VictorJuiz/thesis huggingface dataset:
Assessment of the Impact of Antegrade Enema Insertion on Health Care Utilization in Pediatric Patients with Constipation: A Population-based Cohort Study

Constipation is a common condition in the pediatric population which leads to high patient morbidity and a large burden on health care systems. Children with medically refractory constipation may undergo placement of an antegrade enema. We performed a population-based study to assess the impact of antegrade enema insertion on health care utilization. We identified that in pediatric patients following antegrade enema insertion, health care utilization remains stable for most forms of care, although emergency department health care use increases, in part secondary to device-related visits. Some forms of constipation-related care may decrease following antegrade enema insertion specifically in patients with functional constipation, though further work is needed to explore these findings. This thesis expands our understanding of the clinical success and financial impact of antegrade enemas and will aid clinical decision making for children with medically refractory constipation and allocation of health resources to manage these patients.

Keywords: Antegrade enema
Constipation
Gastroenterology
Health care utilization
Motility
Pediatric
Advisor: Walsh, Catharine M
Retention of Third Molars Pose a Risk for Delay in Cancer Therapy; A New Perspective on the Relative Need for Extraction of Impacted Third Molars in Young Adults

Purpose: Cancer treatment leads to deleterious effects on oral health. This study investigates the impact of retained third molars in the oncologic patient population. Methods: A 6-year retrospective review of new patients presenting to the Princess Margaret Hospital Dental Oncology clinic was conducted. Cancer patients who were awaiting cancer therapy and who had retained third molars were identified, and data regarding third molar position and problems was collected. Results: 2,431 pre-treatment new cancer patients were identified who had at least one retained third molar. 60% of patients had a third molar-related treatment dilemma. 26% of patients experienced a potential third molar related delay in cancer treatment, and 34% of patients underwent observation-only prior to initiating cancer treatment had an increase in the risk for delayed cancer treatment. Conclusion: There is a high prevalence of potentially problematic retained third molars in oncology patients, which may be a consideration for high-risk patients.

Keywords: cancer
head and neck
third molars
wisdom teeth
Advisor: Lam, David K
Love Under Lockdown? How a Change in Time Spent Together Impacts Romantic Relationships

With the onset of Covid-19, many governments globally implemented strict social distancing and stay-at-home orders to lessen virus spread. Due to pandemic-related lockdowns, individuals may be spending more (or less) time with relationship partners potentially affecting their relationships outcomes. In a pre-registered study, I examined whether attachment style would interact with a change in the amount of time individuals spend with their partner on their commitment, satisfaction, and relationship importance. A multiple regression using 665 participants from Prolific revealed that attachment avoidance significantly interacted with a change in time spent with a partner on outcome variables. Contrary to predictions, more avoidantly attached individuals reported more positive relationship outcomes when they were spending an increased, relative to a decreased, amount of time with their partner. Exploratory analyses revealed stress and individuals’ partner fulfilling their needs mediated the impact of a change in time spent together by couples on their relationship outcomes.

Keywords: Attachment style
Commitment
Covid-19 pandemic
Relationship Importance
Romantic relationship
Satisfaction
Advisor: Lockwood, Penelope
Novel Tissue Preservation and Transport Solution

The current laboratory tissue fixative is formalin, a type 1 carcinogen and biohazard alluding to environmental, disposal and legal costs. Beyond these consequences, formalin creates crosslinks with the specimen leading to masked epitopes. This thesis is the development of a novel preservation media composed of Low Potassium Dextran Glucose (LPDG), 10% honey and 1% coconut oil, named, Amber. This work investigated histological preservation of Amber in comparison with formalin, epitope integrity with immunohistochemistry (IHC) and immunofluorescent (IF) staining, and nucleic acid extraction. Results show histological superiority of Amber in animal and human tissue. IHC showed non-inferior staining of Amber by comparison to formalin. IF VE-cadherin and α-SMA expression showed increased epitope preservation in Amber groups, particularly in lung. Total RNA and RNA quality was comparable to Amber and fresh tissue. This work demonstrates Amber, a media that maintains high quality morphology without compromising the ability to perform immunostaining and nucleic acid extraction.

Advisor: Keshavjee, Shaf
Murphy, Kieran
TRAP+ Cells: Potential Mediators of Peri-implant Bone Healing

Multinucleated giant cells (MNGCs) at the dental implant interface have been implicated in a foreign body reaction, but have also been frequently observed at implant surfaces even years after implantation. In addition, there is growing evidence that implicates TRAP+ MNGCs as mediators of wound healing. However, samples containing metallic dental implants must be resin embedded, which has prevented the histochemical characterization of such peri-implant MNGCs to date. To address the hypothesis that peri-implant MNGCs are TRAP+, mini-implants were placed in the mandible of rabbits and processed for Osteo-Bed or Technovit 9100 resin embedding. Osteo-Bed embedded samples illustrated a previously unidentified form of peri-implant bone formation, termed ‘spontaneous’ osteogenesis. Results showed that TRAP staining was only successful with Technovit 9100. Extracellular staining for TRAP was also evident suggesting a putative role in cell signaling. In conclusion, this work has demonstrated that MNGCs within the endosseous compartment of dental implants are TRAP+.

Advisor: Davies, John E
Approximate and Randomized ADMM-LP Decoding using Geometric Information of the Parity Polytope

We present two strategies to reduce the complexity of the alternating direction method of multipliers with linear programming (ADMM-LP) decoder for LDPC codes. The complexity bottleneck of ADMM-LP decoding is projection onto the parity polytope. We propose the sparse affine projection algorithm (SAPA), which projects onto the affine hull of the χ closest local codewords for each check of degree d, where χ can be significantly smaller than d. Unlike exact projection, SAPA does not require a water-filling process, thus can be implemented with lower per-iteration complexity. Furthermore, we present a randomized layered scheduling framework for ADMM-LP decoding. In the randomized schedule, instead of updating all checks in a single iteration, more problematic checks are updated more often by using priors based the location of replica vectors inside or on the parity polytope. We demonstrate the decoder converges significantly faster with this randomized scheduling, thus it is well suited for limited-iteration applications.

Keywords: Affine Projection Algorithm
Alternating Direction Method of Multipliers (ADMM)
Layered Decoding
Low-Density Parity Check (LDPC) Codes
Parity Polytope Projection
Randomized Decoding
Advisor: Draper, Stark C.
Mechanical Design and Development of High-Performance Microsatellite Platforms for Remote Sensing and Technology Demonstration

Small spacecraft are powerful platforms for hosting specialized space-based payloads. They can service roles such as communications, Earth-observation and technology demonstration. This thesis discusses the engineering development of the NorSat-TD and GHGSat C3, C4 and C5 microsatellite missions at the Space Flight Laboratory (SFL). The NorSat-TD mission will advance the state-of-the-art in small-satellite technology demonstration capability. Based on SFL's DEFIANT microsatellite platform, the spacecraft will perform ship tracking as a primary mission and spacecraft technology demonstration as a secondary mission. The structural dynamics of the spacecraft and the nuanced assembly process is explored. The GHGSat mission is a cluster of Earth-observation satellites built for GHGSat Inc. Based on the NEMO platform, they will detect methane emissions from anthropogenic sources. The mechanical design of subsystems, assembly, and testing are discussed. The development culminated in the successful launch of a mission that pushes the envelope of Earth-observing microsatellite capabilities.

Keywords: dynamics
isolator
microsatellite
spacecraft
thermal
vibration
Advisor: Zee, Robert E
The Application of Dialysis and Metabolomics to Preserve Heart Function During Ex Situ Heart Perfusion

Heart failure affects 7.5 million people globally and is the primary cause of death for over 300,000 people annually in North America. The gold standard treatment for eligible end-stage heart failure patients is heart transplantation. However, even with extended donation criteria, there is a mismatch between the number of donors and recipients. Beyond the use of donation after brain death (DBD) organs, hearts obtained from donation after circulatory death (DCD) donors have been proposed as an alternative to expand the donor pool. Ex situ heart perfusion (ESHP) has been developed as a platform to revive hearts outside the body and can be used to evaluate heart function after DCD, prior to transplantation. Unfortunately, heart function declines during prolonged ESHP secondary to edema and altered metabolism. Therefore, we hypothesize that defining the changes in the metabolome during ESHP and the use of hemodialysis may improve heart function during prolonged ESHP. We have demonstrated the use of hemodialysis during ESHP significantly improves left ventricular and coronary vasomotor function. Furthermore, we have shown that carnitine synthesis is significantly impaired in both working mode and nonworking mode ESHP hearts.

Keywords: dialysis
Ex situ organ perfusion
metabolomics
organ perfusion
Advisor: Billia, Filio
Badiwala, Mitesh
An Educational Method for Learning and Assessing Interproximal Dental Caries Diagnosis in Bitewing Radiographs of Children

Background: Intraoral bitewing radiographs are the gold standard for diagnosing interproximal caries. There are currently no validated methods for assessing this competency in Canadian dental trainees. Objective: A computerized learning tool was developed to measure and improve performance in caries diagnosis from pediatric bitewing radiograph interpretation amongst dental trainees. Methods: In this multi-centre prospective cohort study, diagnostic performance was measured using learning curves and linear regression analysis identified image variables associated with increased interpretation difficulty of bitewing radiographs. Results: 62 participants completed the case set and a significant increase from mean initial to maximal diagnostic performance was observed (p<0.001). Two image-specific variables were associated with a significantly greater image interpretation difficulty score (p<0.001). Conclusion: The computerized learning platform led to effective and feasible skill improvement in diagnostic performance amongst dental trainees. Significance: The platform may be a valuable adjunct to existing educational methods in dentalradiology for dental trainees.

Keywords: caries diagnosis
computer-assisted instruction
dental education
educational measurement
performance-based learning
Advisor: Casas, Michael J
Design and Test Optimizations for Spacecraft Attitude Determination and Control Subsystems

As the demand for spacecraft grows, spacecraft manufacturers are required to innovate on system design and test procedures in order to meet demand. The University of Toronto Institute of Aerospace Studies (UTIAS) Space Flight Laboratory (SFL) thus requires innovative solutions to optimize the design and test of these spacecraft. This thesis presents four novel solutions to optimize both the Attitude Determination & Control System(s) (ADCS) design of new spacecraft and the test of related hardware. The test of ADCS hardware through software automation methods is explored, utilizing state-of-the-art software techniques to expedite testing procedures for the Hawkeye 360 constellation satellites. On-orbit inertia tensor estimation algorithms are also investigated, providing an alternative to model-based tensor calculations. Additionally, a novel method for repurposing an existing spacecraft inspection camera as a viable Earth Horizon Sensor (EHS) is exhibited. Lastly, automation methods for model-based spacecraft power generation analysis are demonstrated for the NASA StarBurst spacecraft.

Advisor: Zee, Robert E.
Targeting Acid Ceramidase to Attenuate Kidney Fibrosis

Chronic kidney disease (CKD) affects nearly 1 in 10 Canadians, a condition that in its end-stage has a worse prognosis than most cancers, and results in an annual healthcare cost of $40 billion. Despite fibrosis driving the progression of most forms of CKD, its pathogenesis remains poorly understood. Emerging evidence suggests the important role of acid ceramidase in regulating fibrosis across several organs, including the lung and liver. However, the role of acid ceramidase in the pathogenesis of kidney fibrosis remains largely unknown. Here we demonstrate that acid ceramidase mRNA is increased in fibrotic kidneys, and that inhibition of acid ceramidase with Carmofur reduces renal fibrosis. Furthermore, we provide evidence that acid ceramidase inhibition with Carmofur inhibits the activity of YAP and TAZ, two key pro-fibrotic transcription co-factors. Taken together, these data suggest that acid ceramidase inhibition might be a novel strategy to reduce kidney fibrosis.

Keywords: acid ceramidase
ceramide
chronic kidney disease
kidney fibrosis
Advisor: Yuen, Darren
A Social Equity Lens on Toronto Transit Network Performance using a Graph Theory Approach: Examining Criticality, Service Redundancy, Transit Delays and Disruptions

Public transit delays and disruptions are inevitable occurrences in many transit sys- tems. Past studies did not differentiate between different groups of riders when study- ing the disruption impacts and rarely integrated service frequency into their network models. This study adds a social equity layer by determining if different equity- seeking groups were more vulnerable to disruptions or had less resiliency than the general population.Various graph theory measures were used in the analysis, and both a time-expanded and an L-Space or route-map representations of the Toronto transit network were adopted. Census and travel demand survey data were used to determine trip patterns for the equity analysis. The results show that equity-seeking riders had slightly greater vulnerability and less redundancy in hypothetical scenarios of service disruptions compared to the gen- eral population. However, when analyzing real-world disruptions that occurred in 2019-2020, equity seeking riders were more resilient compared to the general population.

Keywords: Public Transit
Transit Delays
Transit Disruptions
Transit Equity
Transit Operations
Transportation Justice
Advisor: Shelby, Amer
Point Density-aware LiDAR 3D Object Detection for Autonomous Vehicles

LiDAR has become one of the primary 3D object detection sensors used in autonomous driving. However, LiDAR scans in autonomous driving datasets are often skewed and lack training data for objects at farther distances, resulting in a performance degradation as a function of range. Thus, we first introduce pattern-aware ground truth sampling, a data augmentation technique that uses the LiDAR's sampling pattern to simulate realistic objects at farther distances for better performance across range. Next, we explore different point cloud encoding methods for capturing point density variations in LiDAR data. Current methods largely ignore point density as a feature and its predictable relationship with distance from the LiDAR sensor. Our proposed solution, Point Density-Aware Voxel network (PDV), is an end-to-end two stage LiDAR 3D object detection architecture that explicitly accounts for these point density variations, outperforming other state-of-the-art detection methods.

Keywords: 3D Object Detection
Autonomous Vehicles
Data Augmentation
LiDAR
Point Cloud
Point Density
Advisor: Waslander, Steven L.
Real-time Location Data to Classify Degree of Cognitive Impariment and Motor Agitation

Real Time Location Systems can produce spatiotemporal data from people with dementia that might provide information about their cognition and health status. The first study explored a novel method to classify the severity of cognitive impairment (‘No-CI’, ‘Mild-Moderate CI’, ‘Severe CI’) among residents of a care unit using walking path images. The RTLS data was distributed into windows of various durations and transformed into images used in a Convolutional Neural Network that achieved a top accuracy of 87.38%. Class Activation Mapping was used to consolidate an objective score that can reliably distinguish between each class. The second study utilized features of spatiotemporal data with single-instance and multi-instance learning techniques in generalized and personalized models to detect low and high motor agitation. The top performing model achieved 0.71 with the Receiver Operator Characteristic in 5-fold cross validation with an indication that personalized models may require more data for improvement.

Keywords: Deep Learning
Dementia classification
Health monitoring technology
Machine Learning
Real-time Location Systems
Walking patterns
Advisor: Khan, Shehroz S
Monolithically Integrated Millimeter-Wave Spin-Qubit Control Circuits in FDSOI CMOS

This thesis investigates design considerations and topologies for spin-qubit control circuits integrated with qubits and readout circuits into one- and two-lane quantum processor test vehicles in a production 22-nm FDSOI process. The control circuits produce millimeter-wave pulses through direct modulation of an externally generated carrier in the DC-to-70-GHz and 140-to-160-GHz frequency ranges. At 2 K, one design featuring a shunt-series-shunt switch achieves 31.1 dB to 77.7 dB of on/off isolation from DC to 27 GHz, while another featuring a distributed switch achieves > 30.2 dB of on/off isolation at 2-46 GHz and 50-70 GHz. The standalone distributed switch shows > 34 dB of on/off isolation over 40-218 GHz at 295 K. These measurements demonstrate not only the possibility of minimizing qubit idling errors with the adopted switch topologies, but also the feasibility of the proposed elevated-temperature (1-7 K) monolithic quantum processor and methodology for designing cryogenic control circuits.

Keywords: FDSOI CMOS
integrated circuits
mm-wave
spin qubit
Advisor: Voinigescu, Sorin P.
Exploring the Importance of Candida albicans Lipid Metabolism Using Chemical Biology and Functional Genomic Approaches

Fungal infections represent a threat to human health with increasing rates of antifungal resistance impairing the utility of our antifungal arsenal. The opportunistic pathogen Candida albicans is a concerning fungal pathogen, exhibiting mortality rates of ~40%. We conducted a screen of 9,600 synthetic compounds from the University of Tokyo and identified CpdLC-6888 as possessing novel antifungal activity against C. albicans. The research presented in this thesis outlines the spectrum of activity of this compound against numerous fungal pathogens and establishes its impact on C. albicans morphogenesis. We determined CpdLC-6888 targets the ergosterol biosynthetic enzyme Erg11, the target of the azoles, despite structural differences between these two drugs. In parallel, I performed functional genomic analyses to explore the importance of lipid metabolic genes in growth, virulence, and antifungal tolerance in C. albicans. Overall, this project examines the importance of C. albicans lipid metabolism through chemical biology and functional genomic approaches.

Keywords: Chemical biology
Drug discovery
Fungi
Genomics
Infectious disease
Pathogens
Advisor: Cowen, Leah E
Very Long-chain Saturated Fatty Acids: Lifestyle Contributors and Associations With Pathophysiological Determinants of Type 2 Diabetes

Studies have reported that circulating very long-chain saturated fatty acids (VLCSFA), including arachidic acid (20:0), behenic acid (22:0), and lignoceric acid (24:0), are associated with a lower risk of type 2 diabetes mellitus (T2DM). This thesis aimed to identify dietary determinants of circulating VLCSFA in different serum fractions and evaluate their associations with insulin sensitivity and beta-cell function. We conducted a systematic review to summarize the current evidence on the lifestyle variables associated with circulating VLCSFA. Findings were used to support primary analyses conducted in the PROspective Metabolism Islet cell Evaluation (PROMISE) Cohort. Results indicated that healthier overall dietary quality was positively associated with triacylglycerol VLCSFA, and that VLCSFA in the triacylglycerol pool was longitudinally associated with improved insulin sensitivity and beta-cell function. Our data extend current evidence by indicating that the association between VLCSFA and T2DM may be mediated by changes in insulin sensitivity and beta-cell function over time.

Keywords: Diabetes
Epidemiology
Fatty acids
Advisor: Hanley, Anthony J
“Information is Power”: A Qualitative Study Exploring the Lived Experiences of Patients with Degenerative Cervical Radiculopathy

Degenerative cervical radiculopathy (DCR) leads to severe pain, paresthesia, and/or motor weakness, resulting in significant morbidity, disability, and reduced quality of life. The objective of this research is to understand the everyday experiences of individuals living with DCR, to help inform the development of a patient-centered non-operative program of care. A qualitative study conducted through an interpretivist lens explored the experiences of DCR through semistructured interviews. Participants describe significant physical and psychological impacts of symptoms, leading to disruption of their normal daily activities. Healthcare providers are seen as a cornerstone in patients’ journey with DCR, while family members provide substantial physical and emotional support. Expectations for a non-operative program of care include symptomatic relief and improved control of symptoms. The results of this project provide the first account of the everyday experiences of DCR patients and lay the groundwork for future steps to create a non-operative program of care.

Keywords: Cervical radiculopathy
Lived experiences
Phenomenological
Qualitative
Advisor: Ammendolia, Carlo
Hogg-Johnson, Sheilah