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Hadron spectroscopy in light-front holographic QCD with the 't Hooft equation for longitudinal confinement
Full text linkSynthesis of novel boron-containing capsaicinoids
Full text linkIn recent years following the approval of a significant number of organoboron pharmaceuticals, the incorporation of boron into drug design and development has become very attractive. While capsaicin, the principal ingredient that gives chilli peppers their pungent heat, possesses medicinal properties, capsaicinoids containing a boron moiety remains entirely underexamined. To address this gap in knowledge, this study has successfully synthesized eight novel capsaicinoids via a multi-step divergent synthesis approach using readily available reagents. These compounds have been characterized using spectroscopic methods and melting point determination. However, mass spectrometry or elemental analysis should also be carried out to fully characterize these capsaicinoids. The immediate next step of this study involves the hydroboration of the synthesized capsaicinoids using a metal catalyzed approach to afford the target organoboron compounds. Following this, biological testing will be conducted to provide insights into the medicinal properties of these novel capsaicinoids
Exploring the damage number of a graph
Full text linkCops and Robbers is a well-studied pursuit-evasion game, where a set of cops aims to capture a robber on a graph while the robber attempts to avoid capture indefinitely. We consider the damage number of a graph, in which the original goal of the players in Cops and Robbers is altered. In this game, the robber's goal is to visit the maximum number of unique vertices in a graph while the cops' goal is to minimize this number. Although the damage number of a graph can be studied with any number of cops, we will consider the game with a single cop and robber. We present new results which characterize graphs with damage number one, provide an improved lower bound on the damage number for any graph, and determine the exact value for the damage number of graph joins. Following this, we provide a relationship between cut-sets and the damage number by defining a new graph property, star cut-sets, and explore
this property through cactus graphs
Acid-catalysed dissolution of iron in brake wear aerosol
Full text linkIdentifying sources of water-soluble iron (WS-Fe) in the environment is important in understanding the biogeochemical iron cycle and because of human health impacts associated with exposure to iron-containing aerosol. A main mechanism of iron solubilisation is through acid-catalysed reactions in atmospheric aerosol and cloud droplets. In this study the acid-catalysed dissolution of iron in brake wear aerosol was investigated to determine whether brake wear could be an anthropogenic source of WS-Fe. It was found that the iron in brake wear particles becomes soluble when suspended in solutions similar to atmospheric aerosol pH conditions and that the dissolution happens quickly enough to be atmospherically relevant. In solutions of nitric acid and sulphuric acid at pH 1, 2, and 3, 50-100% of available iron was dissolved within 10 hours. The dissolution was found to be very pH dependent, with an approximately 90% decrease in dissolved iron when pH is increased from 1 to 4, suggesting the reaction is highly proton driven. The dissolved iron was speciated and it was found that 75 ± 2.5% was Fe(III) and 25 ± 2.5% was Fe(II) for solutions of sulphuric acid at all pH levels and nitric acid at pH 2-4. However, in nitric acid solutions at pH 1, Fe(II) was completely oxidised into Fe(III). It was found that this oxidation increased with increasing nitrate concentrations at pH 1, suggesting nitrate has a role in the dissolution of iron. These results show that brake wear aerosol could be an important anthropogenic source of WS-Fe in the atmosphere
Oxidative potential of aerosol emitted from traditional vs. improved cookstoves
Full text linkFine particulate matter (PM2.5) emitted from combustion processes can partake in cellular redox reactions and induce oxidative stress. This ability for PM2.5 to induce oxidative stress is known as its toxicity and is referred to as oxidative potential (OP). This poses a serious health risk for the ~3 billion people globally who continue to rely on biomass burning for their cooking needs as it is a significant source of indoor PM2.5. To combat the problem associated with traditional biomass burning cookstoves, ‘improved’ biomass burning cookstoves have been developed which have been shown to reduce the mass of PM2.5 generated. However, it is unknown whether the overall exposure to toxic chemicals contained in PM2.5 is reduced using these cookstoves as the adverse health effects of PM2.5 are better linked with OP than mass of PM2.5 inhaled. The goals of this study were to determine whether the OP of PM2.5 emitted from improved cookstoves was reduced and to determine what effect fuel type has on the OP of PM2.5. To test this, 4 fuel types (2 wood types and 2 charcoal types) were burned in 5 cookstoves (2 traditional and 3 improved) using the simmer-phase of the Water Boiling Test protocol to generate PM2.5 samples that were collected on quartz filters for analysis. The dithiothreitol (DTT) assay was employed to determine the OP of the PM2.5 and was split into 2 fractions, the water-soluble (WS) and total fraction. The DTT activity values were corrected using two variables, mass (OP(DPP/Mass)) and volume (OP(DPP/Volume)). The mass emitted from the 3 improved cookstoves were found to significantly reduce PM2.5 compared to the traditional stoves, consistent with previous studies. (OP(DPP/Volume)) was found to be more representative of the overall exposure to toxic PM2.5 emitted during a cooking event as it accounts for both intrinsic OP of the PM2.5 (toxicity per mass of PM2.5) and the mass emission of PM2.5. The (OP(DPP/Volume)) values were compared for all cooking methods and the wood fuel types were found to have the greatest (OP(DPP/Volume)) for each cookstove. Using the experimentally determined (OP(DPP/Volume)), example mitigation strategies were then suggested. Given the option to only switch cookstove or fuel type from the 3-stone with hardwood cooking method, a greater reduction in (OP(DPP/Volume)) can be achieved by switching from wood to coal (84% reduction) rather than 3-stone to improved stove (62% reduction). WS data was found to vary in its contribution to the total (OP(DPP/Volume)) from less than 15% to just below 75%, suggesting that the chemical composition of components that contributed to the OP of PM2.5 is dependent on cooking method
X-ray fluorescence of selenium and zinc applied to toenail clippings from breastfeeding women of New Zealand and their infants
Full text linkZinc and selenium are essential micronutrients that play essential roles in structures of zinc finger proteins and selenoprotiens, both of which have vital roles in complicated biological processes of human body. Micronutrient status is especially vital in postpartum women as their requirements significantly increase during breastfeeding, escalating the risk of deficiency. Moreover, in New Zealand, selenium content of most of the arable land is low and selenium deficiencies have been a major concern since first observed as white muscle disease in livestock in the 1980s. Toenail trace element concentrations have been shown to be reflective of their long-term status in several studies. The current study employs portable X-ray fluorescence (XRF) spectrometry as a means of investigating zinc and selenium levels in toenails of mothers and their infants from New Zealand. 240 XRF measurements were carried out using 20 matched-sets of toenail clippings of mothers and newborns participating in the MINI study. Strong linear relationships were found in the case of both elements with a “gold standard” technique, inductively coupled mass spectrometry (ICP-MS), that were all highly significant. These correlation coefficients were highest for zinc using the XRF system’s automated output (r = 0.82), and for selenium using normalized selenium signals from every spectral analysis (r = 0.73). Thickness contributions to XRF concentrations were found to be minor and ICP-MS concentrations showed similar trends against thickness as with the XRF techniques. Low selenium status was suspected in 3 mother-infant pairs whereas zinc levels were in the normal range. The results of this study indicate that portable XRF provides reasonable estimates of zinc and selenium concentrations. However, further method development is required before it can be considered as interchangeable with the ICP-MS method
Evaluating the toxicity of silver nanoparticles on the behaviour and and physiology of bristlenose catfish (Ancistrus cirrhosis)
Full text linkSilver nanoparticles (AgNPs) are a common material found in many household items, but as these items are thrown out, AgNPs can leach into the aquatic environment, and are currently being found in increasingly higher concentrations in our water supply. In the aquatic environment, AgNPs aggregate and fall to the bottom, affecting benthic creatures. In this study, the Bristlenose Catfish (Ancistrus Cirrhosis) was used for their benthic nature and their ability to air breathe using their highly vascularized stomachs. By analyzing air breathing frequency (seen only in times of stress), we can better understand what role AgNPs play in a catfish’s ability to tolerate environmental stress. Experimentation was done by isolating catfish for seven days with the absence or presence of AgNPs. On the eighth day, these fish were exposed to one of three environmental conditions: control (optimal conditions), hypoxia (20% O2 saturation), and high temperature (32°C). These fish then had their movement tracked and quantified over 6 hours. In addition to this, fish were placed in a respirometer to measure oxygen consumption, gills were analyzed via scanning electron microscopy, and gut samples were used to determine malondialdehyde (MDA) concentration. It was found that fish regardless of environmental stressor or AgNP presence total distance moved did not change. However, hypoxic fish exposed to AgNPs were found to increase air breathing frequency. This indicates that any movement the catfish is doing is focused on air breathing, which could increase their exposure to aerial predators. Respirometry analysis showed an increase
in oxygen consumption only when AgNPs are present, which is in keeping with behavioral data, since an increase in basal oxygen consumption would lead to a higher air breathing frequency. MDA levels varied between environmental stressors in AgNP exposed fish, but qualitative gill analysis indicated that the gills were not damaged from nanoparticles. Together, these results support our hypotheses that AgNPs do interfere with a catfish’s ability to tolerate environmental stress. It is expected that with an increase in concentration or exposure times, these effects would increase proportionally
Influence of diel thermal variability on growth, development, swimming performance and stress response in salmonid fishes
Full text linkAccurately understanding the biological effects of temperature is important for effective species conservation, especially in this era of climate warming. Traditionally, temperature effects on fishes have been understood using fish held at stable temperatures. In many natural freshwater fish habitats, however, water temperature cycles daily. Diel thermal cycles can be as wide as 5-9 C in key salmonid habitats like the Miramichi River in New Brunswick. To date, little is known about the biological effects of diel thermal cycles on fishes. In my thesis, I investigated the growth, development, and swimming performance of Atlantic salmon (Salmo salar) under 16-21 and 19-24 C diel thermal cycles (representing cool and warm sites in the summer at the Miramichi). Additionally, I examined the stress response and post-angling survival of brook trout (Salvelinus fontinalis) after exposure to diel cycles with different daily thermal maximums (24, 26, or 27 C). I found that Atlantic salmon grew at similar rates at 16-21 and 19-24 C as parr, but smolts grew slower at 19-24 C especially for those from the relatively cooler Restigouche river compared to those from Miramichi. Atlantic salmon swimming efficiency was insensitive to acute warming or acclimation thermal cycle while sustainable swimming capacity stayed >90% (of the maximum) at the warmest test temperature (24 C) for both acclimation groups. Overall, Atlantic salmon appeared more resilient to warm temperatures than thought based on stable temperature experiments. Brook trout increased metabolic rate above resting levels after 26 or 27 C exposure which also increased some reflex impairments predicting greater postangling mortality. Tmax may be an important factor to consider in future closing/opening of recreational fisheries which currently considers some other water temperature parameter
Trajectories towards transformation: An abolitionist analysis of student organizing at Mount Allison University
Full text linkThis thesis explores student organizing at Mount Allison University through frameworks of analysis derived from prison abolitionists. In the context of the research, abolition is regarded as a broad theory of emancipation and social transformation, presented in conjunction with theoretical perspectives on Black Marxism, decoloniality, and critical pedagogy. Seven semi-structured interviews were conducted with self-identified student organizers, surrounding the themes of accountability and social change. A qualitative analysis was conducted on the contents of the interviews. Three major themes emerged: neoliberal organization, community accountability, and transformative practices. In the following chapters, these themes are analyzed in correspondence with existing literature, which draws from the works of scholars and organizers such as Angela Davis, Paulo Freire, Ruth Wilson Gilmore, and Mariame Kaba. Additionally, the research also references studies on other social movements, including the Zapatista Movement, the Maple Spring protests, the Sir George Williams University student uprisings, and the fossil fuel divestment movement. The findings reveal the importance for developing critical consciousness and community accountability practices in organizing, as well as identify the reproductive role of neoliberal institutions
Transforming spaces of learning: The implementation of a gay-straight alliance in rural maritime community
Full text linkThis thesis is an exploration of how gay-straight alliances (GSA) can create community amongst queer youth and present an opporunity for transformative change. I conducted five interviews with GSA advisors at a small, maritime school. Participants' accounts reflected the emancipatory pedagogy that emerged from the GSA, as well as reflections on allyship and communion with the oppressed. The findings of this study point to the clear need to have safe spaces in schools and how these queer youth need to be prioritized in instuitional reform. These GSAs act as a small piece of the necessary institutional reform
required to disrupt the subject-object relationship between queer youth and their oppressors