VictorJuiz/thesis huggingface dataset:
Integrated Distortion Suppression Circuit for a High Fidelity Digital Class-D Audio Amplifier
Keywords: electronics
class D

Due to the lack of feedback networks, digital class D amplifiers operating in open loop typically have inferior performance when compared to analog class D amplifiers in closed loop configuration. This thesis presents an integrated distortion suppression circuit design for digital class D amplifiers, which forms a feedback loop around the output stage. This circuit suppresses the output stage distortion and noise by equalizing the modulator effective duty ratio and the output stage effective duty ratio. The suppression circuit is integrated with the class D modulator. An integrated class D amplifier output stage is implemented separately using a 0.35μm HV-CMOS technology. Experimental results confirm that the closed loop PSRR is improved by 15dB. The THD+N value is reduced by a factor of 2 to 30. The minimum THD+N is 0.03%, which is among the state of the art class D amplifiers.
A Wavelet-based Approach to Electrocardiogram (ECG) and Phonocardiogram (PCG) Subject Recognition
Keywords: Biometrics
ECG
PCG

This thesis studies the applicability of two cardiac traits, the electrocardiogram (ECG) and the phonocardiogram (PCG), as biometrics. There is strong evidence that cardiac electrical activity (ECG) embeds highly distinctive characteristics, suitable for applications such as the recognition of human subjects. On the other hand, having the same origin with the ECG signal, it is believed that the PCG signal conveys distinctive information of an individual which can be deployed in biometric applications. Such recognition systems traditionally provide two modes of functionality, identification and authentication; frameworks for subject recognition are herein proposed and analyzed in both scenarios. Moreover, the expression of the cardiac signals is subject to alternation with heart rate and noise components. Thus, the central consideration of this thesis is the design and evaluation of robust recognition approaches that can compensate for these effects. A recognition system based on each, the ECG and the PCG, is developed and evaluated. Furthermore, a fusion of the two signals in a multimodal biometric system is investigated.
Regulation of the 3BP2 Adaptor Protein by the Nedd4 Family of HECT E3 Ubiquitin Ligases
Keywords: 3BP2
Ubiquitin
Nedd4
HECT

3BP2 has been previously described as the protein mutated in the osteoporotic disorder, Cherubism. The gain of function mutation that characterizes Cherubism is the result of an uncoupling of its interaction with Tankyrase 2, which has been reported to stimulate 3BP2 ubiquitination. Here we describe an attempt at identifying the E3 ligase responsible for mediating this ubiquitination using four candidate members from the Nedd4 family. Based on their respective abilities to bind and ubiquitinate 3BP2, as well as their sensitivity to the presence of Tankyrase 2 and to 3BP2 mutations (including Cherubism mutations and mutations within the 3BP2 PPxY motif thought to confer binding to the Nedd4 proteins), we have determined that Smurf1 best fits our model. Further supporting these findings, we have seen an elevation in 3BP2 protein levels in macrophages derived from Smurf1-/-/Smurf2+/- mice. This work supports a role for the Nedd4 family member, Smurf1, in mediating 3BP2 ubiquitination.
Structural and Functional Characterization of IclR Transcription Regulators
Keywords: Transcription regulators
X-ray crystallography

This work is a part of a large project in our laboratory that is aimed toward characterization of prokaryotic transcription regulators from different families and their interactions with small-molecule effectors. My study was focused of IclR family of transcriprion regulators, specifically on its founding member Isocytrate Lyase Regulator (IclR) from E.coli and AllR regulator from E.coli, which share 42% sequence identity with IclR. I used a combination of biophysical, biochemical and structural biology techniques to explore the mechanisms by which IclR and AllR interact with their effectors. I performed site-directed mutagenesis experiments in order to research the role of individual amino acids in interaction of AllR regulator with its previously identified effector glyoxylate and to test whether oligomerization plays a role in effector-induced signal transduction by AllR. Using differential light scattering, which allows high-throughput screening of small molecules for thermostabilization of proteins, I identified potential effctors for the IclR regulator. The physiological relevance of these candidate molecules was tested in-vitro and in-vivo and their interaction with IclR was characterized by Isothermal Titration Calorimetry and X-ray Crystallography.
A Tailored Knowledge Translation Strategy to Increase Compliance with Guideline Recommendations for Preoperative bowel Preparation
Keywords: guidelines
knowledge translation

Background: There is strong level I evidence that in most patients, mechanical bowel preparation (MBP) is not required. Despite this, physician behaviour has been slow to change in favour of omitting preoperative MBP. Methods: A knowledge translation strategy including: guideline development, consensus, education by opinion leaders, audit and feedback and reminder cards, was used in this study. Results: Overall, 81.1% of patients in the “before” arm and 88.4% in the “after” arm received MBP in compliance with the guideline (p=0.038). Normal diet use was compliant with the guideline in 45.6% of the patients in the “before” arm and 55.8% in the “after” arm (p=0.080). The use of enemas was compliant with the guideline in 88.5% of “before” patients and 94.2% of “after” patients (p<0.001). Conclusions: The results of this study reveal that a tailored, multi-faceted knowledge translation strategy can be used to change surgeon behavior in this clinical scenario.
Single Molecule Imaging of Membrane Proteins: A study of the CorA Transporter by Scanning Probe Microscopy
Keywords: membrane protein
AFM

Elucidating the structure-function relationships of membrane proteins is critical for the design of therapeutic agents to treat disease and for understanding numerous cellular processes such as signal transduction and molecular or ion transport. Recent advances in the application of correlated single molecule imaging techniques have provided new insights into protein-protein and protein-membrane interactions. To demonstrate the potential of these approaches, we have used in situ atomic force microscopy and single molecule fluorescence microscopy to characterize the interactions between membrane receptors and their soluble ligands, examine the monomer-dimer equilibrium in a family of adhesion receptors, and elucidate protein-mediated membrane restructuring of a supported lipid bilayer. Building on these studies, we examined the CorA ion transporter protein. We demonstrated single molecule resolution of reconstituted CorA molecules in supported lipid bilayers using a correlated AFM-TIRF microscopy platform. This approach provided new insights into a purported mechanism of CorA activation that involved ion binding.
Outcomes of Children Receiving In-hospital Resuscitation
Keywords: 0766
0564

Introduction: This thesis prospectively evaluated the cognitive and functional outcomes and health-related quality of life of children admitted urgently to a Pediatric Intensive Care Unit (PICU) at the Hospital for Sick Children. Methods: The primary outcome was the Vineland Adaptive Behavioural Scale (VABS-2) measured at 1-month and secondary outcomes were health-related quality of life, daily functioning, and caregiver perceptions. Results: 56 children and 66 caregivers were enrolled; 42 (75%) patients and 49 (74%) caregivers completed the 1-month assessment. Children in the PICU had a mean VABS-2 score of 85(+25). Daily functioning outcomes did not significantly change from baseline to 1-month. In comparison to baseline, children had significantly reduced health-related quality of life at 1-week but no significant change was found at 1-month. Discussion: Children surviving PICU have significant cognitive morbidity and reduced health-related quality of life that is exacerbated by more intense modes of resuscitation and increasing severity of illness.
Trip Reporting and GPS-based Prompted Recall: Survey Design and Preliminary Analysis of Results
Keywords: GPS
Travel Survey
Trip Reporting
Prompted Recall

This trip reporting and GPS-based prompted-recall travel survey was undertaken to provide a better understanding of (a) demographic and behavioural differences between students with a home telephone land line and students without one (b) effects of carrying a GPS device on trip reporting (c) differences in trips reported and confirmed through a prompted-recall survey, and (d) performance of the TRIPS platform. The survey was designed and conducted at the University of Toronto between November 2008 and April 2009. It targeted mostly university students and returned 90 valid interviews. Participants were required to carry a GPS device with them for the two days surveyed. They were then asked to report their trips first, and then to confirm their recorded trips through the web-based prompted-recall tool, TRIPS. Preliminary analysis was conducted based on the reported data, and improvements to the TRIPS platform have been suggested.
Engineering Infra-red Photon Absorbing Materials for Organic Solar Cells
Keywords: Phthalocyanines
Organic Solar Cells
Bisphthalocyanines
Infra-Red
Nanoparticles
Miniemulsion
Uranyl Superphthalocyanine

This thesis aims to investigate different infrared absorbing molecules and how their properties are affected by their incorporation into polymer nanoparticles. Metal-free phthalocyanine-H2Pc, uranyl super phthalocyanine-USPc, and europium bisphthalocyanine were studied-EuPc2; the latter two capable of IR absorption. Due to the discovery of USPc’s moisture sensitivity, only H2Pc and EuPc2 were derivatized to facilitate encapsulation in polystyrene nanoparticles through a miniemulsion polymerization. These novel phthalocyanines attained loadings of up to 41wt% and exhibit substantial broadening of absorption peaks. Furthermore, the EuPc2 loaded particles also reveal an unprecedented gain in extinction coefficient of the NIR and radical absorption peaks. The leaching behavior of the dye was also studied, as this had not been undertaken in the literature, and revealed the need for a method of polymerizing/chemically binding phthalocyanines into nanoparticles; with preliminary steps taken to realize this goal.
Predicting Severity of Violent Recidivism by Aggression Type: What do Risk Instruments, Cognitive and Personality Scales Contribute?
Keywords: violent recidivism
severity

This study provides an initial analysis of how effective commonly used risk assessment and psychological tests are in postdicting the severity of the index offense and the individual’s most severe offense in a forensic inpatient sample. The study involved a chart review of risk assessment measures, cognitive and personality tests, and criminological data for 65 patients at St. Joseph’s Hamilton Mountain Centre for Mental Health Care. The results found a significant correlation between the Wechsler Abbreviated Scale of Intelligence (Wechsler, 1997) and index offense severity. Moreover, an aggression typology (Nussbaum, Saint-Cyr, & Bell, 1997) showed promising signs in differentiating severity by offender type. The study also suggests that further research is necessary in this area, given the limited relationship found between risk instruments and severity of violence, though the risk assessment measures did show good concurrent validity.
Health Technology Assessment of Thiopurine Methyltransferase Testing for Guiding 6-Mercaptopurine Doses in Pediatric Patients with Acute Lymphoblastic Leukemia
Keywords: Pharmacogenetics
Thiopurine Methyltransferase

This study determined whether phenotype or genotype tests for thiopurine methyltransferase (TPMT) are cost effective interventions for guiding doses of 6-mercaptopurine in children with acute lymphoblastic leukemia (ALL) compared to standard weight-based dosing. A systematic review of the literature was conducted to assess the accuracy of the TPMT technologies, followed by a cost effectiveness analysis which compared genotype, phenotype and weight-based dosing strategies over a three month time horizon. Both TPMT phenotype and genotype technologies were considered accurate though there is no gold standard. Additionally, included studies were of low methodological quality. Neither of the interventions showed a benefit in survival and both were more costly compared to standard weight-based dosing. At this time there is insufficient evidence to recommend the use of phenotype or genotype testing prior to 6-mercaptopurine therapy to guide initial doses in pediatric ALL patients.
Securing Script-based Extensibility in Web Browsers
Keywords: web browser
browser extensions
privilege escalation
JavaScript
Firefox
vulnerability

Web browsers are increasingly designed to be extensible to keep up with the Web's rapid pace of change. This extensibility is typically implemented using script-based extensions. Script extensions have access to sensitive browser APIs and content from untrusted web pages. Unfortunately, this powerful combination creates the threat of privilege escalation attacks that grant web page scripts the full privileges of script extensions and control over the entire browser process. This thesis describes the pitfalls of script-based extensibility based on our study of the Firefox Web browser, and is the first to offer a classification of script-based privilege escalation vulnerabilities. We propose a taint-based system to track the spread of untrusted data in the browser and to detect the characteristic signatures of privilege escalation attacks. We show that this approach is effective by testing our system against exploits in the Firefox bug database and finding that it detects the vast majority of attacks with no false alarms.
Sulfonyl Chlorides as Versatile Reagents for Chelate-assisted C–H Bond Functionalizations
Keywords: C-H bond functionalization
sulfonyl chlorides
transition metal catalysis

Despite the great abundance of C–H bonds in readily available starting materials, their use in synthesis of functionalized molecules has been hampered by the high bond strengths, rendering them inert to common organic reagents. However, recent progress in the field has addressed this issue, enabling selective C–H bond functionalizations to be performed using catalytic transition metal mediated processes. Herein, the use of sulfonyl chlorides as versatile reagents for C–H bond functionalizations is reported. Using chelation assistance, the regioselective conversion of C–H bonds to either C–S, C–Cl or C–C bonds was achieved. The methodology development, substrate scope determination and mechanistic investigations will be discussed.
The Effects of Oxidative Stress on Calcineurin Activity and DJ-1 Subcellular Localization
Keywords: oxidative stress
DJ-1, calcineurin

Oxidative stress and mutations in DJ-1, a redox sensitive protein, are linked to Parkinson's Disease. The protective mechanism of DJ-1 is unclear. I hypothesized that: 1) DJ-1 mediates protection by translocating to mitochondria after oxidative stress and, 2) when DJ-1 is downregulated, apoptotic pathways regulated by calcineurin are also downregulated. In PC12 cells and rat cortical neurons, oxidative stress resulted in the upregulation of DJ-1 and increased DJ-1 in the nucleus, but did not increase mitochondrial translocation of DJ-1. In cortical neurons and wildtype mouse embryonic fibroblasts, H2O2 induced cleavage of CnA into an inactive fragment. DJ-1 knockout fibroblasts had less nuclear localization of the transcription factor NFATc4, a substrate of calcineurin involved in apoptosis. H2O2 increased CnA cleavage in DJ-1 knockout fibroblasts, but NFATc4 localization was unchanged. These results suggest that the downregulation of apoptotic pathways regulated by calcineurin may be a compensatory response to the downregulation of DJ-1.
Tactile Cues in the Control of Action: An Emphasis on Movement Initiation
Keywords: Goal-directed movement
Perception

The ability to detect a tactile stimulus during movement is markedly decreased (e.g., tactile gating), yet it is unknown whether the stimulus influences motor output. In the present study, participants moved a mechanical slider as quickly and as accurately as possible to a target. Participants received low-level electrical stimulation on the index finger of the reaching limb at various offsets relative to movement initiation. Participants reported whether they perceived the tactile cue. It was hypothesized that the detection of the stimulus would be reduced and the stimulus would influence motor output. First, a typical time course and magnitude of sensory gating was found, supporting previous observations (e.g., Chapman & Beauchamp, 2006). Second, no influence of the stimulation on motor output was observed. It was concluded that the detection of tactile cues during a goal-directed reaching task is attenuated and this stimulation does not influence motor output.
Doe v. Canada: Lesbian Women, Assisted Conception, and a Relational Approach to Rights
Keywords: Reproductive health
assisted conception
relational theory
autonomy
feminism
equality

This thesis examines Doe v. Canada, a case brought before the Ontario Court of Appeals with the purpose to declare that the definition of “assisted conception” set forth by the respective regulations discriminated against lesbian women. The regulatory framework of assisted conception is embedded with heteronormativity, heterosexism and an over medicalization of reproduction. The traditional liberal conception of rights, embedded in the Court’s decision did not allowed lesbian women to have access to assisted conception free from barriers that other women, seeking insemination with semen donated by their spouse or sexual partner, do not have to endure. However, If we shift our perspective of rights from a liberal view to a relational approach, we will be able consider such decisions from a perspective that takes into account not only the physical health implications of the use of this technology, but also all other social, psychological and contextual relevant factors.
Opting in to an Opt-out System: Presumed Consent as a Valid Policy Choice for Ontario's Cadaveric Organ Shortage
Keywords: presumed consent
organ donation

Established within the context of a severe shortage of organs and tissues for transplantation, this thesis explores whether presumed consent for cadaveric organ donation is a legitimate policy choice for Ontario. The medical, legal and social reasons underlying organ scarcity and increased demand for transplantation are examined, and the shortcomings of Ontario’s current express consent system are analyzed. The various criticisms of presumed consent are also explored, including concerns with respect to its effectiveness, level of public support and implications for personal autonomy. Although the Citizens Panel on Increasing Organ Donations recommended against enacting presumed consent legislation, it is argued that the Panel was too dismissive of this concept given a perceived lack of public support. It is concluded that presumed consent can meet the concerns of critics, and that as part of a broader strategy could significantly increase the number of cadaveric organ and tissue donors in the province.
Challenging Exclusion: A Critique of the Legal Barriers Faced By Ethno-Racial Psychiatric Consumer/Survivors in Ontario
Keywords: Mental Health law, Race, Disability, Ethno-Racial
Consent and Capacity Board

This thesis identifies and analyzes the legal barriers faced by ethno-racial psychiatric consumer/survivors in Ontario, through an analysis of the Consent and Capacity Board (CCB). I employ interdisciplinary research to test the hypothesis that factors such as race, ethnicity, culture, poverty and social exclusion are not fully addressed by the CCB. To critique the CCB, I developed a theoretical framework using the grounded theory approach, in combination with tenets of disability theory, critical race theory and intersectionality. I used the theoretical framework to analyze qualitative research involving twenty interviews of stakeholders including lawyers, psychiatrists, CCB adjudicators, mental health service providers and ethno-racial psychiatric consumer/survivors. The analysis revealed the procedural, systemic/structural and discretionary barriers within the CCB’s pre-hearing, hearing and post-hearing process. Barriers were the result of cultural misunderstandings, misdiagnosis, complex familial relationships, culturally inappropriate care, institutional racism, poverty, discrimination and the CCB’s “color blind approach.” I conclude with prioritized recommendations.
Sub-acute Hippocampal Atrophy in the First Year Following Moderate to Severe Traumatic Brain Injury
Keywords: TBI
MRI
atrophy
sub-acute

Rationale: Ng et al. (2008) demonstrated that sub-acute hippocampal atrophy occurred between 4.5 and 24 months following moderate-to-severe traumatic brain injury (TBI); it remains to be determined if atrophy occurred before 24 months. Objectives: (1) to determine if sub-acute hippocampal atrophy occurs by the first year of injury; (2) to determine associated clinical and demographic variables. Methods: Ten moderate-to-severe TBI patients underwent MRI at 5 and 12 months post-injury. Glasgow Coma Scale (GCS) and demographic variables were correlated with change. Results: Significant hippocampal volume decreases were observed for right (P< 0.002, Cohen’s d= 0.34) and left (P< 0.036, Cohen’s d= 0.22) sides. GCS was significantly correlated with right (r= -0.663, P< 0.037), but not left percent hippocampal volume change (r= -0.327, P< 0.356). No significant correlations were observed for demographic variables. Conclusion: Sub-acute hippocampal atrophy occurs between 5 and 12 months post-injury and is associated with injury severity.
Saproxylic Insect Communities in Boreal Mixedwoods of Northeastern Ontario as a Function of Variation in Woody Debris Quality and Quantity and Sampling Methods
Keywords: saproxylic
boreal
insects
woody debris
sampling methods
soil insects

Saproxylic insects rely on dead or dying wood at some point in their development and appear to be sensitive to forest management. In 2005 and 2006, I sampled saproxylic insects in mixedwood boreal forests in northeastern Ontario to assess effects of: 1) different logging practices, 2) variations in woody debris (WD) qualities, and 3) different sampling methods. I also compared insect communities between heavily decayed WD and soil. Although I collected data on all arthropod orders, I focused on the families of the Diptera and parasitic Hymenoptera and the morphospecies of the Scelionidae and Diapriidae. These insects showed clear responses to the WD quality treatments, but not to the different logging treatments. A few families were affected by ex situ sampling. I also found that the faunas of soil and WD are rather distinct from each other. This study shows that WD is a source of forest biodiversity. Consequently, sustainable forest management will rely on studies like this to conserve and maintain the biodiversity of Canada's largest group of eco-zones.