title: Structure-Property-Process Studies During Axial Feed Hot Forming and Fracture of Extruded Polypropylene Tubes

contributor:
Jain, M. K.
Mechanical Engineering

subject:
axial feed hot oil tube forming process
oriented thermoplastic tubes
oriented polypropylene tube
solid state extrusion
tube formability
flow localization
fracture characteristics

abstract:
Oriented thermoplastics offer interesting opportunities for making structural automotive components due to their higher strengths. A new process, referred to as the axial feed hot oil tube forming (AF-HOTF) process, has been developed and studied for the forming of oriented thermoplastic tubes. The starting material for AF-HOTF process is an oriented polypropylene (OPP) tube produced by the solid state extrusion process. AF-HOTF was used to study forming and fracture behaviour of OPP tubes at large strains. Mechanical properties and molecular orientation of starting and post-formed materials were investigated to gain a better understanding of structure-property-process relationships during solid state extrusion and subsequent forming of OPP tubes. The
development of molecular orientation and other microstructural changes and damage development in extruded and bulged OPP tubes during solid state extrusion and AF-HOTF processes were studied with optical microscopy, wide-angle X-ray diffraction (WAXD) and field emission scanning electron microscope (FE-SEM) techniques. Also, the development of large strains during AF-HOTF of OPP samples were experimentally studied in the form of spatial strain maps, strain/stress state and forming limit strains using an on-line strain mapping method based on digital image correlation (DIC). In addition, tensile tests have been carried out at room temperature on samples machined from the extruded and bulged tubes along the axial and hoop directions. Experimental quantitative relationships amongst molecular orientation parameters and extrusion and AF-HOTF process parameters such as draw ratio, strain and strain state have been obtained. These relationships in the form of White and Spruiell biaxial orientation factors provide a useful insight into molecular reorientation that occurs during extrusion and subsequent forming of OPP tubes. Also, an analytical model for forming
limit prediction that takes into account OPP tube properties, tube dimensions and AF-HOTF process parameters was developed based on existing model of tube hydroforming in the literature. In addition, a new biaxial ball stretching test (BBST) system was developed and utilized to subject the thermoplastic tube to biaxial stretching. The design of the test-rig and results were presented for polypropylene (PP) tubes subjected to BBST at various temperatures. The BBST system was combined with an available on-line imaging and strain analysis system (ARAMIS® system from GOM) to observe the development of strains in the biaxial tensile region during the test. BBST samples were studied with wide angle X-ray diffraction (WAXD) pole figures. Three different hot forming processes (Solid-state extrusion, AF-HOTF and BBST) were used in this research. The structure of the extruded samples at draw ratio 5 and higher was completely changed to fibrils structure, and the yield strength and elastic modulus increased by 50%. Also the crystallinity increased from 47% to 68% with an increase in draw ratio. An increase in axial feed during the hot forming process resulted in higher formability (strains values of 0.55 major strain and -0.25 minor strain) and delayed failure. The analytical model prediction of bursting shows good agreement with the experimental results. The results provide an understanding of the orientation development in solid state extrusion of PP tubes as well as an understanding of tube formability, flow localization and fracture  characteristics of PP tube from AF-HOTF process and other related
processes.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Three Essays on Education in Egypt

contributor:
Magee, Lonnie
Economics

subject: private tutoring in Egypt

subject: gender bias

subject: socioeconomic level

subject: marriage prospects for an educated women

abstract:
Private tutoring is prevalent in Egypt and other developing countries. Nonetheless, the
literature on tutoring is still small. The purpose of the first paper in this thesis is to gain an
understanding of the determinants of tutoring in Egypt using micro-level data and to investigate whether gender bias exists in tutoring decisions. It is expected that since labor market outcomes are less favorable to girls and gender disparities are present in educational investments in general, parents would be less willing to invest in tutoring for girls. Surprisingly, however, no gender bias is detected with respect to tutoring. The absence of bias is a puzzling finding. Tutoring is used to enhance children's education performance and give them a competitive edge. Socioeconomic level was found to be an important predictor of tutoring investment in the first paper. This poses equity concerns. Therefore, it is important to examine whether tutoring pays off in terms of better educational outcomes. The literature on tutoring effects mostly does not take into account the potential endogeneity of tutoring. I estimate the effect of taking tutoring on the likelihood of joining the secondary level stream that leads to university in the second paper of the thesis. I use a proxy for the supply of tutors as an instrument for taking tutoring. Without instrumenting, tutoring has a statistically significant positive effect. After introducing the instrumental variable, this effect disappears. However, the estimate of the tutoring coefficient is imprecise and there is some evidence that the instrument variable does not have sufficient power to get a reliable estimate of the tutoring effect. The expectation of better marriage prospects for an educated woman may influence parental educational investment decisions and this can be the answer to the puzzle of apparently equal tutoring investment by gender as found in the first paper of the thesis. The third paper examines how female education improves marriage characteristics in Egypt. Findings show that highly educated women are more likely to marry a highly educated husband. They are also more likely to man-y a husband with a high pre-marital wealth level and to live independently upon marriage. Higher levels of female education are negatively associated with marrying a relative. Female education plays an insignificant role with respect to the share of marriage costs borne by a bride and her family.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Role of p53 and Hypoxia in Nucleotide Excision Repair

contributor:
Rainbow, A. J.
Biology

subject:
nucleotide excision repair
global genome repair
transcription-coupled repair
HIF-1α
primary human fibroblast
UVC radiation sensitivity
p53 regulation
acidosis
rat prostate tumour cells

abstract:
The nucleotide excision repair (NER) pathway is essential for repair of UV-induced bulky DNA lesions. NER is divided into two subpathways: global genome repair (GGR) and transcription-coupled repair (TCR). UVC radiation has been shown to result
in the formation of bulky DNA lesions, which are removed by NER. Previous published reports have shown a role for the p53 tumour suppressor protein in GGR and TCR, but the involvement of p53 in TCR has been controversial. In addition, it has also been suggested that hypoxia affects NER and expression of p53. In the present work, the role of p53, hypoxia and HIF-lα in NER was investigated. It was determined that p53 overexpression in primary human fibroblasts resulted in up-regulation of both the GGR and TCR subpathways of a UV -damaged reporter gene. Pre-treatment of cells with low UVC-fluence and p53 overexpression also induced an upregulation of GGR and TCR. These results are consistent with a p53-dependent upregulation
of TCR and GGR of the UVC-damaged reporter gene, as well with a UV-inducible TCR and GGR that is dependent on p53 expression prior to UV treatment. Hypoxia coupled to low pH induced a transient up-regulation of p53 expression and NER in human primary normal fibroblasts and a concomitant decrease in UVC sensitivity. In contrast, in tumour cells hypoxia coupled to low pH resulted in a delayed, but not absent up-regulation of NER, which was p53-independent and did not result in a decrease in UVC sensitivity. We report here that it is the early transient p53-dependent up-regulation induced by hypoxia coupled to acidosis in human primary normal fibroblasts that may play a significant role in cellular UVC sensitivity. These data suggest a different cellular NER response to hypoxia compared to hypoxia coupled to low pH. The NER response to hypoxia and hypoxia coupled with acidosis was also different in primary cells when compared to tumour-derived cells. It was demonstrated that expression of dominant-negative HIF-lα in rat prostate tumour cells results in a reduction in host cell reactivation (HCR) of a UV-damaged reporter gene when compared to that in wild-type HIF-lα cells under normoxic conditions suggesting that basal HIF-lα expression may play an important role in NER. In addition we showed that hypoxia induced an up-regulation of NER in human primary normal fibroblasts that was delayed, but not absent in TCR-deficient CSB cells, suggesting a role for hypoxia in up-regulation of the GGR pathway of NER of a UVdamaged reporter gene. In contrast, HIF-lα-overexpression under conditions of hypoxia resulted in a down-regulation of NER in normal fibroblasts, which was delayed, but not absent in CSB fibroblasts. These results suggest that HIF-1α and CSB are involved in a hypoxia-induced NER response. This work provides further evidence that both GGR and TCR are p53-dependent. In addition, this study provides evidence that hypoxia and hypoxia coupled to acidosis can up-regulate NER in both primary and tumour cells, and that HIF-lα and the CSB protein play an important role in a hypoxia-induced NER response.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Fetal and Neonatal Nicotine Exposure: Effects on Pancreatic Beta Cells

contributor:
Holloway, Alison C.
Medical Sciences

subject: fetal, metabolic, nicotine, neonatal, pancreatic, beta, cell function, dysglycemia

abstract:
 Fetal exposure to cigarette smoke is associated with an increased risk of adult-onset metabolic abnormalities. In Canada, nicotine replacement therapy (NRT) is recommended as a safe smoking cessation aid for pregnant women. However, our laboratory has demonstrated that fetal and neonatal nicotine exposure results in glucose intolerance in adult rats. The goal of this thesis was to determine the mechanism(s) underlying the observed dysglycemia following fetal and neonatal nicotine exposure, with a specific focus on the effects of nicotine on pancreatic development and postnatal beta cell function.

 Nulliparous female Wistar rats received daily subcutaneous injections of either saline or nicotine bitartrate (1 mg/kg/d) for 2 weeks prior to mating until weaning (postnatal day 21 - PND21 ). Pancreatic tissue was collected from male offspring at birth (PND1), 3, 7, 15 and 26 weeks of age. For the critical windows study, dams received nicotine or saline during different stages of pancreatic development, including: A) pre-mating only, B) pre-mating + pregnancy only, C) pre-mating, pregnancy and lactation, or D) pre-mating + lactation only. For the intervention study, nicotine-exposed dams received either normal chow or diet containing antioxidants (1000 IU/kg vitamin E, 0.25% w/w coenzyme Q10 and 0.05% w/w α-lipoic acid) during mating, pregnancy and lactation.

 Results from this thesis demonstrate that exposure to nicotine during both fetal and neonatal development (but neither stage alone) causes a permenant loss of beta cell mass beginning at birth, and adult-onset dysglycemia in rodents. Furthermore, nicotine exposure induces pancreatic oxidative stress and mitochondrial-mediated beta cell apoptosis in neonates, followed by a progressive decline in mitochondrial structure and function. Maternal treatment with a dietary antioxidant cocktail during pregnancy and lactation protected the developing beta cells from nicotine-induced apoptosis and mitochondrial swelling. These data indicate that the safety of NRT use during pregnancy should be re-evaluated.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Systematic Approach for Control Structure Design

contributor:
Marlin, T.E.
Chemical Engineering

subject: control, structure, closed-loop, systematic, Mixed Integer Nonlinear Programming(MINLP), design

abstract:
 Control structure design is an essential step in control system synthesis and has big impact on achievable closed-loop performance. This thesis develops a systematic approach of selecting optimal control structures based on closed-loop dynamic performance and other criteria, such as integrity.

 The main contribution of this thesis is a rigorous mathematical formulation for control structure design problem that includes full closed-loop transient analysis with additional integrity requirement. The multi-objective framework is extendable so that different control performance objectives can be easily added. Unique process requirements and engineer inputs can be taken into account as additional constraints. The proposed formulation is a Mixed Integer Nonlinear Programming (MINLP) with complementarity constraints. The research scope is limited to linear process models and linear controller algorithms.

 The tailored solving strategy that makes this challenging problem computationally tractable is introduced in this thesis. The modified Branch and Bound algorithm takes advantage of the special problem structure by using control knowledge to generate valid lower bound efficiently. Prior knowledge can be cooperated as heuristic tuning parameters to guide the solving process so that a reasonably good solution can be found early in the solving process. The complexity study shows the solving strategy can attack
design problem size up to 8x8. Considering the percentage of good structures needing evaluation will decrease with problem size even larger problems will be tractable.

 The common control structures in process industries, such as square and nonsquare Single-Input-Single-Output (SISO) loop pairing using PID controller and block-centralized structure using Model Predictive Controller (MPC), are addressed in this thesis. The usefulness of this research has been demonstrated by several case studies, include Tennessee Eastman problem. The proposed methodology finds a physically sound pairing with good performance for Tennessee Eastman problem in less than one hour, while several off-the-shelf NLP, MINLP and global solvers cannot find a solution in five days.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Effect of Masonry Infill On The Seismic Behaviour of Reinforced Concrete Moment Resisting Frames

contributor:
Ghobarah, Ahmed
Civil Engineering

subject:
moment resisting frame
lateral load
resisting system
modern structure
buildings
industrial structures
ductile
seismic loads
moment
shear
force
stress
failure
buckle
Infill walls
earthquakes
Frame-infill
brittle
deformation
frames
cracks

abstract:
 A moment resisting frame is one of the most commonly used lateral load resisting system in modem structures because it is suitable for low and medium rise buildings and industrial structures. It can be designed to behave in a ductile manner under seismic loads.

 Masonry infills have traditionally been used in buildings as partitions and for architectural or aesthetic reasons. They are normally considered as non-structural elements, and their effect on the structural system has been ignored in the design. However, even though they are considered non-structural elements, there is mounting evidence that they interact with the frame when the structures are subjected to lateral loads
Infill walls have been identified as a contributing factor to catastrophic structural failures during earthquakes. Frame-infill interaction can induce brittle shear failures of reinforced concrete columns by creating a short column. Furthermore, infills can over-strengthen the upper stories of a structure and when they fail a soft first storey is created, which is highly undesirable from the earthquake resistance standpoint.

 There is a need for an efficient and accurate computational model to simulate the nonlinear hysteretic force-deformation behaviour of masonry infills, which is also suitable for implementation in time-history analysis of large structures. The aim is to develop a simplified advanced and cost-effective model for nonlinear time history analysis and seismic design of masonry infill frame structures.

 The objective of this research was to develop a practical and economical technique applicable for global analysis of general three-dimensional reinforced concrete infilled frames under lateral loads. Novel finite element model for the infill and the surrounding frame was developed using a special finite element configuration to represent the masonry panel. Some prescribed failure planes in different directions were defined depending on the common failure mode of masonry panels. Moreover, some of contact elements were used on the failure planes to connect among the panel elements, and between the panel elements and the boundary reinforced concrete frame. Different material models were used to represent the behaviour of concrete, reinforcing steel, mortar joints and inclined saw-tooth cracks in the infill panel. Different material models were used to describe the behaviour through and perpendicular to the prescribed failure planes. The proposed model and the used material models were described in details in the first part of this research.

 The proposed finite element model was verified against experimental and analytical results previously published by others. Different frames configurations, reinforcing details, boundary conditions and material properties were consider in that section to verify the capability of the proposed model to simulate the behaviour of different frames. The overall behaviour "Load-deflection relationship", failure point and failure mode were compared with the experimental and analytical results. Satisfactory agreement with the previously published results was obtained.

 The study investigates the capability of the proposed model to simulate the behaviour of infilled frames subjected to cyclic loads. Hysteretic loops obtained by using the new model were verified against experimental and analytical results and good correlation were obtained. The failure modes and crack patterns were compared with the experimental results and good agreements were obtained. The proposed model failed to capture some shear cracks in the RC frames as per the experimental results.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: LXR Regulation And Function In Human Airway Smooth Muscle

contributor:
Capone, John P.
Biochemistry and Biomedical Sciences

subject: liver X receptors, nuclear hormone receptor, NHR, oxysterols, cholesterol homeostasis, lipid transport, metabolism, inflammation, PKC, hASM, crucial effector cell, asthma progression, ABCA1, ABCG1, cytokines,

abstract:
 The liver X receptors (LXRs) are members of the nuclear hormone receptor (NHR) superfamily of transcription factors and are activated by oxysterols. As such, LXRs act as "cholesterol sensors" and play an integral role in cholesterol homeostasis by modulating the expression of genes involved in lipid transport and metabolism as well as inflammation.

 This thesis begins by describing the modulation of LXR transactivation by PKC. Specifically, transactivation by LXRα is decreased upon activation of PKC signalling pathways as assessed by LXR reporter gene analysis and endogenous target gene expression. These findings reveal a mode of regulation of LXRα that may be relevant to disease conditions where aberrant PKC signalling is observed.

 The second and third part of the thesis turns the attention to the role of LXR in human airway smooth muscle (hASM), a crucial effector cell in asthma progression. For the first time, research described here indicates that primary human ASM cells express functional LXRs. Moreover, LXR target genes ABCA 1 and ABCG I were highly induced upon the addition of LXR agonists leading to enhanced cholesterol efflux to apoAI and HDL, a process dependant entirely on ABCA I. Furthermore, activation of LXR inhibited the expression of multiple cytokines in response to inflammatory mediators and inhibited the proliferation and migration of hASM cells, two important processes that contribute to the airway remodelling observed in the asthmatic lung.

 This body of work suggests that modulation of LXR offers prospects for new therapeutic approaches in the treatment of asthma. Furthermore, it establishes a critical role for ABCA 1 in lipid transport in ASM cells and suggests that dysregulation of cholesterol homeostasis in these cells may be important. These findings have broad implications in the association of hypercholesterolemia and AHR and places LXR at the forefront of novel therapeutic avenues to treat inflammatory lung disease.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Seductive Claim: Constructing Deviance, Attraction and Social Problems

contributor:
Pawluch, D.A.
Sociology

subject: social, constructionist, deviance, crime, seductive,

abstract:
 This dissertation is composed of three essays that employ a social constructionist
perspective to critically examine the way in which sociologists, criminologists and
laypeople alike construct their subjects of study. Specifically, each essay examines how
claimsmakers establish the "facts of the matter" and construct the frames within which
social actors can experience their social realities. In doing so, the essays demonstrate that
those who are engaged in analyzing and addressing social problems, crime and deviance
act as claims makers engaged in constructing the realities they study.

 The first of the essays examines the way in which sociologists and criminologists
construct deviance and crime through the popular concept of "techniques of
neutralization." The author demonstrates how the neutralization concept requires analysts
to frame the speech of their subjects in a way that reinforces the deviant label. In doing
so, analysts' claims about neutralizing behavior are made sensible.

 The second essay focuses on a subculture of male pickup artists. It examines how
members of the subculture use evolutionary psychology in their claims about how to
attract and seduce women. How these men construct their reality using evolutionary
science provides further insights into the processes by which people are constructed and
how science is employed in the construction of social problems.

The third essay offers a commentary on the social constructionist approach itself.
The author considers the process by which social constructionists themselves define
constructionist theories and construct the boundaries of what constitutes legitimate
constructionist research.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Transcendence, Kenosis and Enfleshment: Charles Taylor's Religious Thought

contributor:
Kroeker, P. Travis
Religious Studies

subject: ethics, epistemology, religious, Charles Taylor, transcendence, enfleshment

abstract: The dissertation examines an intersection of ethics, epistemology, politics, and religious consciousness in the work of Canadian political theorist Charles Taylor. The goal of the study is to bring to light the central or even unifying role of theism in Taylor's broader philosophical project. More specifically, the dissertation speaks to the constructive moral and anthropological-as opposed to any merely ideological-role that theism plays in Taylor's thought, focusing especially on the conception of transcendence that underwrites his political and ethical theory. A basic claim of the dissertation is that Taylor's conception of transcendence, while remaining attentive to the demands of religious pluralism, has a kenotic shape that gives rise to an ethics that emphasizes enfleshed enactments of agape.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Deontic Action Logics for Specification and Analysis of Fault-Tolerance

contributor:
Maibaum, T.S.E.
Computer Science

subject: fault-tolerant, computing systems, axiomatic, deontic, logics, deductive system,

abstract:
 In this thesis we develop a mathematical framework to express and reason about properties of fault-tolerant computing systems. The main idea behind this mathematical framework is to use axiomatic theories to specify systems. The standard logical operators allow us to describe the basic behavior of the system, while we use deontic predicates on actions to express prescriptions about the system's behavior. Deontic logics have proved to be useful for reasoning about legal and moral systems, where the situation is more or less similar to fault-tolerance: there exists a set of rules that states what the normal behaviours or scenarios are. Violations arise when these rules are not followed and, as a consequence, some actions must be performed to return to a normal or desirable state. We develop our own deontic logic, keeping in mind that we want to use it for specifying fault-tolerant systems. We investigate the properties of this logic, commenting on those that are relevant to the use of the logic in practice. We provide two different deductive systems; one of them is a standard (Hilbert style) deductive system, while the other one is a tableaux system, which can be applied automatically to prove properties of specifications.

 In any specification language, it is important to have at hand mechanisms which enable designers to modularize the system description; we investigate how to apply these mechanisms to the logics proposed in this thesis, and, in particular, we focus on how the modularization of specifications affects the local prescriptions of a module (or component). We study the problems that arise from the interaction between components. We show that, in some cases, we can guarantee that the locality of violations in a particular component is preserved. Some examples are provided throughout this thesis to illustrate how the ideas described below can be applied in practice.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Correlative Spect Imaging Of Neural Stem/Progenitor Cell Transplants In A Rat Model Of Parkinson's Disease

contributor:
Doering, L.C.
Medical Sciences

subject: Cell Therapy, Parkinson's, Disease, dopamine system, cell replacement, transplantation, NSPCs, Neural stem/progenitor cells, technetium-99m, cells, photon, SPECT, DNA

abstract:
 Cell therapy for Parkinson's disease will greatly benefit from progress in methods aimed at visualizing the dopamine system and cell replacement techniques. Currently, cell therapy has been met with varied success, in part due to differences in cell sources, transplantation procedures, and our lack of understanding of cell fate post-transplantation. The standardization of transplantation procedures will enhance our ability to draw comparisons between studies and improve cell therapy outcomes. We developed a method to label neural stem/progenitor cells (NSPCs) with technetium-99m and then visualize the cells with single photon emission computed tomography (SPECT) subsequent to grafting in the brain. This labeling method permitted a high uptake of the tracer into the cells without causing damage to the DNA or altering cell viability. The labeling caused a significant decrease (75%) in the proliferative capacity of the SPCs and caused a trend towards an increase in neuronal differentiation. Using this technique paves the way to standardize the location of the transplant and quantify the number transplanted cells while increasing the production of neurons.

 Experiments were performed to visualize the dopamine system with [(123)I]altropane at pre-and post-transplant time points in the 6-0HDA rat model of Parkinson's disease. [(123)I]altropane binding correlated with the content of dopamine in the stria tum. However, [(123)I]altropane binding was not correlated with dopamine content in the substantia nigra and did not show a correlation with the amphetamine rotations. However, there was a significant correlation with the cylinder test and the postural instability test. When the data was assessed using linear regression, the r^2 value of the linear relationship was low indicating that [(123)I]altropane SPECT is not a good predictor of behavioural outcome due to a weak linear relationship. Our data indicates that [(123)I]altropane predicts the integrity of the striatal dopamine nerve terminals, but does not predict the integrity of the nigrostriatal system. The results are discussed in relation to the use of [(123)I]altropane in comparison to other dopamine SPECT and PET agents.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: IMPLEMENTING EFORM-BASED BASELINE RISK DATA EXTRACTION FROM HIGH QUALITY PAPERS FOR THE BRISKET DATABASE AND TOOL

contributor:
Iorio, Iorio
eHealth

subject:
Baseline Risk
Data Extraction
Database
Primary Literature
McMaster PLUS Database

abstract:
This thesis was undertaken to investigate if an eForm-based extractor interface would improve the efficiency of the baseline risk extraction process for BRiskeT (Baseline Risk e-Tool). The BRiskeT database will contain the extracted baseline risk data from top prognostic research articles. BRiskeT utilizes McMaster University’s PLUS (Premium Literature Service) database to thoroughly vet articles prior to their inclusion in BRiskeT. The articles that have met inclusion criteria are then passed into the extractor interface that was developed for the purpose of this thesis, which has been called MacPrognosis. MacPrognosis displays these articles to a data extractor who fills out an electronic form which gives an overview of the baseline risk information in an article. The baseline risk information is subsequently saved to the BRiskeT database, which can then be queried according to the end user’s needs.
One of the goals in switching from a paper-based extraction system to an eForm-based system was to save time in the extraction process. Another goal for MacPrognosis was to create an eForm that allowed baseline risk information to be extracted from as many disciplines as possible. To test whether MacPrognosis succeeded in saving extraction time and improving the proportion of articles from which baseline risk data could be extracted, it was subsequently utilized to extract data from a large test set of articles. The results of the extraction process were then compared with results from a previously conducted data extraction pilot utilizing a paper-based system which was created during the feasibility analysis for BRiskeT in 2012.
The new eForm based extractor interface not only sped up the process of data extraction, but may also increase the proportion of articles from which data can be successfully extracted with minor future alterations when compared to a paper-based model of extraction.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Impact Of Cigarette Smoke Exposure On Pathways of Microbial-Induced Pulmonary Inflammation

title: Impact Of Smoke On Microbial-Induced Pulmonary Inflammation

contributor:
Stampfli, M. R.
Medical Sciences

subject:
cellular
molecular
genetic mechanisms
pathogenesis
Chronic Obstructive Pulmonary Disease
COPD
microbial infection
cigarette
smoke
exposure
alveolar macrophages
antigens
cytokines

abstract: The cellular, molecular, and genetic mechanisms underlying the pathogenesis of Chronic Obstructive Pulmonary Disease (COPD) are not well understood. The purpose of this thesis was to address the hypothesis that microbial infection is important for the development and/or progression of COPD through investigation of how cigarette smoke alters the response to a bacterial challenge in a mouse model of cigarette smoke-exposure. To this end, in chapter 2 of this thesis we tested the hypothesis that cigarette smoke-exposure attenuates the ability of alveolar macrophages to sense microbial antigens through innate pattern recognition receptors. The central point of this study was the observation that alveolar macrophages isolated from cigarette smoke-exposed mice had attenuated expression of typical inflammatory cytokines following microbial stimulation. Building on this main observation, in chapter 3 we questioned what the consequences of this would be to an in vivo bacterial challenge with nontypeable Haemophilus influenzae. We demonstrated that cigarette smoke-exposure resulted in chronic inflammation, this inflammation was exacerbated following bacterial challenge, and perhaps most importantly, the nature of the inflammatory response was altered. Interestingly, an observation from the study in chapter 3 indicated that exacerbated inflammation in cigarette smoke-exposed mice may be beneficial for clearance of the bacteria, but may come at the expense of damage to the lungs. Consequently, in chapter 4 we questioned the strain and dose/ frequency stringencies of cigarette smoke-exposure on the observation of accelerated bacterial clearance. We demonstrated a role for antibodies in bacterial clearance. Collectively, this thesis provides insight into our understanding of COPD by demonstrating that cigarette smoke-exposure alters the pulmonary immune/ inflammatory response to a microbial challenge, which has a detrimental impact on the lungs.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: New Advances in High-quality Screening by Capillary Electrophoresis: A Unified Platform for Thermodynamic and Kinetic Characterization of Protein-Small Molecule Interactions

contributor:
Britz-McKibbin, Philip
Chemistry and Chemical Biology

subject:
high-quality screening
capillary electrophoresis
enzymatic
thermodynamic
biomolecular interactions
protein
isomerase enzymes
dynamic ligand exchange-affinity
electrophoresis
DLE-ACE
cAMP
derivatization

abstract: The development of high-quality screening assays for the identification of biologically active ligands is critical in drug discovery. This thesis is aimed at developing new advances m capillary electrophoresis (CE) for the characterization of the conformational stability and enzymatic activity of protein targets with small molecules. CE provides a convenient platform for unbiased assessment of multiple thermodynamic and kinetic parameters associated with biomolecular interactions involving regulatory protein or isomerase enzymes, where various sample pretreatment steps can be integrated directly in-capillary during analysis. The first two chapters of the thesis (Chapters II, III) outline the development of dynamic ligand exchange-affinity capillary electrophoresis (DLEACE) as a novel strategy for the screening of allosteric ligands based on the differential stability of urea-induced unfolding of various apolholo-protein states of cAMP receptor protein constructs. This work introduced a label-free and multivariate approach for ligand selection based on complementary thermodynamic parameters that allowed for determination of the dissociation constant of protein-ligand interactions over a wide dynamic range (> 10^4, Kd = nM-mM). The subsequent two chapters of the thesis (Chapters IV, V) describe the development of a novel kinetic assay for unbiased characterization of isomerase activity associated with D/L-amino acid metabolism using hydroxyproline epimerase as a model system. Stereoselective resolution of various hydroxyproline isomers was accomplished via off-line or on-line chemical derivatization with dynamic complexation usmg chiral selector(s) in order to screen potential inhibitors for putative epimerase and racemase activity. The integration of both thermodynamic and kinetic strategies for differentiation of mutant from wild-type enzymes was important for revealing the function of a catalytic acid/base cysteine pair in the epimerase active site. Overall, this thesis outlines an integrative framework based on CE for high-quality screening, which is relevant in reducing the high attrition rate of lead candidates in drug development.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Growth of Nanowires on GaAs (100) Substrate

contributor:
LaPierre, Ray R.
Kruse, Peter
Engineering Physics

subject: growth, GaAs (100), nanowires, topography, particle

abstract:
 Using gold as seed particles, the vapour-liquid-solid (VLS) growth of GaAs nanowires by
molecular beam epitaxy on GaAs (100) substrates was investigated with a view to
understanding and controlling the growth directions of nanowires. The crystallographic
orientation as well as surface density of nanowires was found to be significantly affected
by surface topography resulting from surface preparation prior to nanowire growth.
Elongated pits of varying dimensions and orientation were formed on GaAs (100)
substrates depending on the interaction of GaAs with gold or surface oxide. An in-depth
analysis was carried out regarding the formation of pits as well as chemical composition
of the oxide layer during the seed particle formation process.

 By analyzing the orientation-dependent structural properties of nanowires at different stages of growth, the origin of multi-directionality of nanowires on GaAs (100) substrates has been explored, and it has been shown that the growth directionality of nanowires can be significantly triggered to either the <011> or <111> direction by optimizing the growth rate as well as size of seed particles. Crystallographic properties of nanowires have also been discussed with reference to their growth directions.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Chain Conformation and Nano-Patterning of Polymer Brushes Prepared By Surface-Initiated Atom Transfer Radical Polymerization

contributor:
Zhu, Shiping
Chemical Engineering

subject: polymerization

subject: atom transfer radical polymerization

subject: si-ATRP

subject: radical termination

subject: migration-termination

subject: POEGMA

subject: poly(methyl methacrylate)

subject: PMMA

subject: copolymer

subject: poly(2-(2-methoxyethoxy)ethyl methacrylate -co- oligo(ethylene glycol) methacrylate) (P(MEO(2)MA-co-OEGMA))

subject: silicon wafers

subject: neutron reflectometry

subject: NR

abstract:
 Over the past decade, the development of surface-initiated living polymerization methods has brought a breakthrough to surface modification owing to their control ability. Surface-initiated atom transfer radical polymerization (si-ATRP), as the most popular one, has been widely employed to give novel polymer structures and functionalities to various surfaces for the purposes of tailoring surface properties, introducing new functions, or preparing so-called "smart surfaces", which can respond to external stimuli such as solvent type, pH, temperature, electric and magnetic fields etc. In this thesis, the mechanistic study of the si-ATRP was first carried out through modeling to gain good understanding of si-ATRP. Si-ATRP was then employed to prepare different types of polymer brushes to produce "smart surfaces".

 The kinetic model was developed using the method of moment. Combined with experimental data, a quantitative analysis was carried out for the si-ATRP mechanism. All information of grafted polymer chains, including active chain concentration, radical concentration, chain length, polydispersity, was illustrated. A new radical termination mechanism, termed as migration-termination, was proposed for si-ATRP.

 Si-ATRP was then employed to graft poly(oligo(ethylene glycol) methacrylate) (POEGMA) block poly(methyl methacrylate) (PMMA) brushes on silicon wafer surfaces. Simple solvent treatment gave nanoscale patterns via the phase segregation of POEGMA and PMMA segments. Various patterns including spherical aggregates, wormlike aggregates, stripe patterns, perforated layers and complete overlayers, were obtained by adjusting the upper block layer thickness. Furthermore, these nanopatterns had a unique stimuli-responsive property, i.e., switching between different morphologies reversibly after being treated with selective solvents.

 POEGMA-block-poly(2-(methacryloyloxy)ethyl trimethylammonium chloride) (PMETAC) brushes, having two hydrophilic segments, were synthesized by si-ATRP method. A variety of nanopatterns and their stimuli-responsive ability were observed. The adsorption behaviors of fibrinogen on these patterns were thoroughly studied by ellipsometry, water contact angel measurement, AFM and radio labelling method.

A novel thermo-responsive copolymer, poly(2-(2-methoxyethoxy)ethyl methacrylate -co-oligo(ethylene glycol) methacrylate) (P(ME02MA-co-OEGMA)), was also grafted onto silicon wafers. Its thermo-responsive behavior and chain conformation in aqueous solution were studied by neutron reflectometry (NR). Both extended and collapsed brushes exhibited good protein adsorption resistance.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Interaction of Loading and Feeding on Skeletal Muscle Anabolic Signaling and Protein Turnover in Humans

contributor:
Phillips, Stuart M.
Kinesiology

subject: amino acids, skeletal, muscle, anabolic, protein, turnover

abstract: Resistance exercise and amino acids independently and synergistically stimulate muscle protein synthesis. Unloading of skeletal muscle depresses fasted state muscle protein synthesis, but the effect on the fed state response is unknown. Elucidation of the signaling pathways underlying the regulation of these processes in humans is in its infancy. Therefore, the purpose of this thesis was to determine how resistance exercise, feeding, and unloading interact to affect muscle protein turnover and its markers. In study 1 young men (N=9) underwent an acute bout of unilateral leg resistance exercise with or without feeding, with biopsies 6 h post exercise. Exercise dephosphorylated eiF2Bε and together with feeding potentiated the increase in phosphorylation of p70s6k and rps6. In study 2, 12 young people received primed constant infusions of 13C6-Phe in the fasted state and at one of two i.v. AA infusion rates (low, 42.5 mg/kg/h AA; high: 261 mg/kg/h AA) after 14 d of knee-brace mediated immobilization. Immobilization decreased fasted and fed state myofibrillar protein synthesis at both doses without obviously affecting translational signaling proteins. In study 3, two markers of muscle protein breakdown and oxidative damage were measured in 21 subjects (men, N=13, women, N=8) after 2 d and 14 d of knee-brace mediated immobilization. Protein ubiquitination was elevated after 2 d of immobilization but there was no sustained elevation in ubiquination at 14 d or increases in the 14kDa actin fragment or protein carbonyls and 4-hydroxy-2-nonenal. These studies support the concept that the responses of human muscle to changes in loading are primarily at the level of protein synthesis, and the p70 pathway appears to play a role in mediating the hypertrophic response. The currently known static markers of translational signaling and protein breakdown, however, are not very informative when attempting to account for an underlying molecular mechanism for disuse atrophy.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Comparative And Functional Genomics Of Actinobacteria And Archaea

contributor:
Gupta, Radhey S.
Biochemistry

subject:
Prokaryotes
phylogenetic trees
Actinobacteria
Archaea
phylogenetic
phylum

abstract: The higher taxonomic groups within Prokaryotes are presently distinguished mainly on the basis of their branching in phylogenetic trees. In most cases, no molecular, biochemical or physiological characteristics are known that are uniquely shared by species from these groups. Comparative genomic analyses are leading to discovery of molecular characteristics that are specific for different groups of Bacteria and Archaea. These markers include conserved inserts and deletions in universal proteins and lineagespecific proteins, which provide novel means for identifying and circumscribing these groups of prokaryotes in clear molecular terms and for understanding their evolution. Because of their taxa specificities, further studies on these newly discovered molecular characteristics should lead to discovery of novel biochemical and physiological characteristics that are unique to different groups of microbes. The focus of my project was phylogenomic studies for two large prokaryotic group: Actinobacteria and Archaea. My goals were to a) identify molecular markers that are specific to Actinobacteria and Archaea at different taxonomic levels, which will help to understand the phylogenetic relationship within these two major groups; b) understand the functional significance of Actinobacteria-specific proteins. By comparative genomics approach, a number of conserved indels in various proteins (viz. Coxl, GluRS, CTPsyn, Gft, GlyRS, TrmD, Gyrase A, SahH and SHMT) have been identified that are specific for all Actinobacteria and additional indels were found to be unique to its major subgroups, such as Corynebacterineae, Bifidobacteriaceae, etc. In parallel, a large number of proteins were discovered to be restricted to Actinobacteria at different phylogenetic depths. These identified conserved indels and proteins for the first time provide useful markers for defining and circumscribing the Actinobacteria phylum or its subgroups in clear molecular terms. Similar comparative genomic studies have been carried out on Archaea and a vast number of proteins have been identified that are unique to Archaea or its various lineages. Lastly, I have performed functional studies on one of the Actinobacteria-specific proteins (ASPl). The structure of ASPl was determined and structural comparison indicates that the function of this protein might be novel since it does not match any known protein with or without known function.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Disclosure of Intimate Partner Violence in Urban Emergency Department Settings: A Mixed Methods Study

contributor:
Ciliska, Donna
Nursing

subject: mixed, methods, partner, emergency, intimate, violence

abstract:
 This mixed methods study seeks to explain women's decision making regarding intimate partner violence disclosure in urban emergency departments. It contributed to an overall program of research led by Dr. H.L. MacMillan examining the effectiveness of screening in health care settings to reduce violence and improve the quality of women's lives.

 The study included a randomized, controlled trial with a quantitative sub-analysis and a grounded theory approach. The trial goal was to evaluate whether routine screening for IPV in health care settings, as compared to usual care, does more good than harm. The quantitative sub-analysis included 1,182 participants from three trial emergency departments. In the sample, 1.9% were exposed to intimate partner violence disclosed to the health care provider. Of those who disclosed, 62.9% were positive on both the screening tool and criterion standard. The grounded theory phase involved 19 participants and sought to examine the problems that trial participants associated with intimate partner violence disclosure and the processes they used to resolve them.

 "Being found out" was the basic social psychological problem that influenced women's decisions against disclosure. This led to a three-phase process where participants attempted to "minimize their risks." The basic social psychological process included: (a) deciding to seek health care, (b) evaluating trust in the clinician, and (c) establishing internal readiness for disclosure. Participants stated that the emergency department was not an ideal place to disclose violence due to overcrowding, chaos, long wait times, and a lack of privacy. Results indicated that abused women wanted clinicians to offer empathy and support, and to minimize the intrusion caused by assessment. Clinician education is required to improve communication, client engagement and comfort discussing intimate partner violence. Future research could explore the barriers and facilitators to care quality and patient satisfaction among abused women seeking emergency care.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Study of the Astrophysically Important States in 26 Si via the p(27Si,d)26 Si* Reaction and the p(25Al,p )^25Al Elastic Scattering

contributor:
Chen, Alan
Physics and Astronomy

subject: 26Al, states, elastic, scattering, reaction, rate, 26Si

abstract:
 The radioactive 26Al is an important probe for the interstellar medium of our galaxy since it is observed through the emission of 1.8 MeV gamma rays from the decay of 26gAl produced by the proton capture on 25Mg. But the production of the galactic 26Al is now still not well determined partially due to the lack of knowledge of the important states in 26Si which dominate the large uncertainty in the 25 Al(p,γ)26Si reaction rate at nova temperatures.

 In nova explosions, the proton capture of 25Al competes with its β decay and bypasses the production of 26gAl, since the capture product 26Si decays quickly to 26mAl instead of its ground state, without the emission of the 1.8 MeV gamma ray. But at even higher temperatures, such as in supernova explosions, 26mAl can be excited to the higher excited states by thermal excitation and then quickly de-excite to the ground state, thereby enhancing the production of 26gAl. The energy levels in 26Si in the Gamow window corresponding to these temperatures therefore need to be well understood in order to determine the 25Al(p,γ)26Si reaction rate, and thus the production rate of 26Al in these explosive environments.

 Two experiments were performed to study the important states in 26Si : one is the p(27Si,d)26Si* reaction at the NSCL, aiming to construct the level scheme of low lying states around the proton threshold; the other experiment is a measurement of the elastic scattering of 25Al+p with CRIB at RIKEN in order to obtain information on states in a broad range above the proton threshold. Details of these two experiments and their data analyses will be presented in this thesis.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: PREDICTIVE MODELS FOR DENGUE FEVER AND SEVERE DENGUE

contributor: Clinical Health Sciences (Health Research Methodology)

subject: : Dengue, fever, Predictive model, symptoms, Honduras,agreement,sensitivity, specificity,febrile illness

abstract: Predictive models based in symptomatology of suspected dengue patients seeking medical care in Honduras. The models based on logistic regression models predicted the outcomes of dengue fever/ severe dengue. Sensitivity and specificity are discussed. It also describe the level of agreement between Honduran classification of severe dengue and the ones based on World Health Organization guidelines of 1997 and 2009.

abstract:
Introduction: Dengue is a major public health problem in tropical and subtropical countries but its clinical presentation may be similar to many febrile illnesses. Since in endemic countries laboratory confirmation is frequently delayed, the majority of dengue cases are diagnosed based on patient’s symptomatology. This can often lead to misdiagnosis and potential serious health complications. The objective of this study was to identify clinical, hematological and demographical parameters that could be used as predictors of dengue fever among patients with febrile illness.
Methods: We conducted a retrospective cohort study of 548 patients presenting with febrile syndrome to the largest public hospitals in Honduras. Patients’ clinical, laboratory, and demographical data as well as dengue laboratory confirmation by either serology or viral isolation were used to build a predictive statistical model to identify dengue cases.
Results: Of 548 patients, 390 were confirmed with dengue infection while 158 had negative results. Univariable analysis revealed seven variables associated with dengue: male sex, petechiae, skin rash, myalgia, retro-ocular pain, positive tourniquet test, and bleeding gums. In multivariable logistic regression analysis, retro-ocular pain petechiae and bleeding gums were associated with increased risk, while epistaxis and paleness of skin were associated with reduced risk of dengue. Using a value of 0.6 (i.e., 60% probability for a case to be positive based on the equation values), our model had a sensitivity of 86.2%, a specificity of 27.2%, and an overall accuracy of 69.2%; allowing for the diagnosis of dengue to be ruled out and for other febrile conditions to be investigated.
Conclusions: The application of predictive models can be valuable when laboratory confirmation is delayed. Among Honduran patients presenting with febrile illness, our data reveal key symptoms associated with dengue fever, however the overall accuracy of our model is still low and specificity remains a concern. Our model requires validation in other populations with similar pattern of dengue transmission.

Key Words: Dengue, fever, Predictive model, symptoms, Honduras

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Unambiguous Functions in Logarithmic Space

contributor:
Soltys, Michael
Computing and Software

subject: unambiguity, space-bound, Turing, logarithmic,

abstract:
 The notion of nondeterminism is one of the most fundamental concepts in many areas of computer science. Unambiguity, requiring that there be at most one correct sequence of nondeterministic choices, has proved to be one of the most meaningful restrictions of nondeterminism. In the context of space-bounded Turing Machines, several variants of unambiguity have been proposed and studied, and some interesting results have been established, narrowing slightly the gap between deterministic and nondeterministic logarithmic-space computation.

 We study the different variants of unambiguity in the context of computing multi-valued functions (as opposed to the usual yes/no decision problems). We propose a modification to the standard computation models of Turing Machines and configuration graphs, which allows for unambiguity-preserving composition. We introduce a unified notation, capturing the different flavors of ambiguity. Furthermore, we define a notion of reductions (based on function composition), which allows non-determinism but controls its level of ambiguity. In the light of this framework we establish some reductions between different variants of path counting problems. We also investigate more carefully the technique of inductive counting, and obtain improvement of some existing results.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Heart Failure Patients' and Primary Caregivers' Emotions

contributor:
Arthur, Heather M.
Nursing

subject: emotional, distress, patients, heart failure, caregivers, depression

abstract: Background: There is strong evidence to suggest that emotional distress, particularly depression, is common in patients with heart failure (HF). Caregivers of patients with HF play a pivotal role in improving HF patient outcomes; however, these caregivers are at risk for caregiver burden and emotional distress. Objectives: The objectives of this study were to explore potential relationships among patient and caregiver emotional status, uncertainty and caregiver appraisal. For the purposes of this study, emotional distress is defined as the presence of symptoms of anxiety or depression. Methods: Using a longitudinal exploratory design, 48 HF patient-caregiver pairs were recruited. Patients and caregivers completed the Hospital Anxiety and Depression Scale, Mishel Uncertainty in Illness Scale (MUIS) and caregivers also completed the Caregiver Reaction Assessment at baseline, 2 months and 4 months. Results: Patients had advanced HF symptoms and were older than caregivers (mean age 72.6 years, 54% male versus mean age 58.4 years, 54% female). The majority of caregivers were spouses (58%) but many were adult children (42%). There were significant relationships between: a) HF patient and caregiver uncertainty, and b) caregiver emotional distress and caregiver burden. There were no significant relationships between: a) patient and caregiver symptoms of anxiety and depression, b) emotional distress and uncertainty, or c) patient emotional distress and caregiver burden. Over time, there was a trend for a decrease in: a) patient symptoms of depression, b) caregiver symptoms of anxiety, and c) patient and caregiver uncertainty. Conclusions: Contrary to findings in other studies, there was no significant relationship between symptoms of anxiety and depression in patients and their primary caregivers. There was no relationship between emotional distress and uncertainty; however, this is one of the first studies using the MUIS in HF patients and caregivers and further research with this tool is needed. Finally, this study supports findings from other studies suggesting a strong relationship between caregiver emotional distress and caregiver burden.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Neutron Scattering Measurements of Low-Dimensional Quantum Systems

contributor:
Gaulin, Bruce D.
Physics

subject: low-dimensional, quantum, magnets, superconductivity, systems, scattering,

abstract:
 Low dimensional quantum magnets which display a collective singlet ground state and a gap in their magnetic excitation spectrum provide a framework for much exotic phase behavior in new materials, with high temperature superconductivity being the best appreciated example. Neutron scattering techniques can be applied to study a wide variety of problems in condensed matter physics. These techniques are particularly useful as applied to understanding the magnetic properties of quantum magnets that display exotic phases.

 SrCu2(BO3)2, is a rare example of a two-dimensional quantum magnet for which an exact theoretical solution describing its ground state is known to be a collective singlet. Previous high resolution neutron scattering measurements identified the most prominent features of the spin excitation spectrum in SrCu2(BO3)2, including the presence of one and two triplet excitations and weak dispersion characteristic of subleading terms in the spin Hamiltonian.

 The resemblance between the spin gap behavior in the Mott insulator
SrCu2(BO3)2 and that associated with high temperature superconductors motivated the consideration of the significance of doping in order to understand the properties of this quantum magnetic system. For this reason, a series of neutron scattering studies on doped SrCu2(BO3)2 were initiated.

 These series of investigations began with the performance of neutron scattering measurements on a SrCu(2-x)Mgx(BO3)2 single crystal in order to introduce magnetic vacancies to the system. These results revealed the presence of new spin excitations within the singlet-triplet gap of this system. Application of a magnetic field induces Zeeman-split states associated with un-paired spins which exist as a consequence of doping with quenched non-magnetic impurities. Additional substantial broadening of both the one and two triplet excitations is observed in the doped system as compared to the pure system. Theoretical calculations are shown to qualitatively account for these features.

 These studies were extended to neutron scattering measurements on
Sr(1-x)LaxCu2(BO3)2, with an aim of introducing charged carriers into this system. The broadening of the one and two triplet excitations is observed and compared to the thermally induced finite lifetime of the pure system. The temperature dependence of this broadening in Sr(1-x)LaxCu2(BO3)2 is different compared to that observed in both SrCu2(BO3)2 and SrCu(2-x)Mgx(BO3)2.

 It has also been suggested that there is a relation between the spin-lattice interaction in SrCu2(BO3)2 and the magnetic dynamics at low temperatures and high magnetic fields. For this reason there has been increased interest in the study of the crystalline structure and vibrational modes of SrCu2(BO3)2. In order to investigate the role of the lattice in the formation of the singlet ground state in SrCu2(BO3)2, a series of low and high energy neutron scattering measurements were carried out on this system to study both the crystalline structure as well as the normal modes of vibration of the lattice, the transverse acoustic and optical phonons. Transverse acoustic phonons with energies comparable to and higher than the onset of the two triplet continuum show substantially increased lifetimes on entering the singlet ground state below ~ 10 K. This may indicate the removal of the decay channel for the phonons due to the gapping of the spin excitation spectrum in SrCu2(BO3)2 at low temperatures. In high energy inelastic neutron scattering we observe broadening of optic phonons in the ~ 52 to 65 meV region on entering the low temperature singlet ground state.

 Additionally, the magnetic properties of CuMoO4, which is a triclinic quantum magnet system based on S=1/2 moments at the Cu2+ site, were studied using elastic and inelastic neutron scattering experiments. This material exhibits a first order structural phase transition at ~ 190 K as well as a magnetic phase transition at ~ 1.75 K. We were primarily interested in the low temperature magnetic properties of this material. Magnetization and heat capacity measurements as well as elastic and inelastic neutron scattering measurements were conducted on this system within the low temperature ordered phase. These studies confirm that this material has a magnetic phase transition at ~ 1.7 K. Neutron scattering results indicate that this magnetically ordered phase is characterized by a doubling of the a axis. Inelastic neutron scattering measurements revealed a gapped magnetic excitation spectrum in zero magnetic field, which could be filled in by the application of magnetic fields approaching 7 T.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Constructions of the Family in Livy's Ab Urbe Condita

contributor:
Bradley, K.
George, M.
Haley, E.
Classics

subject: Livy's Ab Urbe Condita, Rome, family, relationships, traditional, morality

abstract: Livy's Ab Urbe Condita, a history of Rome from its foundations to his own day, has been the subject of much scholarly analysis and criticism. The 35 extant books are primarily a political and military narrative in the tradition of Roman historiography, written at the end of the period known to us as the Republic and in the early decades of Rome's imperial period (ca. 30 BC--14 AD). What is remarkable about the work is the volume of stories and incidental references to family relationships and family life, particularly marriages and parent-child relationships, which often have little bearing on political or military activities. Throughout the AUC, Livy constructs consistent representations of family ideals according to the features of traditional morality that were dominant during his own day, applying them even to periods in which Roman society was likely quite different. His stories include emphatic and vivid exempla of traditionally appropriate behaviour between husbands and wives and in sexual behaviour as well as reciprocal duties between parents and their children. The explanations for Livy's keen interest in family relationships lie both in his own background and in the socio-political turbulence of the period during which he matured and began to write his history. During this same period, Augustus rose to political prominence and invoked a similar set of moral values in his programme of cultural renewal, in legislation as well as visual culture. The elements of this programme can be usefully compared to Livy's constructions of family ideology to further inform and articulate the scope of moral concerns which were of interest to politically and culturally active Romans of the first century BC.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Miniaturization of Time-Gated Raman Spectrometer with a Concave Grating and a CMOS Single Photon Avalanche Diode

contributor:
Deen, M. Jamal
Biomedical Engineering

abstract:
Raman spectroscopy possesses the important advantages of non-contact and non-destructive properties in chemical analysis applications. Commercial bench-top Raman spectrometers are bulky, expensive, and limited to laboratory use. Handset Raman spectrometers are commercially available, but still expensive. To extend its field applications such as water quality monitoring and pharmaceutical analyses, there is a growing need for cost reduction and system miniaturization of Raman spectrometers.
      This work focuses on designing and building a compact and low-cost Raman spectrometer. A key issue of a Raman spectrometer is the detection of a weak Raman signal, especially when a strong fluorescence signal is present. Therefore, challenges in this work include system miniaturization and designing a low-cost and sensitive detection system to measure the weak Raman signal.
      System miniaturization is approached using a concave grating based wavelength selector. A concave grating could perform both functions of light wavelength separation and focusing without the need for extra mirrors, reducing system size and complexity. The concave grating is designed and fabricated on plano-concave lenses by a low-cost custom holographic technique. Characterization of the custom concave grating proves its light wavelength separation and focusing properties.
      Addressing cost reduction, a CMOS single photon avalanche diode (SPAD) is selected for its low cost and capability of detecting low intensity light. To achieve fluorescence suppression, the SPAD is operated in the time-gated (TG) mode. The TG-SPAD is implemented in a 130nm standard CMOS technology. Fast gating, generation and readout circuits are designed to gate the SPAD at frequencies up to 100MHz, with a short gate window of 3.5ns. Negligible afterpulsing probability (<1%) for hold-off times longer than 16ns is obtained.
      A time-gated spectrometer prototype is built combining the concave grating and TG-SPAD. The system achieves timing resolution better than 60ps. Fluorescence suppression is observed by narrowing the detection window of the TG-SPAD, and Raman peaks of Rhodamine B are resolved by the system. The time-gated fluorescence lifetime measurement further proves the efficiency and fluorescence imaging capabilities of the proposed system.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A March From Selma to Canada: Canada and the Transnational Civil Rights Movement

contributor:
Frager, Ruth
History

abstract: This dissertation examines transnational connectivities centred on anti-discrimination and human rights activism, discourse, and policy spanning the Canada-United States border during the 1950s and 1960s. It focuses specifically on Canadian interactions with the African American civil rights movement, with particular attention to the ways Canadian activists contributed to the American movement, as well as the significance of the American movement to Canadian rights activism and policy. This dissertation contributes to historical understanding of the transnational nature of the American civil rights movement by illustrating how Canadian activists and organizations impacted directly on the American movement through financial and moral support. It also argues the American movement had important implications for Canadian rights activism and policy. Canadian anti-discrimination activists followed American civil rights campaigns, adapting ideas and techniques when relevant to their own efforts. Most significantly, they leveraged examples from south of the border and elsewhere around the world when pressing for change in local contexts. Through their local and global efforts, Canadian activists achieved notable successes in pushing Canadian public policy towards stronger human rights protections. While generating pressure for change, the international framework acted simultaneously as a restraining force on more fundamental transformations in conceptualizations of human rights in Canada. Many Canadians observed the civil rights movement from a sanctimonious perspective, denying that international examples carried applicability for their own country. Whether acting as a pressure for strengthened human rights protections, or a restraining force against the advent of more fundamental measures, this dissertation argues that Canadian human rights activism, discourse, and policy in the 1950s and 1960s can only be fully understood when intersections between local, national, and global contexts are considered.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Investigating gas phase processes in natural and hydrocarbon-contaminated groundwater

contributor:
Smith, James E.
Roy, James W.
Earth and Environmental Sciences

subject:
Shallow Groundwater
Trapped Gas
Pilot-Scale Tank
Time Domain Reflectometry
Total Dissolved Gas Pressure

abstract:
Here the nature of gas phase processes and their implications for flow and transport were examined using a pilot-scale, 2-dimensional, laboratory tank instrumented for direct, in situ trapped gas measurements. Experimental conditions mimicked an unconfined, homogeneous sand aquifer with horizontal flow. Key areas of investigation included i) trapped gas dissolution following a water table fluctuation; and ii)  gas phase dynamics within a hydrocarbon plume experiencing dissolved gas production via biodegradation.
In the first experiment, dissolution occurred as a diffuse, wedge-shaped front propagating down-gradient in the tank over time, with enhanced dissolution at depth. Front advancement at the deepest monitoring point was 4.1 - 5.7x faster. This dynamic, depth-dependent pattern was mainly attributed to increased dissolved gas solubility. An estimated 12% increase in quasi-saturated hydraulic conductivity (Kqs) also contributed to greater dissolution at depth. Overall, the dissolution front near the water table advanced 1 m down-gradient in 344 days, suggesting that gas trapped shallowly will likely persist for significant periods of time. The utility of total dissolved gas pressure sensors for simple in-well measurements to detect trapped gas and monitor its dissolution were also demonstrated.
During the second experiment, biodegradation occurred under variable redox conditions, ranging from denitrification to methanogenesis. Significant in situ increases in trapped gas were observed within the tank over 330 days. Maximum gas saturations never exceeded 27% of pore volume even during continued dissolved gas production, indicating ebullition upon reaching a gas phase mobilization threshold. Consequently, associated reductions in Kqs were restricted to a factor of 2 or less, but still appeared to alter the groundwater flow field. While trapped gas increases within the biodegradation plume were expected, declines in gas saturations were also observed. Thus, the overall pattern of trapped gas growth exhibited high spatial and temporal variability. Influencing factors included changes in hydrocarbon inputs and microbial controls on redox zonation, in addition to ebullition and changes in groundwater flow; emphasizing that gas phase growth in contaminant plumes will be highly complex and dynamic in the natural systems.
Given the impacts on hydraulic conductivity, and the fate and transport of volatile compounds, an improved understanding of quasi-saturated conditions will be beneficial for various groundwater applications, from recharge and paleoclimate studies to site characterizations and remediation strategies.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Growth of InxGa1-xAs (0.0 </= x </= 0.3) Metamorphic Pseudosubstrates on (001) GaAs Wafers and the evolution of InAs Quantum Dots on These Substrates

contributor:
Thompson, David A.
Engineering Physics

subject:
MSLs
substrates
InAs
quantum dots
QDs
symmetrical mosaicity
<110>
anisotropy
diffraction
compositional
Asymmetric tilt
heterointerfaces

abstract:
 InxGa1_xAs (0.00</= x </= 0.42) metamorphic pseudosubstrate layers (MSLs) were studied as a means to change the lattice constant of the substrates and to modify the growth conditions of InAs quantum dots (QDs) by varying the strain. The MSLs showed symmetrical mosaicity about the 110 axes but the spread was different in the two orthogonal [110] and [110] directions. The anisotropy in the mosaic spread in two < 11 O > directions was correlated to asymmetry of kinks and multilevel-terrace growth front during the growth of InxGa1_xAs buffer layers. X-ray and electron diffraction along with the least squares criterion can interchangeably be employed to determine the lattice constant of the MS Ls. It is possible to grow a defect free MSL with employing a compositional undershoot relative to the terminating buffer layer. Asymmetric tilt was found in an In0.42Ga0.58As MSL grown on a singular (001) GaAs substrate with an initial layer of a low temperature ( < 300 °C) grown InGaP prior to the growth of step-graded InxGa1-xAs (x = 0.02 to 0.42) buffer layers. The tilt around [110] axis was correlated with the imbalance of the tilt component of the Burgers vector (BV) of the 60° α-dislocations. Climb and jog formation of β-dislocations in the presence of P-interstitials were considered as a plausible mechanism for multiplication of the like-sign BV α-dislocations. These results show that an asymmetric tilt boundary can be induced in mismatched heterointerfaces grown on singular
substrates.
The evolution of InAs QDs on InxGa1-xAs(0.0</= x </= 0.3) MSLs on GaAs substrates was studied. The results indicate that the ratio of the height (h) over lateral diameter (d) of the QDs decreases with decreasing strain (i.e. the morphology of the coherent islands evolve toward a uniform film morphology
(h/d=0) with deceasing strain). This evolution is analogous to the current

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Growth and Characterization of Semiconductor Quantum Wires

contributor:
Botton, Gianluigi
Thompson, David A.
Materials Science and Engineering

subject: Semiconductor quantum wire, QWR, laser devices, long wavelength, InAs quantum wires

subject: InGaA1As, InP, variation, elastic field

abstract:
 Semiconductor quantum wire (QWR) structure is a promising candidate for potential applications in long wavelength laser devices. In this thesis, the investigations were focused on the growth and characterization on the structural and optical properties of InAs quantum wires deposited on InGaAlAs lattice matched with InP substrate by gas source molecular beam epitaxy.

 The practical growth parameters were first determined by studying the samples containing single InAs layer embedded within Ino.s3Gll{)_37Alo.10As barrier layers. These parameters were then employed for fabricating multilayer quantum wires with different (1) spacer layer thicknesses; (2) quantum wire layer thicknesses; and (3) different Al concentrations in the spacer/barrier layer materials.

Structural properties of the quantum wires were characterized by (scanning) transmission electron microscopy based techniques. The composition variation, elastic field and the variation of QWR stacking patterns in multilayer samples were qualitatively studied through diffraction contrast imaging. Quantification of the In distribution in individual QWRs and the QWR-induced In composition modulation in barrier layers were obtained by electron energy loss spectrometry and energy dispersive X-ray spectrometry, respectively. These experimentally observed structural features were explained through finite element simulations.

 The optical properties of the QWR structures were studied by photoluminescence. Optical emission at room temperature was achieved from selected multilayer QWR samples after etching and rapid thermal annealing. The emission wavelength ranging from 1.53 to 1.72 μm makes the QWR structure suitable candidates for laser device applications.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Role of Astrocytes in Fragile X Neurobiology

contributor:
Doering, L. C.
Medical Sciences

subject: FXS, fragile X Syndrome, Fragile X mental retardation 1, FMR1, gene, FMRP, astrocytes, nervous system, immunocytochemistry, morphometric, synaptic protein analyses

abstract:
 Fragile X Syndrome (FXS) is the most common inherited disease of mental impairment, typically caused by a mutation in the Fragile X mental retardation 1 (FMRJ) gene. The clinical features are thought to result from abnormal neurobiology due to a lack of the Fragile X mental retardation protein (FMRP). Previously, it was thought that FMRP was confined exclusively to neurons; however, our laboratory recently discovered that astrocytes also express FMRP. Consequently, it is possible that astrocytes also suffer abnormalities as a result of a lack of FMRP. Astrocytes play integral roles in the development and maintenance of communication in the central nervous system. Therefore, it is now important to determine the contribution of astrocytes to the abnormal neuronal phenotype seen in FXS. In these experiments, neurons and astrocytes were
independently isolated from wild type (WT) or FMRJ null mice and grown in a coculture. Neurons were evaluated using immunocytochemistry in combination with computer-aided morphometric and synaptic protein analyses. The findings presented here provide convincing evidence that Fragile X astrocytes contribute to the abnormal neurobiology seen in FXS . Fragile X astrocytes alter the dendrite morphology and excitatory synaptic protein expression of WT neurons in culture; and, importantly, when Fragile X neurons are grown with WT astrocytes these changes are prevented. Interestingly, the Fragile X astrocytes appear to act by causing a delay in development; even WT neurons grown in the presence of Fragile X astrocytes, that displayed an abnormal phenotype at 7 days in culture, exhibited nearly normal dendrite morphology and expression of excitatory synapses at 21 days. Furthermore, the results suggest that the dendritic abnormalities induced by the Fragile X astrocytes specifically target neurons with a spiny stellate morphology. This research establishes a role for astrocytes in the development of the abnormal neurobiology seen in FXS, and as such, the results presented here have significant implications for Fragile X research. The novel prospect that astrocytes are key contributing components in the development of FXS provides an exciting new direction for investigations into the mechanisms underlying FXS, with many unexplored avenues for potential treatment strategies.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Helminth Therapy in a Murine Model of Chemically Induced Colitis

contributor:
McKay, Derek M.
Medical Sciences

subject: helminth, therapy, murine model, colitis, disease,

abstract:
 Helminth parasite infection induces a strong immune response in the host aimed at destroying the parasite and reducing any associated inflammation. In humans and rodents, this response is dominated by the Th2 cytokines and involves the activation of mast cells, B cells and eosinophils, as well as increased production of lgE. There is evidence from both murine and human studies that the helminth-induced anti-inflammatory response is also capable of protecting the host from co-existing autoimmune disease, including asthma, allergies and colitis. My hypothesis is that infection with the parasitic helminth H. diminuta can treat and/or prevent the symptoms of Th1-dominated inflammation. This anti-colitic effect is dependent on IL-10 and involves the recruitment of the alternatively activated macrophages.

 Using the dinitrobenzene sulfonic acid (DNBS) model of colitis, I examined the ability of the rat tapeworm, Hymenolepis diminuta, to reduce inflammation in a non-permissive mouse host. H. diminuta was chosen as the ideal candidate for treating intestinal disease because it is non-invasive, does not have hooks or teeth which can damage the host, and can be easily maintained in the laboratory and controlled during experimental infection. Mice that received DNBS alone developed colitis within 72 hours. Mice that had been previously infected with five H. diminuta larvae were significantly protected from the colitis, as measured by reduced clinical disease and histological damage scores as well as reduced levels of myeloperoxidase (MPO) from colonic tissue samples. It was also determined that the anticolitic effect was dependent on a viable parasite infection. Infection with H. diminuta induced an increase in colonic IL-10 mRNA and IL-10 secretion by stimulated splenocytes - when IL-10 was blocked by administration of an anti-IL-10 antibody, the anticolitic effect of H. diminuta infection was reduced. H. diminuta infection also induced increased expression of the alternatively activated macrophage (AAM) markers arginase 1 and FIZZ1. Treatment with in vitro-derived AAMs reduced the symptoms of DNBS-colitis.

 The effect of H. diminuta infection on oxazolone colitis, a chemically induced colitis characterized by increases in IL-4 and IL-13, was also examined. Infection with H. diminuta induced a significant increase in inflammation and inhibited recovery from oxazolone-colitis. Increases in IL-5 and eosinophils were also observed. Further examination revealed that increased IL-5, induced by administration of an adenovirus carrying the IL-5 gene, had a deleterious impact on the oxazolone colitis, exacerbating inflammation and increasing eosinophilia.

 While the idea of helminth therapy may be unappealing, there is increasing interest in the use of helminth parasites for the treatment of inflammatory disease. There is some concern, however, that the Th2 response induced by H. diminuta infection could exacerbate some disorders involving increases in the Th2 cytokines. Thus, while this therapy may be beneficial for most, careful characterization of the immunological basis of any pre-existing disorders would be necessary in order to avoid any harmful side-effects.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: SHROOM3 IN THE KIDNEY

title: SHROOM3 PLAYS A ROLE IN PODOCYTE CYTOARCHITECTURE

contributor:
Bridgewater, Darren
Medical Sciences

subject:
Kidney
Glomerulus
Podocyte
Shroom3
CKD
Kidney Development

abstract:
Chronic kidney disease (CKD), defined as an irreversible reduction in glomerular filtration rate, is a large public health concern. Dissecting the genetic components of CKD is required to improve our understanding of disease pathogenesis. Researchers have identified that SHROOM3, has very high associations with kidney disease and function. Shroom3 encodes an actin-binding protein important in regulating cell and tissue morphogenesis. However, there is a lack of evidence supporting a role for Shroom3 in kidney function or disease. Here, I investigated the developmental and functional role of Shroom3 in the mammalian kidney. For the first time, I described the expression pattern of Shroom3 in the embryonic and adult mouse kidneys. By performing in situ hybridization and immunohistochemistry, I demonstrated that Shroom3 is expressed in the condensing mesenchyme, podocytes, and collecting ducts. I further showed that Shroom3 protein is localized in the foot processes of podocytes, utilizing immunogold labeling and transmission electron microscopy. In order to uncover a potential role of Shroom3 in the kidney, we utilized Shroom3 knockout mice. Shroom3 mutants demonstrated marked glomerular abnormalities including cystic and degenerating glomeruli, and reduced glomerular number. Scanning and transmission electron microscopic analyses of Shroom3 mutant glomeruli revealed disruptions in podocyte morphology characterized by disorganized foot processes with less interdigitation and segmental foot processes effacement. Furthermore, immunofluorescence analysis of mutant kidneys revealed aberrant distribution of podocyte actin-associated proteins. Elucidating the underlying molecular mechanism of this abnormal podocyte architecture;
v
we demonstrated that in the absence of Shroom3, Rho kinase is mislocalized in the apical membrane of podocytes. As a result, mislocalized Rho kinase failed to phosphorylate non-muscle myosin and induce actomyosin contraction resulting in a patchy granular distribution of actin in the podocytes of Shroom3 mutants. Taken together, our findings established that Shroom3 is essential for proper actin organization in the podocytes through interaction with Rock. Furthermore, we took advantage of a haploinsufficiency phenotype of Shroom3 heterozygote adult mice and demonstrated these mice develop glomerulosclerosis and proteinuria. In conclusion, our studies provided evidence to support a role for Shroom3 in kidney development and disease and support the GWAS studies that suggested a correlation between SHROOM3 variants and kidney function in humans.

abstract: Thesis

abstract: Master of Science (MSc)


title: Molecular Mechanism(s) of Sex Differences in Lipid Metabolism in Human Skeletal Muscle

contributor:
Tarnopolsky, Mark A.
Medical Sciences

subject: differences, molecular, mechanisms, lipid, metabolism, muscle

abstract:
 It is well understood that compared with men, women are better able to withstand starvation, have better ultra-endurance capacity, oxidize more fat during endurance exercise, and are more resistant to fat oxidation defects i.e. diet-induced insulin resistance. However, the mechanism(s) for the observed sex differences are unknown. It was my hypothesis that women have greater fat oxidation capacity in skeletal muscle than men.

 The objectives of my thesis were to determine the mechanism(s) by which women oxidize more lipids; including the role of estrogen as a possible regulator. The most significant findings were that: 1) mRNA for fatty acid oxidation genes are higher in women compared with men, which was confirmed by Stringent Affymetrix GeneChip array analysis, combined with RT-PCR (chapter 2); 2) long-chain acyl-CoA dehydrogenase in human skeletal muscle is not quantifiable despite the majority (90%) of fatty acids oxidized during exercise are long-chain fatty acids (chapter 3); 3) β-oxidation enzymes: tri-functional protein alpha, very long chain acyl-CoA dehydrogenase, and medium chain acyl-CoA dehydrogenase are significantly higher in women compared with men (chapter 4); 4) Acute (8 days) 17β-estradiol supplementation in men significantly increased protein content of β-oxidation enzymes in skeletal muscle, possibly through the regulation of PGC-1α and microRNA (chapter 5).

 In conclusion, my data provided novel insights into the enhanced ability of women to oxidize fat under periods of metabolic stress by showing that: 1) women are transcriptionally (mRNA) "primed" for known physiological differences in metabolism; 2) women have more protein content of the major enzymes involved in long and medium chain fatty acid oxidation; 3) E2 partially regulates lipid metabolism in skeletal muscle by pre-translational modifications of factors involved in β-oxidation. These findings contribute to the molecular understanding of sex differences in substrate utilization.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Calorimetric Investigation of Recrystallization in Al-Mg-Si-Cu Alloys

contributor:
Malakhov, Dmitri
Materials Science and Engineering

subject: recrystallization behavior, calorimetry, non-isothermal annealing conditions, deformation, precipitation, DSC, JMAK, kinetics

abstract:
 The recrystallization behavior of three Al-Mg-Si-Cu alloys with varying iron and manganese additions was studied by differential power scanning calorimetry under nonisothermal annealing conditions. The influence of cold deformation on the precipitation sequence and its interaction with recrystallization was also investigated. The DSC experiments were complemented by hardness measurements and microstructural studies by optical and electron microscopy. The DSC signals, after optimization of the baseline, were used for the calculation of the kinetic parameters of the recrystallization process. Two different modeling approaches based on global JMAK kinetics were implemented. The first approach utilizes the classical isothermal JMAK expression directly, while the second approach introduces a path variable related to the thermal history of the material in the JMAK description. Model-independent estimates of the activation energy were also evaluated using the Flynn-Wall-Ozawa integral isoconversion method.

 The results show that the initial stages of recrystallization are not affected by the preceding precipitation processes and recrystallization always follows the precipitation of the Q' phase. However, during recrystallization enhanced coarsening of the Q' phase
takes place leading to its transformation to the more stable Q phase. The Q phase exerts a Zener pinning pressures on the migrating boundaries preventing the formation of an equilibrium grain structure. Moreover, for high Fe and Mn additions, discontinuous precipitation of Mg2Si overlaps with the end of recrystallization and exerts an additional pinning pressure on the boundaries. Varying the Fe and Mn content significantly affects the recrystallization kinetics. PSN is promoted in alloys with the higher Fe and Mn content and the recrystallization temperature shifts to lower values. The modeling results show that the recrystallization process conforms to the classical JMAK type behavior. The course of the reaction was reproduced successfully by the path variable approach and the evaluated activation energies were in good agreement with the isoconversional model-independent estimates. However, when the classical JMAK expression was applied directly to non-isothermal measurements, a dependency of the recrystallization process on thermal history was observed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Familiarity Modifies Early Perceptual Face Processing as Revealed By Event-Related Potentials

contributor:
Shedden, Judith M.
Psychology

subject: social, relationships, event-related, familiarity, perceptual, face

abstract:
 Accurate face recognition plays a critical role in developing and maintaining social relationships. Typically developing adults show expertise when processing faces, demonstrated by their ability to recognize new faces even after a single exposure. Furthermore, face recognition is superior for highly familiar faces associated with rich semantic information. Although semantic processes mediate familiar face recognition, it is unclear what processes mediate unfamiliar face recognition. The main objective of my thesis was to identify unique neural mechanisms underlying familiar versus unfamiliar face recognition and to detail how these mechanisms change as a result of learning. I used event-related potentials (ERPs) to assess the stages of face processing affected by familiarity.

 In Chapter 1, I reviewed the literature contrasting familiar and unfamiliar face recognition processes from cognitive and neural perspectives.

 In Chapter 2, I identified processes involved in unfamiliar face recognition by
recording ERPs to repeated presentations of unfamiliar faces in upright and inverted orientations. Inverted faces portray the same structural information as upright faces but with novel orientation that disrupts identity processing. Repeated exposure to an upright face (and not an inverted face) produced repetition priming at an early perceptual stage reflected by the N170 component, suggesting that unfamiliar face recognition is mediated by early perceptual representation.

 In Chapter 3, I directly tested whether semantic information modifies early
perceptual face processing. I recorded ERPs to new faces that were learned over a five-day session with either person-specific or irrelevant information. N170 repetition priming was observed for all faces except those learned with person-specific information, suggesting that relevant semantic information, and not merely perceptual experience, changes early perceptual face processing.

 In Chapter 4, I assessed the relationship between N170 and N400 recognition processes. Specifically, I examined whether top-down semantic processes reflected by the N400 modulate early identity processes reflected by the N170. I constructed composite faces by combining facial features from different famous individuals; the facial features conveyed incongruous identity information so that when the face was processed as a whole it was perceived to be novel. Both familiar faces and composite faces failed to elicit N170 repetition priming but did elicit a similar N400 response, suggesting that familiar face recognition can be achieved with very little facial information. Moreover, these results suggest that the retrieval of semantically relevant information during familiar face recognition occurs even in the presence of incongruous perceptual information and that such processing modulates early perceptual processes.

 Together, these results demonstrate the interplay between memory and perception (which I summarize and discuss in Chapter 5), revealing different mechanisms of face recognition as a function of person-specific information. Unfamiliar face recognition takes place at the perceptual stage reflected by the N170 and is revealed through repetition priming. As an unfamiliar face becomes well known, its recognition processes shift to a later semantic stage reflected by the N400 and such semantic processes seem to modulate early perceptual processes. This knowledge has advanced our understanding of face processing at cognitive and neural levels.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Influence of Adult Males, Dietary Phytoestrogens, and an Index of In Utero Androgen Exposure on Sexual Development In The Female Mouse (Mus Musculus)

title: Males, Diet, Prenatal Androgens and Female Sexual Maturity

contributor:
deCatanzaro, Denys
Psychology

subject: female, male, sexual maturity, maturity, maturation, Mus Musculus, dietary phytoestrogens, prenatal androgens, puberty, male-induced, fertility, urinary creatinine, 17β-estradiol, progesterone, uterine, ovarian tissue, testosterone

abstract:
 The age at which a juvenile female reaches sexual maturity can be modulated by a variety of environmental and social factors. Experiments described in this thesis were designed to enhance the current understanding of the relationships among three variables that influence the onset of sexual maturation in female mice (Mus musculus), including: [1] exposure to dietary phytoestrogens during development, [2] variations in prenatal androgens, and [3] the presence or absence of genetically-unrelated males after weaning. For the first time, age at onset of male-induced female puberty was investigated using non-invasive behavioural and fertility measures. Through enzyme immunoassay procedures, daily output of urinary creatinine, 17P-estradiol, and progesterone was profiled in developing females that were either isolated or exposed to adult males. Uterine and ovarian tissue was also measured in such females, and male exposure was observed to increase reproductive tissue mass and was influenced by prior androgen exposure in interaction with diet and male presence. Male-exposed females fed a diet containing phytoestrogens immediately became sexually receptive when housed directly with males, and they conceived earlier than females in other conditions. Females with longer anogenital distance, which reflects higher in utero androgen exposure, displayed more escape attempts and aggressive posturing in the direct presence of males, especially when they had been housed near males and fed the phytoestrogen-containing diet. Urinary 17P-estradiol was substantially reduced in females raised on the phytoestrogenfree diet. Urinary output of progesterone was not strongly influenced by diet. Maleexposed females ' output of progesterone and 17P-estradiol was more dynamic in comparison to that of isolated females. The size of this effect depended on diet, prior androgen exposure, and whether urinary steroid measures were adjusted by urinary creatinine. Urinary creatinine was elevated by the low phytoestrogen diet and reduced by male exposure. These data suggest that dietary phytoestrogens and in utero androgen exposure interact with presence or absence of males in determining the age at onset of sexual maturity in developing females.

 A final experiment was designed to examine two components of adult male urine, preputial gland emissions and unconjugated estrogens, that have been posited to act on females to advance reproductive maturation. Intact and preputialectomized males were compared in their output of urinary creatinine, 17~-estradiol, and testosterone, and in their influence on reproductive tissue in juvenile females. Lack of preputial glands did not hinder the capacity of males to induce uterine and ovarian growth in females. Male urinary creatinine was reduced by exposure to juvenile females. Creatinine-adjusted 17~estradiol and testosterone were greater in female-exposed males, regardless of whether the preputial glands were present. Based on these findings and those reported elsewhere, it is probable that male excreted urinary steroids are important in regulating reproductive changes in developing females exposed to males.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)