VictorJuiz/thesis huggingface dataset:
Mechanical Aging of Thermoset Polymer
Keywords: Aging
Mechanical properties
Molecular dynamics
Thermoset polymer

Polymer aging is a time-dependent process of various changes to the material under the influence of one or more environmental factors. Thermoset polymers experience mechanical properties degradation when subjected to different aging conditions. It is the objective of this research to conduct accelerated tests, supported by limited MD simulations, to determine the degradation behaviors of an epoxy polymer under water immersion, UV radiation, and elevated temperature. To investigate the effect upon mechanical properties, tensile tests were conducted for more than 270 days. In addition, molecular dynamics (MD) simulations were conducted to investigate the water absorption effect on the elastic properties of the epoxy. The results revealed that water absorption has both plasticization and anti-plasticization effects; UV radiation could lead to post-curing reactions and epoxy embrittlement; thermal aging can also further cure the epoxy initially, but longer thermal aging leads to softening effect.
Cell Specific Expression, Regulation and Consequences of GITRL Induction in a Persistent Viral Infection
Keywords: GITR
GITRL
LCMV
TNFRSF18
TNFSF18
Type I Interferon

Co-stimulation of T cells through Glucocorticoid-Induced Tumour Necrosis Factor Receptor-Related Protein (GITR) contributes to viral control during persistent lymphocytic choriomeningitis virus (LCMV) infection. Herein, we demonstrate that expression of its ligand, GITRL, is restricted to the onset of infection. GITRL induction is dependent on type I interferon (IFN-I) both in vitro and in vivo. Accordingly, monocyte-derived inflammatory antigen presenting cells (infAPC) with high IFN-I sensitivity were identified as the dominant GITRL expressers. Selective deletion of exon2 in their GITRL with Lysozyme-M-Cre recapitulated defects reported in global GITR-/- mice. Furthermore, we showed that infAPC were weak APC and phospho-signaling downstream of GITR was temporally segregated from T cell activation suggesting a post-priming event. Instead, GITR played a pro-survival role in sustaining CD4 T cell responses early post-infection through up-regulation of IL2RÎą, IL7R, and OX40. Together, this thesis provides insights into the regulation and mechanism of GITR co-stimulation during LCMV clone13 infection.
Physiological Monitoring During Cardiac Arrest: Derivation and Validation of Capnogram Algorithm
Keywords: Cardiac Arrest
End-Tidal Carbon Dioxide
Resuscitation

Cardiac arrests are life threatening medical emergencies that affect over 40,000 individuals in Canada each year. Cardiopulmonary resuscitation (CPR) continues to be one of the few first-line interventions that improves survival, yet there is limited understanding of how we can target CPR to internal physiological markers. Our systematic review identified a paucity of studies evaluating whether hemodynamic-directed CPR can improve patient outcomes relative to current standardized CPR protocols. We also focused on the most widely available physiological monitoring tool in resuscitation, end-tidal carbon dioxide (ETCO2), and identified a high frequency of analytical error impeding accurate measurement. We developed and evaluated novel technology capable of reducing this error, resulting in a significant improvement in accuracy. Future research should be aimed at employing the refined algorithm for measuring ETCO2 capnography to identify prognostic trends, and develop therapeutic targets that can guide care in cardiac arrest patients.
Electrospray In Crossflow
Keywords: Crossflow
Electrified Jet
Electrospray
Mass Spectrometry

Characteristics of an electrospray ion source in an air crossflow is investigated. The effect of crossflow on the Taylor cone, the emitting jet, and the plume spray trajectory, are studied experimentally. The trajectory of a plume in the cone jet mode is related to the crossflow velocity, applied voltage to the nozzle, and the location of the ion source inside a dissovation chamber. An analytical model is developed for the prediction of the trajectory of an electrified jet in an electric field and a crossflow. A numerical solution is developed in order to simulate the traveling paths of single droplets inside the chamber, which is used to estimate the plume trajectory. The results of both models are discussed and compared with the experimental cases.
Identifying Dietary Fibre and Protein Intakes and their Food Sources in a Pre-dialysis Adult Population
Keywords: chronic kidney disease
dietary fibre intake
dietary protein intake
pre-dialysis
uremia

Background: Higher fibre intakes are associated with decreased chronic kidney disease (CKD) progression and cardiovascular disease (CVD) risk. However, knowledge is limited on the fibre intakes and dietary meal patterns in pre-dialysis. Objective: To describe the intakes of fibre and protein, and their food sources, in pre-dialysis patients and compare intakes to a healthy population. Methods: A cross-sectional, observational study, using the multiple-pass method repeat 24 hour recalls from 76 pre-dialysis CKD patients and data extracted from the Canadian Community Health Survey (CCHS). Results: The mean fibre intake of CKD patients was 17.6 (+ 10.3g/d), with 71% consuming
Older Adults' Acceptance of Virtual Doctors: A Preliminary Investigation
Keywords: Embodied Interaction
Empirical study that tells us about how people use a system
Health - Wellbeing
Human-Computer Interaction
Older Adults
User Experience Design

The use of virtual doctors is increasing; yet, we have not fully studied their impact and how they are perceived by the public, especially by digitally-marginalized users such as older adults. We also do not know how virtual doctors compare to other technology-mediated alternatives, like traditional telemedicine. More broadly, the factors leading to older users’ adoption of virtual doctors are not well understood. In other similar fields, users’ perceptions of early generations of conversational interfaces have been extensively studied. This raises the question of how virtual agents’ fidelity (e.g. video vs. speech-only) and agency (e.g. human vs. machine) influence confidence, comfort, and ease of use in target groups like older adults. To fill these knowledge gaps, I have conducted a mixed-methods study with older adults in which they engaged with different versions of telemedicine setups. The versions varied along the dimensions of fidelity (e.g. video vs. speech-only) and agency (e.g. human vs. machine). Analysis of interview and survey data shows that older adults were most confident and comfortable with speech-only machine-powered interfaces for general healthcare information, and with video-based link with human doctors for specific healthcare information. The findings also show that in order for virtual doctor systems to be accepted by older adults, they need to do the following: complement older adults’ visits to their existing doctors, fit their existing information practices for gathering healthcare information, and have perceived value compared to their currently available alternatives.
Effect of the Seasonal Changes in Fuel Composition on Particulate Matter Emissions from a Gasoline Direct Injection Engine
Keywords: Black Carbon
Gasoline Direct Injection Engine
organic Carbon
Particulate Emissions

The Ministry of Environment and Climate Change (MOECC) found that black carbons (BC) concentrations were significantly higher in summer than in winter, which could be attributed to the seasonal variations in fuel composition. This experimental study investigated the impact of fuel seasonal changes on particulate matter (PM) emissions using a Ford Focus wall-guided GDI engine. Fuels from five public gas stations having octane rating of 87 and 91 were analyzed and tested. This study demonstrated that summer fuels contained higher aromatics than winter fuels which led to higher PM emissions and BC concentrations during steady state and transient state conditions. Moreover, the removal of ethanol content resulted in lower PM emissions and BC concentrations during steady state conditions. This study suggested that an increase in aromatics in summer fuels could be root cause for higher BC concentrations, however, similar study should be performed in other engines to support this conclusion.
Morphology, crystallization, and mechanical property study of polypropylene and polyethylene terephthalate
Keywords: crystallization
in situ fibrillation
nanofiber
pet
polymer
polypropylene

This project covers a complete in-depth study of crystallization behavior of PP and in-situ fibrillated PET composites. Two kinds of PET, APET and CPET, were examined. SEM and DSC experiments were carried out to exam fiber morphology and crystallization kinetics. PET nanofiber was manufactured through a scalable melt spinning technology, and around 250 nm PET fiber was obtained. Isothermal and non-isothermal DSC experiments were performed. With the presence of PET nanofiber, dramatic improvement of PP’s crystallization kinetics was observed. Both Avrami and Mo’s method indicated the crystallization complexity and crystallization rate were increased. Reprocessing of fibrillated material into pellet showed moderate setback effect in PET’s promotional effect in PP crystallization. Also, the mechanical property was measured to show the influence of changed crystal structure. Increase in both the modulus and strength of the composites was observed.
Reducing Bias in Lidar-Only Motion Estimation
Keywords: Lidar
Mobile robotics
Odometry
SLAM
State estimation

Lidar sensors are used extensively in mobile robotics applications. As a moving-while-scanning sensor, motion estimation from lidar alone is challenging since the point-clouds measured are motion distorted. We develop a continuous-time lidar odometry pipeline based on the simultaneous trajectory estimation and mapping (STEAM) framework. Though accurate, there are biases in the estimator causing the odometry to drift over time. This thesis presents two approaches for bias reduction. First, a learning-based approach is developed, which trains a model using prior data. The model takes in point-cloud information and outputs the predicted biases. The predicted biases are then applied as a correction to improve the odometry. Next, we show that a source of estimator bias occurs when the motion model cannot sufficiently represent the underlying trajectory. We derive a novel white-noise-on-jerk motion model, and show that it outperforms the white-noise-on-acceleration motion model in the existing STEAM framework.
Radio Resource Management and Transmission Modes for Two-Tier Cellular Systems
Keywords: Cellular
Coverage
Heterogeneous
Networks
Two-Tier
Wireless

This thesis explores the paradigm of two-tier connectivity, in which secondary nodes utilizing wireless backhauling facilitate the connectivity of system users to base stations in a macro cellular communication setup. When compared to smaller cells utilizing wired backhauling to offload user traffic from macro base stations in conventional heterogeneous network approaches, secondary nodes of two-tier systems offer increased placement flexibility to connect user clusters, which is shown to be instrumental for maximizing densification gains and improving the performance of cell edge users. Depending on user distribution, utilized frequency bands and the capabilities of secondary nodes, up to 179% gains in the average and cell edge throughput rates are observed when augmenting macro cellular communication systems with secondary nodes.
Using Phase-Change Droplets for Indicator Dilution Measurements of Hepatic Perfusion Index
Keywords: Contrast Enhanced
Droplets
Hepatic Metastases
Hepatic Perfusion
Microbubbles
Ultrasound

There is a need to determine the extent to which areas within the liver are supplied by blood from the hepatic compared relative to blood from the portal vein, as this may provide a method to earlier detect tumours. Measuring this ratio in practice, however, has proven to be difficult. This thesis presents a method to separate the phases of liver enhancement using contrast enhanced ultrasound by vaporizing phase-change nanodroplets to locally create microbubbles. Droplets vaporized during the arterial phase produce contrast enhancement from the hepatic artery only. A following vaporization at a later point in time will produce bubbles in both the hepatic artery and the portal vein. By subtraction, the enhancement pattern resulting from the hepatic portal vein may be determined. The relative flow rate may then be calculated using indicator dilution methods. This method is validated by in vitro experiments.
Adsorption of Organic Pollutants from Oil Sands Process-affected Water Using NaOH-activated Delayed Coke
Keywords: acid-extractable organics
activated carbon
delayed coke
naphthenic acids
oil sands process-affected water
petroleum coke

Adopting the strategy of treating waste with waste, NaOH-activated delayed coke (ADC) was explored as an adsorbent for removing total dissolved organics (TOC) from oil sands process-affected water (OSPW). NaOH activation enlarged specific surface area and improved adsorption capacity of ADC for methylene blue (MB) by nearly 1000 times, from 0.24 mg/g to 228 mg/g. The affinity of TOC towards carbon is weaker than that of MB. The highest TOC adsorption capacity is 44 mg/g, recorded with ADC at pH 4 and 16 ℃. The equilibrium adsorption isotherms of both TOC and MB follow the Freundlich model. Although both are likely physisorption, TOC displays some behavior of cooperative adsorption that could result in multilayer adsorption at high TOC concentrations. Kinetic data of ADC for MB and TOC fit the pseudo-2nd-order model with high R2. The intraparticle diffusion was found to be the rate-limiting step in both MB and TOC adsorption with ADC.
Staying in Time: Does the Temporal Proximity of Related Events Drive Memory Integration?
Keywords: Cognition
Hippocampus
Learning
Memory
Psychology
Spatial

Flexible behaviour relies on our capacity to effectively use information gathered over the aggregate of our experiences. This requires memory to go beyond the act of simply recalling individual events; instead, it must be sensitive to relationships connecting our experiences. Prominent theories argue that this is possible through the formation of interconnected memory structures in the brain, whereby related experiences become integrated into overlapping neural populations. However, the conditions required for such integration are still not well understood. Emerging evidence suggests that the temporal proximity of two related events may influence how their content is integrated into memory. I first develop a training procedure for creating robust memories over short and long delay periods, and between distinct environments. Next, I evaluate participants’ tendency to integrate memory learned across related experiences separated by short and long delay periods. Together, these lay the foundation for investigating integration time windows in humans.
The Influence of Fluorinated Divinyl Urethane Monomers and Fluorinated Fillers on Resin Composite Physical Properties and Chemical Biostability
Keywords: biodegradation
composites
dental materials
dimethacrylates
fluorinated monomers
plasticization

Background: Salivary enzymes contribute to loss of resin composite material integrity and release of degradation products, suggesting that improving composite physical and chemical stability is required. Objectives: To study fluorine/urethane incorporation into resin composites and assess their influence on enzyme-mediated ester hydrolysis and mechanical strength. Methods: Fluorinated monomers and silanated barium borosilicate fillers were prepared and characterized by 1H-NMR [monomers] and thermogravimetric analysis (TGA)/X-ray photoelectron spectroscopy (XPS) [fillers], respectively. Composite formulations were assessed for mechanical strength, hydrophobicity, and biodegradation resistance using simulated human salivary esterase incubation conditions and ultra-high-performance liquid chromatography. Results: Eight different fluoro-monomers were assessed after incorporation into resin formulations at 35-55wt%. The best performing monomer was used alongside a fluoro/methacrylate silane and showed comparable mechanical/hydrophobicity properties but lower biostability relative to the control. Increasing the fluoro-contribution showed an optimum between reduced physical properties and improved biostability. Conclusions: Novel monomers should seek to remove/replace all vulnerable ester-containing monomers.
Current Ultrasound Technology for Guiding Intraoral Inferior Alveolar Nerve Blockade: A Feasibility Study
Keywords: inferior alveolar nerve blockade
local anaesthesia
sonography
ultrasound

In this multi-phase, randomized split-mouth study, a total of 80 volunteers received two different inferior alveolar (IAN) blocks: one side using a traditional landmarking technique and the other side an ultrasound (US)-guided technique. We also studied different US-guided approaches when the original approach was found to be unsuccessful. We used a visual analogue scale to evaluate pain caused by the US probe and by the different injection techniques. An electrical pulp test device was used to evaluate onset and success of the two techniques. In-plane US-guided nerve blockade was not technically feasible given the required position of the US transducer needed to appropriately visualize the IAN. US-guided with out-of-plane technique does not improve IAN block success rate. There was more pain associated with free-hand out-of-plane US-guided approach compared to a landmarked technique. There were no adverse events noted with any of the techniques or approaches.
Investigating the Impact of Long-Known Music Exposure on Brain Activity in Cognitively Impaired Older Adults
Keywords: Alzheimer's disease
Brain Plasticity
Intervention
Mild Cognitive Impairment
Music
Music Based Intervention

There is interest in developing preventative measures to mediate the manifestation AD in persons at risk for the disease. This study utilized a structured music-listening intervention to long-known, autobiographically salient music in older adults with cognitive impairment, where participants listened to long-known music for at least one hour per day for three weeks. A network involving frontal and limbic areas, as well areas involved in autobiographical memory, was preferentially activated during long-known music compared to recently-heard music. Post-intervention, our investigation revealed decreases in brain activity during music listening and statistically significant improvement in memory scores. These results are interpreted as improved neural efficiency associated with the implemented intervention. As a secondary analysis, it was revealed that non-musicians saw greater effect of intervention than musicians. These results provide preliminary evidence that long-known music listening intervention can induce brain plasticity to facilitate cognitive reserve to reduce risk of developing AD.
Memory and Network Interface Virtualization for Multi-Tenant Reconfigurable Compute Devices
Keywords: Cloud
FPGA
Memory
Networking
Reconfigurable
Virtualization

Field Programmable Gate Arrays (FPGAs) have increasingly been deployed in datacenters. These devices have proven effective at performing certain compute tasks better (faster, lower latency, higher throughput, and/or more efficiently) than traditional compute devices. In this work, we explore the application of the virtualization concept to multi-tenant FPGAs, with a specific focus on enabling multiple applications to securely share an FPGA and preventing snooping and/or errant behaviour. Conceptually, the traditional shell concept in FPGA design is extended to the hard shell and soft shell components. The hard shell focuses on the logical isolation of hardware applications on the same FPGA. For memory and networking interfaces on the FPGA, this work introduces hardware components aimed at enabling this isolation. In particular, the design of a new component that is termed the Network Management Unit (NMU) is presented in detail. The NMU enables the isolation of network traffic.
Sex differences in neutrophil extracellular trap formation
Keywords: Infection
Inflammation
Neutrophil
Neutrophil extracellular trap
Sex
Sex hormone

Immune responses vary between men and women. The female sex is considered protective in combatting acute infections, but disadvantageous in chronic inflammatory diseases. As neutrophils play a central role in innate immunity, they may mediate the sexual dimorphism in immune responses. Neutrophils can combat invading microbes by forming neutrophil extracellular traps (NETs). We hypothesize that females release higher amounts of NETs, leading to more robust acute immune responses. To test our hypothesis, neutrophils isolated from healthy human males and females were induced to form NETs in response to various pharmacological and biological stimuli. Total DNA content was higher in neutrophils from females compared to males. Female neutrophils released decreased levels of DNA in response to the calcium ionophore A23187. PMA, LPS, ionomycin and bacteria stimulation did not result in significant sex differences. Correlating the serum levels of the sex hormones testosterone, estradiol and progesterone to NETosis levels in the above conditions revealed a negative correlation between testosterone and A23187-mediated DNA release. No correlation was detected in relation to endogenous estradiol and progesterone levels, but a combination effect has not been fully explored. Exogenous estradiol or progesterone treatment at physiological concentrations did not influence DNA release. Given the results thus far, a sex difference in NETosis was detected with A23187 treatment but not from biological stimuli in the context of healthy neutrophils.
Plasma Membrane Recruitment Patterns of Glucose Transporters (GLUT) 1, 2, 3, and 5 in Response to Feeding in the Ruby-throated Hummingbird, Archilochus colubris.
Keywords: Feeding
Glucose transporters (GLUTs)
Hummingbird
Liver
Muscle
Sugar

Hummingbirds, among the smallest vertebrate endotherms, have high resting and active metabolic rates and subsist almost exclusively on nectar sugar; they face extreme challenges to energy homeostasis and blood sugar regulation. Transmembrane sugar transport, and thus some control over energy flux, is mediated by facilitative glucose transporters, GLUTs. I determined relative protein abundance and subcellular localization via Western Blot for several GLUTs in flight muscle and liver from fed or fasted ruby-throated hummingbird (Archilochus colubris). I observed GLUT5 protein in flight muscle PM, consistent with its hypothesized uniquely high flux of fructose. GLUT1 protein was absent in hepatocytes, contradicting previously observations of transcript. Finally, glucose-specific GLUT1 abundance was increased in flight muscle PM of fed birds, while liver PM was increased in GLUT3 and glucose/fructose-transporting GLUT2. This suggests muscle glucose uptake capacity is dynamically regulated in response to feeding, while both glucose- and fructose-uptake capacity respond in the liver.