Host Choice Selection in The Aster Yellows Pathosystem

The abstract of this item is unavailable due to an embargo

Surface Sensitive Studies of Interfacial Water Structure in Saturated Aqueous Solution of NaClO4

Over the past years, it has been found that understanding the metal/water interaction plays a vital role in multidisciplinary fields ranging from heterogeneous catalysis and electrocatalysis to water in salt systems for advancing commercial battery technologies. It is also believed that the main properties of the WiS (water in salt) electrolytes are mainly linked to the chemical and physical properties of the interfaces between the water molecules in the WiS system and the metal electrode. This research focuses on conducting surface-sensitive studies on interfacial water in WiS systems, and the main approach of these experiments is to investigate water interaction and orientation as a function of the surface charge and NaClO4 concentration at the water/Gold electrode interface. In pursuit of this objective, ATR (attenuated total reflectance) was utilized to gain knowledge about the structure of water molecules in the solution as the concentration of NaClO4 increasing Additionally, ATR technique can provide an insight into the hydrogen bonding in the water in salt system. Utilizing ATR-SEIRAS (Attenuated Total Reflectance Surface-Enhanced Infrared Absorption Spectroscopy) in the subsequent phase of the project could potentially demonstrate valuable data about potential-dependent water adsorption as well as changes in hydrogen network strength in the double layer region as a function of the applied potential. The outcomes from the ATRSEIRAS technique provided a representation of the possible orientation of water molecules in different potentials. The hydrogen-oriented upward arrangement for water molecules is proposed in positive potentials, while in negative potentials, the hydrogen atoms of water are closer to the surface. Subsequently, the hydrogen network is stronger on the positively charged surface

Exploring the Stability of Self-Compassion, Self-Criticism, and Grit in Professional Triathletes Within Training

Professional triathletes need to navigate a fine line of training for three sports along with the mental and physical challenges of trying to meet standards of performance in order to be successful. The purpose of my research was to observe, through an exploratory through a single case design (SCD) study, whether self-criticism, self-compassion, and grit fluctuate for professional triathletes over a 3-week training period in which they are trying to achieve performance standards. Two professional long distance triathletes completed pre- and post-test measures of self-compassion, along with daily reports of these same measures. A visual analysis of daily measures was performed, recealing a general lack of stability in the variables examined both within and across participants. While one of the two athletes did not meet standards on two consecutive days as a naturally occurring intervention point, differences in stability before and after not meeting standards were challenging to interpret and demonstrate the complexity in athletes’ experiences related to trying to achieve performance standards. It remains for future research to determine whether the daily fluctuations I observed are representative of “true” daily changes in the constructs themselves or a result of measurement error associated with using single-time measures (or a combination of both)

Voices for Change: Qualitative Content Analysis of Environmental Activists with Autism in the News

Peer ReviewedThree activists have played key roles in recent climate activism in the UK: Greta Thunberg, Dara McAnulty, and Chris Packham. Through qualitative content analysis of popular news coverage, this study explores the messages conveyed about these activists and the social inequities prevalent in media portrayals of activism more broadly. The analysis revealed that while there was content explaining and defining the causes championed by these activists, it was often overshadowed by subject-centric portrayals. The news coverage tended to emphasize the agency and influence of these individuals, while also placing undue focus on their various identity constructs. The coverage also adopted personalized and sensationalized writing strategies. Although this news coverage offered a more inclusive representation of activists in terms of disability, age, and gender, it simultaneously reinforced stereotypes, prejudice, and the authority of White, middle- to upper-class activists from the global North. These findings highlight tensions between reinforcing and challenging the privileged few who are typically allowed to represent and capture public attention and action on pressing issues

IMMUNOHISTOCHEMISTRY AS A TOOL FOR MECHANISTIC STUDIES OF RADIOIMMUNOTHERAPY OF OSTEOSARCOMA

Osteosarcoma (OS), characterised by the direct formation of immature bone or osteoid tissue by tumor cells, is a primary malignant bone cancer affecting humans and canines. This study explores the potential of Targeted Radionuclide Therapy (TRT), specifically Radioimmunotherapy (RIT), as a novel treatment approach for OS. RIT utilises antibody molecules to deliver radiation to tumor cells, with promising applications in treating metastatic disorders. Notably, the cation-independent mannose-6-phosphate/insulin-like growth factor-2 receptor (IGF2R) has been identified as a viable therapeutic target for RIT in OS due to its high expression in tumor cells. To investigate the impact of RIT on the OS tumor microenvironment (TME), we conducted Immunohistochemistry (IHC) analyses. The results revealed a reduction in IGF2R-positive cells, OS stem cells, and pro-tumorigenic M2 macrophages following RIT. Notably, RIT showed diverse effects on natural killer (NK) cells and M1 macrophages. Specifically, RIT employed two radioisotopes with different decay schemes: the alpha-emitting Actinium-225 (225Ac) and the betaemitting Lutetium-177 (177Lu). The alpha-emitting 225Ac led to a decrease in NK cell numbers; at the same time, the beta-emitting 177Lu increased NK cell populations, potentially indicating a stimulating effect. Likewise, the increase in M1 macrophages numbers in Gracie (canine OS cell line) and the decrease in M1 macrophages numbers in OS33 (human OS cell line) post-RIT suggests the highly dynamic and variable behaviour of TME. This research underscores the potential of RIT in modulating the TME and offers new insights into its efficacy against OS. Understanding the intricate relationship between RIT, the choice of a radioisotope, and TME is essential for refining treatment strategies and harnessing the immune system's capabilities. This study paves the way for more personalised and effective therapeutic approaches, which could benefit patients facing this challenging cancer

INFLUENCE OF MICROBIAL SULFATE REDUCTION ON PORE-WATER CHEMISTRY IN OIL SANDS FROTH TREATMENT TAILINGS

Oxidative weathering of froth treatment tailings (FTT) at oil sands mines in Northern Alberta has the potential to generate acidic and metalliferous porewater. Residual bitumen and light hydrocarbons in FTT support growth of a diverse range of microbes, including those capable of dissimilatory sulfate reduction (DSR). This biogeochemical process can be effective in removing sulfide-mineral oxidation products such as Fe, SO4, and trace elements including As, Co, Cu, Ni, Se, and Zn through sulfate reduction and sulfide mineral precipitation under anoxic conditions. While previous experiments that have stimulated sulfidogenesis through organic carbon amendments effectively decreased the mass flux of sulfide-mineral oxidation products in mining environments, the extent of this process and its ability to attenuate sulfide-mineral oxidation products in FTT supported by residual hydrocarbons is unknown. The objective of this thesis is to assess the impact of microbial sulfate reduction on FTT pore-water geochemistry and to determine the potential extent to which this process may be supported by residual hydrocarbons within the tailings deposit. Laboratory experiments were designed to examine the influence of sulfidogenesis on pore-water chemistry and to constrain rates of sulfate reduction, while assessing the capacity for metal(loid) removal due to this process. Through batch and column experiments sulfate reduction was found to contribute to metal(loid) and sulfate removal, as well as pH buffering and H2S generation. Removal of As, Co, Ni, and Se exceeded 90% in simulated porewater over a pH range of 5 – 8. Removal of Fe was minimal below pH 7, but exceeded 95% in solutions above pH 7 with long residence times. Zn removal was influenced by ∑S(-II)(aq) concentrations, with increased Zn removal seen at lower ∑S(-II)(aq) concentrations. Sulfur isotope samples taken during the batch experiment show an increase in 34S-SO4 with decreasing SO4(aq) concentrations over time, showing ongoing microbial sulfate reduction during the experiment. A mass-based approach to determine sulfate removal found sulfur removal rates remained constant around 1.5 μmol d-1 g-1 when solutions were not saturated with respect to gypsum. Residence time and pH were major influences on the effectiveness of sulfate reduction, with enhanced metal(loid) removal occurring with longer residence times at circumneutral pH. These results show the pool of organic carbon in FTT deposits is capable of supporting dissimilatory sulfate reduction and this process can decrease mass fluxes of sulfide-mineral oxidation products in FTT porewater

NUCLEAR FACTOR ERYTHROID 2 RELATED FACTOR-1 (NRF1) MEDIATES CELASTROL-INDUCED GENE REGULATION, DEPENDING ON ITS HETERODIMERIC INTERACTIONS

Oxidative stress has been recognized as critical in human aging and the progression of many chronic diseases, including cancer. Cells undergo oxidative stress when the overproduction of reactive oxygen species (ROS) within the cell outweighs its antioxidant defenses. As a defense mechanism, a series of cytoprotective genes is initiated and regulated by various transcription factors in order to minimize oxidative damage to the cell. NF-E2-related factor 1 (NRF1) is a Cap'N'Collar (CNC) transcription factor family member that plays a major role in regulating genes involved in defense against cell stress and damage. For example, NRF1 is a vital regulator of antioxidant and proteasome genes to counteract ROS and impaired protein homeostasis. Upon stress caused by impaired protein turnover, NRF1 undergoes endoplasmic reticulum to nuclear translocation and binds antioxidant response elements (ARE) located in close proximity to stress defense genes throughout the genome. The result is altered transcription of the associated gene. While this general concept has been established, the mechanism by which NRF1 is processed, selected for nuclear translocation rather than degradation, and the role of post-translational modifications is not understood. Moreover, previous studies show NRF1 must form a heterodimer with other transcription factors such as small musculoaponeurotic fibrosarcoma oncogene homolog (MAF) proteins to bind AREs and regulate gene transcription. The mechanism underlying NRF1 heterodimer formation and ARE binding and whether distinct heterodimers regulate distinct genes is unclear. I hypothesize NRF1 regulates proteasome and oxidative stress defense via specific heterodimer interactions. In this thesis, I describe our identification of the nutraceutical celastrol as a stimulant for NRF1’s transcriptional activity. For centuries, celastrol has been used to treat inflammatory and chronic diseases and more recently found to influence a multitude of stress pathways and suppress chymotrypsin-like activity of the proteasome. I then proceeded to use celastrol to investigate my hypothesis. Using cultured Hep3B cells, I show celastrol elicits dose-dependent inhibition of the proteasome and this increases the level of a cleaved NRF1 protein product known to regulate transcription. Using clustered regularly interspaced short palindromic repeats (CRISPR)/cas9 based technology to produce NRF1 loss-of-function cells, I show celastrol induces transcription of proteasome and oxidative stress defense genes in an NRF1-dependent manner. Likewise, quantitative polymerase chain reaction measurement of immunoprecipitated chromatin revealed that NRF1 binds to AREs in stress defense genes GCLC, GCLM, HO1, NQO1A in a manner that corresponds with transcription regulatory profiles. Moreover, ablation of NRF1 heterodimers MAFG, MAFK, or MAFF resulted in refractory responses to celastrol that partially and nonredundantly matched NRF1 deficiency. Collectively, results of my research support a model whereby NRF1 heterodimerization with MAFK regulates one gene sub-set or program, whereas heterodimerization with MAFG or MAFF regulates another one. In other words, specific heterodimeric interactions coordinately stimulate or repress the transcription of a group of target genes

Microbial Pretreatment of Camelina Straw and Switchgrass for the Production of Solid Biofuel Pellets and Bioethanol

The abstract of this item is unavailable due to an embargo

BALANCING OTIPEMISIWAK AND WAHKOHTOWIN: MÉTIS WOMEN AT ST. FRANÇOIS XAVIER, MANITOBA, 1790-1840

Centering the principles of otipemisiwak and wahkohtowin, this thesis examines the role of Métis women in the development of the community of St. François Xavier. While recent historiographical shifts have emphasized community-engaged histories and women’s voices, the role of Métis women within the Red River region during the first half of the nineteenth century remains largely underexplored. This research addresses this gap by highlighting how women were instrumental in shaping the community’s identity during the period of 1790-1840. Utilizing the worldviews of otipemisiwak and wahkohtowin offers a nuanced understanding of how Métis women embedded these concepts into the collective identity, asserting their independence whilst nurturing kinship. Ultimately, this thesis sheds light on the enduring significance of Métis women’s leadership and their vital role in shaping Métis identity, offering a deeper understanding of the community of St. François Xavier as a whole

The Journey of a kêhtê-aya (elder): kiskisi sôhkisiwin, tâpôkêyimoh, sôhkitêhê, nâkatohkê: Memorize the Strength, Have Faith, Have a Strong Heart, Pay Attention

I am from Onion Lake Cree Nation. I am a nêhiyaw-iskwêw (Cree woman). My first language is nêhiyawêwin/Cree. I lived with my great-grandparents until I started residential school in 1956. My PhD research is based on my belief in healing, reconciling, and reclaiming Indigenous education to benefit students, families, and communities. There is a critical need to explore the role of Elders in schools. How are they used and positioned, by whom, and why? How can the education system move away from inviting Elders to check box-type activities and progress to having Elders acknowledged as having integral and continuous roles in schools where their knowledge is central to shaping and informing the unfolding curriculum being lived out with children and families? These are the questions that you will find explored and discussed in the videos that comprise the core of this dissertation, focused on discussions of the commodification and changing role of Elders; cultural trauma; artivism and reparation; and healing, reconciling, and reclaiming Indigenous education for the benefit of students, families, and communities. As a methodological approach, I followed the teachings shared by my mother, who is central to this work. What I did, and how and when I did it, was led by following protocol, prayer/prayer songs, and the offering of tobacco; it guided every aspect of my journey. My daily work began with smudging and prayers, the tobacco led me to invite thought leaders for the four conversations, it inspired my bookwork, and it guided my thought processes and decision making throughout my doctoral journey. Each conversation began with smudging, prayer/prayer song, and the offering of protocol to the thought leaders so that our conversation would unfold in a good way, with open eyes, ears, minds, and hearts. From January through December 2022, I spent one year in the field as an Elder/kêhtê- aya. I kept a journal of my Elder/Knowledge/Keeper requests and recorded my research to prepare for the commitment and my experience. This fieldwork was integral to planning and preparing for four video conversations with invited thought leaders. To fully understand the work asked of Elders it was necessary for me to immerse myself in the work of an Elder/Knowledge Keeper. I made a commitment to accept up to three protocol requests per week. Topics were varied from sharing opening prayers and comments, presenting on residential school history or treaties, and sitting on cultural advisory committees. To prompt each conversation, I created a bookwork arising out of the conceptualization that became the focus. A bookwork is a non-book that relies on the viewer’s interaction with the object to make meaning. Each installation is a narrative that tells a story. Artists’ books, or bookworks, first emerged in the 1960s and 1970s as an expression of social and political activism, a way to “talk back” to mass production and mass media. Creating the bookworks required extensive research on the focus topic, including consulting with artists, art professors, curators and visiting art exhibits. Each bookwork took six months to a year to complete. My video dissertation is a compilation of 10 videos: my introduction to the research journey, the four core conversations with thought leaders conducted in a talking circle format, each with a separate video introduction by me, and a culminating video that shares my research reflections. The videos have an accompanying transcript, in which I included the spoken Cree and I translated the Cree language into English. My doctoral work also includes an eleventh video which captures the gallery show I arranged and hosted at AKA Gallery in the Saskatoon community to profile the four bookworks and showcase the video dissertation. In summary, the videos, the transcripts, the bookworks, and the gallery show are all integral pieces to my doctoral dissertation. Further, I have included a glossary of terms to accompany the viewing/reading of the videos and transcripts, and a bibliography for those individuals who want to pursue aspects of this work more deeply or for purposes that move forward their own work and thinking