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Synthesis and Reactivity of Diimino-N-Heterocyclic Carbene Supported Tetrylones
Get PDFThe work described in this thesis is focused on the preparation of a series of novel tetrylones stabilized by diimino-N-heterocyclic carbene followed by studies on their reactivity.
In the pursuit of dimNHC-supported stannylone III-6, attempts to isolate free dimNHC ligand IV-19 before its reaction with a tin reagent proved challenging. Conventional deprotonation of imidazolium salt III-7 led to undesired rearrangement product III-10. Facing difficulties in isolating free dimNHC III-8, alternative routes were explored. An effective solution involved using bis(trimethylsilyl)amido chlorotin(II), SnCl[N(SiMe3)2], which generated dimNHC ligand III-8 in-situ. This process simultaneously incorporated the (Sn+-Cl) fragment at the central carbene position, forming cationic stannylene III-14. The subsequent reduction of III-14 with excess potassium graphite resulted in the desired stannylone III-6.
The reactivity studies of dimNHC-supported germylone IV-6 were expanded. Germylone IV-6 reacts with azides N3R (R=SiMe3 or p-tolyl) to furnish the first examples of germanium π-complexes IV-10 and IV-11. Reaction of IV-10 with tetrachloro-o-benzoquinone results in the net transfer of a germanium atom and formation of the free diimino-guanidine ligand IV-13.
Germylone IV-6 reacts with B(C6F5)3 to give the zwitterionic borate V-7. This compound can be converted into the hydroborate V-8 and further into germylene-borane V-4. Compound V-4 is a Ge/B analogue of Stephan’s FLP parent P/B compound (C6H2Me3)2P-C6F4-B(C6F5)2 but unlike the latter cannot split dihydrogen. Moreover, attempts to prepare a Ge/B analogue of the zwitterion (C6H2Me3)2HP-C6F4-BH(C6F5)2 by protonation of borate V-8 resulted in immediate elimination of H2.
A synthetic approach for dimNHC-supported silylone VI-9 involved utilizing the adduct of dimNHC with ZnCl2 VI-11. The adduct VI-11 was prepared by trapping the in-situ formed dimNHC IV-19 with a Lewis acid (ZnCl2). Subsequent exchange between the dimNHC →ZnCl2 adduct VI-11 and the IPr→SiCl2 silylene VI-12 resulted in the formation of the novel dimNHC-supported silylene VI-13. Finally, VI-13 was successfully reduced to yield the desired dimNHC-supported silylone VI-9.
Later, we found that dimNHC IV-19 could be directly prepared from imidazolium salt VI-10 by deprotonation with IPr, serving as a Lewis acid-free base. IV-19 is the first isolable diimino carbene. Upon heating IV-19 in toluene, it cleanly converted to the aromatic C-C bond activation product IV-17. With dimNHC IV-19, we established an alternative synthetic route to silylone VI-9 using ligand IV-19 and HSiCl3 as starting reagents
Investigating Postsynaptic Effects of a Drosophila Neuropeptide on Muscle Contraction
Get PDFSupplementary figures for J Neurophysiol 131: 137–151, 2024. First published December 27, 2023; doi:10.1152/jn.00246.2023.Neuropeptides play key physiological roles by acting as transmitters or hormones that modulate chemical synapses, but distinguishing presynaptic and postsynaptic effects can be challenging. The Drosophila neuropeptide, DPKQDFMRFamide, was previously shown to enhance excitatory junctional potentials (EJPs) and muscle contraction by presynaptic and postsynaptic actions. Here, postsynaptic actions of the peptide were investigated by examining how it modulates effects of the excitatory neurotransmitter L-glutamate on muscles of 3rd instar larvae after removing the central nervous system. DPKQDFMRFamide enhanced glutamate-evoked contractions with at low concentrations (EC50 1.3 nM), consistent with its role as a neurohormone, and the combined effect of both substances was more than additive. Glutamate-evoked contractions were also enhanced when transmitter release was blocked in temperature-sensitive mutants. The peptide increased membrane depolarization in muscle cells when co-applied with glutamate, and its effects were blocked by nifedipine, an L-type channel blocker, indicating actions at the plasma membrane and involving calcium influx. DPKQDFMRFamide also enhanced contractions induced by caffeine in the absence of extracellular calcium, suggesting increased calcium release from the sarcoplasmic reticulum (SR) or effects downstream of calcium release from the SR. The peptide’s effects do not appear to involve calcium/calmodulin-dependent protein kinase II (CaMKII), previously shown to mediate presynaptic effects. The approach used here might be useful for examining postsynaptic effects of neurohormones and cotransmitters in other systems.NSERC 4629
Ending the cycle: Scholars' perspectives on hazing prevention
Get PDFThe purpose of this study is to synthesize the knowledge of hazing experts to explore hazing prevention techniques. Preventing hazing in sport has been studied, analyzed, and explored through various research designs centered on strategies of athlete education, cultural change, and replacement activities. However, literature has lacked a study that compares and integrates these methods within the practice of prevention. This study begins to conceptually fill that void. To critically examine, compare, and integrate hazing prevention methods, published hazing scholars were surveyed using the Delphi technique. All participants had published at least one peer-reviewed publication on hazing written in English. Using the Delphi technique, participants were surveyed three times, with each iteration being developed from the results of the previous survey. The first survey had fifteen participants, the second had fourteen, and the third had eleven. The survey responses were analyzed using thematic coding. Participating scholars provided detailed descriptions of best practices with prevention strategies centered on athlete education, cultural change, and replacement activities. Importantly, participating scholars identified that all hazing prevention methods should be implemented as much as possible as they are often connected, interrelated, and have the potential to be most effective when utilized together
Beatties Stationary Fonds, 1836-2014, n.d.
Get PDFBeatties Stationary Limited was originally founded in 1860 by Mr. D.W. Bixby and Mr. P. Izzard. At the time it was known as “Izzard & Bixby Booksellers and Stationers” and was located in downtown St. Catharines. In 1864 Izzard left the business and Bixby became the sole proprietor. The business was now known as D.W. Bixby Books and Stationary and moved to 12 Ontario Street. When Bixby died in 1908, his widow took over the business and moved to 124 St. Paul Street a few years later. Mrs. Bixby hired Lawrence Beattie as a delivery boy and many years later Beattie purchased the business from her.
Eventually the business changed its name to Bixby-Beattie Company and moved to 136 St. Paul Street. By 1948 another significant change occurred when the business was incorporated with Lawrence Beattie as President, Lloyd Hill as Vice-President and Kathleen Everest as Secretary-Treasurer. At this point the name was changed to Beattie-Hill Ltd. When Hill left the business in 1955 the name changed once again and was now known as Beattie Stationary Limited. Lawrence had an avid interest in books and he implemented a lending library in the store.
By 1968 Lawrence’s nephew Rodger Beattie took over as President after purchasing a controlling interest in the company. He remained as President until 1992 and the business saw significant expansion under his leadership. The first branch store was opened in 1968 in the Grantham Plaza in St. Catharines, another in Fort Erie in 1971, one in Welland in 1976, and one in Niagara Falls in 1980. He also spearheaded the effort to found and organize the Basics Group. This was a group of independently-owned office supply dealers from across Canada that was founded so that the collective members could benefit from the marketing and buying power of the group. In 1978 Beatties moved from St. Paul Street in St. Catharines to a larger facility on Queen Street, which served as the head office and main store, and underwent major renovations in 1989.
Company leadership changed again in 1994 when Lawrence Beattie’s grandson Ted Hoxie purchased company shares and became President. Over the years Hoxie purchased additional shares and by 2004 had full ownership of the company. In 2006 Beatties consolidated some of its operations into a building on Vansickle Road in St. Catharines, which served as a distribution centre, retail store, showroom, and head office. In 2010 the company celebrated its 150th anniversary. A major change to the company occurred on August 1, 2023 when Staples Professional purchased Beatties. Under the terms of the sale, the company will continue to operate independently under its current president, Brad Steeves, and leadership team, and retains the Beatties banner.Fonds contains material related to the activities of Niagara-based office-supply business Beatties. The company has operated under several names over the year including Izzard and Bixby Booksellers and Stationers, D.W. Bixby Books and Stationary, Bixby-Beattie Company, Beattie-Hill Ltd., Beattie Stationary Ltd. and Beatties. In addition to selling stationary, the store also had a lending library at one point. Numerous books are included in the fonds, as well as material related to the company’s operations and expansion including catalogues, promotional material, photographs, administrative records, and branded items. Some information about the Beatties family is also included, as well as several historic St. Catharines newspapers from the 1860s and 1870s that feature early advertisements for the business
Essex Register, November 16, 1814
Get PDFThe Treaty of Ghent ended the War of 1812 between the United States and Great Britain, which was largely fought in the British colony of Canada. Peace negotiations began in Ghent in August 1814 but an agreement was not reached until December 24, 1814. The agreement essentially restored the status quo for both countries. The Treaty of Ghent was ratified in February 1815.An issue of the Essex Register dated November 16, 1814 featuring a map of the Great Lakes and of the North Western Territory with an extensive article on the negotiations to end the War of 1812 and how this may affect the boundary between Canada and the United States. The article title reads “Don’t Give up the Soil: England demands of us Two Hundred & Twenty Millions of Acres!” The article fills the first page and begins “We have very carefully examined the Communications from our respectable Envoys at Ghent, and have particularly noticed the demands of the enemy. It appears they want a new boundary line. It will be very well to understand this new proposed boundary line distinctly. To enable our readers to have a view on the whole ground we present them with a “Map of the Lakes”, and the territory connected with them”. The article proceeds to outline proposed boundary changes that the writer feels are unfair and concludes “We are not prepared for this degradation…we invoke the spirit of Washington to inspire our countrymen with wisdom, courage and patriotism to resist such infernal propositions. We must wage an interminable war with the plunderers of the world, rather than submit to such infamous demands.
Examining the Characteristics of Interventions Targeting Mental Health Stigma among Athletes: A Systematic Review
Get PDFResearchers’ interest in mental health stigma (MHS) in sport has increased given its prominence as a barrier to help-seeking. Yet, despite existing interventions, the evidence base targeting reductions in MHS in athletes is equivocal. The purpose of this systematic review is to describe the core components of interventions developed to target MHS in athletes. Pre-registered on PROSPERO (CRD42023470267), the review adheres to PRISMA guidelines. Inclusion criteria were: 1) Studies focusing on interventions targeting MHS delivered exclusively to athletes regardless of age or competitive level; 2) Quasi-experimental, or randomized control trials and 3) articles published in English. A comprehensive keyword search across six databases (PsycINFO, MEDLINE via PubMed, CINAHL, Proquest Nursing and Allied Health, SPORTDiscus, and Web of Science) yielded 665 studies for screening, with seven meeting inclusion criteria including nine interventions. Methodological quality was assessed via the Quality Assessment Tool for Quantitative Studies or the Cochrane Collaboration tool depending on study design. Across retained studies, general study details and sample characteristics were coded. The TIDieR checklist was used to detail intervention reporting with enrichments recommended by Clay et al. (2020) MHS intervention framework. MHS intervention components were coded by two independent reviewers. Results indicated that while certain aspects of intervention reporting, such as procedures, were consistently well-documented, deficiencies existed in the other items like reporting fidelity, modifications, and tailoring/cultural adaptation. The discussion highlights the significance of providing a complete description of the intervention's components, which may make it easier for future researchers to replicate, implement, and disseminate research findings in the context of knowledge mobilization. While the current review offers a unique focus on MHS in athletes, it has limitations to consider, including a narrow search focused on English studies, missing data retrieval, and the TIDieR checklist's limited assessment of intervention quality and effectiveness. These limitations call for careful interpretation of the review's findings and highlight areas for improvement in future research. The authors did not receive any funding from any organization for the current review
Goldspink Prints Collection, 1755-1877, n.d.
Get PDFThe collection contains six prints and three maps. The prints mostly depict various battles and skirmishes during the War of 1812 including the Battle of Queenston, Perry’s victory on Lake Erie, and the attack on Fort Oswego. The maps include one of Canada West and two of Lincoln and Welland Counties.Brothers Tom and Frank Goldspink spent many years amassing a large collection of Niagara-related artwork. Since 2006, the art was displayed in the TAG Art Gallery in St. Catharines. The closure of the gallery in 2022 meant that a new home needed to be found for the collection. The art was distributed among various institutions in the Niagara Region including Brock University, the Niagara Falls History Museum, the St. Catharines Museum, and the Niagara-on-the-Lake Museum
The New Frontier of Academic Integrity: Postplagiarism & its Implications
Get PDFKeynote address at the Manitoba Academic Integrity Network Speaker Series
Travel diary of Marguerite Treet “New York to Frisco and Back”, 1919
Get PDFA travel diary belonging to Marguerite Treet of Hackensack, New Jersey, describing her trip from New York to San Francisco and back in 1919. The entries are dated from July 7, 1919 to November 18, 1919 and include descriptions of her activities, accommodations, sightseeing, meals, people she meets, and the state of her car. The trip takes her through Pennsylvania, Ohio, Indiana, Wisconsin, Minnesota, North Dakota, Montana, Wyoming, Idaho, Washington, then up to Alaska, back down to Oregon, and California, before heading back east through Arizona, New Mexico, Colorado, Kansas, Missouri, West Virginia, and Maryland.
The first few days of her trip take her from New York to Niagara Falls
Investigating the Cellular Responses of Cancer Cells to Physiological and Hypoxic Oxygen Conditions
Get PDFMost incubators used in cell culture do not regulate O2 levels, making the headspace O2 concentration ~18%. In contrast, most human tissues are exposed to 2–9% O2 in vivo (physioxia). The main goal of this thesis project was to gain a better understanding of how supraphysiological O2 levels affect cell behavior in vitro, with a focus on cancer cell biology. Using RNA-seq, I studied how culture in either 5% O2 or 18% O2 affects gene expression in four human cancer cells. I found that O2 level in culture affected hundreds of genes, however, in a largely cell-type specific manner. Further, gene targets of the hypoxia-inducible factors (HIFs) were upregulated at 5% O2 compared to 18% O2 in all cell lines. This led me to investigate how culturing cancer cells at a baseline level of 5% O2 or 18% O2 affects their response to hypoxia (here, 1.1% O2). My results indicate that baseline O2 level substantially affects the transcriptional response of prostate cancer cells (PC-3) to hypoxia. Notably, cells grown in 18% O2 and then exposed to hypoxia showed an enhanced induction of HIF-regulated genes, particularly genes involved in glucose metabolism. This in turn resulted in an enhanced glucose uptake rate of cells taken from 18% O2 to hypoxia, compared to cells preadapted to 5% O2 and then exposed to hypoxia. Finally, while acute hypoxia did not affect proliferation or migration of PC-3 cells regardless of their baseline O2 level, cells preadapted to 5% O2 did show higher proliferation and migration rates compared to cells in 18% O2. We conclude that O2 levels in culture affect gene expression, glucose consumption, and growth in cancer cells, which, in turn, might result in differential sensitivity towards anticancer drugs, highlighting the importance of maintaining physiological O2 conditions in cell culture