VictorJuiz/thesis huggingface dataset:
Structural Abnormalities of the Temporalis Muscle and Tendon in Temporomandibular Disorders
Keywords: Myalgia
Temporalis
Temporomandibular disorders

Myalgia of the masticatory muscles is the most common temporomandibular disorder (TMD). Although previous work has explored risk factors, and central and peripheral mechanisms of TMD myalgia (mTMD), the etiology of chronic mTMD pain remains poorly understood. This project aimed to determine whether chronic mTMD is associated with structural abnormalities of the temporalis muscle. We hypothesized that chronic mTMD is associated with a smaller aponeurosis-tendon complex (ATC) of the temporalis. T1-weighted magnetic resonance images of 34 chronic mTMD patients and 34 sex- and age matched healthy controls from two cohorts were studied. The volumes of the temporalis muscle and its ATC were measured via software. In both cohorts, mTMD patients had smaller ATC volumes than controls (all p
Training Caregivers to Reduce Spine Flexion using Biofeedback
Keywords: Back injury prevention
Biofeedback
Home caregivers
Posture
Wearable technology

Back injuries are extremely common among home caregivers due to the use of poor postures while performing daily tasks. Learning to use safer movement patterns may be accomplished with real-time biofeedback. The effectiveness of a two-day intervention - that includes biofeedback and a video - in decreasing time spent in end-of-range spine flexion was evaluated over a two-month period. 20 individuals with no caregiving experience repeated a series of simulated care tasks. Real-time auditory biofeedback was provided to the intervention group (n=10) when their sagittal lumbar spine flexion exceeded a threshold during training trials; the control group (n=10) received no feedback. Participants repeated the tasks again after two weeks and two months. The intervention group maintained decreased end-of-range (80th and 95th percentile) spine flexion compared to controls at both time points. Group performances on box lifting technique, a skill transfer task, and a back-injury prevention questionnaire were also compared.
Development and Evaluation of a Navigation Workflow for Radiofrequency Ablation of Spinal Metastases
Keywords: Bone-targeted Radiofrequency ablation
image registration
procedural navigation
Spinal metastases
treatment planning

Bone metastases present in more than 85% of cancer patients at the time of death, with the spine being the most common site. Improvements in radiofrequency ablation (RFA) has adapted this technology for local control of spinal metastases. In this thesis, a navigation workflow for vertebral RFA was developed utilizing software to integrate pre-procedural imaging data with RFA treatment plans and intra-procedural imaging data. An optical tracking camera is utilized to track the RFA probe intraoperatively and to ensure that the final pose matches the prescribed pose. The feasibility of the workflow was evaluated by two spine surgeons in animal studies. The accuracy of the navigation was also tested in phantom and animal models. The developed software yields a clinically feasible workflow similar to the existing systems adopted in procedure rooms. Navigated RFA may improve the safety and efficacy of this procedure, and ultimately enhance quality of life for patients.
Photodynamic Therapy of Pancreatic Cancer with Porphyrin-lipoprotein Photosensitizers
Keywords: Animal models
Nanomedicine
Pancreatic cancer
Photodynamic therapy
Porphyrin-lipid
Theranostics

Previously, the high-density lipoprotein (HDL) mimicking porphyrin-lipoprotein (PLP) nanoparticle was found to accumulate more in tumours compared to their non-cancerous counterparts in several clinically relevant animal models. PLP demonstrates stability in blood circulation and rapid dissociation upon tumour accumulation to generate fluorescence and photodynamic reactivity. Photodynamic therapy (PDT) has been tested in pancreatic cancer patients with clinically approved photosensitizers; however, none are tumour selective. In this work, using in vitro tests with pancreatic adenocarcinoma cell line (PANC-1) and subcutaneous PANC-1 xenograft and orthotopic PANC-1 mouse models in vivo, it was demonstrated that PLP uptake more in pancreatic tumours compared to non-cancerous tissue. In addition, PLP combined with PDT (PLP-PDT) was effective in tumour destruction in vitro and in chronic studies with the subcutaneous PANC-1 xenograft mice. With the orthotopic PANC-1 mouse model, PLP-PDT treatment induced significantly more damage at the tumour site compared to non- cancerous pancreatic tissue.
Baseline Toronto HCC Risk Index (THRI) and Albumin Predict Low Risk of Hepatocellular Carcinoma (HCC) after Sustained Virological Response (SVR) in HCV Infection
Keywords: Hepatitis C
Hepatocellular carcinoma
Sustained virological response

Current guidelines recommend hepatocellular carcinoma (HCC) surveillance for patients with F3/F4 fibrosis after sustained virological response (SVR) with treatment for hepatitis C infection, however not all patients are at equally high risk for HCC. We aimed to identify factors associated with a low enough risk for HCC to forego ongoing surveillance. Patients with F3/F4 fibrosis and SVR were included. Data were collected at start of treatment and Toronto HCC risk index (THRI) combining age, sex, and platelets was calculated. Patients were followed from end of treatment until first HCC occurrence. Of 1,131 patients, 50 (4%) developed HCC over median (IQR) 1.9 (0.6-3.8) years. On multivariable Cox regression, baseline THRI≥160 (HR=2.71, P=0.001) and albumin≤40 g/L (HR=3.05, P=0.001) predicted increased HCC risk. Among hepatitis C patients with F3/F4 fibrosis and SVR, patients with baseline THRI
Elucidating the Regulatory Role of PHIP1 in Activated T Cell Metabolism and Immunity
Keywords: Gene regulation
Immunometabolism
PHIP1
T cell activation
T cells

Metabolic and transcriptional pathways in T-cells are intricately woven to affect cell fate decisions and functions downstream of T-cell activation. We proposed that an understudied epigenetic and transcriptional co-regulator previously implicated in insulin signaling, growth and aerobic glycolysis, PHIP1, could provide further means to explore the crosstalk between metabolism and gene regulation in coordinating T-cell responses. We found that upon activation, PHIP1 is significantly upregulated in T-cells and demonstrates both nuclear and cytoplasmic expression, but almost exclusively localizes in the nucleus during quiescence. PHIP1-siRNA-mediated knockdowns showed that PHIP1 regulates critical genes involved in T-cell metabolism, survival and effector/memory formation, for optimal transcriptional remodeling during activation. Data trends indicate memory-specific inhibition and/or preference for effector-like responses in PHIP1-deficient T-cells, although additional in-depth studies are required to confirm this. Further investigations can potentially implicate PHIP1 as a novel candidate to reprogram T-cell metabolism and differentiation and thus enhance or temper cellular immunity.
Peptide-based Approach toward the Inhibition of a Bacterial Multidrug Resistance Efflux Pump
Keywords: AcrB
Antibiotic resistance
efflux
efflux pump inhibitor
peptide
RND

Efflux proteins allow multidrug resistant bacteria to pump out antibiotics before they can exert their toxic effect(s). The E. coli membrane protein AcrB is the archetypal member of the most efficient superfamily of efflux pumps. Since AcrB forms a trimer in order to properly function, we have proposed to inhibit AcrB using a novel strategy in which synthetic peptides are designed to mimic the transmembrane (TM) oligomerization interface and thus outcompete the critical helix-helix contacts. In this thesis, we demonstrate that peptides designed from the AcrB TM1/TM8 interaction site inhibit efflux of an AcrB fluorescent substrate as well as allow current antibiotics to work more effectively. Biophysical analysis confirmed the partitioning of the peptides into membranes. Systematic variations in the peptide sequences highlighted key functional helix-helix interactions that are likely to stabilize the AcrB trimer. This work represents a foundation for developing a peptide-based inhibitor against the protein.
Inequities in Black et Blanc: Textual Constructions of the French Immersion Student
Keywords: bilingualism
education
French as a second language
French immersion
sociolinguistics

This thesis is an investigation into Toronto and Ontario French immersion policy, curricula, and other related documents in order to understand if and how current documents contribute to the over-representation of White middle-class students in French immersion. The study found that French immersion policies, curricula, and documents evidenced a middle-class bias due to lack of resources, transportation and promotional materials, and location of programs. It had a White bias through its Eurocentric curricular content. The documents of this study also privileged English above all other languages, and families who were not newcomers. The documents did not entirely mirror the population in French immersion in terms of gender, home language and special education needs. Equity documents highlight that steps are being taken toward a more inclusive immersion program, but there is still much to do, especially in terms of dismantling and transforming hierarchies.
Identifying Chemical Modulators of C. elegans Stress Response for Use as Tools and Potential Anthelmintics
Keywords: Drug discovery
Drug screen
Genetic screens
Model organism
Parasitic helminths
Synthetic lethality

Parasitic nematodes currently plague around two billion people. Resistance has developed against nearly all anthelmintic classes in agriculture. Towards identifying novel anthelmintic, we proposed that if nematode stress response mechanisms are chemically inhibited in stressful conditions, affected animals would become more susceptible to killing by stressors encountered during their lifecycles. From literature, we identified GFP reporters of canonical stress response pathways. I screened our custom worm active library of 485 unique structures with C. elegans and identified 18 compounds that suppress elicited reporters and/or exert synthetic lethality in stressful conditions. Wact-128 and wact-204 were identified as promising hits. They suppress elicited oxidative stress response and kill synthetically with oxidative stress. Through characterization of their mechanism of actions, I found evidence for wact-128 and wact-204’s inhibitory activity on the SKN-1-mediated oxidative response pathway. Chemicals that selectively inhibit nematode’s SKN-1-mediated pathway may be developed into novel anthelmintic or adjuvants for existing anthelmintic.
Familial Aggregation of Executive Functioning in Borderline Personality Disorder
Keywords: borderline personality disorder
cognition
executive functioning
familial aggregation
impulsivity
phenotype

Borderline personality disorder (BPD) is a psychiatric disorder characterized by impulsivity, emotional dysregulation, and deficits in executive functioning (EF), but the extent to which EF deficits runs in BPD families remains poorly understood. The current study examines the multivariate familial aggregation of EF indices in probands with BPD, first-degree biological relatives, and healthy controls. Discriminant function analyses reveal that interference resolution and response inhibition performance are key to discriminating BPD probands from relatives and controls, while a pattern of less efficient problem solving and difficulty manipulating mental information discriminates probands and relatives from controls. Moreover, psychiatrically nonaffected relatives demonstrate a pattern of resilience to familial psychiatric risk, substantiated by stronger response inhibition and abstraction abilities despite less efficient problem solving. Future research should explore the associations between EF and maladaptive trait dimensions—like impulsivity and emotional dysregulation—to advance dimensional conceptualizations of psychopathology and elucidate the BPD phenotype.
Pharmacological Mechanisms of Interhemispheric Signal Propagation and its Disruption in Schizophrenia and Depression
Keywords: Corpus Callosum
Depression
Electrophysiology
Schizophrenia
TMS-EEG
Transcranial magnetic stimulation

Altered interhemispheric connectivity, linked to deficits of gamma-aminobutyric-acid (GABA) neurotransmission and transcallosal microstructure, is implicated in the pathophysiology of schizophrenia (SCZ) and major depressive disorder (MDD). Objectives: First, we investigated the neurochemical mechanisms of interhemispheric signal propagation (ISP) using combined transcranial magnetic stimulation and electroencephalography (TMS-EEG) with pharmacological modulation in healthy participants. Next, we assessed differences of TMS-evoked ISP between SCZ, MDD, and healthy participants. Hypothesis: It was predicted that ISP would be selectively modulated by the GABAB receptor agonist baclofen and altered in SCZ patients only. Results: Baclofen was the only pharmacological agent that altered and reduced ISP. Additionally, ISP was elevated in both SCZ and MDD patients compared to healthy participants. Conclusions: ISP is modulated by GABAergic neurotransmission and altered in SCZ and MDD. This provides a fundamental step to characterize the mechanisms of TMS-evoked ISP and identify treatments for disorders in which transcallosal signal transmission is dysfunctional.
Modulation of Jaw Muscle Motor Response with Music in Individuals with Muscular Temporomandibular Disorders
Keywords: Bruxism
Guided music listening
Oral behaviours
Surface electromyography
Temporomandibular disorders
Wake-time tooth clenching

Oral behaviours, such as wake-time tooth clenching and awake bruxism, are strongly associated with mood disorders, and are risk factors for temporomandibular disorders (TMD). Guided Music Listening (GML), a complimentary therapy based on mood mediation, reduces anxiety and depression in patients with chronic pain. This study tested the effects of GML on wake-time tooth clenching in individuals with chronic TMD myalgia (mTMD). The electromyographic (EMG) activity of the right masseter of fourteen women with mTMD and fifteen TMD-free controls was recorded during three music (stressful, relaxing, and favorite) and a control (pink noise) tasks. GML affected the EMG amplitude of the masseter in both groups (all p
Vertical Transmission of HIV: Comparison of Policies in North and Sub-Saharan Africa
Keywords: Algeria
Comparative policy
HIV
Senegal

This project aims to investigate the extent to which differences in the design of national prevention of mother to child transmission policies and strategies between North Africa and Sub-Saharan Africa help to explain differences in vertical transmission rates between these two regions. To do so, I selected two case countries, one from each region, and conducted a qualitative document analysis of their HIV prevention policies since 2010, guided by two theoretical frameworks, the Analysis of Determinants of Policy Impacts (ADEPT) model of health promotion and the Health Policy Triangle. This project has revealed the importance of 1) civil society organizations in HIV prevention, 2) sufficient monitoring and evaluation systems and 3) the involvement of Intergovernmental Organizations (IGOs) in the strategic financing of HIV prevention strategies in low- and middle-income countries.
Mothers’ Oral Health Status and its Relationship to Severe Early Childhood Caries (S-ECC) in an Indigenous Population in Canada
Keywords: dental caries
Early childhood caries
Indigenous
maternal oral health behaviors
oral health
self-efficacy

Objective: To determine the relationship between Indigenous mothers’ oral health status and severe early childhood caries (S-ECC) in their children and to examine whether mothers’ oral health-related self-efficacy (OHSE) mediates this association. Methods: The study included 544 Indigenous pregnant women in Canada, who underwent a clinical examination and completed a survey. Their children underwent a clinical examination when they were 2 years old. Results: After adjusting for mother’s age, smoking status, area of residence (on First Nations reserve or off reserve) and OHSE using logistic regression, Gingival Index (Odds Ratio 3.2, 95% Confidence Interval 1.5–6.6) and Debris Index (OR 2.4, 95% CI 1.3–4.7) were significantly associated with S-ECC. In the mediation analysis, maternal oral health status measures were negatively associated with OHSE and had a direct effect on S-ECC. Conclusions: Clinical normative measures of Indigenous mothers’ oral health status were significant determinants of S-ECC in their toddlers.
Risk of Any Hypoglycemia with New Antihyperglycemic Agents in Patients with Type 2 Diabetes: A Systematic Review and Meta-analysis
Keywords: antihyperglycemic agents
diabetes
hypoglycemia
meta-analysis

Background: Evaluation of hypoglycemia risk relative to placebo with new antihyperglycemic agents (AHA) including the dipeptidyl peptidase-4 inhibitors (DPP4i), glucagon-like peptide-1 receptor agonists (GLP1RA) and sodium-glucose co-transporter-2 inhibitors (SGLT2i) remains inconclusive. Objective: This systematic review and meta-analysis aimed to assess risk of any and severe hypoglycemia with new AHA relative to placebo by excluding studies with background sulfonylureas and insulin. Methods: Randomized, placebo-controlled studies, 12 weeks or greater in duration were considered for inclusion. Studies allowing background use of any other AHA, apart from metformin, were excluded. This study is registered with PROSPERO (CRD42018095458). Results: 141 studies included in the meta-analysis demonstrate that relative to placebo, risk of any and severe hypoglycemia did not significantly differ for any new AHA.
Design, Development, and Testing of the Command and Data Handling Subsystem for Microsatellite Missions
Keywords: Command and Data Handling
Microsatellite
NEMO-HD
NorSat-3
Satellite
Software

A spacecraft is composed of multiple subsystems that work together to accomplish the mission objectives. One of the most vital subsystems is termed the “brain” of the spacecraft, more formally known as the command and data handling subsystem, which is responsible for commanding all other subsystems and managing all data sent and received by the spacecraft. This thesis describes the author’s contributions to the various aspects of the command and data handling subsystem for two microsatellite missions, with focus on work that can be extended for use and implemented on future space missions at the Space Flight Laboratory. Particular emphasis is given to the author’s work on design of a new serial interface board, optimization of both ground and satellite software related to payload data handling, and development of various application threads on satellite on-board computers and ground control interfaces.
Opioid Prescribing after Surgery among Chronic Opioid users in Ontario: A Population-based Cohort Study
Keywords: Anesthesiology
Opioids
Pain

Patients who chronically use opioids may undergo surgery; it is unclear if surgery alters the trajectory of opioid consumption in these patients. We sought to determine if exposure to surgery is associated with opioid discontinuation among chronic users, and factors associated with opioid discontinuation after surgery. The study included 4,755 surgical and 14,265 matched non-surgical patients with chronic opioid use. After adjusting for patient characteristics, surgery was associated with an increased likelihood of opioid discontinuation (aHR: 1.34 95%CI: 1.27, 1.42). Among surgical patients, factors associated with a reduced odds of discontinuation included a mean preoperative opioid dose >90 morphine milligram equivalents (aOR: 0.39 95%CI:0.31, 0.49), preoperative oxycodone prescriptions (aOR: 0.74 95%CI:0.55, 0.98), and a diagnosis of chronic obstructive pulmonary disease (aOR: 0.75 95%CI: 0.64, 0.88) or dementia (aOR: 0.58 95%CI: 0.37, 0.91). Further research is needed to evaluate interventions that can influence post-operative opioid discontinuation, particularly in high risk patients.
Minimizing the Completion Time of Distributed Learning Workloads via Deep Reinforcement Learning
Keywords: Deep Reinforcement Learning
Distributed Learning

Large-scale machine learning models are routinely trained in a distributed fashion due to their increasing complexity and data sizes. Distributed learning is therefore proposed to reduce the completion time of a machine learning workload by leveraging parallelism. However, distributed learning workloads are time-consuming and resource-intensive in general. Consequently, we study the problem of minimizing the completion time of distributed learning workloads under two different settings within this thesis. The first is a shared cluster handling multiple distributed learning workloads with a parameter server framework, while the second is a distributed learning method called Federated Learning. Inspired by the recent advances in deep reinforcement learning, we use an experience- driven approach to solve these two problems. Our extensive array of simulation results have shown clear evidence of the effectiveness of our proposed methods.
Impact of Air Pollution on Respiratory Infection in Healthy and Cystic Fibrosis micP
Keywords: Air pollution
Cystic fibrosis
Respiratory infection

Pulmonary infections are a significant cause of morbidity and mortality in patients with cystic fibrosis (CF). Increased pollution level is associated with hospitalization due to respiratory infection, as well as pulmonary exacerbation and earlier acquisition of airway bacteria in CF patients. To validate these findings, we investigated the effect of in vivo inhalation exposure of traffic pollutants on the subsequent Pseudomonas aeruginosa and Staphylococcus aureus lung infection in C57BL/6J and CFTR knockout mice. Prior pollution exposure increased severity of the subsequent lung infection, with an augmented inflammatory response that demonstrated impaired bacterial clearance with decreased lung myeloperoxidase activity. These changes were associated with upregulated pulmonary inflammatory genes Il17a, Cxcl1, Tnf, Il6 and Il1b, as well as altered redox signaling pathways. Our data provide evidence that air pollution is a significant environmental risk factor to respiratory infections, particularly in susceptible populations such as CF patients.
Development of a Quadrotor Slung Payload System
Keywords: Landing
Quadrotor
Slung Payload
UAV

In this work, a quadrotor unmanned aerial vehicle is investigated for the task of a slung payload delivery. A simplified guidance law is proposed to address the problem of autonomous landing with a slung payload. In addition, a complete development framework is presented. This includes a generic dynamic model for the slung payload system, a simulation environment, and an experimental platform, capable of completing the mission. This framework is used to assess the feasibility of the proposed approach and validate it through flight tests. The proposed guidance law is compared to a controller without guidance, both in simulation and in experimental flight tests. It was found that the guidance law achieved a smooth trajectory with minimal payload swing during the autonomous landing mission segment.