Digital Commons Network^™

Vascular Tree Structure: Fast Curvature Regularization And Validation, Egor Chesakov

Electronic Thesis and Dissertation Repository

This work addresses the challenging problem of accurate vessel structure analysis in high resolution 3D biomedical images. Typical segmentation methods fail on recent micro-CT data sets resolving near-capillary vessels due to limitations of standard first-order regularization models. While regularization is needed to address noise and partial volume issues in the data, we argue that extraction of thin tubular structures requires higher-order curvature-based regularization. There are no standard segmentation methods regularizing surface curvature in 3D that could be applied to large 3D volumes. However, we observe that standard measures for vessels structure are more concerned with topology, bifurcation angles, and other …

The Effects Of Warming Temperatures, Fire, And Landscape Change On Lake Production In Mountain Lakes, Alberta, Canada, Amber Elizabeth Gall

Electronic Thesis and Dissertation Repository

Many factors could be causing the widespread eutrophication being observed globally, including natural and human factors. In the mountainous regions of Alberta, Canada, warming temperatures, increased fire occurrence, and greater landscape disturbance could increase lake production. To determine the effects of these factors, proxies of lake production preserved in lake sediment records that span the last 1000 years were measured. These records are from two lakes that have not been affected by direct nutrient inputs from human activities; one in Jasper National Park and one from the Hinton area (Alberta). The results highlight that there is little effect of fire …

A Sociomaterial Analysis Of Team-Based Care For Patients With Advanced Heart Failure, Allan Glen Mcdougall

Electronic Thesis and Dissertation Repository

This dissertation explores team-based care for patients with advanced heart failure (HF), especially care practices associated with integrating palliative care. Its three integrated articles explore advanced HF care as a team-based health care phenomena, focusing on both objects and people as integral for team activity. The dissertation utilizes the theoretical framework of sociomaterialism to explore the overarching research question: how do materials mediate and influence the integration of palliative and cardiac care for patients with HF? Study data take the form of 15 team sampling units (TSU), each of which consists of a patient interview and an interview with at …

The Rho Gtpases Rac1, Cdc42, And Rhoa Regulate App Transport To Lysosomes And Aβ Production, Justin K. Chiu .

Electronic Thesis and Dissertation Repository

Alzheimer’s Disease (AD) is characterized by Beta-Amyloid (Aβ) plaques within the brain. Aβ peptides are produced by the cleavage of Amyloid Precursor Protein (APP). Our lab has previously discovered a novel pathway for APP internalization mediated by ADP-ribosylation factor 6 (Arf6). This pathway resembles macropinocytosis, transporting cell surface APP directly to lysosomes, a possible site for Aβ production. We set out to characterize the effectors downstream of Arf6. In SN56 and N2A cells we co-transfected HA-tagged APP (to label cell-surface APP) with compartment markers, to visualize APP trafficking. We used dominant negative and constitutively active mutants, pharmacological inhibitors, and siRNA …

Phase Ii Clinical Trial Of Concurrent Neoadjuvant Chemotherapy With Radiotherapy In Locally Advanced Breast Cancer, Muriel Brackstone

Electronic Thesis and Dissertation Repository

Locally advanced breast cancer (LABC) represents 15% of all non-metastatic breast cancers, with an overall poor prognosis, despite current guidelines that recommend neoadjuvant chemotherapy followed by surgery and adjuvant radiation. Therefore, a novel treatment paradigm using concurrent neoadjuvant chemoradiotherapy was proposed. A clinical trial was designed, where 32 LABC patients were treated with q3 weekly 5-fluorouracil, epirubicin and cyclophosphamide for three cycles, followed by weekly docetaxel for 9 weeks with concurrent regional radiation (45+5.4Gy) for the first 6 weeks. Patients subsequently underwent modified radical mastectomies. Pathological complete responses (pCR) and 3 year overall survival rates were compared to a matched …

Recent Discoveries In The Ni-Cu-Pge Bearing Trill And Parkin Offset Dykes, Sudbury Impact Structure, Canada, Adam B. Coulter

Electronic Thesis and Dissertation Repository

The Sudbury structure hosts world class Ni-Cu-PGE deposits that have been mined, explored and studied for over 130 years. The structure is widely recognized as the erosional remnant of a 1.85 Ga 200- to 250-km tectonically altered multi-ring impact basin located in central Ontario, Canada. The focus of this investigation is on the Trill and Parkin Offset dykes. This study provides updated regional scale geologic maps, detailed geologic maps of newly exposed sections, geochemistry, sulphide analysis and an analysis of the inclusion population and orientation within the dykes. We conclude, the dyke phases display remarkable geochemical homogeneity, the Ni-Cu-PGE mineralization …

Polyhydroxybutyrate Production In A Photobioreactor Using Spirulina Platensis, Adrianna Mika

Electronic Thesis and Dissertation Repository

Biopolymers and other naturally derived chemicals continue to gain attention over petrochemical based products due to the price volatility of crude oil, increasing need to reduce greenhouse gas emissions and public awareness of environmental issues. Cyanobacterium Spirulina (Arthrospira) platensis, a commercially feasible blue-green alga, is able to synthesize poly(3-hydroxybutyrate) (PHB), a biodegradable and biocompatible polymer, as an energy storage product of photosynthesis directly from CO₂. A flat plate photobioreactor (PBR) with LED illumination was designed for the cultivation of S. platensis. Computational fluid dynamics (CFD) software was used to improve airflow uniformity and mixing in the …

Evidence Reversal: When New Evidence Contradicts Established Practices, Desiree S. Sutton

Electronic Thesis and Dissertation Repository

Evidence reversal occurs when new evidence contradicts established practices. The first component of this thesis is an umbrella overview of investigations – reviews and collections of studies – into evidence reversal to gather concepts and methods that we identified as useful to lay a foundation for a standardized ‘theory of reversal.’ The foundation of this review enables the construction of a framework that will provide structure to this field, as no formal organization currently exists. The next component builds upon this foundation and proposes a framework for evidence reversal and its related concepts. The second review takes this framework …

An Ethnographic Study Examining Nurse-Client Relationships In A Jordanian Mental Health Care Setting, Wafa'a Falah Ta'an

Electronic Thesis and Dissertation Repository

An Ethnographic Study Examining Nurse-Client Relationships in a Jordanian Mental Health Care Setting

The nurse-client relationship is viewed as the primary human contact that is crucial to providing nursing care. Interaction processes need to be investigated within their cultural context in order for the nurses to establish a therapeutic nurse-client communication that is congruent with the culture in which it takes place.

The purpose of this study was to explore and describe the Jordanian mental health care system, and investigate how the cultural values and beliefs of Jordanians shape nurse-client relationships. The study utilized an ethnonursing approach. Data were collected …

Serotonergic System And Gait: Dorsal Raphe Nucleus As A Control System For Gait, Nahal Farhani

Electronic Thesis and Dissertation Repository

In advanced stages of Parkinson Disease (PD), gait and postural abnormalities emerge. These symptoms are not prominent at early stages of PD despite significant dopaminergic neuronal loss. Gait abnormalities are largely not responsive to levodopa. Therefore, other types of neurons might be responsible for gait abnormalities of the PD.

Since the reticulospinal tract (RET) is mainly implicated in the control of axial muscles, the degeneration of this pathway or populations of neurons controlling this pathway might be responsible for axial symptoms. However, there is limited data about the neurons controlling the RET. Our aim in this study is to delineate …

Sexual-Economic Entanglement: A Feminist Ethnography Of Migrant Sex Work Spaces In Kenya, Megan Lowthers

Electronic Thesis and Dissertation Repository

The recent anti-trafficking fervour as well as the moral panic surrounding prostitution has given rise to large gaps within migrant sex work research, especially in Africa. Despite this, sexual commerce remains a viable economic activity for many women in East Africa, a region where variable migration patterns are central to everyday social, cultural, and economic life. Framed by anthropology, feminist geography, and postcolonial theory, this research examines migrant female sex workers’ everyday experiences across time, space, place, and scale from one ethnographic location in Naivasha, Kenya. In order to explore how different migration patterns and types of sexual-economic exchange are …

Females In Control: Female Sensitivity To Predation Risk Affects Courtship And Reproductive Behaviours, Tin Nok Natalie Cheng

Electronic Thesis and Dissertation Repository

Even in the absence of direct killing, predators have a pervasive effect on prey populations through costly anti-predator behavioural responses. In high risk environments, animals can reduce conspicuous behaviours such as courtship displays decreasing exposure at the cost of reproduction. Previous studies typically looked at male behaviour immediately following a predator cue, thus, not considering temporal variations in risk or the impact of female receptivity on male courtship. I placed male and female brown-headed cowbirds under chronically elevated predation risk with periods of high and low risk. Under high predation risk, females performed fewer chatter calls and were more likely …

The Role Of Thymine Dna Glycosylase (Tdg) And Dna Demethylation In Tgf Beta Signaling, Matthew E.R. Maitland

Electronic Thesis and Dissertation Repository

Prompted by findings that TGFβ stimulates thymine DNA glycosylase (TDG) dependent rapid DNA demethylation and activation of the CDKN2B gene, I investigated the global role of TDG and DNA demethylation in TGFβ signaling in HaCaT cells. Using dot blot analysis, I show that TGFβ treatment increases the global levels of 5-formylcytosine, an intermediate metabolite of active DNA demethylation. Characterization of genomic regions that undergo DNA demethylation and recruitment of TDG indicate that they are both frequent events, but only overlap at 11 genomic locations. I identified 440 TGFβ upregulated genes, 40 of which were bound by TDG and 169 that …

Grasping For The Ends Of The Earth: Framing And Contesting Polar Sovereignty, 1900-1955, Peter Kikkert

Electronic Thesis and Dissertation Repository

During the first half of the twentieth century, state officials, international lawyers and polar experts struggled to apply an underdeveloped and unclear international legal discourse on territorial acquisition and the establishment of state sovereignty to the harsh environment and unique conditions of the Arctic and Antarctic. Drawing upon fresh archival research undertaken in several countries, as well as a thorough interrogation and synthesis of existing historical and legal scholarship, this dissertation explores the knowledge production that occurred on terrestrial polar claims, thus reconstructing the transnational web of ideas, adaptations, strategies and best practices developed to address the confusion and uncertainty …

Semantic Integration In Adults With Nonverbal Learning Disabilities And Autism Spectrum Disorder: Influence Of Word Knowledge And Gestalt Perception, Margot E. Stothers

Electronic Thesis and Dissertation Repository

Language in individuals with nonverbal learning disabilities (NLD) and autism spectrum disorder (ASD) has been described as semantically empty and impoverished, despite apparently average word knowledge. Here, inter-related studies explored semantic representations in adults with these disorders of social perception. Studies highlighted semantic integration, a form of gestalt perception in which new concepts are developed by connecting familiar terms in novel ways. Semantic integration was compared to vocabulary breadth, and to nonverbal gestalt perception, comparing clinical groups to each other and to adults without a diagnosis. Because weaknesses in gestalt perception have been seen in NLD and ASD, it was …

The Rational Design And Evaluation Of Ck2alpha Mutants Bearing Inhibitor-Refractory Amino Acid Substitutions, Sam Reid Fess

Electronic Thesis and Dissertation Repository

CK2 is a ubiquitously expressed and constitutively active serine/threonine protein kinase that is implicated in many cellular functions. Previous studies have indicated that the generation of mutants that are less sensitive to inhibition can be advantageous when studying protein kinases. Importantly, studies have demonstrated that mutants of CK2 rendered less sensitive to inhibition are attainable. To extend these observations, mutants of CK2α were designed and evaluated to test their effect on the inhibition of CK2 by CX-4945 using in vitro enzymatic assays followed by the development of inducible cell lines. CX-4945 is a CK2 inhibitor that has demonstrated anti-tumor activity …

Exercise Identity: Origins, Applications, And Future Utility, Vincent L. Liardi

Electronic Thesis and Dissertation Repository

It has been determined that exercise identity (EI) is a key component of the self-concept and is a strong determinant of exercise behaviours. The primary purpose of study 1 was to examine EI’s relationship with three key self-presentational variables: self-presentational efficacy (SPE), social physique anxiety (SPA), and impression motivation (IM). Specifically, we looked at how EI contributed uniquely to predicting exercise behaviour over and above these self-presentational concerns. The analyses demonstrated that EI is positively correlated with SPE and unrelated to SPA in both genders. Further analyses revealed that EI contributes a significant amount of variance towards exercise behaviour over …

Quality Of Life And Subjective Outcomes Following Maxillomandibular Advancement Surgery For The Treatment Of Obstructive Sleep Apnea, Andrew D. Emanuele

Electronic Thesis and Dissertation Repository

Objective: The aim of this study was to assess outcomes related to general quality of life, daytime sleepiness and functional sleep outcomes, functional outcomes of orthognathic surgery, and facial aesthetics in patients undergoing maxillomandibular advancement (MMA) surgery for the treatment of obstructive sleep apnea (OSA).

Materials and Methods: This was a cross-sectional self-report study. A questionnaire was constructed using questions drawn from previously validated questionnaires. The survey was distributed to 25 patients who underwent MMA surgery for the treatment of OSA at LHSC in London, Ontario by a single surgeon between 2002 and 2013.

Results: The survey results showed that …

The Role Of Bone Sialoprotein In Periodontal Tissue Development And Bone Repair, Yohannes Soenjaya

Electronic Thesis and Dissertation Repository

Bone development and repair involve complex processes that include interaction between cells and their surrounding matrix. In the body, bone sialoprotein (BSP) expression is up-regulated at the onset of mineralization. BSP is a multifunctional acidic phosphoprotein with collagen-binding, hydroxyapatite nucleating, and integrin recognition (RGD sequence, which is important for cell-attachment and signaling) regions. Mice lacking BSP expression (Bsp^-/-), exhibit a bone phenotype with reductions in bone mineral density, bone length, osteoclast activation, and impaired bone healing. This thesis examined the role of BSP in tooth development and also its potential use as a therapeutic reagent for bone …

Moral Sense Theory And The Development Of Kant's Ethics, Michael H. Walschots

Electronic Thesis and Dissertation Repository

This dissertation investigates a number of ways in which an eighteenth century British philosophical movement known as “moral sense theory” influenced the development of German philosopher Immanuel Kant’s (1724-1804) moral theory. I illustrate that Kant found both moral sense theory’s conception of moral judgement and its conception of moral motivation appealing during the earliest stage of his philosophical development, but eventually came to reject its conception of moral judgement, though even in his early writings Kant preserves certain features of its conception of moral motivation. In the mature presentation of his moral philosophy Kant offers detailed objections to moral sense …

Limitation To Innovation In The North American Console Video Game Industry 2001-2013: A Critical Analysis, Michael Schmalz

Electronic Thesis and Dissertation Repository

In today's marketplace the ability to innovate is considered a key driver of success and economic prosperity (Florida, 2002; Howkins, 2001). From an innovation perspective, video game development has often been viewed as an exemplary case of a creative digital industry whose products and services are quickly consumed and hence require a constant flow of new content. This dissertation reviews innovation in the video game industry more critically. After examining the main lines of contemporary innovation theory, it proposes a model of the innovation process in the development cycle of console video games, evaluating the roles of three principle actors: …

Intracellular Acidification In Brain Tumors Induced By Topiramate : In-Vivo Detection Using Chemical Exchange Saturation Transfer Magnetic Resonance Imaging, Kamini Y. Marathe

Electronic Thesis and Dissertation Repository

Glioblastoma Multiforme (GBM) is the most aggressive and malignant form of primary brain tumor. In many tumors, increased intracellular pH (pH_i) is a hallmark of aggressiveness. This increased pH_i has been shown to be related to cell proliferation and evasion of apoptosis as well as resistance to chemotherapy. As such, monitoring pH_i and the tumor pH_i response to pharmacologic challenge, may aid in treatment planning and patient management for this deadly cancer. A magnetic resonance imaging (MRI) method called Chemical Exchange Saturation Transfer (CEST) has been used to detect changes in pH_i. Our group …

Investigation Of Cell-Penetrating Peptide Transformation In Two Regenerable Tissue Culture Systems, Atiyyah S. Ferouz

Electronic Thesis and Dissertation Repository

The genetic engineering of plants allows for the modification of plant genomes, subsequently improving plant traits. There are, however, plants recalcitrant to established transformation methods, requiring the implementation of novel techniques. This study investigates the viability of cell-penetrating peptide (CPP) transformation using Tat₂, a CPP with demonstrated transformation efficiency in plant and animal systems, in two regenerable tissue culture systems, soybean somatic embryos and Arabidopsis protoplasts. Assessments of complex formation, Tat₂ cellular translocation, complex uptake, and CPP-mediated transformation were carried out. The results show the formation of a Tat₂-plasmid complex and the uptake of Tat …

Smoking And Exercise: Mechanisms And Effects During Simulated And Genuine Quit Attempts, Stefanie De Jesus

Electronic Thesis and Dissertation Repository

Cigarette smoking is a leading agent for premature morbidity and mortality among the global community. Most individuals surrender to tobacco use disorder due to the inability to cope with cravings and withdrawal symptoms. Exercise appears to provide acute relief. Currently, it is unclear how exercise attenuates these reductions. Furthermore, the available evidence has focused on acute outcomes besides smoking behaviour and is limited to simulated quit attempts. Three experimental studies were designed to address these outstanding issues. Not surprisingly, a bout of moderate intensity exercise was found in study 1 (chapter 2) to reduce cravings associated with a temporary period …

Security Protocol Suite For Preventing Cloud-Based Denial-Of-Service Attacks, Marwan M. Darwish

Electronic Thesis and Dissertation Repository

Cloud systems, also known as cloud services, are among the primary solutions of the information technology domain. Cloud services are accessed through an identity authentication process. These authentication processes have become increasingly vulnerable to adversaries who may perform denial-of-service (DoS) attacks to make cloud services inaccessible. Several strong authentication protocols have been employed to protect conventional network systems. Nevertheless, they can cause a DoS threat when implemented in the cloud-computing system. This is because the comprehensive verification process may exhaust the cloud resources and shut down cloud’s services. This thesis proposes a novel cloud-based secure authentication (CSA) protocol suite that …

Should Voters Decide? Exploring Successes, Failures And Effects Of Electoral Reform, Nicholas J. Caruana

Electronic Thesis and Dissertation Repository

Are Citizens’ Assemblies useful tools for reforming democratic institutions and addressing the democratic deficit? Evaluating the utility of using mini-publics to deliberate issues like electoral reform based only on their record of success does not recommend this approach. But this sort of assessment is weakened by a lacuna in the study of Citizens’ Assemblies: we do not know whether such deliberative bodies, thanks to their inherent high levels of democratic participation, might have added democracy-enhancing value over and above traditional elite-centric reforms. This dissertation establishes a theoretical model for evaluating whether a particular path to electoral reform has independent effects …

Mathematical Modeling Of Stress Management Via Decisional Control, Matthew J. Shanahan

Electronic Thesis and Dissertation Repository

Engaging the environment through reason, humankind evaluates information, compares it to a standard of desirability, and selects the best option available. Stress is theorized to arise from the perception of survival-related demands on an organism. Cognitive efforts are no mere intellectual exercise when ontologically backed by survival-relevant reward or punishment. This dissertation examines the stressful impact, and countervailing peaceful impact, of environmental demands on cognitive efforts and of successful cognitive efforts on a person’s day-to-day environment, through mathematical modeling of ‘decisional control’. A modeling approach to clinical considerations is introduced in the first paper, “Clinical Mathematical Psychology”. A general exposition …

Mothers Experiencing Homelessness: Social Exclusion, Resistance, And Health, Sarah Benbow

Electronic Thesis and Dissertation Repository

Background and Purpose: Mothers experiencing homelessness in Canada are faced with unique challenges in achieving health. The purpose of this two-phase study was to critically examine the socio-political context, health needs, exclusionary and inclusionary forces, and strategies of resistance demonstrated by mothers experiencing homelessness.

Methodology: This study falls under the critical paradigm informed by the theoretical perspective of intersectionality. Methodologies employed included critical narrative and critical discourse analysis. Data were collected at various homeless shelters and programs that provide services for women and mothers who are homeless in Southern Ontario. A purposive sample of women experiencing homelessness, and service …

Fear Of Predators Compromises Parental Care And Juvenile Survival In A Songbird, Philip Blair Dudeck

Electronic Thesis and Dissertation Repository

Predators kill, but the risk of being killed is also a powerful force affecting survival because scared prey eat less, thereby increasing the likelihood of starvation. Young of most animals are extremely vulnerable to predators and may alter their behaviour to limit detection. I investigated the previously unexplored effects that predation risk has on the behaviour of newly fledged offspring and their parents, and the impact this has on offspring survival. I manipulated predation risk using sound and found that parent song sparrows reduced their feedings, providing 60% less food overall. Critically, not only did this parental response estimate survival …

Towards The Development Of A Wearable Tremor Suppression Glove, Yue Zhou

Electronic Thesis and Dissertation Repository

Patients diagnosed with Parkinson’s disease (PD) often associate with tremor. Among other symptoms of PD, tremor is the most aggressive symptom and it is difficult to control with traditional treatments. This thesis presents the assessment of Parkinsonian hand tremor in both the time domain and the frequency domain, the performance of a tremor estimator using different tremor models, and the development of a novel mechatronic transmission system for a wearable tremor suppression device. This transmission system functions as a mechatronic splitter that allows a single power source to support multiple independent applications. Unique features of this transmission system include low …