102 research outputs found
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 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
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
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
Yb3+:(LuxY1−x)2O3 mixed sesquioxide ceramics for laser applications. Part I: Fabrication, microstructure and spectroscopy
We report an in-depth investigation (fabrication, microstructure and spectroscopy) of Yb3+-doped mixed sesquioxide transparent ceramics (LuxY1−x)2O3 with x = 0, 0.113 and 0.232. The ceramics were fabricated by vacuum sintering of nano-sized particles synthesized by CO2 laser co-evaporation of the corresponding solid targets with different Y/Lu balance. The effect of Lu3+ concentration on crystal structure and phase evolution of the nanopowders and microstructure, optical and spectroscopic properties of the sintered ceramics was investigated. The micro-Raman measurements with high spatial resolution revealed a homogeneous distribution of both yttrium and lutetium in the mixed composition. The optical transmission of 1.4 mm-thick ceramics was over 80% in the wavelength range of 500–1100 nm. Partial substitution of Y3+ cations for Lu3+ cations determines a small shift toward longer wavelengths and broadening of the Yb3+ main emission peaks at about 1030 and 1076 nm. This is the first extensive characterization of the spectroscopic properties of Yb:(Y,Lu)2O3 compositional family in ceramic hosts. © 2021 Elsevier B.V.Russian Foundation for Basic Research, РФФИ, (18-53-7815 Ital_t, SAC.AD002.020.016)Consiglio Nazionale delle Ricerche, CNRThis work was supported in part by the Joint Bilateral Agreement National Research Council (CNR), Italy/ Russian Foundation for Basic Research (RFBR), Russia, 2018–2020 (RFBR Grant No. 18-53-7815 Ital_t , CNR project SAC.AD002.020.016 )
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
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