VictorJuiz/thesis huggingface dataset:
Molecular Genetic Insights into the Dimorphic Fungal Pathogen Blastomyces dermatitidis

The epidemiology of blastomycosis remains poorly understood in part due to the lack of a robust and discriminatory strain typing method for Blastomyces dermatitidis. Here we describe the development of a multilocus sequence (MLST) method to study the genetic variation and population structure of B. dermatitidis. Eighty geographically diverse clinical and environmental isolates were examined. Thirty-six unique sequence types were identified. With a discriminatory index of 91.4%, MLST identifies significant genetic diversity for the characterization of local and global B. dermatitidis isolates. To test whether this fungus represented a single species throughout its geographic range we performed phylogenetic analyses, applying Genealogical Concordance Phylogenetic Species Recognition (GCPSR). Phylogenetic analysis revealed two distinct clades, with five of the eight gene phylogenies studied supporting the separation of these lineages, which were also geographically partitioned. Based on fulfillment of GCPSR, we propose the current species B. dermatitidis harbors two genetically distinct non-interbreeding phylogenetic species.

Keywords: Blastomyces dermatitidis
blastomycosis
multilocus sequence typing (MLST)
Phylogenetic Species Recognition (PSR)
Genealogical Concordance Phylogenetic Species Recognition (GCPSR)
strain typing
Advisor: Low, Donald E.
Richardson, Susan
Regulation of Placental Autophagy by the Bcl-2 Family Proteins Myeloid Cell Leukemia Factor 1 (Mcl-1) and Matador/Bcl-2 Related Ovarian Killer (Mtd/Bok)

The process of autophagy is defined as the degradation of cellular cytoplasmic constituents via a lysosomal pathway. Herein I sought to examine the regulation of autophagy in the placental pathologies preeclampsia (PE) and intrauterine growth restriction (IUGR). I hypothesized that the Bcl-2 family proteins Mcl-1L and MtdL regulate placental autophagy and contribute towards dysregulated autophagy in PE. My results demonstrate that Mcl-1L acts to repress autophagy via a Beclin 1 interaction, while MtdL induces autophagy when it interacts with Mcl-1L. My data indicate that while autophagy is elevated in PE, a pathology characterized by oxidative stress, it is decreased in IUGR, a hypoxic pathology. Treatment with sodium nitroprusside to mimic PE caused a decrease in Mcl-1L and an increase in MtdL levels in response to oxidative stress, thereby inducing autophagy. Overall, my data provide insight into the molecular mechanisms contributing to the pathogenesis of preeclampsia.

Keywords: placenta
preeclampsia
Mtd/Bok
Mcl-1
autophagy
oxidative stress
Advisor: Caniggia, Isabella
Chemical Transmission between Dorsal Root Ganglion Somata via Intervening Satellite Glial Cell

The structure of afferent neurons is pseudounipolar. Studies suggest that they relay action potentials (APs) to both directions of the T-junctions to reach the cell body and the spinal cord. Moreover, the somata are electrically excitable and shown to be able to transmit the signals to associated satellite cells. Our study demonstrates that this transmission can go further and pass onto passive neighbouring somata, if they are in direct contact with same satellite cells. The neurons activate the satellite cells by releasing ATP. This triggers the satellite cells to exocytose acetylcholine to the neighbouring neurons. In addition, the ATP inhibits the nicotinic receptors of the neurons by activating P2Y receptors and initiating the G-protein-mediated pathway, thus reducing the signals that return to the neurons that initiated the signals. This “sandwich synapse” represents a unique pathway by the ectopic release between the somata and the satellite cells.

Keywords: satellite glial cell
dorsal root ganglia
neuron-glial interaction
patch clamp technique
Advisor: Stanley, Elise F.
Linker-based Lecithin Oral Drug Delivery Systems

In this study, pharmaceutical-grade and food-grade linker-based lecithin self-emulsifying delivery systems (SEDS) were developed with a combination of lipophilic and hydrophilic linkers. These additives at suggested concentrations are safe for pharmaceutical and food applications. The ratio of surfactant lecithin and linkers in these systems was optimized to develop surfactant in oil preconcentrates. The preconcentrates containing different surfactant concentrations and oil were diluted with fed state simulated intestinal fluid to produce pseudo-ternary phase diagrams and to identify the formulations that produced self-emulsifying or self-microemulsifying delivery systems. Optimal SEDS preconcentrates were evaluated using a dialyzer model to simulate intestinal uptake. An uptake of 39.6 mg/cm2 for the pharmaceutical-grade SEDS was obtained within 72 minutes, which promises substantial improvement in the bioavailability of hydrophobic actives. The optimal uptake of 12.2 mg/cm2 for food-grade SEDS suggests enhancement in the bioavailability of omega-3 fatty acids.

Keywords: Self-emulsifying delivery system
Microemulsion
Linkers
Uptake
Pseudo-ternary phase diagram
Omega-3 ethyl esters
β-sitosterol
Advisor: Acosta, Edgar
The Prospect for Health Care Rights in China

The 2009 reform of China’s health care system attempts to lower the burden of medical costs and provide universal access to health care. This thesis focuses on a particular access and equity gap within the health care system that faced by internal migrants, and explores the potential value of a legally enforceable and justiciable right to health care in the Chinese context to address such gaps. Despite recent advances in the health care reform, lack of a framework of health care rights could be a limiting factor to current health care initiatives which are falling short of their promises of universality in some way. In the long run, establishment of such framework could be a direction that deserves further research.

Keywords: human rights
health care
health insurance
migrant
Advisor: Flood, Colleen M.
Intestinal Cholecystokinin Controls Glucose Production through a Neuronal Network

Cholecystokinin (CCK) is a gut peptide involved in the regulation of energy homeostasis by duodenal lipids via a neuronal network. However, it is unknown whether CCK also regulates glucose homeostasis through a neuronal network. Using an in vivo rat model, we demonstrated that duodenal CCK-8 (biologically active form of CCK) can lower glucose production through the activation of a gut-brain-liver axis via CCK-A receptors, and this glucose-regulatory effect is physiologically relevant. Since duodenal lipids can also lower glucose production through a gut-brain-liver axis, we verified that this duodenal-lipid effect is mediated by CCK-A receptor activation. Lastly, in rats fed on a high-fat diet for three days, duodenal CCK failed to suppress glucose production, suggesting a state of CCK-resistance. In summary, these findings revealed that intestinal CCK can regulate glucose homeostasis through a neuronal network and suggest that intestinal CCK resistance may contribute to hyperglycemia in response to high-fat feeding.

Keywords: gut
CCK
Advisor: Lam, Tony K. T.
Identification of Germline Alterations in the Mad-homology 2 (MH2) Domain of SMAD3 and SMAD4 In Breast Cancer Susceptibility

A feature of neoplastic cells is that mutations in the key intermediates of TGF-β signaling contribute to the loss of sensitivity to its anti-tumor effects. The role of SMAD3 and SMAD4 germline mutations in breast cancer predisposition is currently unclear. To address this, mutation analysis of the Mad-Homology 2 domains in 408 breast cancer cases and 710 controls recruited by the Breast Cancer Family Registry (BCFR) was performed using Denaturing High-Pressure Liquid Chromatography. This study identified 23 distinct intronic variants, and three coding variants c.1214T>C, c.1478G>A, and c.1701A>G in SMAD4. No aberrant splicing was observed, but qPCR analysis and tissue expression data showed significantly elevated SMAD3 expression relative to controls (p<0.05). For SMAD4, c.1478G>A from a familial breast cancer case showed a 5-fold expression change. Taken together, inactivating alterations are not driving tumorigenesis. Rather, aberrant germline expression provides novel insight into SMAD3 and SMAD4’s roles in breast cancer predisposition.

Keywords: Breast cancer
germline mutations
SMAD3
SMAD4
Bioinformatics
Advisor: Ozcelik, Hilmi
The Coordination of Secured Transactions Law and Insolvency in Canada: A Successful Model of Bijuralism for the EU?

This paper deals with the interaction of insolvency and secured transactions law in a “bijural” jurisdiction, composed of sub-jurisdictions that come from different legal origins. It gives an introduction to bijuralism and then examines an example, namely the interaction of Canadian insolvency law and provincial secured transactions law. It stresses the different origins of Anglo-Canadian law and Québec law, in particular the difference in property law between the two and how it affects secured transactions law. It argues that given these fun- damental differences, the provinces have achieved a relatively harmonized secured transac- tions law. The paper goes on to compare the interaction in Canada with the interaction of European law and the law of EU member states. While the Canadian experience can serve as an example for the interaction in Europe, it also demonstrates shortcomings that need to be addressed in Canada as well as by a European insolvency legislator.

Keywords: Secured Transactions
Bijuralism
Advisor: Duggan, Anthony
The Hormonal Regulation of Non-breeding Territorial Aggression in North American Red Squirrels (Tamiasciurus hudsonicus)

Classically, testosterone (T) was considered the principal regulator of aggression. However, recent studies in birds have found aggression and T uncoupled during the non-breeding season. Circulating testosterone comes with costs such as immunosuppression and energy expenditure. Instead, the pro-hormone, dehydroepiandrosterone (DHEA), is circulated and activated within the brain via conversion into oestradiol (E2), avoiding the costs associated with T. At present the site of DHEA synthesis is unknown. My thesis investigated the existence of an analogous pathway in non-breeding red squirrels (Tamiasciurus hudsonicus) with two studies: (a) a field study investigating the effects of E2 on aggression and (b) a laboratory study that attempted to determine the site of DHEA synthesis. I conclude that E2 regulates non-breeding aggression in red squirrels and that the adrenals are not the site of DHEA synthesis. My results suggest the existence of a mammalian analogue to the regulatory pathway found in birds.

Keywords: Non-breeding aggression
Red squirrels
DHEA
Oestradiol
Adrenals
Gonads
ACTH
GnRH
Advisor: Boonstra, Rudy
"Green" Doesn't Always Make Good Impressions: Evaluations of Different Types of Environmentalists

In the present research, I examined individuals' evaluative responses toward traditional representations of environmentalists (e.g., tree-huggers and radical activists) as well as less typical but more mainstream environmentalists. Undergraduate students read about one of three types of environmentalists (i.e., radical activist, tree-hugger, or mainstream environmentalist). Participants then rated the extent to which they liked the individual they read about. Results revealed that participants evaluated the tree-hugger and radical activist less favourably than a typical student. In contrast, participants responded as favourably toward the mainstream environmentalist as they did toward a typical student. These findings indicate that individuals have distinct impressions of different types of environmentalists: Whereas mainstream environmentalists may receive favourable evaluations from individuals, stereotypical environmentalists may elicit negative reactions and even alienate members of the public.

Keywords: environmentalist
person perception
evaluation
subgroup
Advisor: Lockwood, Penelope
Chasteen, Alison L.
Generation, Yes? Digital Rights Management and Licensing, from the Advent of the Web to the iPad

The Article discusses digital-era courts’ distortion of (para)copyright principles, deeming it borne of jumbled underlying legislation and a misplaced predilection for adopting licensing terms—even at the expense of recognized use exceptions. Common law evolutionary principles, it is shown, have been abandoned just when they are most needed: the ethereal rightsholder-user balance is increasingly disturbed, and the incipient “generative consumer” is in thrall, not liberated. Finally, the Article puts forth a proposal for the reestablishment of the principle of substantially noninfringing use, showing it to be in the interests of innovation, democracy, and the greater public interest.

Keywords: DRM
Licensing
Advisor: Drassinower, Abraham
PAKs 1 & 3 Control Postnatal Brain Development and Cognitive Behaviour through Regulation of Axonal and Dendritic Arborizations

The molecular mechanisms that coordinate postnatal brain enlargement, synaptic properties and cognition remain an enigma. This study demonstrates that neuronal complexity controlled by p21-activated kinases (PAKs) is a key determinant for postnatal brain enlargement and synaptic properties. Double knockout (DK) mice lacking both PAK1 and PAK3 were severely impaired in postnatal brain growth, resulting in a dramatic reduction in brain volume at maturity. Remarkably, the reduced brain was accompanied by minimal changes in total cell count, due to a significant increase in cell density. However, the DK neurons have smaller soma, markedly simplified dendritic arbors/axons and reduced synapse density. Surprisingly, the DK mice were elevated in basal synaptic responses due to enhanced individual synaptic potency, but severely impaired in bi-directional synaptic plasticity. The PAK1/3 action is likely mediated by cofilin-dependent actin regulation because the activity of cofilin and the properties of actin filaments were specifically altered in the DK mice.

Keywords: PAK
neuronal morphogenesis
synaptic plasticity
microcephaly
synapse
dendritic arborization
Advisor: Jia, Zhengping
Development of an Activated Carbon from Anaerobic Digestion By-product to Remove Hydrogen Sulfide from Biogas

The production of biogas through the anaerobic digestion of cattle manure and its subsequent use in the generation of electricity on large Ontario farms is currently economically attractive. While larger farms have advantages of scale, there are substantially more small farms for which individually designed and engineered biogas systems are prohibitively expensive. Although biogas has numerous benefits, it contains hydrogen sulfide, an odourous, poisonous and corrosive gas, which emits sulfur oxides upon combustion. Larger systems can afford to use specialized biogas engines which tolerate some levels of hydrogen sulfide. For smaller scale systems to be financially attractive the hydrogen sulfide needs to be removed inexpensively, allowing for more flexibility in engine choice for electricity generation. In this work, the solid by-products from the anaerobic digestion process were used to create activated carbon, which has a high capacity for hydrogen sulfide. Not only does the carbon adsorb hydrogen sulfide, it allows for the surface oxidation of hydrogen sulfide to elemental sulfur and sulfate. Since the sulfur is in a beneficial form for fertilizer use, and there are no chemicals added to create the carbon, the spent sulfur-containing carbon can be land applied, eliminating any spent carbon disposal costs.

Keywords: biogas
activated carbon
hydrogen sulfide
anaerobic digestate
Advisor: Kirk, Donald W.
Development of Flexible and Optically Transparent Composite Film with Wheat Straw Nanofibres

Cellulose is a potential source of nano-material not only because it possesses excellent mechanical and optical properties, but also because it is environmentally benign. In this study, nanofibres derived from wheat straw, an agriculture residue, was utilized in producing flexible and optically transparent nanocompostie films. The composites were produced using a bi-phase impregnation technique that coats the dried nanofibre films with clear polyurethane acrylate resins using UV radiation induced curing. The nanocomposite films thus produced possess excellent tensile properties (161MPa in strength and 9GPa in Young’s Modulus), superior thermal stability (above 300°C), low coefficient of thermal expansion (8-9ppm/K), good light transparency (80%), excellent flexibility and abrasion resistance. These nanocomposite films are aimed to replace the conventional glass substrates made in batches to a polymer based substrates that can be efficiently produced in a roll-to-roll process for the base of the future flexible flat panel displays.

Keywords: Cellulose Nanofibre
Wheat Straw
Composite Film
Acrylate
Flexible
Transparent
Display Substrate
Advisor: Sain, Mohini
Uncovering New Roles for Hsp90 in Candida albicans Morphogenesis

The trimorphic fungus Candida albicans is the leading cause of systemic candidiasis, a disease with poor prognosis affecting immunocompromised patients. The capacity to switch between growth morphologies is tightly coupled to its ability to cause life-threatening infection. Recently, the molecular chaperone Heat Shock Protein 90 (Hsp90) has been implicated as a major regulator of C. albicans morphogenesis via the Ras1-PKA pathway. In model organisms from plant, animal and fungal kingdoms, Hsp90 stabilizes regulators of cell signaling and participates in many important cellular processes. Hsp90’s roles in C. albicans are beginning to be dissected. This thesis represents a comprehensive overview of the morphological response of C. albicans to compromised Hsp90 function, illuminating previously unidentified roles for this chaperone in cell cycle progression, cytokinesis and vacuole maintenance. This work sheds light on the importance of Hsp90 in fungal development and the therapeutic potential of Hsp90 inhibitors in the treatment of fungal infections.

Keywords: Candida albicans
Molecular chaperone
Cell biology
Cell cycle
Cytokinesis
Vacuole
Morphogenesis
Hsp90
Mycology
Microbiology
Mitosis
Advisor: Cowen, Leah
Resonant Boost Converter for Distributed Maximum Power Point Tracking in Grid-connected Photovoltaic Systems

This thesis introduces a new photovoltaic (PV) system architecture employing low voltage parallel-connected PV panels interfaced to a high voltage regulated DC bus of a three-phase grid-tied inverter. The concept provides several improvements over existing technologies in terms of cost, safety, reliability, and modularity. A novel resonant mode DC-DC boost converter topology is proposed to enable the PV modules to deliver power to the fixed DC bus. The topology offers high step-up capabilities and a nearly constant efficiency over a wide operating range. A reduced sensor maximum power point tracking (MPPT) controller is developed for the converter to maximize energy harvesting of the PV panels. The reduced sensor algorithm can be generally applied to the class of converters employing pulse frequency modulation control. A ZigBee wireless communication system is implemented to provide advanced control, monitoring and protection features. A testbench for a low cost 500 W smart microconverter is designed and implemented, demonstrating the viability of the system architecture.

Keywords: DC-DC converter, step-up, boost, converter, MPPT, grid-connected, photovoltaic, power electronics, efficient, high efficiency, high step-up ratio, novel, distributed MPPT, peak power tracking, frequency, control, pulse frequency modulation
Advisor: Lehn, Peter W.
Urinary Composition and Stone Formation

Background: Kidney stone disease is a common and often debilitating disorder, yet its pathophysiology is poorly understood. This dissertation studies predisposition to kidney stone formation from diurnal variation in physiochemical and physiologic properties of urine and in response to increased fluid intake. Methods: Urine volume, flow rate and constituents were measured in multiple timed specimens from healthy volunteers in a day. Further, subjects were asked to provide specimen over a period of increased fluid intake. Results: A 24-hour specimen missed significant periods of supersaturation in individual urine samples throughout the day. Despite a significant reduction in nocturnal urine flow rate, calcium concentration as well as urine pH and divalent phosphate remained unchanged. Finally, increased water intake did not dilute urine evenly. Conclusion: Mixing multiple urine samples obscures information about periods of increased calcium phosphate precipitation risk over 24 hours. Further, increased fluid intake does not uniformly provide risk protection.

Keywords: Nephrology
Medical Science
Advisor: Logan, Alexander
Saccade Related Gamma Potentials Recorded in Human Subthalamic Nucleus, Globus Pallidus Interna and Ventrointermediate Nucleus of the Thalamus

Gamma oscillations of local field potentials (LFP) in the basal ganglia and thalamus had not been studied during saccades. Eleven patients were studied during deep brain stimulation (DBS); 6 were in the subthalamic nucleus (STN); 3 in the globus pallidus interna (GPi); and 2 in the thalamic ventralis intermedius nucleus (Vim). Patients performed horizontal saccades to visual targets while LFPs from DBS electrodes, scalp electroencephalogram (EEG), and electrooculogram (EOG) were recorded. Wavelet spectrograms were generated and saccade onset and event-related gamma synchronizations (ERS) were compared to baseline without eye motion. ERS were recorded at and after saccade onset in the STN, GPi and Vim, EEGs and EOGs; but were absent during target light illumination without saccades. ERS were symmetric in all DBS contacts and appeared identical in DBS LFPs, frontal EEGs and EOGs. These findings indicate their origin from extraocular muscle spike potentials rather than brain neural activity.

Keywords: Gamma oscillations
Saccadic Spike potentials
Local field potential oscillations
Deep brain stimulation
Gamma artifact
Subthalamic nucleus
Globus pallidus interna
Ventrointermediate nucleus
Advisor: Sharpe, James
Hutchison, William D.
Visualization of the Crystallization in Foam Extrusion Process

In this study, crystal formation of polypropylene (PP) and poly lactic acid (PLA) in the presence of CO2 in foam extrusion process was investigated using a visualization chamber and a CCD camera. The role of pre-existing crystals on the foaming behavior of PP and PLA were studied by characterizing the foam morphology. Visualization results showed that crystals formed within the die before foaming and these crystals affect the cell nucleation behavior and expansion ratio of PP and PLA significantly. Due to the fast crystallization kinetics of PP, crystallinity should be optimum to achieve uniform cell structure with high cell density and high expansion ratio. In PLA, enhancement of crystallinity is crucial for getting foam with a high expansion ratio. It was also visualized that CO2 significantly suppresses the crystallization temperature in PP through the plasticization effect as well as its influence on flow induced crystallinity.

Keywords: Visualization
Crystallization
Foam Extrusion
Advisor: Park, Chul B.