FGS - Electronic Theses and Practica
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This collection contains University of Manitoba electronic theses and practica.
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- ItemEmbargoDistributed six-port reflectometer based vector network analyzer with multiple measurement techniques and applications for microwave imaging(2025-01-23) Hashir, Muhammad; Mojabi, Puyan (Electrical and Computer Engineering); Isleifson, Dustin (Electrical and Computer Engineering); LoVetri, Joe; Gilmore, ColinThis thesis presents the design and measurement of a distributed six-port reflectometer-based vector network analyzer. The design has been proven to operate with two independent RF power sources. This novel approach makes our system the first-of-its-kind in the world having the capability for accurate phase measurements of distant antennas and other devices which previously required long coaxial cables incurring high-cost and loss of accuracy due to resulting long cable losses. The specific distributed network analyzer reported on herein has a bandwidth of 0.6-1.2 GHz. The study also evaluates three characterization-based measurement techniques, and two calibration-based measurement techniques reported in the literature and draws a comparison based on their performance when used with the current hardware. A test case has been proven for applications of the current hardware to measure the path characteristics in Microwave Imaging applications. A novel approach for determining the reflection and transmission coefficients of the device under test (DUT) has been introduced and validated, utilizing two characterization-based techniques based on non-linear optimization and a geometrical solution. The results were confirmed using a simulation software (ADS) as well as full experimental results using a custom-built measurement hardware. The novel approach allows accurate S-parameter measurements while increasing computational efficiency and using a lesser number of calibration loads as compared to many previously proposed techniques. Although measurement techniques requiring the full S-parameters of the six-port circuit as well as those not requiring the full S-parameters have been tested, our study found that the characterization-based techniques using S-parameters to be more accurate when performed using our custom measurement hardware.
- ItemEmbargoComparative study on nutritional characteristics and physicochemical properties of ancient wheat species(2025-01-20) Deyalage, Sathsara Thakshani; Malunga, Lovemore (Food and Human Nutritional Sciences); Thandapilly, Sijo Jospeh (Food and Human Nutritional Sciences); Malalgoda, ManekaBackground & objective: Ancient wheat species, such as einkorn, emmer, and spelt, are gaining increased attention due to their environmentally friendly nature, which aligns with sustainable agriculture practices, and the rising consumer demand for nutrient-dense food options. Despite their growing recognition, the full potential of these ancient wheat remains largely unexplored, hindering their future food applications. Therefore, this study aimed to address this gap by comprehensively evaluating the nutritional profiles and physicochemical properties of einkorn, emmer, and spelt in comparison to common hexaploid Canada Western Red Spring (CWRS) wheat. Methodology: Nutritional characteristics were assessed through analyses of proximate composition, amino acid profile, phenolic acid content, and in vitro starch and protein digestibility (IVPD). Physicochemical properties were evaluated with a particular focus on the starch and protein profiles of these species. Findings: Einkorn demonstrated higher protein content (21.27%) and phenolic acid content (both free and conjugated), along with lower starch levels compared to other wheat species. Spelt had the highest bound phenolic acid content. In terms of starch digestibility, einkorn was characterized by lower glucose release and reduced rapidly digestible starch (RDS) levels, while refined common wheat (CWRS RF) exhibited the highest RDS and glucose release. Among the ancient wheat species, emmer had the highest glucose release and RDS content. IVPD was highest in CWRS RF (86.05%), with einkorn following closely at 84.29%, while spelt and emmer exhibited lower IVPD values. Lysine was the limiting amino acid in all wheat species. Thermal behavior revealed that spelt had the highest thermal stability with high transition temperatures, while emmer required less energy for gelatinization. Amylose% and amylopectin% showed no significant differences among wheat species. Protein composition analysis indicated significant variations in ancient wheat species, specifically, SDS unextractable glutenin levels were significantly lower in the ancient wheat species compared to common wheat suggesting potential challenges for breadmaking. Conclusion: This study highlights the nutritional significance of ancient wheat species, particularly einkorn, showcasing its potential with higher levels of protein, phenolic acids, and a low-glycemic food profile, along with substantial IVPD. The unique physicochemical characteristics, suggest that processing modifications may be required to optimize the use of ancient wheat in bakery applications.
- ItemOpen AccessEffect of defatting method on the structure and function of moringa seed proteins(2025-01-16) Olukitibi, Abisoye; Kassa, Mulualem (Food and Human Nutritional Sciences); Utioh, Alphonsus (Food and Human Nutritional Sciences); Aluko, RotimiThe global drive for sustainable food systems highlights the potential of underutilized crops like Moringa stenopetala (MS) for their nutritional and functional properties. This study examines the impact of defatting methods on the physicochemical and functional properties of MS protein isolates prepared using alkaline isoelectric precipitation (ISO) and NaCl membrane filtration (MEM_NaCl). Protein isolates were derived from cold-pressed MS meal, both undefatted (UMGPI) and defatted using acetone (AMGPI), hexane (HMGPI), methanol (MMGPI), ethanol (EMGPI; 70%, 7EMGPI; 50%, 5EMGPI), and water (WMGPI). ISO yielded superior protein recovery (41.73 – 83.23%) and content (69.50 – 83.24%) compared to MEM_NaCl, which achieved lower recovery rates (12.96 – 63.67%) and content (28.21 – 72.83%). Thus, ISO-prepared isolates were prioritized for further analysis. UMGPI provided the highest yield, while AMGPI showed superior protein content and solubility (25 – 75%) across pH levels 3 – 9. MMGPI stood out for high amino acid values, while AMGPI exhibited the highest foaming capacity (~80%) and stability at pH 7 and 9. Protein solubility peaked at pH 3. Intrinsic fluorescence revealed weak tyrosine (303 nm) and pronounced tryptophan peaks (348 nm), with MMGPI showing the highest intensity at pH 3. 7EMGPI excelled in in vitro protein digestibility (81.32%) and oil-holding capacity (3.93 g/g). Water-holding capacity was highest in 5EMGPI (2.81 g/g). UMGPI retained the highest phenolic content (1.39 – 1.53 mg GAE/g), while WMGPI had the lowest (0.57 – 1.29 mg GAE/g). Bitterness intensities ranged from 23.34 (MMGPI) to 28.24 (AMGPI). Enzymatic hydrolysis with alcalase (ALH), flavourzyme (FLH), and pepsin + pancreatin (PPH) improved bioactivity. PPH achieved the highest protein recovery (86.23%), superoxide scavenging (25.77 – 84.55%), and metal chelation (4.64%). ALH demonstrated the highest protein content (72.16%), lowest peptide molecular weight (0.38–2.19 kDa), potent ACE inhibition (15.07 – 66.56%), and renin inhibition (24.89 – 51.68%). FLH excelled in pancreatic lipase inhibition (42.06 – 64.38%) and arginase inhibition (13.18 – 34.57%). These findings highlight the role of defatting methods in optimizing MS protein functionality, with AMGPI emerging as a promising candidate for functional foods and nutraceuticals. Enzymatic hydrolysis, particularly with alcalase, further broadens their application potential.
- ItemOpen AccessGenome-wide association analysis within The Manitoba Personalized Lifestyle Research study(2024-12-19) Badurally Adam, Bibi Taskeen; Myrie, Semone (Food and Human Nutritional Sciences); Mackay, Dylan (Food and Human Nutritional Sciences); Taylor, James (Food and Human Nutiritional Sciences); Eck, Peter; Hu, PingzhaoOverall Abstract Background: Obesity is a major public health challenge worldwide and in Manitoba. An estimated 40-70% of obesity is heritable; however, these genetic associations are poorly investigated in the Manitoban adult population using the “gold standard” Dual Energy X-Ray Absorptiometry (DXA) to assess obesity phenotypes. The Manitoba Personalized Lifestyle Research (TMPLR) project enabled a genetic association study in middle-aged Manitobans. Obesity phenotypes considered are total, gynoid, android, arms, legs, and trunk fat mass. Objectives: 1. Perform a systematic review to determine genes associated with obesity phenotypes assessed by DXA in middle-aged cohorts. 2. Develop a “pipeline” to conduct Genome-Wide Association Studies (GWAS) within the TMPLR. 3. Conduct a GWAS on obesity phenotypes within TMPLR. 4. Compare the genes from the systematic review to those from TMPLR data analysis. Methods: The Covidence platform was used for the systematic review. Publications up to July 2023 sourced from Embase and Medline. The methods for the TMPLR project have been published. A GWAS pipeline was established using the Biodata Catalyst bioinformatics platform and the Seven Bridges R studio version 4.1. Results: Out of 94 and 25 studies obtained from Medline and Embase respectively, 14 studies met the eligibility criteria and 13 genes were identified that are associated with obesity-related phenotypes. No significant genome-wide association with obesity was established in the TMPLR cohort. However, 23 loci have had suggestive associations with the obesity phenotypes. Conclusion: There is a lack of high-quality genetic studies that use DXA data and adult populations. No genome-wide associations were reported in TMPLR, likely due to the limited sample size of the cohort. However, a bioinformatics pipeline to analyze genome-wide associations in TMPLR cohort is established and can be used for larger cohorts, such as UK biobanks.
- ItemEmbargoExamining how changes in consumption patterns of specific dietary fibre subtypes are associated with disease development, progression, and outcomes in autoimmune diseases of the gut-brain axis impacted by an altered gut microbiome(2024-12-20) Khorasaniha, Reihane; Myrie, Semone (Food and Human Nutritional Sciences); Suh, Miyoung (Food and Human Nutritional Sciences); Armstrong, Heather; Taylor, CarlaDietary fibres are typically fermented by gut microbes, producing beneficial short-chain fatty acids (SCFAs). In chronic diseases like inflammatory bowel disease (IBD), studies show reduced fibre-fermenting microbiota and SCFAs, alongside worsened symptoms from high-fibre diets, suggesting impaired fibre fermentation may worsen disease outcomes. Our team previously found that select unfermented fibres (e.g., β-fructans) induce gut inflammation and damage in IBD, which was linked to decreased β-fructan consumption. We believe this decrease is a subconscious avoidance of foods associated with worsened symptoms, supporting possible connections between microbiota-driven fibre fermentation and gut-brain axis (GBA) physiology. This further suggests that unfermented fibres' impacts may not be isolated to gut diseases but extend to the nervous system. Given that multiple sclerosis (MS) also shows reduced fibre-fermenting microbiota and SCFA, altered immune pathways, and worsened symptoms on high-fibre diets, I hypothesized that reduced consumption of specific dietary fibres in autoimmune GBA conditions links to lower fibre-fermenting microbiota and worsened symptoms in IBD (gut) and MS (brain). I aimed to: 1) validate our method for examining fibre subtype consumption patterns, 2) assess fibre consumption's association with IBD development and progression, 3) analyze fibre consumption in MS patients, and 4) examine the link between unfermented fibres and CNS damage in experimental autoimmune encephalomyelitis (EAE) mice. I found β-fructan fibre consumption significantly decreased before IBD development (n=3,400) compared to healthy controls, and again during IBD progression from remission to flare (n=155) compared to those in remission. Diet was assessed using a validated food frequency questionnaire (FFQ), with results linked to microbial metabolites. MS patients also consumed significantly less β-fructan than healthy controls. Germ-free EAE MS mice displayed increased spinal demyelination and inflammatory markers in the gut and spine. My findings, described in my thesis, suggest that reduced β-fructan consumption in autoimmune GBA diseases may stem from learned avoidance due to symptoms from reduced β-fructan fermentation. Further research is needed to translate findings clinically for precision nutrition strategies in these diseases.