FGS - Electronic Theses and Practica
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This collection contains University of Manitoba electronic theses and practica.
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- ItemOpen AccessInfluence of Pathogen Strain, Barley Cultivar, and HYD5 Protein on Fusarium Head Blight Progression and Fusarium-Barley Interactions During Malting(2025-05-07) Jayathissa, Anuradha; Badea, Ana (Department of Plant Science, University of Manitoba); Yin, Xiang (Department of Microbiology, University of Manitoba); Zhong, Shaobin (North Dakota State University); Bakker, Matthew G.; Fernando, W.G. DilanthaFusarium head blight (FHB) is a devastating disease in barley, primarily caused by Fusarium graminearum, leading to significant yield loss and mycotoxin contamination, with major economic impacts on the malting and brewing industries. This study hypothesized that variation in Fusarium-related issues during malting may be partially due to differences among F. graminearum strains. Field trials conducted from 2019–2021 used barley cultivars with varying levels of FHB resistance (Newdale and AAC Goldman) inoculated with seven F. graminearum isolates. Disease severity, pathogen density, and deoxynivalenol (DON) content were assessed across years, cultivars, and pathogen strains. Results showed that pathogen strain identity significantly influenced F. graminearum density and DON levels in barley and malt, with Newdale showing higher susceptibility than AAC Goldman. The study also focused on the role of the hydrophobin protein HYD5 from F. graminearum, a surface-active protein associated with fungal pathogenesis and beer gushing. Using a CRISPR-Cas9 system, a ΔHyd5 knockout strain of F. graminearum was generated. The knockout strain showed no significant effect on visual disease severity but resulted in reduced gushing in F. graminearum infected malt. Hyd5 gene expression was elevated during steeping and germination stages of malting, suggesting production of the protein during these phases. Purified HYD5 protein from F. graminearum was sufficient to induce beer gushing, highlighting its potential role in this malting defect. Sequence analysis of HYD5 across Fusarium species revealed interspecies variability, although no intraspecies variation was observed. The findings suggest that managing Fusarium-related malting issues, including beer gushing, requires a deeper understanding of the role of hydrophobins like HYD5 across F. graminearum strains and other Fusarium species that are active in malting environments.
- ItemEmbargoManipulation and utilization of electron-accepting character in π-extended compounds(2025-03-24) Nemez, Dion; Davis, Rebecca (Chemistry); Kuss, Sabine (Chemistry); Liu, Song (Biosystems Engineering); Zysman-Colman, Eli (University of St. Andrews); Herbert, DavidAs the zeitgeist that inhabits a society evolves, the role of the scientist follows close behind. In the current era the modern chemist is charged with many responsibilities, almost all of which require an interdisciplinary approach; from teaming up with biologists to undertake the development of new therapeutic drugs to collaborating with physicists and engineers for the design of functional materials. One responsibility entrusted to the modern chemist is the development of methods and materials that adhere to the principles of sustainability, energy efficiency, and minimized environmental or ecological harm, while maintaining industrial viability. This thesis explores the concepts of environmental consideration and energetic efficiency within the field of chemistry with a focus on the role of unsaturated organic (hetero)cyclic materials, and their ability to accept electrons or electron density. Chapter 2 will outline the development of a sustainable electrochemical method capable of hydrogenating unsaturated organic materials using a glassy carbon electrode, graphite counter electrode, and a mild concentration of acetic acid under an applied mild reductive potential. Highlighting the potential underutilization of electrosynthetic chemistry, an analogue of the industrially relevant molecule cyclandelate is able to be formed using these mild electrochemical conditions with a yield and mass recovery of >99 %. Chapters 3 and 4 will detail the preparation of two highly benzannulated analogues of 2,2'-bipyridine called biphe (Chapter 3) and p-biphe (Chapter 4) and the subsequent investigation into their charge accepting ability for potential use in the development of energy efficient solar harvesting and deep-red emitting devices. For example, the prepared novel heteroleptic complexes Ru(bpy)2(biphe)2+ and Ir(ppy)2(p-biphe)+ showcase deep-red, room temperature phosphorescence, measured at 752 nm and 813 nm respectively. The 3d metal containing complex Cu(xantphos)(p-biphe)+ showcases very deep-red phosphorescence at 77 K containing a long charge transfer lifetime (40 µs), with an emission maximum measured at 811 nm. Chapter 5 continues the study of materials capable of efficient solar harvest but approaches the problem from another angle - utilizing a different organic chromophore framework colloquially referred to as BODIPY, which exhibits highly tunable optoelectronic properties and a very strong molar absorptivity.
- ItemOpen AccessNiche partitioning between sympatrically breeding razorbills and Atlantic puffins during the pre-laying period in coastal Newfoundland(2025-03-25) McOmber, Kristina; Fraser, Kevin (Biological Sciences); Yurkowski, David (Fisheries and Oceans Canada); Davoren, GailTechnological advances in Global Location Sensor (GLS) dataloggers have enabled year-round tracking of seabird location and behavior, providing new insights into their ecology. My thesis used archived GLS datasets from Atlantic puffins (Fratercula arctica, n = 22) and razorbills (Alca torda, n = 28) breeding on the northeast Newfoundland coast (James Island) from 2020-2023. In Chapter 1, I developed a workflow to integrate light and immersion sensor data from these tags to categorize behaviours, including time spent at sea (wet), in burrows/crevices (dry, dark), and at the colony (dry, light). This study highlighted ways to use archived GLS datasets to investigate seabird behavior and phenology during under-studied periods with minimal disturbance. In Chapter 2, I used this workflow to investigate the phenology and time activity budgets of both species during the pre-laying period, when high energy demands for egg formation coincides with low prey availability and, thus, may represent a period of competition. I hypothesized that puffins and razorbills would partition their niches along multiple axes, including diet and breeding phenology, and that time activity budgets would differ. Razorbills arrived at the colony earlier than puffins but laid later, resulting in a longer pre-laying period. Although arrival was similar among years, both species adjusted lay dates (and hatch dates) among years. Females of both species spent more time at sea in most years, while males spent more time in burrows. Puffins spent more time at sea and in their burrows, but razorbills spent more time at the colony outside their rock crevices. Stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in eggshell membranes (2022- 2023, n ~30 /species/year) indicated no isotopic niche overlap between the two species during pre-laying, with razorbills foraging at a higher trophic level (higher δ15N values) and exploiting a wider range of prey types (greater variation in δ13C values). These findings support the hypothesis that razorbills and puffins partition their niches during pre-laying, suggesting that differences in diet and activity timing may aid coexistence when high abundances of multiple species aggregate nearby breeding colonies. Niche adjustments among years, however, suggest phenotypic plasticity to varying conditions.
- ItemOpen AccessRational analysis of empirically designed bridge decks using PUNCHED(2025-04-10) Khan, Saima; Bakht, Baidar (Civil Engineering); Svecova, Dagmar (Civil Engineering); Mufti, AftabReinforced concrete bridge deck slabs make up a significant portion of bridges worldwide and are designed to efficiently withstand traffic loads. The empirical design method, specified in the Canadian Highway Bridge Design Code (CHBDC), uses the inherent arching action in these slabs to provide strength and durability. The PUNCH program was developed to analyze externally restrained steel-free bridge deck slabs, but it cannot analyze directly deck slabs with embedded reinforcement. This research focuses on modifying the PUNCH program to enable the analysis of internally reinforced deck slabs by introducing the concept of equivalent diameter for embedded reinforcement. The study investigates how the axial stiffness of steel-concrete composites changes under varying loads and integrates these findings into the modified program, PUNCHED. The enhanced program accounts for equivalent diameters to accurately model reinforced concrete deck slabs under different loading conditions. Validation using experimental data from multiple studies confirms that PUNCHED reliably predicts both load-deflection behavior and ultimate failure loads. The findings demonstrate that the modified PUNCHED program provides a dependable tool for engineers to evaluate the performance of reinforced concrete deck slabs. By bridging the gap between empirical design and analytical modeling, this research contributes to more precise and effective analysis of bridge deck slabs.
- ItemEmbargoEffects of chickpea milling and pretreatment on the physical and microstructural characteristics of enriched bread and pasta(2025-04-29) Ukoji, Obasi Ukpai; Jian, Fuji (Biosystems Engineering); Erkinbaev, Chyngyz (Biosystems Engineering); Paliwal, JitendraChickpeas, with their rich nutritional profile, present a promising ingredient for food enrichment. However, their incorporation into staple foods such as pasta and bread requires understanding the effects of milling and pretreatment of chickpeas on their microstructural behaviour in chickpea-wheat blend formulation. This research investigates the impact of milling and pretreatment methods on the microstructure and physicochemical properties of chickpea-enriched wheat staple products using X-ray microcomputed tomography (X-ray µCT). Chickpeas were milled using a multi-stage roller mill and a single-stage (Ferkar) mill, yielding five flour types: four flours were obtained from the roller mill (viz., high-protein flour, low-protein flour, reconstituted whole flour, straight-grade flour), and one flour from Ferkar mill (Ferkar-milled flour). These flours were blended with durum wheat semolina in equal amounts for pasta production. The effects of three pretreatment methods - germination, micronization, and roasting - were also studied before milling the chickpeas into straight-grade flour and blending it (in a 20:80 ratio) with wheat flour for bread production. Physicochemical analysis revealed significant differences (p < 0.05) among pasta samples, with high-protein flour pasta exhibiting lower optimum cooking time, reduced cooking loss, and higher protein and ash contents. Microstructural analysis showed that the high-protein blend resulted in low porosity with closed pores and increased structural thickness, contributing to enhanced firmness and texture. Similarly, the physicochemical properties of chickpea-enriched bread were influenced by roasting and micronizion pretreatment methods, with significant (p < 0.05) effects on loaf volume, colour, and protein content. The microstructural evaluation demonstrated that bread made from germinated chickpeas exhibited superior pore structure, leading to improved overall quality. In conclusion, this study provides valuable insights into optimizing chickpea milling and pretreatment methods for integration into staple foods such as pasta and bread. Given the rising demand for alternative protein sources, incorporating chickpea flour with minimal microstructural impact presents opportunities for innovation and sustainability within the food industry.