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Exploring the potential of an organometallic dendrimer in materials science and biological applications
No full textIn this research, a series of novel organometallic dendrimers were synthesized using a divergent approach, and their potential in materials science as “nanocomposites and magnetic materials” and biomedical applications were investigated. The structure of the dendrimers was confirmed by their spectral data and elemental analysis. Nine-mole ratios of nanocomposites, consisting of an organometallic dendrimer and molybdenum disulfide (MoS2), were synthesized. The mole ratio of MoS2 to the dendrimer was systematically varied from an upper limit (1:0.5) to a lower limit (1:0.002). These nanocomposites exhibited high crystallinity and showed an increase in d-spacing upon intercalation of the dendrimer molecules. The ideal condition for the preparation a crystalline monophasic system is at low dendrimer concentration, no more significant than 1:0.125 molar ratio of MoS2 to dendrimer and no lower than 1: 0.002 molar ratio, while biphasic systems were observed at a molar ratio higher than a 1:0.125 of MoS2 to the dendrimer due to dendrimer aggregation at high concentration.
The synthesized organometallic dendrimers were also investigated as a new type of precursor for the assembly of magnetic materials that contain a mixture of iron- and cobalt-phosphides phases with tunable magnetism. Electron microscopy indicated the crystalline nature of the nearly aggregated particles for both designed magnetic samples. Fe-containing homometallic dendrimers and Fe/Co-containing heterometallic dendrimers were used to develop magnetic materials containing multimetallic phosphide phases. In contrast to heterometallic samples, homometallic samples showed dendritic effects on their magnetic properties. Specifically, saturation magnetization (Ms) and coercivity (Hc) decrease as dendritic generation increases. Also, the incorporation of cobalt into the homometallic dendrimers led to markedly increases in the magnetic properties of the magnetic materials from 60 - 75 emu/g. Temperature change responses showed that heterometallic samples were less sensitive to temperature changes than homometallic dendrimers due to the presence of Co2P.
Furthermore, organometallic dendrimers were also functionalized with aspirin units in the periphery to enhance the bioavailability activity of aspirin and diminished its toxicity through successive generations of organoiron dendrimers. Furthermore, four generations of aspirin-derived dendrimers were synthesized, and their biological activity was also evaluated. All the developed complexes were tested in vitro for their antibacterial activity against Gram-positive bacteria, Bacillus subtilis (ATCC 6051), and Staphylococcus aureus (ATCC12600), Gram-negative bacteria Escherichia coli (ATCC 1175), and Klebsiella pneumoniae (ATCC10145) using agar well diffusion. An increase in the antimicrobial activity of all synthesized dendrimers with increasing generations was observed for most microorganisms. Indeed, this study reveals for the first time that organometallic dendrimers linked with aspirin show an excellent Gram-negative ability comparable to the standard drug Gentamicin. All created dendrimers were also tested for their anti-tumor activity against breast cancer cell lines (MCF-7), hepatocellular cell lines (Hep-G2), and a non-cancer cell line Human Embryonic Kidney (HEK293), utilizing the MTT cell viability assay and compared against a reference anticancer drug, Doxorubicin. Complexes G3-D9-Asp and G4-D12-Asp showed noticeable activity toward both cell lines, which were more effective than aspirin itself. Furthermore, the in vivo anti-inflammatory activity and histopathology of swollen paws were examined and displayed significant anti-inflammatory activity for all designed complexes; however, G2-D6-Asp displayed the best anti-inflammatory ability, which was stronger than the reference drug during the same period. Therefore, the functionalized organometallic dendrimer with aspirin demonstrated a significant reduction in the toxicity of aspirin on the stomach
High impact strategies to mainstreaming global citizenship education in teacher education
No full textThe forest behind the tree: Heterogeneity in how U.S. Governor’s party affects black workers
No full textIncome inequality is a distributional phenomenon. This paper examines the impact of U.S. governor’s party allegiance (Republican vs Democrat) on ethnic wage gap. A descriptive analysis of the distribution of yearly earnings of Whites and Blacks reveals a divergence in their respective shapes over time suggesting that aggregate analysis may mask important heterogeneous effects. This motivates a granular estimation of the comparative causal effect of governors’ party affiliation on labor market outcomes. This paper uses a regression discontinuity design (RDD) based on marginal electoral victories and samples of quantiles groups by wage and hours worked. Overall, the distributional causal estimations show that the vast majority of subgroups of Black workers earnings are not affected by democrat governors’ policies, suggesting the possible existence of structural factors in the labor markets that contribute to create and keep a wage trap and/or hour worked trap for most of the subgroups of Black workers. Democrat governors increase the number of hours worked of Black workers at the highest quartiles of earnings. A bivariate quantiles groups analysis shows that democrats decrease the total hours worked for Black workers who have the largest number of hours worked and earn the least. Black workers earnings more and working fewer hours than half of the sample see their number of hours worked increase under a democrat governor
The effect of rearing in a shelved environment on behavioral and physiological markers of welfare in rats (Rattus norvegicus)
No full textEarly-life experiences are critical modifiers of development. An important component of early-life experience is the nature of maternal interactions, which can be modified by stress. During rearing, mothers are typically allocated to single-level cages where they are readily accessible to pups, a potentially stressful scenario not reflective of nature. Accordingly, mothers regularly removed from the rearing environment interact differently with their offspring, leading to long-term changes in offspring physiology and behavior. Such changes commonly include modifications within the hypothalamic-pituitary-adrenal axis, of which corticosterone is a major component. Modifications in the hypothalamic-pituitary-adrenal axis may also be manifested through changes in affective behavior and assessed via tests such as the open field and elevated plus maze as well as via ultrasonic vocalization (USV) analysis. As a means of assessing the impact of rearing in a shelved environment, we allocated mothers to standard single-level cages or cages with an integrated shelf, which allowed the mother to temporarily escape pups. While there were no differences in fecal corticosterone, behavior in the elevated plus maze, or USVs, male rats reared in standard cages weighed more, and all standard single-level housed rats spent more time in the center of the open field. The observed differences indicate that allocating nursing mothers to shelved environments throughout the postnatal period has long-lasting effects on offspring behavior that must be considered when establishing dam enrichment protocols.Sir James Dunn Animal Welfare CentreAtlantic Veterinary College, University of Prince Edward Islan
Stepping up and stepping in: Exploring the role of nurses in supporting grandparents raising grandchildren
No full textThis study focused on the experiences of grandparents raising grandchildren in rural, Prince Edward Island, Canada. Termed grand-families, there are numerous reasons why grandparents must step up and step in to care for their grandchildren. Often these reasons are related to their adult children’s struggles with mental illness and substance use disorders. Adopting Clandinin and Connelly’s approach to narrative inquiry, we present findings from the conversational interviews conducted with 12 grandparents raising their grandchildren. Interview data were analyzed through the narrative dimensions of time, place, and relationship. Findings are presented as rich narratives which illuminate the evolution and storied experiences of grand-families. Particularly revealing are the challenges grandparents face as they navigate various systems, including health care, that do not acknowledge the uniqueness of their family form. Nurses work with grand-families across varied clinical settings. Grounded within the philosophy of Patient and Family Centered Care and family nursing theory, this article offers recommendations for supportive interventions that nurses can implement when caring for grand-families across clinical settings. This study has the potential to facilitate the development of evidence-based supports and services, which are responsive to the needs, realities, and complexities of grand-families.Social Sciences and Humanities Research Council of Canada Individual Partnership Engagement Gran
Living with COPD during the COVID-19 Pandemic: a phenomenological study
No full textThe coronavirus disease 2019 (COVID-19) pandemic has created a major health crisis worldwide. Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of morbidity and mortality in Prince Edward Island (PEI) and has emerged as a risk factor for COVID-19 disease severity. The purpose of this study was to explore the lived experience of Islanders living with COPD during the COVID-19 pandemic. A purposive sampling technique was used to recruit Islanders living with COPD during the COVID-19 pandemic. Participants were between the ages 55 and 76 years of age, and most identified as being female and having obtained higher education. Semi-structured interviews were completed via telephone or in person with seven participants over a one-month period using a prepared interview guide. This study was guided by Giorgi’s (2009) phenomenological, psychological research method. Interviews were audio-recorded, transcribed verbatim, and the researcher kept a detailed audit trail during the study. Giorgi’s (2009) descriptive phenomenological psychological research method provided structure for data collection and analysis. It was also used to form a description of the meaning of the participants’ experiences of living with COPD during the COVID-19 pandemic. The four constituents identified include: (a) experiencing fear and anxiety about the future related to the COVID-19 pandemic; (b) experiencing implications of loss; (c) striving for improved health and wellness; and (d) expressing concern for others. This study could empower healthcare providers and caregivers to gain a better understanding of living with COPD during the COVID-19 pandemic, which could inform future policy and program development.
Keywords: chronic obstructive pulmonary disease, COVID-19
Copper modulates heart mitochondrial H2O2 emission differently during fatty acid and pyruvate oxidation
No full textAlthough the preferred cardiac metabolic fuels are fatty acids, glucose metabolism also plays an important role. However, irrespective of substrate type, energy generation results in mitochondrial reactive oxygen species (ROS) formation. To determine if the preference of fat over carbohydrates predisposes cardiomyocytes to oxidant production, we measured total and site-specific H2O2 emission in heart mitochondria oxidizing palmitoylcarnitine or pyruvate during copper (Cu) exposure. H2O2 emission was higher during oxidation of palmitoylcarnitine compared with pyruvate. Moreover, the bulk of the H2O2 emitted during palmitoylcarnitine oxidation originated from the outer ubiquinone binding site of complex III (site IIIQo) and the flavin site of electron transfer flavoprotein (site EF). We found no evidence of ROS production from complex I ubiquinone-binding site (site IQ) by reverse electron transport during oxidation of palmitoylcarnitine. Pyruvate oxidation also drove H2O2 emission primarily from sites IIIQo; however, the flavin sites of pyruvate dehydrogenase (site PF) and complex II (site IIF) contributed substantially. The effect of Cu depended on substrate and redox site, with effects at sites OF and IIIQo being more pronounced in mitochondria oxidizing pyruvate compared with palmitoylcarnitine. Cu imposed a concentration-saturable effect at site PF but concentration-dependently stimulated H2O2 emission at site EF. The substrate-dependent differences in H2O2 emission and effects of Cu suggest that fuel type and points of entry of electrons into the mitochondrial electron transport system determine the mitochondrial ROS production rate. Importantly, knowledge of sites of mitochondrial ROS production is crucial to the understanding of cardiac dysfunction associated with impaired substrate metabolism
Canine leptospirosis in Canada, test-positive proportion and risk factors (2009 to 2018): A cross-sectional study
No full textOver the past decade, there has been an apparent increased frequency and widened distribution of canine leptospirosis in Canada, however, this has been minimally investigated. Availability and clinical uptake of Leptospira polymerase chain reaction (PCR)-based testing of dogs in Canada may provide important insight into the epidemiology of this canine and zoonotic infectious disease. Study objectives were to evaluate clinical canine Leptospira PCR test results from a large commercial laboratory to determine temporal and spatial distribution in Canada and identify dog, geographic and temporal risk factors for test-positive dogs. This cross-sectional study analyzed data obtained from IDEXX Laboratories, Inc. on 10,437 canine Leptospira PCR tests (blood and/or urine) submitted by Canada-based veterinarians (July 2009 to May 2018). Multivariable logistic regression was used to identify risk factors for test-positive dogs. Test-positive proportion varied widely annually (4.8–14.0%) and by location. Provinces with the highest test-positive proportion over the study period were Nova Scotia (18.5%) and Ontario (9.6%), with the prairie provinces (Manitoba and Alberta combined) having the lowest proportion (1.0%); the northern territories could not be evaluated due to limited testing. In the final model, dog age, sex, breed, month, and year test performed, and location (urban/rural, province) of the practice submitting the sample were significant predictors of a positive Leptospira PCR test. Dogs less than one year of age (OR = 2.1; 95% CI: 1.6–2.9), male sex (OR = 1.3; 1.1–1.5), toy breed (OR = 3.3; 2.5–4.4), and samples submitted from an urban practice (OR = 1.3; 1.0–1.8) had the greatest odds of a positive Leptospira PCR test as compared to referent groups. Significant two-way interactions between province-month and year-month highlight the complex spatial and temporal influences on leptospirosis occurrence in this region. Our work suggests a high incidence of canine leptospirosis regionally within Canada. Identifiable dog and location factors may assist in future targeted prevention efforts
Nietzsche, Trump, and the social practices of valuing truth
No full textWhile Nietzsche offers resources for thinking about the post-truth politics of Donald
Trump, this is not because Nietzsche gives up on truth but because he is prescient in realizing
what is at stake in our esteem for it. Nietzsche argues that the specifically unconditional value we
attribute to truth raises the spectre of nihilism. Trump is a harbinger of this nihilism because he
flaunts our shared social practices of valuing truth. While Nietzsche’s accounts of truth and
objectivity appear to make room for Trump, Nietzsche also praises epistemic virtues—honesty,
courage, curiosity, and responsibility—that Trump surely fails to express