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  • Can low-dose lithium supplementation protect against sarcopenic obesity in ovariectomized mice?

    Marcella, Bianca Marie; Applied Health Sciences Program
    During menopause, females lose the protective effects of estrogen and are at risk for age-related diseases, including sarcopenic obesity. Sarcopenic obesity is the coexistence of excess adiposity and muscle atrophy and weakness that is associated with age. Glycogen synthase kinase 3 (GSK3) is a well-known negative regulator of muscle mass, strength, and the oxidative fibre type, and has been associated with weight gain and obesity. Our lab has found that inhibiting GSK3 using low-dose lithium (Li) supplementation improves skeletal muscle function, elevates whole-body energy expenditure, and enhances insulin sensitivity in male mice. However, it is unknown whether GSK3 inhibition will have similar benefits in female mice in the presence and absence of estrogen. The purpose of this thesis was to investigate whether low-dose Li supplementation can protect against sarcopenic obesity in ovariectomized (OVX) mice. 28-week-old sham and OVX C57BL/6J mice were divided into a control (con) or Li group, giving rise to four groups: sham-con, OVX-con, sham-Li, and OVX-Li (n = 6-10 per group). OVX-Li mice were provided a dose of 50 mg/kg/day of Li via drinking water for 8 weeks. Energy expenditure was higher in Li-treated mice compared to control mice. However, this increase in energy expenditure did not alter body composition. Force production of soleus and EDL were significantly lower in OVX-con mice compared to sham-con. Li supplementation increased force production of soleus and EDL in OVX mice. Muscle fatigability was improved in soleus, but not EDL, of sham and OVX mice provided with Li supplementation. Glucose handling and insulin sensitivity were not affected by Li treatment, however, fasting blood glucose levels were improved with Li supplementation in OVX mice. OVX-Li mice had greater cage activity than OVX-con mice, which suggests improved muscle function. OVX mice had lower bone mineral density than sham mice, however, this was increased with Li supplementation. In conclusion, low-dose Li supplementation did not alter body composition or glucose handling in OVX mice, but did improve force production, fatigue resistance, energy expenditure, fasting blood glucose levels, cage activity, and BMD, suggesting that GSK3 inhibition may protect against muscle weakness associated with estrogen loss.
  • Understanding the Link Between Affinity for Solitude and Psychosocial Adjustment During Adolescence

    Borg, Meghan E.; Department of Psychology
    Time spent alone increases from childhood into adolescence. Some previous research suggests that solitude is a constructive experience, whereas other researchers argue that spending time alone may have negative implications for peer relationships during adolescence. Less is known about how different characteristics of solitude may be differentially associated with adjustment. The primary goals of my dissertation were 1) to explore whether the link between affinity for solitude and psychosocial adjustment depends on why or how often an adolescent spends time alone, 2) assess whether there are individual differences in patterns of attitudes towards solitude and experiences with solitude, and 3) identify when solitude is most associated with maladjustment during adolescence. Study 1 of my dissertation used a sample of early and mid- adolescents to examine whether affinity for solitude predicted psychosocial adjustment (i.e., depressive symptoms, social anxiety, peer victimization, friendship quality, self-esteem), controlling for previous scores on these indicators from two years earlier, and whether motivations for spending time alone (i.e., positive versus reactive) and frequency of time spent alone moderated this association. Study 2 used a person-centered approach to identify subgroups of adolescents who varied in characteristics of solitude and sociability, and then assessed whether there were group differences in earlier and concurrent psychosocial adjustment (i.e., depressive symptoms, social anxiety, peer victimization, friendship quality). Study 3 extended Study 2 to explore whether these groups of adolescents with different patterns of characteristics of solitude and sociability experienced changes in trajectories of psychosocial adjustment after the start of the COVID-19 pandemic, and whether the pandemic had a stronger effect for some groups compared to others. Overall, results indicated that affinity for solitude is relatively benign during adolescence, though this depends on why and how often adolescents spend time alone, as well as whether adolescents desire to be around others. Further, the implications of solitude may depend on contextual factors, such as the pandemic. Taken together, my dissertation highlights the importance of considering multiple characteristics of solitude, as well as sociability, to avoid broadly over pathologizing solitude during adolescence.
  • Synthesis and structural studies of nucleic acids

    Li, Quanjian; Department of Chemistry
    The first project focused on the synthesis of 4-15N-2′-deoxycytidine as a tool to study the B- to Z-DNA transition using 15N NMR. This study investigated alternative methods for synthesizing 15N enriched 2′-deoxycytidine at the 4-NH2 position. As a model study, ammonium chloride was used as the 15N source to synthesize 5-methyl-2′-deoxycytidine from thymidine. This chemistry was successfully applied to the synthesis 4-15N-2′-deoxycytidine from 2′-deoxyuridine. In addition, the 15N NMR detection limit was also established to determine the feasibility of studying DNA structures using 15N 1D NMR. The second project involved finding ‘difficult sequences’ in solid-phase oligonucleotide synthesis through phosphoramidite chemistry. Using 18-mers as models, all mathematically possible repeating trinucleotides, dinucleotide, and mononucleotide sequences were synthesized, and the overall yields were analyzed by anion exchange high performance liquid chromatography. It was concluded that depurination was a major contributor to decreased yields in purine-rich sequences. In addition, certain dinucleotide-repeat sequences, especially d(CG) and d(GC), were associated with low overall yields for reasons unknown at this time. The last project involved the identification of alternative detritylation composition for industrial solid-phase oligonucleotide synthesis. These compositions include acids, solvents, and carbocation scavengers. The acid currently used in industrial oligonucleotide solid-phase synthesis is dichloroacetic acid, which has a short shelf life and contains impurities that react with the desired reaction product. For solvents used in the detritylation reaction, toluene and dichloromethane are currently used. While dichloromethane is not preferred in industry, toluene has been known to swell the polystyrene solid support creating an issue during detritylation. Furthermore, the use of carbocation scavengers helps to remove the cleaved DMTr+, preventing it from re-protecting 5′-OH. However, some scavengers have been reported as problematic for this purpose. The results of this project provided a potential alternative acid, namely difluoroacetic acid, investigated and explained the reason for the current solvent choice, and studied the feasibility of scavengers used in the literature.
  • Aspects of bioorganic chemistry - a). Development of caffeine-aptamer for coffee decaffeination; b). Study of 1,8-naphthalimide derivatives as fluorescent probes; c). Encapsulation of DNA by silica nanoparticles

    Betancourt, Frank; Centre for Biotechnology
    Research described in this thesis encompass three aspects of bioorganic chemistry: Caffeine- binding aptamers were sought to remove caffeine from coffee brew. Toward this goal, theophylline carboxylic acid and caffeine carboxylic acid were synthesized, and immobilized to ω-aminohexyl–agarose. The immobilized compounds were used for aptamer selection. The ionic composition of medium roast coffee grinds was determined by ICP-MS. In addition, the amounts of caffeine and theophylline in these brews were also determined by UV/vis and HPLC. The work described in this thesis provided the foundation for future aptamer selection. The development of 1,8-naphthalimide derivatives was motivated by an ability to stain biomolecules based on differences in their hydrophobicity. 1,8-naphthalimide derivatives were synthesized, and their photophysical and staining properties were investigated. The fluorescence intensity of 4-phenyl-1,8-naphthalimide was found to be very sensitive to solvent polarity, where the compound is virtually non-fluorescent in DMSO, large folds of fluorescence turn-on were seen in less polar solvents. Furthermore, this compound showed aggregation-induced emission characteristics. 4-Aryl-N-ethoxyethyl- and N-[2-(2-hydroxyethyoxy)ethoxy]ethyl-4-aryl-1,8-naphthalimide derivatives were also synthesized, with various aryl substituents (methoxy, amine, dimethyl amine, acetanilide). These compounds were found to be highly fluorescent in chloroform but were drastically reduced in DMSO and methanol. These dyes were found to be suitable probes for protein hydrophobicity, with up to 80 fold fluorescence turn on in the presence of BSA, but virtually no change in myoglobin. The thesis also explored the encapsulation of DNA by SNPs as an approach to protect DNA. Toward this goal, commercial SNPs were functionalized by the treatment with TMAPS and TEOS introducing a surface positive charge. Upon deposition of DNA to the positively charged surfaces, encapsulation was carried out by treatment with TMAPS and TEOS in the presence of ammonium hydroxide. This encapsulation protocol was first demonstrated using Reactive Green-19. In addition, DNA was readily encapsulated and released by the treatment with ammonium hydroxide at 60°C for six hours, and amplified by polymerase chain reaction and detected by gel electrophoresis. The SNP-encapsulated DNA was found to pass through beds of sand and could therefore be used in environmental tracking in sandy conditions.
  • Multi-Scale Analysis of Climate Change: Case Study of Major Canadian Wine Areas

    Simiganoschi, Pierre; Department of Earth Sciences
    The release of anthropogenic greenhouse gases (primarily CO2) is estimated to have caused an average increase of 1.2 ℃ in global warming since pre-industrial times (1850–1900) and is projected to continue its rise based on Global Climate Models. This study uses Regional Climate Models to evaluate the effects of climate change on three well-known wine regions in Canada: the Niagara Region, the Annapolis Valley, and the Okanagan Valley. Nineteen models were evaluated against historical trends from 1950 to 2021 to find the most accurate and precise model for each region. Using model data, two types of climate indices, Climate Suitability and Climate Risks, with a total of ten parameters, were used to assess the impacts of climate change on the wine and grape industry. All of these are important for winegrowers with more focus put on the number of heat (GS-HD), frost (GS-FD), and growing degree days (GDD). Under the business-as-usual scenario (GHG emissions, RCP 8.5) from 2020 to 2100, the Niagara Region, Annapolis Valley, and Okanagan Valley will likely experience increases in GS-HD of 30, 23, and 55, respectively. Additional impacts arise from the change in the number of GDD increasing by 764, 980, and 912 in respective regions. Thus, all three regions will move into a “hot” climate based on the Winkler Index. When we, as a society, are successful in mitigating CO2 emissions to an RCP 4.5 scenario, then GS-FD are predicted to decrease between 2020 and 2100 by just 10, 11, and 35 in Niagara, Annapolis, and Okanagan, respectively. During the same period, the GDD will increase by 465, 306, and 443, allowing them to grow more varieties of grapevine that thrive under a warmer climate. Overall, each locality will reap more benefits from increasing temperatures under the RCP 4.5 scenario than the RCP 8.5 one. It is regional-scale studies of Climate Change, employing Regional Climate Models, that the wine industry needs to make sustainable decisions appropriate to the local level, whether they are established or emerging wine growing regions. Finally, location-specific Regional Climate Models may be invaluable instruments in aiding/sustaining the agricultural industry.
  • Dynamics of Simultaneous Arboviral Infection in Host and Vector Cells

    Garrido de Castro, Mariana; Department of Biological Sciences
    In this study, simultaneous infection dynamics were investigated in mammalian and insect cells. Mayaro virus (MAYV; genus Alphavirus), West Nile virus (WNV; genus Flavivirus), and Zika virus (ZIKV; genus Flavivirus) were the arboviruses used in the pairings. Arboviruses are transmitted by arthropods, and Aedes sp. mosquitoes are vectors of multiple viruses, including all three used in this study. In addition to sharing some of the same vectors, MAYV, WNV, and ZIKV can all infect humans. To understand whether the presence of another virus affected viral infection dynamics, mammalian-derived Vero and insect-derived C6/36 cells were infected with either MAYV and ZIKV or WNV and ZIKV. In nature, a simultaneous infection can occur through either coinfection or superinfection, and both conditions were studied here. Infection dynamics were assessed by quantifying viral RNA production for 6 days following infection, using RT-qPCR. Simultaneous MAYV + ZIKV and ZIKV + WNV infections impacted infection dynamics. Interestingly, the outcomes seen in simultaneous infections of Vero cells were similar for both pairings. Viral accommodation was seen in coinfection conditions, as no change was seen in RNA levels for either virus in the pairing. The order in which the viruses infected the cells changed the outcome in superinfection conditions in Vero cells – viral accommodation was observed when ZIKV was the first to infect the cells, while superinfection exclusion was seen when ZIKV tried to infect Vero cells already infected with either MAYV or WNV. In C6/36, replication differed between the virus pairings studied but did not differ between coinfection and superinfections. Viral interference was observed for conditions where MAYV and ZIKV simultaneously infected C6/36 cells, while virus accommodation was at play when the virus pairing consisted of WNV and ZIKV.
  • Academic Competition in the School System: At What Cost?

    Matusof, Perla; Department of Psychology
    Competition pervades our culture across sports, entertainment, politics, and corporations, seeping also into educational institutions. Today, children are urged not only to "play to win" but also to "learn to win." Despite awareness of competition's negative psychological and social impacts, it remains a cornerstone of the educational system as it is perceived as a strong motivating factor for academic achievement. However, academic competition has received less attention than its athletic and social counterparts, with previous research often overlooking its effects on interpersonal relationships. Existing studies have either used inappropriate measures for academic settings or failed to differentiate between other-referenced and task-oriented competition, which respectively focus on surpassing peers for status and on personal growth. This thesis introduces new scales tailored for assessing academic competition among adolescents. A pilot study involving 532 adolescents in southwestern Ontario (Mage =15.23) validates these scales through factor analysis using Principal Component Analysis, distinguishing between other-referenced and task-oriented competition. The new scales demonstrate reliability, with Cronbach's alpha coefficients of .789 for other-referenced competitiveness and .825 for task-oriented competitiveness. Regression analyses reveal a significant positive association between other-referenced competitiveness and bullying perpetration, while task-oriented competitiveness shows a moderate inverse relationship with bullying. These findings underscore the need to differentiate between competition for skill development and for status, as the latter may inadvertently foster bullying tendencies. This study emphasizes the importance of nuanced understanding in academic competition and its implications for student well-being. The discussion encompasses implications, limitations, and avenues for future research in this area.
  • Diversity of cover crops in two organic vineyards in the Niagara Region, Canada, as an adaptation measure to climate change

    Tosato, Diana Ribeiro; Department of Biological Sciences
    Vineyards are agroecosystems of great importance in the Niagara Region, Ontario (Canada). Due to its microclimate, this region is projected to be impacted by climate change with temperature increases, changes in precipitation patterns in all seasons, and greater frequency of extreme weather events. The aim of this thesis was to explore the projected changes for the weather in the Niagara Region, Canada, summarize which seasonal changes are expected and assess how such changes are likely to affect the key components of the vineyard ecosystem (i.e., soil, vines, invertebrates, and pathogens). It is expected that by 2080 the region will experience an increase in temperature in all four seasons; an increase in precipitation during the fall, winter, and spring; and a decrease in precipitation during summer months. Impacts of the projected changes will likely lead to vine water stress, yield loss, increases in incidents of diseases, increases in the spread of new pests, and changes in grape quality ultimately resulting in lower wine quality and/or production. Current management practices will need to be better understood and adaptive strategies introduced to enhance grape growers’ ability to minimize these impacts. The research also aimed to test the performance of four different cover crops in monoculture or in mixture in two organic vineyards. Of the planted species, rye grass and hairy vetch showed a great establishment, while pearl millet did not establish due to weed pressure. The ecological indexes (Shannon, Simpson’s, and Evenness) values showed that there is significant difference in cover crop diversity between growing seasons and collection months (June/September) in Vineyard #2, and in richness in Vineyard #1, indicating fluctuations in community composition over time. These results suggest a dynamic ecosystem response to seasonal and annual variations. These results may be used to increase the knowledge about the expected future for the vineyards in the region in face of climate change, and into one of the alternative management techniques that can help mitigate the impacts of changes in temperature and rainfall increase of extreme events in the region.
  • Determining the effect of different cover crops on nematode communities in vegetable production

    Aubry, Elyse; Department of Biological Sciences
    Agricultural soil environments contain different types of nematodes, part of several trophic levels that aid in balancing the soil food web. Beneficial free-living nematodes (FLNs) consist of bacterivores, fungivores, predators and omnivores that help in the mineralization of the soil and the top-down control of damaging plant-parasitic nematodes (PPNs). Conversely, PPNs feed directly on plant roots and cause $125 billion in worldwide crop losses annually, making them a plant pathogen of great concern for growers. Farmers have started to implement the use of cover crops in agricultural systems for the protection and enrichment of soil but research on how different covers affect nematode populations is lacking and in demand. This study aims to determine the effect of legume and grass cover crops, cow pea and pearl millet, as well as their mixture on the abundance and diversity of FLN and PPN populations. Soil samples were taken prior to, during, and after cover crop implementation to analyze nematode communities using morphological and DNA metabarcoding techniques. Results showed that the implementation of cow pea and pearl millet covers as well as their mixture in a spinach agricultural system led to the control of PPNs and the proliferation of FLN communities. Specifically, we found that the mixture of both cover crops and the use of pearl millet as a single species generated healthier nematode populations with significantly less PPNs and more FLNs when compared to the control and fallow plot treatments using both nematode identification methods. However, the choice of cover crop to implement by growers should be based on specific soil health needs to promote a healthy soil and nematode population. Ultimately, understanding how different cover crops impact nematode populations can inform sustainable agricultural management practices. By strategically selecting legume and grass cover crops, farmers can optimize soil health, reduce crop losses caused by PPNs, and promote a balanced soil ecosystem to improve crop productivity.
  • Using Multiple Exemplar Training to Increase Fitness to Stand Trial

    Totino, Micaela; Center for Applied Disability Studies
    Fitness to stand trial refers to an individual’s capacity to comprehend judicial proceedings related to a crime they have committed. There currently exists no legally codified or empirically validated procedures for training fitness in forensic inpatients with mental health diagnoses, developmental diagnoses, or dual diagnoses. The purpose of this study was to develop a teaching procedure based on multiple exemplar training (MET) that provides a procedural foundation for training fitness. Broadly, this study sought to yield the first objective teaching procedure and measurement system for improving fitness based on the principles of behaviour analysis. Specifically, MET was used to develop a variety of stimulus (questions) and response topographies, which were presented to participants and designed to increase acquisition of targets related to fitness. Results from one completed participant and three partial datasets provide preliminary to support MET as a procedure for increasing fitness, as indicated by an increase in correct responding across to all questions related to an individual’s fitness to stand trial. This study has implications for both judicial system and hospital settings, as the empirical validation of a standardized approach to training fitness could serve to streamline service delivery and mitigate the common barriers experienced by individual with dual diagnoses during legal proceedings.
  • Investigating the Importance of Physiological Cell Culture Conditions in Modeling Cancer Metabolism and Metabolic Reprogramming

    Gardner, Georgina; Department of Biological Sciences
    Standard cell culture conditions do not mimic the physiological environment of cancer cells. Traditional culture media contain metabolites at concentrations that far exceed conditions measured in vivo, and oxygen is often unregulated, exposing cells to atmospheric oxygen concentrations (~18%), rather than the 0-3% O2 measured in solid tumours in vivo. Recently, plasma-like media have been developed to address these limitations, aiming to improve culture conditions and maintain biologically relevant cancer phenotypes in vitro. However, these conditions remain unrepresentative of interstitial fluid in solid tumours. The goal of this thesis was to investigate how physiological culture conditions affect cancer cell behaviours, specifically cell metabolism and adaptive metabolic responses. In the first data chapter of this thesis, I explored nutrient exhaustion in physiological plasma-like medium (Plasmax) at 18% and 5% O2, and the adaptive mechanisms by which cancer cells can maintain survival under metabolic stress conditions. Here, I found that glucose and amino acid depletion from Plasmax over 48 hours is associated with several adaptive mechanisms consistent with metabolic reprogramming in vivo. Given these responses, I hypothesized that a media formulation designed using metabolite concentrations from tumour interstitial fluid may modulate metabolic phenotypes in a similar manner, providing a more physiologically relevant culture model for cancerous cells. Data chapter 2 addresses this hypothesis, whereby I formulated a novel cell culture medium using quantitative metabolite data from murine pancreatic ductal adenocarcinoma (PDAC) tumour interstitial fluid, named Tumour Microenvironment Medium (TMEM), and investigated the effects of TMEM and 1.5% O2 on an adapted murine PDAC cell line (KPCY). Importantly, I found that tumour-like conditions elicited a substantial transcriptional and functional response in cultured cells, modulating cell proliferation, migration, glucose utilization, and mitochondrial bioenergetics in ways relevant to in vivo cancer biology. Overall, the results of this thesis highlight the responsiveness of cultured cells to their environment, and the importance of representative culture conditions in the acquisition of biologically accurate experimental data.
  • Properties of a flexible visual short-term memory resource

    Lockhart, Holly; Department of Psychology
    For the last few decades, there has been considerable debate as to whether visual short-term memory (VSTM), the capacity limited memory system for the short-term storage of visual information, is a continuous or discrete resource. One property that has been identified that is consistent with a continuous resource is flexible allocation; in a delayed- recall task, when cues manipulate the priority (task relevance) of the sample items to decouple resource allocation from set-size, performance has been found to vary with the proportion of allocated resources. However, the extent and limits of this property have yet to be identified. Moreover, discrete resources could account for some previous findings through probabilistic encoding. The current thesis aimed to examine the properties and limits of flexible resource allocation in VSTM. In Chapter 2, I examined whether VSTM resources could be allocated to three levels of attentional priority. Although possible, examining individual differences in the strategies participants used revealed that the majority of participants do not use all three priority levels. Chapter 3 investigated an alternative resource allocation strategy, whereby the strategic use of a discrete memory resource to store the most relevant memory items would be encoded probabilistically. Response precision better matched predictions of flexible allocation. Further, I directly tested probabilistic encoding by estimating the proportion of “in-memory responses” and comparing it with individuals’ estimated capacity. Results again did not support a probabilistic encoding strategy. A criticism of flexible allocation is that very low precision memories are indistinguishable from out-of-memory responses. In Chapter 4, I examined flexible allocation using a two alternative forced choice (2AFC) task intermixed with continuous response trials, as 2AFC can show evidence of weak memory through better-than-chance recognition performance. Results demonstrated that participants performed better than chance for very low-priority items. This suggests that these items are stored as low-resolution memory representations, rather than being out of memory altogether. Collectively, these studies reveal properties of a flexible VSTM resource. Taken together, these data further suggest that any model that cannot accommodate a dynamic, flexible resource should be abandoned.
  • Chinese women players’ experiences of oppression and resistance in Honor of Kings

    Le, Jiayi; Applied Health Sciences Program
    Guided by a Chinese intersectional feminist theory perspective, this research identifies and describes the lived experiences of women’s oppression that Chinese women have while playing HoK, the consequences of these experiences for Chinese women who play HoK, and the resistance and coping strategies they use to deal with these experiences. Women’s oppression includes the systemic and often discriminatory challenges and barriers faced by women, in this case within the esports industry and with women’s gaming identities. While esports continue to grow into a multi-billion dollar industry, issues of gender-based harassment, discrimination, and violence within the industry similarly continue to grow. Several research studies have separately examined these issues in esports, but very little research has intersectionally examined the experiences of Chinese women. The context of esport in China is of particular importance to study, not only because of the sheer size of the esport industry in China but because of the complex history of gender relations in China, with women experiencing limits to their inheritance rights, education rights, marriage freedoms, social rights, and political rights. 10 semi-structured interviews (SSIs) were conducted with women HoK players as the primary form of data collection, while unobtrusive data and autoethnographic data were used to supplement and support the interview data. All interviews were conducted in Chinese, audio-recorded, and transcribed into English. All ten participants experienced harassment and discrimination related to their gender identity. Participants in the study identified two significant consequences that result from experiences of discrimination and harassment in HoK. First, it leads to decreased participation. Second, it lowers in game performance and confidence for women. All 10 participants reported some resistance to these negative experiences. These forms of resistance and coping took many forms, such as 1) reporting, 2) blocking and muting, 3) verbal confrontations and arguments, 4) teaming up with friends, 5) gender swapping, and 6) mutual support among women players. Based on this research, seven main strategies for creating meaningful change in HoK are also proposed.
  • Honesty-Humility and Economic Games: The Role of Power

    Christopher, Rachel; Department of Psychology
    Antisocial behaviours are related to certain personality constructs, such as low Honesty- Humility, as well as high levels of perceived power. However, Honesty-Humility, power, and behaviour (examined using economic games specifically) have yet to be examined in combination. I therefore examined the intersection of personality, performance on economic games and the influence of power to better understand these interactions. I used an experimental design with103 first-year undergraduate students who were randomly assigned to either a powerful (permitted to use executive office chair and new desktop) or powerless (made to use old, metal stool and broken laptop) condition before playing three economic games: dictator, ultimatum, and ultimatum variation. I hypothesized that those lower in Honest-Humility (H) would allocate more points to themselves in all games but more so in the dictator game and this effect would be exacerbated in the powerful condition. While the power manipulation had no effect on point allocation regardless of score on the HEXACO personality inventory, when combined with data from a previous study (Farrell, 2018), H was significantly negatively associated with the number of points they kept to themselves in the dictator game. In the ultimatum variation game, Agreeableness (A) was significantly negatively correlated with points allocated to self. Replicating previous findings by Farrell (2018), the dictator game significantly correlated with prior high school bullying tendencies. These findings suggest that economic games could be used as a bullying proxy to study the phenomenon in laboratory settings.
  • Synthesis and Properties of π- Extended Phenoxyl Radicals.

    Wijesundara, Maneesha; Department of Chemistry
    Phenoxyl radicals are a class of π-radicals synthesized by single-electron oxidation of phenols. The spin density from the unpaired electron of a phenoxyl radical is highest at the oxyl position, as well as at the ortho and para positions relative to the oxyl group. The stability of phenoxyl radicals can be improved by substituents at the ortho and para positions, including aromatic, O, N, S-alkyl, and sterically hindered alkyl groups, which compensate for electronic deficiency through resonance or inductive effects. In 2016, Lemaire group reported a crystal structure of the stable phenoxyl radical 2,6-bis(8-quinolylamino)-4-(tert-butyl)phenoxyl (BAQP), which lacks the commonly utilized tert-butyl groups at the ortho position relative to the oxyl group. Moreover, the BAQP radical also showed reversible π-dimerization in solution. This thesis describes the synthesis and characterization of two sets of phenoxyl radicals that lack ortho tert-butyl groups, similar to BAQP. The first set of phenoxyl radicals is ortho-substituted with amino derivatives of large aromatic π-systems, namely pyrene, naphthalene, and phenalenone. The second set is the halogenated derivatives of the BAQP radical. This thesis also explores the stability and the reversible π-dimerization of both of the above-described novel sets of phenoxyl radicals. Notably, one of the radicals synthesized during this work, 5-(tert-butyl)l-2-oxy-1,3,-bis(1- prenylamino)benzene, was proven to be stable as crystal structures were obtained from the pure compound. This particular radical, like BAQP, showed reversible π-dimerization in solution detected by spectroscopic methods such as EPR and 1H-NMR spectroscopy methods. The solid- state properties of this radical were also explored through DC susceptibility measurements and EPR spectroscopy.
  • Non-pollen palynomorphs and black carbon in sediments from Walden Pond (Massachusetts, USA): evidence of sudden onset events and human impact over the past millennium.

    Alderson, Aaron; Department of Earth Sciences
    Walden Pond (Concord, MA, USA) has long held important value from a cultural, ecological and geological perspective. It consists of three distinct subbasins where large-scale changes within the catchment and the lake are recorded in the acid-resistant organic fraction of the sediments. Palynological data from sediment cores in each of the three basins in Walden Pond record anomalous sedimentation events that can be correlated across the lake over the last 1000 years, and differences in the palynological signature of these events between sub-basins provide insights into depositional triggers. The youngest event, marked by abundant charcoal in palynological preparations, is attributed to late 19th – early 20th century CE fires, consistent with peak abundance of Ambrosia in the pollen assemblage. The non-pollen palynomorph (NPP) assemblage in this unit differs from that in the earlier three intervals of anomalous sedimentation in this deep, closed basin that pollen data help constrain to the mid- 18th, 14th–15th, and 12th–13th centuries CE, with additional potential redeposition events around 1000 CE and predating the turn of the second millennium. Earlier events are marked by increases in palynomorphs that record resedimentation from shallow parts of Walden Pond into deeper parts of the lake. The mid-18th century event is attributed to the 1755 Cape Ann Earthquake (estimated magnitude MLg 6.2 ± 0.5), supported by the first appearance of fly ash/ spheroidal carbonaceous particles (SCPs) produced by smelting of bog iron by early European settlers in the late 17th century as well as the rapid increase in Ambrosia /nonarboreal pollen (i.e., ‘agricultural weeds’) at a time of rapid population growth. Although less well constrained chronologically, the two earlier events appear to have been of even greater magnitude based on palynological and sedimentological characteristics that are consistent with seiche action in Walden Pond, and thus can be used to refine estimates of paleoseismic risk in this heavily populated region characterised by infrequent historic high magnitude earthquakes and suggestions of earlier events in oral histories.
  • Is It Better to Be Known?: Understanding the Vulnerability of Autistic Individuals in Registry-based Programs Used by Police Services in Ontario, Canada

    Whittingham, Lisa; Department of Child and Youth Studies
    Registry-based programs have been adopted by many police services in Ontario, Canada, as a voluntary opportunity for vulnerable persons or their caregivers to provide personal information to police in case of crisis or emergency. The overall goal of this dissertation was to provide a foundational understanding of these programs using a grounded theory methodology. This dissertation is comprised of three separate studies that reflect the different forms of grounded theory coding. Study one explored the programs promoted on official police service websites in Ontario, Canada, using inductive qualitative content analysis. This content analysis revealed that sampled police services promote four programs on their websites to address encounters between police and autistic individuals. By examining the content of these programs, it was determined that autistic individuals are labelled vulnerable persons due to the perceived relationship between inherent autistic traits and behaviours and the risk of harm or victimisation when they are without the supervision of a caregiver. Study two analysed a subset of the programs promoted on official police services websites, Autism Registries, using the What is the Problem Represented to Be? framework for discourse analysis. From this analysis, the suggested problem solved by Autism Registries is the risk of harm and victimisation resulting from autistic traits and behaviour. Constructing autistic individuals this way in the materials for the Autism Registries reproduces ableist discourses, which suggest that these individuals are incapable of risk management and, therefore, should be relegated to the care of others. It also obscures the contributions of broader social conditions contributing to encounters between police and autistic individuals. Finally, in Study three, officers from seven police services across Ontario, Canada, were interviewed to understand how they conceptualised the vulnerability of autistic individuals and the role registry-based programs played in their encounters with them. Sampled police officers recognised that the vulnerability of autistic individuals was complex and resulted from multiple contributing variables. They described how registry-based programs could be used for search and rescue operations, navigating encounters requiring de-escalation, and justifying accommodations made to policies and procedures. Combined, the results from these studies suggest that registry-based programs in police services can benefit both officers and autistic individuals during crisis encounters; however, by focusing on these encounters, the broader social conditions that are contributing to elevated police contact in the first place are left unexamined and unaddressed. This includes ableist assumptions that contribute to stigma and discrimination towards autistic individuals and the austere government spending that has left the gaps in service for police to fill.
  • Improving Lung Cancer Risk Prediction: Integration of Novel Predictors and Modelling Using Machine Learning Random Forest versus the Validated PLCOm2012 Logistic Regression Model

    Malik, Aleeza; Applied Health Sciences Program
    Lung cancer (LC) is the leading cause of cancer-related deaths among men, and the second most common cause of cancer death among women, worldwide. Symptoms of LC appear when the disease has progressed to an advanced stage when curative treatments are ineffective, leading to poor prognosis. LC screening using low-dose computed tomography is shown to be effective for early detection of LC to reduce LC mortality. The goal of this study was to develop a superior LC risk prediction model compared to the current established Prostate, Lung, Colorectal, Ovarian Cancer Screening Trial 2012 model (PLCOm2012) for selection of high-risk individuals for LC screening. Development of the risk models was done using data from the Prostate, Lung, Colorectal, Ovarian (PLCO) Cancer Screening Trial control arm (n=43,217) and validated using the PLCO intervention arm (n=42,493). Logistic regression (LR), and random forest (RF) methodology were analyzed using R software. The models were evaluated based on their ability to predict 6-year LC risk and assessed using predictive performance measures including discrimination and calibration. Results of the current study indicated a superior predictive performance of the PLCOm2012 LR model compared to the risk model developed using RF, with area under the receiving-operating characteristic curve (ROC-AUC) of 0.797 and 0.775 (p<0.001), respectively. The addition of supplemental β-carotene, dietary vitamin A, total isoflavone, and history of chest x-ray also resulted in an increase in ROC-AUC from 0.797 to 0.810 (ΔROC-AUC= 0.013, p<0.001). This study demonstrated that the application of traditional LR exhibited superior predictive performance in comparison to the advanced machine learning RF technique. Moreover, the incorporation of dietary variables and history of chest x-ray improved the predictive performance of the current standard PLCOm2012 model.
  • Towards the total synthesis of semi-synthetic opiate species and presilphiperfolan-1-ol.

    Wicks, Christopher; Department of Chemistry
    The synthesis of 10-keto opiates is underscored by the urgent need of novel κ-selective opioid agonists that offer comparable analgesic effects to their alkaloid precursors while limiting the risks of physical dependency. While there have been multiple syntheses of oxycodone reported, there has been only one total synthesis of 10-keto-oxycodone to date. Inspired by previous work from the Fukuyama group we investigated a functional group-based approach to oxycodone and 10-keto-oxycodone highlighted by a key oxidative dearomatization step. Efforts made towards this end with be discussed herein. Presilphiperfolanols constitute a family of sesquiterpenes that can undergo further rearrangement to afford a diverse array of terpenoid skeletons due to the ring strain that is inherent to their carbocyclic framework. This structurally complex family of natural products is unique owing to their highly compact tricyclo[,11]undecane sesquiterpene skeleton that bears five contiguous stereocenters, two all-carbon quaternary centers, and a tertiary hydroxy group. To date, only three natural presilphiperfolanols have been isolated: presilphiperfolan-1β-ol, presilphiperfolan-8α-ol, and presilphiperfolan-9α-ol. In addition to being important biosynthetic precursors, these natural products have also been found to exhibit antimicrobial activity and insecticidal properties. Of particular interest is presilphiperfolan-1β-ol, which has been previously synthesized by Stoltz in the first asymmetric synthesis of a presilphiperfolanol, and subsequently by Tiefenbacher in a semi-synthesis involving supramolecular catalysis. Unlike the approaches by Stoltz and Tiefenbacher, our group has discovered a highly efficient tandem gold (I) catalyzed 5-exo-dig and formal [4+2] cyclization that affords direct access to this tricyclo[,11]undecane sesquiterpene skeleton. This method has the added benefit of generating 3 of the 5 requisite stereocenters found within the target in a single transformation. Efforts towards the completion of the total synthesis of presilphiperfolan-1-ol will be discussed herein. Experimental and spectral data are provided for all newly synthesized compounds.
  • The Socio-Legal Regulation of BDSM in Canada

    Adams, Zoe; Department of Sociology
    This research examines Canadian case law and the lived experiences of BDSM practitioners articulated on the blog Reddit, using critical discourse analysis in order to understand: (i) How is BDSM framed in legal discourse? (ii) To what extent do dominant discourses produce a criminalised sexual subjectivity for BDSM practitioners? (iii) What interpretive repertoires do BDSM participants in different social locations (e.g., race, class, gender, disability) employ to describe their experiences negotiating consent? (iv) How might an analysis of people’s perspectives and policy arguments contribute to public and scholarly debates by recognizing the social value of BDSM practice? The findings illustrate several discourses, which are categorised by those found within case law data and Reddit data. The discourses found in case law include: Moral custodianship, deviance as a social contagion, biopolitical sexual regulation, state paternalism, and sexual citizenship. The discourses located within Reddit data include: Social-sexual dynamics and hierarchies, self-empowerment/confidence and self-worth, visibility of kink, consent/choice, pleasure/eroticism in kink, and counter-hegemonic pleasures/identities. The distinctions between discursive categories are often blurred as many adjudications and Reddit posts draw from multiple discursive narratives in the appeal for legal action against BDSM-related activities, and the narratives of personal experiences within BDSM communities. Consent, as a concept and practice, is present in Canadian case law and the narratives of BDSM community members within this study. Particularly, this research investigates the nuances of consent, its fluidity, and what consent means in the language of the law as compared to the practices of consent within BDSM-related encounters. Through the narratives of BDSM community members on Reddit, bloggers voice and resist dominant socio-legal discourses that frame their non-normative sexualities as immoral, deviant, and ultimately, criminal. Giving voice to BDSM practitioners contributes to a greater understanding of consent. The corollary of this research is the possibility of utilising the expert knowledge of BDSM community members in differentiating between consented BDSM play and willful sexual assault.

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