VictorJuiz/thesis huggingface dataset:
Investigating the Influence of D4 Receptor Modulation on Alcohol Addiction-Relevant Behaviours

The recent development of selective dopamine D4 receptor ligands has made it possible to further examine their effects on addiction-relevant behaviours. This study investigated the effects of D4 receptor modulation, using the selective antagonist L-745,870 and agonist PD 168,077, on alcohol self-administration and reinstatement induced either by cue or stress. Although activation of the D4 receptor was ineffective, inactivation attenuated alcohol self-administration without affecting food self-administration. Initial analyses of reinstatement experiments found no significant effects, but by distilling for robust responders, alcohol-seeking was reduced by D4 receptor inactivation under stress-induced reinstatement. The culmination of this work deepens existing lines of evidence that the D4 receptor is involved in addictive disorders, and suggests that D4 receptor blockade diminishes motivation for alcohol-taking without influencing natural food rewards. Furthermore, there appears to be a plausible effect of D4 receptor blockade interfering with stress- but not cue-induced alcohol-seeking.

Keywords: Alcohol
D4 Receptor
Dopamine
Advisor: Le Foll, Bernard
Shared Enemies and the Competitive Ability of Native Plants in Populations of an Invasive Plant (Cirsium arvense)

Shared enemies commonly mediate interactions between plant species. Here, I investigated how two guilds of enemies can indirectly affect native plant communities through interactions with an invading plant, Cirsium arvense (Canada thistle). First, I assessed how soil microbes in invaded areas can limit the establishment of native plant species. Microbes from invaded soils reduced germination or growth for three of the eight native plant species surveyed, but did not affect Cirsium, which suggests that soil microbial interactions may benefit Cirsium, potentially facilitating its invasion. Second, I assessed the influence of Cirsium invasion on damage by aboveground insect enemies. Based on plants' association with Cirsium, I observed inconsistent and very minor patterns in insect damage, which suggests that other ecosystem factors influence damaging insects more strongly than Cirsium invasion. Together, these results indicate that soil microbial enemies, but not aboveground insect enemies, may be influential in the invasion of Cirsium arvense.

Keywords: Cirsium
community
invasion
microbe
plant
soil
Advisor: Kotanen, Peter M
The Effect of Epigallocatechin-gallate on Inflammatory Protein Production of Odontoblast-like cells

Objective: To evaluate the effect of Epigallocatechin-gallate (EGCG) on the cell viability, cytokinome, and protein production of the MDPC-23 cell line with or without Streptococcus mutans (SM) stimulation, compared with Chlorhexidine diacetate (CHX). Methods: Part 1: Cytotoxicity of CHX and EGCG treatment; cytokine secretion was analyzed using a Cytokine 23-plex Assay. Part 2: Cytotoxicity of SM stimulation with CHX and EGCG treatment; protein production was measured using ELISA and LC-MS/MS. Results: At 24 and 48 hours, cell metabolic activity was stable at 2.5-20 µM (CHX) and 2.5-160 µM (EGCG), respectively. CHX 10 µM (stimulated or not with SM) increased IL-1β levels despite lowering total protein levels compared to control and EGCG at 10 µM with SM stimulation increased peroxiredoxin-1 abundance compared to control. Conclusion: Protein production varied between treatments, with EGCG being viable at higher concentrations than CHX. EGCG may have potential as a treatment in dental caries-related inflammation.

Advisor: Prakki, Anuradha
Multiple Mutualist Effects in an Ant-Plant-Bacteria System

Plants simultaneously partake in multiple mutualisms, and partner species that share a focal host are capable of indirectly affecting one another, potentially affecting the outcome of mutualisms. Context-dependence is thought to largely determine the nature of these multiple mutualist effects as well as focal host resource allocation in each partner. We factorially manipulated the ant "bodyguards" and nitrogen-fixing rhizobia that associate with the legume Chamaecrista fasiculata in a field experiment to determine how each mutualistic partner affected the other. Rhizobia treatment impacted the identity and abundance of ants. Both rhizobia treatment and ant treatment impacted plant survival. Additionally, ant and rhizobia treatment affected the weight of nodules housing rhizobia, but in a way that depended on plant size. Our results show that belowground mutualists can influence plant interactions with aboveground mutualists, and vice versa. This study highlights the importance of incorporating multiple mutualist effects in to our understanding of mutualisms.

Keywords: Ants
Ecology
Legume
Multiple Mutualist Effects
Mutualism
Rhizobia
Advisor: Frederickson, Megan E
Towards Practical Driver Cognitive Workload Monitoring via Electroencephalography

Monitoring of Driver Cognitive Workload is an active area of research and has gained traction in recent years. This study pertains towards the development of an Automated Driver Cognitive Workload Prediction System using the Electroencephalography modality. In this experiment, the driver cognitive workload has been modelled using a secondary n-back task. This study aims to answer the question if a consumer-grade 2-channel EEG modality can be used to discriminate between the granular cognitive workloads induced on the driver as it is measured by the n-back test. Statistical Learning Models are generated while taking into account the practical data-partitioning schemes as would be feasible in real world implementation. It is found that individual Beta and Gamma bands provide good discriminating performance while using a combined set of 32-features provides the best overall performance. Non-Linear Classifiers outperform the linear classifiers and dimensionality reduction techniques assist in producing practical prediction models.

Keywords: Cognitive Workload
Driving
eDREAM
EEG
Machine Learning
nBack
Advisor: Plataniotis, Konstantinos N
Hepatocyte Growth Factor-Preconditioned Neural Progenitor Cells Attenuate Astrocyte Reactivity and Promote Neurite Outgrowth

The astroglial scar is a defining hallmark of secondary pathology following central nervous system (CNS) injury that significantly obstructs neuroregeneration. Neural progenitor cell (NPC) therapies for repair and regeneration have demonstrated favourable outcomes not only via cell replacement, but trophic support. In an effort to strategically enhance this secretory potential, we utilized the regenerative aptitude of hepatocyte growth factor (HGF) as a cellular preconditioning agent and assessed the capacity of modified secretome to attenuate astrocyte reactivity in vitro. HGF-preconditioned NPCs demonstrated increased levels of tissue inhibitor of metalloproteinases-1 and reduced vascular endothelial growth factor compared to untreated NPCs. In reactive astrocytes, HGF-enhanced NPC secretome reduced glial fibrillary acidic protein expression and chondroitin sulfate proteoglycan deposition to a greater extent than either treatment alone, and enhanced neurite outgrowth of co-cultured neurons. These findings have important translational implications for modification of the post-injury milieu and optimization of cell-based strategies for CNS injury.

Keywords: central nervous system injury
glial scar
hepatocyte growth factor
neural progenitor cells
reactive astrocytes
regeneration
Advisor: Fehlings, Michael G.
Investigating the Role of Glycogen Synthase Kinase-3 (GSK-3) in Pathological Progression of Alzheimer’s Disease

Alzheimer’s Disease (AD) is characterized by development of beta amyloid (Aβ) plaques and hyper-phosphorylation of tau in the brain. Glycogen Synthase Kinase-3 (GSK-3) dysregulation has been highlighted as a potential contributor to the onset of disease, and is therefore being investigated as a new therapeutic to ameliorate pathological progression of AD. This research focuses on the GSK-3α isoform and its involvement in Aβ plaque formation and hyper-phosphorylation of tau in mouse models of disease. This research confirms the presence of soluble Aβ in mouse models of AD. Soluble Aβ is accompanied by behavioral deficits. Insoluble Aβ plaques are not abundant, suggesting that soluble Aβ is the culprit in the behavioral deficits. Tau hyper-phosphorylation is present in mouse models of frontotemporal dementia (FTD). Most of these insults are rescued upon partial or full deletion of GSK-3α suggesting that GSK-3α deletion is protective against AD onset.

Keywords: Alzheimer's Disease
CRND8
Dementia
Morris Water Maze
Advisor: Woodgett, Jim R
Ammonium’s Impact on Phase Changes in Urban Grime

Urban grime is a mixed organic-inorganic film that develops on impervious surfaces that allows partitioning of trace atmospheric species from the gas phase. Its chemical composition and physical properties vary, but nitrate and sulfate are always present. Our group recently reported rapid photochemistry of nitrate deposited on films, where the product formation rate depends upon ambient relative humidity. Nitrate’s physical state in grime may affect its photochemistry. Raman spectroscopy was used to differentiate between solid and solution-phase nitrate and sulfate while measuring various mixtures of NaNO3, (NH4)2SO4, Na2SO4, CaCl2, on vacuum grease under dried and humidified conditions, to explore phase changes in a grime-like environment. In the presence of (NH4)2SO4 or CaCl2, nitrate displays a solution-like spectrum even in dried samples. Due to the importance of ammonium’s presence to the phase of nitrate, we performed experiments that monitor evolution of gas phase ammonia from illumination of ammonium-containing proxy grime samples.

Keywords: Ammonium
Atmospheric Chemistry
Nitrate
Phase Change
Urban Grime
Advisor: Donaldson, James
ALCOHOL VS. SACCHARIN: A STUDY ON REWARD CHOICE IN ALCOHOL DEPENDENT AND NON-DEPENDENT ANIMALS

Maladaptive decision-making characterized by drug use despite the availability of many alternative rewards is a key component of substance use disorders. However, the role of changes in decision-making in the enhanced susceptibility to drug dependence has been little studied. The present thesis examined the choice between ethanol and a non-drug reward, saccharin, using the discrete-choice model in ethanol dependent and non-dependent animals. In a separate experiment, rats were trained to self-administer intravenous (i.v.) nicotine and oral saccharin. The two main findings of this thesis are: (1) rats choose oral ethanol and saccharin to a similar degree, in contrast to near-exclusive choice of oral saccharin over i.v. drugs, and (2) ethanol dependence shifts reward preference to exclusive ethanol choice. The increased choice of ethanol over saccharin produced by dependence may be explained by a dependence-induced increase in the positive reinforcing effects of ethanol and a decrease in its negative reinforcing effects.

Advisor: Lê, Anh
Measurement of Turbulent Boundary Layer Induced Surface Pressure Fluctuations

The turbulent boundary layer (TBL) noise generated inside an aircraft can have a detrimental impact on humans. In an effort to better understand TBL physics and measurement techniques, measurements of the fluctuating wall-pressure beneath a TBL have been performed in an anechoic wind tunnel. The measurements were made using an array of pressure microphones provided by Bombardier Aerospace. Analysis of frequency spectra indicated several shortcomings of the array, namely a low saturation limit and electrical issues, however the low speed spectra agree well with the Goody prediction model. Furthermore, an investigation of the relationship between wall-pressure and velocity fluctuations was performed using a pinhole mounted microphone and simultaneous hot-wire boundary layer measurements. This revealed flow interference from the hot-wire apparatus, obscuring the expected relationships and trends. Several areas of improvement have been identified, including higher saturation limit microphones, LDA for velocity measurements, and increasing rigidity of the experimental setup.

Keywords: Aeroacoustics
Turbulent boundary layer
Wall-pressure
Advisor: Lavoie, Philippe
Using Paired Associative Stimulation and Cortical Silent Period to Examine Neural Plasticity in Healthy and Depressed Youth

Background: Major depressive disorder (MDD) is a disorder that typically arises in youth. MDD may results from impaired neural plasticity that can be probed and treated with transcranial magnetic stimulation (TMS). Methods: We evaluated the feasibility of using two common TMS measures, paired associated stimulation (PAS) and cortical silent period (CSP), in youth. PAS and CSP are thought to index NMDA- and GABA-B dependent plasticity, respectively. Results: In our first experiment, we examined 34 healthy adolescents aged 13-19. We found that PAS induced motor cortical plasticity at 15- and 30-min post-PAS. PAS also lengthened CSP in males but not females. In our second experiment, we applied PAS and CSP to a case series of 6 depressed adolescents aged 16-24 and found that both measures were feasible, safe, and tolerable in this population. Conclusions: PAS and CSP are feasible, safe, and tolerable TMS indices of neural plasticity in youth.

Keywords: Cortical Silent Period
Developmental Plasticity
Neural Plasticity
Paired Associative Stimulation
Transcranial Magnetic Stimulation
Advisor: Daskalakis, Zafiris J
Hereditary Breast Cancer in Selected Populations: Screening RECQL Gene in Ontario, Canada, and Exploring BRCA1/2 and PALB2 in the Caribbean

Hereditary breast cancer (i.e., cancer due to an inherited mutation) is imperfectly understood: while 5 to 10 % of breast cancer is hereditary, only 50 % of breast cancer susceptibility has been explained. Increased hereditary breast cancer understanding fosters high-risk patient identification, prevention, early diagnosis, and targeted treatment. To achieve increased knowledge of the hereditary breast cancer landscape, both generation of new information and implementation of prior knowledge in new settings are required. Accordingly, this project had two goals: Firstly, we screened RECQL, a new susceptibility gene candidate, among Ontario breast cancer patients. Secondly, we examined three established genes – namely, BRCA1, BRCA2, and PALB2 – among breast cancer patients in Trinidad and Tobago and Jamaica. Overall, we found that further work was needed to validate RECQL in a heterogeneous population, and that Caribbean screening and prevention could be ameliorated by the inclusion of certain susceptibility genes on gene panels.

Keywords: BRCA1/2
Caribbean and Ontario
Hereditary breast cancer
Mutations and breast cancer risk
PALB2
RECQL
Advisor: Akbari, Mohammad R
Customer Relationship Management using Ensemble Methods

This thesis aims to provide a method for customer relationship management prediction to beat the in-house classification method implemented by the data provider company. By reviewing the common machine learning algorithms, we recommend ensemble methods to predict the targets. Three different ensemble methods are implemented in the thesis: random forest, gradient boosting decision trees and ensemble selection. With the results, we conclude that all ensemble methods outperform the benchmark, reduce the positive predictions and increase the true positive rates. Ensemble selection performs the best, followed by the gradient boosting decision trees. In addition, the results indicate that the ensemble methods' running time significantly increase when compared to the benchmark. The results also indicate that careful feature selection can significantly simplify the training and prediction process. We further discuss the potential applications in marketing using the prediction results and the trade-off between accuracy and computational complexity when applying ensemble methods.

Advisor: Paradi, Joseph C
The Impact of the Mount Polley Tailings Pond Failure on the Sedimentary Record of Quesnel Lake, British Columbia

The Mount Polley tailings pond failure that occurred on August 4, 2014 provided an opportunity to understand the effects of point-source sedimentation events in the sedimentary record. Six sediment cores that were taken at both distal and proximal locations in Quesnel Lake (B.C.) were used to identify if turbidity currents or subaqueous debris flows were generated. Geotechnical (grain size and LOI), mineralogical and copper metal concentrations confirmed the presence of turbidite deposits in four cores. All of these turbidites contained a coarser-grained base and an uppermost fine-grained cap. Two out of the four turbidite deposits that were most proximal to the spill mouth contained mixed basal layers that may signify the energy of the current at that depth. Sediment is focused in the deepest part of the basin. The spill sediments will compress over time but will represent sedimentation rates at 4-5 orders of magnitude larger than Holocene natural rates.

Keywords: lakes
Mount Polley
sedimentation
turbidity current
Advisor: Desloges, Joseph R
Detection of Cystic Fibrosis Transmembrane Conductance Regulator ∆F508 Gene Mutation Using a Paper-Based Nucleic Acid Hybridization Assay and a Smartphone Camera

Diagnostic technology that utilizes paper substrates and device cameras offers opportunities for development of cost effective point-of-care technologies. The translation of assays operating in aqueous solution require further development for implementation in paper substrates. This report presents and compares two methods for determination of oligonucleotides that serve as indicators of Cystic Fibrosis, differentiating wild type and mutant type sequences containing a 3-base deletion. The transduction strategy operates by selective hybridization of dye-labelled oligonucleotides (target or reporters) to capture probes immobilized on quantum dots, and hybridization results in emission of dyes via resonance energy transfer. Detection is based on hybridization of fluorophore labelled target, or hybridization of unlabelled target and labelled reporter in a sandwich assay format. Selectivity to determine mismatched sequences required control of stringency conditions using formamide as a chaotrope. It was determined that both formats can distinguish between wild type and mutant type samples on paper substrates.

Keywords: cystic fibrosis
digital imaging
fluorescence
oligonucleotides
paper
quantum dots
Advisor: Krull, Ulrich J
The Body Triad, Whiteness and Agency: The Not-So-Sporty Experiences of Punjabi-Canadian Women

This thesis explored the physical activity (PA) experiences of 18 Punjabi-Canadian women living in the Greater Toronto Area. It argues that the choice not to participate in PA is an act of agency reflective of the pressures placed on the women. The theoretical frameworks used were the centrality of women’s bodies in social and cultural reproduction, whiteness and critical race theory. The methods used were focus groups coined “chai and chats.” Results revealed that the “Body Triad,” a term I coin, consisting of the “Fat Body,” “Skinny Body” and “Muscular Body” and the dominance of whiteness in Canada impacted the women’s decision to not participate in PA. As a result, the women negotiated these pressures by talking back, “feeling blessed” and challenging existing gendered and racial assumptions about their bodies. This study showed the relationship between gender, immigration and whiteness where Punjabi-Canadian women’s bodies were central to the discussion.

Keywords: body
physical activity
Punjabi-Canadian
racism
South Asian
whiteness
Advisor: Darnell, Simon C.
The Community of CrossFit: An Ethnographic Inquiry

CrossFit has only recently emerged in the sporting landscape and has already developed a massive following. The program is part sport, part exercise system, and is known for its unconventional approach to fitness which combines high intensity exercises with functional fitness, all performed in a group setting. Creating a community is one of the largest claims of the organization and is accredited with much of the positive experiences that keep members coming back. This thesis uses ethnographic data (participant observation and ethnographic) interviews to explore the dynamic of community in one CrossFit box. Findings suggest that CrossFit is best theorized as a community of practice and that studying physical cultures through the framework of community is an effective method to study physical culture by accounting for multiple variables including; personal relationships, autonomy, conflict, and more, amongst members of the group.

Keywords: crossfit
exercise
health
physical cultural studies
sport sociology
Advisor: Atkinson, Michael
Shomeric Islands: Youth Forming Critical Pedagogies in the New Millennium

This research engages Toronto youth in explorative discussions on the educational community framework of the Hashomer Hatzair socialist Jewish youth movement, as an approach to critical pedagogy conducted by and for young people. Employing a practitioner inquiry methodology, the study positions movement members as insiders and knowledgeable practitioners of their common context who engage with central questions related to education and social organization, including raising critically equipped leaders with a drive to incite change. Presented as a multilayered narrative that weaves together community dialogues, the study begins with an illustration of the movement’s modal features, and subsequently documents reflections among Hashomer Hatzair youth educators on their work to move beyond existing arrangements of educational practice in the modern neoliberal era. Findings reveal the significance of centring youth and others from the periphery as seasoned critical partners in fostering local change and resistance.

Keywords: collaborative inquiry
community education
critical pedagogy
local transformation
social movements
youth leadership
Advisor: Simon, Robert
Cavopulmonary Assist Device to Bridge Failing Fontan Circulations

A novel cavopulmonary assist strategy with a multi-lumen cannula powered by an external centrifugal pump is proposed for use in failing Fontan patients. Steady-state computational fluid dynamics simulations are used to characterize hemodynamic performance in an idealized and two patient-specific Fontan pathway models for a wide range of cardiac outputs and pump intake flows, while further transient simulations are conducted for one of the patient-specific models with a periodic cardiac output and coupled to a Windkessel model. Simulations show that the proposed cannula can provide sufficient pressure gain required for cavopulmonary assist. A rigid 3D printed cannula prototype is also tested inside a mock circulation loop. Improvements in mean Fontan pressures from a typical failing circulation occurred at certain flow cases with cannulated assist while venous return flows were altered significantly in the presence of the cannula.

Keywords: Cavopulmonary Assist
Computational Fluid Dynamics (CFD)
Fontan
Hemolysis Index
Advisor: Amon, Cristina H.
Forbes, Thomas