VictorJuiz/thesis huggingface dataset:
Towards Achieving a Home-based Brain Stimulation System

There is a major demand for alternative treatments for Major Depressive Disorder (MDD), as its main line of treatment, pharmacotherapy-based approaches, have limited effectiveness and low tolerability. A safe and effective home-based brain stimulation treatment would offer an accessible alternative to medications. Our objective was to develop a transcranial current stimulations (tCS) system that can provide an effective home-based treatment for MDD. To achieve that, we required: 1. an inexpensive solution for quick and accurate positioning of the stimulating electrodes, and 2. the ability to perform and adjust stimulation in real time. First, we developed and tested a quick and accurate positioning method using 3D scanning and 3D printing. Test results show accurate and precise positioning compared to other standard positioning methods. Second, we developed and tested an algorithm that can extract phase and frequency estimates from brain recordings and control the stimulation in real-time. Third, we developed a closed-looped brain stimulation system based on transcranial pulsed current stimulation (tPCS) that can effectively phase-lock to a particular brain oscillation frequency. We tested this novel brain stimulation approach to study its effect on the Salience Network, which is associated with MDD and other neuropsychiatric disorders. The results from our clinical trial did not show modulation of brain activity using the novel brain stimulation technique. Alternative stimulation protocols and tasks should be considered in order to better understand the potential of phase-locked tPCS. We achieved our objective of creating a solution to quickly and accurately position the stimulator, and a method to perform and adjust stimulation in real time. Furthermore, we were able to show that phase-locked tPCS does not show modulation of SN activity, as measured using established tasks and outcome measures. Future experimentation on phase-locked brain stimulation will help discover its potentials in helping MDD patients.

Keywords: Brain stimulation
closed-loop brain stimulation
Home-based brain stimulation
non-invasive brain stimulation
Personalized medicine
Transcranial brain stimulation
Advisor: Zariffa, José
Downar, Jonathan
Teacher Unions in the Public Sphere: Strategies Intended to Influence Public Opinion

This study explores how teacher unions in British Columbia and Ontario attempted to influence public opinion during periods of labour conflict between 2001 and 2016. A comparative case analysis was conducted based on eight interviews with members of the British Columbia Teachers Federation, six interviews with members of the Elementary Teachers’ Federation of Ontario, as well as documents from each union. In addition, newspaper items published in each province during the conflict period were collected. The unions’ efforts were analyzed through the framework of Habermas’ concepts of the public sphere and validity claims. Findings indicate that both unions had active public relations strategies designed to influence media coverage and discourse in the public sphere. However, most of their efforts were focused on influencing the public sphere indirectly, by using tactics that are not traditionally considered part of public relations strategies. While the unions’ efforts were similar in nature, the impact that these efforts had on influencing public opinion and producing policy change varied substantially. I argue that a combination of historical and political differences, mediated through a validity claims framework, helps explain this variation.

Keywords: education policy
public opinion
teacher unions
Advisor: Bascia, Nina
The Impact of Cannulation on the Development of Complications in Vascular Access for Hemodialysis: The Emerging Role of Real-time Imaging

Hemodialysis (HD) requires a reliable functional vascular access (VA) that can withstand frequent cannulation. The patency of an established VA is largely dependent on optimal cannulation practice, however, the systematic study of cannulation per se on the development of access complications is remarkably limited. Complications such as aneurysms or stenosis require interventions, adding significant burden of illness to this patient population along with the fiscal burden to the health care system. Access complications derived from cannulation are the focus of this work. Specifically, the mechanical trauma related to needle punctures and/or hemodynamic changes related to blood flow disturbances during dialysis. Using point of care ultrasound (POCUS), a large number of subclinical complications were detected in what were deemed clinically uneventful cannulations. Further, it was determined that less than 10% of needles were situated in the center of the vessel lumen. POCUS revealed distinct flow patterns of two cannulation devices, metal needles and plastic cannulae, during HD. Hemodynamic effects of cannulation devices per se in the development of cannulation complications were considered. Using principles of knowledge translation, a research framework was developed to standardize optimal cannulation practice to minimize the mechanical trauma of cannulation. With a structured intensive VA training program including simulation and cannulation of complex cases with POCUS, all cannulators achieved advanced ultrasound competency level with 99% accurate needle placement at approximately 500 cannulations. These learnings focused the research question on addressing the role of the cannulation device per se in the development of vascular access complications. The randomized control trial of metal needles vs. plastic cannula demonstrated that infiltrations during HD were higher for metal needles (RR = 2.2). Plastic cannula trended to lower procedural burden. The annual cost benefit was approximately $2,000 /pt. for the plastic cannula group. The three areas addressed in this thesis will inform the future evaluation of: • The impact of educational programs in VA outcomes (expert cannulation competency) • The impact of alternate clinical delivery model (POCUS, APS) incorporating research, education, training, and evaluation of cost pertaining to cannulation • The design of a pragmatic RCT of cannulation devices to optimize clinical and fiscal outcomes.

Keywords: Cannulation
Complications
Hemodialysis
Imaging
POCUS
Vascular Access
Advisor: Donnelly, Sandra M
Discovery of Novel Antibiotics via Streptomyces sporulation

Streptomyces are filamentous bacteria known for producing a wide range of bioactive molecules. In addition to being nature’s chemists they have a unique multicellular life-cycle that ends with the sporulation of aerial hyphae. I used this unique Streptomyces development cycle, specifically sporulation, as a screening platform to discover novel biologically active molecules and characterized their mechanisms of action. Min-1 inhibits the growth of a range of Gram-positive bacteria, is active against the cell envelope, and induces a short cell phenotype in Bacillus subtilis. Another molecule, EN-7, inhibits bacterial gyrase and is active against extensively resistant Staphylococcus aureus in addition to other Gram-positive pathogens. In addition to investigating these specific molecules, I developed a high-throughput screen to identify molecules that disrupt the Gram-positive bacterial membrane and found that Streptomyces venezuelae sporulation is highly sensitive to multiple forms of DNA damage.

Keywords: Antibiotics
Bacterial morphology
Chemical biology
Screening
Streptomyces
Advisor: Nodwell, Justin R
The Synthesis and Reactivity of Main Group Heterocycles via Frustrated Lewis Pair Chemistry

Combinations of sterically encumbered Lewis acids and bases, now referred to as a frustrated Lewis pair (FLP), have been shown to have a rich and diverse chemistry. Their advent led to the development of hydrogenation catalysis and other important transformations based on metal-free systems. This thesis investigates the chemistry of main group heterocycles, specifically those bearing phosphorus and/or boron atoms, within the realm of frustrated Lewis pair chemistry. Investigations of nitrogen Lewis bases included bulky anilines substituted with para-methoxy groups, which were found to undergo a tandem aromatic hydrogenation/transannulation reaction to yield bicyclic ammonium hydridoborate salts. Alkenyl- and alkynyl-tethered N-heterocycles were found to undergo intramolecular ring closure across the C–C -bond when treated with B(C6F5)3. Frustrated Lewis pairs were found to undergo 1,3-addition to N-sulfinylamines, which generated phosphinimine-borane and phosphinimine-alane adducts of sulfur monoxide. The activated species were found to oxidize triphenylphosphine and transfer sulfur monoxide to Wilkinson’s complex and N-heterocyclic carbenes. Triphosphabenzene was shown to activate H2 independently, and the mechanism of this reaction was investigated. Phosphaalkynes did not react with prototypical phosphine-borane FLPs, however they were amenable to hydroboration with Piers’ borane, which resulted in an unexpected regiochemical outcome. The reactivity of the dimeric P2B2 heterocycles was examined. Aliphatic ketones were demonstrated to undergo stoichiometric reduction to the corresponding borinic esters when exposed to one equivalent of B(C6F5)3 and H2. This methodology was applied to polycyclic aromatic diones, which resulted in formation of neutral borocyclic radicals. The chemical properties of the radicals were examined, and their reactivity with phosphorus, carbon, and nitrogen nucleophiles was explored.

Advisor: Stephan, Douglas W
Designing Names: Requisite Identity Labour for Migrants' Be(long)ing in Ontario

This dissertation responds to the question of why people who immigrate to Ontario, Canada frequently choose to use their personal names in altered forms. Between May and December 2010, I engaged in semi-structured interviews with twenty-three people who, while living in Ontario, experienced name challenges ranging from persistent, repetitive misspellings and mispronunciations of their original names to cases of significant name alterations on residency documents, and even to situations of exclusion and discrimination. Drawing on critical perspectives from literature on identity and performativity, science and technology studies, race and immigration, affect, and onomastics (the study of names), I establish that name challenges are a form of "identity labour" required of many people who immigrate to Ontario. I also describe how individuals' identity labour changes over time. In response to name challenges, and the need to balance between their sometimes-simultaneous audiences, participants design their names for life in Ontario--by deciding which audiences to privilege, they choose where they want to belong, and how their names should be.

Keywords: belonging
identity
identity labour
immigration
names
power
Advisor: Caidi, Nadia
Graphical Management of Attentional State

Adaptive user interfaces (AUIs) modify their information content, structure, or interactions in response to changes in operating context, called triggers. This dissertation focuses on the operator measurement class of triggers, which initiate interface adaptations based on changes to an operator’s physical or mental state. To infer a user’s mental state, we used Passive Data Monitoring (PDM), which is a method that examines streams of interaction data for patterns that are characteristic of an attentional state. AUIs can then search for these patterns and adapt an interface accordingly. This dissertation presents three studies that advance the methodology by which attentional states are detected via PDM and responded to via AUIs. The first study describes two experiments, which identified the behavioural correlates of attentional switches and implemented interventions that mitigated the performance decrement incurred from those switches, respectively. Experiment 1.1 revealed that there was a significant interruption in participant interaction both before and after attentional switches. Experiment 1.2 showed that both of these delays could be reduced by implementing an intervention that contextualized a switch. The second study describes one experiment aimed at developing a machine learning classifier that could detect when participants were in an attentional tunnel. A Convolutional Long Short-Term Memory neural network accurately identified states of attentional tunneling significantly above chance level. This experiment also explored the performance tradeoffs stemming from attentional tunnels. The third study describes two experiments aimed at developing machine learning classifiers capable of detecting information overload and using those classifiers as the engine for an AUI that performed online calibration of the degree of concurrent information presentation, respectively. In the first experiment, four classifiers were developed that all performed above chance level. In the second experiment, two of these classifiers drove two separate AUIs that significantly benefited some user groups relative to experimental controls. The experiment revealed significant differences in how user groups responded to AUIs. Overall, this dissertation contributes to our understanding of how attentional states manifest behaviourally. It also formalizes PDM as a method for understanding, detecting, and leveraging these behavioural manifestations for use in AUIs.

Keywords: Adaptive User Interfaces
Attentional Design
Human Factors
Machine Learning
Passive Data Monitoring
Advisor: Jamieson, Greg A.
Characterizing the Role of SUMO in Transcriptional Repression in S. cerevisiae

Small ubiquitin-like modifier, SUMO, is a member of the ubiquitin-like protein family. Similar to ubiquitin, SUMO is conjugated to target proteins as a post-translational modification via an E1, E2, and E3 enzymatic cascade, in a process known as SUMOylation. SUMOylation leads to altered target protein localization, half-life, or protein-protein interactions. Bursts of SUMOylation following stresses (SUMO Stress Response / SSR) have been documented, however what triggers the SSR, the kinetics of the response, and the cellular components necessary to mediate the response have not been well characterized. Additionally, SUMO has been widely implicated in transcriptional regulation and chromatin organization, although the nature of its role remains unclear. This thesis aims to: 1) complete a comprehensive characterization of the SSR, and 2) elucidate the true role of SUMO in transcriptional regulation and chromatin organization. To this end, I characterized the SSR following a variety of stresses and time courses. I then used mutants and inhibitors to demonstrate that the SSR is triggered by coordinated transcriptional changes (such as in response to a stress). RNA-Seq of a SUMO system mutant identified 162 transcripts which show a SUMO-dependent transcriptional de-repression following SUMO system inactivation. These transcripts are primarily inducible genes which are normally induced under specific conditions. Notably, these mutants were still able to activate and inactivate transcription in response to a stress, demonstrating that SUMO is not required for acute transcriptional activation or inactivation. Subsequently I investigated possible mechanisms for SUMO-dependent transcriptional repression. Firstly, I used pulldowns and site directed mutagenesis to demonstrate that Rlf2, a component of the histone chaperone CAF-1, is able to bind SUMO in S. cerevisiae. This raises the possibility that CAF-1 plays a role in SUMO-mediated transcriptional repression. Secondly, I used ATAC-Seq to demonstrate that SUMO system inhibition may increase chromatin openness, which could lead to the observed transcriptional de-repression. Together, these data indicate that SUMO may be involved in maintaining chromatin in a closed state; however, further research is needed to elucidate the mechanism. These experiments assist in understanding the role of SUMOylation and the consequences of using SUMO as a therapeutic target.

Keywords: chromatin
RNA-seq
stress response
SUMO
transcription
Advisor: Raught, Brian
Understanding the Processing of Tonal Modulations During Musical Listening Using Behavioural and Neural Techniques

The series of experiments presented in this dissertation elucidates the perceptual and cognitive processing of tonal modulations during musical listening using behavioural measures and electroencephalography (EEG). The purpose of these experiments was to shed light on mechanisms of working memory pertaining to the management of competing activated schemata. The experiments utilized an adaptation of the harmonic priming paradigm typically used in the music cognition literature to study the facilitation of stimulus processing resulting from top-down expectancies generated by a musical stimulus’ tonal structure. Musicians and non-musicians were presented with extended primes containing two equally represented tonalities, and subsequent targets that were related exclusively to the first tonality presented in the prime, exclusively to the second tonality presented in the prime, or neither tonality. Participants provided subjective judgements of target fit (i.e., “fit” versus “does not fit” with the preceding prime), as well as ratings of the degree of fit using a scale from 1-7. The results of the reaction time analyses generally replicated previous studies of tonal modulations, demonstrating that the activation of an original tonality decays rapidly once a new tonality is introduced, as reaction times were equivalent for targets related to versus unrelated to the original key. However, the results of the ratings of fit showed that although an original tonality may not be activated and readily available in working memory at target onset, when given sufficient time, participants are able to retrieve relevant priming information to guide their responses. Additionally, the results of the EEG analyses corroborated the findings of the reaction time analyses, as event related potentials typically elicited by unrelated targets (such as the early right anterior negativity [ERAN], the N500 or late positive component [LPC]) were not elicited for contrasts between targets related to the original key and unrelated targets.

Keywords: ERAN
harmonic priming
LPC
music cognition
schematic expectancies
tonality
Advisor: Schmuckler, Mark A
Alain, Claude
Coronary Wall Imaging Using Coronary CT Angiography

CT coronary angiography has been suggested as a non-invasive method for visualization of the coronary artery wall and early detection of the plaque. The ability to noninvasively detect and analyze high-risk plaques at an early stage, could lead to early initiation of the targeted treatment to improve risk stratification without the need for more invasive procedures. There are limitations however, mainly related to spatial, contrast and temporal resolution of CT. Resolving these limitations was the main focus of the current thesis. The first study of this thesis focused on choosing the optimal tube current and voltage. A coronary plaque phantom was scanned on a wide volume CT. Spatial resolution, contrast resolution, and vessel wall thickness were measured at different x-ray tube currents and voltages. The study revealed that wall thickness was measured more accurately at intermediate currents with mid-range contrast resolution but optimal spatial resolution. The second and third study of this thesis focused on the effect of multi-segment reconstruction algorithm on image blur. The second study included a Catphan with a moving platform attached, to simulate a patient’s heart rhythm in real time. The phantom was scanned on a third-generation wide volume CT using single and multi-segment reconstruction algorithm. The results proved that Two-segment reconstruction significantly reduced the image blur. The third study was a pilot clinical study to validate findings of the phantom study. The study included patients required to have CT coronary angiography. The average blur across five images for each patient was calculated in single and multi-segment reconstructed images. The study validated the results of the phantom study proving that multi-segment reconstruction significantly reduced image blur compared to half scan reconstruction. Together we concluded that using the right protocol and multi-segment reconstruction algorithm, CT coronary angiography could be utilized for visualization of the coronary artery wall.

Keywords: coronary artery
Coronary motion
vulnerable plaque
Advisor: Paul, Narinder
Wright, Graham
Women in Canadian Independent School Leadership: Perceptions, Career Patterns, and Possibilities

Guided by the research question, How do women faculty in independent schools enter and advance to school leadership positions, this exploratory qualitative study sought to understand perceptions of women in independent school leadership in Canada. Giddens’ (1976) structuration theory, focusing on the interplay between organization and individual, informs the conceptual framework and illustrates inherent tensions between structure and agency in this context. Data collection included fifteen participants’ responses to semi-structured interviews and a survey of independent schools. This highlighted the strategies, barriers, and organizational facilitators that shape the trajectory of women’s leadership climb as it moves through critical stages in a climate of post second-generation gender bias. Moreover, this research examines how such forces impact women’s societal, organizational, familial, and individual identities. Findings reveal that women’s leadership in coeducational independent schools remains underrepresented at the highest levels. Women enter leadership later and become concentrated in the middle stages of the climb. This, despite the finding that women’s educational credentials often surpass those of their male counterparts. Women tend to lack the valuable executive and financial experience that hiring boards prioritize. Moreover, the historic culture of many schools has established a paradigm of leadership that has not been an easy fit for women leaders. Compounding these barriers, women’s careers seemed to coincide with child rearing years and domestic duties, leading to the “double shift”, and a reluctance to move for promotion. Strategies for leadership success include early entry into leadership, performance, mentorship and sponsorship, and a belief that self-improvement leads to school improvement. This study addresses implications for practice, policy, and research, with a clarion call for prioritization of equity in executive leadership, the comprehensive development of programming and supports to encourage early interest and greater numbers of women in independent school leadership. Finally, the study shows a need to reshape the paradigm of leadership to become more inclusive, while also challenging societal perceptions of women as leaders. keywords: women’s leadership, independent schools, career patterns, leadership climb, head of school, Canada, CAIS, identity.

Keywords: career patterns
independent schools
leadership identity
organizational behavior
women’s leadership
Advisor: Ryan, James