VictorJuiz/thesis huggingface dataset:
The Study on Cell Nucleation and Cell Growth Mechanisms and Behaviors in Multilayered Alternating Film/Foam Structures

This thesis presents the fundamental and experimental investigation of cell nucleation and growth mechanisms in advanced Micro-/Nano-Layered (MNL) polymeric structures with alternating film and foam layers. Novel strategies to optimize MNL structures are also developed. It is found that the final cell morphologies in MNL systems are governed by the synergy of two categories of parameters: morphological parameters, i.e., layer thicknesses and interface densities; and material parameters, i.e., material stiffness and material compatibility. The presence of adjacent film layers can significantly increase cell densities and decrease cell sizes through two mechanisms: promoting heterogeneous cell nucleation and preventing cell deterioration. Stiffer and more compatible film layers produced higher cell densities by further boosting these two mechanisms. Moreover, as a stiffness-enhancing strategy, the crystallization of PC layers was successfully achieved for the first time in MNL structures, resulting in more pronounced optimizations in cell morphologies.

Keywords: Material science
Multilayered structures
Polymer manufacturing
Advisor: Lee, Patrick C
Reimagining Informal Place-based Learning: An Exploration through Narratives of Scarborough Residents

Scarborough, a region marred by its representation as a “dangerous” region has arguably left residents with internalized otherness, along with complicated understandings of themselves and their surroundings. Using narrative inquiry, this qualitative study explores how Scarborough residents conceptualize informal learning in connection to place. Interviews were conducted with six residents from the Malvern and Kingston-Galloway/Orton Park (KGO) neighbourhoods to better understand their lived experiences and interactions with informal learning. Critical pedagogy of place and critical consciousness are the theories informing the conceptual framework and guiding this study. Emerging from the data are four themes: shared understandings of community, barriers to learning and opportunity, meaningful informal learning experiences and representative and reciprocal relationships. In using place as a guiding framework for inquiry, residents describe the creation of informal spaces of gathering and storytelling as tools in countering the hegemonic narratives of Scarborough and its many communities.

Keywords: adult education
educational leadership
informal learning
narrative inquiry
place-based learning
Scarborough
Advisor: McCready, Lance T
ApoE4 and the Clinical Outcomes and Pathophysiology of Degenerative Cervical Myelopathy: Evidence from Human Data and Mouse Models

Degenerative cervical myelopathy (DCM) is the most common cause of nontraumatic spinal cord injury in adults worldwide. Surgical decompression is considered the gold standard treatment for DCM, as it is effective in halting further myelopathy. Evidence shows a significant proportion of patients may experience neurological deterioration post-decompression, though the mechanisms underlying this is unknown. Genetic factors may contribute to this patient heterogeneity. Our study aimed to elucidate the influence of the apolipoprotein E4 (ApoE4) allele in the pathophysiology of DCM. We demonstrate that the ApoE4 allele induces an excessive pro-inflammatory response after decompression in a DCM mouse model, resulting in a delayed functional recovery. In human DCM patients, ApoE4 carriers have a significantly lower extent of improvement, or even deteriorate, following surgical decompression. Our study is the first to investigate the role of ApoE4 in DCM. These results may contribute to altering the standard of care for ApoE4+ DCM patients.

Keywords: Apolipoprotein E4
Decompression Surgery
Degenerative Cervical Myelopathy
Inflammation
Advisor: Fehlings, Michael G.
Large-scale Testing of Replaceable Cast Steel Links

Eccentrically braced frames (EBFs) have been widely used for their high stiffness obtained from the diagonal braces and high ductility obtained from the yielding links. Replaceable cast steel links were developed to take advantage of the inherent geometric freedom of steel casting and to avoid common failure modes associated with rolled or built-up sections which limited the ductility capacity of the links.This thesis summarizes the experimental program of testing two replaceable cast steel links in a large-scale eccentrically braced frame test setup, loaded under quasi-static cyclic lateral displacements. The link specimens were tested with and without a composite slab to study the effect of the composite action under high axial loads. The links exhibited a stable cyclic ductile behaviour with the total link rotation reaching up to -0.19 rad and demonstrated that it can provide high overstrength factors of 2.07 in tension and 1.703 in compression.

Keywords: Cast steel
Eccentrically braced frames
Large-scale testing
Steel frames
Advisor: Kwon, Oh-Sung
Christopoulos, Constantin
Conductive Composites for Use in Sensing Applications

Polymers have a wide array of applications owing to their limitless tailorable properties. The inherent non-conductivity of polymers limits their use in electrical applications. By combining with conductive fillers, an entirely new dimension of possibilities can be explored in biomedical, human health monitoring, sensors, wearable electronics, and various other applications. This thesis studies the functionality of conductive polymers in a few selected fields such as electrocardiogram devices, smart textiles, contaminants, and strain sensors. Study 1 revealed that different polymers have vastly different electrical performance, especially in electrocardiograms even if filler content remained the same. Study 2 showed how conductive textiles can be used in human health monitoring and assist in long term care facilities. Study 3 demonstrated the capabilities of conductive nanocomposites as a contaminant and strain sensor using a unique electroplating coating method of electrospun fibers. The research into these smart materials is a continuously developing and emerging field.

Keywords: Carbon Nanotubes
Polymer Composites
Sensors
Wearable Technologies
Advisor: Naguib, Hani E.
Teachers’ Beliefs about Assessment: A Multiple Narrative Case Study of Internationally Educated Teachers’ Assessment of Speaking Skills in Canadian ESL/EAP Classrooms

This multiple narrative case study examines the assessment beliefs of internationally educated teachers in assessing speaking skills in Canadian ESL/EAP classrooms. Research highlights how teachers’ assessment beliefs influence the way they conceptualize assessment purposes and integrate them into curriculum and lesson planning. With the increasing number of internationally educated English language teachers working in various K-12 and post-secondary contexts in Canada, it is important to understand how their previous assessment beliefs and practices impact their assessment in a new teaching context. The study revealed IETs held multi-layered beliefs focused on the purpose of assessment, types of and tools for speaking assessment, and feedback. Also, numerous contextual factors including classroom contexts, institutional requirements, and curriculum expectations seem to contribute to their change in speaking assessment practices in varied contexts. The results implicate IETs as a heterogeneous group of professionals who require differentiated professional development opportunities and mentorship programs to better integrate in Canadian ESL/EAP classrooms.

Keywords: Assessing Speaking Skills
ESL/ EAP Classrooms
Internationally Educated Teachers
Techer Beliefs
Advisor: Labrie, Normand
In-service Skill Development on Queer and Trans Identities and Literacy Practices for Ontario French as a Second Language Professionals

French teachers are under significant and unique pressures to address gaps in curriculum and practice with regard to Two Spirit, queer, and trans students.Though a helpful tool, Miller’s (2015) queer literacy framework (QLF) has not been considered in published research in French as a second language (FSL) classrooms. In this study, I draw on sociocultural theory to offer professional development to FSL professionals regarding the QLF. The findings confirm a fear of consequences for integrating queerness into teaching. Additionally, the instruction of grammar is understood to be a vehicle for (safely) bringing queerness to the FSL classroom. It also shows how mediation was and was not possible in a digital environment. Finally, it suggests the importance of examining teacher beliefs and practices in professional development. Further work is required to confirm theorizing on the relationship between grammar and social justice and what more is required to integrate the QLF into FSL practice.

Keywords: French as a Second Language
Professional Development
Queer
Teacher Development
Advisor: Bale, Jeff
Investigating the Mechanism of Allosteric Regulation of HpNikR by pH and Nickel

Nickel ions are essential for the survival of Helicobacter pylori in the acidic human stomach. H. pylori NikR (HpNikR) is a nickel-responsive transcription factor that regulates the expression of many genes involved in nickel homeostasis. HpNikR also assists in acid adaptation by binding to DNA independent of nickel in response to increased acidity. It is unclear how nickel or increased acidity promote HpNikR DNA binding. The goal of this study was to determine a mechanism of allosteric regulation of HpNikR by nickel and pH. Several networks connecting proteomic sites to the DNA-binding domains were investigated. Nickel-activated DNA-binding was found to involve a cation- interaction at the N- and C-terminal domains. 19F NMR revealed that increased acidity slows HpNikR conformational exchange in the presence of DNA. Finally, it was found that residues essential for nickel-activated DNA binding are also important for DNA binding in acidic solutions.

Keywords: Allostery
Helicobacter pylori
HpNikR
Metalloprotein
Nickel
Advisor: Zamble, Deborah B
Kluger, Ronald H
Studies of Photochemistry in Some Indoor and Outdoor Environments

The impacts of photochemistry can be observed in our everyday lives. This thesis explores two small portions of this daily importance, by highlighting its impact on tracking our oceans’ primary productivity, and the air we breathe inside our homes. Chlorophyll fluorescence can be correlated to phytoplankton in our oceans. We look at chlorophyll, to examine the fluorescence quenching rate constants of common seawater components such as halides (Cl-,Br-,I-) and Iron(III). We do this by comparing spectra which show fluorescence intensity of pure chlorophyll in comparison to this same solution’s fluorescence in the presence of sea water quenchers. In a second study, we show that paints specifically marketed to be photoactive can produce NOx compounds such as (NO,NO2,HONO) from the aqueous deposition of nitrate (NO3-) and gas (NO) phase at 0 and 50 % RH, under illumination sources found indoors (fluorescent ,xenon, incandescent). These gaseous species can be important sources of indoor ozone and OH, which impact the oxidation capacity indoors

Advisor: Donaldson, D.James
Prostate Specific Antigen Dynamics and Prostate Cancer Risk: A Population-based Study

The objective was to determine the association between prostate specific antigen (PSA) predictors and prostate cancer diagnosis. This was a retrospective, unmatched nested case-control cohort study of men 40-75 years of age undergoing opportunistic PSA testing. PSA levels of patients diagnosed with prostate cancer were compared to patients who were not using logistic regression. Overall, 508,238 patients were included (12,444 cases and 495,794 controls) over a median 8.2 years (IQR: 7.0-9.1). First PSA, final PSA, and percentage change in PSA per 365 days were highly predictive of prostate cancer. The final multivariable model preformed well when predicting prostate cancer and clinically significant prostate cancer diagnosis. Together, the identified variables can be used to better select those who should undergo prostate biopsy. Due to inherit selection and verification bias, prospective validation studies are needed. Further studies are needed to determine the association with metastatic and lethal prostate cancer.

Keywords: baseline prostate-specific antigen
prostate cancer
prostate-specific antigen
prostatic neoplasms
risk assessment
Advisor: Nam, Robert K
Online Continual Learning in Image Classification

Online continual learning (CL) in image classification studies the problem of learning to classify images from an online stream of data and tasks, where tasks may include data with new classes or nonstationarity. This thesis starts with a comparative empirical survey of the state-of-the-art methods and recently proposed tricks to better understand their relative advantages and the settings where they work the best. To prepare CL for real-world applications, we provide a simple but effective approach that combines memory replay, CL tricks summarized in the survey and common image classification techniques. Moreover, for replay-based approaches, we propose a novel Adversarial Shapley value scoring method for memory sample selection that scores samples according to their abilities to preserve latent decision boundaries for previously observed classes while interfering with latent decision boundaries of current classes being learned. Our proposed method shows state-of-the-art performance, especially when the memory buffer size is small.

Keywords: Catastrophic Forgetting
Continual Learning
Incremental Learning
Lifelong Learning
Online Learning
Advisor: Sanner, Scott
Deformations in Flexure-critical Reinforced Concrete Members

The need to understand complex structural behaviour presents an opportunity to enhance modelling and design practices. Reinforced concrete is ubiquitous in our infrastructure; however, post-yielding deformation behaviour of reinforced concrete is not well understood. Post-yielding displacements are not used in traditional strength-based design, which focuses on providing adequate strength. A popular concept for seismic applications relies on accurately predicting the post-yielding deformations of elements. To implement such strategies requires further knowledge on how reinforced concrete members deform after yielding. The experimental program focused on measuring the components of deformation of a set of twelve reinforced concrete members. In these tests the reinforcement ratio and overall member depth were varied. The results support that shear strains play a significant role in predicting a member’s overall displacement, as well as the shape of the deformed member. It is recommended that these results be used in the development and calibration of numerical analyses.

Keywords: Concrete
Deformation
Displacement
Flexure
Advisor: Bentz, Evan C
Assessment of Ultrafiltration Membrane Ageing in Full-scale Water Treatment Facilities

The incorporation of ultrafiltration has become increasingly prevalent in drinking water treatment. However, limited data exists regarding the impacts of membrane ageing over extended periods of full-scale operation. The present study examined performance factors (clean membrane resistance, fouling rate, and susceptibility to breach), as well as characteristics (presence of hydrophilic additive (HA) present in membranes) for polyvinylidene fluoride membranes that are widely employed. Clean membrane resistance remained constant over time, whereas the fouling rate decreased with age. Surface and bulk HA content were observed to decrease with age. However, poor correlations were observed between HA content and clean membrane resistance. Results suggest that although a reduction of HA occurs as membranes age, membranes continued to provide good treatment performance until they reached a certain level of HA content reduction that was site-specific. Overall, these findings provide important insights regarding the mechanisms associated with membrane ageing.

Keywords: Membrane Ageing
Ultrafiltration
Advisor: Andrews, Robert C
Bérubé, Pierre
Deuterium Magnetic Resonance Spectroscopy of Early Treatment-induced Changes in Tumour Lactate

An emerging hallmark of many tumour cells is aberrant metabolism, characterized in part by elevated lactate production. In response to treatment, tumour cells exhibit a change in lactate production that precedes late-stage morphological measurements conventionally used to assess tumour response. These metabolic changes can be non-invasively measured by Deuterium (2H) Magnetic Resonance Spectroscopy (MRS), but there has been limited work exploring the feasibility of using 2H-lactate as a marker of early tumour response to treatment. In this thesis, the biological processes associated with treatment-induced changes in the 2H-lactate signal were established in an in vitro tumour model. Significant decreases in 2H-lactate were observed 48 hours after treatment with a chemotherapeutic agent and associated with apoptotic cell death and decreased extracellular lactate. These findings offer the opportunity to build a framework for preclinical 2H MRS studies of tumour metabolism, with the goal of enhancing assessment of tumour response in the clinic.

Keywords: cancer
deuterium magnetic resonance spectroscopy
metabolic imaging
treatment response
tumour lactate
warburg effect
Advisor: Lau, Angus Z
The Role of BMAL1 in Linking the Molecular Clock and Circadian Rhythm of Cerebral Myogenic Tone

Cerebral arteries show a circadian rhythm in myogenic reactivity, the intrinsic ability of resistance arteries to adapt their tone to fluctuations in transmural pressure. The expression of cystic fibrosis transmembrane conductance regulator (CFTR), a known negative regulator of myogenic signalling in cerebral artery vascular smooth muscle cells (VSMCs), demonstrates cyclic behaviour in phase with other known circadian genes. I demonstrate that the known peak and trough of the CFTR protein expression rhythm are disrupted by abolishment of the peripheral molecular clock, induced by smooth muscle-specific deletion of Bmal1. A disruption to CFTR oscillations directly induced by peripheral clock dysfunction strengthens the hypothesis that CFTR is the site of circadian regulation of cerebral myogenic reactivity.

Keywords: BMAL1
Cerebral
CFTR
Circadian
Clock
Myogenic Tone
Advisor: Bolz, Steffen-Sebastian
Graphical Processing Unit 5G Primary Synchronization Signal Detection in Software Defined Radio

The Primary Synchronization Signal (PSS) is an important synchronization signal in 5G. It is the first signal the User Equipment (UE) detects during initial access and the handoff process. At this stage, symbol timing, a necessity for Orthogonal Frequency Division Multiplexing (OFDM) demodulation, is not present. Furthermore, the UE has no exact knowledge of where the Primary Synchronization Signal is or whether it is present, forcing the UE to process many samples to determine where the PSS is or if it is present or not. In a Software Defined Radio (SDR) system that is emulating the UE, the detection of the PSS falls to the Central Processing Unit (CPU) to perform and its processing time is longer than the rest of the synchronization process combined. For example, in the Eurecom Open AirInterface (OAI) SDR implementation, the initial synchronization process takes several seconds and most of it is spent on PSS synchronization. To address this, a Graphical Processing Unit (GPU) based implementation is proposed, with potential speed up of 100 times greater than CPU based implementation.

Keywords: CUDA
GPU
PSS
Advisor: Sousa, Elvino S
The Seismic Resilience of Critical Spatially-distributed Building Portfolios: A Case Study of Public School Buildings in Makati and Quezon City, Metro Manila, Philippines

This thesis presents an integrated seismic resilience framework that links advanced building-specific earthquake engineering techniques and portfolio risk methodologies for evaluating large building portfolios in a computationally efficient manner. The framework is applied to a spatially-distributed infrastructure portfolio composed of over 1,000 public school buildings across two cities.The near-fault seismic hazard of the region was defined using state-of-the-art tools. A rapid visual screening of approximately 200 buildings was conducted to enhance high- level inventories and inform the development of detailed non-linear structural models of the key archetypes. Building response simulations under a range of seismic intensities were coupled with the FEMAP-58 and Arup REDi Monte Carlo analyses, requiring the adaptation of existing post-earthquake consequence functions. Normalized archetypal vulnerabilities were developed and assigned to all the buildings before simulating portfolio losses under various seismogenic sources. The impacts of proposed portfolio-level mitigations strategies were then discussed.

Keywords: Earthquake
Engineering
PBEE
Resilience
Seismic
Structural
Advisor: Christopoulos, Constantin
Effect of Resin and Fatty Acids on Sodium Salt Scaling

The evaporation of black liquor is an important, energy intensive unit operation in the kraft chemical recovery process. Between 50 and 85% dry solids, black liquor evaporators are susceptible to heavy sodium salt scaling leading to reduced heat transfer efficiency. Recent mill experiences indicate that the addition of small amounts of resin and fatty acids (RFA) containing streams (tall oil soap, tall oil brine) to the concentrators can reduce sodium salt scaling. The underlying mechanism for this is unknown, which limits broader application and control. In this work we validate a gas chromatography mass spectrometry method for RFA determination and use model solutions of sodium salts in a bench-top scaling setup to investigate the impact of RFA on sodium salt scaling. The results show that low concentrations of abietic acid and oleic acid can inhibit sodium salt scaling during nucleation and in the presence of a stable crystal population.

Keywords: fatty acid
fouling
kraft black liquor
resin acid
sodium salt
Advisor: DeMartini, Nikolai
Cryogenic Device Characterization and Wideband Receiver Design for Large-scale Monolithic Quantum Processors

This thesis proposes a pathway to realizing large-scale quantum computing integrated circuits based on the monolithic integration of high-temperature (1–4 K) semiconductor qubits with their associated control and readout circuitry. High-frequency device characterization was performed on production 22-nm FDSOI technology at room and cryogenic temperatures (down to 3.3 K) to inform a cryogenic circuit design methodology in the absence of low-temperature device models. The methodology was demonstrated with a TIA qubit-readout chain that was, for the first time, monolithically integrated with electron and hole quantum dot structures. The prospects of FDSOI SiGe BiCMOS technology would enable similar integration with higher performance HBT devices. As a first step, design of a 240-GHz direct conversion I-Q receiver is showcased in 55-nm SiGe BiCMOS, intended for frequency-division multiplexed readout of many qubits. The measured IF-bandwidth of 59 GHz makes it suitable for high data-rate communication and large-scale quantum processors.

Keywords: cryogenic characterization
FDSOI
receiver
SiGe BiCMOS
spin qubits
variable-gain amplifier
Advisor: Voinigescu, Sorin