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...

using the density functional theory (dft) level by means of 3-21g, 6-31g and 6-31+g (d) basissets, the structural optimization of isolated pyrazole and pyrazoline was done in the gas phase. then,the calculation about the solvent effect on the stability energies of pyrazole and pyrazoline wasperformed for the ten solvents using pcm model method at b3lyp/6-31+g(d) and then the dielectriceffects o...

In antimalarial research there are no standard procedures to determine the toxicity of a drug candidate. Among alternatives available, in vitro cytotoxicity assays most widely used predict toxic effects future therapeutic products. They have advantage over vivo assays, that they offer possibility restrain number experimental variables. The objective present study was compare cytotoxic methods b...

One hundred (lOO) consecutive patients who underwent spinal analgesia for surgical and orthopaedic operations were studied. Postural headache occurred in 9% of patients, the majority in those cases where large bore (l8G to 21G) needless were used. No other neurological complications were encountered. Conservative measures provided some relief of the headache. Epidural blood patch was found to b...

We investigated inflammatory and physiologic parameters in sepsis models of increasing lethality induced by cecal ligation and puncture (CLP). Mice received imipenem for antibiotic therapy, and groups were sacrificed at 2, 4, 8, 12, 16, 20, and 24 h after CLP. The severity of sepsis increased with needle puncture size (lethality with 18-gauge puncture [18G], 100%; 21G, 50%; 25G, 5%; sham treatm...

The combination of Quantum Mechanics (QM) and Molecular Mechanics (MM) methods hasbecome alternative tool for many applications that pure QM and MM could not be suitable.The QM/MM method has been used for different type of problems, for example: structuralbiology, surface phenomena, and liquid phase. In this paper we have performed these methods forsome antibiotics and vitamins and then we comp...

over the past decade, the chemical behavior of flavonoids as antioxidants has become the subject ofintense experimental research. in this paper, we use a quantum-chemical approach to shed light on thereactivity of four poly phenols, benzoic acid, vanilic acid, gallic acid and flavone . in order to establishthe most efficient theoretical methodology, different methods, either hartree—fock-based ...

The structures of ideal armchair (5,5) single-wall carbon nanotubes (SWCNTs) of different lengths (3.7, 8.8, and 16.0 Å for C(40)H(20), C(80)H(20), and C(140)H(20)) and with 1-10 hydroxyl groups at the end of the nanotube were fully optimized at the B3LYP/3-21G level, and in some cases at the B3LYP/6-31G level, and the energy associated with the attachment of the OH substituent was determined. ...

phospholipids are important for the biological lipid and are commonly used in biophysical studies.A quantumcalculation for two phospholipids Dipalmitoylphosphatidylethanolamine and dipalmitoylphosphatidic acidwere performed using the abinitio software. Geometry optimization structures were obtained at RHF level using3-21G, 6-31G*. These basis sets were used To understanding the effects of envir...

In the present work a quantum chemical study of a series of substituted hydrofullerenes, C(60)HR, and a series of methanofullerenes, C(60)(CHR), is presented. Their reactivity and geometrical, energetic, electronic, and magnetic properties, as well as the influence of the substituent, are discussed. As a probe of the reactivity, the acidic properties of these fullerene derivatives were predicte...