title: DESIGNING INJECTABLE POLY(OLIGO ETHYLENE GLYCOL METHACRYLATE)-BASED HYDROGELS FOR DRUG DELIVERY AND TISSUE ENGINEERING APPLICATIONS

contributor:
Hoare, Dr. Todd R.
Chemical Engineering

abstract:
Injectable hydrogels are 3D water swollen polymeric networks formed through in situ gelling mechanisms. The minimally invasive nature of their delivery into the body, coupled with their highly tunable chemical properties, offer broad promise in mimicking or stimulating native tissue functions, essential to effectively treat organ failures resulting from injuries, aging, and disease.  Alternately, injectable hydrogels can act as depot-based drug delivery vehicles for various therapeutics including drugs or cells that can be injected directly at a desired site of action for long-term efficacy. While such hydrogels can be formed from a variety of materials (both natural and synthetic) and through a variety of in situ crosslinking mechanisms (both physical and covalent), combining the chemical flexibility of synthetic polymers with reversible covalent gelation in which gel degradation can be better programmed according to its environment offers an attractive combination of properties to rationally engineer in situ gelling hydrogels for a variety of applications.
    This thesis presents the development of degradable, thermoresponsive and injectable hydrogels based on poly(oligo ethylene glycol methacrylate) (POEGMA), using the rapid covalent cross-linking of hydrazide and aldehyde functionalized POEGMA precursors to form a hydrazone bond capable of undergoing hydrolytic degradation at physiological pH/temperature. First, a new method to make synthetic and degradable hydrogels based on POEGMA is presented, demonstrating that POEGMA in situ-gelling systems can offer the advantageous biological interactions of current state-of-the-art poly (ethylene glycol) (PEG) hydrogels while also offering superior flexibility to control gel properties. The thesis then proceeds to show the facile modulation of POEGMA hydrogel volume phase transition temperatures (VPTT) through varying the length of the ethylene oxide side chains of the OEGMA monomers used during copolymerization. A thermoresponsive gel (similar to the conventional poly(N-isopropylacrylamide) networks) can be achieved while maintaining the excellent stealth like properties in vitro and in vivo of PEG hydrogels. By mixing POEGMA precursor polymers with different phase transition temperatures together, hydrogels with additive properties and the potential for the rational formation of internal microdomains are generated, domains that can be leveraged to control the kinetics of protein release.  Next, the microscopic and macroscopic effects of incorporating the charged moieties N,N-dimethylamino ethyl methacrylate (DMAEMA) and acrylic acid (AA) into the POEGMA backbone are explored.  We identify both the potential for secondary network formation that enhances gel mechanics as well as the potential to modulate cell responses with the hydrogels as a function of charge type and density, including the application of these charged hydrogels as injectable delivery vehicles for human retinal epithelial cells.  Finally, mixed natural-synthetic hydrogels were reported by the incorporation of natural polymer dextran (DEX) into the POEGMA hydrogel platform.  We show the resulting hydrogels offer the benefits of both POEGMA (low non-specific adsorption, thermoresponsivity) and dextran (cell interactions and enzymatic degradability), facilitating the generation of hydrogels with desirable in vivo properties.  Based on the demonstrated capacity throughout this thesis to rationally change the properties of in situ-gelling hydrogels (often independent of other properties), this research has significant implications for the improvement of hydrogel materials for drug delivery and tissue engineering.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Injectable hydrogels are 3D water swollen gel networks formed by simple mixing of water-soluble polymers. Such hydrogels have the potential to mimic or stimulate native tissue functions and thus hold enormous promise in treating organ failures resulting from injuries, aging, and disease. Injectable hydrogels can also act as vehicles for various therapeutics including drugs or cells, and they can be administered minimally invasively. They can be formed from a variety of materials of natural and synthetic origins and through rapid physical or chemical crosslinking mechanisms. This thesis presents the development of degradable, thermoresponsive and injectable hydrogels using poly(oligo ethylene glycol methacrylate) (POEGMA). We demonstrate that by modifying the chemistry of POEGMA as well as how it is combined with other materials (e.g. charged functional groups or natural polymers like dextran) can significantly change the swelling, degradation, mechanical, protein interaction, cell interaction, and in vivo tissue response properties of the hydrogels, allowing them to be customized for various applications in drug delivery, cell delivery, or tissue engineering to improve efficacy relative to current materials.


title: DEPHOSPHORIZATION KINETICS FOR REACTION OF BLOATED METAL DROPLETS WITH OXIDIZING SLAG

contributor:
Coley, Kenneth
Materials Science and Engineering

abstract:
Dephosphorization is one of the most important refining reactions in Steelmaking in the Basic Oxygen Furace (BOF). Dephosphorization can only occur by reaction between the metal and the slag and is linked in a rather complex way to the decarburization of droplets in the gas-slag-metal emulsion zone. Decarburization affects dephosphorization of metal droplets by influencing the following: residence time, driving force and mass transfer of phosphorus. Residence time is the contact time of metal droplets with slag, which is determined based on the bloating behavior of metal droplets. This particular aspect of dephosphorization has been studied recently by researchers in the author’s laboratory and others. Therefore, the influence of decarburization on driving force for dephosphorization and mass transfer of phosphorus in the metal phase was the main focus of this study.
The effect of decarburization on driving force for dephosphorization was studied in detail by varying decarburization rates which are a function of metal sulfur content, and determining the dynamic interfacial oxygen potential. The dephosphorization driving force was found to have a strong inverse relationship with increasing decarburization rate because the associated oxygen consumption decreases the interfacial oxygen potential. The decreased driving force further affected dephosphorization kinetics by shifting the rate controlling step, to include a greater influence of mass transport in the slag. This observation showed a good agreement with other work on dephosphorization kinetics in the published literature.
The dynamic interfacial oxygen potential, controls dephosphorization driving force, between an iron carbon alloy and oxidizing slag was calculated based on a mathematical model, which combines measured decarburization rates with mass transfer of FeO in the slag. With this model, the mass transfer coefficient of “FeO” in slag, k_FeO, was firstly determined as a function of the fraction of liquid slag and total iron oxide in the slag. The influence of dynamic interfacial oxygen potential on dephosphorization kinetics was sequentially analyzed by determining the time dependent interfacial phosphorus partition ratio. The agreement with literature observations confirmed the reliability of the interfacial oxygen potential model developed in this study.
Comparing the experimentally observed dephosphorization behaviour of carbon containing droplets with that of carbon free droplets, mass transfer coefficient for phosphorus in the metal for carbon containing droplets was found to be two orders of magnitude higher than that for carbon free droplets because of the stirring effect provided by CO gas generation inside the metal droplet. By combining a theoretical analysis of CO bubble nucleation kinetics with surface renewal theory, the predicted mass transfer coefficient of phosphorus in the metal phase was in good agreement with experimentally measured results. Extension of this analysis to results from a number of published studies on dephosphorization, showed an excellent qualitative agreement with experimental observations, i.e., the effect of silicon in the metal and the effect of iron oxide in the slag. The combined effect of silicon and temperature also showed agreement but the effect of temperature for silicon free metal was not fully explained.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Synthesis and Application Development of Oxygen (O2) and  Carbon Dioxide (CO2) Switchable Polymer

contributor:
Shiping, Zhu
Chemical Engineering

subject:
Switchable polymers
Oxygen
Carbon Dioxide

abstract:
Stimuli-responsive polymers have attracted great attention due to their unique responses in physicochemical properties to changes in external environment and stimuli variations (e.g. pH, thermo, light, electric and magnetic field, etc.). Introduction of gas triggers has greatly expanded the family of stimuli-responsive polymers since the first work on a CO2-switchable polymer was reported in 2006. Although significant progresses have been achieved over the past decade, studies on gas-switchable polymers are still at an early stage, with many challenges in both fundamental and application areas remaining to be tackled.

This thesis focuses on synthesis and application development of O2 and CO2 switchable polymers. The thesis starts from investigating O2-switchable thermo-responsive fluorinated monomers and their linear random copolymers, which undergo LCST shifting induced by O2 treatment. It provides good insight and general guidance for design and screening of monomer candidates for the synthesis of O2-switchable polymers. The second part of the thesis presents development of the first O2 and CO2 dual gas-switchable microgel system and building of the microgel-colloidosomes with O2 and CO2 tailored shell permeability. The latter is evaluated as microcapsules for hierarchical control-release of water-soluble cargo molecules upon respective O2 and CO2 treatment. The last part of the thesis explores preparation of various porous polymer systems from high internal phase emulsion (HIPE) templates. In particular, a highly porous polyHIPE membrane with "open-cell" structure exhibiting CO2-switchable surface wettability is promising for smart separation applications. This thesis represents a significant progress and a solid step forward in the development of gas-switchable polymers from monomer design, polymer preparation, and advanced application of polymer systems.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Polymer materials are used in every aspect of our daily life, from clothing, furniture to construction. This thesis work is to develop functional polymers that can feel variations in environment (e.g. pH, thermo, light, magnetic, etc) and give out changes in properties. Such materials are smart for stimuli-responsive applications. The first report of carbon dioxide (CO2)-switchable polymers in 2006 was marked as the start of gas-responsive polymers. Gas triggers interact with specific functionalities in polymer chains and change their physicochemical properties such as chain structure, architecture, hydrophilicity and polarity. Oxygen (O2) and CO2 are explored in this work to reversibly trigger changes in volume, shell permeability and surface wettability, of different polymer systems. Potential applications include drug control-release, smart oil/water separation, and so on. This work presents a systematic study on the development of O2 and/or CO2-switchable polymers from monomer design, polymer preparation, and advanced application of polymer systems. It represents a significant progress and a solid step forward in the study of gas-switchable polymers.


title: MATERIALS AND INTERFACE ENGINEERING FOR SOLUTION-PROCESSED UV LIGHT RESPONSIVE ORGANIC PHOTOTRANSISTORS

contributor:
Zhu, Shiping
Chemical Engineering

subject:
Organic phototranistors
Organic thin film tranistors
Organic semiconductor
Polymers
UV response

abstract:
Organic electronics have reached the level of commercialization and are important parts of our daily life. They are integrated into portable computers, cell phones, identification cards, television, cars, etc. The organic thin film transistors (OTFTs) are the most attractive organic electronic elements that have applications as electronic flexible paper, sensors, smart cards, erasable memory devices, RF-ID tags, and in backplanes for OLED displays. Their performance has already exceeded the performance of transistors based on the amorphous silicon (α-Si).

Organic thin film phototransistors (OPTs) have attracted significant research attention as functional OTFTs due to the unique structure of OTFTs (three-terminal device) complemented with the light (fourth terminal). The OTFTs structure enables modulation and amplification of the output signal (the drain current) while light gives the functionality and enhances the performance. Compared to organic photodiodes, OPTs have higher sensitivity and lower noise due to the OTFT structure. Additionally, the advantage of OPTs over inorganic PTs lays in a variety of light responsive organic materials that can be used as active channel materials. Accordingly, use of organic compounds enabled OPTs fabrication from solution, melt, and printing, over large areas of plastic substrates with which they are compatible. So far, many researchers have reported high-performance OPTs. Typically, synthesis of the new light receiving/emitting semiconducting materials is the common approach for the OPT development. Another way is to engineer the device structure by introducing new layers with different functionalities. Often, synthesis is costly, complex, lengthy, and not industrially feasible.

This thesis focuses on the development of new methods and materials for OPT performance enhancement to avoid lengthy synthesis and fabrication processes. According to the layers in a typical OPT, that is, from the top to the bottom: active channel, channel/gate dielectric interface, and the gate dielectric layer, the thesis has three major focuses: engineering of the active channel for high-performance OPTs using existing small molecule and existing or new dielectric polymeric materials (Chapters 3-5), interface engineering (Chapter 6), and engineering of the gate dielectric layer (Chapter 7). Utilizing blends of a UV-A responsive 2,7-dipentyl[1]benzothieno[3,2-b][1]benzothiophene (C5-BTBT) small molecule semiconductor and various dielectric polymers (polyesters, PMMA, PVAc, PS, and PC) we developed highly photoresponsive and photosensitive OPTs. Furthermore, we designed and synthesized a new polyimide that is soluble, thermally stable, with reduced deep coloration and more importantly with the strong electron withdrawing groups. High-performance and highly photosensitive OPTs were achieved with capabilities of the application as photo memory elements characteristic of fast switching and long retention times of the persistent photocurrent. We demonstrated that by simple channel/dielectric interface modification using organosilanes with different end groups, the drain photocurrent, and hole mobility could be modulated and enhanced under the UV light illumination. In the final part, we demonstrated that both active channel and dielectric layer engineering could synergistically enhance the performance of OPTs for potential fabrication as photo memory elements. This thesis contributed significantly to fundamental knowledge of photoresponsive organic electronic devices and application of OPTs in the area of printed and flexible electronics

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Organic electronics have become a part of our daily life since they are integrated into cell phones, computers, TVs, displays, etc. Their advantage is their versatility due to a variety of organic compounds that can be used as semiconductors for the specific applications, low-cost processing methods (solution, printing, and melt) and large-area flexible substrates that can be used for their fabrication. For the same reasons, organic phototransistors are very attractive for modern optoelectronics. Generally, in this study, we developed and demonstrated new strategies of developing an organic phototransistor and enhancing/optimizing its performance. Firstly, we developed semiconducting blends that are responsive to UV-A light when integrated into an organic phototransistor. Secondly, by channel/gate dielectric interface manipulation we demonstrated control over photoelectrical properties of the organic phototransistor and discovered mechanisms of the enhancement. Thirdly, we optimized and developed reliable, high-performance, and highly UV responsive organic phototransistors with potential application as a photo memory element


title: MECHANORESPONSIVE POLYMERS BASED ON SPIROPYRAN MECHANOPHORE

subject:
spiropyran
mechanophore
smart polymer
force-senstive

abstract:
Spiropyran (SP) is an effective mechanophore because it is easy to be covalently incorporated into polymers and capable of changing color upon mechanical loading. SP motif is a model mechanophore in fundamental studies of mechanochemistry. Therefore, it is of great significance to gain a deep and comprehensive knowledge of SP mechanochemistry for the exploration of mechanochemistry in general. In the beginning of this thesis, a review of SP mechanophore was presented from an engineering perspective. A workflow for SP mechanochemistry, applications in various polymeric systems, impacting factors and characterization techniques as well as conclusions were thoroughly presented. The review aimed to offer deep insight into polymer mechanochemistry and provide approaches to study other mechanophores using the example of SP mechanochemistry in polymers.

So far there have been three types of SP mechanophores (SP1, SP2 and SP3) reported in the literature. SP1 and SP2 are sensitive to both UV light and mechanical force, whereas SP3 is sensitive to mechanical force but not to UV, which is an excellent candidate for outdoor applications. Due to the unique feature of SP3, this project is mainly focused on applying SP3 mechanophore into functional and structural polymeric materials.
•	We designed and synthesized divinyl SP3 mechanophore cross-linker, which can be employed in chain growth polymerization, accounting for more than 80% of total polymer products. As a demonstration, SP3 was incorporated as a cross-linker in the free radical polymerization of methyl acrylate (MA). The mechanoactivation and UV activation of SP3-cross-linked PMA were investigated in details.
•	SP3 mechanophore cross-linker was covalently incorporated into two widely used polyolefins through facile cross-linking. It represents the first example of smart polyolefins that feel the force by color changing, opening the possibilities of applying SP mechanophore into widely used polyolefin materials, accounting for more than half of the total polymer materials.
•	We prepared force sensitive acrylic latex coating via covalent incorporation of SP3 mechanophore cross-linker. It is the first example of mechanochromic acrylic latexes, and it provides insight into the design of force-sensitive and self-reporting polymer coatings.
•	We reported the CO2-breathing induced reversible activation of SP3 mechanophore within microgels. This work provides an effective approach to study the forces inside swollen microgels. It also demonstrates the biomimetic processes with shape deformation and concomitant color/fluorescence change.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Smart polymer has been a research focus for recent decades. One of the most critical responses is to monitor mechanical failures of structural materials, such as stress fraction, fatigue and hysteresis within the polymer by giving off early warnings to prevent the catastrophic failure from occurring. The most prevalent approaches to design a mechanoresponsive polymer is to incorporate a “mechanophore”, containing mechanically labile bonds that are subjective to change under exogenous forces. Spiropyrans (SP) are great candidates for stress/strain sensing in terms of mechanochromism. When mechanical force is applied onto Cspiro-O bond, SP undergoes reversible 6-π ring opening reaction to yield merocyanine (MC). The ring-closed form SP is colorless or yellow and nonfluorescent, whereas the ring-open form MC is purple or blue or red and fluorescent. In this project we first designed and synthesized divinyl spiropyran cross-linker, fitting for chain growth polymerization, which accounts for more than 80% of polymer products. Then the divinyl spiropyran cross-linker was covalently incorporated into polymethylacrylate, polyolefins, acrylic latex coating and CO2-breathing microgels, aiming to broaden the potential applications of mechanophore into various polymers. We also summarized the recent development and studies of spiropyran mechanophore into a comprehensive review from an engineering prospective to provide insights into polymer mechanochemistry and study approaches for other mechanophores.


title: Advancing Financial Market Volatility Measurement and Forecasting

contributor:
Maheu, John
Business

abstract:
This thesis proposes several new and useful financial econometric tools to facilitate risk analysis, portfolio choice and forecasting.

This thesis starts with an introduction in Chapter 1. The research background, motivation and the structure of the thesis are illustrated in this chapter.

Chapter 2 proposes a class of models that jointly model returns and ex-post variance measures under a Markov switching framework. Both univariate and multivariate return versions of the model are introduced. Estimation can be conducted under a fixed dimension state space or an infinite one. The proposed models can be seen as nonlinear common factor models subject to Markov switching and are able to exploit the information content in both returns and ex-post volatility measures. Applications to equity returns compare the proposed models to existing alternatives. The empirical results show that the joint models improve density forecasts for returns and point predictions of return variance. Using the information in ex-post volatility measures can increase the precision of parameter estimates, sharpen the inference on the latent state variable and improve portfolio decisions.

Chapter 3 offers a new exact finite sample approach to estimating ex-post variance using Bayesian nonparametric methods. Until now ex-post variance estimation has been based on infill asymptotic assumptions that exploit high-frequency data. In contrast to the classical counterpart, the proposed method exploits pooling over high frequency observations with similar variances. Bayesian nonparametric variance estimators under no noise, heteroskedastic and serially correlated microstructure noise are introduced and discussed. Monte Carlo simulation results show that the proposed approach can increase the accuracy of variance estimation. Applications to equity data and comparison with realized variance and realized kernel estimators are included.

Chapter 4 extends the third chapter to estimate the ex-post covariance matrix of asset returns from high-frequency data. As before, pooling is used to improve estimation accuracy and the method does not rely on infill asymptotic assumptions. In addition, the proposed covariance estimator is guaranteed to be positive definite. Furthermore, a new synchronization method of observations based on data augmentation is introduced. The Bayesian estimator is made robust to independent microstructure noise and nonsynchronous trading. According to Monte Carlo simulations, the new estimator is very competitive with existing estimators. Empirical applications evaluate the new estimator from an economic perspective.

Finally, Chapter 5 concludes and summarizes the contribution of this thesis to the literature.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Development of a Near-Field Microwave Imaging System

contributor:
Nikolova, Natalia
Bandler, John
Electrical and Computer Engineering

abstract:
This thesis presents the results of an ongoing development of a near-field microwave imaging system. The thesis mainly focuses on the image reconstruction algorithms and data processing. Two linear-inversion methods, block circulant with circulant blocks (BCCB) scattered-power mapping (SPM) and convolution-based SPM, have been proposed. Both methods are general and efficient in solving the linear inverse problem. The images are reconstructed in quasi-real time with the BCCB SPM and in real time with the convolution-based SPM. A new method of building the SPM system matrix formed by the calibration object power maps is proposed. It allows for a reduced number of calibration measurements. BCCB SPM and convolution-based SPM are intended as a tool to solve weak-scattering problems or as a linear-inversion module within nonlinear iterative reconstruction.
An algorithm has been developed for the de-noising of S-parameter data used in microwave imaging. It enables the efficient estimation of the noise-free signal component and its separation from the noise component in 2D-scan data sets. The proposed algorithm offers several benefits in imaging. First, it can suppress noise and uncertainties in the data used as input to the reconstruction algorithms. Such noise and uncertainties lead to image artifacts and errors. Second, the condition number of the BCCB system matrix improves as a result of the de-noising preprocessing of the raw data. The algorithm can also be used to quantify the imaging system’s dynamic range. Finally, it allows estimating the signal-to-noise ratio of a particular data set.
Another development is concerned with a novel calibration strategy for near-field quantitative linear-inversion methods. It employs a metallic scattering probe embedded in the background. The biggest advantage of the calibration with metallic scattering probe is the target-independent quantitative accuracy. Also, full polarimetric information about the incident field can be readily obtained.
An axial-null illumination has also been proposed to simplify the calibration of microwave imaging systems. Such illumination also enhances the spatial resolution. It can be achieved with various array configurations but a minimum of two transmitting antennas are required. Due to the intrinsic antisymmetry of the axial-null illumination, the baseline signals are suppressed down to the noise level of the measurement system. Therefore, the most important advantage of the proposed imaging setup is that it eliminates the need for background (or baseline) measurements. The discussed improvements are expected to occur for any imaging technique that exploits wave-like physical fields.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Effect of Chemical Pressure on the Magnetic Ground States of Rare Earth Pyrochlores

title: Application of Chemical Pressure to Rare Earth Pyrochlores

contributor:
Luke, Graeme M.
Physics and Astronomy

subject:
Magnetism
Pyrochlore
Frustration
Chemical Pressure
Neutron Scattering
Muon Spin Relaxation
High Pressure Synthesis

abstract: The rare earth pyrochlore oxides, with formula R2B2O7, are a chemically versatile family of materials that exhibit a diverse array of magnetic phenomena. In this structure the R and B site cations each form a corner-sharing tetrahedral network, a motif that is prone to intense geometric magnetic frustration. As a consequence of their magnetic frustration, rare earth pyrochlores are observed to host a number of remarkable states such as spin ice and spin liquid states. In this thesis we endeavor to explore the phase diagrams of the rare earth pyrochlores through the lens of chemical pressure. Chemical pressure is applied by varying the ionic radius of the non-magnetic B site cation, which either expands or contracts the lattice, in analogy to externally applied pressure. We apply positive chemical pressure by substituting germanium at the B site and negative chemical pressure by substituting lead at the B site. We also consider the effect of platinum substitution, which has nominally negligible chemical pressure effects. In the ytterbium pyrochlores, we find that positive chemical pressure tunes the magnetic ground state from ferromagnetic to antiferromagnetic. Remarkably, we also find that the ytterbium pyrochlores share a ubiquitous form to their low temperature spin dynamics despite their disparate ordered states. In the terbium pyrochlores, we find that positive chemical pressure promotes ferromagnetic correlations - the opposite effect of externally applied pressure. Our studies of platinum pyrochlores reveal that platinum, while non-magnetic, is able to facilitate superexchange pathways. Thus, the magnetic ground states of the platinum pyrochlores are significantly altered from their titanate analogs. The work in this thesis highlights the delicate balance of interactions inherent to rare earth pyrochlore magnetism and shows that chemical pressure is a powerful tool for navigating their phase spaces.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Rare earth pyrochlores have the chemical formula R2B2O7, where R is a magnetic rare earth element and B is a non-magnetic element. Materials of this type are widely studied because they have a propensity to exhibit exotic magnetic properties. In this thesis, we study the effect of varying the size of the non-magnetic B site atom, which is termed chemical pressure. As B is made larger or smaller, the crystal lattice expands or contracts, mimicking the effect of externally applied pressure. High-pressure synthesis techniques were used to prepare R2B2O7 compounds with B site cations that are typically too small (germanium), too large (lead), or too unstable (platinum) under ambient pressure conditions. Our characterizations of these high-pressure materials have revealed that their magnetism is remarkably sensitive to the application of chemical pressure.


title: EXPLORING THE REGULATION OF SECONDARY METABOLITES IN STREPTOMYCES

contributor:
Elliot, Marie
Biology

abstract:
The genus Streptomyces harbors a wealth of untapped pharmaceutical
potential within uncharacterized biosynthetic clusters whose transcription may be
silent or their product undetected. Regulation of these clusters is, in part, managed
by global transcription factors, nucleoid-associated proteins, and pathway-specific
regulatory proteins. Consequently, a complicated interplay of regulatory elements
governs secondary metabolite production and a lack of understanding of this has
undermined efforts to screen for novel drug candidates. In an effort to better
understand this regulation, we have focussed on one highly expressed NAP, and one
silent and cryptic biosynthetic cluster. In parallel, we have leveraged our existing
knowledge to improve our screening of Streptomyces for novel bioactive compounds.
Here, we investigate the nucleoid-associated protein Streptomyces integration
host factor (sIHF), which non-specifically binds DNA and impacts development and
antibiotic production. Through targeted mutations, we probe the interfaces of sIHF
thought responsible for its interactions with DNA and assess the relevance of these
interfaces to in vivo activity. Further, we examine the transcriptionally silent
SCO6429-SCO6438 biosynthetic cluster and attempt to activate transcription from
its promoter by manipulating its potential regulatory proteins. Binding sites for the
putative global regulator cAMP-receptor protein (Crp) in close proximity to this
cluster and a potential pathway specific regulator are examined. Finally, we
overexpress Crp in a library of Streptomyces and assay for novel bioactivity against
known clinical pathogens.
Collectively, this work establishes a foundation for further exploring the
regulatory networks within Streptomyces and how they may be influenced to
discover novel pharmaceuticals.

abstract: Thesis

abstract: Master of Science (MSc)


title: DEVELOPMENT, VALIDATION, AND RELIABILITY OF THE PERSONALIZED EXERCISE QUESTIONNAIRE (PEQ) TO ASSESS EXERCISE FACILITATORS, BARRIERS AND PREFERENCES IN PEOPLE WITH OSTEOPENIA OR OSTEOPOROSIS

title: Validity and reliability study of the Personalized Exercise Questionnaire (PEQ)

contributor:
Macdermid, Joy
Rehabilitation Science

subject: Osteoporosis Exercise Valildity Reliability Development Tool

abstract: One in three women and one in five men will experience a fracture due to osteoporosis in their lifetime. The clinical significance of osteoporosis is largely due to increased fracture rates, particularly in the hip and spine, that may lead to immobility and subsequent hospitalization. This may increase the risk of cardiac complications, pneumonia and pulmonary embolism, significantly impacting in-hospital mortality. It is a major health issue, with an osteoporotic fracture occurring every 3 seconds worldwide. Exercise is often recommended for people with osteoporosis and has been shown to maintain bone mass and reduce falls with fewer side effects. Although exercise has multiple benefits, adherence to this activity is poor, with 50% of those registered in a program dropping out within the first 6 months. One method to increase adherence to exercise is to identify the facilitators, barriers and preferences to physical activity. Identification of these facilitators and barriers may allow researchers and clinicians to design better exercise programs that increase motivation. This dissertation discusses the development of a new tool that can measure the factors that affect exercise adherence and calculates the content and construct validity and the test-retest reliability of the measure in the osteoporosis population. This tool has potential applications in both the research setting and in clinical practice. Investigators can use this tool to survey their population of interest and use this information to leverage the facilitators and limit the barriers in their methodologies when designing activity programs, while clinicians can identify and design better exercise prescriptions for individual clients.

abstract: Thesis

abstract: Master of Health Sciences (MSc)


title: The Animals in Our Stories: Reading Human-Animal History, Kinship, and Inheritance in Asian Diasporic Literature

contributor:
Goellnicht, Donald
English

subject: Literary Animal Studies, Postcolonial Studies, Asian Diasporic Studies

abstract:
This dissertation approaches literary animals in Asian diasporic novels through the concept of drawing close. I am interested in how literary animals can communicate an endeavour to draw animals close, and how literary representations of this closeness imagine normative human-animal relationships otherwise. I argue that even the most subtle literary animal can be read as a practice and expression of drawing animals close, and this closeness reveals itself most directly through each chapter in relation to belonging, family, and inheritance. This project centers around the question: what can stories offer animals?
	I argue that the fields of literary animal studies, postcolonial studies, and Asian diasporic studies need to come together in order to attend not only to the multiple ways that animals inhabit Asian diasporic novels, but also to the particular relationships between postcolonial subjects and animals. I chose novels that navigate relationships to animals often informed by Hindu and Buddhist epistemologies as an intervention in the predominantly Western-focused field of animal studies that has prioritized Western religious traditions, philosophies, and literature. Each chapter of this dissertation examines the diverse ways that authors listen to and represent literary animals, at times acting as a reflection of the desire and efforts to fortify the human-animal boundary, and at other times significantly challenging human exceptionalism by advocating for compassion and interdependence between humans and animals.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: This project looks at animals in Asian North American novels. Whether they are symbolic, mythical, historical, or everyday companions, I argue that paying close attention to animals in stories that are otherwise about humans reveals how they shape our ideas about belonging, family, and inheritance. I focus specifically on three novels: Monique Truong’s The Book of Salt, Madeleine Thien’s Dogs at the Perimeter, and Ruth Ozeki’s A Tale for the Time Being. Each novel represents animals in complex ways that are informed by various ways of knowing the world, such as religious (Hindu and Buddhist), scientific, or cultural knowledges. One central question that directs this dissertation is: what can literary animals teach us when we learn to pay attention to them?


title: Ultra-Wideband Antennas for Medical Imaging and Communication Applications

contributor:
Deen, M. Jamal
Hranilovic, Steve
Electrical and Computer Engineering

subject: ultra-wideband, antennas, medical imaging, communication applications, microwave, electromagnetic

abstract:
 The allocation of 7.5 GHz of bandwidth by the Federal Communication Commission (FCC) for ultra-wideband (UWB) applications has provided an exciting and a challenging opportunity to design short range wireless communication and microwave imaging systems. To fully realize the potential of the UWB, communication and microwave imaging systems are required to operate over the entire UWB frequency band. The combination of the wide bandwidth requirement and the target application of the UWB systems have led to a surge of interest in designing of novel integrated circuits and antennas for the UWB applications. In any wireless communication and microwave imaging system, the antenna has a fundamental effect on the overall performance of the system, and as a result, it has attracted considerable research interest.

 This thesis focuses on the design of UWB antennas that are suitable for UWB cancer detection and wireless communication systems. Two planar antennas, one a
printed monopole antenna, and the other, a printed slot antenna fed with a coplanar waveguide, are presented in this work. First, the antennas have been designed to operate in air, making them suitable for the UWB wireless short range communication applications. Measurement and simulation results indicate that both antennas achieve input impedance matching in a bandwidth of more than 7.5 GHz. The effect on the input matching of the antennas due to the variation in their geometrical parameters has been studied and both antennas have been fully characterized in air. Next, the two antennas have been redesigned to operate in a coupling medium for medical imaging applications. Both antennas achieve return loss of less than -10 dB over the entire UWB spectrum. Also, the antennas have been fully characterized while operating in the coupling medium and in proximity to a human body model. Finally, a two-element antenna array, based on the printed monopole antenna and the printed slot antenna, in co- and cross-polarized array formation, has been designed. The tumor detection capabilities of all antenna arrays for different scenarios have been studied through electromagnetic simulation and measurements.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: ELECTROCHEMISTRY APPLICATIONS FOR SUSTAINABLE ENERGY

contributor:
Kim, Younggy
Civil Engineering

subject:
Bioelectrochemistry
Energy
Sustainability
Junction Potential
Wastewater
Resource Recovery

abstract:
While the terms reduce, reuse, and recycle are common concepts in minimizing resource waste, most people do not think twice about energy as a resource or the large amounts of wasted energy in wastewater treatment and industrial processes. Recovery of wasted energy or reducing the net energy consumption of such processes would save resources and reduce energy costs. This research investigated emerging energy systems for handling wastewater (bioelectrochemical systems) and waste heat (ion exchange membrane systems) to elucidate and quantify thermodynamic and kinetic phenomena in biological and electrochemical reactions.

Bioelectrochemical systems utilize exoelectrogenic microorganisms for wastewater treatment energy recovery in the form of electricity or biogas. The substrate utilization and electron transfer by exoelectrogens to the bioanode have not been clearly explained and thus there are no commonly accepted models for bioanode performance. A comprehensive model for bioanode operation was proposed including equilibrium, kinetics, and microbiological characteristics. The utilization and preference of different organic substrates were also assessed with electrochemical techniques and it was found that linear sweep voltammetry and exchange current are good indicators of whether a substrate is directly or indirectly utilized by exoelectrogenic microorganisms.

This research also investigated ion exchange membrane systems for energy recovery from waste-grade heat, such as that wasted in the steel refinery and power industries, using concentration gradients of ammonium bicarbonate solutions. Estimation of the junction potential (amount of concentration gradient energy) has significant technical difficulties for highly concentrated ammonium bicarbonate solutions (e.g., unknowns in equilibrium speciation and activity coefficient determination). A straightforward estimation method was proposed and found to be able to reliably determine the junction potential across an ion exchange membrane based on conductivity measurement, simplifying the model for junction potential determination.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Characterization and high-throughput screening of the polymyxin resistance enzyme MCR-1

contributor:
Wright, Gerard D.
Biochemistry and Biomedical Sciences

subject:
antibiotic resistance
polymyxin
colistin
MCR-1
Escherichia coli
Gram-negative
antibiotic adjuvant
antibiotic resistance platform
high throughput screening
natural products

abstract:
Polymyxins are potent antibiotics that bind to the outer membrane of Gram-negative bacteria, entering the cell and disrupting the inner membrane, resulting in cell death. They were traditionally used as antibiotics of last resort, but the recent surge of multidrug resistant pathogens has renewed interest in these antibiotics. The emergence of polymyxin resistance determinants such as the recently discovered plasmid-mediated phosphoethanolamine transferase MCR-1 may put a strain on the future effectiveness of this antibiotic.
One method to combat the rise in antibiotic resistant bacteria is through the identification and development of antibiotic adjuvants. These are small molecules that are able to inhibit the resistance mechanism, allowing previously ineffective antibiotics to once again become effective at treating bacterial infections. In this work, a high throughput cell-based screen was conducted using an in-house library of Actinomycete-derived crude cell extracts in order to search for a natural product inhibitor of an E. coli strain expressing mcr-1. In addition, the development of a new enzyme assay was attempted using purified MCR-1 C-terminal catalytic domain and a chromogenic substrate to test enzymatic activity in vitro, in hopes of establishing a simple means of studying inhibition of MCR-1. The structure-function relationship of MCR-1 was also explored by generating amino acid substitutions and studying their effect on the ability of the enzyme to confer resistance to colistin, as well as the generation of MCR-1 transmembrane truncation mutants to determine if it was possible to generate a shorter variant of MCR-1 that retained its enzymatic activity. This work furthers our understanding of the biochemistry and enzymology of MCR-1, and outlines attempts to identify inhibitors of MCR-1 in order to re-sensitize resistant bacteria to polymyxins.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Polymyxins are potent antibiotics that are threatened by the spread of multi-drug resistant bacteria. Resistance to these antibiotics is relatively rare, although the recent discovery of a mobile polymyxin resistance enzyme, MCR-1, threatens the future use of this antibiotic for treating infections, as it can readily transfer to other bacteria. The goal of this work was to search for a natural product inhibitor of MCR-1 in order to reverse its ability to confer resistance to polymyxins. A color-changing assay was conducted with MCR-1 in hopes of establishing a method to study the inhibition of MCR-1 in vitro. Additionally, amino acid substitutions were generated in MCR-1 to better understand how key amino acids affect enzyme function, as well as transmembrane domain truncations to determine if it was possible to create a shorter functioning variant of MCR-1.


title: The Effects of Environment on the Atomic and Molecular Gas Properties of Star-Forming Galaxies

title: Environmental Effects on the ISM of Star-Forming Galaxies

contributor:
Wilson, Christine
Physics and Astronomy

subject:
Galaxies
Interstellar Medium
Star Formation
Groups and Clusters

abstract: Where a galaxy is located has a strong effect on its properties. The dense cluster environment is home to a large population of red, quiescent elliptical galaxies, whereas blue, star-forming, spiral galaxies are common in lower-density environments. This difference is intricately linked to the ability of the galaxy to form new stars and therefore ultimately to the fuel for star formation, the atomic and molecular gas. In this thesis, I use two large JCMT surveys to explore the effects of environment on the atomic gas, molecular gas, and star formation properties of a large sample of nearby gas-rich galaxies. From the NGLS and follow-up studies, I select a sub-sample of 98 HI-flux selected spiral galaxies. I measure their total molecular gas mass using the CO J=3-2 line and combine this data with measurements of their total atomic gas mass using the 21-cm line and star formation rate using attenuation-corrected H-alpha luminosity. I find an enhancement in the mean H2 mass and a higher H2-to-HI ratio for the Virgo Cluster sample. Virgo Cluster galaxies also have longer molecular gas depletion times (H2/SFR), which suggests that they are forming stars at a lower rate relative to their molecular gas reservoirs than non-Virgo galaxies. Next, I collect VLA 21 cm line maps from the VIVA survey and follow-up VLA studies of selected galaxies in the NGLS. I measure the surface density maps of the atomic gas, molecular gas, and star formation rate in order to determine radial trends. I find that the H2 distribution is enhanced near the centre for Virgo Cluster galaxies, along with a steeper total gas (HI + H2) radial profile. I suggest that this is due to the effects of moderate ram pressure stripping, which would strip away low-density gas in the outskirts while enhancing high-density gas near the centre. There are no trends with radius for the molecular gas depletion times, but the longer depletion times for the Virgo Cluster sample is still present. Finally, I use 850 micron continuum observations for 105 star-forming galaxies and CO J=2-1 line observations for 35 galaxies in the initial data release (DR1) of the JINGLE survey. I match the JINGLE galaxies to a SDSS group catalogue and measure environmental parameters such as the host halo mass, environment density, and location in phase space. I find that the molecular gas masses estimated from the 850 μm and CO J=2-1 line observations are well-correlated. The H2-to-HI ratio and the molecular gas depletion times do not appear to vary with stellar mass. I did not find any significant variation with environment in the DR1 sample, but I will apply this framework to the full JINGLE sample once the complete dataset is available.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Clustering Discrete Valued Time Series

contributor:
McNicholas, Paul D.
Mathematics and Statistics

subject:
Clustering
Mixture Models
Discrete Valued Time Series

abstract: There is a need for the development of models that are able to account for discreteness in data, along with its time series properties and correlation. A review of the application of thinning operators to adapt the ARMA recursion to the integer-valued case is first discussed. A class of integer-valued ARMA (INARMA) models arises from this application. Our focus falls on INteger-valued AutoRegressive (INAR) type models. The INAR type models can be used in conjunction with existing model-based clustering techniques to cluster discrete valued time series data. This approach is then illustrated with the addition of autocorrelations. With the use of a finite mixture model, several existing techniques such as the selection of the number of clusters, estimation using expectation-maximization and model selection are applicable. The proposed model is then demonstrated on real data to illustrate its clustering applications.

abstract: Thesis

abstract: Master of Science (MSc)


title: Embedded Deterministic Test for Systems-On-A-Chip

contributor:
Nicolici, Nicola
Electrical and Computer Engineering

subject: embedded, deterministic, test. systems, chip, IP-protected, time-multiplexing

abstract:
 Embedded deterministic test (EDT) is a manufacturing test paradigm that combines the compression advantage of built-in self-test with the high fault coverage of deterministic stimuli inherent to methods based on automatic test pattern generation and external testers. Despite enabling the use of low cost testers for rapidly achieving high fault coverage, EDT must consciously use the available tester channels to ensure non-disruptive scaling to future devices of increased complexity. The focus of this thesis is to introduce a new EDT approach for systems-on-a-chip (SOCs) that are designed using embedded cores that are intellectual property (IP)-protected.

 Following an introduction to integrated circuit testing and an overview of the related work, we define the criteria that must be satisfied by the EDT approaches for the future SOCs of ever growing complexity. Then we observe that the necessary amount of compressed volume of test data transferred from the tester to the embedded cores in an SOC varies significantly during the testing process. This motivates a
novel approach to compressed SOC testing based on time-multiplexing the tester channels. It is shown how the introduction of test control channels will reduce the number of required test data channels which will then have increased usage, as the embedded cores will receive compressed test data only when necessary. Through the use of modular and scalable hardware for on-chip test control and test data decompression, we define a new algorithmic framework for test data compression that is applicable to SOCs comprising IP-protected blocks. Experimental results indicate that our approach compares to the existing approaches for EDT that have similar design criteria and methodology constraints, while providing a seamless integration to low cost test equipment.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Network structures and their effect on a stochastic SIRS model of epilepsy EEG data

contributor:
Bolker, Benjamin
Mathematics and Statistics

subject:
mathematical model
SIRS
epilepsy
EEG

abstract: In this thesis, we consider a stochastic SIRS model of EEG data. The model is built over three different network structures: a random network, a scale-free network, and a small-world network. These models are then fit to an EEG signal from a control individual and an EEG signal from an individual experiencing an epileptic seizure. We are interested in determining whether these models can distinguish between the two data sets, and whether any of the network structures offer a significantly better fit to the data than others; there is also a broader interest in the effects of different network structures on the time series characteristics of an SIRS system.

abstract: Thesis

abstract: Master of Science (MSc)


title: Muslims in Interfaith Marriages in the West: Gender, Globalization, and Pluralism

contributor:
Rothenberg, Celia
Religious Studies

subject:
intermarriage
interfaith
Islam
pluralism
globalization
gender
Ahl al-kitab
social work
sociology
social sciences
psychology
religion
marriage
relationships
children
mixed weddings
mixed marriage
interfaith marriage
Islam in the West
Western societies
gender roles
postmodern muslimness
generational differences
Muslim-Hindu marriages

abstract:
As Muslims increasingly cross ethnic, religious, and social barriers within Western societies, the rate of interfaith marriages continues to rise. As a result, several issues are generated within the Muslim community globally. One of these issues focuses on the subjectivity of Muslim women marrying non-Muslim men since Islamic religious texts may be unclear and indirect regarding the issue. Additionally, Muslims in the West are increasingly exposed to individuals from diverse ethnic and religious backgrounds, which raises the probability of exogamy.
	Many Muslims residing in the West do not have issues with exogamy; it is mostly familial and societal expectations that exude stress when individuals intermarry within the Muslim community. Openness to intermarriage among Muslims in the West can be attributable to differences in faith and identity development of second-generation Muslims growing up in Western countries, which can lead to a differentiation of Muslim identity in comparison to their parents and extended family. Regardless of the taboo and stigma that exist with regard to intermarriage in Islam, Muslim interfaith marriages in the West arguably can be seen as microcosmic representations of positive pluralistic relations in contemporary times.
	Through discussions of data collected for this research, this thesis considers the issues and ideas mentioned above as it considers the experiences of Muslims in interfaith marriages in Western societies by considering notions of gender, globalization, and religious pluralism.

abstract: Thesis

abstract: Master of Arts (MA)


title: Efficiently Combining Multiband Compression and Improved Contrast-Enhancing Frequency Shaping in Hearing Aids

contributor:
Bruce, Ian C.
Electrical and Computer Engineering

subject: Multiband Compression, Hearing Aids, Contrast-enhancing Frequency, Sensorineural hearing, reduced frequency selectivity, Amplification in hearing, Neurophysiology, Impaired cochlea

abstract:
Sensorineural hearing loss imparts two serious hearing deficits in hearing-impaired
people: reduced dynamic range of hearing and reduced frequency selectivity. Psychophysically,
these deficits render loss of speech audibility and speech intelligibility
to a hearing-impaired person. Studies of an impaired cochlea in cats have shown that
the hearing loss originates from damage to or complete loss of inner and outer hair
cells. Neurophysiology of an impaired cochlea in cats shows that the tuning curves
of the auditory nerve fibers become elevated and broadened. Amplification in hearing
aids has been used to restore audibility in hearing-impaired people. Multiband
compression has been commercially available in conventional hearing aids to compensate
for the reduced dynamic range of hearing. However, little has been achieved to
improve the intelligibility of speech in the hearing-impaired people. The aim of this
thesis is to restore not only the speech audibility in a hearing-impaired person, but
also to improve their speech intelligibility through some hearing-aid signal processing.
The compensation technique used in this thesis for speech intelligibility is based on
the hypothesis that a narrowband response of the auditory nerve fibers to speech
signals ensure phonemic discriminability in the central nervous system.

Miller et al. [1999] have proposed contrast-enhancing frequency shaping ( CEFS) to
compensate for the broadband responses of the fibers to first and second formants (Fl
and F2) of a speech stimulus. Bruce [2004] has shown that the multiband compression
can be combined with CEFS without counteracting each other. In Bruce's algorithm,
a multiband compressor is serially combined with a time-domain CEFS filter. The
MICEFS algorithm, herein presented, is a combination of multiband compression and
an improved version of CEFS implemented in the frequency domain. The frequency
domain implementation of MICEFS has improved the time delay response of the
algorithm by 10 ms as compared to series implementation proposed by Bruce. The
total time delay of the MICEFS algorithm is 16 ms, which is still longer than the standard time delay of 10 ms in hearing aids. The MICEFS algorithm was tested on
a computational model of auditory periphery [Bruce et al., 2003] using a synthetic
vowel and a synthetic sentence. The testing paradigm consisted of five conditions:
1) unmodified speech presented to a normal cochlea; 2) speech modified with halfgain
rule presented to an impaired cochlea; 3) CEFS modified speech presented to
the impaired cochlea; 4) speech modified with MICEFS presented to the impaired
cochlea, and; 5) MICEFS-modified speech with some added noise in the formant
estimation presented to an impaired cochlea. The spectral enhancement filter used in
MICEFS has improved the synchrony capture of the fibers to the first three formants
of a speech stimulus. MICEFS has also restored the correct tonotopic representation
in the average discharge rate of the fibers at the first three formants of the speech.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Low Energy Properties of the Antiferromagnetic Quantum Critical Metal in Two Dimensions

contributor:
Lee, Sung-Sik
Physics and Astronomy

subject: Quantum Criticality, Non-Fermi liquids

abstract:
In this thesis, we study the low-energy effective theory for the antiferromagnetic quantum
critical metal in two dimensions. The theory has been the subject of intense study for more than
twenty years, due to the novel physics of non-Fermi liquid metals and its potential relevance to
high-temperature superconductors and heavy-fermion compounds.
In the first part of the thesis, we present the perturbative study of the theory in 3 minus epsilon  space dimensions by extending the earlier one-loop analysis to higher-loop orders. We show that the expansion is not organized by the standard loop expansion, and a two-loop graph becomes as important as one-loop graphs even in the small epsilon limit due to an infrared singularity caused by an emergent quasilocality. This qualitatively changes the nature of the infrared fixed point, and the epsilon expansion is controlled only after the two-loop effect is taken into account. Furthermore, we show that a ratio between velocities emerges as a small parameter, which suppresses a large class of diagrams. We show that the critical exponents do not receive quantum corrections beyond the linear order in epsilon in the limit that the ratio of velocities vanishes.
In the second part of the thesis, we present a nonperturbative solution to the theory in two
dimensions based on an ansatz that is inspired by the perturbative analysis. Being a strongly
coupled theory, it can still be solved reliably in the low-energy limit as quantum fluctuations are
organized by the ratio of velocities that dynamically flows to zero in the low-energy limit. We
predict the exact critical exponents that govern the universal scaling of physical observables at
low temperatures.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Reversible Functionalization of Single-Walled Carbon Nanotubes by Switchable Conjugated Polymers

contributor:
Adronov, Alex
Chemistry

subject:
Conjugated Polymers
Carbon Naonotubes

abstract:
Single-walled carbon nanotubes (SWNTs), since their first discovery in early 1990s, have drawn enormous research attention owing to their extraordinary properties. These excellent optical, electrical, thermal and mechanical properties have enabled SWNTs to make profound impacts in the field of nanotechnology, which includes nanoscale nanoelectronics, chemo-/biosensors, photovoltaics, drug delivery, and advanced nanocomposite materials. However, the as-produced SWNT samples contain a mixture of metallic and semiconducting SWNTs, amorphous carbon, and metal catalyst particles. Also, due to π-π stacking and van der Waals forces, pristine SWNTs tend to form bundles, making them insoluble in most of organic solvents. The poor processibility and purity hinder the direct use of as-produced SWNTs as the material for fabrication of SWNT-based devices. Therefore, the post-synthesis purification is highly required. Conjugated polymers have proven to be efficient SWNT dispersants, but after solution processing, conjugated polymers adhered to the sidewall of SWNTs can not be easily removed and thus negatively affect the performance of the resulting SWNT-based electronic devices. Therefore, polymers that can dissociate from the surface of SWNTs after solution processing is highly desirable.
Apart from the introduction to several other efficient purification methods of SWNTs, Chapter 1 also gives a brief review on reversible functionalization of SWNTs by polymers. The work reported in the literature categorized by the different external stimuli used to reverse the polymer-SWNT association. Chapter 2 describes the design and synthesis of a vinylogous tetrathiafulvalene (TTFV)-based conjugated polymer, which is responsive to pH changes and thus realized reversible functionalization of SWNTs. Chapter 3 describes the design and synthesis of dithiafulvenyl-grafted phenylene ethynylene polymers, which can reversibly interact with SWNTs by changing solvents. Chapter 4 describes the design and synthesis of dithiafulvene (DTF)-based electron-rich conjugated polymers, which can selectively bind with semiconducting SWNTs. In addition, Chapter 5 describes the use of SEC to achieve high-resolution separation, and isolation of surfactant-free metallic and semiconducting SWNTs. This allowed us to study the competition behavior when different ratios of metallic and semiconducting nanotubes are used as the starting material for polymer dispersions. Finally, Chapter 6 describes a side project that involves covalent functionalization of GO using Piers-Rubinsztajn reaction. The functionalized GO is loaded into silicone elastomer to reduce the air permeability and enhance the mechanical strength of the resulting silicone elastomer.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Flowering-time regulators and intercellular salicylic acid contribute to age-related resistance in Arabidopsis thaliana

contributor:
Cameron, Robin
Biology

abstract: Some plants become more resistant to pathogens as they age, a phenomenon known as Age-Related-Resistance (ARR). In this thesis, the Arabidopsis thaliana-Pseudomonas syringae pathosystem was used to explore: i) the association between ARR and the transition to flowering, and ii) the idea that salicylic acid (SA) acts directly on pathogens in the intercellular space during ARR. The ARR phenotypes of flowering-time mutants and wild-type plants induced to flower early by transient exposure to long days suggest that flowering is neither required nor sufficient for ARR, and is not the developmental cue for ARR. Two MADS-domain transcription factors were identified that appear to play distinct roles in the regulation of flowering time and ARR. Specifically, SVP (SHORT VEGETATIVE PHASE) is required for ARR and contributes to intercellular SA accumulation, a key aspect of ARR. Mutant and overexpression analyses suggest that the role of SVP during ARR is to repress SOC1 (SUPPRESSOR OF OVEREXPRESSION OF CO 1), which contributes negatively to ARR, upstream of intercellular SA accumulation. Assessing the in vitro antimicrobial activity of SA under biologically relevant conditions, and estimating the concentration of intercellular SA during ARR, provided convincing evidence that SA acts as an antimicrobial agent in the intercellular space during ARR. Moreover, the results of in vitro biofilm assays and biofilm visualization in the intercellular space suggest that SA also plays a role in reducing P. syringae biofilm formation during ARR. Lastly, I present evidence that intercellular SA also plays a role during pattern- and effector-triggered immunity in young plants. Altogether this work highlights the complex interplay between disease resistance and development, and reveals the potential for direct effects of SA on phytopathogens in vivo. This fundamental knowledge will be useful for the management of existing crops and the development of new disease-resistant varieties.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Optimization of Spiral Inductors and LC Resonators Exploiting Space Mapping Technology

contributor:
Bandler, J.W.
Electrical and Computer Engineering

subject: optimization, spiral inductors, LC resonators, space mapping technology, low noise amplifiers, radio frequency integrated circuits, electromagnetic

abstract:
 This thesis contributes to the computer-aided design (CAD) of spiral inductors and LC resonators with spiral inductors exploiting full-wave electromagnetic (EM) analysis.

 The spiral inductor is widely used in radio frequency integrated circuits (RF ICs), such as low noise amplifiers (LNA) and voltage controlled oscillators (VCO). The design of spiral inductors has a direct influence on the performance of these circuits. Recently proposed optimization methods for spiral inductors are usually based on circuit models, which are computationally efficient but inaccurate compared with full-wave electromagnetic (EM) simulations.

 For the first time, we develop an optimization technique for the design of spiral inductors and LC resonators exploiting both the computational efficiency of a (cheap) circuit model and the accuracy of a full-wave EM analysis, based on geometric programming (GP) and space mapping (SM). With the new technique, we can efficiently obtain EM-validated designs with considerable improvement over those obtained with traditional optimization methods.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Processing of Autonomic Signals During Gastrointestinal Stimulation in Human Subjects

contributor:
Kamath, Markad V.
Electrical and Computer Engineering

abstract: Gastro-intestinal stimulation using a rectal balloon distended with an inflation device is often used to investigate patients with Irritable Bowel Syndrome (IBS). The acquisition and processing of hemodynamic signals from healthy controls and IBS patients during colo-rectal distension is explored in this thesis. Rectal stimulation was performed using a barostat system run on a labview platform. The rectal pressure (using balloon) increased gradually to a user controlled maximum value, held at a 50% discomfort level, followed by a phasic drop in pressure. A baseline and recovery period was used before inflation after deflation states respectively. The blood pressure and heart rate signals were recorded and beat-to-beat variations of these signals were computed. The autonomic signals embedded in the beat -to-beat variations of the hemodynamic variables subjected to power spectral analysis, Wigner-Ville analysis and to the computation of the baroreceptor sensitivity. The objective of the study was to develop signal processing methods to evaluate the autonomic nervous system. Results show that rectal balloon distention perturbs the human ANS and is a powerful tool into assessing the nature of the ANS response in human subjects. Novel methods of studying heart rate and blood pressure using empirical mode decomposition are also proposed.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Transmitter Design for the Broadcast Channel in the MISO Wireless Communication

contributor:
Kirubarajan, Thia
Electrical and Computer Engineering

subject: transmitter design, broadcast channel, MISO wireless communication, uplink spectrum efficiency

abstract:
 There are two popular approaches in the communication between multiple receivers and a base station with multiple antennas: dirty paper coding and multiuser diversity. Dirty paper coding can be rather difficult to realize, which motivates people to find some practical schemes. When there are a lot of users, multiuser diversity requires a lot of feedback which decrease the uplink spectrum efficiency.

 In this paper, we aim to minimize the probability of error subject to the total transmit power constraint and decrease the amount of feedback required by the multiuser diversity instead of trying to achieve the dirty paper coding. There are two main results in this thesis: First, we formulate the minimization of the average probability of error of all the users as a convex optimization problem, subject to the peak or the average power constraints. The proposed transmitter represents a nonlinear
one-to-one mapping between the transmitted data vector and the symbol vector. The transmitted data vector going through the base station antennas is obtained as a solution to the proposed convex error probability optimization problem that can be solved using computationally efficient interior point algorithms. Furthermore, we propose a random unitary beamforming technique to reduce the feedback by selecting a threshold for the users. To improve fairness, an equal ratio scheduling algorithm which could serve the users with different rate requirements is developed. We also give an upper and lower bound on the sum rate achievable in our approach. Monte Carlo simulation results is provided to verify the performance of the proposed algorithms.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Investigation of High-Speed Long-Haul Fiber-Optic Transmission

contributor:
Kumar, Shiva
Electrical and Computer Engineering

subject: high-speed, long-haul, fiber, optic, transmission, wavelength, dispersion, optimization

abstract:
 With the increasing demand for data rate and transmission distance, the trend in fiber-optic communications is to build an ultra-high, long-haul transmission system. One of the challenges in this kind of systems comes from the fiber dispersion and dispersion slope. For the wide-band wavelength-division multiplexing (WDM) system or ultra-high bit rate optical time-division multiplexing (OTDM) system, the dispersion slope could be a serious problem to impair the system performance.

 Many studies have shown that the dispersion and dispersion slope affect the long-haul fiber transmission dramatically, especially for the high-capacity systems. Most of them recommend to totally compensate the dispersion and the dispersion slope simultaneously. And a lot of compensating techniques are proposed. However, it is not easy to realize the simultaneous compensation for the dispersion and dispersion slope in the practical systems. Therefore, the necessity of compensating the dispersion slope in wide-bandwidth systems should be verified.

 We focus on the study of ultra-high bit rate (160-Gb/s) single-channel fiber-optic transmission. The results show that the dispersion slope is not necessary for the dispersion-managed system when the optimal launch parameters are given. Then we present how to find out the optimum in fiber-optic systems and a novel optimizing technology, space mapping technology (SM) is introduced, which has been successfully applied to the electromagnetic area. An application of SM in optical systems is implemented. By using this smart optimization technique, lots of computational efforts for evaluating the fine model in optimization process are saved.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Development and Characterization of a Virtual Impactor Type Dust Flow Concentrator

contributor:
Ching, Chan Y.
Ewing, Dan
Mechanical Engineering

subject: characterization, virtual impactor, type dust, flow concentrator, hydraulic, matter, pressure drop, Reynolds number

abstract: A virtual impactor type dust flow concentrator was developed and an experimental investigation was performed to characterize the hydraulic and particulate matter (PM) separation performance of the device. In particular, the pressure drop characteristics, the ratio of the flow through the two branches, and the PM concentration in the minor and main branch of the flow concentrator were evaluated using experiments on a diesel exhaust rig and an air rig. Tests were performed to examine the effect of the inlet flow Reynolds number, the inlet tube lip position relative to the concentration probe, and the flow distribution between the minor and main branches. Numerical simulations were also performed for a simplified concentrator geometry to examine the flow streamlines and pressure drop. The results showed that the ratio of the concentration in the minor and main flow branches changed as the flow rate in these branches changed, reaching a maximum at a minor flow ratio that depended on the lip position. It was observed the difference of the particulate matter concentration in the minor and main branch was greater for higher inlet Reynolds number. For example, the concentration ratio increased 50% as the Reynolds number increased from 2,200 to 25,700. A similar result was observed when the inlet tube lip was moved further into the concentration body. The pressure losses seem to be mainly caused by the changes in flow directions and the change in the cross sectional areas.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Singularities in Many-Body Quantum Dynamics

contributor:
O'Dell, Duncan
Physics

subject: quantum, dynamics, catastrophes, universality

abstract: One of the most powerful and prized concepts in physics is that of universal behaviour. Universality allows us to make predictions for entire classes of systems without requiring knowledge of the microscopics, and can be found in classical and quantum systems in both equilibrium and in their dynamics. Often in many-body systems, this universal behaviour is found in regimes where effects at macroscopic length scales dominate over microscopic fluctuations, which is particularly true at a phase transition. In this thesis, we will address universality in quantum many-body physics, and its connection to the branch of mathematics known as catastrophe theory (CT). In CT, singularities in a theory take on several universal forms, known as catastrophes, which can be shown to manifest themselves in classical mechanical trajectories. We extend the concept of catastrophes to their wave variants, known as diffraction integrals, and identify how these universal features appear in many-body wavefunctions and observables. Specifically, in Chapter 2, we examine how the wavefunction of a $\delta$-kicked Hamiltonian can be mapped exactly onto the Pearcey function, along with the effects of a phase transition on the diffraction. In Chapter 3, we examine the free-Fermion representation of the one-dimensional transverse-field Ising model in a similar vein, and identify the presence of catastrophes away from and through the critical point.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: In this thesis, we investigate how certain universal structures, known as catastrophes, manifest themselves in quantum many-body systems. These catastrophes, which are associated with singularities somewhere in the theory, have been shown to be universal structures, and are expected to emerge in our study of condensed-matter systems. We will identify the presence of catastrophes, how they arise in specific classes of physical theories, and how they are affected in regimes where other universal behaviour is known to arise: near locations of quantum criticality.


title: Chemical fingerprinting of naphthenic acids by comprehensive two-dimensional gas chromatography mass spectrometry at reclamation sites in the Alberta oil sands

contributor:
Slater, Greg F.
Chemistry

subject:
naphthenic acids
GCxGC
oil sands
two dimensional gas chromatography
mass spectrometry
Alberta oil sands
naphthenic acid fraction compounds
oil sands forensics

abstract:
The processing of bitumen in the Athabasca oil sands region (AOSR) produces extensive volumes of oil sands process-affected water (OSPW) and tailings, which are stored within tailings ponds and settling basins to promote the consolidation of solids and the recycling of water. Oil sands operators are actively investigating dry and wet reclamation strategies in order to reduce their inventory of tailings and return disturbed land back to its original state. An important component of the reclamation of tailings is understanding the environmental fate of naphthenic acids (NAs), which are considered the most toxic constituents of OSPW and tailings. However, since NAs exist as a complex mixture comprised of thousands of compounds from dozens of chemical classes, the characterization of NAs within environmental samples poses significant challenges to analytical chemists.

This dissertation is focused on the characterization of naphthenic acids by comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC/MS). GC×GC/MS offers unparalleled chromatographic separation and peak capacity and has been used in recent years to resolve individual constituents within complex mixtures, including structural isomers. Since the biodegradation and toxicity of NAs is structure-specific and can vary between structural isomers, the profiling of individual NAs by GC×GC/MS is expected to enhance the monitoring of NAs within environmental samples impacted by oil sands activity. In this thesis, GC×GC coupled with time-of-flight mass spectrometry (TOFMS) was used to structurally elucidate a number of ‘unknown’ classical and sulfur-containing naphthenic acids by interpretation of their electron ionization (EI) mass spectra and, if available, confirmed by comparison with the spectra of references standards. GC×GC/TOFMS was also utilized as a fingerprinting tool to assess the temporal and spatial variability at two reclamation sites in the AOSR: Syncrude’s Sandhill Fen reclamation site and Base Mine Lake. Lastly, a methodology was developed which coupled GC×GC with a high resolution quadrupole time-of-flight mass spectrometer (QTOFMS) for the improved profiling of NAs. GC×GC/QTOFMS is advantageous for the monitoring of NAs since it can provide useful fingerprints via isomer distributions, differentiate NAs from several chemical classes, and provide a global overview of the elemental compositions (assigned by mass accuracy) within NA mixtures.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: FABRICATION AND CHARACTERIZATION OF ADVANCED MATERIALS AND COMPOSITES FOR ELECTROCHEMICAL SUPERCAPACITORS

contributor:
Zhitomirsky, Igor
Materials Science and Engineering

subject:
colloid
dispersion
manganese dioxide
hausmannite
carbon nanotubes
polypyrolle
electrophoretic deposition
heterocoagulation
super capacitor
asymmetric

abstract:
Electrochemical supercapacitors (ESs) have attracted great attention due to the advantages of long cycle life, high charge/discharge rate and high power density compared to batteries. Significant improvement in ES performance has been achieved via development of advanced nanostructured materials, such as MnO2 and composite MnO2-MWCNT and PPy-MWCNT electrodes.
In this dissertation, advanced dispersants were developed and investigated for the dispersion, surface modification and electrophoretic deposition (EPD) of metal oxides, multiwalled carbon nanotubes (MWCNT) and polypyrrole (PPy) in different solvents.
Nature-inspired strategies have been developed for the fabrication of MWCNT films and composites. The outstanding colloidal stability of MWCNT, dispersed using anionic bile acids, allowed the EPD of MWCNT. Composite MnO2-MWCNT films were obtained by anodic EPD on Ni plaque and Ni foam substrates. Good dispersion of MWCNT during Py polymerization was achieved and allowed the formation of PPy coated MWCNT. The film and bulk electrodes, prepared by EPD and slurry impregnation methods, respectively, showed high capacitance and good capacitance retention at high charge-discharge rates.
The mechanisms of dispersion and deposition were investigated. Cathodic and anodic EPD of MWCNT, MnO2, Mn3O4 was achieved using positively and negatively charged dispersants. Co-deposition of MWCNT and MnO2 was performed using a co-dispersant, which dispersed both MWCNT and MnO2 in ethanol. Composite films were tested for ES applications.
The efficient dispersion was achieved at relatively low dispersant concentrations due to strong adsorption of the dispersants on the particle surface, which involved the polydentate bonding. We found the possibility of efficient dispersion of MWCNT in ethanol using efficient anionic dispersants. The electrostatic assembly method has been developed, which offers the benefit of improved mixing of MnO2 and MWCNT. The use of different anionic and cationic dispersants allowed the fabrication of electrodes with enhanced capacitance and improved capacitance retention at high charge–discharge rates and high active mass loadings. The asymmetric devices, containing positive MnO2–MWCNT and negative AC–CB electrodes showed promising performance in a voltage window of 1.6 V.
We proposed another novel concept based on electrostatic heterocoagulation of Mn3O4- MWCNT composites in aqueous environment. In this case, various dispersants were selected for adsorption and dispersion of MWCNT and Mn3O4 and this allowed the formation of stable aqueous suspensions of positively charged MWCNT and negatively charged Mn3O4, which facilitated the formation of advanced composites with improved mixing of the components. Testing results showed promising performance of Mn3O4–MWCNT composites for applications in electrodes of electrochemical supercapacitors.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: PRY-1/AXIN REGULATE AGING, LIPID METABOLISM AND SEAM-CELL ASYMMETRIC CELL DIVISION IN CAENORHABDITIS ELEGANS

title: AXIN SCAFFOLD: A SIGNALING MASTER AND METABOLIC RHEOSTAT

contributor:
GUPTA, BHAGWATI
Biology

subject:
C. ELEGANS
WNT SIGNALING
LIPID METABOLISM
AGING

abstract:
The nematode, Caenorhabditis elegans is an ideal animal model to study conserved
mechanisms of developmental and postdevelopmental processes. Here, I
describe the role of an Axin family member, pry-1, in aging, lipid metabolism,
and seam cell development. Our analysis of pry-1 animals showed a catastrophic
collapse of adult lifespan, which was accompanied with hallmarks of accelerated
aging. Transcriptome profiling of pry-1 mutants revealed altered expression of
genes associated with aging and lipid metabolism such as vitellogenins, fatty acid
desaturases, lipases, fatty acid transporters and genes involved in cuticle synthesis.
Consistent with this, pry-1 animals display significantly reduced levels of somatic
lipids. Knockdowns of vitellogenins in the pry-1 background restored lifespan and
lipid levels, suggesting that vitellogenins are necessary to mediate pry-1 function
in aging and lipid metabolic processes. Additionally, lowered expression of desaturases
and lipidomics analysis provided evidence of reduced fatty acid synthesis in
pry-1 animals. In agreement with this, an exogenous supply of oleic acid restored
depleted lipids in somatic tissues in addition to suppressing the short-lived phenotype
of worms. In addition, transcriptome profiling for differentially expressed
miRNAs in pry-1(mu38) identified heterochronic miRNAs (lin-4 and let-7 -family
members) to act downstream of pry-1 /Axin. In C. elegans, these miRNAs are
known to robustly regulate the stem-like, seam cell division. Loss of pry-1 function
caused heterochronic defects such that the seam cells divide precociously to
produce additional cells. The pry-1-miRNAs are involved in mediating silencing of
the heterochronic gene, hbl-1, a C. elegans hunchback homolog, to regulate seam
cell division. Furthermore, I report identification of novel miRNAs from C. elegans
and C. briggsae. Overall, our findings demonstrate a novel role of the Wnt signaling
regulator, pry-1/Axin, in the maintenance of adult lifespan that involves lipid
homeostasis and regulation of heterochronic miRNA to control the developmental
timing of seam cell division in C. elegans.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Role and Molecular Mechanisms of Rex1 in Pluripotent Stem Cells

contributor:
Draper, Jonathan
Biochemistry and Biomedical Sciences

subject:
Pluripotent Stem Cell
Biochemistry
Rex1/Zfp42

abstract:
Pluripotent stem cells (PSCs) are unique in their capability to self-renew and
differentiate into cell types of all three embryonic germ layers. Since their discovery, PSCs
have become an indispensable tool for modeling development, disease onset/progression,
and drug discovery. The pluripotent state is known to be regulated by a core network of
transcription factors including Oct4, Sox2, and Nanog. However, the roles of other
contributing transcription factors remain understudied. Our research focused on defining
the roles and molecular mechanisms of Rex1, a zinc finger transcription factor whose
expression is strongly correlated with the pluripotent state. Attempts by our lab to elucidate
the role of Rex1 in embryonic stem cells (ESCs) revealed the presence of two smaller
protein products that result from the initiation of translation at downstream start codons
within the REX1 open reading frame. We hypothesized that the full-length Rex1 protein
and its shorter alternative translation isoforms were acting to regulate the expression of
lineage-determining genes in PSCs. To evaluate this hypothesis, we generated mouse
embryonic stem cell (mESC) lines expressing FLAG-tagged versions of the full-length
Rex1 protein, and its isoforms, from the endogenous locus. Through the use of these lines,
we demonstrated the formation of multiple Rex1 isoforms by alternative translation, a novel
observation that has yet to be reported. Furthermore, our results indicate that Rex1 is a
negative regulator of differentiation-related genes and endogenous retroviral elements,
suggesting Rex1 is acting to maintain the tightly regulated transcriptional network of
pluripotency, while also maintaining genomic integrity through the repression of repetitive
elements.

abstract: Thesis

abstract: Master of Science (MSc)


title: Some Contributions to Distribution Theory and Applications

contributor:
Balakrishnan, Narayanaswamy
Mathematics and Statistics

subject: Distribution Theory

subject: Quantum Mechanics

subject: Molecular Biology

subject: Simpson's Paradox

subject: Optimal Transportation

subject: Variational Characterization of Distributions

subject: Statistical Inference

subject: Von Mises Distribution

subject: Inverse Stereographic Normal Distribution

subject: Orthogonal Group

subject: Protein Folding Problem

subject: Symmetric Order Statistics

subject: Prisoner's Dilemma

subject: Strichartz Estimates

subject: Elliptical Distributions

subject: Measure of Amalgamation

subject: Big Data

subject: Consensus Monte Carlo Algorithm

subject: Bohr Radius

subject: Quantum Harmonic Oscillator

subject: Nonlinear Schrödinger Equation

subject: Characteristic Function

subject: Optimization Algorithms

subject: Symmetric Distributions

abstract:
In this thesis, we present some new results in distribution theory for both discrete and continuous random variables, together with  their motivating applications.

We start with some results about the Multivariate Gaussian Distribution and its characterization as a maximizer of the Strichartz Estimates. Then, we present some characterizations of discrete and continuous distributions through ideas coming from optimal transportation. After this, we pass to the Simpson's Paradox and see that it is ubiquitous and it appears in Quantum Mechanics as well. We conclude with a group of results about discrete and continuous distributions invariant under symmetries, in particular invariant under the groups $A_1$, an elliptical version of $O(n)$ and $\mathbb{T}^n$.

As mentioned, all the results proved in this thesis are motivated by their applications in different research areas. The applications will be thoroughly discussed. We have tried to keep each chapter self-contained and recalled results from other chapters when needed.

The following is a more precise summary of the results discussed in each chapter.

In chapter \ref{chapter 2}, we discuss a variational characterization of the Multivariate Normal distribution (MVN) as a maximizer of the Strichartz Estimates. Strichartz Estimates appear as a fundamental tool in the proof of wellposedness results for dispersive PDEs. With respect to the characterization of the MVN distribution as a maximizer of the entropy functional, the characterization as a maximizer of the Strichartz Estimate does not require the constraint of fixed variance. In this chapter, we compute the precise optimal constant for the whole range of Strichartz admissible exponents, discuss the connection of this problem to Restriction Theorems in Fourier analysis and give some statistical properties of the family of Gaussian Distributions which maximize the Strichartz estimates, such as Fisher Information, Index of Dispersion and Stochastic Ordering. We conclude this chapter presenting an optimization algorithm to compute numerically the maximizers.

Chapter \ref{chapter 3} is devoted to the characterization of distributions by means of techniques from Optimal Transportation and the Monge-Amp\`{e}re equation. We  give emphasis to methods to do statistical inference for distributions that do not possess good regularity, decay or integrability properties. For example, distributions which do not admit a finite expected value, such as the Cauchy distribution. The main tool used here is a modified version of the characteristic function (a particular case of the Fourier Transform). An important motivation to develop these tools come from Big Data analysis and in particular the Consensus Monte Carlo Algorithm.

In chapter \ref{chapter 4}, we study the \emph{Simpson's Paradox}. The \emph{Simpson's Paradox} is the phenomenon that appears in some datasets, where subgroups with a common trend (say, all negative trend) show the reverse trend when they are aggregated (say, positive trend). Even if this issue has an elementary mathematical explanation, the statistical implications are deep. Basic examples appear in arithmetic, geometry, linear algebra, statistics, game theory, sociology (e.g. gender bias in the graduate school admission process) and so on and so forth. In our new results, we prove the occurrence of the \emph{Simpson's Paradox} in Quantum Mechanics. In particular, we prove that the \emph{Simpson's Paradox} occurs for solutions of the \emph{Quantum Harmonic Oscillator} both in the stationary case and in the non-stationary case. We prove that the phenomenon is not isolated and that it appears (asymptotically) in the context of the \emph{Nonlinear Schr\"{o}dinger Equation} as well. The likelihood of the \emph{Simpson's Paradox} in Quantum Mechanics and the physical implications are also discussed.

Chapter \ref{chapter 5} contains some new results about distributions with symmetries. We first discuss a result on symmetric order statistics. We prove that the symmetry of any of the order statistics is equivalent to the symmetry of the underlying distribution. Then, we characterize elliptical distributions through group invariance and give some properties. Finally, we study geometric probability distributions on the torus with applications to molecular biology. In particular, we introduce a new family of distributions generated through stereographic projection, give several properties of them and compare them with the Von-Mises distribution and its multivariate extensions.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Vigilantism in Moral Philosophy

contributor:
Waluchow, Wil
Gedge, Elisabeth
Philosophy

subject:
vigilante
vigilantism
moral philosophy
legal philosophy

abstract: Vigilantism is an underdeveloped concept in scholarly discourse, particularly within the field of philosophy. My definition of vigilantism is: private citizens who engage in illegal coercive activity, against alleged transgressors of some normative code. Vigilantes seek to fulfill some conception of justice, and in doing so, they presume upon the state's authority. This definition excludes similar activities, like police brutality or terrorism. It also improves upon earlier definitions from other scholars. There are many potential objections to the practice of vigilantism as a whole, and there are many examples of unjustified, immoral vigilantism. However, vigilantism can be morally justified under the following circumstances: a breakdown of the legal system, protection of vulnerable individuals, proportional punishments, fair treatment, attempts to mend the larger social issues, and the advancement of justice. Depending on the particular circumstances, vigilantism can be morally justified, morally optimal, or unjustified. Since I can only provide a cursory examination of vigilantism, these ideas need more rigorous investigation and development. Further discussion on this subject is very important, given our volatile political climate.

abstract: Thesis

abstract: Master of Arts (MA)

abstract: Vigilantism requires more careful discussion in scholarly discourse, particularly given recent political developments in Canada and the United States. Although there is some earlier material on the subject, it is inconsistent and scattered across academic fields. Within this thesis, I develop a philosophical definition of vigilantism, and discuss how it differs things like terrorism or police brutality. I also develop a preliminary account of the morality of vigilantism, exploring several reasonable concerns with the practice as a whole. In spite of these issues, vigilantism can be morally justified under a particular set of circumstances, which are difficult but not impossible to fulfill. However, there is much more work to be done on the subject, in order to develop a robust understanding of vigilantism.


title: THE ROLE OF MAST CELLS IN GUT PHYSIOLOGY, BRAIN CHEMISTRY, AND BEHAVIOUR

contributor:
Forsythe, Paul
Medical Sciences

subject:
Gut
Mast Cells
Brain
Behaviour
Anxiety
IBS

abstract:
Background and Research Aim: Stress affects the immune system, which influences host physiology. Mast cells have been associated with several stress-induced changes in gut physiology. Mast cells also have the potential to influence the brain and behaviour. We investigated how mast cells influenced the body, brain, and behaviour during stress.
Methodology: We investigated the behaviour of mast cell deficient animals and deficient animals that received whole bone marrow (WBM) transplants. We also studied the effects of mast cell stabilization during stress on changes in gut motility, via ex vivo. recordings of intestinal segments, and brain, via behavioural measurements and flow cytometry analysis of proinflammatory monocyte trafficking to the brain.
Results: Mast cell deficiency leads to several behavioural changes related to activity level, exploration, and sociability. Furthermore, deficient animals that received WBM transplants demonstrated social and anxiety-like behaviour that differed from their deficient counterparts. Mast cell stabilization during stress prevented many of the stress-induced changes in gut motility commonly observed in the intestine. Mast cell stabilization during stress also prevented proinflammatory monocyte trafficking to the brain and was associated with reduced anxiety-like behaviour.
Conclusion: Our findings support the role of mast cells in baseline behaviour, suggesting the presence of mast cells is needed for normal social and anxiety-related functioning. We also found that mast cell activation contributes to stress-induced intestinal dysmotility, suggesting that mast cells should be a target for interventions of stress-related gut motility disorders, such as irritable bowel syndrome. Lastly, our findings on the role of mast cells in monocyte trafficking and anxiety adds to our knowledge of neuroimmune interactions during stress and supports a potential role for mast cells in anxiety-related mood disorders, where stabilization of mast cells during stressful events may be of benefit.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Stress affects the immune system, which influences the body. Mast cells of the immune system are involved in several stress-induced changes in the body. They can also influence the brain and behaviour. We investigated how mast cells influence the changes that occur in the gut, brain, and behaviour during stress. Using mouse models, we prevented mast cells from activating during stress and looked at this effect on gut movement, changes in brain chemistry, and behaviour. We also compared the behaviour of mast cell deficient mice and deficient mice that gained mast cells. We found that by preventing mast cells from activating during stress, we can prevent several stress-associated changes in gut movement, brain chemistry, and anxiety behaviour. We also found that mast cells affect anxiety and social behaviour. These results suggest that mast cells impact the body, brain chemistry, and behaviour in stress and non-stress conditions.