Faculty of Graduate Studies Online Theses
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Item Embargo Characterization of ALS Patient iPSC-Derived Motor Neurons(2025-08-01) Reynolds, Paige; Not Applicable; Master of Science; Department of Medical Neuroscience; Received; Dr. Stefan Kruegar; Not Applicable; Dr. Adam Jonhston; Dr. Ying ZhangAmyotrophic Lateral Sclerosis (ALS) is a rapidly progressing fatal neurodegenerative disease. It is characterized by motor neuron (MN) degeneration, which leads to the loss of voluntary movement control and premature mortality. Currently, there is no known cure for ALS. Human induced pluripotent stem cells (iPSC) derived from ALS patients have become a powerful tool to study disease mechanisms and identify therapeutic targets. Dr. Rafuse’s lab at Dalhousie University has established several iPSC lines sourced from both healthy individuals and ALS patients harboring the genetic mutations C9ORF72 or TARDBP. In addition, the introduction of Channelrhodopsin-2 (CHR2), a light-sensitive protein, into these cell lines enables the manipulation of cell activity via light stimulation. Using whole-cell patch-clamp, this study aims to systematically characterize MNs derived from these human iPSC lines. My findings revealed that iPSCMNs derived from ALS patients exhibited an aberrant developmental trajectory, characterized by increased maturation rates under harsher culture conditions, abnormal activity patterns, and an early decline in action potential output and synaptic activity compared to healthy controls. Furthermore, chronic optic activation had minor impacts on the healthy control group, but more significantly influenced the development and intrinsic properties of ALS iPSC motor neurons. This presents a potential avenue for modulating cellular behavior at varying developmental stages, thereby potentially extending ALS cell survival.Item Open Access The Role of Pain Sensitization and Muscle Function in Knee Osteoarthritis Mechanics(2025-08-05) Hannigan, Meaghan; No; Master of Science; School of Physiotherapy (Rehabilitation Research); Received; Dr. Janie Astephen-Wilson; No; Dr. Derek Rutherford; Dr. William Stanish; Dr. Jason McDougall; Dr. Rebecca MoyerKnee osteoarthritis (KOA) pain is frequently in discordance with structural severity, suggesting sensitization mechanisms. However, the relation of pain sensitization with functional demand and properties remains unexplored, neglecting age-related differences. This thesis investigated associations of pain sensitization with functional demand (muscle capacity utilization; MCU), and muscle stiffness (shear wave velocity; SWV) in individuals with KOA, exploring age-related differences. Thirty-one adults with unilateral KOA completed self-reported questionnaires, quantitative sensory testing, strength testing, gait analysis, and quadriceps ultrasound elastography. MCU was calculated during walking and stairs. Pain sensitization was bilateral despite unilateral KOA. MCU was higher in the contralateral limb across tasks. Sensitization and MCU were negatively associated. Quadriceps SWV was moderately associated with sensitization in the affected limb. Sensitization-MCU associations were stronger in younger participants during stairs, and in older adults during walking. Pain sensitization may contribute to age-related functional compensations in KOA, highlighting the need for interventions tailored to symptoms.Item Open Access Development and characterization of sustainable coatings for environmentally benign marine transportation applications(2025-08-01) Sabetbokati, Kazem; No; Doctor of Philosophy; Department of Mechanical Engineering; Not Applicable; Joey Kish; Yes; Ali Nasiri; Vahid Adibnia; Kevin Paul PlucknettThe development and characterization ofsustainable coatings for marine transportation applications is crucial for enhancing the long-term performance and environmental impact of anti-corrosionmaterials. This thesis investigates the effectiveness of eco-friendly corrosion inhibitors incorporated into epoxy-based coatings, focusing on theirperformance under static and dynamic humid conditions, which replicate the challenging marine environment. Through a series of rigorous electrochemical,mechanical, and surface analyses, the study evaluates the water-induced degradation mechanisms of these coatings, the efficacy of various corrosioninhibitors, and the role of novel materials such as graphene in enhancing coating integrity. The research reveals that water-induced degradationsignificantly impacts the performance of epoxy coatings, particularly under salt spray and dynamic flow conditions, leading to coating delamination andreduced protective properties. Incorporating eco-friendly inhibitors into the coatings enhances their resistance to degradation, preserving coating integrityin various humid environments over the long term. The study emphasizes the importance of understanding the complex interactions between environmentalconditions, inhibitor performance, and coating properties. Additionally, the investigation into graphene-embedded epoxy coatings demonstrates the potentialof graphene platelets to improve the barrier properties of coatings, although they can exacerbate corrosion-induced delamination due to reduced interfacialadhesion between the coating and substrate. The use of accelerated aging techniques revealed that while graphene-embedded coatings offered excellentcorrosion resistance, their long-term performance may be compromised by adhesion challenges. This work provides valuable insights into the design andoptimization of sustainable coatings for marine applications, emphasizing the critical role of material selection and inhibitor incorporation to enhance thedurability and environmental compatibility of protective coatings. The findings contribute to advancing the development of more reliable, eco-friendly coatingsfor use in marine transportation, ensuring better corrosion management and environmental sustainability.Item Open Access Coronavirus M Proteins Inhibit Anterograde Protein Trafficking and Secretion(2025-08-05) Caddell, Taylor; Not Applicable; Doctor of Philosophy; Department of Microbiology & Immunology; Not Applicable; Dr. Joyce Wilson; Not Applicable; Dr. Roy Duncan; Dr. Denys Khaperskyy; Dr. Greg Fairn; Dr. Craig McCormickCoronaviruses (CoVs) encode transmembrane proteins, such as Spike, Membrane (M) and Envelope (E), which are translated at the endoplasmic reticulum (ER) and traverse the secretory pathway to converge at sites of virus assembly. Three ER resident proteins, activating transcription factor 6 (ATF6), inositol-requiring enzyme 1 (IRE1), and PKR-like ER kinase (PERK), sense accumulation of unfolded proteins in the ER and initiate transcriptional responses, a process known as the unfolded protein response (UPR). I observed UPR modulation by numerous SARS-CoV-2 proteins including Spike, which activated all three arms of the UPR. By contrast, M inhibited ATF6 but was unable to inhibit activation of IRE1 or PERK. ATF6 has a unique activation mechanism whereby ER stress triggers translocation to the Golgi where ATF6 is processed by proteases to release the transcription factor ATF6-N. M did not inhibit ATF6-N activity; therefore, I reasoned M may inhibit ATF6 trafficking at a step that precedes protease cleavage and release of ATF6-N. Indeed, I observed that ectopically expressed M inhibited several proteins requiring ER-to-Golgi transport, including sterol regulatory element binding protein-2 (SREBP2) and stimulator of interferon genes (STING). M also inhibited the secretion of a soluble Gaussia luciferase protein. Using a cargo sorting assay, I observed M accumulated in the cis-Golgi and inhibited anterograde transport of a transmembrane reporter protein beyond this compartment, while dispersing the trans-Golgi network (TGN). Further investigation determined M co-localizes with cholesterol, suggesting M overexpression alters cholesterol levels at the cis-Golgi, which is known to inhibit protein trafficking from the Golgi. Together, these observations suggest CoV M proteins disrupt anterograde trafficking in the canonical secretory pathway, potentially by directly binding cholesterol causing an imbalance in Golgi membranes. This work identifies a novel role for CoV M proteins, whereby inhibition of protein trafficking inhibits several intracellular signalling pathways and cellular secretion, implicating a larger role for M during CoV replication beyond virion assembly and structure.Item Open Access LONG-ACTING REVERSIBLE CONTRACEPTIVES AND THE RISK OF SEXUALLY TRANSMITTED BLOOD-BORNE INFECTIONS AMONG CANADIANS UNDER 25 YEARS OF AGE(2025-08-05) Simmons, Haylie; Not Applicable; Master of Science; Department of Community Health & Epidemiology; Received; n/a.; Not Applicable; Michelle Dimitris; Sahar Saeed; Nichole Austin; Daniel DuttonThe incidence of sexually transmitted blood-borne infections (STBBIs), specifically chlamydia and gonorrhea, is surging across Canada. Prevention efforts for STBBIs center on the use of barrier methods (e.g., condoms). However, barrier methods are prone to user error and have high failure rates of preventing pregnancy compared to long-acting reversible contraceptives (LARC) such as intrauterine devices (IUDs). Yet, LARC methods do not offer any protection against STBBIs. Given their effectiveness as a contraceptive, use of LARC methods is increasingly recommended by providers for young women. Young women are also disproportionately impacted by rising chlamydia and gonorrhea rates. There is currently little research on the association between increased LARC use and the increase of STBBIs within Canada, which ultimately translates to an important knowledge gap. First, I conducted a policy scan to document provincial variation in LARC coverage across Canada. Second, I assessed the population-level impact of expanded LARC access on chlamydia/gonorrhea incidence among people 15-24 years old. I used a policy that expanded LARC access at the population level in Ontario (known as OHIP+) as a proxy for increased use of LARCs (through increased access). I then estimated the population-level impact of expanded LARC access on chlamydia/gonorrhea incidence using difference-in-differences (DiD) approach and a negative binomial regression analysis. Ontario was selected as the exposed group, and British Columbia (where no change in access occurred) as the unexposed. The outcome of interest was chlamydia/gonorrhea incidence among people aged 15-24 years old and data was provided by Public Health Ontario and The BC Centre for Disease Control. The policy scan found that all provinces had some level of LARC coverage for targeted sub-populations such as low-income families with strict eligibility guidelines. Prior to 2023, few provinces had broad coverage plans with minimal eligibility criteria like OHIP+. The policy scan also confirmed BC was an adequate comparator group for the DiD analysis. I found following the OHIP+ policy change there was an increase in total and female chlamydia cases however, the incidence rate ratio (IRR) was not statistically significant (IRR: 1.04, 95% CI: 0.91, 1.19), while total gonorrhea cases did increase significantly (IRR: 1.30, 95% CI: 1.11, 1.46). These findings suggest that expanded LARC access may be associated with an increase in disease incidence which provides valuable information for clinical and public health practice.Item Embargo WHEN CHATBOTS MEET EMOJI: THE EFFECTS ON CONTINUED USAGE INTENTION(2025-08-05) Wang, Xiaoxu; Not Applicable; Master of Science; Rowe School of Business; Received; n/a; Not Applicable; Kyung Young Lee; Colin Conrad; Qi Deng; Jenny ChenChatbots are increasingly adopted in customer service to offer convenient and timely assistance. However, the effect of adding emojis on user experience remains underexplored. This thesis seeks to fill this gap by investigating how emoji usage influences users’ continuance use intention in different service situations, while also exploring the underlying mechanisms. Results from two experiments indicate that emojis in customer service chatbots positively affect users perceived social presence and attitudes toward the chatbot, which in turn increase their intention to continue using the service. Moreover, the outcome of the service (successful vs. unsuccessful) plays a moderating role. This thesis applies the Computers Are Social Actors (CASA) theory and Language Expectancy Theory (LET) to explore how emoji usage influences user expectations based on service outcomes. Additionally, the findings provide valuable insights for managers and chatbot designers, offering practical guidance on how to improve chatbot services and enhance user satisfaction.Item Embargo AGE AND SEX-DEPENDENT EFFECTS OF DIETARY NITRATES WITH AND WITHOUT EXERCISE ON FRAILTY AND CARDIAC HEALTH IN C57BL/6 MICE.(2025-07-31) Bisset, Elise; Yes; Doctor of Philosophy; Department of Pharmacology; Received; Dr LaDora Thompson; Yes; Dr Kishore Pasumarthi; Dr Ketul Chaudhary; Dr Susan HowlettNitrate supplements are commonly combined with aerobic exercise to potentially improve both performance and cardiac function, but research has mostly used young male participants. Hence, whether this combination improves cardiac function in females or improves age-related cardiovascular deterioration is unclear. It is also unknown whether the combination of exercise and nitrates improves frailty in young or old mice. This study provided young (7-9 mos) and old (24 mos) male and female mice 1 mM sodium nitrate in drinking water, access to a voluntary running wheel, both, or neither for 12 weeks. Health was measured using a frailty index, body composition scan (DEXA), and treadmill fitness test at baseline and endpoint. Cardiac health was assessed in young and old mice using echocardiography, myocardial strain, electrocardiography, blood pressure, and renal blood flow at baseline, midpoint and endpoint. At endpoint ventricular cardiomyocytes were paced at 2 Hz and loaded with Fura-2 dye to measure contractions and calcium transients. Expression levels of calcium handling proteins were measured in ventricular tissue. In young mice both exercise and nitrates prevented detrimental changes in body composition but only the combination of exercise and nitrates improved frailty and increased exercise volume in females. Nitrates alone protected older female mice against detrimental increases in frailty and improved older male body composition while the combination of exercise and nitrates had little effect. Cardiovascular effects were also assessed in young mice. Exercise was beneficial for cardiac structure and function for mostly female mice. While nitrates improved blood pressure, they reduced systolic function in young male mice. The combination intervention abolished most of the beneficial cardiac effects of exercise in female mice. This occurred as nitrates plus exercise negatively impacted calcium handling in young females. In older mice, nitrates improved blood pressure but also decreased systolic function in older female mice. However, in older males the beneficial effects of exercise were largest in nitrate supplemented mice. In conclusion, there were sex and age specific effects of the combination of aerobic exercise and sodium nitrate where the combination was most beneficial in older male mice and detrimental in young female mice.Item Open Access EFFECTS OF CULTURE CONDITIONS ON PHYTOSTEROL CONTENT OF SELECTED MICROALGAE SPECIES AND THE DEVELOPMENT OF A CHLOROPHYLL-BASED RAPID SCREENING PIPELINE(2025-07-31) Adewusi, Oladimeji; Not Applicable; Doctor of Philosophy; Department of Process Engineering and Applied Science; Not Applicable; Dr. Philippe Soudant; Not Applicable; Dr. Hugh MacIntyre; Dr. Su-Ling Brooks; Dr. Suzanne BudgeThis work investigated the potential of four microalgae species, including the haptophyte Diacronema lutheri, Eustigmatophyte Nannochloropsis oculata and the diatoms Phaeodactylum tricornutum and Chaetoceros muelleri, for the sustainable production of sterols. In industrial settings, microalgae cultivation conditions are typically optimized for maximum metabolite production and cost savings. Hence, the first study in this work explored the effects of light intensity on the sterol profile and concentration of cultures harvested at different growth phases. In most cases, cultures grown at medium light level and harvested in stationary phase had the greatest sterol concentration with few exceptions. Notably, Diacronema lutheri had the highest diversity of sterol structures amongst all the species investigated. In the second study, the potential of chlorophyll as a proxy tool to rapidly estimate sterol production was investigated. The results showed that sterol to chlorophyll ratio (Str/Chl) has potential to be used as a coarse estimation tool for sterol concentration in diatoms because of limited intra-species variability. The ratio was however limited in estimating sterol concentration across taxa due to large inter-species variability. The last study explored the effect of lactose as a carbon source on sterols in the mixotrophic cultivation of Diacronema lutheri. The relative abundance of the individual sterol structures of Diacronema lutheri was impacted by lactose supplementation but not the total sterol concentration. Overall, this work has provided valuable insights into the relationship between chlorophyll and sterol and its use in rapid selection high sterol yielding strains. Additionally, this work demonstrated the metabolic plasticity of microalgae species and how that could be adapted in biotechnological settings for sterol production using various culture conditions.Item Open Access Behavior of Short and Slender Concrete Columns Reinforced with GFRP Bars and Square Spirals under Concentric and Eccentric Loads(2025-07-31) Sadat Hosseini, Alireza; Not Applicable; Doctor of Philosophy; Department of Civil and Resource Engineering; Not Applicable; Dr. Martin Noël; Not Applicable; Dr. Fadi Oudah; Dr. George Jarjoura; Dr. Pedram SadeghianWith growing interest in sustainable reinforcement, this thesis investigates the structural behavior of GFRP-reinforced concrete columns, emphasizing the effects of square spirals and ties under concentric and eccentric loading. A combination of experiments, analytical modeling, finite element analysis, and database evaluation is used to address gaps in current design provisions. The experimental program involved 21 column specimens (200 × 200 mm) with slenderness ratios of 20, 40, and 60, subjected to load eccentricities of 0%, 15%, and 30% of the section height. Key variables included spiral pitch, tie spacing and overlap length, and longitudinal reinforcement ratio. Results showed that increasing the tie overlap length by 40% beyond the code minimum shifted the failure mode from brittle, crack-free failure to gradual, post-peak degradation. While square spirals enhanced the stability of short columns under moderate loads, their confinement effectiveness diminished in slender columns and at higher eccentricities. To better understand the role of transverse reinforcement, a novel experimental method was developed by removing the concrete cover, allowing direct observation of failure modes in both longitudinal and transverse GFRP bars. These tests were complemented by 3D finite element (FE) models using concrete damage plasticity (CDP) for concrete and the 3D failure criterion for GFRP. The findings demonstrated that reducing tie spacing and increasing overlap length improved post-peak strength retention. A new deformability index was proposed, and multiple FE modeling approaches were evaluated. Due to the absence of standardized methods for compressive testing of GFRP bars, a novel fixture was developed. A total of 61 specimens with three bar sizes (15M, 20M, 25M) and length-to-diameter ratios of 2, 4, and 6 were tested. The results showed that compressive strength was approximately 86% of tensile strength at a ratio of 2, decreasing with increasing length, while tensile and compressive moduli were nearly identical. Analytical modeling included cross-sectional and second-order analyses. The axial load–moment (N–M) interaction diagrams, developed using equilibrium and strain compatibility, suggest that equivalent stress block approach provides lower-bound estimates; applying a scaling factor of 1.1 could bring the estimates into closer agreement with the analytical results. A second-order analysis using sine-shaped deformation curves yielded a practical slenderness limit of 14 for design. Finally, a comprehensive database of 274 GFRP-RC column tests was compiled to evaluate and refine design code predictions. A new empirical formula was proposed to estimate peak load capacity and effective flexural stiffness, incorporating eccentricity and slenderness effects and addressing limitations of ACI 440.11-22.Item Open Access Living Scaffold: A Framework for Multispecies Architecture(2025-08-01) Foster, Samuel; Not Applicable; Master of Architecture; School of Architecture; Not Applicable; n/a; Not Applicable; Cailen Pybus; Joyce Hwang; James ForrenThe Sandy Lake area of Bedford, Nova Scotia, serves as a vital wildlife corridor, and its health is essential to the region’s ecology. Increasing housing demands, urban sprawl, and its proximity to urban areas render it particularly vulnerable to development. Following a 300-acre clear-cut in 2013, residents began advocating for an expansion of the area’s protected boundaries. This thesis explores how architecture can engage with local ecologies and wildlife as an alternative to conventional conservation methods that minimize human activity and development. Through the design of an ecological learning centre at Sandy Lake, architecture is positioned as a tool to support local biodiversity while encouraging humans to take a more active role in conservation. A living scaffold that benefits both humans and non-human entities contributes to the program’s educational agenda, setting the stage for a citizen science laboratory that fosters the connection between humans and nature.Item Embargo INVESTIGATION OF RING-OPENING COPOLYMERIZATION OF POLY(CYCLOHEXENE SUCCINATE) AND POLY(PROPYLENE SUCCINATE) AS DEGRADABLE BIOMATERIALS THROUGH A DESIGN OF EXPERIMENTS APPROACH(2025-07-31) Murrin, Sara; Not Applicable; Master of Applied Science; School of Biomedical Engineering; Not Applicable; Dr Yunyun Wu; Not Applicable; Dr Mark Filiaggi; Dr Stanislav Sokolenko; Dr Locke Davenport Huyer; Dr Alison ScottDegradable polyester materials are leveraged widely in medicine in resorbable sutures, implantable devices, and drug delivery. Successful materials require precise degradation control: a predictable number-average molecular weight (Mn), narrow polydispersity (PDI), and diverse material properties to expand utility, not easily achieved through well-established synthesis approaches. Ring-opening copolymerization (ROCOP) provides reproducible Mn control, narrow PDI, and expanding monomer diversity. This thesis investigates the utility of ROCOP for degradable polyester biomaterials using design of experiments (DoE). Poly(cyclohexene succinate) (PCS) and poly(propylene succinate) (PPS) were synthesized through a central composite DoE by varying anhydride:epoxide (47/53-53/47), monomer:catalyst (100:1-400:1), time (3-12hr), and temperature (90-110℃). Synthesis factor models explained significant variation for all characterized properties. Base-catalyzed hydrolysis degradation conditions showed significantly higher mass loss in PPS materials compared to PCS, highlighting the monomer selection influence in degradation behaviour. Extracted material property correlations showed mass loss was strongly influenced by Mn and glass transition temperature.Item Open Access Tracing Erasure: Fostering Care and Engagement in Heritage Conservation(2025-07-31) Chadwick, Meghan; Not Applicable; Master of Architecture; School of Architecture; Not Applicable; N/A; Not Applicable; Martha Radice; Rashida Zakia Ng; Diogo BurnayCurrent heritage conservation practices tend to privilege material preservation, often at the expense of intangible, everyday, and erased histories, particularly those of marginalized communities. This thesis reframes conservation through an ethic of care, shifting from a mindset of “protecting from” to one of “caring about.” Guided by core themes of openness, curiosity, and choice, the project positions architecture as a tool to foster engagement, care, and shared authorship of place. Using Halifax as a testing ground, a series of fragmentary, interactive installations are proposed at sites marked by erasure. These architectural interventions function as social prompts, inviting participation, intergenerational dialogue, and storytelling. In this effort of heritage-making, walking is used as both method and metaphor: a slow, attentive practice of experiencing and reflecting. Ultimately, the work proposes a conservation approach that is not static or top-down, but participatory, inclusive, and responsive to the plurality and emergent nature of collective history.Item Open Access From Monument to Living Narrative: Resurrecting the Halifax Memorial Library(2025-07-31) Ziemanski, Jack; Not Applicable; Master of Architecture; School of Architecture; Not Applicable; n/a; Not Applicable; Michael Putman; Rashida Zakia; Diogo BurnayThis thesis proposes the adaptive reuse of the Halifax Memorial Library, transforming it from a static monument into an active civic space. Inspired by Andrew Shanken's The Everyday Life of Memorials, the design explores how memorial sites can be integrate into the city's daily rhythms, moving beyond periodic activation. The core intervention directly embeds the library's layered history and narratives into its architecture, blurring the line between the sacred and the everyday. This approach allows the building to function as a dynamic, lived environment rather than a passive commemorative object. To embody these narratives, the design introduces three archetypal characters: The Archivist, The Pauper and The Steward. Derived from the site's historical traces, these characters serve as narrative agents and spatial guides throughout the building. The result is a library that actively participates in the life of the city, bridging past and present to become a living storyteller.Item Embargo ROLE OF LARGE TUMOR SUPPRESSOR PROTEINS (LATS1/2) IN NEURONAL MATURATION(2025-07-30) Labana, Parabhjot; Not Applicable; Master of Science; Department of Pharmacology; Received; n/a; Not Applicable; George S. Robertson; Kishore Pasumarthi; Jim FawcettThe large tumor suppressor kinases (LATS1/2) are core kinases of the Hippo pathway. Little is known about their expression in the mature CNS. Here we show that Scribble can precipitate LATS2 protein from rat adult hippocampal lysate and that phosphorylated LATS (pLATS) and Scribble localize to the axon initiation segment (AIS) in hippocampal neurons. Using STED microscopy, we find that both Scribble and pLATS form distinct puncta with the Scribble puncta being190nm apart, similar to the pLATS puncta. Overexpression of myc-LATS2 and using a novel CRISPR dependent approach to label endogenous LATS2 with GFP, reveal that LATS2 is enriched in dendritic spines. Next, we developed a conditional approach to reduce LATS proteins in post mitotic neurons – this was unsuccessful. Nonetheless, this work identifies that LATS2 is expressed in hippocampal synapses, implicating it as an important kinase in learning and memory.Item Open Access Antigen-Adaptive NK Cell Memory In The Absence Of Functional TCR Genes(2025-07-25) Bryan, Safyha; Not Applicable; Master of Science; Department of Microbiology & Immunology; Received; Dr. Jeanette Boudreau; Yes; Dr. Jean Marshall; Dr. Paola Marcato; Dr. Andrew MakrigiannisNatural killer (NK) cells are among the founding members of innate lymphoid cells, specialized in the recognition and elimination of virally infected cells, tumour cells, and abnormal cells. Recent research studies have uncovered that NK cells also exhibit adaptive immune features similar to T and B cells, which holds promise for using the NK cell memory for the development of new cancer and viral immunotherapies. Research in our lab demonstrated that NK cells can elicit immunological memory in Rag1-/- mice, which are devoid of the adaptive T cells and B cells. However, there remains a need to explore whether this phenomenon persists in the complete absence of TCR genes. The ability of NK cells to mediate adaptive responses was evaluated by studying the contact hypersensitivity ear swelling response to chemical haptens and peptides in TCR-β-/-δ-/- mice. This was done in conjunction with NK cell depletion via anti-NK1.1, Ly49C/I+ NK cell depletion via anti-Ly49C/I, and B cell depletion via anti-CD20. In the absence of NK cells, specifically Ly49C/I+ NK cells, TCR-β-/-δ-/- mice were unable to exhibit immunological memory responses. Furthermore, depleting B cells did not impact TCR-β-/-δ-/- mice’s ability to exhibit adaptive responses. It was essential that mice be sensitized and challenged with the same hapten or peptide in order for NK cell memory responses to be observed. These results show memory responses can be attributed to NK cells in the absence of TCR genes and is antigen-specific. This study shows that NK cells are a physiologically relevant contributor to the adaptive immune response as immunological memory can be observed in the absence of TCR genes. A better understanding of the adaptive NK cell responses elicited in these studies can be exploited in therapeutic and prophylactic treatments of cancer and viral infections.Item Open Access NUMERICAL INVESTIGATION OF SURFACE SLIP ON TURBULENCE PROPAGATION AROUND THE TIP SECTION OF NREL 5MW OFFSHORE WIND TURBINE(2025-07-29) Quayson-Sackey, Emmanuel; Not Applicable; Master of Applied Science; Department of Mechanical Engineering; Not Applicable; n/a; Yes; Mohammad Saeedi; Adam Donaldson; Baafour Nyantekyi-KwakyeThis study investigates the effect of surface slip on unsteady vortex dynamics around a NACA 64-618 airfoil at a Reynolds number of 1.3 × 10⁶ and angle of attack of 12°. A Navier-slip boundary condition, mimicking a superhydrophobic coating, was applied to evaluate its influence on turbulent flow behavior. Four slip lengths (Ls = 100 µm, 140 µm, 185 µm, and 400 µm) and a baseline no-slip case were analyzed. Instantaneous and mean velocity fields, frequency spectra, and proper orthogonal decomposition (POD) were used to characterize the flow. Slip was found to suppress trailing-edge separation bubbles and enhance wake flow acceleration. Shear-layer instability intensified, leading to early vortex roll-up. Frequency analysis showed a shift to lower dominant frequencies, especially for Ls = 400 µm, indicating small-scale vortex pairing. POD results revealed increased turbulent kinetic energy in the wake, concentrated within dominant mode pairs due to surface slip.Item Open Access Reconnecting Roots: Food as a Bridge to Human, Social, and Cultural Capital(2025-07-29) Gaulton, Cody; Not Applicable; Master of Architecture; School of Architecture; Not Applicable; n/a; Not Applicable; Eric Stotts; Rashida Zaika Ng; Diogo BurnayThe industrial food system has disconnected us from our relationship with food, from seed to compost. Threatening entire ecosystems, fostering an obesity epidemic, and socially isolating consumers from food processes, corporations have no empathy for health, culture, or the environment. Through mapping, case study analysis, and demographic analysis, the aim of this thesis is to demonstrate how the sharing of food, supported by Building Integrated Agriculture (BIA) can create healthy sustainable communities within an education-based cultural food hub in Halifax, NS that reconnects us to our food. The project will advocate the importance of growing, processing, cooking, and eating food with others and the cultural, environmental and health benefits from doing so. Placing emphasis on moving away from dependence on an industrial food system and more reliance on local food production and education that will build resilience and food security, through the imparting of food knowledge to the next generation.Item Open Access Downstream effects of brown seaweed supplementation in beef cattle diets on greenhouse gas emissions and coprophagous beetles(2025-07-28) Bennett, Samantha; Not Applicable; Master of Science; Faculty of Agriculture; Not Applicable; n/a; Not Applicable; Dr. Ghader Manafiazar; Dr. Rhea Lumactud; Dr. Paul Manning; Dr. David BurtonThe Canadian livestock sector is a significant source of greenhouse gas (GHG) emissions. To reduce enteric methane emissions, the sector has started using mitigation strategies, such as dietary interventions. While studies have shown that supplementing beef cattle diets with brown seaweed can reduce enteric methane emissions, the downstream effects of dietary supplementation remain unclear. This thesis explores the downstream effects of supplementing beef cattle diets with brown seaweed on dung and beetle-mediated GHG emissions, as well as on coprophagous beetles’ reproductive success and resource use and selection. To assess these effects, dung was collected from beef cattle assigned to four treatment groups based on the dietary level of brown seaweed inclusion (i.e. 0%, 0.5%, 1%, 2%). Laboratory-based experiments revealed that dietary supplementation, at a rate of 2% of dry matter intake (DMI), reduced dung CH₄ emissions by 49% and CO₂ emissions by 26%, resulting in a 30% reduction in dung CO₂e emissions. While dietary supplementation with brown seaweed reduced dung’s baseline CH₄ emissions, the relative beetle-mediated reductions remained identical. This suggests that supplementing beef cattle diets with brown seaweed had no effect on C. erraticus’ CH₄ mitigation potential, as the smaller absolute effects noted in supplemented dung samples were caused by lower initial CH₄ emissions. Additionally, dietary supplementation had no effect on beetle-mediated CO₂e emissions. Through a combination of field- and laboratory-based experiments, this project found that the inclusion of brown seaweed in beef cattle diets reduced both Onthophagus nuchiocornis’ resource use for brood ball production and the proportion of major males in beetle offspring. These results suggest that dietary supplementation reduced dung quality. However, when evaluated under field conditions, coprophagous beetles’ resource selection was not affected by dietary supplementation. Across studies, there is a lack of consensus on the impact of dung beetles on GHG emissions from livestock dung. Using a series of laboratory-based experiments, this work shows that methodological decisions strongly influence dung and beetle-mediated GHG emissions. For example, the homogenization of dung prior to GHG sampling, dung’s surface-area-to-volume ratio, and dung mass all influence beetle-mediated GHG emissions from dung. Overall, results from this research reveal the downstream effects of supplementing beef cattle diets with brown seaweed on dung beetle ecology and dung GHG emissions. These results highlight the need to assess the downstream effects of management interventions when trying to determine their ability to improve the environmental sustainability of livestock production.Item Open Access 3D MICROSTRUCTURED POLYMERS FOR TRIBOELECTRIC NANOGENERATORS(2025-07-28) Sunny-Ekhalume, Ebubechukwu; Not Applicable; Master of Applied Science; Department of Electrical & Computer Engineering; Not Applicable; n/a; Not Applicable; Haned Aly; Azadeh Kermanshahi-Pour; Ghada KoleilatThe demand for sustainable and decentralized energy solutions has intensified research into Triboelectric Nanogenerators (TENGs). This thesis explores the development of microstructured TENGs using 3D printing technologies, with a focus on the fabrication of triboelectric polymers. It also investigates the integration of Liquid Crystal Display (LCD)-based additive manufacturing with electrospinning to create flexible, microstructured TENG prototypes. Microstructuring in the form of different geometries was achieved and compared to flat counterparts to assess electrical output. Furthermore, this study also evaluated different parameters such as flow rate, tip-to-collector distance, and base-height ratios, and their impact on fiber uniformity and surface area. Experimental results showed that structured surfaces, especially pyramidal geometries, significantly enhanced charge generation and energy conversion efficiency compared to unstructured layers. The performance limitations and resolution constraints of commercial LCD printers were analyzed. This research highlights the feasibility and promises of combining microstructuring and 3D printing in advancing TENG.Item Embargo IMPROVING DISEASE MANAGEMENT ON HONEYCRISP APPLES IN MARITIME CANADA(2025-07-28) McLaughlin, Michael; Not Applicable; Doctor of Philosophy; Department of Plant, Food and Environmental Sciences; Not Applicable; Dr. Srđan Aćimović; Yes; Dr. Lord Abbey; Dr. Svetlana Yurgel; Dr. Morgan Langille; Dr. Shawkat Ali; Dr. Balakrishnan PrithivirajFor decades, growers have relied on chemical eradicative fungicides as an efficient means to control fungal diseases in apple fruit. However, increasing concerns over fungicide resistance, along with the environmental and human-health risk associated with these products have led to increased restrictions on their use. To maintain effective disease management, chemical fungicide must therefore be complemented by up-to-date information on local pathogen populations as well as eco-friendly alternatives, such as the use of plant defence elicitors (PDEs) or manipulation of the host microbiome. This thesis aimed to (i) characterize the Colletotrichum species responsible for apple bitter rot in Nova Scotia, (ii) describe the microbiome of ‘Honeycrisp’ apple fruit, and (iii) evaluate the use of salicylic acid (SA) as a PDE in an integrated disease management program. In the first study, multi-locus sequencing revealed three distinct species within the Colletotrichum acutatum species complex (CASC) affecting apple fruit in Nova Scotia: C. fioriniae, C. salicis and C. nymphaeae, and compared their relative virulence and fungicide sensitivities. The second and third studies investigated the fungal and bacterial microbial communities associated with ‘Honeycrisp’ fruit in Maritime Canada, respectively. Abiotic and biotic factors such as the environmental conditions of the growing season, management system (organic vs conventional), geographical location and the specific tissue-microhabitat were found to significantly influence the structure and diversity of apple fruit microbial communities. These findings highlight major challenges for disease control through microbiome manipulation. In the fourth study, the impact of non-eradicative treatments such as PDEs was compared to that of eradicative chemical treatments on the fungal communities of apple fruit. Chemical treatments were shown to significantly disrupt microbial network complexity, potentially leading to reduced network stability and increased vulnerability to infection. Finally, in the fifth study, the efficacy of an integrated spray program including SA was assessed. The integration of SA into a conventional fungicides program allowed a 27% reduction in fungicide use without compromising disease control on ‘Honeycrisp’ leaves during the growing season or on apple fruit at harvest and post-storage.