The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform
Masakatsu Ueno - One of the best experts on this subject based on the ideXlab platform.
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Transport properties of a Spherical Molecule in solvent with position-dependent viscosity
Journal of Molecular Liquids, 1995Co-Authors: Kazuyasu Ibuki, Masakatsu UenoAbstract:Abstract The rotational friction coefficient of a Spherical Molecule in solution is calculated applying the Navier-Stokes equation for a continuum solvent with a position-dependent viscosity as a model of “microscopic viscosity”. The rotational friction coefficient decreases with decreasing surface viscosity. The results are compared with the translational friction and viscosity B coefficients which are previously obtained from the same model. The B coefficient is most sensitive to a local viscosity change. The Gierer-Wirtz model overestimates the effect of the “microscopic viscosity” on the translational friction coefficient comparing with the present results.
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Effect of “Local Viscosity” on Translational Friction and Viscosity B Coefficients for a Spherical Molecule in Solution
Bulletin of the Chemical Society of Japan, 1995Co-Authors: Kazuyasu Ibuki, Masakatsu UenoAbstract:The translational friction and the viscosity B coefficients for a Spherical Molecule in solution are calculated from the Navier–Stokes equation for a continuum with space-dependent viscosity. We test three functions for the space dependence of the viscosity as models for the “local viscosity”. Each function is a smooth function of distance from the solute center and approaches the viscosity in the bulk at an infinite distance. For all the three functions studied, the translational friction and the viscosity B coefficients decrease with decreasing viscosity in the vicinity of the solute, and the effect of the space-dependent viscosity is larger for the B coefficient than for the translational friction coefficient. These results can explain the observed shortcomings of the ordinary continuum model with space-independent viscosity. This confirms the validity of the use of the viscosity B coefficient as a measure of the structure-breaking effect which is closely related to the idea of the “local viscosity”.
Tomáš Boublík - One of the best experts on this subject based on the ideXlab platform.
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ornstein zernike equation for convex Molecule mixtures
Journal of Molecular Liquids, 2004Co-Authors: Tomáš BoublíkAbstract:Abstract Structure of non-Spherical Molecule fluids is generally characterized by molecular distribution functions; in the case of fluids composed of Kihara Molecules the simpler average correlation function plays an important role in methods proposed to determine thermodynamic functions of this class of systems. The general Ornstein–Zernike (OZ) integral equation allows the determination of the molecular distribution function as a function of center-to-center distance and orientational coordinates. Recently we modified the general method in such a way that the average correlation function—which depends solely on the shortest surface–surface distance—could be obtained. The essence of the method is a separation of the shape effect of molecular cores from that due to the dependence of the distribution function on the variable distance between the pair of convex cores. The shape effect of non-Spherical convex Molecules is expressed through the third virial coefficient comprised in the O–Z convolution integral. The approach was successfully applied to several model systems of pure hard spherocylinders; in this paper, the proposed variant is extended to mixtures. We determined the average correlation functions in binary systems composed of hard spheres and hard spherocylinders. The Percus–Yevick closure was considered and the formerly used numerical solution extended to a set of integral equations. Resulting dependence of the average correlation functions on the reduced surface–surface distance agrees well with the corresponding simulation data.
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Ornstein–Zernike equation for convex Molecule mixtures
Journal of Molecular Liquids, 2004Co-Authors: Tomáš BoublíkAbstract:Abstract Structure of non-Spherical Molecule fluids is generally characterized by molecular distribution functions; in the case of fluids composed of Kihara Molecules the simpler average correlation function plays an important role in methods proposed to determine thermodynamic functions of this class of systems. The general Ornstein–Zernike (OZ) integral equation allows the determination of the molecular distribution function as a function of center-to-center distance and orientational coordinates. Recently we modified the general method in such a way that the average correlation function—which depends solely on the shortest surface–surface distance—could be obtained. The essence of the method is a separation of the shape effect of molecular cores from that due to the dependence of the distribution function on the variable distance between the pair of convex cores. The shape effect of non-Spherical convex Molecules is expressed through the third virial coefficient comprised in the O–Z convolution integral. The approach was successfully applied to several model systems of pure hard spherocylinders; in this paper, the proposed variant is extended to mixtures. We determined the average correlation functions in binary systems composed of hard spheres and hard spherocylinders. The Percus–Yevick closure was considered and the formerly used numerical solution extended to a set of integral equations. Resulting dependence of the average correlation functions on the reduced surface–surface distance agrees well with the corresponding simulation data.
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Critical properties of non-Spherical Molecule fluids from the virial expansion
Molecular Physics, 2000Co-Authors: Jiří Janeček, Tomáš BoublíkAbstract:For systems of Kihara Molecules with circular cores, the values of the reduced critical constants were determined from the fourth-order virial expansion as functions of the core diameter/thickness ratio. From expressions for the reduced functions both for the oblate and prolate shapes, the values of critical constants of four cyclic hydrocarbons and four branched alkanes were evaluated and compared with the experimental data and values obtained from the perturbation theory.
Kazuyasu Ibuki - One of the best experts on this subject based on the ideXlab platform.
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Transport properties of a Spherical Molecule in solvent with position-dependent viscosity
Journal of Molecular Liquids, 1995Co-Authors: Kazuyasu Ibuki, Masakatsu UenoAbstract:Abstract The rotational friction coefficient of a Spherical Molecule in solution is calculated applying the Navier-Stokes equation for a continuum solvent with a position-dependent viscosity as a model of “microscopic viscosity”. The rotational friction coefficient decreases with decreasing surface viscosity. The results are compared with the translational friction and viscosity B coefficients which are previously obtained from the same model. The B coefficient is most sensitive to a local viscosity change. The Gierer-Wirtz model overestimates the effect of the “microscopic viscosity” on the translational friction coefficient comparing with the present results.
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Effect of “Local Viscosity” on Translational Friction and Viscosity B Coefficients for a Spherical Molecule in Solution
Bulletin of the Chemical Society of Japan, 1995Co-Authors: Kazuyasu Ibuki, Masakatsu UenoAbstract:The translational friction and the viscosity B coefficients for a Spherical Molecule in solution are calculated from the Navier–Stokes equation for a continuum with space-dependent viscosity. We test three functions for the space dependence of the viscosity as models for the “local viscosity”. Each function is a smooth function of distance from the solute center and approaches the viscosity in the bulk at an infinite distance. For all the three functions studied, the translational friction and the viscosity B coefficients decrease with decreasing viscosity in the vicinity of the solute, and the effect of the space-dependent viscosity is larger for the B coefficient than for the translational friction coefficient. These results can explain the observed shortcomings of the ordinary continuum model with space-independent viscosity. This confirms the validity of the use of the viscosity B coefficient as a measure of the structure-breaking effect which is closely related to the idea of the “local viscosity”.
Mary C Nakamura - One of the best experts on this subject based on the ideXlab platform.
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binding and uptake of h ferritin are mediated by human transferrin receptor 1
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Li Li, Celia J Fang, James C Ryan, Erene C Niemi, Jose Lebron, Pamela J Bjorkman, Hisashi Arase, Frank M Torti, Suzy V Torti, Mary C NakamuraAbstract:Ferritin is a Spherical Molecule composed of 24 subunits of two types, ferritin H chain (FHC) and ferritin L chain (FLC). Ferritin stores iron within cells, but it also circulates and binds specifically and saturably to a variety of cell types. For most cell types, this binding can be mediated by ferritin composed only of FHC (HFt) but not by ferritin composed only of FLC (LFt), indicating that binding of ferritin to cells is mediated by FHC but not FLC. By using expression cloning, we identified human transferrin receptor-1 (TfR1) as an important receptor for HFt with little or no binding to LFt. In vitro, HFt can be precipitated by soluble TfR1, showing that this interaction is not dependent on other proteins. Binding of HFt to TfR1 is partially inhibited by diferric transferrin, but it is hindered little, if at all, by HFE. After binding of HFt to TfR1 on the cell surface, HFt enters both endosomes and lysosomes. TfR1 accounts for most, if not all, of the binding of HFt to mitogen-activated T and B cells, circulating reticulocytes, and all cell lines that we have studied. The demonstration that TfR1 can bind HFt as well as Tf raises the possibility that this dual receptor function may coordinate the processing and use of iron by these iron-binding Molecules.
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binding and uptake of h ferritin are mediated by human transferrin receptor 1
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Celia J Fang, James C Ryan, Erene C Niemi, Jose Lebron, Pamela J Bjorkman, Hisashi Arase, Frank M Torti, Suzy V Torti, Mary C Nakamura, William E SeamanAbstract:Ferritin is a Spherical Molecule composed of 24 subunits of two types, ferritin H chain (FHC) and ferritin L chain (FLC). Ferritin stores iron within cells, but it also circulates and binds specifically and saturably to a variety of cell types. For most cell types, this binding can be mediated by ferritin composed only of FHC (HFt) but not by ferritin composed only of FLC (LFt), indicating that binding of ferritin to cells is mediated by FHC but not FLC. By using expression cloning, we identified human transferrin receptor-1 (TfR1) as an important receptor for HFt with little or no binding to LFt. In vitro, HFt can be precipitated by soluble TfR1, showing that this interaction is not dependent on other proteins. Binding of HFt to TfR1 is partially inhibited by diferric transferrin, but it is hindered little, if at all, by HFE. After binding of HFt to TfR1 on the cell surface, HFt enters both endosomes and lysosomes. TfR1 accounts for most, if not all, of the binding of HFt to mitogen-activated T and B cells, circulating reticulocytes, and all cell lines that we have studied. The demonstration that TfR1 can bind HFt as well as Tf raises the possibility that this dual receptor function may coordinate the processing and use of iron by these iron-binding Molecules.
Celia J Fang - One of the best experts on this subject based on the ideXlab platform.
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binding and uptake of h ferritin are mediated by human transferrin receptor 1
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Li Li, Celia J Fang, James C Ryan, Erene C Niemi, Jose Lebron, Pamela J Bjorkman, Hisashi Arase, Frank M Torti, Suzy V Torti, Mary C NakamuraAbstract:Ferritin is a Spherical Molecule composed of 24 subunits of two types, ferritin H chain (FHC) and ferritin L chain (FLC). Ferritin stores iron within cells, but it also circulates and binds specifically and saturably to a variety of cell types. For most cell types, this binding can be mediated by ferritin composed only of FHC (HFt) but not by ferritin composed only of FLC (LFt), indicating that binding of ferritin to cells is mediated by FHC but not FLC. By using expression cloning, we identified human transferrin receptor-1 (TfR1) as an important receptor for HFt with little or no binding to LFt. In vitro, HFt can be precipitated by soluble TfR1, showing that this interaction is not dependent on other proteins. Binding of HFt to TfR1 is partially inhibited by diferric transferrin, but it is hindered little, if at all, by HFE. After binding of HFt to TfR1 on the cell surface, HFt enters both endosomes and lysosomes. TfR1 accounts for most, if not all, of the binding of HFt to mitogen-activated T and B cells, circulating reticulocytes, and all cell lines that we have studied. The demonstration that TfR1 can bind HFt as well as Tf raises the possibility that this dual receptor function may coordinate the processing and use of iron by these iron-binding Molecules.
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binding and uptake of h ferritin are mediated by human transferrin receptor 1
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Celia J Fang, James C Ryan, Erene C Niemi, Jose Lebron, Pamela J Bjorkman, Hisashi Arase, Frank M Torti, Suzy V Torti, Mary C Nakamura, William E SeamanAbstract:Ferritin is a Spherical Molecule composed of 24 subunits of two types, ferritin H chain (FHC) and ferritin L chain (FLC). Ferritin stores iron within cells, but it also circulates and binds specifically and saturably to a variety of cell types. For most cell types, this binding can be mediated by ferritin composed only of FHC (HFt) but not by ferritin composed only of FLC (LFt), indicating that binding of ferritin to cells is mediated by FHC but not FLC. By using expression cloning, we identified human transferrin receptor-1 (TfR1) as an important receptor for HFt with little or no binding to LFt. In vitro, HFt can be precipitated by soluble TfR1, showing that this interaction is not dependent on other proteins. Binding of HFt to TfR1 is partially inhibited by diferric transferrin, but it is hindered little, if at all, by HFE. After binding of HFt to TfR1 on the cell surface, HFt enters both endosomes and lysosomes. TfR1 accounts for most, if not all, of the binding of HFt to mitogen-activated T and B cells, circulating reticulocytes, and all cell lines that we have studied. The demonstration that TfR1 can bind HFt as well as Tf raises the possibility that this dual receptor function may coordinate the processing and use of iron by these iron-binding Molecules.
