VictorJuiz/thesis huggingface dataset:
Proliferation of Pathogenic Biofilms within Sealer-root Dentin Interfaces is Affected by Sealer Type and Aging Period
Keywords: resin-dentin interface, endodontic sealer, resin-composite, biofilm, E faecalis, fluorescence microscopy

Objective: To assess biofilm proliferation within the sealer-dentin interfaces of methacrylate resin-based sealers, self-etch (SE) and total-etch (TE), and an epoxy resin-based sealer (EP). Methods: Standardized human root specimens were filled with the test materials and were aged for 1 week, 1, 3 or 6 months in saline (n=3/group). Monoclonal biofilms of Enterococcus faecalis were grown on the specimens for 7 days in continuous media reactor. The extent of biofilm proliferation of E. faecalis within the sealer-dentin interface for each material at each incubation period was assessed using fluorescence microscopy of dihydroethidium-stained specimens. Results: TE had less biofilm proliferation than EP and SE (p<0.01). Deeper biofilm proliferation was detected in SE and EP specimens aged for 1 and 3 months than those aged for 1 week or 6 months (p<0.05). Conclusion: Self-etch and epoxy resin-based sealers were more susceptible to interfacial biofilm proliferation than total-etch system at shorter incubation periods.
Chemical Modeling of Ammoniacal Solutions in Ni/Co Hydrometallurgy
Keywords: Electrolyte Thermodynamics
Ni Hydrometallurgy
OLI Software
Chemical Modeling
Ammnia Recovery

Chemical modeling has become an important subject of research in applied thermodynamics for designing, developing, optimizing and controlling of different industrial processes. In this work, a new database for successful modeling of solid-aqueous phase equilibria in specific hydrometallurgical processes was developed using the Mixed Solvent Electrolyte (MSE(H3O+)) model of the OLI Systems software. The ionic interaction parameters between dominant species in the solution were determined by fitting available binary and ternary experimental data such as mean activity, heat capacity and solubility data; then they were validated in multi-component systems. Developed model predicted the phase behaviour in ammoniacal solutions containing cobalt, nickel, copper, and zinc in the Copper Boil process. New sets of double-salt solubility data were measured and used for accuracy validation of the model. Using HSC 6.1 software linked with MSE model, the copper boil processes was simulated successfully to provide some practical recommendations for the optimum process operation.
The Experiences of Immigrants Seeking Healthcare in Toronto
Keywords: Immigrants
Migrants
Health
Healthcare
Mental Health
Food security
Health Services
Immigration Status
Undocumented Immigrants
Refugees
Landed Immigrants

Background: The provision of healthcare for immigrants is a global issue. Understanding the complexities of migrant’s experiences seeking healthcare is essential to improving their ability to access healthcare. This qualitative study reports on the experiences seeking healthcare for three groups of migrants. Methods: Seventeen one-on-one interviews were conducted with Spanish-speaking women through an interpreter. Community-based participatory action research was the framework utilized for this study. Results: An individual’s immigration status emerged as the single most important factor affecting both an individual’s ability to seek out healthcare and what their experiences are when trying to access healthcare. Conclusion: This study brings to light two issues that are not discussed in great depth in the migrant health service literature. The immigration status of migrants is the largest factor affecting their ability to seek healthcare. Food security is a very stressful issue for many refugees and undocumented immigrants.
Elucidating the Mechanisms of Transposable Elements using Experimental and Bioinformatic Approaches: The hAT Superfamily of Transposable Elements in the Genome of Aedes aegypti and TE Displayer
Keywords: Transposable Elements
Aedes aegypti
TE Displayer
Transposon Display

Transposable elements (TEs) are found in nearly all eukaryotic genomes and are a major driving force of genome evolution. The hAT superfamily of TEs are found in a variety of organisms, including plants, fungi, insects and animals. To date, only 14 hAT TEs in the Aedes aegypti genome have been annotated as having a hAT transposase coding sequence. In this study, extensive bioinformatic approaches have been employed to find hAT TEs that encode transposases in the A. aegypti genome. A total of six newly-identified TEs belonging to the hAT superfamily were discovered in the A. aegypti genome. Furthermore, a computer program called TE Displayer was developed to analyze TEs in genome sequences. TE Displayer detects TE-derived polymorphisms in genome datasets and presents the results on a virtual gel image. TE Displayer enables researchers to compare TE profiles in silico and provides a reference profile for experimental analyses.
The Effects of Cue Familiarity on Episodic Memory, Scene Construction, and Imagining the Future
Keywords: Episodic Memory
Imagination
Scene Construction
Familiarity
Spatial Memory
Vividness

Recent research has revealed many similarities between episodic memory, scene construction, and imagination of the future. It has been suggested that scene construction is the common process underlying memory and imagination, but no study to date has directly compared all three abilities. The present study compared retrieval time, ratings of detail and vividness for episodic memories, remembered scenes and imagined future events cued by landmarks of high and low familiarity. Memories, scenes, and imagined episodes based on a more familiar landmark as a cue were more quickly retrieved, more detailed, and more vivid. This study was the first to demonstrate the effects of frequent encounters with a cue on memory, scene construction and imagination of the future. Additionally, consistent results across conditions, as well as stronger effects in the scene construction condition, provide further evidence of a possible interdependence of episodic memory, imagination of the future, and scene construction.
Commercial Fluorosurfactants and their Metabolites in Human Blood
Keywords: fluorochemicals
fluorosurfactants
environmental chemistry
human exposure
biological monitoring
temporal study

Fluorinated chemicals have the advantage of both lipophobic and hydrophobic behaviour, leading to broad industrial and commercial use. Fluorosurfactants, for example, are used in applications, such as grease-proofing food packaging, which result in human exposure. Human blood serum, in this work 100 German serum samples dating from 1982 to 2009, is a common matrix for detection of fluorochemicals. Here the most extensive temporal study to date of one class of fluorosurfactant (polyfluoroalkyl phosphate diesters, diPAPs) in human serum is presented. Additionally, another class of fluorosurfactant (sulfonamide-based PAPs, SAmPAPs) was detected in humans for the first time with temporal trends which echo industrial production. Metabolites of diPAPs and SAmPAPs were also quantified, showing temporal trends that relate to the diPAP and SAmPAP levels. Because diPAP and SAmPAP metabolites are environmentally persistent and raise human health concerns, it is important to understand these indirect sources of exposure.
Rational Reform of Housing Access Policy in Ontario
Keywords: housing
public housing
social housing
affordable housing
low-income housing
rental housing
housing rights
right to housing
residential tenancies
rent control
lease
contract
property
poverty
welfare
planning
rent-geared-to-income
RGI
subsidy
zoning
maximin
law
distributive justice
corrective justice
efficiency
Pareto
Kaldor-Hicks
Ontario
Canada
shelter
ICESCR
International Covenant on Economic, Social and Cultural Rights
Charter
structural theory
elasticity
vacancy decontrol

Ontario’s current regulatory approach to low-income housing lies between two primary challenges: the human right to housing, and political/fiscal constraints. This thesis draws on legal theory and economic analysis of law to articulate the proper goals of housing access policy. A structural theory is proposed to explain the normative relationship between efficiency, communitarianism and justice in housing. An array of regulatory options are compared and considered in light of the features that characterize Ontario’s low-income rental housing markets. This analysis favours demand-side housing subsidies to low-income households, combined with supply-side tax expenditures to improve elasticity in the low-income rental market. Further reform of rent and covenant controls, social and affordable housing supply, and land use planning is recommended to ensure an efficient residential tenancy market. These reforms are offered as a framework for the implementation of the human right to housing in Ontario.
Chromium and Neodymium Complexes of bis-Phosphinimine Pincer Ligands and Their Behaviour in 1,3-Butadiene Polymerization
Keywords: polybutadiene
chromium
neodymium
phosphinimine
pincer ligand
1,3-butadiene

Polybutadiene, the homopolymer of 1,3-butadiene, is a synthetic rubber especially important in the production of tires. Industrially, it is polymerized using multi-site catalysts that do not offer significant control over molecular weight distribution resulting in polymers with poor mechanical properties. Single-site polymerization of 1,3-butadiene results in narrow molecular weight distribution and thus increased impact resistance and durability. Complexes of chromium and neodymium bearing bis-phosphinimine pincer ligands have been synthesized and studied for their behavior in 1,3-butadiene polymerization in combination with methylaluminoxane. The complexes that were active produced highly cis-1,4-polybutadiene with high molecular weight and narrow polydispersities. The co-polymerization of acrylonitrile and 1,3-butadiene with the bis-phosphinimine chromium (III) complexes and methylaluminoxane to produce nitrile-butadiene rubber was also explored. The insertion of 1,3-butadiene into nickel-methyl and nickel-hydride complexes bearing the bis-phosphinimine pincer ligands was examined using nuclear magnetic resonance spectroscopy and will also be discussed.
The Attorney General’s Obligation to Report Breaches of Rights in Proposed Legislation: How the Canadian and New Zealand Reporting Cultures Differ
Keywords: Canadian Charter of Rights and Freedoms
New Zealand Bill of Rights Act 1990
Attorney General
Human Rights
Legislation
Parliament
Constitutional law
Bill of rights

This paper examines the Attorney General’s obligation, in Canada and New Zealand, to report on inconsistencies in proposed legislation with the Canadian Charter of Rights and Freedoms and the New Zealand Bill of Rights Act 1990. Although the obligations are similar, the Canadian and New Zealand Attorneys General have developed very different reporting cultures. The Canadian Attorney General has never issued a report; the New Zealand Attorney General has issued many. This paper’s thesis is that the different reporting cultures are attributable to the different constitutional structure in each jurisdiction and different understandings of the independence of the Attorney General. Under this analysis, the usefulness of comparative analysis between the two jurisdictions is limited: constitutional differences cannot be ignored. The paper evaluates proposed changes to the reporting obligation in each jurisdiction in light of this analysis.
3D Printing: Convergences, Frictions, Fluidity
Keywords: 3D printing
digital culture
material culture
design
craft
Makers
DIY
Critical Making

The emergence of desktop ‘3D printing’ is not only a technological development, but equally a social and economic phenomenon that actively (and often contentiously) co-produces the material and ideological infrastructures it occupies. Reflecting wider momentum toward digital-material convergence, the current “revolution” in desktop digital fabrication is fundamentally attributable to the efforts of decentralized Maker and DIY communities who, connected through digital networks, practice citizen-led technological experimentation and occupy novel spaces for innovation and entrepreneurship. Employing hybrid qualitative methods that include Critical Making, this research explores the following themes: rhetoric versus reality, the divisive notion of ‘digital craft’, perceptions of authenticity, as well as cultural momentum manifested in decentralization, convergence, stratification, and iteration. An overarching theme emerges: 3D printing is a fluid phenomenon – in literal, metaphorical, technological and cultural ways.
Access to Justice and the Institutional Limits of Independent Courts
Keywords: judicial independence
access to justice

Canadian citizens’ inability to access courts has been a subject of controversy for decades. Despite widespread evidence that Canada’s legal aid system is faltering, governments continue to be unwilling to commit the resources necessary to remedy the problem. In this thesis, the author argues that people’s inability to access courts and obtain legal representation not only has implications for their rights and interests, but may also undermine judicial independence. Judicial independence, the author claims, is best understood as a variable bundle of rights, guarantees and powers conferred on courts and judges that preserves and enhances their abilities to adjudicate impartially, maintain a constitutional distribution of powers and uphold the rule of law. Since people’s inability to access courts can impair the judiciary’s ability to preserve these values, judicial independence is undermined. The author claims that it is possible to correct problems of inaccessibility by appointing state-funded counsel in appropriate circumstances.
On the Flow Characteristics behind a Backward-facing Step and the Design of a New Axisymmetric Model for their Study
Keywords: separated shear flows
backward-facing step

An extensive review was made to study the wake characteristics of a backward-facing step. Experimental and numerical studies of the backward-facing step suggest that the wake of a separated shear layer to be dependent on parameters such as: expansion ratio, aspect ratio, free stream turbulence intensity, boundary layer state and thickness at separation. The individual and combined effects of these parameters on the reattachment length are investigated and discussed in detail in this thesis. A new scaling parameter, sum of step height and boundary layer thickness at separation is proposed, which yields significant collapse of the available data. Based on the literature review, an axisymmetric model is designed for further investigating the dynamics of the flow independent of aforementioned parameters. Additionally, porous suction strips are incorporated to study the step wake characteristics independent of Reynolds number. This model has been built and will be tested extensively at UTIAS.
Understanding Cognitive Function In Older Adults With Type 2 Diabetes Mellitus via Environmental Stress in the Functional Magnetic Resonance Imaging Environment and Metabolic Stress Associated with Glucose Ingestion
Keywords: Nutrition
Neuropsychology
Cognition
Imaging

The objectives were to explore cognitive function in older adults with Type 2 Diabetes Mellitus (T2DM) through two studies: 1) a pilot study involving the metabolic stress of glucose ingestion and the environmental stress of a functional magnetic resonance imaging (fMRI) environment and 2) an fMRI study exploring the neural mechanisms through hippocampal and prefrontal functional imaging during memory and executive functioning tasks. In T2DM subjects, environmental stress produced greater impairment in memory performance and metabolic stress produced overestimation of memory performance, with similar executive functioning, relative to healthy subjects (pilot study). T2DM subjects also sowed reduced hippocampal and greater prefrontal activation compared to healthy subjects (fMRI study). Moreover, the metabolic stress caused greater hippocampal and prefrontal activation in healthy subjects relative to placebo (fMRI study). These results indicate plausible neural mechanisms behind T2DM- and stress-associated cognitive impairments that can be used for future improvements in cognitive retention and rehabilitation.
Shear & Extensional Effects in Internal Flows of Dilute Polymer Solutions
Keywords: elastic effects, polymer solutions, shear, extension, boger fluids

Shear and extensional flows of dilute polymer solutions were studied experimentally in an attempt to understand the mechanism of polymer-induced drag reduction. A flowcell capable of simulating the dynamics of a turbulent boundary layer, involving the motion of counter-rotating vortices, was designed and fabricated. The pressure drop across the flowcell was measured for different flow arrangements, first with a Newtonian fluid and then with drag reducing, dilute polymer solutions. The pressure drop in excess of the Newtonian baseline, after accounting for viscous effects, was used as a measure of elastic effects. With the dilute polymer solutions, elastic effects were observed both in shear, extensional, as well as presheared extensional flows. These effects can be attributed to additional normal stresses generated by shearing. For extensional flows, the observed effects were independent of elongation rates, indicating that a conclusion regarding the mechanism of drag reduction cannot be made from the flowfield investigated.
Effects of Cannabis Dependence on Cognitive Function in Males with Schizophrenia
Keywords: schizophrenia
addiction

Background: Cognitive impairment and cannabis use are common among patients with schizophrenia. However, the moderating role of cannabis on cognition remains unclear. Aim: We sought to examine cognition and symptomatology as a function of cannabis use patterns in schizophrenia. Methodology: Cognition was assessed in male outpatients with current cannabis dependence (n=18), historical cannabis dependence (n=21) and patients with no lifetime use (n=8). In addition, we explored the relationship between cumulative cannabis exposure and cognition among lifetime users. Results: Lifetime cannabis users demonstrated better processing speed than patients with no lifetime use. Notably, patients with current dependence exhibited robust relationships between cumulative cannabis exposure and cognition; associations were absent in former users. Conclusions: Cannabis status has minimal effects on cognition in schizophrenia. However, cumulative cannabis exposure significantly impairs cognition in current, but not former users, suggesting that the state dependent negative effects of cannabis may be reversed with sustained abstinence.
Generation of Planar Cell Polarity (PCP) in vitro for Epithelium Tissue Engineering
Keywords: Epithelium Tissue Engineering
Planar Cell Polarity

Engineering epithelium with correct structure is essential for generating functional tissue. During tissue development, cells organize in defined patterns through cellular signalling. Artificial generation of the signalling that organizes cells within the tissue offers a novel approach for engineering tissues with appropriate structure. Planar cell polarity (PCP) is a cellular signalling pathway involved in the organization of epithelial cells. Our goal is to study the effect that co-culturing genetically distinct populations of epithelial cells, with variable levels of one of the core PCP proteins, has in epithelial cell sheet organization. MDCK cells transduced with a tagged PCP core protein (GFP-Vangl2) and wild type MDCK cells were co-cultured side-by-side. The effect of tight junction and cilia formation, and localization of the GFP-Vangl2 protein were evaluated. The results suggest that tight junction and cilia formation are not affected. On the other hand, the GFP-Vangl2 protein seems to be affected at some level.
Indications of Stress Corrosion Cracking Resistance in Alloy 82 Dissimilar Metal Welds in Simulated Primary Water Environments
Keywords: Internal Oxidation
Stress Corrosion Cracking
Oxidation
Alloy 82
Alloy 800
Alloy 600
Cracking
Corrosion
Nuclear
Primary Water

Joints between carbon steel and Alloy 600, containing Alloy 82 weld metal, were exposed to two steam-hydrogen environments considered to simulate exposure to primary water conditions in a Pressurized Water Reactor (PWR) or Canada Deuterium Uranium (CANDU) reactor. The welds were found to have elevated and variable iron contents due to dilution by carbon steel during welding. This gave the Alloy 82 weld, near the inner surface of the component, an iron content approaching that of Alloy 800. A potentially protective external iron oxide film formed on the inner surface of the weld. However, the chromium content throughout the weld is below that which would form an external chromium oxide. The results indicate that low chromium content causes internal oxidation throughout the weld and potentially below the external iron oxide which could lead to Primary Water Stress Corrosion Cracking (PWSCC).
Improving Credit Card Fraud Detection using a Meta-learning Strategy
Keywords: data mining
credit card
meta-learning
artificial intelligence
algorithms
fraud detection

One of the issues facing credit card fraud detection systems is that a significant percentage of transactions labeled as fraudulent are in fact legitimate. These “false alarms” delay the detection of fraudulent transactions. Analysis of 11 months of credit card transaction data from a major Canadian bank was conducted to determine savings improvements that can be achieved by identifying truly fraudulent transactions. A meta-classifier model was used in this research. This model consists of 3 base classifiers constructed using the k-nearest neighbour, decision tree, and naïve Bayesian algorithms. The naïve Bayesian algorithm was also used as the meta-level algorithm to combine the base classifier predictions to produce the final classifier. Results from this research show that when a meta-classifier was deployed in series with the Bank’s existing fraud detection algorithm a 24% to 34% performance improvement was achieved resulting in $1.8 to $2.6 million cost savings per year.
In and Out of Consciousness: Sustained Electrophysiological Activity Reflects Individual Differences in Perceptual Awareness
Keywords: Visual Awareness
Visual Working Memory
Perception
Consciousness

Examining the neural correlates associated with the moment a stimulus enters or exits conscious awareness is one way to potentially identify the neural mechanisms that give rise to consciousness. In the present study, we examined neural activity using electroencephalogram (EEG) recordings while participants observed a bilateral shape-from-motion (SFM) display. While the display is in motion, the observer perceives an object that is immediately segregated from a noisy background. After the motion stops, the observer’s experience of the object remains momentarily in awareness, before it eventually fades out of consciousness back into the noisy background. Consistent with subjective reports of perceptual experience, we observed a prominent sustained posterior contralateral negativity (SPCN), but only in conditions associated with sustained awareness. Importantly, the amplitude of the SPCN was correlated with individual differences in visual awareness, suggesting that this activity plays a significant role in the maintenance of objects in consciousness.