VictorJuiz/thesis huggingface dataset:
In-situ Visualization and Quantification of Polymer Crystallization under Complex Flows during Foam Extrusion Processing

The crystallization behavior of polypropylene (PP) and poly(lactic acid) (PLA) during foam extrusion processing was investigated via visualization techniques. In the experiments, a tandem extrusion system equipped with a conical converging flow channel and a high temperature/pressure visualization chamber were employed. Using the developed system, effect of processing parameters on crystallization was elucidated. These parameters included the processing temperature, the carbon dioxide content, the flow rate, and the strain rate. The visualized crystallites were quantified based on their light intensities and by the definition of the Crystallinity Index (CI) and the Crystallite Size (CS), where the CI and CS corresponded to the relative crystallinity and the size of crystallites, respectively. Moreover, a correlation was made between the content of the induced crystallites inside the extruder and the cellular structure of the extruded foams. It was verified by visualization that both PP and PLA crystallize during the process even at a temperature above their nominal melting peak point (Tm). The formation of crystallites at a temperature above the Tm was asserted to the strain-induced crystallization. Moreover, a procedure was proposed in order to decouple the effect of the flow rate (corresponded to the strain rate) and the cooling history. A significant enhancement in crystallization kinetics was observed by increasing the strain rate. This crystallization enhancement caused by the increased flow rate became more pronounced at lower temperatures, most probably due to the higher degree of molecular orientation. Adding the CO2 shifted the crystallization temperature to a lower processing temperature due to its plasticization effect, but it accelerated the crystallization kinetics. This clearly explained the decrease in the optimal processing temperature for foaming with an increased CO2 content. It was also confirmed that the induced crystallites during the process had a great effect on the cellular morphology of the resultant foam product.

Keywords: Extrusion Foaming
Flow-induced crystallization
In-situ visualization
Polylactide
Polypropylene
Supercritical Carbon Dioxide
Advisor: Park, Chul B.
Red-Light Tehran: Prostitution, Intimately Public Islam, and the Rule of the Sovereign, 1910-1980

This dissertation investigates the urban life of the red-light district of Tehran, Shahr-i naw, from its inception in the early twentieth century to its erasure after the Islamic Revolution in 1980. “Red-light Tehran” broadens the scope of the literature on modern Islam to the arena of state sovereignty and the governance of precarious subjects. Shahr-i naw is an unlikely place to explore Islam. However, beginning in the early twentieth century in Tehran, the increasingly visible business of urban prostitution and street solicitation, perceived as an unhygienic, immoral and un-Islamic practice, became a site of contestation for larger debates about the role of Islam, in the domain of public. The district serves as a central site for inquiries about the shifting role of Islam in the governance of subjects that were never fully integrated into the political system of the modern post-constitutional state. This exploration of the history of the district remaps the force of religion in Tehran, a city that is so often glossed as a case of state-oriented top-down secularization and subsequent Islamization. In the early twentieth century, Islamic periodicals and physicians of the time anchored on the medico-moral crusade against prostitution and (re)articulated Islam as a disciplinary force, compatible with microbiological sensibilities. In response to mass religious petitioning against street prostitutes in the 1920s, the state evicted prostitutes to a segregated district outside the city gates. In the 1940s, as Tehran grew larger, enveloping the red-light district into the heart of the city, prostitutes returned to the public eye, only this time the point of attractions was their precarious lives and work conditions. This shift in concern intimated the advent of a compassionate impulse and a humanitarian Islamic culture of care. In the 1950s, the state gestured towards closing the site to “rescue” female residents, while simultaneously it experimented with modern “regimes of care,” with minimum expense and maximum ambition, through funding social work projects, and launching “salvation houses.” The district was a sixty-year long sovereign experimentation with regimes of governance, comprising of juridical, economic, welfare, and medical techniques of governance including bodily regimentation, medical regulation, and rehabilitation.

Keywords: Historical Anthropology
Iran
Modern Islam
Publics
State Sovereignty
Urban inequality
Advisor: Tavakoli-Targhi, Mohamad
System-based Approaches for the Enhancement of Catalytic CO2 Reduction Reactions

This thesis focusses on the importance of system design, specifically the engineering of gas, liquid and solid catalyst interactions, in enhancing catalytic CO2 reduction processes. The most impactful contributions of this thesis are: the enhancement of CO2 production rates via morphology-induced mass transport (Chapter 3); the manipulation of local reaction environments to increase electrochemical CO2-to-ethylene production in an H-cell configuration (Chapter 4); the design of an abrupt reaction interface adjacent to a gas-liquid interface for high current and selective ethylene production in an alkaline media (Chapter 5); and the creation of a scalable multi-phase photocatalytic reactor (Chapter 6). While material science and chemistry are essential in the creation and functionality of CO2 reduction catalysts, the overall system surrounding the solid catalyst plays a similar influential role in determining the overall efficiency, product distribution and production rate. By understanding the complex interactions between a solid catalyst, liquid electrolyte and gas reagents/products, the underlying influences of system engineering on catalyst performance can be extracted and improved. Using this approach catalyst surface morphology is revealed to increase limiting current densities multifold by enhancing the natural mass transport effects of departing CO2 reduction products. The pH and CO2 gradients formed at the catalystâ s surface during the reaction similarly influence product selectivity, most notably the ratio between hydrogen, methane and ethylene using copper-based catalysts. Equipped with this understanding, tuning catalyst morphology under differing buffering capacities allowed for traditionally coupled CO2 limitations and electrode pH to become partially decoupled; ethylene production under ambient conditions then improved significantly as compared to a catalytic system void of such considerations. Expanding on this knowledge CO2 reduction catalysts were designed to operate in a highly alkaline environment where the reaction onset potential for ethylene formation was found to be reduced to unparalleled levels. The system design, which manipulated a sub-100 nm diffusion interface, similarly led to half-cell power conversion efficiencies higher than previous efforts at significantly improved production rates.

Advisor: Sinton, David
Experimental Nonlinear Polarimetric Microscopy

Nonlinear optical microscopy is an imaging technique that employs nonlinear optical processes for structural visualization and characterization. The method does not require labelling and provides inherent 3D optical sectioning. It is suitable for noninvasive live sample imaging, and can be applied in disease diagnostics and for clinical use. A wealth of structural information about a specimen is contained in the polarization-resolved nonlinear signal, which stems from the nonlinear susceptibility tensor \txtchin. Information on the \txtchin tensor gives access to the sample ultrastructural properties beyond the diffraction-limited spatial resolution of the microscope. Due to the nonlinear origin of the signals more details can be obtained about the structure, compared to linear optical response; although the complexity of the \txtchin tensor measurement is also increased. Typically, reduced polarimetry methods that are specific to the studied sample have been employed in nonlinear microscopy. The first experimental demonstration of complete 2D nonlinear Stokes-Mueller polarimetric (NSMP) microscopy is presented in this thesis. The NSMP method does not require \emph{a priori} assumptions about the symmetry and the structural organization of the sample. The extraction of all 2D-observable complex-valued molecular-frame {\txtchin} tensor components is performed for the first time in second- and third-harmonic generation (SHG and THG) modalities. Biomedical application of the technique is demonstrated by recovering the SHG {\txtchitwo} tensor of wall muscle from a fruit fly larva and the THG {\txtchithree} tensor of carotenoid crystallites from the root of orange carrot. The presented microscope and the analysis techniques open new frontiers to study the ultrastructure of a wide variety of samples. The general properties of polarization-resolved SHG and THG are presented in terms of the underlying \txtchin tensor properties and useful expressions are obtained; for example, the Stokes parameters and circular anisotropy of the emitted harmonic signals are derived, and new reduced polarimetric imaging techniques are demonstrated based on these expressions. In addition, details of the design, construction and calibration of the polarimetric microscope are provided together with a copy of the NSMP analysis software. Nonlinear Stokes-Mueller polarimetric microscopy can be used for accurate and model-free characterization of the nonlinear susceptibility tensor \txtchin in combination with linear polarimetric properties (e.g.,~birefringence and the degrees of polarization) of a sample, enabling a new generation of complete nonlinear polarimetric microscopy techniques for biomedical imaging and fundamental nonlinear optics research.

Keywords: Microscopy
Nonlinear optics
Polarimetry
Advisor: Barzda, Virginijus
Pressure Induced Quantum Phase Transitions

Quantum phase transitions are among the most intriguing topics in modern condensed matter physics. Interesting physical phenomena usually emerge in the vicinity of quantum critical points, making the investigation of such quantum systems particularly rewarding. In this thesis we present studies related to quantum phase transitions in two compounds, FBBO and Sr3Ru2O7, using hydrostatic pressure as the tuning parameter. Pressure is an ideal parameter to tune the strength of various interactions within the sample by changing the lattice constants, but is known to be very challenging to apply experimentally. Therefore a major effort of my PhD is to find out a consistent and systematic approach to prepare such experiments. FBBO is a neutral organic radical that has been carefully designed to be as metallic as possible at ambient pressure. Nevertheless it is still insulating, and high pressure was required in order to drive this system through the metal-insulator transition. Here, I present strong evidence of the formation of a Fermi liquid ground state under 6.2 GPa [1]. This is the first such observation for a neutral organic radical, after being proposed for decades. In the approach to metallization, we also found intriguing evidence of a low temperature magnetic phase. The c-axis resistivity of the itinerant metamagnet Sr3Ru2O7 has also been measured under pressure. The initial goal was to search for superconductivity, largely because of the interesting unconventional superconducting ground state found in its close sibling, Sr214. In particular, the c-axis conductivity was measured to rule out possible Sr2RuO4 inclusions within the sample. No superconductivity was found up to the highest pressures of 5.8 GPa and 4.7 GPa respectively in the two independent sets of measurements. Instead, we found that the high temperature resistance falls substantially with increasing pressure, unlike what has been reported for Sr214. The metamagnetic transition shifts rapidly with pressure to higher magnetic field. More importantly, power-law analysis at low temperatures at various pressures indicates that the strength of the electron-electron interaction decays rapidly with increasing pressure. This offers a natural explanation for our failure to induce superconductivity at high pressures.

Keywords: Anvil cell
High pressure
Metal insulator transition
Quantum phase transition
Superconductivity
Advisor: Julian, Stephen R
Acute Regulation of Postprandial Lipemia and Chylomicron Production by Glucagon-Like Peptide-1 and Bile Acid Signaling

Postprandial dyslipidemia is a key feature of insulin resistance that involves the overproduction of chylomicron particles from the intestine after a meal, resulting in an excess number of atherogenic lipoprotein remnants. A number of factors are released postprandially that regulate energy homeostasis including gut peptides that signal to the brain and bile acids that act on intestinal receptors. In particular, the anti-diabetic hormone glucagon-like peptide-1 (GLP-1) has received attention as both a gut peptide and CNS neuropeptide. Here I examined the utility of targeting central glucagon-like peptide-1 receptors (GLP-1R) or peripheral bile acid receptors for lowering postprandial lipemia and chylomicron production. The Syrian Golden hamster model was used to study chylomicron secretion, while C57BL/6 mice were employed to examine bile acid profiles and signaling. Injecting the GLP-1R agonist exendin-4 directly into the third ventricle of the brain significantly decreased plasma triglyceride levels as well as the number of chylomicron particles secreted after an oral fat load. These effects were prevented by inhibiting central melanocortin-4 receptors or sympathetic neurotransmission, demonstrating the pharmacological activation of a brain-gut axis. Bile acids were similarly examined as postprandial factors that regulate lipid digestion and lipoprotein release. Intraduodenal bile acid administration decreased plasma triglyceride levels, in part by slowing gastric emptying. Specific targeting of the nuclear farnesoid X receptor (FXR) lowered circulating and intestinal triglyceride levels and increased intestinal markers of fatty acid oxidation. Finally, a potential interplay between GLP-1 and bile acid signaling was observed in exendin-4-treated mice, which displayed altered expression of protein kinase C isoforms (FXR activators) in the gut and upregulation of the rate limiting enzyme for bile acid synthesis in the liver. Altogether, the findings arising from these studies support the potential utility of targeting central GLP-1 and peripheral bile acid receptors in the treatment of postprandial lipoprotein overproduction.

Advisor: Adeli, Khosrow
The Economic And Health Burden Of Chronic Pain In Ontario

Chronic pain is a common problem, affecting 1 in 5 Canadians. Despite this, the burden of chronic pain has not been fully investigated in Canada. This research sought to characterize the burden of chronic pain in Ontario, Canada in three studies. Individuals with and without chronic pain who were identified through the Canadian Community Health Survey (CCHS) were matched using propensity score methods on demographic and comorbidity variables using linked healthcare administrative data. The first study estimated the annual incremental cost to manage chronic pain at $1,742 per person, 51% more than the control group. This translated into $2.8 billion (reference year 2014), or 5% of the Ontario publicly funded health budget. The second study estimated health utilities from the CCHS as a measure of health-related quality of life in people with chronic pain. Utilities are anchored by 0 (dead) and 1 (perfect health), with a difference of 0.03 being clinically meaningful. The mean utility for people with chronic pain was estimated at 0.59 compared to 0.90 for those without. These utilities were lower than those seen with most other chronic diseases including heart disease, diabetes and chronic obstructive pulmonary disease. The third study described mortality by following people until December 2013. There were numerically more deaths in the chronic pain group (2,063 versus 1,722) and a higher death rate for chronic pain as measured by the Kaplan Meier product limit estimator (p

Keywords: Chronic pain
Cost
Cost-of-illness
Health economics
Mortality
Utilities
Advisor: Krahn, Murray
Taddio, Anna
Estimating Grassland Biophysical and Biochemical Properties Using Remote Sensing and Modelling

Grasslands comprise about 42% of the world's plant cover and provide critical ecosystem services to the planet. In recent decades, worldwide grasslands have degraded greatly in terms of area and condition, mainly due to human activities and environmental changes. It is therefore critical to investigate grassland heath and adopt corresponding conservation strategies. Remote sensing is an efficient tool for investigating grasslands, owing to its broad spatial coverage and capability of acquiring data repeatedly. Previous studies have utilized remote sensing to investigate various grassland features, such as disturbances (e.g., wildfire, grazing), species composition, and vegetation properties (e.g., leaf area index, chlorophyll). However, limited by the attributes of remote sensing data (e.g., spatial or spectral resolution) or image analysis methods, there are still research gaps in studying grasslands using remote sensing that warrant further exploration. In this research, multi-source remote sensing data with different spatial, temporal, and spectral features were applied to investigate different grassland properties. Specifically, multi-temporal medium-spatial resolution multispectral imagery acquired by satellite was utilized to investigate a wildfire disturbance on a mixed grassland. Multi-temporal ultra-high spatial resolution multispectral imagery acquired by Unmanned Aerial Vehicle was processed to identify species composition and estimate vegetation properties in a tall grassland using an empirical method. Lastly, multi-temporal high-spatial resolution hyperspectral imagery acquired by manned helicopter was utilized to estimate vegetation properties of a tall grassland using radiation transfer modelling. Results show that grassland features can be accurately retrieved from the chosen imagery, but one should keep in mind that different imagery types have differences in spectral, spatial, and temporal characteristics, and thus are suitable for different research purposes. These research findings provide insights on selecting appropriate remote sensing data and processing techniques for investigating different grassland features, and further contribute to the understanding of grassland ecosystems and grassland conservation.

Keywords: Biophysical and biochemical properties
Fire disturbance
Grassland
Radiation transfer modelling
Remote sensing
Unmanned aerial vehicle
Advisor: He, Yuhong
Understanding Intrinsic Biomolecular Structure with Mass Spectrometry Techniques

Over the past twenty years, since the development of “soft” ionization techniques, there has been a surge of interest in mass spectrometry based protein analysis. It is tempting to make use of mass spectrometry experiments, which are carried out in the gas phase, to elucidate biological behavior. However, the question of whether or not native structure is retained following ionization and transfer to the gas phase has yet to be definitively answered. While mass spectrometrists have made use of a variety of techniques, including fragmentation, spectroscopy, ion mobility, and ion-molecule reactions, to examine the conformation, stability, and energetics of desolvated proteins and complexes, our current understanding of gaseous biomolecules is far behind that of biomolecules in the condensed phases. This dissertation addresses the need for a gas-phase tool which is capable of providing localized conformational detail, and explores the possibility of hydrogen-deuterium (H/D) exchange as a suitable solution. Chapters 2 and 3 show data derived from H/D exchange with subsequent electron capture dissociation, which suggest that key elements of secondary structure, the β-hairpin and the α-helix, may survive electrospray. Chapter 3 also provides evidence that this combination of techniques can identify regions on a peptide that have increased conformational flexibility. In Chapter 4, a study aimed at addressing the relationship between global conformation and deuterium labelling in the gas phase is presented. The work in this thesis builds upon the existing body of gas-phase H/D exchange literature, highlighting strengths of the technique and addressing some of the challenges that users will be faced with regarding the interpretation of these data.

Keywords: Gas-phase peptide structure
Hydrogen-deuterium exchange
Mass spectrometry
Advisor: Jockusch, Rebecca A
Understanding the Effects of Antibiotic Exposure on Host Immune-Microbiota Crosstalk and the Development of Colitis

The etiology and pathogenesis of inflammatory bowel diseases (IBD) remains unclear but involves a complex interplay between host genetics, the environment, the gut microbiota and the mucosal immune system. Antibiotic use in infants and adults is associated with increased risk of IBD development; however, the mechanism by which this occurs is unknown. This thesis project focused on understanding how altered immune-microbe interactions at the gut mucosa contribute to the development of IBD. I hypothesized that perturbation of the gut microbiota following antibiotic exposure would alter the composition of the intestinal microbial community structure, the status of mucosal lymphocytes and subsequently influence susceptibility to colitis. The timing of the antibiotic exposure could have significant effects; therefore, I assessed adult and neonatal treatments separately. Herein, I identified that adult antibiotic treatment of adult mice transiently altered the gut microbiota of both WT and Nod2-deficient animals and that Nod2 was involved in microbial resilience. While antibiotic treatment did not influence the severity of DSS-induced colitis, Nod2-/- mice displayed reduced IL-17A and myeloperoxidase levels and improved mucosal healing following anti-CD3 mAb injection. An altered gut microbiota was associated with increased fecal IgA levels in the absence of Nod2, and transfer of fecal IgA into untreated Nod2-/- mice ameliorated the response to anti-CD3, thereby highlighting the use of IgA as a potential therapeutic mechanism for altering the gut microbiota. In addition, neonatal antibiotic treatment strongly influenced the gut microbial community at weaning and was maintained until day 35 in Nod2-deficient mice. Antibiotic perturbation resulted in worsened DSS colitis in Nod2-/- mice, associated with an increase in colonic Gata3+ regulatory T cells. Understanding how altered immune-microbiota crosstalk increases susceptibility to colitis in a genetically susceptible host (i.e., Nod2-/- mice) will help define such alterations in humans and set the stage for development of preventative and therapeutic manipulation of the microbiota to reduce mucosal inflammation.

Keywords: Animal Models of Colitis
Gut Microbiota
Host-Microbe Interactions
Inflammatory Bowel Disease
Microbiome
T cells
Advisor: Croitoru, Kenneth
Philpott, Dana J