VictorJuiz/thesis huggingface dataset:
The Role of the Dopamine D, Receptors in Cue-induced Reinstatement of Nicotine-seeking Behaviour
Keywords: dopamine D3 receptors
addiction
brain
drug discovery
motivation

Dopamine D3 receptors (DRD3) are implicated in relapse to drugs. The current study investigated the role of DRD3 in cue-induced reinstatement of nicotine-seeking in rats. Rats were trained to lever-press for intravenous infusions of nicotine, associated with the illumination of a cue-light, under a fixed-ratio schedule of reinforcement. Following extinction of the behaviour, where lever pressing had no consequences, reinstatement testing was performed by reintroduction of the cues after systemic or local administration (into discrete brain areas) of the DRD3 selective antagonist SB277011-A. Systemic antagonism of DRD3 significantly attenuated cue-induced reinstatement of nicotine-seeking. The same effect was observed upon infusions of SB277011-A into the basolateral amygdala or the lateral habenula, but not the nucleus accumbens. The current findings implicate DRD3 in cue-induced reinstatement of nicotine, delineate some of the neural substrates underlying this role and support a potential for using selective DRD3 antagonists for the prevention of relapse to smoking.
Light Localization in Coupled Optical Waveguides
Keywords: Waveguide array
Bloch Oscillation
Dynamic Localization
Quasi-Bloch
Curved waveguide

This thesis analyzes different light localization phenomena in waveguide arrays. We report on the observation of quasi-Bloch oscillations, a new type of dynamic localization in the spatial evolution of light in curved, coupled optical waveguides. The delocalization and final relocalization of an optical beam in a waveguide array is shown by spatially resolving the optical intensity at various propagation distances. Through comparison to different structures, quasi-Bloch oscillations are shown to be robust beyond the nearest-neighbor tight-binding approximation.
Learning Deficits after Experimental Subarachnoid Hemorrhage (SAH)
Keywords: SAH
Learning
Stroke
Memory
Biomedical
Neuroscience

Survivors of subarachnoid hemorrhage (SAH) often have learning and memory deficits. This study tested the hypothesis that SAH in rats is associated with similar deficits and that they are due to neuronal injury in the hippocampus. SAH was induced in rats. Behaviour was investigated in the Morris water maze and brain injury by microscopy. Rats with SAH had deficits in spatial learning and working memory and had significantly more fluoro-Jade- and TUNEL-positive neurons in the hippocampus, cerebral cortex and cerebellum. Microthromboemboli in microvessels were more frequent in brains of rats with SAH and deficits there was vasospasm of the anterior and middle cerebral arteries. The amount of cell death in the hippocampus did not appear to be sufficient to cause the observed in the Morris water maze. This suggests that other factors such as dysfunction of neurotransmission or other pathology in hippocampal pathways might contribute to the impairment.
The Effect of Temperature on the Chronic Hypoxia-induced Changes to pH/CO2-sensitive Fictive Breathing in the Cane Toad (Bufo marinus)
Keywords: Control of Breathing
Temperature
Hypoxia
Amphibian
in vitro brainstem-spinal cord

This study examined the effects of temperature and chronic hypoxia (CH) on pH/CO2- sensitive fictive breathing, and central pH/CO2 chemosensitivity, in cane toads (Bufo marinus). Toads were exposed to CH (10% or 15% O2) or control conditions (21% O2) for 10 days at either room temperature (controls), 10°C or 30°C following which in vitro brainstem-spinal cord preparations were used to examine central pH/CO2-sensitive fictive breathing (i.e., motor output from respiratory nerves which is the neural correlate of breathing). A reduction in artificial cerebral spinal fluid (aCSF) pH increased fictive breathing frequency (fR) and total fictive ventilation (TFV). Cold temperature reduced and hot temperature increased fR and TFV under control conditions. CH attenuated fictive breathing independently of temperature. Additional experiments in which the aCSF temperature was varied indicate that the effects of temperature acclimation result from neural plastic changes within respiratory control centres in the brain.
Metabolic Modeling of Spatial Heterogeneity of Biofilms in Microbial Fuel Cells
Keywords: Microbial fuel cells
Metabolic Modeling

Microbial fuel cells (MFCs) are alternative energy resources that generate electricity from organic matter, where microorganisms such as the Geobacter species oxidize organic waste and transfer electrons to an electrode. Mathematical models are used to study biofilm processes, in hopes of developing MFCs into commercial applications. Existing biofilm models are based on Nernst-Monod type expressions, and are restricted to studying extracellular electrochemical/microbiological components, separated from the metabolic behavior of microorganisms. In this thesis, a model was developed combining extracellular biofilm conditions, with the intracellular metabolic fluxes of microorganisms under spatial heterogeneities (electron donor/acceptor levels) across the biofilm. This model predicts biofilm processes under varying extracellular conditions (presence/absence of NH4+, shear stress in continuous mode MFCs), and intracellular conditions (ATP maintenance fluxes); and also provides a preliminary evaluation of the pH changes across the biofilm. A sensitivity analysis based on the cell density and the biofilm conductivity was also conducted.
The Influence of Dietary Factors on Reproduction in the Fruit Fly, Drosophila melanogaster
Keywords: drosophila melanogaster
behaviour
food
reproduction

Food and nutrition are important for energy balance, reproduction and maintenance of health in all species. Drosophila melanogaster feed on yeast and sugar and food availability affects reproduction. In this thesis, I show that mating frequency and fertility are affected by the composition of food in two D. melanogaster wild-type strains, Canton-S and Oregon-R. Canton-S flies mate multiple times in the presence of yeast and sugar, while Oregon-R only remate in the presence of yeast. However, Oregon-R flies have higher fertility counts on all food types compared to Canton-S. These effects of food do not appear to depend on smell or taste, because both chemosensory mutants and artificial sweeteners tested fail to block the effects of food on reproduction. Moreover, Canton-S, but not Oregon-R flies show an interaction between food and group size. I conclude that genetic differences, social context and nutrition interact to regulate reproduction in flies.
Analysis of Sequence and Function of Drosophila Microvillus Cadherins, Cad74A, Cad87A, and Cad88C
Keywords: Drosophila
Microvillus
Cadherins
Oogenesis

Microvilli are actin-based protrusions at the apical surface of epithelial cells and have diverse functions. My bioinformatic analysis suggests that human Cadherin 23, which is critical for normal microvillus development, has three paralogous homologues in Drosophila, Cad74A, Cad87A, and Cad88C. All three fly cadherins are present in follicle cell microvilli in late stages of oogenesis. The combined loss of Cad74A, Cad87A, and Cad88C did not produce any obvious defects in follicle cell microvilli or egg morphology. However, in a Cad74A Cad88C double mutant, Cad87A is strongly reduced at the apical surface of follicle cells. Furthermore, females overexpressing Cad74A produced abnormal eggs. This phenotype was rescued by increasing or reducing Cad87A expression. Together, my data suggest genetic interactions between the three cadherins, and that Cad74A and Cad87A may be involved in eggshell formation.
Accurate and Efficient Evaluation of the Second Virial Coefficient Using Practical Intermolecular Potentials for Gases
Keywords: Second Virial Coefficient
Intermolecular Potential Energy Models
Polynomial Interpolation
Quantum Correction

The virial equation of state p = ρRT[ 1 + B(T) ρ + C(T) ρ2 + · · ·] for high pressure and density gases is used for computing chemical equilibrium properties and mixture compositions of strong shock and detonation waves. The second and third temperature-dependent virial coefficients B(T) and C(T) are included in tabular form in computer codes, and they are evaluated by polynomial interpolation. A very accurate numerical integration method is presented for computing B(T) and its derivatives for tables, and a sophisticated method is introduced for interpolating B(T) more accurately and efficiently than previously possible. Tabulated B(T) values are non-uniformly distributed using an adaptive grid, to minimize the size and storage of the tables and to control the maximum relative error of interpolated values. The methods introduced for evaluating B(T) apply equally well to the intermolecular potentials of Lennard-Jones in 1924, Buckingham and Corner in 1947, and Rice and Hirschfelder in 1954.
Reducing Pain in Four- to Six-month Old Infants Undergoing Immunization using a Multi-modal Approach
Keywords: pain
infants
immunization
vaccine
procedural pain
tactile stimulation
sucrose
distraction
randomized controlled trial
blinded
injection pain
immunization pain

Background: Infant immunization pain is not currently well managed despite effective strategies. Objective: To determine the effectiveness of tactile stimulation when added to a combination of pain-reducing interventions in infants undergoing immunization. Methods: Healthy infants aged 4-6 months undergoing immunization in primary care were randomized to tactile stimulation or usual care. All infants also received pain-relieving interventions. A validated measure of acute pain in infants, the Modified Behavioral Pain Scale (MBPS), was the primary outcome. Results: Altogether, 120 infants participated. Characteristics did not differ (p > 0.05) between those allocated to tactile stimulation and usual care groups. Mean MBPS pain scores did not differ between groups: 8.2 (1.1) vs. 8.0 (1.3); p = 0.57, respectively. Conclusions: Parent-led tactile stimulation did not improve pain relief in infants when added to other interventions. Parental attention could have been focused on tactile stimulation, preventing parents from performing appropriate soothing activities. Additional investigation of the effectiveness of clinician-led tactile stimulation is recommended.
Becoming a Muslim Woman: Conversations on Conversions
Keywords: conversion
Muslim

This thesis deals with the conversion stories of five female converts to Islam; considering the expectations my interlocutors have faced, the pressures to tell a certain type of narrative, the formation of their practice and the stories they choose to narrate. The concept of an ‘epiphany’ narrative, a story of inspiration and divine intervention, will be discussed and placed into tension with ‘rupture’ narratives; the stories my interlocutors tell in order to ‘make sense’ of their conversions.
Climate-induced Tree Migration in Southern Ontario: Pathways and Source Populations
Keywords: Climate change
Tree migration
GIS

Under the current rapid climate change, trees are of critical interest because of diverse ecosystem services that they provide. Although increasing landscape connectivity is though to be crucial in order to maximize their migration capabilities, there are few studies indicating where exactly such increases might best take place. To understand the impact of fragmentation on species climate-change induced migrations and source populations, I calculated migration pathways and source populations under six climate change scenarios in southern Ontario where >70% of forest has been lost through human-use. The results showed that although forest fragmentation increased species required migration rates, the most important migration corridors and source populations were quite similar across all migration models and were concentrated in exiting forest corridors and extensively forested areas, including northeast of Lake Ontario, the Niagara Escarpment, and the Oak Ridges Moraine.
Fabrication of Photonic Crystal Optofluidic Devices for Electrochromatography and Spectroscopy on a Chip
Keywords: Microfluidics
Photonic Crystals
Laser Processing

Femtosecond laser processes were optimized for nonlinear interactions with optical materials to develop a novel biophotonic lab-on-a-chip device that integrates laser-formed waveguides, microfluidic channels and photonic crystals (PCs). Such integration seeks the novel demonstration of dual PC functionalities: (1) efficient chromatographic separation and filtration of analytes through a porous PC embedded inside a microfluidic channel and (2) optofluidic spectroscopy through embedded waveguides that probe PC stop band shifts as varying analyte concentrations flow and separate. The building blocks for such integration were demonstrated through the accelerated analyte flow rates measured through the embedded porous PC and the optical characterization of a PC’s stop band via integrated waveguides. Together, these laboratory results give promise for achieving simultaneous chromatographic and spectroscopic capabilities in a single PC optofluidic device. Future improvements in the laser process and possible new research directions are also offered.
Implementation of Electronic Medical Records and Preventive Services: A Mixed Methods Study
Keywords: Electronic health records
Preventive health services
Quality of health care
Primary health care

The implementation of Electronic Medical Records (EMRs) may lead to improved quality of primary health care. To investigate this, we conducted a mixed methods study of eighteen Toronto family physicians who implemented EMRs in 2006 and nine comparison family physicians who continued to use paper records. We used a controlled before-after design and two focus groups. We examined five preventive services with Pay for Performance incentives: Pap smears, screening mammograms, fecal occult blood testing, influenza vaccinations and childhood vaccinations. There was no difference between the two groups: after adjustment, combined preventive services for the EMR group increased by 0.7% less than for the non-EMR group (p=0.55, 95% CI -2.8, 3.9). Physicians felt that EMR implementation was challenging.
A Detailed Genomic and Transcriptomic Analysis of Paediatric Undifferentiate Sarcomas
Keywords: Sarcoma
Molecular Biology

Paediatric undifferentiated soft tissue sarcomas (USTSs) are a diagnostically challenging group of neoplasms. We hypothesized that USTSs contain distinct subgroups that can be identified based on their morphology, genomic aberrations and expression profiles. We sought to characterize genomic aberrations within primitive round cell (PRC) sarcomas which may underlie aberrant expression patterns. Using molecular and cytogenetic analyses, we identified 5 of 18 CIC-DUX4-positive PRC sarcomas. The consistent involvement of the CIC-DUX4 fusion in a subset of PRC sarcomas suggests a central role for the fusion transcript in such tumours. These analyses also identified a cohort of CIC-DUX4-negative USTSs with no established genetic markers. We performed integrative copy number and expression profiling, and identified significant genomic and transcriptomic changes. We propose that these genes are involved in biological pathways that are important to the initiation and progression of undifferentiated sarcoma, and may provide novel insights into the biological events responsible for sarcomagenesis.
Modeling of an Underground Mine Backfill Barricade
Keywords: Underground fill fence
backfill
Augustus-2
VecTor4

In this thesis finite element analyses were performed to investigate the behavior of fill fences installed in underground mines to retain Cemented Paste Backfill (CPB) pressure. For this purpose, two fill fences installed and tested in the Cayeli mine in Turkey were modeled using a 2-D nonlinear finite element analysis program, Augustus-2, and a 3-D nonlinear finite element analysis program VecTor4, and the results were compared with measured field data. Different models were employed representing the material properties, boundary conditions, reinforcement ratio, and geometric properties, and it was found that boundary conditions (stiffness of surrounding rocks) has the highest influence on the pressure capacity of the fence among the other factors. The accuracy of the Augustus-2 program was investigated by modeling and comparing the analytical response with test results of 12 axially restrained beams tested by Su et al. (2009).
Oxidation of Organic Species in Ice
Keywords: ice chemisty
dicarboxylic acids
humic acids
snow photochemistry
OH radical
Arctic chemistry
photochemistry
organic films

Oxidation of organic species, in particular dicarboxylic and humic acids, was investigated in ice. Products were analyzed by Proton Transfer Reaction Mass Spectrometry, ion and gas chromatography, and a Total Organic Carbon analyzer. Photolysis of succinic acid with H2O2, an OH precursor, produced malonic acid and malic acid, illustrating that diacids are subject to photochemical degradation in ice. First-order decay rate constants were an order of magnitude higher at room temperature (~23 °C) than in ice (-20 °C). A smaller difference was observed for malonic acid, a more soluble diacid, suggesting that partial segregation of H2O2 and succinic acid during freezing played an important role in the kinetics. VOCs, likely to be aldehydes and ketones, were produced from ice containing humic acid through heterogeneous ozonolysis and photooxidation which was enhanced by NO3-, an OH precursor. VOCs also formed from ice made from deionized water, likely through oxidation of organic contaminants.
111In-labeled Nimotuzumab Modified with Nuclear Localization Sequences (NLS): An Auger Electron-emitting Radiotherapeutic Agent for EGFR-overexpressing and Trastuzumab-resistant Breast Cancer
Keywords: Herceptin resistant breast cancer
Auger eletron radiotherapy
Nimotuzumab (mAb of EGFR)
Indium-111

Objective: The cytotoxic property of anti-EGFR-1 monoclonal-antibody nimotuzumab modified with nuclear localization sequence and radiolabeled with 111In was evaluated in trastuzumab-resistant breast cancer cells. Methods: 111In-nimotuzumab-NLS was constructed and its immunoreactivity was determined. Cellular and nuclear uptake was evaluated by cell fractionation. Finally, the cytotoxicity of conjugates (111In-nimotuzumab/111In-nimotuzumab-NLS) was studied by clonogenic assays. Results: The immunoreactivity of 111In-nimotuzumab-NLS was conserved. 111In-nimotuzumab-NLS exhibited 2-fold higher nuclear translocation as compared to 111In-nimotuzumab in MDA-MB-468 cells. Nuclear importation of 111In-nimotuzumab-NLS in MDA-MB-468 cells was 4-fold and 6-fold higher than moderate and low EGFR expressing cell lines, respectively. Clonogenic survival (CS) for MDA-MB-468 cells showed 111In-nimotuzumab-NLS to be 10-folds and 60-folds more potent than 111In-nimotuzumab and nimotuzumab, respectively. Moderate killing for TrR1 and MDA-MB-231 was observed. 111In-hEGF showed significantly higher cytotoxicity and 2-fold higher γ-H2AX foci integrated density/nuclear-area as compared to 111In-nimotuzumab-NLS. Preserved selectivity of 111In-nimotuzumab-NLS makes it an excellent drug for treating cancers.
Neuroanatomical Correlates of Depressive Symptoms Following Acute Ischemic Stroke
Keywords: stroke
depression
neuroimaging
CT

This study investigated the hypothesis that severity of depressive symptoms following acute ischemic stroke is associated with degree of tissue infarction and severity of white matter changes (WMCs). It employed a novel quantitative region-based approach considering both infarction and WMCs. Of 54 ischemic stroke patients recruited, 50 (72.3 ± 12.8 years, 52.0% male) had useable CT scans. The typical patient was recruited within 3 weeks of their stroke (19.7 ± 31.0 days), exhibited minor cognitive impairment (MMSE score 25.8 ± 4.6), and had mild to moderate stroke severity (NIHSS score 6.5 ± 5.4). 28.0% of patients screened positive for clinical depression with a CES-D score ≥16. While neither degree of infarction nor severity of WMCs (ARWMC score) in the 12 brain regions correlated with depressive symptoms (CES-D score), stroke severity was a significant predictor of depressive symptoms. This stressor, related to physical disability, was a predominant predictor over lesion characteristics.
Attitude Determination and Control Hardware Development for Small Satellites
Keywords: Attitude Determination and Control Hardware Development for Small Satellites

The development of a small spacecraft attitude determination and control subsystem is described. This subsystem is part of The Space Flight Laboratory's Generic Nanosatellite Bus. With a 20cm3 body, the bus has an attitude determination and control subsystem capable of full three-axis stabilization and control enabling more advanced missions previously only possible with bulkier and more power-consuming attitude control hardware. Specific contributions to the Space Flight Lab's attitude control hardware are emphasised. Particularly, the full development of a 32g three-axis nanosatellite rate sensing unit is described. This includes embedded software development, skew calibration, hardware modeling and qualification testing for the unit. Development work on a three-axis boom-mounted magnetometer is also detailed. A full hardware design is also described for a new microsatellite-sized rate sensor. Larger and more powerful than the nanosatellite rate sensors, the design ensures a low noise, low drift architecture to improve attitude determination on future microsatellite missions.
A Phenomic Assessment of Yeast DNA Damage Foci using Synthetic Genetic Array Analysis and High-content Screening
Keywords: Budding yeast
Genomics
Synthetic genetic array analysis
High-content screening
DNA damage foci
DNA repair
Rad52

Aberrant DNA synthesis and maintenance have been implicated in numerous human diseases. I describe here a novel strategy for systematically identifying budding yeast mutants with elevated levels of DNA damage foci, which represent hubs of DNA damage and repair. A previous study manually scored foci in single mutants but was limited in its ability to survey many conditions in large populations. I developed an automated and statistically robust method for identifying aberrant foci phenotypes by combining synthetic genetic array (SGA) and high-content screening (HCS) methodology. Using this approach, I scored thousands of essential and non-essential gene mutants subjected to environmental and genetic perturbations, including the DNA damaging agent, phleomycin, and deletions of DNA repair genes, SGS1 and YKU80. Collectively, I identified a functionally enriched set of 367 mutants that had increased frequencies of DNA damage foci and established SGA-HCS as a powerful tool for investigating the yeast DNA damage response.
On the Use of Double Auctions in Resource Allocation Problems in Large-scale Distributed Systems
Keywords: double auction
resource allocation
large-scale distributed systems

In this thesis, we explore the use of double auction markets as a general approach to tackle resource allocation problems in large-scale distributed systems, which are traditionally solved using optimization techniques. Prevalently adopted in real-world markets, double auctions have the power of arbitrating mappings between participating players and trading commodities in a decentralized fashion, with every player trying to maximize her own utility selfishly. Through the design of prefetching strategies in peer-assisted video-on-demand systems, we show how the problem of minimizing server bandwidth costs by reallocating media contents can be solved by double auction markets gracefully. However, not every resource allocation problem satisfies requirements of double auctions. We illustrate the limitation of double auctions with an example of virtual machine migration in container-based datacenters, which is then modeled into a Nash bargaining game and solved by a Nash bargaining solution.