On the absolute age of the Globular Cluster M92

We present precise and deep optical photometry of the globular M92. Data were collected in three different photometric systems: Sloan Digital Sky Survey (g',r',i',z'; MegaCam@CFHT), Johnson-Kron-Cousins (B, V, I; various ground-based telescopes) and Advanced Camera for Surveys (ACS) Vegamag (F475W, F555W, F814W; Hubble Space Telescope). Special attention was given to the photometric calibration, and the precision of the ground-based data is generally better than 0.01 mag. We computed a new set of {\alpha}-enhanced evolutionary models accounting for the gravitational settling of heavy elements at fixed chemical composition ([{\alpha}/Fe]=+0.3, [Fe/H]=-2.32 dex, Y=0.248). The isochrones -- assuming the same true distance modulus ({\mu}=14.74 mag), the same reddening (E(B-V)=0.025+-0.010 mag), and the same reddening law -- account for the stellar distribution along the main sequence and the red giant branch in different Color-Magnitude Diagrams (i',g'-i' ; i',g'-r' ; i',g'-z' ; I,B-I ; F814W,F475W-F814W). The same outcome applies to the comparison between the predicted Zero-Age-Horizontal-Branch (ZAHB) and the HB stars. We also found a cluster age of 11 +/- 1.5 Gyr, in good agreement with previous estimates. The error budget accounts for uncertainties in the input physics and the photometry. To test the possible occurrence of CNO-enhanced stars, we also computed two sets of {\alpha}- and CNO-enhanced (by a factor of three) models both at fixed total metallicity ([M/H]=-2.10 dex) and at fixed iron abundance. We found that the isochrones based on the former set give the same cluster age (11 +/- 1.5 Gyr) as the canonical {\alpha}-enhanced isochrones. The isochrones based on the latter set also give a similar cluster age (10 +/- 1.5 Gyr). These indings support previous results concerning the weak sensitivity of cluster isochrones to CNO-enhanced chemical mixtures.Comment: This paper makes use of data obtained from the Isaac Newton Group Archive which is maintained as part of the CASU Astronomical Data Centre at the Institute of Astronomy, Cambridge. This research used the facilities of the Canadian Astronomy Data Centre operated by the National Research Council of Canada with the support of the Canadian Space Agenc

Does ergometric stress test induce a procoagulative condition in patients with previous myocardial infarction

A regularly scheduled physical training program seems to have antithrombotic effects. Moreover, the hemostatic changes occurring in patients with coronary artery disease during acute exercise have not been clearly elucidated. Since stress testing is routinely performed in clinical cardiology, it would be helpful to assess whether patients with coronary artery disease are exposed to acute coronary thrombosis during or soon after sustained physical exercise. This study was designed to evaluate the effect of acute physical exercise (stress test by bicycle ergometer) on blood coagulation in a group of patients with previous myocardial infarction, and to determine whether the antithrombotic therapy commonly administered favorably influences hemostatic equilibrium. Our results suggest that exercise testing is not harmful to patients with previous myocardial infarction in regard to hemostasis and fibrinolysis and that antithrombotic therapy reduces postexercise increase in platelets

On the Delta V_HB_bump parameter in Globular Clusters

We present new empirical estimates of the Delta V_HB_bump parameter for 15 Galactic globular clusters (GGCs) using accurate and homogeneous ground-based optical data. Together with similar evaluations available in the literature, we ended up with a sample of 62 GGCs covering a very broad range in metal content (-2.16<=[M/H]<=-0.58 dex). Adopting the homogeneous metallicity scale provided either by Kraft & Ivans (2004) or by Carretta et al. (2009), we found that the observed Delta V_HB_bump parameters are larger than predicted. In the metal-poor regime ([M/H]<=-1.7, -1.6 dex) 40% of GCs show discrepancies of 2sigma (~0.40 mag) or more. Evolutionary models that account either for alpha- and CNO-enhancement or for helium enhancement do not alleviate the discrepancy between theory and observations. The outcome is the same if we use the new Solar heavy-element mixture. The comparison between alpha- and CNO-enhanced evolutionary models and observations in the Carretta et al. metallicity scale also indicates that observed Delta V_HB_bump parameters, in the metal-rich regime ([M/H]=>0), might be systematically smaller than predicted

Regulation of the Cardiac Na+/K+ ATPase by Phospholemman

Hansraj Dhayan, Rajender Kumar, Andreas Kukol, ‘Regulation of the Cardiac Na+/K+ ATPase by Phospholemman’, in Sajal Chakraborti, Naranjan Dhalla, eds., Regulation of Membrane Na+-K+ ATPase, (Switzerland: Springer, 2016), ISBN 978-3-319-24748-9, eISBN 978-3-319-24750-2.Peer reviewe

Substituents modulate biphenyl penetration into lipid membranes

Electrochemical impedance techniques and fluorescence spectroscopic methods have been applied to the study of the interaction of ortho (o)-, meta (m)- and para (p)-Cl-, o-, m- and p-HO-, p-H3CO-, p-H3C-, p-NC- and p-O3− S- substituted biphenyls (BPs) with Hg supported dioleoyl phosphatidylcholine (DOPC) monolayers and DOPC vesicles. Non-planar o-substituted BPs exhibit the weakest interactions whereas planar p-substituted BPs interact to the greatest extent with the DOPC layers. The substituted BP/DOPC monolayer and bilayer interaction depends on the effect of the substituent on the aromatic electron density, which is related to the substituents’ mesomeric Hammetts constants. Substituted BPs with increased ring electron density do not increase the DOPC monolayer thickness on Hg and penetrate the DOPC vesicle membranes to the greatest extent. Substituted BPs with lower ring electron density can cause an increase in the monolayer’s thickness on Hg depending on their location and they remain in the interfacial and superficial layer of the free standing DOPC membranes. Quantum mechanical calculations correlate the binding energy between the substituted BP rings and methyl acetate, as a model for the –CH2-(CO)O-CH2- fragment of a DOPC molecule, with the location of BPs within the DOPC monolayer