title: The Relationships Between Body Image, Leisure Time Physical Activity, And Composition Among People Living With Spinal Cord Injury

contributor:
Ginis, Kathleen
Kinesiology

subject: Body Image, Leisure time, Spinal cord Injury, Self-Regulatory Strategies and Behaviours, Functional Capabilities

abstract:
Body image is an important component of physical and psychological health. Cash's
(2002) cognitive-behavioural model of body image is useful for understanding factors
related to body image, such as body composition and leisure time physical activity
(LTPA). Changes in body composition and LTPA following spinal cord injury (SCI)
may increase the risk of developing an unhealthy body image and may jeopardize the
overall health and well-being of people with SCI. Unfortunately, little research had been
conducted to explore factors related to body image in the SCI population.

The object of the current thesis was to examine body image in people with SCI, within
the framework of Cash's (2002) model. Specifically, we examined the relationships
between appearance and functional satisfaction, LTPA, and body composition in 61 men
and women with SCI. Pearson's correlations were calculated to examine the relationship
between body composition and body satisfaction. In order to compare body satisfaction
between men and women who engaged in some LTPA versus no LTPA, separate 2 (sex) x
2 (LTPA) ANOVAs were calculated for appearance satisfaction and functional
satisfaction.

We hypothesized that body composition would be negatively related to appearance
satisfaction and functional satisfaction such that higher body weight, percentage body fat
and waist circumference would be associated with lower levels of satisfaction. Further,
we hypothesized that after controlling for body composition, participants who engaged in
LTPA would have more appearance and functional satisfaction than those who did not.Finally, we hypothesized that body satisfaction would be more strongly related to
moderate-intensity LTPA versus mild-intensity LTPA, and resistance-LTPA versus
aerobic-LTP A.

In partial support of our hypothesis, body composition was significantly related to
appearance satisfaction for women only. Body composition was not significantly related
to functional satisfaction for men or women. The results of the ANOVAs indicate that
women were more dissatisfied with their appearance than men. However, contrary to
hypothesis, appearance satisfaction did not differ between men or women who engaged in .
LTPA versus those who did not. For men and women, those who engaged in mild or
moderate intensity LTPA were less satisfied with their physical function than those who
did not. Further, participants who engaged in resistance-LTPA were less satisfied with
their physical function that those who did not.

Results are discussed within the framework of Cash's model. Findings suggest that
people who engage in LTPA are less satisfied with their bodies than people who do not.
This finding was surprising because LTPA has been shown to improve body image in the
SCI population (Hicks et al., 2003). However, dissatisfaction with physical appearance or
physical function may motivate individuals to engage in LTPA. The theoretical and
practical implications of the current thesis are discussed. Prospective research is
necessary to further understand the directionality of the relationship between the
constructs of Cash's (2002) model, and to test SCI-specific variables as potential
mediators and moderators of the relationship between LTPA and body image.

abstract: Thesis

abstract: Master of Science (MSc)


title: Traits underlying phosphorus use by the extremophyte Eutrema salsugineum

contributor:
Weretilnyk, Elizabeth
Biology

subject:
Phosphate deficiency
Extremophyte
Thellungiella salsuginea

abstract: The objective of this thesis was to study the response of Eutrema salsugineum (Yukon) plants to low phosphate (Pi) using seedlings and four- week-old plants grown on media formulated with variable phosphate (Pi). Seedlings showed similar root architecture whether grown with high Pi or without added Pi. Four-week-old plants grown with 0 or 2.5 mM Pi added to the soil had the same shoot biomass and relative growth rates. Confirmation that plants on low Pi were Pi-deficient despite lacking a Pi-starvation phenotype was provided by the increased expression of Pi-starvation-inducible genes (notably EsIPS2) in Pi-deprived plants. We also found that seedling roots on media lacking Pi did not acidify their rhizosphere nor did they show increased phosphatase secretion or phosphatase activity relative to roots of Pi-sufficient seedlings. In soil-grown plants, leaf P remobilization was slower during dark-induced senescence of Eutrema relative to similarly treated, Pi-starved Arabidopsis. Also related to metabolism, in vitro assays showed that the ratio of maximal PPi- and ATP- dependent phosphofructokinase activities approximated 1:1 and 2:1 for Eutrema leaf and root extracts, respectively, with no Pi-responsive changes found and, relative to Arabidopsis, Eutrema phosphoenolpyruvate carboxylase activities were high. The enzyme activities suggest Eutrema operates glycolytic by-passes under Pi sufficient and deficient conditions. Finally, transcripts for the transcription factors Phosphate Starvation Response 1 (PHR1) and WRKY75 were not Pi-starvation-inducible and were more abundant in Eutrema leaves than in leaves of Pi-deprived Arabidopsis. Global gene expression showed the leaf and root transcriptomes to be about 90% similar between 0 and 2.5 mM Pi- treated plants with 2,901 differentially expressed genes detected by DESeq2. In summary, Eutrema displays few Pi-starvation responsive traits whether those traits reflect changes at the level of gene expression or plant morphology, behaviour consistent with a specialist that is continuously primed for Pi starvation.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Characterization and Modeling of a MEMS Micromirror Array for Use in an Adaptive Optics System

contributor:
Kleiman, R. N.
Engineering Physics

subject: characterization, modeling, MEMS micromirror, array, adaptive optics system, DMD, analog operation, modulation

abstract:
 In recent years, deformable micromirror arrays have become the focus of several attempts to create cost efficient adaptive optics systems for vision science. Conversely, the Digital Micromirror Device™ (DMD™) has been overlooked by several applications, including adaptive optics, due to its inherent bistability. As a means of addressing this limitation, this thesis suggests multiple methods to demonstrate the feasibility of analog operation of the DMD™. The first step in this process involves the characterization of the DMD™ by means of an automated, optical measurement system. This system was developed to actively monitor the angular deflection of individual micromirrors in the MEMS array. Two key mechanical properties of the microstructure - the natural frequency and the quality factor - are determined through analysis of the micromirrors' recorded dynamic behaviour. Further, through automation of the characterization setup, an investigation of device uniformity is
presented exposing a clear trend in the measured micromirror properties over 160 tested mirrors in the DMD™ array. This linear trend is attributed to the variation in thickness of the torsional hinges as a result of the sputtering deposition process. Using the DMD™ characteristics discovered through experimentation, a computationally inexpensive, one-dimensional model based on the fourth order Runge-Kutta numerical method is constructed to simulate the response of the DMD™ micromirrors to user defined input voltage waveforms. Simulations are initially used to exhibit the validity of the model for existing DMD™ voltage patterns through a comparison with measured micromirror responses, and subsequently used to demonstrate two proposed methods of analog operation. The first method creates a limited form of analog control by varying the amplitude of 16 analog bias voltage lines, whereas the second method provides complete analog operation of the DMD™ using high frequency pulse width modulation of the underlying address circuitry.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: THE ROLE OF GLYCOGEN SYNTHASE-3α/β IN THE PROGRESSION AND REGRESSION OF ATHEROSCLEROSIS

contributor:
Werstuck, Geoff
Chemical Biology

abstract:
Atherosclerosis is a major underlying cause of cardiovascular disease; however, the molecular mechanisms by which cardiovascular risk factors promote the development of atherosclerosis are poorly understood. Recent evidence from our laboratory suggests that endoplasmic reticulum (ER) stress signaling through glycogen synthase kinase (GSK)-3α/β is involved in the activation of pro-atherosclerotic processes. The objective of this study was to examine the role of ER stress-GSK3α/β signaling on the progression and regression of atherosclerosis in a mouse model system.
We first investigated the effects of attenuating ER stress or inhibiting GSK3α/β in a low density lipoprotein receptor deficient (Ldlr-/-) mouse model of atherosclerosis. Mice treated with the ER stress alleviator 4-phenylbutyric acid (4PBA) or the GSK3α/β inhibitor valproate (VPA) have significantly reduced lesion areas and volumes, indicating that these treatments attenuated the development of atherosclerosis.
Next, we examined the effects of 4PBA or VPA treatment in Ldlr-/- mice with established lesions. These treatments inhibited the progression of atherosclerosis in established plaques, but we did not see any evidence of plaque regression. However, the plaques appear to be more stable and less prone to rupture.
Lastly, to help determine the mechanism by which GSK3α/β is involved in atherosclerosis, cell culture experiments were performed to characterize GSK3α or GSK3β deficient macrophages. Bone marrow derived macrophages were obtained from Ldlr-/- mice with myeloid specific GSK3α or GSK3β deficiency, and were cultured in the presence of the ER stress inducing agents thapsigargin (Tg) or tunicamycin (Tm). The absence of GSK3α attenuated M1 polarization, but did not significantly alter cell viability or the expression of genes involved in lipid biosynthesis and uptake. The deletion of GSK3β minimally affected apoptosis induced by Tg or Tm treatment. In contrast, the deletion of GSK3α and GSK3β significantly improved cell viability.
	These data support the importance of ER stress-GSK3α/β signaling in atherogenesis. The pharmacological attenuation of ER stress or inhibition of GSK3α/β impedes the development of atherosclerosis in Ldlr-/- mice and appears to promote the stabilization of existing lesions. This may be due in part to a reduction in the pro-inflammatory M1 phenotype associated with the inhibition of the GSK3α homolog.

abstract: Thesis

abstract: Master of Science (MSc)


title: Diffusive Loss of Non-Aqueous Phase Organic Solvents from a Disk Source

contributor:
Dickson, Sarah E.
Civil Engineering

subject: diffusive loss, non-aqueous, phase, organic solvents, disk source, instantaneous

abstract:
 Matrix diffusion from planar fractures was studied both mathematically and through physical model experiments. A conceptual model was developed based on previous work by Parker (1994) and Crank (1956). Mathematical models were developed to simulate diffusion from 2D and 3D instantaneous disk sources and a 3 D continuous disk source. The models were based on analytical solutions previously developed by Carslaw and Jaeger (1959). Analytical solution is not available for the total mass diffused into the porous matrix for a 3D continuous disk source, and it was therefore calculated through the summation of the iso-concentration lines, which were assumed to be a semi-spherical shape.

 The mathematical simulations indicated that the 2D scenario produces significantly different results from the 3D scenario, the time for mass disappearance is significantly larger for continuous sources than for instantaneous sources, the normalized concentration generally decreased over time for instantaneous sources while it increased over time for continuous sources, diffusion rates decrease significantly over time and space, and the normalized mass loss from the source zone never reaches 1 for continuous sources due to the semi-infinite integral. The simulations also showed that disappearance times increase exponentially with increasing source radii and matrix porosity, and decrease with increasing aqueous-phase NAPL solubilities.

 The observations from the physical model experiments were very close to the simulated data at z = 0, validating the 3D mathematical models for this elevation. A plot of the observed vs simulated data did not reveal any trends, indicating that the majority
of the differences can be attributed to experimental error. The experimental concentrations were below the method detection limit at depths of 3 and 6 cm however, indicating that either the experiments should have been conducted over a longer time period or a more sensitive analytical method should have been employed, to enable model validation at these depths.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The Role of Cytoskeletal Signaling in Lens EMT

contributor:
West-Mays, Judith
Biomedical Engineering

abstract:
Cataract is an opacification of the ocular lens and is the leading cause of visual impairment and blindness worldwide. The only form of treatment is removal of lens cells through cataract surgery, however, this procedure can lead to complications, the most common of which is the development of a secondary form of cataract known as posterior capsule opacification (PCO). PCO is caused by lens epithelial cells not removed during cataract surgery, which have the capacity to migrate to the previously cell-free posterior capsule. Here, these remnant cells can undergo epithelial-mesenchymal transition (EMT) into myofibroblasts that impair vision through the promotion of a fibrotic environment involving excessive deposition of extracellular matrix (ECM) and capsule wrinkling. This process is mediated by surgery-induced activation of transforming growth factor (TGF)-β. Remodeling of the actin cytoskeleton, mediated by the Rho family of GTPases, plays a key role in EMT, however, how actin dynamics affect downstream markers of EMT has not been fully determined. Our previous work suggests that myocardin related transcription factor A (MRTF-A), an actin-binding protein, and MMP-9 may be important mediators of lens EMT. The aim of the current study was to determine the requirement of RhoA/ROCK signaling in mediating TGFβ-induced cell-cell contact disassembly and ultimate α-smooth muscle actin (αSMA) expression, key transdifferentiation events.
Using a rat lens epithelial explant model, my work demonstrated that Y-27632, a ROCK inhibitor, prevented TGFβ-induced nuclear accumulation of MRTF-A, E-cadherin/β-catenin complex disassembly, and expression of MMP-9 and αSMA. Furthermore, using a novel inhibitor specifically targeting MRTF-A signaling, CCG-203971, my work further demonstrated that MRTF-A nuclear localization and activity is essential to the induction of αSMA expression. Lastly, using rat lens explants treated with recombinant human MMP-9 (rhMMP-9) and MMP-9 KO mouse lens explants I demonstrated a key role for MMP-9 in the proteolytic processing and regulation of membrane-associated E-cadherin.
Overall, the findings outlined in this thesis strongly suggest that ROCK-mediated cytoskeletal signaling is indispensable to lens EMT, and involved in several key aspects of the TGF signaling pathway. The role of canonical TGF signaling through Smads has been widely studied in the lens, however, only recently has the academic lens community begun to appreciate the involvement of other signaling pathways. As a result, our understanding of how actin dynamics are involved in lens EMT is still at an early stage. The work in my thesis progresses our knowledge of the interplay between cytoskeletal signaling and its specific downstream mediators that result in a sustained EMT response. This work also has implications beyond lens EMT, impacting our understanding of the pathogenic processes common to a broad array of fibrotic diseases. Importantly, my findings have implications for the therapeutic targeting of ROCK-mediated signaling in the prevention of fibrosis of the lens, and other tissues.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: New Large Neighborhood Interior Point Methods For Semidefinite Optimization

contributor:
Terlaky, Tamas
Computational Engineering and Science

subject: Interior point methods, Semidefinite Optimization, Small Neighborhood Algorithm

abstract:
In this thesis, we extend the Ai-Zhang direction to the class of semidefinite
optimization problems. We define a new wide neighborhood N(τ1 ,τ2 ,η) and,
as usual, we utilize symmetric directions by scaling the Newton equation with
special matrices. After defining the "positive part" and the "negative part"
of a symmetric matrix, we solve the Newton equation with its right hand side
replaced first by its positive part and then by its negative part, respectively.
In this way, we obtain a decomposition of the usual Newton direction and use
different step lengths for each of them.

Starting with a feasible point (X^0 , y^0 , S^0) in N(τ1, τ2 , η ), the algorithm terminates
in at most 0(η√( κ∞n)log(1/ε) iterations, where κ∞ is a parameter
associated with the scaling matrix and ε is the required precision. To our best
knowledge, when the parameter η  is a constant, this is the first large neighborhood
path-following Interior Point Method (IPM) with the same complexity
as small neighborhood path-following IPMs for semidefinite optimization that
use the Nesterov-Todd direction. In the case when η is chosen to be in the order
of √η, our complexity bound coincides with the known bound for classical
large neighborhood IPMs.

To make this thesis more accessible to readers who are new in this area, we
start with a brief introduction to IPMs and SDO. The basic concepts and
principles of IPMs and SDO are presented in Chapter 2 and 3.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: X-RAY FLUORESCENCE MEASUREMENT OF IRON ACCUMULATION IN SKIN AS A SURROGATE MARKER FOR IRON LEVELS IN CRITICAL ORGANS AND TOTAL BODY IRON BURDEN

contributor:
Farquharson, Michael J
Medical Physics

subject: x-ray, iron, x-ray fluorescence, skin, liver, thalassemia

abstract:
This thesis investigates the use of x-ray fluorescence (XRF) measurements of skin iron
concentration as a non-invasive surrogate marker for total body iron burden. Rats were
overloaded with iron dextran via intraperitoneal injection to investigate trends in iron
accumulation in skin and organs. The skin, heart, liver, and kidney of the animals were
collected and the iron concentrations were measured using the Huber XRF system and
the polarized energy dispersive x-ray fluorescence (PEDXRF) system. When measured
in the Huber XRF system, a very strong quadratic correlation was found between skin
iron concentration and liver iron concentration (R2=0.92). In the same system, skin
iron concentration had a moderately strong linear correlation with heart and kidney iron
concentration (R2=0.53 and R2=0.65, respectively). Measured in the PEDXRF system,
heart and kidney iron concentrations were again linearly correlated with skin iron
concentrations (R2=0.34 and R2=0.31, respectively). Liver iron concentration again
showed a quadratic correlation with skin iron concentration (R2=0.64). Therefore, it
was demonstrated that skin iron concentrations can act as a surrogate marker for organ
iron concentrations in rats, especially for the liver. The feasibility of using an Olympus
Innov-X Delta Professional Handheld XRF Analyzer, a commercial portable x-ray
fluorescence (PXRF) device, as a tool for in vivo skin iron analysis was investigated.
The same rat skin samples measured in the previous experiment were measured using
the PXRF device and compared with the organ iron concentrations as measured using
the Huber XRF system. The heart and kidney showed linear correlations with skin iron
concentration (R2=0.45 and R2=0.36, respectively). The liver showed the strongest
correlation with a moderately strong quadratic correlation with R2=0.74. It was
determined that using Beam 3 in the Soil mode of this device resulted in equivalent
and effective dose rates of 230±10mSv/min and 2.3±0.1mSv/min, respectively. Thus,
the PXRF device has shown promise as a potential tool for measuring in vivo skin
iron levels.

abstract: Thesis

abstract: Master of Science (MSc)


title: Femtosecond Laser Micromachining of Lithium Niobate

contributor:
Kleiman, Rafael N.
Preston, John S.
Engineering Physics

subject: femtosecond, laser, micromachining, lithium niobate, photonic, MEMS, pulses, amorphous

abstract:
 Lithium niobate is an important photonic material that has potential applications in MEMS. Unfortunately, it is difficult to process using conventional methods. This thesis is an exploratory study to determine the viability of using a femtosecond laser as a fabrication tool for lithium niobate. Unexpectedly, a rich range of behaviour, likely arising from the complex material structure and composition, was discovered. Depending on the processing conditions, it was demonstrated that machining can either result in deep, high-aspect ratio grooves with minimal surrounding damage or dramatic modification of the lithium niobate to great depths with very little material removal.

 When machining grooves, increasing the effective number of pulses Neff (i.e. decreasing cutting speed) gave rapidly increasing ablation depths until a threshold was reached, after which the grooves were nearly filled with amorphous material. The depth of these amorphous channels rapidly saturates and becomes nearly independent of Neff. The ablation depth dependence on fluence showed gentle and strong ablation regimes. The amorphous channel depth depended almost linearly on fluence. Subsequent laser passes over amorphous channels eventually removed the amorphous material from the groove, indicating a dependence on the time between laser pulses. Crystal orientation was not a factor.

 The results are understood in terms of incubation and wave guiding. The first pulses ablate some material and incubate a channel of material below the surface. With further pulses, increasing incubation accelerates ablation. At the threshold Neff, the absorption coefficient has increased enough that the next pulse is able to melt a
significant amount of material, which expands to fill the groove. It is suggested that, initially, the amorphous material is able to guide subsequent pulses to the bottom of the channel, resulting in a very slowly increasing depth with Neff. Subsequent passes cause ablation once again since compositional changes in the amorphous material have relaxed. Irradiated samples appear thermally reduced, which would create colour centres leading to increased absorption and thus incubation.

 Femtosecond lasers are indeed able to create MEMS structures. Multiple passes in the ablation regime yielded deep grooves, with laser polarization perpendicular to the groove giving the best results. Fabrication of micro-cantilevers and bridges was demonstrated.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: A Study of Music and Its Ability to Give Voice: A Photo-Elicitation Project Involving Youth In-Care and the Interpretation of Visuals

contributor:
Sinding, Christina
Social Work

subject:
child welfare
youth consultation
youth in-care
photo-elicitation
youth voice
music
postmodernism
visual research methods
youth participation

abstract:
In 2017 the Ontario government moved forward with new child welfare legislation, Bill 89, spelling out that the 47 Children’s Aid Societies in Ontario will be much more ‘child-centric’. I explore the historical context of the ‘child-centric’ language and commitments in the new Act, including tracing its origin by the Act’s incorporation of the Katelynn Principle and Article 12 of the 1989 United Nations Convention On The Rights Of The Child.

	How best to consult youth in-care is an essential, but a mostly unanswered question. Children Aid Societies across the province have a unique opportunity to implement alternative methods in engaging young people in consultation, should they pan out as viable and reliable strategies when consulting youth in-care. Tradition interview approaches are not always the best strategies when engaging youth. Visual research methods, such as photo-elicitation, have the potential of offering useful insights into children’s perspectives and experiences.

	The focus of my thesis is youth voice. I explore this topic through a study with young people in-care involved in a music group. I used focus groups and photo-elicitation as methods for data collection.  An important question addressed by my thesis is whether a visual research method, such as photo-elicitation, helps in the consultation process with young people and whether some of the claims made about the approach are accurate when working with youth. Specifically, I explored claims made about photo-elicitation helping with increasing 'emotional type talk' and inquired into how the method may enhance the consultation process with young people. I consider these questions in the context of important epistemological and theoretical debates about arts-informed and visual research methodologies.

	Five youth who had involvement of being in-care and were a part of a music group at a local Children’s Aid Society participated in my study. My study found that the youth overall felt consulted and did feel a degree of influence in shared decision making with being in-care. My study also showed that although photo-elicitation did not generate more ‘emotional-type talk’, it does appear to enhance self-confidence, which seemed to support meaningful participation in the interview process. Although much more needs to be explored with the application of visual research methods, and social science researchers should be cautious in making exaggerated claims in support of the approaches, youth in-care can surely benefit from visual research methods such as photo-elicitation.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: A SURVEY OF THROMBOSIS SPECIALISTS ON THE PRACTICAL MANAGEMENT OF EXTENSIVE DEEP VEIN THROMBOSIS AND A PROTOCOL FOR A RANDOMIZED TRIAL

contributor:
Crowther, Mark
Health Research Methodology

subject:
Survey
Extensive deep vein thrombosis

abstract:
BACKGROUND: Though direct oral anticoagulants (DOACs) have become a standard of care in the treatment of acute deep vein thrombosis (DVT), it is our observation that physicians tend to initiate heparin or low-molecular-weight heparin, hereafter called “heparin”, for the treatment of extensive DVT or phlegmasia cerulea dolens (PCD). This might be due to a perception that heparin might relieve DVT-related symptoms more quickly than DOACs. Whether these assumptions are true has not been evaluated.
METHODS: We conducted a survey of thrombosis specialists in North America to explore the practical management of anticoagulant therapy in patients with extensive DVT, and the underlying reasons for the selection of heparin over DOACs. A cross-sectional, web-based survey was distributed to thrombosis specialists who are members of four thrombosis societies.
RESULTS: Eighty-nine respondents provided consent. Most respondents selected DOACs over heparin in a case scenario representing mild DVT-related symptoms and limited thrombus involvement (81% vs. 19%). Most respondents selected heparin over DOACs in a case scenario representing early stage PCD (84% vs.16.3%) or a patient with high bodyweight (72% vs. 28%). In a case scenario representing extensive DVT, 57.4% of the respondents selected heparin, whereas, 42.6% selected DOACs. In the respondents who selected heparin over DOACs, the major reason was that heparin might relieve DVT-related symptoms more quickly because of its anti-inflammatory effects.
DISCUSSION: Severity of DVT-related symptoms, thrombus extent, and bodyweight play a role in the selection of anticoagulant therapy. Despite a lack of evidence to support the hypothesis with respect to which anticoagulant is superior, most thrombosis specialists selected heparin over DOACs in patients with severe DVT-related symptoms and extensive thrombus involvement. Observation of variations in the selection of anticoagulant therapy for the treatment of extensive DVT also indicates that clinical trials in this patient population are needed.

abstract: Thesis

abstract: Master of Science (MSc)


title: STRATEGIES TO IMPROVE SKELETAL MUSCLE PROTEIN TURNOVER DURING DIETARY ENERGY RESTRICTION

contributor:
Phillips, Stuart
Medical Sciences

subject:
Energy Restriction
Skeletal Muscle

abstract: Weight loss through dietary energy restriction (ER) is an effective method to promote fat mass loss. However, a negative consequence of ER is the loss of lean body mass (LBM), particularly skeletal muscle, which is induced by an imbalance between rates of muscle protein synthesis (MPS) and muscle protein breakdown (MPB). Increased protein intake and resistance exercise (RE) during ER promote the retention of LBM. Currently, the relative contribution of MPS and MPB to diet-induced LBM loss, and the effect of protein intake and RE on these variables is not well characterized. In Study 1 we compared the acute (hour-to-hour) MPS response to the ingestion of whey and soy protein, before and after 14 days of ER (-750kcal/d). The results of Study 1 indicated that whey protein was superior to soy protein in stimulating MPS before and after ER. In Studies 2 and 3 we examined the effect of 10 days of a marked 40% energy restriction on acute postabsorptive MPS and MPB and integrated (day-to-day) MPS. Using unilateral RE, we examined the effects of protein (1.2g protein/kg/g or 2.4g protein/kg/d) at rest and in combination with resistance exercise. The results of Study 2 showed that there were no changes in acute MPB or markers of proteolysis with ER. The results of Study 3 indicated that acute and integrated MPS were reduced following ER at both protein levels (1.2g protein/kg/g or 2.4g protein/kg/d), but RE was able to prevent this decline. Taken together, these studies demonstrate that reductions in MPS are the likely reason for LBM loss during short-term dietary energy restriction, and strategies such as RE and high quality protein intake can help to prevent the decline in MPS. These findings provide information for the design of weight loss programs that wish to preserve skeletal muscle.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Dietary energy restriction is commonly used to promote weight/fat loss; however, a potential negative consequence of dietary energy restriction is the loss of skeletal muscle mass. This thesis examines the impact of dietary energy restriction on the two processes that regulate skeletal muscle mass: muscle protein synthesis and muscle protein breakdown. Additionally, this thesis investigates the role of protein intake and resistance exercise as strategies to prevent diet-induced changes in muscle protein synthesis and breakdown. The studies within this thesis demonstrate that during energy restriction rates of muscle protein synthesis are reduced whilst muscle protein breakdown is unchanged. Importantly, consuming high quality protein such as whey protein and performing resistance exercise prevent the diet-induced decline in rates of muscle protein synthesis. These findings provide new and insightful information for the design of weight loss programs that aim to preserve skeletal muscle whilst also promoting the loss of body fat.


title: HEALTH TECHNOLOGY ASSESSMENT FOR MITRACLIP SYSTEM IN PATIENTS WITH MITRAL REGURGITATION

contributor:
Mehta, Shamir
Health Research Methodology

subject:
Mitral Regurgitation
MitraClip
Surgery

abstract: Approximately 2% of the population have mitral regurgitation (MR) and many may be not tolerant for mitral valve surgery. The objective of this thesis was to investigate the comparative safety, effectiveness, and cost-effectiveness of percutaneous mitral valve repair using MitraClip System for patients with severe MR. Articles in MEDLINE, Embase, CNKI, and the Cochrane Library published from 1997 to February 2017 were searched for evidence of safety and effectiveness. A systematic review was conducted to address the uncertainty in the safety and effectiveness of MitraClip system in patients with MR. A cost-effectiveness analysis and cost-utility analysis in U.S. settings was conducted to address the uncertainty in health economic evaluation for the MitraClip system. One randomized trial and seven observational studies were included in the systematic review. The pooled data show that 30-day, one-year and two-year survival are similar in MitraClip arm and surgery arm. Residual MR occurs more frequently after MitraClip therapy than surgery, especially in younger patients, functional MR patients, and patients whose LVEF<50%. The risk of 30-day major adverse event from lower odds ratio appeared to be lower in older patients and patients whose LVEF≥50%.For economic evaluation, the base case incremental costs per LY and per QALY were $ 28,217.18 and $27,344.38 US dollars, respectively. Results were most sensitive to alternative assumptions regarding time horizon and long-term survival. Therefore, low quality of evidence due to lack of conclusive RCT data suggested that MitraClip system may provide improvements in MR, patients’ quality of life and survival advantage. It is cost-effective as threshold of $50,000 U.S. dollars per QALY gained for high surgical risk patients. Future RCT designed to reduce confounding and lessen participant attrition, which have adequate sample size, consistent reporting of outcomes, and adequate length of follow-up period will better evaluate the clinical benefits of the MitraClip System.

abstract: Thesis

abstract: Master of Health Sciences (MSc)

abstract: Mitral regurgitation is an abnormal leakage of blood back into the left heart chambers. About 2% of the population who have chronic mitral regurgitation are elderly and are at high risk for surgery. For such patients, a treatment has been proposed that involves a catheter puncturing the skin of the groin and travelling all the way to the affected valve to deploy a device that clips and repairs the valve leaflets (a mitral valve clip). This thesis sought to compare the safety, effectiveness and cost-effectiveness of mitral valve clips with current standards of care in patients at high risk for surgery. To address this question, we searched, critically appraised, and collated existing research evidence. We found that this new treatment was not harmful and may provide a survival advantage. In addition, the approach may be cost-effective when compared to current stand of care in patients at high risk for surgery.


title: The Performance of Tuned Liquid Dampers with Different Tank Geometries

contributor:
Tait, Michael J.
Civil Engineering

subject: conical, dynamic vibration absorber, horizontal-cylindrical, hyperboloid, liquid sloshing, mechanical model, parabolic, rectangular, rectangular, strucutre-TLD system, structural vibration sloped-bottom, tank, triangular, tuned liquid damper, vertical cylindrical

abstract:
 Tuned Liquid Dampers (TLDs) are increasingly being used to suppress the dynamic vibration of tall buildings. An equivalent mechanical model is essential for rapid analysis and design of a TLD. The most common TLD tank geometries are circular, annular and rectangular. Rectangular tanks are utilized for 1-D and 2-D TLDs, whereas circular and annular are usually applied to axisymmetric structures. The amount of fluid that participates in the sloshing motion is directly influenced by the tank geometry. Although not commonly used, a TLD having a curved-bottom tank is expected to perform more effectively due to its relatively large value of effective mass. The main objective of this study is to develop mechanical models for seven TLDs with different tank geometries including the curved-bottom case, and to theoretically investigate the performance of rectangular, vertical-cylindrical and horizontal-cylindrical TLDs.

 Potential flow theory, linear long wave theory, Lagrange's equations and virtual work method are employed to develop the equivalent mechanical model parameters of TLDs with rectangular, vertical-cylindrical, horizontal-cylindrical, hyperboloid, triangular, sloped-bottom, and parabolic tank geometries. A rectangular, vertical-cylindrical and horizontal-cylindrical TLD are selected for further study using a single-degree-of-freedom
(SDOF) model and a two degree of freedom structure-TLD system model applying the derived equivalent mechanical parameters.

 The dynamic characteristics of the TLDs as a SDOF system are investigated. The mechanical model is verified by comparing calculated values with experimental results for a rectangular TLD. The free surface motion, sloshing force and energy dissipation are found to be dependent upon the excitation amplitude. Analytical results also indicate that the horizontal-cylindrical TLD possesses the greatest normalized sloshing force and energy dissipation among the TLDs considered.

 The performances of various TLDs installed in a structure are studied in terms of effective damping, efficiency and robustness. Tuning ratio, structural response amplitude, mass ratio and liquid depth are adjusted to investigate their affect on the performance of the studied TLDs. Performance charts are developed and subsequently used to present the results. It is found that small liquid depth ratio and large mass ratio can lead to a robust structure-TLD system with small relative motion ratio between the structure and the vibration absorber. Comparisons of performance between the three TLDs are made and it can be concluded that the horizontal-cylindrical TLD is the most robust and effective device with the smallest relative motion ratio.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Quantum Well Intermixed Two Section Superluminescent Diodes

contributor:
Thompson, David
Engineering Physics

subject: Quantum intermixing, Superluminescent Diodes, Planck's constant, Strain and lattice mismatch

abstract:
Superluminescent diodes have become important for various applications, such as for biomedical imagining, due to their broad spectral width and high power.

This thesis demonstrates two-section superluminescent diodes fabricated using quantum well intermixing with strained Ga_0.75sln_0.25As quantum wells, grown on a GaAs substrate. A 100 nm capping layer of Ga_0.515In_0.485P grown at low temperature and having an excess of phosphorus, was removed from one section of the device to produce a relative bandgap shift between sections after rapid thermal annealing. The devices emitted at a wavelength of ~1μm with 60 nm of spectral width, and up to 38 mW of power at 20°C, depending on the currents applied to each section.

The combination of the spectral output from the two quantum well intermixed sections resulted in the broad spectral width. Angled facets at 7 ° were used to prevent the device from lasing. Additional power improvements were seen following the thermal anneal when a SiO2 capping layer was used on both sections. Depending on the applied currents, each section required 1.5 V to 3.0 V; and failed at 5.3 V ± 0.5 V.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Uncertainty Analysis of a Two-Dimensional Hydrodynamic Model

contributor:
Guo, Y.
Moin, S.
Civil Engineering

subject: uncertainty analysis, two-dimensional, hydrodynamic model, FOSM method

abstract:
 The objective of this thesis was to undertake an uncertainty analysis on the outputs from a two-dimensional hydrodynamic model. The analysis utilized an application of the Resource Management Associates' RMA2 model for the Upper St. Lawrence River in Ontario, Canada. Two uncertainty analysis methods, First-Order Second Moment (FOSM) and Monte Carlo analysis, are applied to calculate the uncertainty in water levels and velocities computed by the model.

 Both uncertainty analysis methods can be applied together with two-dimensional hydrodynamic modelling, but based on the findings of this work, the FOSM method is preferred. First, FOSM estimates of uncertainty are slightly larger than those obtained using Monte Carlo analysis. Thus, FOSM provides a conservative estimate of the
uncertainty, a positive characteristic. Second, the FOSM method is simpler to apply than
Monte Carlo analysis, requiring less information to describe the model inputs, fewer
model executions and computations to calculate the uncertainty. Third, FOSM provides
an immediate indication of the primary contributors to the uncertainty in the output, where Monte Carlo analysis requires additional effort to do the same.

 The model input that contributed the most to the uncertainty in the model outputs is the bottom resistance represented in RMA2 using Manning's n. The uncertainty in Manning's n is large and the model is sensitive to the parameter. As a result, a significant amount of uncertainty in the model outputs is contributed by this parameter.

 Uncertainty analysis is a practical addition to the two-dimensional hydrodynamic
modelling process. The effort required to complete an uncertainty analysis using the
FOSM method is minimal and the resulting insight is meaningful. It provides
information to the model developer, quantifying how good the model actually is. It also
provides a measure of the accuracy of the model for future model users or clients using
hydrodynamic modelling outputs.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Application of Best Estimate and Analysis of Uncertainty Methods to CANDU Channel Power

contributor:
Luxat, J.C.
Engineering Physics

subject: application, best estimate methods, uncertainty, CANDU, channel, power, global flux, gamma ray energy

abstract:
 Best estimate and analysis of uncertainty methods are used to examine the variability of
the H factor, which converts the global flux in a lattice cell to power. The assumption of a
constant H factor is tested, by examining the sensitivity of the components of the H factor to perturbations in reactor conditions, such as, moderator temperature, boron content in the moderator, moderator purity, RIH temperature, ROH pressure, and exit burnup. The local flux profile, which is a component of the H factor, is calculated for a typical CANDU reactor lattice cell using WIMS 2.5d. Another component of the H factor, the distribution of fission energy in a lattice cell, is found by exploring the location of each source of energy released from a fission event. To examine the location of the gamma ray energy deposition a two dimensional Monte Carlo code was created and subsequently benchmarked against an analysis done by C.R.Boss. Using the Monte Carlo code, the best estimate of the percentage of gamma ray energy deposited in the heat transport system was found to be 83.7%. The moderator temperature and the exit channel burnup are shown to have the largest influence on the H factor, which was found to vary between 99.6% and 100.4% of the best estimate value.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Light Emission From Rare Earth-Doped Silicon Oxide Films Deposited By ECR-PECVD

contributor:
Mascher, Peter
Engineering Physics

subject: light emission, ECR-PECVD, Luminescence, PL intensity

abstract:
Silicon oxide films (oxygen-rich or silicon-rich) doped with various rare-earth (RE) [cerium (Ce), terbium (Tb), europium (Eu) and erbium (Er)] elements have been by deposited by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD). The successful in-situ incorporation of high concentrations of RE elements has been confirmed by Rutherford backscattering spectrometry (RBS), and the optical properties of the films were analyzed by Photoluminescence (PL) spectroscopy.

 Ce, Tb, Eu and Er related emission was observed from the films with corresponding doping and was found to be sensitive to RE concentration, the presence of Si nanoclusters (Si-ncs) and annealing induced structural evolution. The significant enhancement of Ce^3 + emission in Ce-doped oxygen-rich films under annealing in flowing N2 at 1200 °C was found to be related to the formation of cerium silicate whose presence was confirmed by Fourier transform infra-red (FTIR) spectra and high-resolution transmission electron microscopy (HR-TEM) images. The observation of intense Tb^3+ emission from Tb-doped oxygen-rich films under nonresonant excitation revealed the presence of indirect excitation processes. The organic ligands introduced from the Tb(tmhd)3 precursor during deposition was considered as the possible sensitizer. The presence of Si-ncs in Ce or Eu-doped silicon-rich films resulted in the quenching of both RE and Si-ncs PL, while in Tb or Er-doped silicon-rich films the coupling between Si-nes and RE ions can excite RE-related emission efficiently. The formation of Si-ncs with sizes of 2-3 nm in Tb-doped silicon-rich films under annealing in flowing N2 at 1100 and 1200 °C was revealed by HR-TEM images.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Kinetics of CO/CO2 Reaction with MnOx/TiOx-CaO-SiO2 Slags

contributor:
Coley, Kenneth S.
Materials Science and Engineering

subject: kinetics, reaction, slags, metal oxide, basicity

abstract:
Knowledge of the interfacial reactions between CO/CO2 and transition metal oxide containing slags is more important to understand various metallurgical processes. The present research studied the kinetics of reaction between CO/CO2 and MnOx/TiOx containing Slags. Measurements of the rate of interfacial reaction between CO/CO2 and MnOx/TiOx -CaO-SiO2 Slags were made using 13CO2-CO isotope exchange technique. The dependence of
rate constant with respect to the effects of oxygen activity, MnOx/TiOx content, slag basicity and temperature was discussed. It is found that the apparent rate constant increases with increasing MnOx/TiOx content, slag basicity and temperature and decreases while increasing oxygen activity. The apparent rate constants obtained for MnOx/TiOx containing slags show similar behavior to that of FeOx containing slags and the rates gradually increase for TiOx, FeOx and MnOx containing slags at same experimental conditions. The rate constant expressions for MnOx/TiOx containing slags are obtained by using a single charge transfer model. Comparison of calculated and measured rate constants
shows that there is a good fit between the two, which implies that the single charge transfer model may be generally applicable.

abstract: Thesis

abstract: Master of Science (MSc)


title: Evaluating the Influence of Chain Branching on the Adhesion Strength between Layers in Fused Deposition Modeling

contributor:
Thompson, Michael
Chemical Engineering

subject:
3D Printing
Additive Manufacturing
FDM
Fused Deposition Modeling
Adhesion
Bonding strength

abstract:
Fused deposition modeling (FDM) is gaining an ever increasing attention for its ability to fabricate complex geometry parts and prototypes at lower cost. The technology is striving to produce parts with high mechanical resistance that can withstand and perform under high stress environment. The adhesion strength between layers, transverse strength, is a limiting factor that need to be quantitatively evaluated to further understand and improve the bonding behavior of thermoplastic polymer in FDM. This interfacial adhesion is derived by the diffusion and penetration of polymer chains across the interface allowing the chain entanglement to form a bonding medium.

     This study investigates the bonding behaviour of polylactic acid (PLA) as a function of chain branching. The adhesion strength is quantitatively evaluated by developing and performing a peel test of a two-printed layer samples. It is possible to increase chain branching of PLA by bulk modification with epoxy chain extender. The modification of PLA was carried out using an internal batch mixer with four different concentrations of chain extender. The modified PLA was processed into print filament and characterized by parallel plate rheometry and DSC.

     It was found that the addition of chain extender increased molecular weight and degree of branching of PLA and in return the peel testing results reflected a significant increase in adhesion strength. Such improvement can be attributed to the long branched chains of PLA and its ability to create entanglements between layers. These findings can help in producing better PLA filaments to provide a higher stress resistance for FDM fabricated functional parts.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: Fused Deposition Modeling (FDM) is a recent popular method of plastic 3D printing technique, in which plastic filament is heated to a molten state to be then deposited through a layer-by-layer fashion to successfully fabricate parts. One of the drawbacks of that technology is the low bonding strength developed between layers as compared to strength along the length direction of layers. This study focuses on developing a testing methodology to evaluate the adhesion strength between layers and altering the material structure to maximize such strength. Four types of polylactic acid with different degrees of chain branching were successfully processed, printed and tested. Material with higher degree of branching yielded higher adhesion strength.


title: Parents' attendance, participation and engagement in children's developmental rehabilitation services

contributor:
Rosenbaum, Peter
Rehabilitation Science

subject:
Parent
Engagement
Hard-to-reach
Rehabilitation
Ethics
Family-centred service
Grounded theory
Disability

abstract: Parent engagement in children’s developmental rehabilitation services is thought to be a fundamental component that is needed for children to reach their potential. This is especially true in the approach known as family-centre services – an approach that positions parents as partners in their child’s services. However, service providers and organizations can have difficulty engaging those parents who often miss their child’s appointments. These families are typically referred to as ‘hard-to-reach’, however this label may ascribe ‘blame’ to parents and lead service providers, researchers and policy makers to overlook the social, organizational, and economic barriers that can limit families’ use of services. Chapters 2-4, explore multiple avenues to contextualize parents’ attendance and engagement in children’s therapy services by applying family centred service tenants, Family Stress Theory, and ethical principles. These chapters lay the foundation for the grounded theory study presented in Chapter 5. This study, conducted with parents of children who use developmental rehabilitation services, describes the conditions that affect parent engagement and presents The Phoenix Theory of Parent Engagement to illustrate how parents attend, participate and engage in their child’s therapy service. These results are presented as a metaphorical journey through children’s developmental rehabilitation services in pursuit of child health and happiness. The implications of this theory are presented as they might be relevant to service providers, organizational leadership, and policy makers. These ideas are offered in an effort to inspire a coordinated effort to improve access and excellence in the provision of developmental rehabilitation services for children and families.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Children’s developmental rehabilitation services are thought to be most effective when parents consistently attend, participate and engage in the service. When families do not consistently attend, participate or engage in services they can be labelled as ‘hard-to- reach’. Little is known about why families are hard-to-reach, if there are organizational barriers to service use, and how to promote engagement. This thesis provides a foundation for understanding parent engagement by exploring the clinical application of family-centred service, Family Stress Theory, and ethical principles. A grounded theory study is presented to contextualize parent engagement and explain how parents engage in their child’s developmental rehabilitation services. Service providers, organizational leadership, and policy makers can apply this theory to promote access and engagement in children’s developmental rehabilitation services.


title: EXPLORING COMMUNICATIVE PARTICIPATION OUTCOMES FOR PRESCHOOLERS WITH SPEECH AND LANGUAGE DELAYS

subject:
speech-language pathology
preschool
communicative participation
outcomes

abstract:
This dissertation explored new ways of evaluating outcomes for preschoolers with communication disorders. It identified a need to evaluate outcomes as they relate to a child’s communicative participation and provided initial models for doing this.
Chapter 1 provides the context for the dissertation, discussing the theoretical framework used, the literature on communicative participation outcomes, and Ontario’s Preschool Speech and Language Program (PSLP) and its program evaluation project (the setting for the studies presented in Chapters 4 & 5).
Chapter 2 is a scoping review of the literature exploring the ways in which outcomes for preschoolers with communication disorders have been evaluated. It identifies a gap in the literature related to participation-based outcomes, and thus the need for the work presented in Chapters 4 and 5.
Chapter 3 presents further evidence of both construct and predictive validity of the Communication Function Classification System (CFCS), the classification tool used for PSLP program evaluation. This tool was previously validated for use with children with Cerebral Palsy, and this study provides evidence of its validity with other groups of children.
Chapter 4 explored communicative participation outcomes for preschoolers accessing PSLP services by developing growth curves that predict development of preschoolers’ communicative participation skills. The models provide a first look at the growth of those skills, and show that all children make meaningful change regardless of their communicative function.
Chapter 5 added meaningful predictor variables (based on available data) to the previously defined growth curves (Chapter 4) and identified both demographic and intervention-specific variables that were predictive of growth. Predictors varied by level of communicative function, a new insight in the field. This work has clinical implications both within and beyond the PSLP.
Chapter 6 discusses the clinical and research implications of this dissertation work as well as ideas for future directions of my research.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The work presented in this dissertation explored participation-based outcomes for preschoolers with communication disorders. First, by completing a scoping review, I identified the need to explore participation-based outcomes for preschoolers with communication disorders. Participation-based outcomes are important and meaningful for families, but are not typically used in speech-language research or practice. I next modelled the development of communicative participation skills (how a child uses his/her communication to engage) for preschoolers with speech and language delays who were accessing services in Ontario’s Preschool Speech and Language Program (PSLP). Following this I identified both demographic and intervention-based predictors of that communicative ‘growth’. Development was modelled separately for children in five levels of communicative function using a reliable classification tool that I validated for use with this general community-based population. This work addresses a major gap in the speech-language literature and has important implications for clinicians, administrators and policy makers in the PSLP and beyond.


title: Performance and Reaction Mechanisms of Solid Oxide Fuel Cell Cathodes Fabricated by the Impregnation Method

contributor:
Petric, Anthony
Materials Science and Engineering

subject: performance, mechanism, solid oxide, fuel cell, cathode, fabricated, impregnation method, polarization loss

abstract:
 The exploration of cathode materials and fabrication methods plays an important role in the development of solid oxide fuel cell (SOFC) technology. The objective of this study is first to optimize the cathode microstructure by the impregnation method, and then investigate the potential application of copper manganese spinel as a new cathode material with optimized microstructure and explore the reaction mechanism of the cathodes.

 The impregnation method was employed to fabricate a composite cathode with electrocatalyst particles dispersed in a framework of electrolyte material. The impregnation method is relatively easy to apply and yield the optimized microstructure, allowing extended three phase boundary length and absence of secondary phase formation during fabrication.

 The polarization performance of copper manganese spinel (CMO) impregnated YSZ cathodes was examined by adjusting catalyst particle size, electrode thickness and catalyst content. A critical thickness of 16.9±2.0 μm for the CMO-YSZ composite cathode was calculated from Tanner's model. Decreased catalyst particle size and a thickness close to the critical value were found to eliminate polarization loss. The composite cathode with 50 wt% CMO impregnation showed a polarization resistance as low as 0.3 Ωcm^2 at 750°C. At 800°C, an SOFC with CMO-YSZ composite cathode had a power density of 172 mW/cm^2, which was 2.5 times higher than the cell with the traditional LSM-YSZ composite cathode under the same conditions.

 The cathode reaction mechanism of CMO-YSZ and strontium doped lanthanum ferrite (LSCF) impregnated Gd doped ceria ( CGO) composite cathodes was studied, using impedance spectroscopy, cyclic voltammetry and current interruption
techniques. Surface diffusion and mass transfer were determined to be the rate controlling
steps for CMO-YSZ composite cathode at low and high temperatures, respectively. A low frequency process at low temperatures and at least two processes at high temperatures were identified as rate determining steps of LSCF -CGO composite cathodes. A cathodic current activation effect was observed on CMO-YSZ cathode under current passage. The catalytic activity of CMO was enhanced by the cathodic current and the effect existed in both long-term and short-term experiments.

 The results of this study suggest that copper manganese spinel has attractive properties as a new catalyst material for the cathodic reaction with the composite structure obtained by the impregnation method.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: REGULARIZATION OF THE BACKWARDS KURAMOTO-SIVASHINSKY EQUATION

contributor:
Protas, Bartosz
Computational Engineering and Science

subject: Kuramoto-sivashinsky Equation, retrograde data assimilation

abstract:
We are interested in backward-in-time solution techniques for evolutionary PDE problems
arising in fluid mechanics. In addition to their intrinsic interest, such techniques have
applications in recently proposed retrograde data assimilation. As our model system we
consider the terminal value problem for the Kuramoto-Sivashinsky equation in a l D periodic
domain. The Kuramoto-Sivashinsky equation, proposed as a model for interfacial
and combustion phenomena, is often also adopted as a toy model for hydrodynamic turbulence
because of its multiscale and chaotic dynamics. Such backward problems are typical
examples of ill-posed problems, where any disturbances are amplified exponentially during
the backward march. Hence, regularization is required to solve such problems efficiently in
practice. We consider regularization approaches in which the original ill-posed problem is
approximated with a less ill-posed problem, which is achieved by adding a regularization
term to the original equation. While such techniques are relatively well-understood for
linear problems, it is still unclear what effect these techniques may have in the nonlinear
setting. In addition to considering regularization terms with fixed magnitudes, we also
explore a novel approach in which these magnitudes are adapted dynamically using simple
concepts from the Control Theory.

abstract: Thesis

abstract: Master of Science (MSc)


title: THE FEASIBILITY OF THE SUSTAINABLE RE-DEVELOPMENT OF UNIVERSITY PLAZA

contributor:
Baetz, Brian
Churchill, Cameron
Engineering Design

subject: Re-development of University Plaza, Road Network Design and Parking

abstract:
This paper investigates the feasibility of the construction of a
sustainable mixed-use development from a 1950's commercial plaza. The
specific commercial plaza under investigation was University Plaza in
Dundas, Ontario. Incorporating sustainable building techniques, such as
higher density housing, clean energy generating technologies, energy
efficiency, and water conservation, a more sustainable design for the
plaza was accomplished. To become more pedestrian friendly, pedestrian
areas were incorporated into the design, as well as a rapid transit terminal.
Using rough construction estimates, it was determined that redevelopment
would cost $67.9 million± 20% with a simple payback period of 7.8 years.
Using the time value of money, a discounted payback period between 9.6
and 16.0 years was determined. As a result, the re-development project
was deemed economically feasible to a reasonable degree.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Lithium Niobate MEMS Device by Picosecond Laser Machining

subject: lithium niobate, MEMS device, picosecond, laser, machining, electro-optic effect, piezoelectricity, pulse

abstract:
 Lithium niobate has interesting characteristics such as the electro-optic effect, the acousto-optic effect, piezoelectricity and large nonlinear optical coefficients. Potential applications in MEMS field could be explored if microstructures are fabricated in lithium niobate substrates,. This thesis presents the fabrication and characterization of a lithium niobate MEMS device. As lithium niobate crystal is difficult to process using standard semiconductor techniques including both wet etching and dry etching, new methods are
required to process lithium niobate. In our project, picosecond laser pulses were chosen to
produce bridges on lithium niobate. Fabrication of grooves with high aspect ratio were attempted and grooves with clean morphology were obtained when laser pulses with low cutting speed, medium pulse energy, and large number of passes were employed. This shows picosecond laser machining is a viable method to process lithium niobate.

 Waveguides in Z cut lithium niobate crystal were fabricated using Ti-indiffusion techniques. After the fabrication of waveguides in lithium niobate, a SiO2 film with a thickness of 0.3μm was deposited as a buffer layer. Ti-Pt-Au electrodes for actuation function were then deposited through lift-off technique. Finally a bridge structure (80um in width and 600um in length) with a waveguide embedded in it was fabricated with picosecond laser. The insertion loss before and after laser machining was 6.99dB and 5.01dB respectively.

 Optical and electrical tests were performed in an effort to determine the resonance frequency of bridge. In the optical test, many bulk piezoelectric resonance peaks were presented in the frequency spectrum. After damping the vibration of substrate, these spikes disappeared and only a background noise with small spikes were obtained. As those small spikes are not reproducible, the optical test is not a viable method to determine resonance frequency of the bridge structure in our device. The electrical test was then carried out in a vacuum environment in order to find the resonance frequency. The spectrum presents a spike with large amplitude. However, the phase and amplitude of the spike remained the same when the vacuum condition was removed, which indicates the spike is not related to the resonance of the bridge. In summary, the resonance frequency of bridge structure could not be determined by these two approaches.

 Future work could involve directly investigating the material properties surrounding the machining region to see whether the piezoelectricity of the material has been damaged from laser ablation process. New laser machining process of lithium niobate may also need to be studied to avoid this damage to the substrate structure. Even though our device could not be driven to vibrate at its resonance frequency, it is worth making microstructures in lithium niobate substrates. The combination of optical, mechanical and electrical elements will make lithium niobate a great potential material for optical MEMS
applications.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Oriented 3D Printing

contributor:
Spence, Allan
Computational Engineering and Science

subject: oriented, 3D printing, coordinate measuring machine, ink jet, flat metal, glass samples

abstract: Ink-jet printing onto flat paper is a widely established process. In this thesis, we make extensions to printing on target surfaces such as metals and glass, using a 5-axis orientable head. Original artwork is created using CAD, and is sampled to create the ink jet point cloud. The target surface location is registered using a standard Coordinate Measuring Machine (CMM) 5-axis touch trigger probe. The probe is then replaced with the ink jet head and the printing process is carried out. Demonstration of the system is illustrated using flat metal and glass samples, as well as rapid prototyped 3-D plastic shapes.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: THE PRECLINICAL DEVELOPMENT OF ONCOLYTIC VIRAL IMMUNOTHERAPY FOR EPITHELIAL CANCER

contributor:
Lichty, Brian D
Medical Sciences

subject:
Oncolytic virus
MG1 Maraba
Epithelial cancer
Cancer immunotherapy

abstract:
HPV-associated cancer and carcinoma of the prostate are responsible for significant worldwide morbidity and mortality. The viral transforming proteins E6 and E7 make human papilloma virus positive (HPV+) malignancies an attractive target for cancer immunotherapy however, therapeutic vaccination exerts limited efficacy in the setting of advanced disease. In prostatic carcinoma therapeutic vaccination shows some therapeutic activity but is infrequently curative.

A strategy to induce substantial specific immune responses against multiple epitopes of E6 and E7 proteins based on an attenuated transgene from HPV serotypes 16 and 18, that is incorporated into MG1-Maraba virotherapy (MG1-E6E7), was designed. MG1-E6E7 is able to boost specific immunity following priming with either an adenoviral vector (Ad-E6E7) or customised synthetic peptide vaccines resulting in multifunctional CD8+ T cell responses of an enormous magnitude. MG1-E6E7 vaccination in the HPV+ murine model TC1 is curative against large tumours in a CD8+ dependent manner and results in durable immunologic memory. Using the same adenoviral prime and MG1 boosting strategy targeting the prostatic antigen, STEAP, immunity against multiple CD8+ STEAP epitopes was induced. In a murine prostate cancer model, STEAP specific oncolytic virotherapy significantly improved the survival of mice bearing advanced TRAMP-C2 tumours.

One significant obstacle to therapeutic cancer vaccination is an immunosuppressive tumour microenvironment. MG1 Maraba is able to lethally infect HPV-associated and prostate cancer cells, increase the immunologic activity within the tumour microenvironment in vivo and exploit molecular hallmarks of HPV-positive cancer and prostatic carcinoma enabling infection of bulky tumours.

Pre-clinical data generated within this thesis has been instrumental in securing funding for future clinical trials assessing the safety and activity of MG1 Maraba virotherapy for HPV-associated cancer and prostatic carcinoma. This promising approach has the potential to be directly translatable to human clinical oncology to tackle these two highly prevalent and frequently lethal groups of epithelial neoplasia.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Carcinoma (epithelial cancer) is the most common form of human cancer and two frequently encountered types, namely HPV-associated and prostatic carcinoma are responsible for a substantial worldwide cancer burden. Current therapeutic options show limited clinical benefit and/ or significant long-term side effects for advanced carcinomas, therefore new treatments are urgently required. Oncolytic viruses represent an exciting new form of anti-tumour immunotherapy capable of infecting and killing cancerous cells; here we present a virus called MG1 Maraba that is able to exploit molecular characteristics of these cancers. When MG1 Maraba is engineered to target proteins from HPV-associated cancer and prostatic carcinoma, specific immune attack against these tumours occur in mouse cancer models. MG1 Maraba offers a novel, selective, safe and highly promising therapeutic approach against advanced carcinomas. Based on the information within this thesis human clinical trials assessing MG1 Maraba are due to take place for both HPV-associated and prostate cancer.


title: Building 'a natural industry of this country': an environmental history of the Ontario cheese industry from the 1860s to the 1930s

title: An environmental history of the Ontario cheese industry

contributor:
Egan, Michael
History

subject:
cheese industry
Ontario
environmental history
dairying
alternative rural modernity
work
rural history

abstract: This dissertation examines the origins and development of the cheese industry in rural Ontario between the 1860s and 1930s from the perspective of environmental history. Scholars have generally accepted contemporary beliefs that cheese was a “natural industry of this country” and that its growth was cooperative and inevitable. This dissertation tests these claims by comparing the rhetoric and actions of the rural elite and state officials against the human and extra-human work involved in manufacturing cheese for export, a method that has yielded new interpretations about the character and development of the industry. I build on James Murton’s concept of “alternative rural modernity” to argue that rural cheese manufacturing was a project of rural reform encouraged by elite ‘dairy reformers,’ rather than a natural development. Reformers believed cheese factories could support the social, economic and environmental stability of rural society indefinitely. Through cheese, they sought to create a society that was liberal and capitalist, but also cooperative and stable. They also believed that dairying would restore fertility to the region’s soils. In practice, however, their results were mixed. Although cheese became one of the province’s most significant export-oriented industries, transformed the environment, and deepened liberal values amongst rural people, it failed to deliver the alternative rural modernity reformers had envisioned. I provide two reasons why. First, the reformers’ mechanistic vision could not contend with the complexity and unpredictability of the socio-ecological world they sought to control. Second, the industry could not withstand the pressures of the emerging global capitalist food system and, ironically, facilitated the rise of ‘Big Dairy’ after the First World War, which hastened the industry’s demise. Overall, this dissertation emphasizes the dynamism of rural Ontario, contributes to an environmental history of liberal order in Canada, and contextualizes the resurgence of craft-based rural development in the twenty-first century.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: This dissertation examines the origins and development of the factory cheese industry in rural Ontario between the 1860s and 1930s. I challenge the belief that cheese manufacturing was a “natural industry of this country” whose development was cooperative and inevitable. Instead I argue that the industry was a deliberate project of rural reform encouraged by elite ‘dairy reformers’ who believed cheese factories could sustain the social, economic, and environmental progress of rural society indefinitely. The industry failed to deliver all the reformers promised, even though it became one of the province’s most significant export-oriented industries by the early-twentieth century and transformed the environment and rural society in the process. Rural people and the environment behaved in more complicated ways than reformers anticipated, and the changing capitalist economy made the industry’s long-term success untenable. This study also contextualizes the twenty-first century resurgence of craft production in Ontario.


title: Modeling Film Boiling and Quenching on the Outer Surface of a Calandria Tube Following a Critical Break Loca in a CANDU Reactor

contributor:
Luxat, John C.
Engineering Physics

subject: moedling film, boiling, quenching, calandria tube, critical break loca, CANDU reactor, incident heat flux

abstract:
 In a postulated critical break LOCA in a CANDU reactor it is possible that heatup of a
pressure tube (PT) causes ballooning contact with the calandria tube (CT). Stored heat in the PT is transferred out, yielding a high PT-CT heat flux, which can cause dry out of the CT and establishment of pool film boiling on the outer surface of the tube. The safety concern associated with this condition is that if the temperature of the CT experiencing film boiling gets sufficiently high then failure of the fuel channel may occur. However, quench heat transfer can limit the extent and duration of film boiling as has been experimentally observed. Current estimates of quench temperatures during pool film boiling are based primarily on experimental correlations. In this dissertation a novel mechanistic model of pool film boiling on the outside of a horizontal tube with diameter relevant to CT (approximately 130 mm) has been developed. The model is based in part upon characterizing the vapor film thickness for steady state film boiling under buoyancy driven natural convection flows around a tube located horizontally in a large liquid pool. Variations in steady state vapor film thickness as a function of the incident heat flux, the temperature of the CT outer wall, and the subcooling of the bulk liquid are analyzed. The calculated effective film boiling heat transfer coefficient is compared to available experimental data. Finally a transient equation is developed which quantifies the instability of the vapor film and a possible occurrence of rapid quench when a step change in governing parameters occurs, such as liquid subcooling. This mechanistic
model can be employed in safety analysis to demarcate the conditions under which fuel
channel failure will not occur in a postulated critical break LOCA.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Examining Community Capacity and Resilience Post-Outbreak in Walkerton, Ontario

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
Walkerton
qualitative
community resilience
life course
long-term
capacity

abstract:
Most disaster management studies only assess community resilience immediately following the event with no further follow-up. Accordingly, there is a lack of research being conducted to determine whether communities truly recover over time after a disaster strikes. Thus, the purpose of this research was to examine the different factors and dimensions that facilitate or hinder community resilience more than a decade post-disaster using present day Walkerton, Ontario (16 years after the effects of the 2000 water contamination outbreak).
This exploratory study utilized an interpretive description qualitative methodology. Semi-structured interviews and focus groups were conducted with a purposeful sample of 29 Walkerton community members. The data were transcribed verbatim and coded using conventional content analysis to identify themes inductively. Several barriers and enabling factors were identified in maintaining community resilience under non-crisis conditions in the community. A conceptual model was developed based on the study’s findings to demonstrate the application of the life course approach within an existing community resilience framework. This model contributes to the field of disaster management in demonstrating the various ways that a disaster affects the subsequent life course of individuals post-disaster. It highlights the need to integrate a community-centred approach in disaster management to yield more effective and efficient mitigation, preparation, response, and recovery strategies.

abstract: Thesis

abstract: Master of Public Health (MPH)


title: THYMIC STROMAL LYMPHOPOIETIN: THE FUNCTIONAL IMPLICATIONS OF THE TSLP GENE POLYMORPHISM RS1837253 IN ALLERGIC ASTHMA

contributor:
Denburg, Judah
Medical Sciences

abstract: Thymic stromal lymphopoietin (TSLP) is a regulator of Th2 immune responses and is highly implicated in the pathophysiology of asthma and allergic diseases. Although robust data is present referencing the associations of polymorphisms in the TSLP gene with the development of allergy and asthma, there is very limited information on how TSLP gene variants functionally affect downstream effector pathways with regards to disease phenotypes in the clinical setting. The overall objective of this thesis is to investigate how TSLP polymorphisms are linked to the clinical phenotypic differences including alterations in TSLP secretion and subsequent downstream cellular events. We show that polyinosinic:polycytidylic acid (polyI:C) enhanced TSLP secretion from nasal epithelial cells (NEC). To explore the potential regulatory mechanisms acting on a key variant of the TSLP gene, we investigated associations between the rs1837253 TSLP variant and transcriptional regulatory factors RIG-1 and AP-1, finding no association between levels of expression of these regulators and genotype. We also investigated ex vivo production of TSLP and downstream cytokines in nasal epithelial cells (NEC) in asthmatic and non-asthmatic individuals to outline variances in expression according to disease status and genotype. We showed that NEC derived from asthmatic individuals showed significant differences in expression in asthmatic compared to non-asthmatic individuals. Furthermore, we demonstrated that there was a difference in the expression of TSLP in the asthmatic subpopulation compared to non-asthmatics when categorized by genotype, suggesting an altered regulatory mechanism of TSLP secretion for asthmatic compared to non-asthmatic individuals.

abstract: Thesis

abstract: Master of Science (MSc)


title: Interferometric Photonic Sensors in Silicon-On-Insulator Waveguides

contributor:
Jessop, Paul E.
Engineering Physics

subject: interferometric, photonic, sensors, silicon, insulator, waveguides, Mach-Zehnder

abstract:
 An optical temperature sensor and Fourier spectrometer, working in the 1550nm telecommunications wavelength range, were fabricated in silicon-on-insulator. Both devices were based on asymmetric Mach-Zehnder Interferometer waveguide geometries. The temperature sensor underwent a two phase design. The various asymmetry factors, due to different path length differences, of the Mach-Zehnder arms resulted in different levels of temperature sensitivity, which in turn was the driving mechanism behind the Fourier
spectrometer. Due to the asymmetry of the Mach-Zehnder arms, there exists an inherent optical path length difference which is further changed with temperature variation due to the thermo-optic effect. The phase I temperature sensor showed an accuracy of 1-2°C and a sensitivity of 0.5°C for ΔL of 37.23μm and 23.46μm, respectively. The phase II temperature sensor design, which allowed for self normalization, resulted in a 1°C temperature accuracy and a 0.5°C sensitivity for a ΔL of 27.85μm. Both the phase I and II temperature sensors showed repeatable and stable results for the temperature range of 20-100°C, and agreed well with the theoretical design performance. Upon analysis of the highly asymmetric Mach-Zehnder designs it was found that both the 1.05cm and 3.05cm path length differences resulted in a temperature accuracy of 0.1°C, with a 0.05°C sensitivity over a small temperature range.

 The Fourier spectrometer exhibited decent agreeability with theoretical design performance and demonstrated proof of concept. A 1.05cm path length difference was insufficient to resolve two wavelengths at 1546.12nm and 1564.68nm, which agreed with the theoretical model. However, the 3.05cm ΔL was sufficient to resolve the two wavelengths in a repeatable manner.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Ion Implanted Bragg Gratings in Silicon-On-Insulator Rib Waveguides

contributor:
Jessop, P.E.
Engineering Physics

subject: ion, implanted bragg gratings, silicon, insulator, rib waveguides

abstract:
 Ion implanted Bragg gratings integrated in rib waveguide structures were simulated,
fabricated and characterized for the silicon-on-insulator (SOI) photonics platform. After
selective silicon self-implantation, to an amorphizing dose of 2x10^15 ions/cm^2, the
approximately 0.3 damage-induced increase in the refractive index provided the modulation mechanism necessary for the formation of a Bragg grating. The benefits of implanted Bragg gratings compared to the more widely utilized surface relief type gratings include planar surface retention, desirable for subsequent processing and wafer bonding, and a smaller depth of the index modulation, important for minimizing filtering bandwidths. To our knowledge, this is the first time ion implantation has been utilized to produce Bragg gratings integrated in an SOI rib waveguide. The benefits of using SOI for an optoelectronics platform include: cost minimization, reduced device size, and compatibility with silicon based microelectronics.

 Device performance was simulated using coupled mode theory (CMT) in conjunction with beam propagation methods (BPM), to determine transverse modal
profiles for computing coupling coefficients and to determine geometric dimensions suitable to achieve adequate grating strength and single-mode operation. The Monte Carlo ion implantation simulator SUSPREM4, implementing the binary collision approximation (BCA), was used to determine the amorphous silicon grating profiles. Implanted grating devices were then fabricated into SOI having a 2.5 μm device layer and were optically characterized. For a grating length of 2100 μm and an implant energy of 60 keV, the extinction ratio of the resonant wavelength was found to be -18.11 dB and -0.87 dB for TE and TM polarizations respectively. The excess loss per unit length was measured to be 1.2 dB/mm for TE polarization and 0.6 dB/mm for TM polarization. After annealing the gratings at temperatures of up to 300 °C, used to annihilate low energy point defects responsible for absorption, it was found that the excess loss per unit length was reduced to 0.3 dB/mm for TE polarization. Compared to etched gratings with similar dimensions, it was determined that the strength of the implanted gratings was approximately 2.5 times stronger for grating lengths one third the length as result of mode-shifting due to the higher index of refraction. This is of great consequence to the miniaturization and densification of Bragg grating based devices in silicon photonics.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Contractile Properties of the Soleus, Tibialis Anterior and Thenar Muscles In Individuals With Spinanl Cord Injury

contributor:
Hicks, Audrey
Kinesiology

subject: Thenor Muscles in individuals, spinal cord injury, assessment of PTP

abstract:
To examine the effects of purported fiber-type transformation following spinal cord injury (SCI), twitch contractile properties of the soleus, tibialis anterior (TA) and thenar muscles were examined in individuals with chronic (> 4 years) SCI. Furthermore, the force-frequency relationship, fatigue and posttetanic potentiation (PTP) of the paralyzed TA muscle were also evaluated. Nine adults with SCI (22-59 yrs; lesion level C3-T2) and 9 age-and gender-matched able-bodied controls (AB) participated in this study.

On the first visit to the laboratory, the maximum twitch response for all three muscles was determined by delivering a series of single stimuli with gradually increasing intensity. For evaluation of PTP, tetanic stimulation (100Hz) was applied to the TA for 5 seconds followed by single twitches delivered at 5 seconds after tetanus and then at 30-second intervals for 4 minutes posttetanus. On a second visit, the force-frequency relationship (FFR) and 15Hz fatigue of the TA was evaluated. One second bursts ranging from 1-1OOHz were delivered randomly with 2 minutes of rest in between each frequency for assessment of FFR. Following a 1 0-minute rest period, the first fatigue protocol was given, consisting of 1-minute of tetanic stimulation at 15Hz. At the third session, the 30Hz fatigue of the TA was performed, consisting of 1-minute of tetanic stimulation at 30Hz.

In the soleus muscle, the AB had a higher peak twitch torque (PT) and M-wave  amplitude compared to.the SCI group (14.2 ± 3.9Nm vs. 8.9 ± 6.1Nm; p = 0.058, and
13.5 ± 5.3mV and 5.5 ± 4.0mV; p < 0.05, respectively). Contractile speed was not significantly different between groups. Time to peak torque (TPT) was longer in AB
(111.5 ± 15.4ms) compared to the SCI (76.7 ± 25.0ms; p<0.05) due to the larger twitches; however, the rates of torque development (RTD) were similar between groups. In the TA muscle, AB and SCI had similar PT (2.8 ± 0.5Nm and 3.2 ± 1.2Nm, respectively). TA contractile properties were faster in SCI, as seen by significantly shorter TPT and faster RTD (p<0.05). M-wave amplitude of AB was significantly greater than the SCI group,
8.3 ± 2.6mV versus 4.2 ± 1.7mV, respectively (p<0.05). Finally, in the thenar muscle, PT appeared to be smaller in AB compared to SCI, 1.7 ± 0.8Nm versus 2.9 ± 1.3Nm, respectively (p = 0.094). The RTD was faster in the SCI group compared to AB (p<0.05).

Evaluation of FFR revealed that the curve of the SCI was shifted to the left of that of AB. The F50 (frequency required to elicit 50% of maximum peak torque) was significantly lower in the SCI compared to AB, 6.7 ± 3.4Hz and 16.7 ± 4.1Hz, respectively (p<0.05). Following the fatigue protocols, SCI group tended to fatigue more rapidly and to a greater extent than AB at both frequencies, however this was only significant at 15Hz. The M-wave declined with fatigue (30Hz) in both groups, but this decline tended to be more rapid in SCI.

For the assessment of PTP, both groups started off with similar baseline twitches in their TA muscle (2.7 ± 0.3Nm and 2.9 ± 0.8Nm, respectively). At 5 seconds following tetanus, PT was significantly greater in both groups, but the amount of potentiation was greater in SCI versus AB (p = 0.058). Over the 4-min recovery period, PT declined in both groups until it was no longer significantly greater than baseline by 3 minutes 30 seconds. The potentiated twitch of both groups was faster than at baseline. RTD increased significantly by an average of 56% in the AB group and 91% in the SCI group and was significantly greater in SCI compared with AB at 30-150 seconds post-tetanus (p<0.05). At 5 seconds post-tetanus, RTR was significantly faster in both groups and had increased by 77% and 53% in the AB and SCI groups, respectively. The recovery ofRTD and R TR over the 4 minutes occurred more rapidly in AB versus SCI.

In conclusion, changes in contractile properties following SCI differ between muscle groups; faster contractile properties indicative of fiber type transformation are more evident in TA and thenar muscle groups, compared with the soleus. The smaller M-waves seen in the lower extremities support the significant muscle atrophy following SCI. Furthermore, the predicted transformation towards a higher proportion of fast-twitch fibers following paralysis was supported by a trend for decreased fatigue resistance and significantly greater PTP in the SCI group. The FFR data, however, did not support this predicted fiber type transformation, shifting to the left instead of the right. This leftward shift of FFR has been reported in other paralyzed human muscle presenting with faster contractile speeds; the mechanisms behind this warrant further investigation.

abstract: Thesis

abstract: Master of Science (MSc)


title: Correlating Concrete Mix Design to Rheological Properties of Fresh Concrete

contributor:
Chidiac, Samir E.
Civil Engineering

subject: concrete, mix design, rheological properties, water content, cement, yield stress, plastic viscosity

abstract:
Workability has traditionally been used as one of the measures for controlling concrete
mixture proportioning. This metric has provided limits on the water content in the concrete mixture for given aggregate size and type. The slump test, which is commonly used as an assessment of workability, is not adequate for characterizing the flow behaviour / rheology of fresh concrete. Studies have shown that Bingham's rheological properties, namely yield stress and plastic viscosity, provide good description of the flow behaviour of fresh concrete. In this thesis, an experimental program was designed on the basis of factorial design to evaluate the method of Cement Association of Canada for designing and controlling concrete mixture. The variables included in the mix design are water-cement ratio, water content, coarse aggregate size, silica fume, slag and bulk volume of coarse aggregate. In addition, Neuro-Fuzzy network
has been adopted to correlate the current mixture proportioning method to the rheological
properties of concrete. The network was constructed using experimental data tested in this study. Such correlation allowed the determination of water-cement ratio, water content, fine aggregate and coarse aggregate from compressive strength, yield stress and plastic viscosity.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Incompatibilists, Critics, and Living Trees: the compatibility of international law and constitutional democracy

contributor:
Waluchow, Wil
Philosophy

subject: Philosophy of Law; Constitutional Democracy; International Law; Judicial Review

abstract: In this thesis, I address two issues. First, I reject the supposed conflict between international law and constitutional democracy. And second, I explore the role of international law in domestic constitutional law, particularly in Canada. In order to address both of these issues, I draw an analogy between the “Incompatibilist” critiques of international law and constitutional democracy, and the arguments against judicial review made by “the Critics” that Waluchow responds to in his book, A Common Law Theory of Judicial Review: the Living Tree. I argue that both the Incompatibilists and the Critics describe in-principle problems, structural problems, and decision-making problems in their respective critiques. The Incompatibilists are describing these problems in the context of the interaction between international law and constitutional democracies, while the Critics are focusing on constitutional judicial review, but I argue that the theory Waluchow presents as an answer to the Critics can also be directly applied to the Incompatibilists. Waluchow’s theory of common law judicial review and the community’s constitutional morality gives support and democratic legitimacy to judicial review in a domestic constitutional context. By applying his reasoning to cases involving international norms, I address problems in domestic courts’ application of international law and the democratic challenges they face.

abstract: Thesis

abstract: Master of Arts (MA)


title: Agreement Variation in English Existential Constructions

contributor:
Kučerová, Ivona
Cognitive Science of Language

abstract:
This thesis focuses on providing an account of the variation in agreement in English existential
constructions of the form There-BE-plural NP. Copular agreement in these constructions can be either singular or plural. Unlike most English sentences, which show verbal agreement with the syntactic subject (the element in Spec, TP), standard agreement in these constructions is assumed to show number agreement with the plural, post-copular NP. Though many English speakers prefer the plural agreement, the full and abbreviated singular is attested and must be accounted for. This thesis aims to provide a syntactic and semantic account of the agreement patterns within these constructions. Semantic conclusions are drawn from a semantic judgment survey which investigated the effect of agreement type on NP interpretation. The syntactic account mainly draws on the notion that number agreement is the result of an NP moving before the verb at some point in the derivation (Kayne 2011), and the parallels between English existentials and Icelandic constructions involving long-distance agreement (Kučerová 2016).

abstract: Thesis

abstract: Master of Science (MSc)


title: Development of A Probabilistic Channel Flood Routing Method For Stormwater Management Analysis

contributor:
Guo, Y.
Civil Engineering

subject: Stormwater models, Muskingum routing method,

abstract: An approach to incorporate the effect of flood routing through a channel reach for use with the analytical probabilistic stormwater models (APSWM) was developed earlier in 2005. That earlier approach relied on adding the Muskingum K value of the channel reach into the catchment time of concentration and treating the whole drainage area including the channel reach as a lumped catchment. This is insufficient since other factors such as the X value in the Muskingum routing method also affects the routing results. In this study, a new approach to incorporate the routing effect of channel reaches in APSWM was developed where not only the K value but also the X value of a channel reach are considered. A number of continuous simulations were conducted to verify the proposed approach. It was demonstrated that the proposed approach performs better than the earlier one.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Theory of Binary Mixtures of Diblock Copolymers: A New Route to the Double-Diamond & Plumber’s Nightmare Phases

contributor:
Shi, An-Chang
Physics and Astronomy

subject:
Polymers
Self-assembly
Bicontinuous phases
Binary mixtures

abstract: We study the formation of novel bicontinuous phases in binary mixtures of AB diblock copolymers (DBCP) using the polymeric self-consistent field theory. We predict that the bicontinuous double-diamond (DD) and plumber’s nightmare (P) phases, which are metastable phases of neat diblock copolymers, could be stablized in gyroid-forming A-minority DBCPs via the blending of specifically designed A-majority DBCPs. The mechanisms of stabilizing different bicontinuous phases are revealed by analyzing the spatial distribution of the different DBCPs. It is found that the A-majority DBCPs residing mainly in the nodes of the structure, thus alleviating the packing frustration of the A-blocks. Furthermore, a local segregation of the two DBCPs occurs at the AB interface, thus regulating the local curvature of the interfaces. A synergetic interplay of these two mechanisms results in a larger stable region of the DD and P phases via the addition of tailored A-majority DBCPs. The theoretical study provides an efficient route to obtain novel bicontinuous phases.

abstract: Thesis

abstract: Master of Science (MSc)


title: Microbiota induced immune system maturation plays a key role in development of normal behaviour

contributor:
Bercik, Premysl
Medical Sciences

subject: Intestinal microbiota, behaviour, Innate immune system, nervous system

abstract:
Gut microbiota has been shown to regulate the growth and development of the central and enteric nervous systems (CNS and ENS) after birth. There is ample evidence to suggest that intestinal bacteria can influence behavior of the host through both immune and immune-independent mechanisms. Gut-microbiota-regulated CNS structural changes are focused in the limbic system, at centres associated with memory, social and emotional behaviour. Several studies using germ-free (GF) and specific pathogen free (SPF) mice demonstrated microbial influence on behaviour development accompanied by neurochemical changes in the brain. Higher exploratory and lower anxiety-like behavior was found in GF mice compared to SPF mice with lower central expression of neurotrophins, such as nerve growth factor and BDNF. The mechanisms by which the microbiota influences behavior are unknown but could be immune-mediated, neural, or humoral in origin.
In this study I investigated the role of immune system maturation on mouse behaviour after bacterial colonization. I showed that mono-colonization of GF mice with E. coli normalizes behaviour similar to colonization with complex microbiota (SPF and ASF) and the continuous presence of bacteria is not required to maintain this normal behaviour. I also showed that innate immunity through the MyD88/Ticam pathway is crucial for the development of normal behaviour and that multiple innate immunity and neuronal genes are involved in this process. Together these results suggest that bacterial colonization primes and matures the innate immunity and development of the central nervous system ultimately leading to normal behaviour. I believe that bacterial colonization at birth is not only important for the epithelial barrier function, gut homeostasis, and immune functions, but also for the development of normal behaviour. Altered immune priming during the postnatal period due to abnormal microbial colonization may have wider implications when considering psychiatric disorders in humans.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)