Theses, Dissertations, and other Required Graduate Degree Essays

This thesis highlights justice in the words of Indigenous Elders living on Unceded Coast Salish Territory. Multiple interviews were held with four Indigenous Elders from four different nations to obtain their perspective on current justice issues affecting today’s Aboriginal people/s within the Canadian urban context of Vancouver, British Columbia. Although the core data for this thesis involved extensive interviewing of each Elder, the methodology also sought to understand "justice" through a two-eyed seeing lens that embraced both Indigenous and western approaches to knowledge. Interviews gave Elders an opportunity to share the work each has done to find justice in their personal and professional lives. These were supplemented by participating in culturally-driven justice sites as guided by one Elder-Mentor who sought to demonstrate justice experientially. This Elder’s journey to embody justice through traditional values, ceremony, and advocacy work serves as one of the central voices in this exploration of justice.

This thesis describes a novel microfabrication process to produce thick-film copper microstructures that are embedded in polydimethylsiloxane (PDMS). This process has reduced fabrication complexity and cost compared to existing techniques, and enables rapid prototyping of designs using minimal microfabrication equipment. This technology differs from others in its use of a conductive copper paint seed layer and a unique infrared-assisted transfer process. The resulting microstructures are embedded flush with the PDMS surface, rather than on top, and adhere to PDMS without the need of surface modifications. The 70-micrometers-thick copper layer has a surface roughness of approximately 5 micrometers, a low film resistivity of 2.5-3 micro-Ohm-cm, and can be patterned with feature sizes of 100 micrometers. The low-cost, thick metal films demonstrate a comparative advantage in high-current, low-power applications, with feature sizes and metal layer properties that are otherwise comparable to similar processes. Several applications are fabricated, including stretchable interconnects integrated with fabrics for wearable devices and a multi-layer electromagnetic microactuator with a soft magnetic nanocomposite polymer core for large magnetic field generation. The interconnects can accommodate strains of 57 percent before conductive failure, which is similar to existing technology, and demonstrate a significantly lower resistance of less than 0.5 Ohm per device. The actuator produces an average magnetic field of 2.5 milli-Tesla per volt applied within a cylindrical volume of 34 cubic millimeters. Simulations indicate that fields of up to 1 Tesla are possible for 200 micro-second input pulses, and that significantly larger fields are achievable through simple design modifications. These results are comparable to existing devices, while our device has the advantage of being fully flexible, low-cost, and is easily integrated with various substrates and polymer microfabrication processes.

Fitting broadly under the category of target-oriented synthesis of complex organic molecules, the work described in this document pertains primarily to exploiting the facile organocatalytic synthesis of enantiomerically enriched α-chloroaldehydes, drawing out their potential through conversion into 1,2-chlorohydrins, and exploring the means by which these substances may be coerced to undergo intramolecular cyclization involving a nitrogen nucleophile. Specific targets and methodology include a successfully completed synthesis of the natural product (+)-preussin and similarly substituted pyrrolidines through the reductive annulation of β-iminochlorohydrins, a formal synthesis of (-)-swainsonine and related alkaloids through a related intramolecular cyclization strategy, and the synthesis and structural analysis of a carbocyclic mechanism-based inactivator of a glycoside hydrolase. As a secondary focus, this thesis also describes the isolation, structural elucidation, and testing of the long-range sex pheromone of the strepsipteran Xenos peckii, which was ultimately determined to be (7E,11E)-3,5,9,11-tetramethyltridecadienal, and of the chemical constituents of the bed bug (Cimex lectularius) aggregation pheromone, which were ultimately determined to be dimethyl disulfide, dimethyl trisulfide, (E)-2-hexenal, (E)-2-octenal, 2-hexanone, and histamine.

This research is concerned with wayfinding, one of the most basic interactions of 3D action-adventure games. Even though players are required to move from point A to point B to progress in games, there is little research on the difficulties, needs, and preferences of players regarding wayfinding in 3D game worlds. It is well known that to alleviate wayfinding issues, designers add wayfinding cues to the game world. However, little is known about how those cues affect players’ in-game behavior and, more importantly, the player experience. This research addresses those issues by investigating players’ responses to a variety of wayfinding cues. To this end, I developed two research tools resembling commercial 3D action-adventure games. Both games (i.e., The Lost Island and A Warrior’s Story) presented several wayfinding cues and tasks, purposefully designed to make players move from one space to the next. I investigate the player experience through mixed method and user-centered approaches, collecting and analysing quantitative and qualitative data. In the first study, all participants played the same version of The Lost Island, and I emphasized the differences between the experiences of more and less skilled players. For the second study, I categorized wayfinding cues into three groups that worked as my independent variables. Participants played one of the three versions of the game (i.e., experimental conditions) and reported on their experiences. Through concrete examples, this work demonstrated how wayfinding cues had an impact on players’ wayfinding behavior and attitude towards the games. Design implications are also discussed. I hope this work will assist wayfinding researchers in their future investigations, and assist wayfinding system designers in creating and ameliorating their systems for a more profound user experience.

The basic Helix-Loop-Helix/PER-ARNT-SIM (bHLH-PAS) domain family of proteins mediates cellular responses to a variety of stimuli. The bHLH-PAS proteins are heterodimeric transcription factors that are further sub-classified into sensory and aryl hydrocarbon receptor nuclear translocator (ARNT) proteins. The ARNT protein is constitutively expressed and heterodimerizes with hypoxia-inducible factors (HIFs) to mediate oxygen-sensing mechanisms and heterodimerizes with the aryl hydrocarbon receptor (AHR) to combat environmental contaminant exposure. Firstly, a reciprocal disruption relationship exists between AHR ligands, like 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and estrogen receptor (ER) ligands, like 17β-estradiol (E2). Ligand-bound ER tethers to the AHR/ARNT transcription factor complex and represses TCDD-inducible gene transcription. However, the tethering paradigm and molecular mechanisms employed by AHR and ARNT at ER-regulated genes remains to be determined. Secondly, thyroid hormone receptor/retinoblastoma-interacting protein 230 (TRIP230) interacts with ARNT and is a coactivator required for hypoxia-regulated transcription. The retinoblastoma protein (Rb) is a negative regulator of the cell cycle and also negatively regulates TRIP230 coactivator potential. Thus, Rb may influence ARNT transcription factor functions via TRIP230. Rb-loss in many solid tumours directly precedes the activation of HIF-regulated genes and correlates with increased angiogenesis and metastasis. As most solid tumours contain regions of hypoxia and only correlative data between HIF/ARNT activity and Rb-loss has been gathered, we have identified a need to rigorously examine the role of Rb-loss in concert with hypoxia in breast and prostate cancer models. In this thesis, I used siRNA technology to knockdown ARNT and AHR expression and found that TCDD-mediated disruption of ER-signalling is AHR-dependent and that ARNT is a coactivator in MCF7 cells and a corepressor in ECC1 cells. Additionally, I used siRNAs and shRNA technology in concert with microarray analysis in LNCaP prostate cancer cells and MCF7 breast cancer cells to delineate the role of the ARNT-TRIP230-Rb transcriptional complex in hypoxia-regulated transcription. I found that Rb-depletion in conjunction with hypoxia exacerbates HIF1-mediated transcription and promotes a more invasive and late stage phenotype in both breast and prostate cancer models. The molecular mechanisms and gene pathways described herein should prove useful for developing chemotherapies for late stage breast and prostate cancers.

This thesis investigates the design, fabrication, and characterization of a 3D printed electrochemical sensor as well as compact potentiostat circuits on Printed Circuit Board (PCB) for portable electrochemical sensing applications. Conductive 3D printing technologies are investigated as well as the advances in sensors and electronics applications. An optimized Directly Ink Writing (DIW) technique is adapted to a novel 3D-PCB fabrication platform using silver nanoparticle ink for electronics applications. An electrochemical device called potentiostat is designed based on an open source system. Its prototype is 3D printed on FR4 substrate. Using the same 3D platform, a lactate sensor which is composed of a 3-electrode is printed on the flexible substrate. Together, the 3D printed system demonstrates the electrochemistry test including cyclic voltammetry (CV) and amperometry. Results of this research demonstrate that 3D-PCB technology can significantly accelerate the fabrication process of conventional electronic, and merge its capability into electrochemical applications.

Cilia are microtubule-based organelles that emanate from the surface of most mammalian cell types. Motile cilia have well known roles in producing flow, while non-motile cilia play important sensory/signalling roles. Both forms are based on a similar axonemal structure, but ciliary motility requires additional components that conform to a regular arrangement along microtubules thought to be dictated by the protofilament ribbon (pf-ribbon). While pf-ribbon proteins have been implicated in ciliary motility, sensory/signalling functions in non-motile cilia have been less apparent. Although the ciliated organism Caenorhabditis elegans lacks motile cilia, orthologues of several ciliary pf-ribbon-associated proteins are present, including PACRG (Parkin co-regulated gene) and EFHC1 (EF-hand containing 1). In addition to their localisation to motile cilia, the pf-ribbon proteins show expression in neuronal cells of the brain where they may play important sensory roles. In particular, EFHC1 is mutated in the most common form of inherited epilepsy in humans and has been shown to be important for proper neuronal communication. This work investigates these motility-associated genes in C. elegans to dissect their sensory/signalling roles. We find that both PCRG-1 and EFHC-1 localise to a small subset of non-motile cilia in C. elegans, suggesting that they have been adapted to mediate specific sensory/signalling functions. We show that PCRG-1 influences a learning behaviour known as gustatory plasticity, where it is functionally coupled to heterotrimeric G-protein signalling. We also demonstrate that PCRG-1 promotes longevity in C. elegans by acting upstream of the lifespan-promoting FOXO transcription factor DAF-16 and likely upstream of insulin/IGF signalling, and that EFHC-1 also promotes longevity, suggesting shared signalling functions for these proteins. In addition, EFHC-1 modulates dopamine signalling where it is required for ciliary mechanosensation and regulating synaptic release of dopamine in cooperation with a voltage-gated calcium channel. Our findings establish previously unrecognised sensory/signalling functions for both PACRG and EFHC1 that may be important for neuronal communication in the human brain, where both proteins are known to be present. Furthermore, our work provides important clues for understanding and ultimately providing novel avenues for intervention of disorders such as epilepsy.

Urban densification is a form of development that has been seen as more sustainable compared to urban sprawl, typical for North American cities. Urban modeling has been extensively researched and mostly focused on urban sprawl using methods based on raster geographic information system (GIS) data and for two spatial dimensions (2D). The objectives of this thesis are the 1) development of a spatial index for 3D urban compactness; 2) development of geosimulation approaches for modeling spatio-temporal dynamics of changes in 4D for vertical urban growth; and 3) implementation and evaluation of the proposed approaches using geospatial datasets for regional and municipal spatial scales for the Metro Vancouver Region. Several modeling scenarios have been created to represent 3D urban growth development over space and time. The obtained results indicate that the proposed 4D geospatial approaches have potential to be used in urban planning.

Becoming a teacher involves more than the acquisition of a new set of skills and knowledge. It involves a change in one’s identity, and this change seems affected by tensions experienced during the teaching practicum. This multiple case study explores the points of tension experienced by 18 student teachers during practicum in a TESOL Certificate program in order to better understand transformations in one’s identity when one becomes a teacher. The study aims to address two questions: “What are the points of tension experienced by student teachers during their practicum and what are the discourses they engage in to talk about these tensions?” and “How can curricular and methodological changes in a TESOL program support the emergence of a transformational discourse when experiencing tensions?” The study uses a theoretical framework that conceptualizes the location of becoming a teacher in Bhabha’s (1998; 2008) Third Space, explores and extends Mezirow’s (1990; 1991; 2000; 2012) system of Transformational Education, and makes use of Bakhtin’s (1968; 1981) notions of dialogism and chronotopes of time, space, and threshold as constructs for creating, collecting, and interacting with the data. Freire’s (1970; 1974; 1992) notion of power underlies all aspects of the study from exploring the implications of inhabiting the role of teacher-as-researcher (Zeni, 2001) to the avoidance of prescriptive outcomes in program design. The study involved the collection of written and video data from three cohorts of student teachers throughout their four-month TESOL certificate program. A dialogical approach was applied to the analysis of the data that interweaves the experiences of the teacher-as-researcher with the experiences of the participants. The results indicate that student teachers experienced personal, interpersonal, knowledge, cultural, pedagogical, and methodological tensions, but more significantly, four discourses (blaming, explaining, questioning, problem-solving) were identified and explored for their transformational potential. The outcomes of the study indicate that some of the above discourses are more transformational than others. Suggestions and examples for developing a TESOL teacher education practice that provides time and space for transformational discourse to emerge are presented.

Adolescent women in South Africa face disproportionate HIV acquisition. In this context, evidence remains mixed on whether sexual self-efficacy (SSE)- one’s perceived control in decision-making regarding safe sex, predicts consistent condom use (CCU). Using cross-sectional survey data from 830 adolescent men and women aged 14-19 living in Soweto, South Africa, this thesis conducted gender-based analyses to examine determinants of high-SSE (study-alpha=0.75) and the association between high-SSE and CCU. Results revealed women have higher SSE than men. High-SSE was associated with CCU use for men, but not women. For women, high-SSE was associated with having an adult in the home, and no history of physical violence. Moreover, lower depressive symptomology among women was more predictive of CCU than SSE, indicating that gender-targeted HIV prevention interventions must move beyond individual-level determinants of behaviour to address socio-structural and relational factors influencing syndemic HIV risk among adolescent women in South Africa.