title: Communication Between Family Physicians and Individuals with Dementia at the Time of Diagnosis

contributor:
Denton, M.
Ryan, E. B.
Bourgeault, I.
Sociology

subject:
family physicians
dementia
diagnosis
patients

abstract: Physicians are usually the first contact in the health care system for persons with dementia and their family caregivers. Although specialists typically make the diagnosis, it is the family physician who is key to confirming the diagnosis for dementia, explaining what it means physically, emotionally, and describing what to expect as the disease progresses. Our knowledge about interaction between persons with dementia and their physicians is based largely on the caregiver's view while few studies have investigated the physician's perspective. Persons with dementia have been underrepresented in research pertaining to the issue of diagnosis disclosure. The aim of this exploratory study was to examine the attitudes of family physicians and individuals with early stage dementia about the diagnostic process. The effects of a companion on a medical encounter were also investigated. Data were compiled from responses of 14 family physicians to a structured questionnaire containing highly selective questions, as well as in-depth interviews with 9 individuals with dementia. Using a conflict theoretical framework, the results show that family physicians do inform patients of a diagnosis for dementia. Although the majority of individuals with dementia are satisfied with their family physicians' communication, they were dissatisfied in terms of referral to community resources. Persons with dementia also felt that they received less than ideal care, particularly from specialists, in terms of how the diagnosis was disclosed. Overall, physicians and persons with dementia rated the influence of a third person in the medical encounter as positive. Physicians in this study continued to use an illness-centered approach rather than a patient-centered approach that acknowledges the patient as a person with unique needs and a life-story. Future research thus needs to address the development of a patient-centered model in which the understanding of the subjective experience of the person with dementia is essential.

abstract: Thesis

abstract: Master of Arts (MA)


title: The Phenomenon of Substitution and Asperger's Syndrome a Phenomenological Analysis

contributor:
Sassen, Brigitte
Philosophy

subject:
substitution
asperger's syndrome
phenomenological analysis

abstract: This thesis suggests that the alliance between contemporary Psychology and Merleau-Ponty's Phenomenology provides a more complete analysis of the embodied experience of persons with Asperger's Syndrome (AS). This alliance would rely upon the first person experiences of those with AS in addition to the physiological analysis and observations provided by those in Contemporary Psychology. By examining the analysis provided by contemporary psychologists within in the framework of the philosophy of Merleau-Ponty, the 'whole' of the embodied experience of persons with AS will be revealed. The analysis of Dr. Simon Baron-Cohen, one of the foremost contemporary psychologists in the field of autism is examined. I will conclude that Baron-Cohen privileges interpersonal interaction while overlooking other types of interaction by an embodied being within the phenomenal world. First person accounts written by Temple Grandin, Ph.D. and Dawn Prince-Hughes, Ph.D., both persons with AS, are relied upon for the analysis of an alliance between the two disciplines. Critical to this examination is Merleau-Ponty' s Phenomenon of Substitution, the 'seat of illness', and the 'third term'. Also discussed will be issues of boundaries that serve to separate the neurotypical from those persons with AS. These boundaries serve to diminish the potential and accomplishments of those persons with AS while attempting to maintain the hierarchical supremacy of those who are neurotypical.

abstract: Thesis

abstract: Master of Arts (MA)


title: Speech Perception and Motor Control in Children and Adolescents with Down Syndrome

title: Speech and Motor Control in Children with Down Syndrome

contributor:
Elliott, D.
Human Biodynamics

subject:
speech perception
motor control
children
adolescents
down syndrome

abstract: Twelve children without intellectual disability and 12 children and adolescents with Down syndrome were administered a short form of Roy and Black's (1998) Apraxia Battery. Participants with Down syndrome also completed a free-recall dichotic listening test. While the mean laterality indices for the group with Down syndrome was negative, indicative of a left ear-right hemisphere specialization for speech perception, they were not significantly different from zero. There was a wide range of individual variability in laterality, and individuals with a left ear advantage for speech perception performed more poorly on the portions of the apraxia battery that involved verbal instruction. The possibility that individuals with Down syndrome who have apraxia may constitute an important subset of individuals with Down syndrome was considered. The results are discussed within the framework of Elliott, Weeks, and Elliott's (1987) biological dissociation model.

abstract: Thesis

abstract: Master of Science (MS)


title: Design and Evaluation of a Self-Paced Learning Resource Booklet for Caregivers of Individuals with Alzheimer's Disease

title: Evaluation of Booklet for Caregivers of Alzheimer's Disease

contributor:
Synge, Jane
Black, Margaret

subject:
self-paced learning
alzheimer's disease
learning resource booklet
caregivers

abstract: Research in the last decade has focused on the impact of the caregiver role (Cantor, 1983), the nature of caregivers (Brody, 1981, 1983), and the stress and burden associated with caregiver (Zarit, Todd and Zarit, 1986). Health professionals working with caregivers have attempted to focus on interventions to reduce feelings of burden and to increase effective coping. Evaluation of educational interventions to reduce caregiver stress and burden has been a recent research focus. Unfortunately, research has shown that it is altruistic to believe that caregiver stress and burden can be alleviated by educational interventions. Family caregivers are faced with the task of learning about the nature and complexity of dementia and the unusual behaviours which accompany Alzheimer's disease. A resource booklet, written to assist caregivers to learn about the disease, about management strategies and about their own feelings may be more effective than interventions to reduce stress. The evaluation focused on whether the resource booklet would provide information which family caregivers would perceive to be relevant and useful. The evaluation was conducted using a convenience sample of ten caregivers. Two time intervals were used to collect information on caregivers' reactions to the resource booklet; one week following the initial reading of the booklet and 4-6 weeks post-reading. A written questionnaire at time one, and follow-up telephone interviews at time two, were used to measure caregivers' reactions to the booklet. Results indicated that the information in the booklet was useful in assisting caregivers to manage care, and that the caregivers found the booklet easy to read and the format acceptable.

abstract: Thesis

abstract: Master of Science (Teaching)


title: Towards an Integrated Water Quality Monitoring System Using Low Cost Electrochemical Sensors

contributor:
Howlader, Matiar M R
Deen, M Jamal
Electrical and Computer Engineering

subject:
Electrochemical Sensors
Water Quality
Pharmaceuticals Sensor
pH Sensor
Free Chlorine Sensor
Heavy Metal Sensor
Integrated System
Lead Sensing
Carbon nanotubes
β-Cyclodextrin
Printed Circuit Board
Smartphone Application
Temperature Sensor
Integrated Sensors
Potentiometric Sensor
Potentiodynamic Sensor

abstract:
The monitoring of pharmaceuticals, heavy metal, pH and free chlorine concentration in drinking water is important for public health and the environment. However, conventional laboratory-based analytical methods are labor-intensive, expensive, and time consuming. This thesis focuses on developing an integrated, highly sensitive, easy-to-use, and low-cost pharmaceuticals, heavy metal, pH and free chlorine sensing system for drinking water quality monitoring.
A low-temperature, solution-processed modification of multi-walled carbon nanotubes (MWCNT) with β-cyclodextrin (βCD) on glassy carbon electrode is developed for detecting low levels of acetaminophen. The adsorption properties of βCD are combined with the high surface area of carbon nanotubes towards enhanced electrochemical sensing of acetaminophen with a limit of detection of 11 nM and linear range from 0.05-300 μM. Also, a systematic investigation is carried out using four types of modified MWCNT-βCD. A novel, one-step approach called Steglich esterification modified MWCNT-βCD results in large effective surface area, and fast electron transfer towards sensitive detection of acetaminophen and 17β-estradiol (E2, primary female sex hormone) in the range of 0.005–20 and 0.01–15 μM, with low detection limits of 3.3 and 2.5 nM, respectively. The similar MWCNT-βCD modified electrodes can also detect heavy metal ion (lead, Pb2+) with a limit of detection of <10 ppb. Low frequency noise behavior of these sensors are studied.
A spin-coated Pd/PdO based pH sensor, and amine-modified carbon electrode-based free chlorine sensor are fabricated on a common substrate together with the pharmaceuticals and heavy metal sensors. A Wheatstone-bridge temperature sensor is fabricated based on silicon and PEDOT:PSS on another substrate. All the sensors are connected to an Arduino microcontroller based data acquisition system with a smartphone application interface. The integrated sensing system is easy-to-use, low-cost, and can provide accurate monitoring data with real drinking water samples.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Low-cost, easy-to-use, and sensitive monitoring system for pharmaceuticals, heavy metal, pH and free chlorine in drinking water is crucial for public health safety. In this thesis, we develop solution-based synthesis of multi-walled carbon nanotubes modified by β-cyclodextrin for electrochemical sensing of pharmaceuticals and heavy metal. The modification approaches are compared and characterized to analyze their electrochemical behavior and sensing performances. The developed sensors are highly sensitive toward the detection of acetaminophen (a widely used pain-killer) and estrogen hormone in drinking water. We also develop a modified spin-coating technique to deposit palladium/palladium oxide films for potentiometric pH sensor, a calibration-free free chlorine sensor based on modified carbon electrode, and a resistive temperature sensor. The developed pH, free chlorine and temperature sensors are highly sensitive, and stable with fast response time. All the sensors are integrated and interfaced with a custom-made and smartphone-controlled electronic readout system for accurate and on-site drinking water quality monitoring at low cost.


title: The Geography of Mental Health: Housing Ex-Psychiatric Patients

contributor:
Taylor, S. M.
Geography

subject:
mental health
housing
human geography
ex-psychiatric patient

abstract:
As a result of deinstitutionalization in the 1960s and 1970s, a great many chronically mentally ill psychiatric patients were released into an ill-prepared community. One of the major problems facing the discharged patient is housing. This thesis focuses on the housing situation and experience of the chronically mentally ill, which is recognized as one of several sets of interrelated environmental factors affecting their ability to cope in the community. The housing situations of a sample of 66 chronically mentally ill individuals in Hamilton were examined by way of cross-sectional and longitudinal survey data collected as part of a larger study of the community environment factors affecting the quality of everyday life among the chronically mentally ill. The specific objectives of the research were: (a) a description of the housing experience of the chronically mentally ill in Hamilton; ( b ) an analysis of the residential mobility of the research sample; (c) a description of the expressed housing need of the chronically mentally ill individual in the community; and, (d) a comparison of the need expressed by the sample
with the normative housing need espoused in the literature in order to gauge the 'fit' between the two.
The data show the sample clustered in the inner-city of Hamilton in lodging-home types of accommodation. An analysis of residential mobility reveals two trends. First, the sample have little control over their living situation. Second, there are two sub-groups within the sample: one which is relatively residential l y stable and one which is excessively mobile. A logit analysis shows the factors affecting mobility to be level of education and preference for an independent living situation. Knowledge of these factors could aid in the task of matching client needs to appropriate living situations. An analysis of the expressed housing need of the sample reveals that the long-term housing goal expressed by the sample is not dissimilar to the normative housing need defined in the literature: independent community living. However, there appear to be substantive infrastructural ) and procedural (lack of advocacy housing placement) gaps between the housing need as defined and the current housing stock.

abstract: Thesis

abstract: Master of Arts (MA)


title: Optimal Distributed Detection of Multiple Hypotheses Using Blind Algorithms

contributor:
Wong, Kon
Jeremic, Aleksandar
Electrical and Computer Engineering

subject:
detection
multiple hypotheses
blind algorithms

abstract:
In a parallel distributed detection system each local detector makes a decision based on its own observations and transmits its local decision to a fusion center, where a global decision is made. Given fixed local decision rules, in order to design the optimal fusion rule, the fusion center needs to have perfect knowledge of the performance of the local detectors as well as the prior probabilities of the hypotheses. Such knowledge is not available in most practical cases. In this thesis, we propose a blind technique for the general distributed detection problem with multiple hypotheses. We start by formulating the optimal M-ary fusion rule in the sense of minimizing the overall error probability when the local decision rules are fixed. The optimality can only be achieved if the prior probabilities of hypotheses and parameters describing the local detector performance are known. Next, we propose a blind technique to estimate the parameters aforementioned as in most cases they are unknown. The occurrence numbers of possible decision combinations at all local detectors are multinomially distributed with occurrence probabilities being nonlinear functions of the prior probabilities of hypotheses and the parameters describing the performance of local detectors. We derive nonlinear Least Squares (LS) and Maximum Likelihood (ML) estimates of unknown parameters respectively. The ML estimator accounts for the known parametric form of the likelihood function of the local decision combinations, hence has a better estimation accuracy.
Finally, we present the closed-form expression of the overall detection performance for both binary and M-ary distributed detection and show that the overall detection performance using estimated values of unknown parameters approaches quickly to that using their true values. We also investigate various impacts to the overall detection. The simulation results show that the blind algorithm proposed in this thesis provides an efficient way to solve distributed detection problems.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Atypical Functional Organization of the Brain in Dyslexia

contributor:
Witelson, S. F.
Psychology

subject:
dyslexia
atypical functional organization
brain
brain organization

abstract: Atypical functional organization in the brains of adult male dyslexics was investigated through the divided visual field (DVF) paradigm. By intentional manipulation, equal levels of overall performance between groups were obtained, which made clearer interpretation of the results possible. Both dyslexic and control subjects appeared to have left hemisphere specialization for nonsense words. Dyslexics exhibited no asymmetry for face recognition indicating bilateral representation of this function in their brains, while control subjects exhibited the expected left visual field advantage. The results are considered both as group means and as frequency data. The results provide modest support tor the hypothesis that dyslexics have atypical functional organization.

abstract: Thesis

abstract: Master of Arts (MA)


title: Structuration Theory and the Ghettoization of Ex-Psychiatric Patients

contributor:
Dear, M. J.
Geography

subject:
structuration theory
ghettoization
ex-psychiatric patients

abstract: In this thesis, Giddens' theory of structuration is employed in an analysis of the ghetto of ex-psychiatric patients in Hamilton, Ontario. A review of the main concepts of of structuration theory forms the basis for a theoretical model of the structuration of urban space that considers both the individual agent and the social system as equal partners in the production and reproduction of the urban built environment. From this general model, methodologies are developed for institutional analysis and an analysis of strategic conduct. The institutional analysis enables an understanding of the ghetto as the unintended outcome of deinstitutionalization policy. An examination of the city of Hamilton's attempt to dismantle the ghetto focuses on the strategic conduct of the actors in the policy-making process, and provides insight as to why the city's attempt has thus far proved unsuccessful in halting the ghettoization of ex-patients. The study demonstrates the theoretical and empirical utility of structuration theory in providing an analysis that considers the complex interrelationships of system, structure, agency, time and space.

abstract: Thesis

abstract: Master of Arts (MA)


title: Adaptive Noise Cancellation of Brainstem Auditory Evoked Potentials using Systolic Arrays

contributor:
deBruin, H.
Electrical Engineering

subject:
adaptive noise cancellation
brainstem
auditory potentials
systolic arrays

abstract: Brainstem Auditory Evoked Potentials (BAEP) contain valuable information about the condition of the neural fibers associated with the auditory pathways. Extraction of this information is a difficult task due to contamination by on-going scalp EEG. This thesis reviews the current processing techniques and introduces adaptive noise cancellation (ANC) using systolic arrays as an alternative to existing technology. Q-R decomposition theory is reviewed and an explanation of the mechanics of systolic adaptive noise cancellation (SANC) is presented. A modified Given's rotation algorithm is derived resulting in a saving of up to 2/3 in memory requirements. Real data were collected in the laboratory. Real and simulated data were processed to determine the characteristics and effectiveness of adaptive noise cancellation strategies. Successful ANC of BAEP was performed on simulated data using a number or signal-to-noise ratios (S/N), data sequence lengths, reference signals and filter parameter values. We conclude that systolic arrays are a very powerful and appropriate technique for the extraction or BAEPs. Correlation studies indicated that the pre-stimulus EEG signal is inadequately correlated to the primary signal for successful ANC or BAEP in real data. A multi-channel collection scheme is outlined for future collection or Evoked Potential data. A summary or experimental results is presented to address the problem or data collection and signal processing optimization.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Detection of Human Papillomavirus Type 16 in Invasive Cervical Cancer by Polymerase Chain Reaction

contributor:
Rawls, William
Biology

subject:
human papillomavirus
hpv type 16
cervical cancer
polymerase chain reaction

abstract: Human papillomaviruses (HPV) have been implicated as etiologic agents in the genesis of cervical carcinoma and certain other benign lesions of the cervix. Clinical and epidemiological data, and the demonstration of HPV 16 viral DNA sequences in cervical cancer biopsies lend support to the etiologic association of HPV type 16 and cervical carcinoma. Interpretation of the association between HPV 16 and cervical cancer is limited by methods of detection. Different methods of detection of viral DNA sequences have been used based on DNA-DNA hybridization. Recently, a method based upon the in vitro enzymatic amplification of specific viral DNA sequences or polymerase chain reaction (PCR) has been used. The purpose of this study was to compare PCR with DNA-DNA hybridization methods in clinical specimens obtained from invasive cervical cancer. The in vitro enzymatic amplification or PCR was carried out on three specific regions of HPV 16. E6, E7 and L1 regions of HPV 16 were chosen as the target sequences of amplification and primers were synthesized specific to these regions. PCR was performed on 163 cervical cancer specimens using primers specific for E6 and E7 regions of HPV 16. 112 of these specimens were also analyzed using L1 primers of HPV 16. Estimates of sensitivity and specificity of the different methods to see if PCR is a better, more sensitive method compared to the other methods were computed. The results suggest that although percent positivity by PCR method increases significantly, thereby improving sensitivity of detection, the specificity suffers compared to the other methods. However the advantages of using PCR as a diagnostic tool are attractive, as it requires only picogram quantities of DNA, is rapid and easy to perform, and is amenable to automation.

abstract: Thesis

abstract: Master of Science (MS)


title: The Role of GRB2 and GRB7 in Polyomavirus Middle T Antigen- and Neu-Mediated Mammary Tumorigenesis

title: GRB2 and GRB7 in Mammary Tumorigenesis

contributor:
Muller, W. J.
Biology

subject:
GRB2
GRB7
polyomavrius
T antigen
neu-mediated mammary tumorigenesis
mammary tumorigenesis

abstract: Activated protein tyrosine kinases, which have been implicated in the genesis of a number of human cancers, rely on a variety of protein-protein interactions to transmit their proliferative signals within the cell. These interactions are often mediated by Src homology 2 and 3 (SH2 and SH3) domains. A class of proteins which are mainly composed of such domains, termed adaptor proteins, has been identified. The Growth factor receptor bound proteins Grb2 and Grb7 are SH2 domain adaptor proteins which have been shown to associate directly or in complex with many tyrosine kinases, including the c-ErbB-2/Neu receptor tyrosine kinase. While overexpression of either protein alone in rat fibroblasts is not transforming, human breast cancer cell lines exhibit Grb2 and Grb7 gene amplification, and mRNA and protein overexpression. The role of Grb2 in polyomavirus middle T antigen-mediated mammary tumorigenesis has been examined utilizing gene targeting and transgenic approaches. Initial characterization of the progeny of matings involving Grb2+/mice and MMTV/middle T transgenic mice indicated that delayed tumor kinetics may be the result of Grb2 dosage differences between mT+;Grb2+/-and mT+;Grb2+/+ animals. Transgenic animals expressing a dominant negative version of Grb2 in the mammary epithelium have been generated to explore an alternate method for disrupting signaling from middle T antigen. The role of Grb2 and Grb7 in Neu-mediated mammary tumorigenesis is also being examined. Both MMTV/Grb2 and MMTV/Grb7 transgenic mice that express the transgene in the mammary epithelium have been identified by ribonuclease protection analysis. Matings involving these strains and MMTV/neu mice should aid in determining the effects of overexpressing Grb2 or Grb7 on Neu-mediated mammary tumorigenesis.

abstract: Thesis

abstract: Master of Science (MS)


title: A Novel Coil Design for Magnetic Nerve Stimulation

contributor:
Findlay, Raymond
Electrical Engineering

subject:
coil design
magnetic nerve stimulation

abstract: Magnetic nerve stimulation is a non-invasive method of exciting a neural tissue which can be achieved by exposing the body to a transient magnetic field. This field is generated by passing a high current through a coil over a short period of time. By positioning this coil in a specific orientation over the targeted nerve, the time variation of the magnetic field will create an electric field in the conductive milieu of the body. Induced currents will result from that electric field. If those currents reach a certain amplitude within a specific time period this will cause a neural depolarization. This depolarization will enable us to test and examine the excited nerve which will provide us with the necessary data for an effective treatment. In my thesis I will analyse the benefits of magnetic nerve stimulation with the objective of designing a coil that provides a focussed magnetic field. This field will excite the targeted nerve with minimal or to no excitation to the surrounding nerves. This means that we can effectively apply or measure the excitation of the targeted nerve without involving the surrounding nerves. It is my intention to bring this application to a practical platform where a simple circuit with lower power requirements can be used. This will enable some patients requiring physiotherapy to safely administer magnetic nerve stimulation to themselves without the help of a therapist.

abstract: Thesis

abstract: Master of Engineering (ME)


title: A Comparison of Clinical Assessment Versus Force Platform Assessment of Postural Instability in Parkinson's Disease

contributor:
Starkes, J. L.
Human Biodynamics

subject:
clinical assessment
force platform assessment
postural instability
parkinson's disease

abstract:
The purposes of this study were: (1) to determine whether there was a correlation between a quantitative assessment of postural sway , and a clinical assessment of postural stability, in patients diagnosed with idiopathic Parkinson's disease (PD); (2) to plot individual diurnal changes in postural sway characteristics of PD patients over an eight-hour time period; (3) to plot day to day changes in individual postural sway characteristics of PD patients: (4) to determine whether there was a difference in the postural sway characteristics of parkinsonians, with and without vision; (5) to determine whether there was a difference in the postural sway characteristics of the same individuals when using either Sinemet or Oeprenyl.
Three male PD patients were recruited into this study. Each subject stood on a stable force platform (AMT1 OR6-5-1). Measurements included the standard deviations of the coordinates of the centre of pressure (COP) in the anterior-posterior (a-p) and lateral (lat) directions, the mean velocity of sway, and area of sway. These dependent measures were evaluated in a "quiet standing" condition, once with the eyes open (EO) and once with the eyes closed (EC). These procedures were carried out ten times over the course of an eight hour day. Each subject was tested two days while taking eight hour day. Each subject was tested two days while taking Sinemet, and two days while on the Deprenyl regimen. Secondly, at two periods of each test day, each patient was evaluated using the postural assessment section of the Sears Parkinson's Assessment Form (SPAF). The results were: (1) group analyses and individual analyses established the evidence of significant correlations between both the quantitative measures of postural sway (force platform) and the qualitative assessment tool (SPAF): (2) significant variability was evident in the analysis of individual data plots: (3) no statistically significant differences were observed tor any subject when measured from day to day; (4) generally, vision was a stabilizing factor in postural control, however, this was quite variable for each subject; (5) significant improvements in postural stability were observed with the introduction of Deprenyl for one out of three subjects. These findings are discussed in terms of their clinical and behavioral importance, with specific reference to Physiotherapy.

abstract: Thesis

abstract: Master of Science (MS)


title: Thermal Modelling of Laser Hyperthermia in the Vicinity of a Large Blood Vessel

contributor:
Wyman, Douglas
Health and Radiation Physics

subject:
thermal modelling
laser hyperthermia
blood vessel

abstract:
In treating cancer with hyperthermia, an understanding of the heat losses associated with the presence of a large functioning blood vessel in or proximal to a
treatment area is needed in order to optimize any protocol. A three-dimensional computer model based on the Bioheat transfer equation (BHTE) has been developed to account for temperature changes in and around functioning blood vessels during laser-induced hyperthermia. The light source is modelled using an approximation to the transport theory solution for an isotropic point source in an infinite homogeneous tissue medium with anistropic scattering. The derived BHTE's for tissue, vessel and blood are solved for temperature using the implicit finite differences method. The validity of the model was tested by comparing predicted temperatures to measured temperatures from a series of dynamic phantom studies using two vessel diameters and three flow rates. Large experimental temperature variations were observed and increased proportionally with increasing thermal gradients. The model consistently over-estimates (~ 1-2C) absolute temperatures close to the source and under-estimates (~ 1-2C) them far from the source. This could be due to uncertainties associated with the estimated thermal conductivity and measured optical properties of the tissue material. Both model and experiments show a small convective heat loss due to the presence of a blood vessel. The model predicts that at high flow rates, temperature reductions of 2C or greater are limited to distances less than 0.3 cm from the surface of a 0.144 cm (outer diameter) vessel and less than 0.8 cm from the surface of a 0.40 cm vessel. The vessel has a negligible effect on temperatures at distances greater than ~ 1.75 cm. The predicted temperature change due to blood flow and the measured change agree to within experimental errors. There was better agreement with the larger diameter vessel.

abstract: Thesis

abstract: Master of Science (MS)


title: Statistical Analysis of a Controlled Clinical Trial in Patients with Metastic Bone Pain

contributor: Viveros-Aguilera Statistics

subject:
statistical analysis
controlled clinical trial
metastic bone
metastic bone pain

abstract: The analgesic effect of 600 mg and 1500 mg of a pain killing drug to metastatic bone pain, and associated side effects, were assessed. The experimental design was a double-blind cross over clinical trial involving 44 patients known to suffer from metastatic bone pain. Each patient received the active drug in one of two dosages and the placebo in a random order, each lasting about 14 consecutive days. The data consisted of daily measurements of several pain and side effect variables. A few covariates were available. It was found that the patient and the investigator achieved a high degree of agreement on the blinded preference of the active drug to the placebo. A multivariate analysis of variance (MANOVA) on three different summary scores (mean, median, trmean) calculated on the daily measurements for which the patient received the active drug and on those for which the patient received the placebo was conducted. It was found that for the group of pain variables the order of application and the treatment do not have a significant effect marginally, but that they interact significantly. Variation between subjects was also significant. For the group of side effect variables, however, only significant variation between subjects was found. This suggests that the drug does not have noticeable overall side effects. To account for correlations among the response measurements within each patient, the methodology of generalized estimating equations was used to assess the significance of the effects of the predictors. Although the results are less reliable as they depend on the asymptotic behaviour of statistics, it was found that regardless of the level of correlation within patient response measurements, only the interaction of order of application with treatment has a significant effect on each of the pain variables. All the statistical analyses were carried out using Minitab, SAS, Matlab and Splus.

abstract: Thesis

abstract: Master of Science (MS)


title: Characterization of Musashi-1 in Pediatric Group 3 Medulloblastoma

title: Musashi-1 in Group 3 Medulloblastoma

contributor:
Singh, Sheila K
Biochemistry and Biomedical Sciences

subject: Musashi-1

abstract: Pediatric medulloblastoma (MB) is the most common solid malignant brain neoplasm, with group 3 (G3) MB representing the most aggressive subgroup. Despite MYC amplification representing an independent poor prognostic factor in G3 MB, efforts to target the MYC pathway have met with limited therapeutic success. As such, alternative mediators of G3 MB continue to be sought. The RNA binding protein and neural stem cell determinant Musashi-1 (MSI1) has been implicated in a number of adult stem cells in various organs (e.g., brain, gut, ovaries/testes) with mounting evidence that MSI1 is an essential regulator of cancer stem cells (e.g., brain, gut, lung).  Early studies in MB have shown MSI1 to be essential for tumour maintenance, however the direct interactions and specific mechanisms conferring tumours with high MSI1 expression (i.e., G3 MB) are yet to be determined. Here, I show MSI1 is an essential moderator of G3 MB in both a MYC amplified and p53 mutated (MP) mouse model of G3 MB and patient-derived xenograft (PDX) models. MSI1 inhibition resulted in an abrogation of tumour initiation in both models, translating to a significantly prolonged survival. To determine how MSI1 regulates the post-transcriptional landscape of human G3 MB, an unbiased multiplatform approach was undertaken, using enhanced cross-linking and immunoprecipitation (eCLIP), and differential analyses post-MSI1 inhibition at the transcriptome-, proteome-, and translatome-wide scale, revealing MSI1's key role in moderating G3 MB-associated cancer driving genes. In summary, employing innovational multi-platform integrative approach to stem cell cancer biology, I show the neural RNA binding protein MSI1, an essential master stem cell regulator, is hijacked from its normal neural developmental function to orchestrate the aberrant translational landscape of G3 MB.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Brain tumours are the leading cause of childhood cancer death with medulloblastoma (MB) representing the most frequent malignant childhood brain tumour. Analysis of the data retrieved from multiple genetic studies of MB, we have determined that there are 4 genetic subgroups of MB: Wnt, Shh, Group 3 (G3) and Group 4 (G4). The subgroup with the worse prognosis is Group 3, and unique to this subgroup is the overproduction of the MYC gene products (i.e., MYC amplification). In fact, MYC amplification alone is associated with a poor prognosis in these children. As such many researchers and clinicians have been working together to find a way to target MYC. Although many pre-clinical experimental studies have cured MYC-amplified G3 MB using gene-targeting therapy, these results unfortunately have not translated into early clinical trials. Therefore, alternative targets that mediate the aggressiveness of MYC-amplified G3 MB is being sought. As cancer stem cells (CSC) have been implicated in tumour development and maintenance, a gene worthy of investigation in a neurodevelopmental tumour such as MB, is Musashi-1 (MSI1). MSI1 protein has been identified in high levels in many human cancers, been observed to play a crucial role in promoting normal stem cell features, and is also implicated in driving cancer. The protein that the MSI1 gene produces binds to genes and modifies them to either stabilize or destabilize their path to becoming a protein. By manipulating MSI1 in both NSC and MB CSC, I will observe how these cells either display greater or less cancer associated features. Further, with a new technology allowing researchers to identify MSI1 binding sites, we aim to determine how MSI1 modifies cancer causing and normal neural stem cell genes. Moreover, I will be studying both the gene-, pre-protein- and protein-level changes after experimentally manipulating MSI1 gene levels to tease out its’ main cancer associated function. Altogether, we found a core list of genes that MSI1 modulates with functional significance giving us clues for a therapeutic targeting strategy for G3 MB.


title: Continuation Ratio and Generalized Estimating Equation Analysis of a Longitudinal Asthma Study

title: Statistical Analysis of a Longitudinal Asthma Study

contributor:
Aguilera, Roman
Statistics

subject: asthma

subject: longitudinal asthma study

subject: longitudinal study

subject: continuation ratio

subject: generalized estimating equations analysis

abstract: Two randomized controlled trials were conducted to find out whether a new treatment for asthma has a significant effect on the patients. These were multi-center trials with a parallel design, the control arm receiving a Placebo. The data were collected over a period of about 20 days before administering the intervention and for almost 80 days after the intervention. Thus, each patient has many observations recorded, making the data longitudinal. The data are summarized using first descriptive statistics and graphical displays. Then, a continuation ratio model with a lagged covariate to account for the longitudinal aspect is used to model the data. Finally, Generalized Estimating Equations methods are used. These methods have acquired popularity in recent years to account for longitudinal correlation structures. To apply the continuation ratio, the data have to be appropriately restructured. Then, the logistic regression is used to model the symptoms. The results of this procedure show that the treatment is statistically significant. However, the goodness of fit tests show that the model is inadequate. This issue is explored in the last subsection of Chapter 3. Using Generalized Estimating Equations to analyze the number of times rescue medication was used, we concluded that there is no statistically significant difference between the Active and Control groups. However, we noticed that the use of rescue medication decreased with time from the start of treatment.

abstract: Thesis

abstract: Master of Science (MS)


title: Movement Preparation and Down Syndrome: The Costs and Benefits of Advance Information

subject:
movement preparation
Down syndrome
cost and benefit
advance information

abstract: This study attempts to resolve to what extent individuals with Down syndrome benefit from advance information provided visually, versus the same information provided verbally when performing a manual aiming task. Adults with Down syndrome and undifferentiated developmental handicaps, as well as control subjects without a developmental handicap, performed manual aiming movements to targets 10.5 cm. away. On a particular trial, subjects were cued about the specific movement either visually or verbally. The cue provided either 50% or 80% certainty. Nonhandicapped control subjects initiated and completed their manual aiming movements more quickly than subjects with mental handicaps. As well, individuals with Down syndrome were found to be slower and more variable in reaction time than individuals in the other mentally handicapped group when valid information was provided verbally but not when the cue was provide visually. These results provide support for the Elliott and Weeks (1990) model of biological dissociation. Specifically, the atypical hemispheric lateralization for speech perception exhibited by individuals with Down syndrome results in a disruption in communication between functional systems responsible for the processing of verbal langauge, and the organization of complex movement.

abstract: Thesis

abstract: Master of Science (MS)


title: Acid-Base Regulation in the Bullfrog (Rana catesbiana) Following Acid Infusions and Enforced Submergence

contributor:
McDonald, D. G.
Biology

subject:
acid-base regulation
bullfrog (rana catesbiana)
acid infusion
enforced submergence

abstract:
This study examined the acid-base and ionoregulatory responses by the skin and kidney of adult bullfrogs (Rana catesbiana) during
recovery from non-respiratory acidoses. Acidosis was induced by intravascular infusions of HCl (3,000 uequiv/kg), or NH4Cl (4,000 uequiv/kg), or by 45 min enforced submergence. Infused acids were immediately buffered by the extracellular fluids (ECF) and moved rapidly into the intracellular compartment. Clearance of the acid load was slow (> 24 h post-infusion) and only in NH4Cl loaded frogs was the full amount cleared within 5 days. Excess acid was excreted primarily by increased renal NH4+ effluxes. The skin contributed very little to the net acid excretion; instead large "base" losses ("acid" uptake) occurred. Acid infusions also resulted in large ion losses and elevated water uptake across the skin, with electrolytes and water moving down chemical gradients. Frogs infused with HCl died within 96 h; NH4Cl loaded frogs all survived.Forced submergence resulted in a severe lactacidosis which was corrected in 12 h by a combination of renal/cutaneous acid excretion (9:1 ratio) and metabolic utilization of lactate and H+ (~ 95% of excess acid load). Acid excretion occurred primarily as NH4+ efflux by the kidney and skin. A 1:1 exchange of Na+ influx/NH4+, efflux across the skin was found (r = 0.94; P < 0.01) when Jin Na+ was elevated over basal levels (30-40 uequiv/kg·h). Lactate and net acid effluxes by the skin and kidney diminished by 24 h post-disturbance and accounted for 4 to 6% of the total estimated load to the animal. All frogs survived the diving protocol. Restoration of acid-base state in acidotic bullfrogs by ECF and non-ECF mechanisms, as well as the renal and cutaneous responses to the acidosis, is discussed and compared to that of other vertebrates. It is concluded that anurans, and the bullfrog in particular, are poor regulators of acid-base state but instead are very tolerant to marked disturbances of acid-base balance.

abstract: Thesis

abstract: Master of Science (MS)


title: Cerebral Specialization for Speech and Complex Verbal Movements in Down Syndrome

contributor:
Elliott, Digby
Human Biodynamics

subject:
cerebral specialization
speech and complex oral verbal movement
down syndrome

abstract:
The neurobehavioural organization of speech perception and production in persons with Down Syndrome (DS) is still not clearly understood. The current study investigated the cerebral specialization for speech production using a mouth asymmetry paradigm. In right handed, non-handicapped subjects the mouth asymmetry methodology has shown a facilitation on the right side of the mouth during expressive speech. The right mouth asymmetry is believed to reflect the dominance of the left hemisphere for speech production (Graves, Goodglass & Landis, 1982). In the present study the lateralization for the production of speech was investigated in 10 right handed participants with Down syndrome and 10 non-handicapped subjects. The results indicated that a tendency for a right mouth advantage (RMA) at the initiation and end of speech production occurred in both subject groups. Surprisingly, the degree of asymmetry did not differ, suggesting that the focal representation of speech production is lateralized similarly in both subject groups. Additionally, a high proportion of verbal errors were made by individuals with DS. These results are consistent with the model of biological dissociation (Elliott & Weeks, 1993), which asserts that individuals with DS are impaired on verbal-motor tasks due to the functional separation between speech perception centers in the right cerebral hemisphere, and speech production centers in the left cerebral
hemisphere.

abstract: Thesis

abstract: Master of Science (MS)


title: A Comparative Analysis of Five Instruments to Measure Control of Asthma

contributor:
Walter, S. D.
Statistics

subject:
comparative analysis
asthma
five instruments to measure asthma
control asthma

abstract: The control of asthma is a very important part of an asthmatic's life. Decreasing control can lead to asthma attacks, which can be fatal. For this reason, the researchers have set out to create an instrument to measure control of asthma, and have suggested five possible instruments. Before an instrument can be used, it must be shown to be reliable, valid, and responsive. Reliability will be shown using various intraclass correlation coefficients, depending on the model being used for the data. Construct validity will be shown by how well the instrument's correlation coefficients with other instruments correspond to a priori predictions. Responsiveness will be shown by three methods, t tests comparing the change in changers and stable subjects, a responsiveness index, and Receiver Operating Characteristic (ROC) curves. All five instruments are shown to be highly reliable. No conclusions can be drawn as of yet about the validity, as the a priori predictions have yet to made. For all three methods of assessing responsiveness, the five instruments were ranked identically. In choosing the best instrument, no final decisions can be made, as validity has yet to be shown, but at this time it appears as though the simplest instrument (involving only five questions on the patient's asthma symptoms asked at a visit to a clinic) is also the best as it has high reliability and is highly responsive.

abstract: Thesis

abstract: Master of Science (MS)


title: Digital Signal Processing of Neurocardiac Signals in Patients with Congestive Heart Failure

title: DSP of Neurocardiac Signals in Patients with CHF

contributor:
Kamath, Markad
Electrical and Computer Engineering

subject:
digital signal processing
neurocardiac signals
congestive heart failure

abstract: Recent work has found that a frequency domain and time domain analysis of the heart rate variability signals can provide significant insights into function of the heart in healthy subjects and in patients with heart disease. Patients with congestive heart failure are an important clinical health issue and it is hoped that this work will contribute towards gaining knowledge of this debilitating pathological condition. Our laboratory has recently acquired more than three thousand 24-hour ECG tapes recorded during called Study of Left Ventricular Dysfunction (SOLVD). The SOL VD trial was conducted between 1987-1990 to test the efficacy of a medication called, Enalapril, to treat patients with heart failure. There were an equal number of patients with (group A) and without overt heart failure (group B). The work reported in this thesis describes the development of a hardware and software framework used to analyze the ECG signals recorded on these tapes. Primary objective of this work was to develop and test a system which would assist in analyzing the above tapes so as to examine if there are differences between two groups using the HRV parameters from both frequency and time domain. The research was conducted in three steps: Hardware design, software and algorithm development and finally the validation phase of the design, to test the usefulness of the overall system. The tapes were replayed on a tape recorder and the ECG was digitized at a rate corresponding to 500 samples/second. Labview software was invoked for this task. Secondly a set of algorithms were developed to perform QRS-detection and QT-interval identification. The detection algorithms involved placing critical ECG fiducials onto the ECG waveform through the use of a trained model. The model construction used patient specific pre-annotated data coupled with statistical and genetic algorithm techniques. The beat-to-beat HRV signal was thus generated using the annotation data from the ECG. Frequency domain indices were obtained using power spectral computation algorithms while time domain statistical indices were computed using standard methods. QT-interval algorithms were tested using a set of manually and automatically tagged set of beats from a sample of subjects. For the third part of this research, i.e. validation phase, we set up a test pool of 200 tapes each from patients with overt heart failure and with no heart failure, recorded at the baseline before the subjects entered the study. This phase of the study was conducted with the help of a statistician in a blinded fashion. Our results suggest that there is significant difference between frequency domain and time domain parameters computed from the HRV signals recorded from subjects belonging to group A and group B. The group A patients had a lot of ectopic beats and were challenging to analyze. These results provide a confirmation of our analytical procedures using real clinical data. The QT-analysis of the ECG signals suggest that automatic analysis of this interval is feasible using algorithms developed in this study.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: A Real Time Fault Detection and Diagnosis System for Automotive Applications

contributor:
Habibi, Saeid Dr.
Mechanical Engineering

subject: neural network, machine learning, data acquisition, embedded systems, signal processing

abstract:
Since its inception in the nineteenth century, the Internal Combustion Engine (ICE) remains the most prevalent technology in transportation systems to date. In order to minimize emissions, it is important that ICE is operated according to its optimized design conditions. As such, condition monitoring and Fault Detection and Diagnosis (FDD) tools can play an important role in detecting conditions that would affect the operability of the engine. In this research, different signal-based Fault Detection and Diagnosis (FDD) techniques are researched and implemented for fault condition monitoring of ICE. The implementation of prognostics for the engine in an automated form has important consequences that include cost savings, increased reliability, reduction of GHG emissions, better safety, and extended life for the vehicle.
In this research, in order to carry out FDD onboard, a low-cost and flexible internet-based data-acquisition system (DAQ) was designed and implemented. The main part of the system is an embedded hardware running a full desktop version of Linux. This sensory system leverages the positive aspects of both real-time and general-purpose architectures to ensure engine monitoring at high sampling rates. Unlike other commercial DAQ systems, the software of this device is open-source, free of charge, and highly expandable to suit other FDD applications.
In addition to data collection at high sampling rates, the FDD system includes advanced FDD strategies. The Fault Detection and Diagnosis strategies considered use a combination of Fourier Transforms (FT), Wavelet Transforms (WT), and Principal Component Analysis (PCA). Meanwhile, Fault Classification was carried using Neural Networks consisting of the Multi-Layer Perceptron (MLP). Three strategies were comparatively considered for the training of the Neural Network (NN), namely the Levenberg-Marquardt (LM), the Extended Kalman Filter (EKF), and the Smooth Variable Structure Filter (SVSF) techniques. The proposed FDD system was able to achieve 100% accuracy in classifying a set of engine faults.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Witness to Responsibility: AIDS Narratives and the Question of Reading

contributor:
Clark, David
English

subject:
responsibility
AIDS
AIDS narrative
reading

abstract: The current age of AIDS has seen the emergence of a body of literature whose goal it is to make AIDS, its multifarious meanings and overwhelmingly devastating effects, not only visible, but also somehow comprehensible to as many people as possible. Much of this literature is produced by gay men and women, who are among the most intimate witnesses to the AIDS crisis. This thesis explores three AIDS narratives as manifestations of the writers' responsibilities as witnesses to and of HIV and AIDS. The first chapter examines Amy Hoffman's Hospital Time as an act of mourning through which she seeks to shape the reader as a mourner. Mourning is a responsibility, I argue, that Hoffman does not allow the reader to refuse. Reading Derek Jarman's diary Modern Nature through Jacques Derrida's reading of Friedrich Nietzsche's Ecce Homo in The Ear of the Other, Chapter Two theorizes the activist potential of the "signature." Through his garden, Jarman demonstrates how he produces a signature for his dead friends, enabling them to "live" eternally. With this signature Jarman sculpts the reader's own signature, the signature through which he intends for the reader to grant him "life" after death. It is the exposition of the possibility of life through the signature that Jarman understands as his responsibility as a witness to AIDS. And finally, Chapter Three examines Dale Peck's Martin and John as a theorization of the "middle ground" between dominant culture's representations of HIV and AIDS and AIDS activist representations. As a metafictional text, the structure of the novel requests the reader to interpret and negotiate recursively these representations. It is this very request that Peck illustrates as his responsibility. Thus, the writers' foremost responsibility, I propose, is to reproduce in the reader what the writer understands as his or her own responsibilities in witnessing AIDS. The reader must become the witness.

abstract: Thesis

abstract: Master of Arts (MA)


title: Physico-Chemical, Minearlogical and Micromorphological Studies on Alfisol and Spodosol Profiles from Southern Ontario, Canada

contributor:
Bunting, B. T.
Geography

subject:
physico-chemical study
micromorphological study
mineralogical study
alfisol profile
spodosol profile

abstract: The relationship between soil properties and micromorphological features was studied in six Alfisol and six Spodosol profiles from Southern Ontario. The total porosity of the soil material was largely related to the size, shape and conformation of the soil voids in thin sections, while the differential development of plasma fabric could be used to discern a sequence of degrees of weathering which was also expressed by various mineralogical and physico-chemical indices. The relative proportions of soil constituents in thin sections was successfully used to indicate the existing textural discontinuities in five of the profiles studied. The elementary structure of soil thin sections is considered the most important micromorphological feature in the investigation of the degree of B horizon development in both Alfisol and Spodosol profiles.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Condition of the Working Man at the Beginning of the Sixteenth Century

subject:
sixteenth century
working man
condition

abstract:
Thesis
Master of Arts (MA)


title: The Umland of Hamilton, Ontario

subject:
umland
hamilton, ON
ontario
geography

abstract: Every city possesses and umland, an area adjacent to the city, within which economic, cultural, and social activities are focused on that city. The size of the umland is determined chiefly by two factors, the size of the city, and its location. A large city usually will have a large umland, but if it is situated in an area of urban concentration, the extent of the umland will be limited through competition. Hamilton is a city such as this. Near it is Toronto, a large and influential city which restricts Hamilton's regional development. Closer are the smaller cities of Guelph, Galt, Brantford and St. Catherines, all of which have their own umlands, and all of which compete with Hamilton. The term umland implies an interrelationship between the city and the region. The city performs services for the region, and distributes goods to it. In turn, the region supplies provisions for the urban market, and workers and buyers for its industrial and commercial enterprises. This relationshup may or may not be close. Hamilton is an industrial city, with little dependence on the region. However, the region looks to the city to supply some of its needs. It is the purpose of this thesis to show the relationship between Hamilton and its umland, and to explain some of the factors which determine the extent of that umland.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: Amnesic and Disinhibitory Effects of Electroconvulsive Shock

contributor:
Vanderwolf, C. H.
Psychology

subject:
amnesia
disinhibitory effect
electroconvulsive shock

abstract: Electroconvulsive shock (ECS) produces a loss of memory for the immediately preceding period, but also produces non-amnesic effects which seriously complicate the interpretation of behavioral results following convulsions. The results of the present investigation indicated that the retrograde amnesia produced by ECS is probably slight, but appears enhanced in passive-avoidance tasks and diminished in aversively-motivated tasks requiring movement, because of a concomitant impairment of movement-inhibiting mechanisms. If this interpretation is valid, it is extremely difficult to make quantitative estimates of the degree or temporal extent of the retrograde amnesia induced by ECS in animals. It may be possible, however, to separate memory mechanisms from movement-inhibiting mechanisms with procedures involving more localized effects upon the brain.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Damage Layer Produced in Ion Bombarded Silicon

contributor:
Kelly, R.
Metallurgy and Materials Science

subject:
damage layer
ion bombarded silicon
silicon

abstract: In this thesis a study is made of the damage layer (as defined by its solubility in a HF-H2o2, or concentrated HF solution) produced by ion bombardment of Si. This thesis is concerned with not only the layer but also its usefulness in the study of radiation damage itself. The layer is examined with respect to the adverse effects it has upon the anodic oxidation and stripping technique, to the dose of incident ions required to produce it (ie the threshold dose), and to its relationship to the amorphous layer which has been observed with ion bombardment of Si. Annealing of the damage has been approached from two points of view. First the temperature dependence of the threshold dose is used to obtain information about the annealing of the damage that occurs between the formation of a discrete damage zone and the formation of a layer. Secondly using gas release of the radioactive Kr85 the annealing of the fully formed amorphous damage layer is followed. The solubility of the damage layer in a HF-H2o2 solution is shown to be a very useful tool in the study of radiation damage. Firstly it provides a convenient means of obtaining the mean range of the damage distribution as a function of incident ion energy. Secondly it is used to obtain the threshold dose for the formation of the damage layer, and thirdly it is used in the gas release experiments to give more detailed information about the Kr85 motion.

abstract: Thesis

abstract: Master of Science (MS)


title: Analysis of Growth Rings in Black Spruce (Picea mariana) in Relation to Site and Climatic Factors

contributor:
Radforth, N. W.
Biology

subject:
tree rings
growth rings
black spruce
climatic factor

abstract: The annual earlywood, latewood and total radial growth in black spruce from organic and mineral soils of varying depths, composition, ad moisture regimes of three locations in Ontario were investigated. Growth in relation to site, temperature, and precipitation was assessed. Statistical analyses of the radial width increments expressed as percentages of trend over thirty years' growth, showed significant crossdating. Total annual and earlywood increments are correlated with mean March-April and March temperature; latewood increments are not. There is no relationship between growth and precipitation. These findings hold for trees from organic and mineral soil sites up to approximately five hundred miles apart. It is concluded that spring mean temperature is independent of site or other climatic factors, and results suggest that spring temperature indirectly controls radial growth. Primary direct controls are presumably internal, i.e. physiologic and genetic.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: An Analysis of a Set of Medical Data with Missing Observations

subject:
medical data
observations
analysis

abstract:
The efficacies of two tranquilizers and a placebo in reducing tension and related complaints were studied at three clinics over a period of six weeks. There was a considerable amount of missing data in this drug trial. The purposes of this project were:
(1) To estimate the missing values by the regression technique and
(2) to analyse the data by the multivariate analyses of variance method
A significant time trend in changes of severity during the six-week period was found in all three clinics. The predominant trend was linear. But quadratic and cubic trends were also found in some clinics. As far as effectiveness of tranquilizers was concerned there was no conclusive answer. In two clinics, the tranquilizers were not proved to be better than the placebo. In the third clinic, however the 2 active drugs were significantly different from the placebo. This inconsistant result of drug effects among the 3 clinics might be due to
(1)
non-random allocation of subjects to the clinics and
(2)
the fact that a large proportion of subjects failed to complete the study

abstract: Thesis

abstract: Master of Science (MS)


title: Mixing and Energy Relationships in a Flocculation Unit

contributor:
Murphy, K. L.
Chemical Engineering

subject:
energy relationship
flocculation unit

abstract: The effects or energy input variation on the mixing obtained in a laboratory flocculation unit were studied. The main parameter was the size and shape or paddles used to induce the mixing. A variation in paddle geometry produced a variation in energy input. The effect of baffles was studied and the effect of flocculator geometry was considered by comparing two different length to width ratios tor a single tank. Theoretical models were used in an attempt to describe a flocculation unit by comparing the experimental tracer output with the predicted theoretical output. Some generally accepted design criteria tor full-scale flocculation units were also compared with experimental results.

abstract: Thesis

abstract: Master of Engineering (ME)


title: Four Essays in Health Economics

contributor:
Sweetman, Arthur
Economics

subject:
health economics
payment reform
laboratory utilization

abstract:
This thesis addresses health-policy relevant questions regarding quantity and quality of service delivery in primary healthcare using health administrative data from the province of Ontario. It is comprised of four chapters that explore the following questions: (1) What is the impact of switching from an enhanced fee-for-service (EFFS) payment model to a blended capitation payment model on the specialist referral rates of primary care physicians? (2) What are the rates of inappropriate laboratory testing in the province of Ontario? (3) What are the costs and determinants (physician and practice characteristics) of these inappropriate tests? (4) What is the impact of primary care payment structure on the quantity (number and cost) and the quality (appropriateness) of clinical laboratory testing?
Fee-for-service (FFS) payment systems give physicians an incentive to treat patients on the margin of being referred, whereas in capitation systems physicians do not have a financial incentive to treat such marginal patients. Chapter 1 empirically examines how these two payment systems affect referral rates. The results show an increase in specialist visits upon a switch from an EFFS model to a blended capitation model when the physician is listed as the referring physician in the data, but no change in total specialist visits for these physicians’ patients. This change is not observed immediately upon switching payment models. Physicians paid by blended capitation who practice in an interdisciplinary health team have fewer specialist visits per rostered patient compared to EFFS physicians, despite an increase in their patients’ specialist visits after joining the interdisciplinary team.
Using a definition of inappropriateness that quantifies ordering clinical laboratory tests too often or too soon following a previous test, Chapter 2 examines the rates of inappropriate laboratory testing for nine selected analytes in Ontario. The chapter finds that the percentage of inappropriate tests ranges from 6% to 20%. Moreover, between 60% and 85% of the time, the physician ordering an inappropriate test is the same physician who ordered the previous test. The findings also show that specialists are more likely than primary care physicians to order repeat tests too soon.
Chapter 3 examines the costs and determinants associated with the rates of inappropriate laboratory utilization. The associated costs of inappropriate/redundant laboratory testing for the selected analytes ranges between 6 – 20% of the total cost of each test.  Statistical analyses of the association of physician and practice characteristics with inappropriate testing are done using a logit model. Conditional upon the variables within the model, male physicians, physicians trained outside of Canada, older physicians, and a younger patient population are all shown to be associated with less inappropriate testing. Primary care physicians in group practices and in payment models with pay-for-performance (P4P) incentives are less likely to order inappropriate tests and specialist physicians are twice as likely to order inappropriately compared to FFS primary care physicians. Differences in physician, practice and patient characteristics, however, explain only a small amount of the variation in inappropriate utilization.
Chapter 4 examines how physicians’ laboratory test ordering patterns change following a switch from an FFS payment model enhanced with P4P to a blended capitation payment model, and the differences in ordering patterns between traditional staffing and interdisciplinary teams within the blended capitation model. Using a propensity score weighted fixed-effects specification to address selection, the chapter estimates that a mandatory switch to capitation would lead to an average of 3% fewer laboratory requisitions per patient. Patients’ laboratory utilization also becomes more concentrated with the rostering physician. More importantly, using diabetes-related laboratory tests as a case study, physicians order 3% fewer inappropriate/redundant tests after joining the blended model and 9% fewer if they joined an interdisciplinary care team within the blended model.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Investigations of Novel NxSy Technetium and Rhenium Chelants

contributor:
Bell, Russell
Lock, Colin
Chemistry

subject:
novel NxSy
technetium
rhenium chelant

abstract: This thesis describes the synthesis and complexation of amino acid based chelants for technetium and rhenium. All of the chelates were of the NxSy type. An initial N2S2 diamido dithiol peptide of the type mercaptoacetic acid-serine-cysteine was synthesized and coordinated with both rhenium and technetium. The complexes were analysed by NMR spectroscopy and found to retain the benzyl moieties. Syn and anti diastereoemers were produced with one conformation preferred over the other. This was not true of another chelant RP294 supplied by Resolution Pharmaceuticals. The N2N1'S1 chelant consisted of dimethyl-glycine-serine-cysteineglycine and was a novel variation of the N2S2 tripeptide used initially. The coordination of this N3S chelant to technetium resulted in the formation of equal 1:1 quantities of diastereomers. Analysis was done by NMR spectroscopy and electrospray mass spectrometry. The two diastereomers were found to slowly interconvert and a mechanism for the interconversion proposed. The radiopharmaceutical RP128 (dimethylglycineserine-cysteine-glycine-threonine-lysine-proline-proline-arginine), of which the RP294 is the chelating portion, was coordinated to technetium. Analysis of the bifunctional chelant and its coordination complex by NMR spectroscopy demonstrated that the targeting portion of the molecule was unaffected by the technetium. Two diastereomers of the TcO(RP128) complex were found, as seen for the chelating portion of the molecule, TcO(RP294).

abstract: Thesis

abstract: Master of Science (MS)


title: Predicting Walking Intentions and Behaviour among Individuals with Intermittent Claudication: The Role of Pain within the Theory of Planned Behaviour

title: Walking Determinants and Intermittent Claudication

contributor:
Bray, S. R.
Kinesiology

subject:
walking intention
intermittent claudication
pain
theory of planned behaviour

abstract: After looking in the vault copies, the Digitization Centre has determined that page vi is a missing page and may be a printing error. -Digitization Centre

abstract: This study aimed to improve understanding of walking exercise among individuals with intermittent claudication. Using a prospective design, Ajzen's (1985, 1991) theory of planned behaviour was applied to examine psychosocial determinants of walking exercise. In addition, measures of barrier self-efficacy were explored as determinants of behaviour and perceived pain intensity was examined as a moderator of the intention-behaviour relationship. Ninety-four participants (n = 33 female) completed baseline measures of attitudes, subjective norms, perceived behavioural control, and intentions to engage in walking exercise. Additional measures of pain-related barrier self-efficacy and barrier self-efficacy regarding walking exercise were obtained and the Borg CR1 0 Pain Scale (Borg, 1998) was used to assess perceived pain intensity during walking. Participants were contacted weekly by telephone over four consecutive weeks and asked to recall their walking exercise and associated perceived pain intensity for the preceding seven-day period. Attitudes, subjective norms and perceived behavioural control contributed significantly to a multiple regression model predicting 67% of the variance in walking intentions. Intentions and perceived behavioural control explained 34% of the variance in walking exercise; however, pain-related barrier self-efficacy and barrier self-efficacy did not explain additional variance in behaviour and perceived pain intensity failed to moderate the intention-behaviour relationship. Findings support the theory of planned behaviour for predicting walking intentions and exercise among individuals with intermittent claudication, and suggest that pain cognitions as measured in this study do not play a role in determining walking.

abstract: Thesis

abstract: Master of Science (MS)


title: Synthesis and Characterization of Pyrene Labeled Poly(N-Isopropylacrylamide-Co-N-Acryloyl-L-Valine) Copolymers

title: Synthesis and Characterization of Pyrene Labeled Copolymers

contributor:
Winnik, F. M.
Chemistry

subject:
synthesis
pyrene labelled copolymers
copolymer

abstract: The Digitization Centre has determined that pages x, 30 and 106 are not in this thesis or the vault copy.

abstract: Pyrenebutylamide-labeled poly(N-isopropylacrylamide-co-N-acryloyl-L-valine) copolymers have been prepared by two different methods and their physicochemical properties have been compared. One sample was prepared via copolymerization of N-isopropylacrylamide (NIPAM), and N-acryloyl-valine (NAV) with N-[4-(1-pyrenyl)butylacrylamide], the other by post-modification of poly(N-isopropylacrylamide-co-N-acryloyl-L-valine-co-N-acryloxysuccinimide) copolymer with pyrenebutylamine hydrochloride. The polymers were characterized by 1H NMR and FTIR spectroscopy, Differential scanning calorimetry and light Scattering. Though the use of fluorescence spectroscopy several differences between the two types of copolymers were detected. By comparing the extent of pyrene excimer emission and pyrene monomer emission from solutions of the two polymers, it was concluded that the copolymer obtained by direct copolymerization (method 1) had an inherent ''blocky" microstructure, while the copolymers obtained by the post-modification route presented a more random microstructure. Intrapolymeric interaction exists in solutions of low copolymer concentrations. At higher concentrations both inter-and intrapolymeric interactions coexist. The presence of a number carboxylic groups in the PNIP AM chain significantly modifies the conformation properties of the copolymers, compared to poly(N-isopropylacrylamide). The copolymers contract and expand in response to external conditions such as pH and temperature. Their Lower critical solution temperature (LCST) changes with pH. The interactions between polymers and fluorescence quenchers were investigated. The quenching results reveal that hydrophilic cationic quenchers interact strongly with the randomly labeled-copolymer. Hydrophobic cationic species interact strongly with ''blocky" pyrene labeled copolymer. Anionic quencher interacts quite weakly with both copolymers owing to electrostatic repulsion.

abstract: Thesis

abstract: Master of Science (MS)


title: A Study of Precipitate Morphologies in Cu-Zn and Cu-Zn-Sn Alloys

contributor:
Purdy, G. R.
Metallurgy

subject:
precipitate morphology
copper
zinc
tin
alloy

abstract: The Digitization Centre has determined that page 49 was not published with the original copies of this thesis.

abstract: The validity of current theories of precipitate morphology is dependent on the microscopic nature of the precipitate-matrix interface. It is the purpose of this thesis to investigate, by electron microscopy interfacial structure and mobility in precipitation reactions pertaining to these theories. In particular the B->a Widmanstatten reaction in 60:40 brass is investigated and compared with the B->y reaction in a Cu-Zn-Sn alloy.

abstract: Thesis

abstract: Master of Science (MS)


title: Cessation of a 12-Month Body-Weight Supported Treadmill Training Program: Effect on Functional Ambulation and Health-Related Quality of Life in Individuals with Incomplete Spinal Cord Injury

title: Cessation of BWSTT: Walking and HRQL in Indivuduals with SCI

contributor:
McCartney, N.
Human Biodynamics

subject:
functional ambulation
quality of life
spinal cord injury
treadmill training

abstract: The purpose of this study was to determine the effects of cessation of a 12-month thrice-weekly body-weight supported treadmill training (BWSTT) program on functional ambulation and aspects of health-related quality of life (HRQL) in individuals with incomplete SCI. Twelve men and women (aged 22-55) with chronic (> 1 year post-injury) incomplete SCI (ASIA B or C) returned for follow-up (FOL) testing 37 weeks (SD 2.1) following their final scheduled BWSTT session. Functional ambulation was compared based on: i) required percentage of body-weight support (%BWS) on the treadmill, ii) preferred treadmill speed and iii) overground walking. Evaluation of HRQL included measures of: i) satisfaction with life, ii) perceived ability to perform activities of daily living (ADL), iii) perceptions of health, and iv) depressive symptomology. Participants were invited to participate in once-weekly BWSTT and twice-weekly fitness training during the FOL period (37 sessions); the actual number of BWSTT sessions attended was only 11.6 (range 0-29) and the total days of exercise was 29.1 (range 0-75). The 12-month BWSTT program resulted in a decrease in the required %BWS (73±10% to 19±12%; p<.01), an increase in treadmill speed (0.5±0.3 to 1.4±0.8 km/h; p<.01), improved overground walking in 4 individuals, and improved group satisfaction with life (p<.05). At FOL, %BWS increased to 35±14% (p<.01), but was still less than at pre-training (p<.01). There were no differences between 12-month and FOL scores on any HRQL-related measures. High exercise adherence during the FOL period had a strong correlation with a positive percent change in perceived ability to perform ADL (r = .70; p<.05), as well as non-significant trends with positive percent change in perceptions of health and negative percent change in depressive symptomology (r = .49; p=.13 and r = .51; p=.ll, respectively). Therefore, even with very limited access to the BWS treadmill, much of the improvement in treadmill walking ability and satisfaction with life following long-term BWSTT in individuals with incomplete SCI can be retained for at least 8 months. Continued exercise participation, however, may contribute to maintain or further improve aspects of HRQL in this population.

abstract: Thesis

abstract: Master of Science (MS)


title: Palaeomagnetic Evidence for Anti-Clockwise Rotation of Rouyn-Noranda Structural Block, Quebec, Canada

title: Palaeomagnetic Rotations in the Abitibi Belt

contributor:
Hale, Christopher
Geology

subject:
palaeomagnetic evidence
anti-clockwise rotation
rouyn-noranda block
quebec, Canada

abstract:
The Rouyn-Noranda area in the center of the Abitibi subprovince is composed of comparatively unmetamorphosed Archean volcanics of Blake River Group (ERG). Rouyn-Nornada is one of the lozenge shaped structural blocks in the area bounded by the Porcupine Destor Fault (PDF) zone and the Larder Lake Caddilac Fault (LCF) zone. 160 samples were collected from 29 different sites selected to lie in the center of the block, at or near the PDF zone and accross the PDF zone in the neighboring lozenge.
Stable magnetizations have been obtained from the central relatively unstrained parts of the lozenges. These magnetizations show some improvement in precision statistics after structural corrections implying that they are pre-folding and probably Archean in age. Sites along the PDF zone show scattered magnetizations, which do not agree at sample or site level. The Zone I (Sites in the center of the Rouyn-Noranda block) structurally corrected mean direction (D=154.0, I=-95.0, k=19.0, a95 =19.0, N=6 sites) differ from the Zone III (Sites from the center of the adjacent block) mean direction (D=214.0, I=-49.0, k=16.0, a95 =92.0) by 60+/-37° implying that the Rouyn-Norand block have rotated anti-clockwise by 60+/-37° about a vertical axis relative to the adjacent structural block.

abstract: Thesis

abstract: Master of Science (MS)


title: A Study of the Promotion of Convergence in the Calculation of Complex Chemical Plants

contributor:
Crowe, C. M.
Chemical Engineering

subject:
convergence
complex chemical plant

abstract: This thesis is missing page 147 in all printed copies. - Digitization Centre

abstract: Techniques for accelerating the convergence of multi-variable iterative calculations were studied. The study is mainly concerned with iterations which result from the calculation of recycle processes of complex chemical plants. The conditions for convergence and the existence of the solution of linear and non-linear iterations were obtained. Special attention was given to the asymptotic behaviour of the iterations since, in most cases, they approach geometric progression. The convergence of an Alkylation unit simulation was studied by implementation of the "full matrix" technique for accelerating the rate of convergence. The geometric extrapolation technique was described and applied successfully for accelerating the convergence of the calculation of multi-component distillation columns.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Singing the Vila: Supernatural Beings in the Context of their Traditions

contributor:
Colarusso, John
Anthropology

subject: Supernatural Beings; Oral Traditions; Folklore; Bosnia; Croatia; Montenegro; Serbia; Survey

abstract: This thesis presents a critical overview of a supernatural being, the South Slavic vila, as she figures in the oral traditions of Bosnian, Croatian, Montenegrin and Serbian peasants collected in the 19th and early 20th centuries. The thesis returns to the conceptual frame of older primary texts (here titled survey studies) used by comparative scholars and updates this work with the knowledge gleaned from a century of research and theory in the fields of folkloristics and historical anthropology. These materials are presented in a distributive frequency analysis model such as those often employed by the Historical-Geographic school of folklore research, but the study is built on a foundation informed by the insights of Milman Parry and Albert Lord’s researches into the diffusion of oral traditions. These traditions are further refined by focusing on the singers, storytellers and believers who used the vila in an emic manner balanced at a nexus point between artistic innovation and traditional dictates. The data is also further contextualized with a focus on the embedded nature of these cultural expressions and a clear portrait of the contexts surrounding their collection and publication in a wider cultural sphere. The aim of the thesis is to present a comprehensive description of the vila’s role in oral traditions to serve as a primary source for scholars doing comparative or interpretive work, as well as to provide a clearer picture of the contexts of the materials to refine such research. In doing so, this thesis produces a comprehensive method and model that can be applied to other supernatural beings, repatriates oral arts back to their original purveyors by undoing academic silencing of subaltern voices and returns critical context to inherited traditions once stripped of them by romantic academic theories.

abstract: Thesis

abstract: Candidate in Philosophy


title: Vibronic Interaction in Linear Polyatomic Molecules

contributor:
Bader, R. F. W.
Chemistry

subject:
vibronic interaction
polyatomic molecules

abstract: This thesis deals with the weak interaction between the electronic and degenerate vibrational motions in linear polyatomic molecules. Second-order vibronic energy expressions are obtained for triatomic and tetratomic molecules in degenerate electronic states.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Blast Performance Quantification Strategies For Reinforced Masonry Shear Walls With Boundary Elements

contributor:
El-Dakhakhni, Wael
Tait, Michael
Civil Engineering

subject:
Blast Load
Boundary Elements
Dynamic Modeling
Resistance Function
Response limits
Opensees
Damage State
Performance Quantification

abstract:
Structural systems have been evolving in terms of material properties and construction techniques, and their levels of protection against hazardous events have been the focus of different studies. For instance, the performance of the lateral force resisting systems has been investigated extensively to ensure that such systems would provide an adequate level of strength ductility capacity when subjected to seismic loading. However, with the increased occurrence of accidental and deliberate explosion incidents globally by more than three fold from 2004 to 2012, more studies have been focusing on the performance of such systems to blast loads and the different methods to quantify the inflicted damage.
	Although both blast and seismic design requires structures to sustain a level of ductility to withstand the displacement demands, the distributions of such demands from seismic ground excitation and blast loading throughout the structural system are completely different. Therefore, a ductile seismic force resisting system may not necessarily be sufficient to resist a blast wave. To address this concern, North American standards ASCE 59-11, CSA S850-12 provide response limits that define the different damage states that components may exhibit prior to collapse.
      Over the past ten years, a new configuration of reinforced masonry (RM) shear walls utilizing boundary elements (BEs) at the vertical edges of the wall has been investigated as an innovative configuration that enhances the wall’s in-plane performance. As such, they are included in the North American Masonry design standards, CSA S304-14 and TMS 402-16 as an alternative means to enhance the ductility of seismic force resisting systems. However, investigations regarding the out-of-plane performance of such walls are generally scarce in literature which hindered the blast design standards from providing unique response limits that can quantify the different damage states for RM walls with BEs.
        This dissertation has highlighted that some relevant knowledge gaps may lead to unconservative designs. Such gaps include (a) the RM wall with BEs out-of-plane behavior and damage sequence; and more specifically, (b) the BEs influence on the wall load-displacement response; as well as, (c) the applicability of using of the current response limits originally assigned for conventional RM walls to assess RM walls with BEs. Addressing these knowledge gaps is the main motivation behind this dissertation.
       In this respect, this dissertation reports an experimental program, that focuses on bridging the knowledge gap pertaining to the out-of-plane performance of seismically-detailed RM shear walls with BEs, which were not designed to withstand blast loads.
        Meanwhile, from the analytical perspective, plastic analyses were carried out taking into account the different mechanisms that the wall may undergo until peak resistance is achieved. This approach was adopted in order to quantify the resistance function of such walls and determine the contribution of the BEs and web to the overall wall resistance. In addition, the experimental results of the tested walls were used to validate a numerical finite element model developed to compare the resistance function of RM walls with and without BEs. Afterwards, the model was further refined to capture the walls’ performance under blast loads. The pressure impulse diagrams were generated to assess the capability of the current response limits in quantifying the different damage states for walls with different design parameters.
        Furthermore, new response limits were proposed to account for the out-of-plane ductility capacities of different wall components. Finally, a comparison between conventional rectangular walls and their counterparts with BEs using the proposed limits was conducted in the form of pressure-impulse diagram to highlight the major differences between both wall configurations.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Study of Phase Transition in Mg2P2O7 by Measurement of Specific Heat

title: a-B Phase Transition in Mg2P2O7

contributor:
Stager, C. V.
Physics

subject:
phase transition
Mg2P2O7
heat

abstract: This thesis is missing page vi and is not in any of the copies. -Digitization Centre

abstract:
The specific heat of (Mg1-xMnx) 2P2O7 was measured in the vicinity of the alpha-beta phase transition for 0 < x < 0.04. The temperature and character of the phase
transition were found to depend on the composition of the sample and the method of preparation. The results are discussed with relation to the crystal structures of Mg2P2O7 and Mn2P2O7 .

abstract: Thesis

abstract: Master of Science (MS)


title: Restricted Hartree-Fock Calculations in Light Nuclei

title: Hartree-Fock Calculations

contributor:
Volkov, A. B.
Physics

subject:
hartree-fock calculations
light nuclei
restricted hartree-fock calculations

abstract: This thesis is missing pages 152 and 194, neither of which are in the other copies of this thesis. -Digitization Centre

abstract: Restricted Hartree-Fock calculations for light even-even nuclei have been carried out using simple effective interactions. The primary emphasis is on the nature of the intrinsic states, and, in particular, on the deformation of these states. In order to find the equilibrium deformations a representation of deformed cylindrically symmetric states is used. A self-consistent technique for finding the equilibrium size and shape is proposed. There is a strong secondary emphasis on the role of the effective interaction, and four rather different interactions are used. Two of these incorporate a dependence on the density on the nuclear system, and this density dependence improves the systematic behaviour of the energies and sizes of light nuclei.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: On the Design and Construction of a Mass Spectrometer

subject:
mass spectrometer
construction
design

abstract:
Thesis
Master of Science (MS)


title: The Relationship Between Neuronal Discharge and Slow Potentials in the Cat Cerebral Cortex

title: Neuronal Discharge and Slow Potentials

contributor:
Smith, G. K.
Psychology

subject:
neuronal discharge
slow potentials
cat cerebral cortex

abstract: This thesis is missing page 18, the other copies of the thesis are missing it as well. - Digitization Centre

abstract: The work reported in this thesis concerns a possible quantitative relationship between two bioelectric phenomena of the cat cerebral cortex: neuronal discharge and slow potentials. A review of literature dealing with research related to the present topic is given. This is followed by descriptions of the experimental procedure employed and the results obtained. A subsequent discussion in terms of current neurophysiological concepts relates present findings with those of other known research. The accompanying bibliography represents a fairly complete coverage of contemporary and recent experimental and theoretical work related to the present topic.

abstract: Thesis

abstract: Master of Arts (MA)


title: Coaxial Germanium Lithium-Drifted Gamma Radiation Detectors

title: Germanium Lithium-Drifted Detectors

subject:
germanium
lithium
gamma radiation detector
gamma radiation

abstract: This thesis is missing page 36, all other versions of the thesis are missing this page as well. -Digitization Centre

abstract: This thesis deals with the theory, fabrication and application of semi-conductor detectors to gamma ray spectroscopy. The theory section discusses the semi-conductor lattice with respect to the incoming gamma ray and the subsequent hole-electron pairs formed in the diode depletion region. The fabrication section describes the materials and apparatus used in this work to produce the Ge(Li) detectors. A table is given showing the characteristics of these devices as they proceed through the process. The section on the characteristics of these detectors gives information as to how a good detector should operate under certain tests., The detectors made in this laboratory were used to investigate a well known "fission product" nuclide and a neutron capture reaction on a rare earth element. However, these investigations were not exhaustive but only show how the improved resolution of the Ge(Li) detectors has opened up new areas of gamma ray studies.

abstract: Thesis

abstract: Master of Science (MS)


title: Thermal Debinding of Metal Injection Molded Parts with an Agar-Gel Binder System

contributor:
Hrymak, Andrew
Chemical Engineering

subject:
thermal debinding
metal injection

abstract: This thesis is missing page 48, all other copies of this thesis are missing the page as well. -Digitization Centre

abstract:
Metal injection molding (MIM) employs the advantages of injection molding and powder metallurgy and provides a high productivity means to form intricate, low-cost, high performance metal parts. One of the most unique characteristics of MIM is the binder system and the consequent debinding step, which is considered to be major process improvement barrier in the MIM process. A MIM part with a thick section
suffers from a long debinding cycle and it is difficult to avoid defects. Therefore, it is always of interest to find out a method to quickly debind a thick part without defects. PowderFlo® feedstock combines metal powder with an aqueous agar-gel binder system and requires simple air-drying followed by thermal debinding. However, previous studies on this agar-gel binder feedstock mainly focus on sintering, while the debinding step has lacked sufficient attention. A debinding study on agar-gel binder system is conducted in the present project. The metal compacts are formed via compression molding and injection molding, followed
with thermal debinding in order to understand the effects of process parameters on debinding with respect to thickness to determine a good debinding schedule. The thickness transition between thick and thin section is particularly important in the debinding to find a protocol to make parts with both thick and thin sections.
Thermal debinding experiments show that the initial heating rate is the most significant factor due to it may cause visible defect directly and an increase of initial and secondary heating rates may retard binder removal. The air-drying time has less influence on binder extraction for thicker section. Extending the holding time for water and polymer removal is beneficial to obtain better dimensional control. The overall
debinding process parameters have larger effects on thicker parts. For the thickness transition, it is suggested to avoid the combination of too thin and too thick section, increase the joint area, and provide uniform packing during molding.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Development of Electrohydrodynamic (EHD) Liquid Micropumps for Electronics Cooling Applications

contributor:
Ching, C. Y.
Selvaganapathy, P.
Mechanical Engineering

subject:
electrohydrodynamic
liquid micropumps
cooling application

abstract: This thesis is missing page i, all other copies are missing this page as well. - Digitization Centre

abstract: Emergence of efficient cooling techniques has been a crucial factor in development of faster and more powerful electronic equipment and ICs. One of the key obstacles towards further miniaturization is efficient heat removal from regions of high temperature to maintain continued operation of these devices below their maximum operating range. Recently, a significant amount of research has been directed to develop liquid based cooling techniques. For example, microchannel heatsinks have been designed to remove up to 1 kW/cm2. Developing microscale actuators that provide sufficient pressure head is essential for integrating these microscale cooling schemes with the electronic devices. Different techniques can be used to pump fluid in the microscale such as electroosmotic, magnetohydrodynamic, and electrohydrodynamic (EHD) pumping. Among these technologies, EHD pumps are particularly promising for microfluidic devices because they use no moving parts, and uses very small power and has low cost and maintenance requirements. This work presents the development and test of EHD micropumps with different electrode configurations. Four different electrode configurations: (1) planar symmetric electrodes, (2) planar asymmetric electrodes, (3) 3-D symmetric electrodes, and (4) 3-D asymmetric electrodes were investigated. In addition, the effect of different design specifications, such as the inter-electrode spacing and spanwise spacing of the micropillars were investigated. The electrodes were fabricated using a two mask process. First, a thin layer of chromium was deposited on glass as a seed layer for gold electrodes. Positive photoresist (AZ P4620) was patterned to form the mould for the micropillar electrodes. Nickel was electroplated to fill the mold. Subsequently, a Cr/Au layer was patterned to devise the electrode base connector and pads. The microfluidic channels were fabricated by casting polydimethylsiloxane (PDMS) on top of an SU-8 100 (MicroChem Corp.) mould which was patterned to delineate the microchannel structure. The PDMS microchannel was integrated on the electrode base by plasma oxidizing the PDMS and glass wafer, and sealing the connection with liquid PDMS. The pump performance was experimentally determined with Methoxynonafluorobutane (HFE-7100) as the working fluid. All of the micropumps were tested under a no net flow condition to find the maximum pressure generation. The micropumps with planar and asymmetric planar electrode configurations were also tested for maximum flow rate under no imposed back pressure. The results show that the micropumps with the 3D asymmetric electrode design generated a higher pressure head compared to the other micropumps with identical inter electrode spacing under no flow conditions. The micropumps with planar asymmetric design had a higher performance compared to the micropumps with planar asymmetric electric under both no flow condition and no back pressure condition. A maximum pressure head of 2240 Pa was generated at an applied voltage of 900 V by the micropump with 3D asymmetric electrode design. A maximum flow rate of 0.127 mL/min was achieved by the micropump with planar asymmetric electrode configurations. This is five times higher than the maximum flow rate generated by the micropump with the planar symmetric electrode design.

abstract: Thesis

abstract: Master of Science (MS)