VictorJuiz/thesis huggingface dataset:
X-ray and Magnetic Resonance Imaging (MRI) Fusion to Guide Clinical Revascularization of Peripheral Chronic Total Occlusions (CTOs)
Keywords: Femur
MRI
Peripheral
Registration
Revascularization
X-ray

Percutaneous transluminal angioplasty (PTA) is a minimally invasive procedure used to revascularize blocked arteries of the heart and peripheries. However, endovascular approaches to treat chronic total occlusions (CTOs) of the superficial femoral artery (SFA) have proven challenging due to the presence of long and multiple occlusions, which cannot be visualized under x-ray fluoroscopy (XRF) alone. Devices can exit the artery leading to severe perforation. Magnetic resonance imaging (MRI) can produce three-dimensional vascular maps that are sufficient to identify the lesion extent and characterize the surrounding vasculature. Higher PTA success rates could be achieved for lengthy occlusions by merging 3D MRI data and XRF. This thesis develops a 3D MRI to 2D XRF registration method to guide revascularization of peripheral CTOs. The registration method utilizes bones in the MR and x-ray images as landmarks for registration. Furthermore, using an edge-based similarity measure the algorithm automatically maintains alignment together with C-arm tracking.
Gestational Diet Folic Acid Content and Development and Function of Food Intake Regulation in Rats
Keywords: Childhood Obesity
Fetal Programming
Folic Acid
Food Intake Regulation
Hypothalamus
Neurons

High folic acid consumed during pregnancy promotes characteristics of metabolic syndrome in rat offspring. We hypothesized that folic acid alters the development of hypothalamic food intake pathways in utero, contributing to the metabolic phenotype of the offspring in later life. Pregnant Wistar dams were fed modified AIN-93G diets containing folic acid at: 0, 1.0 (control), 2.5, 5.0, or 10.0-fold of the recommended level. The folic acid content in the gestational diet was reflected in the expression of neuropeptide Y (NPY) neurons and body weight of the male offspring at birth. Low and high gestational folic acid led to higher food intake and weight gain in the offspring to 9 weeks post-weaning, consistent with decreased activity of pro-opiomelanocortin (POMC) neurons. The folic acid content in the gestational diet affects in utero development of hypothalamic feeding circuits and contributes to a phenotype that reflects characteristics of the metabolic syndrome in the offspring.
An Immune-Deficient Prkdc Knockout Rat Model of Perinatal Hypoxic-Ischemic Brain Injury for Future Xenograft Studies
Keywords: hypoxia ischemia
model characterization
perinatal
prkdc knockout
rice vannucci
xenograft

Perinatal hypoxia ischemia (HI) is a significant cause of brain damage leading to motor and cognitive impairments. There are no treatments that can repair the damage and improve outcomes, though preclinical research using neural precursor cell (NPC) transplantation as a therapy has shown promise. To promote clinical translation, it is essential that human-derived NPCs also be tested in animal models. To reduce the risk of xenograft rejection, we characterized a model of HI injury in immune-deficient Prkdc knockout rats. Knockout HI rats displayed sensorimotor deficits on the cylinder and pasta-handling tests, and reductions in size of and cellular loss in the hippocampus, cortex, and corpus callosum. Ventriculomegaly and grey matter gliosis were also prominent. Interestingly, knockout rats displayed overall more severe injuries than wildtype littermates. This model characterization will allow for future studies of human-derived NPCs in the rodent brain, paving the way for the clinical translation of this therapy.
Balance Control when Ascending and Descending Stairs of Different Architectural Designs
Keywords: architectural designs
balance control
biomechanics
center of mass
stair walking
vision

The purpose of this study was to understand differences in balance control during stair walking on stairs of different architectural designs under varying visual conditions and lighting conditions. An 8-step custom made staircase with removable covers permitted evaluation of stair ambulation. Individuals ascended and descended the staircase under two visual conditions (normal vision, and suboptimal vision), two lighting conditions (bright light and low light) and three architectural stair design conditions (glass treads, open wood risers, and closed wood risers). The main findings of the study showed that older adults positioned their centre of mass further back from the step edge and displayed larger margins of stability across all conditions. In addition, both young and older adults displayed larger margins of stability under the glass stair condition compared to the other stair designs and under the low lighting condition compared to the bright light.
The Effect of Maternal Vitamin B12 Status in Combination with High Folate Status on Gene-Specific DNA Methylation in Cord Blood Mononuclear Cells
Keywords: cord blood mononuclear cells
DNA methylation
folate
gene expression
pregnancy
vitamin B12

DNA methylation is an important epigenetic determinant in gene expression, with potential consequent effects on disease susceptibility. Maternal folate and B12 has the potential to modulate DNA methylation via the provision of S-adenosylmethionine. Using the Illumina Infinium MethylationEPIC array, we found lower genome-wide (-0.0059±0.0147, p=0.013) and gene-specific (p=0.007) DNA methylation in genes influenced by maternal low serum B12 and high RBC folate concentrations at early pregnancy. Analyses using Ingenuity Pathway Analysis and ddPCR determined that B12 and folate-induced DNA methylation changes altered expression of functionally relevant genes related to metabolism and development. Infants born to mothers with a low B12 status are shown to have larger infant anthropometric measures. Our data suggest that low B12 and high folate induced DNA methylation changes in the developing fetus. Given the potential for these changes to mediate disease risk later in life, future large-scale studies are warranted to confirm our exploratory findings.
Hyperphosphorylated Tau as a Novel Biomarker for Traumatic Axonal Injury in the Spinal Cord
Keywords: Axonal injury
Biomarker
Hyperphosphorylation
Spinal cord injury
Tau
Trauma

The tau protein is a focus of biomarker research for spinal cord injury (SCI). Brain injury studies have demonstrated that hyperphosphorylation of tau (p-tau) occurs within injured axons and can be used as a biomarker; however, the potential of p-tau as a biomarker for SCI is not yet known. Therefore, the present study determined whether tau is hyperphosphorylated within injured spinal cord axons and whether p-tau levels increase in cerebrospinal fluid (CSF) and serum after an experimental SCI in rats. Severe SCI at T8 showed the presence of p-tau in damaged axons with a similar time-course and distribution pattern to β-amyloid precursor protein, a biomarker of axonal injury. CSF levels of p-tau and total-tau significantly increased at 1 day post-SCI, however, only serum p-tau levels were significantly elevated in SCI rats compared to naïve rats. These results suggest that CSF and serum p-tau may be a useful biomarker for severe traumatic SCI.
Analysis of Drosophila Nervous System Development Following a Brief Exposure to Ethanol
Keywords: Axon Guidance
Drosophila
Fetal Alcohol Spectrum Disorders
Serum Response Factor

Improper neuronal mapping predisposes many of the neurodevelopmental deficits that arise in patients of Fetal Alcohol Spectrum Disorders (FASD). Here I used Drosophila embryos as a model to investigate the neuronal defects that arise after exposure to ethanol. Drosophila is an excellent model for studying the mechanisms underlying FASD due to their vulnerability to the toxic effects of alcohol and the ease of manipulating their development. Using this model, I was able to provide detailed morphological analyses of the effects of a brief ethanol exposure on Drosophila neural development. I also examined the mechanisms that may regulate the FASD phenotype, specifically the serum response factor (SRF) signalling pathway. SRF signalling regulates numerous functions in the nervous system, including neuronal growth and migration. Through SRF manipulation in Drosophila, I was able to show that SRF is necessary for proper Drosophila axonogenesis, and that it may contribute to the FASD phenotype.
A Low-Power Sub-GHz RF Receiver Front-End With Enhanced Blocker Tolerance
Keywords: Blocker Tolerance
Class-AB
IEEE 802.15.4
Low-power
RF Receiver
Sub-GHz

Sub-GHz wireless systems have become a popular choice for Internet-of-Things (IoT) applications due to their lower cost, lower power consumption and longer transmission range compared to their 2.4 GHz counterpart. This thesis presents a class-AB sub-GHz RF receiver front-end for low power IoT applications. By exploiting transistors' class-AB operation in both the RF and baseband sections, the receiver front-end achieves a very low sensitivity and an elevated blocker tolerance while keeping a low power consumption. Such performance makes the receiver fully compliant with the short-range (e.g. IEEE 802.15.4) application and also suitable for the emerging long-range (e.g. LoRa) application. The proposed RF receiver front-end has been implemented in 0.13um CMOS technology, operates in the 868/915MHz ISM bands, and exhibits an in-band gain of 50dB, noise figure of 2.7dB, out-of-band IIP3 of +2dBm, out-of-band IIP2 of +37dBm, out-of-band P1dB of -10.5dBm, while draining 2.1mA from a 1.2V supply.
Population Genomics of Transposable Elements and their Effect on Gene Expression Variation
Keywords: Gene expression
Genomics
Population genetics
Transposable elements

Transposable elements (TEs) make up a significant portion of eukaryotic genomes, and thus are important drivers of genome evolution. The forces controlling TE copy number and the extent to which TEs affect phenotypic variation genome-wide are still unclear. I characterised TE insertion polymorphism in 124 whole genome sequences from a single population of Capsella grandiflora. The frequency of insertions is negatively correlated with distance to genes, as well as density of non-coding conserved elements, suggesting that the negative effects of TEs on gene regulation are important in limiting their spread throughout the population. Rare TE variants strongly influence gene expression variation, predominantly through downregulation. Contrarily, rare single nucleotide polymorphisms (SNPs) contribute equally to upregulation and downregulation, but have a weaker overall effect. Taken together, these results imply that TEs contribute significantly to gene expression variation and can be more likely than rare SNPs to cause extreme changes in gene expression.
The Spatiotemporal Distribution of SPARC and Collagen IV in the Secretory Pathway and Evidence of a Functional Relationship During Extracellular Collagen IV Polymerization
Keywords: Collagen IV
Drosophila
Extracellular matrix
SPARC

Basement membranes (BMs) are a hallmark feature of multicellular organisms and support essential developmental events. Collagen IV is the major structural component of BMs, however, its spatiotemporal assembly into stereotypic lattice networks is poorly understood. SPARC, a collagen IV-binding glycoprotein, is enriched in BMs of Drosophila melanogaster. SPARC is hypothesized to be an extracellular chaperone-like protein, whereby it prevents premature collagen IV polymerization. In this study, I demonstrate that SPARC and collagen IV co-localize primarily in the trans-Golgi network prior to secretion. Moreover, SPARC reduces premature nucleation of collagen IV molecules in cultured hemocytes seeded on a laminin matrix, but is not required for the establishment of collagen IV-rich BMs in the embryo. To gain further insight on the functional relationship between SPARC and collagen IV, CRISPR/Cas9 sparc mutants were generated. This genetic tool will be used to unmask SPARC structural domains responsible for collagen IV assembly and BM homeostasis.
Quantum Mechanical Characterization of Substrated Bilayer Graphene for Future Supercapacitor Applications
Keywords: Density Functional Theory
Electrochemistry
Energy Storage
Graphene
Interfacial Physics
Supercapacitors

Energy storage is one of the most crucial ingredients of a sustainable energy future. The safety, reliability, and performance of storage devices present a number of design challenges that require developing accurate predictive models capable of representing the most relevant physical phenomena at various spatial and temporal scales and a reasonable computational cost. Moreover, the current trend of decreasing the device size and the advent of low-dimensional nanomaterials have increased the dominance of interfacial physics that cannot be accurately modelled as a continuum within the device. This thesis is a first step towards developing a methodology for characterizing interfaces in capacitive energy storage devices based on insights from Density Functional Theory. Monolayer and bilayer graphene electrodes, attached to nearly lattice-matched conducting substrates, are then modelled as case studies. Graphene is one of the most promising materials for future supercapacitors due to its high specific surface area and unique electronic properties.
Jet Oscillation in Abrasive Slurry-Jet Machining as a Function of Polymer Concentration and Nozzle Geometry
Keywords: Jet Oscillation
Machining
Viscoelasticity

This thesis investigated the effects of polymer concentration and nozzle design on jet stability for polymeric abrasive slurry-jet channel machining in glass. Conical nozzle contractions, having angles of 180°, 60°, 30°, and 20°, were used with aqueous polyethylene oxide (PEO) polymer solutions, having concentrations of 100, 200, and 300 ppm. Channels were machined in glass using slurries containing 1 wt% of 10 μm aluminum oxide particles, made from the same four working fluids used to study jet oscillation. Jet oscillation was found to increase nonlinearly with polymer concentration for all contraction geometries. As a result of the effect of the varying degrees of jet oscillation, a clear relationship was found between the polymer concentration and the channel width. Flow visualization within the nozzle confirmed the presence of vortices that have been associated with jet instability, but did not reveal a clear reason for the changes in jet stability.
Participants’ Perspectives on Ethical Issues in Arts-Based Health Research: A Qualitative Study
Keywords: arts-based health research
arts-based methods
constructivist grounded theory
participant perspectives
qualitative research
research ethics

Arts-based health research (ABHR) is a novel qualitative approach that uses different art forms to conduct health research. Despite the growth of ABHR, ethical consideration has been significantly lacking. More importantly, participants’ perspectives on ethical issues in this co-constructive and collaborative approach are absent. From a constructivist-interpretivist stance, factors incorporated in participants’ decision-making concerning ethical issues in ABHR were investigated to construct their perspectives on ethical issues in ABHR. Using constructivist grounded theory, 10 participants from an urban arts charity organization were interviewed, and three major factors were constructed: identities as artists, art is a story, and art is to express. An overarching theme called respect for the artist was also constructed to illustrate how these factors influence participants’ perspectives on ethical issues in ABHR. Findings of this study contribute to informing researchers, REBs, and guideline development for ABHR to better meet the needs of participants as they articulate them.
1,1-Hydroboration and Borane Adduct of Diphenyldiazomethane
Keywords: Diazomethane
Dinitrogen
Frustrated Lewis Pair
Hydroboration
Main Group Chemistry
Nitrogen Fixation

The advent of frustrated Lewis pair chemistry has demonstrated unique reactivity with a variety of small molecules. This thesis explores related chemistry with reactions of diazomethanes and highly electrophilic boranes. Diphenyldiazomethane Ph2C(N2) reacts with HB(C6F5)2 resulting in 1,1-hydroboration via a concerted reaction involving initial formation of the Lewis adduct, yielding the robust amino-borane product Ph2CN2BH(C6F5)2. Alternative synthetic routes to this product are detailed, as well as a related salt. Conversely, Ph2C(N2) reacts with B(C6F5)3 to form a highly sensitive adduct Ph2CN2B(C6F5)3. This product liberates N2 and is proposed to generate Ph2CB(C6F5)3. DFT calculations reveal that formation of this product is thermodynamically favourable from the starting compounds of carbene, N2 and borane. The isolation of this latter species opens the possibility that judicious choice of a Lewis acid and base could provide an avenue to metal-free fixation of N2.
Exploring the impact of the ECHO model™ in Ontario on primary healthcare providers sharing of chronic pain knowledge: A qualitative study
Keywords: Chronic Pain
eLearning
Knowledge Dissemination
Online Learning
Primary Care
telehealth

ECHO Ontario Chronic Pain/Opioid Stewardship (ECHO Ontario Pain) is a telehealth platform, which supports healthcare providers (HCPs, spokes) to manage patients with chronic pain in their communities, using specialists (hub). ECHO Ontario Pain is using this model to address challenges, such as dealing with a lack of knowledge about chronic pain and inappropriate opioid prescribing practices. Thirteen qualitative semi-structured interviews were conducted with HCPs from the program. Four themes developed: (1) experiences with chronic pain management before joining ECHO, (2) learning and sharing in the program, (3) the use of technology, and (4) recommendations for improvements. ECHO Ontario Pain was a novel way to provide education by demonstrating the effectiveness of participating in an online learning model. The study highlights the value of different learning approaches and how they affect HCPs interactions with their patients, their practices, and their wider community. Overall, these findings complement and add to existing ECHO research.
MiR-139 is a Predictor of Prostate Cancer Recurrence and Regulates Cancer Aggressiveness by Targeting IGF1R
Keywords: IGF1R
miR-139
miRNA
p21
prostate cancer
senescence

MiR-139 expression is significantly decreased in prostate tumours with an increased risk of recurrence and metastasis. We investigated the function and mechanism of miR-139 action in prostate cancer cells. Cell-based assays demonstrated that miR-139 decreased the proliferation and migration capabilities of prostate cancer cell lines. Luciferase assays indicated that miR-139 directly targeted IGF1R 3’UTR. This was confirmed through immunoblotting showing decreases in IGF1Rβ protein expression in miR-139 overexpressing cell lines. MiR-139 overexpressing cells exhibited a G2 cell cycle arrest and increased senescence. The induction of senescence was accompanied by decreased phosphorylated AKT and ERK proteins and increased p21 protein expression. Our results indicate that miR-139 decreases IGF1R expression, which prevents activation of downstream kinases AKT and ERK, leading to increased p21 expression concomitantly with senescence. This may represent a novel mechanism of growth suppression induced by miR-139 in prostate tumours.
Development of a Single-Cell Optical Control Technique
Keywords: Digital Multimirror Device
Electrophysiology
Neural Code
Optogenetics
Patch Clamp
Single Cell Control

Our brain encodes information via patterns of action potentials (APs) produced by neurons, referred to as the neural code. Studies of the neural code have shown two methods of information encoding: rate codes and temporal codes. Two of the major classes of interneurons in the neocortex, parvalbumin positive and somatostatin positive interneurons, have properties that may enable them to specialize in temporal and rate codes, respectively. However, the technology required to study neural code specializations has been out of reach until recently. In this thesis, I developed a system to use a digital multimirror device for patterned optogenetic stimulation. I demonstrate the system’s ability to control APs in individual neurons at physiologically realistic rates. Additionally, I demonstrate that in vivo-like patterns can be created for presynaptic activity in specific interneuron types in ex vivo brain slices. This system can be used in future studies of neural code specialization by interneurons.
Designing the HCI Living Curriculum
Keywords: HCI
HCI education
living curriculum

The Association for Computing Machinery (ACM) Special Interest Group on Computer-Human Interaction (SIGCHI) has been supporting research into Human-Computer Interaction (HCI) education for many years, most actively in the last six years. This thesis proposes the preliminary framework for a Community of Practice (CoP) of HCI scholars and educators, sharing and collaborating to develop teaching materials. Two studies were carried out. The first involved a set of 12 interviews with HCI educators and practitioners that examined requirements for the HCI Living Curriculum. The second study was a questionnaire with 28 respondents which carried out further requirements analysis. Based on the findings of the two studies, use cases and design requirements for the HCI Living Curriculum are presented. Guided by these use cases and design requirements, a prototype HCI Living Curriculum was then constructed. The thesis concludes with a discussion of lessons learned and prospects for future development of the Living Curriculum.
Mortality and Morbidity in Office-Based Deep Sedation and General Anaesthesia for Dentistry in Ontario
Keywords: dental anaesthesia
dental anesthesia
mortality and morbidity
office-based anesthesia

Objectives: To estimate the prevalence of mortality and serious morbidity for office-based deep sedation and general anesthesia (DS/GA) for dentistry in Ontario from 1996-2015. Materials Methods: Data were collected retrospectively in two phases. In Phase I, cases involving injury or death for dentistry under DS/GA, sourced from the Chief Coroner of Ontario and the Royal College of Dental Surgeons of Ontario were reviewed. Phase II involved a survey of all registered providers of DS/GA where they estimated the number of DS/GA administered. Prevalence was calculated using Phase I and Phase II findings. Results: The estimated prevalence of mortality is 0.8 deaths per 1 million cases, and the estimated prevalence of serious morbidity is 0.25 per 1 million cases. Conclusions: The mortality and morbidity rates found in this study fit within the lower end of the range of mortality and morbidity reported by similar studies for office-based DS/GA in dentistry.
Establishing Performance Limits at Ages that Are Appropriate for SCM Concretes
Keywords: Age limits for concrete performance
concrete performance
High-Performance concrete
Permeability prediction
Resistivity correlation

Early-age transverse cracking of High-Performance Concrete (HPC) bridge decks has become of a major concern to the Ministry of Transportation Ontario (MTO). However, the MTO’s early-age performance requirements result in suppliers and contractors using silica fume and increasing the total cementitious materials contents, making the HPC mixtures more susceptible to cracking problems. Also, the MTO’s 28-day performance limits do not provide an appropriate indication of the quality of these concretes which contain supplementary cementitious materials (SCMs). Therefore, this study investigates the statistical relationship at 28 and 56 days of age for concrete strengths and permeability ratings to determine the minimum 28-day values that would meet the MTO HPC design properties at 56 days. The results show the possibility to predict 56-day performance results based on conservative statistical analysis based on prequalification data. All test results are well within the MTO’s requirements.