Physical Sciences and Mathematics Commons^™

P-T-X Constraints On Ilmenite Unit Cell And Relationship To Kimberlitic And Non-Kimberlitic Sources, Mitchell R. Galarneau

Electronic Thesis and Dissertation Repository

This research investigates the mineral ilmenite, focusing on the relationship between crystal structure and geochemical and/or pressure data. Ilmenites were obtained from diamond-rich and diamond-poor kimberlites and non-kimberlitic localities, to discriminate between these populations. Crystallographic results showed a delineation between kimberlitic and non-kimberlitic ilmenites at a c-axis value of 14.02 (±0.01) Å. Adding geochemistry and pressure enhances the separation of kimberlitic and non-kimberlitic samples; however, this isn’t the case for diamond-rich versus diamond-poor kimberlites, even with three-dimensional and cluster analyses. A subset of kimberlitic ilmenites (manganese rich) were found with c-axis values and geochemical concentrations similar to non-kimberlitic ilmenites.

By …

High Resolution Ion Beam Investigations Of The Mechanisms Of Titanium Anodization, Mitchell A. Brocklebank

Electronic Thesis and Dissertation Repository

The unique behaviour of thin films, and their surfaces and interfaces, significantly impact material and device properties. Probing these structures with ion beams (IB) provides quantitative composition and thicknesses measurements. In this dissertation, the IB techniques of medium energy ion scattering (MEIS), nuclear reaction profiling (NRP) and Rutherford backscattering spectrometry (RBS) are used to analyze energy losses in ultra-thin films, as well as elucidate the mechanisms of anodic film growth.

Accurate stopping cross sections of protons, ε, in the medium energy range (50-170 kV) often show deviations from Bragg’s rule. Here, ε_Ti, ε_Si, and ε_{TiO2 …}

Near-Earth Asteroid Resources: Review And Analogue Study Of Highly Siderophile Elements In Main-Group Pallasites, Liam R. J. Innis

Electronic Thesis and Dissertation Repository

The potential for NEAs as targets for space resource utilization has been explored. Water and PGEs have been identified as resources with potential profitability in existing markets. Of the ~18,000 asteroids in the known NEA catalogue, seven and three are expected to be prospective for water and PGEs when accounting for size, resource concentration, and accessibility. Improved NEA discovery campaigns, with emphasis on spectroscopy, and advancements in space transportation and autonomous robotic technology are crucial to future success of NEA resource utilization. LA-ICP-MS was used to evaluate main-group pallasites (PMG) for PGE potential. Bulk metal concentrations of most PGEs are …

A Targeted Investigation Of The Upper Contact Unit Of The Sudbury Igneous Complex In The North Range, Sudbury Impact Structure, Canada, Lindsay E. Debono

Electronic Thesis and Dissertation Repository

The Sudbury Igneous Complex (SIC) represents the remnant of a crystalline impact melt sheet of the Sudbury impact structure; and is historically and presently a strategic exploration target sustaining the region's prolific mining camp. In order to better understand the SIC, it is critical to investigate the chilled upper contact of the SIC, which has historically received little recognition. Through field observations, whole rock geochemistry, petrography, and electron microprobe analysis, this study concludes that the SIC upper contact is in fact extensive across the North Range of the SIC. Additionally, the geochemistry of the SIC units, offset dykes, and upper …

Selected Topics In Quantization And Renormalization Of Gauge Fields, Chenguang Zhao

Electronic Thesis and Dissertation Repository

My thesis covers several topics in the quantization and renormalization of gauge fields, ranging from the application of Dirac constraint procedure on the light front, to the manipulation of Faddeev-Popov method to enable use of the transverse-traceless gauge in first order gravity. Last, I study renormalization group ambiguities and carry out a new characterization method for models with one, two and five couplings.

In chapter 2 we apply the Dirac constraint procedure to the quantization of gauge theories on the light front. The light cone gauge is used in conjunction with the first class constraints that arise and the resulting …

Statistical Tools For Assessment Of Spatial Properties Of Mutations Observed Under The Microarray Platform, Bin Luo

Electronic Thesis and Dissertation Repository

Mutations are alterations of the DNA nucleotide sequence of the genome. Analyses of spatial properties of mutations are critical for understanding certain mutational mechanisms relevant to genetic disease, diversity, and evolution. The studies in this thesis focus on two types of mutations: point mutations, i.e., single nucleotide polymorphism (SNP) genotype differences, and mutations in segments, i.e., copy number variations (CNVs). The microarray platform, such as the Mouse Diversity Genotyping Array (MDGA), detects these mutations genome-wide with lower cost compared to whole genome sequencing, and thus is considered for suitability as a screening tool for large populations. Yet it provides observation …

Layer-By-Layer Construction Strategies Towards Efficient Czts Solar Cells, Matthew J. Turnbull

Electronic Thesis and Dissertation Repository

Solar energy has very high potential for ensuring the world’s energy requirements for the long-term future. Earth-abundant materials like Cu₂ZnSnS₄ (CZTS) are especially desirable, with a non-toxic, low-cost nature, though the quaternary nature allows for a lot of crystal structure variability, and thus underwhelming performance. This Ph.D. thesis is devoted to deepening the understanding of the CZTS material formation, and the processes that can be used to control it, to construct a low-cost, high efficiency CZTS-based solar cell. The layer-by-layer approach presented within this thesis shows great potential for rectifying the problem. CZTS nanocrystal (NC) stoichiometric control …

Experimental Measurements Of Human Cough Airflows From Healthy Subjects And Those Infected With Respiratory Viruses, Nicholas Dudalski

Electronic Thesis and Dissertation Repository

Research concerning person-to-person respiratory virus transmission is required to develop reliable, evidence-based infection prevention and control measures. Experimental studies of human coughs were comprehensively critiqued from the point of view of methodologies, aerodynamics, droplet dispersion and virology. Particle image velocimetry (PIV) and hot-wire anemometry (HWA) measurements were conducted at x=1 m away from the mouth of human subjects to develop a model for cough flow behaviour at greater distances from the mouth than those studied previously. Experiments were conducted for sick subjects who had presented with influenza-like illness, together with a cohort of healthy subjects. Biological aerosol sampling was conducted …

Coupling Scanning Electrochemical Microscopy And 3d Modelling To Probe Membrane Permeability Of Human Bladder Cancer (T24) Cells, Fraser Filice

Electronic Thesis and Dissertation Repository

Scanning electrochemical microscopy (SECM) scans a biased ultramicroelectrode (≤ 25 µm) probe over a sample to characterize topography, physical properties and chemical reactivity. In this dissertation, SECM was used to investigate the metal-induced changes in membrane response of single live human bladder cancer cells (T24). SECM imaging was coupled to 3D finite element method (FEM) simulations which were the first of their kind, providing advanced quantification of sample traits under conditions not previously usable.

The effects of Cd²⁺ on T24 cell membrane permeability were examined. Experimental depth-scan imaging was coupled with full 3D FEM simulations, eliminating many limitations of …

Hydrogen-Deuterium Exchange Mass Spectrometry And Molecular Dynamics Simulations For Studying Protein Structure And Dynamics, Yiming Xiao

Electronic Thesis and Dissertation Repository

Deciphering properties of proteins are essential for human health and aiding in the development of new pharmaceuticals. This dissertation uses hydrogen-deuterium exchange (HDX) mass spectrometry (MS) and molecular dynamics (MD) simulations to study protein dynamics, for improving the understanding of protein folding/unfolding mechanisms, and ligand binding and allosteric regulation.

Chapter 2 uses HDX-MS for probing the conformational dynamics of myoglobin in the presence of N₂ bubbles. We propose a dynamic model that reproduces the observed data: “semi-unfolded” “native” “globally unfolded” -> “aggregated”. Chapter 3 focuses on osteoprotegerin (OPG), which hinders bone resorption by inhibiting RANK/RANKL interactions. The dimerization of …

Mechanism Of Protein Charging And Supercharging In Electrospray Ionization: Molecular Dynamics Simulations And Experimental Investigations, Haidy S. Metwally

Electronic Thesis and Dissertation Repository

Electrospray ionization mass spectrometry (ESI-MS) is a powerful technique for investigating protein structures, conformations, and interactions. Despite its widespread use, many fundamental aspects of ESI remain poorly understood. In this thesis, we use a combination of molecular dynamics (MD) simulations and experiments to gain insights into the hidden complexities of ESI-MS.

Chapter 2 discusses the topic of salt-induced protein signal degradation. Salts such as NaCl, CsCl, and tetrabutyl ammonium chloride (NBu₄Cl) interfere with MS data acquisition, leading to adduct formation and signal suppression. MD simulations provide an explanation for these salt interferences. Signal suppression can be broken down …

Probing Trapped Extracellular Vesicles By Surface-Enhanced Raman Spectroscopy, Lauren Kaufman

Electronic Thesis and Dissertation Repository

Extracellular vesicles (EVs) are released by nearly all cell types within the human body and have been found to play important biological roles including cell-to-cell communication, apoptosis and tissue repair. Lacking cellular machinery, these nano-sized vesicles carry functional proteins and nucleic acids from their parent cells, providing insight into biomarkers present in healthy, cancerous and diseased cells. EVs may be isolated from biofluids such as from blood or urine. Their detection and characterization holds extreme potential in developing less invasive disease detection and treatment methods.

In this work, we propose use of lithographic techniques to fabricate platforms to allow for …

Mapping Debris Disks At Extreme Contrast: Near-Ir Polarimetric Differential Imaging With The Gemini Planet Imager., Juan Sebastian Bruzzone

Electronic Thesis and Dissertation Repository

Debris disks are gas-poor evolved circumstellar disks that show decreased near- to mid- infrared thermal excess emission because of lack of material close to the star. Regarded as massive analogues to the Main Asteroid or Kuiper Belts in the Solar System, these often young dust-rich disks comprise second-generation dust created by disruptive collisions of planetesimals and the decay products of asteroids and comets. Of the dozen or so directly imaged planets to date many share a distinctive characteristic: they reside in stellar systems known to also possess circumstellar dust. High-angular resolution characterization of debris disks, whose morphology is thought to …

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging Of Zp1609 And Amyloid Beta, Jasmine S. H. Wang

Electronic Thesis and Dissertation Repository

The revolutionary development of soft ionization techniques like matrix-assisted laser desorption/ionization (MALDI) has opened up the possibilities for mass spectrometry (MS) in protein detection, identification, and sequencing. The ability of MALDI MS to acquire images of intact tissue sections offer an additional dimension of analysis where location information can be attained. Visualization of biological systems help to unravel the complexities of cells, drug pathways, and disease pathology. However, the capabilities of MALDI MS imaging are often being questioned, as signals are typically biased towards the most abundant component within a complex sample. Within biological tissue samples, the most abundant components …

Synthesis And Characterization Of Alkynyl-Substituted Boron Formazanate Dyes, Alex Van Belois

Electronic Thesis and Dissertation Repository

This thesis outlines the synthesis and characterization of the first alkynyl-substituted boron formazanate complexes and explores the electronic and structural changes that occur in these systems as a result of chemical modification at the boron centre. An alkynyl-substituted complex appended with a redox-active handle is also described, and the chemical reduction and oxidation of this system is explored. Finally, a model reaction is examined as a proof of concept toward the post-synthetic modification of these boron formazanate systems through copper(I)-assisted alkyne-azide cycloaddition chemistry. Exploiting chemistry at the boron centre opens up new possibilities toward incorporating function onto the boron formazanate …

Statistical Modeling Of Co2 Flux Data, Fang He

Electronic Thesis and Dissertation Repository

Carbon dioxide (CO2) flux is important for agriculture and carbon cycle studies. Only a small proportion of the land is currently covered by proper equipment to directly collect CO2 flux data. The CO2 flux data has an obvious annual cycle with the phase changing from year to year. How to build a model to estimate the annual effect and seasonal dynamics is a challenging task. With the help of the Moderate Resolution Imaging Spectroradiometer (MODIS) which is carried by NASA satellites, corresponding data, such as normalized difference vegetation index (NDVI), is freely available from NASA. Our goals are modeling the …

The Periglacial Landscape Of Mars: Insight Into The 'Decameter-Scale Rimmed Depressions' In Utopia Planitia, Arya Bina

Electronic Thesis and Dissertation Repository

Currently, Mars appears to be in a ‘frozen’ and ‘dry’ state, with the clear majority of the planet’s surface maintaining year-round sub-zero temperatures. However, the discovery of features consistent with landforms found in periglacial environments on Earth, suggests a climate history for Mars that may have involved freeze and thaw cycles. Such landforms include hummocky, polygonised, scalloped, and pitted terrains, as well as ice-rich deposits and gullies, along the mid- to high-latitude bands, typically with no lower than 20o N/S. The detection of near-surface and surface ice via the Phoenix lander, excavation of ice via recent impact cratering activity as …

Exploring The Chemistry Of Asymmetric Phosphines & Phosphinidene Sulfides, Taylor E. Pritchard

Electronic Thesis and Dissertation Repository

The field of low-coordinate main group chemistry has seen huge development in the last 30 years, with novel compounds that demonstrate unique structures and reactivity. Isolation of these species has relied on thoughtfully designed substituents normally containing substructure steric bulk. The area of phosphinidene chalcogenide isolation and transfer remains poorly understood by comparison. In this context, the major focus of thesis was on the development of a room-temperature method for the transfer of RP=S moieties with and without sterically demanding substituents. The preparation and complete characterization of new asymmetric phosphines with m-terphenyl ligands was also reported. In Chapter 2, …

Investigation Of Chaos In Biological Systems, Navaneeth Mohan

Electronic Thesis and Dissertation Repository

Chaos is the seemingly irregular behavior arising from a deterministic system. Chaos is observed in many real-world systems. Edward Lorenz’s seminal discovery of chaotic behavior in a weather model has prompted researchers to develop tools that distinguish chaos from non-chaotic behavior. In the first chapter of this thesis, I survey the tools for detecting chaos namely, Poincaré maps, Lyapunov exponents, surrogate data analysis, recurrence plots and correlation integral plots. In chapter two, I investigate blood pressure fluctuations for chaotic signatures. Though my analysis reveals interesting evidence in support of chaos, the utility such an analysis lies in a different direction …

Allostratigraphy Of The Viking And Joli Fou Formations, The Lower Colorado Group (Upper Albian), Central Alberta And Saskatchewan, Western Canada Foreland Basin, Matea Drljepan

Electronic Thesis and Dissertation Repository

Strata of the Late Albian Lower Colorado Group are widely distributed in subsurface and outcrop in the Western Canada Foreland Basin. The rocks represent depositional environments ranging from alluvial to offshore marine. The Lower Colorado Group comprises, in ascending stratigraphic order, the Joli Fou, Viking, Westgate, and Fish Scales formations. Mudrocks of the Joli Fou Formation record a time when the interior of North America was flooded by a shallow sea that led to the connection of the Polar Ocean and the Gulf of Mexico. Ensuing sea-level fall and regression led to deposition of Viking Formation sandstone across much of …

Performance Impact Of Different Lower-Limb Setup Positions In The Backstroke Swimming Start, Gordon E. Barkwell

Electronic Thesis and Dissertation Repository

The performance impact of different knee extension angles in the setup position for a backstroke start was evaluated using an instrumented starting surface. Ten backstroke swimmers completed maximum-effort starts in each of two setup positions: one with the knees flexed, and one with the knees extended. The start handles and touchpad were instrumented with tri-axial force plates. Activity of major hip and knee extensors was measured using surface electromyography. Body position was recorded throughout the start using two high-speed cameras. There was no difference in time to 10 m between the two conditions, indicating there is likely no advantage in …

High Performance Sparse Multivariate Polynomials: Fundamental Data Structures And Algorithms, Alex Brandt

Electronic Thesis and Dissertation Repository

Polynomials may be represented sparsely in an effort to conserve memory usage and provide a succinct and natural representation. Moreover, polynomials which are themselves sparse – have very few non-zero terms – will have wasted memory and computation time if represented, and operated on, densely. This waste is exacerbated as the number of variables increases. We provide practical implementations of sparse multivariate data structures focused on data locality and cache complexity. We look to develop high-performance algorithms and implementations of fundamental polynomial operations, using these sparse data structures, such as arithmetic (addition, subtraction, multiplication, and division) and interpolation. We revisit …

Topological Recursion And Random Finite Noncommutative Geometries, Shahab Azarfar

Electronic Thesis and Dissertation Repository

In this thesis, we investigate a model for quantum gravity on finite noncommutative spaces using the topological recursion method originated from random matrix theory. More precisely, we consider a particular type of finite noncommutative geometries, in the sense of Connes, called spectral triples of type ${(1,0)} \,$, introduced by Barrett. A random spectral triple of type ${(1,0)}$ has a fixed fermion space, and the moduli space of its Dirac operator ${D=\{ H , \cdot \} \, ,}$ ${H \in {\mathcal{H}_N}}$, encoding all the possible geometries over the fermion space, is the space of Hermitian matrices ${\mathcal{H}_N}$. A distribution of the …

Vibrating-Wire Rheometry, Cameron C. Hopkins

Electronic Thesis and Dissertation Repository

This thesis consists of two projects on the behaviour of a novel vibrating-wire rheometer and a third project studying the gelation dynamics of aqueous solutions of Pluronic F127. In the first study, we use COMSOL to perform two-dimensional simulations of the oscillations of a wire in Newtonian and shear-thinning fluids. Our results show that the resonant behaviour of the wire agrees well with the theory of a wire vibrating in Newtonian fluids. In shear-thinning fluids, we find resonant behaviour similar to that in Newtonian fluids. In addition, we find that the shear-rate and viscosity in the fluid vary significantly in …

Plant Stimuli-Responsive Biodegradable Polymers For The Use In Timed Release Fertilizer Coatings, Spencer Heuchan

Electronic Thesis and Dissertation Repository

The use of nitrogen-based fertilizers continues to accelerate with human population growth and increases in global food requirements. Enhanced efficiency fertilizers (EEFs) have been developed to improve the synchronization between nutrient supply and crop nutrient demand. However, many of the current controlled release fertilizers are coated with non-degradable polymers that contribute to accumulation of microplastics within ecosystems. This thesis describes research towards the development of a new class of fertilizer coatings using a self-immolative polymer known as poly (ethyl glyoxylate) (PEtG). PEtG itself does not have suitable properties to produce a viable coating but once blended with another degradable polyester …

Quantifying Temperatures In The Early Solar Nebula And On Parent Bodies Using Cation Ordering In Spinel From Cais In Carbonaceous Chondrites, Victoria Houde

Electronic Thesis and Dissertation Repository

Understanding the early solar system requires studying early-formed materials. Calcium-Aluminium-Rich Inclusions (CAIs) are the oldest materials in the solar system. Spinel (MgAl₂O₄) is common in CAIs. Its cation distribution relates to formation, or most recent equilibration, temperature. This can be measured using ²⁷Al Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR) spectroscopy. Calibration curves can be used to calculate temperature.

Micro X-ray Diffraction identified spinel-containing CAIs in four of seven meteorites tested. ²⁷Al MAS NMR and ²⁷Al Triple Quantum (3Q) MAS NMR was acquired at 21.1 Tesla. Temperature estimates were calculated for each …

Design, Synthesis, And Evaluation Of Novel Protease-Activated Receptor 2 (Par2)-Targeting Imaging Agents For Cancer, Jordan C. Lesarge

Electronic Thesis and Dissertation Repository

Aberrant function and over-expression of protease-activated receptor 2 (PAR2), a GPCR, is associated with various cancers and inflammatory diseases. PAR2-targeting ligands have been developed with therapeutic applications but the development of imaging probes is lacking. A series of PAR2-targeted fluorescent and ¹⁸F-PET imaging agents were synthesized and assessed for PAR2-binding. A novel dye-conjugated peptide, Isox-Cha-Chg-ARK(Sulfo-Cy5)-NH₂ (EC₅₀=16nM, K_D=38nM), showed >10-fold increase in potency and binding affinity for PAR2 compared to the leading known fluorescent probe. A novel PET imaging ¹⁸F-labeled peptide, Isox-Cha-Chg-AR-Dpr([¹⁸F]4-FB)-NH₂, is the first PAR2-targeted in vivo imaging agent. …

Ureilite Meteorite Record Of Shock Metamorphism And Parent Body Processes, Yaozhu Li

Electronic Thesis and Dissertation Repository

Ureilites are an abundant non-chondritic meteorite class that are petrographically similar to terrestrial ultramafic rocks, consisting mostly of coarse-grained olivine and pyroxene, with remarkably low occurrence of plagioclase feldspar. This work examines a suite of ureilites (six monomict ureilites and one polymict ureilite), primarily focusing on the mineral olivine as a recorder of shock damage. Optical petrography and Raman spectroscopy provide context information, and in-situmicro-X-ray diffraction (𝜇XRD) is used to obtain quantitative measurements of diffraction peak Full-Width-Half Maxima upon integration along the chi direction on 2D XRD patterns. Ureilites show an increasing streak length of FWHMχ and asterism (discrete …

The Development Of Metal Complexes As Components Of Fluorescent And Nuclear Imaging Probes, William Turnbull

Electronic Thesis and Dissertation Repository

The advent of molecular imaging as a discipline has drastically improved our ability to understand the biochemical and cellular events that drive life, death and disease. This thesis will document the discovery of new metal chelators for Re/^99mTc, new methods of incorporating these metals into peptide structures, as well as new fluorescent compounds. These novel methods and compounds may be used in the development of molecular imaging probes for single photon emission computed tomography (SPECT) and optical imaging techniques, with applications for differentiating cancerous tissue from benign and healthy.

Chapter 2 discusses the development of a dual modality …

Investigating Non-Targeted Screening And Accurate Quantitation Of Trace Surface Water Contaminants Using High-Resolution Mass Spectrometry, Lucas M. Morrison

Electronic Thesis and Dissertation Repository

The human impact on surface water is a growing concern and the chemical surveying of contaminants including pharmaceuticals and pesticides is currently lacking. Neonicotinoids in particular, are among the most widely used insecticides that have prompted environmental concern and require monitoring. Chemical contaminants in environmental water samples are commonly analyzed by targeted tandem mass spectrometry. However, this requires a prior knowledge of the contaminants in the area of interest. Here, surface water samples were screened by utilizing optimized data-independent acquisition (DIA) methods and the spectra were databased for future retrospective analysis. This circumvents the requirement for target analytes prior to …