VictorJuiz/thesis huggingface dataset:
Characterization of Natural Organic Matter in Bentonite Clays and Clay-rich Sediments

Natural organic matter (NOM) was characterized in clays that are being considered for a used nuclear fuel sequestration concept and in clay-rich subsurface Arctic sediments. Molecular-level techniques including biomarker analysis and nuclear magnetic resonance spectroscopy were employed to gain insight into NOM chemistry. Plant waxes were identified as the main input to NOM in these samples. NOM in all samples was in an advanced state of digenesis based on several calculated degradation ratios. The compounds detected in bentonite clays are hypothesized to be mainly recalcitrant and unlikely to act as a microbial substrate. One of the Arctic sediments contained more labile material and evidence of active microbes while NOM detected in the other two Arctic sediments is hypothesized to be mainly recalcitrant. These results suggest that NOM in these samples is primarily refractory and unlikely to undergo further diagenesis. The biogeochemical stability of refractory NOM requires further study.

Keywords: Arctic
Biomarker
Clay
Natural organic matter
Nuclear magnetic resonance spectroscopy
Nuclear waste
Advisor: Simpson, J. Myrna
An Integrated Approach to Estimate Pedestrian Exposure to Roadside Vehicle Pollutants

At many urban intersections, pedestrians and vehicles share the same space, where interactions between pedestrians and vehicles may hinder vehicle turning movements. This changes the amount of emissions generated by the vehicles, to which the pedestrians are exposed. This research investigates the pedestrian-vehicle interaction at the intersection of St. George Street and College Street in downtown Toronto. A microscopic vehicle simulation is integrated with a microscopic pedestrian simulation. Emission generation and dispersion are modelled to obtain concentration maps for emitted pollutants. The spatial-temporal data of the pedestrians are then integrated into these concentration maps to calculate pedestrian exposure to vehicle pollutants. Lastly, this framework is applied to test the effects of implementing a scramble signalling system at the intersection of St. George Street and College Street. It is found that the implementation of a scramble phase would increase exposure to Nitrogen Oxides and decrease exposure to Carbon Monoxide.

Keywords: Dispersion
Emission
Exposure
Pedestrian
Simulation
Transportation
Advisor: Roorda, J Matthew
Validation of the Evidence-based Practice Confidence (EPIC) Scale among Occupational Therapists

The objective of this study was to examine the reliability, floor and ceiling effects and construct validity of the evidence-based practice confidence (EPIC) scale among occupational therapists (OTs). A repeated measures study involving a baseline and a follow-up mail survey was conducted. One hundred and twenty-six OTs completed the baseline EPIC scale and construct validity questionnaire and 79 completed the scale at retest. Test-retest reliability, estimated using the intraclass correlation coefficient (ICC), was 0.92 (95% confidence interval (CI), 0.88-0.95). The minimal detectible change at the 95% confidence level (MDC

Keywords: evaluation studies
evidence-based practice
occupational therapy
reliability
self-efficacy
validity
Advisor: Salbach, M Nancy
Efficient Fourier Transformation of Unstructured Meshes and Application to MRI Simulation

This thesis demonstrates different ways to compute the MRI signal in finite element magnetic resonance imaging or FE-MRI. For linear elements the MRI signal can be found analytically. The error metric for linear elements to calculate the signal with a fixed error in k-space using an adaptive Gaussian quadrature is derived using finite element function derivatives and is then extended for use in quadratic elements. The feasibility of using the numerical steepest descent (NSD) method, which is designed to compute oscillatory integrals like the MRI signal equation, was also studied. The method was found to compute the MRI signal faster than adaptive Gauss quadrature for quadratic surface elements using typical MRI imaging parameters. The feasibility of NSD is discussed for volumetric quadratic elements and for different mesh geometries.

Keywords: Finite element analysis
Gaussian quadrature
MRI
Oscillatory integrals
Unstructured meshes
Advisor: Steinman, A David
Designing a Game-based Cognitive Assessment for a Tablet

The growth of ageing populations in many countries has prompted interest in the assessment of cognitive ability in elderly individuals. The early detection of cognitive impairment, and decline of cognitive abilities, is relevant to the diagnosis of mental health conditions such as dementia, mild cognitive impairment, and delirium. The detection and monitoring of cognitive status is contingent on the tools available and current methods are non-comprehensive and difficult to use.This thesis presents the design of a prototype to address the lack of readily available cognitive assessments for the elderly. The developed prototype is a tablet-based game designed for use in a clinical setting. A usability study was conducted to assess the prototype and based on these findings; a set of recommendations were developed. The limitations and implications for future work on this topic are outlined.

Advisor: Chignell, H Mark
Catalytic Conversion of Biomass for the Production of Hydrogen; Decomposition of Formic Acid

Highly active bimetallic catalysts were synthesized and used for the decomposition of formic acid for the production of hydrogen. Ruthenium alloys were prepared and resulted in a maximum formic acid conversion of 68% (after one hour at 180 °C) and a turnover frequency of 0.7/s (at 5 wt% formic acid). The most promising catalysts were characterized by the means of X-ray diffraction and scanning electron microscopy. Kinetic studies were also carried out over these catalysts for the determination of reaction rate and turnover frequency. Promotion of Ru/C with tin, barium and cesium increased the formic acid conversion by 55%, 18% and 11% respectively.

Advisor: Farnood, Ramin
Kriged Kalman Filtering for Predicting the Wildfire Temperature Evolution

Existing wildfire evolution models have been mostly developed in a deterministic modelling framework. As a complementary alternative, this thesis presents a stochastic framework based on the Kriged Kalman filter to obtain global temperature predictions given local temperature measurements. By solving the heat transfer partial differential equation driving the wildfire evolution, it is shown that the spatio-temporal mean temperature process associated with a wildfire evolving in a finite spatial domain under certain prescribed conditions can be approximated by a Fourier series. The potential of the proposed Kriged Kalman filtering framework in predicting the wildfire temperature evolution is demonstrated in simulations on temperature data generated by a simplified physical wildfire propagation model. The performance of the Kriged Kalman filter in predicting the wildfire temperature evolution is compared to that of standard Gaussian process regression.

Keywords: Kalman filtering
Kriging
mapping of spatio temporal processes
wildfire temperature modelling
Advisor: Liu, H.T. Hugh
Beyond the Pain: An Occupational Perspective on Knee Osteoarthritis

Total knee replacement (TKR) is an increasingly common surgery among individuals with osteoarthritis (OA). The outcomes of this surgery are positive; yet, many individuals do not fully resume their pre-TKR occupations. Literature is limited to describing the activity changes that occur but does not investigate the significance of those changes. A secondary analysis of eight purposively extracted transcripts from a primary study examining engagement in instrumental activities of daily living and personal and social roles among people with OA scheduled for surgery was conducted. A thematic analysis approach was used to examine the pre-TKR experiences of these individuals from an occupational perspective. Three themes were identified: (1) living with OA: it is more than just the knee, (2) gradually losing my occupational identity, and (3) losing too much--a "tipping point." The findings suggest that the significance of occupational changes are unique across individuals and affect their decision for surgery.

Keywords: Knee replacement
Occupational perspective
Occupations
Osteoarthritis
Secondary analysis
Thematic analysis
Advisor: Polatajko, Helene
If a Tree Falls in the Urban Forest: Current and Future Pest Vulnerability in Toronto's Urban Forest

Urban forests represent a valuable resource for cities. Accounting for species diversity and vulnerability to pests when managing an urban forest can help enhance services delivered and minimize management expenses. In this research, tree genera currently prevalent and commonly planted in Toronto were analyzed using a pest vulnerability matrix to explore how the city's urban forest's pest vulnerability may be changing. Current tree species composition was derived from inventory data, while the planting trends of a variety of local actors were determined through surveys and interviews. Results suggest some genera show clumped distributions and occasionally surpass recommended diversity thresholds in a given district or citywide. On-going planting behaviours in Toronto are replicating some current diversity issues while also increasing less common species. As a result, Toronto's vulnerability to tree pests and diseases will likely decrease, but certain serious issues will continue.

Keywords: pest vulnerability
planting trends
species composition
Toronto
tree pests
urban forests
Advisor: Conway, Tenley
The Thermal Design and Analysis of the CanX-4/-5 and NEMO-AM Nanosatellites

The main appeal of small satellites is that they are capable of fulfilling many of the same tasks as larger satellites, with lower development and launch costs. However, their smaller size can impose limitations on many of their systems, including their thermal control systems, which are often required to be passive and simple. This work summarizes the design and analysis of the thermal control systems for two small satellite missions, CanX-4/-5 and NEMO-AM. The development of a finite-difference thermal model using a commercial software package is described, followed by an overview of the analysis performed and the thermal control strategies employed in the satellites. The final analysis predictions show that the satellite temperatures for both missions were maintained within their required limits.

Keywords: nanosatellites
passive thermal control
small satellites
thermal control
Advisor: Zee, E Robert
Sunlit Leaf Photosynthesis Rate Correlates Best with Chlorophyll Fluorescence of Terrestrial Ecosystems

This thesis attempts to link carbon assimilation micro-processes to macro-scale chlorophyll fluorescence measurements. The Boreal Ecosystem Productivity Simulator (BEPS), a process-based model, is adopted to simulate the hourly global-scale gross primary productivity (GPP) in 2010. The total GPP is stratified into sunlit and shaded GPP using a two-leaf scaling approach. Concurrently, the usefulness of solar-induced chlorophyll fluorescence as a proxy of GPP is also assessed. Relatively precise global monitoring of fluorescence is made possible with a new retrieval method applied to GOME-2 observations. Linear correlation analysis is used to examine the monthly spatio-temporal patterns between GPP and fluorescence. The hypothesis that sunlit GPP is better correlated with fluorescence than total or shaded GPP has been successfully tested with GOME-2 data and BEPS results. Since shaded GPP is about 40% of the total GPP globally, this result points to a limitation of using fluorescence as a proxy of the total GPP.

Keywords: BEPS
chlorophyll fluorescence
ecological modelling
GPP
Advisor: Chen, M Jing
Is Diet Correlated with Feeding Morphology in Neotropical Suckermouth Armoured Catfishes (Siluriformes: Loricariidae)?

The suckermouth armoured catfishes (Siluriformes: Loricariidae) are a diverse group of predominantly detritivorous fishes inhabiting rivers of South and Central America. Their distinct jaws are specialized for scraping a wide range of substrate. Though it is hypothesized that specialization of loricariid feeding morphology may have played a role in their diversification, little is known about the ecological and evolutionary processes involved. The present study quantifies variation in jaw functional traits and body morphology in a phylogenetic context. Morphological variation was compared to species' relative position in assemblage isotope space (for both δ13C and δ15N) to test for correlations between diet and feeding morphology. Results show that although jaw functional traits are decoupled from body morphology, both are correlated with δ13C values. Partitioning of terrestrial and aquatic resources can be explained by both jaw functional traits and body morphology, however further partitioning of diet is only attributed to the former.

Advisor: Lopez-Fernandez, Hernan
Brain Signal Complexity and Creative Ability in Bilingual and Monolingual Children

Childhood bilingualism has long been associated with enhanced creative performance. The neural mechanisms underlying this phenomenon, however, have yet to be characterized. Research suggests bilingualism modifies neural networks for executive control. Such changes, which can be assessed with estimation of neural signal complexity, are thought to increase information processing capacity. We thus compared electroencephalographic signal complexity during a Go/No-Go task in bilingual and monolingual children aged 4 to 6, and correlated these complexity estimates with creative ability. Differences in EEG complexity were found in left centro-parietal and right frontal scalp regions. Complexity, however, did not correlate with children's creative performance scores. Although our findings failed to explain the neural link between bilingualism and enhanced creativity, we did find evidence to support the notion that bilingualism during early childhood is associated with functional brain changes in areas related to executive functioning.

Keywords: Bilingualism
Creativity
Development
Executive function
Neural Complexity
Advisor: Moreno, Sylvain
Timing Skew Calibration for Time Interleaved Analog to Digital Converters

This thesis presents a novel background timing skew calibration method used to improve the dynamic performance of time-interleaved analog-to-digital converters. A prototype 10GS/s 8bit 80-way time-interleaved SAR ADC was designed and fabricated in 65nm CMOS to illustrate this concept. The performance of a subset 5GS/s ADC is reported due to inadequate delay buffer range. After calibration, the 5GS/s ADC achieves an SNDR of 33.3dB at Nyquist and consumes 138.6mW from a 1V supply, yielding an FOM of 738fJ/conv-step.

Keywords: ADC
Calibration
SAR
Time-Interleaved
Timing Skew
Advisor: Carusone, Anthony Chan
Construction of FcHyd5p Variants to Assess the Potential of These Class II Hydrophobins as Molecular Tools for Surface Modification

Hydrophobins represent an attractive surface modification technology that can be paired with a variety of fusion partners to increase their versatility. Surface modification is a technique widely used to influence the adhesion of molecules to surfaces. The aim of this project is to assess the potential of the class II HFB FcHyd5p from Fusarium culmorum as a surface modification technique. FcHyd5p variants bearing RGD with two different linker sequences were engineered. Proteins were expressed in Pichia pastoris and purified using fast protein liquid chromatography (FPLC) and affinity chromatography. Bis-Tris-SDS-PAGE confirmed that native and fusion proteins were successfully produced and purified, with yields of the fusion constructs exceeding that of the native. Water contact angle demonstrated that RGD-FcHyd5p constructs could convert surface wettability of siliconized glass. Quartz crystal microbalance with dissipation (QCM-D) quantified HFB adsorption and assessed the effect of the presentation of RGD through different linkers on cell adhesion.

Keywords: Cell Adhesion
Hydrophobin
Hydrophobin Production
Hydrophobin Purification
Surface Modification
Advisor: Master, R Emma
Investigations of the Functional Expression of SLC6A14 in Non-CF and CF Airway Epithelial Cells

Recent studies have found single nucleotide polymorphisms significantly associated with more severe cystic fibrosis (CF) in the promoter region of the SLC6A14 gene, encoding a NaCl-dependent neutral and cationic amino acid transporter highly expressed in the lung. In a CF human bronchial epithelial cell line (CFBE41o-) transfected with wild-type- (CFBEwt) or dF505-CFTR (CFBEdf), 3H-arginine uptake followed Michaelis-Menten kinetics (CFBEwt Kt=95.01±14.05, CFBEdf Kt=72.8±16.14). Competitive inhibition experiments demonstrated function attributable to SLC6A14 and cationic amino acid transporter system y+ in both cells. Intracellular and transepithelial transport of 3H-arginine in non-CF and CF primary human airway cells was significantly reduced (~50%) in 0 Na+ or presence of a SLC6A14 blocker, alpha-methyl-DL-tryptophan (alpha-MT) apically, indicative of SLC6A14. There was no difference in SLC6A14 function between CF and non-CF cells, or CFBEwt and CFBEdf cells. These protocols allow isolation of SLC6A14 function in airway cells by competitive inhibition, Na+ dependence, and alpha -MT sensitivity.

Keywords: amino acid transport
cystic fibrosis
epithelial physiology
SLC6A14
Advisor: Gonska, Tanja
Household Indebtedness and Socio-Spatial Polarization among Immigrant and Visible Minority Neighbourhoods in Canada's Global Cities

Two key attributes of contemporary global capitalism are on the one hand, financialization and rising household indebtedness, and on the other, high levels of mobility and migration between nations, particularly into the `global' cities. Studies on household debt as it relates to race and immigrant status are scarce outside of the US. This thesis investigates levels and types of household indebtedness at the neighbourhood scale among immigrant communities and areas containing more racialized people, in the three largest Canadian cities - Toronto, Montreal, and Vancouver (TMV). In particular, it seeks to understand whether racialized and immigrant neighbourhoods experience higher and more onerous kinds of debt (such as unsecured forms of consumer debt) than other neighbourhoods, and the contours of any correlations between them. Descriptive statistics and regression models demonstrate that neighbourhoods housing immigrant groups, and certain visible minority groups, relate to higher levels of unsecured consumer debts in TMV.

Keywords: Debt
Housing
Immigration
Neighbourhoods
Political Economy
Race
Advisor: Walks, Alan
Investigating the Function of GTF2I and its Contribution to the Williams-Beuren Syndrome Neurological Profile

Williams-Beuren Syndrome (WBS) is a genetic neurodevelopmental disorder caused by the deletion of 25 protein-coding genes at chromosome 7q11.23. It is associated with a highly penetrant constellation of phenotypes, including aortic stenoses, characteristic facial features, and unique cognitive and behaviour profiles. I hypothesize that the gene GTF2I, a putative transcription factor, plays a role in signaling pathways that affect neuronal function and contribute to the WBS neurological profile. Genome-wide expression analysis of WBS patient-derived induced pluripotent stem cells and cortical neurons isolated from mice with a duplication or deletion of Gtf2i identified moderate changes in the expression of a few genes. Additionally, affinity purification and tandem mass spectrometry of GFP-tagged GTF2I validated a previously identified interaction with ZMYM3, a candidate for X-linked intellectual disability. Future studies to determine the consequence of this interaction in the brain will assist in characterizing GTF2I function in neurons and its contribution to WBS phenotypes.

Keywords: 7q11.23
GTF2I
iPSC
neurogenesis
WBS
Williams
Advisor: Osborne, R Lucy
Development of Self-assembled Amphiphilic Oligo-urethanes as Cardiovascular Drug Delivery Platforms

Current drug-coated balloon (DCB) technologies, used to prevent percutaneous coronary intervention-related restenosis via antiproliferative agent delivery to arterial lesions, are associated with systemic drug loss during catheter tracking and inefficient drug delivery to target tissues. This thesis aimed to study and synthesize novel amphilphilic oligo-urethanes (AOUs) as DCB drug carriers comprised of polyol, lysine diisocyanate and perfluoro-alcohol (PFA) segments to enhance drug release, binding and shielding against premature release respectively. AOU syntheses employing di-hydroxyl polyols were found to be susceptible to pre-polymer intramolecular cyclization, which prevented PFA conjugation. Such undesired cyclization reactions were circumvented in this thesis via the use of a mono-functional polyol to yield AOU analogues that were water soluble (≥430 mg/mL solubility) and relatively phase mixed. Fluorocarbon groups migrated to the surfaces of analogue films, yielding water contact angle values ≤51o. Preliminary analogue-cell compatibility studies and capillary electrophoresis-mediated drug-AOU dissociation assessments were conducted and are reported.

Keywords: Drug delivery
Restenosis
Oligo-urethanes
Advisor: Santerre, J. Paul
Assessing Pubertal Timing and Dynamics in a Large Longitudinal Sample of Adolescent Males

Pubertal timing and dynamics play an important role in physical and psychological development. This thesis describes three height-based indices that can be used to assess pubertal timing, and a measure of average exposure to testosterone derived from testosterone trajectories to assess pubertal dynamics. These parameters are derived in a sample of 500 male adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC). The indices of pubertal timing are shown to correlate with one another in ALSPAC. In a separate cross-sectional study, we show the association between one index and both testosterone levels and self-reported pubertal stage. The measure of average exposure to testosterone characterizes the timing and the magnitude of the rise in participants&rsquo; testosterone levels during adolescence. Future investigations may employ the methods outlined to account for timing and dynamics of puberty in relation to adolescent development.

Keywords: Neuroscience
Testosterone
Male
Adolescence
Pubertal Timing
ALSPAC
Magnetic Resonance Imaging
White Matter
Advisor: Paus, Tomas
Regulation of Kisspeptin-expressing Neurons and Stimulatory Mode of Action of Kisspeptin in Immortalized Hypothalamic Cell Models

Fertility is a highly regulated process dependent on the orchestration of hypothalamic neuropeptides and peripheral hormones, which converge on GnRH neurons in the HPG axis. Kisspeptin and its receptor, Gpr54 have emerged as fundamental gatekeepers of reproduction, acting upstream of GnRH neurons. Kiss neurons have been found to express estrogen receptors, Gpr54 and the GnIH receptor, Gpr147. We have generated immortalized, murine hypothalamic cell lines to investigate mechanisms of gene transcription in kisspeptin-expressing neuronal cell models. We show using qRT-PCR and western blot analyses that kisspeptin-expressing neuronal models are targets for gonadal steroids and hypothalamic neuropeptides. Further, using a novel GnRH-secreting cell line, we report that GnRH neurons expressing Gpr54 and Gpr47 are stimulated by kisspeptin, although suppressed by a kisspeptin/GnIH cotreatnent. Overall, these studies expand our knowledge of the regulation of Kiss neurons by estradiol, kisspeptin and GnIH, improving our understanding of kisspeptin as a modulator of GnRH neurons.

Keywords: Kisspeptin
Hypothalamus
Neuron
GnRH
Estradiol
GnIH
Neuropeptide
Advisor: Belsham, Denise