quaternary ammonium compounds (qacs) are employed both as disinfectants for manual processing lines and surfaces in the food industry, and in human medicine area. qacs also cause cell death by protein denaturation . one of the qac is cetyl trimethyl ammonium bromide (ctab) that appears to rapture the cell membrane. the primary site of action of ctab has been suggested to be the lipid components...

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...

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...

Influence of Aluminum, Gallium, Indium- Doping on the Boron-Nitride Nanotubes (BNNTs) investigated with density functional theory (DFT) and Hartreefock (HF) methods. For this purpose, the chemical shift of difference atomic nucleus was studied using the gauge included atomic orbital (GIAO) approch. In the following, structural parameter values, electrostatic potential, thermodynamic parameters,...

some of the adamantane properties were calculated in this study. chemical shift, free energy ofsolvation, free energy of cavity formation, henry's law constant, and other properties ofadamantane in dry phase, three solvents and three temperatures have been calculated with abinitio method base on density functional theory (dft) at b3lyp/6-31g, b31yp/6-31g*, b3lyp/6-31+g* and b3lyp/6-31++g** leve...

in the present work, the quantum theoretical calculations of the molecular structure of the 1-(1, 3-benzothiazol-2-yl)-3-(thiophene-5-carbonyl) thiourea has been predicted and are evaluated using density functional theory (dft) in gas phase. the geometry of the title compound was optimized by b3lyp/6-311+g and b3lyp/6-311+g* methods and the experimental geometrical parameters of the title compo...

influence of aluminum, gallium, indium- doping on the boron-nitride nanotubes (bnnts) investigated with density functional theory (dft) and hartreefock (hf) methods. for this purpose, the chemical shift of difference atomic nucleus was studied using the gauge included atomic orbital (giao) approch. in the following, structural parameter values, electrostatic potential, thermodynamic parameters,...

A new NMR experiment which allows a measurement of the chemical shift anisotropy (CSA) tensor under magic angle spinning (MAS) is described. This correlates a fast MAS spectrum in the omega2 dimension with a sideband pattern in omega1 in which the intensities mimic those for a sample spinning at a fraction of the rate omega r/N, and these sidebands result from an amplification by a factor N of ...

We have obtained the 13CR chemical shift tensors for each amino acid in the protein GB1. We then developed a CST force field and incorporated this into the Xplor-NIH structure determination program. GB1 structures obtained by using CST restraints had improved precision over those obtained in the absence of CST restraints and were also more accurate. When combined with isotropic chemical shifts,...

A novel method of chemical shift imaging utilizing echoplanar imaging (EPI) has been developed for the purpose of improving the spatial resolution of metabolite images for the specific goal of high spatial resolution mapping of neuronal content. An EPI sequence was modified to allow temporal offsets of the 180 degree refocusing pulse that encode the chemical shift information into the phase of ...