VictorJuiz/thesis huggingface dataset:
In-situ Nano Fibrillation of Polyethylene Terephthalate (PET) in Polypropylene (PP) through Spunbond Process
Keywords: Die swell
In-situ
Morphology
Nanofibrillar composites
Spunbond
Visualization

Though the nanofibrillar composites (NFCs) concept has been developed more than a decade ago, the applied feasibility of NFCs in industrial scale has not been assessed yet. The present thesis contemplates the manufacturing process of NFCs specifically fibrillization step by designing and using industrial scale Spunbond Spinning System from two semi crystalline polymers Polypropylene (PP) and Polyethylene Terephthalate (PET). The PET domain adopts fibrillar structure as low as 40 nm with an average size of 92 nm. The research further develops the fundamental understanding of nanofiber formation by evaluating morphological study through employing SEM and polarized microscopy, thermal and viscoelastic properties by differential scanning calorimetry and rheological characterization method. In-situ visualization technique was utilized at the die exit to observe the matrix fiber formation and the well-known die swell phenomenon. Result shows that the final in-situ nanofibril size directly depends on the die swell and processing parameters such as airspeed and polymer flowrate.
Deciphering the Dialogue between the GTPase Cycle, Metal Binding, and Quaternary Structure of Escherichia coli HypB
Keywords: HypB
metalloprotein
nickel homeostasis
[NiFe]-hydrogenase

During the maturation of the bimetallic catalytic centre of [NiFe]-hydrogenase enzymes, the nickel insertion step is facilitated by the metallochaperones HypB and HypA. However, many of the underlying mechanisms behind the process of selective metal transfer from HypB to HypA are still unclear. To better understand these mechanisms, single-residue mutations were engineered into the metal-binding site of HypB. Experiments with C198T HypB revealed that C198 likely does not serve as a link between metal binding and GTP hydrolysis activity. However, complex formation between C198T HypB and HypA is impacted. Complex formation – and the transfer of Ni(II) – between F202A HypB and HypA has also been disrupted. These results demonstrate the importance of the HypB-HypA complex interface during selective nickel transfer from HypB to HypA, and suggest that there is allosteric regulation of complex formation, driven by communication from the metal coordination environment of HypB to the HypB-HypA complex interface.
The Experiences of Fathers in a Family Integrated Care (FICare) Program
Keywords: Experience
Fathers
Intervention
Neonatal Intensive Care Unit
preterm

OBJECTIVE: To describe the experiences of fathers of infants born at 320/7 to 346/7 weeks’ gestational age admitted to a Level II neonatal intensive care unit (NICU) and enrolled in a randomized controlled trial evaluating the Alberta Family Integrated Care (FICare) program. METHODS: A descriptive phenomenology study using semi-structured interviews with 13 fathers and 24 father-written journal entries. FINDINGS: Fifteen themes were generated by triangulating data from interviews and journals: mental preparation, fear of the unknown, reassurance of medical care, level of communication, identifying the fathers role, parenting with supervision, effect of medical staff, effective communication, physical environment, perceived health of infant, balancing life, teamwork through adversity, preparing for discharge home, post-NICU medical care, and relationship to child. CONCLUSIONS: Fathers enrolled in the Alberta FICare program attributed their level of confidence and positive NICU experience that continued post-discharge to the attention and the care they received at the bedside.
Hybrid Organic-CQD Solar Cells Using a Near-IR-Absorbing Organic Bulk Heterojunction
Keywords: Colloidal Quantum Dots
Organic
Photovoltaics
Solution-processed
Tandem
Thin Film

Solar photovoltaics requires further progress in efficiency at lower cost. Colloidal quantum dots (CQDs) are one of many emerging technologies that has been researched in recent years that could play a role in the future of photovoltaics. In this thesis, I developed a new hybrid organic CQD solar cell that achieved a power conversion efficiency (PCE) of 13.98% for the champion device, a record for CQD PV. Charge collection issues at the organic-CQD interface were identified with a study of the spatial collection efficiency of the device and were overcome by introducing a thin buffer layer of CQDs doped with 1,2-ethanedithiol. The hybrid devices were also used as the back cell in a four-terminal tandem device along with a perovskite top cell which was able to achieve a PCE of 23.2% with help from the broad absorption from 700-1100 nm enabled by the hybrid structure.
The Successes and Challenges of Syrian Refugee Families in Canada: A Follow-Up Study
Keywords: Bilingual Development
Educational Development
Language and Literacy
Refugees
Wellbeing

This study provides a one year follow-up on the resettlement experiences of four Syrian refugee families living in Canada. More specifically, this study focuses on the language and literacy development of refugee children. Overall, a lack of development in English and Arabic proficiency was noted among refugee children. A closer analysis of the learning environments of refugee children demonstrated there was a lack of support available at home and in school.
Changing for You, for Me: Gratitude Promotes Autonomous Motivation to Make Partner-requested Changes
Keywords: autonomous motivation
gratitude
partner regulation
self-determination theory

Two studies examined the role of receiving gratitude in promoting motivation to make a partner-requested change. In a cross-sectional study (N = 486), receiving gratitude for change efforts from a romantic partner was associated with greater motivation to make partner-requested changes. This association was distinct from general gratitude received from a partner. Importantly, self-focused autonomous motives mediated this association in this study and a pre-registered experiment (N = 431), demonstrating that gratitude may promote change efforts by making these efforts feel personally motivated and pursued for their inherent value. In Study 2, imagining receiving gratitude (as compared to a control condition) was also associated with increased feelings of reward and gratitude indirectly promoted motivation to make partner requested changes first through increased feelings of personal reward and subsequently through increased self-focused autonomous motives underlying change efforts. These findings have important implications for how couples can foster successful partner changes.
Reducing Off-chip Memory Accesses in Deep Neural Network Accelerators
Keywords: Hardware Accelerator
Neural Network

The popularity of deep neural networks (DNNs) has led to widespread development of specialized hardware for accelerating their computations. Many designs employ a memory system that consists of an on-chip local memory in addition to the off-chip main memory. In this dissertation, I seek to improve the energy efficiency in DNN accelerators by reducing the off-chip memory accesses. In the first part, I present and evaluate the required on-chip memory capacity and off-chip data footprint of various configurations for the on-chip memory. For memory configurations where off-chip memory accesses are reduced to once per value, up to 14.3 MB of on-chip memory capacity is necessary. In the second part, I introduce a compression scheme that can be added to any DNN accelerator. It leverages the inherent bit sparsity in DNNs to compress the weight values. Doing so, the off-chip data footprint is reduced by 2.5x-7.6x across the DNNs studied.
Delayed Gratification: A Double-edged Sword? A Study on the Relationship between Delayed Gratification, Work-life Conflict and Career Burnout
Keywords: Career
Career Burnout
Career Psychology
Delayed Gratification
Vocational Psychology
Work-Life Balance

The present study empirically examines the overarching research question: what is the relationship between delayed gratification, work-life conflict and career burnout in a general adult working population? A sample of eighty-nine participants completed an online questionnaire. The results suggest a) a statistically nonsignificant relationship between delayed gratification and work-life conflict, b) a very weak, statistically significant, negative relationship between delayed gratification and burnout c) a moderate, statistically significant, positive relationship between work-life conflict and burnout. Theoretically, this research provides a rationale for delayed gratification based upon Super’s (1990) Life Span, Life Space Theory. In terms of workplace implications, the results highlight the importance of employers understanding work-life conflict and career burnout among their employees. In terms of personal implications, the results capture the significance of engaging in recovery activities to decrease work-life conflict and career burnout. Counselling implications include facilitating client self-understanding of role importance to cope with work-life conflict.
Nanomechanics and Tribology of Molybdenum-Disulphide Based Solid Lubricants for Space Applications
Keywords: Molybdenum Disulphide
Nanomechanics
Solid Lubricant
Tribofilm
Tribology
Wear

Molybdenum-disulphide solid lubricant coatings have an established history of use in space applications. However, limited understanding of their breakdown and failure mechanics has led to premature failure of several systems and missions. In the present study, high-resolution nanomechanical testing techniques are used to examine specific failure mechanics of both pure and co-deposited MoS2 coatings. Fundamental properties such as fracture and shear strength are determined in relation to the nanostructural characteristics of the coatings. It is found that purely nanocrystalline MoS2 shows impeded shearing within the structure compared to partially amorphous MoS2 which therefore increases the friction and wear rates. Furthermore, three state-of-the-art co-deposited coatings are tested under earth to low-earth-orbit specific environments. The newly developed prototype coating is found to outperform the best commercially available coatings under true application-specific conditions. This increased fundamental and application-specific understanding of MoS2 based coatings allows for precision tailoring of MoS2 coatings for reliable performance.
Assembly, Integration, and Testing of Earth Monitoring Microsatellites
Keywords: Aerosols
Assembly
Integration
Microsatellite
Satellite
Testing

It has become clear over the last century that aerosol emissions have had a major impact on the Earth's climate and energy balance. Ground and air based aerosol observation techniques have proven to be cumbersome and can only provide data over short periods of time. Satellites, and particularly microsatellites, can provide an accessible method of Earth observation capable of collecting data over large areas for long periods of time. For this reason, the Space Flight Laboratory at the University of Toronto has developed the Next-Generation Earth Monitoring and Observation - Aerosol Monitoring (NEMO-AM) and DMSat-1 spacecraft. This thesis will provide a high-level overview of the assembly, integration, and testing phase for these microsatellite missions. This includes descriptions of the author's contributions to unit-level acceptance testing, battery pack design and assembly, and spacecraft-level environmental testing. The testing and analysis completed by the author to accept the missions' main optical payload is also described.
Transcriptomic Signature of Radiation Response in Li-Fraumeni Syndrome
Keywords: Cancer
LFS
Li-Fraumeni Syndrome
Radiation
RNA
second malignancy

Li-Fraumeni Syndrome (LFS) is an inherited cancer predisposition disorder associated with a germline mutation in the TP53 tumour suppressor gene. Impaired p53, important in the DNA damage response, has been shown to increase risk of radiation-induced second malignancy (RISM) in LFS patients. We hypothesize that a transcriptomic signature of RISM risk in LFS can be established and used as a predictive tool. LFS patient skin-derived fibroblast cell lines were used to demonstrate transcriptomic differences in patients that developed a RISM relative to those with long-term disease-free survival (LTDFS) post-radiation therapy. Potential RISM signature genes identified were additionally screened for involvement in radiation response and tumorigenic priming. The interconnected Wnt and hedgehog signaling pathways encompassed many of the proposed genes. Development of a RISM signature in LFS has potential to optimize treatment for LFS patients including modification of initial treatment and post-radiation surveillance for those considered high risk of RISM.
The Development and Evaluation of a Tool to Assess Competence in Diabetic Wound Management
Keywords: Diabetic Wounds
Generalizability theory
Medical education
Psychometrics
Surgical education
Validity theory

Background: Diabetic foot wounds are the greatest cause of extremity amputation in Canada. These patients are encountered by physicians and trainees in all specialties. Few studies focus on how to teach and assess wound management. We aimed to develop and build validity evidence for an assessment of diabetic wound competence. Method: We organized our tool development and validation process using Kane’s framework. A nominal group process i was used to develop the tool items and simulation-based testing scenarios. We then built validity evidence for tool by assessing 74 clinician participants’ performance during the two scenarios. Reliability was evaluated using generalizability Theory. Results: Cronbach’s alpha was 0.953 for the tool. Test-retest reliability was– ICC=0.943. Pooled inter-rater reliability was and good for average measures ICC=0.827. Our generalizability coefficient was 0.871. Conclusion: The validity evidence suggests our tool can be used to assess novice clinicians’ competence in diabetic wound management during simulated cases.
Impaired Motor Cortical Facilitatory-inhibitory Circuit Interactions in Parkinson’s Disease
Keywords: Circuit interactions
Cortical excitability
Cortical facilitation
Cortical inhibition
Neurophysiology
Parkinson's disease

Motor cortical (M1) inhibition and facilitation can be studied with short-interval intracortical inhibition (SICI) and short-interval intracortical facilitation (SICF). These circuits as well as the sensorimotor measure short latency afferent inhibition (SAI) are altered in Parkinson’s disease (PD). The purpose of this study was to examine the interactions between these circuits in PD. Fifteen PD patients were studied in ON and OFF medication states, and were compared to 16 age-matched controls. A triple-stimulus transcranial magnetic stimulation paradigm was used to elicit a circuit of interest in the presence of another circuit. SICI facilitated SICF in controls and PD ON, but not PD OFF. Therefore, the facilitatory effect of SICI on SICF is not present in PD OFF, but is restored with dopaminergic medication. SAI and SICI inhibited each other in all groups. These results suggest impaired interaction between M1 facilitatory and inhibitory circuits is a pathophysiological feature of PD.
An Investigation of Benzene-degrading, Nitrate-reducing Bacterial Cultures: Strategies for Countering Nitrite Buildup and for Assaying Anaerobic Enzymatic Activation of the Benzene Ring
Keywords: Anaerobic benzene degradation
Enzyme assays
Nitrite inhibition

Benzene is a widely used precursor compound in the chemical industry. Benzene could enter the environment in a variety of ways, including oil spills, leakage from underground gasoline storage tanks, and gasoline combustion. Bacterial cultures have demonstrated the ability of degrading benzene under a variety of electron acceptor conditions, including methanogenic, sulfate-reducing, iron-reducing, and nitrate-reducing. Benzene degradation under nitrate-reducing conditions is among the most energetically favorable conditions, but is hampered by the buildup of nitrite, the product of nitrate reduction. In this work, successful strategies for countering nitrite buildup were developed. Such strategies would enable the cultivation of large quantities of benzene-degrading, nitrate-reducing cultures, which could be applied to both bioremediation and for research purposes. This work also began to investigate assay systems to attempt to demonstrate benzene carboxylation as the first step of benzene degradation under nitrate-reducing conditions.
Investigating the Functional Consequence of Pik3c2b Ablation in a Skeletal Muscle Model
Keywords: c2c12
glucose metabolism
lipid kinases
PIK3C2B
skeletal muscle
x-linked myotubular myopathy

Phosphoinositide 3-kinases (PI3Ks) and its three distinct classes are involved in a myriad of cellular processes, including: cell growth, survival and intracellular trafficking. The Class II PI3Ks remain one of the least studied classes of lipid kinases. There are three isoforms of class II kinases, PIK3C2α, PIK3C2β and PIK3C2γ. Our laboratory identified PIK3C2β as a modifier of X-linked myotubular myopathy (XLMTM) caused by mutations in MTM1. However, PIK3C2β’s role in muscle and the consequences PIK3C2β ablation has not been elucidated. To answer this question. I generated a skeletal-muscle specific PIK3C2β KO mouse and found lower fasting glucose levels and increased AKT activation in muscle in an age-dependent manner. Next, I created and characterized PIK3C2β KO C2C12 myoblasts and discovered increased surface GLUT4 levels upon insulin stimulation. These new insights into the consequences of PIK3C2β ablation represent an opportunity to develop novel therapeutic strategies in XLMTM and metabolic disorders.
Validity of the Verbal Intelligence Quotient as a Proxy for Language Ability
Keywords: Autism Spectrum Disorder
Language Assessment
Oral and Written Language Scales
Proxy for Language Ability
Verbal Intelligence Quotient

Autism Spectrum Disorder (ASD) is characterized by impairments in social communication and restricted interests and repetitive behaviors. Structural language deficits are commonly observed. Studies examining the neurobiology of these structural language deficits have reported conflicting findings. It is suspected that the choice of measure used to evaluate language, and in particular the use of the Verbal Intelligence Quotient (VIQ) from the Wechsler cognitive batteries, may be contributing to these inconsistencies. This thesis explored whether VIQs could be reliably used as a measure of language ability in ASD and typical development. In a large cohort of children and youth with ASD and typically developing peers, we showed that across diagnosis and sex, VIQ scores accounted for a small proportion of variance in language scores from the Oral and Written Language Scales, 2nd Edition. Therefore, VIQ is not a suitable measure of language ability in ASD and typical development.
Using a Knowledge Engineering Framework to Develop the Clinical Reasoning of a Hybrid Therapy System for Upper Extremity Rehabilitation after Stroke
Keywords: Functional Electrical Stimulation
Knowledge Engineering
Rehabilitation
Robotics
Stroke

This thesis presents preliminary studies in developing clinical reasoning capabilities for an autonomous, intelligent, post-stroke upper-extremity rehabilitation hybrid therapy system. The hybrid system combines functional electrical stimulation (FES) with robotics, which allows the hybrid system to monitor a patient's performance during therapy while using its clinical reasoning capabilities to intelligently decide when to intervene with FES during a therapy session so as to be most beneficial to the patient. A novel approach to develop the hybrid system's clinical reasoning capabilities is taken by applying a systematic Knowledge Engineering (KEG) framework to elicit tacit knowledge of four experienced physical and occupational therapists, and explicate it into a knowledge model. A prototype of the hybrid system is then demonstrated to three occupational therapists via a mock therapy session. The KEG framework generated a sufficient amount of knowledge for implementation in the hybrid system software, while therapists agreed with the FES control decisions.
Machine Learning for Topic Classification and Prediction on Twitter
Keywords: Information Retrieval
Machine Learning
Popularity Prediction
Social Media Analysis
Time Series Analysis
Topic Classification

The rise of social media networks such as Twitter presents us with a massively distributed portal of information covering every topic from social and political news to entertainment. However, this coverage of different topics coupled with the high rate of content generation on Twitter results in an overwhelming volume of content that makes it difficult to detect and retrieve information relevant to a specific topic. Access to efficient methods for retrieval and analysis of this topical content can be of great value in a lot of different domains from social sciences to marketing analysis. Hence, the concept of learning topical classifiers and predictors for Twitter has become an important area of research. This thesis aims to address the challenges of topical content retrieval and analysis via efficient ways that will allow users to have real-time access to insights on their desired topics.
3D Dental Subsurface Imaging Using Enhanced Truncated Correlation-Photothermal Coherence Tomography
Keywords: 3D Imaging
Dental Imaging
Non-Destructive Testing
Optical Imaging
Photothermal Effect
Preventive Dentistry

With dental caries being the most common disease in human, development of accurate and sensitive dental imaging technologies for early caries detection and routine monitoring are crucial for preventive dentistry. However, radiographic technologies fall short of these objectives due to low sensitivity for small lesions and use of ionizing radiation. Here, dental enhanced Truncated Correlation-Photothermal Coherence Tomography (eTC-PCT) is presented as the first 3D tomographic thermophotonic dental imaging modality capable of monitoring and characterizing tooth demineralization with high sensitivity and without ionizing radiation. To this end, eTC-PCT is applied to teeth with natural defects, and artificially generated controlled early caries and surface erosion. Additionally, eTC-PCT performance for dental imaging is compared with other thermophotonic technologies. The results demonstrate that, eTC-PCT is capable of detecting and monitoring early demineralization in teeth at clinically applicable laser power levels, and visualizing the relative progression and extent of lesions through 3D reconstruction.
Clogging and Maintenance of Permeable Interlocking Concrete Pavement
Keywords: clogging
maintenance
permeable pavement
PICP

This research evaluates five of the different maintenance techniques to restore surface infiltration rate for permeable interlocking concrete pavements: (1) specialized maintenance equipment for permeable pavement; (2) pressure washing followed by manual vacuuming, (3) a regenerative air streetsweeper, (4) a vacuum streetsweeper and (5) a mechanical streetsweeper. A synthetic accelerated clogging method was developed to prepare the pavement for maintenance. Surface infiltration rates were measured throughout the clogging process and after the application of maintenance. Following the application of maintenance, joint penetration depths were also measured. The specialized equipment had the best performance, completely restoring of the pavement permeability. The vacuum sweeper had the best performance among the sweepers by restoring 80% of the pavement permeability. Results of this work will be used to develop best management practices for maintenance of permeable interlocking concrete pavements.