Celebrating Student Research

Celebrating Student Research

Presented at the 2019 NEAFS Meeting in Lancaster, PA
November 12th–16th: The Lancaster Marriot

Student: Julian Beach
Study: The Relationship between Terminal Velocity and Glass Fracture via. 177 Caliber Steel BBs

Glass is an abundant material in the environment, and can also be an abundant material found at crime scenes. It may often be the only thing between a bullet and its intended target, which is where fractography is necessary. Fractography is the study of fractured materials, such as glass. The majority of bullets will perforate or shatter most categories of glass; however, in some cases, the bullet may not have sufficient energy to shatter the glass at all. Correlating the terminal velocity of the projectile to the degree of glass fracture can provide useful information regarding the muzzle-to-target distance for a particular firearm/ammunition/glass combination. The experimental methodology was developed through pilot studies covering suitable muzzle-to-target distance ranges, the number of pumps required to pressurize the air rifle propulsion system, and the means of measuring the ricochet distance for projectiles which do not perforate the glass substrate. The goal of this research was to characterize the relationship between impact velocity and glass fracture pattern which can be useful in crime scene reconstruction.

Julian Beach
Graduate Student Julian Beach presenting on bullet velocity measurements

Presented at the 2019 NEAFS Meeting in Lancaster, PA
November 12th–16th: The Lancaster Marriot

Student: Jaclyn Beshlian
Study: A Microspectral Analysis of Synthetic Wig Fibers

An microspectrophotometer (MSP) enables the scientist to collect absorption and fluorescence spectra of colored samples without destroying the piece of evidence itself. The information can be used to distinguish fibers similar in color from each other. This study used an MSP determine whether differentiation between 20 visually similar light brown synthetic wig fibers was possible. Prior to any analysis with the MSP, the material of the fibers was verified through FT-IR ATR, as well as their optical properties. Using a lab-assembled MSP the absorbance measurements were obtained perpendicular and on a 45-degree angle to the polarizer. After the absorbance measurements were complete the fibers were then exposed to fluorescent light. The fluorescent lighting used contained a series of UV, blue, and green 102 excitation filter combinations. No single fiber displayed the exact same spectra to another, allowing differentiation. When combining the information obtained through the absorbance measurements and the three excitation filter combinations, differentiation of all 20 visually similar light brown synthetic wig fibers was achieved


Graduate Student Jaclyn Beshlian pictured with her poster on synthetic wig fiver characterization

Presented at the 2019 NEAFS Meeting in Lancaster, PA
November 12th–16th: The Lancaster Marriot

Student: Ashley Borrego
Study: An Exploration of Protein and DNA components in Fingerprint Components

The main focus of this project was to investigate the protein and DNA components in both sebaceous and eccrine fingerprints and explore a possible correlation to visual fingerprint residue. Twenty volunteers were instructed to touch their face to produce sebaceous prints, and five volunteers were instructed to wear gloves over a heat source to produce sweaty or eccrine prints. Microscopy was used to score the cellular debris of the right fingerprint on a scale of 1-4 based on density of cellular debris. The results of the study illustrated that sebaceous samples that sebaceous samples contained significantly more DNA than eccrine samples, while the number of proteins via mass spectrometry was similar. Accordingly, sebaceous samples had better STR results with 75% full profiles compared to the 20% full DNA profiles of eccrine samples. Linear regression results indicate a lack of correlation between cellular debris scores and DNA yields in sebaceous samples, a strong correlation between the cellular debris and DNA yield in eccrine samples, and moderate correlations between the cellular debris and number of proteins in both sample types. The results of this study provide additional information about donor variability/shedder status, and the content of DNA and proteins in fingerprint samples.


Graduate Student Ashley Borrego pictured with her poster on DNA and proteins in fingerprints


Julian Beach, Professor Linda Rourke, Jaclyn Beshlian, and Ashley Borrego at NEAFS Meetingin Lancaster, PA 2019

2019 Congress of the International Society for Forensic Genetics in Prague, Czech Republic

September 9th–13th: Prague Congress Center

Student: Tebah Browne
Study: Semi-Quantitative Detection of Signature Peptide in Body Fluids by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

This study covers a modified semi-quantitative approach to detecting signature peptides for body fluid identification. A liquid chromatography tandem mass spectrometer normally used for toxicology was adapted to detect target ion transitions for five semen or saliva specific peptides. Peptide concentrations were measured based on a mixture of synthetic peptide standards. Samples were processed using a three-hour trypsin digestion and Microcon membrane filtration. This method generates PCR compatible DNA and peptide fractions that can be typed without any further treatment. Preliminary validation tests covered stains on different substrates, semen/saliva mixtures, limit of detection, and repeatability. All signature peptides were present at different concentrations, varied amongst donors, and were tissue specific. Saliva peptides were detected at lower concentrations and had a higher limit of detection (LOD). Semen peptides had higher concentrations and were detected even as a minor component in a mixture. All semen peptides and all, but one, saliva peptides were detected on the various substrates. DNA fractions did not show signs of degradation or PCR inhibition. The results indicate that this assay is feasible for DNA and protein identification.


Graduate Student Tebah Browne pictured with her poster on protein based body fluid identification

2019 NEAFS Meeting in Lancaster, PA
November 12th–16th: The Lancaster Marriot

Student: Dino Robinson
Award: George W. Chin Memorial Scholarship

Graduate Student, Dino Robinson, was honored with a George W. Chin Memorial Scholarship award at the 2019 North Eastern Association of Forensic Scientist Meeting. This award is given to students who display excellence in his/her academic program.


Graduate Student Dino Robinson and NEAFS Award chair Danielle Malone.

2019 Society of Forensic Toxicologists (SOFT) Meeting in San Antonio, TX
October 16th–18th: Grand Hyatt San Antonio

Student: Victoria Mei

Award: SOFT Educational Research Award

Study: Validation of a Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Method for the Quantification of 13 Designer Benzodiazepines in Postmortem Blood

The ease of purchasing designer benzodiazepines on the internet has increased their misuse. Their use for drug-facilitated sexual assaults is a growing threat. Their use as an alternative to prescription benzodiazepines causes major safety concerns, because the lack of dosage information can lead to unintended overdoses, coma, or death at higher doses for self-medicating users. More data on the quantification of designer benzodiazepines in forensic cases are needed. The main objective of Ms. Mei’s study was to develop and validate a method for the determination of 13 designer benzodiazepines in postmortem blood, to add to the in-house method that already included a limited number of common designer benzodiazepines. The validated method succeeded to simultaneously identify all 13 designer benzodiazepines in blood using solid phase extraction (SPE) and a 13.5-minute analysis on the LC-MS/MS, and proved to be simple, reproducible, sensitive, and robust.


Graduate Student Victoria Mei with her mentor Marta Concheiro-Guisan

2019 American Academy of Forensic Science 71st Annual Scientific Meeting in Baltimore, MD

February 19th–22nd: Baltimore Convention Center

Student: Patrick McLaughlin
Study: Improved DNA Recovery from Handwritten Documents

When paper evidence is submitted for evidence recovery, a common practice is to prioritize the chemical or physical development of latent prints prior to attempting any of the various methods of DNA extraction from the prints. Areas of the periphery are commonly targeted for print visualization where people most commonly hold and lift sheets of paper. The written text is rarely considered an area of interest for criminalists but has the potential to retain “touch” DNA evidence deposited when the writer of scraped their hand across the page during the writing process. In this study we asked male and female volunteers to produce handwritten documents. Additionally, a “field case” study was performed where volunteers provided a writing sample prior to and after a mild aerobic exercise period. The writing samples were then vacuumed using an irradiated and trimmed glass pipette containing a moistened cotton Puritan swab with a vacuum hose attached to the narrow end of the pipette. The quantity of recovered DNA varied greatly from donor to donor, but most of the collected samples provided sufficient material to for STR typing and successful comparisons to the reference samples. This technique did not affect latent print and indented markings. Additionally, the process does not damage the document, which may be of importance for prosecutorial value and court demonstration.


Graduate Student Patrick McLaughlin with Professor Prinz and other members of the Prinz research group

Presented at the 2018 NEAFS Meeting in Bolton Landing, NY
October 23rd–27th – The Sagamore Resort

Students: Niti Dalal and Patrick McLaughlin, Mentor Mechthild Prinz
Study: Optimizing a method for DNA recovery while preserving latent prints on paper

The evidence in criminal cases like kidnapping, extortion and bank robberies often consists of handwritten paper documents where both latent print processing and DNA collection are important. This project tested a workflow, where adhesive tape and dry swabs were used to remove DNA from the surface of the paper without destroying the fingerprint pattern underneath. With a higher DNA yield and better success rates for fingerprints, tape was more suitable than swabs. Tape DNA collection even worked after latent prints had been made visible through fluorescent powder. 


Graduate student Niti Dalal pictured in front of her poster

Presented at 2016 NEAFS Annual Meeting in Atlantic City. New Jersey
October 12th - 16th – Harrah’s Resort and Casino

Students: Melissa Branker, BSc; Jennifer Rosati, PhD
Study: The importance of resource quality and species interactions
on the colonization behavior of the black blow fly, Phormia regina (Meigen).

Within minutes after death, the process of decomposition occurs, which modifies the morphology and structure of a corpse (Campobasso et al, 2001). During decomposition, there are a wide variety of insect groups that arrive and utilize carrion with a distinct pattern of insect succession (Campobasso et al, 2001).  There are many forensically important Dipteran species that are known to colonize a decomposing carcass during the early stages of decomposition, which include the families of Calliphoridae (blow flies), Sarcophagidae (flesh flies) and Muscidae (house flies). Within the first few hours post-mortem, blow flies are known to have high levels of recruitment to the resource (Campobasso et al, 2001).  As a result, blow flies are commonly used as indicators to determine the minimum time of colonization (MTC); which can be helpful in post-mortem interval (PMI) estimations.  However, the colonization behavior of these indicator species can be influenced by a variety of factors including oviposition preference (Campobasso et al, 2001), pheromone cues (Yang and Shiao, 2012, Akol et al 2013), bacterial cues (Lam et. al 2007, Zheng et al 2013) as well as inter- and intra- specific interactions. (Giao and Godoy, 2007, Yang and Shiao, 2012). This research utilized two forensically relevant blow fly species: Lucilia sericata (Meigen) and Phormia regina (Meigen) to examine the effects of resource quality and species interactions on the oviposition behavior of blow flies. We hypothesize that both resource quality and the presence of L. sericata eggs will alter the colonization behavior of P. regina.

Team Rosati pictured in front of Melissa's poster on Forensic Entomology
(Graduate students Melissa Branker, Vincent Nappi, and undergraduate Veena Mehta)

54th Annual Meeting of TIAFT
Brisbane, Australia
August 28th – September 1st, 2016

Student: Briana Miller
Study: Stability of Synthetic Cathinones in Preserved Oral Fluid Specimens

Dr. Nikolas Lemos wanted to commemorate the 20th anniversary of his graduation from John Jay with a master’s degree in Forensic Science, and honor his late mentor, Professor Agarwal by sponsoring a current graduate student to attend the 2016 meeting of TIAFT, to be held in Brisbane, Australia. Briana Miller was that lucky student and she had the opportunity to present her paper on “Stability of Synthetic Cathinones in Preserved Oral Fluid Specimens”.


 

Presented at the American Association for Crime Scene Reconstruction Training Conference
2016 in Clark, New Jerey

Students: Tara Goldfrank; Peter Diaczuk, PhD
Study: Critical Angle Determination & Angle of Ricochet on Windshield Glass 

Bullet trajectories are a critical element in crime scene reconstruction.
This study explores the variability of ricochet angles specifically for
windshields since shooting events often include vehicles.

Presented at the Eastern Analytical Symposium and Exposition,
2014 in Somerset, NJ

Students: Kristi Tami; Gloria Proni, Phd.
Study: Spectroscopic Characterization of Organophosphate Compounds

Most commercially important insecticides and lethal chemical warfare agents belong to the category of organophosphate compounds. Their mode of action is related to the accumulation of acetylcholine at the synapses that culminates in respiratory failure and neurological damage. We are investigating the toxicity of selected organophosphate compounds in respect to their structures' spatial differences.

Presented at the 66th Annual Scientific Meeting of the American Association of Forensic Science, 2014 in Seattle, WA.

Students: Theron Ng-A-Qui, B.S.; Bruce Eng, J.D.; Shu-Yuan Cheng, Ph.D.
Study: Extraction process efficiency study of cathinones by solid phase extraction

This study explored current limitations when dealing with synthetic drugs. Despite the increased availability of designer drugs, few studies have focused on the analytical extraction techniques for their detection and quantification in biological samples. With solid phase extraction (SPE) being the most commonly used technique for sample preparation, it is important to know the rate at which the target substances are being recovered. The results indicate that the Strata X Drug B SPE extraction was able to recover higher percentage of cathinone and mephedrone at medium (100 ng/ml) and high (500 ng/ml) concentrations, but not at low (10 ng/ml) concentration.

Presented ath the 2013 NEAFS Annual Meeting
September 25th – 28th, 2013, in Cromwell, CT

Student: Laura Pritchard
Study: Establishing a method to determine the Statistical Value of Fiber Evidence

Recent MS-FOS graduate Laura Pritchard presented her poster on "Establishing a method to determine the Statistical Value of Fiber Evidence". Dryer lint from 14 dryers was collected to show that each crime scene can be unique. A sample from each was mounted on its own microscope slide and then analyzed with a polarized light microscope. Color, cross sectional shape, parallel refractive index, perpendicular refractive index, dichroism, and birefringence of each fiber in the sample sets were captured and data were analyzed using Fisher’s Exact test. Her mentor for this project was Professor John Reffner.