Currently, DNA profiling is the gold standard to identify an individual. However, determining body fluid origin is important in criminal investigations, offering additional information surrounding the circumstances of a crime. However, crime labs can only definitively identify blood and semen and presumptively saliva using techniques that consume time and sample and do not simultaneously identify all forensically relevant body fluids. This causes many crime labs to want to bypass body fluid identification altogether. Therefore, advances into more definitive molecular-based body fluid methods are necessary. One such technique is mRNA profiling because it provides a highly sensitive and specific approach to definitively identifying all relevant body fluids in parallel. Although advancements have been made, improvements to mRNA profiling methodologies still need to be researched such as 1) possible mRNA recovery from established DNA workflows and 2) possible integration of mRNA profiling into an upfront male DNA screening assay for triaging sexual-assault evidence likely to contain male DNA and reduce/eliminate a significant bottleneck in the standard DNA workflow of microscopic sperm identification. This study was designed to address these two issues by evaluating a novel way to recover RNA, for body fluid identification, from the waste fractions of a PrepFiler™ DNA extraction, and from the DNA extracts directly. Next, this study aimed to provide a relatively quick molecular-based approach for screening sexual-assault evidence. It involves extraction of RNA using the Dynabeads™ mRNA DIRECT™ Kit, while saving the extraction waste fractions for downstream male-DNA quantitation and STR profiling. The RNA is then used in a rapid and sensitive 1-step combined reverse transcription-HRM assay to positively detect the presence of sperm. Both non-conventional co-extraction methods successfully addressed current body fluid identification challenges and allowed for easy integration into existing workflows when single sourced, mixture and mock casework samples were analyzed.

Current methods in ignitable liquid identification and classification from fire debris rely on pattern recognition of ignitable liquids in total ion chromatograms, extracted ion profiles, and target compound comparisons, as described in American Standards for Testing and Materials E1618-10. The total ion spectra method takes advantage of the reproducibility among sample spectra from the same American Society for Testing and Materials class. It is a method that is independent of the chromatographic conditions that affect retention times of target compounds, thus aiding in the use of computer-based library searching techniques. The total ion spectrum was obtained by summing the ion intensities across all retention times. The total ion spectrum from multiple fire debris samples were combined for target factor analysis. Principal components analysis allowed the dimensions of the data matrix to be reduced prior to target factor analysis, and the number of principal components retained was based on the determination of rank by median absolute deviation. The latent variables were rotated to find new vectors (resultant vectors) that were the best possible match to spectra in a reference library of over 450 ignitable liquid spectra (test factors). The Pearson correlation between target factors and resultant vectors were used to rank the ignitable liquids in the library. Ignitable liquids with the highest correlation represented possible contributions to the sample. Posterior probabilities for the ASTM ignitable liquid classes were calculated based on the probability distribution function of the correlation values. The ASTM ignitable liquid class present in the sample set was identified based on the class with the highest posterior probability value. iv Tests included computer simulations of artificially generated total ion spectra from a combination of ignitable liquid and substrate spectra, as well as large scale burns in 20’x8’x8’ containers complete with furnishings and flooring. Computer simulations were performed for each ASTM ignitable liquid class across a range of parameters. Of the total number of total ion spectra in a data set, the percentage of samples containing an ignitable liquid was varied, as well as the percent of ignitable liquid contribution in a given total ion spectrum. Target factor analysis was them performed on the computer-generated sample set. The correlation values from target factor analysis were used to calculate posterior probabilities for each ASTM ignitable liquid class. Large scale burns were designed to test the detection capabilities of the chemometric approach to ignitable liquid detection under conditions similar to those of a structure fire. Burn conditions were controlled by adjusting the type and volume of ignitable liquid used, the fuel load, ventilation, and the elapsed time of the burn. Samples collected from the large scale burns were analyzed using passive headspace adsorption with activated charcoal strips and carbon disulfide desorption of volatiles for analysis using gas chromatography-mass spectrometry

The present study examined the decomposition of neonate pig samples (n = 42) in a freshwater pond located in Holliston, Massachusetts. They were individually placed either in a mesh bag (control group), a trash bag, or a backpack to determine whether trash bags or backpacks affected the rate of decomposition in a freshwater pond. Six pigs were present at each recovery period: two as control specimens, two placed in trash bags, and two placed in backpacks. The neonate pigs were assessed at seven different recovery periods: one week, two weeks, four weeks, twelve weeks, twenty-four weeks, thirty-five weeks, and forty-eight weeks. Throughout the study, decomposition was assessed using the scoring methods of Heaton et al. (2010) and Keough et al. (2017) along with photographs and written descriptions. It was hypothesized that the enclosed remains would decompose at a slower rate than the exposed remains; however, this was not the case. Due to scavenging, the trash bag specimens were removed from statistical analysis. Statistical analyses determined that there was not a statistically significant difference in the Total Body Scores (p = 0.511), the Total Aquatic Decomposition Scores (p = 0.635), and percent mass loss (p = 0.265) between the control groups and the backpack groups.

Bioarchaeologists work to reconstruct the past using skeletal remains inside a framework influenced by archaeological data. One area, into which bioarchaeologists have sought to provide insight, is the reconstruction of physical activities through skeletal indicators. These indicators of activity include looking at skeletal changes such as development of osteoarthritis, osteon remodeling, dental modifications, cross-sectional bone geometry (CSBG) and changes to muscle attachment sites, also known as entheseal changes. The study of entheseal changes has received much attention as researchers have hypothesized that a direct correlation between muscle use and entheseal size exists. Researchers sought to interpret specific movements such as spear-throwing or kayaking by examining the muscle attachment sites involved in those movements and analyzing the robusticity of the entheses. CSBG has also been used to analyze activity levels and interpret the degree of manual labor an individual was involved in. These analyses are based on the biomechanical interpretation of bone as structure that reacts to mechanical stress by increasing bone thickness. This research tested the hypothesis that changes to entheseal size in the humerus would correlate to changes in CSBG. Entheseal changes were analyzed using two methods, the Hawkey and Merbs (1995) and Mariotti et al. (2007) methods. Both methods were analyzed in terms of their ease of use and intraobserver error rates. The Mariotti et al. (2007) method of scoring entheseal changes was found to have more instances of a significant intraobserver error rate than the Hawkey and Merbs (1995) method despite the improved photographs and more detailed descriptions provided by the authors. Both entheseal scoring methods were used to analyze the correlation between entheseal changes and CSBG in the form of the polar moment of area (J) as standardized for size (J'). CSBG has been found to have stronger correlations with mechanical use and this research sought to identify relationships between entheseal development and J' in the humerus. Entheses scored using the Mariotti et al. (2007) method were more frequently found to have a significant correlation with CSBG, while only one enthesis scored using the Hawkey and Merbs (1995) method was found to have a significant correlation (p <.05) with CSBG. This implies that the method used greatly affects the identifiable correlations between entheseal changes and CSBG. Refined methods and more research are necessary before entheseal changes can be accurately used in activity reconstruction.

The ability to extract ignitable liquids from wooden fire debris samples is an important aspect of arson investigation. A common method by which the ignitable liquids are extracted is heated passive headspace extraction, a process by which a sample is heated in a sealed container and any ignitable liquid residues present desorb from the sample and adsorb to an adsorbent present in the container. An activated charcoal strip is most often used as the adsorbent, and the recommended extraction procedure is to allow the sample to extract in an oven set at a temperature between 50 °C and 80 °C for an amount of time between 8 and 24 hours. The ignitable liquid residues can then be eluted from the adsorbent and analyzed by gas chromatography-mass spectrometry (GC-MS) to identify the type of ignitable liquid present within the sample as well as specific compounds within the ignitable liquid. The extraction procedure typically does not yield 100% of the original amount of ignitable liquid deposited on the sample. Some of the ignitable liquid residue loss can be attributed to any irreversible adsorption that occurs between the substrate and the ignitable liquid. This irreversible adsorption is not known to be a constant across different wood genera; however, the extent of irreversible adsorption may vary between differing genera of wood. The focuses of this thesis are to examine any trends in irreversible adsorption that occur in wooden substrates, to see which genera of wood presents the greatest retention of ignitable liquids, and to see if any correlation exists between the retention capabilities of a wood genus and its density. The densities were determined for a total of thirteen common wood genera, which were spiked with one of three ignitable liquids and then subjected to heated passive headspace extraction. A semi-quantitative approach was taken by comparing the abundance of specific compounds within an ignitable liquid extracted from a wood substrate to the abundance present in a diluted sample of the same ignitable liquid, allowing a comparison between different genera to be made. Ultimately, it was determined that different genera of wood do display different retention capabilities for the common ignitable liquids examined in this thesis, but there was no genus of wood which consistently demonstrated a greater retention for the ignitable liquids compared to the other genera, nor was there a genus of wood which consistently allowed for greater recovery of the ignitable liquids compared to the other genera.

Ideally a DNA profile will have high Peak Heights (PHs), balanced Peak Height Ratios (PHRs) and no drop out. However, low template DNA (LTDNA) is limited in quantity, quality or both and LTDNA profiles do not always consistently provide interpretable signal. Post-Polymerase Chain Reaction (PCR) purification is an efficient enhancement method that can be utilized to increase the amount of information in a LTDNA profile without elevated stutter, which can be common with other enhancement methods. Post-PCR purification decreases the remaining components left over from amplification, such as deoxyribonucleotide triphosphates, primers, salts, and enzymes so there is less competition during the electrokinetic injection and more DNA will go into the capillary. When post-PCR purification is used; PH’s will increase, PHRs should remain stable before and after purification and may result in recovery of alleles that previously had dropped out. Allele recovery may be the difference between an inconclusive result and an inclusion or exclusion. The efficacy of Post-PCR purification was assessed by amplifying single source DNA with both ABI AMPFℓSTR® Identifiler® (template mass down to 0.0625 ng) and Identifiler® PLUS (template mass down to 0.03125 ng) and performing post-PCR purification with Qiagen® MinElute® and Macherey-Nagel NucleoSpin®. The original amplified product and purified product were analyzed and compared and it was determined post-PCR purification reduced the primer front, increased the PHs, recovered additional alleles and did not affect the PHRs. On average the Fold Increase (FI) for Identifiler® product purified with Qiagen® MinElute® is 3.5 and the average FI for Identifiler® PLUS product purified with Qiagen® MinElute® and Macherey-Nagel NucleoSpin® is 3.2. Additionally, the stutter percentage observed in the original sample profile was compared to the purified samples to determine if purification affected the stutter percentage of Identifiler® PLUS product. It was determined at only a few alleles the amplified product was above or below the stutter percentage of purified product. The stutter percentage values for purified samples were further compared to the Identifiler® PLUS manual and only one allele’s stutter percentage is above the companies stutter cut off values. Post-PCR purification with Qiagen® MinElute® or Macherey-Nagel NucleoSpin® is a successful enhancement method to increase information of a LTDNA profile without introducing additional complications that other enhancement methods are known to do.

Arson cases involve the collection and interpretation of a variety of evidence. Though some analysis such as the identification of accelerants has been heavily researched and tested, other areas have limited research and need to be addressed. The goal of this research is to assess the damage various fabric types face when exposed to high temperatures, open flames, and various chemicals. To answer this question I exposed polyester, cotton, nylon, spandex as well as polyurethane coated nylon and polyester to temperatures up to 300°C, open flame, gasoline, and bleach. The color, damage, and type of damage were assessed and reported. The synthetic fabric category showed considerable resistance to dye loss when exposed to the stimuli above and melted when exposed to high temperature and open flame. Cotton, a natural fiber, showed signs of color loss in all tests aside from gasoline exposure. Additionally, when exposed to high temperature and open flame, cotton would dehydrate, discolor, and char. To improve the assessment of fabrics in arson related cases it is necessary to create a uniform understanding of how various fabric and fibers respond to various exposures.

The research presented in this dissertation describes the design and synthesis of substitutional-solid-solution-based multivariate metal-organic frameworks (SSS-based MTV MOFs) with functionalized organic linkers to study their emergent properties in the crystalline solid state. The synthetic versatility and tunability of organic chemistry coupled with the predictable organization of inorganic structures enables MTV MOF systems to further the fundamental understanding of structure-composition-property relationships for the targeted design of applied materials due to their ability to control the structure, composition, and property independently. To begin, a set of terphenyl linkers with varied steric and electronic properties were crystallized as a family of UiO-type MOFs to assess their effects on the uptake and separation of noble gases. This series was then isoreticularly expanded to PEPEP linkers and combined in a PIZOF-type MTV MOF system to evaluate its capability as a multivariate platform for linkers with different functional groups. Chapters 4, 5, and 6 each focus on a different advantageous aspect of the PIZOF system, first exploring the free volume in the pores where covalently bound redox active mediators demonstrate electron diffusion via charge-hopping mechanics to achieve redox conductivity. The next chapter studies the aggregate-induced emission properties that can arise from link-link interactions due to the interpenetrated structure of PIZOF-type frameworks by incorporating a pentacene-based linker in an MTV MOF series to determine its singlet fission potential. The last chapter utilizes the water stability of the PIZOF framework to investigate how increasing pore hydrophilicity through the inclusion of a rationally designed pentaerythritol-containing linker affects the water adsorption. This dissertation demonstrates the value of the SSS-based MTV MOF approach under the paradigm of reticular chemistry to enable the design of tunable and complex solid-state systems with the ability to deconvolute structure from composition and property, while still allowing for relationships between the structure, composition, and property.

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No description available.