The drift self-diffusion of water molecules

1974 ◽  
Vol 14 (6) ◽  
pp. 1032-1033 ◽  
Author(s):  
N. P. Malomuzh ◽  
I. Z. Fisher
Keyword(s):  
Water Molecules ◽  
Self Diffusion

c , T-Dependence of the Self Diffusion in Concentrated Aqueous Sucrose Solutions

1994 ◽  
Vol 49 (3-4) ◽  
pp. 258-264 ◽  
Author(s):  
D. Girlich ◽  
H.-D. Lüdemann ◽  
C. Buttersack ◽  
K. Buchholz
Keyword(s):  
Field Gradient ◽  
Concentration Dependence ◽  
Diffusion Coefficients ◽  
The Self ◽  
Water Molecules ◽  
Pulsed Field Gradient Nmr ◽  
Pulsed Field ◽  
Self Diffusion ◽  
Sucrose Solutions ◽  
Wide Range

The self diffusion coefficients D of the water molecules and of sucrose have been determined by the pulsed field gradient NMR technique over a wide range of temperatures and concentrations (cmax: 70% w/w suc.). All temperature dependencies can be fitted to a Vogel- Tammann-Fulcher equation. The isothermic concentration dependence of D for the sucrose is given by a simple exponential concentration dependence

scholarly journals Proton Magnetic Resonance Studies of Water in Slime Mould Plasmodia

1971 ◽  
Vol 24 (3) ◽  
pp. 497 ◽  
Author(s):  
JA Walter ◽  
AB Hope
Keyword(s):  
Relaxation Times ◽  
Bulk Water ◽  
Proton Spin ◽  
Water Molecules ◽  
Signal Pulse ◽  
Cellular Functions ◽  
Slime Mould ◽  
Self Diffusion ◽  
Spin Lattice ◽  
Cytoplasmic Structures

Steady-state and pulse n.m.r. techniques have been applied in a study of water in the cytoplasm of slime mould plasmodia (Ph;ysarum polycephalum). The former method has been used to confirm that the signal detected was from protons in water molecules, and to estimate the fraction of the total water in the sample that was contributing to the observed signal. Pulse techniques have enabled direct measurement of the self-diffusion coefficient D of the bulk water in the cytoplasm, and the proton spin-lattice and spin-spin relaxation times Tl and T2 respectively. The measurements of D can be accounted for if most of the water is in a "free" state, similar to water in a dilute ionic solution, but with a lower value of D due to the obstruction effect of macromolecules and cytoplasmic structures. The values of Tl and T2 indicate that a small "bound" fraction of the water molecules has more restricted motion. The assumption of a two-state model, with exchange of water molecules between "free" and "bound" phases in a time ~ 10-3 sec, yields a representative correlation time T "'" 10-8 sec for the bound fraction. This model is the simplest compatible with all the above results. The underlying assumptions, the extent to which it is likely to be an approximation, and the implications regarding some theories of cellular functions are discussed. Similar results have also been obtained from samples of toad leg muscle, ceils from the meristematic region of pea roots, and from agar and gelatin gels.

Kinetics of self-diffusion of water molecules in natrolite

2016 ◽  
Vol 57 (2) ◽  
pp. 325-329
Author(s):  
A. V. Sabylinskii ◽  
N. K. Moroz ◽  
S. P. Gabuda
Keyword(s):  
Water Molecules ◽  
Self Diffusion ◽  
Kinetics Of

Molecular Dynamics Study of a KCl Aqueous Solution: Dynamical Results

1987 ◽  
Vol 42 (3) ◽  
pp. 227-230 ◽  
Author(s):  
M. Migliore ◽  
S. L. Fornili ◽  
E. Spohr ◽  
K. Heinzinger
Keyword(s):  
Diffusion Coefficients ◽  
Md Simulation ◽  
Bulk Water ◽  
Water Molecules ◽  
Hydration Water ◽  
Self Diffusion ◽  
Average Temperature ◽  
Velocity Autocorrelation ◽  
Dynamical Properties ◽  
Velocity Autocorrelation Functions

In this paper we report on dynamical properties of a 2.2 molal aqueous KCl solution as obtained from an 8.7 ps MD simulation at an average temperature of 289 K. Velocity autocorrelation functions, self-diffusion coefficients and spectral densities of the hindered translational and librational motions of the ions and the water molecules assigned to three subsystems - hydration water of the cations, hydration water of the anions and bulk water - are discussed.

scholarly journals Anesthetic Gases and Water Structure

1968 ◽  
Vol 52 (6) ◽  
pp. 876-886 ◽  
Author(s):  
Eugene Y. Berger ◽  
F. Rene Pecikyan ◽  
Grace Kanzaki
Keyword(s):  
Tritiated Water ◽  
Water Flux ◽  
Water Structure ◽  
Water Molecules ◽  
Crystal Formation ◽  
Self Diffusion ◽  
Average Water ◽  
Anesthetic Gases ◽  
Hydrate Crystal ◽  
Hydrogen Bonded

Pauling and Miller have independently proposed that the presence of an anesthetic gas in tissue induces a cage-like arrangement of hydrogen-bonded water molecules. The theories recognize that most gas-hydrate crystals would not form at the temperature and pressure that exist during anesthesia and propose that other components of tissue such as protein should have a stabilizing effect. Measurements of the behavior of water, rather than the anesthetic agent, would provide alternative information about the likelihood of hydrate crystal formation and this information could be such as to be applicable to body temperature and to pressures used for anesthesia. If the number of hydrogen-bonded water molecules in tissue is increased, then the movement of an average water molecule should be hindered. Movement of water through the tissue may be measured by tagging it with tritium and the anesthetic gas should then slow the movement of tritiated water through the tissue. The flux of tritiated water through rat cecum is indeed slowed when the cecum is exposed to the anesthetic gas, xenon, which can participate biochemically only by virtue of its van der Waals interaction. The decrement in water flux is in reasonable agreement with what could be expected theoretically from calculations based on the activation energy for the self-diffusion of water and the degree of hypothermia necessary to produce narcosis.

scholarly journals Nano-metering of Solvated Biomolecules Or Nanoparticles from Water Self-Diffusivity in Bio-inspired Nanopores

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Luca Bergamasco ◽  
Matteo Alberghini ◽  
Matteo Fasano
Keyword(s):  
Diffusion Coefficient ◽  
Liquid System ◽  
The Self ◽  
Water Molecules ◽  
Indirect Measure ◽  
Self Diffusion ◽  
Pore Liquid ◽  
Time Required ◽  
Practical Feasibility ◽  
Self Diffusion Coefficient

Abstract Taking inspiration from the structure of diatom algae frustules and motivated by the need for new detecting strategies for emerging nanopollutants in water, we analyze the potential of nanoporous silica tablets as metering devices for the concentration of biomolecules or nanoparticles in water. The concept relies on the different diffusion behavior that water molecules exhibit in bulk and nanoconfined conditions, e.g., in nanopores. In this latter situation, the self-diffusion coefficient of water reduces according to the geometry and surface properties of the pore and to the concentration of suspended biomolecules or nanoparticles in the pore, as extensively demonstrated in a previous study. Thus, for a given pore-liquid system, the self-diffusivity of water in nanopores filled with biomolecules or nanoparticles provides an indirect measure of their concentration. Using molecular dynamics and previous results from the literature, we demonstrate the correlation between the self-diffusion coefficient of water in silica nanopores and the concentration of proteins or nanoparticles contained therein. Finally, we estimate the time required for the nanoparticles to fill the nanopores, in order to assess the practical feasibility of the overall nano-metering protocol. Results show that the proposed approach may represent an alternative method for assessing the concentration of some classes of nanopollutants or biomolecules in water.

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