VictorJuiz/thesis huggingface dataset:
Consumer Wristband Activity Monitors as a Simple and Inexpensive Tool for Remote Heart Failure Monitoring
Keywords: consumer
exercise capacity
fitbit
heart failure
physical activity
telemonitoring

Daily physical activity is a strong indicator of heart failure (HF) severity that could help identify at-risk patients before acute decompensation and prevent late readmissions. However, remote-monitoring systems rarely incorporate any activity data. Consumer devices have made continuous activity tracking inexpensive and unobtrusive, but it is not clear whether such devices are suitable for monitoring patients. In this study 50 stable HF outpatients were given Fitbit Flex wristbands activity trackers to wear for two weeks to validate the use of these devices for remote monitoring. We developed metrics of peak activity based on minute-level step data that correlated with clinical cardiopulmonary exercise tests. These consumer devices were also found to be reliable with seamless data collection. Future studies examining the change of these activity metrics over longer periods time in relation to other indicators of HF will help establish the use of consumer devices as a viable remote monitoring tool.
A Gaze into the Mind’s Eye: Gaze as an Indicator of Cortical Reinstatement during Mental Imagery
Keywords: Cortical Reinstatement
Eye Tracking
fMRI
Memory
Mental Imagery
Scanpath

When a previously encountered image is visualized, the spatiotemporal pattern of fixations observed during encoding is often recapitulated. Modern theories posit that fixation recapitulation facilitates, and is facilitated by, the retrieval of detailed internal memory representations. However, there currently exists no direct neuroscientific evidence of this claim. Using an fMRI-based measure of neural reinstatement as a proxy for internal memory representations, we found significant correlations between fixation recapitulation and neural reinstatement during visualization. Additionally, we found a strong correlation between memory performance and neural reinstatement, which mediated a non-significant correlation between memory performance and fixation recapitulation. A secondary goal of the discussed research was the development of a fixation similarity measure optimized for visualization tasks. We found that a measure based solely on fixation angle outperformed a traditional location measure, supporting a chunk-based theory of fixation recapitulation. In total, our results support and extend current theories of fixation recapitulation.
Investigation of Fuel Nozzle Technologies to Reduce Gas Turbine Emissions
Keywords: atomization performance
design methodology
low power
spill return nozzle

With increasing requirements for reduced emissions from future gas turbines, a multitude of research is being conducted into fuel nozzles by gas turbine manufacturers. This thesis focuses on the development of a novel spill return nozzle, to improve combustion efficiency at starting and low power conditions -where combustion efficiency is often the poorest. The spill return nozzle has the advantage of being able to improve atomization performance and reduce internal coking potential, all while being a simple and durable design. The spill return nozzle tech- nology was subsequently applied to a design for an existing small gas turbine combustor, and its improvements over the existing nozzle were demonstrated. The proposed design was also extended to experimental testing in a simplified form. CAD drawings of the components for testing were made, and prototypes were built in plastic using a high accuracy 3D printer. Future work involves conducting experimental tests to validate results.
Vein-on-a-chip: A Microfluidic Platform for Functional Assessments and Staining of Intact Veins
Keywords: blood vessel
function
immunofluorescent staining
Microfluidics
organs-on-a-chip
veins

The ability to perform systematic studies on vein function and structure is of key importance for understanding many vascular diseases and the underlying mechanisms governing transport of cells and macromolecules through the blood vessel wall, both of which are beneficial for drug discovery. Available experimental methods are limited by poor optical access and limited microenvironmental control for in vivo studies, and a partial representation of blood vessel structure in the case of in vitro approaches. In this thesis, I present a microfluidic platform for the in vitro investigation of intact mouse mesenteric vein segment (200-300 μm diameter and 1.5-2 mm length) function under near-physiological conditions. The lumen of the pressurized vein segments are stained on-chip for CD31 to highlight the capacity of our platform for in-situ immunofluorescence staining without the otherwise required tissue processing and sectioning. The selected approach is automatable and reduces the time and staining solution consumption by an order of magnitude compared to traditional methods.
Mechanisms Regulating Intracellular Levels of Helicobacter pylori Cytotoxin Associated Gene A
Keywords: Autophagy
Cancer
Cytotoxin Associated Gene A
Helicobacter pylori
Proteasome
Vacuolating Cytotoxin A

Helicobacter pylori is a gram-negative pathogen that infects 50% of the population worldwide and is the most important risk factor for the development of gastric cancer, one of the leading causes of cancer-related deaths. I propose a complex interplay between two major virulence factors, CagA and VacA, in mediating disease. VacA is a pore-forming cytotoxin that disrupts the autophagy pathway. Current evidence suggests that the oncoprotein CagA can be degraded by autophagy. I demonstrate that the proteasome is involved in degrading CagA. Furthermore, I show that during chronic infection, VacA-disrupted autophagy promotes CagA accumulation through the concerted efforts of disrupted autophagy and impaired proteasomal clearance. Lastly, I present preliminary evidence of CagA accumulation in infected human gastric organoids, mediated by VacA-disrupted autophagy. Together, these studies provide insights into the mechanisms of regulation of CagA levels in host cells and the synergistic relationship between VacA and CagA during infection and disease.
Investigating Accelerated Long-term Forgetting: The Effects of Associative and Item Memory, and Semantic Relatedness on Long-term Retention
Keywords: Accelerated Long-Term Forgetting
Consolidation
Hippocampus
Long-Term Memory
Memory
Temporal Lobe Epilepsy

We sought to create a test that could delineate memory for semantically related and unrelated associative and item information, for future use with patients with temporal lobe epilepsy in the study of accelerated long-term forgetting. Healthy participants studied semantically related and unrelated object-scene pairs and completed forced-choice recognition tasks for item and associative memory over variable delays. Participants recognized significantly less associative than item stimuli by 6-hours post-study due to degraded memory for associative stimuli. While item memory remained stable, memory was boosted for associative stimuli after a night of sleep but continued to decline thereafter. These effects were particularly robust for pairs that were semantically unrelated, as semantically related pairs demonstrated superior memory across the delays with relatively minimal decay over time. Possible neurobiological correlates of forgetting for the different types of stimuli in the context of current theories of consolidation are discussed, and implications for the phase II patient study are explored.
Emergency Department Wait Time Modelling and Prediction at North York General Hospital
Keywords: ARIMA
emergency department
wait time

At North York General Hospital Yellow Zone (YZ), providers seek real-time forecasts of waiting times to improve communication and prescribe actions to relieve patient crowding. Time series of patient waits to physician assessment (PIA) and to discharge from the YZ (PTE) were collected. Multivariable regression with ARIMA errors was fit to determine the patient-based and systematic predictors of wait times for YZ patients at time of arrival. A regression on occupancy with ARIMA(1,0,0)(0,1,1)24 errors yielded the lowest error in forecasting PIA. Accuracy improved when grouping patients by acuity and complaint. ARIMA methods yielded low accuracy in forecasting PTE, and no correlations were found between PTE and acuity. 90% of patients waited up to 47.88 minutes more than predicted for PIA and up to 118 minutes more for PTE. The results suggest that ARIMA models have utility in forecasting PIA but that alternative models should be used to improve PTE prediction.
Hemocompatibility of Degradable Polar Hydrophobic Ionic Polyurethane for Blood Contact Applications
Keywords: Biocompatibility
Biomaterial
Degradation
Hemocompatibility
Material characterization
Polyurethane

Biomaterial hemocompatibility is an important concern in the development of synthetic blood-contacting surfaces, specifically to help mitigate thrombosis which can lead to blood vessel occlusion or device failure. A novel biomaterial, degradable polar hydrophobic ionic polyurethane (D-PHI), is studied for its effect on hemocompatibility. Furthermore, this thesis explores a new subject; changes in hemocompatibility of biomaterials over the course of degradation, using both D-PHI and poly(lactic-co-glycolic) acid (PLGA) as important classes of materials that are finding their way into numerous applications. The key results from this work are that D-PHI elicits a low level of clotting that is likely initiated by complement activation; however, it is anticipated that this activation favours controlled wound-healing. Furthermore, degradation appears to significantly affect hemocompatibility for PLGA suggesting the need for further studies. Finally, this work highlights the importance of including white blood cells (WBCs) in any platelet-biomaterial testing.
Construction Safety Climate in Ontario: A Longitudinal Study
Keywords: Construction
Safety

The aim of this paper is to document changes in the relationship between demographics, attitudes, physical symptoms, psychological symptoms, and accidents over time in the construction industry. This longitudinal study compares periodic measures of the construction safety climate in Ontario in 2004/6 and 2014. A total of 442 self-administered questionnaires were collected from 22 construction sites in 2014. The 2014 data were compared to 911 valid questionnaire responses obtained in 2004/06 from 84 construction sites across Ontario. The questionnaire contained 105 questions and took participants 15 minutes to complete. Demographic data remained consistent over time. The participants had an average experience level of 15 years, having spent a median of 2.5 years with their current employer. Considerable attitudinal improvements were observed in the areas of leadership, coworker perception, supervisor perception, management perception, and safety program perception. The prevalence and occurrence of physical symptoms, psychological symptoms, and accidents decreased over time.
Novel Methods to Reduce Muscle Fatigue Using Multi-electrode Functional Electrical Stimulation in Isokinetic Knee Extension Contractions
Keywords: Functional electrical stimulation
Isokinetic
Multi-electrode
Muscle fatigue
SDSS
Sequential

Muscle fatigue, a major limiting factor in the use of functional electrical stimulation, can be countered through multi-electrode sequential stimulation. To apply this method clinically, our lab developed a generic adapter. The purpose of this thesis project was (1) to test the adapter’s performance and (2) to investigate whether two sequential techniques, namely Spatially Distributed Sequential Stimulation (SDSS) and Sequential Multiple Muscle-Head Stimulation (SMHS), are capable of inducing less fatigue than Single Electrode Stimulation (SES) in isokinetic knee extension contractions. Thirteen able-bodied individuals participated in a three-day study. Performance of the adapter was found to be accurate within acceptable error. Both SDSS and SMHS resulted in significantly less fatigue than SES as measured by fatigue index and torque peak mean. The less low frequency fatigue observed during SDSS and SMHS may explain the lower fatigue. SDSS and SMHS delivered via adapter pose an attractive alternative to SES during clinical applications.
Superhydrophobic Ceramic Coatings by Solution Precursor Plasma Spray
Keywords: Ceramics
Solution precursor plasma spary
Superhydrophobic coating

Superhydrophobic surfaces exhibit superior water repellent properties, and they have remarkable potential to improve current energy infrastructure. Substantial research has been performed on the production of superhydrophobic coatings. However, superhydrophobic coatings have not yet been adopted in many industries where potential applications exist due to the limited durability of the coating materials and the complex and costly fabrication processes. Here presented a novel coating technique to manufacture ceramic superhydrophobic coatings rapidly and economically. A rare earth oxide (REO) was selected as the coating material due to its hydrophobic nature and strong mechanical properties, and deposited on stainless steel substrates by solution precursor plasma spray (SPPS). The as-sprayed coating demonstrated a hierarchically structured coating topography, which closely resembles superhydrophobic surfaces in nature. Compared to smooth REO surfaces, the SPPS superhydrophobic coating improved the water contact angle by as much as 65° after vacuum treatment at 1 Pa for 48 hours.
Velutin Modulates the Expression of HIF-1a via the NF-kB Pathway during Osteoclastogenesis
Keywords: Hif-1a
NF-kB
Osteoclast
osteoclastogenesis
Porphyromonas gingivalis
Velutin

HIF-1a has been implicated in periodontal tissue inflammation, while polyphenols are known anti-inflammatory natural compounds that can modulate the NF-kB pathway. Our aim was to investigate HIF-1a expression through NF-kB modulation by the polyphenol velutin during osteoclastogenesis. Methods: RAW 264.7 cells were evaluated with/without RANKL (30ng/mL)/Pg LPS (1µg/mL) and treated with velutin (0.5-2µM) to evaluate nuclei morphology, viability, osteoclast differentiation, and HIF-1a expression. Results: DAPI staining showed no alteration in the morphology of cells nuclei (p>0.05). Velutin did not induce cell apoptosis based on caspase 3/7 analysis (p>0.05) and Alamar blue showed no toxicity to the cells (p>0.05). TRAP assays demonstrated reduction in osteoclast formation by velutin (p
Empathy and the Subjective-behavioural Effects of D1 and D2 Receptor Blockade in Pathological Gamblers
Keywords: Dopamine
Empathy
Liking
Pathological Gambling
Wanting

This study assessed the relationship between Empathy and reinforcing effects of gambling and a psychostimulant drug, in 30 otherwise healthy pathological gamblers (PGs). To explore the roles of dopamine D1 and D2 receptors in these relationships, subjects received either: D2 antagonist, haloperidol (3-mg) or D1-D2 antagonist, fluphenazine (3-mg), in a placebo-controlled, double-blind, counterbalanced design. On separate sessions, subjects played a 15-minute slot machine game and received d-amphetamine (AMPH; 20-mg, oral). Under placebo, Empathy correlated positively with Desire to Gamble (DTG) at all time-points in both groups. Haloperidol negated, whereas fluphenazine enhanced, the correlation between Empathy and pleasurable effects of the slot machine. Haloperidol enhanced, whereas fluphenazine attenuated, the correlation between Empathy and DTG under AMPH. Results suggest post- synaptic D2 receptors may mediate Empathy-related differences in Liking of gambling; D1 receptors may mediate Empathy-related differences in Wanting to gamble under AMPH in PGs. Low statistical power and restricted generalizability were limitations.
Youth Athletes' Interpretations of Punishment in Hockey
Keywords: Coach-athlete relationship
Hockey
Punishment
Youth Athletes

The purpose of this study was to explore competitive youth hockey athletes’ interpretations of punishment. Semi-structured interviews and concept maps were conducted with 12 (7 male and 5 female) hockey athletes between the ages of 11-13 years. All data were analyzed according to inductive thematic analysis (Braun Clarke, 2006). Results revealed that punishments reportedly occurred in competitive hockey frequently in the forms of benching, yelling, and forced physical conditioning; in addition, these methods appear to be normalized within the sport context, and reportedly have detrimental effects on athletes. The findings are interpreted according to various theoretical frameworks, which include: the sport ethic (Hughes Coakley, 1991), cognitive-motivational-relational theory (Lazarus, 1999), psychosocial development (Erikson, 1968), and youth sport attrition (Weiss Williams, 2004). Implications and recommendations for future research in this field of study are discussed.
Testing the Sensorimotor Fluency Account of Mimicry
Keywords: Human mirror system
Mimicry
Processing fluency

Mimicry is a pervasive and ubiquitous human behaviour with generally positive consequences, resulting in increased liking, closeness, and smoothness between interaction partners. Whereas previous research has stressed the affiliative aspect of these consequences, recent research suggests that these consequences may also arise because of the sensorimotor fluency with which mimicry is achieved. I tested three key hypotheses of this model in two experiments and found no support for a sensorimotor fluency account of mimicry. Implications of this research are discussed.
The Face of a Nation: The Effect of Nationality on Face Memory and Perception
Keywords: face perception
ingroup favouritism
memory
nationality
person perception

Nationality is a pervasive group membership, and previous research has variously demonstrated its potency. However, little work has investigated nationality’s relationship with person perception, an area ripe for research in today’s globalized world. Thus, the aim of this thesis was to understand how nationality affects one’s perception and memory of others. I tested how randomly pairing faces with Canadian and foreign flags affected Canadians’ memory and trait evaluations for these faces and whether nationalism predicted ingroup favouritism. I also compared memory differences for ostensible national ingroup and outgroup members to that for university ingroup and outgroup members to determine the relative importance and strength of nationality over other social identities. Across three studies, I found that Canadian participants recognized faces randomly paired with the Canadian flag better than those paired with a foreign flag, suggesting that nationality labels can affect memory for others, which has important implications for cross-national interactions.
Increasing Void Fraction of the Polypropylene Foams Blown with Chemical Blowing Agents in High Temperature Extrusion
Keywords: Chemical Blowing Agents
Extrusion
High Temperature
Polymeric Foams
Polypropylene
Void Fraction

The global demand for the polymeric foams especially Polypropylene (PP) foams is increasing rapidly. Some industrial processing of the PP foam need high processing temperature. But, there are only a few research has been done on high temperature processing as the quality of foam deteriorates in that condition. Moreover, Physical Blowing Agents (PBA) need additional accessories to process the foam. But usually industries are reluctant to change their existing system to get foamed output initially. This thesis develops an approach to manufacture PP foams with Chemical Blowing Agents (CBA) in high temperature extrusion. In the first step, a series of fundamental studies have been carried out by investigating the effect of different chemical blowing agent and content, pressure drop rate and residence time on the foaming behavior of polypropylene. And then, optimized parameters are applied and the combination effect of CBA-PBA and the effect of nucleating agents has been examined.
Linear Stability Analysis, Dynamic Response, and Design of Shimmy Dampers for Main Landing Gears
Keywords: Dynamic response
Main landing gears
Shimmy dampers
Stability analysis
Vibrations

This thesis presents the linear stability analysis and dynamic response of shimmy dampers for main landing gears. The stability analysis is performed using a single tire landing gear model along with the dynamics of the shimmy dampers and the stretched string tire model. The dynamic response of each damper is obtained through a multibody model developed in MSC Adams and validated using existing literature. Two shimmy dampers are the focus of this study, one developed by Boeing and the other by UTC Aerospace systems. Finally, a new and improved shimmy damper is proposed showing the stability regions and its dynamic response. The proposed damper is lighter, easier to manufacture, to install, and to maintain, and has an overall better dynamic performance.
Bioengineering Human Scaffold-free Cartilage Constructs Using Paediatric Auricular Tissue
Keywords: Auricular
Cartilage
Microtia
Scaffold-free
Tissue Engineering

Currently, patients with external ear deformities rely on hyaline cartilage grafts or silicone prosthesis to provide them with adequate external ear reconstruction. Scaffold-free auricular tissue engineering provides a means of creating patient specific cartilage constructs solely using their own cells, ensuring biocompatibility, long term stability, and reduced morbidity. Here, we have developed a simple method for generating scaffold-free auricular constructs using paediatric auricular cartilage remnants. High cell density micromass cultures treated with chondrogenic medium for prolonged periods result in mechanically stable cartilage constructs resembling native paediatric auricular cartilage mechanically, histologically, immunohistochemically, and biochemically.
Audio Cueing and Negative Adaptation in Older and Younger Drivers Using Lane Departure Warning Systems
Keywords: adaptation
audio cueing
automation
older drivers

A Lane Departure Warning Systems (LDWS) is an automation system that can be integrated in vehicles. Empirical research has demonstrated conflicting results about the effectiveness of LDWS, which may be attributable to inconsistent warning cues, adaptation effects, and differences among user populations. In this thesis, I investigated whether meaningful or non-meaningful auditory cues are more effective in improving lane keeping in older and younger drivers, and if adaptation occurs with the use of either/both cue types when the LDWS was intermittently turned off. Results showed LDWS were initially helpful in reducing lane deviations, regardless of cue type, with non-meaningful cues showing slightly greater effectiveness, particularly in older adults. However, following exposure to LDWS, drivers exhibited short-term negative adaption to the system, displaying significantly more and larger lane deviations when the system was on compared to when it was off. Significant adaptation differences between younger and older adults were not observed.