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Interfacial and Mechanical Properties of Hierarchically Reinforced Fiber Thermoplastic Composites
Get PDFThe engineering benefits of fiber-reinforced thermoplastic composite materials have motivated their adoption across numerous industries, but poor fiber-matrix interfacial adhesion limits their mechanical performance. This thesis explores nanoinclusion deposition, a fiber surface modification, as a method to strengthen this interface. A spray coating technique was developed to coat carbon fibers with graphene nanoplatelets (GnPs), and the resulting morphology and fiber-matrix properties were examined against uncoated fibers. Spray coated fibers increased the interfacial shear strength of single-fiber composites made with high-density polyethylene (HDPE) by 155%, significantly exceeding improvements reported in literature despite weak fiber-GnP adhesion. This increase was revealed to be polymer-dependent and related to GnP-induced nucleation leading to transcrystallization. Bulk composites fabricated with spray coated fibers also showed improved mechanical properties, matching or exceeding less scalable deposition techniques. This research establishes nanoinclusion deposition as a scalable strategy to enhance single-fiber and bulk composites, demonstrating substantial potential for advanced manufacturing industries.M.A.S
Mechanistic investigation of the substituent effects on Si–F bond reactivity in phenyl silicon-fluoride acceptors (SiFA)
Get PDFSilicon-fluoride acceptors (SiFA) have emerged as a transformative technology for the development of novel peptide-based PET tracers and theranostic radiopharmaceuticals, offering a rapid, high-yielding, robust, and operationally simple method for incorporating fluorine-18 through isotope exchange on silicon. The di-tert-butylfluoro(phenyl)silane core of SiFA is typically conjugated to biomolecules via a functional group positioned either meta- or para- to the silicon center on the phenyl ring. Although a variety of such substituents have been employed, their impact on the efficiency of 18F-labeling and the hydrolytic stability of the Si–F bond has not been systematically evaluated. In this study, we investigate the electronic effects of commonly used meta and para substituents on the kinetics of these reactions. A Hammett analysis was employed to further elucidate the mechanisms of Si–F bond hydrolysis and to quantify the substituent effect. Furthermore, in light of the growing application of bifunctional SiFAs for incorporation into peptide chains or as linkers between peptides and chelators in radiotheranostics, we synthesized a series of 3,5-disubstituted SiFAs and characterized their physicochemical properties. Our findings provide a foundation for the rational design of novel 18F-labeled radiopharmaceuticals based upon SiFA technology.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Fishing for Millennials? A Present Hope for the Diocese of Niagara
Get PDFAbstract
My full-time ministry began in mid-August,1977 and continued until my retirement on December 31, 2017. Throughout that time, the Anglican Church of Canada was increasingly aware of declining membership, accompanied by a decline in financial resources. It has been suggested that this ongoing decline has begun to define the Anglican Church. “The church as a whole has come to embody the story of how we are not relevant or popular.”
Introducing contemporary liturgy was an abiding interest and a focus of my ministry. I realized that creating a welcoming and inclusive community, increasing lay participation and highlighting children’s ministry were also important aspects of parish life. While the Anglican concern with decline underscored my research, it was not at the centre of it. More important to this dissertation is the question of whether the principles that guided my ministry could contribute to a missional outreach to Millennials, which has become a focus of the Diocese of Niagara.
While many Millennials do not attend church, they admit that they have spiritual needs, and are involved in private prayer and bible reading. In contrast there are some Millennials in the Diocese of Niagara who attend church regularly and participate in the life of their parish. It is these Millennials who are the basis of this dissertation, through a research project that asked them about their personal response to liturgy. In the process, they revealed a considerable amount of data about other aspects of parish life, and suggested some reasons so many in their demographic are disinclined to attend church. Their insights could assist the diocesan evangelistic efforts to reach non-attending Millennials.Doctor of Ministry (DMin
Nonlinear Control Strategies for UAV Navigation in Complex Terrains: A Constraint-Based Approach for Robust Obstacle Avoidance and Mission Efficiency
Get PDFUnmanned Aerial Vehicles (UAVs) have demonstrated significant potential for intelligent transportation systems across various domains, including transportation systems, rescue missions, and environmental monitoring. However, navigating complex terrains necessitates sophisticated control strategies capable of effectively managing dynamic obstacles and environmental uncertainties. This paper employs a constraint-based dynamic control model that integrates the Udwadia-Kalaba method to address nonlinear motion constraints related to path planning and autonomous collision avoidance in navigation transportation systems. A diffeomorphic transformation is utilized to map complex operational requirements laden with constraints into a cohesive framework that incorporates both environmental considerations and mission-specific safety boundaries. To further enhance UAV performance, we introduce constraint following error measure and collision avoidance constraint transformation which facilitate a balanced integration between task-oriented objectives and safety constraints. Additionally, this framework employs robust control techniques to ensure trajectory accuracy under varying initial conditions, thereby improving the adaptability and stability of UAV motion. Simulation results validate that the proposed control design significantly enhances UAV agility and reliability, highlighting its potential for safe, efficient, and robust operation in both complex terrains and navigation transportation systems.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Multi-Spectral and Single-Shot Wavefront Detection Technique Based on Neural Networks
Get PDFConventional wavefront sensors face challenges when detecting frequency-domain information. In this study, we developed a high-precision, and fast multi-spectral wavefront detection technique based on neural networks. Using an etalon and a diffractive optical element for spectral encoding, the measured pulses were spatially dispersed onto the sub-apertures of the Shack-Hartmann wavefront sensor (SHWFS). We employed a neural network model as the decoder to synchronously calculate the multi-spectral wavefront aberrations. Numerical simulation results demonstrate that the average calculation time is 21.38 ms, with a root mean squared (RMS) wavefront residual error of approximately 0.010 μm for 4-wavelength, 21st-order Zernike coefficients. By comparison, the conventional modal-based algorithm achieves an average calculation time of 102.98 ms and wavefront residuals of 0.090 μm. Remarkably, for 10-wavelength analysis, traditional centroid algorithms fail; this approach maintains high simulation accuracy with the RMS wavefront residual error below 0.016 μm. The proposed approach significantly enhances the measurement capabilities of SHWFS in multi-spectral and single-shot wavefront detection, particularly for single-shot spatio-temporal characterization in ultra-intense and ultra-short laser systems
Evaluating the Prognostic Utility of Oral Neutrophil Counts in Periodontitis Patients: a Retrospective Clinical Study
Get PDFOral polymorphonuclear neutrophil (oPMN) levels are potential biomarkers for periodontitis; however, their prognostic utility in terms of periodontitis staging and grading is unknown. Using the gold standard clinical parameter for assessing periodontal inflammation (i.e., bleeding on probing (BOP)), we compared the prognostic utility of oPMN levels against BOP% in terms of differentiating between periodontitis stages II-III and grades B-C. We also studied potential correlations between oPMN level and BOP% with the detection of periodontal pathogens in the gingivocrevicular fluid (GCF). oPMN level was associated with advanced periodontitis stage and grade; where, patients exceeding the computed threshold value of > 1.43 106/mL oPMN suggested stage III and grade C as the appropriate periodontal diagnoses. Significant positive associations were also identified between oPMN level and the detection of pathogenic bacteria. These findings suggest oPMN level may be useful as a multi-purpose risk indicator, both in terms of diagnosing periodontitis and determining the risk for disease progression, but also in recognizing periodontal pockets in which putative species colonize.M.Sc
An Exploration of Equity in Usability Evaluation Methodology
Get PDFThis thesis explores the issue of equity in usability evaluation methods. In human-centred design literature, equity in the evaluation phase has been underexplored. This research problem is examined in two studies. The first study uses failure modes and effects analysis to investigate potential equity risks in the use of usability evaluation methods in healthcare. The second study uses a qualitative survey of usability practitioners to explore how equity is addressed in current usability evaluation practice. The combined results of these studies show that equity in the context of usability evaluations is understood primarily as ensuring samples are representative of intended users. The discussion complicates what representative means for ensuring the usability of designs for all users and charts future research directions for more equitable usability evaluation methods and practice. I argue that situating usability evaluation methodology within a postmodernist paradigm and a reflective practice can be3er orient practitioners toward equity.M.A.S
Sustainable Anode Design for High-Rate and Flexible Lithium-Ion Batteries
Get PDFLithium-ion batteries are a widely used class of rechargeable batteries, commonly employed in everyday applications. Beyond their well-established role as a replacement for traditional internal
combustion engines in the automotive industry, lithium-ion batteries have garnered significant
attention for emerging applications in wearable devices, biomedical equipment, and flexible
electronics. Although widely used, conventional lithium-ion batteries are inherently rigid and
unable to accommodate mechanical deformations such as bending or folding, which are essential
for flexible electronic applications. Beyond structural limitations, they also pose environmental
challenges, as the conventional slurry-casting method for electrode fabrication typically relies on
toxic solvents. To overcome these limitations, this thesis aimed to design flexible, fast charging,
and high-performance anodes while also addressing environmental concerns. The first study
demonstrated the integration of niobium oxide as a fast-charging anode material for lithium-ion
batteries using a sustainable solvent-free electrode processing technique, achieving mechanical
durability and high mass loading, while delivering excellent electrochemical performance even
under high-rate charging and discharging conditions. For the second study,
hydrothermal/solvothermal synthesis were employed to directly grow titanium dioxide on
flexible carbon fiber substrates for the fabrication of a freestanding anode. Given their shared
objectives, both studies highlight environmentally friendly aspects while simultaneously
enabling flexibility and fast-charging capabilities. In summary, this research seeks to contribute
to the advancement of technologies in the expanding rechargeable battery sector.M.A.S
Characterization of the Distinct Activation Mechanisms of BAX and BAK by the Pro-apoptotic BH3-only Protein BIM
No full textApoptosis, a specific form of programmed cell death, enables multicellular organisms to develop and maintain tissue homeostasis by eliminating damaged or harmful cells without provoking an immune response. Apoptosis is tightly regulated in healthy cells and is often dysregulated in various pathologies such as cancer and neurodegenerative diseases. The mechanisms that regulate apoptosis are governed by interactions between pro-apoptotic and anti-apoptotic members of theBcl-2 family proteins, which control the decision-making process for committing cells to death. Execution of this commitment step is done by the pro-apoptotic proteins Bax and Bak, which are the main effectors of the Bcl-2 family that oligomerize and form pores permeabilizing the mitochondrial outer membrane. Bim is another pro-apoptotic member of this family, acting as a potent direct activator of Bax and Bak. Bim binds the monomeric inactive conformations of Bax
and Bak to induce conformational changes that enable homodimerization and eventual multimerization. Cancer cells can evade apoptosis by upregulating the anti-apoptotic Bcl-2 proteins to bind to, thereby inhibiting activated Bax, Bak, and Bim. Alternatively, mutations can occur at crucial binding sites on the pro-apoptotic proteins, disrupting their interactions and
abolishing their cancer-killing functions. Given the role of Bim, Bax, and Bak in tumor suppression, a better understanding of how Bim binds and activates Bax and Bak is needed to improve anticancer therapy. Using a biophysical technique to measure protein-protein interactions, this work identifies a novel binding site on the carboxyl-terminal sequence of Bim (Bim-CTS) that binds Bax and Bak, and is required for Bim to activate Bax and Bak. Measurement of the interaction between Bim and Bax and functional studies to delineate the stepwise activation mechanism of Bax reveal that the Bim-CTS is involved in the early conformational changes of Bax through an interaction with an allosteric ‘trigger-site’ on Bax. Contrasting with the Bax-activating mechanism, the Bim-CTS binds the membrane-binding carboxyl-terminal sequence of
Bak, forming a secondary binding interface that confers functional affinity or avidity for efficient Bak activation. Most importantly, the Bax and Bak-binding functions of the Bim-CTS are separate from the well-known membrane-binding function of this sequence.Ph.D
Integrating PET and MRI Radiomics for Staging and Prognostic Stratification in Anal Canal Cancer
Get PDFAnal canal cancer accounts for approximately 0 [...