VictorJuiz/thesis huggingface dataset:
Functional Moderate to Severe Tricuspid Regurgitation in Adults undergoing Transcatheter Atrial Septal Defect Closure

Background: A large proportion of patients continues to have moderate to severe tricuspid regurgitation (TR) after transcatheter atrial septal defect (ASD) closure. Objective: To determine the clinical significance of functional TR in ASD patients and identify the baseline predictors of persistent TR after ASD closure. Methods: Clinical data were collected from hard-copy and electronic records at the University Health Network (UHN), Toronto, Canada. The clinical registry was linked to Ontario population-based health administrative databases. Results: Age ≥65 years, severe TR, and right ventricular systolic pressure (RVSP) were independent baseline predictors of persistent TR. ICES analyses showed patients with baseline moderate to severe TR (n=750) were not associated with higher cardiovascular mortality compared to patients with baseline mild/no TR (n=199) after adjust for cardiovascular co-morbidities. Conclusions: Perhaps offering early ASD closure or concomitant tricuspid valve intervention may be of benefit to patients at risk for persistent TR.

Keywords: Atrial septal defect
Congenital heart disease
functional tricuspid regurgitation
Interventional cardiology
long-term outcomes
survival
Advisor: Horlick, Eric
Corneal Neurotization Maintains Corneal Epithelial Integrity and Restores Nerve-derived Peptides in a Rat Model of Neurotrophic Keratopathy

PURPOSE: Investigate effect of corneal neurotization on epithelial integrity and restoration of nerve-derived peptides in denervated rat corneas. METHODS: Three rat corneal conditions were assessed (n=45): denervation, denervation + neurotization, normal innervation. Corneal epithelial and stromal thicknesses were evaluated using Hematoxylin and Eosin staining. Corneal ulceration and perforation were assessed under a Wood’s lamp and normal light, respectively. Immunohistochemistry and western blot were used to evaluate Substance P (SP) and calcitonin gene-related peptide (CGRP) presence. RESULTS: Where significance is p

Keywords: Corneal innervation
Corneal neurotization
Denervation
Nerve transfer
Neurotrophic keratopathy
Rat disease model
Advisor: Borschel, Gregory GH
Gordon, Tessa
Electromagnet Design for a Time Varying Magnetic Flux Leakage System

The aim is to design and build an optimized electromagnet for a time varying magnetic flux leakage (MFL) system that can operate within a frequency range of 0 – 10 Hz. The system will be used for the inspection of fuel storage tank floors. The advantage over DC systems is that the response of each frequency component would help in estimating the remaining plate thickness at a defect location; this is usually the main concern for fuel tanks. The electromagnet is designed with finite element modeling using COMSOL Multiphysics. Experimental results are compared with simulations and are used to validate the design. A prototype MFL system that utilizes the electromagnet is tested by inspecting steel plate samples with machined defects of different depths. Simulations are then used to demonstrate the ability of AC MFL to differentiate between defects that would be difficult to characterize with DC MFL alone.

Keywords: Electromagnet Design
Finite Element Modeling
Magnetic Flux Leakage
Nondestructive Testing
Advisor: Sinclair, Anthony
Filleter, Tobin
Examining an Event-related Brain Potential Index of Semantic Priming in Cannabis-using Individuals at Clinical High-risk For Psychosis

Individuals at clinical high-risk (CHR) for schizophrenia experience subthreshold symptoms of this disorder, and cannabis use further increases their risk of conversion to psychosis. To seek neurophysiological evidence that cannabis use is associated with semantic processing deficits in the CHR state, we used the N400 event-related potential (ERP) to measure semantic priming. We recorded ERPs in 15 cannabis-using and 12 non-cannabis-using help-seeking CHR individuals, and 10 cannabis-using and 15 non-cannabis-using healthy controls while they viewed related and unrelated prime-target word pairs, at a short and a long stimulus-onset asynchrony (SOA). We observed no significant differences in N400 semantic priming between the four groups, but observed a trend towards deficits at the long SOA in all CHR participants compared to all controls (p = 0.07). The results suggest that CHR individuals experience semantic priming deficits similar to those of schizophrenia patients but that cannabis use does not further impair this process.

Keywords: Addiction
Cannabis
Clinical high-risk
Event-related brain potential
Neurophysiology
Psychosis
Advisor: Mizrahi, Romina
Kiang, Michael
The Voices of Teachers on Mandated Changes to Math Curriculum and Policy

This study explores the issue of teacher underrepresentation in curriculum and policy development. The specific focus is on elementary public-school teachers in Ontario and their experiences with mandated changes to math curriculum and policy. Eight teachers were interviewed on this topic and a document analysis was conducted of curriculum, policies, and guides that are related to math education. The findings from the interviews and documents were triangulated through a conceptual framework that integrates sensemaking and contingency theories, to explore the relationship between individual responses to change and the constituents of an organization. Results from the analysis indicate that teachers are currently underrepresented in math curriculum and policy change processes even though they directly impact those changes. The findings carry significant implications for teacher roles and curriculum and policy development outcomes, emphasizing the need for congruent alignment between teachers’ voices and how the education system is structured.

Keywords: Education change
Math
Math education
Math reform
Ontario
Teachers
Advisor: Bascia, Nina
Development of a Geolocation and Tip-and-cue Observation System for the DEFIANT Platform

Surveillance capabilities in remote regions are currently limited by the low availability of permanent ground-based infrastructure. The University of Toronto Institute for Aerospace Studies Space Flight Laboratory’s next-generation DEFIANT-class spacecraft offers a solution to this problem through spaceborne monitoring. It features a wide suite of payloads to enable geolocation and autonomously cued observation of targets of interest. This work will detail the author’s efforts to develop this spaceborne surveillance system, with particular focus on the design of the attitude control system, the development of an algorithm for geolocation of radio-frequency-signal-emitting targets, and the formulation of an attitude path-planning algorithm to enable target observation and rapid spacecraft reorientation under a variety of dynamic and kinematic constraints. The developed concepts are validated through simulation and testing with reference to a hypothetical sample mission involving a controlled formation of DEFIANT spacecraft.

Keywords: Attitude Control
Control Systems
GNC
Guidance
Satellite
Space
Advisor: Zee, Robert E
Optimal Generation Redispatch and Visualization of Network Flows Considering Uncertainty

With an increasing amount of renewable generation present on the power grid, grid operators are faced with the challenge of incorporating intermittent energy resources that add uncertainty to the system. In this work, uncertainty in the net load is modeled as a set of forecast errors with known probability distributions. This probabilistic model is used within a robust optimization (RO) framework to formulate an optimal policy for generation redispatch that balances the system in the presence of forecast errors. The optimal generation redispatch policy is compared with conventional approaches to assess its suitability in the presence of large forecast errors. As a secondary contribution, network visualizations are obtained that map the uncertainty present in net load forecasts to transmission line flows; these visualisations can be of use in increasing the situational awareness of grid operators. A case study is performed on a 37-bus test system and conclusions are drawn.

Keywords: Generation
Redispatch
Uncertainty
Visualization
Advisor: Tate, Joseph E
Likelihood to Recommend (L2R) Prediction using Quality of Experience (QoE) Measurements: A Longitudinal Study

Models that predict satisfaction with a service over time need to consider the impact of emotions and remembered quality of experience in predicting overall attitudes towards a service. However, prior research on the subjective of quality of experience has typically focused on experiments conducted in a single session or over a short period of time. Thus, there is a gap between our understanding of instantaneous quality of experience and long-term judgments, such as overall satisfaction, and likelihood to recommend and likelihood to churn. The goal of the study reported here was to carry out a longitudinal study that would provide initial insights into how experiences of service quality over time are accumulated into memories that then drive longer term attitudes about the service. Our longitudinal study was carried out over a period of roughly 4 weeks with around 3 sessions per week.

Keywords: Human Factors Engineering
Psychology of service
Service
Technical Quality
Telecommunication
Advisor: Chignell, Mark
Improving Timely Access to Emergency Diagnostic Imaging via Data Analysis and Discrete Event Simulation

As one of its initiatives to improve timely access to diagnostic imaging and expedite care in the emergency department (ED), Sunnybrook Health Sciences Centre implemented a 24/7 in-house attending radiologist coverage model to service its ED in 2017. This thesis initially describes how this new coverage model impacted imaging report turnaround times (TAT), it then discusses how a discrete event simulation was used to evaluate the impact of process changes on emergency computed tomography (CT) overall TAT. The 24/7 coverage evaluation indicated that the new model led to significant reductions in report TAT for almost all imaging modalities; and the scenarios tested with simulation model showed that simplifying exam protocols, changing staff schedules, and improving exam booking processes can considerably shorten CT overall TAT and likely contribute to enhanced patient care.

Keywords: discrete event simulation
healthcare
medical imaging
Advisor: Carter, Michael W
Constructing the Promise of Play: Exploring the Concept of Play in Stuart Brown and Brian Sutton-Smith’s Collaborative Efforts

What is the promise of play? In this thesis, I explore how two preeminent play advocates, Stuart Brown and Brian Sutton-Smith, attempted to construct a comprehensive answer to this question during their collaborative efforts between 1991 and 2001. Engaging their archival materials located at the Strong Museum in Rochester, New York, I examine how Brown and Sutton-Smith sought to gain support for their project The Promise of Play by conceptualizing play as a singular phenomenon worthy of intellectual and public attention. Working from a Bourdieusian framework, I posit that Brown and Sutton-Smith’s collaborative efforts create space to explore how meaning about play is produced through exchanges, negotiations, and differences in opinion, that is, through relations. Instead of accepting play as an inherently promising concept or subject of study, I examine how this notion appears within the context of Brown and Sutton-Smith’s collaboration, and interrogate its implications for Play Studies today.

Keywords: Archival Research
Bourdieu
Brian Sutton-Smith
Play
Play Theory
Stuart Brown
Advisor: Farmer, Diane
A Comparative Study of the Electro-dewatering of Pulp and Paper Mill Biosludge

The activated sludge process, often used in pulp and paper mills, generates biosludge that requires dewatering. Wastewater treatment practices and upstream processes impact biosludge characteristics, including dewaterability. Electro-dewatering, compared to other dewatering methods, has a high dewatering potential while requiring low amounts of energy. The main objective of this study was to determine the variation in the characteristics of mill biosludge and its impact on electro-dewatering. Biosludge was sampled from four different wastewater treatment plants, including a municipal one as cross-reference, and characterized for various properties. Using a bench-scale electro-dewatering device, thickened biosludge was subjected to constant-voltage electro-dewatering at 20 V. Electro-dewatering successfully removed 68-74% of the water while consuming between 0.15 and 0.56 kWh/kg additional water removed. Overall, varying biosludge characteristics did not impact the total amount of water removed, but certain characteristics, particularly the electrical conductivity, dictated the routes of water removal (evaporation, filtration) and energy consumption.

Keywords: Biosludge
Dewatering
Electro-dewatering
Pulp and paper mills
Separation
Wastewater Treatment
Advisor: Allen, David G
Tran, Honghi N
Understanding and Mitigating the Effects of Operating Room Distractions

Operating rooms (ORs) are complex dynamic environments with frequent distractions. Literature has limited evidence on OR distractions leading to adverse surgical outcomes; in fact, studies increasingly agree that distractions under certain circumstances can be beneficial. A notable limitation of existing studies is the drawbacks of data collection methods. This study is the first to use a naturalistic dataset, the OR Black Box, to investigate the relation of OR distractions and intraoperative technical events. Increased machine alarm rates, decreased technical skill levels, and increased body mass index levels were found to be associated with increased likelihood of observing more than one severe technical event during high criticality/medium-high difficulty procedural steps of Roux-en-Y gastric bypass operations. Mitigation strategies to reduce the negative effects of OR distractions were identified through a literature review and discussions with OR members. A taxonomy was created through systems perspective to support the selection of appropriate mitigation strategies.

Advisor: Donmez, Birsen
Hardening of Light-polymerized Resin Cements through Lithium Disilicate Glass-ceramic Veneers

Aim: To evaluate effect of ceramic veneer type and thickness on light attenuation and microhardness of light-polymerized resin cements. Methodology: Three types of ceramic blocks were used (IPS E.max-CAD, Celtra-Duo and VITABLOCS Esthetic-Line). Specimens measuring .5, 1 and 1.5 mm were cut. Deep-cure and Blue-phase light-polymerizations units were used. Light irradiance through specimens was measured with MARC-Patient Simulator. Rely-X Veneer and Variolink-Esthetic resin cements were polymerized through ceramic specimens for 10 and 20 seconds. Microhardness of cement specimens was measured using tester with Knoop indenter. Result: Ceramic type and thickness had statistically-significant effects on light attenuation. Mean microhardness of Rely-X Veneer cement was significantly higher than that of Variolink Esthetic. Moreover, direct correlation was found between polymerization time and mean microhardness for both cements. Conclusions: Increased veneer thickness negatively affected light irradiance in a significant manner. Light attenuation resulted in significant decrease in mean surface microhardness for both cements.

Keywords: Hardness
Lithium Disilicate Glass Ceramic
Resin Cement
Veneers
Advisor: El-Mowafy, Omer
The Role of Human Leukocyte Antigen-G and its Polymorphisms in Post-transplant Malignancy and Acute Rejection Following Heart Transplantation

Human leukocyte antigen-G (HLA-G) has shown to increase cancer risk but reduce rejection post-transplant by dampening the immune response. Cancerous cells may utilize HLA-G as a mechanism to evade the immune response. HLA-G expression is mediated by genetic polymorphisms, however their association with post-transplant outcomes remains elusive. The objective was to evaluate HLA-G donor-recipient polymorphism matching and development of cancer/rejection following heart transplantation. Recipients (n=251) and donors (n=196) were genotyped to identify HLA-G polymorphisms in the coding, 5’regulatory and 3’untranslated regions. Association between outcomes and polymorphism matching was assessed via cox regression. Overall, 17% of recipients were diagnosed with cancer post-transplant. Donor- recipient 14BP polymorphism matching reduced the proportion of cancer and was independently protective against cancer development (HR[95%CI]: 0.26 [0.10-0.75], p=0.012). HLA-G may have a role in targeted therapeutic and diagnostic strategies against cancer. Identifying relevant HLA-G polymorphisms may warrant alterations in immunotherapy in order to reduce cancer risk post-transplant.

Keywords: Acute Rejection
Cancer
Heart Transplantation
HLA-G
Immune Checkpoint
Polymorphisms
Advisor: Rao, Vivek
Sex Differences in Health Care Utilization Preceding an Initial Heart Failure Hospitalization

Timely diagnosis of HF is recognized as a challenge and there is a paucity of knowledge about health care utilization before HF is diagnosed. In a retrospective population-based study, health care contacts leading up to an incident HF hospitalization were examined and compared to two control groups: incident chronic pulmonary obstructive disease hospitalization and non-hospitalized matched population. Multivariable negative binomial regression models for repeated events were used to evaluate predictors of higher rate of health care contacts preceding incident hospitalization. A total of 55,743 adults were hospitalized with de novo HF. HF patients had a higher rate of health care contacts per 28-day period prior to hospitalization compared to controls. Sex was not a significant predictor of rate of health care contacts, but women had significantly less investigations performed. There are missed opportunities for earlier diagnosis and prevention of HF hospitalization in patients with de novo HF.

Keywords: health care
heart failure
sex
trajectory
Advisor: Lee, Douglas S.
Impact of Grid-fed Electric Vehicle DC Fast Charging Station on the Utility Grid

Fast recharging of EVs from grid-connected chargers requires a large amount of power which can adversely affect the grid. This thesis investigates impacts of a grid-connected DC fast charging station (DC-FCS) on the utility grid and proposes an energy storage system (ESS) to mitigate the impacts. A study system consisting of a distribution feeder, a DC-FCS and an ESS is selected. The study system is used for time-domain simulation studies to evaluate steady-state and transient operations of the DC-FCS with and without the ESS in the PSCAD/EMTDC platform. The steady-state performances are studied under different Short-Circuit Ratio (SCR) values, and degrees of voltage unbalance. The transient performances are studied by introducing load changes and fault scenarios. The offline simulation results are verified by using Control-Hardware-In-the-Loop (CHIL) in RTDS-based real-time simulation platform. The study results demonstrate that the ESS can mitigate adverse effects caused by peak charging demand of the DC-FCS.

Keywords: DC Fast Charging Station
DC Fast Charging Station on the Utility Grid
Electric Vehicle DC Fast Charging
Grid-Fed Electric Vehicle
Impact of Grid-Fed Electric Vehicle
Advisor: Iravani, Reza
System Level Communication Challenges of Large FPGAs

As FPGA capacity and the complexity of the designs implemented on them have grown, so too have system-level communication challenges. At the design level the typical latency of long distance interconnect grows making them the limiting factor in reaching timing for a design. We explore the use of latency-insensitive design (LID) as a solution. Our best approach gained 2x area efficiency and 18\% less critical path delay over traditional LID, and come at a minimal speed overhead of 3\% compared to a latency-sensitive design. At the architecture level the number of clocks has grown. It is challenging to supply global clocks to all modules efficiently. Therefore, the clock architecture must be flexible to allow for smaller and more power efficient networks to be built. We present a flexible clock modeling format, built into open source CAD tool VPR, to allow clock impacts and architecture options to be explored.

Keywords: Clock Modeling
Computer-Aided Design
FPGA
Latency Insensitive
Advisor: Betz, Vaughn
Liver Hemodynamics in Fontan Patients

A novel analysis of liver hemodynamics, described by flow rates and pressures, and their associations with liver disease was carried out in Fontan patients. The flow analysis revealed that morphologic evidence of liver disease is associated with statistically significant reduction in flow rates in the superior mesenteric artery, portal vein, hepatic vein, and Fontan pathway. Simulations of liver hemodynamics using a patient-specific detailed lumped parameter model for Fontan patients showed excellent agreement to in vivo patient measurements. This model illustrated the fallacy of using the hepatic venous pressure gradient in estimating the liver pressure gradient associated with the degree of liver fibrosis. Additionally, the model provided estimates of liver pressures and compliances that were generally higher and lower, respectively, in Fontan patients with liver disease. Implementation of the mentioned hemodynamic parameters in clinical settings could enable better screening of Fontan liver disease and help in providing more personalized patient care.

Keywords: Computational Modelling
Fontan
Liver disease
MRI
Velocity mapping
Advisor: Amon, Cristina H.
A CMOS, Fully Integrated, Inductively Coupled, Wireless Data Transfer System

This thesis presents the design and implementation of a wireless data transfer system from a mm-sized fully integrated CMOS chip with an on-chip power harvesting coil. Data transfer fundamentals are investigated in the context of an inductively coupled wireless power link. By modulating the resonance frequency of the on-chip coil, the prototype is capable of transmitting data to an off-chip receiver. Demodulation is accomplished via homodyne receiver architecture with a circulator in the signal path. A PCB circuit-based circulator is designed and compared in functionality to a ferrite-based circulator in order to decrease the size and cost of the receiver. Data is successfully demodulated by the external receiver using a PCB-realized primary coil at distances of 8mm with BER

Keywords: Fully Integrated
Inductively Coupled
Wireless Data Transfer
Wireless Power Transfer
Advisor: Gulak, Glenn
The Effect of Scyllo-inositol on the Neurodegeneration Induced by Alpha-synuclein Fibril Transmission in Mice

Recent literature suggests that inoculation of non-transgenic and transgenic mice with synthetic alpha-synuclein preformed fibrils can seed the formation of Parkinson-like pathology, implicating aggregation of alpha-synuclein in the pathogenesis of Parkinson's disease. The therapeutic scyllo-inositol, an established amyloid inhibitor, was tested to determine potential inhibitory effects on alpha-synuclein aggregation. In vitro experiments were used to establish inhibitor efficacy and demonstrated that scyllo-inositol prevented the aggregation of alpha-synuclein at multiple concentrations. To generate alpha-synuclein seeds for further in vitro and in vivo studies, alpha-synuclein fibres were sonicated as previously described. The seeds demonstrated potent acceleration of monomeric alpha-synuclein aggregation in vitro and thus were injected into the striata of two mouse models to seed pathology. Injected seeds did not demonstrate additional pathology in either model, in vivo. Altogether, scyllo-inositol interacts with alpha-synuclein demonstrating anti-aggregation effects in vitro and may function as a potential therapeutic in vivo will require further investigation.

Keywords: alpha-synuclein
Alzheimer's disease
amyloid-beta
Parkinson's disease
scyllo-inositol
Seeding
Advisor: McLaurin, JoAnne