VictorJuiz/thesis huggingface dataset:
Enabling Power Wheelchair Mobility with Long-term Care Home Residents with Cognitive Impairments

For older adults, functional independent mobility is essential to well-being. Many care home residents have physical and cognitive impairments and use wheelchairs. Residents with difficulty self-propelling manual wheelchairs may benefit from power mobility; however, those with cognitive impairments may be precluded because of the potential for injury. My research goals were to apply novel power wheelchair technology to enable safe, independent mobility. Technology was developed to examine the value and implications of power mobility for residents with restricted mobility and mild or moderate cognitive impairments. The first study tested a prototype anti-collision wheelchair with a contact sensor skirt. Six single subject studies were completed. Distances travelled in manual and anti-collision wheelchairs were compared. Observational and interview data were collected. Focus groups (37 staff) and interviews (18 staff, six other residents, one spouse) were performed. Three of six residents were able or had potential to operate the prototype. One resident chose to use it beyond the study, and his mobility and well-being improved. Case analyses showed factors limiting prototype acceptance. Residents were unsatisfied with the appearance and slow speed, and found the interface frustrating to operate because of inadequate feedback. Social isolation and reduced autonomy restricted independence achievable with technology. Socialization and affective benefits of mobility were demonstrated in one case where prototype use was continually assisted. Residents and staff supported the anti-collision concept. On observation, the prototype compensated for absent or delayed responses of residents to obstacles below sensors and decreased injury risk. However, full sensor coverage of the environment was needed. The second study addressed acceptance and interface usability issues. A simulated collision-avoidance wheelchair with a multimodal feedback interface was evaluated. The interface provided audio, visual and haptic feedback to guide navigation away from obstacles. Through observations, interviews and questionnaires, five residents evaluated the device. High device acceptance and usability were found. The device was easy to use and assisted with performance of indoor mobility goals. Further research is necessary before power wheelchairs with new features are available for users; however, these results could play a fundamental role in shaping technology development and mobility interventions for this neglected population.

Keywords: older adult
nursing home
power mobility
wheelchair
long-term care home
cognitive impairment
mobility
dementia
safety
assistive technology
technology design
Advisor: Fernie, Geoff
Molecular and Functional Characterizations of Protein-protein Interactions in Central Nervous System

Many pathological processes are associated with excessive neurotransmitter release that leads to the over-stimulation of post-synaptic neurotransmitter receptors. Examples include excessive activation of glutamate receptors in ischemic stroke and hyper-dopaminergic state in schizophrenia and drug addiction. Thus, it would seem that simply antagonizing the involved receptors should be able to correct the pathological condition. In some instances, this strategy has been somewhat effective, such as with the use of dopamine D2 receptor antagonists as antipsychotics in the treatment of positive symptoms of schizophrenia despite severe side effect. However, clinical application of drugs antagonizing glutamate receptor in the treatment of stoke, although attracting intensive research effort, has been restricted by serious side effects caused by suppressing postsynaptic responses that are needed for normal brain function. As a consequence, it is important to develop novel therapeutics aiming at specific targets with minimized side effects. Numerous studies have suggested that the pathophysiology of neuropsychiatric disorders, drug addictions and stroke involves multiple neurotransmitter receptor systems such as the dopamine and glutamate systems. The activation or inhibition of one receptor can have cross-functional effect that will be better understood by investigating the functional and structural relationship between receptor systems. Thus, the present study has focused on characterizing receptor-receptor interactions associated with dopamine receptors and glutamate receptors, and to elucidate the physiological and pathological consequence of altered receptor interactions in schizophrenia, depression and ischemic stroke.

Keywords: dopamine receptor
glutamate
schizophrenia
depression
stroke
protein-protein interaction
Advisor: Liu, Fang
The Associate Teacher in the Preservice Practicum

This study explores the perspectives of associate teachers (also known as cooperating teachers, host teachers, mentor teachers) during the preservice practicum. The study was conducted over the span of one school year (2008-09) in one school district. Ten associate teachers consisting of primary, junior, and intermediate elementary teachers, who had been associate teachers during the 2008-2009 school year, were interviewed once for approximately one hour. Based upon the responses of the participants and related literature, the study reveals that overall associate teachers found the practicum experience to be positive. However, the varied responses also reveal that there is room for improvement. The findings indicate that the practicum experience would be greatly enhanced through allowing associate teachers more input into the preservice program, and increasing the collaboration amongst university supervisors, teacher candidates, and associate teachers. The findings also indicate that associate teachers seek a more defined and structured role description, which takes into account the reality of classrooms and their emotional work. Further, the study highlights the need for preservice programs to rebuild and promote professional practice that supports on-going learning for associate teachers. Suggestions for improvements in the preservice practicum are given as well as implications for future research. It is concluded that associate teachers need to be considered as real partners in preservice education, which can be achieved by preservice programs seeking programmatic coherence, rethinking institutional patterns and re-envisioning the role of associate teachers. It is suggested that a collaborative and innovative direction is required that takes into account the complex work of teachers and associate teachers.

Keywords: associate teacher
practicum
Advisor: Beck, Clive
Wavelength Conversion in Domain-disordered Quasi-phase Matching Superlattice Waveguides

This thesis examines second-order optical nonlinear wave mixing processes in domain-disordered quasi-phase matching waveguides and evaluates their potential use in compact, monolithically integrated wavelength conversion devices. The devices are based on a GaAs/AlGaAs superlattice-core waveguide structure with an improved design over previous generations. Quantum-well intermixing by ion-implantation is used to create the quasi-phase matching gratings in which the nonlinear susceptibility is periodically suppressed. Photoluminescence experiments showed a large band gap energy blue shift around 70 nm after intermixing. Measured two-photon absorption coefficients showed a significant polarization dependence and suppression of up to 80% after intermixing. Similar polarization dependencies and suppression were observed in three-photon absorption and nonlinear refraction. Advanced modeling of second-harmonic generation showed reductions of over 50% in efficiency due to linear losses alone. Self-phase modulation was found to be the dominant parasitic nonlinear effect on the conversion efficiency, with reductions of over 60%. Simulations of group velocity mismatch showed modest reductions in efficiency of less than 10%. Experiments on second-harmonic generation showed improvements in efficiency over previous generations due to low linear loss and improved intermixing. The improvements permitted demonstration of continuous wave second-harmonic generation for the first time in such structures with output power exceeding 1 µW. Also, Type-II phase matching was demonstrated for the first time. Saturation was observed as the power was increased, which, as predicted, was the result of self-phase modulation when using 2 ps pulses. By using 20 ps pulses instead, saturation effects were avoided. Thermo-optically induced bistability was observed in continuous wave experiments. Difference frequency generation was demonstrated with wavelengths from the optical C-band being converted to the L- and U-bands with continuous waves. Conversion for Type-I phase matching was demonstrated over 20 nm with signal and idler wavelengths being separated by over 100 nm. Type-II phase matched conversion was also observed. Using the experimental data for analysis, self-pumped conversion devices were found to require external amplification to reach practical output powers. Threshold pump powers for optical parametric oscillators were calculated to be impractically large. Proposed improvements to the device design are predicted to allow more practical operation of integrated conversion devices based on quasi-phase matching superlattice waveguides.

Keywords: nonlinear optics
second-harmonic generation
difference frequency generation
optical Kerr effect
photonic integrated circuit
semiconductor
second-order optical nonlinearity
quasi-phase matching
parametric conversion
superlattice
Advisor: Aitchison, J. Stewart
Helmy, Amr S.
Design of a Novel Serum-free Monolayer Differentiation System for Murine Embryonic Stem Cell-derived Chondrocytes for Potential High-content Imaging Applications

Cartilage defects have limited capacity for repair and are often replaced by fibrocartilage with inferior mechanical properties. To overcome the limitations of artificial joint replacement, high throughput screens (HTS) could be developed to identify molecules that stimulate differentiation and/or proliferation of articular cartilage for drug therapy or tissue engineering. Currently embryonic stem cells (ESCs) can differentiate into articular cartilage by forming aggregates (embryoid body (EB), pellet, micromass), which are difficult to image. I present a novel, single-step method of generating murine ESC (mESC)-derived chondrocytes in monolayer cultures in chemically defined conditions. Mesoderm induction was achieved in cultures supplemented with BMP4, Activin A or Wnt3a. Prolonged culture with sustained Activin A, TGFβ3 or BMP4 supplementation led to robust chondrogenic induction. A short pulse of Activin A or BMP4 also induced chondrogenesis efficiently while Wnt3a acted as a later inducer. Long-term supplementation with Activin A or with Activin A followed by TGFβ3 may specifically promote articular cartilage formation. Thus, I devised a serum-free (SF) culture system to generate ESC-derived chondrocytes without the establishment of 3D cultures or the aid of cell sorting. Cultures were governed by the same signaling pathways as 3D ESC differentiation systems and limb bud mesenchyme or articular cartilage explant cultures. I am also in the process of creating a Col2a1 promoter-controlled, Cre-inducible reporter cell line to be used in my SF culture system using the Multisite Gateway® cloning technology. ESCs undergoing chondrogenic differentiation can be identified and quantified in HTS via the expression of fluorescent proteins. In addition, this transgenic line can be used to isolate ESC-derived chondrocytes as well as their progeny via cell sorting or antibiotic selection for in-depth characterization. The modular design of my construct system allows transgenic lines to be generated using various promoters of chondrogenic marker genes to perform parallel HTS analyses.

Keywords: embryonic stem cells
chondrocytes
serum-free
monolayer
Advisor: Stanford, William L.
Periodic Mesoporous Organosilica and Silica

Periodic mesoporous material is a class of solids that possess periodically ordered pores with sizes of 2–50 nm. After a brief introduction to the synthesis, structure, property and function of periodic mesoporous materials in general in Chapter 1, a specific type of periodic mesoporous material, periodic mesoporous organosilica (PMO), is examined in detail in Chapter 2. Chapter 3 and Chapter 4 focus on the application of periodic mesoporous organosilica as low-dielectric-constant (low-k) insulating materials on semiconductor microprocessors. Specifically, Chapter 3 introduces a vapor-phase delivery technique, vacuum-assisted aerosol deposition, for the synthesis of PMO thin films; Chapter 4 studies one property crucial for the application of low-k PMO in detail—hydrophobicity. The focus of Chapter 5 turns to a novel sandwich-structured nanocomposite made of periodic mesoporous silica and graphene oxide. In Chapter 6, progress towards the synthesis of periodic mesoporous quartz is summarized. A conclusion and an outlook are given in Chapter 7.

Keywords: Porous Materials
thin films
Low dielectric constant
inorganic-organic hybrid
Advisor: Ozin, Geoffrey Alan
Stigma Resistance: Exploring the Experiences of Young People at Risk for Psychosis Through Photo Elicitation

The discovery that it is possible to identify an individual before the onset of first episode psychosis and that treatment may prevent or delay onset have led to a proliferation of early intervention clinics designed to intervene before symptoms of psychosis have fully appeared. Early intervention has generated considerable debate, given the risks associated with intervening and that the majority of those identified will never develop full-blown psychosis. Despite potential stigmatizing effects, little is known about young people’s views regarding the favourable and/or adverse consequences of early intervention. This research examines the experiences and meaning of illness in young people identified as being at ultra high risk for psychosis and participating in a psychological intervention program. Specifically, the study uses photo elicitation to explore how participants construct and interpret their experiences, and the impact an at risk label has on their sense of self, identity, and social relationships. Five young people were invited to photograph their daily experiences at home, at school, and in the community. The participants and I then analyzed the photographs together in a photo elicitation interview. I further analyzed the visual and textual data from an interactionist perspective, exploring the concept of stigma and its relationship to young people’s experiences. Visual and narrative data revealed that young people reject their at risk status and redefine their experiences to fit with more acceptable and familiar notions of health. Participants are conscious of the stigma associated with psychosis and actively undertake strategies of resistance to avoid stigmatization and uphold a normal self conception and social impression. Photo elicitation provided insight and understanding into the experiences of young people at risk for psychosis that were not available through more traditional methods. The results from this study support the call for a reconsideration of the psychosis risk paradigm. There is a need to increase awareness about the power of diagnostic information and the labeling process. Non-specialized settings such as schools and community health centres may offer more appropriate environments for mental health monitoring and intervention.

Keywords: early psychosis
adolescence
qualitative methods
photo elicitation
stigma
Advisor: Boydell, Katherine
The Role of ShcA Phosphotyrosine Signaling in the Myocardium

Tyrosine kinases (TK) are important for cardiac function, but their downstream targets in the adult heart have yet to be established. The ShcA docking protein binds specific phosphotyrosine (pTyr) sites on activated TKs through its N-terminal PTB and C-terminal SH2 domains and stimulates downstream pathways through motifs such as pTyr sites in its central CH1 region. To explore the role of this TK scaffold in the adult heart, we generated a myocardial-specific knockout of murine ShcA (ShcA CKO). Such mice developed a dilated cardiomyopathy phenotype involving impaired systolic function with enhanced cardiomyocyte contractility. This uncoupling of global heart and intrinsic myocyte functions was associated with altered perimysial collagen and extracellular matrix complicance properties, suggesting disruption of mechanical coupling. In vivo dissection of ShcA signaling properties revealed that selective inactivation of the PTB domain in the myocardium had effects resembling those seen in ShcA CKO mice, while disruption of the SH2 domain caused a less severe cardiac phenotype. Downstream signaling through the CH1 pTyr sites was dispensable for baseline cardiac function, but necessary to prevent adverse remodeling after hemodynamic overload. Therefore, ShcA mediates pTyr signaling in the adult heart through multiple distinct signaling elements that control myocardial functions and response to stresses.

Keywords: adaptor protein
cardiovascular
Advisor: Pawson, Tony
Backx, Peter
Evaluating T-cell Immunity in HCV/HIV Co-infection

Due to shared routes of transmission, co-infection with Hepatitis C (HCV) and Human Immuno-deficiency Virus (HIV) has become prevalent worldwide, with approximately one-third of all HIV-infected individuals and about 10% of all HCV infected individuals in North America being co-infected with the other virus (1). Recent advances in HIV treatment have increased the life expectancy of HIV-infected patients, resulting in HCV-associated disease to develop into a major cause of morbidity and mortality among the co-infected population. HIV is consistently shown to have a negative effect on different aspects of HCV disease, from increased HCV RNA levels (2) to aggravated liver fibrosis and more rapid progression to cirrhosis and end-stage liver disease (3). The host immune responses play a major role in not only controlling HCV infection, but also in causing hepatic inflammation and damage. Despite major advances in the understanding of the pathogenesis of these two infections, the mechanisms underlying the role of immune responses in more rapid progression of HCV disease in HCV/HIV co-infection is not quite clear. This thesis is generated based on an investigation to understand why HIV infection worsens HCV pathogenesis. This question is addressed throughout this thesis from different immunological aspects, with a focus on the function of T-cells. I have demonstrated that in HCV/HIV co-infection, functional HIV-specific T-cells accumulate in the liver and produce an array of cytokines, including INF- and TNF-, which may represent a bystander role for HIV in the aggravation of HCV-induced liver damage. My data also demonstrate that co-expression of two defined T-cell exhaustion markers, Tim-3 and PD-1 may play a significant role in HCV-specific T-cell dysfunction, in the setting of HIV co-infection. Both total and HCV-specific peripheral T-cells co-express Tim-3 and PD-1 in significantly higher frequencies, compared to HCV mono-infection. In co-infection, HCV-specific CD8+ T-cells showed greater frequencies of Tim-3/PD-1 dual-expression than those being HIV-specific, indicating a greater degree of exhaustion in the former. Additionally, I demonstrated that some HIV mono-infected individuals may contain CD8+ T-cells that cross-recognize two defined HLA-A2-restricted epitopes within the HIV and HCV proteome, the HIV-Gag: SLYNTVATL and HCV-NS5b: ALYDVVSKL. This T-cell cross-reactivity was further elaborated in the context of HCV/HIV co-infection, demonstrating that degeneracy of HIV-specific T-cells may play a role in the immuno-pathology of co-infection. Altogether, these data could be integrated into the foundation of potential mechanisms involved in the immunopathogenesis of HCV/HIV co-infection, and be applied to further investigation in basic science and clinical studies in this field.

Keywords: Immunology
Infectious Disease
Advisor: Ostrowski, Mario
A Chinese Civil Society in the Making? Civic Perceptions and Civic Participation of University Students in an Era of Massification

Chinese higher education has achieved a remarkable expansion in recent years but few studies have examined the civic perceptions and civic participation of contemporary university students. This study aims to fill the gap in the existing literature by accomplishing four main goals: first, to investigate how students view citizenship, civic issues, and civil society; second, to examine how they participate in civic activities, both on and off campus; third, to understand how their civic attitudes and behaviours are being influenced by society, university and family, also by such factors as formal citizenship education curricula, informal educational experiences and the mass media; and fourth, to analyze the impact of higher education expansion on civil society in China. This study adopted a mixed methods approach, and combined findings from a large-scale national student survey across 12 universities and 34 face to face interviews conducted in 3 selected institutions among the 12 that were surveyed. The conceptual framework drew upon social capital theory and both ecological and cognitive psychological theories to generate two analytic frameworks for analyzing the quantitative and qualitative data. The major findings were: (1) university students demonstrated strong patriotism, and a serious commitment to social justice and civic participation, which was partly the result of the distinctive form of citizenship education they received in the Chinese context; (2) half of the survey participants were found to be inactive participants in civic activities, which showed a disconnect between their civic attitudes and civic behaviours; (3) higher socio-economic status (SES) was associated with more active civic participation; (4) the mass media, especially the Internet was found to have a profound impact on students’ civic perceptions; (5) interview participants in the three qualitative case institutions revealed distinctive patterns of civic engagement, which confirmed the importance of university environment, policy, history and culture on student civic participation and citizenship development. This study has made a significant contribution to the existing literature on citizenship issues in contemporary Chinese universities. It has also added to current knowledge on trends of civil society development and the democratization process in China, from the perspective of university students.

Keywords: Civil Society
Higher Education
Civic Perceptions
Civic Participation
Citizenship Education
University Students
Middle-Class
China
Advisor: Hayhoe, Ruth