Master of Science

thesisWater column, sediment and pore water samples were collected from multiple locations of the Great Salt Lake (GSL), Utah to examine the spatial and temporal distribution of total mercury (THg) and methyl mercury (MeHg) concentrations and MeHg production potentials (MPPs). Sampling locations included multiple transects in the south arm of the GSL, adjacent freshwater influenced bays, and multiple impounded and sheet flow freshwater wetland sites during the period of summer 2009-summer 2012. Select water column and sediment subsamples were spiked with inorganic mercury (I204Hg) and methyl mercury (Me204Hg) to examine net production of methyl mercury (Me204Hg ) and net loss of Me201Hg. First order methylation (kmeth) and demethylation (kdemeth) rate constants were determined from changes in isotope dilution corrected concentrations and/or changes in isotope ratios as a function of time. Tin reducible inorganic Hg (Hg(II)R) was used as a proxy for bioavailable Hg(II) in GSL samples. MeHg production potentials (MPPs) were calculated as the time integrated product of kmeth and Hg(II)R to compare methylation in deep brine layer (DBL) versus underlying sediment slurry (SSL) samples of the GSL. A large range of methylation rate constants (1.4E-6 to 1.1E-3 hr-1) was observed across the region, whereas demethylation was only significant in the DBL. Positive correlation of kmeth to organic matter content was observed in sediment of the freshwater influenced bays and impounded wetlands, while this trend was not observed in DBL and SSL of the GSL. These results further indicate that sediment organic matter, as well as other factors (e.g., organic matter lability and sulfide concentrations) contribute to production of MeHg. Spatially, higher MeHg concentrations in the GSL and sheet flow freshwater wetlands present the possibility of ‘hot spots' for MeHg introduction into the food web. Greater and temporally constant MPPs in SSL relative to DBL may explain the persistence of high MeHg concentrations in the DBL

Doctor of Philosophy

dissertationOver the past decade, our research group has worked on developing surface-based immunoassays to detect disease biomarkers. Our immunoassay platforms use a gold surface coated with an N-hydroxysuccinimide (NHS)-based monolayer and a layer of antibodies to capture a target antigen. Readout is achieved by surface-enhanced Raman scattering (SERS) or giant magnetoresistance (GMR) after labeling of the captured antigen with Raman dye-modified gold nanoparticles or magnetic particles, which are also coated with antibodies. Both of these platforms enable the low-level detection of numerous biomarkers and have the potential for translation into a point-of-need (PON) (i.e., rapid, easy to use, and field deployable) test. As part of an effort to develop a PON test, this dissertation includes investigations of: (1) SERS-based detection of botulinum neurotoxins (BoNTs), (2) protein immobilization procedures, and (3) magnetic microcapsules (MMCs) for use with GMR detection. First, a SERS-based immunoassay for bioterrorism agents, botulinum neurotoxins A (BoNT-A) and B (BoNT-B) with picomolar (or lower) detection limits for BoNT-A and; BoNT-B in buffer and serum is described. These results not only demonstrate sufficient detection of these markers at levels important to homeland security and human health monitoring, but also the potential to translate this methodology to a PON test. Next, the reactivity of NHS ester-terminated monolayers, a common approach in protein immobilization chemistry, is investigated to assess the competition of the purported amidization reaction to that of hydrolysis. Results of kinetic studies on hydrolysis and aminolysis under relevant assay conditions show the rate of hydrolysis is 300× faster than that of aminolysis. These results indicate that it is highly unlikely that proteins are covalently linked to the surface and suggest that the protein layer is adsorbed via hydrophobic, hydrogen bonding, and electrostatic interactions. The last section examines the development of an MMC-based label. With marked improvement in both stability and magnetization over commercially-available magnetic nanoparticles, these MMCs show potential for the eventual enhanced function as a label in a GMR-based immunoassay. With these results, this dissertation aims to set the stage for the rational development of assays that will facilitate a paradigm shift towards PON tests

Doctor of Philosophy

dissertationThis qualitative study explored the relationship between mindfulness practice and social justice advocacy among psychotherapy practitioners. The increased call to include and re-vision social justice advocacy as a central component of practice in feminis

Doctor of Philosophy

dissertationIn this dissertation, I defend the thesis of comparability, understood as the claim that agents are always able to choose by taking one of three deliberative stances: regardless of what the choice options are, agents possess the capacity to prefer one option to another or to be indifferent between them. I will present an interpretation of utility theory to serve as an account of how agents might, as a practical matter, reason their way through any given choice situation. This economic account of choice is explicitly folk psychological insofar as the internal mental states of choosing agents play functional roles in it, though the descriptions of the mental states are intentionally parsimonious. The economic account given therefore steers a course between competing theoretical extremes: revealed-preference theory, which is meant to account for choice without appealing to internal mental states, and value accounts of choice, which attempt to detail the internal mental workings that give rise to agent preferences. In the account I favor, the notion of preference is regarded as a theoretical primitive and value can be understood as a derived concept. Many objections to comparability arise from the assumption that value judgements are necessary in order to compare; I show how such objections are answered if value is understood as being derived from preference instead of vice-versa. Eliminating value as a theoretical necessity for choice does not counter all incomparabilist objections. I provide a response to one of the most trenchant remaining objections, the small improvement argument, which seems to show that any trimodal theory of choice, whether it assumes values are necessary in order to choose or not, can lead to self-defeating choices, and therefore fails as an account of rational choice. I show that the small improvement argument can be answered without abandoning the assumption of comparability. Finally, I consider the constitutive objection to comparability, and note that while it cannot establish that comparability must fail, it does, when understood as a subjective objection, suggest that in addition to having the capacity to compare any two options, agents also possess the capacity to refuse to compare them

Master of Science

thesisThis research introduces a new process to fabricate polymer nanocomposite materials reinforced with an ultra-high weight fraction of aligned carbon nanotubes (CNTs). This process is based on ultrasound directed self-assembly, which employs the force associated with a standing ultrasound wave to concentrate and align the carbon nanotubes in a user-specified pattern. In contrast with existing processes, which typically limit fabricating nanocomposite materials with a CNT weight fraction on the order of 1 weight percent (wt.%), polymer nanocomposite materials were fabricated to contain a weight fraction of aligned CNTs in excess of 10 wt. %. The fabrication process, dispersion of CNTs in the polymer matrix, appropriate acoustic wave propagation velocity in the matrix material, and degradation of polymer mechanical properties from exposure to ultrasound stimulation are described. The mechanical properties of these polymer nanocomposite specimens were experimentally measured and it was found that the ultrasound alignment process resulted in specimens that displayed a significant increase in ultimate tensile strength, Young’s modulus, and moduli of resilience and toughness, compared to specimens including polymer nanocomposite materials with randomly oriented CNTs, and “processed polymerâ€. The research demonstrates that by combining ultrasound alignment with microwave radiation exposure, the Young’s modulus and ultimate tensile strength of the polymer nanocomposite material is further enhanced. Specimens were affected differently by microwave radiation exposure, depending on the type of alignment and dispersion used to create the specimen. These observations may guide further optimization of the process

Master of Science

thesisMagnetic separation technology has been utilized for many years in the scrap sorting industry. Ferrous metal scrap is easily sorted using magnetic separation while sorting nonferrous scrap is a tricky process. Currently available technology to sort nonferrous material using mechanical eddy current sorters have limitations in terms of the capability to sort material larger than a quarter inch. Moving parts are subjected to wear and tear and they are also incapable of sorting different nonferrous metals and alloys like aluminum, aluminum alloys, copper, copper alloys, titanium, and so forth, from one another. The research work presented in this thesis reveals various nonferrous metals and alloy sorting test results using solid state, variable-frequency eddy current technology. The setup for this technology consists of a ferrite core with a V-shaped cut for the air gap wound with wire to produce an alternating magnetic field in the gap when supplied with alternating current. Nonferrous particles, when fed into the gap, interact with the external magnetic field which induces eddy currents into the material, and based on Lenz’s law, material tends to deflect away from the source of external magnetic field. Frequency determination for the selective sorting of material from the mixture of nonferrous material was done based on the ejection velocity experiments performed on size, ranging 4mm to 12mm at a frequency range of 1kHz - 8 kHz on aluminum, copper, brass, and titanium. Ejection velocity results were used to determine an optimal strategy and sorting experiments of nonferrous metals and alloy mixtures were conducted using a double stacked core of ferrite material having a 2mm inner gap and 33 mm outer gap. Also, experiments were conducted to sort zorba scrap using a larger size NiZn ferrite core with a 10mm inner gap and 20 mm outer gap. The pendulum experiment showed a trend of increasing ejection velocity with respect to increasing frequency, but the magnitude of velocity for different materials differ at a particular frequency is not the same, this allowed for an optimal frequency to be determined for optimal sorting. Nonferrous materials were sorted very well using both single and double stacked ferrite cores, but grade and recovery was slightly better when the double core was used. Promising results were also achieved for aluminum alloy sorting. All the results strongly indicate that capability for the solid state eddy current sorting technique is to be used to sort various nonferrous metals and alloys when operated at the optimal frequency

Master of Science

thesisMedia-related technology can capture attention, leaving the user depleted of attentional resources. However, the theory of attention restoration (ART) suggests that environments with certain qualities can restore previously depleted resources. Previous research has tested ART using a variety of behavioral and perceptual tasks; however, researchers have yet to examine the predictions of ART using neurophysiological methods. I hypothesize that the default mode network, a region associated with internal thoughts, is associated with the restoration process in nature. This exploratory study evaluated the process of restoration using electroencephalography to measure potential changes in oscillatory activity after participants were exposed to a natural environment. Forty-seven (19 males) participants 18 to 37 years in age were recruited from the Salt Lake City area via flyers, advertisements, and word of mouth. In order to assess the effects of technological distraction, participants were assigned to a group that was concurrently talking on a phone during the walk or to a group that did not have any technology with them. Participants in the phone group had decreased recognition memory and increased activity at the theta frequency after the walk compared to participants who went on the walk without their phone. The data indicate that technology disrupts the process of restoration and decreases awareness of the surroundings

Master of Science

thesisThis thesis work mainly evaluates methods of obtaining pure titanium hydride from different sources and methods and its theoretical and experimental kinetics using model formulation. The first route was to use Direct Reduction of Titanium Slag (DRTS) in which metallic titanium can be obtained by dehydrogenation of titanium hydride after impurities are removed. The leaching characteristics of iron removal from the reduced upgraded titanium slag was studied with mild hydrochloric and boric acids under ambient pressure and elevated pressure. Under the constraint that 1% (w/w) of titanium hydride loss is the maximum amount tolerable, 0.1 M hydrochloric acid at 140 °C was found to be the most effective condition for iron removal (87.63%). A factorial design of experiment for equation modeling with three main factors (temperature, concentration of hydrochloric, and boric acids) was performed and associated modeling results were in good agreement with experimental data. Additional study was carried out to justify the assumption, which utilized the evaluation of the effects of three empirical size distributions, the Gate-Gaudin-Schuhmann distribution, the Rosin-Rammler-Bennett distribution, and the Gamma distribution, on the fluid-solid reaction kinetics. The expressions for overall conversion rate of entire particle assemblages were derived mathematically, and calculated by a technical computing language, “MATLABâ€. According to the calculation, the assumption that particle size is uniform can be valid in the determination of fluid-solid kinetics in the case where the coefficient of variation (CV) is less than 0.5. Based on the theoretical kinetic study for the effect of particle size distribution, it was assumed that the effect of particle size distribution of reduced upgraded titanium slag (UGS) does not have to be considered in the calculation of kinetics. Based on this calculation, a rate-controlling process can be found and it seems to follow interfacial reaction controlled kinetics. The activation energy of the reaction was determined to be 73.9 kJ/mole. Also, the other mechanism of the reaction-controlling process (solid-state diffusion) is suggested. An additional way of obtaining pure titanium involves the extraction of titanium from ilmenite using tannic acid. The experimental and modeling results showed the feasibility of the new process to obtain titanium

Doctor of Philosophy

dissertationWith the steady increase in online shopping, more and more consumers are resorting to Product Search Engines and shopping sites such as Yahoo! Shopping, Google Product Search, and Bing Shopping as their first stop for purchasing goods online. These sites act as intermediaries between shoppers and merchants to drive user experience by enabling faceted search, comparison of products based on their specifications, and ranking of products based on their attributes. The success of these systems heavily relies on the variety and quality of the products that they present to users. In that sense, product catalogs are to online shopping what the Web index is to Web search. Therefore, comprehensive product catalogs are fundamental to the success of Product Search Engines. Given the large number of products and categories, and the speed at which they are released to the market, constructing and keeping catalogs up-to-date becomes a challenging task, calling for the need of automated techniques that do not rely on human intervention. The main goal of this dissertation is to automatically construct catalogs for product search engines. To achieve this goal, the following problems must be addressed by these search engines: (i) product synthesis-creation of product instances that conform with the catalog schema; (ii) product discovery- derivation of product instances for products whose schemata are not present in the catalog; (iii) schema synthesis- construction of schemata for new product categories. We propose an end-to-end framework that automates, to a great extent, these tasks. We present a detailed experimental evaluation using real data sets which shows that our framework is effective, scaling to a large number of products and categories, and resilient to noise that is inherent in Web data

Clinical utility of multigene versus single gene genomic profiling in metastatic colorectal cancer

dissertationRoutine KRAS mutations testing in metastatic colorectal cancer (CRC) patients to guide anti-EGFR-targeted therapy use is recommended by clinical guidelines. CRC patients may have mutations in other KRAS sites not routinely tested, and in other potentially chemotherapy targetable genes. Multigene genomic profiling can identify mutations at a relatively reasonable cost, but its clinical utility has never been reported. This research’s goal was to compare clinical utility measures of multigene genomic profiling in metastatic CRC patients to measures associated with KRAS single gene testing. The research hypothesis was higher clinical utility associated with multigene genomic profiling, leading to more appropriate use of targeted therapies, more clinical trial enrollment, and improved survival compared to KRAS single gene testing. An observational study of genomically-tested adult metastatic CRC patients who were alive between 06/01/2008-01/20/2016 and treated at the Huntsman Cancer Institute (HCI) was conducted. A comprehensive database was created combining data from HCI tumor registry, ARUP laboratories, UUHC EDW, and Oncore database. Index date was metastatic CRC diagnosis date. First, a cross-sectional study classified mutations detected by multigene genomic profiling into: actionable, potentially actionable, and nonactionable at patient and mutation level. Then, a retrospective cohort study compared treatment decisions and overall survival of multigene genomically profiled patients to those tested with KRAS single gene testing only. Baseline clinical and tumor characteristics were compared and included in regression analyses. Of 2,351 patients identified in the colorectal cohort, only 474 met eligibility criteria: 162 patients had KRAS single gene testing and 312 had multigene genomic profiling. Multigene genomic profiling identified multiple mutations of unknown significance that cannot guide evidence-based treatment decisions. However, the majority of patients had at least 1 mutation that offered potential investigational treatment options. Compared to KRAS single gene testing, multigene genomic profiling was not associated with more appropriate use of targeted therapy or overall survival difference, but was associated with significant increase in clinical trial enrollment. In conclusion, the value of this additional genetic information is still questionable. While multigene genomic profiling offers more trial enrollment and may inform future treatment decisions, currently multigene genomic profiling is not resulting in improved outcomes in metastatic CRC patients