VictorJuiz/thesis huggingface dataset:
A Lower-body Exoskeleton Simulation and Control Framework based on Deep Reinforcement Learning

Stroke is a leading cause of disability, and post-stroke individuals often experience hemiparesis, which can result in compensatory movements that affect their overall gait pattern. Lower-body exoskeletons allow for repetitive, intense, and task-based practice of movement patterns that can promote gait recovery. Validating exoskeleton gait patterns in simulation is vital for ensuring patient safety and comfort; however, current simulation tools possess challenges in controlling exoskeleton hardware. Additionally, present model-based adaptive controllers rely on complex dynamics models for the user and exoskeleton that are difficult to accurately define. In this thesis, a centralized exoskeleton simulation and control framework is presented, where desired gait patterns can be validated and customized on-the-fly in physiotherapy sessions. A model-free, end-to-end deep reinforcement learning controller is also presented, to allow for exoskeleton control that is robust to desired gait patterns and a user's interaction with the device. Several experiments were conducted to validate these approaches.

Keywords: Biomechanics
Deep Reinforcement Learning
Lower-body Exoskeletons
Post-stroke gait rehabilitation
Advisor: Nejat, Goldie
Characterizing Head and Eye Movements used to Compensate for Impaired Biaural Hearing through Unilateral Plugging

The primary objective of this thesis was to characterize the magnitude and time course of natural head and eye movements during auditory localization in the azimuthal plane when binaural hearing is impaired. Towards this aim, thirty-three youth and adults with typical hearing were testing using a novel moving speaker arm set-up which presented stationary and moving sounds within an arc of 120. Testing was completed under normal conditions and was subsequently repeated in an acute unilateral ear plugging scenario. Primary findings were as follows: localization accuracy and precision were found to be excellent under normal conditions but declined during ear plugging, head and eye movements revealed that under normal conditions, movements were biased towards the target location and eye movements led head movements, whereas during plugging head movements were biased towards the side of the plugged ear suggesting an adaptation to reduce the head shadow.

Keywords: Binaural Hearing
Compensatory Movements
Eye Movements
Head Movements
Sound Localization
Spatial Hearing
Advisor: Gordon, Karen A
Influence of Nitrogen on Deuterium Retention in Polycrystalline Tungsten under Sequential and Simultaneous Irradiation

Nitrogen is a candidate for impurity seeding to reduce the edge plasma temperature for ITER's tungsten divertor. Radiation characteristics and plasma performance are improved with N compared to other candidates neon and argon, however questions remain in terms of how the introduction of N might impact deuterium retention in W. The current study compares the influence of N on D retention in W with sequential (SEQ) and simultaneous (SIM) irradiation of D-3%N at 300-700 K with energies 500 eV/D^+ and 1000 eV/N^+. Thermal desorption spectroscopy (TDS) is used to measure the D retained, and x-ray photoelectron spectroscopy (XPS) is used to investigate nitride formation at different implantation temperatures. The observed effect of the N-containing layer on the temperature dependence of deuterium retention during TDS suggests that the stoichiometry of the W:N layers produced are different at different temperatures. It is found that SIM irradiation resulted in a small overall increase in total D retention compared to SEQ and D-only experiments above 500 K. At 300 - 500 K, the D retention was not significantly changed by nitrogen pre-, post- or simultaneous irradiation.

Advisor: Davis, James W
PKCδ Regulates Actomyosin Organization in Leading Cellular Protrusions during Drosophila Border Cell Migration

Actin-based membrane protrusions are essential for cell migration, including the collective migration of the border cell cluster (BCC) during Drosophila oogenesis. Our lab previously showed that the serine/threonine kinase Protein Kinase C δ (PKCδ) regulates the structure and behavior of the leading protrusion of the BCC. Here, I investigated the influence of PKCδ on the actomyosin network of BCC protrusions. Examination of PKCδ loss-of-function mutants revealed that PKCδ is required for normal F-actin organization and Myosin II (MyoII) distribution in protrusions. Overexpression of PKCδ caused a severe reduction in actomyosin in protrusions. Moreover, PKCδ prevents simultaneous formation of multiple leading protrusions. Rho1, a positive upstream regulator of MyoII, appears to be activated in the leading protrusion precociously when PKCδ function is lost. In summary, my analysis contributes to our understanding of the function of PKCδ as a regulator of the actomyosin network in leading cellular protrusions during collective cell migration.

Keywords: Actomyosin dynamics
Border cell cluster
Cellular protrusions
Collective cell migration
Confocal microscopy
PKCδ
Advisor: Godt, Dorothea
Finite Element Modelling of Ultra-high Performance Fibre Reinforced Concrete

Ultra-high performance fibre reinforced concrete (UHPFRC) is a relatively new material showing increased use for practical engineering problems. Although significant research has been undertaken in the development of constitutive models for the finite element modelling of steel fibre reinforced concrete (SFRC), the reliability of these models in analyzing UHPFRC remains unassessed. This thesis outlines the investigation of these models in finite element software VecTor2 for their applicability in analyzing UHPFRC. Localized behaviour at cracks was investigated, leading to improvements in current crack spacing formulations through the inclusion of an effective aggregate size for UHPFRC. An embedded steel reinforcement rupture formulation for specimens subjected to tension was also implemented to predict reinforcement rupture strains of reinforced concrete specimens. Finally, studies were conducted to validate these models for structures subjected to various loading effects by comparing the finite element simulations with experimental results found in the literature.

Keywords: Fibre Reinforced Concrete
Finite Element Modelling
Ultra-High Performance Concrete
VecTor2
Advisor: Vecchio, Frank J
Exploring Ecologies of the Heart: a Pedagogy for Healing

Throughout this work I outline the crucial role education plays in developing students’ capacities to lead a good life. Without an awareness of the nature of life as interdependent, the mind as self-deceptive and spirit as all encompassing, students are shielded from their capacity to emancipate from cognitive distortions and attune to the healing potential of nature. Without the engagement of contemplative practice from which ecologies of the heart can emerge to cultivate meaning and significance in life, education remains confined to recreating relationships of disconnect and contributing to a colonialist cycle of trauma and self-destruction. The entangled relationship between declining ecological diversity and student mental health and well-being reveals a problem with education. This problem is argued to be grounded in the narrative of human-nature duality (Orr, 2013; Louv, 2011; Zylstra et al., 2014).

Keywords: ancient knowledge
educating the soul
emotions
holism
human-nature
re-indigenization
Advisor: Miller, John P
Outcomes in Pulmonary Hypertension Among Adults Undergoing Percutaneous Atrial Septal Defect Closure

Atrial septal defects (ASDs) are one of the most common forms of congenital cardiac lesions diagnosed during adulthood. If left untreated, ASDs can lead to right ventricular failure and pulmonary hypertension (PH). Patients with PH and ASD suffer from worse prognoses than patients without PH. The role of ASD closure and its effects on PH remain unclear and information regarding the relationship between ASD closure and PH is limited. The first objective of this thesis was to synthesize the current body of ASD with PH literature through a systematic review and meta-analyses. Our second objective was to produce a high-quality cohort study assessing long-term outcomes of ASD closure between patients with and without PH. We found that PH prevalence and mean pulmonary arterial pressure decrease after ASD closure. Our analyses found that ASD patients with PH undergoing closure experience more comorbidities and worse long-term outcomes, compared to patients without PH.

Keywords: Atrial Septal Defects
Health Service Research
Interventional Cardiology
Outcomes and Evaluation
Pulmonary Hypertension
Advisor: Abrahamyan, Lusine
Horlick, Eric
Maintenance and Reliability Models for a Public Transit Bus

Public transit buses are an essential part of modern society and are prone to frequent breakdowns. The goal of this research is to develop an opportunistic maintenance policy that maximizes bus availability. A transit bus is composed of over 10 000 components which can be classified into modules based on their location and function in the bus. A reliability model considering imperfect repair is developed using real transit bus failure data to identify the components that have the largest impact on bus availability. A method to find the maintenance policy that maximizes the availability of a bus module is developed using the semi-Markov decision process framework. Discrete event simulation is used to find an opportunistic maintenance policy that maximizes the availability for an entire transit bus. The developed maintenance policies are compared with the conventional maintenance practice of repairing only on failure.

Keywords: Maintenance
Opportunistic
Reliability
Semi-Markov Decision Process
Simulation
Transit Bus
Advisor: Makis, Viliam
The Effects of Exercise and Osteocalcin on Metabolism, Behaviour and Cognition of Female Mice Fed Either a Low-fat or High-fat Diet

Osteoblast-derived osteocalcin (Ocn) is implicated in the endocrine actions of the skeleton in modulating cognition, mood and energy homeostasis. Here we compared the effects of daily treadmill exercise, 30 ng/g/day Ocn administration, or the combination of both in female C57Bl/6J mice fed either a low-fat or high-fat diet. Weight gain from high-fat diet was decreased and glucose tolerance improved by exercise with or without Ocn but not by Ocn alone. Exercise, osteocalcin and their combination alleviated the depressive-like but not anxiety-like behaviours induced by a high-fat diet. Cognitive deficits induced by high-fat diet were reversed by exercise or Ocn, with combined treatment having the greatest effect. Under normal metabolic conditions, neither exercise nor Ocn altered behavioural responses. Together, these results suggest that exercise is more effective in improving metabolism while osteocalcin or exercise are effective in treating cognitive deficits and depressive-like behaviours caused by high-fat diet.

Keywords: Behaviour
Cognition
Osteocalcin
Type 2 Diabetes Mellitus
Advisor: Mitchell, Jane
Swardfager, Walter
Reimagining the Operating Room Inventory as a Center of Savings

Operating room inventories typically manage hundreds of surgical items. Currently most inventory managers rely on intuition to set inventory control parameters. Even when they have access to software that automatically sets inventory policies using classical methods, they rely on assumptions that do not accurately represent typical operating room inventories. We investigate the value of ordering policies improved with access to information on usage and lead time patterns and upstream visibility. A search strategy and discrete event simulation are used to analyze the cost effectiveness of automatically setting inventory control parameters when considering the real-world environment. Results show inventory policies generated based on the real environment which acknowledge usage patterns and take advantage of upstream visibility lead to cost savings when compared to expert intuition and classically proposed policies. We provide realistic actions hospitals can take to decrease disposable surgical supply inventory policy costs.

Advisor: Carter, Michael
Investigating the Role of the Ventral Hippocampal CA1 and CA3 in Approach-avoidance Conflict using Fiber Photometry

Approach-avoidance conflict occurs when an organism encounters a stimulus that is imbued with both positive and negative valences and must choose to either approach or avoid this scenario. Converging evidence supports the role of the ventral hippocampus (vHPC) in the resolution of such forms of conflict. This thesis aimed to further elucidate the contributions of the vCA1 and vCA3 subregions of the vHPC in conflict resolution processes using fiber photometry. To achieve this, genetically encoded calcium indicators (GECIs) were virally introduced into the vCA1 or vCA3 and calcium activity was subsequently recorded through an optic fiber. Using a Y-maze paradigm, animals were trained to associate three distinct visuo-tactile cues with either an appetitive, aversive, or neutral outcome. Post-acquisition, animals underwent a cued conflict task in which a neutral and conflict arm (appetitive and aversive cues superimposed) were presented. Neuronal recordings revealed dissociable activation of the vCA1 and vCA3 during approach and avoidance of the conflict arm, respectively.

Keywords: Anxiety
Approach-avoidance conflict
Decision making
Fiber photometry
Rat
Ventral hippocampus
Advisor: Ito, Rutsuko
Body Representation of Bodies with Absent Limbs

Self-other interactions are facilitated through the activation of the body schema – a representation of one’s body is used as a reference to map others’ bodies. Here, the body-part compatibility effect was used as an index of self-other matching. The body-part compatibility effect describes the finding that there are shorter response times to targets presented on an observed limb that is homologous to the responding limb than when the observed and responding limbs are non-homologous. This compatibility effect was investigated as participants viewed bodies with hidden or visible limbs (Experiment 1) and missing or intact limbs (Experiment 2). Compatibility effects were present when viewing hidden and visible limbs (Experiment 1), whereas the compatibility effect was only present for both responding limbs when viewing the missing legs (Experiment 2 preliminary). Overall, the results indicate that self-other matching may be reduced when the limbs of the model are hidden behind an object.

Keywords: Body Representation
Body Schema
Body-Part Compatibility
Hidden limbs
Missing limbs
Self-other matching
Advisor: Welsh, Timothy N
Saturation Transfer Neuroimaging Features of Sickle Cell Anemia

The broad symptomatology of sickle cell anemia (SCA) includes severe neurologic complications, such as stroke and cognitive impairment, from a young age in many patients. Evidence suggests that chronic oxygen deprivation leads to alterations in cerebral blood flow, metabolism, and tissue microstructure which contribute to neurologic morbidity. We have proposed that saturation transfer MRI, an imaging modality sensitive to the microstructure and biochemical environment of tissues, could improve our understanding of neurologic pathology in SCA and have potential clinical utility for assessing disease severity. This thesis reports on a preclinical study to characterize saturation transfer neuroimaging features in a mouse model of SCA. The results of this study demonstrate that saturation transfer MRI is sensitive to microstructural and metabolic alterations in the normal-appearing grey matter of SCA mice. These findings warrant further investigation into saturation transfer neuroimaging as a research tool and a clinical biomarker of brain injury in SCA.

Keywords: CEST
Magnetization Transfer
MRI
Saturation Transfer
Sickle Cell Anemia
Sickle Cell Disease
Advisor: Sled, John G
Modular UHPFRC Waffle Deck Slabs For Highway Bridges

This thesis examines the design of an Ultra High Performance Fibre Reinforced Concrete (UHPFRC) bridge deck for use in slab on girder highway bridges. The deck will be assembled from prefabricated panels and on-site closure pours. Each panel will consist of a thin, unreinforced slab cast monolithically with an orthogonal gird of reinforced ribs – a system sometimes called a waffle slab. Using a linear elastic grillage model of the system, a preliminary design of rib sizing, reinforcing and post-tensioning was developed. This was followed by physical tests on unreinforced slabs to determine the optimal combination of slab thickness and rib spacing. Results were analyzed using the yield line analysis method and novel developments for applying yield line analysis to UHPFRC specimens were explored. The thesis concludes with a discussion about the next test – a test of full scale, small size specimens with final candidate dimensions with and without post-tensioning.

Keywords: Bridges
UHPFRC
Waffle Deck Slabs
Advisor: Gauvreau, Paul
Task-relevant Perceptual Comparisons Induce Lasting Memory Distortion

While retrieving a memory facilitates its future accessibility (i.e., testing effect), novel information present at the time of retrieval can distort memory content (e.g., misinformation effect). However, it is unclear what cognitive mechanism is responsible for driving these undesired changes to memory. Here, I tested the role of subjective similarity judgments that individuals make when comparing a retrieved memory representation to a novel perceptual input. Following similarity judgments, younger adults reliably reported systematic memory biases in real-world objects that were maintained in working memory (n = 32) or recalled from long-term memory (n = 30). These biases were larger in consolidated memories than recently-encoded memories and persisted when participants maintained high confidence in the accuracy of a biased memory. These findings suggest that subjective similarity judgments plausibly account for longstanding memory distortion phenomena.

Advisor: Fukuda, Keisuke
Fukuda, Katherine
Developing Small Molecule Inhibitors of ALK2: A Serine/Threonine Kinase Implicated in Diffuse Intrinsic Pontine Glioma

Diffuse intrinsic pontine glioma (DIPG) is an aggressive pediatric cancer for which no effective chemotherapeutic drugs exist. Analysis of the genomic landscape of this disease has led to the identification of the serine/threonine kinase ALK2 as a potential target for therapeutic intervention. In this work, we developed two separate series of potent type I inhibitors of ALK2 based on the previously reported inhibitor LDN-214117. The first structure-activity relationship (SAR) study focuses on improving the selectivity, permeability and pharmacokinetic profile of M4K2149, a benzamide analogue with reduced off-target affinity for the hERG potassium channel. The second part of this thesis highlights the efforts made to develop a conformationally constrained inhibitor that was rigidified into the biologically active configuration of M4K2009, the lead compound of this project. Future studies will assess the permeability of select compounds in a Caco-2 permeability assay and their PK profiles in vivo.

Advisor: Al-awar, Rima
G-protein Signaling Regulating Opioid-induced Respiratory Rate Depression

Opioids are pain treatment mainstays, but present with potentially lethal respiratory depression. To develop safer opioid therapies, mechanisms underlying opioid-induced respiratory depression must be better understood. Opioids mainly bind to µ-opioid receptors (MORs), Gprotein-coupled receptors that activate heterotrimeric G-proteins, including Gβγ. There is significant debate around whether G-proteins or β-arrestins, proteins involved in receptor internalization/desensitization, directly regulate respiratory circuit inhibition. While Gβγ activates G-protein inwardly rectifying potassium (GIRK) channels, which are key mediators of respiratory rate depression, its direct role in opioid-induced respiratory depression is unknown. We investigated the contribution of Gβγ in opioid-induced respiratory rate depression and found Gβγ inhibition in respiratory circuits reversed opioid-induced respiratory rate depression, regulators of G-protein signaling 4 (RGS4) are co-expressed with MORs in respiratory circuits, and RGS4 inhibition in vivo potentiates opioid-induced respiratory rate depression. Our data suggest G-protein signaling is key in opioid-induced respiratory depression and is not limited to β-arrestin recruitment.

Keywords: Opioid
PreBotzinger Complex
Respiratory Depression
RGS
Advisor: Montandon, Gaspard
Development of a Core Outcome Set for Studies on the Prevention and Management of Pregnancy-associated Venous Thromboembolism

Background: The objective of this thesis was to identify a list of outcomes to consider in the development of a core outcome set (COS) to inform future studies on pregnancy-associated venous thromboembolism (VTE), with aim of standardizing outcome reporting. Methods: We conducted a systematic review (Study-1) of 70 studies and 18 interviews (Study-2) with health service users and healthcare professionals, to generate a list of outcomes and inform a two-part online Delphi survey (Study-3). Results: Studies-1 and 2 identified 35 and 57 outcomes, respectively, which were condensed to 45 unique outcomes. The Delphi survey included 81 participants in round-1 and 66 in round-2 including health service users, clinicians and academics, representing 21 countries. Conclusion: We have attained consensus on outcomes that should be considered in the COS for future studies on pregnancy-associated VTE.

Keywords: Delphi survey
Interviews
Outcomes
Patient-reported outcomes
Pregnancy
Venous Thromboembolism
Advisor: D'Souza, Rohan D
Exploring the Impact of Schooling on Identity Development of Diverse Students in Quebec

This research utilized Crenshaw’s intersectionality theory and Cummins’ (1996) coercive and collaborative relations of power framework to explore the experiences of five students who self-identify with multiple cultural identities and who have graduated from the public-school system in Quebec. The study is a qualitative research that employed narrative inquiry methodology to obtain participants’ narratives and experiences. The following areas of schooling in Quebec have significant impact on the identity development of diverse students. These revolved mainly around development of curricula and the implementations of educational policies. Firstly, religious expression and home culture; secondly, school environments; thirdly, sense of belonging and power dynamics; and fourthly, influence of parents. The findings reveal that participants who self-identified with various cultural identities appeared to have experienced conflicting situations in which school values and family values were not aligned. The school system appeared to have neglected supporting the development of students with multiple cultural identities.

Keywords: Diverse Students
Equity
Identity development
Intercultural Policies
Interculturalism
Intersectionality
Advisor: Lopez, Ann E.