VictorJuiz/thesis huggingface dataset:
Electroconvulsive Therapy for Hospitalized Patients with Depression

Electroconvulsive therapy (ECT), the most effective treatment for depression in psychiatry, is underused due to stigma and lack of information regarding its risks and benefits. The aims of this thesis were to inform evidence-based use of ECT by identifying patient-level factors that influence the use of ECT and determining the association between ECT and rare but clinically important medical and psychiatric outcomes. The thesis included three projects using administrative health data of hospitalized patients with depression in Ontario, Canada between 2007 and 2017. The first project was a comprehensive assessment of patient characteristics associated with receipt of inpatient ECT in Ontario. Both clinically appropriate, and potentially inappropriate factors were associated with receipt of inpatient ECT, suggesting opportunities to increase appropriate utilization. In the second project, the risk of serious medical events associated with ECT compared to no ECT was evaluated using propensity score matching that adjusted for a large set of sociodemographic and clinical variables. There was no clinically significant increased risk of serious medical events – as measured by medical hospitalization or death – with ECT exposure. In the third project, weighting by the odds of the propensity score was used to compare the risk of suicide among individuals receiving ECT vs. similar individuals not receiving ECT in the year following discharge from psychiatric hospitalization. ECT was associated with a significantly reduced risk of suicide and all-cause death. Taken together, these findings provide important data that can be used to support the evidence-based use of ECT in a highly vulnerable clinical population.

Keywords: Clinical Epidemiology
Depression
Electroconvulsive therapy
Psychiatry
Suicide
Advisor: Vigod, Simone N
Beyond the Numbers: An Intersectional Exploration of the Undergraduate Engineering Student Experience

The engineering profession seeks to diversify the people studying and practicing engineering. In Canada, diversity initiatives have focused on achieving gender parity for women, but progress has been slow. Little research exists that considers cultural systemic barriers, or the experiences of engineering students which could help explain why more progress to increase diversity in the engineering profession has not been made. This study explores inclusivity through the experiences of undergraduate students studying engineering at Ontario universities. Utilizing intersectionality as my framework and approach, I considered the complexities of students’ experiences through the dimensions of oppression and multiple identities. This mixed-methods study collected quantitative and qualitative responses from fifty-two undergraduate engineering students through an online survey and semi-structured one-on-one interviews with ten of the participants to answer the following research questions: how do students from marginalized groups describe their experiences in engineering education and how do those experiences vary for students of different genders, races, sexual orientations, disabilities, and socio-economic statuses? This study explored how identity impacted students’ experiences, whether students felt advantaged or disadvantaged by those experiences, and what students think their universities could do to provide a more inclusive learning environment. The key finding of this study was that students’ identities did impact their experiences in engineering education. Participants shared stories of marginalization and limited access to the whole engineering experience, meaning some students were underserved by their engineering programs and not fully engaged by the opportunities available to them. Women, queer students, racialized students, and students from lower socio-economic status described being excluded from the engineering student culture and community. Students from lower socio-economic backgrounds, students with disabilities, Black students, and women described experiences of othering, microaggressions, and discrimination. The stories and experiences shared by participants provides some evidence of a culture in engineering education that upholds maleness, whiteness, ableism, and classism. This finding implies that to be effective diversity initiatives need to address the culture and systemic socio-cultural constructs of power found in engineering education. Based on my findings and implications I provide recommendations for future research and outline strategies that engineering educators might utilize to make engineering more inclusive.

Keywords: engineering education
equity
diversity and inclusion
intersectionality
student experience
Advisor: Hildyard, Angela
Use of Compound-specific Isotope Analysis to Investigate Enzymatic Reaction Mechanisms

To maximize the efficiency of biodegradation in groundwater at contaminated sites, it is imperative to understand biodegradation reaction mechanisms. Compound-specific isotope analysis (CSIA) is a powerful approach that provides novel insights into biodegradation reaction mechanisms, enzyme kinetics and bioremediation potential and efficiency. This thesis aims to extend the discipline of CSIA in several new directions including its use as a means for probing reaction mechanisms, and for examining enzyme kinetics and biodegradation efficiency for halogenated alkanes. This thesis expands the application of CSIA to a new class of compounds, chlorofluorocarbons (CFCs). Significant carbon isotope fractionation was observed during biotransformation of CFC- 113 and CFC-11, and experimental findings applied to investigation of a contaminated field site. Carbon isotope fractionation of CFC-11 in groundwater suggested up to 86% transformation was occurring. Science and public attention remain focused on CFCs, due to recently reported unexplained source inputs to the atmosphere, and the potential for CFC biotransformation in surface and groundwaters remains unclear. Further biotransformation experiments integrated chlorine isotope with carbon isotope analysis for 1,1,1-trichloroethane (1,1,1- TCA) and 1,1-dichloroethane (1,1-DCA). Carbon isotope effects for 1,1,1-TCA and 1,1-DCA biotransformation are suppressed while ΛCl/C are consistent, suggesting a non-fractionating masking effect is present in 1,1,1-TCA and 1,1-DCA biotransformation. In contrast CF biotransformation by the enriched culture SC05 produced highly suppressed carbon and chlorine isotope effects, resulting in significantly different ΛCl/C values. These results are inconsistent with a non-fractionating masking effect and indicate differences in reaction mechanisms or an isotopically fractionating masking effect. The observational data and insights into underlying controls on isotopic fractionation observed for the experiments and field applications herein emphasize the need to understand mechanistic and kinetic controls on carbon and chlorine isotope effects. Studying RDases using CSIA has implications for understanding the role of reductive dehalogenation in the global halogen cycle that influences environmental contamination, atmospheric chemistry and, in turn, climate.

Keywords: chlorinated alkanes
compound-specific isotope analysis
reductive dechlorination
reductive dehalogenases
Advisor: Sherwood Lollar, Barbara
Zombie: A Soluble Signal Emitted by Dying Cells that Drives Neoplastic Transformation

Cancer often exhibits elevated levels of death linked to oncogenic stress, hypoxia-induced necrosis, and therapy-related killing. Some types of inflammatory molecules facilitate cancer repopulation after cell death. However, it is unclear whether dying cells can promote cancer independent of inflammatory networks. I exploited the classic, soft agar colony formation assay, an in vitro measure of anchorage-independent growth (AIG), a hallmark of neoplastic transformation. Several types of dying cells promoted the transformation of non-transformed, immortalized epithelial cells, independent of immune cells. I named this post-death pro-cancer activity “Zombie” and performed column fractionations, revealing that Zombie is a hydrophilic, 50-150kDa protein(s). Mass Spectrometry analysis of the semi-purified fractions identified ~160 Zombie candidates. Finally, I employed CRISPR knockout and chemical intervention to examine top candidates. Single null up to septuple null cells were created, and deletion of previously reported death-induced inflammatory factors did not affect Zombie activity, underscoring the novelty of Zombie-induced AIG.

Advisor: Bremner, Rod RB
Old Acquaintances and New Sisterhoods: Female Friendship in Classical Hollywood Cinema

This dissertation examines representations of female friendship in Hollywood films from 1930-1953. I seek to demonstrate that the first half of the twentieth century was a crucial period of transition in thinking about female friendship and how women relate to each other. The period I consider is largely marked by an increasing distrust of close friendships between women and a subsequent pivot towards a redefinition of and reinvestment in heterosexual courtship and marriage. At the same time, widespread socio-cultural changes were bringing about circumstances through which women were spending increasing amounts of time with their peers. Women were meeting, learning about, and forming bonds with increasing numbers of women, including those with lives and experiences radically different from their own. Hollywood movies played a role in creating this connectivity between women, both as a public, social space and, most pertinently for this dissertation, as a platform for female viewers to connect with and relate to other women. Many of the films I examine pick up and reinforce ideas about female friendship already circulating in popular discourse, albeit with a distinctly Hollywood spin. Broadly speaking, I identify the early twentieth-century as marking a shift in female friendship styles away from the intense, dyadic friendships of the Victorian period towards social, collective friendship groups. This does not mean, however, that Victorian style friendships disappear entirely. Indeed, the period I examine is marked by continuous negotiations and contradictions, allowing multiple friendship styles to exist simultaneously. I argue that many of the traits prized in Victorian friendships, most notably emotional intimacy, reciprocity, equality, and supportiveness, continued to define the new friendship styles that would emerge in the twentieth century. At the same time, these Victorian traits were re-imagined in a new context. Group friendships are emblematic of the increasingly public lives of twentieth-century women as well as both the new opportunities and new challenges that came with these lives. Women’s friendships took on a newly pragmatic function as practical support became increasingly important. The films I examine take up many of these key elements of female friendship, translating them into visual and narrative terms.

Advisor: Columpar, Corinn
Droplet Impact, Infiltration, and Boiling in Pores and Porous Media

In the baking industry, metallic, porous media beds are cyclically heated and then sprayed with water to generate the steam that is crucial for many baked products. Unfortunately, any improvements to these steam generators are slowly made by trial and error because fundamental studies into this mode of steam generation are absent from the literature. Experiments are performed on how individual drops impact and infiltrate long, narrow gaps and porous media to understand the trade-off between impact velocity and pore size on the drop’s infiltration time. Long, narrow gaps are heated to 130°C and 230°C to observe how the gap temperature influences the infiltration and evaporation of a water drop. An evaporation balance is designed to quantify the amount of steam that is generated from a porous media bed and different media bed configurations are tested. The infiltration of water inside narrow gaps and porous media slices can be predicted by a radial capillary model, which is an improvement over the commonly used Washburn capillary rise model. Photographs of the drop simultaneously spreading and infiltrating clearly show that drops commence infiltration into gaps and porous media immediately upon impact for We>7. Cleaving of the drops, when only a portion of the drop infiltrates, occurs when pore sizes are large and/or impact velocities are high. Criteria that predict the cleaving of drops on narrow gaps and porous media are established. For heated gaps, larger gap sizes permitted more of the drop to infiltrate and remain in the gap. For the 100 µm gap size the steam generated inside the gap repeatedly stopped the infiltration. Using the evaporation balance, media beds made from larger media evaporate more water than media beds made from smaller media. The porosity of the media bed did not produce a measurable difference in quantity of steam generated. It is shown that steam generation increases with a decreasing Fourier number and that steam generators should be designed with a Fo

Keywords: baking
capillary flow
evaporation
inerita
steam
Advisor: Chandra, Sanjeev
Solid-state Extraction of Nickel from Nickel Sulphide Concentrates by Iron Addition

Nickel is a strategic metal in modern society and is widely used in stainless steel, Ni-based alloys, electroplating, and batteries. Nickel production from sulphide nickel ores constitutes approximately 30% of all nickel produced worldwide. The conventional extraction process begins with the smelting of nickel sulphide concentrates, producing large quantities of SO2, either released to the atmosphere directly or captured at a cost. The high cost of SO2 abatement alone has, in instances, resulted in the shutdown of nickel smelters. The smelting product, nickel sulphide melt (known as Bessemer matte), is not directly marketable and has to be further refined by a long series of steps. The refining process is complex, costly, and energy-intensive. This research focused on developing a novel Ni extraction method from sulphide concentrates with minimal SO2 emissions. Under a neutral atmosphere, heating mixtures of metallic iron powders and nickel sulphide concentrates at 950 oC followed by slow cooling to 700 – 800 oC produced large ferronickel grains (d80 = 125 μm) and Ni extraction of approximately 98%. Grinding the particle size of the heat treatment products to below 44 µm yielded a significant liberation degree of the ferronickel grains. Through magnetic separation, the Ni-depleted iron sulphide was removed, producing a ferronickel (FeNi) concentrate with a grade of 15.6 wt% Ni. Additionally, the remaining S in the recovered FeNi concentrates was analyzed to be 3 wt%, demanding additional refining of FeNi if it was to be used for stainless steel production. The by-product, Ni-depleted iron sulphide, is a possible feed material for the production of iron oxide and sulfuric acid or elemental sulfur.

Keywords: ferronickel
iron sulphide
low temperature
nickel sulfide concentrate
solid-state nickel extraction
sulfur dioxide emissions
Advisor: Barati, Mansoor
Marcuson, Samuel
The Grounds of Transcendental Idealism

This dissertation consists of three papers on the role of ground in the metaphysics of transcendental idealism. In the first two papers, I provide novel reconstructions of Kant’s two main arguments for transcendental idealism. I show that both arguments rely on assumptions about the metaphysics and epistemology of ground that were commonplace in Kant’s time. In the third paper, I provide a new interpretation of transcendental idealism, by drawing a conceptual distinction between two forms of intentionality: reference and truthmaking. I argue that this interpretation manages to avoid many of the traditional problems for traditional readings of Kant.

Keywords: Ground
Kant
Metaphysics
Transcendental Idealism
Truthmaking
Advisor: Stang, Nicholas F
Quality of Early Childhood Education and Care: Examining Different Conceptualizations and Levels of Quality

A large proportion of young children spend many hours in early childhood education and care (ECEC) and such care is costly. Given this context, it is important to examine the quality of care children receive, whether they experience quality differently, and the effects of quality on child development. Exposure to high quality ECEC is expected to promote child development. However, results linking ECEC quality to children’s outcomes are mixed. Perhaps researchers need to focus on different aspects of ECEC quality. Alternatively, limitations of the literature may explain this inconsistency, as assessments of ECEC quality often aggregate across individual children to the classroom level, and such research is conducted primarily in the U.S. My two dissertation papers address gaps regarding what impacts quality, children’s differential experiences of quality, and associations between quality and child outcomes. Both papers focus on classrooms serving preschool-aged children. The first paper is a systematic review and meta-analysis examining the role of educator early childhood specialization on a range of preschool-aged children’s outcomes. Findings from this paper indicate that this quality indicator is not strongly or consistently associated with the outcomes examined in the literature. Limitations of the literature are discussed as possible explanations for the few results. The second paper uses archival data to assess ECEC quality at the child, classroom, and centre levels, by examining whether and why children are differentially treated by ECEC educators. This paper consists of two studies. The first examines educator differential treatment (DT) of children using educator-reports of their perceived closeness and conflict with each child in their classroom. The second examines DT using child-educator observations of social interaction and instruction. Results indicate that individual children have very different experiences in ECEC settings across a range of affective, social, and instructional domains, regardless of how DT is assessed. Educators reported closer and less conflicted relationships with prosocial children and directed more positive support and engagement towards children demonstrating oppositional behaviour. In addition to child behaviour, aspects of classroom quality showed associations with DT, however, results were inconsistent. Implications for public policy, resource allocation, and future research, particularly in Canada, are discussed.

Keywords: Child Care Quality
Differential Treatment
Early Childhood
Early Childhood Education and Care
Educator Training
Preschool
Advisor: Perlman, Michal
The Role of Myeloid Peroxisome Proliferator-activated Receptor Delta in Experimental Autoimmune Encephalomyelitis

Peroxisome proliferator-activated receptor δ (PPAR-δ) is a nuclear receptor that regulates whole body metabolic homeostasis, cell growth and differentiation. Previously our lab reported that mice lacking PPAR-δ (Ppardmut) developed more severe experimental autoimmune encephalomyelitis (EAE), with more proinflammatory T helper (Th) cells and macrophages. To elucidate the role of peripheral myeloid cells to this disease phenotype, EAE was induced in mice with a myeloid-specific PPAR-δ-deficiency (LysMCre:Ppardfl/fl). These mice developed more severe EAE compared to Ppardfl/fl controls, with an increased accumulation of pathogenic IL-17+CD4+ T cells in the CNS at the peak of EAE. Adoptive transfer studies and radiation bone marrow chimeras pointed to peripheral myeloid cells as the driver of this disease phenotype, substantiated by enhanced splenic myelin-specific Th1 and Th17 responses in LysMCre:Ppardfl/fl mice. Using a CD11b+:Th cell coculture system, CD11b+ cells from LysMCre:Ppardfl/fl mice were found to better at priming myelin-specific Th cells relative to Ppardfl/fl CD11b+ cells. The driver of this effect was predominantly increased expression of IL-12p40 and higher secretion of IL-12p40 homodimer and IL-23 by LysMCre:Ppardfl/fl CD11b+CD11c+ cells. These results thus identified a novel role for PPAR-δ in DCs in the regulation of Th cell priming during EAE. To evaluate the contribution of PPAR-δ in microglia in EAE, we used mice with a microglia-specific PPAR-δ-deficiency (Cx3cr1CreERT2:Ppardfl/fl), where tamoxifen (TAM)-treated mice exhibited microglial specific Ppard knockdown at 30 days. TAM-treated Cx3cr1CreERT2:Ppardfl/fl mice experienced worse EAE relative to TAM-treated Ppardfl/fl controls. Histopathology and magnetic resonance studies revealed increased Iba-1 immunoreactivity, axonal injury, and CNS atrophy in TAM-treated Cx3cr1CreERT2:Ppardfl/fl mice compared to controls. In early EAE, Cx3cr1CreERT2: Ppardfl/fl and Ppardfl/fl groups, Ppard-deficient microglia exhibited a more reactive phenotype as evidenced by a shorter maximum process length, lower expression of microglial genes associated with homeostasis, and higher expression of genes associated with reactive oxygen species generation, phagocytosis and lipid clearance, M2-activation, and inflammation. Our results therefore suggest that PPAR-δ is important in limiting the pro-inflammatory activities of microglia during EAE. Together, these studies expand upon the existing understanding of PPAR-δ in the immune system and are the first studies to evaluate the cell-specific roles of PPAR-δ in EAE.

Keywords: dendritic cells
experimental autoimmune encephalomyelitis
microglia
Advisor: Dunn, Shannon E
Understanding the Drivers of Low-value Care and De-implementation Processes: A Multi-methods Study

Low-value care (LVC) are tests, treatments, medications or procedures which have been deemed, through evidence, to be ineffective, harmful or unnecessary. It is estimated that 30% of current healthcare dollars are spent on these practices (Canadian Institute for Health Information, 2017). The de-implementation of low-value care is widely recognized as critical for patient safety, healthcare resources and health system sustainability. In recent years, a number of initiatives, such as Choosing Wisely, have targeted the de-implementation of low-value practices in healthcare. The de-implementation of LVC is an important endeavour that poses challenging conceptual and practical questions. This dissertation explores the conceptual and practical aspects of LVC and de-implementation through three complementary studies. In the first study, I conducted a comprehensive scoping review of the literature on the use of theory to understand or explain efforts to reduce LVC. This review offers four key findings: 1. De-implementation is still largely atheoretical, but the use of theory is increasing; 2. TDF is the most commonly used framework; 3. Theory was most commonly used to identify determinants or inform data analysis; and 4. The lack of studies examining the impact of patients on efforts to de-implement LVC. In the second study, I developed the Implementation Process Model (IPM) using a modified Delphi approach. This study, to advance understanding of de-implementation processes and explicate the elements of implementation processes, identified four critical elements important to implementation processes: 1. Stakeholder engagement throughout the process; 2. Iterative nature of implementation processes; 3. Importance of context; and 4. Importance of using guiding theories or frameworks. The third study used the knowledge and tools produced in the first two studies to conduct a qualitative exploration of factors which impact LVC and de-implementation processes. The findings of this study explicated the drivers of LVC, the magnitude of the problem of LVC and unique influences on de-implementation processes. Understanding LVC and de-implementation processes is critical to improving patient care, reducing waste and improving the healthcare system. The results of these studies provide insights into theoretical approaches, implementation processes, and factors which influence LVC and de-implementation applicable to both research and practice.

Keywords: Choosing Wisely
De-implementation
Low-value care
Qualitative
Scoping review
Theory
Advisor: Berta, Whitney