VictorJuiz/thesis huggingface dataset:
Mental Health Service Use Patterns for Immigrant Groups in Ontario: Population Based Studies

Background: Immigrants have diverse pre-immigration, peri-immigration, and post-immigration experiences. Despite being exposed to distinct mental health stressors, little is known about immigrant groups' service use for non-psychotic mental health disorders in the host country.Objective: Three studies assessed mental health service use by recent newcomers who settled in Ontario, Canada compared to use by age-and-sex matched long term residents (Canadian-born individuals or pre-1985 immigrants). Each study focused on one factor associated with one of the three stages of immigration: pre-immigration (region of origin), peri-immigration (admission class), and post-immigration (area material deprivation).Methods: Population-based administrative data sources were linked to measure primary care visits, psychiatrist visits, and hospital use (i.e., emergency department visits or hospital admissions) for non-psychotic disorders by recent immigrants (i.e., within five years of arrival)in Ontario during 1993-2012. Results: Immigrants' service use patterns for non-psychotic mental health disorders differed from long term residents, with immigrants generally using less mental health care. In the pre-immigration study on world region of origin, immigrants from all regions used less psychiatry and hospital services than long term residents, while immigrants' use of primary care relative to long term residents varied by region of origin.In the peri-immigration study on admission class, male refugees were more likely to use primary care than long term residents. No admission class of immigrants had greater use of psychiatry or hospital care than comparators. In the post-immigration study on material deprivation, immigrants were over-represented in deprived areas. While residence in more deprived areas was associated with greater use of primary and hospital mental health care, immigrants exhibited smaller increases in use than long term residents.Discussion: Given rising immigration levels globally and Ontario, reviews of existing practices and policies are necessary to better understand immigrants' lower use of mental health service use and different patterns of use than long term residents.

Advisor: Glazier, Richard H
Effects of Flashing on Characteristics of Splashplate Nozzle Sprays

Black liquor, the byproduct of karf process to produce pulp, is injected into kraft recovery boiler to recover its energy and valuable chemicals. The temperature of the black liquor is increased to reduce its viscosity. Above the boiling point, a part of water content of black liquor starts to evaporate and creates a two-phase spray. This is a common phenomenon in the sprays that work at high temperatures, called "flashing". Flashing can change spray pattern, breakup mechanism, droplets size, droplets velocity and mass distribution. In this thesis the objectives are first, to predict the conditions at which flashing can occur, and second, to predict the effects of flashing on spray characteristics such as droplets size, droplet velocity and spray pattern. Water was used to simulate black liquor and a small scale nozzle was used to inject it into a spray chamber. The experiments were performed below and above flashing point. Spray patterns and internal flow regimes were studied using hundreds of images using DSLR and high-speed cameras. A particle sizing technique in imaging was used to measure the droplets size. Phase Doppler Anemometry was another technique for droplets size measurement and all of the measurements in all of the conditions were repeated using this method.Then another set of images, which were taken from black liquor sprays in a real size system, were analyzed. These images were taken during a separate experimental work in Helsinki, Finland. Spray patterns were categorized based on nondimensional values and a correlation was proposed to predict the conditions at which flashing occurs. New image analysis techniques were developed to obtain all the information available in the images about the particles size and velocity. Then the results of droplet size measurement from water and black liquor were combined and a correlation that can predict the average droplet size was obtained. Using the findings of this study, the operators of the boiler can adjust the temperature and mass flow rate of the black liquor to avoid flashing conditions or make flashing occur in case it is required, without suffering from damages due to unknown circumstances.

Keywords: Bubble
Droplet
Flashing
Phase Change
Sprays
Advisor: Ashgriz, Nasser
Tran, Honghi
Estrogen Receptor-related Receptor Gamma (ERRg) is a Regulator of Skeletogenesis

Sex steroids, such as Estrogen, play important roles in physiological and pathological processes, including bone growth and bone homeostasis. Estrogen's effects are mediated through its receptors, Estrogen receptor alpha and beta (ER and ER). Despite its importance, loss of expression of ERs does not result in severe skeletal effects, suggesting that other factors are involved in the Estrogen pathway(s). Estrogen receptor related receptors (ERRs) are a family of orphan nuclear receptors, i.e., with no known natural ligands, comprising ERRα, ERRβ, and ERRγ. While ERR has been shown to be involved in various aspects of skeletogenesis, there is very little know about the potential role of ERR. To address this question, I used gain-of-function and loss-of-function approaches in mice. In the gain-of-function model with cartilage-specific ERR-overexpression, the size of the craniofacial, axial and appendicular skeletons was reduced compared to that in wild type (WT) mice. Histological analysis revealed a reduction in the length of the transgenic versus WT growth plate, attributable to a reduced proliferative zone accompanied by a decrease in the number of Ki67-positive proliferating cells, with no significant change in apoptosis. Quantification of expression of putative target genes suggested that ERRγ negatively regulates chondrocyte proliferation and positively regulates matrix synthesis to coordinate growth plate height and organization. In an ERRγ global knockout mouse line, I observed no gross morphological anomalies or difference in skeletal length in newborn mice, but by 8 weeks of age ERRγ +/- male but not female mice exhibited increased trabecular bone, which was further increased by 14 weeks. Histomorphometric and serum biochemistry data indicated that the trabecular bone increase was due to an increase in bone formation, with no apparent change in bone resorption. Analysis of ERRγ +/- versus ERRγ +/+ bone marrow stromal cell cultures indicated that ERRγ negatively regulates osteoblast differentiation and matrix mineralization but not mesenchymal precursor number. These data, together with results from co-immunoprecipitation and Runx2 antisense oligonucleotide treatment experiments in vitro, indicated that ERRγ is not required for skeletal development but is a sex-dependent negative regulator of postnatal bone formation, acting in a RUNX2- and apparently differentiation stage-dependent manner. I conclude that ERRγ plays negative regulatory roles in both cartilage and bone in postnatal mice and may be an important new therapeutic target in skeletal diseases and conditions.

Advisor: Aubin, Jane E
Structural Abnormalities and Treatment-related Plasticity in Classical Trigeminal Neuralgia

Classical trigeminal neuralgia (TN) is a unique neuropathic pain disorder characterized by highly intense electric shock-like attacks of unilateral facial pain. While TN is commonly associated with neurovascular compression of the trigeminal nerve at the root entry zone (REZ) its pathophysiology is not well understood. In conjunction with trigeminal nerve abnormalities, central gray matter and white matter (GM, WM) structure may be affected and/or contribute to the maintenance of TN. Surgical treatment for TN may produce analgesia by effectively normalizing these structural abnormalities. The main aim of this thesis is to determine if there are structural neural abnormalities in patients with TN and whether effective neurosurgical treatment can reverse these abnormalities. The specific aims were to determine: 1) if patients with TN have brain GM abnormalities; 2) if patients with TN have trigeminal nerve and/or brain WM abnormalities based on multiple DTI-derived metrics; 3) if effective neurosurgical treatment for TN is associated with a reversal of the trigeminal REZ and cortical and subcortical GM abnormalities that we report in studies 1 and 2 of this thesis. In groups of TN patients with right-sided pain and healthy age- and sex-matched controls, magnetic resonance imaging revealed that patients had: 1) increased GM in the sensory thalamus, amygdala, periaqueductal gray, basal ganglia, contralateral primary somatosensory cortex, and frontal pole and less GM in the pregenual anterior cingulate cortex, insula, and orbitofrontal cortex; 2) abnormalities in the trigeminal REZ and cerebral WM tracts including the corpus callosum, cingulum, corona radiata, and superior longitudinal fasciculus; and 3) a reversal ventral anterior insula and trigeminal REZ abnormalities following effective treatment, with the degree of REZ normalization correlating with pain relief. Taken together, this thesis demonstrates for the first time both trigeminal nerve and brain abnormalities in patients with TN, and the impact of effective treatment on these abnormalities.

Keywords: brain plasticity
MRI
neuroimaging
pain
trigeminal nerve
trigeminal neuralgia
Advisor: Davis, Karen D.
Hodaie, Mojgan
Investigation of the Interfaces between Cu(111)-based Electrodes and Water Using Density Functional Theory

This thesis presents a fundamental study of the interface between Cu(111)-based electrodes and water. Density functional theory is used to investigate the interaction between water and Cu(111) both in the absence and presence of an external electric field. To analyze the water-electrode interaction in depth, a monomeric adsorption of water is studied and compared with other similar types of molecules. The orientation of the adsorbed molecules is found to be influenced by the energy gap between the Fermi level of Cu(111) and the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the molecules. A simple relationship is observed where a stronger dipole moment of the molecule and a lower adsorption energy lead to an interface which responds more sensitively to the external electric field. The dipole moment is a more critical parameter.The behaviour of a water overlayer is then investigated on Cu(111). A differential capacitance of the Cu(111)/water interface remains constant when the molecular movements of water is ignored. The change in the orientations of the water molecules causes the differential capacitance of the interface to be potential dependent. A sharp increase in the differential capacitance is found when the water layer undergoes a structural transition. A new method, namely a "constant field" method is devised to determine the potential of the electrode at a given external electric field.The impact of coating Cu(111) with a layer of graphene is also studied. A quantum capacitance, an intrinsic capacitive property of graphene, is found to influence the differential capacitance of the graphene-coated Cu(111). However, it was found that the electronic interaction between graphene and Cu(111) alters the differential capacitance of the interface at certain electrode potentials. The change in the differential capacitance cannot be predicted by the standard modelling approaches and thus, ab initio modelling of the electrified interface is necessary. The water layer does not heavily influence the interaction between graphene and Cu(111), which agrees with the conventional understanding that graphene-coating suppresses the oxidation of the Cu surfaces.

Keywords: Density Functional Theory
Electrochemical Energy Storage
First principles
Interface
Modeling
Advisor: Dawson, Francis P
Lian, Keryn K
Sleep Disturbance in Family Caregivers of Children who Depend on Medical Technology Compared to Family Caregivers of Healthy Children: The CARE to SLEEP Study

Background/Rationale: Society relies on family caregivers of children who depend on medical technology (e.g., home ventilation) to provide highly skilled and vigilant care up to 24 hours per day. Few studies exist that have measured sleep in family caregivers, and those that do have relied entirely on subjective measures. These data suggest that sleep disruption places family caregivers at risk for poor health and related outcomes that may impair their daytime function and long-term capacity for caregiving. Objectives/Research Questions: The primary aim of this study was to compare sleep and related outcomes in family caregivers of children who depend on medical technology to outcomes in family caregivers of healthy children.Methods: In a prospective cohort study (balanced per child's age), 42 family caregivers of children who depend on medical technology from a tertiary-level paediatric hospital and 43 controls from community-based paediatric clinics were recruited. Actigraphy was used for 6 days and 7 nights, and the Pittsburgh Sleep Quality Index (PSQI) was applied to collect sleep data. At home visits, sleep diaries were collected and measures of depression (CES-D), daytime sleepiness (ESS), fatigue (MAF), quality of life (SF-12TM), sleep hygiene (SHI), and child's sleep habits (CSHQ) were administered.Results: Family caregivers of children who depend on medical technology achieved 40 minutes less sleep per night (6.56 [1.4h] vs. 7.21 [0.6], p = .02), had more nocturnal awakenings (8.00 [3.9] vs.6.01 [3.7], p = .02), and had more sleep deprived (

Keywords: caregiver
chronic illness
family centred care
paediatrics
sleep
technology dependent
Advisor: Stremler, Robyn
Effect of Mobility on the Sensing and Communication Performance of Mobile Sensor Networks

We study the effect of mobility on the sensing and communication performance of a sensor network with mobile nodes. Communicating the sensed data clearly necessitates that the sensor node is able to connect to adjacent (sensor or sink) nodes to be able to exchange its information. Same node to node links can also be used in the sensing phase if a cooperative sensing scheme is in place. Assuming that the phenomenon being sensed generates a sparse and spatially correlated signal across the sensors, the theory of distributed compressive sensing suggests that cooperative sensing can facilitate the sensing process. We study the effect of mobility on the probability that a sensor node can connect to its neighboring nodes either to communicate its sensed data or to initiate a cooperative sensing procedure. We show that, by increasing the probability of such connections, mobility enhances both communication and sensing performance of mobile sensor networks.We first study how mobility of the nodes affects the communication performance of a mobile network. Based on a Wiener process mobility model, and in a network with mobile sensor and sink nodes, we study a repetition based approach for sensor node to sink node communication, where sensor nodes attempt communicating their sensed data with sink nodes repeatedly between two sensing instants. Using a stochastic framework, we prove that the average number of successful communications is an increasing function of the sensor node's mobility.Then, we study the sensing performance of the above network based on a cooperative sensing scheme. In this scheme, sensors share their samples and perform the sensing cooperatively, reducing the required number of samples per sensor node. The reduction in the number of samples each sensor needs to obtain, namely the sensing gain, depends on the level of correlation between such samples. Adopting a joint sparsity model for the correlation between the samples of the sparse signal, we show that the mobility of the sensor nodes can increase the chances of higher correlation between the samples, leading to a reduction in the number of requires samples.

Keywords: cooperative sensing
mobility diversity
mobility model
mobility sensing gain
sensor network
Advisor: Valaee, Shahrokh
Shahbazpanahi, Shahram
System for Interpretation of Personal Genomes

Genomics is undergoing a revolution sparked by higher throughput and cost effective DNA sequencing technologies. Sequencing has become a ubiquitous tool with varied inputs, scopes, techniques, technologies, and purposes. There is potential for the development of software systems that assist in translating raw sequence data into actionable information that helps improve disease assessment, detection, and treatment so that individuals who are or may be affected by genetic conditions are treated with an unprecedented level of precision and predictiveness. This new kind of medicine informed by personal genomic interpretation promises to have immense medical and economic benefits. Despite the capacity of new sequencing technologies to generate huge volumes of raw sequence data, it remains a substantial informatics challenge to efficiently analyze it. HTS technologies produce data at a rate that exceeds Moore's Law, creating enormous technical and usability issues. Freely available tools that are both powerful enough to be efficient and user-friendly enough to be used by genomic researchers without informatics expertise are scarce. Notwithstanding a few exceptions, users are often forced to choose between powerful, specialized software that needs to be run on the command-line or alternatives that are less specialized but are graphical and user-friendly. This thesis presents two software platforms that combine techniques from various domains of computer science, most notably data structures, databases, algorithm design, data visualization, user interface design, and user experience design, that together form a highly integrated system for interpretation of personal genomes that is both powerful and easy to use.

Keywords: big data
databases
genomics
high throughput sequencing
user interfaces
visualization
Advisor: Brudno, Michael
Electrophilic Fluorophosphonium Cations - The Transition from Boron to Phosphorus Lewis Acids in Frustrated Lewis Pair Chemistry

Catalytic transformations are of utmost importance for the synthesis of goods and materials. Transition metal systems have traditionally been employed for catalytic processes, however this notion has begun to change with the renaissance in metal-free catalysts. One subset of metal-free catalysis is frustrated Lewis pairs (FLPs). These are combinations of Lewis acids and Lewis bases that are precluded from generating classical adducts due to steric encumbrance. This thesis expands the scope of FLP reactivity by investigating the chemistry with novel Lewis bases, acids and substrates. Sterically unencumbered amines form Lewis acid base adducts with B(C6F5)3. These amines were encapsulated into a [2]rotaxane in order to impart steric protection without covalent modifications. These combinations were shown to activate H2 in an FLP manner and led to the discovery of an oxygen/boron hydrogenation catalyst. Phosphorus/boron FLPs were reacted with a variety of fluoroalkanes resulting in the activation of the C-F bond. From this it was shown that B(C6F5)3 can act as a competent hydrodefluorination catalyst for fluoroalkanes. The reactions of P/B FLP systems with XeF2 were also explored, resulting in the formation of fluorophosphonium fluoroborate salts. This led to the discovery of highly electrophilic fluorophosphonium cations. Organophosphorus compounds are best known for their roles as Lewis bases. Considerably less attention has been paid to Lewis acidic phosphonium cations. The reactivity of these EPCs is described herein. They have found applications in CO2 sequestration, catalytic C-F bond activation, hydrosilylation, dehydrocoupling and transfer hydrogenation reactions. Finally, they have shown promise in FLP chemistry, with preliminary results indicating they are capable of acting as a Lewis acid for H2 activation.

Advisor: Stephan, Douglas W
Low Dose Computed Tomography Reconstruction Methods

This study examines potential methods of achieving a reduction in X-ray radiation dose of Computer Tomography (CT) without significantly degrading the quality of the CT images. Assuming that the effective X-ray dose in CT is proportional to the product of the exposure area, the number of projections and the dose for each projection, four approaches are proposed to lower the radiation dose. Each of the proposed approaches controls one of these factors. Increasing the slice thickness increases the number of detected X-ray photons, thereby reducing the image noise. However, it also reduces the detectability and measurement accuracy of the small structures. An optimum slice thickness/overlap for low dose thoracic-CT images is proposed to compromise between the detectability and characterization accuracy of small pulmonary nodules.Compressed Sensing (CS) based CT reconstruction methods have shown significant potential for low dose CT imaging by reducing the number of projections. The connection between the statistical iterative CT reconstruction and compressed sensing is explored, based on maximum a posteriori formulation of CT reconstruction. It is shown that this formulation can be transformed into a weighted CS problem, the weights of which are direct consequences of the geometry and the CT statistics. A computationally efficient solution is proposed, enabling lower dose CT scans, while substantially reducing the computational load in comparison to conventional CS-based CT reconstruction methods.An iterative denoising algorithm is proposed to improve the CNR of the low dose CT images. To achieve this goal, a noise confidence region evaluation algorithm is proposed to adaptively update the regularization parameters, by validating the statistical properties of the denoised images at the end of each iteration. The algorithm stops when the statistical properties of the denoising residual resemble those of the considered noise. Finally, an innovative combination of a newly developed accelerated wavelet inverse Radon transform and non-convex CS formulation is proposed to recover the wavelet subbands of CT images from a reduced number of locally scanned projections. The proposed method reduces the radiation dose by simultaneous reduction of the number of projections and the area of exposure.

Keywords: Compressed Sensing
Image Reconstruction
X-ray Computed Tomography
Advisor: Cobbold, Richard S.C.
Paul, Narinder S