Arts and Science, Faculty of
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- ItemExploring sulfate cycling in a mineral-soil wetland restored with wastewater(Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, 2024) Denny, Mariya; University of Lethbridge. Faculty of Arts and Science; Bogard, Matthew J.Sulfate (SO42-) pollution is contributing to the salinization of surface waters worldwide. Wetlands are natural filters on the landscape that remediate surface water by retaining and processing pollutants. However, the capacity for wetlands to process excess SO42- from wastewater is poorly understood, especially for natural (as opposed to constructed) wetlands. Here, I explore the SO42- remediation capacity of Frank Lake, a restored, multi-basin wetland complex in southern Alberta, Canada, that is used to treat effluent from municipal and beef slaughterhouse sources. Using a combination of approaches, I show that there was limited SO42- processing throughout the wetland. Mass balances constructed for two distinct hydrologic periods showed that Frank Lake shifted from a SO42- source during wet years (2013 - 2015) to a sink during drought years (2021 - 2022). Yet I found little evidence of active SO42- processing in surveys conducted during drought years. SO42- remained the dominant form of sulfur (S) among all three basins (>95% of total S), implying little net change in the S pool. Similarly, dual stable isotope (34S and 18O) analysis showed limited isotopic enrichment among wetland basins, implying limited transformation of SO42- via microbial reduction. Sediment incubations confirmed the patterns observed with stable isotopes, showing little net removal of SO42- throughout the wetland. The preferential reduction of nitrate (NO3-) and other more energetically favourable constituents of the effluent may restrict the extent of microbial SO42- reduction throughout Frank Lake. The limited extent of emergent and submerged vegetation may also limit SO42- uptake by plants. Given the limited SO42- processing in Frank Lake, and the headwater position of this wetland complex in the broader aquatic network, my work provides context for previous reports of increasing salt concentrations documented in rivers of the South Saskatchewan River watershed.
- ItemInvestigating the structure-function relationship of anti-mitotic natural products in Canadian prairie plants(Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, 2024) Healy Knibb, Shannon M.; University of Lethbridge. Faculty of Arts and Science; Golsteyn, RoyThis thesis investigates Canadian prairie plants as sources of natural product compounds capable of inhibiting human cell division. Natural products present an opportunity to identify novel anti-mitotic compounds to address the lack of known inhibitors for many mitotic regulatory proteins. By biology-guided fractionation, we purified the natural products anemonin from Pulsatilla nuttalliana and (+)-6-tuliposide A from Erythronium grandiflorum, and this is the first report of their anti-mitotic activities. We then conducted a comparative study between pulchelloid A (from Gaillardia aristata), anemonin and (+)-6-tuliposide A, and identified unique mitotic arrest profiles, suggesting distinct protein targets and mechanisms of action consistent with the widespread relationship between structure and function in biology. The discovery of natural product inhibitors from Canadian prairie plant species holds tremendous potential for advancing our understanding of mitotic regulation and contributes to the development of targeted treatments for precision medicine.
- ItemAnxiety behaviour and inflammatory markers in c57/bl6j mice are enhanced after a chronic dose of DSS colitis during contextual fear conditioning(Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience, 2024) Beekman, Kaylen A; University of Lethbridge. Faculty of Arts and Science; Gruber, Aaron J.This thesis describes how induced gut inflammation induces brain inflammation via the brain-gut axis. It further shows that mice with elevated gut inflammation display post-shock behavioural correlates of anxiety for longer duration than mice that do not have gut inflammation. The gut-inflamed mice also show a reduced ability to recover from fearful experiences and higher relative quantities of inflammatory markers in the nucleus accumbens. Mice receiving both gut inflammation and psilocybin show reduced anxiety behaviour and lower relative quantities of inflammatory markers in the nucleus accumbens. This thesis demonstrates that induced gut inflammation drives increased inflammation in the nucleus accumbens and results in increased measures of anxiety in conditioned and unconditioned behavioural tasks. Some outcomes were ameliorated by the addition of a single dose of psilocybin. Overall, these data improve understanding of potential mechanisms by which anxiety may be produced and treated. Research was completed under protocol number 2018.
- ItemA survey of Büthe's method for estimating prime counting functions(Lethbridge, Alta. : University of Lethbridge, Dept. of Mathematics and Computer Science, 2024) Bhattacharjee, Sreerupa; University of Lethbridge. Faculty of Arts and Sciences; Ng, NathanThis thesis provides explicit bounds for the Chebyshev prime counting function ψ(x). This thesis aims to produce a detailed survey of the first part (from page 2483 to page 2494) of the paper, ‘Estimating π(x) and Related Functions Under Partial RH Assumptions’ by Jan B ̈uthe published in 2016. His article provides the best-known bounds for ψ(x) for x ≤ e3000 using the Fourier Transform of the Logan Function, assuming the Riemann Hypothesis to be valid for all zeroes of the zeta function with ℑ(ρ) ∈ (0, T ] for a specific T. The main theorem in B ̈uthe’s paper gives a bound for |ψ(x) − x| using an equation with three major terms E1, E2 and E3 and provides bounds for each of these terms individually. The necessary lemmas, propositions and their proofs required to prove the main theorem are scattered throughout various papers such as [7], [8], [10], [18], and [6]. In this thesis, we have accumulated all these results, verified their proofs, and included various missing details. Several of the arguments in the original paper have been reworked, and necessary corrections, such as rectifying the error terms E2 and E3 in the main theorem, and other minor amendments have been made with the goal of turning this thesis into a self-contained research exposition of B ̈uthe’s work in [7].
- ItemPatterns of sedentary time and physical activity in older adults: do sex and gender matter?(Lethbridge, Alta. : University of Lethbridge, Dept. of Kinesiology and Physical Education, 2024) Zdjelar, Milena; University of Lethbridge. Faculty of Arts and Science; Copeland, JenniferProlonged sedentary time and inadequate physical activity are detrimental to the health of older adults. Sex and gender may influence health and movement behaviours that impact health. The purpose of this research was to scope the available literature on sex and gender in sedentary behaviour and then explore the relationship between biological sex and gender traits on movement behaviour patterns among older adults. In the scoping review, 210 articles were screened and 41 were identified that examined sex and/or gender in relation to sedentary behaviour in older adults. Almost all studies used sex- and/or gender-related terms interchangeably. Of the 41 articles, 28 studies suggested the division of household labour is the main explanation for any observed sex and/or gender differences in sedentary behaviour. The remaining 13 studies identified other factors that may influence this relationship, like social support, access to transportation, and area-level crime incidence. To further explore the relationship, observational data from 72 healthy older adults (80.1 ± 9.4 years) were examined. Movement behaviours were assessed using ActivPAL4™ inclinometers and participants completed the 30-Item Bem Sex-Role Inventory to assess masculine and feminine traits. There were no statistically significant associations between movement behaviour variables, sex, and masculine and feminine scores. This exploratory study demonstrates a need for consistent use of sex and gender terminology and better tools to assess gender. A more comprehensive understanding of the complexity of sex and gender in relation to health is needed to enable the creation of tailored movement behaviour interventions for the aging population.