title: Free Radical Polymerization of Styrene in a Batch Reactor

contributor:
Hodgins, J. W.
Hamielec, A. E.
Chemical Engineering

subject: free-radical, polymerization, styrene, batch reactor

abstract:
 The free radical polymerization of styrene in benzene using azo-bisisobutyronitrile as a catalyst has been studied both theoretically and experimentally. The molecular-weight
distribution and conversion are predicted on the basis of a simplified kinetic mechanism, neglecting a number of minor side reactions. The steady-state assumption is investigated and is shown to be applicable in the case of styrene polymerization, a pseudo-steady-state being reached in less than one second. Using the steady-state approach a relatively simple kinetic model is obtained, suitable for computer simulation. The prime variables consist of the ordinary reaction conditions such as monomer concentration, solvent concentration,
catalyst concentration, reaction temperature and reaction time.

 The polymerization was carried out isothermally in a stirred batch reactor from which samples were abstracted at
various time intervals. Conversion was determined by precipitating the polymer with methanol, filtering, and weighing, and the molecular-weight distribution has been obtained by
gel-permeation chromatography. A computer program was written to interpret the variation of refractive index with respect to the elution volume trace from the chromatograph, giving a
readout of molecular chain length in monomer units versus weight fraction.

 The experimentally obtained conversion and distribution curves are compared with those obtained from the mathematical model. Except for bulk polymerization agreement between the two is good. Good agreement for conversion is obtained for all cases if the catalyst initiation efficiency is adjusted according to the monomer or solvent concentration. However, the same considerations do not give good agreement for molecular-weight distribution. Rather it appears that the rate constants instead of the catalyst efficiency are monomer or solvent concentration dependent, which would explain the discrepancies.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: The Attenuation of Solar Radiation in Urban Atmospheres

contributor:
Davies, J. A.
Geography

subject: solar radiation, urban, atmospheres, attenuation

abstract:
 Unsworth and Monteith's (1972) aerosol attenuation coefficient TA was calculated with hourly cloudless data at four North American and four European stations for varying time periods. Monthly and seasonal turbidity trends were examined. Annual cycles were observed with summer maximums and winter minimums. The North American stations were less
turbid and had more pronounced trends than the European stations. Both air mass origin and local weather affect the turbidity. Local sources of pollution have a significant effect on turbidity most notably in large urban centres.

abstract: Thesis

abstract: Candidate in Philosophy


title: Base-Catalyzed Protium-Deuterium Exchange in Bicyclo[2.2.1.]Heptanones

contributor:
Werstiuk, N. H.
Chemistry

subject: base-catalyzed, protium-deuterium, exchange, heptanones, magnetic resonance

abstract:
 Several ketones in the bicyclo{2.2.1.}heptane system, many of them previously unknown, have been prepared and characterized; these included monoketones, enones and diones. They are listed in Fig. II-1.

 The conformations of norbornane-2,5-dione (27) and 3,3-dimethyl-norbornane-2,5-dione (26) have been carefully examined by nuclear magnetic resonance spectroscopy. These compounds have been found to exist in two different synchro twist conformations.^76

 The stereochemistry of base-catalyzed protium-deuterium exchange of the diones 25, 26 and 27 has been examined and has been found to be similar to the stereochemistry of exchange in monoketones previously observed in these systems, viz exo exchange is considerably more rapid than endo exchange.

 The rates of NaOD-catalyzed protium-deuterium exchange of the ketones, enones and diones have been measured in 60 % dioxane-D2O at 25°. The rate data is shown in Table II-4. Kinetic analysis showed that these rate constants represent the true reactivity of the hydrogen for which the rate of exchange was measured.

 A study of the 13C chemical shift of highly substituted bicyclo{2.2.1.}heptanes has been undertaken, and also a study of the 13C-H coupling constants of many of these compounds has been made. The results are listed in Tables II-6 and II-8. They suggest that there are no unusual hybridization effects at the enolizable carbon in the diones and enones under study.

 The rate data, together with some literature data, shows that hybridization effects, torsional effects, conformational effects and strain effects are of minor importance in the exchange reactions. The rate acceleration observed in the dione systems is almost entirely accountable by an inductive effect of the second carbonyl group, with very little homoconjugative participation.

 The kinetic results suggest that an enol is the intermediate in the enolization reaction, and that the transition state occurs relatively early along the reaction coordinate.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: An X-Ray Crystallographic Study of (Zn, Cd, Mn)3(PO4)2 Compounds

contributor:
Calvo, C.
Chemical Physics

subject: x-ray, crystallographic, compounds, temperature, mineral, ion

abstract: The crystal structures of four compounds of the type (Zn,Cd,Mn)3(PO4)2 have been determined by X-ray diffraction methods. These structures are the high temperature (β) phase of Zn3(PO4)2, the related structures of β1-Mn3(PO4)2 and β1-Cd3(PO4)2, and the structure of a member of a solid solution of median composition Zn2Cd(PO4)2 which is similar in structure to the mineral graftonite. The orthophosphates of the small divalent metal ions have been separated into four structure classes and the stability of each of these classes is discussed in terms of cation concentration and the types of cation sites which exist in these structures. The correlation of a host crystal structure and the luminescence of Mn++ when this ion is added as an impurity is also discussed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Magnetic Inks for Printing Functional Materials

contributor:
Ishwar, Puri
Mechanical Engineering

abstract: The demand for new novel materials has never been higher. This is driven by the advancement in technologies such as wearable electronics. As more novel applications emerge, the need for materials fit for the tasks follows. Many emerging fabrication techniques such as additive manufacturing strive to claim governance over new material properties. However, they remain largely subject to the use of homogeneous materials to create structures. Comparatively, natural structures, such as the cuticle arrangement in dragonfly wings dictate the functionality of the wing, lending one of the most efficient and manoeuvrable flyers on earth. Understanding that heterogeneities define function, we explore simple benchtop techniques to create readily functional materials. Such techniques involve the use of magnetic inks, which can be remotely manipulated using external magnetic fields. When miscible ferrofluid droplets are guided with a magnet through a viscous prepolymer, they trace trail patterns in their wake. It is shown that such patterns create pattern-specific reductions in the elastic modulus compared to the matrix. When the ink is comprised of magnetic carbon nanotubes, we show the simple dynamic-assembly of the ink into conductive networks. The networks are easily encased in a rubber like matrix to readily obtain functioning strain and oil sensors. In a similar manner biosensors are created using the immobilization of antibodies on the surface the nanotubes. The fabrication technique results in simple and economical sensors able to detect target biomarkers within sixty seconds. We equally explore how cells can be manipulated using engineered buffer solutions and magnetic field geometries, leading to simulations to optimize cell separation in microfluidic channels and macroscale patterning of blood and cancer cells. Magnetic inks can open an avenue to facile and economic fabrication techniques in all facets of industrial applications spanning from wearable electronics to biological sensors to tissue engineering.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Our obsessive pursuit of technological advancement demands the creation of a new material arsenal. Such materials will bridge the gap between future novel applications and the concepts from which they once stemmed. We draw inspiration from the natural world and find that materials are grouped into specific patterns helping in defining function. Such examples include the dragonfly’s wing with its microscopic cuticle arrangement, helping in achieving optimum lift. To create readily functional materials we manipulate magnetic inks using external magnetic fields. Such ink droplets can be guided through a viscous polymer, leaving 3D trails. Once the polymer is cured, the local mechanical properties are altered. We use magnetic carbon nanotube inks to print strain, oil and biosensors in a fast fabrication technique. Similarly, cells can be easily manipulated to achieve cellular structures, creating biological functional materials. Magnetic inks thus offer a simple avenue to readily fabricate functional materials.


title: Be myself experiences of the post-90s of Chinese international students in Canadian universities

contributor:
Rachel, Zhou
Social Work

subject:
Chinese international students
identity
experiences
services

abstract: This research aims to understand the experiences of a new generation of Chinese international students in Canadian universities and the role of their identities in shaping such experiences, including their resistance toward stereotypes. Data was collected through semi-structural, in-depth interviews with eight international students who were studying at universities in Southern Ontario, were from mainland China and were born during 1990s. The study leads to several major findings. First, these students did not necessarily internalize stereotypes about Chinese international students, China and Chinese culture from other groups, producing from lack of culture exchange, language barrier, cultural difference and the biased mass media, and that they also made their efforts to change this situation. Second, participants appeared to have different relationships with three groups in Chinese student communities. Third, informal support from individual social network was perceived much more effective than formal services on campus. Fourth, they viewed challenges they had experienced as a process of growth, and advanced technology and globalization also helped them to better adapt to the new environment. Across these findings, there is a dynamic relationship between these students’ experiences in Canadian universities and their identities in relation to their national, ethno-cultural, generational and international backgrounds. Although their generally positive and critical thinking on their experiences of studying abroad is related to their generation-related resources, common challenges they collectively encountered also indicate the importance of accessible institutional support.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Development of an Advanced Two-Dimensional Microdosimetric Detector based on THick Gas Electron Multipliers

title: Development of an Advanced 2D THGEM Microdosimetric Detector

contributor:
Byun, Soo-Hyun
Medical Physics

subject:
Microdosimetry
2D Detector development
THGEM
Radiation detection and measurement
Multi-Input DSP
Tissue-equivalent proportional counter
Neutron spatial dose distribution
Neutron weighting factors
Strong mixed radiation field
Nanodosimetry

abstract:
The THick Gas Electron Multiplier (THGEM) based tissue-equivalent proportional counter (TEPC) has been proven to be useful for microdosimetry due to its flexibility in varying the gaseous sensitive volume and achieving high multiplication gain. Aiming at measuring the spatial distribution of radiation dose for mixed neutron-gamma fields, an advanced two-dimensional (2D) THGEM TEPC was designed and constructed at McMaster University which will enable us to overcome the operational limitation of the classical TEPCs, particularly for high dose rate fields. Compared to the traditional TEPCs, anode wire electrodes were replaced by THGEM layer, which not only enhances the gas multiplication gain but also offers a flexible and convenient fabrication or building 2D detectors.
The 2D THGEM TEPC consists of an array of 3×3 sensitive volumes, equivalent to 9 individual TEPCs, each of which has a dimension of 5 mm diameter and length. Taking the overall cost, size and flexibility into account, to process 9 detectors signals simultaneously, a multi-input digital pulse processing system was developed by using modern microcontrollers, each of which is coupled to a 12-bit sampling ADC with a sampling rate of 42 Msps. The signal processing system was tested using a NaI(Tl) detector, which has proven that is it faster than a traditional analogue system and a commercial digital system. Using the McMaster Tandetron 7Li(p,n) accelerator neutron source, both fundamental detector performance, as well as neutron dosimetric response of the 2D THGEM TEPC, has been extensively investigated and compared to the data acquired by a spherical TEPC. It was shown that the microdosimetric response and the measured absorbed dose rate of the 2D THGEM detector developed in this study are comparable to the standard 1/2" TEPC which is commercially available.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Whole-Rock Pb Isotope Delineation of Archean and Paleoproterozoic Crustal Terranes in the Grenville Province and Adjacent Makkovik Province: Evidence for Juvenile Crustal Growth during the Paleoproterozoic

contributor:
Dickin, Alan
Geography and Earth Sciences

subject:
Isotope Geology
Pb Mapping
Grenville Province
Makkovik Province

abstract:
The Grenville Province and adjacent Makkovik Province represent two long-lived ancient orogenic belts that contain remnants of Paleoproterozoic crust accreted to the southeastern Laurentian margin during the Great Proterozoic Accretionary Orogen (GPAO).  However, the addition of juvenile Paleoproterozoic crust to the Archean craton during this period was followed by a span of intermittent ensialic arc magmatism and high-grade metamorphism that overprinted much of the early- to mid- Proterozoic geologic history of the region.  As a result, these ancient orogenic belts contain cryptic terrane boundaries that require extensive geochronologic mapping in order to reconstruct the accretionary and collisional growth of the southeastern Canadian Shield.
Accreted Proterozoic terranes in the Grenville and Makkovik Provinces have been previously mapped using Nd isotopes in order to determine their crustal formation ages and the boundaries between them.  Since the U-Pb isotope system has completely different chemical behaviour to the Sm-Nd system, whole-rock Pb isotope analysis provides an independent method to test the results of Nd isotope analysis.  Likewise, Pb isotope mapping acts as a useful tool for determining the exhumation of highly metamorphosed crust, as uranium is preferentially transported from lower crustal levels into the upper crust during regional metamorphism.  Therefore, whole-rock Pb isotope analysis was performed on over 200 Archean and Proterozoic gneisses from the SW Grenville Province and Makkovik Province in order to 1) differentiate areas of accreted Paleoproterozoic crust from the reworked Archean margin, 2) test the location of the Archean-Proterozoic suture previously mapped in both regions by Nd model ages, and 3) investigate the variable degrees of crustal burial-uplift within the Archean foreland of the SW Grenville Province that was exhumed during the Grenville orogeny.
In the Makkovik Province, whole-rock Pb isotope data from the Cape Harrison domain are comparable with published Pb data from the central Ketilidian mobile belt of southern Greenland.  The similarity in Pb signatures between the two belts points to a crustal component in the Cape Harrison domain that was derived from a Proterozoic mantle-derived source with minimal input from older Archean crust.  This is largely different from published Pb signatures for the Aillik domain in southeastern Labrador and border zone in southern Greenland that suggests a crustal component comprised of reworked Archean crust analogous to the pre-Makkovikian Laurentian foreland.  Comparison of new and published Pb data from the Makkovik Province and southern Greenland in turn helps to constrain a revised single arc accretionary model for the Makkovik Province.
Previous Nd isotope mapping in the SW Grenville Province revels a break in model ages inferred by authors as a cryptic collisional suture between the reworked Archean foreland and an accreted Paleoproterozoic arc.  However, some workers have suggested that this terrane actually consists of Archean crust that was magmatically reworked in the Mesoproterozoic.  Whole-rock Pb isotope data presented in this study points to a crustal component south of the proposed suture in Ontario that was derived from a Paleoproterozoic mantle source and subsequently reworked by ensialic arc magmatism during the Mesoproterozoic.  North of the suture, Pb data reveals an Archean crustal component analogous to reworked Superior basement that was exhumed from different crustal levels during the Grenville orogeny.  Here, regions of anomalously radiogenic and unradiogenic Pb signatures differentiate the Archean-Proterozoic suture in Ontario from a tectonic duplex in western Quebec.

abstract: Thesis

abstract: Master of Science (MSc)


title: CMOS BASED SINGLE PHOTON AVALANCHE DIODE AND TIME-TO-DIGITAL CONVERTER TOWARDS PET IMAGING APPLICATIONS

contributor:
Deen, Jamal
Peng, Hao
Electrical and Computer Engineering

abstract:
Time-of-flight (ToF) positron emission tomography (PET) is a non-invasive, functional biomedical imaging modality. It can be used to determine the metabolic activity difference between lesion and normal cells, thus, making it possible to detect tumors at their early stages. In such a system, photomultiplier tubes (PMTs) are typically employed as the photon sensors. However, PMTs are of large size, have fragile package, consume large power, require high bias voltage and are costly. To pursue the benefits of ToF PET system, there is a growing need for research on new types of photodetectors and photo-detection systems.
This work focuses on studying and building a compact, low-cost time-of-flight photo-sensing system. To achieve this goal, we choose a standard digital CMOS technology to design and fabricate the photodetectors and associated electronics. A CMOS single photon avalanche diode (SPAD) is selected because of its low-cost, ultra-high light sensitivity and fast speed. Being implemented in IBM’s 130nm CMOS process, the impacts of silicide layer on the overall performances of the SPAD are investigated. By eliminating silicide on the active area of SPAD, a fivefold improvement in both dark noise and photon detection efficiency are demonstrated. Then, a SPAD comprehensive analytical model is proposed and implemented in Verilog-A hardware description language. This model includes all the noise sources and will provide useful guidance in optimizing SPAD and the associated circuits.
A time-to-digital converter (TDC) is proposed and designed in the same 130nm CMOS process. The TDC is capable to digitize time intervals with 7.3ps resolution and covers up to 9ns dynamic range. The proposed TDC achieves state-of-the-art low power consumption. It will be used to extract the time-of-flight information, and to improve the image’s single-to-noise ratio (SNR) in a ToF PET imaging system.
Finally, a time-of-flight sensing system prototype is built by integrating the CMOS SPADs and TDC on a printed circuit board. Based on the preliminary measurement results, this system achieves 440ps coincidence timing resolution. Factors of 2.5 and 6.1 improvements in image SNR and effective sensitivity, respectively, are expected with this prototype in ToF PET imaging applications.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Effect of Cyclic Deformation on the Corrosion of Coated AA6xxx Hem Flanges

contributor:
Kish, Joseph
McDermid, Joseph
Materials Science and Engineering

abstract: The cyclic corrosion and cyclic deformation behaviour of AA6022 and AA6111 coated au-tomotive hem flanges were investigated. Neutron radiography, in conjunction with a gado-linium (III) nitrate (Gd(NO3)3) solution, was used to reveal the existence of an interconnect-ed network of pores within the adhesive layer of the hem flange coupons. Cyclic corrosion tests revealed that the inner compressive surface of the outer sheet (area B) was the weak link in the corrosion resistance of a hem flange due to the high degree of plastic deformation combined with micro-cracking present in this area. Cyclic deformation test revealed that cyclic deformation caused cracking in the adhesive layer and subsequent loss of load bear-ing ability. The cyclic deformation of pre-exposed hem flange coupons showed that cyclic corrosion exposure resulted in adhesive embrittlement and an earlier initiation of cracking in the adhesive layer. The current evidence was not enough to demonstrate that the corrosion resistance of a hem flange coupon is altered by the damage accumulated during cyclic de-formation. An imposed low-level static stress on pre-cracked hem flange coupons was found to have a synergistic effect with the cyclic corrosion environment and resulted in ad-hesive failure at the adhesive-metal interface, thereby exposing new sites for corrosion.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Understanding and Improving Morbidity and Mortality after Hip Fracture

contributor:
Bhandari, Mohit
Devereaux, PJ
Health Research Methodology

subject:
Hip Fracture
Observational Study
Systematic Review
Morbidity and Mortality

abstract:
Hip fractures are common injuries with devastating consequences, including high rates of morbidity and mortality. The purpose of my thesis was to lay the foundation for further research which can fully explore: i) the epidemiology of morbidity and mortality following hip fracture; ii) risk factors for poor outcomes following hip fracture; iii) causes and pathways to mortality following hip fracture; iv) secondary prevention of morbidity and mortality following hip fracture; and v) potential interventions to improve outcomes following hip fracture.
To this end, I will first detail the design, execution, results, and ‘lessons learned’ of a prospective observational pilot cohort study that recruited 100 consecutive patients aged ≥18 years presenting with a hip fracture to the Juravinski Hospital and Cancer Centre of the Hamilton Health Sciences. The primary aim of this pilot study was to assess the feasibility of a larger prospective international cohort study.
Second, I will present a systematic review and meta-analysis of a promising intervention that consisted of multi-disciplinary (specifically geriatrician-led) co-management of hip fracture patients. This intervention has previously been shown to reduce mortality and length of stay following hip fracture. The meta-analysis presented will determine the effectiveness of this intervention in reducing the incidence, duration, and severity of delirium—a common condition following hip fracture.

abstract: Thesis

abstract: Master of Science (MSc)


title: Thermal, morpholine, and radiation stressor effects on the embryonic development of lake whitefish (Coregonus clupeaformis) and round whitefish (Prosopium cylindraceum)

title: Environmental stressor effects on whitefish embryogenesis

contributor:
Wilson, Joanna
Biology

subject:
Embryo development
Lake whitefish
Round whitefish
Fluctuating Temperatures
Morpholine
Low-dose irradiation

abstract:
Lake and round whitefish are cold-adapted freshwater species with similar life
histories and spawning behaviours. There have been several studies on the embryonic
development of both species (particularly for lake whitefish), most utilizing constant
temperatures. However, temperatures fluctuate in the field due to natural (e.g. seasonal
changes) and anthropogenic (e.g. water discharged from once-through cooling processes)
effects. Releases from once-through cooling processes may contain low levels of
chemicals (e.g. morpholine) and radiation (e.g. tritium). This thesis examined and
compared the impacts of thermal, morpholine, and radiation stressors on lake and round
whitefish embryogenesis.
  To examine the effects of fluctuating incubation temperatures, lake and round
whitefish were reared at constant temperatures, with seasonal temperature
declines/inclines, transient temperature spikes, or seasonal temperature changes combined
with temperature spikes. Round whitefish embryos had significantly higher mortality
when reared at 8°C compared to lake whitefish, and seasonal temperature changes
impacted development rate, growth, and hatch dynamics for both species. Temperature
spikes had relatively little effect on development.
 The effects on embryonic development of chronic morpholine and low-dose
radiation exposures were examined in round whitefish to compare with existing data in
lake whitefish. Round whitefish embryos were more impacted by morpholine than lake
whitefish (larger effects on growth and mortality at relatively lower concentrations) and
v
less impacted by low-dose radiation (little effect on growth or hatch dynamics). Post
hatch, round whitefish embryos reared at 8°C, with rapid seasonal inclines, or with 500
mg L-1 morpholine had elevated mortality. All irradiated embryos had decreased mortality
post-hatch compared to non-irradiated embryos. Thus, embryonic exposure to all stressors
examined appears to alter post-hatch survival.
This thesis better defines the effects of fluctuating incubation temperatures,
chronic morpholine, and chronic radiation exposures on the embryonic development of
lake and round whitefish. It also suggests that embryonic incubation conditions are
important beyond hatching.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
Lake and round whitefish are cold-adapted freshwater species. Both species
play important ecological roles, with lake whitefish generally perceived as more
economically and culturally important. Many studies have detailed lake whitefish
embryonic development under constant stressors (e.g. temperature) but there are
relatively few studies on round whitefish embryonic development. Both species
experience seasonal temperature fluctuations in nature and may experience
additional anthropogenic temperature, chemical, and radiation stress due to
discharge from once-through cooling processes at thermal power plants, which may
contain low levels of morpholine and radiation. Our study suggests that round
whitefish embryos are more sensitive to elevated temperature and morpholine
levels, but less impacted by chronic low-dose irradiation relative to lake whitefish
embryos. The growth and development of both species are significantly affected by
seasonal temperature changes.


contributor:
Datars, W.R.
Physics

abstract: Title: Observations of the de Haas-van Alpen Effect in Arsenic, Author: John Vanderkooy, Location: Thode

abstract:
Semimetallic arsenic has been studied by magneto-resistance
methods and measurement of the de Haas-van Alphen effect using torque and magneto-thermal measurements. Several modifications have been made in the conventional torque techniques. An important cause of nonlinear effects in the torque experiments is presented and compared to other mechanisms for nonlinearities. The Fermi surface of arsenic as determined experimentally is shown to be in good agreement with recent
theoretical calculations which were partially guided by the experiments.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


contributor:
Davies, J.A.
Geography

abstract: Title: An Analysis of Air-Pollution Trends in Southern Ontario, Author; Eric Unrau, Location: Thode

abstract: <p>Concentrations of seven pollutants, carbon monoxide, nitric oxide, nitrogen dioxide, total nitrogen oxides, ozone, particulates, and sulphur dioxide are evaluated to identify trends since 1971 when the Canadian Clean Air Act became law. Data is analyzed from monitoring stations located in four cities in Southern Ontario. Decreases are observed in the nitrogen oxides, carbon monoxide and sulphur dioxide giving some indication of the effects of the act.</p.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: Nurses' Experiences of Patients' Deaths in Complex Continuing Care: An Interpretive Description

contributor:
Kaasalainen, Sharon
Nursing

subject:
patient death
support
nurses' experiences
continuing care
chronic care
end-of-life care

abstract:
Complex continuing care (CCC) is a healthcare setting where many patients die. Previous research has demonstrated that patient deaths can be meaningful and challenging for nurses. However, little knowledge exists regarding how the unique features of CCC influence nurses’ experiences in managing patient deaths. The objective of this study was to explore nurses’ experiences when patients die and their perceptions of support surrounding these experiences.
Using interpretive description methodology, 13 memorable patient death experiences were explored in semi-structured interviews with licensed nurses (n=12) and nursing leaders (n=1). Criterion and theoretical purposeful sampling were used to develop a rich understanding of nurses’ experiences when patients die. Concurrent data collection and analysis uncovered five key intersubjective themes which described nurses’ experiences with individual deaths and how nurses’ experiences change overtime which included: (a) Professionally experiencing patients’ deaths: 'Engaging your left brain;’ (b) Personally experiencing patients’ deaths: ‘I’m a human being too;’ (c) Seeking resolution in the experience: ‘It was a good resolution;’ (d) Integrating professional and personal experiences: ‘Applying what you learn in your nursing life into your personal life and vice versa,’ and; (e) Supporting One Another in a Culture of Acknowledging Patients’ Deaths and Nurses’ Experiences: ‘They expect us just to take it, the nursing profession is like that.’ These findings suggest that nurses need support to facilitate the interpersonal and intrapersonal aspects of their experiences with patient death. This support should be grounded in a unit culture which openly accepts patient death and acknowledges nurses’ experience. Just-in-time education, peer mentorship and targeted support may further facilitate nurses’ ability to find resolution when patients die and support their on-going journey towards integrating death experiences in their lives and practice.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Complex continuing care (CCC) is a healthcare setting where many people die. Patient deaths can be difficult and sad for nurses. The goal of this study was to learn more about nurses’ experiences when patients die in CCC. Nurses were asked to share memories of when patients died in CCC. This study found that patient deaths influence nurses personally and professionally. Nurses with fewer death experiences were uncomfortable caring for dying patients. Feeling understood and having their experience recognized were meaningful ways that nurses wanted to be supported. It was very important to nurses that the deceased person was respected and nurses worried about patients’ family members. This research shows that nurses with fewer death experiences would benefit from unique education and support. It is important to support nurses by creating a culture that acknowledges death in CCC and nurses’ responses to patients’ deaths.


title: Modeling and Parameter Estimation in Biological Applications

contributor:
Mhaskar, Prashant
Chemical Engineering

subject:
Cell culture
Modeling
Parameter estimation

abstract: Biological systems, processes, and applications present modeling challenges in the form of system complexity, limited steady-state availability, and limited measurements. One primary issue is the lack of well-estimated parameters. This thesis presents two contributions in the area of modeling and parameter estimation for these kinds of biological processes. The primary contribution is the development of an adaptive parameter estimation process that includes parameter selection, evaluation, and estimation, applied along with modeling of cell growth in culture. The second contribution shows the importance of parameter estimation for evaluation of experiment and process design.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Purification of fuel grade Dimethyl Ether in a ready-to-assemble plant

contributor:
Adams, Thomas A.
Chemical Engineering

subject: dimethyl ether, process intensification, dividing wall column, semicontinuous distillation, Aspen Plus Dynamics, computer simulation

abstract:
Due to the remote and dispersed nature of Alberta’s oil wells, it is not economical for the energy industry to capture all of the solution gas produced and as a result, the gas is being flared and vented in significant amounts. The objective of this research is to aid in the conversion of solution gas into dimethyl ether (DME) in a remote location by designing a distillation column that purifies DME and its reaction by-products, carbon dioxide, methanol and water.
In order to develop an implementable solution, the distillation equipment must fit inside of a 40-foot shipping container to be transported to remote locations. Given the size constraint of the system, process intensification is the best strategy to efficiently separate the mixture. Several process intensification distillation techniques are explored, including semicontinuous distillation, the dividing wall column (DWC) and a novel semicontinuous dividing wall column (S-DWC).
The traditional semicontinuous distillation column purifies DME to fuel grade purity, however the other components are not separated to a high enough grade given the height constrain of the system. The DWC and S-DWC both purify DME to its desired purity along with producing high purity waste streams. The S-DWC purifies the reaction intermediate methanol to a grade slightly higher than the DWC and is pure enough to recycle back to the reactor.
An economic comparison is made between the three systems. While the DWC is a cheaper method of producing DME, the trade-off is the purity of the methanol produced.
Overall, this research shows that it is possible to purify DME and its reaction by-products in a 40-foot distillation column at a cost that is competitive with Diesel.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: TECHNO-ECONOMIC COMPARISON OF ACETONE-BUTANOL-ETHANOL FERMENTATION USING VARIOUS EXTRACTANTS

contributor:
Adams II, Thomas
Chemical Engineering

subject:
Acetone-butanol-ethanol fermentation
Extractant
Techno-economic analysis

abstract: This work seeks to compare various Acetone-Butanol-Ethanol (ABE) fermentation extraction chemicals on an economic and environmental basis. The chemicals considered are: decane, a decane/oleyl alcohol blend, decanol, a decanol/oleyl alcohol blend, 2-ethyl-hexanol, hexanol, mesitylene, and oleyl alcohol. To facilitate comparison a pure-distillation base case was also considered. The aforementioned extractants are a mix of both toxic and non-toxic extractants. Non-toxic extractants can be used directly in fermentation reactors, improving overall fermentation yield by removal of toxic butanol. The extractants were modelled in Aspen Plus V8.8 and separation trains were designed to take advantage of extractant properties. The separation section of the plant was then integrated with upstream and downstream units to determine the Minimum Butanol Selling Prices (MBSP) for second generation extractive ABE fermentation. Upstream processes include biomass (switchgrass) solids processing, biomass pre-treatment/saccharification and fermentation while downstream processes include utility generation and wastewater treatment. The cost of CO2 equivalent emissions avoided (CCA) was used as a metric to compare environmental impact of each process as compared to gasoline. The economic best and environmental best extractant is shown to be 2-ethyl-hexanol with a MBSP of $1.58/L and a CCA of $471.57/tonne CO2 equivalent emissions avoided. Wastewater treatment, which is often ignored in other works, was found to makeup over 30% of total installed capital cost for all extractants.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Interactions and dynamics of the type IV pilus alignment subcomplex proteins, PilN and PilO

contributor:
Burrows, Lori
Biochemistry and Biomedical Sciences

subject:
Type IV Pilus System
Pseudomonas aeruginosa

abstract: Type IV pili (T4P) are long, thin, flexible surface appendages used by various bacteria for surface adhesion, cell-cell aggregation, DNA uptake, biofilm formation and motility. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen, and uses T4P as a key virulence factor to infect immunocompromised individuals. Four subcomplexes make up a functional T4P system in P. aeruginosa and the role of the alignment subcomplex is to physically connect the outer membrane pore with the inner membrane motor, allowing for efficient extrusion of the pilus fibre from the cell. Two alignment subcomplex proteins, PilN and PilO, form heterodimers and are required for proper function of the system. These proteins may be able to transduce signals between various T4P components to indicate extension and/or retraction of the pilus fibre. This thesis focused on characterization of the interaction interfaces between PilN and PilO, and on understanding the dynamics required for proper function of the system. We show that although PilN and PilO make extensive interaction contacts throughout their lengths, single point substitutions at key residues can successfully disrupt the function of the T4P system. Crosslinking PilN and PilO as homo- or heterodimers can disrupt motility and surface piliation, indicating that interfaces between these proteins must be dynamic to allow proper T4P function. A high resolution X-ray crystal structure of PilO was solved and exhibits new structural features previously unidentified. This work furthers our understanding of the structures and regions of interaction between PilN and PilO, as well as defining a role for these proteins in extension and retraction.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Pseudomonas aeruginosa is an opportunistic bacterium, able to infect individuals with weakened immune systems. It attaches to and moves along surfaces using long, thin, sticky, retractable fibres known as type IV pili. Similar to a grappling gun, a functional type IV pilus system requires four subcomplexes working in unison to allow for the extension, adherence, and retraction of pilus fibres, which pulls the cell forward towards the point of attachment. Two key proteins, PilN and PilO, are bound to each other and allow for efficient extension and retraction of the pilus fibre. This study focused on characterization of the interactions of PilN and PilO, and on understanding whether dynamic rearrangements of the interfaces between these proteins is required for proper function of the system. We show that although these proteins have extensive interaction interfaces, single residue substitutions in either of them can disrupt the ability of the bacteria to properly extend and/or retract their pili. This work furthers our understanding of the structures and regions of interaction between PilN and PilO, providing information that might allow disruption of these interfaces to block bacterial attachment or motility, both of which are important for infection.


title: Regulation of a muralytic resuscitation-promoting factor in Streptomyces coelicolor

contributor:
Elliot, Marie
Biology

abstract: To survive inhospitable conditions, bacteria can form fortified stress-resistant cells that are unable to grow and have little to no detectable metabolic activity. Upon detecting improved environmental conditions, these cells can reactivate metabolism and resume growth. A common aspect of establishing and exiting dormancy involves the extensive remodeling of the bacterial cell wall. In the actinobacteria, the ‘resuscitation-promoting factors’ (Rpfs) orchestrate the exit from dormancy through their muralytic activities. The expression and activity of muralytic enzymes are tightly regulated. Excessive activity could weaken the cell wall, leading to lysis, while insufficient activity, in the case of the Rpfs, could compromise resuscitation from a dormant state. rpf genes are regulated at the level of transcription initiation; however, these genes are likely also regulated post-transcriptionally and post-translationally. For example, in Streptomyces coelicolor, rpfA is associated with several regulatory RNAs: a riboswitch motif is located within the 5′ untranslated region, while a small RNA-encoding gene is located immediately downstream of the rpfA stop codon. In this work, we probed multi-level rpfA regulation in S. coelicolor, placing a particular emphasis on RNA-based control mechanisms acting post-transcriptionally. We found that rpfA was regulated at many levels: transcription initiation, transcript elongation and protein stability. We also discovered that rpfA served as a regulatory hub, receiving input from three second messengers with known functions in dormancy and/or resuscitation. During the course of this work, we also uncovered a novel riboswitch regulatory mechanism and identified previously uncharacterized activity determinants for this riboswitch class. Finally, we showed that the downstream-encoded small RNA impacted the expression of genes involved in microaerobic metabolism and, through its predicted regulation of rpfA expression, may coordinate cell wall remodeling and dormancy/resuscitation with the hypoxic response. This work dramatically expands our understanding of rpf gene regulation and actinobacterial resuscitation.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: THE ROLE OF AMPLITUDE ENVELOPE IN AUDIO-VISUAL PERCEPTION:  TESTING THE EFFECT OF AMPLITUDE ENVELOPE IN SPATIAL VENTRILOQUISM

contributor:
Schutz, Michael
Psychology

subject: audio-visual integration, amplitude envelope

abstract: The world is filled with richly diverse sounds which we are able to perceptually distinguish using a variety of properties.  One of these properties is the amplitude envelope, or the intensity of a sound over time.  While it is common in the real world for sounds to have time-varying amplitude envelopes, the majority of sounds used in perceptual research have time-invariant or unspecified amplitude envelopes.  The aim of the present thesis is twofold.  Because many of the studies using time-invariant or undefined envelopes make use of very short sounds (below 100 msec), the first experiment aimed to determine the duration required for discriminating among three different envelopes: flat (invariant), ramped (increasing in intensity over time), and damped (decreasing in intensity over time).  In Experiment 1, participants took part in a 2-alternative forced choice, psychophysical staircase paradigm in which they indicated which of two envelopes they thought they were listening to.  Results showed that, when telling ramped tones apart from either flat or damped tones, participants showed discrimination thresholds below 50 msec, while they had thresholds of approximately 75-80 msec when differentiating flat from damped tones.  Because amplitude envelope has been shown to impact audiovisual integration and the perceptual system is sensitive to interaural envelope differences when localizing sounds, the second experiment aimed to determine whether amplitude envelope could modulate the visual bias present in spatial ventriloquism, an audiovisual illusion where the perceived location of a sound is influenced by the location of a visual stimulus. In Experiment 2, participants performed a psychophysical staircase task which measured their accuracy in localizing sounds with flat and damped envelopes, with or without a simultaneous flash on the screen in front of them.  Results showed that, at durations above the envelope discrimination thresholds found in Experiment 1 (83 msec), there was no visual bias on perceived location of the sound, while the bias was present at a duration below this threshold (16 msec).  Together, these results add to the mounting evidence suggesting that amplitude envelope has profound and varied effects on our perception of sounds, and is an important property to consider when designing experiments.

abstract: Thesis

abstract: Master of Science (MSc)


title: Cyclic Fatigue Behavior of Friction Stir Welded AZ-Series Magnesium Alloys

contributor:
Niewczas, Marek
Materials Science and Engineering

abstract:
Fully reversed stress controlled cyclic fatigue testing in ambient air was conducted on
friction stir welded magnesium AZ31 and AZ61 to magnesium AZ80 specimens to study
the fatigue behavior and properties of the weld and to grasp an understanding of the rela-
tionship between the material substructure and fatigue life. The resulting stress amplitude
vs. cycles to failure (S-N) curves show an increase in fatigue life with a decrease in stress
amplitude. For the AZ80/AZ31 weld, a sharp bend in the fatigue data was observed with an
endurance limit of 70 MPa. A sharp bend was also observed in the AZ80/AZ61 weld which
had an endurance limit of 90 MPa. Almost all the specimens fractured at the interface be-
tween the heat-affected zone of the weld and the AZ80 base material for both dissimilar
welds. SEM fracture surface observations from the AZ80/AZ31 weld show crack initiation
occurring from the surface and crack propagation through the material for the high and
moderate stress amplitudes. The fracture surfaces were neither true brittle nor true ductile,
instead, they were a combination of the both with evidence of secondary angled cracking.
The fracture surfaces also exhibited macroscopic and microscopic features unique to fa-
tigue failure, which includes fatigue striations and beach marks. Analysis of the material
dislocation substructure was conducted using TEM microscopy for the AZ80/AZ31 speci-
mens tested at a high stress, moderate stress, and the endurance limit stress. A difference in
the dislocation substructures and densities is observed from the different specimens which
can be related to the stress amplitude applied. X-ray diffraction was also conducted on
specimens tested at a high stress, moderate stress, and the endurance limit stress, as well
as a specimen that was undeformed. The pole figures show a strong initial basal texture
for the undeformed specimen that becomes rotated off the tensile axis as the specimens are
subjected to increasing fatigue damage. The pole figures for the moderate stress and the
endurance limit stress show a basal texture rotation of approximately 85 degrees.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Interpretation of Pronouns in Proxy Counterfactuals

contributor:
Kučerová, Ivona
Cognitive Science of Language

subject: semantics pronouns

abstract: This thesis focuses on the interpretation of pronouns, in particular as subjects of the consequent clauses of counterfactual conditionals. More specifically, the constructions under consideration have been termed proxy counterfactuals. They are characterized as identifying two individual-denoting expressions in such a way that a new, composite individual is hypothesized. This hypothetical individual shares certain properties with both of the individuals denoted in the antecedent clause. Pronouns in the consequent clause referring back to this composite individual exhibit unusual binding properties. Their morpho-syntactic realization is uniquely determined by the subject of the antecedent clause, while their semantic interpretation is bound to both individuals denoted in the antecedent clause. I will examine cases involving first and second person pronouns, and adopt a previously put forth analysis which treats them as rigidly designating (Thomas, 2009). Cases involving the third person will require additional attention. The proposed analysis makes use of the Formal Link condition on e-type anaphora (Kadmon, 1987; Heim, 1990) in combination with a constraint on the use of gender features (Yanovich, 2012) in order to account for the observed constraints.

abstract: Thesis

abstract: Master of Science (MSc)


title: Development of Intensity-Duration-Frequency Curves Using Local and Regional Scale Methods

contributor:
Coulibaly, Paulin
Earth Sciences

subject: Intensity-Duration-Frequency flooding

abstract:
Traditionally civil infrastructure designs were rendered using rainfall data from dated historical records. However, recent studies have shown that the magnitude and intensity of historical precipitation events do not exhibit the extreme nature of precipitation events that are projected to occur in the future. Increasing extreme rainfall trends have already been documented in Canada. Therefore there are growing concerns that the aging infrastructure in southern Ontario will be unable to function effectively and as a result the frequency of floods is expected to increase. Updating intensity-duration-frequency (IDF) curves to account for extreme precipitation events is vital to ensure that the consequences of floods are mitigated. This study first reviewed the most robust techniques for updating IDF curves, and applied a select set of approaches to create IDF curves for stations within southern Ontario.
	Three robust techniques – the at-site method, the regional frequency analysis method, and a future IDF curve development technique – were compared with one another to determine which technique was most suitable for updating IDF curves in southern Ontario. Results showed that the difference between the at-site method and the regional frequency analysis method was marginal for short return periods, however for larger return periods larger differences were observed. Future IDF statistic results showed that for the 2050s there were minor differences in the increases in rainfall intensities when comparing with the at-site and the regional frequency analysis method. For the 2100s there were larger increases in rainfall intensities compared to the at-site and the regional frequency analysis method, especially for larger return periods. These results suggest that it is worthwhile for regions within southern Ontario to update their IDF curves using the future IDF curve technique, however it is recommended that additional climate models, emission scenarios and downscaling techniques involved in future IDF curve construction are explored.

abstract: Thesis

abstract: Master of Science (MSc)


contributor:
Gillespie, R.J.
Chemistry

abstract: Title: Formation of Polyatomic Cations of Tellurium, Sulfur and Antimony in Flourosulfuric Acid, Author: Om C. Vaidya, Location: Thode

abstract:
Polyatomic cations of tellurium, sulfur and antimony have been studied in HS03F. Tellurium metal can be oxidised with S206F2 in HS03F to the (+1) oxidation state. The cryoscopic measurements in HS03F suggest that the cation is not Te2^2+ but a higher polymer. Sulfur can be oxidised to the (+1/8), (+1/4) and (+1/2) oxidation states in acidic solvents. The cations S16^2+ and S8^2+ have been identified in the solutions from cryoscopic conductivity measurements and UV-visible absorption spectroscopy.

UV-visible absorption spectra, cryoscopy and conductivity measurements show that antimony metal is oxidised by HS03F to the (+1) and (+3) oxidation states. The compounds of antimony in the (+1) oxidation states have been prepared. Sb(I) reduces HS03F to sulfur cations and elemental sulfur. No evidence has been obtained for an oxidation state of antimony lower than (+1).

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Stories Statistics Tell

title: An Ethnographer’s Exploration of Homeless Shelters’ Performance Measurements

contributor:
Baker Collins, Stephanie
Social Work

subject:
institutional ethnography
homeless shelter
performance measurements

abstract: Utilizing institutional ethnography and a critical analysis, this thesis explicates the textually-mediated process and ruling relations of performance measurement data collection in emergency homeless shelters. The thesis aimed to answer the query of whether the performance measurements collected by a set of programs, within a non-profit social service, adequately captured the full contribution of the work the staff did at their respective emergency shelter. Using literature, that has captured the experiences and insights of frontline workers who feel their work is inadequately captured, as a launch pad, this study spoke to informants who are directly involved in the creation of data collection tools and the reporting of the output and outcome performance measurements. How were these tools created? Who influences the development of the tools? Are some performance indicators (i.e. outputs, quality assurance, outcomes) measured more frequently or thoroughly than others? What are some of the barriers to measuring performance indicators? The study is based on five one-to-one semi-structured interviews, with informants working for a non-profit social service in Southern Ontario, and an analysis of the data collection tools used to compile performance measurements. The purpose of this research is to help social services, especially those that focus on addressing homelessness, improve the tools used to collect statistics on service so as to better articulate the breadth of work done by these services.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: USING DNA-BASED METHODS TO DETECT AND IDENTIFY FECAL CONTAMINATION SOURCE IN GROUNDWATER TO AUGMENT CULTURE-BASED DETECTION OF FECAL POLLUTION

contributor:
Schellhorn, Herbert
Biology

subject: Metagenomics, Microbial Source Tracking, Water Quality, Bioinformatics

abstract: Residents in rural communities across Canada rely on groundwater as their main drinking water source, but the private maintenance of this source may increase the risk of fecal contamination caused by human or animal wastes. Wainfleet, a rural Ontario community, has been under an active boil water advisory for the past decade. The last study to assess groundwater quality, performed in 2007, determined that half of the 586 groundwater wells contained exceedances in total fecal coliform and E. coli counts. A critical examination of fecal contamination levels and its sources is not only necessary for maintaining public health in the township, but is also an opportunity to examine the robustness of culture-independent methods for quantifying and sourcing fecal contamination in groundwater environments across Canada. For this project, culture-based and culture-independent methods were utilized to quantify and source any fecal contaminants in Wainfleet’s groundwater. Culture counts of fecal indicator bacteria (FIB) suggested that some of the groundwater wells were receiving more fecal contamination than others, as expected based on a previous study that was conducted 10 years prior. The groundwater wells with higher E. coli counts also had higher read counts of microbes like Campylobacterales which could come from septic tanks and higher concentrations of oxidized nitrogen which can also indicate human-based fecal contamination. Finally, fecal contamination in groundwater wells with E. coli tested positive for the human Bacteroidales marker. Taken together, this study shows that fecal contamination pervades groundwater wells across the boil water advisory zone, much of which originates from leaking septic tanks and poorly-constructed groundwater wells. In this study, we have shown that a suite of protocols, from physiochemical quantification to targeted sequencing and qPCR, can be used to complement culture-based assays in quantifying and pinpointing fecal contamination in groundwater sources.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Boil water advisories are enacted when fecal contamination levels exceed provincial limits. Standard methods for quantifying fecal contamination use the culture-based detection of fecal indicator bacteria. Sequencing the 16S rRNA gene and amplifying Bacteroidales markers can also be used to identify novel fecal markers and quantify host-specific contaminants in source waters. Using culture and genetic-based methods determined that groundwater wells across Wainfleet, a Niagara township with the longest active boil water advisory in Canada, contain septic tank microbes and are primarily contaminated by leaking septic tanks. Genetic-based assays can complement culture-based detection of fecal bacteria in groundwater sources across Canada.


contributor:
Smeltzer, W.W.
Metallurgy

abstract: Title: High Temperature Oxidation Kinetics of a Zr-21/2 w/o Nb Alloy, Author: Vincent F. Urbanic, Location: Thode

abstract:
An investigation is reported on the oxidation kinetics of a Zr-21/2 w/o
Nb alloy in the temperature range 650° - 1000°C in pure oxygen atmospheres. Weight gain data is presented for rectangular plate specimens in the range 650° - 991°C. The kinetics were determined continuously using thermogravimetric techniques and may be represented by a parabolic relationship followed by essentially linear kinetics over the range 650° - 885°C, while over the range 937°- 991°C, parabolic kinetics is followed by a breakaway transition to an increasing reaction rate. In the low temperature range the parabolic rate constant has been calculated to be k = 20.8 exp (-38026/RT) and in the high temperature range kp = 0.22 exp (-30054/RT).

The latter part of the investigation was focused on the oxidation of Zr-21/2 w/o Nb at 1000°C in pure oxygen for periods extending to 23 hours. The morphological development of the oxide scale and metal substrate during parabolic oxidation was investigated and is supported by kinetic, X-ray, electron micro-probe and metallographic observations. Spherical specimens were used to minimize edge effects and hence extend the period of parabolic behaviour. The observed microstructures are discussed with reference to the
Zr-Nb-0 phase diagram.

A qualitative discussion pertaining to observations related to the breakaway phenomenon is also presented.

abstract: Thesis

abstract: Master of Science (MS)


contributor:
Papageorgiou, Yorgos
Geography

abstract: Title: The Recent Evolution of Canada's Metropolitan-Non-Metropolitan Ethnic Composition, Author: Rossane C.Valeri, Location: Thode

abstract:
The purpose of the research is to observe and describe recent evolutionary trends in Canada's metropolitan and nonmetropolitan ethnic composition by comparing census years 1971 and 1981. To identify salient spatial and temporal trends, three types of analyses were used: the index of ethnic diversity, the chi square test, and cluster analysis. These analyses employed ethnic origin data taken from the 1971 and 1981 censuses. Twenty-five CMAs were used and nine ethnic groupings. The non-metropolitan components were aggregated provincially. The research shows that variations in conditions over time and space affect ethnic composition to some extent. While the degree of diveisity may be
similar, the internal ethnic composition may be very diffeirent. It will also invalidate the claim that the size of cities is correlated with their index of ethnic diversity. In addition, a metropolitan and nonmetropolitan
regionalization are produced which identify four main ethnic regions in Canada based on similarities in ethnic distributions. Factors such as historical settlement, socio-economic opportunities, demographic
characteristics, cultural atmosphere, internal migration and immigration policy are offered as determinants of ethnic composition and change.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: DUAL ENTROPY MULTI-OBJECTIVE OPTIMIZATION APPLICATION TO HYDROMETRIC NETWORK DESIGN

contributor:
Coulibaly, Paulin
Civil Engineering

subject:
entropy
hydrometric network
multi-objective optimization
network design
hydrology

abstract: Water resources managers rely on information collected by hydrometric networks without a quantitative way to assess their efficiency, and most Canadian water monitoring networks still do not meet the minimum density requirements. There is also no established way to quantify the importance of each existing station in a hydrometric network. This research examines the properties of Combined Regionalization Dual Entropy Multi-Objective Optimization (CR-DEMO), a robust network design technique which combines the merits of information theory and multi-objective optimization. Another information theory based method called transinformation (TI) which can rank the contribution of unique information from each specific hydrometric station in the network is tested for use with CR-DEMO. When used in conjunction, these methods can not only provide an objective measure of network efficiency and the relative importance of each station, but also allow the user to make recommendations to improve existing hydrometric networks across Canada. The Ottawa River Basin, a major Canadian watershed in Ontario and Quebec, was selected for analysis. Various regionalization methods which could be used in CR-DEMO such as distance weighting and a rainfall runoff model were compared in a leave one out cross validation. The effect of removing stations with regulated and unnatural flow regimes from the regionalization process is also tested. The analysis is repeated on a smaller tributary of the Ottawa River Basin, the Madawaska Watershed, to examine scale effects in TI analysis and CR-DEMO application. In this study, tests were conducted to determine whether to include stations outside of the river basin in order to provide more context to the basin boundaries. It was found that the TI analysis complemented CR-DEMO well and it provided a detailed station ranking which was supported by CR-DEMO results. The inverse distance weighting drainage area ratio method was found to provide more accurate regionalization results compared to the rainfall-runoff model, and was thus chosen for CR-DEMO. Regionalization was shown to be more accurate when the regulated basins were omitted using leave one out cross validation. It was discovered that CR-DEMO is sensitive to scaling because some sub-basins which are relatively “well-equipped” compared to others in dire conditions may be penalized. The TI analysis was not as sensitive to scaling. Including stations outside of the Ottawa River Basin improved the information density and regionalization accuracy in the Madawaska Watershed because they provided context to sparse areas. Finally, Pareto optimal network solutions for both the Ottawa River Basin and the Madawaska Watershed were presented and analyzed. A number of optimal networks are proposed for each watershed along with “hot-spots” where new stations should be added whatever the end users’ choice of network.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Moral Ignorance and Blameworthiness in Aristotle's Nicomachean Ethics

contributor:
Johnstone, Mark
Philosophy

subject:
Philosophy
Ancient Philosophy
Ethics
Moral Psychology
Aristotle

abstract: In this thesis, I identify and engage an orthodox view in Aristotelian scholarship. Many scholars maintain that Aristotle, in the third book of his Nicomachean Ethics, claims that we should always blame people who act badly with ignorance of what is moral. This view, which I label the “common view” is widespread and unquestioned in the literature. I disagree with the orthodox view, and maintain that we can read Aristotle as not always holding people who act badly in ignorance of what is moral as blameworthy. There are three essential steps in my argument. First, I show that it is not certain that Aristotle commits himself to the common view in the passages usually cited as evidence for the view. I review the evidence in favor of the common view, and argue that other interpretations of Aristotle are equally compatible with his text. Second, I argue that there is textual evidence elsewhere in the Nicomachean Ethics which is contrary to the common view. Thirdly and finally, I suggest that an alternate reading – on which Aristotle allows for pardon in some cases where people act badly in ignorance of what is moral – chimes well with other portions of his ethics, and with scholarly literature: I take two such cases, moral education and ethical deliberation. Given the evidence against the common view, and the evidence in favor of an alternate reading, I suggest that the orthodox view should be abandoned by scholars.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: In this thesis I identify and engage an orthodox view in Aristotelian scholarship. Many scholars maintain that Aristotle, in the third book of his Nicomachean Ethics, claims that we should always blame people who act badly with ignorance of what is moral. This view, which I label the “common view” is widespread and unquestioned by scholars. I disagree with this reading of Aristotle. I do not think that Aristotle commits himself to this view in his writings. Moreover, I argue that the common view is a bad fit with other passages from the Nicomachean Ethics. If the common view is false, as I claim, it is important for us to formulate an alternate reading of Aristotle’s comments. I proffer one such reading, a reading on which people are not always worthy of blame when they act badly in ignorance of what is moral.


title: The Impact of Precarious Employment on Social Work Skill Engagement and Career Satisfaction for Women

subject:
social work
precarious employment

abstract:
A significant amount of literature discusses the changing nature of the social service sector and social work due to neoliberalism.  The literature review discusses these neoliberal changes in connection with precarious employment and its’ impact on social work skills, career satisfaction and resistance. A small qualitative study was done, from a feminist and critical perspective, to understand how precarious employment impacts the particular social work skills of: relationship building, advocacy and reflexivity. Also, this study aimed to learn whether or not social workers engaged in activities and discussions to address precarious employment in their organizations and whether the impact of precarious employment on social work skills affected career satisfaction.

     This data for this study was collected through 5 semi-structured interviews. Participants held a Bachelors in Social work degree and or a Master’s degree with a minimum of one years work experience. Their length of practice ranged from 1 to 14 years, and came from a variety of service sectors.

     Through the stories participants shared it became evident that precarious employment had a negative impact on participants’ ability to engage in relationship building, reflexivity and advocacy. Also, precarious employment negatively impacted career satisfaction. It also became evident that resistance to precarious employment became difficult; however, participants still resisted through the use of unions and smaller acts of resistance.  Findings highlight the need for the social work profession and social work organizations to challenge the neoliberal norm permanent precarious employment and to advocate for standard employment relationships with social workers.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Methodological considerations on the spatial and temporal analysis of violent crime patterns and the identification of social and environmental correlates of crime

contributor:
Páez, Antonio
Geography and Earth Sciences

abstract: Violent crime which is referred to as crime against persons has been recognized as the most serious species of crime. Violent crime imposes monetary costs, psychological costs, and social stability disruption. Incarceration strategies used in several societies have been inefficient in deterring, incapacitating, and rehabilitating offenders of violent crime. Additional approaches to preventing and reducing violent crime are needed. This dissertation aims to address three objectives. First, empirically investigate the temporal stability of socio-economic covariates of violent crime. Second, investigate the persistence of violent crime hot spots over time, and the socio-economic factors that correlate with said persistence. Third, develop a Google Street View-based environmental audit approach to quickly and systematically collect environmental data, and explore the role of physical features of built environment in inducing and deterring violent crime. The results of model parameter analysis indicate that it is unnecessary to average crime over multiple years if model parameters are stable across years. The results of hot spots persistence analysis suggest that a combination of social disorganization theory and routine activity theory provides an applicable framework for understanding the temporal dimension of violent crime hot spots. By identifying the factors that contribute to the persistence of hot spots of crime, insights gained from the results can help to inform focused crime prevention practices. The results obtained from Poisson regression with spatial filtering and Google Street View-based environmental audit provide a series of environmental correlates of violent crime, and provide both theoretical and practical implications for several theories of crime and crime prevention efforts.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Inflammation and Physical Frailty in Women with Knee Osteoarthritis

contributor:
Maly, Monica
Rehabilitation Science

subject:
Frailty
Inflammatory cytokines
Knee Osteoarthritis
Arthritis
Interleukin-6
Interleukin-10
Tumor Necrosis Alpha
C reactive protein

abstract:
Background:
Knee osteoarthritis (OA) is the most common form of arthritis in older adults.  Knee OA is associated with limitations in physical function.  Functional limitations are also associated with another geriatric condition, frailty.  Frailty is characterized by reduced strength, endurance and physiological function.

Purpose:
The primary purpose of this study is to determine if there is a difference in radiographic or symptomatic knee OA severity between non-frail and pre-frail women with knee OA.  Secondary objectives include: a) the relationship between radiographic and symptomatic OA severity with serum inflammatory cytokines, and b) if there is a difference in inflammatory cytokines between non-frail and pre-frail women with knee OA.

Methods:
We included 21 community-dwelling women with knee OA.  Frailty was assessed using the Fried Frailty Phenotype. Knee OA severity was characterized by the Kellgren and Lawrence (KL) score and the Knee Injury and Osteoarthritis Outcome Questionnaire (KOOS).  Inflammatory cytokines included serum interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis alpha (TNF α) and C reactive protein (CRP).

Results:
Data from 20 participants (66.1 [9.6] years, BMI 29.7 [4.9] kg/m2, non-frail=55%; pre-frail=45%) were analyzed.  Radiographic severity was not different between frailty groups (p= 0.11).  There was no difference in symptomatic knee OA severity, measured using the KOOS subscales, between frailty groups (p>0.17).  Radiographic OA severity and inflammatory markers were not associated (p>0.30).  There was a negative relationship between TNF α and self-reported pain (r=0.26), no relationships between inflammatory cytokines with any other KOOS sub-scales.  Lastly, there was no difference in any inflammatory cytokines between non-frail and pre-frail groups.

Conclusion:
Despite the relatively young age, nearly 50% of our participants were pre-frail.  Pre-frailty was unrelated to the severity of the knee OA, or inflammatory cytokines. TNF α may be involved in the experience of pain in these women.  While it appears women with knee OA frequently demonstrate pre-frail status, more work is necessary to examine the link between these diseases.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Arthritis is a chronic disease that has a debilitating effect on the lives of more than 4.6 million Canadians.  In 2015, the cumulative economic burden of osteoarthritis was 195.2 billion dollars and is expected to increase significantly in the next two years.  Knee osteoarthritis is the most common form of arthritis in older adults.  Knee osteoarthritis is associated with increased pain, decreased physical function and decreased quality of life (QOL).  In vulnerable older adults increased exhaustion, decreased physical function and muscle loss can increase the risk of developing frailty.  Frail older adults are at higher risk of adverse health outcomes such as falls, hospitalization and death.  Previous research has shown that older adults with knee OA are at higher risk of developing frailty however, it is not understood what underlying mechanisms increase this risk.  This thesis provides fundamental information aimed at understanding potential mechanisms associated with knee osteoarthritis and frailty in women.  Our study found that despite their relatively young age, nearly half of the women with knee OA are pre-frail. This data shows that inflammatory cytokines in particular, tumor necrosis factor alpha is related to symptomatic knee osteoarthritis severity in particular, self-reported pain. Overall, early detection of frailty is important when managing this condition. These data suggest that chronic knee pain associated with OA may be a useful trigger for early assessments of frailty in women.


title: Solar powered motorized blinds:  A case study on using energy harvesting to power internet of things applications

contributor:
Preston, John
Engineering Physics

subject:
Home Automation
Internet of Things
Energy Harvesting
Window attenuation
Design
Prototype
Motorized Window Blind
Powerflow
Model
Simulation
Solar Power

abstract:
Smart devices capable of harvesting their own energy have advantages over their wired or battery-powered alternatives including improved portability, simplified installation, and reduced maintenance and operating costs. This thesis studies energy harvesting technology through a case study of a solar-powered motorized window shade. An analytical and experimental evaluation of window attenuation found that windows reduced the ability of solar cells to produce photocurrent by 30%-70%. This still allows significant potential to power small electronics so a prototype motorized window blind was designed and assembled. The solar array was mounted to the roller blind's bottom rail and power is conveyed to the control electronics and motor in the unit’s top cylinder through wires embedded in the shade’s fabric. A simple battery system was implemented to ensure the prototype could remain powered in the absence of light.

Various forms of powerflow in the prototype were evaluated. Experimental evaluation of joule heating within the conductive textile indicates that a temperature gradient that is less than 10 °C develops, meaning it is safe for use. The prototype was designed with artificial friction to prevent the blinds from slipping when not in use. An experimentally validated motor model was developed and used to determine that the system could use up to 46% less energy if the artificial friction was removed. A pseudo-empirical system model was developed to simulate the interaction between system electronics. Simulation results indicate that the system would remain consistently powered if placed behind a south-facing window that receives a consistent supply of direct sunlight and attenuates that light by less than 75%. These results also indicate that the unit would remain powered in the absence of light for 13 days. Similar methods could be used to evaluate future energy harvesting systems.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Reproductive Competition and Success in a Joint-Nesting Cuckoo

contributor:
Quinn, Dr. James S
Biology

subject:
Co-operative Breeding
Reproduction

abstract:
Joint-nesting species experience complex and diverse social environments which can
influence individual reproductive success. When social groups are formed by non-
relatives, competition for representation in incubated clutches can be intense and result
in substantial reproductive losses. Because conflicts of this nature have direct impli-
cations on fitness, resolutions and outcomes of such are of particular interest to evolu-
tionary research. For this reason, I explored patterns of reproductive competition and
skew in joint-nesting Smooth-billed Anis (Crotophaga ani). In chapter I, I show marked
differences in multivariate bill and body size between sexes of Smooth-billed Anis (Cro-
tophaga ani) despite reportedly reduced sexual dimorphism in co-operative breeders. I
also show that multivariate bill size in males correlates with annual reproductive success
and individual contribution to clutches from multiple parents. A similar trend is not
observed in females, suggesting potential for sexual selection on male bill size. Together,
these data provide evidence for morphological influences on reproductive fitness in joint-
nesting species. In chapter II, I show that relative parental effort is positively correlated
with reproductive fitness in social groups of Smooth-billed Anis. Nocturnal incubation is
risky and is biased toward a single male - akin to Groove-billed (Crotophaga sulcirostris)
and Greater Ani (Crotophaga major). I report heightened reproductive contribution by
nocturnally incubating males when compared to other males within social groups. In
chapter III, I tested whether social group size is correlated with endocrine markers of
stress in adult male and female Anis. Using a novel enzyme linked immunosorbent as-
say, I show that corticosterone (the primary glucocorticoid in birds) deposited in feathers
is highest in birds from atypically large social groups. While the direct consequences
of elevated corticosterone on reproductive fitness in Anis is yet unknown, these results
suggest that breeding in large social settings is likely to be physiologically expensive.

abstract: Thesis

abstract: Master of Science (MSc)


title: Properties and Derivatives of Cyclic Sulphur Imides

contributor:
Olsen, F. P.
Chemistry

subject: properties, derivatives, cyclic, sulphur, imides

abstract: The methylation of three isomeric hexasulphur diimides under basic conditions has been investigated. Both mono- and dimethylated products have been obtained from the 1, 5- and 1,4-hexasulphur diimides. The anion formed from the 1,3 isomer was found to undergo decomposition, the major products being polysulphides and N-methyl heptasulphur imide. The usefulness of proton NMR, mass spectra, and infrared spectra in conjunction with these compounds has been considered.

abstract: Thesis

abstract: Master of Science (MSc)


title: Injective Hulls of Modules

contributor:
Banaschewski, B.
Mathematics

subject: injective, hulls, modules

abstract: By an injective hull of a module M over any ring we mean a minimal injective extension module E ≥ M. Our main objective in this thesis is to find an explicit description of injective hulls of modules in some special cases and to study their properties.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Studies on Vanadium Analyses of Stretford Liquors

contributor:
Hileman Jr., O. E.
Chemistry

subject: vanadium, Stretford, liquors, industrial, gas streams

abstract:
 A brief review of the industrial methods employed to remove hydrogen sulfide from contaminated gas streams is given, with particular emphasis centred on the Stretford process.

 A summary of some recent developments in the solvent extraction of vanadium(5) is also given, together with the relevant aqueous vanadium chemistry.

 The experimental section deals with the development and optimization of an analytical procedure for vanadium(5) determination in alkaline solution. This developed procedure is then applied to the analysis of Stretford liquor.

abstract: Thesis

abstract: Master of Science (MSc)


title: An Investigation of the Crystal Structure of Mn2P2O7

contributor:
Calvo, C.
Physics

subject: crystal, structure, manganese, atoms, oxygen, bonding, x-ray

abstract:
 Mn2P2O7 belongs to the monoclinic space group C2/m. The manganese atoms are six-fold coordinated to oxygen atoms forming distorted octahedra. The bonding in P2O7^4- ion is discussed with reference to values predicted by Cruickshank and Baur.

 The central oxygen atom in P2O7^4-ion shows enhanced motion, a feature common to all the members of the thortveitite series. By collecting X-ray data at -180°C, an attempt has been made to understand the nature of this enhanced motion.

abstract: Thesis

abstract: Master of Science (MS)


title: Truncated Ordered Stick Breaking Financial Market Model and Corresponding Bayesian Estimation

contributor:
Feng, Shui
Mathematics and Statistics

subject:
Poisson-Dirichlet
GEM
Stick Breaking Process
Financial Market

abstract: Several truncated models for market weights are discussed. To summarize, the new truncated ordered stick breaking model introduced give restrictions on the ranks of the markets weights and show better fitting results for real data sets.

abstract: Thesis

abstract: Master of Science (MSc)


title: Impact Analysis: Planning and Retailing Implications of Hamilton's New Eaton's Centre

contributor:
Reader, Steven
Geography

subject: planning, retailing, implications, Hamilton, New Eaton Centre

abstract:
Abstract Not Provided.
Thesis
Bachelor of Arts (BA)


title: Impact of Diabetes Mellitus and Associated Changes on Skeletal Muscle and its Stem Cell Population

title: Satellite Cells in Diabetes Mellitus

contributor:
Hawke, Thomas J.
Medical Sciences

subject:
Satellite Cell
Skeletal Muscle
Diabetes Mellitus

abstract: Diabetes Mellitus is chronic lifelong condition that continues to be a global health concern. Despite the development of insulin therapy in 1921, many diabetics are likely to endure a number of co-morbidities that impact their quality of life.  Today, the search for additional diabetic therapies incorporates the investigation of various organ systems for their potential in attenuating disease development. Skeletal muscle is a striated tissue that is integral to metabolism, movement, and overall wellbeing, yet its significance to Diabetes Mellitus remains understudied, as compared to other metabolic tissues. Previous work has identified that diabetes promotes adverse changes to skeletal muscle physiology, function, and morphology, contributing to a complication referred to as diabetic myopathy. The capacity to adapt to changing internal and external cues, as achieved through skeletal muscle plasticity, permits the maintenance of skeletal muscle health; a term encompassing its metabolism, function, and/or structure. This malleability is primarily regulated by the function of muscle progenitor stem cells, referred to as satellite cells. While past research has shown that satellite cells are hindered in various diabetic states, the precise mechanisms through which these observations occur remain to be elucidated. The data presented herein identify impaired satellite cell activation in two sub-types of diabetes (Pre-Diabetes and Type 1 Diabetes), and shows that such results are mediated by alterations to intrinsic signalling cascades. Additional insight into a potential unifying mechanism mediating this response led to the identification of Lipocalin-2 and its influence on satellite cell function and muscle plasticity. The results uncovered in these studies have enhanced our understanding of the response of satellite cells in diabetes, and have identified a prospective therapeutic target for the attenuation of diabetic myopathy.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: QF-1 Rings

contributor:
Mueller, B. J.
Mathematics

subject: rings, module, artinian

abstract: A ring R is said to be QF-1 if every finitely generated faithful R-module has the double centralizer property (or is balanced). A necessary and sufficient condition for an artinian ring to be QF-1 is given. The class of QF-1 rings properly contains the class of QF rings and this is shown by an example. Several constructions of modules which are not balanced are collected. Finally, the structure of artinian local QF-1 rings which are finitely generated over their centers is gotten. This is a generalization of theorems of Floyd, and, Fuller and Dickson.

abstract: Thesis

abstract: Master of Science (MSc)


title: Growth Poles, Growth Centers and Politics: An Examination of their Roles in Development

contributor:
Dear, M. J.
Geography

subject: growth, poles, centers, politics, development

abstract:
 This paper is a general examination of the applicability of the growth pole and the growth center concepts to development planning in underdeveloped nations. It is found that, because of the problems which are unique to each concept and the characteristics which are unique to each economic setting, the notions are not generally applicable. Analysis also suggests that the prime factor determining the success or failure of any development strategy is the political environment of the host country. The future does not appear to be particularly bright, due to the lack of progress with these growth notions and the existence of no real alternatives, and
due to the political and institutional inertia prevalent within underdeveloped nations.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: Estimation of the Surface Radiation Balance and Components for a Tropical Ocean

contributor:
Davies, J. A.
Geography

subject: surface radiation, balance, components, tropical ocean, water vapour

abstract:
 The radiation balance at a ship station in the eastern tropical Atlantic Ocean is calculated using a term-by-term approach. Irradiances are calculated using upper air data from four daily radiosonde ascents and hourly surface weather observations made at the Canadian vessel 'Quadra' during GATE Phase 1 (June- July, 1974).

 Global irradiance is calculated by a cloud layer model similar to that used by Davies et al in Southern Ontario, Canada. The model considers first, cloudless sky attenuation of solar irradiance by water vapour, ozone and Rayleigh scattering. Second, cloud effects are added by considering contributions from three cloud layers - high, middle and low and secondary radiation from cloud base of reflected surface radiation. Reflected solar irradiance is calculated using a mean sea-surface albedo of 6% suggested by Payne for that part of the Atlantic Ocean.

 Estimates of incoming longwave irradiance are made first, from a numerical flux emissivity model which uses radiosonde ascent data and cloud amount at three heights and second, from a simple model which uses surface temperature and total cloud amount.

 Outgoing longwave emittance is evaluated using surface temperature and an emissivity of 0.98. The radiation balance is then obtained as the algebraic sum of the four components.

 The estimated values are compared with values measured at 'Quadra'. In 70% of the cases, calculated and measured solar irradiance agree to within 20%. Model performance for cloud amount > 5/10 is least satisfactory.

 In all cases, model and measured values of daily incoming longwave irradiance agree to within 5%. In 60% of the cases, measured and calculated radiation balance agree to within 20%.

abstract: Thesis

abstract: Master of Science (MSc)


title: Polyatomic Cations of Sulphur, Selenium and Tellurium

contributor:
Gillespie, R. J.
Chemistry

subject: polyatomic, cations, sulphur, selenium, tellurium, compounds, cations

abstract:
 The preparation of compounds containing polyatomic cations of sulphur, selenium and tellurium has been investigated by using oxidising agents such as AsF5, SbF5, S2O6F2 and SO3. New compounds, containing polyatomic cations Se8 2+, Se4 2+, Te3n n+, Te4 2+ Ten n+, S16 2+, S8 2+ and S4 2+, and anions of very strong acids such as Sb2F11- and AsF6- were isolated and characterised by a combination of the stoichiometry of the preparation
reactions, UV-visible spectrophotometry, Infrared and Raman spectroscopy and magnetic susceptibility measurements.

 Solutions of sulphur in various concentrations of oleum were investigated in detail by UV-visible spectrophotometry and e.s.r. spectroscopy.
Evidence is presented for the formation of the sulphur cations S16 2+, S8 2+ and S4 2+ in these media, and for the presence of low concentrations of the radical cations S8+ and S4+.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Investigating hyperglycemic bone formation with high resolution microscopy techniques

contributor:
Grandfield, Kathryn
Biomedical Engineering

subject:
High-Resolution Microscopy
Diabetes
Hyperglycemia
Bone Healing
Bone Mineralization
Bone Nanostructure
Bone Microstructure

abstract:
Consensus in scientific literature is that hyperglycemia, which is a condition that manifests in individuals with uncontrolled diabetes, causes compromised bone growth, but the exact mechanisms of are unknown. It has been estimated that 5% of dental implant failures that have previously been linked to unknown causes may be associated with undiagnosed diabetes. It is important to study the early stages of bone growth as it is accepted that they are critical in the long-term success rate of endosseous implants. This study aimed to investigate the bone healing seen in the hyperglycemic group compared to the normal (i.e. control) group, at an early time point, using high-resolution microscopy techniques.
   Ten young (200-250gram) male Wistar rats were used for this study with five rats assigned to the control group and the other five rats intravenously injected with 65 mg/kg of streptozotocin (STZ) to induce diabetes. An osteotomy model was used to make a 1.3mm defect in the diaphysis of the rat femurs. After five days, the femurs were removed, fixed in glutaraldehyde, dehydrated, and embedded in resin. Structural and chemical analyses were conducted on the samples using a variety of microscopy techniques to examine various factors of bone quality including: bone porosity, relative mineralization level, and the arrangement of collagen and mineral.
   When analyzing the micro-structure, the hyperglycemic group showed increased porosity in the newly formed bone as compared to the control group. However, no significant differences were found in the nano-structure when analyzing the arrangement of collagen and mineral.Therefore, the results in this thesis suggest that alterations in micro-architecture rather than nano-architecture may play a pivotal role in the compromised bone healing in uncontrolled diabetes at this five-day time point. Future work should investigate additional time points in the bone healing process.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: According to the International Diabetes Federation, 387 million people worldwide are living with diabetes of which 46.3% are undiagnosed. Uncontrolled diabetes results in hyperglycemia, which is a condition where there is an increased level of glucose in the blood. When diabetes is not regulated correctly with medication, it leads to problems in the long-term success rate of dental implants. The objective of this thesis was to investigate the early stages of bone formation, which are accepted to be critical in the long-term success rate of dental implants, in hyperglycemic animal models compared to control groups using various microscopy techniques. The different techniques used allowed for the structural and elemental compositions of bone to be studied on the micro-scale and nano-scale. It was shown that at the 5-day healing time point studied, the micro-structure, rather than the nano-structure, was negatively altered in the hyperglycemic group compared to the control group.


title: SYNTHESIS OF FLUORENE-BASED π-CONJUGATED POLYMERS AND THE STUDY OF THEIR INTERACTION WITH SWNTs

contributor:
Adronov, Alex
Chemistry and Chemical Biology

subject:
conjugated polymer
carbon nanotubes
fluorene

abstract:
Single-walled carbon nanotubes (SWNTs) are envisioned as one of the most promising materials for next-generation electronic devices such as field-effect transistors, photovoltaics, new power sources and bio/chemical sensors. In particular, solution processable SWNT networks are of great interest for flexible and stretchable electronics. However, most of these applications specifically require pure semiconducting (sc-) or metallic (m-) SWNTs.  However, large scale synthetic methods for SWNTs always produce a mixture of semiconducting and metallic carbon nanotubes. In recent years, several biochemical separation techniques such as DNA assisted separation, density gradient ultracentrifugation, and gel chromatography techniques have been utilized to separate semiconducting and metallic SWNTs. Although these methods can be used for sorting SWNTs according to their chiralities, they are either time-consuming or not easily scalable. In addition, the supramolecular functionalization of SWNTs with conjugated polymers has received a great deal of attention due to its capability to extract sc-SWNTs via simple sonication and centrifugation steps within a few hours. Furthermore, π-conjugated polymers can be modified by suitably changing monomers and/or comonomers, and it is also easy to control molecular weight and solubility of resulting polymers in organic solvents and aqueous media. There is also the possibility for selectively extracting specific chirality (n, m) nanotubes using specifically designed macromolecular structures. Except for its application to the separation of SWNTs, the supramolecular complexes of π-conjugated polymer and SWNTs have potential applications in many research areas such as new composite materials.
After a brief overview of the current work related to the investigation of the supramolecular interaction between various conjugated polymers and SWNTs (chapter 1),  synthesis of a series of different types of fluorene-based conjugated copolymers and their supramolecular complex formation properties with SWNTs are described (chapter 2, 3, 4, 5 and 6). In order to understand the effect of conjugated polymer backbone and side-chain structure on formation of supramolecular complexes with SWNTs, several crucial factors were investigated by: (1) altering the polymer backbone composition; (2) introducing different solubilizing (functional) groups while the polymer backbone remains the same; (3) changing the side-chain functional groups, and (4) introducing different polymer repeat units with varying physical and chemical properties.  The experimental results indicated that all of the resulting polymer-SWNTs complexes possess excellent (or moderate) solution stability in organic solvents such as tetrahydrofuran (THF), toluene, and xylene. It was also demonstrated that the interaction between the conjugated polymers and SWNTs is strongly influenced by polymer structure; even minor changes on side-chains have a significant effect on the selectivity of the polymers in dispersing specific SWNT structures.
This investigation highlights the potential importance of incorporating different types of heterocyclic aromatic rings (electron rich or electron poor), and introducing side chains with varying electronic and geometric structure on selective solubilization of SWNTs. Polymer molecular weight and solvent properties also strongly influence the π-conjugated polymer assisted dispersion of specific chirality SWNTs. Although some progress has been made, the search for a conjugated polymer that selectively solubilizes specific SWNT chiralities on large scale remains a challenge.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)