Wave velocity and diffusion constant in strongly scattering media

1993 ◽  
Vol 73 (7) ◽  
pp. 3133-3138 ◽  
Author(s):  
L. A. Ferrari ◽  
Al‐Karim Gangji
Keyword(s):  
Wave Velocity ◽  
Diffusion Constant ◽  
Scattering Media ◽  
And Diffusion

scholarly journals Water and Deuterium Oxide Permeability through Aquaporin 1: MD Predictions and Experimental Verification

2007 ◽  
Vol 130 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Artem B. Mamonov ◽  
Rob D. Coalson ◽  
Mark L. Zeidel ◽  
John C. Mathai
Keyword(s):  
Deuterium Oxide ◽  
Diffusion Constant ◽  
Structural Data ◽  
Md Simulations ◽  
Water Model ◽  
Aquaporin 1 ◽  
Self Diffusion ◽  
Osmotic Permeability ◽  
Protein Channels ◽  
And Diffusion

Determining the mechanisms of flux through protein channels requires a combination of structural data, permeability measurement, and molecular dynamics (MD) simulations. To further clarify the mechanism of flux through aquaporin 1 (AQP1), osmotic pf (cm3/s/pore) and diffusion pd (cm3/s/pore) permeability coefficients per pore of H2O and D2O in AQP1 were calculated using MD simulations. We then compared the simulation results with experimental measurements of the osmotic AQP1 permeabilities of H2O and D2O. In this manner we evaluated the ability of MD simulations to predict actual flux results. For the MD simulations, the force field parameters of the D2O model were reparameterized from the TIP3P water model to reproduce the experimentally observed difference in the bulk self diffusion constants of H2O vs. D2O. Two MD systems (one for each solvent) were constructed, each containing explicit palmitoyl-oleoyl-phosphatidyl-ethanolamine (POPE) phospholipid molecules, solvent, and AQP1. It was found that the calculated value of pf for D2O is ∼15% smaller than for H2O. Bovine AQP1 was reconstituted into palmitoyl-oleoyl-phosphatidylcholine (POPC) liposomes, and it was found that the measured macroscopic osmotic permeability coefficient Pf (cm/s) of D2O is ∼21% lower than for H2O. The combined computational and experimental results suggest that deuterium oxide permeability through AQP1 is similar to that of water. The slightly lower observed osmotic permeability of D2O compared to H2O in AQP1 is most likely due to the lower self diffusion constant of D2O.

Diffusion Constant and Diffusion Coefficient

Science ◽  
1955 ◽  
Vol 121 (3137) ◽  
pp. 215-216 ◽  
Author(s):  
J. VERDUIN
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Constant ◽  
And Diffusion

Spin relaxation due to magnetic-field inhomogeneities: Quartic dependence and diffusion-constant measurements

1990 ◽  
Vol 41 (7) ◽  
pp. 3672-3688 ◽  
Author(s):  
K. C. Hasson ◽  
G. D. Cates ◽  
K. Lerman ◽  
P. Bogorad ◽  
W. Happer
Keyword(s):  
Magnetic Field ◽  
Spin Relaxation ◽  
Diffusion Constant ◽  
And Diffusion

Monte Carlo and diffusion calculations of photon migration in noninfinite highly scattering media

1991 ◽  
Author(s):  
John C. Haselgrove ◽  
John S. Leigh, Jr. ◽  
Conway Yee ◽  
NaiGuang Wang ◽  
Michael B. Maris ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Photon Migration ◽  
Scattering Media ◽  
And Diffusion

Long-Range Diffusion of Hydrogen in Solid-Solution PdCe Alloys as Deduced from Absorption Experiments

2008 ◽  
Vol 273-276 ◽  
pp. 381-387 ◽  
Author(s):  
Giovanni Mazzolai
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Thermal Decomposition ◽  
Diffusion Coefficient ◽  
High Temperature ◽  
Diffusion Constant ◽  
Absorption Data ◽  
Friction Measurements ◽  
And Diffusion ◽  
Diffusion Of Hydrogen

The diffusion of H and the thermal decomposition of hydrides have been investigated at high temperatures in two PdCe alloys of composition 5% and 9% Ce. It has been found that the H diffusion coefficient obeys an Arrhenius-type of law with the following values of the activation energy W and diffusion constant D0, ( )     = ± × = ± − s m D W eV 2 7 0 2 2 10 0.20 0.02 (Pd95Ce5 alloy) ( )     = ± × = ± − s m D W eV 2 7 0 2 1 10 0.24 0.01 (Pd91Ce9 alloy) The high-temperature absorption data match the low-temperature ones deduced from internal friction measurements, indicating that Ce atoms do not act as strong trapping centres for H. Thermal decomposition of hydrides in the Pd95Ce5H0.008 alloy occurs in a single stage showing a homogeneous solid solution state of the H-Me system.

Diffusion Constant and Diffusion Coefficient

Science ◽  
1955 ◽  
Vol 121 (3137) ◽  
pp. 215-216
Author(s):  
Jacob Verduin
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Constant ◽  
And Diffusion
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