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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

DEVELOPMENT OF AN EXTRACTION METHOD FOR THE MASS SPECTRAL ANALYSIS OF ORGANIC GUNSHOT RESIDUE FROM CLOTHING

Casper, Brent 01 January 2015 (has links)
This dissertation will focus on the extraction of volatile organic compounds associated with gunshot residue from articles of clothing, followed by analysis with mass spectrometry. During the discharge of a weapon, a cloud of volatile organic gunshot residue (OGSR) is dispersed around a firearm. This will create a high probability of transfer between the OGSR and the clothing of individuals who are near a discharged weapon. The first part of this dissertation will be the development of a method for removal of volatile OGSR from articles of clothing. Extraction of OGSR will be completed by solid phase microextraction (SPME), followed by separation and analysis by gas chromatography-mass spectrometry (GC/MS). Many parameters will require optimization for proper extraction of OGSR from articles of clothing. Following development of a SPME procedure, figures of merit were determined such as linearity and limits of detection/quantification, obtaining levels of detection of 0.206 ng/cm2 on a 100 cm2 cotton cloth. Applications of this extraction method were investigated including the determination of the distance OGSR travels from a discharged weapon and the extraction of OGSR with different clothing materials by SPME. The second part of this dissertation will focus on the development of an on-line solvent extraction method for removal of OGSR from articles of clothing, followed by analysis with paper spray mass spectrometry. Issues using SPME of certain types of clothing materials required the development of an alternative method for removal of OGSR from articles of clothing. Use of an on-line solvent extraction technique of OGSR from articles of clothing followed by analysis with paper spray mass spectrometry allowed for detection of OGSR at comparable levels to a headspace SPME procedure. Use of paper spray with an ion trap mass spectrometer permitted the soft ionization of OGSR compounds followed by tandem mass spectrometry to obtain structural information. Extraction of OGSR from articles of clothing has potential to determine if an individual was present during the discharge of a firearm. Extraction of OGSR from articles of clothing will provide an alternative to traditional methods of gunshot residue analysis currently in use.
202

An assessment of pipette calibration stability using statistical process control charts

Pruckler, Rachel 05 November 2016 (has links)
Routine pipette calibration is an essential part of any quality assurance and quality control program in the forensic sciences and beyond. Pipette calibration standards in a forensic laboratory are typically set to the limits outlined by the document ISO8655, published by the International Organization for Standardization for the general scientific community. Alternative methods exist that may be capable of monitoring pipette stability across time in a forensic setting. Statistical process control charts, or Shewhart charts, are one such form of process control, which is being investigated for its potential application to pipette calibration monitoring for forensic DNA laboratories. Indeed, the application of process control lines for monitoring the calibration of volumetric equipment is not without precedent.1 To investigate the applicability of process control charts for monitoring pipette stability, a series of X ̅ and S charts, a type of Shewhart chart, have been produced from eight years of collected calibration data. A total of 71 pipettes of the following sizes were examined: 1-10 µL, 1-10 µL multi-channel, 10-100 µL, 100-1000 µL, 1-3 µL, 30-300 µL, 5-50 µL, 5-50 µL multi-channel, and 500-5000 µL pipettes. The ISO8655 calibration recommended volume limits of these pipettes have been added to the charts for the purposes of comparison. With these charts, it is possible to assess pipette performance over time in comparison to the ISO8655 calibration standards and to the control limits imposed by the Shewhart charts. The completed charts suggest that the methodology proposed by Shewhart shows promise as a supplement to ISO8655 recommendations for monitoring pipette stability across time. To corroborate the value of using Shewhart charts to monitor pipette performance, a serial dilution study in conjunction with a series of simulations with dynamic modeling software was performed. This dilution study investigated whether the systematic biases shown by the Shewhart charts could be measured in a laboratory setting. The simulations investigated multiple hypothetical pipetting scenarios concerning various levels of systematic bias. The simulations consistently corroborated the value of Shewhart charts to enforce better compliance between a pipette’s nominal and actual volume delivery, while the serial dilution study offered partial evidence of systematic pipetting bias.
203

The effects of household corrosive substances on restored and non-restored teeth

Trapp, Brittany Megan 03 July 2018 (has links)
A gap in the literature exists regarding the chemical effects of household acids at different concentrations on restored and non-restored dentition. The present study examines the effects of household corrosive products on human dentition. A total of 105 adult teeth consisting of restorations composed of silver amalgam, porcelain-fused-to-metal crowns, and teeth lacking restorative material were used. The household products utilized were hydrochloric acid (Clorox® Bleach Cleaner and The Works® Toilet Bowl Cleaner) and sulfuric acid (Drano® Drain Opener and Watchdog® Battery Acid), along with one control base (Biz® Detergent). Teeth were radiographed before and after exposure to the products and were removed from the solutions after 1, 2, 4, 8, 24, 72, 120 and 264 hours. Documentation included weight, mesiodistal and buccolingual crown measurements, ordinal scoring of alterations, and photography. The results indicate 86% of the teeth could be positively identified by radiographs after exposure. Hydrochloric acid had the most destructive effects to teeth without restorations and those with silver amalgam restorations but had a minimal effect on the porcelain-fused-to-metal samples. Sulfuric acid minimally altered the restored teeth and deteriorated some parts of the enamel and dentin of the non-restored samples. Exposure to the detergent resulted in no change. A logistic regression analysis was conducted to determine if there was statistical relevance in acid type, acid concentration, and the type of restoration of the tooth. Results indicate that acid type, acid concentration and the type of restoration are all statistically relevant for positively identifying an individual through radiographs. The results of this study demonstrate that various household corrosive substances can affect the morphology of teeth, and in some cases, destroy teeth, which could mask the identification of an individual. However, the porcelain-fused-to-metal crowns were minimally affected by corrosive agents and can therefore be used for positive identifications.
204

Rastreamento da origem geográfica de amostras de maconha apreendidas nas ruas de São Paulo, por meio de assinaturas químicas

SHIBUYA, ELISA K. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:50:13Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:58:44Z (GMT). No. of bitstreams: 1 10554.pdf: 11520405 bytes, checksum: 77369e7569e528de44a78a67c7e707b6 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:00/09814-0
205

Multiple Stain Histology of Skeletal Fractures: Healing and Microtaphonomy

Powell, John Wellington 01 January 2015 (has links)
The forensic examination of wounds is one of the key elements of analysis performed by forensic anthropologists and forensic pathologists. Gross examination and histological analysis can be used to determine the timing of the wound and its cause. While forensic pathologists are trained to analyze hard and soft tissue wounds, forensic anthropologists, bioarchaeologists, and paleopathologists, focus on hard tissue. Forensic anthropologists have the added benefit of potentially working with residual soft tissue and would benefit from the incorporation of microscopy techniques that take advantage of the soft tissue to better understand perimortem events. Little research has been published that examines if any healing processes, the defining characteristic of an antemortem wound that do not progress beyond the time of death, are preserved within the tissues beyond death and how long they may be visible. The objectives of this study were to examine if the use of multiple stains will allow earlier visualization of healing processes in skeletal fractures than gross examination and to observe the length of time microscopic healing structures remain visible after death. A total of 224 slides from 19 specimens representing both fractured and un-fractured bones for control samples were taken from nine autopsied individuals at the Hillsborough County Medical Examiner's Office and analyzed using four stains: Hemotoxylin and eosin (H&E), trichrome, Prussian blue, and elastin stain. Slides were analyzed using a set of 14 scored variables and evaluated with nonparametric statistical tests and cluster analyses. H&E, trichrome, and elastin stains were useful in examining wound age and survival time categories were significantly different for presence of elastin and presence of hemorrhage. H&E and trichrome stains proved useful for observing residual healing structures after death and time cohorts after time of autopsy were significantly different for 11 variables. Results from this study support further testing with larger sample sizes, including samples with a wider range of survival time, to better predict survival times of fractures and time since death.
206

DNA profiles generated from minute amounts of single cells

Wenäll, Lovisa January 2011 (has links)
The genetic code in our cells is built up by deoxyribonucleic acid (DNA) with a sequence that is individual and unique to each person. A cell’s origin can be decided by comparing an established DNA profile with a known profile. The most publicly known application is in the forensic field and its use for identification and for establishing a connection between perpetrators and victims or crime scenes. DNA profiling is also commonly used for kinship investigations. The information embedded in the DNA is also used for diagnostic purposes in conventional medicine. Generating DNA profiles is a well-established procedure, which is used daily and for many purposes. An amount of approximately 150-1500 cells is required to be able to establish a full DNA profile using current methods. There are several situations where the amount of material is limited. To enable analysis where the testing material is limited it is of great value to develop a method that can perform these analyses on minute amounts of cells. If there were a method for generating DNA profiles from single cells then mixed samples from crime scenes would be separable. In tumour biology it is also of interest to obtain information from single cells. The aim with the thesis was to establish the smallest amount of cells needed for a full DNA profile. The thesis started with analyses on extracted DNA. During several experiments dilution series were made to investigate the possibilities to establish profiles from minute amounts of extracted DNA. The main methods used during this thesis were polymerase chain reaction (PCR) and capillary gel electrophoresis (CGE). These methods are well-established tools both in biomedical science and at The Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine. Different factors were optimized and the acquired knowledge resulted in application of DNA on FTA® Micro Cards. The cards are used in the daily routines and are easy to use. Several experiments were then performed on peripheral lymphocytes based on the knowledge acquired during the process. Applying a low amount of lymphocytes on FTA cards proved to be very successful and the method generates DNA profiles at a single cell level. The method is applicable for approximately 5-10 cells.
207

Study of the Transport of Odorants from Illicit Substances Using Direct Analysis in Real Time Mass Spectrometry

Zughaibi, Torki A 29 June 2017 (has links)
Canines have been employed in matters of law enforcement because of their keen sense of smell. Presently, law enforcement officials are utilizing trained canines in routine traffic stops to assess if the vehicle contains any illicit substances. Many believe that this is an infringement on an individual’s fourth amendment rights, which has garnered the attention of both the media and the courts. Many questions have been raised with respect to canines alerting to locations where illicit substances were no longer present. Thus, the purpose of this dissertation research is to evaluate the manner in which active odorants transport and persist onto various substrates. Direct Analysis in Real Time (DART) coupled to an accurate-mass time-of-flight (AccuTOF™) mass spectrometer was used to rapidly analyze the volatile organic compounds (VOC’s) from a variety of narcotic and explosive substances. The DART ion source is a soft ionization technique used in ambient conditions to sample liquids, solids or gases in real time. Thermal desorption of the VOC’s could thus be conducted in seconds. The present study found that the VOC’s from illicit substances transport from one location to another, in a short amount of time, through a process known as advection, which may contribute to canines producing unconfirmed alerts during their training and certifications. Three of the four odorants used in this study produced positive results, with the exception being 2-ethyl-1-hexanol, as it was not detected at any time when held at distances between 0.5 and 3 meters. In addition, the amount of time needed for an active odorant to contaminate an object in its immediate vicinity was explored and the results were determined to be inconclusive. Although they were observed following longer exposure times, it was still deemed to be inconclusive since it was still possible for these odorants to be present, albeit not in detectable amounts, at lower exposure times. Controlled odor mimic permeating systems (COMPS), patented technology by IFRI were tested to determine the possibility of cross-contamination between the training aids, and the results conclude that there was not any evidence of cross-contamination observed during any of the trials.
208

Intérêts de la variabilité de l'alvéolyse humaine dans l'estimation de l'âge en anthropologie médico-légale / Interests of the variability of the human bone loss in the estimation of the age in forensic anthropology

Ruquet, Michel 29 March 2010 (has links)
L' étude réalisée s'est portée sur la détermination de l’âge à partir d’investigations sur l’alvéolyse humaine.Le manque de fiabilité de l’attache épithéliale comme indicateur d’âge et l’absence de corrélation de la translucidité dentinaire sur dents entières ou coupées ont démontré l'intérêt d'un nouveau modèle odontologique d'estimation de l'âge. Nous avons, pour cela, , recruté une série importante de scanners (500)à visée implantaire assortis d’un questionnaire médico-administratif administré en face à face. Une base équilibrée en terme de sex-ratio et de classes d’âge a été constituée avec comme critère d’inclusion des secteurs dentés et observables. La deuxième phase a consisté à pratiquer des mesures biométriques de la hauteur de perte d’os alvéolaire par rapport au référent classique que constitue la jonction émail Cément. A partir des données relevées, et ajustées sur les variables individuelles et comportementales recueillies dans le questionnaire, nous avons établi une corrélation avec la variable continue, l’âge. Nous avons pu proposer un modèle d’estimation de l’âge alternatif à celui de la méthode odontologique de Lamendin avec une fiabilité identique mais applicable sur des classes d’âges de 25 à 60 ans.Cette méthode a été validée par une étude comparative de trois indicateurs d'erreurs et la formule optimisée par la méthode Bootstrap. Les modèles ont été, ensuite, appliqués sur une série de crânes anciens complets (32) et sur une population contemporaine (50). Enfin, nous avons ouvert la perspective ,à partir du même protocole, d'estimation de l'alvéolyse à partir de l'âge ajusté ou non sur les différentes variables retenues dans l'étude principale. / The study carried out concerned to the determination of the age from investigations on the human alveolar bone loss. The lack of reliability of the tie epithelial as indicator of age and the absence of correlation of the transparency of the dentin on whole or cut teeth demonstrated the interest of a new odontological model of estimation of the age. We have, for it, recruited an important series of scanners (500) for implantological treatment matched by a medical administrative questionnaire administered opposite to face. A base balanced in term of sex-ratio and age groups was established with as criterion of inclusion of the toothed and observable sectors. The second phase consisted in practicing biometric measures of the height of loss of alveolar bone with regard to the classic referent that the junction enamel Cement establishes .From the data, and adjusted on the individual and behavioral variables collected in the questionnaire, we established a correlation with the continuous variable, the age. We were able to propose a model of estimation of the age in that of the odontological method of Lamendin with an identical but applicable reliability on age groups from 25 to 60 years. This method was validated by a comparative study of three indicators of errors and the formula optimized by the Bootstrap method. The models were, then, applied to a series of ancient complete skulls (32) and to a contemporary population (50). Finally, we opened the prospect, from the same protocol, from the estimation of the alveolar bone loss from the adjusted age or not on the various variables held) in the main study.
209

Qualitative Analysis for the Characterization and Discrimination of Printing Inks

Williamson, Rhett J 27 October 2016 (has links)
Improvements in printing technology and the wide accessibility of advanced printers has resulted in an increase in counterfeiting. Of particular interest to forensic document examiners, ink analysis of security documents has emerged as an important tool for the analysis, comparison, and association of inks to a potential production source. In this study, methods were developed for Py-GC/MS, ATR-FTIR, DART-MS, and MALDI-MS analyses of printing inks of four classes: 78 inkjet inks, 76 toners, 79 offset inks, and 86 intaglio inks in order to generate information on the organic chemical characterization of the inks to determine the ability to associate and discriminate the inks for uses in security document examinations. The suite of analytical techniques evaluated in the study focused on having the following analytical characteristics: 1) rapid analysis time, 2) little-to-no sample preparation, 3) minimal destructiveness to the sample, 4) allow for association of inks with the same source of origin as well as discrimination of inks originating from different sources. As a result of this study, a novel searchable library database of inks was developed for use with each analytical chemical method that allows for data fusion. Py-GC/MS analysis was used to achieve >63% discrimination of toner inks on the basis of the characterization of polymer degradation products. The combination of a protocol implementing first ATR-FTIR and subsequently DART-MS analysis resulted in >96% discrimination for toners, 95% for inkjet, >92% for offset, and >54% for intaglio. In addition, a case study was performed using DART-MS to illustrate its utility as a tool for ink analysis in document examination. The results of MALDI-MS analyses from two different instruments resulted in >90% discrimination of a subset of all inks by characterizing the colorant molecules present in ink formulations. A study characterizing luminescent compounds present in the formulation of inks in crossed-line intersections was performed using a combination of MALDI-MS, LC-MS, and TLC. Overall, it was shown that the combination of analytical techniques included within this dissertation can provide information on the organic chemical composition of four classes of printing inks, which is useful for the future of document examination.
210

Exoneration or Observation? Examining a Novel Difference Between Liars and Truth Tellers

Molinaro, Peter F 26 March 2015 (has links)
Individual cues to deception are subtle and often missed by lay people and law enforcement alike. Linguistic statement analysis remains a potentially useful way of overcoming individual diagnostic limitations (e.g. Criteria based Content Analysis; Steller & Köhnken, 1989; Reality monitoring; Johnson & Raye, 1981; Scientific Content Analysis; Sapir, 1996). Unfortunately many of these procedures are time-consuming, require in-depth training, as well as lack empirical support and/or external validity. The current dissertation develops a novel approach to statement veracity analysis that is simple to learn, easy to administer, theoretically sound, and empirically validated. Two strategies were proposed for detecting differences between liars' and truth-tellers' statements. Liars were hypothesized to strategically write statements with the goal of self-exoneration. Liars' statements were predicted to contain more first person pronouns and fewer third person pronouns. Truth-tellers were hypothesized to be motivated toward being informative and thus produce statements with fewer first person pronouns and more third person pronouns. Three studies were conducted to test this hypothesis. The first study explored the verbal patterns of exoneration and informativeness focused statements. The second study used a traditional theft paradigm to examine these verbal patterns in guilty liars and innocent truth tellers. In the third study to better match the context of a criminal investigation a cheating paradigm was used in which spontaneous lying was induced and written statements were taken. Support for the first person pronoun hypothesis was found. Limited support was found for the third person pronoun hypothesis. Results, implications, and future directions for the current research are discussed.

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