The Experts below are selected from a list of 689733 Experts worldwide ranked by ideXlab platform
Hannes Jonsson - One of the best experts on this subject based on the ideXlab platform.
-
a transferable h2o Interaction Potential based on a single center multipole expansion scme
Physical Chemistry Chemical Physics, 2013Co-Authors: Kjartan Thor Wikfeldt, Enrique R Batista, Fernando D Vila, Hannes JonssonAbstract:A transferable Potential energy function for describing the Interaction between water molecules is presented. The electrostatic Interaction is described rigorously using a multipole expansion. Only one expansion center is used per molecule to avoid the introduction of monopoles. This single center approach turns out to converge and give close agreement with ab initio calculations when carried out up to and including the hexadecapole. Both dipole and quadrupole polarizability are included. All parameters in the electrostatic Interaction as well as the dispersion Interaction are taken from ab initio calculations or experimental measurements of a single water molecule. The repulsive part of the Interaction is parametrized to fit ab initio calculations of small water clusters and experimental measurements of ice Ih. The parametrized Potential function was then used to simulate liquid water and the results agree well with experiment, even better than simulations using some of the point charge Potentials fitted to liquid water. The evaluation of the new Interaction Potential for condensed phases is fast because point charges are not present and the Interaction can, to a good approximation, be truncated at a finite range.
-
a transferable h2o Interaction Potential based on a single center multipole expansion scme
arXiv: Chemical Physics, 2013Co-Authors: Kjartan Thor Wikfeldt, Enrique R Batista, Fernando D Vila, Hannes JonssonAbstract:A transferable Potential energy function for describing the Interaction between water molecules is presented. The electrostatic Interaction is described rigorously using a multipole expansion. Only one expansion center is used per molecule to avoid the introduction of monopoles. This single center approach turns out to converge and give close agreement with ab initio calculations when carried out up to and including the hexadecapole. Both dipole and quadrupole polarizability is included. All parameters in the electrostatic Interaction as well as the dispersion Interaction are taken from ab initio calculations or experimental measurements of a single water molecule. The repulsive part of the Interaction is parametrized to fit ab initio calculations of small water clusters and experimental measurements of ice Ih. The parametrized Potential function was then used to simulate liquid water and the results agree well with experiment, even better than simulations using some of the point charge Potentials fitted to liquid water. The evaluation of the new Interaction Potential for condensed phases is fast because point charges are not present and the Interaction can, to a good approximation, be truncated at a finite range.
Paul M Silber - One of the best experts on this subject based on the ideXlab platform.
-
cryopreserved human hepatocytes characterization of drug metabolizing activities and applications in higher throughput screening assays for hepatotoxicity metabolic stability and drug drug Interaction Potential
Chemico-Biological Interactions, 1999Co-Authors: Albert P Li, Chuang Lu, Julie A Brent, Chuong Pham, Andrew Fackett, Charles E Ruegg, Paul M SilberAbstract:Abstract Cryopreserved human hepatocytes were extensively characterized in our laboratory. The post-thaw viability, as determined by Trypan blue exclusion, ranged from, the viability, measured via dye exclusion, ranged from 55 to 83% for hepatocytes cryopreserved from 17 donors. Post-thaw viability and yield (viable cells per vial) were found to be stable up to the longest storage duration evaluated of 120 days. Drug-metabolizing enzyme activities of the cryopreserved hepatocytes (mean of ten donors) as percentages of the freshly isolated cells were: 97% for cytochrome P450 isoform (CYP) 1A2, 78% for CYP2A6, 96% for CYP2C9, 86% for CYP2Cl9, 90% for CYP2D6, 164% for CYP3A4, 76% for UDP-glucuronidase, and 88% for umbelliferone sulfotransferase. Known species-differences in 7-ethoxycoumarin (7-EC) metabolism were reproduced by cryopreserved hepatocytes from human, rat, rabbit, dog, and monkey, illustrating the utility of cryopreserved hepatocytes from multiple animal species in the evaluation of species-differences in drug metabolism. Higher throughput screening (HTS) assays were developed using cryopreserved human hepatocytes for hepatotoxicity, metabolic stability, and inhibitory drug–drug Interactions. Dose-dependent cytotoxicity, measured using MTT metabolism as an endpoint, was observed for the known hepatotoxic chemicals tamoxifen, clozapine, cadmium chloride, diclofenac, amiodarone, tranylcypromine, precocene II, but not for 2-thiouracil. Cell density- and time-dependent metabolism of 7-EC and dextromethorphan were observed in the HTS assay for metabolic stability. Known CYP isoform-specific inhibitors were evaluated in the HTS assay for inhibitory drug–drug Interactions. Furafylline, sulfaphenazole, quinidine, and ketoconazole were found to be specific inhibitors of CYP1A2, CYP2C9, CYP2D6, and CYP3A4, respectively. Tranylcypromine and diethyldithiocarbamate were found to be less specific, with inhibitory effects towards several CYP isoforms, including CYP2A6, CYP2C9, CYP2Cl9, and CYP2E1. These results suggest that cryopreserved human hepatocytes represent a useful experimental tool for the evaluation of drug metabolism, toxicity, and inhibitory drug–drug Interaction Potential.
-
cryopreserved human hepatocytes characterization of drug metabolizing activities and applications in higher throughput screening assays for hepatotoxicity metabolic stability and drug drug Interaction Potential
Chemico-Biological Interactions, 1999Co-Authors: Julie A Brent, Chuong Pham, Andrew Fackett, Charles E Ruegg, Paul M SilberAbstract:Cryopreserved human hepatocytes were extensively characterized in our laboratory. The post-thaw viability, measured via dye exclusion, ranged from 55 to 83%, for hepatocytes cryopreserved from 17 donors. Post-thaw viability and yield (viable cells per vial) were found to be stable up to the longest storage duration evaluated of 120 days. Drug-metabolizing enzyme activities of the cryopreserved hepatocytes (mean of ten donors) as percentages of the freshly isolated cells were: 97%, for cytochrome P450 isoform (CYP) 1A2, 78% for CYP2A6, 96% for CYP2C9. 86% for CYP2Cl9, 90% for CYP2D6, 164% for CYP3A4, 76% for UDP-glucuronidase, and 88% for umbelliferone sulfotransferase. Known species-differences in 7-ethoxycoumarin (7-EC) metabolism were reproduced by cryopreserved hepatocytes from human, rat, rabbit, dog, and monkey, illustrating the utility of cryopreserved hepatocytes from multiple animal species in the evaluation of species-differences in drug metabolism. Higher throughput screening (HTS) assays were developed using cryopreserved human hepatocytes for hepatotoxicity, metabolic stability, and inhibitory drug-drug Interactions. Dose-dependent cytotoxicity, measured using MTT metabolism as an endpoint, was observed for the known hepatotoxic chemicals tamoxifen, clozapine, cadmium chloride, diclofenac, amiodarone, tranylcypromine, precocene II, but not for 2-thiouracil. Cell density- and time-dependent metabolism of 7-EC and dextromethorphan were observed in the HTS assay for metabolic stability. Known CYP isoform-specific inhibitors were evaluated in the HTS assay for inhibitory drug-drug Interactions. Furafylline, sulfaphenazole, quinidine, and ketoconazole were found to be specific inhibitors of CYP1A2, CYP2C9, CYP2D6, and CYP3A4, respectively. Tranylcypromine and diethyldithiocarbamate were found to be less specific, with inhibitory effects towards several CYP isoforms, including CYP2A6, CYP2C9, CYP2C19, and CYP2E1. These results suggest that cryopreserved human hepatocytes represent a useful experimental tool for the evaluation of drug metabolism, toxicity, and inhibitory drug-drug Interaction Potential.
-
cryopreserved human hepatocytes characterization of drug metabolizing enzyme activities and applications in higher throughput screening assays for hepatotoxicity metabolic stability and drug drug Interaction Potential
Chemico-Biological Interactions, 1999Co-Authors: Julie A Brent, Chuong Pham, Andrew Fackett, Charles E Ruegg, Paul M SilberAbstract:Cryopreserved human hepatocytes were extensively characterized in our laboratory. The post-thaw viability, measured via dye exclusion, ranged from 55 to 83%, for hepatocytes cryopreserved from 17 donors. Post-thaw viability and yield (viable cells per vial) were found to be stable up to the longest storage duration evaluated of 120 days. Drug-metabolizing enzyme activities of the cryopreserved hepatocytes (mean of ten donors) as percentages of the freshly isolated cells were: 97%, for cytochrome P450 isoform (CYP) 1A2, 78% for CYP2A6, 96% for CYP2C9. 86% for CYP2Cl9, 90% for CYP2D6, 164% for CYP3A4, 76% for UDP-glucuronidase, and 88% for umbelliferone sulfotransferase. Known species-differences in 7-ethoxycoumarin (7-EC) metabolism were reproduced by cryopreserved hepatocytes from human, rat, rabbit, dog, and monkey, illustrating the utility of cryopreserved hepatocytes from multiple animal species in the evaluation of species-differences in drug metabolism. Higher throughput screening (HTS) assays were developed using cryopreserved human hepatocytes for hepatotoxicity, metabolic stability, and inhibitory drug-drug Interactions. Dose-dependent cytotoxicity, measured using MTT metabolism as an endpoint, was observed for the known hepatotoxic chemicals tamoxifen, clozapine, cadmium chloride, diclofenac, amiodarone, tranylcypromine, precocene II, but not for 2-thiouracil. Cell density- and time-dependent metabolism of 7-EC and dextromethorphan were observed in the HTS assay for metabolic stability. Known CYP isoform-specific inhibitors were evaluated in the HTS assay for inhibitory drug-drug Interactions. Furafylline, sulfaphenazole, quinidine, and ketoconazole were found to be specific inhibitors of CYP1A2, CYP2C9, CYP2D6, and CYP3A4, respectively. Tranylcypromine and diethyldithiocarbamate were found to be less specific, with inhibitory effects towards several CYP isoforms, including CYP2A6, CYP2C9, CYP2C19, and CYP2E1. These results suggest that cryopreserved human hepatocytes represent a useful experimental tool for the evaluation of drug metabolism, toxicity, and inhibitory drug-drug Interaction Potential.
Kjartan Thor Wikfeldt - One of the best experts on this subject based on the ideXlab platform.
-
a transferable h2o Interaction Potential based on a single center multipole expansion scme
Physical Chemistry Chemical Physics, 2013Co-Authors: Kjartan Thor Wikfeldt, Enrique R Batista, Fernando D Vila, Hannes JonssonAbstract:A transferable Potential energy function for describing the Interaction between water molecules is presented. The electrostatic Interaction is described rigorously using a multipole expansion. Only one expansion center is used per molecule to avoid the introduction of monopoles. This single center approach turns out to converge and give close agreement with ab initio calculations when carried out up to and including the hexadecapole. Both dipole and quadrupole polarizability are included. All parameters in the electrostatic Interaction as well as the dispersion Interaction are taken from ab initio calculations or experimental measurements of a single water molecule. The repulsive part of the Interaction is parametrized to fit ab initio calculations of small water clusters and experimental measurements of ice Ih. The parametrized Potential function was then used to simulate liquid water and the results agree well with experiment, even better than simulations using some of the point charge Potentials fitted to liquid water. The evaluation of the new Interaction Potential for condensed phases is fast because point charges are not present and the Interaction can, to a good approximation, be truncated at a finite range.
-
a transferable h2o Interaction Potential based on a single center multipole expansion scme
arXiv: Chemical Physics, 2013Co-Authors: Kjartan Thor Wikfeldt, Enrique R Batista, Fernando D Vila, Hannes JonssonAbstract:A transferable Potential energy function for describing the Interaction between water molecules is presented. The electrostatic Interaction is described rigorously using a multipole expansion. Only one expansion center is used per molecule to avoid the introduction of monopoles. This single center approach turns out to converge and give close agreement with ab initio calculations when carried out up to and including the hexadecapole. Both dipole and quadrupole polarizability is included. All parameters in the electrostatic Interaction as well as the dispersion Interaction are taken from ab initio calculations or experimental measurements of a single water molecule. The repulsive part of the Interaction is parametrized to fit ab initio calculations of small water clusters and experimental measurements of ice Ih. The parametrized Potential function was then used to simulate liquid water and the results agree well with experiment, even better than simulations using some of the point charge Potentials fitted to liquid water. The evaluation of the new Interaction Potential for condensed phases is fast because point charges are not present and the Interaction can, to a good approximation, be truncated at a finite range.
Julie A Brent - One of the best experts on this subject based on the ideXlab platform.
-
cryopreserved human hepatocytes characterization of drug metabolizing activities and applications in higher throughput screening assays for hepatotoxicity metabolic stability and drug drug Interaction Potential
Chemico-Biological Interactions, 1999Co-Authors: Albert P Li, Chuang Lu, Julie A Brent, Chuong Pham, Andrew Fackett, Charles E Ruegg, Paul M SilberAbstract:Abstract Cryopreserved human hepatocytes were extensively characterized in our laboratory. The post-thaw viability, as determined by Trypan blue exclusion, ranged from, the viability, measured via dye exclusion, ranged from 55 to 83% for hepatocytes cryopreserved from 17 donors. Post-thaw viability and yield (viable cells per vial) were found to be stable up to the longest storage duration evaluated of 120 days. Drug-metabolizing enzyme activities of the cryopreserved hepatocytes (mean of ten donors) as percentages of the freshly isolated cells were: 97% for cytochrome P450 isoform (CYP) 1A2, 78% for CYP2A6, 96% for CYP2C9, 86% for CYP2Cl9, 90% for CYP2D6, 164% for CYP3A4, 76% for UDP-glucuronidase, and 88% for umbelliferone sulfotransferase. Known species-differences in 7-ethoxycoumarin (7-EC) metabolism were reproduced by cryopreserved hepatocytes from human, rat, rabbit, dog, and monkey, illustrating the utility of cryopreserved hepatocytes from multiple animal species in the evaluation of species-differences in drug metabolism. Higher throughput screening (HTS) assays were developed using cryopreserved human hepatocytes for hepatotoxicity, metabolic stability, and inhibitory drug–drug Interactions. Dose-dependent cytotoxicity, measured using MTT metabolism as an endpoint, was observed for the known hepatotoxic chemicals tamoxifen, clozapine, cadmium chloride, diclofenac, amiodarone, tranylcypromine, precocene II, but not for 2-thiouracil. Cell density- and time-dependent metabolism of 7-EC and dextromethorphan were observed in the HTS assay for metabolic stability. Known CYP isoform-specific inhibitors were evaluated in the HTS assay for inhibitory drug–drug Interactions. Furafylline, sulfaphenazole, quinidine, and ketoconazole were found to be specific inhibitors of CYP1A2, CYP2C9, CYP2D6, and CYP3A4, respectively. Tranylcypromine and diethyldithiocarbamate were found to be less specific, with inhibitory effects towards several CYP isoforms, including CYP2A6, CYP2C9, CYP2Cl9, and CYP2E1. These results suggest that cryopreserved human hepatocytes represent a useful experimental tool for the evaluation of drug metabolism, toxicity, and inhibitory drug–drug Interaction Potential.
-
cryopreserved human hepatocytes characterization of drug metabolizing activities and applications in higher throughput screening assays for hepatotoxicity metabolic stability and drug drug Interaction Potential
Chemico-Biological Interactions, 1999Co-Authors: Julie A Brent, Chuong Pham, Andrew Fackett, Charles E Ruegg, Paul M SilberAbstract:Cryopreserved human hepatocytes were extensively characterized in our laboratory. The post-thaw viability, measured via dye exclusion, ranged from 55 to 83%, for hepatocytes cryopreserved from 17 donors. Post-thaw viability and yield (viable cells per vial) were found to be stable up to the longest storage duration evaluated of 120 days. Drug-metabolizing enzyme activities of the cryopreserved hepatocytes (mean of ten donors) as percentages of the freshly isolated cells were: 97%, for cytochrome P450 isoform (CYP) 1A2, 78% for CYP2A6, 96% for CYP2C9. 86% for CYP2Cl9, 90% for CYP2D6, 164% for CYP3A4, 76% for UDP-glucuronidase, and 88% for umbelliferone sulfotransferase. Known species-differences in 7-ethoxycoumarin (7-EC) metabolism were reproduced by cryopreserved hepatocytes from human, rat, rabbit, dog, and monkey, illustrating the utility of cryopreserved hepatocytes from multiple animal species in the evaluation of species-differences in drug metabolism. Higher throughput screening (HTS) assays were developed using cryopreserved human hepatocytes for hepatotoxicity, metabolic stability, and inhibitory drug-drug Interactions. Dose-dependent cytotoxicity, measured using MTT metabolism as an endpoint, was observed for the known hepatotoxic chemicals tamoxifen, clozapine, cadmium chloride, diclofenac, amiodarone, tranylcypromine, precocene II, but not for 2-thiouracil. Cell density- and time-dependent metabolism of 7-EC and dextromethorphan were observed in the HTS assay for metabolic stability. Known CYP isoform-specific inhibitors were evaluated in the HTS assay for inhibitory drug-drug Interactions. Furafylline, sulfaphenazole, quinidine, and ketoconazole were found to be specific inhibitors of CYP1A2, CYP2C9, CYP2D6, and CYP3A4, respectively. Tranylcypromine and diethyldithiocarbamate were found to be less specific, with inhibitory effects towards several CYP isoforms, including CYP2A6, CYP2C9, CYP2C19, and CYP2E1. These results suggest that cryopreserved human hepatocytes represent a useful experimental tool for the evaluation of drug metabolism, toxicity, and inhibitory drug-drug Interaction Potential.
-
cryopreserved human hepatocytes characterization of drug metabolizing enzyme activities and applications in higher throughput screening assays for hepatotoxicity metabolic stability and drug drug Interaction Potential
Chemico-Biological Interactions, 1999Co-Authors: Julie A Brent, Chuong Pham, Andrew Fackett, Charles E Ruegg, Paul M SilberAbstract:Cryopreserved human hepatocytes were extensively characterized in our laboratory. The post-thaw viability, measured via dye exclusion, ranged from 55 to 83%, for hepatocytes cryopreserved from 17 donors. Post-thaw viability and yield (viable cells per vial) were found to be stable up to the longest storage duration evaluated of 120 days. Drug-metabolizing enzyme activities of the cryopreserved hepatocytes (mean of ten donors) as percentages of the freshly isolated cells were: 97%, for cytochrome P450 isoform (CYP) 1A2, 78% for CYP2A6, 96% for CYP2C9. 86% for CYP2Cl9, 90% for CYP2D6, 164% for CYP3A4, 76% for UDP-glucuronidase, and 88% for umbelliferone sulfotransferase. Known species-differences in 7-ethoxycoumarin (7-EC) metabolism were reproduced by cryopreserved hepatocytes from human, rat, rabbit, dog, and monkey, illustrating the utility of cryopreserved hepatocytes from multiple animal species in the evaluation of species-differences in drug metabolism. Higher throughput screening (HTS) assays were developed using cryopreserved human hepatocytes for hepatotoxicity, metabolic stability, and inhibitory drug-drug Interactions. Dose-dependent cytotoxicity, measured using MTT metabolism as an endpoint, was observed for the known hepatotoxic chemicals tamoxifen, clozapine, cadmium chloride, diclofenac, amiodarone, tranylcypromine, precocene II, but not for 2-thiouracil. Cell density- and time-dependent metabolism of 7-EC and dextromethorphan were observed in the HTS assay for metabolic stability. Known CYP isoform-specific inhibitors were evaluated in the HTS assay for inhibitory drug-drug Interactions. Furafylline, sulfaphenazole, quinidine, and ketoconazole were found to be specific inhibitors of CYP1A2, CYP2C9, CYP2D6, and CYP3A4, respectively. Tranylcypromine and diethyldithiocarbamate were found to be less specific, with inhibitory effects towards several CYP isoforms, including CYP2A6, CYP2C9, CYP2C19, and CYP2E1. These results suggest that cryopreserved human hepatocytes represent a useful experimental tool for the evaluation of drug metabolism, toxicity, and inhibitory drug-drug Interaction Potential.
Jose Pedro Rino - One of the best experts on this subject based on the ideXlab platform.
-
an Interaction Potential for barium sulfide a molecular dynamics study
Computational Materials Science, 2014Co-Authors: Jose Pedro RinoAbstract:Structural, dynamical and thermodynamic properties of barium sulfide, as well as the structural transformation induced by pressure, are investigated in a molecular dynamics simulation based on an effective two-body interatomic Potential. The two-body interatomic Potential proposed for BaS is made up of steric repulsions, Coulomb Interactions due to charge transfer, charge-induced dipole attractions due to the electronic polarizability and van der Waals attraction. The stability of the most stable phases of this compound, the vibrational density of states, heat capacity as a function of temperature, melting and recrystallization, as well as the structural phase transformation induced by pressure, are correctly described. It is shown that this phase transformation depends strongly on the temperature and crystallinity of the material. The simulated results are compared with experimental observations and other calculations reported in the literature.
-
Interaction Potential for aluminum nitride a molecular dynamics study of mechanical and thermal properties of crystalline and amorphous aluminum nitride
Journal of Applied Physics, 2011Co-Authors: Priya Vashishta, Rajiv K Kalia, Aiichiro Nakano, Jose Pedro RinoAbstract:An effective interatomic Interaction Potential for AlN is proposed. The Potential consists of two-body and three-body covalent Interactions. The two-body Potential includes steric repulsions due to atomic sizes, Coulomb Interactions resulting from charge transfer between atoms, charge-induced dipole-Interactions due to the electronic polarizability of ions, and induced dipole–dipole (van der Waals) Interactions. The covalent characters of the Al–N–Al and N–Al–N bonds are described by the three-body Potential. The proposed three-body Interaction Potential is a modification of the Stillinger–Weber form proposed to describe Si. Using the molecular dynamics method, the Interaction Potential is used to study structural, elastic, and dynamical properties of crystalline and amorphous states of AlN for several densities and temperatures. The structural energy for wurtzite (2H) structure has the lowest energy, followed zinc-blende and rock-salt (RS) structures. The pressure for the structural transformation from w...
-
Interaction Potential for silicon carbide a molecular dynamics study of elastic constants and vibrational density of states for crystalline and amorphous silicon carbide
Journal of Applied Physics, 2007Co-Authors: Priya Vashishta, Rajiv K Kalia, Aiichiro Nakano, Jose Pedro RinoAbstract:An effective interatomic Interaction Potential for SiC is proposed. The Potential consists of two-body and three-body covalent Interactions. The two-body Potential includes steric repulsions due to atomic sizes, Coulomb Interactions resulting from charge transfer between atoms, charge-induced dipole-Interactions due to the electronic polarizability of ions, and induced dipole-dipole (van der Waals) Interactions. The covalent characters of the Si–C–Si and C–Si–C bonds are described by the three-body Potential. The proposed three-body Interaction Potential is a modification of the Stillinger-Weber form proposed to describe Si. Using the molecular dynamics method, the Interaction Potential is used to study structural, elastic, and dynamical properties of crystalline (3C), amorphous, and liquid states of SiC for several densities and temperatures. The structural energy for cubic (3C) structure has the lowest energy, followed by the wurtzite (2H) and rock-salt (RS) structures. The pressure for the structural t...
