VictorJuiz/thesis huggingface dataset:
Development of Multi‐purpose Lipid Coated PNIPAM Microgels and Techniques for Characterizing Lateral Diffusion in Bilayers
Keywords: pNIPAM
lateral diffusion

The pursuit of a greater understanding of the biological membrane has led to the development of a number of mimetics and probing techniques. This thesis contributes to both of these efforts. Towards the development of mimetics, poly(N-isopropylacrylamide) (pNIPAM) microgels were explored as membrane supports. PNIPAM microgels are “smart” materials that experience a volume phase transition (VPT) at ~32°C, where they undergo a severe loss in volume. The core-shell microgels were synthesized with a low crosslinked pNIPAM core covered by a highly crosslinked pNIPAM shell that was functionalized with exploitable carboxylates. It was shown that a lipid bilayer could be coated on these microgels using either liposomes or bicelles. Specifically, lipid bilayer enclosed microgels made with liposomes (“Lipogels”) were created by using hydrophobically modified microgels, which possessed the ability to sequester liposomes that could ultimately be fused into a continuous bilayer. It was also found that above the VPT temperature, surface decoupled lipid protrude into highly curved structures. Hence, the VPT property could be used to control the curvature of the Lipogel bilayer. These particles could be useful platforms for conducting biophysical membrane studies as well as drug delivery vehicles. Bicelles were also explored as lipid sources for microgel coating, resulting in the creation of “Bicellogels”. Electrostatic attraction between cationic bicelles and unmodified anionic core-shell pNIPAM microgels resulted in the coating of the latter. Astonishingly, the resulting bilayer was made up of only the long chain bicellar lipid. Due to the simplicity of this method, it could be extended to easily coat all types of soft material. The last development on the pNIPAM front involved the coupling of intact liposomes to microgels to create “VESCOgels”. These complexes offer two distinct cargo holds through which temporally distinct release can be achieved. Hence, they could be very useful for applications in tandem release. Lastly, the 31P CODEX NMR technique was adapted to study the lateral diffusion of phospholipids in large liposomes. This technique allows for the measurement of lateral diffusion coefficients of multiple phospholipids simultaneously. This could prove useful for the study of such biologically relevant phenomena as domain formations and drug-lipid interactions.
Resort Urbanism: Understanding the Power, Planning and Politics of Urban Development in Bávaro-Punta Cana, Dominican Republic
Keywords: governance
urban
tourism
planning
Dominican Republic
poverty

In many developing countries, particularly Small Island Developing States (SIDS), coastal tourism impacts local economies and societies in significant ways, and plays an important role in transforming the environment. Rather than simply interpreting the changes that occur around coastal tourist enclaves as impacts, I argue that it is important to recognize the urban nature of spaces proliferating around these enclaves and to understand the role of the actors of coastal tourism in the production of these spaces. Utilizing a case study (Bávaro-Punta Cana, Dominican Republic), my research draws from over one year of fieldwork, including 97 semi-structured interviews with local residents, researchers, and various stakeholders. I examine the power relations between the private sector, local residents, and different levels and sectors of the State in the area’s urban development process. The context of Bávaro-Punta Cana is characterized by the following three issues. First, the newly established local government is generally impotent vis-á-vis other State actors and powerful private sector interests, and is unable to ensure the public good for its citizens. Second, many local residents live in conditions that are worse than traditional urban areas in the country. Third, the private sector has inserted itself as pivotal actor in the development and governance of the newly urbanizing area through practices of corporate social responsibility. Based on my analysis, I refer to the realities of Bávaro-Punta Cana as ‘resort urbanism.’ I utilize this term to illustrate the manifestations of tourism-related urbanization. Drawing from planning concepts, namely splintering urbanism, informality and citizenship, I analyze the physicality and spatiality of urbanization, the processes of urban development, and the rights of citizens and the relations between actors in the production of this new urban space. First, I argue that urban space in Bávaro-Punta Cana is produced as a form of ‘splintered urbanism.’ Second, this space is materially shaped by practices of informality or what is known locally as arrabalización. Last, the area lacks a local governance structure through which residents can adequately make claims to fulfill their basic needs, raising important questions regarding the rights and responsibilities of different actors in urban development.
“All for the Family”: A Case Study on the Migration of Philippine Educated Nurses to Ontario through the Live-in Caregiver Program
Keywords: Nurse Migration
Health Human Resources
Philippine
Internationally Educated Nurses
Live-in Caregivers
Immigration
Domestic Workers
Ontario
Immigrant Nurses
Home caregivers
Nanny
Migrant Workers

Despite evidence that suggests that nurses migrate to Ontario through the Live-in Caregiver Program, no research has been conducted on this group of nurses in Ontario. This study addresses that gap utilizing the transnational feminist concept of “global care chains” in a single holistic case study design to explore the experience of nurses who migrate to Ontario through the Live-in Caregiver Program (2001-2011), and examine the diverse perspectives of stakeholders on issues of rights and obligations of these nurses. Fifteen live-in caregivers and nine policy stakeholders were interviewed, and an analysis undertaken of immigration and nursing policy documents. Findings indicate that familial discourses and perspectives on global social status shape these women’s decision to migrate from the Philippines to Canada, often via a second country (especially Saudi Arabia), as well as their subsequent Canadian experiences. Results are consistent with Rhacel Parrenas’ idea of ‘contradictory class mobility’ that describes the phenomenon of decrease in social status coupled with an increase in financial status among immigrant care workers. As professional women undertaking unskilled work, the nurses’ contradictory class status was reinforced by the emotional labour and domestic work they were required to perform. Furthermore, as temporary workers on a path to permanent residency, their professional integration as nurses was complicated by Canada’s immigration policy and the paradox between the government’s stated short-term goal (to address labour force shortage of live-in caregivers) versus its long-term goal (to ensure the integration of permanent residents). Within this policy paradox immigration policy makers emphasized the short-term obligation of fulfilling labour needs, while live-in caregivers and advocacy groups emphasized the long-term obligations of the Canadian government related to gaining permanent residence status. The lack of congruence between the Live-in Caregiver Program policy and nursing policy concerning internationally educated nurses, as well as prioritization of their familial obligations complicated the process of professional integration for this group of women. Recommendations arising from the study concern the need to bridge these policy gaps and address the shortcomings of the Live-in Caregiver Program to leverage the integration of this group of internationally educated nurses in Canada.
Computational Modeling of Drug Resistance: Structural and Evolutionary Models
Keywords: Drug Resistance
Algorithms
Protein redesign
computational evolution

Active site mutations that disrupt drug binding are an important mechanism of drug resistance. Such resistance causing mutations impair drug binding, thus reducing drug efficacy. Knowledge of potential resistance mutations, before they are clinically observed, would be useful in a number of ways. During the lead prioritization phase of drug development, this knowledge may direct the research team away from candidate drugs that are most likely to experience resistance. In the clinical setting, knowledge of potential resistance mutations could allow the development of treatment regimens, with drug cocktails likely to maximize efficacy. In this thesis I present a structure-based approach to predict resistance and its evolution. This method utilizes a two-pass search, which is based on a novel protein design algorithm, to identify mutations that impair drug binding while maintaining affinity for the native substrate. The approach is general and can be applied to any drug-target system where a structure of the target protein, its native substrate and the drug is available. Furthermore, it requires no training data for predictions and instead predicts resistance using structural principles. Finally, I use approximate force-field calculations from MMPBSA and simple assumptions about the relationship between binding energy and fitness to build fitness landscapes for a target protein under selective pressure from either a single drug or a drug cocktail. I use a Markov-chain based model to simulate evolution on this fitness landscape and to predict the likely evolutionary trajectories for resistance starting from a wild-type. The structure-based method was used to probe resistance in four drug-target systems: isoniazid-enoyl-ACP reductase (tuberculosis), ritonavir-HIV protease (HIV), methotrexate-dihydrofolate reductase (breast cancer and leukemia), and gleevec-ABL kinase (leukemia). This method was validated using clinically known resistance mutations for all four test systems. In all cases, it correctly predicts the majority of known resistance mutations. Furthermore, exploiting the relationship between binding energy, drug resistance and fitness of a mutant, evolution was simulated on the HIV-protease fitness landscape. This hybrid evolutionary model further improves the resistance prediction. Finally, good agreement between these evolutionary simulations and observed evolution of drug resistance in patients was found.
Understanding the Molecular Mechanism of Mgm1 Function in Mitochondrial Dynamics
Keywords: Mitochondria
Mechanoenzyme
Dynamin-related protein
Membrane fusion

Given the debilitating effect that mitochondrial dysfunction has on human health, it is important to understand mitochondrial dynamics that are vital for the maintenance of mitochondrial function, genome, morphology, and quality control. Mitochondrial dynamics result from a balance in mitochondrial fusion and fission. Although the mechanism and regulation of mitochondrial fission are largely elucidated, less is known about mitochondrial fusion. Mgm1 is a protein that mediates mitochondrial fusion in yeast. However, the molecular mechanism of Mgm1 function in mediating mitochondrial fusion is unclear. In this thesis, first, I show that Mgm1 contains a lipid-binding domain by demonstrating that purified Mgm1 has lipid-binding activity and by identifying mutations in conserved residues that abrogate these interactions. Second, I show that Mgm1 assembles into hexameric rings and undergoes nucleotide-dependent structural transitions that, I believe, initiate membrane fusion. Lastly, I demonstrate that Mgm1 exhibits membrane-remodeling activities that are crucial for the tethering and lipid-mixing steps in the membrane fusion event. Together, I propose a mechanistic model of Mgm1 function in mediating mitochondrial fusion that advances the fields of mitochondrial biology, cellular protein-membrane dynamics, and the etiology of neurodegenerative diseases.
Neural Substrates Related to Constructing Novel Events
Keywords: memory
imagination
cognitive neuroscience
hippocampus

This dissertation explored the cognitive processes and neural substrates underlying the simulation and construction of novel mental representations, by manipulating factors influencing construction ability. Across four experiments, subjects constructed novel events by relating multiple cue words to a single context word in order to make a coherent representation. Experiments 1 and 2 tested whether memory deficits related to age and amnesia due to medial temporal lobe lesions affect event construction performance. Both older adults and patients with amnesia showed deficits in event construction, with poorer performance at increasing mnemonic loads. Moreover, older adults’ construction ability was associated with memory performance, suggesting that associative encoding processes are crucial for simulation tasks. Experiments 3a and 3b examined whether semantic congruency between items and context influences event construction and subsequent memory. In Experiment 3a, younger adults constructed imagined events with from cue words that were typically or atypically related to the context word. Atypical events were less coherent, and were rated as poorer in quality and more difficult to construct. Experiment 3b also showed an advantage for typical trials on a cued recall test, suggesting the congruency of an imagined event with prior knowledge has a strong influence on its subsequent retrieval. Experiment 4 used fMRI to determine the neural correlates of imagining. Constructing imagined events activated the hippocampus, medial prefrontal regions, and default mode network regions in comparison to a baseline condition. Moreover, clusters of activation in the anterior hippocampus were positively correlated with construction task performance across all task conditions, whereas activity in the medial frontal poles varied with individual differences in the typicality of imagined events. Posterior hippocampus was associated with the novelty of imagined events, but did not correlate strongly with the anterior hippocampus or task performance. Taken together, these studies suggest that these regions are crucial when constructing a novel imagined event, regardless of the nature of the stimuli. In particular, the hippocampus may be necessary to bind items during the construction process, especially as representations become increasingly complex.
Contentious Cosmopolitans: Black Public History and Civil Rights in Cold War Chicago, 1942-1972
Keywords: African American Studies
Civil Rights
Black History
Public History
Cold War
U.S. Communism
Cultural Workers
Cosmopolitanism
Race
Chicago
Midwest
Mid-20th Century
Southside
United States
Urban
Politics

This dissertation looks at how teachers, unionists, and cultural workers used black history to offer new ways of thinking about racial knowledge from a local level. Numerous efforts to promote and teach this history demonstrated how dissident cosmopolitan political currents from previous decades remained relevant to a vibrant and ideologically diffuse African American public sphere despite widespread Cold War dispersions, white supremacist reactions, and anticommunist repressions. My argument proceeds by demonstrating how these public history projects coalesced around a series of connected pedagogical endeavors. These endeavors included the work of school teachers on Chicago's South side who tried to advance curriculum reforms through World War II and afterwards, the work of packinghouse workers and other union-focused educators who used anti-discrimination campaigns to teach about the history of African Americans and Mexican Americans in the labor movement and to advance innovative models for worker education, and the activities of important cultural workers like Margaret and Charles Burroughs who politicized urban space and fought for greater recognition of black history in the public sphere through the advancement of their vision for a museum. Collectively, these projects expressed important ideas about race, citizenship, education and intellectual labors that engaged closely with the rapidly shifting terrains of mid-20th Century civil rights and international anti-colonialisms. Ultimately, this dissertation offers a social history about how cosmopolitan cultural work in public history and similar forms of knowledge production were at the intersections of political realities and lived experience in U.S. urban life.
Ways of Hearing in Sophokles: Auditory Spaces and Social Dynamics in the Elektra, Philoktetes, Trachiniai, and Oidipous Tyrannos
Keywords: Sophokles
hearing

It has long been known that sight was a crucial component of the fifth-century Athenian theatre. And while that is true, it can also be argued that aurality, the ability to hear and be heard, is an equally important aspect of Athenian drama. This dissertation strives to reclaim a place for hearing in studies on tragedy generally and on Sophokles in particular. Adopting terms from radio theory and media theory, I suggest that Athens was both an acoustic space and an aural community. In the course of an examination of four tragedies, I engage with the following question: how do the characters in these plays hear? Analyzing each play in turn, I show how hearing can occur physically, socially, publically and politically respectively. For Elektra, hearing is a physical and psychic blow; for Philoktetes, hearing is how he connects with the world around him and how he tries to reconnect with people; for Deianeira, hearing is a dangerous phenomenon capable over overturing her own predictions and capable of causing her to lose control of the final shape of her aural reputation; for Oidipous, hearing is an expression of his political status and ultimately a cause of his fall from power. The results of this study show that, in each case, the act of hearing is an invasive process in which the sonant object, mobile and semi-autonomous, can intrude upon new spaces, stage and body alike. This dissertation contributes to a growing body of literature on aurality in tragedy and enhances our understanding of the interconnections between hearing, society, politics, and the individual.
Piezoresistance in Polymer Nanocomposites
Keywords: Piezoresistance
Nanocomposites
Nanoparticles
Electrical Conductivity
Pressure Sensing

Piezoresistivity in conductive polymer nanocomposites occurs because of the disturbance of particle networks in the polymer matrix. The piezoresistance effect becomes more prominent if the matrix material is compliant making these materials attractive for applications that require flexible force and displacement sensors such as e-textiles and biomechanical measurement devices. However, the exact mechanisms of piezoresistivity including the relationship between the matrix polymer, conductive particle, internal structure and the composite’s piezoresistance need to be better understood before it can be applied for such applications. The objective of this thesis is to report on the development of conductive polymer nanocomposites for use as flexible sensors and electrodes. Electrically conductive and piezoresistive nanocomposites were fabricated by a scalable melt compounding process. Particular attention was given to elucidating the role of matrix and filler materials, plastic deformation and porosity on the electrical conduction and piezoresistance. These effects were parametrically investigated through characterizing the morphology, electrical properties, rheological properties, and piezoresistivity of the polymer nanocomposites. The electrical and rheological behavior of the nanocomposites was modeled by the percolation-power law. Furthermore, a model was developed to describe the piezoresistance behavior during plastic deformation in relation to the stress and filler concentration.
Carrefour discursif : Les jeunes issus de l'immigration et l'école franco-ontarienne
Keywords: jeunes
immigration
francophonie
école
ethnographie
sociolinguistique
minorité linguistique

Le contexte social actuel est caractérisé par les effets des processus qu’on attribue à la mondialisation tels que la diversité, l’(im)migration et la mobilité. Ces processus dits mondialisés ont un impact sur les individus, les populations et les institutions ; cela influence les idées de l’éducation en général et de façon plus spécifique la mission et le fonctionnement des écoles de la minorité linguistique francophone. Cette étude de cas ethnographique, sociolinguistique et critique, explore les expériences des jeunes issus de l’immigration dans une école de langue française à Toronto (Canada). Les deux principales questions de recherche sont les suivantes : 1) comment les jeunes issus de l’immigration se positionnent-ils par rapport à l’école de langue française en milieu minoritaire ? ; 2) comment l’école de langue française doit-elle se réinventer pour être plus inclusive de sa clientèle qui est de plus en plus diversifiée aux niveaux linguistique, socio-économique et ethnoculturel ? L’argument central avancé soutient que l’école de langue française en situation minoritaire est en décalage entre la vision et le fonctionnement de la langue à l’école et en dehors de l’école. Ce décalage entre l’idéologie et la réalité linguistique crée des inégalités pour certains membres de la clientèle scolaire plus que pour d’autres, et surtout pour les jeunes immigrants. Les thèmes analysés comprennent l’attrait et le choix des écoles de langue française pour les immigrants (chapitre 5), l’accès au bilinguisme dans le sens canadien (à savoir avec l’anglais) chez les élèves immigrants (chapitre 6) et le rôle de la langue dans les activités des jeunes (chapitre 7). Les résultats de la recherche indiquent que l’accès au bilinguisme en milieu scolaire francophone n’est pas équitable pour tous, que les programmes scolaires ne sont pas nécessairement adaptés aux besoins et aux attentes de la clientèle issue de l’immigration et que les jeunes immigrants rencontrent des obstacles importants à l’école et dans leurs parcours postsecondaires à cause du manque de capital, notamment de capital linguistique. La thèse se termine avec un résumé des implications de la recherche pour les programmes scolaires, pour les rapports école-communauté et pour les parcours postsecondaires chez les jeunes immigrants. Elle fournit également des recommandations pour les divers acteurs intéressés par l’éducation francophone en situation minoritaire.