VictorJuiz/thesis huggingface dataset:
Expanded PLA Bead Foaming: Analysis of Crystallization Kinetics and Development of a Novel Technology

Bead foam technology with a double crystal-melting peak structure has been well established for polyolefins. The double crystal melting peak structure, which is required in the molding stage of the bead foams, generates a strong sintering among the foamed beads and maintains the overall foam structure. In this research, despite the PLA’s poor foaming behavior and its slow crystallization kinetics, we successfully developed expanded PLA (EPLA) bead foams with double crystal melting peak structure and the inter-bead sintering behavior was verified through steam chest molding. For this purpose, the generation and evolution of double crystal melting peak structure in different PLA materials is simulated in a high-pressure differential scanning calorimeter (HP-DSC). The simulation results shows that the formation of double crystal melting peak with different peak ratios can be controlled by varying the processing parameters (i.e., saturation pressure, temperature, and time) during the saturation. The PLA bead foams characterization showed that the high melting temperature crystals generated during the saturation and the low melting temperature crystals formed during the cooling and foaming can significantly affect the foaming behavior of PLA bead foams. Moreover, the crystallization kinetics of different PLA materials are systematically investigated in presence of dissolved gas. It is shown that the different crystallization kinetics (i.e., crystal nucleation and growth rate) that can be induced at various gas pressures can significantly influence the PLA’s foaming behavior (i.e., cell nucleation and expansion behavior).

Keywords: Polylactide
Foaming
Advisor: Park, Chul B.
Girls and Physical Activity: A Multi-Method Qualitative Exploration

The present study examined the multilayered social contexts that foster or hinder adolescent girls’ participation in physical activity. The current study consisted of two phases, prospective interviews followed by focus group discussions. The interviews utilized a guided, life history format with 7 girls of diverse backgrounds, ages 9-15 years old over a 4-year period. Key themes that emerged in the interviews were used to inform the focus group discussions. In total, 4 focus groups discussions were conducted with 13 girls of diverse backgrounds, ages 12-13 years old. Both the interviews and focus group discussions were transcribed and analyzed for themes using a constructivist grounded theory methodology. Data analysis was informed by the feminist theoretical approach, with an emphasis on social and contextual factors. The domains of school, family, peers, and embodied experiences of physicality emerged as facilitative contexts to engagement with physical activity during childhood. During adolescence, however, these contexts became barriers to physical activity. This study suggests that physical activity promotion programs for adolescent girls require multifaceted strategies, with a particular emphasis on the intersection of gender, socioeconomic status, and ethnocultural/racial heritage.

Keywords: adolescent girls
physical activity
Advisor: Piran, Niva
Identification and Characterization of Pseudomonas syringae Type Three Effectors that Alter Auxin Responses.

Plant hormones act in a complex network where their pathways regulate and interact to control different mechanisms, such as development and stress responses. This crosstalk between hormones can be exploited by pathogens to suppress plant defense responses and thereby increase pathogen growth. Pseudomonas syringae pathogenicity is reliant on a Type III secretion system (TTSS) that acts as a specialized injection apparatus to deliver virulence proteins, known as type III effectors (TTEs), into the plant cell cytosol. In my work, I have screened hormone inducible promoter::GUS transgenic Arabidopsis thaliana lines against a P. syringae TTE library in order to identify TTEs involved in the perturbation of hormone signaling in planta. Through this screen I identified two P. syringae TTEs, HopAK1 and HopAL1, both belonging to the same bacterial strain P. syringae pv. maculicola ES4326. I found that HopAK1 can sensitize A. thaliana plants to auxin. On the other hand, HopAL1 activates auxin signaling. Monitoring of auxin signaling was done using transgenic DR5::GUS plants. Both TTEs render the plant susceptible to bacterial infection, highlighting a potential relationship between increased auxin signaling and virulence.

Keywords: auxin
type three effector
plant hormones
Pseudomonas syringae
high-throughput screening
Advisor: Desveaux, Darrell
Yoshioka, Keiko
Pluralizing the Subject and Object of Democratic Legitimation

States are the traditional focal point of democratic legitimation. In the standard model, the institution of the state is normatively privileged: it is the primary object of democratic legitimation, and the national political community is the primary subject. How, I ask, should the standard, state-centric model of democratic legitimation be transformed in light of the presence of substantive jurisdictional conflict and plural political identity? Substantive jurisdictional conflict describes a challenge to the state&rsquo;s authority from non-state institutions that represent a territory which overlaps with a part of or extends beyond the state&rsquo;s territory, make jurisdictional claims that are grounded independently from the state, and do not seek to form states themselves. Plural political identity describes the attachment of individuals to multiple political communities. Under these circumstances, I argue that non-state institutions can be important supplementary objects of democratic legitimation alongside states. The normative rationale for this transformation to the standard model is that adding non-state institutions as additional objects of democratic legitimation will enhance the ability of individuals and political communities to rule themselves. The basic shape of the model I develop is that the strength of competing jurisdictional claims can be assessed by comparing the primary roles of institutions. An account of an institution&rsquo;s primary role describes its contribution to the production of democratic legitimation on behalf of a particular political community or political communities. The primary role of the state, for example, is to enable a project of democratic constitutionalism on behalf of the national political community. I then develop a criterion to guide state citizenries when considering how to respond to the claims of non-state institutions: they should distribute the jurisdiction necessary for non-state institutions to play their primary roles, subject to the qualification that their state&rsquo;s primary role of enabling democratic constitutionalism is not negatively impacted. This approach pluralizes the meaning of democratic legitimation away from a strict association with the state towards multiple institutional locations.

Keywords: Democracy
The State
First Nations
European Union
Advisor: Bertoldi, Nancy
Uncovered Voices: Life Stories of Lebanese Immigrants and their Adaptation to a Northern Ontario Mining Frontier

Immigration has been a prominent aspect of Canada’s make-up, and the effects of immigration on the nation’s economy and society continue to be debated. Largely ignored in the grand narrative of Canada’s multicultural history is the recognition of a first wave of immigrants of Lebanese descent who settled in Canada at the turn of the twentieth century. Little is known about the adaptation process that these immigrants were compelled to navigate during their settlement experience on the newly developed northern frontier of Ontario. These pioneer immigrants were instrumental in building and supporting the northern Ontario communities that would become the foundation for Canada’s mining industry. This thesis argues that the domains of family, work, and community engagement were significant factors in facilitating the process of adaptation and acculturation of early Lebanese immigrants to Canada. Using a narrative phenomenological approach to research, the emphasis was on understanding the roles that family, work, and community played in facilitating acculturation and adaptation of early immigrants. These roles were evident in the life story testimonies of ten descendants of the pioneer immigrants who immigrated to northern Ontario circa 1900. The last surviving elders, children of the pioneer immigrants, ranged in age between 79 and 93 and were born and raised in the northern Ontario mining communities of Cobalt, New Liskeard, Haileybury, Kirkland Lake, Cochrane, and North Bay. Findings were organized under three analytic categories: a) the role of the traditional family b) early immigrants’ role in peddling and entrepreneurship c) community engagement. A documentary film entitled Finding a Silver Lining is included in Chapter Five of the thesis and serves as an annex to the written text. A form of digital storytelling, the film interweaves historical events from the time period between 1900 and 1930 with video clips from participant interviews, archival images, and recorded audio narration.

Keywords: immigration
Lebanese pioneers
Northern Ontario
acculturation
adaptation
Frontier immigrants
Advisor: Cameron, Linda
From Critical to Prophetic Idealism: Ethics, Law, and Religion in the Philosophy of Hermann Cohen

In this study of the nineteenth-century German-Jewish philosopher Hermann Cohen, I argue that Cohen’s revision of Kantian ethics and moral theology is permeated with concepts drawn from and logically contoured by his interpretation of Maimonidean rationalism and Jewish sources, more generally. Through an idealizing hermeneutic, Cohen normativizes certain philosophical problems in post-Kantian philosophy and addresses them under the title of "pantheism" and "positivism". Between both pantheism and positivism, Cohen’s idealism presents a middle path, which I describe as "prophetic idealism", or a philosophy of time and ideality that interprets history, law, and ethical normativity as future-oriented. In other words, "prophecy" intimates a methodological role for temporality in practical philosophy and introduces a new meaning for legality in ethics. Cohen therefore offers a philosophy of Judaism, as a philosophy of religion, by normativizing the idea of prophecy and making it a conceptual model for reason-giving, agency, legal norms and ethical action. By focusing upon the critique of both pantheism and positivism, this dissertation therefore argues that Cohen’s negotiations of nineteenth-century philosophical problems introduces a normative role for Judaism as a public philosophy and the argument concludes by suggesting that Cohen’s philosophy of Judaism is instructive for contemporary public philosophy.

Keywords: Jewish Thought and Philosophy
Ethics
Philosophy of Law
Kant
Neo-Kantianism
German Idealism
Pantheism
Hermann Cohen
Maimonides
Prophecy
Advisor: Novak, David
Gibbs, Robert B.
The Institution of Becoming Canadian: A View From the Margins

Combining historical and ethnographic approaches, this thesis explores the relationship between marginality and the Canadian state's organization of national belonging through the technologies of immigration, settlement and citizenship. In the process it reveals how the lives of people who navigate this institution of becoming Canadian from or into marginalized social positions are shaped in complex ways by the relations of ruling underpinning the nation as a whole, such as colonialism, capitalism, and patriarchy. Data-gathering and analysis proceeded from the standpoint of people whose religion, sexuality, "race", gender, or class positioned them in the margins of a textually mediated and hierarchical policy matrix that justified either their outright exclusion or else inclusion on certain conditions. The impact of this arrangement is queried and we find that, while the fact of being Canadian often leads to improvement in life quality, this is in addition to—or even in spite of—the institutional process of becoming Canadian. The institutional process, by contrast, was found to cause things like downgrading, separation, fear, and changed beliefs and behaviours. The study also examined how people deal with this system, including the purposeful acquisition of knowledge or skills, and reliance on support networks among family, friends, and fellow migrants. Finally, some strategies of mitigation (e.g. rule-breaking) are explored. The study concludes by contrasting the institution of becoming Canadian against a universalist philosophy premised on "global citizenship" and the possibility of a world without borders. Unsurprisingly, there is considerable distance between them, but this contrast reveals inspiring areas for resistance, action and change.

Keywords: immigration
citizenship
settlement
Canada
Advisor: Burstow, Bonnie
Kinematic and Temporal Variability in Healthy and Disordered Swallowing

The works contained in this dissertation were motivated by a desire to better understand the variability of patient performance on videofluoroscopic assessments of swallowing. Specifically, the variation present in kinematic and temporal measures of swallowing was investigated in three main phases: narrative literature review, healthy swallowing, and disordered swallowing. The primary goals were to identify which factors explain (or do not explain) variation, to develop methods to control for variation and to investigate the association between swallowing physiology and swallowing impairment. The literature reviews revealed wide ranges of variation for kinematic (Chapter 2) and temporal (Chapter 3) measures of swallowing in the existing literature on healthy deglutition. The kinematics (Chapter 4) and timing (Chapter 5) of swallowing were investigated in a prospectively collected sample of young healthy participants stratified by height. One main objective was to investigate the impact of participant size on physiological parameters of swallowing. Finally, kinematic and temporal measures of swallowing were investigated in a sample of patients referred for swallowing assessment (Chapter 6) to explore associations between swallowing physiology and impairment. The findings of this dissertation make several unique contributions to the dysphagia literature. It has demonstrated that inherent variation appears to exist in physiological measures of both healthy and disordered swallowing. Further, when certain sources of variation are controlled (such as participant size), men and women do not demonstrate significant differences for any of the parameters tested. Importantly, this work has demonstrated that participant size impacts the expected extent of hyoid excursion and that this variation can be controlled through normalization of hyoid movement to internal anatomical scalars. Two temporal variables trended toward detecting functional swallowing impairment. Finally, this dissertation provides the first set of normative reference values for parameters of swallowing with an ultra-thin liquid barium. Limitations are acknowledged and future work is suggested.

Keywords: swallowing
dysphagia
deglutition
videofluoroscopy
variation
Advisor: Steele, Catriona
Quantitative Behavioral Analysis of Thermal Nociception in Caenorhabditis elegans: Investigation of Neural Substrates Spatially Mediating the Noxious Response, and the Effects of Pharmacological Perturbations

The nematode Caenorhabditis elegans possesses a relatively simple nervous system of only 302 neurons, but is able to perform an impressive range of complex behaviors. This dissertation aims to understand the neurobiology of behavior by quantifying, at the systems-level, the sensorimotor response to carefully controlled stimuli. Through neuronal or genetic perturbations to the system, we can begin to uncouple the behavior from the underlying circuitry. The behavior studied here is thermal nociception, an escape response designed to protect an organism from potential tissue damage or harm from noxious heat. Vertebrates and invertebrates alike possess sensory neurons called nociceptors that detect noxious stimuli and relay the stimulus information to elicit an appropriate escape response. C. elegans is known to perform a reversal or forward response when presented with noxious stimuli at the head or tail, respectively. In this work, we develop a novel thermal stimulus assay with precise spatiotemporal control of an infrared pulse that targets small regions along the worm to spatially dissect the noxious response. We comprehensively quantify the nociceptive behavior, and identify key metrics that scale with intensity, such as speed in the escape state and the probability of certain behavioral states after the stimulus. Furthermore, we have mapped the behavioral receptive field of the worm along its body, and show a previously unreported probabilistic midbody behavior distinct from the head and tail responses. Surprisingly, the worm is able to differentiate localized stimuli at the midbody that are as close as 80 microns. We identified PVD as the thermal nociceptor for the midbody response using calcium imaging, genetic ablation and laser ablation. This suggests PVD could be used as a model to study spatial discrimination at the level of a single nociceptor. This spatial specificity further extends to pharmacological perturbations of the system. In particular, the application of clinically used painkillers to the worm results in a knockdown of this nociceptive response, but does so in a spatially specific manner. These results are promising for future studies building upon the techniques developed here, as they evidentiate the use of C. elegans as a model organism to study pain.

Keywords: Thermal nociception
Biophysics
Quantitative behavioral phenotyping
Advisor: Ryu, William
Infants at Risk for Autism Spectrum Disorder: Gestures in Infants and Mothers

Abstract Infants with an older sibling diagnosed with an autism spectrum disorder (ASD) have a twentyfold increase in risk of developing ASD. Deficits in gesture use are among the first signs of impairment in infants later diagnosed with ASD. Typically, infants develop gestures incidentally in the context of social interactions with their parents. However, infants at risk for ASD may not acquire gestures within these natural interactions. The first purpose of this research was to determine whether infants at high risk for ASD show patterns of communicative and play gestures that are delayed and/or different relative to low-risk infants. The second purpose was to compare mothers of infants at risk for ASD with mothers of infants at low risk for ASD in their use of gestures, gesture strategies, and prompts. Seventeen 15-month-old infant-mother dyads were recruited from a longitudinal study of the emergence of autism symptoms in infants with an older sibling with ASD (high risk for ASD, n = 8; low risk for ASD, n = 9). Infant gestures were examined in three contexts: during clinical assessment, during naturalistic play with their mothers, and by parent report. Maternal gestures and gesture-related behaviours were recorded during the play interaction. Infant and maternal gesture behaviours were later coded from video. High-risk infants showed different patterns of gesture use relative to low-risk infants. In clinic and home contexts, high-risk infants: (a) used gestures that were not directed to a communicative partner more often than low-risk infants, and (b) showed specific deficits in the use of deictic and joint attention gestures. In addition, high-risk infants: (a) demonstrated fewer symbolic play acts at home, and (b) had a smaller inventory of communicative and play gestures by parent report. Mothers of high-risk infants used more play gestures, but were otherwise no different in their gesture behaviours from mothers of low-risk infants. This research demonstrated that, at 15 months of age infants at risk for ASD showed delays and differences in gesture use despite receiving typical gestural input from their mothers. The patterns of these deficits may be important in early identification and could inform intervention practices.

Keywords: autism
ASD
Gestures
Infants
at-risk
mothers
Advisor: Girolametto, Luigi
Development and Characterization of Nickel and Yttria-stabilized Zirconia Anodes for Metal-Supported Solid Oxide Fuel Cells Fabricated by Atmospheric Plasma Spraying

Research was performed on the development of relationships between the microstructure of nickel and yttria-stabilized zirconia (YSZ) coatings and the processing parameters used for their deposition by atmospheric plasma spraying (APS). Research was also performed on the development of relationships between the microstructure of plasma sprayed Ni-YSZ coatings and the electrochemical performance of metal-supported solid oxide fuel cells (SOFCs) incorporating these coatings as anodes. Three APS processes were used to deposit Ni-YSZ coatings: dry-powder plasma spraying (DPPS), suspension plasma spraying (SPS), and solution precursor plasma spraying (SPPS). These processes differ in the form of the feedstock injected into the plasma. The composition of the Ni-YSZ coatings deposited with each spray process could be controlled through adjustment of the plasma gas composition and stand-off distance, as well as adjustment of feedstock properties including agglomerate size fraction for DPPS, NiO particle size and suspension feed rate in SPS, and the enthalpy of decomposition of the precursors used in SPPS. The porosity of the Ni-YSZ coatings could be controlled through the addition of a sacrificial pore forming material to each feedstock, with coating porosities up to approximately 35% being achieved for each coating type. Metal-supported SOFCs were fabricated to each have anodes deposited with a different plasma spray process, where all anodes had nominally identical composition. The microstructures obtained for each anode type were distinctly different. SPPS led to the most uniform mixing of the smallest Ni and YSZ particles. These anodes most resembled typical structures from anodes fabricated using conventional methods. It was found that the polarization resistance, Rp, associated with the high frequency (&gt; 1 kHz) range of the impedance spectrum correlated to the three phase boundary length (TPBL) density of each anode, with lower Rp values corresponding to higher TPBL densities. It was also found that the Knudsen diffusion coefficient and effective ordinary diffusion coefficient of the porous anodes correlated with the Rp associated with the low frequency (&lt; 1 kHz) range of the impedance spectrum. Therefore, the impedance spectrum can be used to compare microstructural differences among plasma sprayed Ni-YSZ anodes.

Keywords: solid oxide fuel cell
atmospheric plasma spray
Advisor: Kesler, Olivera