title: Energy Harvesting of Infrared Radiation Using Dual-Polarized Nanoantennas

contributor:
Bakr, Mohamed
Howlader, Matiar
Ali, Shirook
Electrical and Computer Engineering

subject:
Nanoantennas
Infrared
Energy Harvesting
Dual-Polarized

abstract: In this research work, we propose a novel energy harvester which converts solar electromagnetic radiation into DC energy at infrared regime. The proposed device consists of a dual polarized nanoantenna loaded with an anisotropic material at its gap.  The dual polarized nanoantenna focuses the randomly polarized radiation into its gap resulting in high electric field. This high local electric field at the gap interacts with the anisotropic material. In our proposed design, the anisotropic material possesses nonlinear electrical conductivity and converts the dual polarizations at the gap into a DC voltage difference across the terminals of the nanoantenna. The novelty of our proposed design is in the rectification of the electromagnetic radiation without utilizing a diode. The theory of the energy harvester depends on the utilization of the dual polarized nanoantennas at high frequency regime. Therefore, we carry out a parametric study to investigate the resonance characteristic of the dual polarized nanoantenna. In addition, we investigate the effect of the geometrical parameters on the local field enhancement at the gap of the dual polarized nanoantenna. Also, another parametric study is carried out to determine the effect of the governing parameters of the anisotropic material on the generated DC voltage across the harvester. Our approach is illustrated through electromagnetic simulations.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The Effect of Gap Distance on the Heat Transfer Between a Finned Surface and a Porous Plate

contributor:
Ching, C.Y.
Ewing, D.
Mechanical Engineering

subject: gap distance, heat transfer, finned surface, porous plate, capillary evaporator, heat fluxes

abstract:
 Experiments were performed to investigate the effect that a gap between a heated fin and a porous plate has on the heat transfer performance of a simulated capillary evaporator. The heat transfer performance was examined for two porous plates with average pore radii of 50 and 200 μm respectively. Tests were performed for gap distances between 0 and 900 μm and heat fluxes ranging from 17 to 260 kW/m^2. The heat transfer performance of the simulated capillary evaporator initially increased as the gap distance was increased. However, a further increase in the gap distance caused a decrease in performance. The maximum heat transfer performance occurred at a smaller gap distance for the plate with the smaller pore radius. For small gap distances, persistent high temperature regions were observed on the surface of the heated foil that grew and became more frequent at higher heat fluxes. For larger gap distances, saturated regions that appeared on the foil at moderate heat fluxes suggest that microlayer evaporation may be taking place within the gap. At high heat fluxes, these saturated regions are no longer present, but the temperature of the heated foil remained stable.

 The heat transfer process in the porous media was examined using thermocouples embedded within the porous plates. These temperature measurements indicate that a two phase region forms within the porous plate for a pore radius of 200 μm. Little evidence of vapour was observed within the plate with a pore radius of 50 μm. In that case, there was more evidence of vapour present at the surface of the porous plate. There was less evidence of vapour at the surface of the porous plate for the larger gap distances,
suggesting that the vapour escapes more easily through the gap at larger gap distances.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Overcoming Limitations in Adoptive Cell Therapies with Dual Specific T-cells and Oncolytic Viral Boosting

title: Bastin_Donald_J_2017Sept_MSc

contributor:
Wan, Yonghong
Medical Sciences

subject:
Oncolytic Virus
Adoptive Cell Thearpy
Immunotherapy
Cancer

abstract:
The adoptive transfer of cancer-specific T-cells has demonstrated success as a novel treatment strategy in some hematological malignancies but this approach has not yet achieved widespread curative potential in the majority of tumors. To circumvent many of the limitations currently facing adoptive cell therapies, our lab has recently developed a combination therapy involving the in vivo boosting of adoptively transferred tumor-specific memory T-cells with an oncolytic viral vaccine. While this represents a demonstrably powerful approach in preclinical models of cancer it is limited by its targeting of a single antigen. Therapeutic resistance is a common concern when targeting a single antigen or pathway and an ideal therapy would include built-in mechanisms to address the heterogeneity and mutability that is inherent to cancer. Thus the focus of this research involved the development of a strategy to target therapeutic resistance in the context of the adoptive cell transfer with oncolytic viral boost regimen.
In order to address the single antigen limitations, the engineering of tumor-specific T-cells with a targeting capacity for a second antigen is described. In addition to their endogenous tumor target it is shown that these cells have specificity for and can kill cells expressing ligands for the natural killer group 2 member D receptor which are commonly upregulated on both cancer cells and components of the tumor microenvironment.  Indeed it is demonstrated in an in vivo model of relapse that T-cells capable of targeting both antigens produce more consistent and prolonged remissions than those with only their endogenous targeting capacity. Furthermore pharmacological strategies for the enhancement of engineered T cell survival and efficacy are also described. Finally the early development of a chimeric tumor model to further characterize the potential of dual-specific T-cells to address tumor heterogeneity is presented.

abstract: Thesis

abstract: Master of Science (MSc)


title: Design, Modeling and Simulation of Planar Waveguide Optical Splitter

contributor:
Li, Xun
Electrical and Computer Engineering

subject: design, modeling, simulation, planar waveguide, optical splitter

abstract:
 1-by-N optical power splitters are primary components in the field of integrated optics and optical transmission systems. Planar waveguide optical power splitters are key devices to realize low-cost optical transmission systems through photonic integration. The goal of this thesis is to design, model and simulate a novel planar waveguide optical power splitter for optical transmission systems and Fiber to the Home (FTTH) networks.

 The first chapter is an introduction. This chapter gives the background of power splitter, reviews the existing devices and explains why our novel design is needed.

 The idea of this novel power splitter is presented in Chapter 2, including analytical formulations, theoretical calculations and designs. This serves as a theoretical foundation for the development and verification of different parts presented in Chapter 3. The novel power splitter design is composed of a series of waveguide lenses and waveguide phase shifts. The analytical formulations are derived and intensive numerical simulations are performed to verify and
investigate this new power splitter. Also the conventional Beam Propagation Method (BPM) is studied in this chapter, which provides a numerical preparation for the device simulation and design in the subsequent chapter.

 The design results are shown in Chapter 4. The novel power splitter design predicts good performance with more compact device size, better output and smaller wavelength dependence. This chapter demonstrated the possibility of new power splitter working as a better approach to the existing MMI or other structures.

 Finally, Chapter 5 gives a conclusion to this thesis. The limitations of this work are presented and the future works are proposed.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Development of an in vitro Relapse Model for Identification of Novel Therapeutics in Acute Myeloid Leukemia

title: Development of an in vitro Relapse Model for AML

contributor:
Bhatia, Mick
Biochemistry and Biomedical Sciences

subject:
Acute Myeloid Leukemia
Relapse
Therapeutic Resistance
In vitro Modeling

abstract:
AML is a cancer of the blood and bone marrow characterized by the presence of
highly proliferative and abnormally differentiated myeloblasts. Previous work from the
Bhatia lab utilized the orthotopic xenograft model in order to isolate a population of
leukemic regenerating cells (LRC) that exists prior to relapse. Affymatrix analysis of LRCs
revealed up-regulation of 248 genes that can act as unique targets to prevent relapse. In
order to screen compounds against all 248 targets, it is important to develop an in vitro
model that is able to appropriately recapture the functional and molecular markers of
LRCs. Primary AML samples were treated with 5-doses of 0.15 μM, 1 μM AraC, or DMSO
control and several outcomes were measured. In vitro AraC treatment was not able to
recapitulate the progenitor frequency curve and CD34 expression curve observed in vivo.
Additionally, we were not able to see a consistent increase in select LRC targets DRD2,
GLUT2, FUT3, and FASL via flow cytometry. Despite an increase in the mRNA levels of
LRC genes 24h after treatment with 0.15 μM AraC, long term analysis could not be
completed due to poor RNA quality and low expression of LRC-targets. Primary AML cells
were co-culture with mouse MS-5 stromal cell line order to study the effects of
mesenchymal stromal cells on AML response to AraC. Co-culture with MS-5 cells had
different effects on select primary AML cells. AML 14939 showed an increase in CD34
and LRC targets DRD2 and FUT3 following AraC treatment when co-cultured with MS-5
cells; while A374 showed no differences between DMSO and AraC treated groups.
Overall, these findings suggest the LRC signature is not induced by treatment with AraC
alone. Complex interactions between AML cells and their bone marrow niche during AraC
treatment plays an important role in the development of LRCs prior to AML relapse.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
AML is a cancer of blood cells characterized by the presence of rapidly dividing
cancer cells termed myeloblasts. AML has a high rate of disease relapse. The Bhatia lab
modelled AML relapse in a mouse and discovered an unique population of cells that exist
prior to relapse termed LRCs. LRCs express distinctive genes that can act as targets for
the development of new therapies to prevent relapse. In order to screen potential relapse preventing compounds, we set out to recapture AML relapse using cells in a dish. AML
cells from patients were treated with chemotherapy reagent AraC and the number of
cancer progenitors and the expression of specific LRC proteins were measured. AraC did
not increase the level of 3 out of 4 LRC proteins studied. We determined the LRCs were
not caused by AraC treatment, and the physiology of the bone marrow environment plays
an important role in inducing relapse.


title: A Critical Discourse Analysis of Canada's Throne Speeches Between 1935 and 2015

contributor:
Fudge Schormans, Ann
Social Work

subject:
discourse analysis
speeches from the throne
government discourse
social welfare and neoliberalism

abstract: The purpose of this thesis was to uncover the tools of manipulation used within political discourses by governments in their attempt to maintain power in society. It specifically asked, How do Canadian federal governments manipulate security, risk, and threat discourses alongside their presentation and understanding of Canadian identity in throne speeches to justify the direction they intend to take the country in with their mandate? This thesis used Critical Discourse Analysis methods to analyze fourteen federal majority government speeches from the throne during the rise and fall of social welfare in Canada. Findings highlight that governments have relatively consistently used the combination of security, risk, and threat discourses between 1935 and 2015. Canadian identity has also been shown to be malleable to government priorities, being connected to notions of collectivism during the rise of social welfare and individualization and productivity during the implementation of neoliberal principles. The introduction of the promise of job creation within the speeches was found to correlate with the introduction of neoliberal principles in Canada. These findings highlight the importance of critical understanding of dominant discourses in society in order to overcome the power they can impose over non-dominant groups.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Écriture kurde en français: Territoire, identité et discours

contributor:
Nshimiyimana, Eugène
French

subject: Écriture kurde en français

abstract:
This thesis, consisting of four chapters, presents an innovative perspective on the strategies used by French-speaking Kurdish authors to convey their claims and aspirations. The first chapter deals directly with the linguistic question, the general objective being to raise the main political and aesthetic issues involved in writing in a dominant language from a minority perspective. The second chapter focuses on the question of identity and illustrates how the experience of French-speaking Kurdish writers can serve as a basis for establishing a minority perspective on society. The third chapter examines the question of the access to speech and identifies the sociopolitical consequences of the voice of the marginalized on the assertion of identity. The aim of this study is to examine in depth the literary and discursive strategies, such as testimony, that are privileged by writers from a dominated culture to get recognition of the subjectivity of these peoples who are excluded from knowledge. The last chapter is an analysis of two other literary and discursive tactics allowing the subjectivity of the marginalized to build, showing how the unsaid or unspoken and irony are tools of an oppositional writing in the invocation of an alternative discourse that destabilizes the discourse of power. The works of the French-speaking Kurdish writers reveal a minority perspective of identity in a context of oppression and domination, and thus produce a “unique” expression of the experience of otherness and power.
Keywords: Kurdish writing in French, territory, identity, discourse, testimony, opposition

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The main objective of this study is to evaluate the issues related to the use of another language on the assertion of the identity of dominated or oppressed societies. The voice of French-speaking Kurdish writers is of particular interest to this objective. The secondary objective of our research is to highlight the relationships between territory, identity and discourse. This concern is due to the fact that the fate of the Kurdish community, as depicted by the authors of the corpus, is perpetually compromised by Middle Eastern and Western political powers.


title: Characterizing the Particle-Particle and Particle-Polymer Interactions that Control Cellulose Nanocrystal Dispersion

contributor:
Cranston, Emily
Chemical Engineering

subject:
Cellulose
Cellulose nanocrystals
Dispersion
Particle interactions
Polymer adsorption
Nanocomposites
Surface plasmon resonance
Benchmarking
Thin films
Swelling
Atomic force microscopy
Quartz crystal microbalance

abstract: With the aim of developing a deeper understanding of particle behaviour within nano-hybrid materials, this thesis investigates the particle-particle and particle-polymer interactions that influence and control cellulose nanocrystal dispersion in aqueous and non-aqueous environments.

abstract: Cellulose nanocrystals (CNCs) are rigid rod-shaped nanoparticles derived from bio-based resources and are considered an emerging nanomaterial based on their commercial availability and favourable properties. CNCs have great potential as reinforcing agents in hybrid materials and composite applications if they are well-dispersed. Whereas colloidal stability is effectively described by established theories, dispersing nanoparticles from an aggregated state, and their interaction with polymers can be difficult to predict and control. Herein, the particle-particle and particle-polymer interactions that govern CNC dispersibility in aqueous and non-aqueous environments are examined. The surface chemistry, morphology and colloidal/thermal stability of CNCs from North American industrial producers were extensively characterized such that particle interactions could be reproducibly measured from a known starting material. Industrially produced CNCs compared well to those produced at the bench-scale, implying that laboratory results should be translatable to the development of new CNC-based products. To examine particle-particle interactions within dry CNC aggregates, a surface plasmon resonance-based platform was developed to monitor CNC film swelling in a range of solvents and salt solutions. Water was observed to interrupt particle-particle hydrogen bonding most effectively, however film stability, and ultimately particle aggregation, was maintained by strong van der Waals interactions. Moreover, particle spacing and overall film thickness was found to be independent of the CNC surface chemistries and surface charge densities examined, yet the rate of film swelling scaled with the ionic strength of the surrounding media. Polyethylene glycol (PEG) was used as a model, non-ionic, water-soluble polymer to investigate polymer adsorption to CNC surfaces in water. PEG did not adsorb to CNCs despite the abundance of hydroxyl groups, which is in direct contrast to silica particles that are well known to hydrogen bond with PEG. Combining the knowledge of both particle-particle and particle-polymer interactions, PEG nanocomposites reinforced with CNCs and silica were compared and particle dispersibility was related to composite performance. Although PEG does not adsorb to CNCs in aqueous environments, polymer adsorption does occur in dry polymer nanocomposites leading to good dispersibility and improved mechanical properties. Overall, the work presented here yields new insight into the forces that govern CNC dispersion and provides a foundation from which a variety of new CNC-based products can be developed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Using particles derived from renewable resources to reinforce plastics and other materials has the potential to make products lighter, stronger and more environmentally friendly. However, to make these products we need to understand how to control and distribute particles uniformly throughout hybrid/composite materials. This work uses particles extracted from trees and cotton, known as cellulose nanocrystals, to reveal which factors govern particle dispersion in reinforced composite materials. To do so, first the properties and performance of commercially available cellulose nanocrystals were extensively analyzed and compared to form the basis from which interactions can be understood. Next, particle films were measured in water, organic solvents and salt solutions to better understand how aggregated cellulose nanocrystals can be separated within composite materials. The interactions between water-soluble polymers and cellulose nanocrystals were then investigated to reveal how polymer adsorption impacts particle dispersibility. Finally reinforced polymer composites were prepared with uniformly distributed cellulose nanocrystals and the crystallization and mechanical properties were investigated. By developing a deeper understanding of the factors that control cellulose nanocrystal dispersion we can learn how to make a variety of new and improved environmentally conscious products.


title: A Spring Thaw? Political Advocacy in Post-Audit Canada

contributor:
Baker Collins, Stephanie
Social Work

subject:
Charitable Status
Political Activity
Advocacy
CPS-022
10 percent policy

abstract:
Despite having expertise on the day to day consequences of how individuals and groups are impacted by the policies and decisions of governments, charities have experienced a great deal of tension in their attempts to influence public policy. The CPS-022 Policy Statement that restricts the political activity of charities to 10 percent of their overall budget has been identified as confusing, antiquated, and not in line with the advocacy role that some charities identify as necessary for social change. These tensions were further exacerbated by the political activity audit program which was enacted by the Harper government from 2012-2015. This program caused an advocacy chill that was felt to varying levels by different charities in the sector. The purpose of this research is to explore how the CPS-022 interacts with everyday practice as it pertains to advocacy, gauge whether or not there has been a warming to the advocacy chill, and to collect senior employee’s impressions regarding the proposed recommendations for changes to the CPS-022 collected by a consultation panel.
	Semi structured qualitative interviews were completed with 6 participants from macro-based social organizations in Ontario. Participants shared their opinions and experiences of audit, governmental control of the social agenda, working within the policy statement, and the panel’s recommendations for change. Using a structural social work lens to analyze the data, it was found that a lack of clarity and a broad scope of interpretation within the CPS-022 made advocacy more daunting, participants were not concerned about exceeding the 10 percent limit, and there has been a variable warming to the advocacy chill. Participants were generally happy with the recommendations laid out by the panel, despite a lack of focus on clarifying partisanship, and the potential for broadness in the legislation. Overall, it became obvious that the charitable sector is in a period of transition and growth with regard to their role in public policy development.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Living with Ambiguity: The Strategies of Tongzhi’s Negotiation with Their Sexual Identities in Globalizing China

contributor:
Y. Rachel, Zhou
Social Work

subject:
Chinese Tongzhi
globalized queer culture
family kinship system
negotiation strategies

abstract: I argue that Xing hun (Contract marriage)” and “Coming out with Chinese characteristics” are creative and feasible approaches for Chinese Tongzhi (queer) from the perspective of vertical historical development. My study is a critical intercultural examination of the western-centric in dominant queer discourse. I discussed the non-confrontational communication practices which are different from the western confrontational practices (visibility & sexuality identity).

abstract: Transnational forces in the processes of globalization have determined the identities of the Chinese queer population. This thesis aims to explore how global capitalism, information and communication technology, and international collaboration in dealing with HIV and AIDS have facilitated the spread of western queer discourses and ideologies to China, and how these forces have influenced the construction of Chinese Tongzhi/queer identities. I use the discourse analysis to argue that the western norms of queer “coming out” and “declaring identity” can be an action accompanied by risk in the Chinese social, cultural, and political contexts, given that homosexual desires have challenged the institutions--not just sexuality but also marriage and family-- of heteronormativity. Chinese Tongzhi have to deal with the tension between Chinese traditional norms and western queer culture by negotiating some complex and dynamic strategies for defining their sexual identities. These strategies include “keeping silent about one’s sexual identity, or not coming out” and “having xinghun (contract and fake marriages with opposite-sex individuals.)” as a compromise between their traditional family obligations and homosexual desires in order to be able to live a “tolerable” queer life. I conclude that the strategies of the Chinese Tongzhi illustrate the agency of Chinese queers in creating a feasible space in which to live with their sexual identities and the process of globalized queer culture in a specifically Chinese context.

abstract: Thesis

abstract: Master of Social Work (MSW)

abstract: This thesis aims to explore how global capitalism, information and communication technology, and international collaboration in dealing with HIV and AIDS have facilitated the spread of western queer discourses and ideologies to China, and how these forces have influenced the construction of Chinese Tongzhi/queer identities.Chinese Tongzhi has to deal with the tension between traditional Chinese norms and western queer culture by negotiating some complex and dynamic strategies for defining their sexual identities.


title: Towards Identifying Disinfectants and Quantifying Disinfectant Levels in Water

contributor:
Kruse, Peter
Chemistry and Chemical Biology

subject:
Disinfectant
Water Quality
Redox molecule
Chemiresistor
Free chlorine
Disinfectant monitoring
Carbon nanotube

abstract:
Disinfectants are added to the water distribution system and swimming pools to
control the growth of pathogenic microorganisms in water. High disinfectant levels are
health hazards since they produce disinfectant by-products which are carcinogens. Thus,
monitoring the amount ofresidual disinfectants present and maintaining an optimal amount
of residual disinfectants throughout the distribution network is very crucial for safe water
distribution. Colorimetric measurements are the current standard for measuring disinfectant
levels in water. However, it is very difficult to integrate colorimetric measurements into
automated monitoring devices. Redox active molecules like the phenyl-capped aniline
tetramer (PCAT) can be incorporated as a dopant into a single wall carbon nanotube sensor
for detecting oxidant in drinking water. The sensor works on the principle of oxidizing
adsorbed redox molecules on carbon nanotubes by oxidant present in drinking water thus
changing the resistivity of the carbon nanotube film. Most commonly used disinfectants are
HOCl, Cl2, ClO2, Chloramine, KMnO4, HOBr, H2O2, O3, Br2, I2, etc. They all are oxidizing
agents and can be distinguished from one another as they have different oxidation potentials.
For water treatment purposes, it is not enough to know the disinfectant level, but it is also
very important to identify which disinfectant is present. Currently, there is no standard
method for distinguishing different disinfectants presents in water. The development of
sensor arrays based on redox active molecules having different redox potentials is a
potential pathway towards differentiating between different disinfectants in water.
Different aniline oligomers were synthesized to create a library of redox active molecules.
Redox properties of these molecules have been determined, and expected results were
compared with the sensor performance. In the future, these sensors can be incorporated into
a reliable, resettable and reagent free sensor array for monitoring and distinguishing
different disinfectants in water. Being able to constantly monitor the disinfectant level and
identifying the disinfectant present in water will enable us to design an improved and
sustainable disinfecting system.

abstract: Thesis

abstract: Master of Science (MSc)


title: Effects of early-life ionizing radiation exposure on the life-history of the cricket, Acheta domesticus

contributor:
Rollo, Christopher David
Biology

subject:
ionizing radiation
life-history
oxidative stress
early-life stress
insect
hormesis
phenotypic plasticity
cricket
dose-response
linear-no-threshold
tradeoff
reproduction

abstract:
Stressful experiences in early life can have profound and lasting impacts on phenotypic development. In anthropogenic environments, organisms are increasingly exposed to evolutionarily novel stressors that may play a major role in shaping the phenotypic variation upon which natural selection acts. For instance, ionizing radiation persists in areas affected by nuclear reactor accidents, nuclear weapons testing, and the nuclear power production process. This thesis explored the dose-response effects of early life ionizing radiation exposure on life- history traits in the cricket (Acheta domesticus L.). Specifically, this work had two goals: (1) to examine the effects of early life radiation stress on the potential tradeoff between growth and self-maintenance, and (2) to explore the dose-dependent effects of juvenile radiation exposure on adult trait expression (particularly fecundity, offspring investment, and offspring fitness).
It was found that exposure to moderate doses of radiation in early development resulted in a slower juvenile growth rate but increased survival in early adulthood, suggesting that self- maintenance was prioritized over growth. Despite the strong inhibitory effects of early life radiation on adult female body mass, age-specific fecundity was negatively impacted only at relatively high radiation doses. Crickets exposed to moderate radiation doses in early development laid larger eggs in adulthood relative to controls and these eggs had a greater hatching success, suggesting that radiation exposure had transgenerational effects on offspring performance. No noticeable effects of early life radiation exposure were detected on total and non-enzymatic antioxidant capacity or hydrogen peroxide levels in adult females. Together, this research indicates that a single, acute exposure to ionizing radiation in early life can affect phenotypic development in a complex, dose-dependent manner and that rather than being purely negative, phenotypic responses can be sustained or even enhanced.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
Stressful experiences in early life can have lasting impacts on organismal development, but the extent to which early life stress is harmful is unclear. In human-dominated environments, pollutants such as ionizing radiation can be a significant form of developmental stress. This thesis explores the fitness-related effects of early life ionizing radiation exposure in the
cricket, Acheta domesticus. Impacts on growth, longevity, fecundity, and offspring fitness are explored. This research indicates that early life stress can affect phenotypic development in a complex, dose-dependent manner and that rather than being purely negative, responses can be sustained or even enhanced.


title: Effects of Botulinum Toxin Treatment in Non-ambulatory Children and Adolescents with Cerebral Palsy: Understanding Parents’ Perspectives

title: Parents' Perspectives on Botulinum Toxin Treatment

contributor:
Gorter, Jan Willem
Rehabilitation Science

subject: botulinum toxin A

subject: cerebral palsy

subject: family-centred care

subject: international classification of functioning, disability and health

subject: qualitative research

subject: interpretive description

abstract:
Children and adolescents with cerebral palsy (CP) often receive botulinum toxin (BoNT-A) to
manage spasticity. Our 2014 study developed an inventory of parents’ goals for BoNT-A treatment, but reasons for selecting these goals were unclear. The current study aimed to describe and categorize the effects of BoNT-A that parents observed according to WHO’s International Classification of Functioning, Disability and Health (ICF) framework. This qualitative study used interpretive description. Fifteen parents of non-ambulatory young people with CP (mean age 10.2 years, SD 3.9, 7 males) who received BoNT-A were recruited through McMaster Children’s Hospital’s Spasticity Management Clinic. Interviews were conducted in-person or by telephone for 20-60 minutes. The research team read the initial transcript, identified codes, and finalized the coding framework. Member checking was conducted to enhance trustworthiness. The key theme was that parents needed to find the right path to do what is best for their child. Parents described how they learned about both positive and negative effects of BoNT-A treatment: some parents emphasized the child’s pain during BoNT-A injections (negative), but also felt that BoNT-A was helpful for their child (positive). Most effects of BoNT-A were coded at the ICF activity level, such as dressing These observations helped inform parents’ decision to continue with BoNT-A and identify future goals. This study provides insight into parents’ journey of learning about BoNT-A and goal-setting for their child. Parents’ perspectives will be used to refine the 2014 inventory of goals to facilitate collaborative goal-setting for BoNT-A treatment.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
Children diagnosed with cerebral palsy (CP) receive botulinum toxin (BoNT-A) as a treatment to
reduce muscle tone. Current research on the use of BoNT-A injections in non-ambulatory
children with CP is scarce and may not incorporate the perspectives of the family about their
goals for treatment. This study interviewed parents to ask about the effects that they observed in their child after BoNT-A treatment. Fifteen parents were interviewed and all parents spoke about their journey of “finding the right path to do what is best for my child” as they learned about the possible effects of BoNT-A treatment for their child. By learning about parents’ journey, informational resources can be developed and shared with other parents about the effects of BoNT-A treatment. It is important to help parents understand these effects, which would allow them to discuss and identify appropriate goals with healthcare professionals in future BoNT-A treatment sessions.


title: Surface Modification of Model Silicone Hydrogel Contact Lenses with Densely Grafted Phosphorylcholine Polymers

contributor:
Sheardown, Heather
Biomedical Engineering

subject: Atom Transfer Radical Polymerization

subject: Phosphorylcholine

subject: Silicone Hydrogel Contact Lenses

subject: Anti-fouling

subject: Tear Film

subject: 2-Methacryloyloxyethyl Phosphorylcholine

abstract:
When a biomaterial is inserted into the body, the interaction of the surface with the
surrounding biological environment is crucial. Given the importance of the surface, the ability to
alter the surface properties to support a compatible environment is therefore desirable. Silicone
hydrogel contact lenses (CL) allow for improved oxygen permeability through the incorporation
of siloxane functional groups. These groups however are extremely surface active and upon
rotation, can impart hydrophobicity to the lens surface, decreasing lens wettability and increasing protein and lipid deposition. Lens biofouling may be problematic and therefore surface
modification of these materials to increase compatibility is exceedingly recognized for
importance in both industry and research. The current work focuses on the creation of a novel anti-fouling polymer surface by the incorporation of 2-methacryoyloxyethyl phosphorylcholine (MPC), well known for its biomimetic and anti-fouling properties. A controlled polymerization method was used to generate a unique double-grafted architecture to explore the effect of increasing surface density of polyMPC chains on corresponding anti-fouling properties. The novel free polymer was synthesized by a 3-step atom transfer radical polymerization (ATRP). First, poly(2-hydroxyethyl methacrylate) (polyHEMA) was polymerized by ATRP, where the hydroxyl (OH) groups of the polymer then underwent an esterification to create macroinitiating sites. From these sites, a second ATRP of poly(MPC) varying in length occurred, yielding the double-grafted polymer poly(2(2-bromoisobutyryloxy-ethyl methacrylate)-graft-poly(2-methacryloyloxyethyl phosphorylcholine (pBIBEM-g-pMPC). The polymer was designed for resistance to protein adsorption through a possible synergistic effect between the surface induced hydration layer by surrounding PC groups coupled with steric repulsion of the densely grafted chains. To test its potential as a surface modifier, the polymer was grafted from model silicone hydrogel CL through a 4-step surface initiated ATRP (SI-ATRP) in a similar manner to the free polymer. First, the ATRP initiator was immobilized from the HEMA OH groups of the
unmodified CL, generating Intermedate-1. A polyHEMA brush was grafted from the initiating
sites yielding pHEMA-50, followed by the generation of a second initiator layer (Intermediate-
2). A sequential ATRP of poly(MPC) then generated the target pMPC-50/pMPC-100 surfaces.
For the free pBIBEM-g-pMPC polymer analysis, 1H-NMR and GPC determined polymers formed with a predictable MW and low polydispersity (PDI). For surface grafting, using a sacrificial initiator, 1H-NMR and GPC indicated that the pHEMA-50 and pMPC-50/pMPC-100 polymers were well-controlled, with a MW close to the theoretical and a low PDI. For surface chemical composition, ATR-FTIR showed the presence of the ATRP initiator (Intermediate-1 and 2) by the appearance of a C-Br peak and disappearance of the OH peak. XPS confirmed the chemical composition of the 4-step synthesis by a change in the fraction of expected surface elements. Both the surface wettability and EWC of the materials increased upon pMPC modification, further improving upon increasing pMPC chain length. The contact angle was as low as 16.04 ± 2.37º for pMPC-50 surfaces and complete wetting for pMPC-100. Finally, the single protein adsorption using lysozyme and bovine serum albumin (BSA) showed significantly decreased protein levels for pMPC-50/100 lenses, as much as 83% (p 0.00036) for lysozyme and 73% (p 0.0076) for BSA, with no significant difference upon chain length variation. The aforementioned data demonstrates that the novel polymer has potential in providing an anti-fouling and extremely wettable surface, specifically regarding silicone hydrogel CL surfaces.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: ASSOCIATION OF METFORMIN WITH BREAST CANCER INCIDENCE AND MORTALITY: A SYSTEMATIC REVIEW AND META-ANALYSIS

contributor:
Muti, Paola
Health Research Methodology

subject:
metformin
breast cancer

abstract:
Background Preclinical data suggests that metformin may have anti-cancer effects to reduce breast cancer incidence and improve cancer prognosis. However, the current evidence in observational studies is inconclusive. A systematic review and meta-analysis was conducted to assess the effect of metformin on the incidence and mortality of breast cancer in diabetic patients.

Methods A comprehensive literature search was performed on Medline (Pubmed), EMBASE, and the Cochrane library from inception to November 2016 with no language restrictions. Outcomes were incidence of breast cancer and all-cause mortality. Risk of bias and overall quality of evidence was assessed using the Newcastle Ottawa Scale and GRADE respectively. A meta-analysis was performed using the most adjusted odds ratios (ORs) or hazard ratios (HRs) and 95% confidence intervals (95% CI) as effect measures.

Results A total of 12 observational studies were included for breast cancer incidence and 11 studies for all-cause mortality. No significant association was found between metformin exposure and incidence of breast cancer (OR: 0.93, 95% CI: 0.85-1.03, I2 = 35%). A 45% risk reduction was observed for all-cause mortality (HR: 0.55, 95%CI: 0.44-0.70, I2=81%). Presence of publication bias is strongly suspected for both outcomes.

Conclusion The use of metformin in standard cancer therapy may improve overall survival of diabetic patients with breast cancer. No effect of metformin on the incidence of breast cancer was observed. Interpretation of results is limited by the observational nature of the studies and methodological biases. Clinical trials are warranted to determine the role of metformin in breast cancer risk reduction and prognosis.

abstract: Thesis

abstract: Master of Health Sciences (MSc)


title: Inference for Generalized Multivariate Analysis of Variance (GMANOVA) Models and High-dimensional Extensions

contributor:
Hamid, Dr. Jemila
Balakrishnan, Prof. Narayanaswamy
Mathematics and Statistics

subject:
Growth Curve Model (GCM)
GMANOVA models
Bayesian methods
High-dimensional data
Longitudinal analysis
Multivariate Skew Normal distribution
Extended Growth Curve Model (EGCM)
EM algorithm
Restricted EM algorithm
Matrix Newton Raphson method

abstract:
A Growth Curve Model (GCM) is a multivariate linear model used for analyzing longitudinal data with short to moderate time series. It is a special case of Generalized Multivariate Analysis of Variance (GMANOVA) models. Analysis using the GCM involves comparison of mean growths among different groups. The classical GCM, however, possesses some limitations including distributional assumptions, assumption of identical degree of polynomials for all groups and it requires larger sample size than the number of time points. In this thesis, we relax some of the assumptions of the traditional GCM and develop appropriate inferential tools for its analysis, with the aim of reducing bias, improving precision and to gain increased power as well as overcome limitations of high-dimensionality.

Existing methods for estimating the parameters of the GCM assume that the underlying distribution for the error terms is multivariate normal. In practical problems, however, we often come across skewed data and hence estimation techniques developed under the normality assumption may not be optimal. Simulation studies conducted in this thesis, in fact, show that existing methods are sensitive to the presence of skewness in the data, where estimators are associated with increased bias and mean square error (MSE), when the normality assumption is violated. Methods appropriate for skewed distributions are, therefore, required. In this thesis, we relax the distributional assumption of the GCM and provide estimators for the mean and covariance matrices of the GCM under multivariate skew normal (MSN) distribution. An estimator for the additional skewness parameter of the MSN distribution is also provided. The estimators are derived using the expectation maximization (EM) algorithm and extensive simulations are performed to examine the performance of the estimators. Comparisons with existing estimators show that our estimators perform better than existing estimators, when the underlying distribution is multivariate skew normal. Illustration using real data set is also provided, wherein Triglyceride levels from the Framingham Heart Study is modelled over time.

The GCM assumes equal degree of polynomial for each group. Therefore, when groups means follow different shapes of polynomials, the GCM fails to accommodate this difference in one model. We consider an extension of the GCM, wherein mean responses from different groups can have different shapes, represented by polynomials of different degree. Such a model is referred to as Extended Growth Curve Model (EGCM). We extend our work on GCM to EGCM, and develop estimators for the mean and covariance matrices under MSN errors. We adopted the Restricted Expectation Maximization (REM) algorithm, which is based on the multivariate Newton-Raphson (NR) method and Lagrangian optimization. However, the multivariate NR method and hence, the existing REM algorithm are applicable to vector parameters and the parameters of interest in this study are matrices. We, therefore, extended the NR approach to matrix parameters, which consequently allowed us to extend the REM algorithm to matrix parameters. The performance of the proposed estimators were examined using extensive simulations and a motivating real data example was provided to illustrate the application of the proposed estimators.

Finally, this thesis deals with high-dimensional application of GCM. Existing methods for a GCM are developed under the assumption of ‘small p large n’ (n >> p) and are not appropriate for analyzing high-dimensional longitudinal data, due to singularity of the sample covariance matrix. In a previous work, we used Moore-Penrose generalized inverse to overcome this challenge. However, the method has some limitations around near singularity, when p~n. In this thesis, a Bayesian framework was used to derive a test for testing the linear hypothesis on the mean parameter of the GCM, which is applicable in high-dimensional situations. Extensive simulations are performed to investigate the performance of the test statistic and establish optimality characteristics. Results show that this test performs well, under different conditions, including the near singularity zone. Sensitivity of the test to mis-specification of the parameters of the prior distribution are also examined empirically. A numerical example is provided to illustrate the usefulness of the proposed method in practical situations.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Optical Waveguides and Integrated Triplexer Filter

contributor:
Huang, W. P.
Electrical and Computer Engineering

subject: optical waveguides, integrated, triplexer filter, design, finite-difference, dielectric slab, multi-mode interference

abstract:
 The modeling, design and simulation of optical waveguides and integrated optical triplexer filters are presented. The work includes two subjects. One is application of improved three-point fourth-order finite-difference method and the other is design of triplexer optical filter for fiber-to-the-home passive optical network.

 The improved three-point fourth-order finite-difference method utilizes special format of one dimensional Helmholtz Equation and adopts generalized Douglas scheme and boundary conditions matching at interface. The modal analysis of dielectric slab waveguides and metal slab waveguides that support Surface Plasmon Plaritons by using this improved fourth-order finite-difference method is compared by using traditional first-order central difference method. The application of using improved three-point fourth-order finite-difference method in modal analysis of optical fiber waveguide is also provided.

 The modeling, design and simulation of monolithically integrated triplexer optical filter based on silicon wire waveguide are presented in detail. The design of this device facilitates multi-mode interference device (MMI) and arrayed waveguide grating (AWG) device to function as coarse wavelength division multiplexing and dense wavelength division multiplexing respectively. The MMI is used to separate downstream signs for upstream signal and AWG is used to further separate two down-stream signals with different bandwidths required. This design is validated by simulation that shows excellent performance in terms of spectral response as well as insertion loss.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Signal Designs for Non-negative Channels

contributor:
Zhang, Jian-Kang
Electrical and Computer Engineering

abstract:
In this thesis, we would like to design signals for non-negative  channels in some wireless communication systems such as visible light communication (VLC) systems and massive multiple-input and multiple-output (MIMO) RF communication systems. In the first part of this thesis, we consider the design of the optimal precoding matrix for an indoor multiple-input and multiple-output visible light communication system with a zero-forcing (ZF) equalizer and a threshold detector. We assume that the channel state information (CSI) is available at both transmitters and receivers. For such a system with non-negative $q$-PAM modulation, we propose an optimal precoding matrix design for transmitted signals such that the average symbol error probability (SEP) (or the bit error rate (BER)) is minimized. On the one hand, in the low SNR regime, our theoretical analysis suggests that we need to turn off one of two transmitters, and let the other work individually. Meanwhile, the constellation size should be improved to maintain the transmission rate. On the other hand, in high SNR scenario, both transmitters should transmit concurrently.  The computer simulations show that in high SNR,  BER for our proposed design is better than that of currently available methods.

In the second part of this thesis, considering the non-negative constraint on the transmitted signal and the channel in VLC systems, we are interested in designing a two-dimensional non-negative constellation with a specific unique decomposition. Compared with repetition coding (RC), spatial multiplexing (SMP) and spatial modulation (SM), space-collaborative constellation (CC) has the lowest average normalized optical power and better error performance in practical application for VLC. As for the multi-user situation, by using a recently developed  concept called additively uniquely decomposable constellation group (AUDCG), a whole (sum) constellation can be uniquely decomposed into several sub constellations to serve multi users at the same time. However, not all the CC can be decomposed into AUDCG. Then, we introduce several new methods to design a 2-dimensional constellation based on the idea of CC and AUDCG, which can serve two users with different priority strategies. The simulation result shows that our constellation design has lower average symbol error probability than traditional SMP in all strategies.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Female Religious Practices, Agency, and Freedom in the Novel Jin ping mei

contributor:
Benn, James
Religious Studies

subject:
Jin ping mei
Ming dynasty
Chinese religions

abstract: In the patriarchal milieu of sixteenth-century China, women demonstrated agency in their families and communities through their religious practices. Male family members typically performed Confucian rites related to ancestor veneration; yet there were many opportunities for women to participate in practices associated with other religious traditions. In this study, I will elucidate the religious roles of women during the late Ming dynasty (1368—1644 CE). Using the cultural-historical method, I will demonstrate the ways in which women gained agency and freedom from social conventions through their religious practices. By comparing literary sources with historical documents, I will validate the use of my major literary source, Jin ping mei, to study the religious practices in sixteenth-century China. This study will provide scholars with a nuanced understanding of gender roles within upper-class families in early modern China. Women were not simply passive, submissive members of a Confucian society; rather, they often gained authority and autonomy within their families and communities.

abstract: Thesis

abstract: Master of Arts (MA)


title: Statistical Methods for Data Integration and Disease Classification

contributor:
Beyene, Joseph
Health Research Methodology

subject:
Data Integration
Disease Classification
Bayesian Approach
Conditional Logistic Regression
Copula
Biomarker
Principal Component
Gamma Distribution

abstract: Classifying individuals into binary disease categories can be challenging due to complex relationships across different exposures of interest. In this thesis, we investigate three different approaches for disease classification using multiple biomarkers.  First, we consider combining information from literature reviews and INTERHEART data set to identify the threshold of ApoB, ApoA1 and the ratio of these two biomarkers to classify individuals at risk of developing myocardial infarction. We develop a Bayesian estimation procedure for this purpose that utilizes the conditional probability distribution of these biomarkers. This method is flexible compared to standard logistic regression approach and allows us to identify a precise threshold of these biomarkers. Second, we consider the problem of disease classification using two dependent biomarkers. An independently identified threshold for this purpose usually leads to a conflicting classification for some individuals. We develop and describe a method of determining the joint threshold of two dependent biomarkers for a disease classification, based on the joint probability distribution function constructed through copulas. This method will allow researchers uniquely classify individuals at risk of developing the disease. Third, we consider the problem of classifying an outcome using a gene and miRNA expression data sets. Linear principal component analysis (PCA) is a widely used approach to reduce the dimension of such data sets and subsequently use it for classification, but many authors suggest using kernel PCA for this purpose. Using real and simulated data sets, we compare these two approaches and assess the performance of components towards genetic data integration for an outcome classification. We conclude that reducing dimensions using linear PCA followed by a logistic regression model for classification seems to be acceptable for this purpose. We also observe that integrating information from multiple data sets using either of these approaches leads to a better performance of an outcome classification.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Role of Pragmatism in Explaining Heterogeneity in Meta-Analyses of Randomized Trials: A Methodological Review

contributor:
Mbuagbaw, Lawrence
Health Research Methodology

subject:
Pragmatic Trials
Methodological Review
Systematic Review
Heterogeneity
Meta-Regression
PRECIS-2
RITES

abstract:
Introduction:
There has been increasing interest in evidence from pragmatic trials as healthcare providers and decision makers must determine if available evidence can be translated and used in real world practice.  As a result, a number of tools have been developed to help researchers design and appraise randomized controlled trials (RCTs) within the pragmatic-explanatory continuum.  It is unclear what role pragmatism plays in heterogeneity and if pragmatic and explanatory trials should be pooled in meta-analyses of systematic reviews.

Objectives:
Our primary objective was to explore the role of pragmatism (based on the Pragmatic-Explanatory Continuum Indicator Summary-2 [PRECIS-2] score) as a source of heterogeneity in Cochrane systematic reviews with at least substantial heterogeneity (I2≥ 50%).  Our secondary objective was to compare and contrast the application of the established PRECIS-2 tool to the newly developed Rating of Included Trials on the Efficacy-Effectiveness Spectrum (RITES) tool.

Methods:
We conducted a cross-sectional methodological review on systematic reviews of RCTs published in the Cochrane Library from January 1, 2014 to January 1, 2017.  Included systematic reviews had a minimum of 10 RCTs in the meta-analysis of the primary outcome and at least moderate heterogeneity (I2≥ 50%).  Of the eligible systematic reviews, a random selection of 10 were included for quantitative evaluation.  In each systematic review, RCTs were scored using the PRECIS-2 and RITES tools, in duplicate, to determine the amount of pragmatism.  Meta-regression modelling was performed to evaluate how much variability in heterogeneity (quantified by I2) was due to pragmatism.  Inter-rater reliability of both PRECIS-2 and RITES was measured using the intraclass correlation coefficient and Spearman’s correlation coefficient was used to determine the strength of the relation between PRECIS-2 and RITES.

Results:
Ten systematic reviews from nine Cochrane Review Groups were included in the quantitative analysis.  The reviews included an average of 13 RCTs (standard deviation=2.6) for a total of 132 RCTs of which 128 could be obtained.  When the PRECIS-2 summary score was entered as a covariate in random effects meta-regression models for each systematic review, there were minimal changes in heterogeneity. The changes in I2 ranged from 0.2% to 13.3%.

Conclusion:
Based on these findings it appears pragmatism as measured by PRECIS-2 does not explain heterogeneity in systematic reviews, therefore pooling of pragmatic and explanatory RCTs is unlikely to be detrimental to meta-analyses.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Systematic reviews and meta-analyses of randomized controlled trials (RCTs) are an important scientific activity that can lead to changes in health care.  However, there is concern whether it is appropriate to meta-analyze data from RCTs that are performed under more controlled conditions (explanatory RCTs) and RCTs that are performed under more real world conditions (pragmatic RCTs) since there may be variability between them.  The purpose of this research was to explore how much these trial types affect variability, otherwise known as heterogeneity, in systematic reviews.  We applied a scoring tool called the Pragmatic-Explanatory Continuum Indicator Summary-2 (PRECIS-2) to RCTs within 10 systematic reviews with at least moderate heterogeneity and performed statistical modelling to determine how much heterogeneity could be explained by a trial being more or less pragmatic.  Results showed that trial type did not explain heterogeneity therefore it is probably reasonable to meta-analyze data from pragmatic and explanatory RCTs.


title: SREBP-1 and Cell Surface GRP78 are important modulators of TGF-β1 in the progression of diabetic nephropathy

contributor: Medical Sciences (Blood and Cardiovascular)

subject: diabetes kidney fibrosis grp78 srebp tgf-beta

abstract:
Diabetic nephropathy represents the leading cause of end stage renal disease worldwide and requires a kidney transplant or dialysis to survive. The number of patients suffering from diabetes is expected to increase, thus the number of patients with diabetic nephropathy is expected to concomitantly increase. Current treatment for diabetic nephropathy is not sufficient to prevent disease progression in most patients thus there is a need to develop novel therapies to treat diabetic nephropathy.
The earliest changes that occur during the pathogenesis of diabetes occur in the glomerulus. The mesangial cells are a subpopulation of cells in the glomerulus that are responsible for coordinating responses with other nearby cell types. Transforming growth factor (TGF)-β1 is a cytokine that mesangial cells secrete, and has been identified as a profibrotic factor during the pathogenesis of diabetic nephropathy. Concerns have been raised in the use of direct anti-TGF-β1 therapy due to adverse events (such as dyspepsia and diarrhea) and lack of efficacy of anti-TGF-β1 monoclonal antibody LY2382770 in patients with diabetic nephropathy. Thus, therapy aimed at modulating TGF-β1 expression or activity may be efficacious in the treatment of diabetic nephropathy while avoiding potential adverse effects.
The hypothesis of this thesis is that SREBP-1 and cell surface GRP78 are novel regulators of TGF-β1 signaling in mesangial cells. Our first study aims to define a novel pathway by which SREBP-1 regulates TGF-β1 signaling in kidney mesangial cells. Our results indicate that SREBP-1 regulates the expression of the type I TGF-β1 receptor through its secretion in exosomes. Our second study expands on these findings and aims to determine if inhibition of SREBP in vivo with the inhibitor fatostatin may prevent diabetic nephropathy. Our results indicate that treatment with fatostatin does not prevent diabetic nephropathy, but accentuates kidney injury in non-diabetic mice. Preliminary results from our lab have indicated that under diabetic conditions, GRP78 is upregulated at the cell surface and may contribute to the activation of SREBP-1 in an ER-stress dependent mechanism. Our third study thus aims to characterize the expression of cell surface GRP78 in diabetic conditions, and to determine its pathological relevance in the development of diabetic nephropathy. Our results have established novel pathways by which TGF-β1 signaling is regulated in mesangial cells. This will assist in identification of novel therapeutic targets that may be of use in the treatment of diabetic nephropathy.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Diabetic kidney disease is the leading cause of end stage renal disease and represents an important risk factor for mortality. The goal of this thesis is to understand and describe the pathways and mechanisms that contribute to the development of diabetic kidney disease in order to identify novel therapeutic targets. This thesis has identified the protein sterol regulatory element binding protein (SREBP)-1 and the cell surface presentation of another protein, the 78 kDa glucose regulated protein (GRP78), as contributors to diabetic kidney disease.  Furthermore, this thesis has demonstrated that anti-SREBP therapy with the drug fatostatin did not prevent diabetic kidney disease. These studies show that while inhibiting SREBP-1 and cell surface GRP78 may be effective in the treatment of diabetic kidney disease,  the drug fatostatin should not be used for treatment.


title: Offset-Based Beamforming: A New Approach to Robust Downlink Transmission

contributor:
Davidson, Timothy
Electrical Engineering

abstract:
This thesis describes the design of low-complexity robust linear beamforming algorithms for multi-user downlink multiple-input single-output (MISO) communication systems. The goal of the algorithms is to provide the receivers with specified signal-to-interference-and-noise ratios (SINRs) with high probability under certain power constraints. Unfortunately, the SINR outage constraint is intractable, and precise formulations of these problems are fundamentally hard to solve. The contribution of this thesis is a suite of algorithms that provide high-quality approximate solutions to a broad range of robust downlink beamforming problems, and do so at low computational cost. The unifying feature of these algorithms is that they are based, either explicitly or implicitly, on a transformation of each SINR outage constraint into a non-negativity constraint on a random variable, and the approximation of that non-negativity constraint by offsets on the mean of the distribution.
The  first algorithm is developed for frequency division duplexing systems. Using a new extension of the S-Lemma, the channel uncertainty model is incorporated into the design problem using a zero-outage region approach. From that formulation, a new algorithm that is able to balance between the performance inside and outside the zero-outage region is developed. The resulting offset maximization algorithm has a low-complexity iterative closed-form solution that provides significant  performance improvement, and can be extended to time division duplexing systems.
Analysis of the offset structure reveals a refined notion of the offset that incorporates information about each user's channel, and results in a convex semidefinite relaxation problem. When the channel uncertainty size is small, further approximations lead to an approximate iterative closed-form solution. When the beamforming directions are defined in advance, that algorithm provides near-optimal power loading. Using subgradient methods, variants of the  offset maximization algorithms that can accommodate per-antenna power constraints (PAPCs) are developed. Furthermore,
the resulting offset-based power loading method can be combined with the maximum ratio transmission (MRT) or zero-forcing (ZF) directions, to provide robust algorithms that satisfy PAPCs with complexities low enough for massive MIMO applications.
Finally, the principles of the offset maximization algorithm are applied to multi-cell systems with the centralized cooperation, and with the centralized and decentralized architectures. The resulting algorithms provide significant performance improvement over those existing in the literature, and do so at substantially lower computational
cost.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The increasing number of smart devices and Internet-based applications are driving the demand for higher data-rate wireless communication systems. One way to address that demand is to use multiple antennas at the base station to enable it to simultaneously serve multiple users instead of one. When such a base station is provided with the channel to each user, it can focus the energy of each data symbol towards the intended user while reducing the interference imposed on the other users. This is called beamforming. However, in practice the channel to each user is estimated and the beamformer design ought to include techniques that mitigate the impact of the resulting uncertainty. The goal of this thesis is to develop a suite of robust beamformer design techniques that do so, while also being of low-complexity, able to handle different power constraints, and being extendable to multi-cell systems in which multiple base stations may cooperate or coordinate in transmitting data to the users.


title: THE SOPHIST IN PLATO’S STATESMAN: AN ARGUMENT FOR THE TYRANT AS THE FALSE IMITATOR OF THE STATESMAN

title: THE SOPHIST IN PLATO’S STATESMAN

contributor:
Johnstone, Mark
Philosophy

subject: plato, statesman, sophist, tyrant, political philosophy

abstract:
The use of the term “sophist” in Plato’s Statesman has been understood to apply to all rulers who are not statesmen. They do not have the statesman’s expert knowledge but they all imitate the statesman. This seems to be consistent with the idea that a sophist is a false imitator.
I argue against this interpretation and instead insist that only the tyrant in the Statesman is a sophist. I base this argument on the final definition of the sophist in Plato’s Sophist and the discussion of imitation in the Sophist. The tyrant is an important figure in the Statesman, even though he is only mentioned briefly. He is the ruler who pretends to be a statesman so that he can rule with the statesman’s power which is above the law.
I use my narrower interpretation of the term “sophist” in the Statesman to argue that Plato’s purpose in the discussion of laws and regimes in the Statesman is to protect the city from the tyrant as a sophist. This requires that the people of the city recognize their own ignorance and completely forbid any type of political leadership that would make the city vulnerable to the false statesman. Instead, they imitate the statesman by their complete obedience to the law.
The idea of complete obedience to the law, without any room for modification or change, is not politically appealing. However, it is important that part of Plato’s solution to the problem of tyranny is self-awareness of our lack of political knowledge.

abstract: Thesis

abstract: Master of Arts (MA)

abstract:
The use of the term “sophist” in Plato’s Statesman has been understood to apply to all rulers who are not statesmen. Instead, I argue that only the tyrant in the Statesman is a sophist. I base this argument on the final definition of the sophist in Plato’s Sophist and the discussion of imitation in the Sophist.
I use my narrower interpretation of the term “sophist” in the Statesman to argue that Plato’s purpose in the discussion of laws and regimes in the Statesman is to protect the city from the tyrant as a sophist. This requires that the people of the city recognize their own ignorance and completely forbid any type of political leadership that would make the city vulnerable to a false statesman.
This argument is important as it shows that part of Plato’s solution to the problem of tyranny is self-awareness of our lack of political knowledge.


title: Pictures, Pantomimes, and a Thousand Words: The Neuroscience of Cross-Modal Narrative Communication in Humans

contributor:
Brown, Steven
Psychology

subject:
drawing
visual motion
cross-modal communication
fMRI
DTI
tractography

abstract: Communication is the exchange of thoughts and ideas from one person to another, often through the form of narratives. People communicate using speech, gesture, and drawing, or some multimodal combination of the three. Although there has been much research on how we understand and produce speech and pantomimes, there is relatively little on drawing, and even less on cross-modal communication. This dissertation presents novel empirical findings that contribute to a better understanding of the brain areas that mediate narrative communication across speech, pantomime, and drawing. Since the neuroscience of drawing was so understudied, I first used functional magnetic resonance imaging (fMRI) to investigate the existence of a basic drawing network in the human brain (Chapter 2). The drawing network was shown to contain three visual-motion areas that process the emanation of the visual image as drawing occurs. Next, to follow up on the poorly-characterized structural connectivity of these areas in the human dorsal visual stream, I used diffusion imaging to explore how these dorsal stream areas are connected (Chapter 3). The tractography results showed structural connectivity for two of the three predicted branches connecting the three visual-motion areas. Finally, I used fMRI to investigate how the basic drawing network is recruited during the more complex task of narrative drawing, and to find common brain areas among narrative speech, pantomime, and drawing (Chapter 4). Results suggest that people approached narratives in an intrinsically mentalistic fashion in terms of the protagonist, rather than as a mere description of action sequences. Together, these studies advance our understanding of the brain areas that comprise a basic drawing network, how these brain areas are interconnected, and how we communicate stories across three modalities of production. I conclude with a general discussion of my findings (Chapter 5).

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Koke_Hannah_R_2017September_MASc

title: Comparative Study of Stranded and Bar Windings in an Induction Motor for Automotive Propulsion Applications

contributor:
Emadi, Ali
Mechanical Engineering

subject:
Induction Motors
Electric Machines
Optimization
Efficiency maps

abstract: The source-to-wheel efficiency of today's electrified vehicles already far surpasses the efficiency of strictly gasoline vehicles. As sources of electricity become cleaner and more efficient, and as gasoline becomes more scarce, the need for transporation electrification is increasingly economically and environmentally driven. The automotive industry primarily makes use of permanent magnet synchronous machines (PMSMs) and induction machines (IMs), the latter has the cost advantage of containing no rare earth metals. This thesis studies two different induction motors for electrified powertrain applications using a novel optimization algorithm to create efficiency maps and compare the efficiencies of the two motors. Induction motors are difficult to banchmark due to their complicated control schemes. Each point in their operating range can be achieved with an infinite number of current/slip combinations and therefore has infinite potential efficiencies. The proposed algorithm limits the number of simulations needed to benchmark an induction machine, and provides a clear and unbiased way to compare machines based on losses at their most efficient current/slip combinations over their entire operating range. The proposed algorithm is able to calculate losses within 5% error of simulation values for both machines. The first motor studied makes use of stranded windings and geometry parameters from the Tesla Motors patents. The efficiency map created has a peak efficiency of 96% and corresponds closely to an efficiency map for a similar motor found in literature. The second motor makes use of copper bar windings, which are easier to manufacture and have lower material costs. Bar windings, typically have lower resistance and stator copper losses at low speeds, but higher effective resistance and stator losses at high speeds due to eddy effects. The motor modelled was intended simply to compare the stranded and bar windings, and to see the advantages and disadvantages. For this reason, no other changes are made to the winding layout or motor geometry, including changes that would reduce the eddy effect. The resultant efficiency map has a peak efficiency of only 90%, performing worse than the stranded wound motor across most of its operating range. At very low speeds, under 1000 rpm, the efficiency of the bar wound machine is better than that of the stranded machine. The bar wound machine also has the advantage of being over 80\% efficient everywhere. The author suggests that future research focus on applying the proposed benchmarking algorithm to stator bar motors designed to limit eddy effects. Strategies include changing the slot opening shape, increasing the number of stator bars, and moving the stator bars away from the air gap.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Understanding the role of Type I Interferon in regulating the Innate Immune Response during Herpes Simplex Virus Type 2 Infection

title: Type I IFN regulates Innate Immunity during HSV-2 Infection

contributor:
Ashkar, Ali
Medical Sciences

subject: Mucosal immune response, Virus infection, Natural killer cells, Type I interferons

abstract: Type I interferons (IFN) are a potent antiviral cytokine group that are key regulators of the immune response against virus infection. Not only does this group activate antiviral states within target cells, it can modulate the innate immune response. In the studies presented, we investigate the effects of type I IFN on the innate immune system during a mucosal vaginal virus infection, herpes simplex virus type 2 (HSV-2), a prominent sexually transmitted infection that causes genital herpes and increases risk of human immunodeficiency virus acquisition. It is well known that type I IFN is critical for natural killer (NK) cell activation. These cells contribute to the antiviral response by suppressing virus replication and aiding in the initiation of the adaptive immune response, particularly through the release of IFN-γ. In the work presented, we demonstrate that type I IFN does not act on NK cells directly for their activation, but instead activates NK cell IFN-γ production by inducing inflammatory monocytes to release IL-18, which in turn, signals NK cells to release IFN-γ during a mucosal HSV-2 infection. Rather, direct action of type I IFN on NK cells serves to negatively regulate their IFN-γ response. We also found that type I IFN was critical for suppressing virus-induced innate immunopathology during HSV-2 infection. Overall, our studies further our understanding of type I IFN and the many roles it plays during virus infection, which has become more relevant as specific therapies altering type I IFN are being used in the clinic. Further, we provide a fundamental understanding of type I IFN and its ability to shape the innate immune response to virus infection by suppressing dysregulated and immunopathological functions while promoting beneficial innate immune responses that can help fight the infection.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Type I interferons (IFN) are a group of proteins that are rapidly produced early during infection and is important for combatting virus infections. We show that type I IFN is not just an antiviral molecule, but can modulate the initial immune response to virus infection. As part of the initial immune response, Natural killer (NK) cells are immune cells that respond rapidly to infection and are a key element in controlling the early stages of infection. We found that type I IFN is critical for activating NK cell function by signaling through an intermediary cell, but can also suppress that same function by directly acting on NK cells. We also found that type I IFN is critical for suppressing a dysregulated immune response that causes severe virus-induced vaginal pathology. Overall, our data suggests that type I IFN is a key antiviral molecule that shapes the immune response to virus infection.


title: ELECTROLYSIS-BASED SYSTEM FOR GENERATION AND DELIVERY OF OXYGEN TO MICROFLUIDIC OXYGENATOR UNIT FOR PRETERM NEONATES WITH RESPIRATORY DISTRESS SYNDROME

contributor:
Selvaganapathy, P. Ravi
Biomedical Engineering

subject:
artificial placenta
oxygenator
respiratory distress syndrome
electrolysis
oxygen generation
preterm neonates
microfluidics

abstract: Design and development

abstract:
Respiratory distress syndrome (RDS) is a major cause of mortality and long-term morbidity annually affecting 14% preterm infants worldwide. Therapies have been developed to overcome this common disorder; however, limitations exist with these treatments that often lead to complications including bronchopulmonary dysplasia (BPD). One approach to address RDS is to implement a microfluidic oxygenator that serves as a respiratory support system for preterm neonates while the lungs fully develop, extra-uterine. This artificial lung assist device (LAD) is characterised by its non-invasiveness (given that it is connected via umbilical vessels), pumpless configuration, ambient air operation, portability and low priming volume. Furthermore, the LAD is formed by single oxygenator units (SOU) that are stacked in a parallel array which allows for usage on different body weights.
The objective of this thesis is to design an electrochemical system to provide an in-situ enriched O2 environment able to supply 1.9 ml O2/min for use in the SOU while maintaining the simplicity of operation of the oxygenator. An inexpensive, electrically powered and compact device was envisioned allowing for a higher permeation flux to fully oxygenate the blood. Moreover, the system would be easy to manufacture, low maintenance and avoid the risk of gas contamination.
In the initial work, different designs of electrolytic cells were developed and tested. The two- chamber design connected by a gel membrane showed an O2 production 10 times higher than with previous designs with 42 mg O2/L. Subsequently, different supporting electrolytes were tested. NaOH demonstrated a better performance and no degradation of the electrode in contrast to NaCl and Na2SO4. Stainless steel mesh (SSM) and graphite sheet electrodes were then tested; it was observed that stainless steel produced 3.4 times more dissolved oxygen (DO) than graphite with 28.3 mg O2/L. Experimentation with electrolysis of water showed that the DO in water reached stability 3 min after the electrolysis process was initiated measuring a change of DO of 29 mg/L at 3 A. Furthermore, an active oxygenation (AO) system was developed for in-vitro experiments via electrolysis of water and compared to a passive oxygenation (PO) system exposing blood to enriched O2 air and ambient air, respectively. It was demonstrated that AO provided 300% greater oxygenation to blood than PO.
The electrolysis chamber designed for the microfluidic oxygenator allows the oxygenator to maintain its essential characteristics of simplicity and low cost while increasing the rate of oxygenation of blood. Preterm neonates suffering from RDS need an artificial lung that can partially support the oxygenation of their blood. Thus, combining the oxygenator with the O2 generation in-situ system enables a greater blood O2 uptake of 300% making possible the development of an efficient artificial lung.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Snakes and Labyrinths: Adhesion-Induced Fingering Instabilities in Thin Elastic Films

contributor:
Dalnoki-Veress, Kari
Physics and Astronomy

subject:
physics
soft condensed matter
pattern formation
instabilities
thin polymer films
adhesion

abstract: Fingering instabilities can be observed when studying many different phenomena and display elegant pattern formation. Adhesion-induced fingering instabilities, discovered in the early 2000s, are instability patterns that arise when elastic films are sandwiched between two rigid surfaces. In this thesis we investigate this adhesion-induced fingering instability in thin elastic films. This work builds upon previous research into this instability. Experiments based on studies in the literature were performed to further examine past results; general scaling rules were confirmed, but discrepancies between current and past data show that there is still much to understand theoretically. We also perform novel experiments to elucidate the effects of strain on the instability pattern. It is found that the pattern aligns with the direction of strain in a thin film. We provide a theoretical model to explain this result.

abstract: Thesis

abstract: Master of Science (MSc)


title: Ending Intimate Partner Violence: Preventative versus Restorative Interventions - Are We Waiting Too Long?

contributor:
Carranza, Mirna
Social Work

subject:
Intimate Partner Violence
Intervention

abstract: This qualitative study aimed to explore the connection between experiences of childhood family violence and the perpetration of intimate partner violence. Rooted in an interpretivist methodology, the perceptions and experiences of six male participants were explored via individual interviews. The participants identified having experienced/witnessed family violence. They too stated perpetuating intimate partner violence. The participants were asked questions exploring how they perceived their childhood experiences and/or exposure to family violence to have and continue to impact them into adulthood. Based on the stories of these participants, four major themes were identified; however, ultimately, the importance of adequate and appropriate responses to the external manifestations of the impacts of family violence was emphasized. The discussion urges that current restorative responses to intimate partner violence be evaluated for ones that are preventative in nature, as well as suggested based on the specific needs of each individual.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: INTERFACIAL INTERACTIONS OF OLIGOANILINES WITH SOLID SURFACES

contributor:
Kruse, Peter
Chemistry

subject:
Oligoanilines
Chemical Sensors
Interfacial Charge Transfer
Surface Doping
Small Molecules
Corrosion Inhibition
Iron Oxide
Graphite
Pencil Lead

abstract:
It is known that organic monolayers on solid surfaces can enable electronic properties that are absent in the bulk of the solid materials. Often, once the organic film come into the contact with a solid surface, the established electronic interaction at their interface remains undisturbed. However, using a redox-active organic monolayer creates the possibility for modulating the extent and the direction of the interfacial charge transfer, establishing a switch at the interface.
The theme of this thesis is investigation of the interfacial interaction of different redox states of a molecular switch, phenyl-capped aniline tetramer (PCAT) with iron oxide and graphite surfaces and their potential application in electronic devices. The nucleation and growth of submonolayer films of different oxidation states of PCAT on iron oxide surface was studied. Using atomic force microscopy and scaling island size distribution method the surface diffusion parameters of these islands were evaluated. Using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy the changes in these organic monolayers before and after interaction with iron oxide were demonstrated. However, these techniques were unable to provide similar data from the solid surface side of the interface. Instead, we were able to demonstrate the changes in the iron oxide film as a result of interfacial charge transfer using electrical conductivity measurement techniques. Based on this information a microfluidic chemical sensor based on the interface of pencil film and PCAT for quantification of free chlorine in drinking water was constructed. Using XPS and UV-vis spectroscopy it was shown that the interaction the organic monolayer with sodium hypochlorite solution leads to the development of positive charges on the backbone of PCAT. This electrostatic charge can affect the charge transport in the pencil film causing the modulation of electrical conductivity of the film. The presented work demonstrates alternative pathways for the design of novel hybrid electronic devices based on thin molecular film and solid surfaces.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Patterns of parental care and chick recognition in a joint-nesting rail, Pūkeko (Porphyrio melanotus melanotus)

contributor:
Quinn, James S
Biology

subject:
cooperative breeding
joint nesting
pukeko
bird behaviour
animal behaviour
kin recognition

abstract: Group living is a widespread social system among animals. Within these groups, decisions on interactions between individuals can be facilitated through knowledge about individual identity and kinship. Individual identity allows for the recognition of individuals from past interactions and thus, information on likelihood of reciprocity and group-membership can be gained. The benefit for cooperative interactions, specifically, increases with the level of relatedness between the helper and the recipient. Thus, knowing who is kin, is an essential ability among group-living species and remembering individual identity helps to maintain long-term relationships and inform future decisions. Kin recognition can be facilitated through temporal and spatial overlap (i.e. familiarity) or through phenotypic-templates (i.e. phenotype matching). The goal of this thesis was to explore recognition in the joint-nesting pūkeko (Porphyrio melanotus melanotus). For the first portion of this thesis (Chapter II), I tested for evidence of phenotype matching in pūkeko using a cross-fostering experiment. Comparing survival and growth between fostered and non-fostered offspring, I provide evidence that pūkeko do not use phenotype matching as their mechanism for kin recognition. In Chapter III, I show that pūkeko chick distress calls may have an individual and group signature. I found variation in the vocal parameters between individual chicks and social groups. I also tested for response of adults towards chick distress calls of their own group. Using a playback-choice experiment, I report a biased response of adult pūkeko towards the distress call of their own group's chicks rather than the call of a distressed chick from a foreign chick.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Kin recognition is an essential ability for social species. Knowing whom is kin can help inform decisions on cooperation and conflict. I explored whether the joint-nesting pūkeko use familiarity or phenotype matching to recognise cross-fostered offspring. I experimented to determine if adult pūkeko can recognise the distress vocalizations of chicks in their group. I found no evidence that pūkeko use phenotypic templates to recognise cross-fostered chicks as non-kin. However, adult pūkeko showed a bias in response towards the distress calls of their own versus unfamiliar chicks. Individual chick distress calls, while variable from day-to-day, show group-specific similarities.


title: COGNITIVE AUDIOLOGY: INVESTIGATING THE EFFECTS OF COGNITIVE LOAD AND INDIVIDUAL DIFFERENCES IN COGNITIVE CAPACITY ON HEARING

contributor:
Watter, Scott
Psychology

subject:
audition
working memory
working memory capacity
dual-task
listening effort
divided attention
cognitive load

abstract: Listening ability is affected by external factors such as background noise and internal factors such as attention-allocation. I varied listening conditions and cognitive load and evaluated auditory word recognition and ratings of listening effort. Additionally, I investigated how individual differences in working memory capacity affected word recognition, recall, listening effort, and how working memory capacity interacted with other factors. Rönnberg et al.’s (2013) Ease of Language Understanding (ELU) model states that individual differences in working memory capacity will lead to differences in language comprehension in challenging listening conditions, where those with higher working memory capacity will be better at speech recognition. Using a dual-task experiment, participants heard and repeated words presented in three listening conditions: masked with pink noise, masked with babble, and processed through a hearing loss simulator. To manipulate cognitive load, participants completed the speech recognition task in both single- and dual-task paradigms. In the dual-task paradigm, participants continuously tracked a pseudo-randomly moving target on a screen for half the experiment. Participants reported perceived listening effort for each combination of listening condition and tracking condition. Additionally, memory for correctly heard words was tested with a recognition memory test. Word recognition performance and listening effort rating data agreed with my hypotheses that difficult listening conditions would produce poorer word recognition performance and increased listening effort. Interesting effects of cognitive load are discussed. The relation between working memory capacity and performance on various measures is also discussed in the context of the ELU model and theories of working memory capacity. Internal and external factors clearly interact to affect listening, and this interaction varies across individuals.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The ability to hear is affected by many factors, including attention and memory. The goal of this research is to investigate the cognitive factors (attention and memory) that affect hearing and how these effects differ on an individual level. My findings contribute to a better understanding of how background noise and mental demand affect hearing ability and listening effort, as well as how individual differences in cognitive ability further influence these factors. Results suggest that background noise and increased mental demand will decrease listening ability and increase listening effort. These changes in listening differ according to individual cognitive ability.


title: Neural Correlates of Premenstrual Dysphoric Disorder in Women with Bipolar Disorder

contributor:
Minuzzi, Luciano
Frey, Benicio Noronha
Neuroscience

subject:
Bipolar Disorder
Premenstrual Dysphoric Disorder
Menstrual Cycle
fMRI
Hormones
MRI

abstract:
Introduction: Women with bipolar disorder (BD) have higher rates of premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD). The primary goal of this thesis was to examine the neural correlates of bipolar disorder and comorbid PMDD and identify changes in brain structure or function that may mediate emotional and cognitive dysregulation in the late luteal phase.
Results: In healthy women with no history of PMDD, absolute levels of estradiol, progesterone, allopregnanolone and dehydroepiandrosterone sulfate (DHEAS) were correlated with patterns of functional coupling in multiple regions associated with emotional and cognitive processes, in the mid-follicular and late luteal menstrual phases. A systematic review of the literature on resting state functional connectivity (Rs-FC) in BD during euthymia highlighted consistent patterns of resting state functional connectivity (Rs-FC) using ICA and SBA; including stability of the default mode network (DMN), salience network (SN) and fronto-parietal network (FPN) relative to controls. Available literature largely failed to control for sex, menstrual cycle phase or menstrual cycle disorders. Thus, we conducted the first fMRI studies to control for menstrual cycle phase in BD. During the mid-follicular phase, we found increased Rs-FC between critical nodes of the default mode and frontoparietal networks in BD compared to controls and increased functional connectivity between the somatosensory cortex and the insular cortex, inferior prefrontal gyrus and frontal orbital cortex in BD compared to controls. Voxel based morphometry analysis showed decreased gray matter in the somatosensory cortex in the same population compared to controls. Finally, women with BD and co-morbid PMDD displayed different patterns of Rs-FC using the right and left hippocampi as seed regions than women with BD without comorbid PMDD and controls with PMDD. Differences in cortical thickness between controls with and without PMDD and with and without BD were also found in regions central to emotional regulation and cognitive processing.
Conclusions: Results highlight the influence of sex hormones on Rs-FC and support the need to control for menstrual phase and PMDD diagnosis. Differences in structural and functional connectivity, and the clinical profile of women with BD and those with BD and co-morbid PMDD highlights the impact of PMDD on BD and the need for future research in this area.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Cross disorder homogeneity: An examination of neurodevelopmental disorders through behavioural correlates and functional connectivity

contributor:
Hall, Geoffrey
Psychology

abstract:
Over 300,000 children in Ontario are diagnosed with neurodevelopmental
disorders, which are defined as mental disorders with an onset in the developmental
period. Autism spectrum disorder (ASD), attention-deficit hyperactivity disorder
(ADHD), and obsessive-compulsive disorder (OCD) are three neurodevelopmental
disorders with symptom overlap including difficulties with social skills, inattention, and
behavioural flexibility. The National Institute of Mental Health (NIMH) proposed the
Research Domain Criteria (RDoC) to address these overlaps by examining symptoms at a
biological, as well as observable, level. This study investigated how children with
diagnoses of ASD (n=90), ADHD (n=47), and OCD (n=32) group together based on their
symptom scores on the Social Communication Questionnaire (SCQ), the inattention
subscales of the Child Behaviour Checklist (CBCL), and the behaviour flexibility
subscales of the Repetitive-Behaviour Scale-Revised (RBS-R). Correlations between
cluster groupings and functional connectivity were then evaluated. Children were
clustered into 3 groups: (1) a group characterized by high inattention; (2) a group
characterized by moderate impairment across social skills, inattention, and behavioural
flexibility; and (3) a group characterized by high impairment in all measures. Functional
connectivity between the anterior cingulate cortex and intraparietal sulcus was positively
correlated with symptom scores on behavioural flexibility in group 1. Connectivity
between the right amygdala and both the left superior temporal gyrus and the lateral
parietal region were negatively correlated with symptom scores on behavioural flexibility
in group 3. This study was the first to collapse across diagnostic groups of neurodevelopmental disorders, and examine the correlation between symptom severity
and functional connectivity. Findings support the use of the RDoC framework.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
The current study investigated the behaviour and brain functioning of children
with neurodevelopmental disorders. We examined how children with autism spectrum
disorder (ASD; n=90), attention-deficit hyperactivity disorder (ADHD; n=47) and
obsessive-compulsive disorder (OCD; n=32) group together based on their difficulties
with social skills, inattention, and behavioural flexibility. We then associated their
symptoms to brain functioning at rest. We found that groupings based on difficulties and
symptoms did not correspond with diagnosis, and that rigidity was associated with brain
activity in the attention networks and social networks of the brain for different groups.
This study supports the use of biological systems, rather than solely observable
behaviour, to further our understanding of neurodevelopmental disorders.