The Role of the Cathode Diffusion Layer in the Electrodeposition of Alloys

A theoretical analysis of the initial rates of product appearance in both compartments of a specifically designed diffusion cell separated by an asymmetrical enzyme membrane is presented. Variable substrate concentrations and different substrate diffusional limitations were considered. Our analysis shows that, under specific conditions, not only a product accumulation occurs in the compartment opposite to that in which the reaction takes place, but that substrate saturable kinetics can be obtained. These product translocation-like kinetics appear similar to those observed with translocation processes reported for biological situations. For such phenomena, a key role of the diffusion layer surrounding a bioactive surface is proposed.

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The Role of Gas Diffusion Layer in Cationic Contamination and Mitigation in Polymer Electrolyte Fuel Cells

ECS Transactions ◽

10.1149/06403.0537ecst ◽

2014 ◽

Vol 64 (3) ◽

pp. 537-544 ◽

Cited By ~ 2

Author(s):

M. A. Uddin ◽

J. Park ◽

X. Wang ◽

J. Qi ◽

U. Pasaogullari ◽

...

Keyword(s):

Fuel Cells ◽

Polymer Electrolyte ◽

Diffusion Layer ◽

Gas Diffusion Layer ◽

Gas Diffusion ◽

Polymer Electrolyte Fuel Cells ◽

Cationic Contamination

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Compartmentalized system with membrane-bound glycerol kinase. Activity and product distribution versus asymmetrical substrate supply

Biochemical Journal ◽

10.1042/bj2740819 ◽

1991 ◽

Vol 274 (3) ◽

pp. 819-824 ◽

Cited By ~ 9

Author(s):

A Girard ◽

B Merchie ◽

B Maïsterrena

Keyword(s):

Enzyme Activity ◽

Diffusion Layer ◽

Cumulative Effect ◽

Product Distribution ◽

Substrate Supply ◽

Enzyme Model ◽

Membrane Bound ◽

The Asymmetry

An artificial-membrane-bound glycerokinase chosen as a membrane-bound two-substrate-enzyme model has been used to separate two unequal compartments of a specially designed diffusion cell. An interesting feature is the asymmetry of compartments and the existence of a diffusion layer adjacent to only one face of the enzymic membrane. In such a situation the apparent enzyme activity and the product distribution in the system have been studied versus all the possibilities of combination of ATP and glycerol supply. Our approach has lead us to differentiate two different roles played by a diffusion layer adjacent to a permeable enzymic membrane. Depending on the spatial origin of the enzymic substrates (i.e. from which compartment they derive), the diffusion layer can play either the role of a passive additional resistance to that of the membrane or the role of a third compartment in which the reaction product can partially accumulate before splitting on both parts of the membrane. Our results mainly demonstrate that a membrane-bound enzyme activity and the resulting product distribution occurring in a compartmentalized system may be regulated by the cumulative effect due to the asymmetry in volumes of the compartments, the presence of a diffusion layer and the different possibilities of substrate supply. With the topography studied, which is close to that reported for many ‘in vivo’ situations, the product may be diffused lead to vectorial metabolism processes.

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