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History of Injury Enhances Sensory and Affective Responses to Subsequent Threatening Stimuli Through Increased Corticosterone in Male Mice
Get PDFPainful experiences are known to enhance memory formation, typically facilitating the consciousrecollection and avoidance of harmful stimuli. Emerging evidence also suggests that the consequences
of pain extend beyond cognition, affecting non-sensory biological processes. Despite this, little is
known about how transient pain experiences modulate sensory, affective, and hormonal responses to
subsequent threatening stimuli. In this series of experiments, I examined how a brief pain exposure
induced by paw injury using Freund’s Complete Adjuvant (CFA) influences responses to later painful
and non-painful threats. Male, but not female, mice with a prior paw injury showed heightened
sensory responses to subsequent pain at and beyond the site of the original injury. Follow-up
experiments indicated that CFA-primed males also exhibit amplified affective and sensory responses
to a non-painful threat (predator cue). This hypervigilance was mediated by TRPA1-dependent
regulation of the hormonal stress response. Additional experiments showed that the hormonal stress
response directly influences defensive behavior during predator threat by increasing freezing over
escape-driven strategies. Together, these findings suggest that stress sensitization may contribute
to hyperalgesic priming and modulate responses to cognitively driven threats, even in the absence
of direct somatosensory input.Ph.D
Designing For Less: Minimizing Embodied Emissions in Reinforced Concrete Residential Buildings
Get PDFThis thesis investigates key parameters to reduce the embodied emissions of reinforced concrete residential buildings, a crucial step to satisfy the urgent need to build more while emitting less, due to the climate and housing crises. The first study uses first-principles and structural modelling for 128 buildings, finding that while height has an impact on embodied emissions, slab thickness is nearly twice as influential. A 25 mm reduction in slab thickness offsets the emissions of 8 additional storeys. The second study uses nonlinear finite element analysis to investigate the minimum slab thickness under standard residential loading. The research finds that slabs could be designed at the minimum of 120 mm, showing a large opportunity to reduce emissions and material use with thinner slabs. The findings of this thesis highlight that the marginal increases in embodied GHG due to increased building height can be mitigated through careful design, facilitating more housing units with less resource use and embodied GHG.M.A.S
Highly Pathogenic Avian Influenza (HPAI H5N1, Clade 2.3.4.4b, genotype C2.1) in Commercial Ring-Necked Pheasants During the 2022 Outbreak in the United States
Get PDFHighly pathogenic avian influenza (HPAI) virus H5N1 clade 2.3.4.4b was introduced into North America in 2021. In 2022, clade 2.3.4.4b spilled into domestic poultry in the United States (U.S.), resulting in the largest HPAI outbreak in U.S. history. In December 2023, H5N1 2.3.4.4b was detected on an upland game bird farm in Pennsylvania. History, clinical signs, and gross lesions were suggestive of marble spleen disease. However, HPAI was identified by real-time reverse-transcriptase polymerase chain reaction; gene sequencing confirmed genotype C2.1 with phylodynamic analyses providing evidence of a wild bird introduction. Predictive mathematical modeling estimated the time of virus introduction onto the farm (15 days [95% C.I., 11 – 23] before the date of confirmed detection) being similar or longer than previously described for domestic poultry. Although bioexclusion measures were unable to prevent the initial exposure due to industry rearing practices, biocontainment procedures appeared to prevent spread. The lessons learned from this case may be important for other animal agriculture commodities, especially those species that are infrequently handled or observed and may have inaccurately calculated mortality levels. This well characterized outbreak and other experiences with natural infection should be taken as opportunities to better understand the field dynamics of this virus.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Risk Factors for Substance Use Disorder: An Integration of Delay Discounting and Emotional Regulation
Get PDFSubstance use disorders (SUDs) are highly prevalent and pose a major public health concern. Delay discounting, reflecting a preference for smaller immediate rewards over larger delayed ones, has been identified as a cognitive risk factor, with steeper discounting observed among individuals with SUDs and across increasing severity. However, limited research has investigated mechanisms underlying this relationship, and emotion regulation has been proposed as a potential mechanism. The present study examined how emotion regulation and delay discounting relate to SUD severity and frequency. Participants (N = 291) were recruited from the Cognitive Dysfunctions in Addictions Program, a longitudinal cohort study of adults seeking treatment for SUD, and completed a range of clinical and cognitive assessments. Greater SUD severity was associated with higher emotion dysregulation, but delay discounting was unrelated to SUD severity, frequency, or emotion regulation. Findings challenge the assumed centrality of delay discounting, suggesting limited theoretical and clinical relevance.M.A
Pathways for Decolonial FSL Literacies in Teacher Education
Get PDFThis research has been guided by an impetus for transformative educational change and a desire to broaden a vision for a renewed FSL (French as a Second Language) teacher education space. Within this broader context, I inquired about how French can be utilized as a decolonial language within French as a Second Language (FSL) teacher education, alongside the institutionalization of Indigenous Languages. Through the interplay of critical social justice education principles with educational praxis (Freire, 1972), Pathways for Decolonial FSL Literacies in Teacher Education (PaDFLiTE), a research-based pedagogical tool, was developed in response to two overarching imperatives: 1) to support transforming (educators’) self-awareness and praxis, and 2) to respond to the urgency to offer classroom implementation resources in support of decolonization. I have engaged with the concept of ethical spaces of engagement (Cree scholar Ermine, 2007) in support of UNlearning and RElearning, which are necessary for the emergence of new encounters between Indigenous and Euro-Western worldviews and pedagogies within the FSL teacher education space in B.C., extending to minority francophone settings, and beyond. This work supports the ongoing, multilayered process required in the current need to decolonize educational settings in Canada and beyond. This stance is reflected in its core social justice principle, which seeks justice and equity from a place of marginalization and systemic oppression, where Indigenous knowledges and ways of learning and being have been erased from the educational space. The eight modules also center on Indigenous authors’ work and scholarship. As a resource to propel future French settler teachers toward meaningful action, this research has demonstrated the pressing need to better equip future French teachers. It highlights the transformative power of teacher education. By empowering future French settler educators as agents of social change, this research contributes to an urgent call for an Indigenous-settler relational renewal (Donald, 2022) within the French educational space.
As a minoritized and often marginalized language in Anglo-dominant contexts, I have proposed that a thoughtful engagement with PaDFLiTE can offer initial steps towards redefining the French language and teaching space as a more inclusive, diverse, and critically settler-aware language education space in an era of reconciliation.
Globalement, cette recherche vise à explorercomment soutenir les enseignant.e.s. de français
(FSL) actuels et futurs, à tailler un espace pour les
perspectives et les pédagogies autochtones, là où
dominent traditionnellement les théories, les textes
et les approches plus euro-centrées et
traditionnelles. Nous explorerons le contexte
multilingue et multiculturel changeant, au niveau
régional, provincial et national ainsi que des impacts
sur l’enseignement et l’apprentissage du français en
milieu M-12. Dans une perspective qui puisse
reconnaitre et prendre en compte des complexités
liées à l’enseignement du français, à la fois langue
minorisée en milieu minoritaire, nous explorerons
des implications pratiques potentielles dans un
cadre qui soutient un engagement à la diversité, à
l’inclusion et à la décolonisation. La relation entre
les récits autochtones, les récits alternatifs et les
approches ancrées dans l’enseignement
du plurilinguisme et des multimodalités seront aussi
explorées.Ed.D
Plant Polysaccharide Amination via Two-step One-pot Biocatalytic Cascades
No full textAminated polysaccharides are biocompatible, polycationic, and antimicrobial biopolymers used extensively infood, agricultural, pharmaceutical, and environmental applications. Chitin and chitosan, major forms of aminated
polysaccharides in nature, are sourced mainly from seafood residuals and have limited diversity in structure and
properties. In contrast, plant polysaccharides are structurally versatile and have well-established procedures for
harvesting; their aminations to generate chitosan analogs can take advantage of existing processes and introduce
non-native properties suitable for a broader range of applications. In this study, a two-step enzymatic oxidation-transamination cascade employing galactose oxidases (GalOxs) and amine transaminases (ATAs) was designed to
aminate plant polysaccharides in a one-pot process. Initial activity screening via the acetophenone assay identified
ATAs from Chromobacterium violaceum (CvATA) and Silicibacter pomeroyi (SpATA) as promising candidates. A
quantitative colorimetric assay was developed to enable accurate measurement of aminated product yield, and
the two ATAs were thereby compared. Despite the higher initial rates of CvATA, SpATA generated higher aminated
product yields on oxidized carbohydrates thanks to its higher operational stability. Experiments under various
operating conditions showed that side reactions, such as hydrogel formation, can be suppressed by balancing
enzyme activities; however, the low operational stability, resulting from the low cofactor affinity of ATA, remains
a major factor limiting the cascade yield. Via a modified acetophenone assay with high cofactor concentrations,
rates of aminated product formation and cofactor amination by candidate ATAs were simultaneously measured,
and a kinetic model based on the ATA transamination and deactivation mechanisms was established. Based on
the results of molecular dynamics simulation, a cofactor dissociation pathway initiated by solvent attack was
proposed for fold type I ATAs, and an amino donor inhibition-induced deactivation mechanism was hypothesized, considering the multimeric nature of active ATAs. Sequence analysis of fold type I ATAs revealed a conserved set
of amino acids near the cofactor binding site, which possibly affects the cofactor affinity. Although CvATA mutants
containing identified amino acids could not be solubly expressed, bioinformatic-based approaches should be
explored further to identify sequence and structural features responsible for high cofactor affinity and thus high
operational stability of fold type I ATAs.Ph.D
Broadband Analog Time-Interleaving for 200+ GBaud Fibreoptic Systems
Get PDFAs fibre-optic communication systems scale beyond one terabit per second, conventional CMOS-based digital-to-analog and analog-to-digital converters increasingly struggle to meet the required bandwidth and power efficiency. Analog time-interleaving has emerged as a viable solution for extending symbol rates without the complexity and power overhead of digital processing at ultra-high speeds.
This thesis investigates broadband analog time-interleaving as a technique for extending effective sampling rates while maintaining energy-efficient operation. A novel analog multiplexer architecture is designed and implemented in a 22 nm FDSOI CMOS process, leveraging the technology’s back-gate biasing capability to enhance performance and allow for a built-in equalizer. The circuit achieves operation up to 192 GBaud using PAM-4 modulation, the highest symbol rate reported for an AMUX in any technology to date. It exhibits a spurious-free dynamic range of 32 dB for a 1 GHz sinusoidal input and consumes a total of 185 mW, with only 64 mW attributed to the novel merged AMUX-equalizer stage.
The design is validated through schematic simulations, full layout implementation, post-layout verification, and experimental measurements. The results demonstrate the feasibility of using advanced CMOS nodes for broadband time-interleaving, offering a compelling alternative to traditional high-speed technologies such as SiGe BiCMOS and InP HBT. This work contributes a scalable and energy-efficient solution for future high-speed optical transceivers.M.A.S
Neuroanatomical Changes Accompanying Surgical Response in Trigeminal Neuralgia
Get PDFTrigeminal neuralgia (TN) is a severe, chronic neuropathic facial pain condition. Although TN can be highly amenable to surgical treatment, ~25% of patients remain in pain. Thirteen cortical regional predictors of surgical response were previously identified using pre-surgical cortical thickness in TN. In this thesis, I examined how these response predictors changed following surgical treatment. Retrospective imaging data was acquired from surgically naïve TN patients before and 6-12 months after undergoing Gamma Knife Radiosurgery (GKRS). 116 patients (73F:43M) were categorized as surgical responders (≥ 75% pain relief), partial responders (50-74% pain relief), or non-responders (<50% pain relief). Eight regions within default mode, visual, limbic, and dorsal attention networks had significant (p < 0.05) changes in cortical thickness, with responders having the most widespread and significant change. Thickening of the fusiform gyrus was significantly correlated with the degree of pain reduction, highlighting this region in the process of post-surgical pain relief.M.Sc
Radical Transformation of Nursing Education in Ontario: Multiple Case Study of Four Ontario Colleges
Get PDFIn this study I sought to explore the forces that led to Ontario’s Ministry of Colleges and Universities (MCU) policy reform of 2020 which permits colleges and universities to offer standalone nursing degree programs. While the policy impacts both colleges and universities, this study focused on the forces of change specifically for the Ontario Colleges of Applied Arts & Technology (CAATs). Using a multiple case study research design, I explored the factors that led each of the four participating case study Ontario CAATs to move forward in implementing a standalone baccalaureate nursing degree program at their institution. I examined their experiences and the processes undertaken in the development and implementation of these programs. Study findings were generated from document analysis, semi-structured interviews with ten participants responsible for the program conceptualization, development and implementations and from cross case study analysis. To understand the political nature of state authority, the role of market demands, and the broader impact on nursing education policy, Burton Clark’s (1983) "triangle of coordination" was applied as a theoretical framework. This framework facilitated the analysis of how state, market, and academic oligarchy intersected in shaping the policy and its outcomes. Key findings revealed that political advocacy led by the CAATs and Colleges Ontario, combined with key stakeholder support from policy actors exerting high influence on government. Furthermore, intermediary bodies, specifically the College of Nurses of Ontario and the Post Secondary Quality Assurance Board (PEQAB) played a key role in facilitating this policy change. Moreover, the findings illustrate that political will fostered by a critical nursing shortage and compounded by the COVID-19 pandemic were critical enablers. This study highlights the intersecting and dynamic roles of government, market and academic oligarchy in transforming the nursing education landscape in Ontario. Implications of these findings consider the policy and practice consequences and contributions to this higher education policy reform, particular as the complexity of healthcare increases, the demand for a greater skilled nursing workforce continues and access to higher education remain paramount for entry to practice in nursing.Ph.D
Dissection of the Light-Modulated Changes in Social Behaviour and Underlying Cerebellar Dynamics in Zebrafish
Get PDFSocial behaviour is crucial for the survival and reproduction of many species. Recent studies show that both cerebellar dysfunction and light cycle modulation can impair social behaviour, resulting in similar deficits, such as decreased interactions with conspecifics. However, it remains unclear if light-cycle-induced changes in social behaviour are mediated by cerebellar mechanisms. To study this question, this project uses zebrafish (Danio rerio) to examine shoaling differences after light cycle modulation and to identify a social stimulus to dissect the involved cerebellar circuitry. I found that altered light cycles reduce social attraction and change orienting angles in zebrafish, with an inverted light cycle affecting most behavioural parameters. These results identified the inverted light cycle as a useful experimental condition to probe neural activity and investigate whether light-modulated changes in social behaviour are regulated by the cerebellum.M.Sc