title: Log Data Analysis for Software Diagnosis: The Machine Learning Theories and Applications

title: Machine Learning for Log Data Analysis

contributor:
Habibi, Saeid
Mechanical Engineering

subject:
Machine learning
Artificial neural networks
Data mining
Feature extraction
Pattern recognition

abstract:
This research investigates software failure and fault analysis through data-driven machine learning approaches. Faults can happen in any software system and may hugely impact system reliability and user experience. Log data, the machine-generated data that records the system status, is often the primary source of information to track down a fault. This study aims to develop automated systems that recognize recurring faults by analyzing the system log data. The methodology developed in this research applies to the Ford SYNC vehicle infotainment system as well as other systems that produce similar log data.
Log data has been used in manual examination to help trace and localize a fault. This manual process can be effective and sometimes the only feasible way of troubleshooting software faults. However, as the amount of log data increases significantly with the growing complexity and scale of software, the manual workload can get overwhelming. During the system-level validation tests, all system components are producing log data, resulting in tens of thousands of lines of log messages in just a few minutes. Therefore, automated diagnosis has been a promising approach for log data analysis.
Three machine learning approaches are investigated in this research to tackle the fault diagnosis problem: 1) the data mining approach; 2) the statistical feature approach; and, 3) the deep learning approach. The first method attempts to mimic human experts to examine log data. Log sequences representing a fault are extracted through data mining techniques and used to identify anomalies. The method is effective when applied to a small volume of data, but computational efficiency can be an issue when scaling to larger datasets. As its name suggests, the second method involves an examination of the log data’s statistical and numerical features and adapting a machine learning model for decision making. The use of numerical features to describe log data has significant computational efficiency improvement over working directly with sequences. The last approach adopts deep learning models that process the log data in sequential format, enabling more sophisticated feature extraction that often exceeds human capability.  In this research, all three methods are implemented and evaluated in a controlled testing environment, and their strengths and weaknesses are comparatively evaluated.
This study also reports on a novel finding that the time information in a log sequence plays an important role in distinguishing a faulty condition from a normal one. For most software systems, the log sequences are unevenly spaced, meaning that the timestamps associated with log data are nonuniform. Existing log analysis studies generally overlooked the time information while emphasizing log sequences. This research proposes a novel deep learning structure to unify the processing of timestamps and log sequences. The timestamps are integrated through interpolation at an intermediate layer of a neural network. Testing results demonstrate that the inclusion of timestamps makes a significant contribution to identifying a fault, and that models using time stamps can push the performance to a higher level.

abstract: Dissertation

abstract: Doctor of Engineering (DEng)


title: INFRASTRUCTURE ASSET MANAGEMENT ANALYTICS STRATEGIES FOR SYSTEMIC RISK MITIGATION AND RESILIENCE ENHANCEMENT

contributor:
El-Dakhakhni, Wael
Wiebe, Lydell
Civil Engineering

subject:
descriptive analytics
infrastructure asset management
predictive analytics
prescriptive analytics
systemic risk

abstract: The effective implementation of infrastructure asset management systems within organizations that own, operate, and manage infrastructure assets is critical to address the main challenges facing the infrastructure industry (e.g., infrastructure ageing and deterioration, maintenance backlogs, strict regulatory operating conditions, limited financial resources, and losing valuable experience through retirements). Infrastructure asset management systems contain connectivity between major operational components and such connectivity can lead to systemic risks (i.e., dependence-induced failures). This thesis analyzes the asset management system as a network of connected components (i.e., nodes and links) to identify critical components exposed to systemic risks induced by information asymmetry and information overload. This thesis applies descriptive and prescriptive analytics strategies to address information asymmetry and information overload and predictive analytics is employed to enhance the resilience. Specifically, descriptive analytics was employed to visualize the key performance indicators of infrastructure assets ensuring that all asset management stakeholders make decisions using consistent information sources and that they are not overwhelmed by having access to the entire database. Predictive analytics is employed to classify the resilience key performance indicator pertaining to the forced outage rapidity of power infrastructure components enabling power infrastructure owners to estimate the rapidity of an outage soon after its occurrence, and thus allocating the appropriate resources to return the infrastructure to operation. Using predictive analytics allows decision-makers to use consistent and clear information to inform their decision to respond to forced outage occurrences. Finally, prescriptive analytics is applied to optimize the asset management system network by increasing the connectivity of the network and in turn decreasing the exposure of the asset management system to systemic risk from information asymmetry and information overload. By analyzing an asset management system as a network and applying descriptive-, predictive-, and prescriptive analytics strategies, this dissertation illustrates how systemic risk exposure, due to information asymmetry and information overload could be mitigated and how power infrastructure resilience could be enhanced in response to forced outage occurrences.

abstract: Thesis

abstract: Doctor of Science  (PhD)

abstract: Effective infrastructure asset management systems are critical for organizations that own, manage, and operate infrastructure assets. Infrastructure asset management systems contain main components (e.g., engineering, project management, resourcing strategy) that are dependent on information and data. Inherent within this system is the potential for failures to cascade throughout the entire system instigated by such dependence. Within asset management, such cascading failures, known as systemic risks, are typically caused by stakeholders not using the same information for decision making or being overwhelmed by too much information. This thesis employs analytics strategies including: i) descriptive analytics to present only relevant and meaningful information necessary for respective stakeholders, ii) predictive analytics to forecast the resilience key performance indicator, rapidity, enabling all stakeholders to make future decisions using consistent projections, and iii) prescriptive analytics to optimize the asset management system by introducing additional information connections between main components. Such analytics strategies are shown to mitigate the systemic risks within the asset management system and enhance the resilience of infrastructure in response to an unplanned disruption.


title: A Reluctance Mesh-Based Modeling Method for Electromagnetic Characterization and Radial Force Calculation in Switched Reluctance Machines

contributor:
Emadi, Ali
Bilgin, Berker
Electrical and Computer Engineering

subject:
Switched reluctance machines
Electromagnetic model
Magnetic equivalent circuit
SRM
MEC

abstract:
Switched Reluctance Machines (SRMs) are gaining more attention due to their simple and rugged construction, low manufacturing cost, and high-speed operation capability. An electromagnetic model of the machine is needed in the design and analysis processes. The required accuracy level of the model depends mainly on the application.

Designing an SRM is an iterative process. Usually, finite element method (FEM) is employed in all design stages, which might require extensive computation burden. The magnetic equivalent circuit (MEC) method is an alternative for typical FEM. MEC models require less computational resources and they can help determine the electromagnetic performance with a reasonable accuracy. The conventional MEC method can be challenging when modifying the motor geometry while conducting dynamic analysis with current control. This thesis proposes a reluctance mesh-based MEC model for SRMs that can overcome those challenges. Reluctance mesh-based MEC models are developed for 3-phase 6/4, 6/16, 12/8 SRMs and 4-phase 8/6, 8/10, and 16/12 SRMs. The implemented MEC-based modeling method is validated using FEM and experimental results.

Acoustic noise and vibration is one of the shortcomings of an SRM. The radial force density in the airgap should be calculated before analyzing and mitigating acoustic noise and vibration. This thesis proposes a radial force density calculation method for SRMs using the proposed MEC model. Fourier series is used to calculate the harmonics of the radial force density. The results obtained from the MEC model are verified using FEM models.

SRM is a promising candidate for electric propulsion systems. In the design process of an SRM, the motor geometry needs to be determined. This thesis applies the proposed MEC technique to the design process of a 3-phase 12/16 SRM for a high lift motor in the NASA Maxwell X-57 electric aircraft. The design is verified using the results computed from FEM.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Electric motors are utilized in our daily life in various applications such as washing machines, refrigerators, air conditioners, fans, vacuum cleaners, blenders, and many other devices and tools. Motors are widely used in residential, industrial, commercial, and transportation applications. Due to the environmental impact of burning fossil fuels, transportation systems are moving into electrified propulsion. Electric motors with lower cost and higher efficiency are on the path to replacing the traditional combustion engines in vehicles. Among the different electric motors available, switched reluctance motor (SRM) is becoming a promising candidate in future electrified transportation systems due to their simple construction. Developing a motor is a time-consuming and costly task. Therefore, it is essential to determine the characteristics of an SRM before manufacturing it. A mathematical framework is proposed in this thesis to address this problem. The proposed framework is capable of determining the characteristics of an SRM accurately.


title: MONITORING AND CONTROL FOR LASER POWDER BED FUSION ADDITIVE MANUFACTURING

contributor:
Mohamed Elbestawi
Mechanical Engineering

subject:
Additive Manufacturing
Control System
Monitoring

abstract:
Laser powder bed fusion (L-PBF) refers to an additive manufacturing (AM) process in which a high-intensity laser source melts powders in a layer-by-layer manner to fabricate parts based on a computer-aided design (CAD) model without almost any geometrical limitations. The development of the L-PBF process has provided an outstanding opportunity to manufacture unique parts which are practically impossible to be produced by conventional manufacturing methods. The L-PBF process also does not require intricate build tools and assembly processes. However, quality issues such as non-uniform microstructure or mechanical properties, porosities, and surface roughness deteriorate the quality of the parts fabricated by the L-PBF process. Therefore, the reliability and the repeatability of the process are required to be addressed.
This study deals with improving the quality of the part fabricated by the L-PBF process and making the process more reliable and repeatable. The control approach was employed to elevate the quality of the final part from three different aspects. First, making the microstructure and microhardness of the part uniform through a control approach was investigated. Three controllers, namely, proportional (P), adaptive P, and quasi sliding mode, were developed to control the melt pool temperature for the Inconel 625 superalloy. An analytical-experimental model was presented to evaluate the performance of controllers via simulation. A monitoring system consisting of a two-color pyrometer was utilized off-axially to monitor the melt pool temperature for use by the controllers as a feedback signal. The results indicated that the control approach led to microhardness and microstructure uniformity, resulting from the reduced variation in the primary dendrite arm spacing compared to the case with constant process parameters. Second, the control approach was utilized to produce optimum parts instead of using the energy density criterion. Temperature domains corresponding to the most common porosities, namely, lack of fusion (LOF), lack of penetration (LOP), and keyhole, were determined in a range of process parameters using a thermal imaging system. A safe zone was introduced by defining a lower and an upper limit based on the critical temperatures causing transitions from LOP to defect-free and from defect-free to keyhole zones, respectively. A proportional-integral-derivative (PID) controller was used to maintain the melt pool temperature within the safe zone during the L-PBF process for Inconel 625 and avoid the formation of porosities, regardless of the initial condition selected and the scanning speed employed. In all cases, a short settling time in the order of the printing time for a few layers was required to reach the steady-state condition at which defect-free parts could be obtained. Finally, minimizing the top surface roughness of the parts manufactured by the L-PBF process by deploying a Feedforward plus Feedback control system was targeted in this study. The most common factors affecting the surface quality, namely, balling, lack of inter-track overlap, overlapping curvature of laser scan tracks, and spatters, were investigated through a monitoring system consisting of a high-speed camera, a zooming lens, and a short pass filter. The desired melt pool width and the critical value for the level of spatters were determined using the imaging system and subsequent image processing. An experimental model was developed, and the control system was designed accordingly. Both simulations and experimental results showed excellent transient performance of the control system to reach the desired melt pool width only after printing a few layers. Also, the control system was evaluated at different scanning speeds and with different geometries. The results obtained from this study indicated that controlling the geometry of the melt pool can mitigate significant defects occurring during the process and minimize the top surface roughness.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Responsibility and Justice: Considerations for Increasing Access to Prenatal Care. An Interpretive Descriptive Study of Health and Service Providers Understandings of Inadequate Prenatal Care in Hamilton.

contributor:
Darling, Liz
Health Research Methodology

subject:
inadequate prenatal care
marginalized
health service accessibility
newborn apprehension
community centred care
social determinants of health
qualitative methods
critical theory

abstract: Prenatal care (PNC) is an essential health service that can reduce adverse health and social outcomes through prevention, detection and treatment of abnormalities of pregnancy. It offers an opportunity to mitigate the impact of the Social Determinants of Health (SDoH) on individual patients through advocacy and referral to social services. Despite a publicly funded health care system in Canada, disparities in access to PNC persist. Much is known about the barriers to PNC and client experiences of inadequate PNC (IPNC). Very little is known about care provider perspectives of IPNC, what should be done about it and are the barriers to doing it. The goal of this project was to address this gap in knowledge to inform the development of novel care delivery models that could reduce disparities in access to PNC in Hamilton. Using a Critical Theory lens, I conducted an interpretive descriptive study using individual interviews and focus groups with health and social service providers in Hamilton to explore their understandings of IPNC. Participants viewed IPNC as a small but important phenomenon disproportionately impacting people who are marginalized. The experience of IPNC is chaotic, worrisome and joyful for providers. An interdisciplinary, midwifery-led outreach PNC model would better meet the needs of the client population and providers alike.  A Community Centred Care model of PNC embodies and enhances participant suggestions for addressing IPNC. Access to abortion, postpartum care and newborn apprehension require special attention. Peer participation and the impacts of patriarchy and racism must be addressed in the development of future PNC models. The ways in which participants described and proposed intervening in IPNC revealed an individualized understanding of the SDoH that is paralleled in existing research on IPNC.  This conceptualization of the problem obscures the root causes of disparities in access and warrants future consideration.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Prenatal care (PNC) can help to reduce complications of pregnancy and birth and connect expecting families with other support services.  Even though health care is free in Canada, people who are marginalized struggle to access enough PNC.  We know the complexities of people’s lives and their negative experiences with the health care system prevent them from getting PNC.  We know little about what PNC for people who don’t access it is like for the providers or why they can’t make their care easier to access. Mindful of systems of power, the goal of this research is to explore how health and social service providers understand inadequate PNC (IPNC), to inform accessible PNC models. Participants proposed an interdisciplinary outreach PNC model responsive to needs of the community.  The Social Determinants of Health were an important part of how participants understood IPNC which shaped the way that they proposed to address it.


title: Self-Reported Health among Community-Dwelling Older Adults: A Multimethod Study to Understand the Complexity and Role of Adaptation to Health Adversity

contributor:
Markle-Reid, Maureen
Nursing

subject:
older adults
multimorbidity
self-reported health
nursing
cross-sectional analysis
qualitative case study
multimethod
resilience

abstract: Self-reported health is typically captured as a response to the question, “In general, would you rate your health as excellent, very good, good, fair or poor?” Among community-dwelling older adults (≥65 years), self-reported health decreases as the number of chronic conditions increases. Despite this well-documented relationship, little is known about how other sociodemographic or health-related factors may shape this relationship, what may predict high self-reported health among this population, or how older adults perceive these factors as influencing their perceptions of health. Informed by the Lifecourse Model of Multimorbidity Resilience, the objective of this multimethod research study was to advance understanding of self-reported health among community-dwelling older adults. To this end, four research studies were completed: 1) scoping review of the factors associated with self-reported health, 2) cross-sectional analysis of baseline data from the Canadian Longitudinal Study on Aging to understand the relationship between multimorbidity and self-reported health and the factors that predict high self-reported health; 3) qualitative case study to explore the influence of individual, social, and environmental factors on self-reported health, including multimorbidity resilience, in community-dwelling older adults, and; 4) a multimethod study that brought together all findings in a matrix analysis. From this work, two meta-inferences were generated: 1) the factors that shape self-reported health are multidimensional and complex; and 2) adaptation to health adversity, resulting from experiences acquired over the lifecourse, shape how older adults perceive their health. Findings from this work advance three implications. First, there is a need to use and apply information gained by asking about self-reported health in clinical practice to inform care planning. Second, there is a need for whole person care to guide health and social care policy for older adults. Third, future health research must further explore longitudinal understanding of self-reported health as well as additional qualitative understanding of the differences of those older adults with the well-being paradox.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Cloud-scale molecular gas properties in nearby merging galaxies

contributor:
Wilson, Christine D.
Physics and Astronomy

subject:
ISM: clouds
ISM: kinematics and dynamics
ISM: jets and outflows
ISM: structure
galaxies: ISM
galaxies: interactions
galaxies: jets
galaxies: starburst
galaxies: star formation
galaxies: nuclei
submillimetre: ISM

abstract: In this thesis we present cloud-scale ALMA observations of two local mergers, NGC 3256 and NGC 4038/9 (the "Antennae"), in CO J=2-1. Through a pixel-based analysis of NGC 3256 we measure molecular-gas properties and compare to nearby spiral galaxies from the PHANGS-ALMA survey. NGC 3256 exhibits high mass surface densities, velocity dispersions, peak brightness temperatures, virial parameters, and internal turbulent pressures. High surface densities are expected to accompany its high star-formation rate, and high brightness temperatures may indicate warmer gas, heated by the vigorous star formation. Large virial parameters and internal pressures imply the molecular gas is not bound by self-gravity, but we explore how material external to clouds could alter this. We argue the molecular gas in NGC 3256 is smoother than in nearby spiral galaxies down to 55 pc. We also perform a cloud analysis of our NGC 3256 observations, identifying 185 clouds, and find similar results to the pixel analysis. We calculate additional cloud properties including eccentricity, CO luminosity, CO-estimated mass, virial mass, size-linewidth coefficient, and free-fall time. Properties in NGC 3256 are extreme compared to clouds from PHANGS-ALMA, including slightly larger clouds and shorter free-fall times. Cloud eccentricities in NGC 3256 are similar to those in PHANGS-ALMA galaxies, possibly indicating similar average cloud dynamical states. The shape of the cloud mass function in NGC 3256 is similar to many PHANGS-ALMA galaxies. Finally, we analyse our NGC 4038/9 observations using the same pixel methods as used in NGC 3256. NGC 4038/9 also harbours extreme molecular-gas properties and potentially smoother emission compared to spiral galaxies, but not as extreme as NGC 3256. We find the most-massive spiral galaxies have central molecular-gas properties similar to the mergers. Virial parameters in NGC 4038/9 are similar to many spiral galaxies, making it quite different from NGC 3256, potentially due to their different merger stages. Comparison of the overlap region of NGC 4038/9 in CO (2-1) to CO (3-2) shows general agreement.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Disease and Empire: Women and Caregiving in Colonial Jamaica, 1850-1920

contributor:
Juanita, De Barros
History

subject:
Medical History
Nursing History
19th century epidemics
Folk healers

abstract:
This research about women’s caregiving experiences in Jamaica uses the conceptual frameworks of intersectionality and anti-racist feminist perspectives to interpret and analyze the experiences of informal and formally trained nurses and folk healers in post-slavery Jamaica. This study explores how race, colour, class, gender, citizenship, and national identity intersected to define and shape women’s experiences as caregivers in Jamaica between the 1850s and the 1910s. By integrating scholarly interpretations about a plural health system with case studies about the management of diseases and developments in nursing, this research presents an inclusive analysis of female caregivers (British, Euro-American, and Afro-Jamaican nurses and folk healers) in post-slavery Jamaica.
The late nineteenth to the early twentieth centuries was the period of the “new” imperialism characterized by the growth of caregiving and medical philanthropy in aiding the expansion of imperial pursuits and the civilizing mission of empires (British and US). Caregiving reveals how gender, race, class, and national identity intersected to shape the management of diseases in post-slavery Jamaica. On the one hand, formal caregiving was a tool for empire-building through colonial medical policies that aimed to heal the bodies and “civilize” the mentality of colonized peoples. On the other hand, informal caregiving empowered oppressed people to reshape cultural customs by adapting healing and religious practices to challenge British imperialism and claim citizenship.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: This study examines the management of epidemics and disease in post-slavery Jamaica by highlighting the contributions of female caregivers, such as informally and formally trained nurses and Afro-Jamaican folk healers. It argues that caregiving provided by the government medical system and Afro-Jamaican folk healing developed from the mid-nineteenth to the early twentieth century in response to the challenges of adjusting to emancipation, frequent epidemics and encounters with disease. However, the government’s efforts to contain epidemics and disease were inadequate because of a shortage of medical practitioners, insufficient medical infrastructure, and white medical elites’ racial and class prejudices toward the labouring class. Nursing developed in parallel with establishing public hospitals and medical institutions in the urban centre as sites to control the labouring-class to mitigate epidemics and disease in post-slavery Jamaica. British, Euro-American, and Afro-Jamaican female caregivers deployed religious and medical services (caregiving) that reinforced and challenged racial, class and gender hierarchies during the post-slavery period in Jamaica.


title: Unraveling the mechanism of ADAMTS13 resistance to protease inhibition

contributor: Medical Sciences (Blood and Cardiovascular)

subject: ADAMTS13

subject: VWF

subject: A2M

subject: TIMP3

subject: Marimastat

abstract:
Background: ADAMTS13 is a metalloprotease that regulates the delicate balance between VWF multimeric length and its platelet capturing capacity. Unlike other ADAMTS and coagulation proteases, ADAMTS13 exhibits a prolonged half-life of several days as an active protease, suggesting that it is protected from inhibitors of metalloproteases in blood. Here, we investigate the mechanism by which ADAMTS13 is resistant to protease inhibition.

Methods: C-terminal domain truncations of ADAMTS13 (MDTCS and MD) and chimeras with ADAMTS5 (MD13/TCS5, M13/DTCS5, MD5/TCS13, and MD5(TCS-CUB13)) were generated. Metalloprotease domain segments from ADAMTS5 were swapped into MDTCS13 corresponding to the gatekeeper triad (R193, D217, and D252) (MDTCS-G), the variable loop (G236-S263) (MDTCS-V5), and the calcium-binding loop (R180-R193) (MDTCS-C5). MDTCS-GVC5 was generated to study these features simultaneously. Alpha 2-macrogloublin (A2M), tissue inhibitors of metalloproteinases (TIMPs), and small molecule inhibitor (Marimastat) were used as inhibitors, and tested using FRETS-VWF73 and Western blot.

Results: MDTCS, MD, MD13/TCS5, M13/DTCS5, MDTCS-G, MDTCS-V5, and MDTCS-C5 constructs were resistant to all inhibitors, whereas MD5/TCS13 was inhibited. The presence of the closed conformation attenuated MD5(TCS-CUB13) proteolysis by 50-fold, while displaying a slower rate of inhibition compared to MD5/TCS13. We report the kinetic parameters of the unique features of the metalloprotease domain (the gatekeeper triad, the variable loop, and the calcium-binding loop). Moreover, simultaneously swapping these features sensitized MDTCS-GVC5 to Marimastat.

Conclusion: Our findings reveal that the closed conformation confers global latency, while the metalloprotease domain confers local latency of ADAMTS13. The local latency is maintained by the flexibility of the variable loop and the calcium-binding loop, which fold across the active site cleft to restrict inhibitor and substrate access. Extensive engagement of exosites by VWF can readily displace these loops, thereby activating ADAMTS13 from its latent form. Altogether, we present novel insight into the mechanism by which ADAMTS13 is resistant to protease inhibition.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Hemostasis is the body’s natural process to prevent bleeding and maintain blood flow. The ability of a blood protein, called VWF, to stop bleeding upon injury is regulated by the protein ADAMTS13. ADAMTS13 circulates in the blood for days, but its function cannot be stopped by inhibitors. Here, we investigate the mechanism by which ADAMTS13 is resistant to inhibition. We found that several structures of ADAMTS13, called domains and loops, protect it from inhibitors. Folding of the distal domains to the centre of ADAMTS13 partially protected ADAMTS13 from inhibitors. Further investigation revealed that two flexible loops close to the active site of ADAMTS13 were primarily responsible for protecting ADAMTS13 from inhibitors. We suggest that the flexibility of these loops guard against inhibition by folding across the active site. These results are important because advances have been made to use ADAMTS13 therapeutically in many clotting illnesses, such as strokes.


title: Using Amines and Aldehydes as a Novel Crosslinking Method for Silicone Materials

contributor:
Brook, Michael
Chemistry and Chemical Biology

subject: Silicone Materials

abstract:
This thesis explores the use of amine-functionalized silicone oils with various aliphatic and aromatic aldehydes as a novel method of crosslinking functional silicone materials via imines and the application of the resulting materials. These reactions overcome many of the drawbacks of traditional methods for crosslinking silicones and produces materials with novel properties that can enable their use in different applications. Furthermore, the differences in reactivity between the two types of aldehydes lead to two unique crosslinking motifs. Aromatic aldehydes produce conjugated Schiff-base crosslinks, while the crosslinking with aliphatic aldehydes undergoes various condensation reactions to give novel silicone materials.
The use of small aliphatic aldehydes such as formaldehyde, glutaraldehyde, and glyoxal was found to rapidly crosslink aminopropylsilicones into elastomeric materials. The high reactivity of the aldehyde towards the amine-moieties also allows for robust crosslinking into elastomers that can occur even in the presence of water, a remarkable feature for silicones that are normally water insoluble. These properties allowed for the application of the material as an ink for 3-D printing, where the rapid crosslinking allowed for the study of a novel free-space droplet merging printing method.
Silicone materials crosslinked with aromatic aldehydes produce conjugated Schiff-base bonds. These crosslinks can undergo dynamic exchange reactions in the presence of an amine catalyst to alter bonding in the material. These reactions gave the silicone chemoplastic and thermoplastic properties, allowing the material to be remoulded and reprocessed. Naturally-derived aromatic aldehydes can also be used as the crosslinker, allowing for a multi-faceted approach to increasing the sustainability of silicone materials by increasing their utility, making them reprocessable, thus extending their lifespan while using sustainable materials as a filler.

abstract: Thesis

abstract: Doctor of Science  (PhD)


title: Laser Powder Bed Fusion of Nickel-based Superalloys

contributor:
Elbestawi, Mohamed
Mechanical Engineering

subject:
Laser powder bed fusion
Inconel 625
Inconel 718
Residual stress
Fatigue
Additive manufacturing
Finite element modeling
Shot peening

abstract:
This thesis aims to investigate the manufacturability of nickel-based superalloys, IN625 and IN718, using the laser powder bed fusion (LPBF) process. The study provides a better understanding of the process-structure-property of nickel-based superalloys, their fatigue life, and subsequent post-processing.
First, the process-structure-property was investigated by selecting a wide range of process parameters to print coupons for IN625 and IN718. Next, a subset of process parameters was defined that would produce high relative density (>99%), low surface roughness (~2 μm), and a low tensile RS.
Second, a multi-scale finite element model was constructed to predict the temperature gradients, cooling rates, and their effect on RS. At constant energy density, RS is affected by scan speed, laser power, and hatch spacing, respectively.
Third, the optimum set of parameters was used to manufacture and test as-built and shot-peened samples to investigate the fatigue life without costly heat treatment processes. It was found that shot peening resulted in a fatigue life comparable to wrought heat-treated unnotched specimen. Additionally, IN625 had a better fatigue life compared to IN718 due to higher dislocations density as well as the absence of γ´ and γ´´ in IN718 due to the rapid cooling in LPBF.
Finally, the effect of post-processing on dimensional accuracy and surface integrity was investigated. A new approach using low-frequency vibration-assisted drilling (VAD) proved feasible by enhancing the as-built hole accuracy while inducing compressive in-depth RS compared to laser peening, which only affects the RS. These favorable findings contributed to the scientific knowledge of LPBF of nickel-based superalloys by determining the process parameters optimum window and reducing the post-processes to obtain a high fatigue life, a better dimensional accuracy, and improved surface integrity.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Applications of Mendelian randomization to the discovery and validation of blood biomarkers in cardiometabolic disease

contributor:
Paré, Guillaume
Medical Sciences

subject:
Mendelian randomization
genome-wide association study
biomarker
testosterone
lipoprotein(a)
atrial fibrillation
trefoil factor 3
chronic kidney disease
UK Biobank
cardiometabolic disease

abstract: Peripheral blood biomarkers can inform clinical care and drug development. Establishing causality between biomarker and disease is often critical for such applications, but epidemiological studies are limited due to biases from confounding and reverse causation. Mendelian randomization analysis leverages random inheritance of genetic variants at conception to mimic properties of randomized studies and estimate unconfounded effects between biomarker and disease, or vice-versa. This thesis demonstrates the utility of Mendelian randomization as a complementary tool to elucidate observational studies, predict drug safety and repurposing opportunities, and improve diagnostic biomarkers for cardiometabolic diseases. First, we characterized the hypothesized relationship between lipoprotein(a) and atrial fibrillation. We demonstrated both observed and genetically predicted lipoprotein(a) levels were associated with higher risk of atrial fibrillation across multiple independent cohorts. Importantly, risk was partly mediated independent of atherosclerotic cardiovascular disease, a known consequence of elevated lipoprotein(a) and itself a risk factor for atrial fibrillation. Next, we explored the lifelong effects of endogenous testosterone across a comprehensive set of 461 health outcomes in 161,268 males from the UK Biobank cohort. Using Mendelian randomization analysis, we found higher testosterone had beneficial effects on body composition and bone mineral density but adverse effects on prostate cancer, androgenic alopecia, spinal stenosis, and hypertension. Finally, we applied Mendelian randomization with the intention of discovering biomarkers caused by disease, which are expected to represent markers of early disease. As a proof-of-concept, we applied this framework to identify biomarkers associated with genetic predisposition to kidney function among 238 biomarkers measured in the ORIGIN trial. We discovered reduced kidney function caused increased trefoil factor 3 and showed its addition to models with known risk factors improved discrimination of incident early-stage chronic kidney disease. Taken together, Mendelian randomization identified biomarkers that warrant further study, with promising implications for screening, prevention, and treatment of different cardiometabolic diseases.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Biological markers associated with disease can inform novel therapeutics or diagnostics but distinguishing causation from correlation is challenging. Mendelian randomization – a technique that leverages random inheritance of genetic variation to infer causality – was used to examine the role of biomarkers in cardiometabolic diseases. First, we implicated lipoprotein(a) as a risk factor for atrial fibrillation that acts independent of atherosclerotic cardiovascular disease. Second, we comprehensively characterized the lifelong effects of testosterone on health outcomes in males, where we found evidence of both beneficial and adverse effects on disease. Finally, we discovered trefoil factor 3 as a diagnostic marker for early-stage chronic kidney disease. Altogether, this thesis demonstrated different applications of Mendelian randomization that showcase its utility as a complementary tool to reveal causal biomarkers, and served to identify biomarkers for cardiometabolic diseases that merit further studies to evaluate their potential benefit on patient care.


title: Environmental sources and treatment strategies of organic micropollutants

contributor:
de Lannoy, Charles-François
Chemical Engineering

subject:
peatland restoration
micropollutant removal
membrane separation
adsorption
nanocomposite
bio-based sorbent

abstract:
Organic micropollutants (OMPs) in climate change affected natural environment such as wetlands, and engineered systems have brought serious concerns for water security and public health. These issues have increased the demand for better managing water resources and developing effective technologies for aqueous micropollutants removal. This thesis investigated these subjects through the following five sub-research projects.
First, boreal peatland was used as a case study for understanding how peatland fires and droughts impacts peatland resilience. Laboratory results suggested that heating and moisture condition, coupled with peat organic hydrophobic transformations, influence peat soil hydrophobicity and the resultant water-extractable pollutant leaching, which potentially threatens peatland downstream receiving waters such as potable waters by high organic loads.
Further, post-fire peat chemistry and their mechanistic relationships to leached pollutants (total organic carbon (TOC), nutrients and phenols) were elucidated through a laboratory leaching study. Increased contaminant loading was observed in post-heated peat leachates, suggesting negative effects to water treatment efficiency and an increase of treatment costs to surface waters as potable water source.
Next, peat soils damaged from extreme fires and droughts were upcycled for producing high surface area, value-added porous carbons based on a rapid, facile chemical activation approach. This application had the simultaneous benefit of peatland ecological restoration, protecting downstream communities from heavy run-off, and using the sustainable damaged peats for effective environmental remediation though adsorption.
Moreover, a critical review of nano-enabled composite membranes for OMP removal (size-exclusion, adsorption, charge interaction, and photo- and electro-catalysis) and their respective benefits and limitations were discussed. This work brought new perspectives for next-generation nanocomposite membranes for OMP removal.
Finally, a novel, hyperbranched polyethylenimine (HPEI) crosslinked iron doped reduced graphene oxide (rGO) nanocomposite membrane was synthesized for process-intensified flow-through separation of phenolic micropollutants. Mechanisms and separation performance to phenolic micropollutant and azo dyes were investigated.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Climate change, industrial manufacture, and population growth have been exacerbating the global water stress. Organic micropollutants (OMPs) are potentially toxic, persistent and can exist even at trace levels, which have been increasingly discovered and identified in natural and built systems. In this research, environmental chemistry of climate-change impacted boreal peatland soils, and their mechanistic relationships to peat soil hydrophobicity, organic substance transformations, micropollutant leaching, and impacts to downstream potable water quality was investigated as a case study. Two different innovative water treatment strategies were developed for restoring peatland resilience and enhancing water resource sustainability including treating peatland phenolic micropollutants. The first approach converted shallow layer wildfire- and drought- damaged peats into value-added porous carbons for adsorption. The second approach synthesized a novel reduced graphene oxide (rGO) nanocomposite membrane for process-intensified flow-through separation. These solutions provide novel insights for source water protection and wastewater treatment in adaption to climate change.


title: Big Data, Small Microbes: Genomic analysis of the plague bacterium Yersinia pestis

contributor:
Poinar, Hendrik
Anthropology

subject:
Ancient DNA
Plague
Anthropology
Genomics
Bioinformatics
Denmark
NCBI
SRA

abstract: Pandemics of plague have reemerged multiple times throughout human history with tremendous mortality and extensive geographic spread. The First Pandemic (6th - 8th century) devastated the Mediterranean world, the Second Pandemic (14th - 19th century) swept across much of Afro-Eurasia, and the Third Pandemic (19th - 20th century) reached every continent except for Antarctica, and continues to persist in various endemic foci around the world. Despite centuries of historical research, the epidemiology of these pandemics remains enigmatic. However, recent technological advancements have yielded a novel form of evidence: ancient DNA of the plague bacterium Yersinia pestis. In this thesis, I explore how genomic data can be used to unravel the mysteries of when and where this disease appeared in the past. In particular, I focus on phylogenetic approaches to studying this 'small microbe' with 'big data' (i.e. 100s - 1000s of genomes). I begin by describing novel software I developed that supports the acquisition and curation of large amounts of DNA sequences in public databases. I then use this tool to create an updated global phylogeny of Y. pestis, which includes ~600 genomes with standardized metadata. I devise and validate a new approach for temporal modeling (i.e. molecular clock) that produces robust divergence dates in pandemic lineages of Y. pestis. In addition, I critically examine the questions that genomic evidence can and cannot address in isolation, such as whether the timing and spread of short-term epidemics can be confidently reconstructed. Finally, I apply this theoretical and methodological insight to a case study in which I reconstruct the appearance, persistence, and disappearance of plague in Denmark during the Second Pandemic. The three papers enclosed in this sandwich-thesis contribute to a larger body of work on the anthropology of plague, which seeks to understand how disease exposure and experience change over time and between human populations. Furthermore, this dissertation more broadly impacts both prospective studies of infectious disease, such as environmental surveillance and outbreak monitoring, and retrospective studies, which seek to date the emergence and spread of past pandemics.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: The Plague is a disease that has profoundly impacted human history and is responsible for some of the most fatal pandemics ever recorded. It may surprise many to know that this disease is not a bygone of a past era, but in fact is still present in many regions of the world. Although researchers have been studying plague for hundreds of years, there are many aspects of its epidemiology that are enigmatic. In this thesis, I focus on how DNA from the plague bacterium can be used to estimate where and when this disease appeared in the past. To do so, I reconstruct the evolutionary relationships between modern and ancient strains of plague, using publicly available data and new DNA sequences retrieved from the skeletal remains of plague victims in Denmark. This work offers a new methodological framework for large-scale genetic analysis, provides a critique on what questions DNA evidence can and cannot answer, and expands our knowledge of the global diversity of plague.


title: The Development of Employment Protection Legislation in the United Kingdom (1963-2018) and Sweden (1971-2020)

contributor:
McBride, Stephen
Political Science

subject:
United Kingdom
Sweden
collective laissez-faire
employers’ associations
trade union organizations
collective bargaining
crisis
parliamentary democracy
political parties
policy actors
individual employment law
employment protection legislation
notice of termination
redundancy payments
unfair dismissal protection
job reinstatement
allowance of fixed-term contracts
institutional power resources
labour courts
European Union Commission
enforcement gap
labour market insiders and outsiders
deregulation

abstract: Several interesting findings emerged from this study. First, strong labour movements still failed to successfully bargain for employment protections due to resistance from employers to encroachments on their institutionalized managerial prerogatives. Second, governments favoured a policy of abstentionism and acquiescence to the collective-laissez-faire tradition until the critical juncture of the 1960s and 1970s. Third, the increasing power resources of trade unions and a deteriorating socio-economic climate created a window of opportunity for bold government action to improve industrial relations, albeit without the consent of employers, and at first, unions. Fourth, contrary to the liberalizing pressures one would expect to find in an archetypical free market economy, the UK has implemented far more statutory protections than deregulatory reforms. Fifth, in contrast to its traditional non-intervention in industrial relations and reputation for worker-protective regulations, Swedish governments have enacted numerous statutes, both restricting and freeing managerial prerogatives in the hiring and firing process. Sixth, statutory employment protections became an independent set of institutional power resources for unions in the long run, serving their organizational and representational interests in important ways. Seventh, unions and left parties consistently defended and advanced the policy preferences of their core constituencies in secure employment by privileging the job security of regular contracts. Eighth, employers and parties on the right of the political spectrum consistently opposed restrictions on the managerial capacity to hire and fire at will, especially for small businesses. Nineth, to increase flexibility without threatening the stability of regular contracts, reforms over the years had to foster atypical forms of work, creating a regulatory gap between permanent and temporary employment, particularly in Sweden. Tenth, differences exist between job security in the statute books and job security in action, particularly in the UK where this gap pervades all aspects of the unfair dismissal system. These findings suggest employment protection legislation has developed in ways far more complex, dynamic and contradictory than is commonly assumed by prominent theories of comparative political economy.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: This thesis examines how and why employment protection legislation developed in the United Kingdom and Sweden in the ways that it did from its early beginnings to the present period. It hopes to offer answers to questions about the initial impetus for statutory regulation, the number, content and impact of significant legislative changes and the preferences of key stakeholders with material interests in the policymaking process. It does this by drawing on a variety of both primary and secondary source materials, including employment protection databases, parliamentary records and research publications. At the same time, it assesses the explanatory merit of dominant theories in the political economy literature by testing them against voluminous empirical evidence and provides a multi-factorial account to fill the gaps in the existing body of knowledge.


title: Fetuin-A Adsorption on Tunable Polydimethylsiloxane and Subsequent Macrophage Response

contributor:
Sask, Kyla
Biomedical Engineering

subject:
Protein adsorption
Biomaterials
Cell interactions

abstract:
To date, protein adsorption is an unavoidable response to implanted biomaterials. When proteins interact with materials, adverse biological events such as thrombus formation and inflammation can occur and challenge device efficacy. Protein adsorption is influenced by various material and surface properties which can be modified in efforts to alter the protein-material interactions and the subsequent cellular response. There is a need for simple modifications of commonly used biomaterials and the effect of these modifications on (1) material properties (2) proteins and (3) cells is important to study.
In this work, the effect of modifying polydimethylsiloxane (PDMS) and its interactions with fetuin-A are studied for potential immunomodulatory properties. PDMS modifications are achieved by altering the ratio of PDMS formulations to simply and effectively control elastic modulus, and by coating PDMS with polydopamine (PDA), a molecule commonly used as a bioglue. Surface characterization confirmed that altering the PDMS formulation changed the elastic modulus without affecting surface wetting properties. Minor changes in surface roughness via atomic force microscopy and surface chemistry via x-ray photoelectron spectroscopy were detected on some samples, and the deposition of PDA was confirmed. Protein adsorption studies provided quantitative and qualitative data on fetuin-A interactions. It was determined that fetuin-A adsorption was influenced by the PDMS formulations, and that the preferential adsorption changed when adsorbed from a competitive environment.
Following modification of samples with adsorbed fetuin-A, the inflammatory effects of fetuin-A were investigated by measuring the concentration of pro- and anti-inflammatory cytokines in response to modified and unmodified samples. Data suggest that elastic modulus influences cytokine secretion at certain timepoints, a result of varied protein adsorption amounts and orientations in response to material stiffness. The addition of a PDA layer demonstrated the potentially cytokine mitigating effect of PDA cell interactions and protein immobilization when compared to unmodified PDMS samples.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Energy Aware Size Interval Task Based Assignment

contributor:
Down, Douglas
Computer Science

subject:
Queueing Theory
SITA
Load Balancing
Electricity Usage

abstract: A thesis based around saving response time costs as well as respecting electrical costs of a homogenous multi-server system.

abstract: In this thesis we consider the impacts of energy costs as they relate to Size Interval Task Assignment Equally--loaded (SITA-E) systems. We find that given systems which have small and large jobs being processed (high variance systems) we could in some cases find savings in terms of energy costs and in terms of lowering the mean response times of the system. How we achieve this is by first working from SITA-E, wherein servers are always on to Electrically Aware SITA-E (EA-SITA-E) by seeing if it is beneficial to make any of our servers rotate between being on and being off as needed. When most beneficial to do so we will turn off some of the servers in question, after this is completed we reallocate some of the jobs that are on the servers that we decide will be cycling to servers that will remain on indefinitely to better use their idle time. This also lowers the mean response time below what we originally saw with SITA-E, by lowering the variance in the sizes of jobs seen by the servers with the longest jobs. These long--job servers are by far the most impacted by the variance of the sizes of the jobs, so it is very desirable to lower this variance. The algorithm contained here can provide benefits in terms of both energy costs and mean response time under some specific conditions. Later we discuss the effect of errors in our assumed knowledge of task sizes. This research contributes methodology that may be used to expand on EA-SITA-E system design and analysis in the future.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The intention of this research is to be able to improve on existing size interval task-based assignment policies. We try to improve by turning servers  off at key times to save energy costs, while not sacrificing too greatly in terms of mean response time of the servers, and in some cases even improving the mean response time through an intelligent re-balancing of the server loads.


title: Maintenance and Reprogramming of Immunoglobulin E Memory

title: Maintenance and Reprogramming of Immunological Memory in Lifelong Food Allergies

contributor:
Jordana, Manel
Health Sciences

abstract:
Food allergy is an IgE-mediated disease affecting up to 10% of those in Western countries. Clinical reactivity to foods occurs following allergen cross-linking of IgE-FceRI complexes on mast cells and basophils causing rapid degranulation and release of vasoactive mediators. While some food allergies are naturally outgrown (e.g. milk and egg), others typically persist for a lifetime (e.g. peanut). For food allergic patients, the standard of care remains as strict allergen avoidance and use of rescue epinephrine upon accidental exposures.
The broad objective of this thesis was to investigate aspects of immunological memory which perpetuate IgE-mediated allergies. In humans, we found that circulating IgE+ memory B cells were extremely rare, positioning memory B cells of other isotypes (e.g. IgG1) as the primary reservoir of IgE responses. IL-4/IL-13 signaling through IL-4Ra was critically required for these non-IgE-expressing memory B cells to replenish the transient IgE pool and, as a result, sensitized mice were fully protected from anaphylaxis upon challenge. Moreover, we demonstrated that IL-4Ra blockade reduced the Th2 dominant cytokine signature while upregulating IFN-y and IL-10. In parallel, we found that allergen-specific B cell responses could be reprogrammed away from an IgE fate. Collectively, this work elucidates key requirements for sustained immunological memory against food allergens and the potential to reprogram its pathogenic fate. These findings may aid in evolving the landscape of food allergy therapeutics.

abstract: Thesis

abstract: Doctor of Philosophy (Medical Science)

abstract: Food allergies, mediated by IgE antibodies arising from B cells, have the potential to last for a lifetime. Currently, the standard of care is strict allergen avoidance and use of rescue epinephrine upon anaphylaxis. The absence of disease-transformative treatments can largely be attributed to an inadequate understanding of the immunological mechanisms through which allergies persist. Therefore, our broad objective was to elucidate the B cell subset which maintains food allergies and the pathway through which IgE is replenished, using both human and mouse experimental systems. We identified that IgE-expressing B cells are exceedingly rare in human circulation, suggesting that allergies are maintained by another B cell subset. Moreover, we demonstrate a critical requirement of a protein messenger (IL-4) that, when absent, prevents the regeneration of IgE and reprograms the underlying allergic characteristics. Collectively, this work uncovers a critical pathway that maintains lifelong allergies and positions IL-4 as a clinically relevant therapeutic target.


title: Addressing GaN Converter Challenges: False Turn-On Issues & Switching Loss Modelling

contributor:
Bauman, Jennifer
Electrical and Computer Engineering

subject: GaN converter, False turn-on

abstract:
Wide bandgap devices are the future of this dynamically changing technological world. Considering Gallium Nitride (GaN) and Silicon Carbide (SiC), GaN has exceptional characteristics that will likely allow it to proliferate greatly in the area of low-and-mid-power power electronic converters. One of the current challenges in this context to completely utilize GaN are the reliability issues, especially false turn-on events, which is a main focus of this thesis. False turn-on due to its momentary short circuit capability deteriorates the converter performance. Furthermore, simple and accurate modeling of GaN device losses is critical to help electronic designers optimize converter designs.
    This thesis focuses on three contributions to help reduce false turn-on events and improve GaN modeling efforts. First, this work uniquely investigates the optimal pulse-width-modulation (PWM) scheme to balance efficiency and false turn-on. The experimental results lead to a recommendation to use a larger negative bias than is currently recommended by device manufacturers. Secondly, the work proposes a new simplified switching loss model with high accuracy that can be used with different gate drive circuits (including negative gate bias voltages) to make it more useful for power electronics design engineers as a tool. And thirdly, since the main contributor to false turn-on events are the parasitic inductances in the switch and on the PCB, this work proposes a new parasitic inductance measurement methodology which can be implemented using only simple laboratory instruments.

abstract: Thesis

abstract: Doctor of Engineering (DEng)


title: Harms Associated with Inhaled Cannabis for Management of Chronic Pain: A Systematic Review and Meta-analysis of Observational Studies

title: Harms Associated with Inhaled Cannabis for Chronic Pain

contributor:
Busse, Jason
Health Research Methodology

subject:
chronic pain
cannabis
harms
systematic review
meta-analysis

abstract:
Background: Cannabis is increasingly used for management of chronic pain; however, the benefits and harms of this therapy remain uncertain. We conducted a systematic review to inform harms associated with inhaled cannabis for chronic pain.
Methods: We searched MEDLINE, EMBASE, PsychInfo, and Web of Science for non-randomized studies reporting on harms associated with inhaled cannabis use, from inception to October 6, 2021. We used random-effects models for meta-analyses and assessed the certainty of evidence using the GRADE approach.
Results: We identified 29 eligible studies enrolling 174,562 participants that reported 145 adverse events. Moderate certainty evidence suggests inhaled cannabis use is probably associated with  dry mouth (prevalence: 56%; 95%CI 49 to 64), thirst (prevalence: 44%; 95% CI 33 to 55), fatigue (prevalence: 38%; 95%CI 31 to 45), nausea (prevalence: 17%; 95%CI 8 to 27), increased appetite (prevalence: 13%; 95%CI 9 to 18), dizziness (prevalence: 10%; 95%CI 6 to 14), diarrhea (prevalence: 9%; 95%CI 3 to 18), confusion (prevalence: 9%; 95%CI 5 to 13), mood changes (prevalence: 8%; 95%CI 4 to 15), hallucinations (prevalence: 7%; 95%CI 4 to 10), amnesia (prevalence: 6%; 95%CI 3 to 11), impaired coordination (prevalence: 5%; 95%CI 4 to 6), and disorientation (prevalence: 3%; 95%CI 1 to 7). Moderate certainty evidence shows that, compared to non-users, inhaling cannabis is probably associated with increased risk of shortness of breath (risk difference [RD]: 7%; 95%CI 4 to 10).
Conclusions: Our review found moderate certainty evidence that dry mouth, thirst, and fatigue are probably frequently experienced with inhaled cannabis use. Several other adverse events are also probable associated with inhaled cannabis use but were less common. Rigorously conducted cohort studies are needed to inform harms associated with inhaled medical cannabis for chronic pain.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Increasing recognition of harms associated with long-term opioid therapy for management of chronic pain has generated enthusiasm for alternatives, including medical cannabis which is often consumed through inhalation. This review assesses the harms associated with the use of inhaled cannabis for management of chronic pain. Among serious adverse events, we found that inhaled cannabis is likely associated with amnesia, disorientation, impaired coordination, hallucinations, confusion, dizziness, chronic wheeze, and shortness of breath. Inhaled cannabis may be associated with palpitations, paranoia, anxiety, and cannabis dependence. The effects of inhaled cannabis on lung cancer, depression, and psychosis were uncertain. Among less serious adverse events, we found that inhaled cannabis is likely associated with thirst, fatigue, increased appetite, nausea, mood changes, diarrhea, and dry mouth. Inhaled cannabis may be associated with red eyes, vomiting, phlegm, asthma, and cough. The effects of inhaled cannabis on euphoria and irritability were uncertain.


title: Some Applications of Open Effective Field Theories to Gravitating Quantum Systems

contributor:
Burgess, Cliff
Physics and Astronomy

subject:
Effective Field Theory
Open Quantum Systems

abstract: Open Effective Field Theories are a class of Effective Field Theories (EFTs) built using ideas from open quantum systems in which a measured sector (the system) interacts with an unmeasured sector (the environment). It is argued that Open EFTs are useful tools for any situation in which a quantum system couples to a gravitational background with an event horizon. The main reason for this is that for any EFT of gravity one generically expects perturbation theory to breakdown at late times (when interactions with the background persist indefinitely). It is shown that the tools of Open EFTs allow one to resum late-time perturbative breakdowns in order to make reliable late time predictions (without resorting to solving the dynamics exactly). To build evidence of their usefulness to these types of gravitational problems, Open EFT approximation methods are applied to two toy models relating to black hole physics.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Open Effective Field Theories are a class of quantum theories in which a measured sector (the system) is used to make physical predictions with, while interacting with an unmeasured sector (the environment). In this thesis arguments are made that Open EFTs are useful for studying gravitating quantum systems, especially when there is an event horizon present (for example in gravitational fields like that of a black hole). Open EFTs are applied to simple toy problems in such settings to illustrate their usefulness.


title: Molecular dynamics investigation of viscoelastic properties of polymer melts

contributor:
Xi, Li
Chemical Engineering

subject:
molecular dynamics
viscoelasticity

abstract:
Polymers and polymer mixtures play such important roles in our lives that it is hard to imagine life without them. Although a lot of progress has been made in the past few decades in our understanding of polymer dynamics and rheology using theoretical, computational, and experimental approaches, there are significant gaps in what is still left to be done. For example, polydispersity is the norm in industrially-produced polymers. However, a lot of the theories that have been propounded are predicated on monodisperse polymers. Most recently, molecular simulations have significantly improved our understanding of polymer dynamics by either validating theories or offering novel insights into their dynamics at the micro-structure level of detail. This thesis also uses molecular simulation to explore three different classes of polymer systems – monodisperse, polydisperse, and polymer-additive mixtures.
Two of the most significant theories of polymer dynamics are the Rouse model describing the dynamics of short and unentangled chains, and the tube and reptation model, which describes the motion of long, entangled chains. The reptation model predicts different dynamical regimes that are marked by distinct time scales and further introduced the concept of an entanglement length Ne – which signifies the length scale at which topological interactions between a test chain and surrounding matrix chains become significant. These distinct time scales have been investigated by various researchers, but the reported values vary with different groups. Here, we devised a protocol for the accurate determination of these time scales. We also calculated Ne using these time scales and compared our results with those reported in the literature. Furthermore, using Rouse mode analysis – a technique that resolves the coupled motion of monomers into distinct and uncoupled modes, we showed that the method can be used to determine Ne, with the values obtained closer to that using monomer displacement at longer time scales.
The computational calculation of the linear viscoelastic (LVE) properties of polymers is very expensive due to the long relaxation times associated with polymers. Using three different methods – Equilibrium molecular dynamics (EMD) via the Green-Kubo relation, non-equilibrium molecular dynamics (NEMD), and corrected Rouse Mode Analysis (cRMA), we determined the LVE properties of polymer melts for both unentangled and entangled chains and compared the uncertainty associated with each of them. Specifically, we demonstrate that the cRMA method, although applicable to only the shorter chains, yielded the lowest uncertainty. Compared to earlier reported results, we also show that, using shorter computational runs, the NEMD gives an acceptable level of accuracy in the calculation of the LVE properties.
Beyond methodology development, this thesis also studied the viscoelasticity of realistic polymer systems of practical interest, including polydisperse polymers and polymer-additive mixtures. We idealized a polydisperse system using a bidisperse model wherein we combined longer chains with shorter chains at different concentration levels. By investigating the individual motion of the different chains, we showed that the dynamics of the longer chains are sped up by the shorter chains, whereas the longer chains impeded the dynamics of the shorter chains, although the nature of the dynamics of the shorter chains was not altered. We also showed that the shorter chains reduce the extent of the entanglement effect of the longer chains using an RMA approach. By using the individual LVE profiles of the long and short chains, we tested a semi-empirical mixing rule for predicting the stress relaxation modulus G(t) of the bulk mixture. We found that a simple mixing rule works well when the shorter chains are the majority while the double reptation model – that assumes a simultaneous relaxation of both the test chains and surrounding matrix chains, does a better job of the prediction when the longer chains are the majority.
We further explored the effect of molecular structure of single-bead additives on the thermo-physical properties, such as the glass transition temperature and Young’s modulus on the polymer-additive mixture. By varying the dimensions of the molecular additive over a range of concentration of the molecular additives, we found that smaller-sized additives are better able to reduce the glass transition temperature Tg and increase the Young’s modulus Y of the mixture due to the improved packing efficiency. On the other hand, larger-sized particles are only marginally able to reduce the Tg. The LVE properties, specifically the zero-shear viscosity of the mixtures showed an opposite trend to the Y, where once again the smaller-sized particles better reduce the zero-shear viscosity. This essentially shows the decorrelation of traditional plasticization markers. A reduction in one property does not imply a reduction in another property and this varies with the dimensions and concentration of the additives. We finally describe our various attempts at developing a multi-bead plasticizer model. For the models we have tried, we tuned the chain lengths of the beads and their interaction with the polymer. Detailed micro-structure analysis and viscoelasticity calculations reveal that they are either incompatible with the polymer, resulting in phase separation or only marginally compatible over a very limited range.

abstract: Thesis

abstract: Doctor of Engineering (DEng)


title: The Courts and Political Speech Rights: A Comparative Study

contributor:
Porter, Tony
Political Science

subject:
Courts
Political equality
Political speech
Campaign finance
Historical institutionalism

abstract: This dissertation contends that to appropriately address the state of political equality and pursue democratic interest(s) in an increasingly commodified world, we must understand the more complex, socio-legal, and interdependent actions, actors, discourse, laws, and ideas which have grown increasingly important within campaign finance judicial out-comes, as these impact political equality and democratic governance. Consequently, this dissertation examines the largely underexplored factors that shape judicial outcomes and practical application of campaign finance policy which are explanatory of the distribution of electoral participatory power. This electoral participatory power is a key indicator of political equality in democratic nation states. The underexplored factors that I examine include corporate identity as an analytical concept and power resource, commodification of political speech, constitutional constraints, intergovernmental dialogue, regulatory ac-tors, and varied judicial and legislative commitments to democracy. To do so, the thesis utilizes and modifies insights from historical institutionalism, power resources models, neopluralism, and dialogue theory literature, to contribute to knowledge about how and why campaign finance policies and electoral participatory power of individuals, groups, and corporations have changed over time through judicial outcomes, practical administration, and related reforms. Through this demonstration, the analysis of this thesis opens up space to explore and identify sources and modes of gradual institutional change within the context of campaign finance judicial outcomes. Specifically, this thesis documents and critically examines the actions, actors, discourse, laws, and ideas which have permeated judicial conflicts in Canada and the United States over several decades and illustrates how they have determined the scope of corporate constitutional rights and freedoms, potential for money in politics, and the distribution of political equality in these two advanced democracies.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: This dissertation examines the sources and modes of gradual institutional change within the context of judicial campaign finance conflicts and related reforms. It argues that the scope of corporate constitutional rights, the commodification of political speech, and the distribution of electoral participatory power are best understood through an analysis that utilizes and modifies insights from historical institutionalism, power resources models, neopluralism, and dialogue theory literature. To demonstrate this, this thesis critically examines the complex, socio-legal, and interdependent actions, actors, discourse, laws, and ideas which have grown increasingly important within campaign finance judicial out-comes, as these impact political equality and democratic governance. Consequently, this thesis illustrates how the scope of corporate constitutional rights and freedoms, potential for money in politics, and the distribution of political equality in the context of elections in Canada and the United States have changed over time, and the reasons for which they have.


title: The Definition, Assessment, and Treatment of Allodynia of the Hand: An International Delphi Study

contributor:
Packham, Dr. Tara. L.
Rehabilitation Science

subject: Allodynia, Hand Therapy, Desensitization, Somatosensory Rehabilitation of Pain, Delphi

abstract:
Introduction
Allodynia is a type of neuropathic pain defined as pain due to a stimulus which does not normally provoke pain. There is little research and conflicting advice. The purpose of this thesis is to provide a summary of the current state of hand therapy knowledge. To accomplish this, a review of the hand therapy literature related to allodynia was conducted, along with the collection of expert opinion utilizing the Delphi survey technique.
Methods
International hand therapy experts were invited to participate in a classical Delphi study. Mixed methods were used to summarize each round and inform any subsequent questioning. Thematic analysis was used to look for patterns of meaning within the written responses. A consensus level of 75% was decided upon a priori for all final recommendations.
Results
Forty-three hand therapists from 15 countries contributed to the fourth and final round. Through the consensus process definitions related to allodynia, and assessments and treatments for allodynia, were explored and recommendations generated. Two themes were identified 1) assessment and treatment decisions depend on the client’s presumed underlying mechanisms contributing to the allodynia as well as psychosocial and functional status, and 2) whether the area of allodynia should be touched or not.
Discussion and conclusions
The literature and our survey results are mixed on whether it is beneficial to touch an area of allodynia. Other aspects related to allodynia such as functional or psychosocial impact are rarely addressed in the literature but were highlighted in our survey. This thesis contributes to the knowledge by presenting: 1) a summary of the current literature, 2) a new consensus definition of hypersensitivity, 3) experts’ recommendations for assessment and treatment of allodynia of the hand and factors to consider when utilizing these, and 4) recommendations for future research, practice, and education.

abstract: Thesis

abstract: Master of Science Rehabilitation Science (MSc)

abstract:
Allodynia is when pain is caused by something that would normally not be painful such as a light touch or mild temperatures. It occurs when nerves become overly sensitive, and if this happens in the hand, it can limit how people use their hand and cause distress. There is little research to guide therapists and conflicting advice in textbooks on how to treat this. To help fill this gap, we conducted four online surveys with hand therapy experts.

We found that expert therapists recommended assessments and treatments that look at how the person with allodynia is functioning and managing the pain. However, they disagreed on whether the painful area should be touched or not. This is important as it influences the advice given to clients and how treatment is delivered. More research is needed to compare approaches and to figure out what factors may influence how people with allodynia may respond to different treatments.


title: Stable Amorphous Calcium Carbonate: Crystallization Behaviour and Stable Isotopes

contributor:
Kim, Sang-Tae
Geochemistry

subject:
Stable Oxygen Isotopes
geochemistry
calcium carbonate
stable carbon isotopes

abstract:
Abstract
	Amorphous Calcium Carbonate (ACC) is a naturally occurring amorphous form of the widely distributed mineral calcium carbonate (CaCO3). ACC has been found increasingly as a precursor phase, calcium storage site, or strengthening structural phase in a wide array of different biomineralizing organisms. An accurate understanding of the widely used classic carbonate-water paleothermometry relies on formation of CaCO3 minerals and associated oxygen isotope effects. Moreover, ACC has oft been pointed to as a possible reason for non-equilibrium isotope effects, also called vital effects, in biogenic carbonates. It is, therefore, vital to understand whether ACC can reach equilibrium with its surrounding solution, as well as the role of ACC precursors in the isotopic composition and evolution of the final crystalline phase they transform into. This study is designed to answer these questions through the precipitation of stable ACC by two methods, the alkaline method (AM) which utilizes high pH to precipitate ACC, and the silica method (SM) which envelopes precipitating ACC particles in silica vesicles to prevent crystallization. These differently precipitated ACCs are then subjected to several different experimental treatments. This is achieved by monitoring the crystallization by X-ray Diffraction (XRD), and isotopic evolution of the ACC precipitates by Isotope Ratio Mass Spectrometry (IRMS) as they age and concurrently crystallize in parent solution, or in 18O enriched re-equilibration solution.
This research indicated a marked difference in the crystallization behaviour, isotopic composition, and isotopic evolution of ACC produced by these two precipitation methods. With the AM method, ACC precipitates (AM-ACC) crystallized more predictably to calcite and maintained δ18O signatures that were slightly lower than the equilibrium CO32- and resisted further isotopic exchange with surrounding solution. We propose that the former is mostly due to an incomplete DIC-water oxygen isotope equilibrium prior to the AM-ACC precipitation and the latter is a result of the high pH of the precipitating solution decreasing the solubility of the precipitated ACC phase, disallowing isotope exchange, and favouring crystallization by solid-state transformation. Conversely, while ACC precipitated using the SM (SM-ACC) yielded much more variable results, both in terms of mineralogical identity upon crystallization, and δ18O values. Isotopic results were much closer to the expected equilibrium δ18O value for calcite, hinting at an expedited oxygen isotope exchange between SM-ACC and parent solution. Furthermore, SM-ACC was capable of isotopic exchange with the 18O enriched re-equilibration solution, a feat corresponding AM-ACC was incapable of. Overall, our experimental results gleaned here that precipitation method or precipitation environment play a critical role in the isotopic evolution of precursor ACC to crystalline CaCO3, suggesting ACC as an important source of the vital effect.

abstract: Thesis

abstract: Master of Science (MSc)


title: Expert and non-expert perceptions of risk: Improving the risk communication of cancer

contributor:
Yiannakoulias, Niko
Geography

subject:
Cancer cluster
Risk communication
Risk perception

abstract:
Cancer clusters constitute geographical areas where the frequency of cancer diagnoses
during a given period of time occur more frequently than expected by chance. Cancer clusters
can impact perceptions of risk and generate significant anxiety in communities. Unfortunately,
cluster investigations rarely yield the answers citizens seek around a definitive cause of cancer
due to the long latency of cancer and other factors. As a result, health officials may appear to be withholding information and not doing enough to address public concerns. Effective cancer risk communication may also be hindered by other stakeholders such as the media, who sometimes sensationalize risks from environmental hazards, which can distort the public’s perceptions of risks. The result may be a community dissatisfied with a cluster investigation’s results, or worse, a community that distrusts local leaders and doesn’t understand the information reported by expert officials.
The four studies comprising this dissertation aimed to summarize key issues with the
communication of and investigation of cancer clusters in Canada; test the impact of different
types of cancer information on risk perceptions; and explore whether individual characteristics
and skills were linked to positive attitudes about coping with cancer risks. An analysis of cancer news coverage and interviews with Canadian public health officials revealed that communities may be receiving inadequate and inconsistent information about cancer risks during cluster investigations. In addition, an experiment and survey revealed information trustworthiness and individuals’ numeracy and health literacy to be important factors shaping cancer risk perceptions and attitudes. This work has significant implications for risk communicators and educators seeking improved methodologies of cancer risk communication and risk education to (1) manage differences in cancer risk perceptions between experts and non-experts (2) enhance public trust in institutions and perceptions of expert competence and (3) inform future educational interventions that promote cancer coping beliefs.

abstract: Dissertation

abstract: Doctor of Science  (PhD)

abstract: Cancer clusters constitute geographical areas where the frequency of cancer diagnoses during a given period of time occur more frequently than expected by chance. Cancer clusters can generate significant anxiety in communities and influence perceptions of personal safety and health. As cluster investigations rarely yield the answers citizens seek around a definitive cause of cancer, health officials may appear to be withholding information and not doing enough to address public concerns. The objectives of this dissertation were to summarize key issues with the communication of and investigation of cancer clusters in Canada; test the impact of different types of cancer information on risk perceptions; and explore whether individual characteristics, expertise and skills were linked to positive attitudes about coping with cancer risks. This work provides insights into the diverse ways that people interpret cancer information and perceive risk and identifies improved methods of conducting cancer risk communication and risk education.


title: Integrated Biorecognition and Dual-Signal Transduction Strategies for Oligonucleotide-Based Biomolecular Detection in Complex Media

contributor:
Soleymani, Leyla
Biomedical Engineering

subject: Biosensors Photoelectrochemistry Electrochemistry

abstract:
PEC bioanalysis represents a unique and dynamically developing methodology that offers an elegant route for sensitive biomolecular detection. Building on the principle of EC analysis, PEC biosensors harness the unique properties of optically active species to enhance analytical performance. Owing to the current based outputs evolved in both PEC and EC bioanalysis, they can be miniaturized and potentially integrated with handheld and portable analyzers, making them uniquely positioned as tools to build effective POC diagnostics.
The commercialization of PEC technology for building POC diagnostics, however, heavily depends on enhancing the stability of the photoelectrodes upon repeated use, lowering the limit-of-detection (LOD) of the PEC biosensor used, enhancing the efficiency of signal transduction and the ability of the device to detect minute amounts of biomolecular target in complex biological matrices. In order to address these constraints, we first developed a new solution-based strategy integrating inorganic semiconductive species (titanium dioxide) in an organic framework to construct photoelectrodes with enhanced signal baselines and adequate stability for the cyclic measurements required in biosensing.
These transducers were subsequently used to investigate the interaction mechanisms (wavelength dependency, coverage density dependency and spatial dependency) between plasmonic NPs (Au) and the photoelectrodes —chosen as model materials—with the goal of enabling predictive dual-signal modulation and enhanced limit-of-detection in PEC biosensors. The understanding gained was used to design a dual-signal PEC transduction strategy—operated at a single excitation wavelength and on a single electrode—to detect nucleic acid sequences in urine without direct target labeling, target amplification or target enrichment. Here, Au NP terminated biobarcodes served as dynamic signal amplifiers that enabled a low limit-of-detection (5 fM), a wide linear range (1 fM – 100 pM), and the ability to discern between single and double base-mismatched nucleic acid sequences. In parallel, we also detail the development of an EC biosensor featuring dynamic DNA motifs, capable of reagentless, sensitive and specific detection of N-PEDv (nucleocapsid protein of porcine epidemic diarrhea virus)—a protein target with emerging global significance—in both buffer (LOD ~ 1.08 μg mL-1) and urine (LOD ~ 1.09 μg mL-1)

Ultimately, this work presents innovations in material architecture and programmable dual-signal transduction that enhance the performance metrics of biosensors; thus, presenting the potential to design POC molecular diagnostics of the future.

abstract: Thesis

abstract: Doctor of Engineering (DEng)

abstract: To address critical limitations in the field of point-of-care molecular diagnostics, it is vital to develop new tools integrating bio-recognition systems with programmable photoelectrochemical and electrochemical signal transduction that enables the design of more effective biosensors. In photoelectrochemical (PEC) systems, plasmonic materials such as gold nanoparticles are often featured to either amplify or attenuate signal response. While there is a significant amount of literature regarding the interaction of gold nanoparticles (Au NPs) with semiconductive systems, the exact nature of the interaction between the two particles has not yet been fully mapped out. In this thesis, we examine various degrees of freedom—including surface coverage density and separation distance—that influence the design of effective photoelectrochemical systems. The understanding gained is further harnessed to design dual-signal photoelectrochemical systems featuring titanium dioxide (TiO2) photoelectrodes and Au linked dynamic deoxyribonucleic acid (DNA) motifs to enable predictive modulation in response to target identification. An electrochemical (EC) analogue featuring structure switching DNA motifs and redox tagged barcodes was also developed. The resultant PEC and EC biosensing assays were critically examined, and their analytical performance was subsequently evaluated in terms of limit-of-detection, sensitivity, and specificity. Ultimately, new classes of bioassays featuring integrated biorecognition and dual-signalling capability for oligonucleotide (i.e., nucleotide sequences and aptamers) based biomolecular detection in urine and saliva were realized.


title: Fabrication of Advanced Organic-Inorganic Coatings Using Biomimetic Colloidal Techniques

contributor:
Zhitomirsky, Igor
Materials Science and Engineering

subject:
Biomedical
Coatings
Polymer
Bile Acid

abstract:
Surface modifications of bone-interfacing biomedical devices can increase their longevity by promoting bond formation and new bone growth, while reducing the toxic effects of corrosion and wear particles. Coatings which contain biocompatible polymers, bioceramics, drugs, and functional molecules are one route to achieve this. Here, a biomimetic approach is developed for the fabrication of poly(ethyl methacrylate) (PEMA) coatings. For the first time it is shown that PEMA can be solubilized in non-toxic solvents by naturally occurring bile acids. Their unique chemical structure and amphiphilicity allows for efficient solubilization of polymer macromolecules.
Advancements in colloidal sciences enable a facile deposition method termed “dip coating” to be utilized. The feasibility of highly concentrated solutions of high molecular mass PEMA was a key factor for film deposition by dip coating. Singular layers or multilayered PEMA films could be deposited. Heat-treated PEMA films provided corrosion protection to stainless steels. This inexpensive and simple technique can be up scaled to larger manufacturing levels, leading to mass production and clinical development of novel coatings for biomedical applications.
Additional challenges in the fabrication of composite coatings by dip coating were successfully addressed using bile acids. To produce high quality composite coatings by dip coating, a stable suspension is required. Particle aggregation leads to uneven coatings, poor adhesion, and weakened mechanical properties. It was shown that bile acids could act as dispersing agents to mediate this. PEMA coatings containing inorganic materials hydroxyapatite, silica, titania, and diamond were fabricated. The inorganic component of the films could be increased to 50 wt.%. Model drugs tetracycline and ibuprofen were used for the creation of drug-loaded PEMA coatings. Lastly, composite coatings containing functional molecules including heparin and nanocellulose were created.
Overall, these coatings provide corrosion resistance to metallic orthopedic implants, while enhancing potential biocompatibility of the device. The biomimetic approach developed in this investigation was motivated by the role of bile acids and bile salts as solubilizers of cholesterol and other molecules within the digestive system of mammals. A solubilization mechanism has been proposed. This work paves the way for the fabrication of future composite coatings containing other high molecular mass polymers, inorganic nanomaterials, and functional materials or drugs.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract:
Biomedical devices have various properties they must possess to perform their function within the body without harming the patient. Coatings applied to these devices can mitigate the body’s response by reducing corrosion, preventing wear, and promoting bond formation. This increases the lifespan of the device and prevents invasive revision surgeries. Advances in materials engineering and colloidal sciences can help achieve these goals.
Materials selection for novel coatings can be inspired by the composition of real bone - consisting of a polymer matrix with embedded inorganic nanomaterials. Additionally, manufacturing techniques that avoid high temperatures are desirable. Therefore, advances in colloidal sciences which enable coatings to be fabricated by a simple and inexpensive method known as dip coating is of paramount importance. This work used natural biosurfactants bile acids to aid in fabrication of coatings for biomedical devices using advanced polymer poly(ethyl methacrylate) and functional inorganic materials.


title: HYPER-RECTANGLE COVER THEORY AND ITS APPLICATIONS

contributor:
Wong, Max
Chen, Jun
Zhang, Jiankang
Electrical and Computer Engineering

subject:
hyper-rectangle cover
cover order
cover length
linear equations system
nonnegativity constraints
non-negative least squares
linear programming

abstract:
In this thesis, we propose a novel hyper-rectangle cover theory which provides a new approach to analyzing mathematical problems with nonnegativity constraints on variables. In this theory, two fundamental concepts,  cover order and cover length, are introduced and studied in details.

In the same manner as determining the rank of a matrix, we construct
a specific  e ́chelon form of the matrix to obtain the cover order of a given matrix efficiently and effectively. We discuss various structures of the  e ́chelon
form for some special cases in detail. Based on the structure and properties of the constructed  e ́chelon form, the concepts of  non-negatively linear independence and non-negatively linear dependence are developed. Using the properties of the cover order, we obtain the necessary and sufficient conditions for the existence and uniqueness of the solutions for linear equations system with nonnegativity constraints on variables for both homogeneous and non-homogeneous cases. In addition, we apply the cover theory to analyze some typical problems in linear algebra and optimization with nonnegativity constraints on variables, including linear programming problems and non-negative least squares (NNLS) problems. For linear programming problem, we study the three possible behaviors of the solutions for it through hyper-rectangle cover theory, and show that a series of feasible solutions for the problem with the zero-cover e ́chelon form structure. On the other hand, we develop a method to obtain the cover length of the covered variable. In the process, we discover the relationship between the cover length determination problem and the NNLS problem. This enables us to obtain an analytical optimal value for the NNLS problem.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Epidemics Without Borders: Divided Germany, the Fight Against Poliomyelitis, and Cold War International Relations, 1945-1965

contributor:
Swett, Pamela
Horn, Martin
History

subject:
poliomyelitis
medical history
Cold War
international relations

abstract:
On the first day of August in 1961, the Health Ministry of the German Democratic
Republic (GDR) announced the closure of the German-German border permanently,
accusing the Federal Republic of Germany (FRG) of neglecting its citizens and failing to
properly administer vaccinations against poliomyelitis.1 This accusation sparked the ire of
the West German and United States media, and the Federal Republic denied that there
were outbreaks. The episode raises questions about common perceptions of healthcare in
East Germany. The thought that East Germany might have an epidemic disease under
control, which still caused problems in West Germany, contradicts the perception that
East Germany lagged behind its western neighbor in every realm.
While recent histories of international relations and healthcare emphasize
collaboration between the US and the USSR, and their Cold War allies in this period, this
dissertation presents a less constructive relationship. Despite the shared goal of polio
control and eradication, East and West Germany used epidemic control as evidence of the
successes of one system of healthcare governance, or the faults of the opponent’s system.
The Berlin Wall announcement was the culmination of almost 15 years of government
competition, speckled with individual collaboration, in the field of healthcare.
This dissertation contributes to literature on healthcare in divided Germany,
narratives which present the history of polio as an “American story,” and scholarship on
healthcare and international relations. It shows how two separate healthcare systems were
1 “East Germany Curbs Travel: Blames Polio,” Chicago Tribune, 1 August 1961, 11.
v
constructed by Soviet and American occupiers with German collaborators between 1945
and 1947. These separate systems, established before the official division of Germany,
laid the foundation for two separate states. During the first postwar polio epidemic in
1947, the United States showed its affluence and experience with polio through a robust
response centered on technological solutions. The USSR, conversely, could not match the
United States’ response due to inexperience with polio and lack of economic resources,
garnering criticism from German citizens and US occupiers. In 1955, the introduction of
Jonas Salk’s injected polio vaccine gave doctors and civilians in the US hope that polio
would soon be a memory, but European responses were much more ambiguous. Albert
Sabin’s forthcoming oral polio vaccine appeared to be a much more promising option to
many physicians due to its ease of administration and cost-effectiveness. When Sabin
chose to field test his vaccine in the USSR, his decision to collaborate with the US’s Cold
War opponent demonstrated significant potential for collaboration. Nonetheless, the
Soviet connections of Sabin OPV led to a crisis in divided Berlin.
The history of polio is not an American story and recognizing the ways in which
the fight against this disease went beyond the national, complicated by political
boundaries but involving recognizable collaboration across those boundaries, helps
expand the historical narrative of poliomyelitis. While vaccine diplomacy was indeed a
form of soft power used in the context of the Cold War, promises of vaccines were not
always received without question, and incorporating a deeper examination of recipient
countries’ discourses helps complicate our understandings of diplomacy and hesitancy.

abstract: Thesis

abstract: Candidate in Philosophy

abstract:
This thesis outlines the ways in which an infectious disease, poliomyelitis, was
treated and prevented in divided Germany between 1945 and 1965, contextualizing
medical history with the political context of the Cold War. The first two chapters examine
the period from 1945 to 1953, when no vaccines against polio were available and
Germany was occupied by the Allied powers. The German healthcare system was
reconstructed differently in the Soviet and American zones. The political beliefs of each
occupying power shaped the resulting systems: socialized and centralized medicine was a
hallmark of the Soviet zone’s healthcare, while the American zone pursued a free market
approach. Chapters three and four explain the introduction of two different vaccines, both
developed in the United States: an injected vaccine created by Jonas Salk, and an oral
vaccine developed by Albert Sabin. The United States championed the Salk vaccine,
while the USSR was an early adopter of the Sabin vaccine. These chapters explain how a
vaccine created in the US became known as a Soviet vaccine, and how this reputation
affected western countries’ adoption of the medical innovation. The thesis concludes that
doctors are not separate from the political contexts in which they live and shows how
political ideology and cross-border rivalry affect healthcare provision.