The lipid bilayer is crucial for the folding of integral membrane proteins. This article presents an empirical method to account for water-lipid interfaces in the insertion of molecules interacting with bilayers. The ...
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The lipid bilayer is crucial for the folding of integral membrane proteins. This article presents an empirical method to account for water-lipid interfaces in the insertion of molecules interacting with bilayers. The interactions between the molecule and the bilayer are described by restraint functions designed to mimic the membrane effect. These functions are calculated for each atom and are proportional to the accessible surface of the latter. The membrane is described as a continuous medium whose properties are varying along the axis perpendicular to the bilayer plane. The insertion is analyzed by a Monte Carlo procedure applied to the restraint functions. The method was successfully applied to small ex peptides of known configurations. It provides insights of the behaviors of the peptide dynamics that cannot be obtained with statistical approaches (e.g., hydropathy analysis). (C) 1998 Wiley-Liss, Inc.
Geology and hydrogeology of area;effect of groundwater on working and associated theoretical considerations;pumping tests;dewatering by borehole pumping;scheme and estimated cost for Durham coal field dewatering plant.
Geology and hydrogeology of area;effect of groundwater on working and associated theoretical considerations;pumping tests;dewatering by borehole pumping;scheme and estimated cost for Durham coal field dewatering plant.
High-temperature corrosion is generally known as a material degradation process that occurs at the surface of engineering components. In the case of internal corrosion, the corrosive species penetrates into the materi...
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High-temperature corrosion is generally known as a material degradation process that occurs at the surface of engineering components. In the case of internal corrosion, the corrosive species penetrates into the material by solid-state diffusion leading to the formation of internal precipitates, for instance, oxides (internal oxidation), nitrides (internal nitridation), and carbides (carburization). It is known from numerous publications and technical failure cases that internal corrosion results in a strong deterioration of the properties of a material (i.e., near-surface embrittlement or the dissolution of strengthening phases). The present article introduces the classic theory of internal oxidation and reviews some recent research on internal corrosion phenomena that are closely related to the failure mechanisms of thermally grown protective oxide scales on several commercial high-temperature alloys (e.g., single-crystalline and polycrystalline Ni-base alloys and Cr steels). The mechanisms and kinetics of internal corrosion processes are determined by the temperature, the local chemical composition of the material, the solubility and diffusivity of the corrosive species, as well as the mechanical loading conditions. These influence factors are taken into account by means of a computer model combining a numerical finite-difference approach to solve the diffusion differential equations with the thermodynamic tool ChemApp. Using several examples, it is shown that the model has been applied successfully to simulate the internal nitridation, carburization, and oxidation of high-temperature alloys.
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