Search results for "molecule"
showing 10 items of 5162 documents
A single loading dose of clopidogrel causes dose-dependent improvement of endothelial dysfunction in patients with stable coronary artery disease: Re…
2006
Clinical studies have demonstrated beneficial effects for clopidogrel in patients with atherothrombotic disease. Recent in vitro studies identified stimulating effects of clopidogrel on endothelial cells, pointing towards mechanisms of action beyond the inhibition of platelet aggregation. We hypothesized that in vivo use of clopidogrel improves endothelial dysfunction in patients with coronary artery disease (CAD). Fifty-eight patients with CAD were randomly assigned to double-blinded oral administration of one single dose of clopidogrel 300 mg (C300) or 600 mg (C600), respectively. Endothelial function was assessed by measurement of flow-mediated dilation (FMD) of the brachial artery befor…
Activation of cGMP-dependent Protein Kinase Iβ Inhibits Interleukin 2 Release and Proliferation of T Cell Receptor-stimulated Human Peripheral T Cells
2000
Several major functions of type I cGMP-dependent protein kinase (cGK I) have been established in smooth muscle cells, platelets, endothelial cells, and cardiac myocytes. Here we demonstrate that cGK Ibeta is endogenously expressed in freshly purified human peripheral blood T lymphocytes and inhibits their proliferation and interleukin 2 release. Incubation of human T cells with the NO donor, sodium nitroprusside, or the membrane-permeant cGMP analogs PET-cGMP and 8-pCPT-cGMP, activated cGK I and produced (i) a distinct pattern of phosphorylation of vasodilator-stimulated phosphoprotein, (ii) stimulation of the mitogen-activated protein kinases ERK1/2 and p38 kinase, and, upon anti-CD3 stimu…
Reciprocal regulation of human platelet function by endogenous prostanoids and through multiple prostanoid receptors
2014
Platelets are permanently exposed to a variety of prostanoids formed by blood cells or the vessel wall. The two major prostanoids, prostacyclin and thromboxane act through well established pathways mediated by their respective G-protein coupled receptors inhibiting or promoting platelet aggregation accordingly. Yet the role of other prostanoids and prostanoid receptors for platelet function regulation has not been thoroughly investigated. We aimed at a comprehensive analysis of prostanoid effects on platelets, the receptors and pathways involved and functional consequences. We analyzed cAMP formation and phosphorylation of proteins pivotal to platelet function as well as functional platelet…
A comparison of excited state properties for iterative approximate triples linear response coupled cluster methods
2001
Abstract A computational study of the potential energy curves of the 1 Π state of BH, 1 Π state of CH + , 1 Σ u and 1 Π u states of C 2 , 1 Π state of CO, and 1 Π g and 1 Σ − u states of N 2 is carried out with the CC3 and CCSDT-3 corrections to EOMEE-CCSD. Good agreement in structure, vibrational frequencies, and excitation energies of these iterative triples-corrected methods with respect to experiment is found for most of these examples. However, deficiencies in the approximate treatment of triples is evident for BH and CH + .
Equation-of-motion coupled-cluster methods for ionized states with an approximate treatment of triple excitations.
2005
The accuracy of geometries and harmonic vibrational frequencies is evaluated for two equation-of-motion ionization potential coupled-cluster methods including CC3 and CCSDT-3 triples corrections. The first two Sigma states and first Pi state of the N2 +, CO+, CN, and BO diatomic radicals are studied. The calculations show a tendency for the CC3 variant to overestimate the bond lengths and to underestimate the vibrational frequencies, while the CCSDT-3 variant seems to be more reliable. It is also demonstrated that the accuracy of such methods is comparable to sophisticated traditional multireference approaches and the full configuration interaction method.
Structure of Dioxygen Binding Xerogels Incorporating Cyclams Complexed with CuCl2 Salts
2005
X-ray absorption/emission spectroscopies were combined in order to elucidate how hybrid xerogels complexed with CuCl2 could bind reversibly O2. Difference EXAFS analyses at the Cu K-edge revealed the existence of binuclear structures with long Cu...Cu distances, i.e. RCu–Cu ≈ 3.98 A and 3.87 A for the oxygenated and oxygen-free xerogels. In oxygenated xerogels, dioxygen would bridge two Cu atoms in a μ-η1 : η1 peroxo-like conformation. The Cu-O signal found at short distance (RCu−O1 = 1.85 ± 0.01 A) is fully consistent with 40% of O2 molecules being chemisorbed per Cu site. In oxygen-free xerogels, Cl K-edge EXAFS revealed the presence of CuI sites with short Cl-Cu bond lengths (RCl−Cu = 2.…
Bis(dimethylammonium) pentachloroantimonate(III), on the deformation of the octahedral coordination of Sb III
1998
The structure of the title compound, [NH2(CH3)2]2SbCl5, was determined at 295 and 85 K. It consists of polymeric (SbCl52−)n chains composed of deformed SbCl63− octahedra connected by corners and dimethylammonium cations. The temperature dependence of the Sb–Cl bond lengths is discussed. It is argued that the deformation of the octahedral coordination of the SbIII atom is caused by electrostatic interaction/hydrogen bonds.
On the geometry of the HO3 radical
2008
Abstract We discuss the equilibrium structure of the hydrogen trioxy radical (HO3). The CCSD(T) geometry at the approximate basis set limit, in conjunction with the geometry obtained using the CCSDT method and a moderate basis set, suggests an equilibrium HO–OO bond length of approximately 1.59 A.
Continuum Monte Carlo simulation of phase transitions in rod-like molecules at surfaces
1994
Stiff rod-like chain molecules with harmonic bond length potentials and trigonometric bond angle potentials are used to model Langmuir monolayers at high densities. One end of the rod-like molecules is strongly bound to a flat two-dimensional substrate which represents the air-water interface. A ground-state analysis is performed which suggests phase transitions between phases with and without collective uniform tilt. Large-scale off-lattice Monte Carlo simulations over a wide temperature range show in addition to the tilting transition the presence of a strongly constrained melting transition at high temperatures. The latter transition appears to be related to two-dimensional melting of th…
AM1 prediction of the equilibrium geometry of Si60
1993
Abstract AM1 calculations have been carried out to determine the equilibrium geometry of Si 60 . The predicted I h geometry shows that bonds may be clearly identified as single (2.297 A) or aromatic (2.092 A). Several analogies and differences between Si 60 and C 60 are pointed out. Especially remarkable is the bigger size of the Si 60 cluster, which is predicted to have a radius 2 A larger than that of the C 60 cluster. Results are compared to other levels of theory.