VictorJuiz/thesis huggingface dataset:
The Impact of Cannulation on the Development of Complications in Vascular Access for Hemodialysis: The Emerging Role of Real-time Imaging
Keywords: Cannulation
Complications
Hemodialysis
Imaging
POCUS
Vascular Access

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.
Discovery of Novel Antibiotics via Streptomyces sporulation
Keywords: Antibiotics
Bacterial morphology
Chemical biology
Screening
Streptomyces

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.
Designing Names: Requisite Identity Labour for Migrants' Be(long)ing in Ontario
Keywords: belonging
identity
identity labour
immigration
names
power

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.
Graphical Management of Attentional State
Keywords: Adaptive User Interfaces
Attentional Design
Human Factors
Machine Learning
Passive Data Monitoring

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.
Characterizing the Role of SUMO in Transcriptional Repression in S. cerevisiae
Keywords: chromatin
RNA-seq
stress response
SUMO
transcription

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.
Understanding the Processing of Tonal Modulations During Musical Listening Using Behavioural and Neural Techniques
Keywords: ERAN
harmonic priming
LPC
music cognition
schematic expectancies
tonality

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.
Coronary Wall Imaging Using Coronary CT Angiography
Keywords: coronary artery
Coronary motion
vulnerable plaque

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.
Women in Canadian Independent School Leadership: Perceptions, Career Patterns, and Possibilities
Keywords: career patterns
independent schools
leadership identity
organizational behavior
women’s leadership

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.
Acute Inflammatory Response as a Mediator of the Effects of High-intensity Exercise on Appetite and Food Intake in Boys.
Keywords: Appetite control
Children
Exercise
Food Intake
IL-6
Inflammation

The effect of high-intensity exercise (HIEX) and the mechanism by which it suppresses appetite and food intake (FI) is not well understood. The hypothesis of this research was that inflammation during and after HIEX plays a role. Three experiments were designed to investigate the hypothesis and to compare these mechanisms with the effects of macronutrient ingestion in male children. Experiment 1 investigated the effects of HIEX induced inflammatory- and stress biomarkers on appetite control in normal-weight (NW) and overweight/obese boys. HIEX resulted in reduced appetite that correlated with an increase in plasma concentration of IL-6 with no effect of body-weight. However, while a role for IL-6 in the response can be suggested, the suppression of appetite could have been mediated by the associated decrease in active ghrelin and/or increase in cortisol. Experiment 2 further examined the role of IL-6 in exercise-induced anorexia in NW children. HIEX reduced subjective appetite but not FI, increased IL-6 and cortisol and decreased active ghrelin and blood glucose. An independent role for IL-6 in appetite suppression was not supported. However, IL-6 response was associated with active ghrelin and cortisol, thus potentially mediating appetite via these interactions. Experiment 3 was a study of the role of IL-6 and TNF-α in satiety and appetite after consumption of glucose or protein beverage by boys. Neither affected an immediate response in plasma IL-6 and TNF-α concentrations. However, in the pooled data, mean levels of IL-6 were strongly correlated with later FI. Thus, this research provides support for further examination of the role of IL-6 in appetite control.
Exploring the Synthesis and Reactivity of Phosphinoboranes and Organophosphorus-based Lewis Acids
Keywords: Catalysis
Frustrated Lewis pairs
Lewis acid
Phosphinoborane
Phosphonium
Phosphorus

Advances in main group chemistry are challenging the status of the transition metals. Small-molecule activations necessary in many catalytic reactions have traditionally been the province of the transition metals owing to their large atomic radii, available d-orbital electrons, vacant coordination sites, and accessible orbital energies. Increasingly however, main group species are being discovered with accessible donor and acceptor sites capable of activating small molecules in analogous and complementary reactions to the transition metals. The first portion of this thesis explores the synthesis of phosphinoboranes and their reactivity towards a number of small molecules: acyl phosphine and chloroborane synthesis was achieved from reactions with benzoyl chloride, reactions with carbon dioxide produced single addition and diphospha-urea products, and addition reactions were observed with diazomethanes and diazobenzene. In the latter case, subsequent intramolecular frustrated Lewis pair chemistry of addition products with Lewis basic substrates yielded unique heterocyclic rings. Main group chemistry has also made progress in Lewis acid catalysis, where transition metals have traditionally been applied. Synthetic strategies for attaching highly electron-withdrawing substituents to main group element centres and the design of weakly coordinating anions have led to the development of main group Lewis super acids. The second part of this thesis explores the design and reactivity of phosphonium Lewis acids: fluorine-substituted phenoxy rings were applied to achieve more robust yet reactive compounds, a phenoxyphosphonium salt derivative was subsequently used to catalyze the double hydroarylation of diarylamines with alkynes, and steric considerations of the C6F5 group were compared to the 3,5-(CF3)2C6H3 group. Additionally, the development of main group Lewis acids containing ligands originally designed for transition metals have demonstrated stability, selectivity, and reactivity. The third part of this thesis explores the synthesis and hemilabile reactivity of diiminopyridine, bipyridine, and terpyridine ligated phosphorus-based Lewis acids towards the catalytic allylation of aliphatic carbon-fluorine bonds.
Enframing Infrastructural Place: Manhattan's Waterfront, 1686-1921
Keywords: enframing
governance
infrastructure
New York City
urban geography
urban planning

In 1870, Manhattan’s waterfront was a mixed-use site of abattoirs, storage-yards and factories. These buildings lined the rotting wooden boards of dilapidated too-small piers built on privately-owned land. This close-in, messy waterfront was unambiguously part of the rest of the city in terms of law, operation, and governance. Over the next 50 years, the waterfront would be trans-formed. By 1921, the waterfront was dominated by publicly-owned and built concrete and steel piers on parcels that were legally distinct from the rest of the propertied urban landscape. The world’s largest steamships tied up at exclusive berths governed by an institution that sought to ensure their frictionless circulation in and out of the city. By 1921, Manhattan’s waterfront was the exclusive site of large-scale transportation circulation – an infrastructural place. In this re-search I ask how the mixed-use urban waterfront became infrastructural place: the exclusive site of transatlantic circulation. I examine how state and private sector actors negotiated, contested, and cooperated to enframe the waterfront as infrastructure – a space ruled according to the logic of circulation– that enabled global-scale flows through Manhattan. This involved on a process of enframing which relied on the separate legal categories of property leveraged to produce new conceptual, institutional, and material boundaries separating the waterfront from the rest of the city. These processes were articulated through power geometries to produce the waterfront as infrastructural place. This research demonstrates how an analysis of infrastructure as place allows us to examine it as an ongoing process of social production.