http://knowledgecommons.lakeheadu.ca:80 the knowledge commons digital repository system captures, stores, indexes, preserves, and distributes digital research material. tue, 31 dec 2024 01:56:12 gmt 2024-12-31t01:56:12z https://knowledgecommons.lakeheadu.ca/handle/2453/5403 hyperpolarized xenon-129 chemical exchange saturation transfer (hypercest) molecular imaging: achievements and future challenges batarchuk, viktoriia; shepelytskyi, yurii; grynko, vira; halen kovacs, antal; aldossary, ruba; talwar, tanu; hasselbrink, carson; ruset, iulian c.; deboef, brenton; albert, mitchell s. molecular magnetic resonance imaging (mri) is an emerging field that is set to revolutionize our perspective of disease diagnosis, treatment efficacy monitoring, and precision medicine in full concordance with personalized medicine. a wide range of hyperpolarized (hp) 129xe biosensors have been recently developed, demonstrating their potential applications in molecular settings, and achieving notable success within in vitro studies. the favorable nuclear magnetic resonance properties of 129xe, coupled with its non-toxic nature, high solubility in biological tissues, and capacity to dissolve in blood and diffuse across membranes, highlight its superior role for applications in molecular mri settings. the incorporation of reporters that combine signal enhancement from both hyperpolarized 129xe and chemical exchange saturation transfer holds the potential to address the primary limitation of low sensitivity observed in conventional mri. this review provides a summary of the various applications of hp 129xe biosensors developed over the last decade, specifically highlighting their use in mri. moreover, this paper addresses the evolution of in vivo applications of hp 129xe, discussing its potential transition into clinical settings. mon, 01 jan 2024 00:00:00 gmt https://knowledgecommons.lakeheadu.ca/handle/2453/5403 2024-01-01t00:00:00z https://knowledgecommons.lakeheadu.ca/handle/2453/5401 enantioselective cross-coupling of monosubstituted ferrocenes in chiral ionic liquids mcgovern, conor planarly chiral ferrocenes have applications in pharmaceuticals, agrochemicals, and biomedical research for their use as ligands or catalysts in asymmetric synthesis. previous methods of enantioselective synthesis of planar-chiral ferrocenes involve directed ortho-metalation with either a pre-installed centrally chiral group or chiral resolution. these methods use sensitive organometallic reagents, have low atom economy, and require additional steps to remove the chiral auxiliary or perform chiral resolution. asymmetric cross-coupling is an enticing alternative, although enantioselective c-h bond activation poses a challenge. n-heterocyclic carbenes including imidazoliums can complex to palladium catalysts to act as a chiral ligand and strong σ donor and have previously been used to achieve c-h activation in arylations of benzaldehydes. this research aimed to achieve enantioselective arylation of ferrocenes, using a catalytic system comprising pd(oac)2, imidazolium salts and cs2co3 to achieve enantioselective catalysis, enabling asymmetric cross-coupling of aryl halides to monosubstituted ferrocenes, which yielded trace amounts of product. the addition of p-benzoquinone and cu(oac)2- acting as oxidants- expands the scope of the reaction to facilitate asymmetric cross-coupling of monosubstituted ferrocenes with aryl boronic acids. additionally, a homocoupling reaction between aryl bromides with 65% yield was developed, which could also offer access to axially chiral biphenyl compounds. the enantiomerically pure compounds created using these techniques have applications in many areas of organic, bio and medicinal chemistry, including drug design, ligand synthesis for asymmetric catalysis and polymer chemistry used in research, medicine, and industry. mon, 01 jan 2024 00:00:00 gmt https://knowledgecommons.lakeheadu.ca/handle/2453/5401 2024-01-01t00:00:00z https://knowledgecommons.lakeheadu.ca/handle/2453/5400 the status of turtle populations in point pelee national park: a 20 year update wick, ian e. long-lived species such as turtles may appear to have healthy persistent populations if adults are consistently observed; however, study of size structures can reveal declining populations left vulnerable by limited juvenile recruitment. longterm studies can provide insight into community and population structure changes as well as test the efficacy of previously implemented mitigation measures. two intensive turtle studies that included trapping occurred in point pelee national park (ppnp) prior to my work: rivard and smith (1973) and browne (2003). browne (2003) studied the populations, capturing six species, and started the ppnp nest protection program to mitigate heavy nest predation causing limited juvenile recruitment in snapping and blanding’s turtle populations. i captured 1834 individuals of five native and one introduced turtle species in 2022–2023 and compared my results with the results from rivard and smith (1973) and browne (2003). the objective of my thesis was to estimate population sizes and compare community structure, relative abundance, sex ratios, and size structures from 2022–2023 with 1972–1973 and 2001–2002 to determine the status of ppnp turtle populations and the efficacy of the nest protection program. a total of 882 nests were protected between 2001–2021; 480 snapping turtle nests and 33 blanding’s turtle nests. i found an increased catch-per-unit-effort (cpue) and a more evenly distributed size structure with a significantly lower median mcl (mm) than browne (2003) for snapping turtles. i found a decreased cpue and a size structure with no significant changes since browne (2003) for blanding’s turtles. [...] mon, 01 jan 2024 00:00:00 gmt https://knowledgecommons.lakeheadu.ca/handle/2453/5400 2024-01-01t00:00:00z https://knowledgecommons.lakeheadu.ca/handle/2453/5399 ground improvement of non-cohesive soil using nanoparticles, specifically, laponite siddique, shumsun nahar ground improvement through densification is a widely used techniques to mitigate the risk of liquefaction and significant soil deformations. traditional site stabilization techniques have certain limitations such as insufficient field treatment, substantial disturbances, environmental pollution, and high costs. however, incorporating nanoparticles into ground improvement techniques can lessen these negative impacts, offering a more efficient and environmentally friendly alternative. this study examines the characteristics of laponite, a promising soil improvement nanoparticle, when it is mixed with non-cohesive soil under full saturated conditions. the findings revealed that laponite is both environmental-friendly and biologically inert. even a small amount of laponite significantly reduces the generation of pore water pressure under static loadings due to its good rheological properties as a transparent gel. additionally, the modulus of elasticity of sand-laponite specimens is nearly double that of pure sand. the swelling strain of compacted laponite increases over time and as the concentration of laponite increased in specimens. laponite also effectively restricts the migration of contaminants and reduces soil permeability due to its repeated swelling performance. moreover, the damping ratio of treated samples is higher compared to untreated sand samples. the damping ratio begins to reduce after reaching its peak and eventually reaches equilibrium in case of sand+ laponite samples. the coefficient of permeability is significantly reduced with the presence of small amounts of laponite in sand samples. the compressive behaviour of laponite hydrogel indicates that laponite hydrogels exhibit the nonlinear stress-strain relationships which represents typical viscoelastic characteristics. this research provides novel insights into the improvement and modification of the properties of non-cohesive soil (sand) elaborately in the presence of laponite, demonstrating its potential as an effective ground improvement material. mon, 01 jan 2024 00:00:00 gmt https://knowledgecommons.lakeheadu.ca/handle/2453/5399 2024-01-01t00:00:00z