the acidity constants (pka) of thirty four (34) ;-substituted carboxylic acids in aqueous solution havebeen calculated using conductor-like polarizable continuum (c-pcm) solvation model. the gasphaseenergies at the density functional theory (dft-mpw1pw91) and solvation energies athartree fock (hf) are combined to estimate the pka values which are very close to the experimentalvalues where, and ...

nowadays nmr spectroscopy becomes a powerful tool in chemistry because of the nmr chemical shifts. hartree–fock theory and the gauge-including atomic orbital (giao) methods are used in the calculation of 29si nmr chemical shifts of various silicate species in the silicate solution as initial components for zeolite synthesis both in gas and solution phase. calculations have been performed at geo...

the acidity constants (pka) of thirty four (34) ;-substituted carboxylic acids in aqueous solution havebeen calculated using conductor-like polarizable continuum (c-pcm) solvation model. the gasphaseenergies at the density functional theory (dft-mpw1pw91) and solvation energies athartree fock (hf) are combined to estimate the pka values which are very close to the experimentalvalues where, and ...

vinblastine is an important anticancer agent known to diminish microtubule assembly. ab initio calculations are applied to examine the structural properties and different energies of vinblastine-tubulin complex in different dielectric constants and temperatures. the aims of this work are discovery the best optimized structure and thermodynamic properties of vinblastine-tubulin complex and compa...

enaminones are those structures made up three various functional groups including carbonyl, alkeneand amine groups which arelocated along with each other in a conjugate fashion. these compoundsare of much attention due to special characteristics and numerous applications. in the paper, sixvarious enaminone structures were theoretically optimized and after concluding, were compared withequivalen...

vitamin d deficiency is common among the elderly with and without heart failure (hf). this study was designed to identify the degree of vitamin d deficiency among hf and non- hf elderly with cardiovascular disease. in this study, fifty hospitalized elderly patients with hf (26 women and 24 men, age range 60-90 years) and fifty elderly without hf were randomly selected. the level of serum 25-hyd...

We consider a (semi-)relativistic spin-1/2 particle interacting with quantized radiation. The Hamiltonian has the form Ĥ c := {c2[(p + A) +σ ·B] + (mc2)2}1/2 −mc2 +V +Hf . Assuming that the potential |V | is bounded with respect to the momentum |p|, we show that Ĥ c converges in norm-resolvent sense to the usual Pauli-Fierz operator when c, the speed of light, tends to ∞.