A hybrid quantum mechanical and molecular mechanical potential is used in Monte Carlo simulations to examine the solvent effects on the electronic excitation energy of the n → π(*) transition of acetone in ambient and supercritical water fluid, in which the temperature is in the range of 25-500 °C with pressures of 1-2763 atm. In the present study, the acetone molecule is described by the AM1 H...

The solvent displacement method involves three main steps to obtain nanoparticles: dissolution of both the polymer and the drug into a solvent, mixing of the obtained solution with the anti-solvent, and elimination of the solvent through evaporation. 1 Mixing leads to rapid diffusion of the solvent into the anti-solvent and spontaneous particle formation. Particle formation is extremely rapid a...

air conditioning refrigerant r134a has value of global warming potential (gwp) 1300, which is much higher than mac directive (gwp below 150) passed in july 2006. this prompted a search for alternative refrigerant with gwp value less than 150. r1234yf is a new refrigerant which has lower gwp value of 4. effect of blower speed has been compared and flammability issue of r1234yf has been addressed...

using the gaussian 2003 software and mp2 /6 – 311+ g method for the c2h4 : o2, co:cl2 andco2:co2 pairs and mp2/6-311++g** method for the co2:h2o pair and b3lyp/6-31g methodfor the o2:o2 pair the optimized interaction energies between two considered pair molecules ofstudied gases(c2h4:o2, co:cl2, co2:h2o, o2:o2 and co2:co2 pairs) as a function of thedistances between the centers of two considere...

A global optimization method is described for identifying the global minimum energy conformation, as well as lower and upper bounds on the global minimum conformer of solvated peptides. Potential energy contributions are calculated using the ECEPP/3 force eld model. In considering the eeects of hydration, two implicit free energy models are compared. One method is based on the calculation of so...

Evaluating solvation entropies directly and combining with direct energy calculations is one way of calculating free energies of solvation and is used by Inhomogeneous Fluid Solvation Theory (IFST). The configurational entropy of a fluid is a function of the interatomic correlations and can thus be expressed in terms of correlation functions. The entropies in this work are directly calculated f...

The Generalized Born (GB) continuum solvent model is arguably the most widely used implicit solvent model in protein folding and protein structure prediction simulations; however, it still remains an open question on how well the model behaves in these large-scale simulations. The current study uses the beta-hairpin from C-terminus of protein G as an example to explore the folding free energy l...

The potential energy surface of an off-lattice model protein is characterized in detail by constructing a disconnectivity graph and by examining the organisation of pathways on the surface. The results clearly reveal the frustration exhibited by this system and explain why it does not fold efficiently to the global potential energy minimum. In contrast, when the frustration is removed by constr...

the kinetics and mechanism of the reaction of 5-nitro-1h-benzo[d] imidazole to produce 6-nitro-1h-benzo[d] imidazole was studied by employing hybrid meta-density functional theory. mpwblk/6-31+g** level calculations were carried out to obtain energies and optimize the geometries of all stationary points along the pes, and determine the harmonic vibrational frequencies. two transition states (ts...