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Synthesis of xanthene derivatives from salicylaldehydes, phenols and aryl-boronic acids
No full textThe Petasis reaction, a boronic acid-Mannich variant, involves the reaction of an amine, an aldehyde and a boronic acid.By employing arylboronic acids, salicylaldehydes, and replacing the amine component of the Petasis reaction with 2-naphthol, it was found that a xanthene skeleton is produced, which can then undergo intramolecular dehydration to produce a benzoxanthene derivative. The reaction required a Lewis acid catalyst, namely copper (II) triflate under microwave heating conditions.1In order to optimize the reaction conditions, and study the substrate scope by making analogs, this study was undertaken. Initially the reaction was performed in DMF, but after testing the reaction with 1-methyl-2-pyrrolidinone and 1,2-dimethoxyethane, the latter was found to give the better yield. The use of microwave irradiation was also optimized, with the best yield occurring under conditions of 150 oC for 20 minutes. Ther presence of product was confirmed by the formation of a faster moving spot than all starting materials on the TLC plate. Column chromatography was used to purify the product. Melting point ranges were collected, and products were characterized using 1H and 13C NMR spectroscopy. A total of 6 xanthenes were synthesized in yields ranging between 13% and 38%.</p
Molecular characterization of the PEP A (CNDP2) gene in masked shrews (Sorex cinereus) on Bon Portage Island
No full textThe population of Sorex cinereus (masked shrews) on Bon Portage Island, N.S., exhibits a high frequency of a unique allele in the CNDP2 gene, which encodes the enzyme cytosolic nonspecific dipeptidase (CNDP2). These shrews feed primarily on amphipod crustaceans, such as Platorchestia platensis, a unique dietary characteristic of this population. It has been hypothesized that the high frequency of this CNDP2 allele may be an adaptation to the specific dietary pressures associated with consuming marine invertebrates. The aim of this project was to analyze the CNDP2 gene sequence in BPI shrews and compare it to mainland populations. The gene sequences for CNDP2 were obtained from Ms. Marie-Laurence Cossette, a PhD candidate at Trent University, who sequenced the gene. Known CNDP2 sequences from related species were retrieved from the GenBank database for alignment and comparative analysis. The sequence data were compared between BPI and mainland populations, revealing a unique mutation at position 278 (Glu → Lys) in BPI shrews, which was not present in mainland populations. Bioinformatics analyses showed that this mutation did not significantly affect the enzyme’s substrate-binding ability, though it slightly reduced protein stability when compared to mainland variant. The GAG → AAG (Glu → Lys) mutation may be linked to oxidative stress in the BPI environment, caused by the consumption of marine invertebrates like amphipods. These prey experience oxidative stress in their intertidal habitats, and the shrews may ingest oxidative metabolites, leading to DNA damage, such as guanine alkylation and mispairing during replication, potentially causing the mutation. The high frequency of the Lys278 allele in BPI shrews could also be a result of genetic drift or a mild adaptive advantage related to their unique diet. Further studies are needed to confirm the functional implications of this mutation. This research provides insights into the molecular adaptations of isolated populations in response to ecological pressures and dietary specialization.</p
Investigating the anti-breast cancer potential of novel derivatives of Mastoparan
No full textNovel cancer therapeutics should aim to impede drug resistance by offering new mechanisms of action, while increasing specificity toward transformed cells more than normal cells. Mastoparan, an anti-cancer peptide derived from wasp venom, has shown potential to meet these criteria. Mastoparan utilizes a mechanism of action that does not rely on molecular markers allowing for the target of triple negative breast cancer cells while minimizing resistance. In this study, the biological activity of Mastoparan peptides with altered amino acid sequences were investigated and referred to as derivatives. Mastoparan derivatives (D20 and D64) were found to significantly decrease the percent metabolic activity of the MDA-MB-468 cell line within 24 h (10 μM) at lower concentrations than Mastoparan (25μM). The MDA-MB-468 cell line showed significantly decreased cell viability within 10 min of exposure to 25 μM of D20 and D64, and 50 μM of Mastoparan. Flow cytometry provided strong evidence of membrane lysis, as propidium iodide entered the cell due to the impairment of the cellular membrane within 10 min. HCC1806 tumour spheroids grown for seven days showed a change in morphology when exposed to Mastoparan and Mastoparan derivatives (30 μM) for three days identified by undefined margins and cellular debris. Image J analysis showed tumour spheroid circularity was significantly decreased by D64, likely indicating damage to the tumour spheroid margin. As hypothesized Mastoparan D20 and D64 show promising potential as novel cancer therapeutics, displaying more anti-breast cancer potential than Mastoparan.</p
Quantitative analysis of nanoparticles by single particle-inductively coupled plasma-mass spectrometry (sp-ICP-MS)
No full textSingle particle-inductively coupled plasma-mass spectrometry (sp-ICP-MS) was evaluated as a method for accurately measuring nanoparticle concentrations and size distributions. Traditional methods, such as transmission electron microscopy (TEM), high resolution scanning electron microscopy (SEM), dynamic light scattering (DLS), ultrafiltration, and field-flow fractionation are time-consuming and lack element specificity. Using sp-ICP-MS, gold nanoparticle standards of 10 nm, 40 nm, and 80 nm were measured with high accuracy. Mean particle sizes were determined to be 11 ± 2 nm, 45 ± 9 nm, and 82 ± 9 nm, with the standard deviations reflecting the width of the size distribution and confirming the uniformity of particle sizes for each standard. Complex mixtures containing multiple sizes of gold nanoparticles were also quantified, showcasing the technique’s capability for characterizing heterogeneous samples with accuracy. To further evaluate the method, lab-synthesized gold nanoparticles were analyzed to simulate more realistic and polydisperse samples. Additionally, silver nanoparticles were successfully measured using the same calibration method, demonstrating the versatility of sp-ICP-MS for different nanoparticle compositions. The measured parameters include particle size, size distribution, size standard deviation, particle concentration, and total number of particles analyzed. These results establish sp-ICP-MS as a rapid, robust tool for nanoparticle analysis, offering significant advantages over traditional methods and expanding its potential applications in environmental monitoring.</p
Measuring gender in studies of youth's mental health: a rapid review
No full textSex differences in risk for developing different mental health disorders are well established. However, recent literature suggests that differences in gender may underlie these observed differences. Despite developments in the social and scientific understanding of gender—such as the American Psychological Association’s (APA) Inclusive Language Guide—it is unclear whether gender is being measured consistently in mental health research with youth. I conducted a rapid review to assess how gender has been conceptualised and measured in youth mental health research since the publication of the APA’s Inclusive Language Guide. A systematic search of two relevant databases produced 4,039 results. Of the initial results, 230 studies were included in the final review. Thirty percent of the 230 included studies did not clearly report how they measured gender. Of the studies that did report how gender was measured, 58% used a binary gender measure. Finally, 75% of the 230 included studies relied on outdated conceptualisations of gender, failing to meet the APA’s Inclusive Language Guide. These results provide context about how gender in the youth mental health literature, informing researchers and policy makers and provides evidence that further efforts are required to improve the measurement of gender. Given the majority of included studies measured gender in a reductive manner, opportunities to more accurately measure gender while minimizing researcher and participant burden are discussed.Keywords: gender, measurement, youth, mental health, systematic review</p
Great harbour
No full textThis creative writing thesis Great Harbour is a short story cycle that explores the relationship between people and place. The cycle consists of four short stories and follows a group of four young roommates living in Halifax, Nova Scotia. Each of the stories focuses in on one of the main characters and their experiences with a different piece of Halifax architecture. The stories are titled in accordance with the architectural style of the featured building: “Brutalist” features the Killam Memorial Library, “Palladian” features Saint Paul’s Anglican Church, “Folk” features the Maud Lewis House in the Art Gallery of Nova Scotia, and “Eclectic” features a fictional house that is inspired by the Victorian Eclectic style houses on Tower Road. In addition to focusing on structures, his thesis explores the important role that camaraderie plays in establishing home. The architecture allows the characters to find their place in the broader community, to strengthen their friendships with one another, and to discover that “home” can be found anywhere. The title Great Harbour is the English translation of Kjipuktuk, the Mi’kmaq word for Halifax. The word “harbour” is derived from the Old English word herebeorg, meaning “shelter or refuge” and, in addition to being a tribute to the Halifax harbour, reflects the community of stories, buildings, and people who are brought together in this cycle.</p
Identifying alternative biomarkers of stress in the Leach’s Storm-Petrel (Oceanodroma leucohora)
No full textGlobally, Leach’s Storm Petrel (Oceanodroma leucohora, hereafter LHSP) populations have been steadily declining, and although specific reasons for declines are still unknown, there are many hypotheses such as predation, habitat destruction, contaminants, climate change, among others. Biomarkers can be and are used to detect and quantify potential stress responses to stimuli. Specifically, in LHSP, there has been relatively little biomarker research done, but it is an important area of study, because it could help our understanding of how stress in the environment affects them. Blood samples were taken from 13 adult LHSP on Bon Portage Island, Nova Scotia. Four of those samples were later lost, so in total 9 samples were used in this observational study. SDS-PAGE was used to separate proteins in each sample. A ChemiDoc MP Imaging system was used to image the gel, and proteins in gels were compared to a known standard. Prominent bands were seen at 250, 150, 60, and 50 kDa with the exception of column 9 which did not run correctly during SDS-PAGE. Bands of interest that were chosen for further analysis were at 60, 37, and 20 kDa, they were either not found in all samples or were deemed unusual. There is very little research on biomarker identification and analysis in LHSP, this study will provide a good starting point for future molecular research on this species. The more research that is done on this, the more gaps of knowledge can be filled in with regards to the declining LHSP population and possibly even what can be done to mitigate this problem.</p
A comparative study of generative AI and traditional machine learning for cyber-attack detection in VANETs
No full textVehicular Ad Hoc Networks (VANETs) are considered extremely important section of intelligent transportation system because they enable communication between infrastructure and vehicles for enhancing road safety, and efficiency. As the connectivity level increases between vehicle and infrastructure, then networks are also exposed to growing number of sophisticated cyberattacks particularly zero-day attacks that pose significant threat. The use of Traditional Machine Learning (ML) models can only detect known cybersecurity attacks and face problems in identifying unseen and novel threats. Based on this, the research will explore in detail about the potential of GenAI models like variational autoencoders, generative adversarial networks, and diffusion models for detecting unseen cyberattacks in vehicular networks. A detail comparison of GenAI models and traditional ML was conducted by focusing on detection rates, accuracy, robustness to zero-day attacks, and false positives and negatives. The results showed that Hybrid models by combining ML and GenAI outperformed standalone approaches and achieve high resilience and accuracy. Besides vital advantages of GenAI, some challenges are also discussed in detail like data availability, computational complexity, and adversarial vulnerability. The study concludes through outlining the contribution, limitations, and future research work for enhancing cybersecurity in VANETs through GenAI models.</p
Quantification of mercury accumulation in three shark species and the use of science communication to foster collaborative networks for girls+ in STEM
No full textMercury (Hg) is a persistent environmental contaminant that poses significant risks to both marine ecosystems and human health. Mercury primarily enters the environment through anthropogenic activities, including industrial emissions, agricultural runoff, and improper waste disposal. Once in aquatic systems, mercury undergoes methylation, converting into methylmercury (MeHg), a highly toxic compound that is rapidly absorbed and bioaccumulates in aquatic organisms. Marine apex predators, particularly sharks, are at significant risk for elevated mercury concentrations due to biomagnification within food webs. The current study investigates the bioaccumulation and biomagnification of total mercury (THg) in muscle tissue from three ecologically, commercially, and recreationally important shark species: blacktip shark Carcharhinus limbatus (Valenciennes, 1839), blacknose shark Carcharhinus acronotus (Poey, 1860), and bonnethead Sphyrna tiburo (Linnaeus, 1758), in South Florida. The relationship and influence of shark size, trophic position, and maternal offloading on mercury concentrations was evaluated across these species. Findings indicated a positive correlation between shark size and mercury concentrations, larger individuals accumulating mercury faster than they can eliminate it, thereby placing them at higher risk for mercury toxicity. Species-specific differences were also observed, with blacktip sharks exhibiting the highest THg concentrations, followed by blacknose sharks, and bonnetheads having the lowest levels. Maternal offloading was identified as a significant pathway for elevating mercury levels in embryos and neonates, with blacknose sharks showing a higher degree of maternal transfer compared to bonnetheads. Neonate blacktip sharks, less than a few months old, exhibited mercury levels that surpassed both the health thresholds for sharks and the safety limits for human consumption; highlighting the critical need for ongoing monitoring of mercury contamination in marine apex predators and the necessity of assessing the broader ecological and public health implications of mercury exposure. The current study’s findings on mercury accumulation in sharks directly informed the development of targeted STEM education programs, grounding outreach efforts in current, real-world research. By integrating scientific data into hands-on learning experiences, the programs provided participants with a deeper understanding of environmental challenges and the real-world impact of marine contaminants. This work illustrates the importance of bridging scientific research within academic communities with broader public engagement through science communication—particularly when addressing issues with direct human health implications. In collaboration with the Terranaut Club, two shark-focused programs were developed and implemented for Girls+ aged 9–18. These immersive programs featured activities such as shark tagging, fish dissections, and workshops on conservation and pollutants in the environment. Each designed to connect participants with marine science in tangible and meaningful way. The findings from these programs, along with broader Terranaut Club initiatives, highlight the value of early exposure to science and scientific role models for underrepresented groups. The presence of female and gender-diverse role models played a pivotal role in boosting participants’ confidence and sparking interest in STEM fields. By fostering inclusive learning environments and promoting visibility in traditionally male-dominated disciplines, these programs helped cultivate the next generation of conservation scientists while raising awareness of mercury contamination and its ecological consequences.</p
Cooling of p-caterpillars
No full textGraph cooling is a process of discrete rounds which begins by choosing a vertex to cool. In the next round, the cooling spreads to all neighbours of a cooled vertex and another vertex is chosen. The process terminates when all vertices are cooled. The objective of graph cooling is to maximize the number of rounds in which the process can be performed. The maximum number of rounds is called the cooling number. This thesis focuses on the cooling number of p-caterpillars, beginning with caterpillars composed of only a path and leaves before moving on to lobsters and then p-caterpillars generally. The thesis also includes results for lexicographic products of graphs, sunlet graphs, kites, and graphs which achieve the upper bound for cooling numbers.</p