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Mycobacteria, ATP synthases, and coumarins : a molecular modeling approach to bioenergetics and drug discovery
Full text link1 online resource (x, 278 pages) : illustrations (some colour), charts (some colour), graphs (some colour)Includes abstract and appendices.Includes bibliographical references (pages 22-25, 48-51, 92-95, 107-109, 154-156, 204-219, 278).This thesis blends computational and experimental approaches to molecular design, bioactivity, and bioenergetics across multiple chemical and biophysical systems. The first part develops a high-throughput workflow to analyze electrostatic potential landscapes in 178 experimental structures of the enzyme Fo-F1 ATP synthase, revealing distinct electrostatic behaviors between the human and non-human enzymes and proposing implications for chemiosmotic efficiency and metabolic energetics. The second part reports rigorous theoretical studies of the dipole-moment origin problem in charged biological macromolecules and the quantization of angular momentum in rotatory molecular motors such as ATP synthase, with their implications for molecular observables. The last part reports the synthesis and pharmacological evaluation of novel coumarin derivatives, where cheminformatics techniques unravel potent antibacterial and anticancer leads. Together, these studies bridge chemical biology, quantum chemistry, and biophysical modeling to design novel anticancer and antibacterial therapies and to uncover central aspects of intermediary metabolism that appear to have been overlooked.</p
Comparison of sperm availability in hybridizing male Fundulus heteroclitus and F. diaphanus in Porters Lake, Nova Scotia
Full text link1 online resource (39 pages) : graphsIncludes abstract.Includes bibliographical references (pages 31-39).Hybridization between related species is relatively common in fishes. This can occur
asymmetrically, where contributions from each species are primarily maternal or paternal,
respectively. In Porters Lake, Nova Scotia, two species of Fundulus with different salinity
preferences co-occur at intermediate salinities and hybridize asymmetrically. At high densities, sperm competition can play a vital role in determining the variance in reproductive
success among males. The objectives of my research were to compare sperm availability of
male F. heteroclitus and F. diaphanus, and to examine how conspecific and heterospecific
ovarian fluid affect sperm motility and activation. This study showed that F. heteroclitus
sperm were more motile and abundant than F. diaphanus sperm, and there was no significant
difference between ovarian fluid of each species. These results lend insight on the importance of quantifying sperm availability and motility, and the effect of ovarian fluid on sperm movement in a hybridization context
Seeding change : examining mobilizing social finance for rural development
Full text link1 online resource (143 pages) : chartsIncludes abstract and appendices.Includes bibliographical references (pages 133-143).This thesis explores how seed funding within the social finance ecosystem can catalyze sustainable development in rural communities. Through a qualitative inquiry, this research investigates how capital flows are shaped by governance structures, financialization, and power dynamics. Drawing on interviews, surveys, and a World Café discussion, the findings reveal that intermediaries, adaptive leadership, and regulatory frameworks play crucial roles in enabling or constraining rural innovation
Examining the soft excess in a sample of active galactic nuclei
Full text link1 online resource (vi, 39 pages) : illustrations, charts, graphsIncludes abstract and appendix.Includes bibliographical references (pages 38-39).In active galactic nuclei (AGN), the soft excess refers to the emission below 2 keV where the flux exceeds the extrapolated high energy continuum. The phenomenon was first observed in the 1980s and there is currently no definitive explanation of its origin. One possible model is blurred reflection, which connects the soft excess to the high energy continuum by combining the contributions of primary X-ray emission with emission reflected off the accretion disk. A second model is a warm corona or warm Comptonization. This deals with two different X-ray sources, the original hot corona is now joined by a so-called warm corona at lower temperatures which is more optically thick and produces a steeper spectrum below 2 keV. In this analysis, both the blurred reflection and warm corona models as well as a combined model are applied to a sample of 64 AGN, including both broad line Seyfert 1s (BLS1s) and
narrow line Seyfert 1s (NLS1s), that were observed between 0.6 - 40 keV with Suzaku.
The best model for each source is determined using the corrected Akaike Information
Criterion (AICc). We find that both populations are best fit with the combined model, while blurred reflection alone produces the worst fit statistics of the three models. We calculate the luminosity ratios for the warm corona and blurred reflection contributions to the soft excess, finding that both populations require significant contributions from both components, while the NLS1s exhibit slightly higher warm corona strengths. We also find correlations between low and high energies in the NLS1s and not in the BLS1s which may indicate that the NLS1s present a more cohesive population or that the two groups host different geometries in their central regions
Timing and nature of mafic magmatism and iron-alkali-calcic metasomatism at Clarke Head, Nova Scotia
Full text link1 online resource (90 pages) : illustrations (some colour), maps (some colour), charts (some colour), graphs (some colour)Includes abstract and appendices.Includes bibliographical references (pages 76-84).The objective of this project is to constrain the timing of mafic magmatism and metasomatism at Clarke Head, Nova Scotia, and to discern their relationships to metasomatic occurrences along the Cobequid-Chedabucto Fault Zone (CCFZ). Clarke Head is located within the CCFZ, a 300 km E-W striking, terrane-bounding fault system that hosts numerous metasomatic iron ± copper, gold, and cobalt deposits suggested to be part of a Metasomatic Iron Alkali Calcic system. The source of metasomatic fluids may be from the melting or dissolution of Viséan-aged Windsor Group carbonates and evaporites by mafic magmatism. Field evidence of mafic rocks north of and east along the CCFZ indicate syn- to post-Viséan magmatism occurred. Clarke Head exposes a megabreccia, bounded to the north by the Clarke Head fault, a NE-SW striking fault splay of the CCFZ, that incorporates igneous and sedimentary blocks of varying size, age, and deformation history. Metasomatism related to the undated igneous blocks at Clarke Head may be related to this hydrothermal event. Field work and petrography aided by scanning electron microscopy and micro-X-ray fluorescence spectroscopy show that primary minerals in monzodiorite and gabbro blocks, consisting of andesine-labradorite, are overprinted by metamorphism followed by metasomatism. The metamorphic assemblage consists of Cl-rich hornblende-pargasite-actinolite + Cl-F-rich apatite + LREE-rich epidote + magnetite + hematite + Co-rich pyrite ± Cl-rich biotite, consistent with greenschist/amphibolite facies metamorphism. Three hydrothermal alteration events are shown through assemblages consisting of: i) apatite + chlorite + scapolite ± oligoclase ± albite ± pumpellyite ± quartz ± K-feldspar, ii) analcime, and iii) calcite. In-situ U-Pb Laser Ablation Inductively Coupled Plasma Mass Spectrometry of hydrothermal and altered primary apatite yielded no successful ages due to low U contents (<0.1 ppm). Results
show alteration may be related to alteration at the Bass River Fe-Co prospect and the West Moose River pluton
The problem of benevolence : a case study of the “philanthropic abduction” of the Delaney children
Full text link1 online resource (v, 1 unnumbered, 252 pages) : illustrations, mapsIncludes abstract and appendices.Includes bibliographical references (pages 244-252).This thesis explores the intersection of gender, class, and child welfare in late Victorian
society through a case study of Emma Maitland Stirling (1838-1907) and her legal battle with
working-class widower Arthur Delaney (c. 1860-1907) for custody of his children. Stirling, an
upper-class philanthropist involved in the British Home Child migration movement, leveraged
prevailing social and moral norms to legitimize her custody of the children. Drawing on archival material from Scotland and Nova Scotia, alongside reform literature and personal testimonies, this study examines how Stirling deployed gendered assumptions of female benevolence and class prejudice to maintain control over vulnerable families. By analyzing court proceedings, social reform discourse, and Stirling’s published defences, the thesis argues that child-saving philanthropy often functioned as a tool of social control. This work contributes to a deeper understanding of how philanthropic authority could be exercised to undermine working-class paternal rights under the guise of moral reform
Combining QuEChERS and multi-dimensional liquid chromatography for the analysis of fungicides in produce Items
Full text link1 online resource (xii, 94 pages) : charts (some colour), graphsIncludes abstract and appendix.Includes bibliographical references (pages 79-87).The broad term ‘pesticide’ encompasses a variety of chemicals belonging to subcategories including insecticides, herbicides, and fungicides.1 The latter, fungicides, is the type of pesticide studied in this thesis research. Despite the beneficial properties of pesticides for regulating crop pests, they have also been shown to threaten the health of human organs and systems.2 The health concerns of pesticides are widespread and can be both acute and chronic.2 Acute health effects include irritation and burning of the skin, mouth or nose, and more urgent responses such as impaired cognition and seizures.1 Potential chronic repercussions include detriment to reproductive, pulmonary, and neurological health.1 In recent years, pyrimethanil (PYRI), fludioxonil (FLU), boscalid (BOS), and pyraclostrobin (PYRA) were commonly detected in produce items by the Environmental Working Group (EWG).2
This research focuses on developing a two-dimensional liquid chromatographic (2D-LC) method for the separation, detection, and quantification of PYRI, FLU, BOS and PYRA in produce items. With this goal in mind, a 2D-LC heart-cutting method was developed, which produced properly resolved, symmetrical and sharp peaks in both separation dimensions. Interday coefficients of variation (CV) for retention times and peak areas ranged from 0.093% – 7.352 % in both dimensions. A modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) clean-up procedure was employed for the clean-up of produce samples.5 Second dimension (2D) recoveries were determined to range from 51.3% ± 1.4% to 75.3% ± 2.1% for all analytes. Internal standard calibration was completed for all fungicides using phenanthrene as the internal standard. The coefficient of determination (R2) for all four calibration curves ranged from 0.990 – 0.992. For 2D analysis, the limits of detection (LOD) ranged from 0.043 – 0.131 mg/mL, while the limits of quantification (LOQ) ranged from 0.143 – 0.436 mg/mL. Using the optimized method, a Nova Scotian and a Peruvian blueberry sample were analyzed.</p
Identification of antifungal metabolites produced by microbes inhibiting the growth of Pseudogymnoascus destructans
Full text link1 online resource (54 pages) : illustrations (some colour), graphsIncludes abstract.Includes bibliographical references (pages 50-54).White-Nose Syndrome (WNS) is a fungal disease that has caused significant mortality in
hibernating bat populations across North America, with Pseudogymnoascus destructans being identified as the causative agent. The disease disrupts normal hibernation patterns, leading to increased metabolic demands and depletion of energy reserves, ultimately resulting in high mortality rates. Given the sensitivity of cave ecosystems, microbe-derived antifungal treatments offer a promising approach for WNS management. This study investigates the potential of a bacterial isolate (F18), Penicillium herquei, and Trichoderma atroviride to produce secondary metabolites capable of inhibiting Pseudogymnoascus destructans. Sanger sequencing and NCBI BLAST confirmed that the bacterial isolate F18 belongs to Pseudomonas brenneri. In vitro inhibition assays were performed to assess the antifungal activity of the metabolic extracts obtained from the microbes against Pseudogymnoascus destructans. A fraction from P. brenneri displayed consistent inhibitory effects, prompting further chemical analysis. Ultra-high-performance liquid chromatography coupled with diode array detection identified a distinct peak with spectral characteristics similar to a known antifungal metabolite produced by the Pseudomonas genus. The retention behavior of this compound indicated a high degree of hydrophilicity, which agrees with the structure of the known antifungal metabolite. While some fractions from S5 and S2 also
showed antifungal activity, their effects were less consistent
Exploring the coordination chemistry between bismuth (III) salts and N-Heterocyclic carbenes (NHCs) derived from imidazolium salt-based pincer ligands
Full text link1 online resource (ix, 81 pages) : illustrations (some colour), graphsIncludes abstract and appendix.Includes bibliographical references (pages 49-53).N-Heterocyclic carbenes (NHCs) are a novel class of compounds that have attracted considerable interest in synthetic chemistry due to their strong δ-donating and weak π-accepting properties, as well as their characterization as soft Lewis bases. These features contribute to their enhanced stability and reactivity, making them valuable ligands in both transition metal and main group chemistry. This thesis aims to generate free NHC species through the deprotonation of structurally distinct imidazolium salt-based pincer ligands. Synthesis of the ligands, which feature either an imidazolium or benzimidazolium core, is improved upon by employing the use of a microwave reactor rather than conventional heating. Preliminary characterization demonstrated the successful formation of a carbene species; however, attempts to isolate the free carbenes or directly coordinate them to bismuth were unsuccessful. Despite this, the optimized ligand synthesis and evidence of carbene formation represent promising steps toward the development of novel NHC-based systems for future applications in main group element chemistry.</p
The influence of sex ratio on mating system structure in Japanese medaka (Oryzias latipes)
Full text link1 online resource (40 pages) : charts, graphsIncludes abstract.Includes bibliographical references (pages 37-40).Ecological factors such as the sex ratio in a population can influence the intensity of sexual selection, which determines the evolution and ecology of a population’s mating system. When a population is male-biased there will be more competition between males to secure limited mates compared to populations with a balanced sex ratio. Japanese medaka (Oryzias latipes) are a species of freshwater fish that occur throughout Southeast Asia. Two well studied populations are known to differ in naturally occurring sex ratio. In my study, Japanese medaka competed for mates in four different sex ratios (0.5, 1, 2, and 5 males:females). Two
microsatellite loci were amplified from fish in the founding and most recent generation of a labbred population. The allele frequencies at these loci were compared across the sex ratios. I found that the distribution of alleles when comparing sex ratios in the founding generation was statistically similar between all ratios except for the OSR 0.5 and 5 comparison at locus 35, suggesting that fish sorted into sex ratio selection lines in the founding population were
genetically homogenous. When comparing allele distributions in each sex ratio between
generations, OSR 0.5, OSR 1, and OSR 5 had statistically different distributions at locus 02 and OSR 0.5 at locus 35. Observed heterozygosity increased in all sex ratios at locus 35 and
decreased at OSR 0.5 and 5 at locus 02. At locus 35 there was a significant interaction between OSR and generation when examining heterozygosity. These results suggest that differences have occurred due to the extreme limit of one sex for mating. However, other factors such as genetic drift may also be occurring. Further work investigating the behaviors and morphologies of the individuals in the populations is required to gain a full understanding of the mating systems