Queen's Graduate Theses and Dissertations

This is a collection of the Queen's University Masters Degree and PhD Theses and Dissertations. Submissions are limited to officially registered Queen's University graduate students, only.


Recent Submissions

Now showing 1 - 5 of 8189
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    Nurturing Inclusive Urban Futures: Valuing the Contributions of Community Organizations in Ontario Cities
    Geography and Planning; Cameron, Laura Jean
    This dissertation investigates the experiences of community organizations in three Ontario cities— Cornwall, Kingston, and Ottawa—as they grapple with building municipal relationships and navigating community development processes in their cities. Community organizations, informal collectives formed around shared identity or goals, play a vital role in contributing to the liveliness and wellbeing of urban communities. Regardless of their varied socio-spatial contexts and mandates, which include community support, activism, inclusion, arts, and heritage activities, these organizations often extend their efforts to fulfill essential care work for their communities and address service deficiencies for underserved populations. Yet, they are frequently underrecognized and unsupported by municipalities, who do not understand or value their contributions. Community organizations encounter significant logistical, spatial, financial, and operational challenges that place their communities and those they support in positions of precarity. These issues stem from structural oppression embedded within neoliberal paradigms and urban power systems. These systems of oppression limit municipalities’ purported attempts to engage in equitable, diverse, and inclusive community development practices. The findings of this dissertation are grounded in a range of voices, centering the geographical imaginations and experiences of participants through various research communication strategies. In line with the principles of critical praxis-oriented research, this study engages in responsive knowledge mobilization through the creation of alternative research communication formats including zine work and report creation, being attentive to the audiences that research might benefit. This approach ensures that the research not only contributes to academic discourse but has practical implications for the communities it studies. It considers the potential value of these findings for municipalities striving to create more inclusive communities and brings forward the importance of recognizing and addressing the challenges faced by community organizations in their efforts to engage in care work and create a sense of place and belonging in their cities.
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    Enabling Neutrinoless Double Beta Decay in the SNO+ Experiment through the Deployment and Study of Liquid Scintillator
    Physics, Engineering Physics and Astronomy; Chen, Mark
    The search for neutrinoless double beta decay is among the most pressing scientific objectives at this time. If observed, this hypothesised process would not only revolutionise several fields of physics, but our fundamental understanding of the universe itself. The SNO+ experiment is a kilotonne-scale neutrino detector with the primary goal of searching for neutrinoless double beta decay in tellurium-130, and this thesis recounts the studies and efforts that have enabled this search capability. A new liquid scintillator was developed for the SNO+ detector to facilitate this search. To accommodate and understand this target medium, the detector hardware was upgraded, and measurements of the scintillator were undertaken to build a precise detector model. A novel chemical process was developed to stably load the liquid scintillator with tellurium, and the hardware to facilitate this process was installed. Due to the rarity of the decay, trace amounts of contamination could cause insurmountable backgrounds. As such, efforts were undertaken to ensure the purity of the liquid scintillator during deployment into the detector. The first analysis of the detector when fully filled with liquid scintillator was performed, providing a characterisation of the scintillator prior to the addition of tellurium. The purity of the liquid scintillator within SNO+ was verified to be sufficient to perform a competitive search. Furthermore, all hardware and techniques are now in place to proceed with the loading of tellurium into the liquid scintillator. This work has thus placed SNO+ in the position to be the next major global experiment to initiate a search for neutrinoless double beta decay.
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    A Study of Metal Ion Migration in Oil Paint Films with Iron Oxide, Cobalt, and Organic Pigments
    Art Conservation; Murray, Alison; Smithen, Patricia; Fuster López, Laura
    Metal soap formation and metal ion migration are two drying phenomena observed in historical and modern oil paintings. Conservation professionals have observed that the formation of metal soaps in oil paintings can be problematic for their care, and these metalorganic compounds have been linked to cracking and delamination on the surfaces of paintings. Metal ion migration can facilitate this process by the transfer of metal ions into adjacent paint layers which may induce metal soap formation in paints that would otherwise not undergo this process. The focus of this thesis was to determine whether metal ion migration and metal soap formation can be observed during the intial stages of the curing process of oil paint films. Laboratory samples consisting of paint films of a selection of colours and pigment content were studied using analytical methods including attenuated total reflectance-Fourier-transform infrared spectroscopy (FTIR-ATR), portable X-ray fluorescence spectroscopy, and environmental scanning electron microscopy coupled with energy dispersive spectroscopy (ESEM-EDS), along with two other methods, the scribe test and the percent weight change tests. In particular, the results from the scribe test strongly suggests that interactions between adjacent paint films occur and can affect the drying times of individual paint types. Analyses conducted on the laboratory samples served to study the drying behaviour of paint films early in the paint-curing process in the immediate period following their initial casting. While metal ion migration and metal soap formation were not confirmed to have taken place through instrumental methods, interactions between different paint types were found to have occurred through the scribe and weight tests. A case study was also undertaken as part of this study to understand the long-term drying behaviour of oil paints better. Two paintings by the French-Canadian artist Jean-Paul Riopelle from the Agnes Etherington Art Centre were analyzed using FTIR-ATR, scanning XRF, and ESEM-EDS. Two crack patterns observed on the surfaces of the paintings could be attributed to the presence of cobalt and calcium in the paint layers.
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    Visible Light Stimulated Degradable Drug Release Devices for Ocular Delivery
    Chemical Engineering; Amsden, Brian
    Delivery of therapeutics including biopharmaceuticals and corticosteroids to ocular tissue has been a challenge due to the complex anatomy of the eye. There is a need to develop novel ophthalmic drug delivery systems to provide a prolonged therapeutic level of drugs and enhance bioavailability. Photoresponsive delivery systems provide spatiotemporal control of their properties in a non-invasive way, which may improve efficacy and reduce drug side effects when compared to existing approaches. In this work, visible-light degradable polymers were designed and investigated for their potential for the preparation of ocular delivery devices. The designed visible-light degradable polymer was derived from poly(5-hydroxytrimethylene carbonate) (PHTMC). The pendant hydroxyl groups of the PHTMC were protected by visible light-labile [7-(diethylamino)coumarin-4-yl]methyl (DEACM). Upon photo-irradiation, the DEACM group is removed, leaving PHTMC which degrades rapidly via intramolecular cyclization. In this work, a visible-light stimulated degradable hydrogel system and a micelle system based on DEACM protected PHTMC were created to provide sustained and controlled drug delivery. The hydrogel system was designed for intravitreal delivery of neurotrophic factors. The hydrogel is capable of providing sustained release of highly bioactive protein with a minimal burst effect and is ultimately degradable when triggered by visible light. The hydrogels exhibited a photo-triggered degradation profile. Hydrogels formed with 4a-PEG-thiol-5k provide sustained release of bioactive cytochrome as a model protein drug for 7 weeks with a minimal burst effect. A photo-responsive release profile was achieved by triggering hydrogel degradation, which altered the drug release rate on demand. A photo-degradable micelle formulation was designed for drug delivery, whose release profile can be remotely controlled by visible light irradiation to enable on-demand delivery. The micelle system was formed by a polycarbonate-based amphiphilic diblock copolymer, whose hydrophobic block was based on DEACM protected PHTMC. Upon the removal of these protecting groups by photo-irradiation, the micelles undergo structural disruption, leading to the release of the payload. The removal of DEACM would also deprotect the pendant hydroxyl groups of PHTMC, leading to PHTMC backbone degradation via iii intramolecular cyclization. To demonstrate proof-of-principle, the release of Nile Red and dexamethasone was examined. These approaches represent the first design as ocular delivery devices and have demonstrated great potential. While further improvements may be needed to enhance certain features, the preliminary assessments have been promising.
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    Neuroscience Studies; Scott, Stephen; Baharnoori, Moogeh
    Multiple Sclerosis (MS) is a chronic neuroinflammatory disorder characterized by multifocal inflammation and demyelination throughout the central nervous system, leading to widespread motor, cognitive, and/or sensory dysfunction. The current gold standard for assessing disability progression in MS is the Expanded Disability Status Scale (EDSS), ranging from 0, a normal neurological exam, to 10, signifying death due to MS (Kurtzke, 1983). Yet, this disability scale predominantly focuses on mobility and lower limb motor function with a limited assessment of upper limb function and cognition (Bethoux et al., 2016). Importantly, the EDSS lacks the evaluation of complex tasks involving simultaneous cognitive and motor function. In this study, we use the Kinarm robotic platform to evaluate upper limb sensory, motor, and cognitive function in Persons with MS (PwMS) and compare it to standard clinical assessments. We hypothesize that individuals with MS will exhibit greater impairments in complex tasks involving cognitive and motor processing, and there will be a strong correlation in performance across robot-based and traditional variants of related tasks. This research builds upon the previous Kinarm feasibility study conducted by our group (Simmatis et al., 2020), with a larger combined cohort of 65 patients with EDSS scores ranging from 0 to 4 (mild to moderate impairments). PwMS complete traditional clinical assessments in addition to 7 Kinarm Standard Tests (KST) including 1) basic sensory and motor performance and 2) complex dual processing cognitive-motor tasks. Our results identified 64.6% (42/65) of PwMS as impaired on at least one task. Basic motor tasks revealed impairment rates ranging from 12.3% to 16.92%, whereas complex tasks with additional cognitive challenges exhibited higher impairment rates from 21.5% to 30.7%. Concurrent validity was established through moderate correlations and consistent levels of impairment between the Kinarm assessments and the traditional clinical assessments. Importantly, these findings highlight the limitations of the EDSS in capturing cognitive and motor impairments in more complex tasks that do not align with the expected disability progression suggested by the EDSS. This study highlights the Kinarm’s ability to quantify a range of cognitive and motor impairments in PwMS.

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