title: Preliminary Investigation into the Vibration Characteristics and Isolation Requirements of a Prototype MRI Scanner

contributor:
Mechefske, Christopher K.
Mechanical and Materials Engineering

subject: MRI Vibrations Isolator

abstract:
Magnetic Resonance Imaging (MRI) is a powerful diagnostic and research tool, used extensively in diagnoses of brain diseases, musculoskeletal disorders or damage, and an- giography. A persistent issue with MRI machines is inadequate vibration isolation. The vibration isolation issue is two-faceted. First, the scanner produces significant noise and vibrations during operation which, when transmitted to the machines environment, have negative repercussions such as the production of acoustic noise. Second, any motion of the scanner due to environmental factors will produce noise in the image, thereby limiting the resolution that can be achieved by the scanner.

The objective of the present work is to implement passive vibration isolation in the base structure of a prototype MRI scanner. The first step to accomplishing this is the creation and validation of a finite element (FE) model of the MRI base, which requires computational and experimental modal analysis. The natural frequencies and mode shapes of a model of the MRI base up to 600 Hz were calculated computationally using ANSYS and experimentally with a shaker modal test. Seven mode pairs were visually correlated between experimental and computational data. Thus far, subjectively good correlation has been achieved.

Following this, the model is used to simulate isolator performance in conjunction with further experimental testing of vibration isolator alternatives. A small scale test of the pneumatic isolator demonstrates that the specific isolator type performs well under the MRI loading conditions, and establishes a testing protocol for future testing. Furthermore, on-site testing that compares the performance of the full-sized pneumatic isolator installed on a scanner against a scanner mounted on aluminium blocks. The isolators were found to perform well, but do not meet the design requirements. Lastly, the pneumatic isolators are modelled in ANSYS to evaluate their performance in the worst case scenario (isolator resonance). A Matlab script and the ANSYS model are used in conjunction to calculate optimal stiffness and damping coefficients.

abstract: M.A.Sc.


title: Experimental and Numerical Investigation of Snow Removal From Photovoltaic Solar Panels

contributor:
Harrison, Stephen
Oosthuizen, Patrick
Mechanical and Materials Engineering

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:
Photovoltaic Solar Panels
Snow Removal
Heating Method

abstract:
A key challenge to the wide-scale implementation of photovoltaic solar panels (PV) in cold and remote areas, is dealing with the effects of snow and ice buildup on the panel surfaces. However there currently is no practical mechanism to remove snow-cover from PV surfaces and long shut-down periods occur for plant operators. The objective of this study is to evaluate different types of heating snow removal systems for PV modules and to present methodologies and tools to improve PV systems modelling and output prediction.
A numerical model is presented to predict thermal snow removal from a PV panel. The model can predict snow melting or snow sliding from horizontal and inclined panels. A set of experiments was conducted using a small-scale PV panel in a freezer to provide a correlation for snow sliding from the panel. The correlation was implemented in the model to predict snow sliding situations.
To validate the model and study thermal snow removal from a full scale PV panel, outdoor tests were conducted under natural conditions including different snowfall conditions. Two heating methods were investigated: embedding an electrical resistance heater to the back of the panel and imposing a reverse current through the solar cells. The results showed that ice dam and icicles formation at the bottom of the panel prevented the snow cover from sliding off the panel. In addition, the effect of heating the entire panel surface or partially heating the panel was investigated.
An insulation equipped with a venting channel were proposed to use for the PV panels. This insulation improves the performance of snow removal from the panels, while having a minimum effect on the panel performance during a regular sunny day. To enhance the snow removal from the panel, the vents would be closed while opening the vents enhance the heat transfer from the panel during a sunny day. Radiation heat transfer between the panel and the insulation was also improved by coating the insulation. Outdoor tests were conducted under natural condition to study the performance of the proposed insulation during hot summer days. In terms of panel temperature and power output, the results showed promising improvement compared to using a single insulation without any modifications and especially without vents.
Finally, it was proposed to remove snow from photovoltaic-thermal panels (PV/T) by circulating hot fluid through the back of a panel. Conducting outdoor tests revealed that this method can clean the panel from snow in a short period of time. The experimental results were compared with the results given by the numerical model presented in this study. To compare the required energy for snow removal with the amount of energy generated by the panel after snow removal during a day, a non-dimensional number was proposed. Using this number and conducting a case study showed that this snow removal method can be beneficial for the PV and PV/T systems.

abstract: PhD


title: "Time is Money":  Examining the Influence of Temporal Focus Across the Adult Lifespan

contributor:
Ji, Li-Jun
Psychology

subject:
psychology
aging
organizational behavior
consumer behavior
time

abstract: Seniors represent the fastest growing demographic in Canada. Internationally, it is projected that the world’s senior population will continue to increase over the next several decades. Thus, more research is needed in order to better understand the specific needs and motives of this important age group. The present research documents how the concept of time influences the thoughts, preferences, and behavioral intentions of older and younger adults. Study 1 reported that older adults devoted significantly more attention towards the present compared to the past and future, while younger adults showed a small preference towards the future. Moreover, older adults’ reduced sense of time remaining in life led to them devoting less time to the future. Surprisingly, sense of time remaining in life also significantly suppressed the relationship between age and present temporal focus. That is, an increased sense of time remaining in life was actually associated with more present focus among seniors. Study 2 investigated the downstream consequences of temporal focus by examining older and younger adults’ motivation for present- and future-focused jobs in the organizational behavior context. Findings revealed that older adults showed a distinct preference for present-focused job opportunities over future-focused ones, whereas younger individuals reported the opposite pattern. In Studies 3 and 4, we moved beyond mental investment in different temporal periods and examined how older and younger adults’ views towards the past and the future influenced their preferences and choices in a consumer behavior context. Results from Study 3 indicated that older adults responded more favorably to persuasive advertisements presented with a past focus compared to future-focused and control ads (i.e., no temporal focus), while younger adults actually rated the control ads higher than both the past- and future-focused ones. Furthermore, positive general views of the past mediated the relationship between age and preferences past-focused advertisements. Finally, Study 4 reported that the findings observed in Study 3 were associated with overt differences in behavioral intentions within a hypothetical purchasing scenario. Specifically, older adults opted for a past-focused product more frequently (68%) than a future-focused product (32%), with younger adults showing no distinct pattern in their choices.

abstract: PhD


title: Influence of Environmental Risk Factors of Colorectal Cancer and Gene-Environment Interactions on Line-1 DNA Methylation

contributor:
King, Will
Public Health Sciences

subject:
Epidemiology
Colorectal Cancer
DNA Methylation

abstract:
Introduction: This study examined the association between established colorectal cancer (CRC) risk factors and LINE-1 DNA methylation in healthy colon tissue, and whether genes involved in one-carbon metabolism modify relationships between established CRC risk factors and LINE-1 DNA methylation. This study was undertaken in order to inform on the role of LINE-1 DNA methylation as a mechanism by which established risk factors may lead to carcinogenesis. Reduced LINE-1 DNA methylation and one-carbon metabolism-related gene variants are both shown to increase CRC risk. Exposures related to LINE-1 DNA methylation may have a greater effect on methylation levels for individuals already susceptible to reduced methylation due to possession of a genetic variant. When considered together, these effects may impact methylation patterns in individuals beyond what would be expected if effects were purely additive.
Methods: The study population consisted of 317 individuals scheduled for a routine colonoscopy. Multivariable linear regression was used to study the associations of alcohol consumption, smoking, body mass index, non-steroidal anti-inflammatory drug use, physical activity, and fruit and vegetable consumption with LINE-1 DNA methylation. Product terms between MTHFR 677C>T (rs1801133), MTR 2756A>G (rs1805087), and MTRR 66A>G (rs1801394) genotypes and exposures of interest were used to examine effect modification by genotype.
Results: There were no statistically significant relationships observed between each risk factor of interest and LINE-1 DNA methylation. Statistically significant interactions between alcohol consumption and MTHFR and MTR genotypes were observed (p-value interaction=0.009, 0.003) in relation to LINE-1 DNA methylation.
Conclusion: This thesis presents novel results on the relationships between a comprehensive set of CRC risk factors and LINE-1 DNA methylation in healthy colon tissue. We observed significant interactions by gene variants in the relationships between CRC risk factors and LINE-1 DNA methylation in the healthy colon. Although effects were not consistently in hypothesized directions, they suggest that one-carbon metabolism-related gene status is an important effect modifier in the relationship between alcohol consumption and LINE-1 DNA methylation.

abstract: M.Sc.


title: Staying a Woman, Becoming a Patient: Experiences of Breast Cancer, Gender and Identity in Neoliberal Turkey

contributor:
King, Samantha J.
Cultural Studies

subject:
breast cancer
neoliberalism
patient identity
gender identity

abstract: Drawing on ten interviews, this thesis explores the perspectives and practices of women with breast cancer in contemporary Turkey. My analysis focuses on two key areas: the gendered nature of intimate and family relationships, embodiment, and work during the breast cancer experience; and the formation of new patient identities as the Turkish breast cancer “regime” shifted from the 1990s/early 2000s to the 2010s. My overall argument in this thesis is that the maintenance of a normative gender identity, “staying a woman”, and the navigation of a changing healthcare system, “becoming a patient,” play a crucial role in how women experience breast cancer in a neoliberal environment.

abstract: M.A.


title: Evaluation of Carbon Monoxide as a Therapeutic for Preeclampsia

contributor:
Smith, Graeme N
Anatomy and Cell Biology

subject:
Preeclampsia
Pregnancy
Carbon monoxide

abstract:
Preeclampsia (PE), a hypertensive complication of pregnancy, is one of the leading causes of maternal and neonatal morbidity and mortality. The etiology of PE is not well-understood, however it is widely accepted to occur in two stages: poor uteroplacental perfusion and placental ischemia, which subsequently leads to a systemic maternal inflammatory response and multi-organ effects. Although cigarette smoking during pregnancy is known to cause aberrant placental development and adverse pregnancy outcomes, smoking reduces the risk of PE by 33% in a dose-dependent manner. The same risk reduction does not hold true for users of smokeless tobacco products. This has lead to the notion that carbon monoxide (CO), one of the byproducts of cigarette combustion, may confer this decrease in PE risk. Endogenously, CO is produced through the degradation of heme by heme oxygenase (HO), and it has been suggested that modulation of the HO/CO system may attenuate the development or progression of PE.
The studies presented herein demonstrate that low doses of CO, delivered through gaseous CO or CO donor molecules, may exhibit physiological benefits and have therapeutic potential during complicated pregnancies. Firstly, the challenges associated with reproducing the AdsFlt-1-induced mouse model of PE for studying the effects of CO in complicated pregnancies were investigated. Clinically, inhaled CO was shown to moderately increase biological CO above endogenous levels, and increase vascular responses in the cutaneous microvasculature. In mice, it is demonstrated that the CO-releasing molecule (CORM-A1) is able to transiently increase biological CO levels. CORM-A1 delivered in mid-gestation, resulted in increased CO, without adverse maternal or fetal effects, indicating the potential for CORM-A1 as a novel method to deliver CO during pregnancy. Collectively, the data presented in this thesis verify that low dose CO may have therapeutic properties to improve endothelial dysfunction, increase placental perfusion, and reduce progression of the clinical signs of PE.

abstract: PhD


title: The development and validation of a cultural competency model for health care providers working with military and Veteran families in Canada

contributor:
Cramm, Heidi
Krupa, Terry
Rehabilitation Science

subject:
Military Family Health
Cultural Competency
Health Care Practice
Model Development and Validation

abstract:
Objectives. Canadian military and Veteran family life is characterized by frequent relocation, regular familial separation due to training or deployment, and living with the risk of injury or death of a military family member. Most Canadian health care providers lack knowledge and skills to address these issues. Therefore, the purpose of the thesis was to develop and validate a cultural competency model for health care providers working with military and Veteran families.
Methods. The thesis consisted of three phases. Phase One was a scoping review of health care literature to identify commonalities in the content, structure, and development of cultural competency models. Phase Two used competency framework development methodology to create a military and Veteran family model and framework. Data collection included interviews with military and Veteran family members (n=17) and health care providers (n=9). In Phase Three, a validation study was conducted of the proposed model using focus groups and interviews with military subject matter experts (n=12) and health care providers (n=8).
Results. Based on population-specific data, the Military and Veteran Family Cultural Competency Model and framework was created that includes 24 cultural competencies articulated across four cultural competency domains.
Conclusion. The thesis has identified and validated cultural competencies for health care providers working with military and Veteran families within the Canadian health care landscape. This validated model may help inform health provider education and professional development programs to increase awareness, knowledge, and skills to enhance the health experiences and health outcomes of military and Veteran families.

abstract: PhD


title: Atmospheric Leaching of Enargite in the Presence of Carbon Based Catalyst

contributor:
Ghahreman, Ahmad
Mining Engineering

subject:
Leaching
Enargite
Arsenic
Atmospheric Leaching
Catalyst
Activated Carbon
AF 5
Scorodite
Copper

abstract:
Pyrometallurgy is not the most sustainable option for enargite concentrate treatment due to the environmental limitations on arsenic release. Therefore, developing an effective hydrometallurgical process is a promising solution for enargite treatment. Most hydrometallurgical processes proposed in literature have not reached commercial utilization because of common issues such as slow dissolution rate of the mineral, incomplete copper or precious metals recovery, sulfate generation, arsenic fixation problems, and high capital and operating costs.
In this thesis, the atmospheric leaching of enargite in chloride media was investigated in the presence of activated carbon (AC) and AF 5, a novel carbon based catalyst. Both catalysts were found to be very effective in facilitating the enargite leaching process and improved the oxidation and copper recovery from 65% to 92% (AC) or 96% (AF 5) after 96 hours. The best leaching condition was found to be: ferric and cupric concentrations greater than 5 g/L, concentrate to catalyst mass ratio of 1:2, and a 90 °C working temperature or higher. The elemental sulfur product of the leach reaction did not coat the surface of the partially leached mineral particles. When AF 5 was used as the catalyst in the leaching process, it collected the generated elemental sulfur. The arsenic also precipitated in the form of scorodite, one of the most stable forms of arsenic, during the leaching in chloride media at temperatures higher than 80 °C. The catalytic properties of the carbon-base catalysts (CBC) was due to the oxidation via oxygen functional groups on their surfaces, which were detected by XPS analysis.
The results showed that the chemical pre-treatment of CBC can be effective in increasing its catalytic effect on enargite leaching. The comparison between the chloride and sulfate media showed that the sulfate media has better copper and iron dissolution kinetics and promotes sulfur collection, whereas the remediation of arsenic in the form of scorodite can be superior in chloride media.

abstract: PhD


title: Calpain-1 and Calpain-2 Promote HER2/NEU Tumorigenesis and Independently Promote Metastasis in Triple Negative Breast Cancer

contributor:
Greer, Peter
Pathology and Molecular Medicine

subject:
calpain
HER2
NEU
triple negative breast cancer
breast cancer

abstract: Calpains are a family of calcium activated cysteine proteases. Calpain-1 and calpain-2 are obligate heterodimers composed of isoform specific catalytic subunits (encoded by capn1 and capn2, respectively) coupled with the common, shared regulatory subunit calpain small subunit 1 (encoded by capns1). Here, we report a role for these calpains in promoting spontaneous tumor onset in a model of human HER2+ breast cancer, as well as a requirement for these calpains for tumor viability in an orthotopic engraftment model. Furthermore, we demonstrated that knockout of capns1 correlated with enhanced sensitivity to the chemotherapeutic doxorubicin, the EGFR/HER2 inhibitor lapatinib, and sustained MAPK signaling in response to EGF. In a model of triple-negative breast cancer we demonstrate that CRISPR/CAS9-mediated knockout of calpain-1 (capn1) or calpain-2 (capn2) independently attenuated metastatic colonization in vivo, and that knockout of either isoform was associated with attenuated production of MMP-9. Collectively, our results suggest a pro-tumorigenic role for calpain-1/2 in both HER2+ and triple-negative breast cancer, which provides preclinical evidence in support of combining calpain inhibitors with commonly used therapeutic drugs.

abstract: PhD


title: Examining the natural and disturbed behaviours of Alewife (Alosa pseudoharengus) using hydroacoustic surveys in Lake Ontario

contributor:
Tufts, Bruce
Biology

rights: Attribution-ShareAlike 3.0 United States

subject:
Alewife
Lake Ontario
Hydroacoustics
Behaviour
Boat Avoidance
Assessment

abstract: In Lake Ontario, Alewife are the primary prey for salmonids, which provide a popular and socio-economically important recreational fishery. There is concern with regards to whether the Alewife population has the ability to support the predatory demand in Lake Ontario after a crash in the Alewife and predator populations occurred in Lake Michigan. To avoid such a crash, it is imperative that agencies working on Lake Ontario have accurate methods of assessing fish populations. Mobile hydroacoustic surveys of the lake began in 1991 as a method to assess the Alewife population, however, there is growing concern about the accuracy of these estimates. Fish in hydroacoustic surveys can appear to be smaller when oriented off-axis, as is common with fish displaying boat avoidance behaviour. The mobile assessment estimates are made using size thresholds to classify targets in the survey and Alewife which are diving may be appearing too small to be correctly classified. Using information from mobile, as well as stationary up-looking surveys, this study assesses how Alewife react to the survey vessel, and how the reactions may be impacting their observed target strength. The results indicate that Alewife are observed at smaller sizes in the mobile survey than would be expected. The mobile survey observed fish at deeper depths and the behaviour of the fish was indicative of boat avoidance. Fish from the mobile survey swam faster and more linearly than fish from the stationary survey. Consecutive targets in tracks from the mobile survey also increased in depth with a more negative track tilt. There were no strong predictors of changes in target strength tested with linear models which could be used as correction factors in the current dataset. In future studies, analysis of variables such as the true orientation of the fish may provide appropriate correction factors for this type of data. The current survey approach provides a valuable index of “relative” Alewife abundance from year to year, however, additional research will be required to provide more accurate estimates of the absolute abundance of Alewife in Lake Ontario.

abstract: M.Sc.


title: New Borylation Strategy for the Construction of Borylated Heterocycles and Bodipy Derivatives

contributor:
Wang, Suning
Chemistry

rights: Attribution-NonCommercial 3.0 United States

subject: Boron Chemistry

abstract:
This thesis mainly concerns: (1) developing new borylation strategies for heterocycles through addition of a B-E σ bond (E = H, N) across internal alkynes; (2) synthesizing BODIPY derivatives with interesting properties via “pre-functionalization” strategy; (3) preparing boron-based stimuli-responsive compounds for fluoride sensing.

The hydroboration of alkynes is known to proceed in a cis-fashion. Catalytic trans-hydroboration has been established in the past decade while catalyst-free trans-hydroboration was unknown. In the study of hydroboration reactions, an unexpected pyridine-directed trans-hydroboration of internal alkynes was disclosed and presented. This transformation could serve as a facile method to construct novel luminescent N,C-chelate organoboron compounds.

In the study of the amine directed hydroboration reaction, a facile dehydrogenative coupling between alkynyl aryl amines and 9-BBN was discovered. Based on the dehydrogenated products, a catalytic trans-aminoboration of internal alkynes was designed to give borylated indole derivatives. The reaction scope to different boranes and anilines was surveyed to generate a variety of borylated indoles.

The dehydrogenative coupling of arylamines with 9-BBN described above represents a convenient method to construct a B-N covalent bond. By switching 9-BBN to monosubstituted boranes, a family of novel azaborabenzofulvenes was obtained by exploiting sequential dehydrogenative hydroboration of alkynyl arylamines. Both the reaction scope and the properties of the products were studied.

Boron-dipyrromethene (BODIPY) and derivatives are excellent luminophores with bright emission in dilute solutions. However, they are rarely emissive in the solid state. In chapter 5, several spiro-BODIPYs with the “pre-functionalization” strategy were prepared. The spiro-structure successfully precludes the formation of π-stacking and leads to efficient solid state emissions. More interestingly, the spiro-BODIPYs formed J-aggregates in methanol-water mixed solvents.

With the same strategy, a ferrocene functionalized BODIPY featuring direct Fc-B bond was prepared. Detailed studies on the novel compound and its analogues indicate the importance of ferrocenyl substituents and the bridge on their excited-state properties of BODIPY molecules.

Trivalent organoboranes have been explored as fluoride sensors by monitoring fluorescence change, which is inconvenient in practical applications. In chapter 7, a family of boron functionalized poly-ferrocene compounds were prepared and some of these molecules can be used for colorimetric fluoride sensing.

abstract: PhD


title: Solid-State 17O NMR, Crystallographic, and Computational Studies of Epoxides and Related Molecules

contributor:
Wu, Gang
Chemistry

subject:
Solid-State NMR
Physical Chemistry
Computational Chemistry
X-Ray Crystallography
Chemical Physics
Spectroscopy

abstract: The aim of this thesis was to study quadrupolar nuclei using solid-state 17O NMR spectroscopy, X-ray crystallography, and computational methods. This thesis reports the successful synthesis and characterization of three 17O-labelled epoxides, [17O]-(2S*,3S*)-2,3-bis(4-nitrophenyl)oxirane, [17O]-(2S*,3R*)-2,3-bis(4-nitrophenyl)oxirane, and [17O]-2,2,3-triphenyloxirane. The 17O NMR tensors (measured using solid-state 17O NMR spectroscopy and calculated using computational methods) and structural parameters (measured using single crystal X-ray crystallography and calculated using computational methods) of the three epoxides were compared. The dependence of ethereal 17O NMR tensors on bond geometry was computationally analyzed. A new model for visualizing quadrupolar coupling tensor components using valence p-orbital population anisotropies was also developed. This model is a simple adaption to the Townes-Dailey method that allows for the visualization of each quadrupolar coupling tensor component (χii ii = xx, yy, zz) using only a single parameter (ΔPii), whereas the traditional Townes-Dailey method requires three parameters. This new model was demonstrated to deliver comparable quadrupolar coupling tensor components to those calculated using direct g09 NMR calculation methods for 14N, 17O, and 127I. Finally, iodosylbenzene, a candidate for containing the strongest halogen bonds, was studied using solid-state 17O NMR and computational methods. Using computational methods, its σ-hole was quantified and its magnitude was compared to that of other halogen bond donors.

abstract: M.Sc.


title: Are Intensities, Types, or Patterns of Movement Behaviours Most Strongly Associated With Cardiometabolic Risk Factors Among Children?

contributor:
Janssen, Ian
Kinesiology and Health Studies

subject:
Children
Movement Behaviours
Cardiometabolic Health
Active Play
Sleep
Sedentary Behaviour
Physical Activity
Public Health

abstract: Purpose: The way children move over the entire 24-hour day influences their health. The purpose of this study was to determine which intensities, patterns, and types of 24-hour movement behaviours are most strongly associated with cardiometabolic risk factors among children. Methods: A total of 369 children aged 10-13 years were studied. Participants wore an Actical accelerometer, a Garmin Forerunner 220 GPS logger, and completed an activity and sleep log for 7 consecutive days. Data from these instruments were combined to estimate the average minutes/day spent in 14 intensities, 11 types, and 14 patterns of movement while sleeping and engaging in sedentary behaviour and physical activity. Body mass index, resting heart rate, and systolic blood pressure values were combined to create a cardiometabolic risk factor score. Partial least squares regression analysis was used to examine associations between the 39 movement behaviour characteristics and the cardiometabolic risk factor score. The variable importance in projection (VIP) values were used to determine and rank important movement behaviour characteristics. There was evidence of interaction by biological maturity and analyses were therefore conducted separately in the 50% least and 50% most mature participants. Results: For the least biologically mature participants, 15 of the 39 movement behaviour characteristics had important VIP value scores; eight of these reflected movement intensities (particularly moderate and vigorous intensities), six reflected movement patterns, and one reflected a movement type. For the most biologically mature participants, 13 of the 39 movement behaviour characteristics had important VIP value scores, with five reflecting intensities (particularly moderate and vigorous intensities), five reflecting patterns, and three reflecting types of movement. Conclusion: These findings suggest several different movement behaviour characteristics are associated with children’s cardiometabolic health. Time spent in movement intensities within the moderate and vigorous intensity ranges appear to be the most important movement behaviour characteristics for cardiometabolic risk factors.

abstract: M.Sc.


title: Performance of Trenchless Rehabilitations for Culvert, Sewer, and Maintenance Hole Structures

contributor:
Moore, Ian
Hoult, Neil
Civil Engineering

subject:
Erosion void
Rehabilitation
Deterioration
Liners
Pipes
Maintenance holes

abstract:
Deterioration and rehabilitation impacts on buried infrastructure were explored using experimental methods. Deterioration studies included the effects of erosion voids (in the immediate backfill) on steel and reinforced concrete pipe behaviour. Additionally, the voids were rehabilitated using simple trenchless solutions and the impact on pipe capacity was explored. Furthermore, rehabilitation is also commonly performed on access structures (i.e. maintenance holes) to restrict leaks rather than restore structural capacity; and this ability of the repaired system to sustain further leaks was also explored.
A corroded steel pipe buried with an erosion void simulated on one side, was tested under simulated service loads. This revealed that the void appeared to compromise the stability of the structure. Rehabilitation of the culvert with a high density polyethylene slip liner and a low density, low strength grout lowered the strains in the host pipe. Strains measured before 300 kN applied load suggests that the grout had not fractured, and the steel pipe, liner, and grout responded as a composite system. After 300 kN, the grout appeared to fracture, and the strains in the steel pipe and liner accelerated with applied load.
The impact of erosion voids and rehabilitated voids (filled with low strength, low density grout), of varying sizes, on the live load responses of reinforced concrete pipes were also studied. The changing pipe responses were quantified using modified bedding factors (Bf). Erosion voids increased the overall pipe bending moments, especially at the invert; grouting both the larger and smaller voids reduced the increases in invert moment.
For sprayed liners installed within maintenance holes, the primary loads result from groundwater infiltration. Testing protocols and equipment were developed to monitor leakage resistance of the sprayed liners, simulating different sized areas with poor bond between the liner and the substrate. For the specific liner system investigated, circular zones with poor bond resulted in water loss after ‘peeling’ failure (water pressure acted to lift the circular zone with poor bond off the substrate around its circumference). The peeling per unit circumference was found to be a constant, independent of the diameter of the circular area with poor bond.

abstract: PhD


title: The “Hippocratic” Stance on Abortion: The Translation, Interpretation, and Use of the Hippocratic Oath in the Abortion Debate from the Ancient World to Present-Day

subject: Hippocratic Oath abortion medicine ancient medieval contraception

abstract: The Hippocratic Oath was written in the fourth or fifth century BCE and was an esoteric document until hundreds of years after its creation. Physicians were not required to be familiar with this document in the ancient world, and its prominence in later history was mainly due to its association with Hippocrates, though the famous doctor is likely not its author. The document was adopted in the medieval and renaissance periods, however, and adapted to conform to Christian ideals that physicians were expected to abide by. In present-day society the oath has been used in legal trials such as Roe versus Wade, and continues to be used by many pro-life associations to argue that abortion should not be permitted under any circumstances. It is the purpose of this essay to examine the oath’s stance on abortion in the context in which it was written, to reinforce the fact that it largely disagreed with moral and medical standards which existed prior to the rise of Christianity. This is demonstrated through an examination of the use of the oath by physicians in antiquity as well as the medieval period, changing moral and religious concerns with induced miscarriage, and laws associated with abortion throughout the procedure’s history in relation to changing cultural norms. Though the intended meaning of the line in question may be uncertain, it is clear that abortion was an accepted procedure in medical circles in antiquity, and that the adoption and use of the Hippocratic Oath to advance pro-life argumentation was aided by changing social, moral, medical, and religious beliefs.


title: Dynamic Large-Scale Graph Processing over Data Streams with Community Detection as a Case Study

contributor:
Zulkernine, Farhana
Computing

rights: Attribution-NonCommercial-ShareAlike 3.0 United States

subject:
Big Data
Analytics
Graph Processing
Community Detection
Spark
Stream Processing
Real-time Processing

abstract:
Processing large graphs provides invaluable insights for the industry and research alike. The applications range from e-commerce, web, and social networking to analyzing gene expressions and cellular signaling. While numerous graph processing solutions have been developed with the capability to process graphs at the scale of a trillion edges, the ability to maintain and process a real-time graph still far from being handled. Processing data streams in real-time requires the graph to change over time which introduces several new challenges. First, the graph needs to be updated from the data stream efficiently. At the same time, applying these changes should not add an unacceptable overhead to graph queries. In addition, these changes need to be reflected in the new analytical insights, otherwise the value of the insights degrades with time.
In this work, we investigated the problem of dynamic graph processing over data streams. We started by studying the feasibility of maintaining a dynamic graph on top of Apache Spark, a data processing engine. The chosen solutions included RDDs, IndexedRDDs, and Redis. Results from our experimental indicated that Redis performed the best, and thus we concluded that storing the graph in an external big data store besides Spark is the best approach in terms of performance and practicality. After that, we designed and developed Sprouter, a streaming data analytics framework which utilizes Apache Spark for dynamic graph processing. The framework enables storing enormous graph data, allows real-time graph updates, and supports efficient complex analytics and OLTP queries. Experiments showed that the system is able to support the above mentioned properties and update graphs with up to 100 million edges in under 50 seconds in a moderate underlying cluster. Finally, we selected community detection as a case study of incremental graph analytics with Sprouter. We proposed the Incremental Distributed Weighted Community Clustering (IDWCC), a novel algorithm that optimizes the Weighted Community Clustering metric to detect communities in unweighted undirected node-grained dynamic graphs. We validated the algorithm against the static centralized and distributed versions of WCC optimization. The experiments showed that the performance of IDWCC surpasses the static distributed version by up to three times while maintaining the same accuracy or better.

abstract: M.Sc.


title: Intragenic Rescue of the Function of Long QT Syndrome-Causing Mutant hERG K+ Channels

contributor:
Zhang, Shetuan
Biomedical and Molecular Sciences

subject: hERG Mutations

abstract: The human-ether-a-go-go-related gene (hERG) encodes the pore forming subunit of the rapidly activating delayed rectifier K+ channel (IKr), which is important for the repolarization phase of ventricular cardiac action potentials. A reduction in IKr due to a loss of hERG function can lead to long QT syndrome (LQTS). As such, there are a variety of hERG mutations known to cause LQTS. The majority of these mutations are thought to be trafficking deficient, including the G601S mutation. It has been shown that the plasma membrane (PM) expression of the G601S hERG mutant can be rescued by reduced-temperature culture. Additionally, it has been shown that hERG channels undergo rapid internalization in 0 mM K+o culture conditions, but this can also be prevented by reduced-temperature culture. Thus, the hypothesis of this thesis is that certain hERG mutants, including G601S, can traffic to the plasma membrane where they internalize due to impaired stability, similar to WT hERG channels in 0 mM K+ conditions. To test this hypothesis, a secondary mutation, S624T, which does not require K+o for stable PM expression, was added to the G601S mutant hERG channel. The addition of S624T intragenically suppressed the loss-of-function G601S phenotype and significantly rescued G601S expression and current. The addition of S624T also rescued LQTS-causing hERG mutants T474I and P596R. These data reveals the most effective intragenic rescue of LQTS-causing hERG mutants to date and lends insight into the mechanisms underlying the loss-of-function phenotype of certain LQTS-causing hERG mutants.

abstract: M.Sc.


title: Distributed sensing to assess the effect of axial restraint on reinforced concrete slabs

contributor:
Hoult, Neil
Civil Engineering

subject:
reinforced concrete
axial restraint
distributed sensing

abstract:
Current design codes do not account for effects such as arching and membrane action in reinforced concrete slabs, which can increase capacity, and allow for a reduction of construction materials to be used. Research conducted to date has been unable to measure stress distribution throughout reinforced concrete slabs to fully understand the impact of arching and membrane action, because a method for capturing distributed strains was previously unavailable. One solution is to use distributed monitoring technologies to evaluate slab behaviour. Distributed fibre optic sensors (FOS) based on measuring Rayleigh backscatter provide strain measurement along the full length of the fibre up to 70 m. An experimental study using this technology was undertaken to investigate the behaviour of reinforced concrete slabs subjected to axial restraint.
In the first test series, eleven one-way reinforced concrete slabs with varying depths, reinforcement ratios, and boundary conditions were instrumented with nylon coated FOS and tested in three-point bending to investigate the effects of axial restraint on slab behaviour. It was found that axial restraint increased the load carrying capacity of the specimens up to 45% and reduced reinforcement strains at a given applied load prior to yielding. An increase in capacity and decrease in reinforcement strains at a given load were also seen as reinforcement ratios and slab depths were increased. All specimens failed in flexure.
In the second test series, four two-way reinforced concrete slabs with varying reinforcement ratios and boundary conditions were instrumented and tested under a central point load. Increasing the reinforcement ratio led to an increase in slab capacity up to 45%. Two specimens failed in flexure and two failed due to punching shear.
Finite-element models were created for the one-way specimens to evaluate the accuracy of the models for use in structural assessment with distributed sensing. Plastic collapse analysis was completed for the two-way specimens in order to determine the accuracy of the analyses. Results from the FE model were accurate for the control specimens but showed stronger and stiffer responses compared to the restrained specimens. The plastic collapse analyses estimated the experimental control capacity within 13%.

abstract: M.A.Sc.


title: Income, Patient Enrolment Model and Cervical Cancer screening uptake within the Central East Local Health Integration Network

contributor:
Edge, Dana
Nursing

subject: income

subject: patient enrolment model

subject: PEM

subject: cervical cancer screening

subject: age

subject: enrolled

subject: attached

subject: lower socioeconomic status

subject: SES

subject: PAP

subject: health inequity

abstract:
Cervical cancer screening detects cancer at early stages and is available to Ontario women ages 21 to 69 years of age. Notwithstanding cancer screening initiatives, sub-groups of Ontario women are under-screened based on current literature.  The most common primary health care delivery system in Ontario are patient enrolment models (PEMs) which allows for physician-incentives when rostering and cancer screening benchmarks are met. Notwithstanding, little is known about the effect of PEM enrolment and other socioeconomic (SES) factors, such as income, on screening uptake. This study considered differences in cervical screening uptake by PEM status and neighbourhood income levels by women residing in the Central East Local Health Integration Network (CELHIN).

A descriptive, comparative study using record level, administrative data from Cancer Care Ontario of eligible CELHIN women between January 1, 2012 and June 30, 2015 was conducted (N=490, 574). The variables of interest were cervical screening uptake (dependent variable), PEM status (primary exposure variable), neighbourhood income quintile (independent variable) and controlled for age and rurality.

Using logistic regression, it was determined non-enrolled women were more likely not to be screened (OR =6.98, 95% CI, 6.87-7.08) compared to enrolled women, representing the strongest association.  Given heterogeneous effects in odds ratios, multivariate stratified logistic regression analyses were undertaken for PEM enrolled and non-enrolled women separately. A significant association was found between older, non-enrolled women (ages 60-69) and not being screened (OR=1.87, 95% CI, 1.78-1.96). Unexpectedly, enrolled women in the lowest neighbourhood income quintile were more likely to not be screened (OR=1.49, 95% CI, 1.46-1.53) compared to their non-enrolled counterparts (OR=1.20, 95% CI, 1.14-1.25).  Urban dwellers were slightly less likely to be screened (enrolled women: OR=1.10, 95% CI, 1.07-1.12; non-enrolled women, OR=1.06, 95% CI 1.01-1.11) relative to rural women.

As older women have the greatest risk of high-grade invasive cervical cancer and PEM status is not protective for women living in lower SES, the priority for the CELHIN should be addressing barriers to cervical screening uptake, regardless of PEM status, for marginalized at-risk women including older women, and women living in lower SES environments.

abstract: MNSc.


title: Chiral N,C-Chelate Organoboron Compounds: Photoreactivity and Optoelectronic Applications

subject: Organoboron Photochemistry Photochromism Photoisomerization OLEDs

abstract: The works described herein are broadly concerned with exploring the interactions between light and boron-containing π-conjugated systems in order to build a complete understanding of the relationship between molecular structure and reactivity. Despite rapid progress in the field of N,C- and C,C-chelate organoborate photochemistry over the past ten years, only the effects of different π-conjugated backbones have been well documented, with the impact of the aryl substituents being virtually unknown. To remedy this deficiency and harness the full potential of this class of photochromic materials, methodologies for obtaining prochiral organoboranes and their respective chiral N,C- or C,C-chelate organoborates have been developed in order to investigate the influence of boron substitution on their excited-state reactivity. Chiral N,C-chelate organoboron compounds bearing two different aryl groups at the boron center have been found to undergo regioselective photoisomerization involving the less bulky substituent exclusively, generating various highly colored base-stabilized boriranes with an H-atom on the three-membered ring. These species thermally isomerize to 4bH-azaborepins via direct H-atom transfer from boracycle to pyridine with concomitant ring expansion. Furthermore, appropriate functionalization with mesityl/heterocycle substituents (thienyl, furyl and derivatives) enables quantitative phototransformations yielding rare, chiral N,B,X-embedded heterocycles (e.g. base-stabilized 1,2-thiaborinines and 1,2-oxaborinines), which display strong blue-green to orange-red emission in the solid state. Mechanistic insights on these highly regioselective transformations were obtained via kinetic data and computational investigations on their excited-states. The effect of charge-transfer character on the photoreactivity of this class of photochromic molecules was also investigated by substituting the aryl groups of N,C-chelate organoborates with varying amine-donors. These compounds possess bright and tunable charge-transfer luminescence depending on the donor strength of the amine functionality, as well as donor-dependent photochromic switching. These new findings help elucidate the influence of electronic structure on the photoreactivity of N,C-chelate organoborates. Lastly, combining a three-coordinated boron (BMes2) moiety with a four-coordinated photochromic organoboron unit leads to a series of new diboron compounds that undergo four-state reversible color switching in response to stimuli of light, heat, and fluoride ions.

abstract: PhD


title: From Surface Events in DEAP-3600 to the Radial Acceleration Relation in Spiral Galaxies

contributor: Physics, Engineering Physics and Astronomy

subject:
Astrophysics
Astroparticle Physics
Machine Learning
Galaxies
Dark Matter Detection

abstract: One of the most outstanding mysteries in the Universe is the nature of dark matter. In this thesis, two unique projects that focus on understanding dark matter are presented. First, Machine Learning is used to detect background signals in the DEAP-3600 direct detection dark matter experiment. Machine Learning algorithms are found to achieve a near order of magnitude improvement on discrimination of surface backgrounds ove a standard position reconstruction algorithm. To ward against over-fitting, the algorithms are fit to real data before being tested on simulated data. Validation is done by modifying the detector simulation and recording the change in performance. It is found that the Machine Learning algorithms are robust to small changes in the optics of the detector and so would be stable for use on the real data. The second project is a study of the intrinsic scatter of a scaling relation and its potential tension with the dark matter hypothesis. The Radial Acceleration Relation (RAR) relates the observed radial acceleration in a galaxy to that expected from a purely baryonic mass distribution. Lelli et al. (2017) have suggested that the RAR may have zero intrinsic scatter. If true, this would be inconsistent with the Λ Cold Dark Matter (ΛCDM) paradigm, but a natural prediction of Modified Newtonian Dynamics (MOND). A large sample of galaxies is collated from six independent samples, representing over an order of magnitude increase in the amount of data available to examine this scaling relation. To test the zero scatter hypothesis, a Monte-Carlo simulation with a zero intrinsic scatter assumption is constructed; observational uncertainties are then re-introduced to the data. This technique shows observational uncertainties are too small to account for the observed scatter in the relation. It is found that the RAR is consistent with standard ΛCDM models and that it has an intrinsic scatter of order 0.13 dex (∼ 50 % of observed). Further tests show that these results cannot be explained with non-circular motions or correlations with other galaxy parameters.

abstract: M.Sc.


title: The two-variable Artin conjecture and elliptic analogues

contributor:
Murty, M. Ram
Mathematics and Statistics

subject:
Artin's conjecture
Binary recurrence sequences
Primitive roots
Wieferich primes

abstract: In 1927, Emil Artin conjectured that for any integer a other than -1 or squares, the set of primes p for which a is a primitive root modulo p has positive density in the set of all primes. This was proven subject to the generalized Riemann hypothesis (GRH) by Hooley in 1967. In 2002, P. Moree and P. Stevenhagen formulated an analogous two-variable conjecture, and used a result of Stephens on binary recurrence sequences to prove the conjecture conditionally on GRH. In this thesis, we show unconditional lower bounds for this two-variable conjecture. In particular, we obtain a result about general binary recurrence sequences that can be applied to this problem. We also formulate an analogue of the two-variable conjecture in the context of elliptic curves, and prove an unconditional lower bound for elliptic curves of rank 1. Finally, we obtain some results about the largest prime factor of the nth cyclotomic polynomial evaluated at a fixed integer, and where we let n vary.

abstract: PhD


title: Reinforcement Learning for Decentralized Stochastic Control

contributor:
Yuksel, Serdar
Mathematics and Statistics

subject:
reinforcement learning
decentralized control
learning in games

abstract: We consider decentralized optimization of a controlled stochastic system where a  finite number of decision makers seek to arrive at optimal policies using only local measurements and cost realizations. For such a context, a recent result in the literature established convergence to person-by-person-optimal policies (and a class of Nash equilibrium policies in the game theoretic setup). Our main theorem is a convergence result to global optimality in a team-theoretic setup, and not only person-by-person optimality, with arbitrarily high probability.

abstract: M.Sc.


title: Exploring How Video-informed Feedback Supports Embedded Educator Professional Learning Between Middle Leader Facilitators and Teachers

contributor:
Klinger, Don A.
Education

subject:
educator professional learning
middle leader facilitators
teachers
feedback
classroom video

abstract:
The purpose of this study was to explore how video-informed feedback supported embedded educator professional learning (EPL) between middle leader (ML) facilitators and teachers, addressing gaps in EPL literature pertaining to the role of feedback and video in embedded, ML-facilitated EPL. Two research questions guided my study: How does a video-informed feedback model support embedded EPL between ML facilitators and teachers? and How do video-informed feedback dialogues between ML facilitators and teachers evolve to support EPL over time?
An embedded multiple case study design was used to study video-informed feedback between ML facilitators and teachers over one academic year in the context of a regional, math-based EPL initiative. A total of seven educators participated in this study: two ML facilitators and five teachers from two rural district school boards. Each facilitator represented a case; embedded units consisted of facilitator-teacher pairs. Primary data sources included semi-structured individual and dyadic interviews with participants and audio recordings of ML facilitator-teacher pairs’ feedback dialogues.
Data were analyzed using inductive descriptive and deductive provisional coding techniques to develop within case themes. Within case themes were further analyzed to develop four cross-case assertions in response to how video-informed feedback supported embedded EPL between ML facilitators and teachers. Cross-case assertions pertained to interrelated learning goals, video-informed feedback dialogues, responsive collaboration, and video-informed praise.
Key contributions of this research include my conceptual feedback model of embedded, ML-facilitated EPL as well as the importance of: (a) more knowledgeable-other support of both ML facilitators’ and teachers’ learning and practices—especially their data literacy; (b) setting and working toward interrelated goals for teachers and students to enhance EPL outcomes; (c) explicitly leveraging multi-source feedback models that incorporate diverse classroom data, including video, to help ML facilitators and teachers co-construct practice-based evidence to inform EPL; and (d) video-informed praise from ML facilitators to teachers which enables ML facilitators’ subsequent coaching feedback and teachers’ self-regulation. More broadly, this study highlights the importance of trusting professional relationships coupled with a focus on diverse sources of practice-based evidence to enable meaningful, constructive dialogues in the context of embedded, ML-facilitated EPL and to support desired outcomes for educators and students.

abstract: PhD


title: Measurement of Cosmogenic Production Rates in Ge with CDMSlite

subject:
dark matter
physics
cosmogenics
production rates
supercdms

abstract:
The majority of matter in the Universe is non-luminous, non-baryonic, and as of yet undiscovered. The SuperCDMS experiment searches for this "dark matter" in the form of Weakly Interacting Massive Particles (WIMPs), operating semiconducting detectors at cryogenic temperatures to measure energy deposits from dark matter interactions. These efforts have resulted in world leading limits on the interactions of dark matter with ordinary matter.  The next phase of SuperCDMS is under construction at SNOLAB near Sudbury, ON.

Interaction of cosmic rays with detector material can result in the production of radioactive isotopes, the decay of which results in background in the measured energy spectrum. Tritium is expected to be the limiting background for SuperCDMS SNOLAB. Production rates of tritium and other cosmogenic isotopes are not well known, with a wide spread in theoretical calculated rates and only a single measurement previously published for tritium. The work in this thesis details the measurement of cosmogenic production rates using low energy spectra measured by SuperCDMS.

abstract: M.Sc.


title: Stress-Related Effects of Phoenixin on Nucleus of the Solitary Tract Neurons

contributor:
Ferguson, Alastair
Neuroscience Studies

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Stress
Electrophysiology
Phoenixin
Nucleus of the Solitary Tract

abstract: Phoenixin (PNX) is a recently discovered neuropeptide that was initially determined to positively contribute to reproductive functioning. Since its discovery, however, PNX has been implicated in a diverse range of physiological activity, including anxiety-like behavior, nociception, memory retention, and food intake. With a robust pattern of expression to compliment these physiological actions, it is clear that PNX plays a pleiotropic role. The nucleus of the solitary tract (NTS), a critical autonomic integrating center in the hindbrain, is one of the many areas with dense expression of both PNX and its receptor, GPR173. Using both extracellular and whole-cell current clamp recording techniques in a coronal NTS slice preparation, this study characterized the effects of PNX on both spike frequency and membrane potential of NTS neurons in order to determine neuronal effects of the peptide. Extracellular recordings demonstrated that PNX increased firing frequency in 32% of male rat NTS neurons, and patch clamp recordings indicated that this effect also existed for membrane potential, with 50% of NTS neurons depolarizing in response to application of the peptide. Our study took an abrupt turn when total responsiveness to PNX in NTS neurons declined suddenly to 9%. This effect was subsequently attributed to construction in our laboratory facility after rats were relocated to a construction-free facility and PNX responsiveness was recovered. Rats were then placed on a corticosterone (CORT)-stressor treatment that replicated the decreased PNX responsiveness within 2 weeks and had no effect on the responsiveness of neurons to another neuropeptide, Angiotensin II (ANG). These results implicate PNX in the central integration of stress and potentially provide new insight into a factor of stress-related infertility.

abstract: M.Sc.


title: Evaluating the pre-B-cell receptor as a potential mediator of leukemogenesis downstream of the TCF3-PBX1 oncogenic transcription factor

contributor:
LeBrun, David
Pathology and Molecular Medicine

subject:
TCF3-PBX1
pre-B cell receptor signaling
Acute lymphoblastic leukemia

abstract: Approximately 5% of B-progenitor acute lymphoblastic leukemia (B-ALL) harbor a somatic 1;19 chromosomal translocation which generates a fusion gene coding for TCF3-PBX1. Recent studies have shown that leukemic progenitors with t(1;19) occur in a distinct subset of B-ALL cases that often express a functional pre-B-cell receptor (pre-BCR). It is hypothesized that TCF3-PBX1 drives the leukemogenesis of these cells by promoting aberrant pre-BCR signaling through transcriptional activation of genes encoding pre-BCR components (IGHM, CD79A, CD79B, IGLL1, VPREB1 and VPREB3). To test this hypothesis, we have established short hairpin RNA (shRNA) knockdown models in two different t(1;19) B-ALL cell lines (RCH-ACV and 697). Expression of the knockdown shRNA against the TCF3-PBX1 transcript considerably reduced cell culture-initiation and proliferation. We then performed RNA-Seq in both of our knockdown models and determined that TCF3-PBX1 knockdown surprisingly activates, rather than represses, the expression of IGHM, CD79A, CD79B, IGLL1, VPREB1 and VPREB3. Despite this, we observed a marked reduction in phosphorylation and activation of AKT and ERK in ¬TCF3-PBX1-silenced cells. Additionally, TCF3-PBX1 knockdown had no effect on SYK phosphorylation.  Altogether, our results suggest that TCF3-PBX1 promotes t(1;19) B-ALL proliferation by activating PI3K/AKT and MAPK/ERK signaling in a pre-BCR independent manner. In considering alternative mechanisms by which TCF3-PBX1 promotes cell proliferation, TCF3-PBX1 activates the expression of genes encoding key downstream pre-BCR signaling molecules such as the Src-family kinase BLK and the atypical protein kinase C PKCζ either of which could promote pro-survival signaling pathways. Alternatively, we propose that TCF3-PBX1 promotes Notch or Rho signaling and that these pathways might crosstalk with the pre-BCR.

abstract: M.Sc.


title: Does Menstrual Cycle Phase Impact the Brachial Artery Flow Mediated Dilation Response to Acute Hyperglycemia?

contributor:
Pyke, Kyra
Kinesiology and Health Studies

subject:
Endothelial Function
Estrogen
Vascular Function
FMD
Glucose Regulation

abstract: Acute hyperglycemia transiently impairs endothelial function in healthy males when assessed via flow-mediated dilation (FMD). However, research in female participants is lacking and the impact of menstrual phase (early follicular (EF) and late follicular (LF)) on vulnerability to acute hyperglycemia-induced endothelial dysfunction is unknown. It is hypothesized that hyperglycemia-induced endothelial dysfunction will be attenuated in the LF phase. Seventeen healthy, naturally menstruating women (21 ± 1 years [mean ± SD]) participated in three experimental visits. During two visits (one EF phase, one LF phase), endothelial function was assessed via brachial artery FMD before and 60-, 90-, and 120-min after an oral glucose challenge (75g glucose/300mL solution). Blood samples were taken to assess blood glucose, insulin, estradiol, progesterone and viscosity. During a third visit in the EF phase, participants ingested 300mL of water as a time-control for FMD. Blood samples were only taken for blood glucose and viscosity during this visit. Additionally, ovulation testing was used to confirm the LF phase. Data are [mean ± SD]. Glucose and insulin levels increased 30min post-glucose ingestion, with no difference between visits (p < 0.001). FMD was reduced 90min post-glucose ingestion (Post90) during the EF glucose visit (Pre: 8.7 ± 2.9%, Post90: 6.2 ± 2.8%, p = 0.001; Cohen’s d = 0.864). FMD-impairment during LFGlucose was not significant (Pre: 8.4 ± 2.4%, Post120: 6.8 ± 2.7, p = 0.089; d = 0.649). A direct comparison of EF and LFGlucose delta-FMD did not reach significance (p=0.117) revealing a small effect of phase (d = 0.431) on vulnerability to hyperglycemia-induced FMD impairment. These results suggest that the cyclic elevation in estrogen that occurs during the menstrual cycle confers a small degree of protection from acute hyperglycemia-induced impairment in endothelial function. In order to fully characterize the impact of acute stimuli on vascular function in premenopausal women, it is essential to examine responses across multiple phases of the menstrual cycle.

abstract: M.Sc.


title: The Emergence and Consequences of Voice Climate

contributor:
Raver, Jana
Business

subject:
Voice Climate
Voice

abstract:
The objective of this thesis was to further the nascent paradigm on team-level voice, specifically voice climate and team voice. First, in Study 1, I examined how and why voice climate emerges in teams. In particular, I proposed that leaders stimulate shared perceptions of voice climate depending on how they previously responded to voice (i.e., voice acceptance or rejection). In turn, I proposed that voice climate enhances teams’ subsequent voice, as mediated by team risk, fear, efficacy, and vitality. I tested these propositions with a between-subjects team experiment, in which I manipulated a confederate leader’s responses to their team’s voice, and assessed its effects on team affect, cognitions, and subsequent voice.
Next, in Study 2, I conducted a multi-wave training experiment to explore whether we can train leaders to successfully encourage their teams to speak up. First, I developed a one-hour training program that focussed on leader openness and responsiveness to voice, based on insights from the voice and leadership training literatures. Next, I randomly divided 65 students into either a 1-hour voice or control condition, and administered the training. Finally, approximately one week later, these students participated in a 1-hour team task, after which their team members rated leaders’ openness and responsiveness to voice, as well as voice climate and team voice.
Finally, in Study 3, I investigated whether, how, and why voice climate ultimately affects team functioning by focussing on the mediating mechanisms that link voice climate to team learning and performance. In particular, I proposed that voice climate enhances team effectiveness through its sequential effect on negative and positive team affect (i.e., fear and vitality), cognitions (i.e., risk and efficacy), and voice (i.e., quantity and quality). I assessed these propositions with multi-sourced field surveys with 59 teams from 8 Canadian companies.

abstract: PhD


title: Change in a person's cognitive/emotional state, including expecting pain, is linked to connectivity change in identified brainstem and spinal cord networks

contributor:
Stroman, Patrick
Neuroscience Studies

subject:
brainstem
spinal cord
fMRI
resting-state
pain
networks

abstract:
Resting-state functional MRI examines activity of the central nervous system in the absence of a specific task or stimulus, and has been used to investigate coordinated activity within the cerebral hemispheres, as well as the brainstem and spinal cord. While previous research has shown coordinated resting-state BOLD fluctuations in the brainstem and cord, the extent of resting-state networks (RSNs) and their function are still unclear. Characterizing these networks is an important step towards understanding the complex processing that occurs in the spinal cord and brainstem outside of a reaction to a stimulus.
The overall aim of this thesis was to investigate the function of spinal cord and brainstem RSNs, by examining how these networks change when participants are experiencing different cognitive states. If a person’s cognitive/emotional state can be shown to influence resting-state BOLD signal fluctuations in the brainstem/cord, then we can infer that a function of these RSNs is to modulate the excitability of spinal cord neurons. We first aimed to confirm the presence of RSNs in the brainstem and spinal cord. After doing so, we present evidence that, while RSNs are largely consistent across 3 conditions (a resting-state condition, an audio presentation, and a video), watching a video or listening to an audio presentation alters these networks in specific ways. Combined with prior evidence, these results show that the observed networks likely help integrate homeostatic autonomic functions.
Building on this evidence, we investigated how connectivity in the previously-identified networks is altered when a participant is specifically expecting pain. We provide evidence that coordinated brainstem and spinal cord networks are affected by the expectation of pain differently than by other distracting situations such as focusing on a video. We conclude that these networks may serve to integrate autonomic regulatory functions with pain processing. Linking the function of these networks to homeostatic autonomic control and pain modulation is an important step in understanding the complex brainstem/spinal cord activity that occurs aside from a reaction to a painful stimulus. Findings of this thesis will help provide a deeper understanding of pain modulation and subjective experiences of pain, such as placebo/nocebo effects.

abstract: M.Sc.


title: Deformable Link Segment Model for Analysis of Prosthetic Foot-ankle Components

contributor:
Li, Qingguo
Bryant, John Timothy
Mechanical and Materials Engineering

subject: Biomechanics Prosthetics Gait Energy Deformation

abstract:
Recent literature suggests that passive prosthetic foot-ankle devices, when optimized, may provide similar energy performance as the natural foot, but this has yet to be realized with current designs. Of concern is the inconsistency between biomechanical and structural measures of device performance. Biomechanical studies of energy performance rely on estimating power based on the deformation velocity. However, a consensus has yet to be reached regarding its definition and interpretation, due, in part, to a lack of clarity regarding the nature of deformation in these devices. Specifically, a majority of analyses use rigid body assumptions to estimate the angular velocity of these deformable systems.

An extension of current methods is developed, termed the Deformable Link Segment (DLS) model, in which the deformation velocity is estimated using a series of instantaneous equivalent linkages. The novelty of the approach is that an estimate of the angular velocity is not required and the deformation velocity can be calculated without rigid body assumptions. Practical application of the DLS model is demonstrated for biomechanical analyses with a small cohort of prosthesis users. DLS deformation velocity and deformation power of prosthetic foot-ankle devices are calculated and results are compared to current methods in the literature. These models are distinguished by the reference points and segment angular velocity. Comparison indicates that the DLS model produces results that are distinct, yet similar in general trend to estimates in the literature.

A mechanical testing method to characterize prosthetic foot deformation is developed based on a simplification of the DLS model. Structural properties are measured from a series of force-deflection curves at specific loads and shank angles. Five prosthetic feet with differing designs and structural properties are analysed to provide the predicted vertical deflection throughout simulated stance. A method is proposed to estimate foot-ankle deformation velocity from these measures.

The framework established will further enable researchers in the design and optimization of the energy performance of prosthetic foot-ankle devices and inform clinicians in the selection of patient-specific prosthetic systems.

abstract: PhD


title: A machine learning application for form-finding of tensegrity structures

contributor:
Blostein, Dorothea
Computing

subject:
Computer Science
Computing
Form-Finding
Tensegrity
Genetic Algorithm
Machine Learning
Fitness Function

abstract:
Tensegrity (tensional integrity) is a structural principle where rigid elements (struts) under compression are held together by a network of elastic elements (cables) under tension. Tensegrity structures have many applications in modelling the natural world. Tensegrity research has been applied to fields including robotics, art, architecture, and biology. In recent years, computer simulation has been introduced as a tool to allow researchers to design, build, and simulate tensegrity structures. Structures designed both as physical models and in simulation software can require several iterations of fine adjustments.

In this thesis, we develop a form-finding application to reduce the iterative adjustments required when designing a tensegrity structure. Form-finding is the process of finding a structural configuration capable of a state of self-stressed equilibrium – when tension and compression stabilize the structure. Our form-finding application uses a tensegrity structure that is not necessarily in an equilibrium state represented as a graph as input, and produces either (a) failure when no equilibrium state is possible, or (b) a fully attributed labeled graph of a tensegrity structure in an equilibrium state. In this thesis, we use an efficient fitness function and genetic algorithms to find the stable state of a tensegrity structure. Through our form-finding application, we aim to promote the use of computer simulation, and collaboration between tensegrity researchers.

abstract: M.Sc.


title: Examining the Role of Biopsychosocial Factors in Disability Among Individuals with Inflammatory Bowel Disease

contributor:
Tripp, Dean
Psychology

subject:
inflammatory bowel disease
disability
depression
pain catastrophizing
social support
pain

abstract: IBD is an inflammatory disease that affects the gastrointestinal tract, encompassing two conditions (Crohn’s disease and ulcerative colitis). IBD negatively affects patients in a physical and psychosocial manner, which significantly impacts their quality of life. Related to quality of life is disability, which is an under-researched topic in the IBD literature. Models theorize that disability is the result of a disease and its related impairments, limitations, and restrictions it causes to an individual and their life. Environmental and psychosocial factors are also theorized to affect this process of disablement. Biopsychosocial factors such pain, depression, pain catastrophizing, and social support have all been linked to IBD disability-related outcomes, but no multivariate research has examined all of these factors simultaneously. This study aimed to elucidate the role of psychosocial factors in the process of disablement in an outpatient tertiary care IBD sample. Depressive symptoms, pain catastrophizing, and perceived social support were examined as mediators in the relationship between pain and pain-related disability cross-sectionally and longitudinally. Alternate models exploring feedback effects amongst disability and pain, and potential moderators (gender, disease type) of the mediation relationships were also tested. Cross-sectionally, depressive symptoms and pain catastrophizing, but not perceived social support, were significant mediators in the relationship between pain and pain-related disability. Support was found for feedback effects, such that disability predicted pain both cross-sectionally (through depressive symptoms as a mediator) and longitudinally (directly). These findings augment the research supporting a biopsychosocial model of IBD disability. Further, these results highlight the importance of targeting psychological factors such as depressive symptoms and pain catastrophizing in the treatment of individuals with IBD.

abstract: M.Sc.


title: Novel cytokines in innate immunity: IL-27 and IL-30 enhance responsiveness to gram-negative bacterial components in human myeloid cells

contributor:
Gee, Katrina
Biomedical and Molecular Sciences

subject:
Interleukin-27
Lipopolysaccharide
Innate immunity
Myeloid cells
Gram-negative bacteria
Interleukin-30

abstract: In response to microbial stimuli, innate myeloid cells are potent producers of cytokines that function to mediate inflammation. This thesis investigates two related cytokines, IL-27 and IL-30, to identify novel proinflammatory mechanisms to improve treatments for bacterial infections. IL-27 is comprised of IL-27p28 and EBI3 subunits; the IL-27p28 subunit, also named IL-30, can also signal independently of EBI3. To date, most studies on IL-27 have focused on its role in CD4+ T cell differentiation. IL-30 has been recognized as an antagonist of IL-6, IL-11, and IL-27 in CD4+ T cells. In primary monocytes, IL-27 promotes proinflammatory cytokine production and TLR4 expression in monocytes for a potent inflammatory response to bacterial endotoxin, LPS. Barring these studies, functions of IL-27 and IL-30 in human myeloid cells have not been well described, and therefore are the focus of this thesis. Specifically, this thesis compares IL-27 and IL-30 signaling in human monocytes and explores novel proinflammatory effects of IL-27 and IL-30 on cytokine production in response to either Gram-negative bacteria or bacterial components in myeloid cells. The effects of IL-27 are explored in Salmonella enterica infection, NLRP3 inflammasome activation, and induction of endotoxin (LPS) tolerance in human monocytes and macrophages, while the effects of IL-30 are defined in human monocytes. IL-27 and IL-30 induce IP-10 production in human monocytes in a STAT-dependent manner. Furthermore, pre-treatment with IL-6 interferes with IL-27 and IL-30 functions in human monocytes. Similarly to TLR4, IL-27 treatment also enhances TLR5 expression in human monocytes and macrophages, inducing cytokine production in response to TLR agonists LPS and flagellin or S. enterica infection. IL-27 also increases LPS/ATP-mediated NLRP3 inflammasome activation and IL-1β production in human monocytes via upregulated TLR4 and P2X7 expression. Comparing human THP-1 monocytes and PMA-differentiated THP-1 macrophages, CD14 expression plays a role in LPS and IL-27 responsiveness, whereby IL-27-mediated inhibition of LPS tolerance is greater in CD14low THP-1 monocytes compared to CD14high PMA-differentiated THP-1 macrophages. Overall, this thesis demonstrates novel proinflammatory roles for IL-27 and its subunit IL-30 in innate immune responses and may serve as novel adjuvant candidates for vaccine design against Gram-negative bacterial infections.

abstract: PhD


title: Delineating Novel Genetic and MicroRNA Regulatory Mechanisms in Aggressive Subtypes of Breast Cancer

contributor:
Nicol, Christopher
Pathology and Molecular Medicine

subject: Peroxisome Proliferator Activated Receptor Gamma

subject: HER2+ Breast Cancer

subject: Triple Negative Breast Cancer

subject: MicroRNA

subject: Knockout Mouse Models

subject: Rosiglitazone

subject: Next Generation Sequencing

subject: Machine Learning

subject: PPARgamma

subject: Breast Cancer

abstract: Breast cancer will be diagnosed in over 26,500 Canadians this year. Despite advances, identifying who will develop aggressive breast tumours or who will respond to treatment remains a clinical challenge. This dissertation aimed to delineate novel genetic and microRNA (miRNA) regulatory mechanisms that may contribute to metastases and poor clinical outcomes among patients with aggressive subtypes of breast cancer; those overexpressing human epidermal growth factor receptor 2 (HER2+) and triple negative breast cancer (TNBC). The first component of my thesis focuses on the study of miRNAs, small non-coding RNA molecules that negatively regulate gene expression at the post-transcriptional level to function as both oncogenes and tumour suppressors in breast cancer. We used next generation sequencing to define miRNA expression profiles that correlate with clinical outcomes among a local TNBC patient cohort. My data unveiled new prognostic and predictive miRNA biomarkers significantly correlated with improved overall, relapse-free survival and treatment response among TNBC patients. The second component of my thesis focuses on the study of peroxisome proliferatoractivated receptor (PPAR)g, a transcription factor that controls the expression of genes essential for normal metabolism of fats and sugars in the body. This study used unique in vitro and in vivo models to assess the effects of targeted PPARg deletion in the same HER2+ transformed mammary epithelial cells that drive breast tumour progression. My data are the first to suggest PPARg loss enhances the initiation but not the progression of HER2+ breast cancer, while PPARg ligand treatment decreases these effects. Together, my research elucidates new signaling pathways and therapeutic strategies that may reduce deaths and improve clinical outcomes for HER2+ and TNBC patients.

abstract: PhD


title: Going With The Flow: Selective phosphodiesterase 4D7 (PDE4D7) regulation of vascular endothelial cell responses to fluid shear stress

contributor:
Maurice, Donald
Biomedical and Molecular Sciences

subject:
endothelial
cardiovascular
signalling
heart disease
fluid shear stress

abstract: Vascular endothelial cells (VECs) regulate their phenotype in response to the frictional force exerted by the flowing blood, fluid shear stress (FSS). The hemodynamics dictating this force determine, to a large extent, the likelihood that a given region of a blood vessel will develop atherosclerotic plaque. In linear arterial segments, VECs are exposed to high laminar unidirectional FSS (15-20 dyne/cm2), whereas in bifurcations, arches and branch points, VECs encounter low magnitude/oscillating or otherwise disturbed FSS (0-4 dyne/cm2). High laminar FSS promotes establishment of an adaptive VEC phenotype, characterized by the expression of anti-thrombotic, anti-inflammatory and anti- atherogenic genes. Conversely, low and oscillating flow causes VECs to express pro-inflammatory, pro-thrombotic genes and adopt an athero-prone phenotype. Previous studies have identified mechanosensory signalling molecules that allow VECs to sense and respond to FSS, which include vascular endothelial cadherin (VE-cadherin), platelet endothelial cell adhesion molecule 1 (PECAM- 1) and vascular endothelial growth factor receptor 2 (VEGFR2). Research conducted by our group has previously shown that exchange protein activated by cAMP (EPAC1) and cyclic nucleotide phosphodiesterase 4D (PDE4D) populate a multi-protein signalling complex along with VE- cadherin. These proteins function together to regulate VEC barrier function, cell morphology and gene expression of in response to FSS. Now, we have investigated this compartmentalized signalling complex in greater detail, and have identified that one splice variant, namely phosphodiesterase 4D7 (PDE4D7), controls VEC gene regulation in response to FSS, while another, PDE4D5, does not. Indeed, we show that PDE4D7 silencing with siRNA attenuates the upregulation of krüppel-like factor 2 (KLF2), endothelial nitric oxide synthase (eNOS) and thrombomodulin (TM) in VECs exposed to FSS. This work identifies a potential novel specific therapeutic target for the treatment or prevention of atherosclerosis and improves our understanding of mechanosensory signal transduction in the vascular endothelium.

abstract: M.Sc.


title: Coupling the Mass Transport Mechanisms of the Porous Transport Layer and Flow Channel of a Proton Exchange Membrane Fuel Cell

contributor:
Pharoah, Jon
Mechanical and Materials Engineering

subject:
Fuel Cell
PEMFC
CFD
Porous Transport Layer
Water Transport
Proton Exchange Membrane Fuel Cell
Channel
Computational Fluid Dynamics
OpenFOAM
Mass Transport
Pore Network Model
Volume Of Fluid Method

abstract: A coupled model was created that linked the mass transport mechanisms of the channel and the Porous Transport Layer of a Proton Exchange Membrane Fuel Cell. A Volume of Fluid solver in the open-source Computational Fluid Dynamics software, openFOAM, was used to model the two-phase flow in the channel. A Pore Network Model designed for Proton Exchange Membrane Fuel Cells and found in literature was implemented into openFOAM to model the two-phase flow in the Porous Transport Layer. The Pore Network Model was recast into a form suitable for the Finite Volume Method used in openFOAM allowing for coupling between these two components. A coupling strategy called Dirichlet-Neumann partitioning was used for pressure on the boundary that separates the two domains. A Neumann boundary condition for pressure was applied in the channel and a Dirichlet boundary condition for pressure was applied in the Pore Network Model. The value of pressure was passed from the channel to the Pore Network iteratively until convergence was achieved. It was determined that the air pressure in the Porous Transport Layer remains constant before breakthrough therefore allowing for the Pore Network Model only to be solved before breakthrough using a linear pressure distribution along the channel boundary to capture the convective effects of the channel. The effects of convection on water transport in the Porous Transport Layer was investigated and the convective effects were significant enough to cause mass conservation violations when the air inlet velocity was altered from 5-10 m/s. It was determined that the domain widths often used in literature are too small to conserve mass and near wall effects permeate towards the domains center. Two common Porous Transport Layer materials were recreated and it was determined that within the expected range of pressure gradients significant movement of water downstream was observed for the SGL10BA material with less significant movement for the Toray090 sample. It was determined that for post-breakthrough simulations water is needed in the channel to properly set the injection velocity. The numerical stability of these post-breakthrough simulations proved to be extremely fragile.

abstract: M.A.Sc.


title: Teaching Elementary-aged Children on the Autism Spectrum:  the Key Issues, Challenges and Successes Described by Specialist Teachers

contributor:
Colgan, Lynda
Education

subject:
autism
inclusion
specialist teachers

abstract:
The most recent prevalence rates from the Public Health Agency of Canada’s National ASD Surveillance System (NASS) (PHAC, 2018) indicate that 1 in 66 children and youth (i.e., 15.2 per 1000) 5-17 years of age were diagnosed with ASD in 2015 across seven provinces and territories. The Ontario Ministry of Children and Youth Services (MCYS) states that there are an estimated 40,000 children and youth with ASD in the province (“Newsroom: Ontario Providing More Supports for Children with Autism,” 2016). Specifically, in the context of Ontario’s education system, and in light of the current study, there is a rapid increase of students with exceptionalities no longer being isolated to special education classrooms, as a result, general education teachers are increasingly teaching the autism spectrum disorder (ASD) student population (Wilczynski et al., 2011). A large number of studies determine that general education teachers do not support an inclusive model of teaching as they lack adequate training in teaching inclusively, as well, they voice concerns about their lack of confidence, feelings of low self-efficacy, and have expressed a shortage of continuing education opportunities (Finke, McNaughton & Drager, 2009; Lindsay et al., 2013; McCray & McHatton, 2011; Ross-Hill, 2009; Scruggs et al., 2007). This study aimed to fill in the gap by exploring the experiences of specialist teachers who have worked more extensively with students with ASD.
Specifically, this qualitative descriptive study describes effective strategies used by four specialist teachers that support the inclusion of students with ASD. In talking to specialist teachers about effective strategies they use, I hoped to gain an in-depth understanding of their attitudes and beliefs towards including students with ASD, and learn how teachers create a safe and accepting environment within their classrooms through the use of different tools, resources and practices.
The findings of this study suggest that it is important that educators who work with students with ASD be highly committed; in that, they are driven to find resources and tools, willing to adapt their classroom routine/instruction, and demonstrate resiliency when faced with challenges. Furthermore, the specialist teachers stressed the importance of tailoring instruction to suit the individualized functional needs of students, as opposed to a sole focus on curriculum and diagnosis. This study also suggests that a structured but flexible learning environment is fundamental to teaching inclusively (i.e., teaching content using multiple modes and in different settings based on student needs). Most importantly, this study provides an overview of a number of strategies deemed successful in supporting the inclusion of students with autism spectrum disorder and provides detailed descriptions and explanations of how and why each strategy is used in practice. This study provides useful information for individuals at all levels of education, from government policy makers to front-line teachers by making classroom-validated resources, practices and affective factors transparent and scalable.

abstract: M.Ed.


title: ¡Somos La Puya! (We Are La Puya!): Community Resistance to Canadian Mining Company Operations in Guatemala

contributor:
Lovell, W. George
Nolin, Catherine
Geography and Planning

subject:
Violence
Geographies of development
Postcolonialism
Resource extraction
Rights defenders
Guatemala
Canada
Feminist methodology
Activist methodology

abstract:
This dissertation contributes to literatures of postcolonial and critical geographies of development by documenting a landscape of violence that shapes processes of how people make place at the local level in response to extractive resource development in Guatemala. Three case studies of the Fénix, Marlin, and El Escobal mines offer context when situating the fourth and lesser known El Tambor mine. Transnational mining companies and the Guatemalan government are intent on exploiting natural resources in order to fuel economic development. In response, residents of the municipalities of San José del Golfo and San Pedro Ayampuc joined together to form La Puya, a community situated at the entrance of the Canadian, and later American-owned and operated El Tambor mine.
Using feminist and activist methodologies as a framework to guide fieldwork in Guatemala and Canada, the dissertation focuses on the voices of community members from La Puya as a means to challenge mainstream ideas about mining as an appropriate method of development. Interviews conducted in the summers of 2012 and 2013 asked community members about their experiences opposing the operations of transnational mining companies and the policies and actions of the Guatemalan government. Engaging a critical geographic approach, analyses found that individuals who take up opposition to neoliberal development face daily forms of direct and indirect violence that negatively impact their lives and communities. Additionally, the dissertation explores the foundations of structural violence created in Canada through on site observations in 2016 and 2017 at the annual conference of the Prospectors and Developers Association of Canada (PDAC), an Access to Information (ATI) request, and public letters and press releases from transnational mining companies operating in Guatemala. Absent from these latter fora are the experience of violence that affect the lives of those living with problematical development. Therefore, the aim of this dissertation is to amplify the voices of La Puya in direct opposition to the actions of foreign companies and government officials who dominate discussions of development.
The dissertation concludes that disputes between transnational companies, local communities, and the Guatemalan government derive from lack of meaningful consultation, failure by the state to protect the rights of Indigenous and non-Indigenous populations, and environmental degradation as a result of extractive operations.

abstract: PhD


title: The regions connecting the membrane spanning and nucleotide binding domains of MRP1 are functionally distinct

contributor:
Cole, Susan P. C.
Pathology and Molecular Medicine

subject: Multidrug Resistance Protein 1, structure function analysis, membrane protein expression, organic anion transporter, ABC transporter

abstract: Multidrug resistance protein 1 (MRP1) is a 190 kDa ATP-binding cassette transporter which effluxes xeno- and endobiotic organic anions including estradiol glucuronide (E217βG) and the pro-inflammatory leukotriene C4 (LTC4). MRP1 also confers multidrug resistance by reducing intracellular drug accumulation through active efflux. MRP1 has three membrane spanning domains (MSD), two of which form the solute translocation pathway, and two functionally asymmetric nucleotide binding domains (NBD) which bind and hydrolyze ATP. MSD1/2 are linked to NBD1/2 by connecting regions (CR) 1 (aa 600-642) and CR2 (aa 1249-1291), respectively. To test the hypothesis that the CRs are functionally distinct, eight CR residues (four in CR1: S612A, R615A, H622A, E624A and four in CR2: T1270A, P1275A, W1287A, G1291A), were targeted for Ala substitution based on sequence conservation and structural location of the residue, and their phenotypes investigated. Cellular levels of three of four CR1 mutants (S612A, R615A, E624A) were substantially lower than wild-type MRP1 (by 60%, 95%, 95%, respectively; p<0.05). Of the four CR2 mutants, only W1287A levels were markedly reduced (by 80%; p<0.05) and more conservatively substituted mutants (W1287F, W1287Y) remained <65% of wild-type MRP1levels (p<0.05). Analyses of apo bMrp1/MRP1 cryo-EM structures and models suggested that some of these mutation-sensitive residues might participate in stabilizing interactions. However, this idea was not supported by double exchange mutations which all failed to improve MRP1 levels. Immunofluorescence showed that while CR1-H622A localized to the plasma membrane like wild-type MRP1, the poorly expressing CR1 mutants (S612A, R615A, E624A) were retained intracellularly. In contrast, all four CR2 mutants, including the poorly expressing W1287A, localized exclusively to the plasma membrane. For CR mutants expressed at levels comparable to wild-type MRP1 (H622A, T1270A, P1275A, G1291A), only CR2-G1291A exhibited a substrate selective change in [3H]LTC4 transport (reduced by 40%; p<0.05) whereas [3H]E217βG and estrone sulphate transport were largely unaffected. Together these results support the hypothesis that CR1 and CR2 play important, but distinct, roles. CR1 may be more important for the plasma membrane expression of MRP1 whereas CR2 may play a larger role in transport activity. The mechanisms underlying these functional differences should be investigated further.

abstract: M.Sc.


title: Critical Femininities: The Development and Application of Femme Theory

contributor:
Burfoot, Annette
Sociology

subject:
Critical Femininities
Intersectionality
Femme Theory
Femme Identity
anti-femininity
discrimination
prejudice
sexual minorities
LGBTQ
aggression
femmephobia

abstract: Despite the accumulating evidence to warrant the deliberate consideration of femininity, there has been a continued neglect of femininity as an important intersectional axis. In addition, despite the numerous manifestations of oppression based in femininity (e.g. slut-shaming, sissyphobia, effemamania, femiphobia, misogynoir, trans-misogyny), there has yet to be an examination and application of how these systems relate and inform one another. This collection of articles argues that these sources of oppression are different symptoms of the same underlying social prejudice: the devaluation of femininity. Consequently, over the course of the three iterative chapters, I establish Femme Theory as a theoretical framework that requires bringing feminine multiplicities and feminine devaluation into focus within interdisciplinary and intersectional research. In so doing, this dissertation proposes and facilitates the growth of Critical Femininities as an emergent field of inquiry in which feminine intersections are central to understanding the ebbs and flows of power, particularly in relation to social inequalities. This dissertation contributes to the growth of a field of Critical Femininities through the development of Femme Theory, its subsequent illumination and refinement using a qualitative approach, to finally applying Femme Theory using quantitative methodologies. Consequently, this dissertation develops a theoretical framework that makes central the roles of femininity and femmephobia in making sense of social realities, while highlighting the importance of an intersectional approach that not only includes race, gender, class, and sexuality, but also gender expression and, more specifically, femininity.

abstract: PhD


title: Towards Carbon Free Energy Systems in Canada: Case Studies in the Ontario Transportation and Canadian Energy Export Sectors

subject:
Battery Electric Vehciles
Fuel Cell Electric Vehicles
Electricity Demand
Transportation
Energy Exports

abstract: With climate change being arguably the most important problem of this century, solutions must be researched, developed and implemented across the globe. Canada has shown progress over time in the electricity sector to implement renewable energy sources and limit the impact of climate change, however there is still substantial work to be done in both the transportation and energy export sectors. Research into each sector is conducted as two separate studies; one comparing the impact of battery electric vehicles and hydrogen fuel cell vehicles on the Ontario energy generation system, and the other showing the required renewable energy systems necessary to transition the Trans Mountain pipeline expansion to using hydrogen fuel instead of diluted bitumen. In the case of the first study, the electrical demand pro le in the province in any given season is able to be level when fuel cell vehicles and hydrogen generation are introduced. Conservatively only 3,000 MW of clean, base-load generation would have to be added in order to entirely eliminate the need for oil and gas in the province, and this required capacity becomes less as the e ciency of electrolysis improves over time. In the case of the second study, it is shown that with the large scale development of renewable energy systems (mostly wind generation), the need for oil and gas in the energy export sector can be transitioned to a cleaner alternative in hydrogen, whether it be the present-day exports to the United States of America or the future exports to the Asia-Pacific region by means of the new Trans Mountain pipeline expansion. In each case, overwhelmingly positive environmental and economic impacts are evident for specific provinces, and Canada as a whole.

abstract: M.A.Sc.


title: The Quenching of Cluster Galaxies

contributor: Physics, Engineering Physics and Astronomy

subject:
Galaxies
Galaxy clusters
Galaxy evolution
Quenching
Astronomy
Astrophysics

abstract:
In this thesis we present two projects investigating the evolution and quenching of cluster galaxy star formation (SF) activity. Leveraging a sample of 36 galaxy clusters, we measure the level of member SF activity. Over the 7.5 billion years spanned by our clusters, from z=1.5 to z=0.15, the SF activity of cluster galaxies decreases by a factor of 11. This is much larger than the three-fold decline experienced by star-forming galaxies (SFGs), or the factor of four drop for quiescent galaxies, which have SF activity more than an order of magnitude lower than SFGs. The overall evolution of cluster member SF activity is driven not by the decline of either subset, but instead by the transitioning of galaxies from star-forming to quiescence. Indeed, from z=1.5 to z=0.15, the fraction of quiescent galaxies rises from 28% to 88%.

To investigate the impact of strangulation, a long timescale quenching mechanism, we determine whether 58 members of the nearby galaxy cluster Abell 1795 possess hot halos. Markov chain Monte Carlo sampling is used to fit surface brightness profiles (SBPs) of stacked X-ray images with models that account for the dominant X-ray emission in and around cluster members. Hot gas halos around outer Abell 1795 members are detected, in a statistical sense. Inner cluster hot halos, however, remain undetected, with a luminosity upper limit six times lower than the hot halo luminosity in the outer cluster. This suggests that Abell 1795's intracluster medium is likely stripping the hot gas halos of infalling members.

To further test our modeling technique we apply it to five additional clusters. Combining their data, we generate profiles and retrieve a good fit to the inner cluster SBP. Due to a relative lack of data in the clusters' outskirts, we are unable to provide much constraint on hot halo presence. We propose stacking a greater number of outer cluster members, which would necessitate acquiring additional X-ray data, likely through a more targeted search of the Chandra Data Archive.

abstract: PhD