5,137 research outputs found

    Epoxidation of Strained Alkenes Catalysed by (1,2-dimethyl-4(1H)pyridinone-3-olate)2MnIIICl

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    The mild epoxidation of strained alkenes using (DMPO)2MnCl catalyst (DMPO = 1,2-dimethyl-4(1H)-pyridinone-3-olate) in the presence of various oxidants was studied. Hydrogen peroxide and monopersulfate were found to be the best oxidants when used with imidazole in acetonitrile at 4 °C, with up to 94% conversion. Dismutation of hydrogen peroxide was also observed when used as an oxidant. The epoxidation using hydrogen peroxide or monoperoxysulfate appears to be mild and very selective for strained alkenes. A mechanism is proposed where imidazole is required for activation of the oxidant and where a detected MnV = O species is proposed as the active species. Competitive reaction between H2O2 and the substrate for the active species is proposed and homolytic vs heterolytic scissions of the Osingle bondO bond of the oxidant are discussed

    Reference curves for a fitness battery developed for children ages 5-12 years in England

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    Purpose: Reference curves have already been created for a variety of different physical testing batteries across a number of countries. Due to results differing between countries for the same sex and age, it is important that reference curves are created specific for each country. Therefore, the aim of this study was to provide reference curves for five different fitness tests that assess the core components of health related fitness within children in England. Method: Following institutional ethics approval, parental informed consent and child assent was obtained for a total of 39,199 children aged between 5 and 12 years completed tests for explosive power, agility, hand eye coordination, lower body strength and upper body strength. To calculate reference values Generalised Additive Models for Location, Scale and Shape (GAMLSS) were used. Results: Reference curves and centiles show differences in performance levels of the fitness tests between sex and age groups. These reference curves and centiles provide age and sex comparisons to enable progress monitoring of children's physical fitness competence within England and comparisons to other countries. Conclusion: Girls are outperformed from a young age group and both upper and lower body strength decreases are seen at ages nine and ten. In physical activity and health related fitness interventions, both girls and boys in Key stage two should be targeted to maintain progression and lessen the gender divide

    Field Trials with Zinc on Corn

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    Zinc deficiency in corn has been found in isolated instances in Kentucky during the past few years. Usually the deficiency is found in fields having a high pH or in high-phosphate soils with somewhat lower pH values. At present zinc deficiency in Kentucky soils does not appear widespread enough to justify recommending its application except where known deficiencies exist

    Reference curves for a fitness battery developed for children ages 5-12 years in England

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    Purpose: Reference curves have already been created for a variety of different physical testing batteries across a number of countries. Due to results differing between countries for the same sex and age, it is important that reference curves are created specific for each country. Therefore, the aim of this study was to provide reference curves for five different fitness tests that assess the core components of health related fitness within children in England. Method: Following institutional ethics approval, parental informed consent and child assent was obtained for a total of 39,199 children aged between 5 and 12 years completed tests for explosive power, agility, hand eye coordination, lower body strength and upper body strength. To calculate reference values Generalised Additive Models for Location, Scale and Shape (GAMLSS) were used. Results: Reference curves and centiles show differences in performance levels of the fitness tests between sex and age groups. These reference curves and centiles provide age and sex comparisons to enable progress monitoring of children's physical fitness competence within England and comparisons to other countries. Conclusion: Girls are outperformed from a young age group and both upper and lower body strength decreases are seen at ages nine and ten. In physical activity and health related fitness interventions, both girls and boys in Key stage two should be targeted to maintain progression and lessen the gender divide

    Study of the Cause, Measurement, and Reduction of Pressure Surges

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    Exploring Nursing Students\u27 Perceptions of Electronic Fetal Monitoring App

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    Within the healthcare realm, innovative technology has become an integral part of teaching in today’s nursing education, specifically computer-generated teaching applications. A new application that combines both nursing simulation and teaching methods regarding electronic fetal monitoring and fetal heart rhythms was developed at the University of Tennessee in fall 2014.This application was created in collaboration with both the College of Engineering and the College of Nursing. The Electronic Fetal Monitoring App displays instructor-created fetal heart rate (FHR) and maternal contraction patterns to simulate a monitor enabling live- feed interpretation in the classroom or simulation setting. It also has the potential to be saved and recreated for further simulated learning experiences. With current nursing education using processes such as application involvement and simulation in the clinical environment, the evolvement and merger of simulation and technology applications has the potential to exponentially benefit patient outcomes. Therefore, with the creation of a novel simulation application incorporated into the classroom setting, the purpose of this qualitative descriptive study is to explore nursing students’ learning experiences, attitudes, perceptions, and opinions regarding a fluid, dynamic, instructor-manipulated EFM application

    Bone morphogenetic protein-2 (BMP-2) and transforming growth factor-β1 (TGF-β1) alter connexin 43 phosphorylation in MC3T3-E1 Cells

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    BACKGROUND: Bone morphogenetic proteins (BMPs) and transforming growth factor-βs (TGF-βs) are important regulators of bone repair and regeneration. BMP-2 and TGF-β1 have been shown to inhibit gap junctional intercellular communication (GJIC) in MC3T3-E1 cells. Connexin 43 (Cx43) has been shown to mediate GJIC in osteoblasts and it is the predominant gap junctional protein expressed in these murine osteoblast-like cells. We examined the expression, phosphorylation, and subcellular localization of Cx43 after treatment with BMP-2 or TGF-β1 to investigate a possible mechanism for the inhibition of GJIC. RESULTS: Northern blot analysis revealed no detectable change in the expression of Cx43 mRNA. Western blot analysis demonstrated no significant change in the expression of total Cx43 protein. However, significantly higher ratios of unphosphorylated vs. phosphorylated forms of Cx43 were detected after BMP-2 or TGF-β1 treatment. Immunofluorescence and cell protein fractionation revealed no detectable change in the localization of Cx43 between the cytosol and plasma membrane. CONCLUSIONS: BMP-2 and TGF-β1 do not alter expression of Cx43 at the mRNA or protein level. BMP-2 and TGF-β1 may inhibit GJIC by decreasing the phosphorylated form of Cx43 in MC3T3-E1 cells

    The Carnegie Supernova Project: Analysis of the First Sample of Low-Redshift Type-Ia Supernovae

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    We present the analysis of the first set of low-redshift Type Ia supernovae (SNe Ia) by the Carnegie Supernova Project. Well-sampled, high-precision optical (ugriBV) and near-infrared (NIR; YJHKs) light curves obtained in a well-understood photometric system are used to provide light-curve parameters, and ugriBVYJH template light curves. The intrinsic colors at maximum light are calibrated to compute optical--NIR color excesses for the full sample, thus allowing the properties of the reddening law in the host galaxies to be studied. A low value of Rv~1.7, is derived when using the entire sample of SNe. However, when the two highly reddened SNe in the sample are excluded, a value Galactic standard of Rv~3.2 is obtained. The colors of these two events are well matched by a reddening model due to circumstellar dust. The peak luminosities are calibrated using a two-parameter linear fit to the decline rates and the colors, or alternatively, the color excesses. In both cases, dispersions in absolute magnitude of 0.12--0.16 mag are obtained, depending on the filter-color combination. In contrast to the results obtained from color excesses, these fits give Rv~1--2, even when the two highly reddened SNe are excluded. This discrepancy suggests that, beyond the "normal" interstellar reddening produced in the host galaxies, there is an intrinsic dispersion in the colors of SNe Ia which is correlated with luminosity but independent of the decline rate. Finally, a Hubble diagram is produced by combining the results of the fits for each filter. The resulting scatter of 0.12 mag appears to be limited by peculiar velocities as evidenced by the strong correlation between the distance-modulus residuals among the different filters. The implication is that the actual precision of SN Ia distances is 3--4%.Comment: 76 pages, 20 figures, accepted for publication in A

    The Convex Body Isoperimetric Conjecture in the Plane

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    The Convex Body Isoperimetric Conjecture states that the least perimeter needed to enclose a volume within a ball is greater than the least perimeter needed to enclose the same volume within any other convex body of the same volume in Rn. We focus on the conjecture in the plane and prove a new sharp lower bound for the isoperimetric profile of the disk in this case. We prove the conjecture in the case of regular polygons, and show that in a general planar convex body the conjecture holds for small areas
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