Forensic Science - Undergraduate Theses
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Item Development and validation of a method for the determination of nine benzodiazepines and metabolites in dried blood spots (DBS) using UPLC-QTOF-MS(2017-07-20) Hill, Seana L.In forensic toxicology benzodiazepines are common compounds implicated in drug impaired driving cases. Detection of these compounds is ideally determined from whole blood collected from the individual after impairment has been established and qualified personnel are available to draw blood. This study focused on the development and validation of a screening method that could also be applied to quantification of a set of nine benzodiazepines and metabolites extracted from dried blood spots and analyzed using UPLC-QTOF-MS: diazepam (DZP), temazepam (TMZ), oxazepam (OXZ), nordiazepam (NOZ), lorazepam (LRZ), clonazepam(CLZ), 7-aminoclonazepam (7CLZ), alprazolam (APZ), and α-hydroxyalprazolam (aHAM). Advantages of DBS over whole blood sampling are less invasive sampling, potential for increased stability of analytes in the card matrix, small sample volumes, simplified extraction and ease of storage and transport. All dried blood spots were 20 μL of sheep blood spiked with a 2.86μg/mL mixture of the compounds included in this study and left to try overnight at ambient temperature. The optimized method immersed a ½” diameter punch of card containing the entire blood spot in an extraction solvent of 1:1 (v/v) methanol:acetonitrile and sonicated for 30 minutes. The extraction solvent was separated from the spot, 1 mL of acetonitrile was added followed by protein filtration. Filtrate was evaporated down to dryness and analytes were then reconstituted in 1:1 (v/v) acetonitrile:water before analysis. Each step of extraction and sample preparation was optimized for this study. All analytes were stable within the card matrix for 14 days under refrigeration at 4°C. All analytes were stable up to 12 hours in the autosampler of the instrument. Hematocrit over a range of 20 - 70% did not affect interpretation of results. Validation produced calibration curves over a range of 7.8 – 500 ng/mL that had R2 values ranging from 0.998-1.00 with a quadratic line of best fit. Bias was <20% for high blind samples and ≤25.6% for low blind samples. A screening method using UPLC-QTOF-MS to analyze DBS extracts able to identify all benzodiazepines of interest was developed and validated. Calibration curves representing impairment ranges of the analytes of interest predicted concentrations within a reliable range that allowed for quantification of the analytes.Item Preliminary investigation into the usefulness of tattoos for identification purposes(2017-07-20) Grenier, Larysa NicoleTattoos are common distinguishing features of many people in today’s populations, however, investigation into their usefulness in a forensic context is only just up-and-coming. This study uses four ink colours common in tattoos and the Northeastern Ontario fall and winter climates to see how study tattoo composition in skin is when presented in a harsh environment. Ten samples of tattooed pork (Sus scrofa) shoulder with skin attached were left out in the environment for 141 days. Upon collection, eye-visual analysis as well as technological analysis via photographs were done on the colours to determine change. Visually changes were not noted in most samples but, using CMYK and classified Pantone® colours, slight differences were noted. This study shows the preservative properties of a Northeastern Ontario winter and raises areas of future study for the usefulness of tattoos as an identification tool in forensic casework.Item A investigation of the relationship between fracture type and force: blunt force trauma on mammalian juvenile ribs (Sus scrofa, linneaus)(2017-07-20) Boyd, Katie A.The interpretation of bone trauma is an important aspect in understanding the circumstances within a death investigation (1-3). Proper interpretation of fractures can aid in identifying the number of blows, impact sites, the order in which they occur and the amount of force required to inflict such wounds (1,2). Yet there is a paucity of research regarding the force applied through the utilization of blunt implements used to inflict trauma. Such a study has the potential of more accurately characterizing the trauma, with regard to the amount of force used to create observed fracture patterns. In this preliminary study, a computer controlled impacting machine was used to inflict direct trauma onto several full, semi-fleshed racks of juvenile pig ribs (Sus scrofa, Linneaus) with a hammerhead attachment (n=36). Although there has been a recent interest in fracturing devices (2, 4-6), this one differs in that it mimics the arching motion of a human overhand swing, and is able to inflict trauma onto fully fleshed and intact specimens. After each strike the force at the moment of impact was recorded and was later paired with its corresponding fracture. From there, the range of force associated with transverse, oblique, spiral, greenstick, and comminuted fractures, as well as having no fractures at all were examined in light of the recorded forces. Such results were compared to those of others performed prior to work on the machine to determine if such relationships were consistent between studies. In this study it was discovered that there is no threshold where one fracture group will start and another will end.Item Bullet calibre and types estimation from gunshot wounds in sus scrofa (linnaeus) long bone(2017-07-20) Henwood, Bailey J.The calibre of bullet used in the commission of crime is not typically ascertained from a wound in soft tissue, and cannot be reliably determined from the damage done to flat bones (1, 2). This study examined the feasibility of obtaining both bullet calibre and type from ballistic damage to long bones. Thirty fresh pork shoulders (Sus scrofa), in three groups of ten, were each shot with a handgun using one of three calibre. These calibres were of two bullet types, either lead or full copper jacket. Each pork shoulder was shot through the intact humerus with either a 0.22 round-nose lead bullet, 9mm full copper jacketed bullet, or a 0.38 round-nose lead bullet. The long bones were subsequently defleshed and examined for evidence of bullet calibre and type. The damaged bone was reconstructed to the fullest extent possible from the resulting bone fragments. The minimum diameter of each entrance wound, as well as the associated fracture pattern, were recorded. A Kruskal-Wallis nonparametric test was used to compare the median entrance wound measurements for each calibre. Cortical bone spalling was seen only In long bones shot with a copper jacketed bullet. This is due to the differing energy propagation of the two bullet types through the bone tissue. Our study demonstrates that bullet type can be ascertained from long bone damage, and the damage from a 0.22 calibre bullet can be distinguished from that of a 0.38 or a 9mm bullet.Item Analysis of the effects of short-term subaerial weathering in different environmental conditions on bone colour and microstructure.(2016-07-13) Bouzane, CéciliaThis preliminary study was conducted in order to evaluate the effect of subaerial environmental factors on bone colour change over time, and to quantify this using photography and Photoshop© CMYK analysis, as well with the Munsell Soil Colour Chart®. Additionally, surface microstructural changes with macroscopic and scanning electron microscopic (SEM) analysis were also conducted. Environmental data were tracked, and vapour density was documented and compared to relative humidity to determine the best-suited unit of measurement. The specimens consisted of 23 fleshed Sus scrofa humeri that were exposed to different microenvironments with varying sustrates and sunlight exposure. Although no discernable colour change trends were observed, other taphonomic changes were visible macroscopically in as little as 6 weeks to a few months of environmental exposure, and detailed distinctions could be made between specimens of different groups using SEM analysis.Item Dextromethorphan and its matabolites in rat bone tissues by gas chromatography-mass spectrometry analysis following differential microclimate decomposition(2016-07-13) Unger, KirkThe effect of microclimate on dextromethorphan (DXM) and dextrorphan (DXT) responses in skeletonized rat remains was examined. Animals (n=10) received dextromethorphan at 75 mg/kg by i.p. injection for comparison against drug-free controls (n=4), and across different decomposition sites. Rats were divided equally into two groups and placed at different sites for decomposition immediately following euthanasia (30 minutes post dose). Rats at Site A decomposed in a shaded forest microenvironment on a grass-covered soil substrate. Site B animals rested on rock and gravel substrate exposed to open air and direct sunlight. Site A and Site B are approximately 600 m apart. Ambient temperature and relative humidity measurements recorded by data loggers mounted 3 cm above rats at each site established microclimate differences. Bone elements (vertebrae, ribs, pelvic girdles, femora, tibiae, humeri and scapulae) were harvested, cleaned and pulverized for Microwave Assisted Extraction in methanol. Drug and metabolite extractions were isolated by solid phase extraction prior to GC/MS analyses. Mass normalized DXM and DXT levels and metabolite/drug ratios were compared across different bone elements (within and between animals) and microclimate sites. Concentrations calculated from drug responses and standard curve plots gave estimated concentrations of 399 to 10,474 ng/g for DXM and 132 to 3,668 ng/g for DXT. Max/min values across animals and bone elements examined response variation. No significant differences in DXT levels or metabolite/parent ratios were observed between sites or across different bone elements. The only significant difference for DXM levels were found in femurs compared across microclimate sites. Microclimate showed no significant influence on observed DXM or DXT values, indicating bone as a drug reservoir may behave uniformly for certain drugs across different environments of decomposition. The results of this study show limited agreement with previous work from our laboratory on drug recoveries from decomposed bone tissues.Item A preliminary study of blunt force trauma using a new computer-controlled impact device: an exploration of force and fracture type using domestic pig juvenile ribs (Sus scrofa domesticus)(2016-07-13) Holinier, CharlotteWhen studying bone trauma, many questions have to be answered such as identifying the type of trauma, the timing and the force used to cause the injury. The latter is difficult to answer, as no previous studies have been able to provide concrete data to determine the force. This study focuses on blunt force trauma to the ribs using a hammerhead, and studying the potential relationship between the type of fractures and the induced force. To do so, a newly constructed, computer-controlled impact device was utilized to strike juvenile domestic pig ribs and record the force at the moment of impact with an incorporated load cell. A total of 20 ribs were struck perpendicular to the long axis of the rib on the external surface, inducing 21 fractures. Transverse fractures were the most prevalent type observed. Upon examination of the applied force, no significant differences in the force applied were found between all of the different categories of fractures, with the exception of transverse and oblique groups with the nonfractured group.Item Evaluation and modification of a micromanipulation technique and stubbing method for the collection of touch DNA(2016-07-13) Kay, MelissaTouch DNA is the essence of Locard’s Exchange Principal at a microscopic level – when two objects come into direct contact there is an exchange of materials. Tapelifting has been shown to be the superior method for the collection of touch DNA, in part because it excludes common PCR inhibitors. This study looked into refining the tapelifting method using a modified aluminum stub that is often used in gunshot residue collection or scanning electron microscopy. This stubbing method provides barriers that reduce the risk of contamination, such as the distance between collector and evidence. Substrates that were used for collection included wood, clothing, and writing utensils. In addition, this study looked at a micromanipulation technique that involved the collection of bioparticles using a water-soluble adhesive, while being viewed under a microscope. There were modifications made to the micromanipulation protocol that was outlined by Farash et al. in their paper. One modification was the inclusion of the extraction and quantification steps. PrepFiler Express and PrepFiler Express BTA extraction kits were both used to compare any differences. The PrepFiler Express yielded more results, including the only full profile. The micromanipulation technique and the stubbing method both proved to be adequate methods for the collection of touch DNA.Item Validation of the use of Sus Scrofa (domestic pig) DNA as a research tool in a forensic laboratory(2016-07-13) Bennoit, NathanFor a number of years, pigs have been used in a variety of forensic disciplines as a research tool, such as in forensic anthropology. However, pigs have not been used as a research tool in forensic DNA analysis. The use of pig DNA is becoming common in different areas of forensic science such as wildlife management but the transition to forensic DNA research has not happened yet. This paper proposes that pig DNA can be used in a forensic setting for research purposes in a lab that also conducts case work. The methods followed for the development of an STR profile using a commercial multiplex kit for pigs are the same as the standard procedure in a forensic Human DNA laboratory. The validation showed that pig DNA can be analyzed with the equipment currently used for human samples and it does not cross contaminate human samples. These factors would help small labs conduct both research and casework within the same laboratory.