample, it could be indicative that the blood sample may have been planted at the crime scene to implicate a suspect. EDTA is also reported to modify clothing and exist in detergents, to allow dyes …

Development Of An Analytical Method And Sample Preparation Technique For The Analysis Of Sulfur-Containing Fentanyl Analogs By Uplcmsms, And The Application To Forensic Science, Amber D. Budmark

Master of Science in Forensic Science Directed Research Projects

In February 2018, the US DEA Agency released a statement of the emergency scheduling (Schedule 1) of all fentanyl analogs not already regulated by the CSA due to an alarming increase in overdose deaths linked to synthetic opioids. Fentanyl analogs are pharmacologically similar to fentanyl, but often more potent. This increased potency can create problems with proper dosing of fentanyl analogs leading to untoward effects including an increase in overdoses and deaths. Since 2018, there has been a 38.4% increase in illicitly manufactured fentanyl overdose deaths leading the CDC to make available the FAS Kit and Emergent Panels containing previously …

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. …

Identification Of Compounds Causing Cellular Autofluorescence In Touch Samples, Elora C. Wall

Master of Science in Forensic Science Directed Research Projects

As DNA analysis has advanced and produced tests with higher sensitivities, attention has turned toward obtaining DNA profiles from cells left with fingermarks. Recent studies have reported that cells deposited within fingermarks can exhibit differences in autofluorescence emission in the ‘red’ region of the visible spectrum (e.g., between 650-670 nm), which can be used to differentiate contributor cell population and separate them before DNA profiles. Interestingly, this emission was not consistent to the individual day-to-day and likely not a genetically-controlled attribute of the contributor. Instead, this emission signature results from extended exposure of the skin to certain materials such as …

The Impact Of Latent Print Processing On Firing Pin And Breechface Impressions During Firearm Examination, Brittany B. Harrington

Master of Science in Forensic Science Directed Research Projects

Latent prints can be a valuable source of forensic evidence when solving a crime. They can verify if a person was at a specific scene, identify unknown individuals to connect them to a scene, and help to corroborate eyewitness accounts. Latent prints, however, are not always visible until they have undergone enhancement or visualization techniques. When fired cartridge cases are suspected of containing latent prints, they are brought in for latent print processing before any firearm analysis is performed. As a result, these cartridges are often coated in various residues or dyes when they arrive for firearm examination. In response, …

Powerplex® Fusion 6c System Versus Powerplex® Fusion 5c: A Comparison Of Performance Metrics, Caitlin M. Mccaughan

Master of Science in Forensic Science Directed Research Projects

Following the FBI mandated expansion of the CODIS core loci from 13 to 20, several manufacturers developed short tandem repeat (STR) typing kits in response to the new criteria. One such manufacturer was the Promega Corporation, which released the PowerPlex® Fusion 5C megaplex STR typing kit (Fusion 5C) in 2012. Currently, the Virginia Department of Forensic Science (VDFS) utilizes this amplification kit for both casework and database applications. In 2015, Promega released the PowerPlex® Fusion 6C STR typing kit (Fusion 6C), which contains three additional loci beyond those included in PowerPlex® Fusion 5C, and a sixth color channel. The power …

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 …

Comparison Of Semi-Automated And Manual Differential Separation Methods For Mock Sexual Assault Samples, Stephanie Rink

Master of Science in Forensic Science Directed Research Projects

In the event of a sexual assault, separation of suspect from victim DNA is possible through differential extraction if the evidentiary mixture consists of female epithelial cells and male spermatozoa. The basis of differential extraction is the differing properties of epithelial and sperm cell membranes, specifically the comparative sturdiness of the proteins making up the sperm head containing the male DNA. Effective retrieval and separation of male and female DNA fractions is important in generating high-quality STR profiles that can be utilized in identifying suspects in a sexual assault case. Differential extraction has been conventionally performed using Proteinase K (PK) …

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 …

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 …

Evaluation Of Five Methods To Develop Latent Prints On Thermal Paper, Jenna Pregent

Master of Science in Forensic Science Directed Research Projects

Forensic latent fingerprint laboratories determine the proper techniques for fingerprint visualization based on the substrates upon which they are deposited. Typical forensic analysis of thermal paper evidence involves the application of ninhydrin and/or 1,2-indanedione dissolved in a polar solvent. However, polar solvents create an undesirable reaction with the thermal paper’s internal properties and often lead to discoloration of the evidence. When this occurs, not only are the fingerprints less likely to be visible due to the loss of contrast, but the evidentiary print on the receipt may be lost entirely. This research sought to compare five development methods to determine …