The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform
Benoit Roux - One of the best experts on this subject based on the ideXlab platform.
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Simulation of Osmotic Pressure in concentrated aqueous salt solutions
Journal of Physical Chemistry Letters, 2010Co-Authors: Yun Luo, Benoit RouxAbstract:Accurate force fields are critical for meaningful simulation studies of highly concentrated electrolytes. The ion models that are widely used in biomolecular simulations do not necessarily reproduce the correct behavior at finite concentrations. In principle, the Osmotic Pressure is a key thermodynamic property that could be used to test and refine force field parameters for concentrated solutions. Here we describe a novel, simple, and practical method to compute the Osmotic Pressure directly from molecular dynamics (MD) simulation of concentrated aqueous solutions by introducing an idealized semipermeable membrane. Simple models for Na+, K+, and Cl? are tested and calibrated to accurately reproduce the experimental Osmotic Pressure at high salt concentration, up to the solubility limit of 4?5 M. The methodology is general and can be extended to any type of solute as well as nonadditive polarizable force fields.
Andrea Grafmüller - One of the best experts on this subject based on the ideXlab platform.
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efficient Osmotic Pressure calculations using coarse grained molecular simulations
Journal of Chemical Theory and Computation, 2018Co-Authors: Jörg Sauter, Andrea GrafmüllerAbstract:Osmotic Pressure data is increasingly used to parametrize all-atom simulation Force Fields (FFs), leading to large computational cost for larger molecules. Here, we show that the Osmotic Pressure can be calculated precisely using transferable coarse-grained FFs obtained from short atomistic simulations using an inhomogeneously regularized coarse-graining procedure. This is demonstrated for carbohydrates, where compared to the equivalent atomistic system, an increase of the computational efficiency by a factor of ≈500 is achieved.
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Predicting the Chemical Potential and Osmotic Pressure of Polysaccharide Solutions by Molecular Simulations.
Journal of Chemical Theory and Computation, 2016Co-Authors: Jörg Sauter, Andrea GrafmüllerAbstract:Differences in the chemical potential of water and the resulting Osmotic Pressure across semipermeable membranes are of fundamental importance for many biological systems. Here, we calculate the Osmotic Pressure and the chemical potential of water for polysaccharide solutions by molecular simulations. We set up a method to measure the Osmotic Pressure in polysaccharide systems at different concentrations and found that for monomers the experimental trend with respect to the solute concentration is reproduced correctly. However, the calculated Osmotic Pressure values are systematically too low, and two common carbohydrate force fields (FFs) cannot correctly describe the relationship between the Osmotic Pressure and the degree of polymerization. Therefore, we reparametrized parts of the GLYCAM06 TIP5P FF based on Osmotic Pressure data. The predictive power of the resulting GLYCAM06OSMOr14TIP5P FF is demonstrated for two different sugar molecules over a wide range of concentrations, and additional evaluation...
Yun Luo - One of the best experts on this subject based on the ideXlab platform.
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Simulation of Osmotic Pressure in concentrated aqueous salt solutions
Journal of Physical Chemistry Letters, 2010Co-Authors: Yun Luo, Benoit RouxAbstract:Accurate force fields are critical for meaningful simulation studies of highly concentrated electrolytes. The ion models that are widely used in biomolecular simulations do not necessarily reproduce the correct behavior at finite concentrations. In principle, the Osmotic Pressure is a key thermodynamic property that could be used to test and refine force field parameters for concentrated solutions. Here we describe a novel, simple, and practical method to compute the Osmotic Pressure directly from molecular dynamics (MD) simulation of concentrated aqueous solutions by introducing an idealized semipermeable membrane. Simple models for Na+, K+, and Cl? are tested and calibrated to accurately reproduce the experimental Osmotic Pressure at high salt concentration, up to the solubility limit of 4?5 M. The methodology is general and can be extended to any type of solute as well as nonadditive polarizable force fields.
Jörg Sauter - One of the best experts on this subject based on the ideXlab platform.
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efficient Osmotic Pressure calculations using coarse grained molecular simulations
Journal of Chemical Theory and Computation, 2018Co-Authors: Jörg Sauter, Andrea GrafmüllerAbstract:Osmotic Pressure data is increasingly used to parametrize all-atom simulation Force Fields (FFs), leading to large computational cost for larger molecules. Here, we show that the Osmotic Pressure can be calculated precisely using transferable coarse-grained FFs obtained from short atomistic simulations using an inhomogeneously regularized coarse-graining procedure. This is demonstrated for carbohydrates, where compared to the equivalent atomistic system, an increase of the computational efficiency by a factor of ≈500 is achieved.
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Predicting the Chemical Potential and Osmotic Pressure of Polysaccharide Solutions by Molecular Simulations.
Journal of Chemical Theory and Computation, 2016Co-Authors: Jörg Sauter, Andrea GrafmüllerAbstract:Differences in the chemical potential of water and the resulting Osmotic Pressure across semipermeable membranes are of fundamental importance for many biological systems. Here, we calculate the Osmotic Pressure and the chemical potential of water for polysaccharide solutions by molecular simulations. We set up a method to measure the Osmotic Pressure in polysaccharide systems at different concentrations and found that for monomers the experimental trend with respect to the solute concentration is reproduced correctly. However, the calculated Osmotic Pressure values are systematically too low, and two common carbohydrate force fields (FFs) cannot correctly describe the relationship between the Osmotic Pressure and the degree of polymerization. Therefore, we reparametrized parts of the GLYCAM06 TIP5P FF based on Osmotic Pressure data. The predictive power of the resulting GLYCAM06OSMOr14TIP5P FF is demonstrated for two different sugar molecules over a wide range of concentrations, and additional evaluation...
Huachang Hong - One of the best experts on this subject based on the ideXlab platform.
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Experimental evidence for Osmotic Pressure-induced fouling in a membrane bioreactor.
Bioresource Technology, 2014Co-Authors: Meijia Zhang, Fangyuan Wang, Yiming He, Jianrong Chen, Huachang Hong, Ai-jun Wang, Haiying YuAbstract:Abstract A lab-scale membrane bioreactor (MBR) was continuously operated to investigate the membrane fouling. A new membrane fouling mechanism: Osmotic Pressure mechanism in cake layer filtration process was identified. Osmotic Pressure was proposed to stem from the retention of counter-ions in the matrix of biopolymers in cake layer. Through Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analyzes, it was found that functional groups were abundant in the surface of cake layer. Batch filtration tests showed that soluble microbial products (SMP) and biopolymer clusters (BPC) in the supernatant played key roles in Osmotic Pressure mechanism, and were thus largely responsible for the high cake resistance. The chemical potential of water varied along with cake depth. The formed cake layer was found to be much hydrated and elastic. These findings provided the direct evidence for the existence of Osmotic Pressure mechanism.
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Osmotic Pressure effect on membrane fouling in a submerged anaerobic membrane bioreactor and its experimental verification
Bioresource Technology, 2012Co-Authors: Jianrong Chen, Meijia Zhang, Ai-jun Wang, Hongjun Lin, Huachang HongAbstract:A laboratory-scale submerged anaerobic membrane bioreactor (SAnMBR) treating sewage was used to investigate the membrane fouling mechanism. Characterization of cake layer formed on membrane surface showed that cake layer was hydrated, rich of extracellular polymeric substances (EPS) and negative charged with the charge density of 0.21-0.46 meq/kg MLSS. Detailed analysis revealed a new membrane fouling mechanism, Osmotic Pressure during cake layer filtration process due to the interception of ions. An Osmotic Pressure model was then developed to elaborate the existence of Osmotic Pressure and to estimate the contribution of Osmotic Pressure to membrane fouling. The calculated results showed that Osmotic Pressure accounted for the largest fraction of total operation Pressure, indicating that Osmotic Pressure generated by the retained ions was one of the major mechanisms responsible for membrane fouling problem in MBRs. These findings provided a new insight into membrane fouling in MBRs. (C) 2012 Elsevier Ltd. All rights reserved.
