The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Ralf Metzler - One of the best experts on this subject based on the ideXlab platform.
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Bulk mediated Diffusion on a planar surface full solution
Physical Review E, 2012Co-Authors: Aleksei V Chechkin, Irwin M Zaid, Michael A Lomholt, I M Sokolov, Ralf MetzlerAbstract:We consider the effective surface motion of a particle that intermittently unbinds from a planar surface and performs Bulk excursions. Based on a random-walk approach, we derive the Diffusion equations for surface and Bulk Diffusion including the surface-Bulk coupling. From these exact dynamic equations, we analytically obtain the propagator of the effective surface motion. This approach allows us to deduce a superdiffusive, Cauchy-type behavior on the surface, together with exact cutoffs limiting the Cauchy form. Moreover, we study the long-time dynamics for the surface motion.
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effective surface motion on a reactive cylinder of particles that perform intermittent Bulk Diffusion
Journal of Chemical Physics, 2011Co-Authors: Aleksei V Chechkin, Irwin M Zaid, Michael A Lomholt, I M Sokolov, Ralf MetzlerAbstract:In many biological and small scale technological applications particles may transiently bind to a cylindrical surface. In between two binding events the particles diffuse in the Bulk, thus producing an effective translation on the cylindrical surface. We here derive the effective motion on the surface allowing for additional Diffusion on the cylindrical surface itself. We find explicit solutions for the number of adsorbed particles at one given instant, the effective surface displacement, as well as the surface propagator. In particular sub- and superdiffusive regimes are found, as well as an effective stalling of Diffusion visible as a plateau in the mean squared displacement. We also investigate the corresponding first passage problem.
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effective surface motion on a reactive cylinder of particles that perform intermittent Bulk Diffusion
arXiv: Statistical Mechanics, 2011Co-Authors: Aleksei V Chechkin, Irwin M Zaid, Michael A Lomholt, I M Sokolov, Ralf MetzlerAbstract:In many biological and small scale technological applications particles may transiently bind to a cylindrical surface. In between two binding events the particles diffuse in the Bulk, thus producing an effective translation on the cylinder surface. We here derive the effective motion on the surface, allowing for additional Diffusion on the cylinder surface itself. We find explicit solutions for the number of adsorbed particles at one given instant, the effective surface displacement, as well as the surface propagator. In particular sub- and superdiffusive regimes are found, as well as an effective stalling of Diffusion visible as a plateau in the mean squared displacement. We also investigate the corresponding first passage and first return problems.
Matthias Roger - One of the best experts on this subject based on the ideXlab platform.
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a coupled surface cahn hilliard Bulk Diffusion system modeling lipid raft formation in cell membranes
Mathematical Models and Methods in Applied Sciences, 2016Co-Authors: Harald Garcke, Johannes Kampmann, Andreas Ratz, Matthias RogerAbstract:We propose and investigate a model for lipid raft formation and dynamics in biological membranes. The model describes the lipid composition of the membrane and an interaction with cholesterol. To account for cholesterol exchange between cytosol and cell membrane we couple a Bulk-Diffusion to an evolution equation on the membrane. The latter describes the relaxation dynamics for an energy which takes lipid–phase separation and lipid–cholesterol interaction energy into account. It takes the form of an (extended) Cahn–Hilliard equation. Different laws for the exchange term represent equilibrium and nonequilibrium models. We present a thermodynamic justification, analyze the respective qualitative behavior and derive asymptotic reductions of the model. In particular we present a formal asymptotic expansion near the sharp interface limit, where the membrane is separated into two pure phases of saturated and unsaturated lipids, respectively. Finally we perform numerical simulations and investigate the long-time...
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a coupled surface cahn hilliard Bulk Diffusion system modeling lipid raft formation in cell membranes
arXiv: Analysis of PDEs, 2015Co-Authors: Harald Garcke, Johannes Kampmann, Andreas Ratz, Matthias RogerAbstract:We propose and investigate a model for lipid raft formation and dynamics in biological membranes. The model describes the lipid composition of the membrane and an interaction with cholesterol. To account for cholesterol exchange between cytosol and cell membrane we couple a Bulk-Diffusion to an evolution equation on the membrane. The latter describes a relaxation dynamics for an energy taking lipid-phase separation and lipid-cholesterol interaction energy into account. It takes the form of an (extended) Cahn--Hilliard equation. Different laws for the exchange term represent equilibrium and non-equilibrium models. We present a thermodynamic justification, analyze the respective qualitative behavior and derive asymptotic reductions of the model. In particular we present a formal asymptotic expansion near the sharp interface limit, where the membrane is separated into two pure phases of saturated and unsaturated lipids, respectively. Finally we perform numerical simulations and investigate the long-time behavior of the model and its parameter dependence. Both the mathematical analysis and the numerical simulations show the emergence of raft-like structures in the non-equilibrium case whereas in the equilibrium case only macrodomains survive in the long-time evolution.
Harald Garcke - One of the best experts on this subject based on the ideXlab platform.
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a coupled surface cahn hilliard Bulk Diffusion system modeling lipid raft formation in cell membranes
Mathematical Models and Methods in Applied Sciences, 2016Co-Authors: Harald Garcke, Johannes Kampmann, Andreas Ratz, Matthias RogerAbstract:We propose and investigate a model for lipid raft formation and dynamics in biological membranes. The model describes the lipid composition of the membrane and an interaction with cholesterol. To account for cholesterol exchange between cytosol and cell membrane we couple a Bulk-Diffusion to an evolution equation on the membrane. The latter describes the relaxation dynamics for an energy which takes lipid–phase separation and lipid–cholesterol interaction energy into account. It takes the form of an (extended) Cahn–Hilliard equation. Different laws for the exchange term represent equilibrium and nonequilibrium models. We present a thermodynamic justification, analyze the respective qualitative behavior and derive asymptotic reductions of the model. In particular we present a formal asymptotic expansion near the sharp interface limit, where the membrane is separated into two pure phases of saturated and unsaturated lipids, respectively. Finally we perform numerical simulations and investigate the long-time...
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a coupled surface cahn hilliard Bulk Diffusion system modeling lipid raft formation in cell membranes
arXiv: Analysis of PDEs, 2015Co-Authors: Harald Garcke, Johannes Kampmann, Andreas Ratz, Matthias RogerAbstract:We propose and investigate a model for lipid raft formation and dynamics in biological membranes. The model describes the lipid composition of the membrane and an interaction with cholesterol. To account for cholesterol exchange between cytosol and cell membrane we couple a Bulk-Diffusion to an evolution equation on the membrane. The latter describes a relaxation dynamics for an energy taking lipid-phase separation and lipid-cholesterol interaction energy into account. It takes the form of an (extended) Cahn--Hilliard equation. Different laws for the exchange term represent equilibrium and non-equilibrium models. We present a thermodynamic justification, analyze the respective qualitative behavior and derive asymptotic reductions of the model. In particular we present a formal asymptotic expansion near the sharp interface limit, where the membrane is separated into two pure phases of saturated and unsaturated lipids, respectively. Finally we perform numerical simulations and investigate the long-time behavior of the model and its parameter dependence. Both the mathematical analysis and the numerical simulations show the emergence of raft-like structures in the non-equilibrium case whereas in the equilibrium case only macrodomains survive in the long-time evolution.
Aleksei V Chechkin - One of the best experts on this subject based on the ideXlab platform.
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Bulk mediated Diffusion on a planar surface full solution
Physical Review E, 2012Co-Authors: Aleksei V Chechkin, Irwin M Zaid, Michael A Lomholt, I M Sokolov, Ralf MetzlerAbstract:We consider the effective surface motion of a particle that intermittently unbinds from a planar surface and performs Bulk excursions. Based on a random-walk approach, we derive the Diffusion equations for surface and Bulk Diffusion including the surface-Bulk coupling. From these exact dynamic equations, we analytically obtain the propagator of the effective surface motion. This approach allows us to deduce a superdiffusive, Cauchy-type behavior on the surface, together with exact cutoffs limiting the Cauchy form. Moreover, we study the long-time dynamics for the surface motion.
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effective surface motion on a reactive cylinder of particles that perform intermittent Bulk Diffusion
Journal of Chemical Physics, 2011Co-Authors: Aleksei V Chechkin, Irwin M Zaid, Michael A Lomholt, I M Sokolov, Ralf MetzlerAbstract:In many biological and small scale technological applications particles may transiently bind to a cylindrical surface. In between two binding events the particles diffuse in the Bulk, thus producing an effective translation on the cylindrical surface. We here derive the effective motion on the surface allowing for additional Diffusion on the cylindrical surface itself. We find explicit solutions for the number of adsorbed particles at one given instant, the effective surface displacement, as well as the surface propagator. In particular sub- and superdiffusive regimes are found, as well as an effective stalling of Diffusion visible as a plateau in the mean squared displacement. We also investigate the corresponding first passage problem.
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effective surface motion on a reactive cylinder of particles that perform intermittent Bulk Diffusion
arXiv: Statistical Mechanics, 2011Co-Authors: Aleksei V Chechkin, Irwin M Zaid, Michael A Lomholt, I M Sokolov, Ralf MetzlerAbstract:In many biological and small scale technological applications particles may transiently bind to a cylindrical surface. In between two binding events the particles diffuse in the Bulk, thus producing an effective translation on the cylinder surface. We here derive the effective motion on the surface, allowing for additional Diffusion on the cylinder surface itself. We find explicit solutions for the number of adsorbed particles at one given instant, the effective surface displacement, as well as the surface propagator. In particular sub- and superdiffusive regimes are found, as well as an effective stalling of Diffusion visible as a plateau in the mean squared displacement. We also investigate the corresponding first passage and first return problems.
Emily A Carter - One of the best experts on this subject based on the ideXlab platform.
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quantum mechanics based design principles for solid oxide fuel cell cathode materials
Energy and Environmental Science, 2011Co-Authors: Michele Pavone, Andrew M Ritzmann, Emily A CarterAbstract:Low oxide ion conductivity in perovskite-type transition metal oxides is one of the major problems with solid oxide fuel cells (SOFCs). Here, simple quantum mechanical analyses of LaMO3 (M = Cr, Mn, Fe, Co) materials provide new insights into what drives the relative ease of formation of oxygen vacancies, which is a prerequisite for and predictor of oxide ion Bulk Diffusion. From our results, we derive design principles based on easily measurable or computable properties to improve SOFC cathode materials.
