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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.

 

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Open Access
Scanning photoelectrochemical microscopy and its application to living cells
(2025-03-27) Thomas, Nikita Maria; Chen, Aicheng (University of Guelph); Gertsein, Aleeza ( Microbiology and Statistics); Tommy, Gregg (Chemistry); Sean, McKenna (Chemistry); Kuss, Sabine
Living cell electrochemistry enables the non-invasive qualitative and quantitative measurement of metabolite and biomarker flux from individual or groups of cells. Scanning electrochemical microscopy (SECM) is an electroanalytical technique that allows for real-time detection of species flux from living cells. This thesis emphasizes the importance of maintaining optimal physiological conditions during SECM and explores the advancement of SECM to scanning photoelectrochemical microscopy (SPECM) for studying living cells. The first part of this thesis investigates the effects of experimental parameters such as temperature, media composition, and light on cellular electrochemical signals. It is shown that maintaining ideal physiological conditions is crucial for reliable SECM and SPECM data. Studies on Adenocarcinoma cervical cancer (HeLa) cells across different temperature ranges reveal inconsistent cellular electrochemical reactivity with small deviations from physiological temperature. However, HeLa cells demonstrate enhanced and stable electrochemical signals when cultured in serum-free media under constant light exposure. To advance SECM to SPECM, the integration of optical fiber (OF) probes is explored to enhance both electrochemical and spectroscopic capabilities. A new, easy-to-fabricate micro-optical ring electrode (MORE) is introduced, with its functionality assessed through electrochemical analysis, numerical modeling, scanning electron microscopy (SEM), and spectroelectrochemistry. The MORE, integrated into SPECM, is used for localized irradiation and as an electrochemical sensor for quantitative analysis of single algal cells. This proof-of-concept demonstrates the potential of applying SPECM to mammalian cells. SPECM is further applied to skin cells for the detection of reactive oxygen species (ROS) and melanin production, which are elevated in response to external stimuli. Overall, a comprehensive exploration of the application of SPECM to mammalian cell studies is investigated with suggestions for future research, highlighting its potential in diverse applications.
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Open Access
Discovering and dreaming: long-term care healthcare aide perceptions of structural empowerment
(2025-03-17) Elias, Jocelyn; Care, Dean W. (Nursing); Doupe, Malcolm (Community Health Sciences); Scanlan, Judith
Background and objective: Chronic and emergent care challenges have led to diminished quality of care in many long-term care (LTC) facilities during the COVID-19 pandemic and beyond. Healthcare aides (HCAs) occupy a strategically important role in achieving improved resident care outcomes yet continue to experience disempowerment through authoritarian working conditions. The aim of this study was to develop a robust description of HCA perceptions of how organizational structures empower them and the desired dream state for such structures. Approach: This study used a qualitative descriptive research design informed by Kanter’s theory of structural empowerment within an appreciative inquiry (AI) framework. AI was chosen for its optimistic egalitarian approach towards organization change; it provided a platform for HCA voices to be heard, protected, and valued. Sampling used volunteer participants and involved convenience and snowball sampling. Ten HCA participants were recruited from four Winnipeg LTC sites. Semi-structured virtual interviews were used to gather rich descriptive data, allowing for an understanding of participant perspectives. Findings: Two main themes emerged from the data: i) What is Important to Healthcare Aides; and ii) Challenges. These participants care about their residents, their job satisfaction and team functioning but experience numerous challenges in their work. They lack access to opportunities for education, resources (i.e., staffing and time), and support from managers and organizations; they also endure difficult, stressful, and dangerous working conditions and retention is inadequately prioritized by the LTC sector. Modifiable organizational structures have the potential to improve resident care by empowering healthcare aides and may to be mediated by the functionality of teams and the use of regular healthcare aides. Conclusion: Empowering healthcare aides is a means to improve the well-being and satisfaction of these essential workers and represents a strategy for ensuring these workers have what they need to provide quality care to residents.
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Open Access
Determining the role of ZEB1 and ZEB2 in controlling fibroblast activation
(2025-03-26) Pallikkara Suresh, Rohini; Netticadan, Thomas (Physiology and Pathophysiology); Dhingra, Sanjiv (Physiology and Pathophysiology); Rastegar, Mojgan (Biochemistry and Medical Genetics); Wigle, Jeffrey
Myocardial infarction (MI) is a leading cause of death in Canada. The activated fibroblast, also known as myofibroblast, is a key player in extracellular matrix production, remodeling, and fibrosis in the heart following a MI. Previous studies in our lab have shown that the transcription factor ZEB2 is expressed in activated cardiac fibroblasts and that the overexpression of ZEB2 upregulates the expression of the myofibroblast markers -SMA, SMemb and ED-A fibronectin. The Zinc finger transcription factor family proteins ZEB1 and ZEB2 have crucial roles in embryonic development, angiogenesis, Epithelial-Mesenchymal transition (EMT), and Endothelial-Mesenchymal transition (EndoMT). This study was focused on determining the role of both ZEB1 and ZEB2 in cardiac fibroblast activation. We compared the protein levels of ZEB1 and ZEB2 in primary adult male and female rat cardiac fibroblast cells during the process of fibroblast activation in vitro. As well, we analyzed the effect of over-expression and knockdown of ZEB1 and ZEB2 in the mouse NIH3T3 embryonic fibroblast cell line. Our results show that both ZEB1 and ZEB2 are expressed in the activated fibroblasts with their expression being highest at 48 hours and then decreasing. We observed that ectopic expression of ZEB2 in both NIH3T3 cells and rat primary cardiac fibroblasts resulted in a corresponding decrease in endogenous ZEB1 expression. Furthermore, siRNA mediated knockdown of ZEB2 resulted in increased ZEB1 expression in cardiac fibroblasts and NIH3T3 cells. Similarly, ZEB1 knockdown resulted in increased ZEB2 expression. This shows that ZEB1 and ZEB2 may form a negative feedback loop to maintain an optimal level of their expression in cardiac fibroblasts. ZEB1 and ZEB2 may directly compensate for the loss of the other transcription factor in fibroblasts. Interestingly, despite these regulatory interactions, the expression of the myofibroblast markers, -smooth muscle actin (SMA) and Embryonic smooth muscle heavy chain (SMemb), remain ZEB1 and ZEB2. This study enhances our understanding of the complex interplay between ZEB1 and ZEB2 in cardiac fibroblast activation and provides new insight into the regulatory mechanism underlying this process. These findings could have significant implications to develop new therapeutic strategies for myocardial infarction and heart failure by targeting ZEB1 and ZEB2 to control fibroblast activation and fibrosis.
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Open Access
Rigidity properties of operator systems and partial order relations in the state space of C*-algebras
(2025-02-24) Saikia, Hridoyananda; Martin, Robert (Mathematics); Zorboska, Nina (Mathematics); Kennedy, Matthew (University of Waterloo); Clouâtre, Raphaël
Arveson’s hyperrigidity conjecture concerns the unique extension property of *-representations of a C*-algebra with respect to a generating operator system. The maximal states in the dilation order fully encapsulate the cyclic representations of a C*-algebra with the unique extension property. A reformulation of the conjecture by Davidson and Kennedy raises the question whether the maximal measures in the dilation order are concentrated on a particular set. In this thesis, we address this question for general C*-algebras. We show the existence of a projection such that the dilation maximal states are precisely those states which are concentrated on the projection. We also reformulate the conjecture in terms of the non-commutative topological properties of this projection. Choquet order is a partial order defined on the set of regular Borel probability measures on a compact convex set. With the help of two equivalent characterizations of Choquet order, we define strong dilation relation and sub-division relation on the state space of a C*-algebra. The equivalence of the two relations is not known in general. We show that the strong dilation relation is stronger than the sub-division relation. Moreover, we show the equivalence of the strong dilation relation with a non-commutative sub-division relation. We also demonstrate that these relations can serve as valuable tools for investigating certain rigidity properties of a generating operator system of a C*-algebra.
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Open Access
Logos, sin, and moral transformation in Origen’s De Principiis 3.1
(2025-03-27) Falk, Jerome; Joyal, Mark (Classics); Barter, Jane (University of Winnipeg); Marx, Heidi
Origen of Alexandria’s treatise on “self-determination” (De Principiis 3.1) has proven highly influential for subsequent theological and philosophical discussions of free will. There is still considerable debate about the finer points of Origen’s understanding of “self-determination” (to autexousion) and where his notion of it fits within the broader Ideengeschichte of free will. In this thesis I examine the free will treatise, but focus instead on the role of the Logos in his understanding of human freedom and moral transformation. In chapter one, I trace the historical development of the Logos concept from Heraclitus and the Stoics through Middle Platonism and the Biblical Platonists, particularly Philo and Clement of Alexandria, to provide a contextualization of Origen's doctrine. Then, on the basis of this contextualization, I argue (in chapters two and three) that Origen's Logos is not a neutral rational faculty but possesses a paraenetic quality, actively prompting moral agents toward virtuous action. By analyzing Origen's psychology of self-determination, especially his use of aphormē (“prompting”), I demonstrate how the Logos influences the moral choices of rational beings. In chapter four I articulate and motivate what I call the "problem of noetic sanctification" in Origen's theology, and in the fifth and final chapter I propose a solution to the problem on Origen’s behalf in which the Logos within each rational being provides a persistent, pre-cognitive motivation towards goodness, thereby facilitating noetic sanctification through interaction with Christ as the cosmic Logos and "light."
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Embargo
Passive wireless sensors based on contactless air-filled substrate integrated waveguide technology
(2025-02-20) Amirkabiri, Amirmasoud; Swatek, David (Electrical and Computer Engineering); Khoshdarregi, Matt (Mechanical Engineering); Amaya, Rony (Electronics, Carlton University); Kordi, Behzad; Bridges, Greg
This thesis aims to develop a chipless passive sensor capable of accurately measuring the time-varying electric field up to 14 kVpp/m with a dynamic range of 3 Hz to 1 kHz near high-voltage apparatus. It also has a sensitivity of 1.86 (kHz)/(V/m), and can be interrogated from a distance of 80 cm. The feasible maximum bandwidth of the external electric field is up to 50 kHz overall. As a passive device, the sensor requires no power source or batteries. The design features a multi-layered stacked printed circuit board (PCB) structure with a chipless cavity resonator in the industrial, scientific, and medical band of 2.4-2.5 GHz, that is based on contactless air-filled substrate integrated waveguide (CLAF-SIW) technology and includes an air cavity surrounded by a low-impedance electromagnetic band gap (EBG) structure. This design simplifies the fabrication of AF-SIW structures and offers a measured high unloaded Q-factor of up to 1340 while reducing dielectric loss. An aperture-coupled microstrip patch antenna is integrated with the CLAF-SIW resonator creating a compact, robust structure that does not require an external commercial antenna. Calibration techniques and far-field measurement results are presented using a wireless experimental setup to assess the performance of the compact sensor. The sensor resonant frequency is measured using a ringback-based wireless interrogation system. The CLAF-SIW sensor provides a high unloaded quality factor necessary for long- distance ringback-based interrogation. It is designed to detect fast time-varying measurands, such as AC electric fields. The multi-layered stacked sensor design allows easy replacement and modification of ground planes, allowing its use for other sensing applications, such as temperature and strain sensing. This thesis also explores wireless temperature sensing in a far-field scenario, where temperature variations cause shifts in the resonant frequency due to changes in the dielectric constant and dimensions of the structure.
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Open Access
Formers’ understandings of why they engaged with and disengaged from violent social movements in settler-colonial North America and Europe
(2025-03-21) Sheppard-Luangkhot, Tara; Rice, Brian (Kinesiology and Recreation Management); Abuelaish, Izzeldin (Peace and Conflict Studies); Amarasingam, Amarnath (School of Religion, Queen's University); Byrne, Sean
This qualitative research studied how former violent extremists understand the drivers that led them into and out of violent extremist, and terrorist movements in Canada, the USA and Europe, which are continents that are also affected by settler-colonialism. The PI is also a former extremist and used critical autoethnographic, intersectional feminist and Indigenous methodologies. Methods included gathering from interviews with former Incel, Neo Nazi, anti-government and violent, political Islamists, their family members, and non-governmental organizations (NGO) staff, and a talking circle/focus group with formers. The research findings increase knowledge about how to better prevent and intervene into violent extremist and terrorist social movements with more effective practitioner efforts at micro, meso and macro levels of society. Research results demonstrated complex and intersecting drivers of entry and exit from violent social movements, and the importance of systemic policies and praxis, such as improved anti-bullying, mental health and educational resources, policy, and PVE/exit programming to teach effective critical thinking training, cross cultural conflict resolution and dialogue skills. Key findings also suggest that mental health and faith systems assist communities affected by intergenerational effects of colonialism/occupation, war, racism, and patriarchy to build identities, cultural and gender relationships where there is equity and powersharing.
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Open Access
Innate cGAS-STING signaling in Doxorubicin cardiomyopathy
(2025-03-24) Thingnam, Raneeta; Dhingra, Sanjiv (Physiology and Pathophysiology); Rabinovich-Nikitin, Inna (Physiology and Pathophysiology); Kirshenbaum, Lorrie
Doxorubicin (DOX) is widely used to treat a variety of human cancers. However, a well-known but poorly understood side effect of DOX treatment is its cardiotoxic properties, which trigger cardiac cell death and heart failure. Autophagy is a cellular process responsible for the removal and degradation of damaged cellular components and proteins through a lysosomal regulated pathway. Previous research demonstrated that autophagy is impaired in cancer patients and mice treated with DOX. The cyclic GMP-AMP synthase (cGAS) - stimulator of interferon genes STING (cGAS-STING), is part of the innate immunity signaling pathway activated by cellular DAMPs such as nuclear DNA and chromatin associated HMBG1. Activation of cGAS-STING leads to cytokine production and cell death. However, the involvement of cGAS – STING pathway in DOX-cardiomyopathy is not well understood. Herein, we investigated the role of cGAS-STING pathway in DOX-induced cardiotoxicity, as well as explore potential therapeutic interventions. Methods: Neonatal cardiac myocytes (NCMCs) were isolated from 1-2 days old Sprague-Dawley rats and were treated with DOX in increasing doses (0.5µM, 1µM, 2.5µM, 5µM and 10µM). After eighteen hours of treatment, the cells were processed for Western blot analysis to evaluate the protein expression of protein markers involved in the innate immune pathway. To assess the impact of cGAS and STING inhibition on DOX-induced toxicity, cell viability and mitochondrial function assays were performed in presence and absence of the inhibitors on DOX treated cardiomyocytes. Results and conclusion: Our findings demonstrate that in contrast to vehicle treated cells, DNA is present in the cytosol of cardiac myocytes when treated with DOX. This coincided with activation of cGAS-STING pathway, accompanied by elevated expression of NLRP3 and Bnip3 proteins leading to wide spread cell death. Notably, pharmacologic inhibition of cGAS or STING independently suppressed DOX-induced cardiac cell death. Our data reveal for the first time the involvement of cGAS-STING innate signaling pathway in the pathogenesis of DOX cardiotoxicity. We suggest that therapeutic interventions that modulate the innate immune pathway may prove beneficial to preserving cardiac function and mitigating cardiotoxicity in cancer patients treated with Dox.
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Open Access
Imparting bacteria-triggered self-disinfecting properties to a commercial bioengineered collagen-GAG matrix
(2025-03-27) Currie, Sarah; Logsetty, Sarvesh (Surgery); Duan, Kangmin (Oral Biology); Liu, Song
Infectious complications associated with the use of commercial bioengineered collagen-GAG matrices are of concern due to the high incidence of infection, difficulty of accurately discerning the presence of infection, and high cost and delayed wound healing when it becomes necessary to excise infected areas. We modified the collagen layer of a commercial bioengineered collagen- GAG matrix with a ciprofloxacin-based pro-drug “Pro-Cip” anchored to the matrix by a polydopamine layer in a simple one-pot chemistry. An ad-layer coating strategy enriched the surface with Pro-Cip, and various boosters for lipase activity were added to further enhance the antibacterial potency of the coating. The coated bioengineered collagen-GAG matrix exhibited potent antibacterial activity against MRSA and P. aeruginosa, achieving a complete bacterial eradication (no detectable CFU with a detection limit of 33 CFU/mL) within 18 hours at low initial inoculum (~10^4 CFU/mL). When challenged with a higher bacterial burden (10^8 CFU/mL), the coated bioengineered collagen-GAG matrix demonstrated robust antimicrobial efficacy, resulting in 100% (8.0) log reduction in MRSA and P. aeruginosa within 5h contact. Zone of inhibition testing yielded clear zones of up to 25 mm diameter, which highlights the ability of the antibiotic to diffuse into the infected wound after bacteria trigger its release from the coated surface. Furthermore, the surface-modified bioengineered collagen-GAG matrix retained excellent cell- adhesion and proliferation, and cell viability remained at 95% after exposure to membrane elutions compared to the unmodified bioengineered collagen-GAG matrix. The self-disinfecting properties of the modified bioengineered collagen-GAG matrix are anticipated to significantly enhance patient outcomes by mitigating the substantial risk of infections, a critical factor in the management of severe wounds such as burns.
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Experimental and numerical analysis of steel I-multigirder bridges under traffic loads
(2025-03-27) Manouchehri, Navid; Svecova, Dagmar (Civil Engineering); Cha, Young-Jin (Civil Engineering; Fiorillo, Graziano
This thesis investigates two critical aspects of bridge engineering: the fatigue life of bridges under traffic loads and the impact of cold temperatures on their ultimate capacity for composite I-girder bridges. The first part of the study examines the fatigue resistance of continuous steel I-girder bridges, analyzing the influence of girder profiles and stress concentrations on fatigue damage. Monte Carlo simulations indicate that optimizing girder geometry can reduce the risk of fatigue damage by up to 35% over a 75-year service life. The second part of the study explores the structural behavior of steel I-girder and reinforced concrete deck bridges under cold temperature conditions. Experimental testing using a scaled bridge model subjected to four-point bending tests demonstrated a 10.3% increase in ultimate load resistance in cold conditions compared to tests conducted at normal temperatures. However, this improvement came at the cost of a 44.5% reduction in maximum deflection and a 55.4% decline in ductility for the most deformation-sensitive girder (G1). While cold temperature exposure resulted in a modest increase in strength, these findings provide valuable insights for designing bridges in cold climates.