207 research outputs found

    Experimental and Theoretical Studies of the Redox Potentials of Cyclic Nitroxides

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    (Chemical Equation Presented) The redox potentials of 25 cyclic nitroxides from four different structural classes (pyrrolidine, piperidine, isoindoline, and azaphenalene) were determined experimentally by cyclic voltammetry in acetonitrile, and also via high-level ab initio molecular orbital calculations. It is shown that the potentials are influenced by the type of ring system, ring substituents and/or groups surrounding the radical moiety. For the pyrrolidine, piperidine, and isoindolines there is excellent agreement (mean absolute deviation of 0.05 V) between the calculated and experimental oxidation potentials; for the azaphenalenes, however, there is an extraordinary discrepancy (mean absolute deviation of 0.60 V), implying that their one-electron oxidation might involve additional processes not considered in the theoretical calculations. This recently developed azaphenalene class of nitroxide represents a new variant of a nitroxide ring fused to an aromatic system and details of the synthesis of five derivatives involving differing aryl substitution are also presented

    What you know can influence what you are going to know (especially for older adults)

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    Stimuli related to an individual's knowledge/experience are often more memorable than abstract stimuli, particularly for older adults. This has been found when material that is congruent with knowledge is contrasted with material that is incongruent with knowledge, but there is little research on a possible graded effect of congruency. The present study manipulated the degree of congruency of study material with participants’ knowledge. Young and older participants associated two famous names to nonfamous faces, where the similarity between the nonfamous faces and the real famous individuals varied. These associations were incrementally easier to remember as the name-face combinations became more congruent with prior knowledge, demonstrating a graded congruency effect, as opposed to an effect based simply on the presence or absence of associations to prior knowledge. Older adults tended to show greater susceptibility to the effect than young adults, with a significant age difference for extreme stimuli, in line with previous literature showing that schematic support in memory tasks particularly benefits older adults

    Explorations, Vol. 5, No. 1

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    Articles include: Cover: What Have We Done with Tomorrow? by Leslie C. Hyde, UMCES Extension Agent for Knox-Lincoln Counties. Editorial Reflections, Carole J. Bombard UMCES: an overview Conversation with the Director: Assistant Vice-President Judith Bailey Reaching Out for Teen Awareness, by Theresa M. Ferrari Profile of a Harbormaster, by Carole J. Bombard Minding Maine’s Business, by Mary S. Bowie Family Resource Management: Learning to ease the burden, by Olive Dubord and Doris Cushman Breaking Free and Taking Control: Helen Sawyer’s Story, by Doris Manley Partnership in Conservation: The Josephine Newman Sanctuary, by Nancy Coverstone The Mount Desert Island Health Promotion Project, by Ron Beard Dynamics of Weed Control in Agriculture, by Leigh Morrow From Generation to Generation: An Extension Homemaker Family, by Nadine B. Reimer ICLAD: The Institute for Community Leadership and Development, by Jim Killacky and Deb Burwell Exploding the Cinderella Syndrome: Strengthening Stepfamilies, by Wendy Pollock Integrated Pest Management: Bringing it all together, by Glen Koehler and Jim Dill Addressing the Issues, by Patricia M. Pierson Anti-Bruise: What’s It All About? Maine Potato Harvest Anti-Bruise Program, by Neal D. Hallee H.O.P.E. Addresses Teenage Pregnancy, by Jane M. Kelly Saving Money and the Environment, by Vaughn H. Holyoke Reservoir Tillage in Nonirrigated Potato Production, by Leigh Morrow Managing Pesticide Drift, by James D. Dwyer, Leigh S. Morrow and James F. Dill The St. George River Project — what have we done with tomorrow? Putting Research to Work, by Stephen Belyea The Best Maine Blue: Fresh Pack Blueberries, by Tom DeGomez Maine’s Green Sea Urchin, by Benjamin A. Baxter Interfaces and Cooperation: Wildlife and Fisheries Sampler, by Catherine A. Elliott Extension Responds to the Salmonella Scare, by Nellie Hedstrom and Mahmoud El-Begearm

    Two-Photon Fluorescence Microscopy Imaging of Cellular Oxidative Stress Using Profluorescent Nitroxides

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    A range of varying chromophore nitroxide free radicals and their nonradical methoxyamine analogues were synthesized and their linear photophysical properties examined. The presence of the proximate free radical masks the chromophore’s usual fluorescence emission, and these species are described as profluorescent. Two nitroxides incorporating anthracene and fluorescein chromophores (compounds 7 and 19, respectively) exhibited two-photon absorption (2PA) cross sections of approximately 400 G.M. when excited at wavelengths greater than 800 nm. Both of these profluorescent nitroxides demonstrated low cytotoxicity toward Chinese hamster ovary (CHO) cells. Imaging colocalization experiments with the commercially available CellROX Deep Red oxidative stress monitor demonstrated good cellular uptake of the nitroxide probes. Sensitivity of the nitroxide probes to H2O2-induced damage was also demonstrated by both one- and two-photon fluorescence microscopy. These profluorescent nitroxide probes are potentially powerful tools for imaging oxidative stress in biological systems, and they essentially “light up” in the presence of certain species generated from oxidative stress. The high ratio of the fluorescence quantum yield between the profluorescent nitroxide species and their nonradical adducts provides the sensitivity required for measuring a range of cellular redox environments. Furthermore, their reasonable 2PA cross sections provide for the option of using two-photon fluorescence microscopy, which circumvents commonly encountered disadvantages associated with one-photon imaging such as photobleaching and poor tissue penetration

    Viral escape mutations do not account for non-protection from SIVmac239 challenge in RhCMV/SIV vaccinated rhesus macaques

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    Simian immunodeficiency virus (SIV) vaccines based upon 68-1 Rhesus Cytomegalovirus (RhCMV) vectors show remarkable protection against pathogenic SIVmac239 challenge. Across multiple independent rhesus macaque (RM) challenge studies, nearly 60% of vaccinated RM show early, complete arrest of SIVmac239 replication after effective challenge, whereas the remainder show progressive infection similar to controls. Here, we performed viral sequencing to determine whether the failure to control viral replication in non-protected RMs is associated with the acquisition of viral escape mutations. While low level viral mutations accumulated in all animals by 28 days-post-challenge, which is after the establishment of viral control in protected animals, the dominant circulating virus in virtually all unprotected RMs was nearly identical to the challenge stock, and there was no difference in mutation patterns between this cohort and unvaccinated controls. These data definitively demonstrate that viral mutation does not explain lack of viral control in RMs not protected by RhCMV/SIV vaccination. We further demonstrate that during chronic infection RhCMV/SIV vaccinated RMs do not acquire escape mutation in epitopes targeted by RhCMV/SIV, but instead display mutation in canonical MHC-Ia epitopes similar to unvaccinated RMs. This suggests that after the initial failure of viral control, unconventional T cell responses induced by 68-1 RhCMV/SIV vaccination do not exert strong selective pressure on systemically replicating SIV

    Natriuretic peptides, body mass index and heart failure risk: Pooled analyses of SAVOR-TIMI 53, DECLARE-TIMI 58 and CAMELLIA-TIMI 61.

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    AimN-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations are lower in patients with obesity. The interaction between body mass index (BMI) and NT-proBNP with respect to heart failure risk remains incompletely defined.Methods and resultsData were pooled across three randomized clinical trials enrolling predominantly patients who were overweight or obese with established cardiometabolic disease: SAVOR-TIMI 53, DECLARE-TIMI 58 and CAMELLIA-TIMI 61. Hospitalization for heart failure (HHF) was examined across strata of baseline BMI and NT-proBNP. The effect of dapagliflozin versus placebo was assessed for a treatment interaction across BMI categories in patients with or without an elevated baseline NT-proBNP (≥125 pg/ml). Among 24 455 patients, the median NT-proBNP was 96 (interquartile range [IQR]: 43-225) pg/ml and the median BMI was 33 (IQR 29-37) kg/m2 , with 68% of patients having a BMI ≥30 kg/m2 . There was a significant inverse association between NT-proBNP and BMI which persisted after adjustment for all clinical variables (p 2 for NT-proBNP ranges of adj ] 7.47, 95% confidence interval [CI] 3.16-17.66, HRadj 3.22 [95% CI 2.13-4.86], and HRadj 1.87 [95% CI 1.35-2.60], respectively). In DECLARE-TIMI 58, dapagliflozin versus placebo consistently reduced HHF across BMI categories in those with an elevated NT-proBNP (p-trend for HR across BMI = 0.60), with a pattern of greater absolute risk reduction (ARR) at higher BMI (ARR for BMI 2 : 2.2% to 4.7%; p-trend = 0.059).ConclusionsThe risk of HHF varies across BMI categories for any given range of circulating NT-proBNP. These findings showcase the importance of considering BMI when applying NT-proBNP for heart failure risk stratification, particularly for patients with low-level elevations in NT-proBNP (125-<450 pg/ml) where there appears to be a clinically meaningful absolute and relative risk gradient

    Moving beyond fan typologies: The impact of social integration on team loyalty in football

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    The purpose of this paper is to develop detailed insight into loyalty among football fans of Hibernian FC, moving beyond typologies to a more socially grounded approach. Issues explored include patterns of consumption, distinctions between fan groups, and antecedents of loyalty. The origins and development of the club are evaluated, and consumer fanaticism, football fan loyalty, consumption behaviour, and the sociological impact of fan communities are discussed. Data were collected using a variety of methods, including participant observation, in-depth interviews, and analysis of websites and fan forums. Key findings relate to the impact of family and community influences on loyalty, initial experiences of developing associations with the club, through to the impact of socialisation, and the lived experience of being a supporter. A supporter matrix is constructed as a portrayal of the loyalty found at the club. A range of theoretical implications is considered, and the matrix promoted as a tool for understanding loyalty in clubs with similar social structures and community connections
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