the structural and energetic characteristics of o3–h2o complexes have been investigated by means of b3lyp, mp2, mp4(sdtq), ccsd(t) and qcisd(t) methods in conjunction with the aug-cc-pvdz and aug-cc-pvtz basis sets. six conformers were found for the o3–h2o complex. two different intermolecular interactions were expected to participate in the formation of complexes, namely conventional o∙∙∙h hyd...

an ab initio and density functional theory (dft) study about conformational analysis of tripeptide model hco−gly−l−ile−gly−nh2 is presented. the tripeptide was scanned about initial, central, and final residues, separately while for every scanning procedure the two other residues had been kept in the β conformation and side chain (sc) dihedral angles were maintained on the gauche− (g‾) state (χ...

ab initio calculations at hf/6-31g* level of theory for geometry optimization and mp2/6-31g*//hf/6-31g*for total energy calculation are reported for z-cyclooctene (1). the most favorable conformation of 1 is theunsymmetric boat-chair (1-bc) geometry. potential energy profiles for two different boat-chair/boat-chairinterconversion processes were calculated. the process via a chair transition sta...

the thermodynamic functions such as enthalpy (h), gibbs free energy (g) and entropy (s) of serineand threonine amino acids were theoretically studied at different condition (solvents andtemperatures) by using gussian o3, software. first, the structural optimization of isolated serine andthreonine were done in the gas phase by using the hartree-fock (hf) level of theory with 3-21g, 6-31g and 6-3...

A challenge in free energy calculation for complex molecular systems by computer simulation is to obtain a reliable estimate within feasible computational time. In this study, we suggest an answer to this challenge by exploring a simple method, overlap sampling (OS), for producing reliable free-energy results in an efficient way. The formalism of the OS method is based on ensuring sampling of i...

UNLABELLED In the daily practice of in-hospital or centralized radiopharmacies, there is a need to perform reliable numeric calculations. Furthermore, several nuclear medicine diagnostic tests also involve carrying out calculations. In both cases, these calculations are sometimes complex or tedious and prone to error. We report the development of a computer software program that performs a comp...

In this project, new derivatives of fluorescein were synthesized using the reaction of maleic anhydride and saccharin with phenol derivatives in the presence of ZnCl2, and their structures were elucidated by UV, IR, and NMR spectroscopy. Fluorimetry studies showed that, the synthesized compounds can be utilized as fluorescent agents, and their efficiencies were dependent on pH of solution. Acco...

Seismic-protection measures make it possible to significantly decrease economical losses. Seismic shock absorption systems and seismic insulation of foundations and buildings can generally increase the reliability of structures. Calculations by Ja. M. Ajzenberg showed that relative horizontal seismic shifts of floors in seismically insulated buildings are significantly lower than in noninsulate...

The problems of artificial neural networks learning and their parallelisation are taken up in this article. The article shows comparison of the Levenberg-Marquardt’s method (LMM) and its two modifications JWM (method with Jacobian matrices formed in each step) and BKM (Jacobian calculations only in the first step) for training artificial neural networks. These algorithms have the following prop...