VictorJuiz/thesis huggingface dataset:
Development of Novel Hybrid Silica Aerogels with a Reticulated Structure using New Generation of Marcromolecular Precursors

Aerogels (e.g. silica aerogel) have created a prospective market for oil-absorption, insulation and aerospace applications. However, their intrinsic fragility and poor mechanical properties have been a stumbling block to their wider applications. These drawbacks originate from their inherent particulate structure and weak interparticle interactions. For several decades, researchers have been trying to enhance the aerogels’ mechanical properties by improving the particle-to-particle connections. However, the cost was increased processing time, increased density, and increased total thermal conductivity. Therefore, this Ph.D. research aims to find an industrially viable and fast manufacturing technology to produce ultra-light weight and mechanically robust and resilient aerogel while preserving the unique features of the aerogels such as the good thermal insulation properties and high surface area. This dissertation fundamentally addressed the difficulties associated with the improvement of the particle-to-particle connection in the conventional aerogels by inventing a novel non-particulate and reticulate structure, free from the troublesome particles. This new technology relied on the development of a new generation of polymeric silica precursor and a meticulous control of thermodynamics at gelation step. Polymeric precursors with different chemistries and molecular weights were synthesized in the preparatory stage and then through spinodal decomposition, non-particulate and reticulate aerogels were afforded. Thermodynamics variables, molecular weight of the polymeric precursor, solvent, temperature, and the amount of the nonsolvent were systematically studied and correlated to structural parameters and consequently to the final properties. It was found that there is a critical point where a particulate structure transfers to a non-particulate one. The findings have also demonstrated how to tailor the structural factors such as the void fraction, the average pore sizes to optimize the final properties. This study provided an in-depth understanding of processing-structure-property relationship and a novel technology to molecularly engineer the structure and properties of hybrid silica aerogels. Various aerogels’ building blocks assemblies, polymeric precursors, and thermodynamics variables have been investigated to identify the optimal structure and processing methodology to obtain highly robust and super-insulative aerogels.

Keywords: Hybrid Silica Aerogel
Reticulate Structure
Strong
Ultra-insulative
Advisor: Park, Chul B
Spell Checking Nature: Development of a CRISPR- Mediated Gene Editing Approach for the Treatment of Pathogenic Duplications

Duchenne muscular dystrophy (DMD) is a neuromuscular disorder that leads to progressive muscle deterioration, loss of ambulation, and respiratory complications. It is caused by genetic mutations that result in the absence of dystrophin protein expression needed for muscle function. Despite significant advances in our understanding of the pathogenesis of DMD, no curative treatment has been identified to date and the disorder has a life-limiting disease trajectory. Recently, we have pioneered an approach to successfully remove large duplications in patient cells. We first tested this approach in vitro by removing a multi-exon (18-30) duplication of 139 kb in the DMD gene using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated Nuclease (Cas9) with a single guide. To test our treatment approach in vivo, I first generated a mouse model harboring a multiexon duplication of 136.8 kb in Dmd using CRISPR/Cas9. This first multiexon duplication model of DMD specifically mimics a patient duplication of Exons 18-30. Molecular and functional characterization of this model reveals dystrophin deficiency with characteristic markers of dystrophic muscle. Furthermore, using our previously described CRISPR/Cas9 single guide strategy, we have for the first time treated a large genomic duplication in vivo and shown successful removal of the duplication fragment leading to restoration of full-length dystrophin in skeletal and cardiac muscles. Additionally, histopathological analysis shows that treated mice have less indications of dystrophy including fewer centrally localized nuclei as well as significantly improved muscle function. Our findings establish the far-reaching therapeutic utility of CRISPR/Cas9, which can be tailored to target numerous inherited disorders caused by duplications.

Keywords: CRISPR/Cas9
Duchenne muscular dystrophy
Duplication
Gene Editing Therapy
Mouse Model Generation
Structural Variants
Advisor: Cohn, Ronald
Radical Cloud Chemistry: Oxidation of Organic Compounds in Atmospheric Water

Atmospheric aging of organic compounds by photo-chemical oxidation can occur rapidly in the aqueous phase in aerosol particles, cloud droplets, and fog droplets and can result in changes to their chemical composition and absorptivity. Despite their capacity to significantly alter the properties of organic aerosol, aqueous phase reactions have not gained as much attention as other atmospheric aging pathways. The goal of this thesis was to further our understanding of photoreactions of atmospherically-relevant organic compounds in cloud water. This goal was accomplished through three projects, which investigated factors influencing the production of hydroxyl (OH) radicals in aqueous phase reactions and the lifetime, oxidation mechanism, and fate of light absorbing molecules that contribute to brown carbon. In the first project, the impact of dissolved organic compounds, specifically from α-pinene ozonolysis secondary organic aerosol (SOA) material, on the Fenton reaction, a major source of OH radicals in cloud and fog water, was investigated. OH radical production was significantly suppressed in the presence of SOA material, likely due to complexation of the iron involved in the Fenton reaction. In the second project, aqueous photo-oxidation kinetics of three light-absorbing nitrophenol compounds often associated with wildfire smoke were examined and were found to have an in-cloud lifetime on the order of hours. Photo-oxidation initially caused an absorption enhancement that corresponded to products with added oxygenated functional groups. Further photo-oxidation led to products that do not absorb visible light, reducing their contribution to atmospheric warming. In the third project, representative and chemically complex brown carbon was generated in the laboratory from wood smoke. Light absorption increased from aqueous photoreaction and OH oxidation and was linked to oligomerization and functionalization of aromatic compounds, similar to the nitrophenol chemistry. While extended OH oxidation led to a decrease in absorbance, brown carbon in wood smoke is likely to have a longer lifetime than estimated by individual components. Overall, this work demonstrated key outcomes of organic chemical transformations resulting from aqueous atmospheric aging under relevant cloud conditions and provided implications for their effect on the climate system.

Keywords: atmospheric chemistry
Advisor: Abbatt, Jonathan
Development of Surface-modified Electrodes for Electrochemical Energy Storage Applications

Recent commercialization efforts made in the fields of flexible sensors, low-energy Bluetooth transmitters, and low-power thin-film electronics have contributed to significant fast-paced growth in the smart wearable industry. This drastic paradigm shift in the flexible electronics component design has fuelled an evolution in the flexible personal electronics, biomedical, athletics, and logistics industries as more flexible, thin-film products are offered. Flexible thin-film electrochemical capacitors (EC) or supercapacitors are energy storage solutions that offer both high energy and power densities resulting from the exceptional high electrode specific surface area and appropriately tuned electrode/electrolyte interface. To meet both the electrochemical and mechanical requirements, several aspects of the electrode design was to be considered in the proposed flexible EC devices: a) Areal- and gravimetric specific capacitance; b) Charge-discharge cycling properties; c) Mechanical bending and flexing behaviours; and d) Environmental stability. In this work, novel facile techniques in fabricating flexible EC electrodes with micro- and nano-structured surface modification have been proposed to produce high-performing flexible EC electrodes with additional intrinsic multi-functionalities, such as piezoresistive sensors and breathing sensors, along with energy storage. Herein, to create facile pathways for fabricating flexible, high-performance EC electrodes, this thesis has been divided into the following studies: The first study focuses on the design of a novel environmental-controlled self-assembly method, where polyaniline (PAni) nanorod structures were grown on polyacrylonitrile (PAN) nanofibers for high-surface-area textile electrochemical capacitor electrodes with intrinsic piezoresistive tactile sensing capabilities. The second study relied on a novel laser-assisted photochemical reduction method to produce reduced graphene oxide micro-ribbon textile electrode directly on a liquid surface, which can be transfer printed onto any substrate for both supercapacitors and breath sensor applications. The third study validated a method for creating hierarchically structured multilayer reduced graphene oxide for flexible intercalated supercapacitor electrodes where simultaneous reduction and nitrogen-doping were successfully achieved. The last study explored the possibility of creating a multi-layered flexible polypyrrole micro-foam/carbon nanotube composite electrodes for flexible supercapacitor devices via the creation of three-dimensional polypyrrole microsphere architecture.

Keywords: Flexible Energy Storage
Multi-functional Devices
Nanostructuring
Smart Textiles
Supercapacitors
Surface Modifications
Advisor: Naguib, Hani E
Hybrid Carbon-modified Polymer-based Silica Aerogels with Low Thermal Conductivity and Improved Mechanical Properties

Recently, graphene nanoplatelets (GnPs) have attracted a great deal of attention as a multifunctional reinforcing nanofiller in polymer composites, which is due to their unique two-dimensional layer structure with honeycomb characteristics, their excellent mechanical properties and their isotropic reinforcement capability in more than one direction. Here, the effect of the spinodal decomposition process in creating a nonparticulate morphology in the GnPs' orientation and dispersion is investigated. It is also studied how the gelation reaction can participate in the inclusion of GnPs in the aerogel backbone during the sol-gel process to strengthen the body of the gel. Meanwhile, the process of GnP exfoliation and restacking elimination during sol-gel transition is comprehensively studied. The present thesis also analyzes the gelation kinetics and thermodynamics in the presence of GnP and graphene oxide (GO) using in-situ rheology, light scattering (DLS), small-angle X-ray scattering (SAXS) and pore-structure-analyzer. The data collected during the gel network formation obtained with and without GnP or GO are analyzed in which to fully study the kinetics of structure evolution during the gelation. It is confirmed that the use of spinodal decomposition to create a nonparticulate gel network helps to offset the required long aging step during the sol-gel process, which is inevitable to strengthen the particle-to-particle neck using conventional methods such as nucleation and growth. It is also verified that this gelation technique enables the system to take advantage of GnP's full potential through correct exfoliation and elimination of restacking and re-agglomeration. The carbon-modified polymeric silica-based aerogels were first modified to enhance their mechanical properties by the addition of flexible nanofibers and stiff nanosheets into the structurer. The composites assembled homogeneously into the carbon-modified polymeric silica-based aerogel structure to create a uniform network of the solid struts along with the backbone. With such a network, the mechanical properties of the aerogels increased dramatically while preserving/advancing their unique features such as high surface area and thermal stability. The new aerogels could operate a high temperature with a high surface area. Furthermore, such material could resist moisture, which makes this material ideal to be used in high temperatures and humid environments.

Keywords: Bimodal porosity
Graphene nanoplatelets
Mechanical
Silica aerogel
Spinodal decomposition
Thermal conductivity
Advisor: Park, Chul B
Naguib, Hani E
Facilitating Pathways Out of Crime: The Role of Strengths in Risk Assessment and Rehabilitation among Justice-Involved Youth

This dissertation consists of two papers examining the role of strengths in the youth justice context. Paper 1 examined the psychometric properties of a strengths measure, the Structured Assessment of Protective Factors for Violence Risk – Youth Version (SAPROF-YV). In a sample of 305 youth, exploratory factor analysis suggested the removal of four items and the resulting revised scale demonstrated good internal consistency and strong convergent validity. There was additionally evidence for a promotive effect, with the total score inversely predicting reoffending in the 3-year follow-up period. Strength factors did not provide incremental predictive validity over risk factors. A significant moderation effect revealed that strengths are protective among lower risk youths but amplify the impact of risk on recidivism among higher risk youths. Paper 2 focused on the relationship between strengths and service provision and sought to evaluate whether strengths function as specific responsivity factors as proposed by the Risk-Need- Responsivity model. Findings from a sample of 261 youth indicated that as the proportion of identified criminogenic needs met via probation-provided and -coordinated services increased, youths’ odds of reoffending decreased, for both males and females. Importantly, having more identified strengths was associated with having a higher proportion of criminogenic needs addressed during probation, lending some support to the hypothesis that strengths function as specific responsivity factors; the relationship between service-to-needs matching and reoffending was not moderated by strengths. These studies provide preliminary support for the validity and reliability of the SAPROF-YV. Given the controversial moderation findings, the use of the SAPROF-YV for enhancing recidivism risk prediction is not currently recommended; however, the findings do suggest that youth strength profiles are associated with the quality and quantity of services received over the course of probation and further research into how strengths can guide and improve services for justice-involved youth is warranted.

Keywords: Forensic psychology
Rehabilitation
Risk Assessment
Risk-Need-Responsivity
Strengths
Advisor: Peterson-Badali, Michele
Skilling, Tracey
EvacuSafe: A Smart Evacuation Management System for Buildings

Tall buildings and their occupants are highly sensitive to emergencies. Decision-making in these situations is complicated due to high population densities residing in these dwellings, complexity of emergency management strategies, significance of quick response in these cases, and unknown reactions of occupants under stress. This research develops an evacuation management system (EMS), named EvacuSafe, to support decision-making and crowd handling during evacuations. EvacuSafe supports a fully automated process of detecting the fire, simulating the growth pattern of the hazard, generating multiple strategies of evacuation, evaluating the strategies based on the risk to evacuees, and finally guiding evacuees along their egress route. EvacuSafe’s architecture consists of the three main modules of fire dynamics simulation, agent-based crowd simulation, and graph search path-planning. EvacuSafe is model-centric, and the entire data storage and data transfer between its three modules are based on Building Information Modelling (BIM) and Industry Foundation Classes (IFC). By integrating BIM, agent-based crowd simulation, and fire simulation, EvacuSafe enables a performance-based evaluation of building evacuations for different building designs. In real-time mode, EvacuSafe converts BIM to a Geometric Network Graph (GNG) and performs path-planning and guidance during emergencies. In addition, the guidance system in EvacuSafe is based on the application of Adaptive Dynamic Signage System (ADSS). This research aims for a smart emergency management system that will be less restricted by human factors and more efficient in saving the lives of occupants in emergencies.

Keywords: BIM
Building
Evacuation
Fire Dynamics Simulation
IFC
Path Planning
Advisor: McCabe, Brenda
The World Bank and Inclusive Policymaking Practices [1980-2014]. A Theory of Change and Stability Through Collective Learning

This dissertation presents a theory of change and stability of the World Bank based on collective learning processes and communities of practice. It is broadly divided into two parts. First, I aim to demonstrate how the Bank changed its policymaking practices between 1980 and 2014 in terms of [1] consultation with NGOs, [2] participation of citizens in design and implementation of projects, and [3] ownership by borrowing governments. This change, I argue, is due to three processes of collective learning: the interactions at the boundaries of communities of practice; and the constant contestation of practices. In the second part of the dissertation, I argue that in the end, this evolution of practice reinforced the Bank technocratic and neoliberal political rationality, thus promoting overall stability in its modus operandi. Building on French philosophers Pierre Dardot and Christian Laval, I seek to explain how change in an international organization (even if meaningful in many ways) can promote stability in its employees’ political rationality. Methodologically, this dissertation is based on a historical process-tracing of the period 1980-2014, using 41 first-hand interpretive interviews with World Bank employees and officials, 80 open source in-depth interviews with senior Bank managers, as well as an archive analysis.

Keywords: International Development
International Organisations
Learning
Practices
Social Theory
World Bank
Advisor: Adler, Emanuel
Towards Overcoming Limitations on MRI-guided Focused Ultrasound Hyperthermia-mediated Drug Delivery using Thermosensitive Liposomes

Magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) hyperthermia is a completely non-invasive thermal procedure that involves slightly heating up a localised region of the body to between 41°C and 45°C. MRgFUS hyperthermia can trigger the local release of chemotherapy from thermosensitive liposomal drug carriers in high concentrations within heated tumours. These temperature elevations have synergistic effects with chemotherapy and radiotherapy when maintained for tens of minutes up to several hours. Presently, limitations including bone shielding, respiratory motion and large blood vessel cooling make heating of many anatomical locations difficult to maintain for long durations. These limitations prevent MRgFUS hyperthermia from being achieved in the kidney, liver or the head and neck. By developing new treatment strategies and sophisticated MRI-compatible FUS delivery systems that can overcome these limitations, MRgFUS hyperthermia with thermosensitive liposomal chemotherapy can be used to treat a more broad spectrum of tumour types. This thesis describes standalone FUS and microbubble-mediated strategies to overcome the limitations of MRgFUS hyperthermia. First, the incorporation of contrast agent microbubbles was investigated with MRgFUS hyperthermia in rabbit thigh muscle and experimental rabbit Vx2 tumours to reduce the applied power to maintain the temperature elevation. Second, a FUS hyperthermia system compatible with in vivo two-photon microscopy was developed as a platform for studies of controlled hyperthermia and drug delivery in mouse tumours. Practically simple short duration (~30s) temperature elevations to 42°C were shown to release substantial amounts of chemotherapy doxorubicin from thermosensitive liposomes. Third, the therapeutic efficacy of short duration temperature elevations to 42°C was evaluated in rabbit thigh Vx2 tumours. Considerable tumour growth inhibition and survival prolongation was observed with the short duration heating approach, demonstrating the potential for overcoming limitations on clinical MRgFUS hyperthermia with thermosensitive liposomal chemotherapy. The results of this thesis demonstrate that through the incorporation of microbubbles, as well as short duration heating strategies, the practical limitations of clinical MRgFUS hyperthermia can be alleviated. The clinical investigation of these heating strategies is warranted in order to provide cancer patients with a non-invasive treatment option that can both improve their response to therapy and reduce treatment-associated side effects.

Keywords: cancer therapy
doxorubicin
focused ultrasound
hyperthermia
microbubbles
MRI thermometry
Advisor: Goertz, David E
Hynynen, Kullervo
Governance of Child Health Policy: The Canadian Context for Developmental Screening

Child health policymaking is complex, necessitating collaboration among various sectors and actors. This is particularly evident in “developmental screening.” The potential to routinely assess development in early childhood— to ‘screen’ for developmental problems— holds a potent if contested promise to optimize child health. Clinical evidence supporting systematic population-level interventions is insufficient, yet many health-professional associations have endorsed the practice and several developmental-screening initiatives have been implemented internationally, including in Ontario— the only Canadian province to implement developmental screening (the Enhanced Well-Baby Visit). The controversies surrounding developmental screening suggests that the ‘problem’ is not solely technical: it reflects political contests over the intervention’s aims, the justifications that warrant action, and the arrangements of actors who debate and authorize policy change. In brief, it reflects the policy challenges of agenda-setting and governance. This research describes approaches to the governance of child health, and explores relationships between governance arrangements and decision-making, particularly the impacts on agenda-setting and evidence use. Using a comparative case study design involving interpretive qualitative methods, I analyzed policy documents and conducted interviews (n=40) with child-health policy experts in Ontario and Manitoba. I found jurisdictional differences in policy attention and governance, specifically in the structure of institutions, the organization of interests, and the ideas of stakeholders as they apply to screening programs. The study reveals how framing impacts agenda-setting and how governance arrangements influence the design and delivery of policy. Presented as three manuscripts, key findings include: (1) developmental screening is framed, and understood, as three distinct agendas (medical, social, political) for child health; (2) comparing Manitoba and Ontario’s efforts for ‘joined-up’ governance reveals that perceptions of policy success depends on whether collaboration or action is prioritized; and (3) Ontario’s implementation experience for the 18-mos visit illustrates that the choice of primary care as the venue for delivery shapes how interventions are defined and delivered. Overall, this work highlights the complexity of child health policy, illuminates challenges in screening for social risk, and contributes to current debates about how professionals intervene in early child health.

Keywords: Child health
Governance
Health policy
Population health
Screening
Advisor: Miller, Fiona A