title: Evaluation of a Novel Aero-Engine Nose Cone Anti-Icing System Using a Rotating Heat Pipe

contributor:
Ewing, Daniel
Ching, Chan
Mechanical Engineering

subject:
aero-engine
anti-icing
heat pipe
rotating heat pipe

abstract: Preventing ice accumulation on aircraft surfaces is important to maintain safe operation during flight. Ice accumulation on aero-engine nose cones is detrimental as large pieces may break off and be ingested into the engine damaging the compressor blades. Currently, hot bleed air is taken from the compressor and blown over the inside and outside surfaces of the nose cone to prevent ice formation on the surface. Although effective, this technique reduces the efficiency of the aero-engine. This investigation evaluates the performance of a novel anti-icing system that uses a rotating heat pipe to transfer heat from the engine to the nose cone. Rotating heat pipes are effective two-phase heat transfer devices capable of transporting large amounts of heat over small temperature differences and cross-sectional areas. In this system, waste heat that is generated in the engine would be transferred to the rotating heat pipe at an evaporator and then transferred into the critical areas of the nose cone at a condenser preventing ice accumulation on the outside surface. In this investigation, the heat is transferred into the heat pipe from a fluid heated by the engine that would pass through a small annular gap between the rotating heat pipe and a stationary wall. The heat transfer for this configuration and the effect of passive heat transfer augmentation on the outside of the rotating heat pipe in the jacket was investigated experimentally for a range of Taylor numbers of 10^6 < Ta < 5x10^7 and for axial Reynolds numbers of 900 < Re_x < 2100, characteristic of this configuration when engine lubricant was used as the working fluid. It was found that by using an array of three-dimensional cubical protrusions, the heat transfer in the evaporator could be increased by 35% to 100%. This result was better than that found using two-dimensional rib roughness. It was also found that the evaporator performance was a limiting factor in the heat transfer performance of the system under most conditions, so further optimization of the evaporator is important. In the proposed condenser design, the condenser section of the rotating heat pipe would be encased in a lightweight, high conductivity polycrystalline graphite or similar composite material and the end of the heat pipe would be in direct contact with the nose cone. It was found that the end-wall of the heat pipe was not a source of high heat transfer, however it provided an effective means for heating the tip of the nose cone. The effect of using heating channels on the inside of the nose cone was also considered. Here, the condensate from the rotating heat pipe was driven through small radially spaced channels on the inside surface of the nose cone. The heating channels were found to be ineffective due to the small contact area that could be made with the nose cone. This was a result of the limited condensate flow that occurs in rotating heat pipes. The heat transfer through the proposed system was 700W to 1100W using water and 400W to 800W using ethanol in the heat pipe. It was found that 50% to 75% of the arclength of the nose cone could be maintained above 0°C using water in the heat pipe at an ambient temperature of -30°C and an airplane speed of 300 km/h. This arclength decreased to approximately 25% when ethanol was used as the working fluid. An increase in airplane speed reduced this arclength maintained above 0°C significantly.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Modeling Si/Ge Interdiffusion in Si/Si_1-xGe_x/Si Single Quantum Well Structures

contributor:
Haddara, Yaser
Electrical Engineering

subject:
modeling
Si/Ge
interdiffusion
quantum
quantum well structure

abstract: Recently Silicon Germanium alloy (Si_1-xGe_x) is showing lots of potentials in device fabrication. Most of the structures containing Si_1-xGe_x that are fabricated at present involve Si/Si_1-xGe_x heterostructure. The fabrication process involves several high temperature anneal steps in either inert, oxidizing or nitriding ambient which results the interdiffusion of Si and Ge through the hetero-interfaces. The interdiffusion causes broadening of Si/Si1_xGex interface and changes the physical position of the heterointerface which can cause degradation of device performance. Several studies have so far been done to quantify the amount of Ge interdiffusion in heterostructures. However no study has yet been performed to model this phenomenon. Modeling the interdiffusion mechanism is important for two reasons: (1) it will facilitate to calibrate the device characteristics taking the effect of interdiffusion mechanism into calculations prior to device fabrication; and (2) to get a better insight of the actual mechanism involved in the interdiffusion process. In this study, attempt has been taken to model interdiffusion of Si and Ge in structures having Si/Si_1-xGe_x hetero-interfaces. Mathematical models are proposed to model the behavior and the models are applied to previously published results where samples were annealing in inert, oxidizing and nitriding ambient at different anneal temperatures for different anneal times. First only the contributions of vacancies in the interdiffusion mechanism are considered. This can successfully model the interdiffusion mechanism for samples annealed in inert and oxidizing ambients at low temperatures (below 1050°C). Next the contributions of interstitials along with vacancy in the interdiffusion mechanism are considered. These are able to successfully model the interdiffusion phenomenon for the samples annealed in oxidizing and nitriding ambients at high temperatures (above 1050°C). The success of the modeling is justified by getting good match between the simulated and the experimental interdiffusion profiles along with good match between the fitting parameters used in the simulations compared with previous reported values. Besides modeling the interdiffusion mechanism, for the first time, a mathematical model is proposed for vacancy injection while nitridation of silicon is done.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Realization of a Cognitive Radio-Mesh Network Based on OFDMA Technology

contributor:
Haykin, Simon
Electrical and Computer Engineering

subject: cognitive radio-mesh OFDMA technology

abstract: The goal of this thesis is to realize some critical techniques required in the cognitive radio mesh network. Cognitive radio (CR) is a new technology introduced to improve the frequency efficiency of current wireless systems. A mesh network, which leverages the advantages of an infrastructure network and a pure ad-hoc network, is a network topology highly suitable for the CR networks. CR users need to adapt to their ambient wireless environment and automatically select their own effective transceiver mode. The thesis focuses on the realization of a physical layer protocol, dynamic frequency-selection algorithm, mesh network signalling method, and transmit-power control algorithm in CR mesh networks. A new dynamic frequency selection algorithm is introduced in CR network, including estimation of the primary users' traffic statistics as well as adaptation to the local background noise interference. Through continuous observation, analysis, and adaptation to the time-varying environment, CR is able to select the candidate frequency bands to satisfy a user's rate and power requirements without causing collision to the primary users in those bands. As a generic model, a Gaussian mixture model, is selected for characterizing the statistics of the traffic environment. The transmit-power control in the CR mesh network is based on an iterative water-filling algorithm, rooted in information theory. The iterative water-filling algorithm is modified to suit the requirement of CR mesh networks. It works well for setting a suitable transmit-power level, sub-channels, and sub-carriers for the nodes in a CR mesh network. To support current systems, experiments are presented on the wireless mesh network, which are based on the orthogonal frequency-division multiple-access (OFDMA) mode of the High-speed Unlicensed Wireless Metropolitan Area Network (Wireless HUMAN). In the mesh network, the multiple access control(MAC) layer signals including the distributed network configuration, network entry, and network scheduling signals, are introduced. They are transmitted through a control channel in a cooperative mechanism. The physical layer(PHY) of OFDMA is also discussed in the thesis.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: THE EFFECTIVENESS AND SAFETY OF TREATMENTS USED FOR THE MANAGEMENT OF PATENT DUCTUS ARTERIOSUS (PDA) IN PRETERM INFANTS: A SYSTEMATIC REVIEW AND NETWORK META-ANALYSIS

title: TREATMENT OF PATENT DUCTUS ARTERIOSUS IN PRETERM INFANT

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
preterm
patent ductus arteriosus
systematic review
network meta-analysis

abstract:
OBJECTIVES: The objective of this thesis is to explore the effectiveness and safety of common pharmacotherapeutic options used for the management of patent ductus arteriosus (PDA) in preterm infants.
METHODS: Following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidance, article 1 develops the protocol to conduct the systematic review and network meta-analysis to answer the research question. Article 2 details the actual methods implemented to conduct the network meta-analysis and presents the results in the form of network plots, league tables, rank heat maps, rankograms and forest plots.
RESULTS: Article 1 suggests the need to conduct a Bayesian random-effects network meta-analysis of randomized controlled trials (RCTs) as the analysis would involve multiple treatments with potentially both direct and indirect comparisons. Article 1 also a priori defines potential effect modifiers and statistical strategies to control for the same. In article 2, the results of the meta-analysis show that in 68 RCTs that included 4802 infants, 14 different variations of indomethacin, ibuprofen or acetaminophen were used. Oral high-dose ibuprofen was associated with a significantly higher odds of PDA closure compared with standard-dose intravenous ibuprofen (Odds Ratio [OR], 3.59; 95% Credible Interval [CrI],1.64-8.17) and intravenous indomethacin (OR, 2.35; 95% CrI,1.08-5.31). Oral high-dose ibuprofen ranked the best option for PDA closure (SUCRA [surface under the cumulative ranking curve],0.89 [SD, 0.12]) and to prevent surgical PDA ligation (SUCRA,0.98 [SD, 0.08]). There was no significant difference in the odds of mortality, necrotizing enterocolitis or intra-ventricular hemorrhage with use of placebo or no treatment compared with any of the other treatment modalities.
CONCLUSION: This thesis suggests that oral high-dose ibuprofen could be the best treatment option for closure of a hemodynamically significant PDA. Placebo or no treatment for a hemodynamically significant PDA may not increase morbidity and mortality.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The following thesis explores the effectiveness and safety of commonly used drugs for the treatment of a heart condition in premature infants called the patent ductus arteriosus (PDA). Article 1 outlines the protocol for the systematic review and network meta-analysis designed to evaluate the effectiveness and safety of indomethacin, ibuprofen and acetaminophen for the treatment of PDA in preterm infants. Article 2 provides in detail the results of the network meta-analysis that examined all eligible randomized controlled trials that compared intravenous or oral formulations of indomethacin, ibuprofen or acetaminophen compared against to other or placebo for the treatment of a PDA that may be harmful for a premature infant based on certain clinical and echocardiographic criteria set by the clinicians and researchers. Overall, this body of work suggests that a higher dose of oral ibuprofen is the best treatment for PDA in premature infants.


title: Proactive immunity: commensal bacteria interact with the immune system to fight Pseudomonas aeruginosa

contributor:
Surette, Michael
Biochemistry and Biomedical Sciences

subject:
microbiome
immune system

abstract:
Multi-drug resistant Pseudomonas aeruginosa has become an increasing threat. A threat compounded by the fact that the pipeline of antimicrobial discovery continues to lose effectiveness. It is urgent that we identify new strategies to eliminate this and other multi-drug resistant pathogens. Meanwhile, we know that the resident bacteria of the respiratory tract interact with host cells to eliminate incoming threats.
The goal of this project is to understand the interactions at play in the microbiota of the respiratory tract and identify the specific commensal bacteria that inhibit P. aeruginosa in the presence of host cells.
Using a nasopharyngeal cell culture screen, we were able to identify several human commensals capable of inhibiting the growth of antibiotic-resistant P. aeruginosa in a host-dependent manner. It was also established that this phenotype can be reproduced in more complex systems, including a murine lung slice model, and that the elimination of the pathogen is dependent on the presence of living bacteria, mediated by a secreted factor.
We believe that the presence of these commensals has an immunomodulatory effect on the host. By characterizing the cytokines and chemokines produced by the host cells in response to the presence of these commensals, we have shown that these bacteria modify the immune response of the host to the pathogen.
Finally, having failed to develop a mouse model of infection, we have determined that the observed phenotype is not a direct action of the host cells, nor the result of hydrogen peroxide secretion. We have further characterized the bacterial strains using genome assembly.
This study has confirmed that commensal bacteria create a unique immune environment that contributes to the clearance of pathogens. Identifying bacteria and bacterial products capable of stimulating host defenses and modulating inflammation could provide a new therapeutic approach to reducing infection susceptibility in high-risk patients.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Antibiotics have for decades facilitated the cure of infections caused by pathogens of all kinds. Unfortunately, repeated exposure to antibiotics has rendered some pathogens highly resistant to traditional treatment. One notorious multi-drug resistant pathogen is Pseudomonas aeruginosa, now responsible for 10-15% of hospital-acquired respiratory infections. In this project we investigate the potential that lies in using commensal bacteria that exist in the microbiota of our respiratory tract to fight against pathogens that no longer respond to antibiotics. Stringent experiments with various models have revealed bacteria capable of killing Pseudomonas aeruginosa and helped us understand the mechanism of inhibition as well as the interactions of the bacteria with the immune system. Our results show that some bacteria of the microbiota are effective against Pseudomonas aeruginosa and that this line of study holds promise for the development of a new arsenal against a growing number of threatening pathogens.


title: Sequential Monte Carlo Methods and Their Applications

contributor:
Reilly, James
Kirubarajan, Thia
Electrical and Computer Engineering

subject:
monte carlo
sequential
application

abstract:
In recent years, the sequential Monte Carlo method, also referred to as the particle filter has emerged as a powerful methodology for solving the generally difficult nonlinear, non-Gaussian optimal filtering problem. The underlying idea is to use a randomly weighted set of samples to recursively build in time, a point-mass approximation of the true posterior PDF. With this approximation, one can recursively estimate typically intractable posterior expectations of interest. Indeed, the PF can be applied to a very large class of models. Within the last few years, the aforementioned advantages have propelled research on particle filtering and its applications. The subject of this thesis is to the extend the theories and applications of the particle filter. The main contributions of this thesis are described as follows: 1. We consider the optimal filtering problem for a class of partially observed non-Gaussian dynamic state space models. In this class, the process equation consists of a combination of linear and nonlinear states, and the process noise for the nonlinear state update is a mixture of Gaussians. In order to solve this problem, we propose a novel method based on an efficient combination of the approximate conditional mean filter and the sequential importance sampling particle filter.
2. We address the problem of channel equalization and phase noise suppression in orthogonal frequency division multiplexing (OFDM) systems. For OFDM systems, random phase noise introduced by the local oscillator causes two effects: the common phase error (CPE), and the intercarrier interference (ICI). The performance of coherent OFDM systems greatly depends on the ability to accurately estimate the effective dynamic channel i.e., the combined effect of the CPE and the time-varying frequency selective channel. With this in mind, we propose an algorithm that equalizes in the frequency domain, and uses a pilot tone aided particle filter to track/estimate the effective dynamic channel in the time domain. To increase efficiency, we implement the particle filter via a combination of sequential importance sampling, Rao-Blackwellization, and strategies stemming from the auxiliary particle filter.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Upstream Sequences Involved in Regulating the Candida tropicalis Gene Encoding Peroxisomal Trifunctional Enzyme

title: Regulation of Hydratase-Dehydrogenase-Epimerase

contributor:
Rachubinski, R. A.
Biochemistry

subject:
candida tropicalis
gene
peroxisome
yeast
enzyme

abstract:
We have inestigated the expression of the genes hydratase-dehydrogenase-epimerase (HDE), acyl-CoA oxidase (AOX) and catalase (CATL) of the diploid yeast Candida tropicalis. These genes encode enzymes which are localized to the peroxisome. Expression of each gene was monitored by immunoblot analysis of yeast lysates using antibodies directed against each protein. We demonstrate that carbon sources influence expression of these genes, and do so in a coordinate fashion.
We expressed C. tropicalis HDE in Saccharomyces cerevisiae and demonstrate that this trifunctional enzyme can be regulated by S. cerevisiae in a fashion that closely resembles that of C. tropicalis.
Expression of constructs containing deletions in the upstream region of the HDE gene allowed us to localize regions responsible for regulating the expression of this gene. Regions were identified that are responsible for both repression by glucose and induction by oleic acid. A glucoseresponsive region lies between nucleotides -466 and -334. An oleic acid-responsive region lies between nucleotides -333 and -281. An additional region controlling derepression by nonfermentable carbon sources is located downstream of nucleotide -281. Comparison of the upstream nucleotide sequences of HDE, AOX and CATL both to each other, and to upstream regions of other oleic acid-responsive genes of C. tropicalis has identified possible consensus nucleotide sequences for glucose-and oleic acid-responsive upstream elements. Since the regulation of the HDE gene in S. cerevisiae closely resembles that of C. tropicalis, this implies that similar mechanisms of transcriptional control operate in both yeasts.

abstract: Thesis

abstract: Master of Science (MS)


title: Air Pollution Modelling and Forecasting in Hamilton Using Data-Driven Methods

contributor:
Coulibaly, Paulin
Kanaroglou, Pavlos
Civil Engineering

subject:
air pollution
forecasting
hamilton
data-driven method

abstract: The purpose of this research is to provide an extensive evaluation of neural network models for the prediction and the simulation of some key air pollutants in Hamilton, Ontario, Canada. Hamilton experiences one of Canada's highest air pollution exposures because of the dual problem associated with continuing industrial emission and gradual increase of traffic related emissions along with the transboundary air pollutions from heavily industrialized neighboring north-eastern and mid-western US cities. These factors combined with meteorology, cause large degradation of Hamilton's air quality. Hence an appropriate and robust method is of most importance in order to get an early notification of the future air quality situation. Data driven methods such as neural networks (NNs) are becoming very popular due to their inherent capability to capture the complex non-linear relationships between pollutants, climatic and other non-climatic variables such as traffic variables, emission factors, etc. This study investigates dynamic neural networks, namely time lagged feed-forward neural network (TLFN), Bayesian neural network (BNN) and recurrent neural network (RNN) for short term forecasting. The results are being compared with the benchmark static multilayer perceptron (MLP) models. The analysis shows that TLFN model with its time delay memory and RNN with its adaptive memory has outperformed the static MLP models in ground level ozone (O_3) forecasting for up to 12 hours ahead. Furthermore the model developed using the annual database is able to map the variations in the seasonal concentrations. On the other hand, MLP model was quite competitive for nitrogen dioxide (NO_2) prediction when compared to the dynamic NN based models. The study further assesses the ability of the neural network models to generate pollutant concentrations at sites where sampling has not been done. Using these neural network models, data values were generated for total suspended particulate (TSP) and inhalable particulates (PM_10) concentrations. The obtained results show promising potential. Although there were under-predictions and over-predictions on some occasions, the neural network models, in general were able to generate the missing information and to obtain air quality situation in the study area.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Leveraging Distribution Quantiles to Detect Gene Interactions in the Pursuit of Personalized Medicine

contributor:
Meyre, David
Computational Engineering and Science

subject:
personalized medicine
Statistical Genetics
Obesity
BMI

abstract: Anticipations of personalized medicine are primarily attributed to the recent advances in computational science and high-throughput technologies that enable the ever-more realistic modeling of complex diseases. These diseases result from the interplay between genes and environment that have limited our ability to predict, prevent, or treat them. While many envision the utility of integrated high-dimensional patient-specific information, basic research towards developing accurate and reliable frameworks for personalized medicine is relatively slow in progress. This thesis provides a state-of-the-art review of current challenges towards personalized medicine. There is a need for global investment in basic research that includes 1) cost-effective generation of high-quality high-throughput data, 2) hybrid education and multidisciplinary teams, 3) data storage and processing, 4) data integration and interpretation, and 5) individual and global economic relevance; to be followed by global investments into public health to adopt routine personalized medicine. This review also highlights that unknown or unadjusted interactions result in true heterogeneity in the effect and relevance of patient data. This limits our ability to integrate and reliably utilize high-dimensional patient-specific data. This thesis further investigates the true heterogeneity in marginal effects of known BMI genetic variants. This involved the development of the novel statistical method, meta-quantile regression (MQR), to identify variants with potential gene-gene / gene-environment interactions. Applying MQR on public and local data (75,230 European adults) showed that FTO, PCSK1, TCF7L2, MC4R, FANCL, GIPR, MAP2K5, and NT5C2 have potential interactions on BMI. In addition, a gene score of 37 BMI variants shows that the genetic architecture of BMI is shaped by gene-gene and gene-environment interactions. The computational cost of fitting MQR models was greatly reduced using unconditional quantile regression. The utility of MQR was further compared to variance heterogeneity tests in identifying variants with potential interactions. MQR tests were found to have a higher power of detecting synergetic and antagonistic interactions for skewed quantitative traits while maintaining nominal Type I error rates compared to variance heterogeneity tests. Overall, MQR is a valuable tool to detect potential interactions without imposing assumptions on the nature of interactions.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The anticipations of personalized medicine are largely due to the recent advances in computational science and our capabilities to rapidly measure and generate biological data. These developments have enhanced our understanding of complex diseases, and should theoretically enable us to predict, prevent and treat such cases in a proactive personalized context. This thesis provides a state-of-the-art review of the challenges and opportunities that explain the relatively slow progress towards personalized medicine.  It identifies data integration and interpretation as the main bottleneck and proposes a novel method, termed Meta-Quantile Regression (MQR), to identify genetic variations with potential interactions. Analyzes were conducted on a total of 75,230 individuals with European ancestry, and the genetic architecture of obesity was shown to be shaped by genetic interactions. Lastly, the computational cost of MQR was substantially reduced using linear approximations, and MQR was further shown to have better performance in identifying potential interactions compared to classic variance tests.


title: Close-Up Stereo Triangulation with Application to Sheet Metal Strain Analysis

contributor:
Capson, David
Spence, Allan
Electrical and Computer Engineering

subject:
stereo
triangulation
sheet metal
strain analysis
application
close-up

abstract: This thesis describes an investigation into the experimental accuracy of a close-up stereo vision system. Surfaces are measured from any orientation through the synergy of a Coordinate Measurement Machine (CMM) and a custom made stereo vision head. Calibration of the stereo cameras is achieved using bundle adjustment non-linear optimization, commonly used in photogrammetry. Point set registration techniques are used to calibrate the stereo head with respect to the CMM coordinate system. The fully calibrated stereo vision system is used to provide experimental accuracy results under ideal imagining conditions. The system is then applied to the practical problem of sheet metal strain analysis. This problem involves many non-ideal imaging components that affect system accuracy. Experimental results for this non-deal situation are provided in the form of three-dimensional strain distribution plots.

abstract: Thesis

abstract: Master of Engineering (ME)


title: BRIDGING THE GAP: INCORPORATING EXERCISE EVIDENCE INTO CLINICAL PRACTICE IN BREAST CANCER CARE

contributor:
Richardson, Julie
Rehabilitation Science

subject:
breast cancer
oncology
exercise
physical activity
physiotherapy
knowledge translation

abstract:
This thesis includes four manuscripts with an overarching objective to develop, implement, and evaluate strategies to close the current knowledge to practice gap in the field of cancer rehabilitation. The overall goal of this objective is to provide a strategy to increase exercise knowledge and behaviour in women with breast cancer. The theory of planned behavior and knowledge-to-action cycle were used across these manuscripts in order to create and implement meaningful, easy-to-access, and effective interventions for women with breast cancer during chemotherapy treatment.
	The first manuscript presents a qualitative descriptive study outlining the barriers and facilitators to exercise promotion by health care professionals for women with breast cancer. Results found barriers to exercise promotion exist at the institutional, health care professional, and patient level. Patient complexity and availability of services and resources were found to influence exercise promotion in conjunction with the described barriers.
	The second manuscript presents a qualitative descriptive study using a focus group. The purpose of this study was to bring together a multi-disciplinary group of health care professionals who work with women with breast cancer to determine novel exercise intervention strategies to implement within the cancer care institution in Ontario. Results found that an on-site exercise program, an on-site rehabilitation professional, and more effective self-management educational strategies describing the benefits of exercise during and after breast cancer treatment were needed for women with breast cancer.
	The third manuscript presents a study protocol for the final thesis chapter. The purpose of this protocol was to describe a pilot study that would assess the feasibility and effectiveness of conducting an innovative knowledge translation intervention for breast cancer survivors using exercise and self-management versus usual care. The intervention was to be considered feasible if the recruitment rate reached >50%, adherence rate >75%, and retention rate >75%.
	The fourth manuscript presents the preliminary results of the pilot randomized controlled trial. The overall purpose of this study was to determine the feasibility of providing a complex knowledge translation intervention designed specifically for women with breast cancer using technology. This study also set out to explore preliminary estimates of effects of the knowledge translation intervention on physical activity level, exercise knowledge and behaviour, health related quality of life, overall health status, and resource utilization among breast cancer survivors. Results found the intervention to be feasible (recruitment rate of 96%, intervention retention rate of 100%, and intervention adherence rate of 89%). The exploratory findings of secondary outcomes found a significant between group difference in physical activity levels post intervention (mean difference= 25.38, 95%CI= (9.35, 41.42), p=0.003) as measure by the Godin Leisure-Time Exercise Questionnaire. No significant between group differences were found for exercise knowledge scores, health related quality of life, or overall health status.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Breast cancer survivors live with treatment-related side effects for years after their cancer treatments have ended. Regular participation in exercise can help to manage these side effects and improve quality of life in survivors. However, only small portions of breast cancer survivors take part in regular exercise. Many survivors are not aware of the benefits of exercise, how to exercise safely, or where exercise related services are available. There is a large gap between the research evidence supporting the use of exercise for women with breast cancer, and actual clinical practice. This thesis includes four papers aimed at devising and implementing a knowledge translation strategy in order to close this knowledge to practice gap in Ontario. Results suggest that an innovate program including exercise and self-management education run by a physiotherapist within the cancer institution is feasible and safe for women with breast cancer during chemotherapy.


title: O-Glycosylation of B-Catenin Regulates its Nuclear Localization and Transcriptional Activity

contributor:
Persad, S.
Biochemistry and Biomedical Sciences

subject: glycosylation beta-catenin nuclear transcription

abstract: B-catenin is a transcriptional co-activator in the Wnt signaling pathway. Upon Wnt stimulation, cytosolic B-catenin translocates into the nucleus where it forms complexes with members of the TCF /LEF family of transcription factors to activate gene transcription. Translocation into the nucleus is followed by transcriptional activation of B-catenin's target genes, which are involved in proliferation, angiogenesis and oncogenesis, is a crucial step in the progression of a subset of cancers. The cellular expression of B-catenin is known to be regulated by phosphorylation. However, the mechanisms(s) responsible for B-catenin nuclear entry is not well understood. Recently, B-catenin was reported to be post-translationally modified by O-glycosylation in breast cancer cells. We investigated whether O-glycosylation regulates the signal transduction properties of the protein. Our results indicated that while there are higher levels of total B-catenin in the nucleus of two prostate cancer cell lines (DU-145 and LNCaP) compared to that in a normal prostate epithelial cell line (PNT1A), most of it was in the unglycosylated form. Also, the normal prostate cell line exhibited higher levels of O-glycosylated B-catenin in both the nucleus and cytosol than what was seen in the two prostate cancer cell lines. We carried out further experiments using PUGNAc, a non-cytotoxic reversible inhibitor of O-GlcNAcase, which causes a time dependent increase in cellular levels of O-glycosylated B-catenin. Treatment of prostate cancer cells with PUGNAc caused a decrease in the expression of B-catenin in the nucleus with increasing cellular O-glycosylation of the protein suggesting that O-glycosylation was hindering B-catenin nuclear translocation. Additional studies showed that O-glycosylation of B-catenin decreased that transcriptional activity of a TopFlash reporter plasmid and the protein expression of two B-catenin target genes. Our results suggest that O-glycosylation of B-catenin may represent a novel mechanism important in the regulation of the nuclear localization and transcriptional activity of B-catenin.

abstract: Thesis

abstract: Master of Science (MS)


title: Implantable Alginate Microcapsules as Gene Therapy for Hemophilia A

contributor:
Hortelano, Gonzalo
Biomedical Engineering

subject:
alginate
microcapsules
gene therapy
hemophilia

abstract: Hemophilia A is an X-linked recessive bleeding disorder caused by the deficiency of coagulation factor VIII [1]. Current treatment for hemophilia A consists of prophylactic or on demand replacement therapy of either plasma-derived or recombinant FVIII concentrates [2]. Albeit effective, there are several limitations associated with factor concentrates, including high cost that limits its availability for close to 80% of hemophilia patients in developing countries [3-5]. An alternative treatment would thus be desirable. Gene therapy for hemophilia has seen many successes in animal models and represents a more cost-effective alternative to the current treatment modalities [6]. In the current work, I present a gene therapy system for hemophilia that uses mouse fetal myoblasts engineered to secrete FVIII, enclosed in immuno-protective alginate-poly-L-lysine-alginate (APA) microcapsules, as a sustained source of FVIII. In this study, a thorough examination of the encapsulated myoblasts using a novel flow cytometry assay was performed. This method yielded an accurate and precise method for encapsulated cell viability calculation, and also allowed for analysis of several other parameters such as health (cell morphology), cell size and distribution. Flow cytometry was also used to monitor the time-course proliferation profile of encapsulated myoblasts secreting cFVIII, using the division tracking dye CFSE. We found that encapsulated cells display a decreased proliferation rate as well as lower viability than non-encapsulated cells. Implantation of encapsulated G8 myoblasts secreting cFVIII into hemophilia A mice resulted in maximum plasma levels of protein on day 1 ( ~18% of normal canine FVIII levels). Delivery of cFVIII in hemophilic mice also offered protection against blood loss after the mice were subjected to injury (as measured by hematocrit levels); indicating that biologically functional cFVIII continued for at least 7 days post-capsule implantation. Low levels of FVIII antigen returned on day 28 after a transient disappearance on day 14. However, the presence of antigen must be reconciled with appearance of anti-cFVIII antibodies that were detected in the plasma of treated mice at the end of five weeks. The neutralizing nature of these antibodies still needs to be characterized by Bethesda assay Overall, our study demonstrates the feasibility of delivering therapeutic levels of FVIII using encapsulated G8 fetal myoblasts. The presence of functional FVIII protein on day 7, suggests that this treatment was not met by transcriptional repression in vivo, thereby overcoming one of the major obstacles faced by using the transformed C2C12 cell line secreting hFVIII [7] If such levels of FVIII were achieved in humans, it would be sufficient to convert a severe hemophiliac into a mild phenotype. Thus, this gene therapy strategy may be a suitable therapeutic alternative for hemophilia patients. Further work ought to focus on the long-term persistence of FVIII in hemophilia A mice, and also determining the protection following trauma over time to determine if the FVIII remains functional. Other cell lines should be explored for higher expression, reduced immunogenicity and improved viability Still, there is a need to develop human cells expressing high levels of biologically active hFVIII with similar properties to the fetal cells described in this study [8, 9]

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Intimate Partner Violence: An Exploration of Research Transparency, Quality, and Opportunities

contributor:
Bhandari, Mohit
Health Research Methodology

subject:
intimate partner violence
research methodology
orthopaedics
transparency

abstract: Intimate partner violence is also known as domestic violence or spouse abuse.  It affects the physical, psychological, social, and financial well-being of many people around the world.  Many researchers from health/medical, social, and psychological fields have studied intimate partner violence in an effort to prevent it or to improve overall health and well-being among victims.  Ideally, decisions are best influenced by high quality evidence.  However, little attention has focused on the quality of this research.  This thesis focuses on the theme of transparency relating to study quality, specifically highlighting non-publication bias, biases related to outcome and study methodologies, and overall reporting quality in previously published IPV research.  These lessons learned from this research have informed, in part, an original study on intimate partner violence.  Finally, this thesis concludes with insights to improve methodological quality and transparency for researchers in the intimate partner violence field.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: USING DYNAMIC MIXINS FOR SOFTWARE DEVELOPMENT

contributor:
Sekerinski, Emil
Computing and Software

subject:
programming languages, mixins
object models

abstract: Object-oriented programming has gained significant traction in the software development community and is now the common approach for developing large, commercial applications. Many of these applications require the behaviour of objects to be modified at run-time. Contemporary class-based, statically-typed languages such as C++ and Java require collaboration with external objects to modify an object’s behaviour.  Furthermore, such an object must be designed to order to support such collaborations.  Dynamic languages such as Python which natively support object extension do not guarantee type safety.  In this work, using dynamic mixins with static typing is proposed as a means of providing type-safe, object extension. A new language called mix is introduced that allows a compiler to syntactically check the type-safety of an object extension. A model to support object-oriented development is extended to support dynamic mixins.  The utility of the approach is illustrated using sample use cases. Finally, a compiler was implemented to validate the practicality of the model proposed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Comparison of Two Hydrologic Modeling Approaches for the Estimation of Flood Frequency Distributions

contributor:
Guo, Y.
Civil Engineering

subject:
hydrologic
flood
frequency distribution

abstract: Several previous studies have compared design storms with continuous simulation results for the purposes of estimating flood frequency distributions. These previous studies were limited in scope to primarily urban single lumped catchments. This thesis attempted to perform a more detailed comparison of design storm and continuous simulation flood frequency distributions by extending the analysis to different basin types, as well as examining the effect of more complex watershed systems and storage elements (detention ponds). It was found that design storms could reasonably reproduce continuous simulation flood frequency distributions if an appropriate distribution and antecedent conditions were selected. Design storms were found to compare increasingly well to continuous simulation results in more complex watershed systems and through storage elements.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Experimental Study of the Behaviour and Strength of Deep Concrete Beams Reinforced with CFRP Bars

contributor:
Razaqpur, A.
Civil Engineering

subject:
behaviour
strength
concrete
deep concrete beam
reinforce
CFRP bar

abstract: An experimental program was conducted to investigate the strength and deformations of deep beams reinforced with Carbon Fibre Reinforced Polymer (CFRP) longitudinal and transverse reinforcement. Two groups of beams were tested, with each group comprising three beams. Two of the three beams in each group were reinforced with CFRP bars while the third beam was reinforced with conventional rebars and the latter beam was used as a control specimen. Beams in group 1 had span-to-depth ratio of one, while those in group 2 had a span-to-depth ratio of two. Beams in both groups had height of 900 mm and width of 250 mm. All the beams were simply supported and were tested in four-point bending with the point loads applied at one-third of the span. The test results revealed no significant difference between the behavior of the FRP reinforced beams and the companion control beams. On the other hand due to lack of hooks at the ends of the CFRP bars, and the loss of bond between the CFRP fibres and the sand grains on the surface of the bar, the failure in the CFRP reinforced beams was caused by the loss of anchorage while in the steel reinforced beams, the failure was initiated by the yielding of the longitudinal steel, followed by the crushing of the horizontal compression strut, but the nodal zones did not fail in any of the beams. Consequently, it was concluded that CFRP reinforced deep beams could be designed using the current CSA method for conventional steel reinforced concrete deep beams, provided the anchorage or bond strength of FRP bars could be properly determined. The existing nodal efficiency factors for the CCC nodal zones, as given in the CSA A23.3. standard, could be applied to CFRP reinforced beams while the corresponding factor for the CCT zone may be conservatively assumed to be 0.68. Finally, despite the linear elastic behavior of CFRP reinforcement, deep beams reinforced with CFRP bars could be designed using strut and tie models.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The PULSES Project: Teaching the Vital Elements of Code Status Discussions to Postgraduate Oncology Trainees

contributor:
Brouwers, Melissa
Health Research Methodology

subject:
oncology
code status
communication training
postgraduate medical education

abstract: Canadian national survey of oncology residency program directors and trainees; randomized trial of medical education intervention

abstract:
Purpose:  This work addresses teaching communication skills for eliciting cardiopulmonary resuscitation (CPR) wishes, or code status discussions, with cancer patients.  The objectives of this thesis include: 1) define current teaching practices for code status communication training in Canadian oncology residency programs, and 2) examine the effect of teaching a novel communication framework for code status discussions to oncology residents.
Methods:  All current residents and program directors in Canadian medical and radiation oncology residency programs were surveyed regarding education, perceived gaps in training, attitudes towards and patterns of clinical practice for code status discussions with cancer patients.  We carried out a multicentre randomized trial to determine the effect of teaching a code status communication framework to oncology learners.  Residents completed a training workshop and were evaluated in simulated patient encounters (observed structured clinical exam [OSCE]).  Participants were randomized to complete the training before the OSCE (experimental arm), or after the OSCE (control arm). The primary outcome was objective rating of code status communication skills.
Results:  Current postgraduate oncology curricula lack formal teaching and evaluation of code status communication skills.  Educators support the need for innovative teaching tools in this field.  Accordingly, a novel six-step communication framework was created in which core themes were summarized by the mnemonic acronym PULSES (Prognosis, Underlying values, Long-term outcome and Short-term outcome of CPR, provision of an Educated recommendation, Summary, style and documentation).  A total of 46 oncology residents from 3 training centres participated in the randomized trial.  Overall, learners in the experimental group had higher mean content-specific, general communication, and global rating communication scores than those in the control group. The training program conferred the greatest benefit among junior residents.  Scores across rating tools were highly correlated.
Conclusions:  Communication training for code status discussions in Canadian oncology residency programs is lacking.  With use of a novel communication framework, we have shown that structured teaching on code status discussions can improve competence in this challenging communication task.  Moreover, we have developed educational resources that can be implemented in current curricula.  Building capacity for clear and effective code status communication with cancer patients will contribute to high quality end of life care in Canada.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Medical learners in oncology (cancer care) training programs often lead discussions with cancer patients about code status, that is, patients’ wishes for use or non-use of life-sustaining resuscitation interventions including CPR.  Learners receive little training for these complex encounters; yet, decisions regarding resuscitation wishes can influence the quality of care received by cancer patients at end of life.  In this study we conducted a survey of trainees and program directors in Canada to better understand current educational practices and attitudes towards education on this topic.  Most trainees are not receiving formal teaching or evaluation, and new educational resources are needed.  We then developed a 6-step communication guide for code status discussions.  We studied the effect of a training workshop in which the communication guide was taught to learners in oncology.  We found that the training program improved communication ability among learners with the greatest impact seen among junior learners.


title: Sprint Interval Training During Inpatient Rehabilitation After Spinal Cord Injury

title: Sprint SCI

contributor:
Hicks, Audrey
Kinesiology

subject:
Spinal Cord Injury
Exercise
Inpatient Rehabilitation
Sprint Interval Training
Arm-Ergometry
Exercise Rehabilitation

abstract:
During inpatient rehabilitation, arm-ergometry training is utilized to improve the physical
capacity of patients with a sub-acute spinal cord injury (SCI) to a level that is desirable for
performing activities of daily living (ADLs). Previous work has demonstrated that ≥ 20
minutes of moderate-intensity continuous training (MICT) during inpatient rehabilitation, at a
frequency of ≥ 3 times per week, is useful for increasing the physical capacity of these
patients. However, considering that inpatient rehabilitation is an intensive program, and given
the trend towards a shortened length of stay during inpatient rehabilitation, performing MICT
on the arm-ergometer can consume a valuable amount of therapy time. Low-volume sprint
interval training (SIT) is a time-efficient alternative to MICT for improving indices of
physical fitness in healthy and diseased populations. To date, however, there are no published
studies comparing SIT to MICT in persons with sub-acute SCI undergoing inpatient
rehabilitation.The purpose of this thesis was to evaluate the efficacy of a five-week, thrice
weekly low-volume SIT protocol on the arm-ergometer and compare fitness outcomes to
traditional MICT in patients with sub-acute SCI undergoing inpatient rehabilitation.
Participants with sub-acute SCI undergoing inpatient rehabilitation were recruited and
randomly allocated to the SIT or MICT training group. Both types of training utilized the
same 2 min. warm-up and 3 min. cool-down. SIT consisted of 3 x 20 sec. “all-out” cycle
sprints (≥ 100% of peak power output [POpeak]), interspersed with 2 min. of low activerecovery
(≈ 10% of POpeak; total time commitment, 10 mins). MICT involved 20 min. of arm
cycling (45 – 60% of POpeak; total time commitment, 25 mins). SIT elicited a higher relativheart rate response, and ratings of perceived exertion than MICT. Following training, we
found similar improvements in maximal and sub-maximal physical capacity across groups.
Both exercise modes were equally well tolerated, and enjoyable, and there were no differences
in self-efficacy across groups. The significance of this work is that it is the first randomized-controlled trial
comparing SIT to MICT on the arm-ergometer in individuals with sub-acute SCI undergoing
inpatient rehabilitation. The fact that SIT is palatable and can promote similar increases in
physical capacity as MICT, despite less than half the time commitment and training volume,
means that clinical rehabilitation specialists can now offer a new, more time-efficient, exercise
training strategy to elicit improvements in their patients.

abstract: Thesis

abstract: Master of Science (MSc)


title: Electrophoretic deposition of inorganic-organic nanocomposites

contributor:
Zhitomirsky, Igor
Materials Science and Engineering

subject: EPD, inorganic-organic nanocomposites, liquid-liquid extraction

abstract:
With many processing advantages, electrophoretic deposition (EPD) has
been chosen as the fabrication technique for inorganic-organic
nanocomposites. However, before the EPD process, avoiding the particles
agglomeration is considered a necessary perquisite for the success of
fabrication.
In this research, two different liquid-liquid extraction methods, one is
one-step and the other is two-step, were developed to solve the
agglomeration problem of inorganic particles. The adsorption
mechanisms of the extractors and extraction mechanisms were
investigated during this work. The strong adsorptions provided by –OH
groups of the extractors and further Schiff base reaction allowed for the
process of extraction.
In the fabrication, polyelectrolytes acted as the film forming and charging
agents. Relatively stable suspensions with extracted inorganic particles
were prepared for the EPD of inorganic-organic nanocomposites. The
thickness of deposited films is proportional to the concentration of the
suspension and deposition time. With the addition of flame retardant
inorganic particles, the prepared nanocomposite films showed an
enhanced flame retardant performance.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Metabolomic Assessment of Dietary Interventions in Obesity by Capillary Electrophoresis Mass Spectrometry

contributor:
Britz-McKibbin, Philip
Chemistry and Chemical Biology

subject: Capillary electrophoresis, Mass spectrometry, Metabolomics, Untargeted metabolite profiling, Dietary interventions, Obesity, Thiols, Maleimide, Chemical derivatization, Biomarkers, Biological fluids, Caloric challenge, Caloric restriction, Nutrition, Soy, Whey, Protein supplementation, Method validation, Data filtering, Statistical analysis, Urine, Serum, Plasma

abstract:
Capillary electrophoresis mass spectrometry (CE-MS) is a versatile instrumental
method for metabolomics, which allows for comprehensive metabolite profiling of
volume-limited biological specimens in order to better understand the molecular
mechanisms associated with chronic diseases, including an alarming epidemic of
obesity worldwide. Multiplexed CE separations enable high-throughput metabolite
screening with quality assurance to prevent false discoveries when combined with
rigorous method validation, robust experimental designs, complementary statistical
methods, and high-resolution tandem mass spectrometry (MS/MS) for unknown
metabolite identification. In this thesis, multiplexed CE-MS technology is applied for
both targeted and untargeted metabolite profiling of various biological fluids, including
covalently bound thiol-protein conjugates, as well as free circulating metabolites in
serum and plasma, and excreted/bio-transformed compounds in urine due to complex
host-gut microflora co-metabolism. This work was applied to characterize aberrant
metabolic responses of obese subjects in response to dietary challenges, and measure
the benefits of dietary interventions that reduce adiposity without deleterious muscle
loss. Chapter 2 presents, a simple, sensitive yet robust analytical protocol to expand
metabolome coverage in CE-MS for the discovery of labile protein thiols in human
plasma using a rapid chemical derivatization method based on N-tert-butylmaleimide
(NTBM). Chapter 3 describes targeted metabolite profiling of serum and plasma
to investigate the differential metabolic responses between healthy and unhealthy
obese individuals before and after consumption of a standardized high-caloric meal,
respectively. Chapter 4 of this thesis describes an untargeted metabolite profiling
strategy for urine using multisegment-injection (MSI)-CE-MS for elucidating the effects of protein supplementation following a short-term dietary weight-loss intervention
study. This work revealed six urinary metabolites that were classified as top-ranking
treatment response biomarkers useful for discriminating between subjects consuming
carbohydrate (control), soy, and whey supplemented diets. In summary, this thesis
demonstrated the successful implementation of multiplexed CE-MS technology for
biomarker discovery in nutritional-based metabolomic studies as required for more
effective treatment and prevention of obesity for innovations in public health.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Modeling and Control of Miniature Servo Pneumatic Actuators

contributor:
Bone, Gary M.
Mechanical Engineering

subject:
model
control
servo
pneumatic actuator

abstract: Pneumatic actuators are low-cost, safe, clean, and exhibit a high power to weight ratio. In this thesis a novel servo pneumatic system based on miniature cylinders is presented. The first cylinder investigated has a 9.5 mm bore size. Four low-cost 2-way proportional valves are incorporated to provide greater design flexibility than the traditional single 4-way servo valve solution. A nonlinear system model is developed and validated using open-loop experiments. The use of bipolynomial functions to model the valve flow rates is shown to provide a more accurate solution than the commonly used nozzle flow equations. Two multiple-input single-output nonlinear position controllers are designed using the inverse dynamics and backstepping method respectively. In addition to position control, the control designs allow a second control objective to be implemented. In the inverse dynamics controller, the chamber pressures are controlled in inner loops and the position is controlled in an outer loop. In the backstepping controller, the stability analysis includes the effects of friction modeling error and valve modeling error. In experiments with a 1.5 kg moving mass, the inverse dynamics controller produced SSE within ±0.08mm and the backstepping controller ±0.05mm. The two control laws produced maximum tracking errors of ±0.5 mm and ±0.3mm for a 1 Hz sine wave trajectory respectively. The tracking errors are shown to be 85% less than those produced by a linear controller. Experiments demonstrate that the two controllers are robust to the system operating in horizontal and vertical orientations. They are also robust to an increase of payload but not to a decrease of payload. This problem can be overcome by tuning the controller parameters for the smallest payload. The two controllers are further tested with miniature cylinders with different bore diameters and stroke lengths. The smallest cylinder tested has a 4 mm bore diameter.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Numerical and Experimental Study of the Deformation of Gray Cast Iron Plates

contributor:
Hamed, Mohamed
Ali, A. A.
Mechanical Engineering

subject:
numerical study
experimental study
deformation
gray cast iron
cast iron
plates

abstract: Helical heating coils are widely used in most conventional electric stoves for many years, these heating coils can reach 600-700°C, which is higher than the ignition point of oil and grease (about 400°C), leading to many fires. Pioneering Technology Inc. has developed a Safe-T Element plate to address such problem. The Safe-T Element plate is manufactured from Gray Cast Iron. However, these plates deform during its use. This study was carried out to investigate the current Safe-T Element design, both experimentally and numerically, in order to determine the root causes behind the deformation problem of the plate, and to suggest changes to the existing design in order to limit its distortion to acceptable targets. A chemical analysis was carried out to establish the type of material of the Safe-T Element plate. Chemical analysis showed that the material of the plate is cast iron. The microstructure of the plate was tested in order to examine its type and homogeneity. Tensile testing was carried to establish the grade of the material, and to calculate the value of its young's modulus and yield strength. Tensile testing indicated that the material of the Safe-T Element plate is close to Gray Cast Iron Class 40. Differential scanning calorimetry testing was carried out to investigate thermal stability of the plate material. This test indicated that material is thermally stable. Thermal cycling testing indicated that the root cause of the deformation problem is elastic thermal buckling. Temperature uniformity tests were carried out. More than 100°C temperature variation in the radial direction was observed. To address the distortion of the plate, an optimum geometry has been suggested based on the findings of the numerical investigation by removing the outer ring from the original design of the plate.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Group 2 Innate Lymphoid Cells are Increased in Patients with Moderate-To-Severe Atopic Dermatitis

contributor:
Sehmi, Roma
Medical Sciences

subject:
Innate Lymphoid Cells
ILC2
Atopic Dermatitis
Group 2 Innate Lymphoid Cells

abstract:
Introduction: Atopic dermatitis (AD) is characterized by chronic pruritic relapsing eczematous lesions of the skin. Eosinophilic inflammation in AD is driven by activation of type 2 inflammatory cells including CD4+ T cells and type 2 innate lymphoid cells (ILC2s). We have shown that type 2 cytokines, namely interleukin (IL)-5 and IL-13, stimulate migration and terminal differentiation of eosinophil progenitor cells (EoPs). We propose that these cytokines are important drivers of tissue eosinophilia in AD lesional skin. This study aimed to quantify, by flow cytometry, cells that produce type 2 cytokines in lesional skin compared to peripheral blood from moderate-severe AD patients.
Methods: In a cross-sectional study of patients with moderate-to-severe AD (n=16), type 2 inflammatory cells were enumerated in blood and cells extracted from excised skin biopsies. By flow cytometry, live, singlet CD45+cells were identified as ILC2 (lin-CD127+CD294+), EoP (CD34+125+), and CD4+ T cells (Lin+CD3+CD4+). Intracellular expression of type 2 cytokines (IL-5 and IL-13) were evaluated in each cell population. In addition, we developed a protocol to enumerate ILC2s by fluorescence immune-histochemistry in lesional versus non-lesional skin samples and skin biopsies taken 24h post-intradermal challenge with allergen versus diluent.  Data are expressed as median (interquartile range [IQR]) unless otherwise stated. Cross compartmental comparisons were made using the Wilcoxon rank-sum test and where applicable, correlational analyses were performed using a Spearman’s rank-correlational test.
Results: There was a significantly higher number of total ILC2s in lesional skin compared to blood from AD subjects (556 [99 – 5501] vs 235 [67 – 569] cells/mL, p=0.03). Similarly, IL-5+, IL-13+ ILC2s, were significantly greater in skin compared to blood (6 [1 – 666] vs 1 [1 – 19] cells/mL, p=0.03; 28 [1 – 1357] vs 1 [1 – 7] cells/mL, p=0.01, respectively). We found higher numbers of total and type 2 cytokine positive EoP in lesional skin biopsies from AD patients compared to blood (Total EoP: 815 [285 – 2794] vs 112 [46 – 247] cells/mL, p<0.01; IL-5+EoP: 36 [1 – 129] vs 1 [1 – 23] cells/mL, p=0.07; IL-13+EoP: 92 [10 – 182] vs 1 [1 – 8] cells/mL, p<0.01 and IL-5+IL-13+ILC2: 70 [1 – 158] vs 1 [1 – 12] cells/mL, p=0.02, respectively). In contrast, significantly higher numbers of total and type 2 cytokine positive CD4+ cells were found in blood compared to lesional skin biopsies from AD patients (Total CD4+: 1092 [650 – 1742] vs 58.3 [35.3– 152.4] x 103 cells/mL, p<0.01 and  IL-5+IL-13+CD4+ cells: 13.5 x 103 [2.1 x 103 – 42.9 x 103] vs 3.8 x 103 [1.6 x 103 – 4.9 x 103] cells/mL, p=0.02, respectively). For IF staining, there was a significant higher number of ILC2s in lesional compared to non-lesional skin biopsies and biopsies taken 24h post allergen- compared to diluent challenge (1 [0 – 2] vs 0 [0 - 0] cells/mm2, p=0.008, and 2 [1 – 2] vs 0 [0 – 0] cells/mm2, p=0.0002, respectively). Interestingly, in sex analyses we found significantly greater levels of blood ILC2 in females compared to males, but this not was found in the skin. Importantly, we found a significant correlation between lesional skin levels of ILC2 measured by flow cytometry and clinical measures of disease severity/symptoms as reported/calculated from the Patient-Oriented Eczema Measure questionnaire (POEM) score (total ILC2: r=0.55, p=0.04; IL-13+ ILC2s, r=0.61, p=0.02 and IL-5+ IL-13+ ILC2s: r=0.75, p=0.002).
Conclusions: Preferential increases in skin-resident ILC2 that produce a type 2 rich environment were found in AD subjects. These levels correlated with patient-oriented measure of disease severity. We propose that this increase may encourage recruitment of mature eosinophils and EoP and possibly drive localized differentiation of EoP into mature eosinophils that may drive the pathology of AD lesions. Furthermore, immunofluorescence staining may be a suitable alternative to flow cytometry for identification of ILC2 in the event of a low cell count. These techniques can be used in future studies that target ILC2 biology to fully understand the role of these cells in driving AD.

abstract: Thesis

abstract: Master of Science (MSc)


title: Correlations Between Geometric and Material Properties of Vertebral Bodies and Their Compressive Strength

contributor:
Kasra, Mehran
Mechanical Engineering

subject:
geometric
material properties
vertebral bodies
compressive strength

abstract: Osteoporosis is a disease characterized by reduced bone strength leading to an increased fracture risk. Current diagnostic best practice involves measuring the bone mineral density (BMD) of a patient using absorptiometric imaging tools. This measurement is compared to a known value in order to compute fracture risk. This assessment of bone quality is based solely on the BMD, which has been shown to make up only a portion of the explanation of bone strength. The extent of BMD's contribution to bone strength is also extensively debated and widely varying in the scientific literature. This thesis work encompasses a preliminary investigation into factors in addition to density that contribute to bone strength. The geometric and material properties of 21 vertebral functional unit specimens were measured using dual energy absorptiometry (DXA), pQCT (peripheral quantitative computed tomography) and HCT (helical computed tomography) techniques. The strength of the functional units was assessed through mechanical testing under compressive loading conditions. These measurements were amalgamated into multiple linear regression models to characterize vertebral strength in terms of a few key variables. The model developed for failure load had a coefficient of determination of 0.725 and indicated that the volume of the vertebral body as well as the cross-sectional area of the cortical region were significant in the explanation of failure load. A model was also developed for stress at failure which indicated that the vertebral body height and cortex concavity were important parameters. The coefficient of determination for this model was 0.871. The goal of this study was to provide a foundation on which further investigation into the explanation of bone strength could be built. Ultimately, a better understanding of the parameters that affect bone strength will provide a basis for more accurate clinical tools for the diagnosis of osteoporosis.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Effects of Strain Path Changes on Damage Evolution and Sheet Metal Formability

contributor:
Wu, Peidong
Mechanical Engineering

subject:
strain path
damage
evolution
sheet metal
formability

abstract: The concept of the Forming Limit Diagram (FLD) has proved to be useful for representing conditions for the onset of sheet necking, and is now a standard tool for characterizing materials in terms of their overall forming behavior. In this study, the M-K approach, in conjunction with Gurson model, is used to calculate FLDs. The influences of mechanical properties, including strain hardening, strain rate sensitivity, as well as the void nucleation, growth and coalescence, on the FLDs are examined. Most sheet metals undergo multiple deformation modes (strain paths) when being formed into complex manufacturing parts. When the strain path is changed in the deformation processing of metal, it's work-hardening and flow strength differs from the monotonic deformation characteristics. As a consequence, sheet metal formability is very sensitive to strain path changes. In this study, the hardening behavior and damage evolution under non-proportional loading paths are investigated. The effect of strain path change on FLDs is studied in detail. FLDs are conventionally constructed in strain space and are very sensitive to strain path changes. Alternatively, many researchers represented formability based on the state of stress rather than the state of strain. They constructed a Forming Limit Stress Diagram (FLSD) by plotting the calculated principal stresses at necking. It was concluded that FLSDs were almost path-independent. In this work, the FLSD has been constructed under non-proportional loading conditions to assess its path dependency when damage effect is included.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Sensor-Based Collision Avoidance for Industrial Robotic Arms

subject:
robot
robotic arm
industrial robot
collision avoidance
sensor-based collision avoidance

abstract: Robotic automation has evolved to be an irreplaceable part of production lines. Orderly operation of the robots is a key factor. Yet robots often have to deal with unpredictable factors including human beings or possible failures that lead to unexpected behaviours. Collision avoidance mechanisms are therefore of outmost importance to prevent injuries and damage. A major challenge in the creation of a dependable collision avoidance system is the sensory system that could cover relevant parts of the robot and capacitive sensors are a promising solution. The burden is to overcome the nonlinearity and other limitations of the capacitive sensors and harness their potential to this end. It is cumbersome to estimate the proximity of surfaces of the robot from its environment (which could include other robots) from the capacitive readings, so a novel sensing approach is proposed in this thesis. For industrial applications where the motions are well-defined, a pre-recorded capacitive signature can be used to monitor for unexpected changes. In this thesis the capacitive signature of one or more robotic arms will be used to predict and prevent collisions in a robotic workcell. A short training cycle is used to create a signature that is used at runtime to monitor the robot operation. Capacitive electrodes are placed on strategic locations on the robot arms and the surrounding environments and a supervisor computer uses the readings to cease the operation in case of any abnormality. This thesis describes the details of generating the signature from the training data and the runtime software. The supervisor computer provides a pause and/or go signal to the robot(s). The native controller of each arm is kept in place and the only change needed is the ability of each controller to pause the arm at command when a collision is detected and continue from this paused state. This approach requires minimum changes to the existing robotic equipments and programmes. These hardware requirements are widely available on existing controllers. Signature creation is the process of finding the normal pattern of the capacitance readings from all sensors as well as some expected limits allowing for the variations that are to be expected. The algorithms, reasoning, and experimental data are provided throughout the text. The system is tested on a robotic workcell that includes an actively controlled robot and a passive revolute joint. While the algorithm is universal, the suggested hardware has been shown to provide sampling times of down to 20ms, and positional accuracies of ±2mm or better are achieved for the test setup. The thesis also proposes methods to expand the measurement hardware for increased protection and fault tolerance.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Genetic Analysis of Pry-1/Axin Function in the Nematode Caenorhabditis Briggsae

title: Genetic Analysis of PRY-1/Axin in Caenorhabditis Briggsae

contributor:
Gupta, Bhagwati
Biology

subject:
genetic
genetic analysis
pry-1/axin
nematode
caenorhabditis
caenorhabditis briggsae

abstract: Evolutionary variations during vulval development in C. elegans and its related nematode species are well analyzed. The formation of C. elegans vulva involves many complex cell-cell interactions that are mediated through well conserved EGF/EGFR/RAS, LIN12/Notch and WNT signaling pathways. These pathways specify distinct cell fates of the six epidermal vulval precursor cells (VPCs), P(3-8).p. pry-1/Axin in C. elegans is identified as a part of destruction box complex that mediates (beta)-catenin degradation and is known to negatively regulate canonical Wnt signaling pathway during its development. I focused on the genetic analysis of pry-1 I Axin function in C. briggsae, sister species to C. elegans, to study inter-species comparisons of vulva formation. Three alleles, lin(sy5353), lin(sy5411) and lin(sy5270) were genetically mapped to LG I using standard genetic and in del mapping techniques. Interestingly, a unique simultaneous Multi vulva and Vulvaless (Muv-Vul) phenotype was observed during vulva formation in Cbr-pry-1 alleles, resulting from the varying induction potentials of the VPCs along the A/P axis, compared to Cel-pry-1 animals. In order to analyze these phenotypic differences between Cel-pry-1 and Cbr-pry-1 in greater detail, I dissected vulval development in sy5353 animals. VPC competence analysis was done through cell lineages and ablations studies, while the C. briggsae vulval cell fate markers were used for cell fate specification analysis. Cell ablations revealed that P7.p and P8.p in Cbr-pry-1 animals exhibited non-competence towards anchor cell signaling. Additionally, gonad-independent inductions was observed in P(3-8).p cells and they adopted 2° cell fate specifications. Using RNAi approach, Cbr-pry-1 interactions with other vulval pathway genes were dissected and it was observed that Cbr-lin-12 is involved in VPC competence of P7.p and Cbr-pop-1 exhibited different regulatory levels during vulval development compared to C. elegans. Thus, it can be inferred that the mechanisms of vulva formation in C. briggsae has evolved through changes in the competence of VPCs.

abstract: Thesis

abstract: Master of Science (MS)


title: Putting the Patient First: Self-Care App For Heart Failure

title: Qualitative data collection for development of an electronic application to promote home- based self-care in older heart failure patients: patient and informal caregiver perspectives

contributor:
Demers, Catherine
Samavi, Reza
Mbuagbaw, Lawrence
Keshavejee, Karim
eHealth

subject:
mhealth
eHealth
Heart Failure
Self-Care

abstract:
Heart failure (HF) affects many older Canadians with recurrent hospitalizations despite post-discharge strategies to prevent readmission. Self-care is key to the management of HF in the home setting and can potentially lead to better clinical outcomes. Proper HF self-care includes tasks such as daily weight and symptom monitoring, as well as adjusting diuretics based on weight.  Patients find HF self-care challenging, with less than 50% of patients regularly weighing themselves.
Mobile applications to support self-care have been shown to be effective, however, due to their lack of consideration for barriers such as literacy, numeracy and cognitive impairment within their design, these applications are not usable for many older patients. Previous work supports the use of a paper-based standardized diuretic decision support tool (SDDST) to promote self-care in older individuals with HF. The objective of this study was to use participant (HF patients, informal care-providers) input to convert the paper-based SDDST into a user-centered electronic mobile application.
We recruited 12 patients (male and female, age > 60 years) with a confirmed diagnosis of HF, and 7 informal caregivers from the Heart Function Clinic at the Hamilton Health Sciences General site. HF patients were categorized into three groups, 1) adequate self-care patients (6), 2) inadequate self-care patients without a CP (2) or 3) inadequate self-care patients with a CP (4), based on their self-care abilities measured with the Self-Care Heart Failure Index (SCHFI) where a score of > 70 is considered self-care adequate. We conducted semi-structured interviews with HF patients and CPs using Persona-Scenarios. Interviews were analyzed using NVivo, version 10, for emerging themes regarding self-care.
Following data analysis, we identified 6 major themes, 1) Usability of technology, 2) Communication, 3) Application customization, 4) Complexity of Self-Care, 5) Usefulness of HF Related Information and 6) Long-Term Use and Cost. Many of the challenges patients and CPs mentioned involved their unfamiliarity with technology. However, by addressing these themes, we were able to develop a series of requirements and modifications to improve the usability of our app design.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
Heart failure (HF) is one of the leading causes of hospitalization and re-hospitalization in older adults. . If patients are able to take care of themselves (self-care) at home they will be less likely to be readmitted to the hospital. However, many patients find self-care difficult, so they do not manage their symptoms.
To assist patients in understanding or following their treatment, various mobile health applications have been developed. Unfortunately, older patients do not commonly use these applications because of their complicated design.
In this study, we interviewed patients and their informal caregivers to help design our HF self-care app. We gathered information on features they may perceive to be helpful. Our goal was to use their feedback to make the app simpler and more user-oriented, which will make self-care easier.


title: Activation of TLR4 by Tenascin C through the induction of Interleukin-6 in the Fragile X Mouse Model

title: IL-6 Secretion by Astrocytes in Fragile X Mice

contributor:
Doering, Laurie
Medical Sciences

subject:
astrocytes
development
Fragile X Syndrome
Tenascin C
TLR4
synapses
mouse model

abstract: Fragile X syndrome (FXS) is identified by abnormal dendrite morphology and altered synaptic protein expression. Astrocyte secreted factors such as Tenascin C (TNC), may contribute to the synaptic changes, including maturation of the synapse. TNC is a known endogenous ligand of toll-like receptor 4 (TLR4) that has been shown to induce the expression of pro-inflammatory cytokines such as interleukin-6 (IL-6). At the molecular level, elevated IL-6 promotes excitatory synapse formation and increases dendrite spine length. With these molecular changes linked to the phenotype of FXS, we examined the expression and the mechanism of the endogenous TLR4 activator TNC, and its downstream target IL-6 in astrocytes from the FMR1 KO mouse model. Secreted TNC and IL-6 were significantly increased in FMR1 KO astrocytes. Exogenous TNC and lipopolysaccharide (LPS) stimulation of TLR4 induced secreted IL-6, whereas the antagonist of TLR4 (LPS-RS) had an opposing effect. Cortical protein expression of TNC and IL-6 were also significantly elevated in the postnatal FMR1 KO mouse. These results identify TNC as an endogenous ligand of TLR4, capable of effecting IL-6 secretion by astrocytes. In addition, there was an increase in the number of VGLUT1/PSD95 positive synaptic puncta of both WT and FMR1 KO neurons when plated with astrocyte conditioned media from FMR1 KO astrocytes, compared to those plated with media from wild type astrocytes. By assessing the cellular mechanisms involved, a novel therapeutic option could be made available to target abnormalities of synaptic function seen in FXS.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
Autism spectrum disorders (ASDs) are neurodevelopmental disorders which arise from genetic and environmental factors. In the brain, a type of cell called the astrocyte is responsible for proper brain growth and development. Astrocytes release factors that promote inflammation, causing disruption of brain functions that control learning, memory and behaviour. Such factors released by astrocytes are capable of binding to their receptors, in turn impacting downstream targets, which have physiological effects.
This research used various biological and genetic techniques to determine if the mechanism of an astrocyte-specific factor called Tenascin C (TNC) is impaired in the Fragile X mouse model. In a normal astrocyte, TNC with its binding partner is able to release molecules responsible for inflammation. Such molecules have been shown to increase the number synapses, where neurons and astrocytes exchange information, to control brain function.
This proposed research would be the first to determine a role for TNC in ASDs. By assessing the cellular mechanisms involved between TNC and its binding partner, a novel therapeutic option could be made available in ASDs.


title: The Equatorial Pacific Carbon Model (EPCM)

contributor:
Kramer, J. R.
Takacs, Imre

subject:
equator
pacific
carbon model
carbon

abstract: A computer simulated model representing carbon dynamics within the eastern equatorial Pacific was developed. The three compartment model incorporated the physical, biological and chemical processes most significant to the region of study representing both "normal" and highly disruptive conditions. The events which interrupt the normal carbon dynamics are known as El Niño events. The most profound effects that the El Niño has on the eastern equatorial Pacific are anomalously high sea-surface temperatures and a weakening in the typically intense upwelling motion. It is during these periods that the equatorial Pacific has been thought as being a sink for carbon dioxide. The EPCM incorporated these extreme changes, as typified by sea-surface temperature and upwelling, in order to determine the levels of sensitivity of the model parameters to these adversive conditions. The EPCM suggests that variations in upwelling rates have a much greater effect on model parameters than a change in sea-surface temperatures. As well, it has been suggested that cooler temperatures limit zooplankton and phytoplankton parameters much more than warmer conditions. Lastly, it has been demonstrated that, according to the EPCM, the equatorial Pacific is always a source of carbon dioxide to the atmosphere. Net movement towards the atmosphere persists even during periods when upwelling is at its weakest, as simulated by the EPCM.

abstract: Thesis

abstract: Bachelor of Science (BSc)


title: Flow-Acoustics of T-Junctions: Effect of T-Junction Geometry

contributor:
Ziada, Samir
Mechanical Engineering

subject: flow-acoustics t-junction acoustic flow geometry

abstract: This study focuses on the mechanism of flow-acoustic coupling in a T-junction, which has a transitional section entailing an expansion of pipe diameter. Six cases with varying length of the transitional section have been tested. It is shown that T-junctions with transitional sections can be a strong source of acoustic excitation and therefore can cause powerful acoustic resonance in the associated piping systems. Elimination of the transitional section reduces the excitation level drastically. The length of the transitional section with enlarged diameter is found to be the fundamental length scale determining the Strouhal number of flow excitation in the T-junction. To investigate the mechanism further, a series of experiments were conducted in a rectangular pipe system, which was considered as the 2D case of the T-junction. The results showed that the vortices formed in the outer and inner sides of the T-junction are both acoustic sources. They appear to form independently without interaction with each other, but are synchronized by the acoustic field. Flow visualization was carried out to gain images of the flow pattern when the resonance occurs. The images from flow visualization provided support to the measurements of the rectangular pipe system. Numerical simulations of the mean flow and acoustic field in the rectangular T-junction were performed. A simplied analysis of acoustic energy generation was also carried out.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: CALCIUM TRANSPORT BY INSECT MALPIGHIAN TUBULES

contributor:
O'Donnell, Michael
Biology

subject: calcium Malpighian transport tubule Drosophila fly Acheta cricket Aedes mosquito Ca2+ insect homeostasis haemolymph SIET electrophysiology Ramsay transcellular channel concretion granule Ca-rich spherite ionoregulation

abstract:
Insects maintain blood (haemolymph) Ca2+ concentrations within a narrow range in order to support the health of internal tissues and organs. The Malpighian (renal) tubules play a primary role in haemolymph Ca2+ homeostasis by sequestering excess Ca2+ within calcified biomineral deposits (Ca-rich granules) often located within type I (principal) tubule cells. Using the classic Ramsay assay, the scanning ion-selective microelectrode technique (SIET), and modifications of these two electrophysiological techniques, this thesis begins to unravel the sites and mechanisms of Ca2+ transport by the Malpighian tubules isolated from eight insects, representing seven orders. A segment-specific pattern of Ca2+ flux was observed along the length of the Malpighian tubules isolated from D. melanogaster, A. aegypti and A. domesticus and was uniform along the length in the remaining species. The majority (≥ 90%) of Ca2+ entering the tubule cells is sequestered within intracellular calcium stores in Ca2+-transporting segments of D. melanogaster and A. domesticus tubules, consistent with the presence of Ca-rich storage granules in these tubule segments. In addition, this thesis provides the first measurements of basolateral Ca2+ flux across single principal and secondary tubule cells of T. ni, where Ca2+ uptake occurs only across principal cells. Perhaps the most important finding of this thesis is that increasing fluid secretion through manipulation of intracellular levels of cAMP or Ca2+ in isolated tubules of A. domesticus had opposite effects on tubule Ca2+ transport. The adenylyl cyclase-cAMP-PKA pathway promotes Ca2+ sequestration whereas both 5-hydroxytryptamine and thapsigargin inhibited sequestration. In contrast, tubules of the remaining species were generally insensitive to cAMP or thapsigargin and
v
rates of tubule Ca2+ transport were often very low. The presence of Ca-rich granules in the cells of the midgut in several of the species with low rates of tubule Ca2+ transport provide evidence for a putative role of the midgut in haemolymph Ca2+ homeostasis. Taken together, these results suggest that the principal cells of the Malpighian tubules contribute to haemolymph calcium homeostasis through neuroendocrine regulated sequestration of excess Ca2+ during periods of high dietary calcium intake. Sequestration of dietary Ca2+ by the midgut may reduce Ca2+ entry into the haemolymph and therefore Ca2+ sequestration by the Malpighian tubules need not be so rapid. Finally, reversible tubule Ca2+ transport may allow internal reserves of Ca2+ (Ca-rich granules) to be returned to the haemolymph allowing insects to survive prolong periods of Ca2+ deficiency (i.e. overwintering).

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: This thesis contributes to our understanding of how insects regulate the calcium content of their blood (haemolymph). Using electrophysiological techniques with improved spatial resolution (from millimeters to micrometers) this thesis sought to determine the sites, mechanisms and regulation of Ca2+ transport by insect Malpighian (renal) tubules in order to gain insights into the role of Ca-rich granules (similar to those identified in early stages of human kidney stone formation i.e. nephrolithiasis) within these tissues. Using eight insect species this thesis demonstrates that the Malpighian tubules act as dynamic Ca2+ stores that appear to be under neuroendocrine control: actively taking up Ca2+ through calcium entry channels, where the majority (≥ 90%) of excess haemolymph Ca2+ is sequestered within intracellular stores (Ca-rich granules) during period of excess dietary calcium and passively releasing Ca2+ back to the haemolymph during periods of metamorphosis or calcium deficiency (i.e. overwintering).


title: Understanding Syrian Refugee Adolescents’ Conceptualizations of Mental Health

contributor:
Wahoush, Olive
Global Health

subject:
Mental Health
Adolescents
Syrian Refugee
Conceptualization

abstract: Background: Since 2011, there has been ongoing conflict in Syria, resulting in the displacement of over 11 million people. Over 40,000 Syrian refugees resettled to Canada and of that, 52% were under the age of 19, falling into the adolescent age group. Adolescence (ages 10-19) is a critical stage for physical, psychosocial and cognitive development. As a result, mental health challenges often first emerge during adolescence. Refugee adolescents are a particularly vulnerable group, as normal adolescent stress is compounded with resettlement stress. Further research is needed to understand how Syrian refugee adolescents conceptualize mental health so that their needs can be better addressed. Methods: Data was collected using semi-structured interviews with older Syrian refugee adolescents (n=7) and service providers (n=8) in the Greater Toronto Area. Interviews were recorded and transcribed verbatim. Data analysis was guided by grounded theory. Results: The findings indicate that conceptualizations of mental health are highly dependent on how the concept is framed. The term mental health was poorly understood amongst Syrian adolescents. However, when different terms were used to describe mental health, including stress, pressure and comfort, it was clear that adolescents had a much deeper understanding of the concept. Once appropriate mental health framing was employed, adolescents were able to identify factors that they believed influence mental health status. Factors identified by adolescents and service providers included individual, social and system-level factors. Conclusions: Syrian adolescent perspectives are crucial in fully understanding their conceptualizations of mental health. The comparison of adolescent and service provider perspectives allowed for a comprehensive understanding of adolescent mental health, while identifying differences in perspectives between the two groups. This study recommends future strategies for policy makers, service providers and researchers to effectively address Syrian adolescents’ mental health.

abstract: Thesis

abstract: Master of Science (MSc)


title: Visual Regulation of Manual Aiming

contributor:
Elliott, Digby
Human Biodynamics

subject:
regulate
visual
manual aim
manual

abstract: Traditional models of visuomotor control have generally emphasized the importance of vision in the guidance of limb movements. Vision is thought to subserve the modificational processes underlying the control of these movements. The objectives of the present work were to elaborate upon the role of vision in the regulation of an ongoing limb movement, address issues pertaining to the nature of this regulation, and examine predictions of the Optimized Submovement Model (Meyer, Abrams, Kornblum, Wright, & Smith, 1988) of limb control. An aiming task was adopted in which subjects were required to displace a graphics cursor on a monitor toward a target. The presence of visual feedback proved to be a potent determinant of performance. In Experiment 1, superior performance consistency with visual feedback was attributable to the prevalence of discrete and continuous modifications made to the movement when visual information was available. In Experiment 2, the same visually-based performance advantage was found. However, this advantage was no longer related to the presence of adjustments to the movement. The present results are discussed with reference to current issues in the nature of visuomotor regulation and their implications toward the Optimized Submovement Model.

abstract: Thesis

abstract: Master of Science (MS)


title: Modelling and Control of an Omni-directional UAV

contributor:
Sirouspour, Shahin
Electrical and Computer Engineering

subject: UAV, Control Systems, Fully-actuated, omnicopter, quadcopter, attitude control, energy optimal control, system identification, airflow model

abstract:
This thesis presents the design, modeling, and control of a fully-actuated multi-rotor unmanned aerial vehicle (UAV). Unlike conventional multi-rotors, which suffer from two degrees of underactuation in their propeller plane, the choice of an unconventional propeller configuration in the new drone leads to an even distribution of actuation across the entire force-torque space. This allows the vehicle to produce any arbitrary combination of forces and torques within a bounded magnitude and hence execute motion trajectories unattainable with conventional multi-rotor designs.

This system, referred to as the \omninospace, decouples the position and attitude controllers, simplifying the motion control problem. Position control is achieved using a PID feedback loop with gravity compensation, while attitude control uses a cascade architecture where the inner loop follows an angular rate command set by the outer attitude control loop.

A novel model is developed to capture the disturbance effects among interacting actuator airflows of the \omninospace. Given a desired actuator thrust, the model computes the required motor command using the current battery voltage and thrusts of disturbing actuators. A system identification is performed to justify the use of a linear approximation for parameters in the model to reduce its computational footprint in real-time implementation.

The \omni benefits from two degrees of actuation redundancy resulting in a control allocation problem where feasible force-torques may be produced through an infinite number of actuator thrust combinations. A novel control allocation approach is formulated as a convex optimization to minimize the \omnis energy consumption subject to the propeller thrust limits. In addition to energy savings, this optimization provides fault tolerance in the scenario of a failed actuator.

A functioning prototype of the \omni is built and instrumented. Experiments carried out with this prototype demonstrate the capabilities of the new drone and its control system in following various translational and rotational trajectories, some of which would not be possible with conventional multi-rotors. The proposed optimization-based control allocation helps reduce power consumption by as much as 6\%, while being able to operate the drone in the event of a propeller failure.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Endurance Exercise Training Attenuates Leucine Oxidation and Branched-Chain 2-Oxo Acid Dehydrogenase Activation During Exercise in Humans

contributor:
Tarnopolsky, Mark
Human Biodynamics

subject:
endurance
exercise
leucine
oxidation
2-oxo acid
dehydrogenase
humans

abstract:
Endurance exercise has been shown to both raise and lower leucine oxidation in studies in rodents. We studied the effects of a 38 d endurance exercise training program upon leucine turnover during a 90 min exercise bout at 60 % VO_2peak in 6 males and 6 females. Subjects were studied at both the same absolute (ABS) and relative (REL) exercise intensities post-training. Pre (PRE)- and post-training measurements were taken
for analysis of: L-[1-^13C]leucine turnover, muscle branched-chain oxoacid dehydrogenase activity (BCOAD), muscle glycogen, phosphocreatine and ATP utilization, and resting enzyme activity of citrate synthase (CS) and NADH-cytochrome c-oxidoreductase (complex I-III). We also determined total substrate oxidation by indirect calorimetry, and plasma lactate, glucose, and insulin concentrations. The exercise training resulted in a significant increase in both CS (P < 0.001) and complex I- III (P < 0.05) activities. Leucine oxidation increased during exercise for the pre-training trial (P < 0.001), however, there was no increase for either the post-training ABS or REL trial. Leucine oxidation was significantly lower for females at all time points (P < 0.01). Total BCOAD activity was also significantly increased when comparing the PRE to both ABS and REL
trials (P < 0.001). The % activation of BCOAD was significantly increased from t=0 to t=90 in both the PRE and REL exercise trials with the increase in PRE being greater (P < 0.001 (PRE), and P < 0.05 (REL)). Exercise RER was lower for females vs. males (P< 0.05). In addition, the ABS trial was significantly lower than PRE and REL (P < 0.01). Plasma lactate was significantly lower at all time points for ABS vs. PRE (P < 0.001) and
REL vs. PRE at t=30 min of exercise (P < 0.001). Resting muscle glycogen was higher for both ABS and REL vs. PRE (P < 0.001). In conclusion, we found that 38 d of endurance exercise training significantly attenuated both leucine oxidation and BCOAD activation during 90 min of endurance exercise at 60 % VO_2peak for both absolute and relative exercise intensities. In addition, females were also shown to oxidize a greater proportion of energy from lipid and a lesser amount from carbohydrates and proteins during exercise.

abstract: Thesis

abstract: Master of Science (MS)