75 research outputs found
Validation of an echo-Doppler decision model to predict left ventricular filling pressure in patients with heart failure independently of ejection fraction
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Modelling charge self-trapping in wide-gap dielectrics: Localization problem in local density functionals
We discuss the adiabatic self-trapping of small polarons within the density
functional theory (DFT). In particular, we carried out plane-wave
pseudo-potential calculations of the triplet exciton in NaCl and found no
energy minimum corresponding to the self-trapped exciton (STE) contrary to the
experimental evidence and previous calculations. To explore the origin of this
problem we modelled the self-trapped hole in NaCl using hybrid density
functionals and an embedded cluster method. Calculations show that the
stability of the self-trapped state of the hole drastically depends on the
amount of the exact exchange in the density functional: at less than 30% of the
Hartree-Fock exchange, only delocalized hole is stable, at 50% - both
delocalized and self-trapped states are stable, while further increase of exact
exchange results in only the self-trapped state being stable. We argue that the
main contributions to the self-trapping energy such as the kinetic energy of
the localizing charge, the chemical bond formation of the di-halogen quasi
molecule, and the lattice polarization, are represented incorrectly within the
Kohn-Sham (KS) based approaches.Comment: 6 figures, 1 tabl
Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial
IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved
Blends of Poly(ethylene 2,6-naphthalate) With Liquid Crystalline Polymers: Crystallization Behavior and Morphology
Banded Texture in Sheared Semiflexible Thermotropic Liquid Crystalline Polyester and Its Graft Copolymers With Polyolefins
Organoclay Nanocomposites from Ethylene-Acrylic Acid Copolymers
A study of the structure\u2013property relationships for nanocomposites prepared by melt compounding from ethylene\u2013acrylic acid copolymers of varied composition and molecular architecture, and organoclays modified with different ammonium ions has been made by DSC, POM, SEM, TEM, WAXD, and rheological and mechanical tests. Within the series of clays investigated, the best levels of dispersion were displayed by those organically modified with quaternary ammonium ions containing two long alkyl tails. The relevant nanocomposites were shown to possess mixed exfoliated and intercalated morphology. The spacing of the intercalated clay stacks, most of which comprise few silicate layers, was found to be independent of clay loading, in the range of 2\u201350 phr, and to change with the molecular architecture of the matrix polymer. An indication that the excess
surfactant present in some of the clays, and the organic material added in others to expand the interlayer spacing, were expelled from the clay galleries during melt blending and acted as plasticisers for the matrix polymer, was obtained from WAXD and rheological characterisations
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