MSpace

MSpace is the University of Manitoba’s Institutional Repository. The purpose of MSpace is to acquire, preserve and provide access to the scholarly works of University faculty and students within an open access environment.

 

Recent Submissions

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Open Access
The role of innovation and adaptation technologies in climate change-induced disaster risk reduction: enhancing resilience in Satkhira communities of Bangladesh
(2024-02-29) Khan, Sabbir Ahmed; Agrawal, Nirupama (Natural Resources Institute); Walker, David (Environment & Geography); Haque , C. Emdad
Climate-induced disasters, exacerbated by the changing climate, pose significant threats to the coastal communities of Bangladesh. This thesis investigates the multifaceted strategies of innovation, adaptation technology, and institutional processes to respond to and mitigate the impacts of climatic disasters and strengthen local communities' resilience. The required field data were collected from December 2022 to February 2023 in two coastal Unions of Bangladesh using various Participatory Rural Appraisal (PRA) tools such as key informant interviews, household surveys, and focus group discussions. The research findings revealed that innovation and adaptation technologies emerge as critical components to minimize vulnerability and enhance preparedness in the face of catastrophic events. Innovations such as the Cyclone Preparedness Programme (CPP) help vulnerable communities by disseminating warning information and evacuating them to safer locations with the help of the CPP volunteers. The households avail loans and/or credit from various microfinance institutions (MFIs) to “bounce back” from climatic disasters. Such financial assistance has proven instrumental in facilitating timely repairs and reconstruction of houses in the aftermath of extreme climatic events, while also assisting in restoring livelihood activities and income generation. Adoption of adaptation technology is another strategy that is being widely practiced in the study area to cope with the shocks and stresses arising from climate change. The formal, quasi-formal, and informal institutions were found to be deeply engaged locally in promoting climatic risk reduction efforts. These institutions facilitate the development of livelihood strategies, provide access to credit services, and help in mitigating climatic risks through knowledge sharing within the local community. The policy recommendations from the research underscore the necessity of a comprehensive framework for enhancing the resilience and adaptive capacity of coastal communities. Furthermore, it also emphasizes the integration of innovation and adaptation technologies at the local level for sustainable development.
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Open Access
Design and implementation of low mass short backfire antennas using additive manufacturing
(2024-02-22) Aragbaiye, Yewande Mariam; Ferguson, Philip (Mechanical Engineering); Shafai, Cyrus (Electrical and Computer Engineering); Isleifson, Dustin
This thesis presents research into the design of low-mass short backfire (SBF) antennas with enhanced performance. In the first section of this thesis, modern techniques that can be utilized to decrease the mass of the aluminum SBF antenna were introduced. Two different antenna designs were developed using additive manufacturing and perforation techniques. The first design was created by manufacturing the antenna using additive manufacturing techniques, resulting in a significant reduction in mass. Simulations were conducted on this design to analyze the impact of additive manufacturing on the antenna’s performance. The results indicated that the gain was significantly affected by high levels of surface roughness introduced during the manufacturing process. The second low-mass antenna design, the perforated 3D-printed SBF antenna, combines additive manufacturing and perforation techniques. Parametric studies were conducted on this antenna to determine the optimal size, shape, and arrangement of perforations to achieve the best mass reduction and gain results. Simulation studies found that the antenna with a 3x37 circular array of perforations on its rim, each with a radius of 4.5 mm, performed the best. The simulated results were validated by fabricating and measuring the antennas. The mass of the 3D-printed and perforated 3D-printed SBF antennas were approximately 70% and 80% lighter than the aluminum antenna, respectively, while maintaining minimal loss in gain. The second part of this thesis discusses the enhancement of gain and bandwidth in the SBF antenna. This was done by flaring the rim to increase the aperture size of the antenna. Simulation studies were conducted to examine the impact of rim flaring and rim height on antenna performance. The results of these studies indicate that this technique significantly improved both the gain and bandwidth of the antenna while having minimal effect on the cross-polarization ratio. To further enhance the bandwidth, an iris was introduced to the waveguide feed aperture to obtain better impedance matching. The antenna was then manufactured and tested to confirm the accuracy of the simulations. The measured and simulated results were in excellent agreement.
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Open Access
Optimization of semi-flexible transit operation for low demand scenarios
(2024-02-09) Mishra, Sushreeta; Ojo, Olanrewaju (Mechanical Engineering); Rempel, Garreth (Civil Engineering); Mohamed, Moataz (McMaster University); Mehran, Babak
Many transit agencies in North America suggest semi-flexible transit (SFT) as a viable solution to the growing demand for highly personalized and expensive paratransit services with an increasingly aging population, high operating costs associated with low demand bus transit routes, and lacking adaptability of fixed-route bus transit to serve increasingly diverse spatiotemporal travel needs. This thesis proposes an effective methodology for the optimization of SFT for operation along an under-performing low demand bus transit route in Regina, Canada. In this thesis, three research questions are addressed: (1) What levels of demand are optimal for SFT operation, given the two service delivery models, in-house transit, IHT, and contracted-out taxi, COT? (2) How to optimally design service headway (h) and slack time per trip for route-deviation (Δt) in an integrated SFT that serves both fixed-route and paratransit demand? and (3) What is the optimal vehicle size and vehicle technology for SFT operation when comparing two technologies: battery-electric vehicles (BEV) and diesel-based vehicles (ICEV)? Analytical and metaheuristic optimization techniques are employed to determine the optimal value for decision variables. The findings suggest that SFT with COT delivery model is most economical in terms of operator cost when demand is unexpectedly low, SFT with IHT delivery model is more economical when demand is low to medium, and conventional bus transit operating in-house is more cost-effective when transit demand is high. Operator cost favours solutions with low service frequency (i.e., high h), user cost favours lower ranges of h and Δt, and higher service benefit is derived from high Δt; thus, medium ranges of h and Δt appear to provide the most reasonable trade-off for service. It is also observed that for low demand (5-15 pass/hr), in terms of the total cost (i.e., operator, user, and environmental) a minivan ICEV outperforms all other scenarios as the potential savings in energy cost in favour of BEB were offset by the present high cost of installing fast chargers and when demand increases, minivan BEV outperforms. Besides contributing to the state-of-the-art research on SFT optimization, the study models are used as part of a decision support tool to establish contracting, transit network planning, vehicle technology, operation, and fare policies.
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Open Access
BCL2L13 regulates NSCLC metastasis through mechanisms dependent on mitophagy and anoikis.
(2024-02-16) Alizadeh, Javad; Halayko, Andrew (Physiology and Pathophysiology); Gibson, Spencer (Biochemistry and Medical Genetics); Klonisch, Thomas (Human Anatomy and Cell Science); Rouabhia, Mahmoud (University of Laval); Ghavami, Saeid; West , Adrian
Lung adenocarcinoma comprises about 80% of all lung cancer cases. Metastasis is the major reason for death among lung adenocarcinoma patients. Thus, understanding the determinants of metastasis is critical to improve patient outcomes. Bcl-2–like protein 13 (BCL2L13) is known as a mitophagy mediator that is linked to ceramides lipid metabolism via the inhibition of ceramide synthase 2 and 6 activity. BCL2L13 can also regulate apoptosis. Our preliminary clinical data suggested that not only the BCL2L13 gene expression was significantly downregulated in lung cancer patients with poor survival, but also the BCL2L13 protein expression was significantly reduced in metastatic sites compared to the primary lung tumor in lung cancer patients. We hypothesized that BCL2L13 regulates NSCLC metastasis through mechanisms deponent on mitophagy and detachment-dependent cell death (anoikis). Here, for the first time, we provide evidence that BCL2L13 is involved in regulation of lung adenocarcinoma metastasis via mitophagy-dependent regulation of epithelial to mesenchymal transition (EMT) and anoikis resistance in context of CerS2 and CerS6 activity. Our investigations showed that BCL2L13 is required for the induction of mitophagy in human and mouse lung adenocarcinoma cells. Furthermore, we showed that BCL2L13 knockdown potentiates the TGFβ1- induced EMT and subsequent metastasis and induces anoikis resistance in these two lung adenocarcinoma models. Also, the oxygen consumption rate and hallmarks of mitochondrial bioenergetics (baseline respiration, maximal respiration, spare capacity, non-mitochondrial respiration, and ATP production) were reduced in BCL2L13 knockdown cells, indicating presence of the Warburg effect. Lipidomics findings showed that BCL2L13 knockdown increases levels of CerS2 and 6 related ceramides (C16, C22, and C24) under attached conditions while BCL2L13 overexpression increases levels of these ceramides under anoikis conditions. Lack of BCL2L13 increased while BCL2L13 overexpression decreased the expression of FAK, p-FAK (Tyr 576/577), and p-FAK (Tyr 925) in lung adenocarcinoma cells under anoikis conditions. Also, we showed that NIX and BNIP3 localization was increased while BAX and truncated BID localization was decreased in mitochondria in BCL2L13-KD cells under anoikis conditions. Taking our findings together, we identify BCL2L13 as an important contributor to lung adenocarcinoma metastasis through mitophagy-dependent regulation of EMT and intrinsic apoptosis-dependent anoikis resistance in context of CerS2 and CerS6 activity. Correspondingly, these effects are exerted by BCL2L13 through its role in regulation of ceramides synthesis. Targeting or mimicking BCL2L13 could be considered as a promising novel approach to enhance responses of therapy via sensitizing lung adenocarcinoma cells to undergo anoikis. This could significantly help reduce the metastasis rates in patients with lung adenocarcinoma.
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Open Access
Stock volatility forecasting with transformer network
(2023-12-20) Sababipour Asl, Golnaz; Rouhani, Sara (Computer Science); Thavaneswaran, Aerambamoorthy (Statistics); Thulasiram, Ruppa
Financial world faces many uncertainties due to decisions by governments, business entities, technology trends, natural calamities etc. Stocks and stock market form one of the major activities in financial world. Volatility is one of the main measures of uncertainty in financial stock markets. Hence, forecasting stock volatility is a critical component in many financial problems such as financial risk management, optimizing portfolios etc. In addition to traditional statistical techniques, there have been few artificial intelligence (AI) and machine learning (ML) techniques used in the literature for this volatility forecasting problem. Transformer Network (TN) architecture is one of newest ML techniques. For this thesis work, we utilized TN architecture with multi-head attention (MHA) mechanism for stock volatility forecasting. To enhance the performance of the TN, we incorporated different variations of the feed forward layer. The performance of three distinct TN models was evaluated by implementing three different deep learning (DL) layers (CNN, LSTM, and a hybrid layer CNN LSTM) in the encoder block of TN as the feed forward layer. The results clearly demonstrate that the TN model with the hybrid layer (CNN-LSTM) outperformed the other models, including a recently proposed data-driven approach. Furthermore, we assessed the performance of another latest model that is on built on TN known as Informer model on a minute-scale Bitcoin dataset across various forecast lengths. Our findings underscore the advantages of the Informer model, specifically its ProbSparse attention mechanism and distilling operation, which substantially enhances its efficiency in handling long sequence time-series forecasting (LSTF) tasks.
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Open Access
Understanding the role of odorant receptors in Aedes aegypti larvae
(2024-02-16) Jonson, Elizabeth; Wilkins, Olivia (Biological Sciences); Prehna, Gerd (Microbiology); Whyard, Steve
Worldwide, mosquitoes are of great medical and economic importance due to their profound negative impact on humans. Mosquitoes act as both nuisance pests and disease vectors that account for millions of cases of illness and death annually. They rely on complex olfactory systems for many of their fundamental processes such as finding mates, identifying egg-laying sites, and directly linked to their disease vectoring capabilities, locating blood-meals. Their olfactory systems rely on three major categories of receptors: odorant receptors, ionotropic receptors, and gustatory receptors. These receptors, along with sensors of various environmental cues such as CO2, heat, and humidity, contribute to the mosquito’s chemosensory responses. The yellow fever mosquito, Aedes aegypti, is responsible for the transmission of key diseases such as dengue virus, yellow fever virus, chikungunya virus, and Zika virus. Because of its profound impacts on human health, there is growing interest in exploring new ways to disrupt Ae. aegypti’s olfactory-based behaviours as a means of reducing disease transmission. While there are numerous studies focused on adult mosquito chemoreception, little is known about these processes in mosquito larvae. Here, a chemotaxis response assay was developed to examine which naturally occurring chemicals would attract Ae. aegypti larvae. Mosquito larvae were subsequently fed E. coli bacteria expressing double stranded RNA targeting a larval specific odorant receptor, OR34. RNA interference knockdown of the gene’s transcript was confirmed via qRT-PCR, and chemotaxis assays were used to identify putative odorant ligands to this receptor. This research describes a simple chemotaxis response assay that can be used to identify larval mosquito attractants and an effective way to identify odorant receptors’ potential ligands. Using this information, it should be possible to screen for other ligands that may be used to disrupt mosquito olfaction, and thus develop novel larval mosquito control methods.
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Embargo
The role of PARP-1/TRPM2 signalling in regulating microglial phagocytosis in the context of Alzheimer's disease
(2024-02-16) Lamont, Alana; Dolinsky, Vern (Pharmacology and Therapeutics); Stobart, Jillian (Pharmacy); Jackson, Michael; Kauppinen, Tiina
Chronic neuroinflammation contributes detrimentally to the pathology of Alzheimer's disease (AD), wherein synaptic transmission is diminished, leading to severe cognitive decline. Microglia immune cells drive a number of neuroinflammatory responses, such as release of pro-inflammatory mediators and clearance of beneficial targets (such as pathogens), via phagocytosis. In AD, build-up of excessive amyloid-beta (Aβ) may impact the ability of microglia to efficiently clear such beneficial targets. Previous work has shown that the microglial nuclear enzyme poly(ADP-ribose) polymerase-1 (PARP-1), a driver of pro-inflammatory cellular functions, may also be involved in phagocytic regulation. Inhibition of PARP-1 has been shown to have no impact on beneficial phagocytosis of Aβ targets in conditions representing health. However, whether this beneficial phagocytosis is maintained in the context of amyloidopathy (to mimic one component of AD pathology), has not been examined. PARP-1 has also been shown to act in concert with Ca2+ permeable TRPM2 (Transient Receptor Potential Melastatin 2) channels. In this study, we investigate whether amyloidopathy influences microglial phagocytosis of fluorescently labeled Aβ (FAM-Aβ) and if so, the extent to which the pro-inflammatory PARP-1/TRPM2 signalling pathway is involved. This data shows that PARP-1 and TRPM2 do not have a role in the uptake of Aβ in homeostatic conditions. Further, although amyloidopathy compromises the ability of microglia to engulf Aβ, inhibition of PARP-1 or TRPM2 does not further compromise Aβ clearance by microglia. Thus, a therapeutic targeting the inhibition of PARP-1/TRPM2 in homeostatic conditions should not have any negative effects such as decreased Aβ phagocytosis.
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Open Access
A randomized trial evaluating the utility of non-targeted biopsies for colorectal neoplasia detection in adults with inflammatory bowel disease: a pilot study protocol
(2024-02-01) Murthy, Sanjay K.; Marderfeld, Luba; Fergusson, Dean; Ramsay, Tim; Bernstein, Charles N.; Nguyen, Geoffrey C.; Jairath, Vipul; Riddell, Robert
Abstract Background Persons with inflammatory bowel diseases are at increased risk of developing colorectal cancer and require frequent colonoscopy surveillance. Guidelines recommend taking 30 to 40 non-targeted biopsies throughout the colorectum to detect “invisible” neoplasia in this setting, despite a lack of evidence supporting this practice. We sought to assess the utility of this practice through a randomized controlled trial. We first propose an internal pilot study to assess recruitment potential, protocol adherence and data capture to guide the full trial. Methods We have designed a multi-centre, parallel-group, non-inferiority randomized controlled trial to test the utility of non-targeted biopsies as an adjunct to colonoscopy surveillance for neoplasia detection in persons with inflammatory bowel disease involving the colorectum in routine clinical practice. Participants are randomized 1:1, stratified by study site, to either standard of care high-definition white-light colonoscopy with 32 to 40 non-targeted biopsies of non-neoplastic-appearing mucosa along with a sampling of abnormal-appearing mucosa (control group) or modified colonoscopy with targeted sampling alone (intervention group). The primary outcome for the full trial will be the proportion of persons with ≥ 1 neoplastic focus detected during colonoscopy. For the pilot phase, we will assess the feasibility of recruiting a minimum of 15% of the estimated sample size within 1 year, under identical conditions as the full trial, while maintaining ≥ 90–95% rate of protocol adherence and data capture. These participants will contribute data to the full trial. The trial is being conducted at 12 centres across Canada, with a total sample size of 1952 persons. Discussions The trial protocol has been approved by the ethics committees of all participating sites, and the pilot study has received funding through the Canadian Institutes of Health Research (PJT 159607). If feasibility metrics are met during the pilot phase, we will complete the full trial. The trial outcomes will contribute to update the practice guidelines in this area. Trial registration ClinicalTrials.gov, NCT04067778.
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Open Access
Association between high-density lipoprotein cholesterol and lumbar bone mineral density in Chinese: a large cross-sectional study
(2024-01-24) Sun, Yongbing; Qi, Xin; Wang, Xuan; Lin, Xinbei; Zhou, Yang; Du, Yawei; Liu, Ao; Lv, Xue; Zhou, Jing; Li, Zhonglin; Wu, Xiaoling; Zou, Zhi; Zhang, Michael; Zhu, Jiadong; Shang, Feifei; Li, Yongli; Li, Hao
Abstract Background The association between lipid and bone metabolism, particularly the role of high-density lipoprotein cholesterol (HDL-C) in regulating bone mineral density (BMD), is of significant interest. Despite numerous studies, findings on this relationship remain inconclusive, especially since evidence from large, sexually diverse Chinese populations is sparse. This study, therefore, investigates the correlation between HDL-C and lumbar BMD in people of different genders using extensive population-based data from physical examinations conducted in China. Methods Data from a cross-sectional survey involving 20,351 individuals aged > = 20 years drawn from medical records of health check-ups at the Health Management Centre of the Henan Provincial People’s Hospital formed the basis of this study. The primary objective was to determine the correlation between HDL-C levels and lumbar BMD across genders. The analysis methodology included demographic data analysis, one-way ANOVA, subgroup analyses, multifactorial regression equations, smoothed curve fitting, and threshold and saturation effect analyses. Results Multifactorial regression analysis revealed a significant inverse relationship between HDL-C levels and lumbar BMD in both sexes, controlling for potential confounders (Male: β = -8.77, 95% CI -11.65 to -5.88, P < 0.001; Female: β = -4.77, 95% CI -8.63 to -0.90, P = 0.015). Subgroup and threshold saturation effect analyses indicated a stronger association in males, showing that increased HDL-C correlates with reduced lumbar BMD irrespective of age and body mass index (BMI). The most significant effect was observed in males with BMI > 28 kg/m2 and HDL-C > 1.45 mmol/L and in females with a BMI between 24 and 28 kg/m2. Conclusion Elevated HDL-C is associated with decreased bone mass, particularly in obese males. These findings indicate that individuals with high HDL-C levels should receive careful clinical monitoring to mitigate osteoporosis risk. Trial registration The research protocol received ethics approval from the Ethics Committee at Beijing Jishuitan Hospital, in conformity with the Declaration of Helsinki guidelines (No. 2015-12-02). These data are a contribution of the China Health Quantitative CT Big Data Research team, registered at clinicaltrials.gov (code: NCT03699228).
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Open Access
Scoping review on the link between economic growth, decent work, and early childhood caries
(2024-01-13) Foláyan, Morẹ́nikẹ́ O.; Amalia, Rosa; Kemoli, Arthur; Ayouni, Imen; Nguweneza, Arthemon; Duangthip, Duangporn; Sun, Ivy G.; Virtanen, Jorma I.; Masumo, Ray M.; Vukovic, Ana; Al-Batayneh, Ola B.; Gaffar, Balgis; Mfolo, Tshepiso; Schroth, Robert J.; El Tantawi, Maha
Abstract Background Early Childhood Caries (ECC) is a prevalent chronic non-communicable disease that affects millions of young children globally, with profound implications for their well-being and oral health. This paper explores the associations between ECC and the targets of the Sustainable Development Goal 8 (SDG 8). Methods The scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. In July 2023, a search was conducted in PubMed, Web of Science, and Scopus using tailored search terms related to economic growth, decent work sustained economic growth, higher levels of productivity and technological innovation, entrepreneurship, job creation, and efforts to eradicate forced labor, slavery, and human trafficking and ECC all of which are the targets of the SDG8. Only English language publications, and publications that were analytical in design were included. Studies that solely examined ECC prevalence without reference to SDG8 goals were excluded. Results The initial search yielded 761 articles. After removing duplicates and ineligible manuscripts, 84 were screened. However, none of the identified studies provided data on the association between decent work, economic growth-related factors, and ECC. Conclusions This scoping review found no English publication on the associations between SDG8 and ECC despite the plausibility for this link. This data gap can hinder policymaking and resource allocation for oral health programs. Further research should explore the complex relationship between economic growth, decent work and ECC to provide additional evidence for better policy formulation and ECC control globally.