VictorJuiz/thesis huggingface dataset:
A New Perspective on the Wetting of a Surface by the Drops of an Emulsion
Keywords: Film instability
Heterogeneous nucleation
Interference contrast microscopy
Polymer confinement
Thin film drainage
Wetting

Spinodal wetting theory of a drop on a solid substrate requires that a bridge be formed, which connects the drop and the substrate, and that this bridge grows laterally to complete the spreading process. Here, we show that due to trace solubility, dissolved drop phase can diffuse to the solid surface, and then nucleate and grow in the form of islands. Coalescence between the drop and the islands completes the wetting process. In this work, experiments involving buoyancy-driven motion of glycerol drops in viscous suspending media, towards a flat substrate such as mica or SU-8 were conducted. The film drainage dynamics and wetting behavior were captured using reflection interference contrast microscopy (RICM). When glycerol drops settled in silicone oil , towards a mica substrate, the film drainage ceased due to polymer confinement at film thicknesses of about 10 nm. Further, glycerol islands were found to emerge at the silicone oil/mica interface. Eventually, coalescence between the glycerol drop and the glycerol islands completed the wetting process. The experiments were then extended to small-molecule media such as castor oil, and in the presence of a non-ionic surfactant called Span 80. When glycerol drops settled in castor oil towards a plasma-treated SU-8 substrate, glycerol islands were found to nucleate and grow. The addition of Span 80 to castor oil caused dramatic nucleation of islands with a foam-like cellular structure owing to a reduction in the nucleation barrier. The stability of high curvature islands in the presence of a low curvature drop was addressed by considering an extended Kelvin equation that accounts for disjoining pressures near the contact line. This equation predicts that while the solubility associated with a curved surface is higher than that of a flat surface, the solubility is significantly decreased near the contact line, provided the surface forces are attractive between the substrate and the drop phase. Using this hypothesis, we developed mathematical models corresponding to influx at the contact line and outflux over the curved surface of an island. Our stability analysis showed that during the approach of a drop towards an attractive substrate, islands can continuously grow.
Elucidating and Harnessing Atomistic Processes to Design Nanoparticles
Keywords: capping agent
classical crystal growth theory
nanorod
supersaturation
surface diffusion
vicinal facet

Crystals are known to grow nonclassically or via four classical modes (the layer-by-layer, dislocation-driven, dendritic, and normal modes). While the field of nanoscience considers this framework to interpret inorganic nanoparticle (NP) growth, how many NPs grow remains enigmatic, suggesting that this framework may be incomplete. This thesis develops approaches to investigate NP growth, expands this framework, and applies these insights to design NPs. Supersaturation is the fundamental parameter driving crystal formation but generally cannot be measured during colloidal NP growth. We develop a methodology that relates the optical properties of growing NPs to the supersaturation dynamics underlying their growth. Using this approach, we investigate the seed-mediated growth of Au nanocubes, revealing a triphasic sequence of supersaturation dynamics, which is more complex than previously imagined. Our approach can be used to predict NP growth profiles and identify supersaturation-associated shape evolutions, providing insight towards rational design. We next studied the solution-phase growth of pentatwinned Au nanorods without Br, Ag, or ammonium surfactants. Lower supersaturation conditions favored anisotropic growth, which appeared at variance with the known modes. The vicinal facets of these nanorods (situated inbetween {100} side-facets and {111} end-facets) facilitated {100}-to-vicinal-to-{111} adatom funneling. Our results were consistent with nanorods growing via two modes simultaneously: radial growth occurred via the layer-by-layer mode on {100} side-facets, whereas asymmetric interfacet adatom migration to {111} end-facets mediated longitudinal growth. The latter supports a fundamental growth mode in which monomer deposition and integration occur on different facets. To expand the design capabilities for colloidal NPs, we developed the transitory synthesis pathway, which uses transitory ligands to spatiotemporally separate synthesis from capping. Transitory synthesis uses simple benchtop chemistry to enable for the efficient, modular design of NPs and their final surface features. We experimentally demonstrated >100 distinct NPs, including heterostructured multimetallic compositions and many previously unattainable designs. Lastly, we conducted proof-of-concept studies towards the development of NP timers integrated within contact lenses. Based on NP colloidal stability, these indicators passively use discrete, programmable color transitions to prompt patients to dispose of their lenses after the recommended lifetime. Moreover, this approach is compatible with industry standard sterilization and manufacturing practices.
Energy Transfer in Emerging Triplet Fusion Platforms: Towards Functional Photon Upconversion Technologies
Keywords: nanocrystal
photophysics
spectroscopy
upconversion

While the concept of converting low-energy photons to higher energy photons may sound fictional from a thermodynamic view, triplet fusion upconversion achieves this in a trade of photon number for photon energy. This incoherent photon upconversion process is a spectral management strategy that yields higher energy photons from the energetic input of two or more low-energy photons. Using the process of triplet fusion, energy is stored in the long-lived triplet excited states of molecules until a suitable energy outlet is found. Combing the energy from these two triplet-excited chromophores yields an emissive singlet with more energy than the original input photons. In this thesis, I explore the development of triplet fusion upconversion platforms, using spectroscopic insight to inform key application targets.I introduce the concepts fundamental to understanding triplet fusion upconversion—outlining how triplet excited states are prepared, how energy is transferred between them, and how the energy from these triplets may be combined in a useful way. I provide the theoretical background required for understanding spectroscopic observables and highlight focal points of the quantum mechanical principles controlling triplet exciton interactions. Then, I report my proof-of-concept demonstration of nanocrystal-sensitized upconversion photochemistry. I focus on the process of endothermic triplet sensitization using a novel class of ultrasmall lead sulfide nanocrystals. Spectroscopy of this system reveals the quantitative benefits of using nanocrystal sensitizers with long excited-state lifetimes. Additionally, I improve the performance of these vulnerable nanocrystal sensitizers by installing a monolayer, self-limiting shell. Mitigating non-radiative losses in these nanocrystals pays immediate dividends for triplet sensitization and upconversion, highlighting the need for top-to-bottom design. Finally, I focus on the process of triplet fusion itself, investigating the triplet fusion kinetics of a structurally rigid tetracene dimer. Comparing this novel emitter with monomer controls reveals incisive differences in the usage of triplet excitations after sensitization, hinting at a key concentration dependence. Using spectroscopy as a tool to understand the key photophysical targets for nanocrystal-sensitized triplet fusion upconversion applications, I provide an outlook for future work in this domain. I especially focus on systems that would benefit from the synergistic design rules identified in this thesis.
Biodegradable Polyurethane Hydrogels for Sustained Growth Factor Delivery Intended for Treatment of Ischemic Conditions
Keywords: Biodegradation
Biomaterial
Growth Factor Carrier
Hydrogel
Immune response
MRI

The development of a treatment for ischemic conditions has been hindered by the lack of appropriate growth factor delivery vehicles, the limited number of effective agents, and the inability to assess the efficacy of the agent in clinical trials. An MRI-trackable injectable microsphere growth factor delivery vehicle, containing low-inflammatory polyurethanes, referred to as D-PHI polymers, is proposed for treating ischemic conditions in this thesis. The carriers were developed with the design challenge that growth factors have short half-lives in the body but are necessary for a few weeks to ensure cell survival, proliferation, and migration. In order to avoid rapid uptake by phagocytic cells and to facilitate the extracellular delivery of growth factors, microspheres of specific sizes and morphologies were fabricated. The chemistry of the D-PHI polymer was modified to achieve a fast bioresorption rate, whereby it can be quickly reabsorbed once the growth factor has been released. In order to predict the biodegradation of a family of novel crosslinked D-PHI hydrogels, an accelerated erosion test was developed. In vitro methods for evaluating the encapsulation, stability, and release of proteins from such hydrogels were developed and validated. Specific steps were taken to maintain the activity of the protein (i.e. vascular endothelial growth factor (VEGF)) during fabrication, storage, and use of the growth factor carriers. A sustained release of VEGF was observed over a two-week period from the hydrogels, and the released VEGF increased the proliferation of cells. To dampen the inflammation associated with a foreign body response in tissue and prepare it for revascularization, polyurethane-based D-PHI materials were used. These materials exhibited inherent immune-modulatory properties. For the purpose of tracking the hydrogel in rodents non-invasively, an MRI contrast agent was developed. The T1 contrast of manganese porphyrins bound to hydrogels was measured using this strategy. This thesis contributed to the development of an injectable polyurethane D-PHI hydrogel, which facilitates the slow release of pro-angiogenic VEGF and provides a versatile MRI-active platform. The combination of these technologies can provide a specific set of growth factor carriers that may be applied to the treatment of ischemic conditions and other soft tissue injuries where pro-regenerative immune control is important.
Perpetuating Precarity in Theory and in Practice: A Case Study of Work-integrated Learning in the Non-profit Sector in Northern Canada
Keywords: experiential education
human capital theory
human development and capabilities approach
inequality
non-profit organization
work-integrated learning

Work-integrated learning (WIL) is a process of curricular experiential education within a workplace or practical setting and is believed to give students “the skills and experiences they need to start a well-paying career after they graduate” (Trudeau, 2017). WIL is portrayed as a win-win, yet this research suggests that WIL perpetuates precarity and deepens inequalities between students, between different types of employers, and between geographic regions. Using the Human Development and Capabilities Approach (HDCA), this study investigated how eight diverse non-profit organizations (NPOs) in northern Canada are positioned to support students to develop personal agency through WIL. Most WIL research is urban-centric, focused on for-profit industries and framed within Human Capital Theory (HCT), making this study an outlier. Using a case study approach underpinned by critical and social realism to inform research methods, this study explores the ways in which WIL enables and constrains the development of agency at individual, social, and institutional levels. The role of learning partners, the structure of WIL and the presence of social actors (industry associations, regulatory bodies, and unions) were examined as conversion factors. The research is based on semi-structured interviews with twelve non-profit staff and volunteers, ten faculty and administrators, and institutional document analysis. Content analysis was implemented by organization to identify themes. The research shows inconsistencies in current approaches to WIL. While NPOs are committed to student development, theoretical fragmentation within non-profit contexts combined with constraints in the post-secondary environment compromise student learning. Students and learning partners are poorly prepared and equipped for WIL. Furthermore, the increasingly precarious positioning of NPOs within the labour market threatens their ability to offer students (future) decent work. The institutional and policy environments that undergird WIL do not acknowledge the distinctness of non-profit organizations within a neoliberal economy and this makes invisible other dimensions that affect decent work, such as the regulatory environment, collectivization, and the “contracting regime.” To ensure well-paying jobs, these factors must be addressed. This research also recommends that WIL be evaluated with greater emphasis on social and institutional conversion factors, and that future studies of WIL use HDCA, rather than HCT.
Amīr ʿAbd al-Qādir al-Jazāʾirī (d. 1883): Mystical Hermeneutics, Theology and Metaphysics in His Kitāb al-Mawāqif (“The Book of Mystical Halts”)
Keywords: Ash'arism
Islamic Reform
Metaphysics
Modernity
Qur'an
Sufism

This dissertation examines the Sufi revivalist theology of Amīr ʿAbd al-Qādir al-Jazāʾirī (d. 1883) through a close study of his magnum opus, Kitāb al-Mawāqif fi baʿḍ ishārāt al-Qurʾān ilā’l-asrār wa-l-maʿārif (“The Book of Mystical Halts Concerning Some Subtle Qurʾānic Allusions to The Esoteric Mysteries and Divine Truths”). Although considerable research has been conducted on ʿAbd al-Qādir’s political resistance against the French colonial invasion of Algeria, his enormous influence on nineteenth-century Sufi revivalist discourse remains understudied and poorly understood. Over the past decades, however, a small but growing niche of scholars begun to pay closer attention to ʿAbd al-Qādir’s Sufi mystical teachings. The literature on Kitāb al-Mawāqif, however, is conspicuously scarce. We only have scattered essays on some salient themes that emerge in Kitāb al-Mawāqif or the influence of Ibn ʿArabī’s (d. 1249) mystical doctrines on ʿAbd al-Qādir’s thought. As the first in-depth study of Kitāb al-Mawāqif, my dissertation fills a long-existing gap in modern scholarship. By closing examining the Sufi Qurʾānic hermeneutics, mystical theology and revivalist discourse of ʿAbd al-Qādir, I offer a deeper glimpse into his mystical universe and his unique contributions to early modern Sufi revivalist discourse. As I argue, ʿAbd al-Qādir develops his Sufi revivalist discourse against the backdrop of his critique of Ashʿarī scholastic rationalism (kalām). Rather than turning to rationalism for answers, he seeks to curb what he considers a subversive Islamic rationalism that competes rather than submits to the authority of Revelation and Sufi mystical knowledge.
Sample-Complexity Optimality Under Local Differential Privacy and Related Models
Keywords: differential privacy
estimation
information complexity
learning
local

This work explores the sample complexity of estimation and learning tasks under local differential privacy (LDP), an especially strong approach to differential privacy which does not rely on any trusted party to guarantee privacy. We give a new characterization of the sample complexity of answering statistical (linear) queries under non-interactive LDP in terms of the $\fnorminf$ norm, showing that a slight generalization of the well-studied factorization mechanism achieves, in polynomial time, nearly optimal sample complexity for each specific workload of queries. These results are obtained by leveraging information theoretic bounds for LDP and applying them together with geometric techniques which allow us to construct hard distributions for answering statistical queries. We extend these ideas to obtain characterizations of both agnostic learning and and agnostic refutation under non-interactive LDP in terms of the $\fnorminf$ norm, and derive, by consequence, a sample-complexity equivalence between the two tasks. We also give a characterization of realizable refutation in terms of a factorization norm which we define. A matching upper boud is given for realizable refutation, implying that realizable refutability implies realizable learning. We explore other techniques for obtaining characterizations of local privacy tasks, including an approach which combines a mutual information bound for differential privacy with an information complexity lower bound borrowed from communication theory. We also consider relationships between local privacy and data-access models which turn out to be closely related. In particular, we demonstrate an equivalence between the sample complexity of learning under sequential LDP and the sample complexity of learning under single-intrusion pan-privacy. Finally, we demonstrate an equivalence between the sample complexity of agnostic learning under non-interactive LDP and the query complexity of agnostic learning under the adaptive correlational statistical query model.
Examining the Relationship Between the Natural Environment and Outcomes Related to the Mental Health and Well-Being of Residents and Care Staff in Long-Term Care Homes
Keywords: long-term care
natural environment
nurses
nursing home
personal support workers
residents

Introduction: Natural environments (NEs) in healthcare design are thought to promote health. However, empirical research on the NE in long term care (LTC) has been limited; the degree of rigour is mixed, focusing mostly on residents, with little research on care staff (e.g., personal support workers and nurses). Aims: The aim of this investigation is to examine the relationships between the NE and the mental health and well-being of residents and care staff in LTC homes using a rigorously developed survey to standardize an approach to the evaluation of the NE in LTC homes. The three research questions (RQ) addressed are (1) How is the NE conceptualized in healthcare literature? (2) How can the NE design, usage and exposure be evaluated rigorously in LTC homes? (3) What are the associations between the NE and the MH&WB in residents and care staff? Methods: This is a cross-sectional, Multiphase Mixed Method study which included a scoping review, a modified Delphi technique, cognitive debriefing interviews, psychometric evaluations, and multilevel modelling. Key findings: A conceptual framework was developed that comprised five interdependent themes on the NE in healthcare, relating to its definitions, processes, usages, people’s opinions, and effects—all of which are shaped by the NE’s physical and programmatic design. The framework informed the development of the Natural Environment Survey for Long-Term Care (NESL), comprised of three parts: evaluating NE design, residents’ NE usage and exposure, and care staff’s NE usage, exposure, and perception. The application of the NESL in 83 units across 27 LTC homes identified statistically significant associations between the NE and residents’ responsive behaviour in secure units and between the NE and care staff’s work-related stress, burnout, and turnover intention in secure and non-secure units. Significance: The framework complements the conceptual work on the NE to date and emphasizes NE’s complementarity to the biomedical healthcare system. The NESL advances research by providing a strong conceptual and empirical base for future development and standardization. Findings from this research are likely generalizable to LTC settings in other jurisdictions and have potential utility for researchers and decision-makers who are transforming LTC.
Quality of Care and Long-term Outcomes of Active Surveillance: Gaining Insights from Population-level Perspectives
Keywords: Active surveillance
Long-term outcome
Population-based study
Prostate cancer
Quality indicator
Quality of care

Active surveillance (AS) for low-risk prostate cancer (PC) is evolving as an internationally recognized standard of care and is recognized by major urological associations as a preferred treatment option. AS is increasingly used worldwide, yet research on variations of quality of care during AS is lacking, and compliance with AS guidelines is largely unknown at the population level. The aims of this research were to develop quality indicators (QIs) for AS, evaluate the quality of care for patients on AS using those QIs, and estimate long-term oncological outcomes after initial AS. A first study aimed to develop national consensus-based system-level QIs for evaluation of AS care among patients with low-risk PC. A second study aimed to critically apply QIs to examine/understand quality of care during AS at the population level. A third study aimed to evaluate long-term oncological outcomes at the population level in patients who received initial AS. This thesis establishes a foundation on which to measure and monitor the quality of care for AS patients at the population level. We developed 20 comprehensive structure-process-outcome-based QIs for measuring quality of AS care. Further, by applying these AS QIs to a large Canadian population database, we identified current gaps in the quality of AS care. The findings suggest that process of care QIs measured at PC diagnosis and during eligibility assessment for AS were improving in recent years; however, considerable variation appeared with many process indicators during the AS follow-up phase. Finally, our third study is one of the first to measure long-term oncological outcomes of AS using population-level data compared with initial treatment. Among men diagnosed with low-risk PC and managed with AS, the results suggest excellent 10- and 15-year metastasis-free survival, overall survival, and PC-specific mortality, similar to published observational studies from academic centres. However, at a population level, AS was associated with slightly worse long-term metastasis-free survival, overall survival and PC-specific mortality compared with initial treatment. These results should help clinicians and policy makers understand the impact of AS on long-term outcomes after widespread adoption.