VictorJuiz/thesis huggingface dataset:
Organophosphate Esters (OPEs) as Emerging Contaminants in the Environment: Indoor Sources and Transport to Receiving Waters
Keywords: Flame Retardants
OPE
Organophosphate Esters
SPF
Spray Polyurethane Foam Insulation
TCPP

Organophosphate esters (OPEs) are high usage chemical additives that are of increasing concern because of growing evidence of potential toxicity and ubiquitous occurrence in the environment. This thesis summarizes the analysis, sources and environmental abundance of OPEs using Toronto as a case study. This was accomplished by documenting concentrations, loadings and factors influencing 19 OPEs in three Toronto streams during high and low flow periods, final effluent from three waste water treatment plants (WWTP), urban rain and near shore water from Lake Ontario. Tris (2-chloropropyl) phosphate (TCPP) was found at the highest concentrations in streams and WWTP effluent. Estimated mass loadings showed that WWTP discharges contributed significantly to the mass of OPEs entering into nearshore Lake Ontario, however, streams and rain could contribute equal or higher loadings during wet periods. These results suggested two major pathways to Lake Ontario: direct discharge from WWTP; and atmospheric deposition and wash-off into streams.
Examining Factors of Physical Activity Participation in Youth with Spina Bifida using the Theoretical Domains Framework
Keywords: Spina Bifida
TDF

Spina Bifida (SB) is a congenital neural tube defect that involves the incomplete development of the spinal cord, resulting in varying health ailments. Given the high rate of inactivity reported for youth with SB and using the Theoretical Domains Framework as a guide, the purpose of this study was to explore the physical, psychological, social and environmental factors influencing physical activity (PA) participation in this population. Nine eligible youth (6 females; mean age = 15.9 years) took part in one, semi-structured individual interview. Subjects most commonly reported self-efficacy, positive consequences of PA, positive affect and social influences as perceived PA facilitators. Pain/fatigue, lack of control over decisional processes, lack of time and inaccessible environmental resources were the most commonly reported perceived PA barriers. These findings can be used to direct further research, testing the theoretical correlates that are most amenable to change in order to promote PA within this population.
Characterizing the Role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible poly-ADP-ribose Polymerase (TIPARP) in Estrogen Receptor Signalling
Keywords: Estrogen
Estrogen Receptor
Nuclear transcription factors
Receptor Signalling
TIPARP

Estrogens exert their effects by activating estrogen receptor alpha (ERα) and beta (ERβ). A number of different co-regulator proteins regulate the activities of both receptors. Identifying new ER co-regulators could lead to improved treatments for diseases, such as breast cancer. This study aimed to characterize the role of TIPARP, a mono-ADP-ribosyltransferase and novel co-regulator of ERs. Gene expression and ChIP studies revealed that TIPARP mRNA levels were regulated by ERs, and that ERα was recruited to TIPARP. TIPARP in turn repressed ERα, but co-activated ERβ activity. Furthermore, TIPARP was recruited to the regulatory regions of estrogen target genes. TIPARP mono-ADP-ribosylated both ERα and ERβ and reversed the effects of the mono-ADP-ribosylase, MacroD1, on ERα/β transactivation. Taken together, this work showed that TIPARP is a mixed function co-regulator of ERs, revealing that TIPARP and MacroD1 dynamically regulate the activities of ERα/β through ADP-ribosylation.
Possibilities and Challenges in Designing Knowledge Building Environments for Secondary School Mathematics
Keywords: education
knowledge building
mathematics

This research sought to introduce Knowledge Building pedagogy into Ontario secondary school mathematics classes to explore the extent to which discourse aimed at deep understanding could improve math understanding. The thesis describes two design initiatives, first with two grade 9 then two grade 10 classes. In each context students generated diverse mathematical ideas, supported theories with evidence, and requested evidence from peers, with several grade 10 students showing evidence of improving earlier ideas (a key principle of Knowledge Building) . However, implementing Knowledge Building pedagogy required superimposing sustained student-directed discourse on current assessment procedures and syllabus timelines, which created anxiety especially among grade 10 students, who feared negative impact on test performance. Limited student engagement thus precluded establishment of Knowledge Building communities. Results suggest systemic change is needed to address cultural expectations, to introduce new knowledge media that fosters collective and individual achievement, and to realize studentsâ capacity for Knowledge Building in mathematics.
Control of Cardiomyocyte Proliferation by p53/MDM2-Regulated microRNAs
Keywords: Cardiology
Cell Cycle
MDM2
microRNA
p53
Tumor Suppressor

Defining the roadblocks responsible for adult cardiomyocyte cell cycle arrest lies at the core of developing cardiac regenerative therapies. Inactivation of the p53/MDM2 tumor suppressor circuitry in the heart caused a significant increase in cardiomyocyte proliferation, through an upregulation of factors involved in cell cycle re-entry. These factors may be regulated by microRNAs (miRNAs), in quiescent cardiomyocytes. Therefore, we hypothesized that inactivation of p53/MDM2-regulated miRNAs could promote the expression of cell cycle activators and induce proliferation of cardiomyocytes. Comparison of miRNA expression profiles from cardiac specific p53/MDM2 double knockout (DKO) mouse hearts and wild type controls revealed 11 miRNAs that were downregulated in the "proliferative" DKO hearts and enriched for mRNA targets involved in cell cycle regulation. Knockdown of these 11 miRNAs in neonatal rat cardiomyocytes significantly increased the occurrence of cytokinesis, revealing a novel subset of p53/MDM2-regulated miRNAs responsible for maintaining cell cycle arrest in the heart.
A Qualitative Exploration of Pain among Mixed Martial Artists
Keywords: Emotional Contagion
Ethnographic Case Study
Mixed Martial Arts (MMA)
Pain
Sport Psychology
Video Diaries

Athletes often experience pain in sport and in their everyday lives, yet little research has explored how athletes form understandings of pain, and how social interactions contribute to athletes’ understandings of pain. The purpose of this study was to explore MMA fighters’ experiences of pain while training for fight. A multiple case study approach (Stake, 1995) was used to study pain among four amateur and professional fighters and their training partners (total N = 7). Data were collected longitudinally using semi-structured interviews, participant observation, athlete video diaries, and video recordings of training sessions and fights. Results pertained to: (a) distinguishing between physical pain, injury, and emotional pain; (b) social validation of pain; (c) giving and receiving pain; (d) sharing pain with teammates; and (e) reflections on ‘doing’ pain research. The results suggest that pain experiences are socially constructed and shared with others, and teammates influence how fighters understand their pain.
Patient-level Social Determinants of Unplanned Hospital Readmission among General Internal Medicine Patients
Keywords: General Internal Medicine
Healthcare Quality
Hospital Readmission
Risk Factors
Sociodemographic

Hospital readmissions have garnered considerable attention among researchers, clinicians, and policy-makers because they are common, costly, and potentially preventable. The purpose of this study was to understand whether patient-level socio-demographic factors are independently associated with 30-day readmission among General Internal Medicine (GIM) patients. This retrospective cohort study included 1427 patients discharged from the GIM service of an urban teaching hospital in Toronto, Canada between the years 2012 and 2014. Multivariable Cox regression was used to analyze relationships between 13 socio-demographic variables and 30-day unplanned all-cause readmission while controlling for validated clinical risk factors. Socio-demographic factors were not found to be significantly associated with readmission within this cohort. Factors related to illness-level, particularly previous hospital utilization, were significantly associated with readmission. Knowledge generated from this study may inform the efforts of clinicians, hospital managers, and policy makers working to reduce hospital readmission rates and develop health systems which facilitate population health equity.
Early Palliative Care: Opinions & Attitudes of Canadian Palliative Care Physicians
Keywords: Early Palliative Care
Palliative Care
Palliative Care Physicians
Supportive Care

Our aim was to describe Canadian palliative care physiciansâ attitudes and opinions about early palliative care and to determine factors associated with receiving early referrals. The response rate was 71% (531/747); 48% (257/531) were SPC physicians. The majority reported that for cancer (93.9%) and non-cancer (90.2%) patients, referral to palliative care should ideally be early. Only 20.5% reported the average survival for patients referred to them was >6 months. Having completed a Masters/PhD (OR 2.5, 95% CI 1.1-5.5); providing care mainly for non-cancer patients (4.0, 1.3-12.3); and female sex (2.7, 1.2-6.2) were associated with receiving early referrals. Those agreeing that patients should have stopped all chemotherapy before palliative care referral (0.34, 0.16-0.73) were less likely to receive early referrals. We conclude that timing of referral may be related to characteristics of the receiving physician rather than only the referring physician.
Mechanisms of an Exaggerated Blood Pressure Response to Exercise in Middle-age Endurance-trained Athletes
Keywords: Blood Pressure
Cardiovascular
Endurance Athlete
Exercise
Hypertension

An exaggerated blood pressure response (EBPR) to exercise is associated with an increased risk of latent-hypertension. Few data describe the mechanisms that contribute to the exercise blood pressure (BP) response in a middle-aged endurance-trained cohort. We hypothesized that alterations in vascular and autonomic function may contribute towards the EBPR. 40 middle-age endurance-trained athletes underwent maximal graded exercise testing with concurrent BP measurements. 22 subjects had a peak systolic BP â Ľ median and 18
Prevalence and Factors Associated with Vertebral Fractures in Psoriatic Arthritis
Keywords: BMD
Epidemiology
fragility fractures
Inflammation
Osteoporosis
Spondyloarthritis

Osteoporosis and fractures are common comorbidities in inflammatory arthritis. Osteoporosis prevalence in psoriatic arthritis (PsA) is not known. I aimed to synthesize current evidence by conducting a systematic review of the literature and determine the prevalence and factors associated with radiographic vertebral fractures in PsA patients. A systematic review of literature, conforming to PRISMA guidelines, synthesized inconsistent and non-conclusive evidence pertaining to presence of osteoporosis and fractures in PsA. Vertebral fractures were identified by quantitative morphometric assessment on lateral spinal radiographs of lumbar (L) and thoracic (T) spine (T6-L4) after demonstrating a high inter- and intra-assessor reliability. Covariates including demographic features, measures of disease activity, body mass index and pharmacologic treatment were investigated as associated factors. We found a low prevalence of vertebral fractures in PsA (5.3%). Age (OR 1.08, 95% CI [1.04, 1.12], P
Investigating Lysosomes and Protein Degradation Pathways for the Treatment of Congenital Muscular Dystrophy Type 1A
Keywords: autophagy
congenital muscular dystrophies
lysosomes
MDC1A
therapy development
zebrafish

Congenital muscular dystrophy type 1A (MDC1A) is the most common congenital muscular dystrophy in Western countries. The goal of our lab is to identify potential therapies for MDC1A that can be translated into clinical use. Previously, we observed lysosome redistribution in muscle biopsies from human MDC1A patients. Here, we corroborate this observation by documenting lysosome redistribution to the myosepta in the zebrafish model of MDC1A, candyfloss (caf); however we show that manipulating the membrane-repair and membrane-fusion capacity of lysosomes with chemicals does not appear to have therapeutic potential. Alongside these experiments, we tested chemicals that had previously been explored in mouse models of MDC1A and found that MG132, a proteasome inhibitor, partially ameliorates disease pathology in caf mutants. Further investigation into the mechanisms by which MG132 functions in zebrafish, as well as targeting other aspects of lysosome function, will provide important insights into potential treatments for this debilitating muscle disease.
Veering towards Virulence: Modelling the Evolution of HIV-1 in Response to Prophylactic Drugs
Keywords: adaptive dynamics
antiretroviral therapy
evolution
HIV
preexposure prophylaxis
virulence

Average virulence in HIV is on the rise in several highly treated populations. The drivers of this evolution are not known, but evolutionary theory suggests that imperfectly effective med- ical interventions can select for higher virulence. Previously developed mathematical models predict that HIV treatment leads to the evolution of lower virulence, but have not accounted for the fact that treated hosts sometimes transmit their infections. Here, we use an evolutionary invasion analysis to show that higher virulence evolves with the increasing use of drugs that imperfectly treat and prevent HIV infection (i.e., antiretroviral therapy and pre-exposure prophylaxis, respectively). As a consequence, untreated infections progress more rapidly to AIDS, and the prevalence of infection in host populations increases. These findings suggest that antiretroviral drugs may have under-appreciated evolutionary consequences that threaten their benefit, and we caution that virulence evolution should be closely monitored as access to these drugs continues to improve.
Dynamics of the Association of Heat Shock Protein HSPA6 (Hsp70B') and HSPA1A (Hsp70-1) with Stress-sensitive Cytoplasmic and Nuclear Structures in Differentiated Human Neuronal Cells
Keywords: FRAP
Heat shock proteins
HSPA1A
HSPA6
Live imaging
SH-SY5Y

The widely studied HSPA1A is a heat shock protein that counters the effects of protein misfolding. The little studied HSPA6 is present in the human genome and absent in mouse and rat, hence missing in current models of neurodegenerative diseases. Differentiated human neuronal SH-SY5Y cells were used to compare the dynamics of the association of YFP-tagged HSPA6 and HSPA1A with stress-sensitive sites by employing Fluorescence Recovery After Photobleaching (FRAP). Following thermal stress, HSPA6 displayed a prolonged and more dynamic association, compared to HSPA1A, with centrioles that play critical roles in neuronal polarity and migration. HSPA6 and HSPA1A displayed similar FRAP kinetics with nuclear speckles and the nucleolus. Subsequently, HSPA6, but not HSPA1A, localized with the periphery of nuclear speckles, and displayed the greatest dynamism compared to interaction with other targets. This suggests involvement of HSPA6 in transcriptional recovery of differentiated human neurons from cellular stress not apparent for HSPA1A.
Becoming Antiquities: How Museum Objects Gain Educational and Heritage Value
Keywords: Archaology
Education
Heritage
Museum process
Object biography
Value

This thesis looks at the processes that change the roles of museum objects throughout their lifetime and the resulting effects on the value of objects. Using Object Biography and Actor-Network Theory as theoretical frameworks and two museum collections, a biography of the lives of these collections was created. The biographies examine a specific portion of the collectionsâ lives from the time they were excavated to their present state as museum collections; as well, they were used as a tool to pinpoint key diversions that represented a change in roles and value for the collections. The analysis of the biographies and the resources consulted revealed patterns and relationships between the type of diversion, the actors involved, the affective weight of the collections and the types of value that were affected. Interaction between actors and objects was found to bring about the greatest amount of change in roles and value.
Dentofacial Morphology in Obese and Non-obese Children with and without Obstructive Sleep Apnea
Keywords: Craniofacial
Dentofacial development
Orthodontics
Respiratory Medicine
Sleep Medicine

Introduction: Several craniofacial abnormalities have been suggested to contribute to obstructive sleep apnea. These characteristics vary significantly among the literature and are limited by the infrequent use of polysomnogprahy, the gold standard for diagnosing and quantifying obstructive sleep apnea. Objective: To compare the prevalence of facial and/or dental imbalances in children with and without obstructive sleep apnea in cohorts of obese and non-obese children. Methods: A prospective, cross-sectional study of children (ages 4-16) who were referred for a polysomnogram at The Hospital for SickKids. Facial features and malocclusion was assessed clinically by one dentist, blinded to the PSG results. Results/Conclusions: Horizontal excess (overjet) was the only dentofacial finding which was significantly more common in children with obstructive sleep apnea as compared to those without obstructive sleep apnea (p=0.04). Dentofacial characteristics were also not different between children using positive airway pressure therapy and children not on positive airway pressure therapy
Neurobiological Mechanisms by which Stress Prevents Empathy
Keywords: emotional contagion
empathy
pain
rodent empathy
social neuroscience

Mice have the capacity to transmit pain status amongst familiars, which is understood to represent empathy in rodents. Recent findings show that the stress of a social interaction with an unfamiliar mouse can block empathy, while inhibiting the endocrine stress response of unfamiliar mice can evoke it. Experiments were conducted on na誰ve male CD-1 速 mice and found higher pain responses when familiars were tested together as opposed to with strangers. Western blot analysis demonstrated higher glucocorticoid activity in empathy involved regions (prefrontal cortex and anterior cingulate cortex) of mice in the unfamiliar condition compared to the familiar condition. The administration of Metyrapone (to block stress response) before testing resulted in higher pain responses in unfamiliars compared to isolated mice however no significant difference was found between Metyrapone pretreated unfamiliars and saline pretreated unfamiliars. These findings begin to uncover the neurobiological mechanisms by which stress prevents empathy using rodent models.
Mix Development of PLC-based Ultra-high Performance Fibre Reinforced Concrete and Characterization of Key Mechanical Properties and Time-Dependent Behaviour
Keywords: Concrete
Fibre
Flexural
Mix design
Tensile
Ultra-high performance

This thesis proposes a new Ultra-high Performance Fibre Reinforced Concrete (UHPFRC) mix design developed and optimized with the aim of lowering environmental and economic cost while achieving better performance. Instead of plain Portland Cement, the proposed mix uses Portland Limestone Cement (PLC) with 6-15 % of limestone, as a means to reduce the gross cement content. The optimized mix design features 10% of silica fume and 30% of ground granulated blast-furnace slag, 2.5% of steel fibres by the total volume, and very low water-to-binder ratio. The proposed mix is validated and characterized through a comprehensive experimental program, which shows that at 56 days the proposed mix can achieve a compressive strength at least 130 MPa, an average peak flexural stress of 27 MPa, and an average peak uni-axial tensile strength of 10 MPa. Tests also show that the proposed mix has satisfactory performance in shrinkage, resistance of chloride ion penetration, and freeze-thaw resistance.
Multiphysics Design Optimization of Microwave Ablation Antennas
Keywords: Antenna
Electromagnetics
Microwave Ablation
Multiphysics
Optimization

Microwave ablation is based on localized heating of biological tissues, enabled by an electromagnetic field. Antennas for ablation are commonly designed in a forward approach to generate a particular Specific Absorption Rate profile within the target. However, little attention has been dedicated to designing antennas inversely, to allow controllable synthesis of temperature profiles customized for the application. Also, most existing designs do not account for thermal inhomogeneities in tissue. An inverse, multiphysics methodology for microwave ablation antenna design is presented herein, that involves optimizing the antennaâ s current distribution to synthesize a desired temperature profile, while accounting for heat diffusion. The results indicate and quantify the clear advantages of this multiphysics approach. This methodology is successfully applied towards designing an easily configurable printed dipole microwave ablation antenna that addresses several limitations of existing designs. This design provides the functionality of a phased array, and allows controlled synthesis of temperature profiles.
The Causes and Consequences of Plant Defence Evolution
Keywords: Adaptive cline
Plant defense
Plant reproduction
Trifolium repens
Urbanization
White clover

Many plant species have evolved chemical defences to reduce herbivory. I studied two aspects of the evolution of plant defence using the cyanogenesis system in Trifolium repens, white clover, as a model. First, I investigated whether cyanogenesis altered natural selection on reproductive characters. In this study, I found that the genetic variation for cyanogenesis can drastically alter natural selection on floral traits. This result suggests that the evolution of plant defence and floral traits may be interrelated. Second, I investigated the factors that drive patterns of antiherbivore defence evolution in urban environments. I observed adaptive clines in cyanogenesis in three North American cities, and identified natural selection during the winter as being the key determinant of this cline. This result highlights a novel mechanism through which humans can drive adaptive evolution in natural populations. Together, these results highlight novel processes that cause and follow the evolution of plant defences.
Language Education in Maasai Land, Tanzania: Parental Voices and School Realities
Keywords: English
Maasai
parent perspectives
public/private schools
Swahili
Tanzania

This research explores parental perspectives on language education in Maasai Land, Tanzania, and the ways in which school realities at a Swahili-medium government (SMG) school and an English-medium private (EMP) school align with and diverge from parental expectations. While significant research shows benefits of Swahili-medium schooling in Tanzania, many parents are clamouring for English-medium private primary schools, while the 130+ local languages are muted in formal schooling. This study employs interviews with parents at one SMG and one EMP, and school observations at these same schools, to explore and compare valuations, expectations for use, and use of Maa, Swahili and English. This research finds that parents are generally very supportive of multilingual education, with perspectives both reflecting and rejecting dominant political discourses shaped by nationalism and neoliberalism. Schoolsâ orientations towards languages as problems or resources are shaped by symbolic and economic valuations of languages in Tanzaniaâ s broader political economic context.