title: Riding the waves: The formation and evolution of vertical bending waves in Milky Way-like disc galaxies

contributor: Physics, Engineering Physics and Astronomy

subject:
Galaxy dynamics
Milky Way
Gaia
Bending waves
Disc dynamics
Vertical waves
N-body simulations
Disc galaxies

abstract:
In this thesis we study the dynamics of vertical (bending) waves in Milky Way-like disc galaxies. The main goals of the thesis are to form a coherent picture for the formation and evolution of bending waves using three-dimensional $N$-body simulations, develop tools and machinery to aid in the study of vertical waves in both simulations and astrometric surveys, and to make predictions for what we might see in the analysis of Gaia data.

The hallmark simulations presented in this thesis evolve a two-component disc embedded in smooth and `clumpy' haloes, where the latter contains multiple orbiting substructure. One of our main conclusions is that vertical (bending) waves should be generic, long-lived features of massive discs that can form with and without provocation from external agents, though the predominant type of vertical wave induced by the latter is dependent on the perturber's orbital parameters. Furthermore, we find that bending is a property almost exclusive to kinematically cooler (thin disc) stellar populations.

In our simulations bending waves manifest as variations in mean vertical displacement and bulk vertical motions, that together behave largely as simple monochromatic plane waves. At intermediate radii they appear as tightly wound, short-wave corrugations that match smoothly onto the warp near the edge of the disc. By way of Fourier and spectral analyses, based on classical studies of in-plane density waves and further developed in this thesis for the study of vertical waves, we find that in general the waves are a superposition of modes that comprise two main branches on the radius-rotational frequency plane.

The preeminent result of this thesis is a novel sequence of events describing the life-cycle of bending waves, which involves excitation, dispersion, phase-wrapping or shearing across the disc, self-gravitating wave-like action, and disc heating. This conclusion is largely borne out of the comparison between frequency power spectra of waves in our simulations with predictions from linear perturbation theory, and suggests that the wave-like features in astrometric surveys such as Gaia may indicate the existence of long-lived modes of a dynamically active disc in addition to perturbations from recent disc-satellite interactions.

abstract: PhD


title: Investigating electromechanical coupling between membrane crystal materials and superconducting microwave resonators

rights: Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada

rights: ProQuest PhD and Master's Theses International Dissemination Agreement

rights: Intellectual Property Guidelines at Queen's University

rights: This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

subject:
Electromechanics
Optomechanics
Quantum Optics
Cavity Quantum Electromechanics
Mechanical Resonator
Superconducting Resonator
MEMS
NEMS
2D material
Optical Colour Analysis
Nanofabrication
Sideband Cooling

abstract:
This work studies the use of two-dimensional (2D) crystal materials as mechanical elements in an electromechanical resonant system. 2D materials form crystals that have strong in-plane bonds but weak out-of-plane bonds, allowing for their separation into thin planar layers. Graphene and niobium diselenide are two such materials studied, and they are suspended as electrodes in a parallel plate capacitor. When this capacitor is integrated into an electromagnetic resonant circuit, any movement of this suspended material will greatly effect the resonance frequency of the circuit. Measurement of the resonance frequency allows a dispersive readout of the motion. This system of two coupled harmonic oscillators has the potential to demonstrate strong coupling where the two must be described in a combined state. The light-matter interactions can pave the way to quantum-limited measurement of position and perhaps a means to control, measure, and store qubit information in quantum computing systems.

A method to fabricate and optically characterize suspended capacitor devices was developed with the ultimate goal of testing in a dilution refrigerator. Low loss superconducting aluminum integrated circuits were designed and made with these capacitors to allow microwave readout and interaction with the motion of the vibrating membrane materials. Predictions on the microwave electromechanical sideband output shows feasibility for future cryogenic measurements of the 2D crystal motion.

abstract: PhD


title: Asymmetric matching allele models: imperfect matching, stability and the impact of mutation

contributor:
Day, Troy
Mathematics and Statistics

subject:
Mathematics
Biomathematics
Host
Parasite
Coevolution
Asymmetric matching
Asymmetric matching alleles
Matching alleles
Dynamical systems
Local stability analysis
Difference equations

abstract: Asymmetric matching alleles models assume that each parasite genotype specializes on a matching host genotype to a different degree. We study system behavior of a single locus di-allelic asymmetric matching alleles model. Inline with other investigators, we make the counter-intuitive observation that intermediate levels of asymmetric matching lead the parasite genotype with the lowest fitness in it's matching host genotype to, on average, be at majority frequencies. The parasite genotype with the highest fitness in its matching host keeps the frequency of this matching host low, which keeps its own frequency low. Further analysis of our asymmetric matching alleles model yields three novel predictions. To begin, a facet of asymmetric matching whose study has been avoided involves the fitness implications of imperfect matching. Imperfect matching permits reduced fitness for parasites enacting a cross infection. Under imperfect matching, increasing the relative fitness for cross infections lowers the level of asymmetric matching required for a parasite genotype to have the highest fitness when infecting any host, which would drive this parasite genotype to or near fixation. Having this high fitness parasite genotype near fixation yields a selection pressure within the host population to mitigate parasite success by having a high frequency of the cross infection host genotype. The second model prediction demonstrates that asymmetric matching can lead to increased system stability by dampening oscillations and lowering the amount of mutation needed for stability. Finally, our analysis predicts that the magnitude of antagonism between parasites and hosts has a large effect on the genetic composition and system behavior of the host-parasite system. We find that parasite and host mutation contribute differently to these antagonism-mediated effects. Overall, studying the single locus system behavior of asymmetric matching allele models should allow for better informed future studies concerning the effects that asymmetric matching has on; polymorphism incidence, recombination rate and mutation rate evolution.

abstract: M.Sc.


title: Reaction of CS2 and CO2 with Amidines and Guanidines

contributor:
Jessop, Philip
Chemistry

subject: CS2, CO2, Amidines, and Guanidines

abstract:
Neutral organic bases such as amidines and guanidines are very useful in studies of the reactivity of heterocumulenes such as carbon disulfide (CS2) and carbon dioxide (CO2) to build C-C or C-N bonds. Reaction of amidines with CS2 in the absence of water and without adding desulfurization reagents or solvents is less documented. In this research I have investigated different types of sulfur and nitrogen containing products obtained upon reaction of carbon disulfide with cyclic and acyclic amidines. The reactivity behaviour and the resulting products depend on the structure of the starting amidines. Our observations for the contrasting reactivity were supported by calculations of the free energy of the reaction.

     1,4,5,6-Tetrahydropyrimidine derivatives, as examples of cyclic amidines, follow different reactivity compared to acyclic amidines. They also follow different patterns of reaction with CS2 depending on their structures. Possessing an N-H bond allows the cyclic amidine to form a dithiocarbamate salt {[BH+] [(B-CS-2)-(H)]}, where B is the starting amidine, analogous to those formed by secondary amines [R2NH2][R2NCO2] and [R2NH2][R2NCS2] with CO2 or CS2, respectively. If the molecule does not possess an N-H bond then observed reactivity depends on whether there is a methylene alpha to the amidine carbon. Having such a methylene group promotes the formation of trithioanhydride. A tetrahydropyrimidine having neither an N-H bond nor an alpha methylene forms an unstable zwitterionic adduct (B-CS2).

     The acyclic amidines and their analogues (e.g., acetamidines and TMG) have the ability to rotate around the (C=N) bond to form a four-membered cyclic transition state which cleaves to form two molecules: isothiocyanates (RNCS) and thioacetamide or tetramethylthiourea (TMTU) in the case of the guanidine. Such rotation cannot happen in cyclic amidines due to their rigidity.

        Alkylation reactions performed on the products of the reaction of 1,4,5,6-tetrahydropyrimidines and CS2 lead to the formation of dithiocarbamate salts and dithiocarbamate esters and other interesting compounds. Compounds structurally related to these products have significant medical applications. The alkylation products also serve to confirm the proposed structures of some of the products obtained from the initial reactions with CS2.

      Both cyclic and acyclic amidines and their analogues were exposed to different CO2 pressures (1 or 60 bar) under various temperatures (room temperature or 60 oC) in order to form carbamic acid or carbamate products, but either bicarbonate salts or no reactivity were observed.

abstract: PhD


title: X-ray photoelectron spectroscopy study of the interaction of N-heterocyclic carbenes with polycrystalline copper surfaces

contributor:
Horton, J.Hugh
Chemistry

subject: Copper SAMs NHCs oxidized XPS Surfaces

abstract: The interaction of organic molecules with metal surfaces to form self-assembled monolayers (SAMs) has been extensively investigated. The formation of SAM on metal surfaces has potential applications in microelectronics, chemical sensing and metal protection in which the SAM quality and stability play critical roles. Thiols are the most widely used in SAM technology. However, the metal-thiolate bond is rapidly oxidized under ambient conditions. Therefore, new ligands were investigated to replace thiols, namely N-heterocyclic carbenes (NHCs). NHCs are well known as ligands for transition metal complexes. Consequently, they are strong candidates for SAM formation on transition metal surfaces. So far, NHCs have been applied to gold surfaces, which produced films with remarkable stability. However, less is understood about the interaction of NHCs with other transition metals. One particularly interesting transition metal is copper, which has significant applications in electronics, heat transfer, etc. Copper is cheaper than gold, but it is easily oxidized and corroded in different media, thus finding a method of preventing this oxidation is very important. Here, we present a study of NHC interactions with clean and oxidized copper surfaces at different temperatures. Detailed X-ray photoelectron spectroscopy (XPS) experiments have been carried out, using both a standard XP spectrometer at fixed X-ray energy, and experiments at variable photoelectron energies carried out at the Canadian Light Source synchrotron. The result shows that exposing the oxidized copper surface to the NHC solution led to a complete removal or reduction of the oxide layer from the surface, followed by a SAM formation on the reduced surface. Evidence from mass spectrometry shows copper and oxygen complexes in the solution, which proves the ability of the NHCs to interact with the oxide layer and remove it from the surface. Further experiments carried out at varying temperature and NHC exposure times have revealed further details on the mechanism of carbene reaction with the surface. These results show promise in gaining a more fulsome understanding of the dynamics of NHC interactions with Cu, with a view to designing surfaces that are passivated towards oxidation.

abstract: PhD


title: Modeling Subfornical Organ Neurons

contributor:
Ferguson, Alastair
Neuroscience Studies

subject:
subfornical organ
hodgkin-huxley
neuron model
model
bursting

abstract: Subfornical organ (SFO) neurons exhibit heterogeneity in ionic current expression and spiking behaviour, where the two major phenotypes appear as tonic and burst firing. Insight into the mechanisms behind this heterogeneity is critical for understanding how the SFO, a sensory circumventricular organ, integrates and selectively influences autonomic nervous system, endocrine, and behavioural function. To integrate efficient methods for investigating this heterogeneity, we built a single-compartment, Hodgkin-Huxley type model of an SFO neuron that is parameterized by SFO-specific in vitro voltage-clamp data. The model accounts for the individual membrane potential distribution and spike train variability of tonic and burst firing SFO neurons. Analysis of model dynamics confirms that a persistent Na+ and a Ca2+ current are required for burst initiation and maintenance, and suggests that a slow-activating K+ current may be responsible for burst termination in SFO neurons. Additionally, the model suggests that heterogeneity in current expression and subsequent influence on spike afterpotential underlies the behavioural differences between tonic and burst firing SFO neurons. The use of our model in coordination with in vitro electrophysiology experiments, provides a platform for explaining and predicting the response of SFO neurons to various combinations of circulating signals, as demonstrated by our preliminary investigation of inflammatory and cardiovascular signal integration. Our model predicts that 24-hr incubation in tumor necrosis factor alpha, an inflammatory cytokine, will result in the potentiation of SFO neuron excitability in response to angiotensin II. This prediction provides a potential mechanism to support previous findings that inflammation may be potentiating angiotensin II actions in the SFO. Future studies will work to further elucidate the mechanisms underlying the integration of physiologically important signals in the SFO.

abstract: M.Sc.


title: Essays on Accounting Consistency

contributor:
Welker, Michael
Business

subject:
Accounting Consistency
Analyst Behavior
Accounting Policy Changes
SFAS No. 154

abstract:
This study develops a measure of accounting consistency based on the idea that the accounting function is the accounting measurement system that managers use to translate economic events to financial statements. When a firm uses accounting policies and estimates consistently, one can estimate its current-year earnings accurately by applying prior years’ accounting function to the current-year economic events. Empirically, I find that my accounting consistency measure is positively associated with analyst following and forecast accuracy, and negatively associated with analyst forecast dispersion. To further test the effect of accounting consistency on analyst behavior, I examine the impact on analyst forecasts of accounting policy changes, which reduce accounting consistency. I find that accounting policy changes decrease analyst forecast accuracy and increase analyst forecast dispersion. These results suggest that accounting consistency benefits financial statement users.
	This study also examines the impact of SFAS No. 154, Accounting Changes and Error Corrections, on the information processing of financial analysts. SFAS No. 154 is issued to improve accounting consistency between periods when there is a voluntary accounting policy change. Using 969 voluntary accounting policy changes from 1994 to 2015, I find that the impact of voluntary accounting policy changes on analyst forecast accuracy and dispersion is weaker under SFAS No. 154 than under the predecessor standard, APB Opinion No. 20, indicating that SFAS No. 154 improves financial reporting usefulness by enhancing accounting consistency. This finding provides evidence for standard setters and regulators regarding the benefits of SFAS No. 154 adoption.

abstract: PhD


title: Tumor necrosis factor alpha influences the excitability of subfornical organ neurons and potentiates angiotensin II-induced calcium activity

contributor:
Ferguson, Alastair V
Neuroscience Studies

subject:
tumor necrosis factor apha
subfornical organ
angiotensin II
neuron
calcium

abstract: Cardiovascular disease is a leading cause of mortality worldwide. Progress has been made in diagnosing and treating this condition, however the mechanisms by which it develops have yet to be fully elucidated. Accumulating evidence suggests that inflammation plays an important role in cardiovascular disease. Cytokines are elevated in patients with hypertension and heart failure, as well as in animal models of these conditions. Tumor necrosis factor alpha (TNFα), a cytokine, has been shown to increase blood pressure and sympathetic output, and it is critical in the development of hypertension. It has been determined that the subfornical organ (SFO) of the central nervous system mediates the effects of TNFα. Knockdown of the TNFα receptor in the SFO ameliorates sympathoexcitation following heart failure, further suggesting a mechanism by which TNFα acts in the SFO to regulate cardiovascular function. However, it is unknown how TNFα modulates SFO neurons to cause these effects. Therefore, we performed whole-cell patch-clamp electrophysiology and [Ca2+]i imaging on dissociated SFO neurons isolated from male Sprague-Dawley rats to determine their activity in response to TNFα. We found that acute application of TNFα depolarized 50% of SFO neurons and increased their firing rate. We also found that chronic treatment of SFO neurons with TNFα increased their excitability, an effect that was mediated, at least in part, by a hyperpolarizing shift in the activation threshold of the voltage-gated Na+ current. Furthermore, we observed that TNFα potentiated angiotensin II-induced increases in [Ca2+]i in SFO neurons. This effect was also mediated by the voltage-gated Na+ current, as tetrodotoxin prevented this potentiation. These data suggest cellular mechanisms by which TNFα increases blood pressure and sympathetic activity through actions in the SFO, and thus provide new insight into how circulating inflammatory cytokines may contribute to cardiovascular regulation in health and disease.

abstract: M.Sc.


title: Identification and characterization of transcriptional targets of TAZ in human breast cancer

contributor:
Yang, Xiaolong
Pathology and Molecular Medicine

subject:
Hippo pathway
TAZ
YAP
breast cancer
NanoString
immunology
insulin signaling

abstract: TAZ is a transcriptional co-activator and an effector of the Hippo signaling pathway. Since its discovery in 2000, we have gained tremendous insights into the roles TAZ plays in development and disease. TAZ acts as an oncogene in human breast cancers. Mechanistic studies have demonstrated that TAZ directs multiple aspects of breast cancer cell behaviour (e.g. cell proliferation, cell migration/invasion, stem cell phenotypes, chemotherapy resistance). While these processes represent critical cancer cell-intrinsic functions for TAZ, little is known about how breast cancer cell TAZ expression affects the ways that cancer cells respond to, or manipulate, factors in their tumour microenvironment (e.g. growth factors, non-neoplastic cells). Over the past decade, our lab has aimed to understand the precise gene targets transcriptionally regulated by TAZ that mediate its activities in breast cancer. In my thesis, I explore how TAZ influences breast cancer cell behaviour in response to extrinsic factors and identify specific gene targets of TAZ that mediate these interactions. First, I show that TAZ directly regulates the expression of a key component in the insulin signaling pathway, IRS1. Upregulation of IRS1 by TAZ contributes to TAZ-induced proliferation of mammary epithelial cells in 3D culture in the presence or absence of supplemental insulin. I next explore whether cancer cell TAZ expression can modify the anti-neoplastic immune response. I use NanoString to specifically screen for immune-related transcriptional targets of TAZ and discover that TAZ affects the mRNA expression of many gene targets that are relevant to immunology. I identify the immune checkpoint molecule, PD-L1 as a TAZ-regulated gene. Upregulation of PD-L1 by TAZ impairs T cell function in co-culture experiments. Interestingly, I uncover evidence that PD-L1 is not upregulated by TAZ in multiple mouse cell lines suggesting that this relationship may not be conserved across species. Through this work, I have uncovered two distinct mechanisms by which TAZ affects interactions between breast cancer cells and their environment. These findings provide insights into the roles of TAZ in neoplastic and non-neoplastic disease processes and may provide the foundation for future studies investigating novel strategies for targeting TAZ-high breast cancers.

abstract: PhD


title: Metabolic features of prostate malignancy

contributor:
Berman, David
Pathology and Molecular Medicine

subject:
prostate cancer
metabolomics
statistical modelling
desorption electrospray ionization
mass spectrometry
biomarkers
lipid metabolism
Krebs cycle

abstract:
Altered metabolism is an inherent property of cancer and provides a rich opportunity for exploring its underlying biology and developing diagnostic biomarkers. We used desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to investigate the spatial distribution of small metabolites and lipids within prostate biopsy core tissue. Thirty-five cores across 18 cases were analyzed and 965 regions of interest (ROIs) were selected corresponding to pathologically-validated benign or cancer tissue. A range of multivariate statistics were conducted to identify differentially abundant metabolites as well as for construction of a metabolic classifier of cancer tissue. Of the 25 differentially abundant metabolites, we identified increased citrate in benign tissue and increased glutamate in cancer tissue. We also identified increased levels of lyso-phosphatidylethanolamine (PE) in benign tissue and increased fatty acids (FAs) and phospholipids in cancer tissue, including; PEs, phosphatidylinositols (PIs) and phosphatidylcholines (PChs). Our data is suggestive of differential lipid metabolism in prostate cancer (PCa) needed to support development and progression of the disease. We also found that the metabolic profile of PCa was reflective of the grade of the case rather than the grade of the individual biopsy core. Differential metabolites observed between grades of PCa displayed evidence of further dysregulated lipid metabolism with increasing aggressiveness.
Additionally, we utilized a training cohort to construct a principal component analysis (PCA)/linear discriminant analysis (LDA) model which achieved an overall accuracy of 97%. Independent validation of this model on the remaining cases displayed an overall accuracy of 85%. Further studies will validate this PCa specific metabolic pathway as well as explore additional grades of PCa to identify metabolic profiles associated with each stage of aggressiveness. Ultimately, the validated accuracy of this classifier and the correlation of differentially abundant metabolites with established cancer metabolism, indicates that DESI-MSI is an effective tool for elucidating cancer metabolism with the potential for clinical translation.

abstract: M.Sc.


title: Assessing the chemical and biological recovery of Killarney Provincial Park lakes from historical acidification

contributor:
Arnott, Shelley E
Biology

subject:
Acid Rain
Zooplankton
Multiple Stressors
Sudbury
Acidification Recovery
Killarney Provincial Park
Limnology
Aquatic Ecology

abstract: Since the mid 1900s, acidification has impacted water quality and threatened the ecological integrity of thousands of lakes and streams across Eastern North America and Europe. After the implementation of industrial emission reductions programs in the late 1960s, chemical recovery of historically acid-damaged lakes was observed, but a lag in biological recovery has been partially attributed to changes in multiple environmental variables, such as warming climate, shoreline development, and the introduction and spread of invasive species. To assess the continued recovery of historically acidified lakes, forty-four lakes were sampled for zooplankton and water chemistry in and around Killarney Provincial Park during peak emissions in 1972-73, through the decades after emission reduction programs were implemented in 1990, 2000, 2005, 2011, and 2016. We assessed changes in both univariate and multivariate zooplankton community metrics through time, and evaluated recovery using a reference lake approach that included 8 circumneutral lakes within Killarney Provincial Park and 55 non- acidified lakes in Algonquin Provincial Park. In addition, we assessed the relative importance of local biotic and abiotic variables in shaping recovering zooplankton communities in Killarney and Algonquin Provincial Parks. We found strong evidence for continued chemical and biological recovery in acidified lakes in Killarney Provincial Park. Species richness and diversity increased in acid-recovered lakes to values statistically indistinguishable from those of our reference lakes, and multivariate-based community composition shifted towards a community structure more similar to reference lakes. Several variables were identified as important drivers of zooplankton community structure, including pH and ion concentrations, nutrient concentrations, fish community, water clarity, maximum lake depth, and surface area, with environmental variables accounting for less variation in communities through time. Overall, these results indicated that recovery is still progressing in historically acidified lakes, and unlike similar Canadian Shield communities that did not experience severe acidification, pH and its legacy effects are still acting as primary drivers of zooplankton community structure in Killarney Provincial Park lakes.

abstract: M.Sc.


title: Experimental and Computational Methods for Investigating Automotive Door Closure Sounds

contributor:
Mechefske, Christopher
Mechanical and Materials Engineering

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Acoustics
Acoustic Modeling
Experimental Acoustics
Computational Acoustics
MATLAB
ANSYS
Continuous Wavelet Transform
Continuous Wavelet Analysis
Octave
One-Third Octave Bandwidth
Sound Pressure
Sound Pressure Level
Rigid Body Dynamics
Explicit Dynamics
Transient Structural
Automotive
Door
Automotive Door Closure
Automotive Door Closure System
Impact
Experimental
Computational
Waveform
A-Weighting
Short Time Fourier Transform
ISO
Finite Element Method
FEM
Finite Element Analysis
FEA
Elements Per Wavelength
Microphone

abstract:
The focus of this investigation was to examine the acoustic trends present during operation of an automotive door closure at two impact speeds using experimental and computational methods. The impact speeds were 0.851m/s and 1.179m/s. Transient sound pressure measurements from five different door closure mechanisms were collected in a semi-anechoic chamber using a three-element condenser microphone array. Post-processing methodologies such as Sound Pressure Level versus 1/3 Octave Bandwidth and Continuous Wavelet Transform computations were conducted. These procedures provided an in-depth analysis on the overall generated sound in addition to identifying which frequencies dominate the response at the same time as specific impact events during latch operation. Sound quality metrics such as loudness and sharpness were used to explore how the impulsive sound relates to a consumer’s impression of the sound. It was suggested in past research that individuals prefer sounds that possess a ‘deep’ sound characteristic as opposed to sounds characterized as ‘metallic’. It was revealed that the overall sound quality was mainly influenced by the frequency composition of the sound.

The focus of this study was the sound generated by the impact events present during the latch-locking operation. With ANSYS Rigid Body Dynamics and Explicit Dynamics, it was concluded that two impact events within the latch influenced the acoustic response. The impacts occurred between the Striker/Over-Slam Bumper #1 and the Ratchet/Housing. These were labelled as the primary and secondary impact events respectively. Investigation of the experimental sound data revealed that the faster entrance speed (1.179m/s) produced a sound with a larger normalized magnitude. Furthermore, the additional energy allowed frequencies approximately 2.5kHz and below to become more pronounced. The findings suggest that increasing the closing speed could produce a “more preferred” sound based on psychoacoustic principles.

A computational acoustic analysis using ANSYS Workbench was performed to complement the experimental analysis. Only the primary impact event was simulated due to the inherent limitations of the workstation used to perform the analysis. Similarities between the computational and experimental data were present. However, it is recommended that an alternate simulation software that is capable of modelling “physical impacts” be used.

abstract: M.A.Sc.


title: Preliminary Assessment and Experimental System for Converting VOC Fumes to Hydrogen Energy

contributor:
Peppley, Brant
Chemical Engineering

subject:
VOCs
Fuel cells
Automotive Finishing
Steam reforming
Butanol steam reforming
Methanol steam reforming
Catalyst impregnation
Noble metal catalyst

abstract: The solvents used in painting and finishing are the primary source of volatile organic compounds (VOCs) in automotive manufacturing. Traditionally, VOCs have been incinerated in a Regenerative Thermal Oxidizer (RTO) that is heated using natural gas and emits significant amounts of CO_2 and H_2 O to the atmosphere [1]. The Fumes to Fuel process has been developed by Ford Motor Company to concentrate these VOCs. Optionally, hydrogen can be generated from the VOCs via steam-reforming, and purified for use in hydrogen fuel cell-powered forklifts. This process greatly reduces the amount of CO_2  emitted and generates clean energy. The overall efficiency of hydrogen production can be improved by adding a pre-reforming step before the primary steam reformer. The pre-reforming is done in the concentrator where a limited amount of VOCs are converted into hydrogen and carbon oxides. This work examined potential opportunities of the Fumes to Fuel process, including application throughout all automotive assembly plants as well as other industries to produce significant amounts of hydrogen for fuel cells. This study was followed by preliminary kinetic testing to validate an experimental setup that was built to test the catalytic performance of adsorbent supported VOC reforming catalyst. Methanol steam reforming kinetic measurements were done using a bench mark Cu/ZnO/Al2O3 catalyst at temperatures of 200, 240, and 260 ºC. Rate constants and the activation energy from these tests were compared with values from the literature and good agreement was demonstrated. The experimental setup will be used in future studies of potential adsorbent supported catalysts for pre-reforming of VOCs. These catalysts were prepared by impregnating adsorbent materials with noble metals and then characterized, though improvements should be made to the procedure, included testing different supports. These catalysts are to be tested in the experimental setup in the future now that the experimental setup is proven. The objective is to use these results to evaluate the possibility of carrying out some pre-reforming in the desorber/concentrator step of the Fumes to Fuel process leading to improved overall performance.

abstract: M.A.Sc.


title: The role of extracellular vesicles in the transfer of multidrug resistance in human ovarian cancer cells

contributor:
Cole, Susan
Pathology and Molecular Medicine

subject:
Extracellular Vesicles
Ovarian Cancer
Multidrug Resistance
p-glycoprotein

abstract:
Ovarian cancer is the fifth most common cancer in Canadian women and has the highest mortality rate of all gynecologic malignancies. First-line treatment is typically cytoreductive surgery followed by a combination of paclitaxel and carboplatin. Unfortunately, patients frequently relapse with drug resistant disease, and only 45% of patients survive beyond 5 years. Drug resistance results from multiple mechanisms, one of which is mediated by one or more of the ATP-binding cassette (ABC) drug efflux transporters. The two ABC transporters considered clinically relevant in ovarian cancer are P-glycoprotein (P-gp) and multidrug resistance protein 1 (MRP1). These plasma membrane transporters can efflux an array of solutes from the cell, including paclitaxel.
Extracellular vesicles (EVs) are a collective term for nano-sized membrane vesicles released from all mammalian cells that can serve as cell-free vehicles to deliver a variety of biomolecules to recipient cells. The human ovarian cancer cell lines A2780 and 2008, and their drug resistant variants, AD645 and 2008/MRP1, which overexpress P-gp and MRP1, respectively, were used to investigate whether transporter-containing EVs can transfer drug resistance to sensitive cells. All four cell lines were shown to release EVs isolated by differential ultracentrifugation (DUC) and size-exclusion chromatography (SEC), as indicated by the presence of EV markers CD63, CD81, and syntenin-1 in immunoblots of EV extracts. P-gp and MRP1 were also detected in EV extracts from AD645 and 2008/MRP1 cells, respectively. DUC- isolated AD645 EVs appeared toxic to A2780 recipient cells and there was no detectable transfer of paclitaxel resistance after co-culture. SEC-isolated AD645 EVs were more enriched than DUC-isolated EVs for CD63, CD81, and syntenin-1, and appeared less toxic to A2780 cells.
However, P-gp was not enriched in SEC-isolated AD645 EVs and there was no detectable ii
transfer of paclitaxel resistance or P-gp to A2780 cells. These observations suggest that the amount of functional P-gp transferred to recipient cells was insufficient to confer detectable resistance. These studies suggest that although P-gp and MRP1 can be detected in cellular material consistent with the presence of EVs, additional experiments are needed to optimize isolation of transporter-enriched EVs and co-culture conditions to detect the transfer of drug resistance.

abstract: M.Sc.


title: Neuropsychiatric-like behavioural features of the Aldh2-/- mouse model of Alzheimer’s disease

contributor:
Bennett, Brian
Neuroscience Studies

subject: Alzheimer's disease

subject: anxiety

subject: depression

subject: anhedonia

subject: Deuterium-reinforced polyunsaturated fatty acids

subject: Chronic unpredictable stress

abstract: Alzheimer’s disease (AD) is a complex, multifaceted neurodegenerative disorder characterized by progressive memory impairment and frequently presents with neuropsychiatric comorbidities, notably anxiety and depression. We have established Aldh2-/- mice as an oxidative stress-based model of age-related memory loss and cognitive impairment. However, very little is known about non-cognitive behavioural deficits, or if a sexual dimorphism exist in this model, as it does in humans. We performed a behavioural characterization of anxiety-related behaviours in response to aversive stimuli and depression-like behaviours related to despair and anhedonia. The performance of three cohorts at different time points (3-4, 7-8, and 11-12 months) was examined in a battery of behavioural tests consisting of an assessment of mobility and exploration (open field test), anxiety-related behaviour (light/dark box, elevated plus maze), and depression-related behaviour (forced swim test, tail suspension test, sucrose preference test). Compared to wild type mice, male and female Aldh2-/- mice exhibited increased anxiety-like behaviours that were first observed at 7 months of age. This anxious behaviour was prevented in Aldh2-/- mice treated with a deuterated polyunsaturated fatty acid (D-PUFA) diet for 10 weeks. Male Aldh2-/- mice exhibited a diminished preference for sucrose compared to wild type male mice. Dysfunction in the hypothalamic-pituitary (HPA) axis presents along with AD, anxiety, and depression. It was postulated that HPA dysfunction may underlie anxious and depressed behaviours in this model. This was evaluated using a mild chronic unpredictable stress (CUS) paradigm. The sucrose preference test and serum corticosterone analysis revealed no differences in response to chronic stress or acute stress between Aldh2-/- and wild type mice. These data reveal previously unreported behavioural abnormalities in the Aldh2-/- model of AD-like cognitive impairment.

abstract: M.Sc.


title: Greenhouse gas life cycle assessment of canola-derived HEFA biojet fuel in Western Canada

contributor:
Champagne, Pascale
Mabee, Warren
Civil Engineering

subject:
Canola
Rapeseed
Biojet
HEFA
Biofuel
Aviation
Life Cycle Assessment
LCA
Land Use Change
Canada
Prairies

abstract:
Biojet fuel represents the best short-term option for reducing greenhouse gas (GHG)
emissions from the aviation industry. In the near term, biojet fuel is most likely to
be produced via the hydroprocessed esters and fatty acids (HEFA) pathway. Canola
is one of the most readily available feedstocks for HEFA fuel production in Canada,
and interest has been shown in developing a domestic supply chain for biojet fuel.
However, there is substantial variation in the reported emissions reductions that
HEFA biojet from crop-based feedstocks can offer. The primary concern surrounds
the inconsistent inclusion of land use change emissions. In addition to infrequently
including land use change emissions, previous life cycle assessments (LCAs) of canola
biojet fuel have not used Canadian production data, or have failed to examine the
sensitivity of calculated emissions intensity to variation in many LCA parameters.
In this thesis, the emissions intensity of canola biojet was calculated across four co-product
allocation methods both with and without land use change emissions. Land
use change emissions from potential grassland conversion on the Canadian Prairies
were estimated using a soil carbon model. Finally, a sensitivity analysis on life cycle
inputs and co-product allocation parameters was performed.
Results suggested that without land use change, canola biojet fuel may provide
emissions reductions of 35% to 54% compared to petroleum jet fuel. Land use change
has an overwhelming influence on biojet fuel emissions intensity, and its inclusion
results in negative reductions in most cases. Emissions intensity and the sensitivity
to parameter changes varied across allocation methods. This research points to the
importance of standardized LCA methodology, and to the development of advanced
biojet fuel production pathways that do not compete for arable land.

abstract: M.A.Sc.


title: Seasonal activity, depth distribution, and microhabitat associations of resident yellow-phase American eels (Anguilla rostrata) in the upper St. Lawrence River

contributor:
Casselman, John
Cumming, Brian
Biology

subject:
American eel
Radio-acoustic telemetry
Seasonal movement
Microhabitat
Ecology

abstract: The American eel (Anguilla rostrata) is an endangered species that inhabits fresh, brackish, and oceanic waters. Eels are elusive; little is known about their seasonal movements, depth distribution, and microhabitat associations in fresh water. Radio and acoustic telemetry was used in the slow-flowing upper St. Lawrence River (1.5-by-12-km section) to study 33 transmitter-implanted large yellow-phase resident eels from September 2014 to June 2017. Semi-monthly minimum movements peaked the last part of April (450 m), first part of May (393 m), and last part of October (283 m). Eels were inactive and dormant from the last part of December to the first part of April, when they emerged and moved into shallow water (< 2.5 m) as water temperatures approached 10 ºC. Eels moved slightly deeper in summer as temperatures peaked, likely following prey-fish movements, started moving deeper in October as temperatures dropped below 8 ºC, and settled for the winter in December at approximately 3.8 m. Telemetry allowed precise locating of eels (approximately 1,500), enabling detailed examination of microhabitat associations. Substrate properties, vegetative biomass, and cover were analyzed throughout the study area to describe habitat that was available (34 sites), selected (31), and never frequented (non-selected, 6). Two general ecotypes were found: one that associated with soft substrate with vegetative cover, mainly the green algae Chara vulgaris, and the other with hard substrate and large rock cover. The soft substrate ecotype dominated (88%); sediment was significantly softer, quantified by an impact penetrometer, and higher in organic content (> 14 %) compared with available and non-selected habitats. Site fidelity among seasons and years was remarkable: four eels consistently used the same rock cover from spring to fall, but all eels overwintered in soft substrate at sites that were slightly harder and had significantly lower organic content (P = 0.026) and Chara biomass (P = 0.007) than summer and fall sites. Discriminant analyses determined that most of the variance in distribution of eels is related to substrate type, followed by vegetative cover, primarily Chara. Telemetry revealed that eels had consistent and very predictable seasonal activity patterns and specific microhabitat associations and preferences.

abstract: M.Sc.


title: Inclusion of Indigenous Education: Examining Pre-service Teachers' Knowledge and Attitudes Towards the Integration of Indigenous Education

contributor:
Morcom, Lindsay
Education

subject:
Indigenous Education
Pre-service Teachers
Teacher Development

abstract: Teacher apprehension towards integrating Indigenous perspectives into the general classroom curriculum is an issue that should become a priority in Ontario Faculties of Education. Teachers’ attitudes and perceptions towards Indigenous education can impact instructional judgments and pedagogical decisions, which influence the learning opportunities afforded to Indigenous and non-Indigenous students (Riley & Ungerleider, 2012; Pajares, 1992; Cantu, 2001). The Truth and Reconciliation Commission’s (TRC) Calls to Action Report outlines the necessity to improve the quality of teacher knowledge, understanding, delivery and integration of Indigenous content (2015). The purpose of this study is to explore pre-service teachers’ knowledge of Indigenous education and their attitudes towards including Indigenous perspectives in the general classroom, prior to and after completing a mandatory introduction to Aboriginal studies course. The purpose was informed by two research questions: 1) What baseline knowledge and attitudes toward Indigenous curriculum integration are pre-service teachers entering and leaving the Faculty of Education with? 2) Does coursework adequately prepare pre-service teachers to confidently integrate Indigenous content into the general classroom? A mixed-method study was conducted using a sequential explanatory design, examining 117 pre-service teachers from Queen’s University, Canada. Pre-course and post-course data was collected through surveys and in-depth individual interviews. Survey data analysis indicated differences from pre-course (time 1) to post-course (time 2). Additionally, eighteen individual interviews were conducted. Overall, pre-service teachers had positive attitudes towards integrating Indigenous perspectives into the general classroom but lacked content knowledge and believed that their weakness in preparation to integrate Indigenous Education into the general classroom was due to their teacher education program design. Findings of this study will be of interest to Faculties of Education, policy makers and teacher educators.

abstract: M.Ed.


title: A Defence of Associative Duties

contributor:
Sypnowich, Christine
Philosophy

subject:
Associative Duties
Special Responsibilities
Ethics
Liberalism
Value Theory
Samuel Scheffler
Compatriot Partiality
Nationalism
Cosmopolitanism

abstract: In this thesis, I defend associative duties – typically understood as non-contractual, special moral responsibilities that arise from valued relationships – as a genuine class of duties. I do this in the spaces of both normative ethics and liberal, political philosophy. The thesis accordingly has two parts. In the first, I defend a particular account of associative duties against their reduction to obligations and conventional divisions of moral labour, and against popular rival accounts that view associative duties not as duties so much as instruments for realizing a valuable state of affairs in which the relationships to which they are socially attached exist. I suggest the following instead: certain relationships are characterized by properties that constitute moral reasons – which in cases amount to duties given their symmetricity and weight – whose recognition is the same as non-instrumentally valuing the relationships. In the second, I defend the claim that we owe associative duties to our compatriots while in dialogue with liberalism, whose twin values of liberty and equality both cut against associative duties qua non- contractual responsibilities to afford priority to the welfare of our associates. By outlining problems that arise from her traditional eschewing of associative duties, I tempt the liberal to an interpretation of the conflicts between her values and associative duties as “extrinsic”, that is, as between genuinely competing values and their attendant demands.

abstract: M.A.


title: High Fidelity Additive Manufacturing Process Modeling for Residual Stress and Deformation

contributor:
Kim, Il Yong
Mechanical and Materials Engineering

subject:
Additive Manufacturing
Residual Stress
Parameter Analysis
Mesoscale Modeling
Finite Element Analysis
ANSYS
Element Birth and Death
Gaussian Laser Distribution
Powder Bed Laser Scanning

abstract:
The ever increasing demand for high speed transport is causing a massive increase in the amount of passengers utilizing air travel. To be able to meet the ever increasing regulatory demands for reduced emissions that are being placed on the air travel industry, there exists an ever present need to advance their technology at an incredible pace. This leads to development and use of the most cutting edge and advanced technologies available, such as Topology Optimization and Additive Manufacturing. Challenges still remain in being able to effectively utilize these technologies as they are both relatively new, however integrating the two together has massive potential for the air travel industry to meet and exceed the emissions regulations.
This work presents the methodology for developing a high fidelity mesoscale simulation of the additive manufacturing process which considers all aspects of the machines and the process parameters involved with the construction of components, including the effects of powder bed, Gaussian laser distributions, and specific laser movements. The methodology utilizes the element birth and death finite element formulation to simulate the addition of layers over time and also performs a full transient thermo-mechanical simulation to capture both the temperature history related to the moving heat source, as well as the effect of the temperature history on the residual stress and deformation that is inherent in components generated through additive manufacturing. The methodology was validated by comparing in-situ temperature measurements to the simulation data and was deemed acceptable by achieving 15% error throughout the process. The final stage of this work involved a parameter analysis to capture the effects of the parameters on the residual stress and deformation. Results showed agreement with other literature results, and provided trends that shed some light on the uncertainty of the AM process in hopes of providing recommendations for the development of a methodology for large scale process modeling.

abstract: M.A.Sc.


title: Alteration in MicroRNA Expression Pattern in CD-1 Mouse Fetal Liver Cells Following In Vitro Benzoquinone Exposure

contributor:
Winn, Louise
Biomedical and Molecular Sciences

subject: Benzene, Fetal liver, microRNA

abstract: The incidence of childhood leukemias in developed countries is increasing and in utero exposure to environmental toxicants such as benzene may be primarily responsible. The mechanism behind benzene- induced hematotoxicity is not completely understood, however, previous work from our laboratory has demonstrated that following in utero exposure to benzene, CD-1 mice one year after birth had an increased incidence of hematopoietic tumours. This suggests that molecular changes before birth could be responsible for the development of childhood leukemias. The objective of this thesis was to investigate whether altered MicroRNA (miR) expression following exposure to benzoquinone (BQ) in fetal hematopoietic cells is a potential pathway by which environmental toxicants could initiate in utero carcinogenesis. To test this, fetal liver cells isolated from gestational day (GD) 14 CD-1 fetal mice were exposed to BQ in vitro for 3 hours. The identification of largescale expression pattern changes in miR expression pattern in a subset of miRs was then conducted using a hybridization array plate. The finding that BQ was able to alter miRs in fetal liver cells led us to examine specific miRs identified in the literature to be associated with hematotoxicity, including miR-146a, miR-155, and miR-19b. Evaluation of miRs through qRT-PCR identified significant increases in miR-155 and miR-19b in fetal hematopoietic cells following 6 hours of BQ exposure, however no difference was observed in miR-146a expression at any time point. To investigate if the miR expression change had decreased downstream mRNA targets, we evaluated targets of miR-155 (c-Myb and Sfpi1) and miR-19b (Pten). There was no statistically significant differences in any of the mRNA evaluated, however there was a trend towards decreased levels of c-Myb and Sfpi1 mRNA expression following BQ exposure for 6 hours, correlating with the time of increased miR-155 expression. This study reveals miRs as a potential mechanism of benzene-induced hematotoxicity, and highlights the importance of continuing to understand the mechanisms for in utero benzene-initiated hematotoxicity for potential therapeutic targets.

abstract: M.Sc.


title: Instructing Nursing Students on Early Identification and Screening for Postpartum Depression Using Simulation Training

contributor:
Edge, Dana
Nursing

subject:
Simulation
Postpartum depression
Maternal nursing care

abstract:
Early identification of depressive symptoms associated with postpartum depression (PPD) is key to its treatment.  Nurses’ lack of skills and knowledge were identified in the literature as barriers to screening for postpartum depression.  In this study the researcher explored the use of simulation to instruct undergraduate nursing students on the screening and care for PPD.
A quasi-experimental design study was conducted in the Fall 2017 and Winter 2018, with a convenience sample of senior undergraduate nursing student at Queen’s University (n=19).  Knowledge, attitudes, perceived communication skills and confidence were measured pre- and post-simulation training using a 26-items and 12 statements Perinatal Depression Monitor tool.  A strong knowledge base and positive attitudes toward PPD were found prior to and after simulation.   Nearly 78% of participants strongly agreed with the statement that “Nurses should assess early and often for PPD”.  The participants’ mean scores of perceived communication skills and confidence levels increased in the posttest (communication skills, pretest M: 3.68, posttest M: 4.15; confidence, pretest M: 2.73, posttest M: 3.57).
As the simulation in this study was the first experience for most of the participants to practise a scenario involving PPD, it was found that this simulation aligns with the Knows How level in Miller’s (1990) Pyramid of Clinical Competence.  The lack of knowledge regarding the use of the Edinburg Postnatal Depression Scale screening tool and community PPD referral resources for mothers at risk for PPD were evident among the study participants.  This discrepancy suggests a gap between the Shows How and Knows How levels in the pyramid.  It is recommended that undergraduate students be taught with scenarios involving screening for PPD in their nursing curriculum (3rd year) to better prepare them to reach the Shows How level in the simulation laboratory.  This will ideally increase the students’ competence and preparedness to screen for PPD and provide nursing care for patients with PPD in their practice.

abstract: MNSc.


title: Robotic Needle-based Intra-cavitary Surgery (InCavBot)

contributor:
Ciccarelli, Gabriel
Mechanical and Materials Engineering

subject: medical robotics

subject: robotic needle insertion

subject: robotic brachytherapy

subject: needle driving

subject: needle oscillation

subject: intra-cavitary robotic system

subject: phantom-based needle insertion platform

subject: intra-cavitary needle guide

subject: mutli-needle insertion

abstract: Intra-cavitary needle-based interventions are challenging due to highly deformable cavity and targeted tissue motions. Multi-needle insertions are more challenging given the continuously shifting boundary conditions of surrounding structures intra-operatively. This thesis presents the furtherment of enabling technologies for surgeries seeking to enhance treatment effectiveness by improving needle insertion performance. A modular phantom-based insertion platform was designed and implemented as a framework for comparative studies. The main elements of this platform -- organ phantom, needle guidance unit, and needle driving unit -- were defined for intra-cavitary brachytherapy in cancer treatment with potential for other investigations. The platform performance was conducted through force/torque and electromagnetic data acquisitions. A novel needle driver was devised combining simultaneous translational and rotational oscillations at needle base to investigate optimum needle motion within intra-cavitary limitations having the minimized needle-tissue interaction while maintaining needle mechanical properties for non-straight needle guides. Optimal hybrid oscillational needle motion through in-vitro experiments were concluded to achieve a desirable velocity-independent force profile. A force model encompassing combined oscillations was developed to estimate axial needle force. A multi-stage insertion methodology was elaborated to characterize the interaction between needle and guide within needle-tissue interaction. The intra-operative frictional controllability (IFC) index is proposed for insertion performance management using the frictional power rate of the needle through its guide at different insertion velocities, since velocity changes are inevitable. IFC provides effective criterion to surgeons for optimal needle management specifying power change requirements during velocity-sensitive needle guide frictional reactions. Minimizing the range of frictional power changes, intra-operatively, increases control over the insertion process. IFC was calculated for two needle guides using the implemented platform. A multi-needle-insertion-based intra-cavitary robotic system (InCavBot) resulted from preliminary evaluation and design factors accounting for all requirements and constraints. Kinematic and workspace analyses were conducted for the candidate system that incorporates two serial manipulators. A volumetric index was introduced to prioritize the needle insertion order, based on changes in the targeting workspace after each insertion. Design concepts and prototypes were presented for a proactive intra-cavitary needle guide with organ immobilizing options, a hybrid oscillational needle driving hand tool, and an intra-cavitary needle anchorage unit.

abstract: PhD


title: A novel actuator for high-torque low-speed applications

contributor:
Hashtrudi-Zaad, Keyvan
Bakhshai, Alireza
Liu, Yan-Fei
Electrical and Computer Engineering

subject: Motors, control, Bidirectional motion, Drive, Microcontroller

abstract: Restricted

abstract: M.A.Sc.


title: The Ultimate Performance Enhancement? A History of Ideas About Sleep as a Training Tool in High Performance Sport

contributor:
Adams, Mary Louise
Kinesiology and Health Studies

subject:
Sleep
Sport
Sleep Science
Fatigue
Rest

abstract:
The recent emergence of “sleep positivity” in high performance sport, as characterized by the expansion of scientific sleep research and expertise, the growing availability of commercial sleep products, and new sleep technology companies, increasingly shapes how sleep-related problems are defined and managed in the athletic realm. Scientific evidence and common sense consistently link lengthy and sufficient sleep in athletes to enhanced performance and wellbeing. However, such optimistic views of sleep stand in contrast to the conditions of high performance, which regularly expose athletes to experiences of fatigue, overtraining, and sleep loss. I address this contradiction by offering a feminist critical history that aims to makes sense of the beliefs, values, and assumptions that position optimal personal sleep habits as “the” solution to a range of problems that arise within exhausting competitive sport systems. What if more sleep isn't really what athletes “need”?

Influenced by Michel Foucault’s “history of the present” and the feminist cultural studies of sport literature, I develop a methodological framework that allows me to trace how understandings of sleep in sport have shifted across the twentieth and early twenty-first century. By drawing on a range of historical materials, including archival documents, athletic training manuals, coaching guidebooks, newspapers, textbooks, peer-reviewed journals, films, commercial advertisements, and the online materials of sleep-optimizing companies, I show that while sleep may be a biological necessity, it is also a cultural phenomenon. I explore how ideas and discourses related to sleep serve as a site of governance and examine the way that understandings of “good” sleep have often led to the moral and physical regulation of athletes. I argue that instead of assuming that the promotion of sleep in athletes’ lives is unambiguous and benevolent, it is important to examine the cultural and historical conditions that shape such prescriptions in the first place. I challenge sport scholars and sport practitioners to seriously consider the limitations of “healthy” high performance sport and bring attention to the way that the realm of competitive sport shapes broader understandings of sleep-related problems and the types of solutions that might be offered in response to them.

abstract: PhD


title: Distance to specialist medical care and diagnosis of obstructive sleep apnea in rural Saskatchewan

contributor:
Pickett, William
McIsaac, Michael
Public Health Sciences

subject: rural; distance; specialist care; diagnosis; obstructive sleep apnea

abstract:
Background: Obstructive sleep apnea (OSA) is the most common sleep-disordered breathing condition. Rural populations in Canada may be particularly at risk due to high reported levels of obesity, physical inactivity and other related risk factors. Patients with OSA symptoms are often not diagnosed clinically, which is a concern given the health and safety risks associated with unmanaged OSA. The availability of fewer practicing medical specialists combined with longer travel distances to access healthcare services results in barriers to diagnosis and treatment in rural communities.

Objectives: This study aimed to (1) determine whether the proportion of adults reporting OSA symptoms and no sleep apnea diagnosis in rural populations varied by travel distance to specialist medical care; and (2) assess whether any distance-related patterns were attributable to differences in the frequency of sleep apnea diagnosis among adults who may require sleep specialist care.

Methods: We used a cross-sectional epidemiologic study design, with longitudinal confirmation of key findings. Our study base included adults who completed a 2010 baseline questionnaire for the Saskatchewan Rural Health Study; the follow-up phase of the study began in 2014 and ended in 2015. 6525 adults from 3731 households made up our sample. Statistical analyses used log-binomial regression.

Results: Rural adults who reported the largest travel distances (≥ 250 km) to specialist medical care were 1.17 (95% CI: 1.07, 1.29) times more likely to report OSA symptoms and no sleep apnea diagnosis compared to those who reported the smallest (< 100 km) distances. However, the proportion of sleep apnea diagnoses was low and unaffected by reported travel distance among adults who may require sleep specialist care.

Conclusions: In rural Saskatchewan, there was a greater OSA burden among adults reporting the largest travel distances to access specialist medical care, which suggests decreased use of healthcare services in remote populations. However, among adults who may require sleep specialist care, the proportion of sleep apnea diagnoses was low and unaffected by reported travel distance. Other healthcare access barriers may be contributing to the low sleep apnea diagnostic rate and should be evaluated in future research.

abstract: M.Sc.


title: “A (Re)turn to the Archive:  Reading the Lives and Works of Yvonne Vera and Dambudzo Marechera”

contributor:
Jolly, Rosemary
Bongie, Chris
English Language and Literature

subject:
Literature
Archives
Zimbabwe
Life Writing
Neoliberalism

abstract: In this dissertation, I read the life and work of the Zimbabwean authors, Yvonne Vera (1964 – 2005) and Dambudzo Marechera (1952 – 1987), against a set of assumptions about the work of African life storytelling in late liberalism. The circulation and reception of narrated lives in the global literary marketplace tends to centre a form of liberal subjectivity premised on the presumed virtues of speech and presence, supporting a series of claims about the therapeutic value of representation in the event of Africa’s historical traumas. I argue that the trauma-informed narratives that Vera and Marechera present in their fiction put pressure on conventional notions of trauma that emplot therapeutic understandings of postcolonial narrative in which the telling of one’s story brings release from that story. Both Vera and Marechera resist the normative development of personhood that presumes self-disclosing speech acts to be universally therapeutic, and that underwrites developmentalist notions of improvement and inclusion. To demonstrate this, I read a form of silence in Vera’s archive and in her fiction that resists western oppositional hierarchies between silence and speech, and a parallel form of refusal, in Marechera’s archive, to perform his ‘arrival’ on the world literary stage as a redemptive ending to the harrowing story of his birth in the Harare townships. I trace their attempts to make suffering matter differently, against a backdrop of nationalist suffering writ large in the master fiction of collective struggle in Zimbabwe, and against a conventional view of African suffering that appeals abstractly to a global literary audience as a form of normative emancipation from the postcolonial condition, arguing that both authors imagined forms of freedom beyond their conscription into the world of Man.

abstract: PhD


title: Mathematical Modeling of Arborescent Polyisobutylene Production in Continuous and Semi-Batch Reactors

contributor:
McAuley, Kim
Zhao, Yutian
Chemical Engineering

subject:
continuous stirred-tank reactor
method of moments
polyisobutylene
self-condensing vinyl polymerization
parameter estimation
carbocationic polymerization
hyperbranched polymer

abstract:
Mathematical models are developed for arborescent polyisobutylene (arbPIB) production in continuous-stirred-tank and semi-batch reactors. The objective of the research is to assess how reactor type influences final polymer properties and to use the new semi-batch model for parameter estimation with existing literature data. A multidimensional method-of-moments technique is used to predict number and weight-average molecular weights and branching levels.
	The continuous stirred-tank reactor (CSTR) model developed is used to simulate arbPIB polymerization over a range of different residence times and inimer feed concentrations. It is shown that polydispersity and average branching level are higher for polymer produced in a CSTR compared to polymer produced in batch. It is also shown that operating a CSTR at long residence times and/or high inimer feed concentrations will result in an inability to reach steady-state operation due to the weight-average molecular weight increasing indefinitely. This range of instability for CSTR operation is larger for SCVCP than for inimer homopolymerization because of the relatively high apparent rate constant associated with the isobutylene comonomer reacting with an inimer branching agent.
	In addition, a semi-batch model is developed that incorporates a material balance on Lewis-acid concentration. Lumped parameters (containing true rate constants and equilibrium constants) are estimated using literature batch and semi-batch data for arbPIB. Two attempts are made to fit these data by applying different mechanistic assumptions. Unfortunately, parameters estimated from these studies are unable to provide simulation results that accurately fit the experimental data. It is recommended that additional experimental data be collected at various reaction conditions, including replicate semi-batch data, before improved modeling assumptions are developed.

abstract: M.A.Sc.


title: Characterizing the effects of in utero exposure to valproic acid on murine fetal heart development

subject:
valproic acid
congenital heart defects
cardiac contractility
high resolution ultrasound imaging

abstract: Many antiepileptic drugs on the market, including valproic acid (VPA), have a wide range of therapeutic effects in addition to treating epilepsy. In recent years, the use of VPA in the treatment of psychiatric conditions has been on the rise. However, studies have shown that in utero exposure to VPA can have detrimental effects on embryonic development. Specifically, in utero exposure to VPA has been associated with a higher risk of congenital heart defects. In spite of this, expectant mothers are advised to continue taking it throughout pregnancy to prevent seizures. One proposed mechanism of VPA-initiated teratogenicity is the inhibition of histone deacetylase (HDAC), which is involved in the regulation of transcription factors associated with cardiogenesis. Myocyte enhancing factor 2C (Mef2c), a transcription factor involved in development of cardiac structure and cardiomyocyte differentiation, has been shown to increase in response to in utero VPA exposure. Furthermore, this increase in gene expression has been associated with contractile dysfunction and myocardial disorganization. To characterize the effects of VPA on murine heart development, pregnant CD-1 mice were dosed with 400 mg/kg of VPA on gestational day (GD) 9 and ultrasounds were performed on GD 14 to 18, prior to harvesting the fetal hearts on GD 19. Using high-resolution ultrasound (HRUS) technology, we examined the effects of VPA on cardiac contractile function, followed by histology to evaluate the effects of VPA on myocardial organization and ventricular lumen diameter.  Lastly, we conducted qRT-PCR to measure the relative Mef2c gene expression in GD 16 murine hearts. Qualitative analysis of the murine hearts at GD 19 showed structural anomalies only in the hearts of VPA-treated mice. Additionally, our results showed a decrease in contractile ability of VPA-treated mice compared to the control group on GD 18 and an increase in both anterior and posterior myocardial wall contraction on GD 14 and GD 15. We did not find any effects of VPA on the gene expression of Mef2c. Together these results further characterize the effects of VPA on heart development and suggest that increased Mef2c gene expression, at least on GD 16, does not mediate VPA-induced cardiotoxicity.

abstract: M.Sc.


title: Placental Growth Factor Modulates Vascularization and Neuroanatomy in Mice

contributor:
Tayade, Chandrakant
Croy, B. Anne
Anatomy and Cell Biology

subject: Preeclampsia

subject: Development

subject: Developmental Origins of Health and Disease

subject: Brain

subject: Retina

subject: Behaviour

abstract: Preeclampsia (PE) is a common pregnancy complication and may result in fetal stress with lifelong consequences for cognition. Offspring cognitive alterations are associated with distorted neuroanatomy and cerebrovasculature. Although the pathophysiology is complex, reduced expression of pro-angiogenic factors may result in impaired fetal vascularization, altered brain structure and impaired cognition. In particular, low concentrations of placental growth factor (PGF) may alter neural development. Pgf -/- mice were used to interrogate the role of PGF in central nervous system vascularization, appropriate neuroanatomy and behaviour. Subsequently, Pgf -/- mice were used to investigate the postnatal period as a window for intervention. Pgf -/- mice were hypothesized to have impaired cerebrovascular development with permanent deviations of the cerebrovasculature, neuroanatomy and behaviour. Adult deficits were hypothesized to be correctable with an early postnatal PGF treatment. Whole-mount immunofluorescence of the brain and retina examined vascularization and circle of Willis connectivity. Micro-CT imaging visualized the entire cerebrovasculature in adult mice. Magnetic resonance imaging determined the volume of 62 unique structures in the adult mouse brain. Behavioural testing of adult mice examined spatial learning, object recognition, depressive-like behaviour and anxiety-like behaviour. As a postnatal treatment, recombinant PGF was administered to Pgf -/- mice from postnatal day 1-10 before examination of the cerebrovasculature, neuroanatomy and behaviour in adulthood. Pgf -/- mice exhibited delayed vascularization of the hindbrain, less connectivity of the circle of Willis and altered arteriovenous organization in the retina. In adulthood, more small-diameter cerebral vessels were present and 10/62 structures in the brain had smaller volume. On behavioural testing, Pgf -/- mice exhibited poorer performance on spatial learning tests but better performance on depressive-like behaviour and object recognition tests relative to Pgf +/+ controls. Postnatal PGF treatment altered adult neuroanatomy and behaviour but not the cerebrovasculature. In particular, treatment with 70 pg/g PGF partially corrected alterations seen in Pgf -/- mice. Overall, PGF is important for cerebrovascular development, adult neuroanatomy and cognitive behaviour in mice. PGF deficiency may be one factor in a PE-gestation that leads to altered offspring brain development. Finally, the postnatal period is a potential time for intervention in offspring after PE-impacted gestation.

abstract: PhD


title: Auditors' Career Transitions: Three Studies on Auditors' Recruitment into Public Accounting, Transition to Industry, and the Long-lasting Effects of their Auditing Experience

contributor:
Malsch, Bertrand
Business

subject:
Auditor-client relationships
Big Four accounting firms
Career transitions
Ex-auditors
Memory work
Professional identity
Public accounting recruitment

abstract:
In my thesis, I investigate the career transitions of auditors. In the first study, I explore students’ experience going through the recruitment process in public accounting. I conducted 51 interviews with undergraduate students and I performed observations of 14 recruitment events in Canada, in the provinces of Quebec and Ontario. At the theoretical level, my analysis builds on Bourdieu’s scholarship. I find that students’ construct the desire to work for Big Four firms, and learn to develop the proper habitus—a way of conducting oneself—and to convert their cultural capital into social capital—a network of relationships. However, several students expressed a sense of dissonance following the process because their expectations about the nature of the job and the lifestyle were not met.

My second and third studies are based on 37 semi-structured interviews conducted with ex-auditors in Canada. In the second study, I investigate auditors’ exit from accounting firms and their identity reconstruction in a new position. My empirical analysis was guided by key insights from the literature on memory and auditors’ social identity. I find that ex-auditors, while remembering the wrong of the past, primarily about their treatment by the firms, also attempt to restore their professional self after leaving accounting firms. They reinvent a positive identity and a glorious period during which they forged invaluable connections, earned high recognition for their expertise, and became part of a professional elite.

In the third study, I investigate former auditors’ enactment of their role of auditees. I use theories of expert knowledge and social capital. I find that auditees with a working experience in auditing influence auditors’ work by using three different strategies: 1) Setting the ground by filtering in advance the production of auditing information while bonding socially and emotionally with the audit team; 2) Training staff auditors by teaching them technical knowledge and developing coaching-style relationships; and 3) Regulating staff auditors’ professional judgments by questioning their opinions and monitoring their conduct.

Overall, my dissertation contributes to our understanding of three major themes in the accounting literature: auditors’ identity, auditors’ social capital and the commercialization of the profession.

abstract: PhD


title: Experimental Modal Analysis of a Half-Scale Model Rear Twin-Engine Mounted Aircraft Fuselage Section

contributor:
Mechefske, Christopher
Mechanical and Materials Engineering

subject:
Modal Analysis
Aircraft
Noise
Vibration

abstract: Experimental modal testing using an impact hammer is a commonly used method for obtaining the modal parameters of any structure for which the vibrational behavior is of interest. Natural frequencies and associated mode shapes of the structure can be extracted directly from measured FRFs (Frequency Response Functions) through various curve fitting procedures. This thesis provides an overview of the modal testing conducted on various scaled aerospace components. These components are part of a half-scale model rear twin-engine mounted aircraft fuselage tail section which is being constructed in order to provide relevant vibrational and dynamic trends to a leading Canadian aerospace manufacturer. The experimental modal results were used to validate the associated computational modal data. It is this initial validation step which forms the foundation of the research project presented herein and which will allow for future modal testing work to be conducted on the half-scale assembly once completed. Testing set-up, experimental equipment and the methodology employed are all described in detail.  Furthermore, a series of validity checks were done by ensuring that the experimental results satisfy the requirements inherent to linear modal analysis including repeatability, reciprocity and linearity. This provided confidence in the employed testing procedure. Recorded natural frequencies (eigenvalues), mode shapes (eigenvectors), coherence plots and other important experimental data are presented along with notable trends. Finally, key literature has been referenced where appropriate and important concepts to modal analysis are expanded upon. This thesis, then, demonstrates that experimental modal analysis can be successfully implemented into a testing methodology that helps establish vibrational trends and, thus, better understand and help resolve vibro-acoustic issues on aircraft.

abstract: M.A.Sc.


title: The role of HSV-2 UL16 in nuclear egress of capsids

contributor:
Banfield, Bruce
Biomedical and Molecular Sciences

subject:
UL16
nuclear egress
HSV-2
capsids
secondary envelopment
critical

abstract:
The herpes simplex virus (HSV) UL16 gene is conserved throughout the Herpesviridae and the herpes simplex virus type 1 (HSV-1) UL16 protein forms complex with another virus protein called UL21. Previous studies demonstrated that, unlike HSV-1, herpes simplex virus type 2 (HSV-2) UL21 was essential for virus propagation and the translocation of capsids from the nucleus to the cytoplasm - a critical process in virus morphogenesis called nuclear egress. We hypothesized that if a UL16/UL21 complex were required for nuclear egress then HSV-2 lacking UL16 would have a similar phenotype as HSV-2 lacking UL21. Deletion of HSV-2 UL16 resulted in a 200 to 4,000-fold reduction in virus propagation, depending on the cell type, and like UL21, UL16 was critical for the nuclear egress of capsids.
 Our findings related to HSV-2 UL16 were in stark contrast to what has been observed with UL16 mutants of HSV-1 and pseudorabies virus (PRV) where roughly 10-fold replication deficiencies were reported that were accompanied by defects in the secondary envelopment of cytoplasmic capsids. To resolve these discrepancies, multiple UL16 null mutants were constructed in different HSV strains and their phenotypes characterized side-by-side. This analysis showed that all the HSV-2 UL16 mutants had 50 to 100-fold replication deficiencies that were accompanied by defects in the nuclear egress of capsids as well as defects in the envelopment of cytoplasmic capsids. By contrast, most HSV-1 UL16 mutants had 10-fold replication deficiencies that were accompanied by defects in envelopment of cytoplasmic capsids. These findings indicated that UL16 has HSV species-specific functions.
Nuclear egress requires the disruption of the nuclear lamina and proper localization of nuclear egress complex (NEC) components, UL31 and UL34. To investigate the requirements for UL16 and UL21 in nuclear egress we examined the disruption of the nuclear lamina and the localization of NEC in infected cells. Similar to UL21, UL16 was not involved in the disruption of nuclear lamina integrity. Interestingly, HSV-2 UL21 is required for proper localization of the NEC while UL16 is not, suggesting that UL16 and UL21 play distinct roles in the nuclear egress of HSV-2 capsids.

abstract: PhD


title: Tuning Spark Performance

contributor:
Martin, Patrick
Computing

subject: Apache spark

abstract: In the big data era, big data frameworks play a vital role in storing and processing large amounts of data, providing significant improvements in performance and availability. Spark is one of the most popular big data frameworks, providing high scalability and fault-tolerance with its unique in-memory engine. To hide the complex settings from users, Spark has approximately 200 configurable parameters in the execution engine. Default values assigned to the parameters provide initial ease of use. However, the default values are not the best setting for all workloads. In this work, we propose a general tuning algorithm named QST, Queen’s Spark Tuning, to help users with tuning Spark and to improve overall performance. First of all, we study Spark performance for a variety of workloads and identify 9 tunable parameters among more than 200 parameters that have significant impact on performance. Then, we propose QST, a general greedy iterative tuning algorithm for our set of 9 key parameters. By classifying Spark workloads as memory-intensive, shuffle-intensive or all-intensive, QST configures the parameters for each type of workload. We perform an experimental evaluation of QST using benchmark workloads and industry workloads. In our experiments, using QST significantly improves Spark performance. Overall, using QST yields an average speedup of 65% for our benchmark evaluation workloads and 57% for our industry evaluation workloads.

abstract: M.Sc.


title: Susceptibility of the hERG Potassium Channel to Proteases and its Clinical Implications

contributor:
Zhang, Shetuan
Biomedical and Molecular Sciences

subject:
hERG
Long QT syndrome
Ischemia

abstract:
Cardiovascular diseases are the leading cause of death worldwide. Cardiac ischemia  accounts for approximately 50% of all cardiovascular-related deaths. Cardiac ischemia is associated with high incidence of QT prolongation and cardiac arrhythmias. Hypoxia is a common pathophysiological factor experienced during cardiac ischemia. Inflammation and leukocyte infiltration is also enhanced during ischemic insults. Additionally, the activation, upregulation and secretion of several different proteases occur during cardiac ischemia. The mechanisms surrounding ischemia-induced QT prolongation and cardiac arrhythmias are not fully understood. The aim of this thesis was to gain a better understanding of the underlying mechanisms of ischemia-induced cardiac arrhythmias and sudden death.
Dysfunction of cardiac ion channels is directly responsible for the generation of cardiac arrhythmias. In particular, loss of function of the potassium channel, hERG, leads to QT interval prolongation and cardiac arrhythmias. The hERG potassium channel has also been suggested to be uniquely susceptible to extracellular proteases. Thus, we hypothesized that hERG dysfunction due to protease cleavage of the channel during cardiac ischemia plays a role in ischemia-induced QT prolongation and cardiac arrhythmias. We observed that proteases selectively cleaved hERG/IKr extracellularly in the S5-pore linker of the channel. We demonstrated that glycosylation which occurs in the S5-pore linker of hERG, as well as the BeKm-1 scorpion toxin, which binds to the S5-pore linker of hERG, protects the channel from protease cleavage. To determine whether proteases upregulated, activated and secreted during cardiac ischemia affect hERG, coronary ligation of the circumflex artery was performed on a rabbit model. Among the proteases shown to be upregulated during ischemia, calpain-1, which was secreted to the extracellular milieu, cleaved hERG in the S5-pore linker. Consistent with a decrease in hERG function in ischemic conditions, a calpain-mediated reduction of hERG was also observed in hypoxic conditions. The effect was abrogated with the treatment of BeKm-1 and calpain inhibitors.
In summary, proteases upregulated and secreted, cleave hERG during ischemic and hypoxic insults, which can be prevented with protease inhibitors and hERG targeting peptides. The present work extends our understanding of the mechanisms that underlie cardiovascular disease-related mortality while revealing potential preventative treatment options to combat ischemia-induced arrhythmogenesis.

abstract: PhD


title: Neuropeptides in the Bed Nucleus Stria Terminalis: Implications in Chronic Stress

contributor:
Dumont, Eric
Neuroscience Studies

subject:
Neurotensin
Corticotropin releasing factor
Dynorphin
Chronic Stress
Anxiety
Synaptic plasticity

abstract: For the last 20-30 years, new discovery of pharmacological treatment for psychiatric disorders has been stagnant despite a pressing need to find alternative therapies for patients that are treatment-resistant to the current medication. Neuropeptides are powerful modulators of neural activity that robustly influence a wide-range of behaviours. Notably, their expression profiles and subsequent function can be altered in some mental health illnesses such as anxiety disorders. However, neuropeptides are rarely studied in clinically relevant contexts. Consequently, there is currently a lack of understanding of how they may predict or contribute to certain pathological states. Pre-clinical models in rodents are useful tools to investigate this. The chronic unpredictable stress (CUS) is one model that mimics the every day stressors that can lead to pathologies in humans. Here, we hypothesize that neuropeptide modulation will be altered after male rats are exposed to CUS resulting in changes in behaviour. Specifically, we look at the effect of neuropeptides in the oval bed nucleus of the stria terminalis (ovBNST), a brain area sensitive to energy homeostasis and the anticipation of aversive stressors. We found that endogenously released neuropeptides robustly modulate both excitatory and inhibitory transmission. Interestingly, CUS altered neuropeptides regulation of synaptic transmission whereby one neuropeptide (neurotensin (NT)) became the dominant modulator of inhibitory transmission. To investigate whether this had behavioural consequences, we pharmacologically blocked NT in the ovBNST and tested rats in the elevated plus maze (EPM) and forced swim test (FST). We observed changes only in exploratory behaviour in the CUS rats where blockage of NT increased time spent in the open arm suggesting a reduction in anxiety-like behaviour. Lastly, knowing that modulation of inhibitory transmission is specifically changed with CUS, we examined how neuropeptides may influence the main inhibitory inputs to the ovBNST: the central amygdala (CeA). We found that NT and dynorphin antagonistically modulate CeA-to-ovBNST inputs. Whether this modulation changes in different conditions or animal state remains elusive. Overall, multiple neuropeptides regulate the activity of ovBNST neurons that is dysregulated following a chronically stressful experience (i.e., CUS) but whether these changes observed are adaptive or maladaptive has yet to be determined.

abstract: PhD


title: The Scatter Dependence of the Spatially-Resolved Star Formation Main Sequence Relation

contributor: Physics, Engineering Physics and Astronomy

subject:
galaxies: spiral
galaxies: star formation
galaxies: stellar content
galaxies: fundamental parameters
galaxies: photometry – surveys

abstract: The scatter of the spatially-resolved star formation main sequence (SFMS) is investigated in order to reveal signatures about processes of galaxy formation and evolution. We have assembled a sample of 355 nearby galaxies with spatially-resolved Hα and mid-infrared fluxes from the Survey for Ionized Neutral Gas in Galaxies and the Wide-field Infrared Survey Explorer, respectively. We examine the impact of various star formation rate (SFR) and stellar mass transformations on the observed SFMS. Ranging from 10^6 to 10^11.5 M⊙ and derived from colour to mass-to-light ratio methods for mid-infrared bands, the stellar masses are internally consistent within their range of applicability, given the systematic errors inherent to such transformations; a constant mass-to-light ratio (M∗/L_3.4μm = 0.5) also yields representative stellar masses. The various SFR estimates show intrinsic differences and produce noticeable vertical shifts in the SFMS, depending on the timescales and physics encompassed by the corresponding star formation tracer. SFR estimates appear to break down on physical scales below 500 pc. We examine the various sources of scatter in the spatially- resolved SFMS and find that morphology plays little or no role. We identify three unique tracks across the spatially-resolved SFMS by individual galaxies, demarcated by a critical stellar mass of log( M∗/ M⊙)∼8.5. Below this scale, the spatially-resolved SFMS shows no clear trend and is likely driven by local, stochastic internal processes. Above this scale, galaxies have comparable spatially-resolved SFMS slopes but exhibit two different behaviours, likely resulting from the mass accretion rate and/or quenching at the center of the galaxy. The effect of a bulge or AGN on these types must be considered. Additionally, we contrast these observational results with the study of 58 galaxy simulations by the NIHAO (Numerical Investigation of a Hundred Astrophysical Objects) project. We uncover the three unique tracks also in simulations, though they are not as prominent. While the local simulated SFMS matches observations fairly well, some of our more detailed comparisons point to deficiencies in the underlying physics that regulate the evolution of NIHAO galaxies.

abstract: M.Sc.


title: Creating a built-in suicide system in Adeno associated viral constructs as a safety check mechanism for treatment of possible tumor development in long term gene therapy studies.

contributor:
Walia, Jagdeep
Biomedical and Molecular Sciences

subject:
Suicide Gene Therapy
Gene therapy and safety mechanisms

abstract:
Adeno associated virus (AAV) is proving to be a powerful tool for gene therapy. However, a drawback of this tool reported in experimental studies is that a small percentage of the administered virus can integrate into host deoxyribonucleic acid (DNA) sequences, sometimes resulting in oncogenesis. Suicide gene therapy (SGT), a strategy for the gene-directed killing of cells, is one of the approaches that could be well utilized to augment existing gene therapies by providing a safety element in the event of tumor development. This technique has not been used in AAV based gene therapy experiments. One of the successful SGT systems utilizes Herpes Simplex virus thymidine kinase gene (HSVtk) which confers ganciclovir (GCV) sensitivity to the transduced cells. We hypothesized that placing HSVtk/GCV under the control of the HSP70 (Heat Shock Protein 70) promoter will results in apoptosis of HSVtk expressing cells, only when heat is applied.
	We developed a dual promoter-transgene AAV viral construct (AAV-70-tk-CAG-GFP) carrying an inducible HSP70 promoter for the expression of HSVtk and chicken β-actin (CAG) (a ubiquitous promoter), driving green fluorescent protein (GFP). Human embryonic kidney cells (HEK293 cells) were stably transfected with the study plasmid and analyzed for protein expression. The experimental and control cells were exposed to normal (37°C) and high temperature (41°C) to measure cell survival at different concentrations of GCV.
	The survival of stably transfected cells was markedly reduced with GCV treatment at 41°C, compared to untransfected HEK 293 cells. However, an unexpected decrease in cell survival was also noted at 37°C, indicating the promoter was also active at normal temperature. In summary, our experiment was the first step to test cell killing with SGT under the control of an inducible promoter in an AAV construct. The results showed cell killing both at high and normal temperatures. This provides a preface for future research exploring HSP70 induction physiology and use of other inducible promoters in the HSVtk/GCV suicide gene system.

abstract: M.Sc.


title: Use of (Super)Hydrophobic Surfaces in Digital Microfluidics

contributor:
Agrawal, Prashant
Chemistry

subject: Superhydrophobic, Digital microfluidics, Porous Polymer Monolith, Surfaces

abstract:
A superhydrophobic (SH) surface is characterized by a water contact angle of >150 and a sliding angle <10. The water fearing properties result from significantly stronger cohesive forces of the resting liquid compared to weak adhesive forces with the surface material. Microfluidics is a discipline in which minute liquid volumes (10–9 to 10–18 litres) are actuated, mixed, merged, split, and/or analyzed on uniquely engineered devices. SH surfaces have aided digital microfluidics by facilitating magnetic actuation of droplets and the spontaneous formation of droplet microarrays. SH surfaces offer low friction between a liquid droplet and the surface itself, allowing for actuation using minimal force. Magnetically susceptible material (paramagnetic salts or superparamagnetic particles) can be added to the droplet, making it possible to manipulate the liquid droplet with an external magnetic field.
This thesis focuses on the magnetic actuation performance of aqueous droplets on different SH coatings including Ultra-Ever Dry, (a commercial coating), fluorine-containing and more environmentally friendly “fluorine-free” SH porous polymer monolith (PPM). Droplet kinematic parameters are explored (e.g. volume, acceleration/deceleration, particle concentration etc.) SH surfaces can be patterned with hydrophilic regions to create surface energy traps (SETs). In this way, the liquid can be pinned to the SETs for small volume deposition and droplet anchoring, respectively. We utilize the contrasting wetting behavior to conduct a droplet-based quantitative DNA assay using fluorescence detection. Furthermore, we examine the use of patterned hydrophobic PPM surfaces to conduct an ice recrystallization inhibition assay that allows the side-by-side comparison of up to a dozen samples treated in an identical, higher throughput manner. A novel method of droplet manipulation is explored termed biologically-driven magnetic actuation (BDMA), which uses magnetotactic bacteria (MTB). BMDA is used to transport droplets along various trajectories (e.g. square and eight-shaped tracks). We further demonstrate the use of BMDA for sequential merging and mixing of multiple droplets. SH surfaces are typically limited to aqueous droplet manipulation.	Alternatively, slippery liquid-infused porous (SLIPS) surfaces have been shown to exhibit low friction for both organic and aqueous droplets. We demonstrate the magnetic actuation of aqueous and organic (hexadecane) droplets on SLIPS using paramagnetic particles. The sixth chapter of the thesis demonstrates the proof of principal application involving functionalized superparamagnetic particles for the extraction of asphaltenes from crude oil on omniphobic surfaces. This thesis successfully explains different ways (super)hydrophobic and SLIPS surfaces can be used for performing different DMF operations on aqueous and organic droplets.

abstract: PhD


title: Internet-based Planning in First Nations Communities: Challenges and Opportunities

contributor:
Whitelaw, Graham
Geography and Planning

subject: Internet

subject: Community Planning

subject: Indigenous Planning

subject: Public Engagement

subject: Digital Divide

subject: Decolonizing Planning

subject: Information and Communication Technologies

subject: ICT

abstract:
The growing use of the Internet in community planning has created enormous opportunities to improve community participation in Indigenous planning, overcome constraints associated with face-to-face based participation, and enhance the planning process. Understanding some of the potential barriers and challenges unique to using online participation is a critical step in moving towards establishing new best practices in Aboriginal community development across Canada.

The study was guided by a fundamental question: “How are First Nations communities using online tools to enable residents to more actively participate in the planning of their community?” The following are more specific research objectives set in the study: (a) to examine, through an extensive review of the relevant literature, the role that on-line tools can play in facilitating greater participation of First Nations residents in their community development; (b) to explore the various aspects of ICT that are relevant within the context of Indigenous land use planning; (c) to assess, through an examination of five case studies, the extent to which on-line tools are currently being utilized by First Nation residents in planning their communities; and (d) to suggest how on-line tools can be improved to enable First Nations residents to more actively participate in the planning of their community. Case studies included: Fort Severn First Nation, Mississaugas of the New Credit First Nation, Whitefish River First Nation, and Shawanaga First Nation, all in Ontario; as well as Nak'azdli Whut'en First Nation in British Columbia.

A working conceptual framework was developed to explore the role that ICT plays in planning in First Nations communities. In addition, challenges and opportunities associated with an evident “digital divide” (the economic and social inequality with regards to access to and use of ICT) was identified between First Nations and other communities in Canada, providing further constraints to the Indigenous planning process. Findings from the study show clear evidence that ICT played a positive role in enabling citizen participation in public engagement. However, it was found that First Nations residents were not fully involved in the decision-making process and were not fully empowered in making any final decisions.

abstract: M.PL.