VictorJuiz/thesis huggingface dataset:
Development of a 96-well Platform for the Bulk Production of Three-Dimensional Human Skeletal Muscle Microtissues
Keywords: Drug testing
Skeletal muscle
Tissue engineering

Skeletal muscle wasting is a largely untreatable condition wherein patients lose skeletal muscle strength, stamina, and protein content. We posit that the lack of skeletal muscle wasting treatments is due to the failings of existing skeletal muscle models. To address this problem, we developed a human muscle microtissue (hMMT) platform for bulk generation of reproducible, contractile, 3D hMMTs. hMMTs recapitulated key aspects of native human skeletal muscle, including muscle-specific protein expression, drug response, and contractility. Furthermore, the hMMT platform can non-invasively assess strength, and is exceedingly simple to fabricate. To illustrate hMMT platform utility, hMMTs were used with tumour-conditioned media to model cancer-associated muscle wasting in vitro. hMMTs were also used to screen chemotherapeutics, revealing that the drug irinotecan is toxic to human myofibers. Collectively, these results underline the considerable potential of the hMMT platform as a vehicle for skeletal muscle research and drug candidate validation.
Monitoring Ice Phenology and Characteristics in Mid-latitudes using RADARSAT-2
Keywords: Central Ontario
Lake Ice Phenology
Lake Ice Thickness
RADARSAT-2
Remote Sensing

This study investigates the use of remote sensing for monitoring ice phenology and ice characteristics (ie. ice thickness). The primary data used were RADARSAT-2 images acquired over Central Ontario between 2008 and 2017. In order to monitor ice phenology, an automated threshold method was developed to identify freeze and melt events. During the 2015/2016 and 2016/2017 ice season 12 out of 17 identified freeze events and 13 out of 17 identified melt events were successfully validated. The radar determined dates were validated using in situ data, and visible remote sensing data. Temperature models and radar backscatter were used to estimate ice thickness in Central Ontario. The results of this analysis were validated using a combination of in situ measurements and data from a Shallow Water Ice Profiler (SWIP), correlation statistics for temperature models were >0.9 and an R2 of 0.6 was observed for backscatter models.
Dreissena Fouling Control for Water Treatment Plants and the Investigation of a New Copper-based Molluscicide
Keywords: copper
dreissena
Mussel
Quagga
Water Treatment
Zebra

Mussel macrofouling is a major concern for water treatment plants in the Great Lakes region, with the threat typically being controlled through seasonal pre-chlorination. Treatment facilities are now re-evaluating this strategy due to the transition from zebra mussels to cold-tolerant quagga mussels, infestations at certain facilities, and stricter disinfection by-product regulations. Two problems faced when looking for alternative strategies is limited mussel monitoring data to make decisions and the lack of alternatives to chlorination. This project addressed these deficiencies through the implementation of a series of plant-specific monitoring programs to quantify mussel infestation risks to re-evaluate seasonal treatment thresholds and to identify other fouling risks. In addition, a pilot scale study was undertaken to evaluate a new copper-based molluscicide called EarthTec QZ. The research also explored interactions of EarthTec QZ with downstream organics removal during coagulation, and with chlorination decay kinetics.
A Role for Adseverin in the Invasion and Migration of MCF7 Breast Adenocarcinoma Cells
Keywords: actin microfilament
adseverin
cancer migration and metastasis
morphology
remodeling

Adseverin (ADS) is a Ca2+--dependent, actin-capping and severing protein that is upregulated in multiple cancers. Increased Ca2+ promotes ADS-dependent severing of subcortical actin filaments, enabling modifications of cell shape, a requirement for cancer cell invasion of the matrix. Suppression of ADS expression reduces migration and proliferation of metastatic cancer cells. I hypothesized that ADS involvement in subcortical actin remodeling enables changes of cell shape, motility, and invasive potential through extracellular matrices. I examined the effects of ADS expression on cancer cells by generating a CRISPR-Cas9 knockout (KO) cell line. Morphological characteristics and invasive potential were examined. KO of ADS altered cell morphology as seen by reduced cell extension formation and degradation of collagen. Three dimensional migration, but not two dimensional migration was inhibited by KO of ADS. I conclude that ADS promotes the formation of invasive cell structure, cell migration and metastasis.
The Role of Interleukin-1 Beta in Mediating LPS-Induced Reverse Transendothelial Migration of Intimal Dendritic Cells
Keywords: Dendritic Cell
Interleukin-1 Beta
Intima
Lipopolysaccharide
Reverse Transendothelial Migration

Intimal dendritic-like cells (DCs) reside in regions of the aorta predisposed to atherosclerosis. LPS and interleukin-1 beta (IL-1β) injections into C57BL/6 mice result in decreased numbers of intimal DCs due to their exit into the blood via reverse transendothelial migration (RTM). This study evaluated the role of IL-1b in RTM induced by intravenous LPS injection. IL-1β mRNA expression was rapidly upregulated in the intima by LPS. Experiments using genetic approaches (Il1b-/-, Casp1-/- and Il1r1-/- mice) and function-blocking antibodies demonstrated a critical role for IL-1b production and signalling in LPS-induced RTM. Reciprocal bone marrow transplantation experiments revealed that IL-1β production and signalling only in the non- hematopoietic compartment, likely endothelium, was critical. Ex vivo studies showed that IL-1b could rescue RTM in the Il1b-/- aorta, implicating sustained intimal IL-1b signalling. These data suggest that intimal IL-1β production and signalling in endothelial cells is required for LPS- induced RTM of intimal DCs.
Effect of Pressure on Soot Morphology in Laminar Diffusion Flames
Keywords: Combustion
Flame
Fractal
Soot

The effect of pressure on soot aggregate morphology in laminar diffusion flames, specifically pertaining to primary soot particle size and soot aggregate fractal parameters, was investigated in methane-air and nitrogen-diluted ethylene flames. Soot aggregate samples were collected by thermophoretic sampling within a high-pressure combusting chamber. Soot samples were imaged via transmission electron microscopy followed by an automated imaging detection method. The experiments covered pressures from 7 to 30 bar at vertical flame heights of 3, 6, and 8 mm in methane-air flames, and 3 to 6 bar at heights of 2, 5, 10, and 15 mm in nitrogen-diluted ethylene flames. It was observed that mean primary soot particle size increased with increasing pressure for both fuel types at virtually all flame locations. The fractal dimension was found to vary with pressure for both fuel cases, suggesting that a universal soot aggregate fractal value may not be justified in high-pressure flames.
Development of TCR-engineered iNKT cells for Cancer Immunotherapy
Keywords: adoptive cell therapy
cancer
Immunotherapy
iNKT cells
innate immuninty
TCR-engineering

Invariant Natural Killer T (iNKT) cells are innate T cells that respond to lipid antigens presented by the molecule CD1d. Activated iNKT cells rapidly produce copious amounts of cytokines, activate/recruit other immune cells and have been implicated in tumour rejection and tumour immuno-surveillance. Here, our goal is to exploit iNKT cell antitumour properties in adoptive cell therapy and redirect their specificity towards tumour-associated antigens (TAAs) through T cell receptor (TCR) engineering. We hypothesize that TCR-engineered iNKT cells will be more effective than conventional CD8 T cells and provide long-term immunity.
A Cardiac Suspension Unit for Mitigating Thoracic Pressure in Postoperative Open-Sternal Newborns: A Heat Bed and X-Ray Compatible Design
Keywords: Cardiac Suspension
Delayed Sternal Closure
Multivariate Design
Neonates
Non-backdrivable
Tensioner

Background Newborns with heart defects require surgery where immediate chest closure may not be possible. Cardiac suspension applies chest-wall traction to mitigate complications but is limited by its unquantified tension, lack of X-ray compatibility, and aesthetic. A designed tensioner unit may resolve these challenges. Methods Design requirements are established by chart-review and surveying. Subsystems are evaluated though analytics, FEA, and experimentation. The device is assessed for rigidity, transmission, heat transfer and radiolucency. Results Patient data is presented, design requirements are established, and a cantilever design is selected. The framing achieves fixation but with slight deflection. A compensator and non-backdrivable input are developed for the wire system. Transmission friction losses are noted. EB beam modelling identifies Ultem for the cantilever design. Significance This research presents the first investigation into the cardiac suspension technique. A prototype was designed, built and tested, and is a strong step towards improving cardiac suspension.
Mapping Inequalities of Access to Employment and Quantifying Transport Poverty in Canadian Cities
Keywords: accessibility
inequalities
public transit
spatial analysis
transport poverty
urban systems

Millions of Canadians rely on public transportation to conduct daily activities and participate in the labour force. However, many are disadvantaged because existing public transit service does not provide sufficient access to destinations. Limited transit options, compounded with socioeconomic factors like not having a private vehicle, can result in transport poverty, limiting travel to important destinations, like employment opportunities. Accordingly, the objective of this thesis is to develop accurate measures of accessibility to examine the degree to which the Canadian urban population can reach employment opportunities via public transit. These measures are used to analyze inequalities in accessibility with respect to socioeconomic status and estimate where, and to what extent, Canadians are at risk of transport poverty. This knowledge is able to inform policy aimed to increase transit ridership, reduce inequalities of transit accessibility, and limit transport-related barriers to activity participation.
Holocene Perspectives on Hydrogen Isotope Ratios of Boreal Plant Waxes in Northwestern Canada
Keywords: Beringia
Holocene
n-Alkanoic acids
Net fractionation
Plant waxes
Stable hydrogen isotopes

This thesis provides novel insights into plant wax characteristics and fractionation in high latitude boreal forests in the Holocene. The isotopic composition of precipitation is a tracer for climatic changes. The hydrogen isotopic composition of plant waxes (δDwax) in sediments is a proxy for precipitation δD and paleoclimate but is offset from δDprecip due to a large net fractionation from several biotic and abiotic factors. The net fractionation is constrained for the northern boreal forest based on topsoils from a 13-site network in NW Canada. This will help future studies quantitatively reconstruct δDprecip from plant waxes. This thesis also presents the first δDwax record that extends through the full Holocene in Eastern Beringia from a lake sediment core in SW Yukon. Good coherence with other isotope proxies in the region suggests that this record accurately reconstructs variability in δDprecip and is likely driven by changes in atmospheric circulation and aridity.
An Ontario Primary Health Care System to Support a Cavity-Free Future
Keywords: Dental public health
Early childhood caries
Fluoride varnish
Prevention
Primary healthcare

Fluoride varnish (FV) is a proven intervention for preventing early childhood caries. Due to frequent contact with children, primary healthcare professionals may be ideally situated for FV application. Currently, public health units across Ontario are implementing FV in primary care. Yet challenges remain at the political, professional, and practice levels. This study aims to understand the perspectives of key stakeholders on making FV application routine primary care practice in Ontario. Our findings suggest that there is an opportunity for interdisciplinary care and motivation for this intervention. However, we found that concerns related to funding, oral health knowledge, and existing inter-professional relationships may impede implementation. With respect to introducing a dental intervention into medical practice, the many factors required to implement change may not be in alignment. However, representatives across all fields are motivated and have identified opportunities for change that may form the foundation for this program in the future.
The Geographic Imaginaries of Empire: Migration, Tourism, and Constructions of Difference in Panamanian Travel Narratives
Keywords: colonialism
imperialism
migration
Panama
tourism
travel

Panama’s tourism industry has flourished since 1990 to become one of the premiere travel destinations in Central America as described by tourism literature. Using historical geography as its methodology, this thesis offers an analysis of how colonial logics of empire remain embedded in the Panamanian tourism industry and nation building agendas. In particular, the discourse analysis of Panamanian travel narratives in archival and contemporary travel literature has revealed both substantial transformations and persistent congruities of imperial discourse from 1880-2017. The findings of this project demonstrate how hegemonic Euro-American geographic imaginations help construct tourism materials and influence tourist behaviour in Panama. In particular, themes of wilderness and nature, white supremacy, and America exceptionalism emerged from the analysis of tourism literature as the primary factors contributing to the conceptual and material organization of Panamanian space in travel literature. These themes are contextualized within broader discussions of empire studies and amenity migration literature.
“I’m still here”: an Ethnographic Exploration of Public Twitter Use among People Living with Advanced Cancer
Keywords: cancer
digital ethnography
liminality
palliative
social media
Twitter

Twitter is the most public of all social media platforms, and yet some users turn to this platform to share intimate details about their health. This ethnography explores public Twitter use among people living with advanced cancer with the aim of describing their Twitter activities and their perspectives on their use. Six latent themes were generated by analyzing 2,731 original tweets published by 8 authors and interview transcripts from 10 participants: 1) Constructing Identity Through Textual Selfie, 2) Resisting Social Death, 3) Accounting for Time, 4) Finding Freedom in Obscurity, 5) Creating a Living Legacy, and 6) Fighting for What’s Right. Through these themes, I argue that the technological affordances of Twitter can be used to counteract the inhibiting aspects of liminality. In using Twitter publicly, they declare ‘I’m still here’ to themselves, the people around them, and the world at large.
The Assessment of Hanging Behavior as a Measure of Mouse Welfare
Keywords: Animal Models of Pain
Hanging Behavior
Monitoring Animal Welfare
Pain

A decline in mice welfare can be indicative of underlying pathology. Often, these changes in mouse behaviors are difficult to detect before the pathology has significantly advanced. Our experiments have revealed that cage-lid hanging, a “luxury” behavior in mice, can serve as an indicator of welfare in different models of pain. The hanging behavior is identified as an event where a mouse climbs onto the metal lid of the laboratory cage, suspending itself off the cage floor. The goal of this project was to characterize and evaluate the hanging behavior of mice as a robust early indicator of a decline in physiological welfare. I observed that both acute and chronic pain models robustly reduced the frequency and duration of hanging behavior in mice. My results demonstrated that hanging behavior is a marker of mouse physiological and psychological welfare, that can be easily incorporated to facilitate the early detection of disease.
Real-World Multitasking Challenges in Younger Adults and Older Adults with and without Subjective Cognitive Decline
Keywords: Aging
Auditory processing
Dual-tasking
Postural control
Subjective cognitive decline

Age-related changes in postural control and/or cognition can be detrimental to multitasking performance. Previous studies investigating these effects have used paradigms not reflective of real-world challenges. Therefore, using a realistic multitasking paradigm in a virtual environment, this study examined age-related effects of performing a listening task while maintaining balance under varying levels of sensory/motor/cognitive challenge. Performance of individuals at potentially greater risk of cognitive decline (i.e., those with subjective cognitive decline (SCD)) was also evaluated. Results showed that older adults’ postural and listening performance was worse than younger adults, particularly under challenging conditions. Older adults with and without SCD exhibited comparable performance across conditions apart from the most challenging conditions, during which those with SCD demonstrated unexpectedly superior postural stability compared to those without. These findings demonstrate age-related decline in postural control and listening abilities, and suggest a prioritization of posture. Those with SCD did not demonstrate greater performance decrements.
Attention Deficit Hyperactivity Disorder Symptoms and Nonsuicidal Self-Injury among Clinically-Referred Children and Youth
Keywords: ADHD
Attention Deficit Hyperactivity Disorder
Child and Youth Mental Health Assessment
hyperactivity/impulsivity
inattention
Nonsuicidal Self-Injury

Nonsuicidal self-injury (NSSI; direct and deliberate damage of bodily tissue) is a widespread concern among clinically-referred youth. Individuals with Attention Deficit Hyperactivity Disorder (ADHD) may be at increased risk for NSSI engagement; however, ADHD consists of heterogeneous symptomatology, and there may be differential risk based on varying symptomatology. The current study investigated differential risk for NSSI engagement associated with selected hyperactive/impulsive symptoms and inattentive symptoms in a sample of 1006, 8-18-year-old children/youth from Ontario, Canada. The Children and Youth Mental Health Assessment (ChYMH) was used to collect all measures at intake into clinical care. Three binary logistic regression analyses were conducted to assess the predictive ability of selected hyperactivity/impulsivity symptoms, selected inattentive symptoms and a combination in predicting NSSI. Only the hyperactivity/impulsivity symptoms were significantly predictive of NSSI engagement over and above age, sex, anxiety symptoms and social disengagement. The results are discussed in the context of implications for prevention/intervention.
Transition to Adult Care for Youth with Severe Mental Illness: Does Continuity with Primary Care Matter?
Keywords: Adolescent
Adult Care
Mental Health
Primary Care
Transition
Young Adult

Objective: To analyze the association between primary care continuity and acute mental health care services following transition to adult care. Methods: Population-based retrospective cohort study using linked administrative health data of youth ages 12-17 with schizophrenia (SZ), eating disorders (ED), or mood and affective disorders (MAD) admitted between April 1, 2002 and April 1, 2010 in Ontario, Canada. Poisson regression models tested the association of primary care continuity and mental health outcomes after transition. Results: Among 3183 youth with severe mental illness, the majority (n=2,052, 64.5%) received continuous primary care during the transition period. Compared with continuous care, no primary care (n=190) during transition was associated with a 52% increased risk of a mental health admission following transition (aRR 1.52, 95% CI 1.12, 2.05). Conclusions: In the context of decreasing specialist mental health visits, ensuring adequate access to primary care during the transition period may improve outcomes in young adulthood.
A Longitudinal Spatiotemporal Analysis of Gait after Traumatic Brain Injury and an Assessment of Rhythmic Auditory Stimulation as a Gait Training Technique
Keywords: Gait
Longitudinal
Rhythmic Auditory Stimulation
Traumatic Brain Injury

Traumatic brain injury (TBI) can result in an array of motor and cognitive impairments. Walking difficulties are common following injury and can limit an individual’s ability to regain independence and achieve community integration. Rehabilitation is commonly used to treat gait-related issues and is in constant need of advancement and refinement. This thesis investigates: (1) the longitudinal change in spatiotemporal features of gait in the first year following TBI and the relationship between these changes and community integration, and (2) the feasibility of rhythmic auditory stimulation (RAS) as a gait training intervention to address chronic gait impairments of individuals living in the community with a TBI. Patterns of longitudinal spatiotemporal change are described and distinctions between severity groups are clarified. Next, the concurrent and predictive relationship between gait and community integration is elucidated. Lastly, the feasibility of RAS as a gait training technique in chronic TBI is further explored.
Microfluidics and Nanofluidics for Unconventional Resources in Micropores and Nanopores
Keywords: Microfluidics Nanofluidics

Unconventional resources play a crucial role in meeting the current global energy demand, however, production from these formations is challenging. The challenge mainly stems from either the extreme fluid properties (oil sands) or extreme rock properties (shale and tight sandstone). Primary production from unconventional reservoirs is very low which motivates testing and developing recovery strategies to improve the reservoir production. Micro/nanofluidic technologies have shown to be a promising tool to quantify the pore-scale recovery efficiency of different methods with a tight control over the operating conditions, i.e. pressure, temperature, and composition. In this work, we designed and developed two distinct micro/nanofluidic platforms to test some of the recovery methods for both bitumen and tight oil systems. This work highlights the unique potential of microfluidic and nanofluidic methods in resolving the pore-scale behavior of enhanced oil recovery processes under relevant reservoir conditions.
TRANEXAMIC ACID IN THE TREATMENT OF RESIDUAL CHRONIC SUBDURAL HEMATOMA: A SINGLE-CENTRE, OBSERVER-BLINDED, RANDOMIZED CONTROLLED TRIAL (TRACE)
Keywords: Chronic subdural hematoma
Randomized controlled trial
Tranexamic acid

Chronic subdural hematoma (CSDH) is a frequent consequence of head trauma, particularly in older individuals. Given the aging of populations globally, its incidence is projected to increase substantially. Hyperfibrinolysis may be central to CSDH enlargement by causing excessive clot degradation and liquefaction, impeding resorption. The only current standard treatment for CSDH is surgery, however, up to 31% of residual hematomas enlarge, requiring reoperation. Tranexamic acid (TXA), an antifibrinolytic medication that prevents excessively rapid clot breakdown, may help prevent CSDH enlargement, potentially eliminating the need for repeat surgery. To evaluate the feasibility of conducting a trial investigating TXA efficacy in residual CSDH, we conducted an observer-blinded, pilot randomized controlled trial (RCT). We showed this trial was feasible and safe, reporting only minor to moderate AEs, and an attrition rate of 4%. The results from this study will inform the conduct of a double-blinded RCT investigating TXA efficacy in post-operative CSDH management.