StFX Scholar (St. Francis Xavier University)
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Explaining body composition after bariatric surgery using accelerometry
No full textObesity is a multifaceted malady encompassing genetic, behavioural, socioeconomic, and environmental determinants, which significantly exacerbates health risks and is implicated in augmented morbidity and mortality. Bariatric surgery emerges as a potent intervention for severe obesity, effectuating remarkable weight reduction. Nonetheless, post-surgical weight recidivism remains a daunting impediment because the challenge of maintaining long-term weight loss after initial significant reduction, particularly following bariatric surgery. This investigation delves into the kinematic patterns of 59 individuals, aged 19 to 70 (average age: 49.5 years with standard deviation (SD) of 9.2 years), with a mean time span of 8.6 years (SD of 3.7) years post-bariatric surgery, deploying wearable accelerometry to discern the intricate correlations among movement behaviours, body composition, and weight regain. Through the integration of cutting-edge machine learning algorithms, an intelligent prognostic system was devised to extrapolate total body fat percentage and visceral adiposity. The study evinced that Multivariate Adaptive Regression Splines (MARS) and Gradient Boosting models exhibited superlative performance, with MARS achieving a Mean Absolute Error (MAE) of 4.07 and Root Mean Square Error (RMSE) of 4.80 for fat percentage prediction, and Gradient Boosting obtaining an MAE of 0.71 and RMSE of 0.75 for visceral fat prediction
Investigation of the aggregate behaviour of monomeric and dimeric surfactants by calorimetry and NMR spectroscopy
No full textSurfactants are amphiphilic molecules composed of a hydrophobic and hydrophilic parts. The growth of demand for surfactants is due to their wide range of usage from household detergents and personal care products such as cleaners to industrial applications such as agricultural chemicals. This thesis will deal with the investigation of a class of surfactants known as gemini (or dimeric surfactants) and related amphiphiles. Gemini surfactants are multi-functional surfactants that can best be described as two single chained, single-headed surfactants joined together by a linker group (the spacer group) near the point of attachment of the hydrophilic heads. Gemini (or dimeric) surfactants possess many superior properties versus conventional monomeric surfactants such as reduced critical micelle concentrations (or CMC values), lower surface tensions, and improved solubilization capacities. A significant amount of literature exists on the synthesis and micellar properties of gemini amphiphiles; however, detailed structure -performance relationships and assessments of the thermodynamic of self-assembly as a function of amphiphile structure are lacking. In this thesis, we will measure the thermodynamics of micellization of both symmetric and dissymmetric gemini amphiphiles as a function of temperature and examine how the thermodynamics of self-assembly vary with temperature and amphiphile architecture. We will also examine the cmc values of mixed micelles consisting of gemini surfactants of different architectures with commercially important zwitterionic surfactants. Although the CMCs can be determined using many different techniques/experimental approaches (e.g., tensiometric, electrochemical, or conductivity), this thesis will focus on the use of DOSY-nmr to examine the cmc values of mixed surfactants system and to determine both the micellar and the monomeric compositions of the mixed aggregates. Finally, carbon-13 chemical shifts will be used to examine the packing of dimeric surfactants in micelles as a function of the surfactant architecture. All these results will be used to discuss how subtle changes in the amphiphile architecture can lead to significant differences in a) the way dimeric surfactants self-assemble into aggregates of various shapes; and b) how they interact with other amphiphiles in the formation of mixed aggregates
Exploring how Mi'kmaq women of Ktaqmkuk are building a sense of community: A case study
No full textQalipu First Nation was established as a landless Mi’kmaq First Nation band in 2011 and represents 67 traditional Mi’kmaq communities located in the western and central regions of the island of Newfoundland, or “Ktaqmkuk” in the Mi’kmaq language (Matthews & Robinson, 2018). The term Mi’kmaq is the plural form of the word Mi’kmaw and refers to the entire nation (Sable & Francis, 2012). The band was formed after decades of activism by Mi’kmaq people of the province who sought formal recognition by the Government of Canada. This study sought to identify the ways in which Mi’kmaq women leaders of Qalipu First Nation identify a sense of community and are contributing to their communities through their volunteer work, considering the widespread membership. To accomplish this, an exploratory case study was conducted involving four Mi’kmaq women leaders of Qalipu First Nation. The in-depth interviews highlighted their approach to leadership and how their identity has been shaped by their leadership and culture. This study identified a positive sense of community within the traditional Mi’kmaq communities, however, when it came to the overall community of Qalipu First Nation the participants did not translate the same feelings. The status situation of Qalipu First Nation has negatively affected members and was noted to have an impact on the women’s leadership as well as overall feelings of the membership towards the band. The principles of asset-based community development were present throughout the interviews with suggestions that Qalipu First Nation focus on building its own source revenue to help meet the needs of the membership without relying on outside funding
Physical Literacy in Children who Participate in Elite Sport or Recreational Activities
No full textIntroduction: Physical literacy is described as the physical competence, confidence, motivation, and knowledge and understanding to value and engage in a physically active lifestyle. Children in elite sport may not have the same opportunity to become physically literate as children who participate in a highly active afterschool physical activity program as time spent excessively performing one physical activity may limit opportunities to become competent and confident in a variety of physical activities. Therefore, the purpose of this study was to compare the physical literacy of children participating in elite sport or the Fit 4 Life afterschool physical activity program. Methods: The parents/guardians of 14 children from Fit 4 Life (9.1±0.6 years; 7 female, 7 male) and 11 from U9 Antigonish Bulldogs Hockey (8.1±0.3 years; 4 female, 7 male) provided consent for their children to participate in this study. The children provided their assent before completing the PLAYfun and PLAYself to provide a measure of their physical literacy. Results: No significant differences were found in PLAYfun (t-stat=1.73; p=0.49) or PLAYself (t-stat=1.71; p=0.07) total scores. Secondary analysis of the PLAYfun and PLAYself subscales showed the U9 hockey participants had significantly better upper body object control (tstat=1.72; p= 0.02) while the Fit 4 Life participants had significantly better balance, stability, and body control (t-stat=1.72; p=0.008). The Fit 4 Life participants also self-reported significantly higher confidence when performing activities in the gym (t-stat=1.72; p=0.004) and in the snow (t-stat=1.74; p=0.01) while the U9 hockey group self-reported significantly higher confidence when performing activities on the ice (t-stat=1.73; p=0.007). Conclusion: Participating in sport and recreation benefits children’s physical literacy in different ways. As such both should be promoted to children whenever possible
DMGNNs: Deep Multigraph Neural Networks for Drug-Target Interactions
No full textAccurate prediction of Drug-Protein Interactions (DPIs) is critical to understanding how drugs work and helping to accelerate drug discovery. Recent advances in Graph Neural Networks (GNN) have shown promise in effectively modeling complex relationships in biological networks. The Deep Multi-Graph Neural Networks for Drug-Protein Interactions (DMGNNs) framework, which integrates three specialized GNNs, is presented in this thesis: Drug-Drug Interaction GNN (DDI-GNN), Protein-Protein Interaction GNN (PPI-GNN), and Drug-Protein Interaction GNN (DPI-GNN). Compared to previous works, our novel approach distinctly divides the learning process into three separate tasks where drug-drug similarities, protein-protein similarities and drug-protein interactions are learned separately. For computing and learning similarities, DDI-GNN uses drug-drug graph features while PPI-GNN is based on protein-protein graph features. Once these two GNNs finish training, learned embeddings are passed to the DPI-GNN to predict drug-protein interactions. DMGNNs framework is a powerful approach for the accurate modeling of complex drug-protein relationships with potential applications in drug discovery and development. The results show that DMGNNs outperformed the state-of-the-art with an average improvement of about 28% using the F1-score. This confirms that modeling similarities of drug and protein graphs separately helps in extracting a more representative set of embeddings as compared to one combined graph learning task
The acquisition of symbiotic green algae Oophila amblystomatis in the egg masses of the spotted salamander Ambystoma maculatum
No full textThe unicellular green alga Oophila amblystomatis forms a mutualistic symbiosis with embryos in the egg masses of the spotted salamander Ambystoma maculatum. There is indirect evidence that O. amblystomatis is acquired by host egg masses via horizontal transmission from the surrounding pond water. An endosymbiotic interaction in which cells of O. amblystomatis invade tissues and cells of embryos has raised the possibility of intergenerational transmission of algae. If true, this would constitute the first known case of a vertically transmitted eukaryotic symbiont by a vertebrate host. For my Honours research I attempted to obtain direct evidence for horizontal transmission in this symbiosis. I conducted an experiment where gestating female salamanders were induced to oviposit in isolated chambers containing autoclaved pond water to which a wildtype (RK) or a green fluorescent protein (RK-GFP) transformed strain of O. amblystomatis was added. Egg masses were then examined for the accumulation of algae. Chambers containing normal and autoclaved pond water served as positive and negative controls, respectively, for algal invasion. A growth experiment was performed to verify the viability of algal strains in autoclaved pond water, as well as attempts to recover living RK-GFP and RK algal strains from the bins after egg masses were removed. Egg masses laid in normal pond water all accumulated algae, whereas only a few egg capsules in one egg mass laid in autoclaved water accumulated algae. By contrast, although RK and RK-GFP strains were viable in treatment conditions, no invasion of these strains into egg masses was observed, either by visual inspection or with a diagnostic PCR test. These results confirm that horizontal transmission is the dominant mode of symbiont acquisition, and vertical transmission is either rare or absent. The reason why neither purified strains invaded egg masses is intriguing and remains the subject of future work. When these same algal strains were recombined with isolated embryos in a co-culture experiment, the endosymbiotic interaction was observed, and intratissue algae were detected using a diagnostic PCR test. These results will permit, in further work, greater insight into the cellular arrangement of this endosymbiosis using GFP-tagged algae, and the use of molecular methods to answer questions about the endosymbiotic interaction
“As the Little Boy Grows, so also will his Manly Deeds”: Boyhood Deeds, Martial Training, and a Boy’s Coming of Age in Gaelic Society and Literature
No full textThis thesis examines heroic and historical literature of medieval Irish Gaelic and 17th to 18th - century Scottish Highland society with focus on the training of boys and young men. I will begin with examining what is known about the training of boys as described in the macgnímrada tales and laws of fosterage in Irish legal tracts. My historical analysis will be focused on recorded observations during the decline of the Scottish Highland Clan system. I will then synthesize the information to compare how boys and young men in the transitory state between childhood and adulthood were regarded in Gaelic society across these different time periods, analyzing similarities and developments of societal traditions and expectations
Plasmonic Gold Nanoplate Perovskites used in Photocatalytic Organic Transformations/Oxidations
No full textClimate change concerns are an ongoing societal problem. With this in mind, attention has been heightened to the use of light activated pathways to provide a means of exploiting renewable sources to improve the sustainability of many industrially relevant chemical processes. Photocatalysis is one such route of interest, but its true potential remains largely unrecognized and underdeveloped. Heterogenous semiconductor photocatalysts (metal oxides) are promising because of their chemical stability, resistance to photo-corrosion and potential recyclability. Further metal oxide functionalization with a light-activating material can expand the photocatalytic efficiency of the material to include activation by lower energy, visible light sources. Gold nanoplates are of great interest because of their localized surface plasmon resonance (LSPR), activated using red and near infrared light. Polyhedral gold nanoparticles also afford the added advantage of localized high catalytic activity at the vertices of the geometric structure, an added advantage over more common nanospheres. The staple of LSPR AuNP/metal oxide photocatalysis is the formation of a redox active electron-hole (e-/h+) pair by way of an interfacial electron transfer (eT) between the light-activated gold surface and the metal oxide. The aim of this thesis is to examine the ability of Au nanostructures with diverse morphologies, such as triangular and polyhedral shapes, to promote the formation of the reactive charge separated state and utilize this photo-redox activity in oxidative transformations. Chemically synthesized Au nanoplates adsorbed onto 3-mercaptopropionic acid (MPA) functionalized semiconductors will be examined as redlight (640 nm) activated catalysts for alcohol (Chapter 3) and amine (Chapter 4) photooxidations. The influence of reaction solvent, reaction time, light intensity and substrate substitution will be optimized to further extend the boundaries of heterogenous photocatalysis. The experimental design will be conscious of prioritizing the use of less toxic chemical reagents, such as hydrogen peroxide (H2O2), compared to traditional additives (permanganates, chromates, nitrates) and to ensure that any chemical by-products, in this case peroxide degradation to water, also adhere to the accepted Green Chemistry principles
Methods of Healing in Acallam na Senórach
No full textThis MA thesis discusses healing sequences in the Acallam na Sénorach, an Irish text dating from the 12th to 13th centuries, and how they can be defined within the parameters of supernatural, divine, and medical healing. It follows the head to heel (a capite ad calcem) layout of some medieval medical compendia, addressing each ailment and injury presented in the text. This thesis argues that there is an understanding of medieval medical theory demonstrated within Irish saga literature and that episodes of supernatural and divine healing have a foothold within European medieval medical practice
Taxonomic and Functional Diversity of Communities Associated with Rocky-Intertidal Foundation Species.
No full textBiodiversity is one of the most fundamental aspects of the environment and is vital in preserving the stability of ecosystems. It is therefore important to understand and maintain factors that influence biodiversity. This thesis aims to explore foundation species as one of these influences. The two methods of quantifying biodiversity that will be used are taxonomic diversity (diversity based on taxonomic grouping) and functional diversity (diversity based on functional traits) which allows for a combined consideration of what taxa are in the studied communities and also how those taxa interact with each other and their environment. This thesis is comprised of two independent studies that are each given their own chapter. In the first study, I ask: “Do functionally distinct foundation species host taxonomically and functionally unique communities?” I hypothesized that the communities associated with each foundation species would differ both taxonomically and functionally and the functional composition of the associated communities would be related to the functional properties of the foundation species themselves. On the rocky shore of Nova Scotia near Duncan’s Cove, I collected patches of Mytilus spp. and Chondrus crispus including their associated communities. These species are distinct in their form and function; one being a hard-shelled consumer and the other a flexible primary producer. However, they are both common foundation species that occur in dense stands in the mid-to-low intertidal zone in Nova Scotia. I identified 29 invertebrate taxa from 7 phyla and found a marked difference in species composition and taxonomic diversity between both community types. The communities also differ drastically in their functional trait composition, despite having similar values from functional diversity metrics. These findings indicate that the functional properties of foundation species occurring in the same environment may influence the functional properties of the associated communities. In my second study, I ask: “Do mussel beds across the globe provide habitat to similar invertebrate communities?”. I hypothesized a striking difference in the taxonomic composition of the associated communities but a larger overlap in the functional traits that such communities exhibit due to the similarities in the functional properties of the mussels hosting them. I analyzed 10 datasets of invertebrate communities associated with mussel beds in temperate-rocky shores across the globe from the north-east, south-east, north-west and south-west Pacific as well as the north-east, south-east, north-west and south-west Atlantic. I compared coasts based on taxonomic and functional diversity (based on functional traits). The results reveal that, globally, mussel bed communities have many similarities. Firstly, they hold similar numbers of species per unit area. Moreover, multivariate comparisons based on coarse taxonomic groups and functional traits revealed a noticeable overlap in the communities that inhabit mussel beds on different coasts. Overall, the ability of these mussels to host similar communities despite local and regional environmental differences emphasizes their importance in maintaining both community functions and biodiversity of the rocky intertidal. Combined these two studies compare the effect of the foundation species and the effects of the environment on the faunal community. The results indicate that functionally different foundation species in the same environment hold very different communities but functionally similar foundation species in different environments have more overlap in their associated communities. It is therefore possible that in my studied systems, the functional properties of foundation species play a bigger role in determining the assembly of associated communities than environmental conditions. In this way, these studies highlight, from a novel perspective, the influence of foundation species on biodiversity within the environments they inhabit