Diffusion coefficient of water in water and in some alkaline earth chloride solutions at 25°C

Jones, Jimmy; Rowlands, D.L.G.; Monk, C. B.

doi:10.1039/tf9656101384

Cited by 29 publications

(14 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Specifically, for each of the 4 different water-fat distributions analyzed (Figure 1), each consisting of a 128×128×128 matrix with an isotropic pixel size of 2.056 μm, we tracked the evolution of 25,000 spins for a total time of 2 s. During this time, each spin was allowed to evolve under the local magnetic field for a total time of 0.167 ms before diffusing to a different position. Diffusion was computed with a random walk Monte Carlo algorithm using a diffusion length L of 1.5 μm, calculated by using:

L = \sqrt{6 \cdot D \cdot τ},

with D being 2.22×10 −3 mm 2 ·s −1 (37) and τ=0.167 ms. A Fourier transform of the simulated FID was then performed to obtain a spectrum from which water and fat frequency shifts were determined.…”

Section: Methodsmentioning

confidence: 99%

Accurate MR thermometry by hyperpolarized ¹²⁹Xe

Zhang

Burant

McCallister

et al. 2016

Magnetic Resonance in Med

View full text Add to dashboard Cite

Purpose To investigate the temperature dependence of the resonance frequency of Lipid-Dissolved Xenon (LDX) and to assess the accuracy of LDX-based MR thermometry. Methods The chemical shift temperature dependence of water protons, methylene protons, and LDX was measured from samples containing tissues with varying fat contents using a high-resolution NMR spectrometer. LDX results were then used to acquire relative and absolute temperature maps in vivo and the results were compared to PRF-based MR thermometry. Results The temperature dependence of PRF is strongly affected by the specific distribution of water and fat. A redistribution of water and fat compartments can reduce the apparent temperature dependence of the water chemical shift from −0.01ppm/°C to −0.006ppm, whereas the LDX chemical shift shows a consistent temperature dependence of −0.21ppm/°C. The use of the methylene protons resonance frequency as internal reference improves the accuracy of LDX-based MR thermometry but degrades that of PRF-based MR thermometry as microscopic susceptibility gradients affected lipid and water spins differently. Conclusion The LDX resonance frequency, with its higher temperature dependence, provides more accurate and precise temperature measurements, both in vitro and in vivo. More importantly, the resonance frequency of nearby methylene protons can be used to extract absolute temperature information.

show abstract

L = \sqrt{6 \cdot D \cdot τ},

Section: Methodsmentioning

confidence: 99%

Accurate MR thermometry by hyperpolarized ¹²⁹Xe

Zhang

Burant

McCallister

et al. 2016

Magnetic Resonance in Med

View full text Add to dashboard Cite

show abstract

“…The ratio for diffusion coefficients D(lo)1/D(K+), based on the rates of unhindered diffusion in aqueous solutions, shows that water diffuses 1.2 times faster than K+. Values of DR2o and DK+ were taken from Harned and Owen (4) and Jones et al (8), respectively. The difference between these relative rates indicates that at pH below 6 the observed differences between cuticular penetration of H20 and of K+ are not explainable by differences in diffusion rates alone.…”

Section: Methodsmentioning

confidence: 99%

Cation Penetration through Isolated Leaf Cuticles

McFarlane¹,

Berry

1974

Plant Physiol.

View full text Add to dashboard Cite

The rates of penetration of various cations through isolated apricot Prunus armeniaca L. leaf cuticles were determined.Steady state rates were measured by using a specially constructed flow-through diffusion cell. The penetration rates of the monovalent cations in group IA followed a normal lyotropic series, i.e., CS+ > Rb+ > K+ > Na+ > Li+. The Leaf cuticle has a major influence on the absorption and ultimate impact of foliarly applied materials. Not only do pesticides, nutrients, and growth regulators enter plants through their leaves, but many pollutants also enter plants via this route. Foliar absorption may therefore either increase or decrease plant yield depending on conditions. The monographs of Hull (7) and Martin and Juniper (10) are especially valuable in bringing together and analyzing the many reports about cuticles and absorption. Both reviews reveal apparent gaps in our knowledge of the mechanisms and kinetics of cuticular penetration. Schumacher and Lambertz (17) described structures in the outer cell wall of leaf epidermal cells, and they and others assigned to them an important role in transcuticular penetration. These structures, which were observed adjacent to the cuticle, were later called ectodesmata and have been the focus of much attention. Recently, Schbnherr and Bukovac (16) showed that ectodesmata appear only at sites of penetration in the cuticle and, in fact, demonstrated similar structures in agar resulting from the penetration of material through an isolated cuticle. Thus, the appearance of ectodesmata was It was the purpose of this research to determine the rates and mechanism of cation penetration through isolated cuticles. In order to ascertain whether or not simple unhindered diffusion satisfactorily explains cuticular penetration, penetration rates were compared to those of simple unhindered diffusion in aqueous solutions. The effects of concentration and pH were also investigated in order to obtain data pertinent to the mechanism involved. Kinetic data from this research reveal some interesting characteristics about cuticular pores. MATERIALS AND METHODSCuticles were separated from the upper (nonstomatous) surface of apricot leaves (Prunus armeniaca L.) using the method described by Holloway and Baker (5). In brief, it consisted of selecting large leaves and punching two discs, 3 cm in diameter from each side of the midrib. The leaf discs were floated on a solution of ZnCl, in concentrated HCl (1 g in 1.7 ml) with the top surface up. The acid solution was infused into the leaf by vacuum infiltration. After 3 hr the cuticle was stripped, washed, and floated onto distilled water for storage in the refrigerator at 4 C until used.A diffusion cell was constructed by making a master in brass and casting a die with silicone rubber (General Electric . From the die, half-cells were cast using Ferris No. See-Thru flexible mold compound. The resulting half-cells were clear semihard rubber. The surfaces adhered to each other so that no grease was needed to seal the system. S...

show abstract

“…The local concentration of the reactant was the main result followed in the simulations and is governed by Fick’s law, which is described by the diffusion and convection equation:

\nabla \cdot (- D \nabla c) + u \cdot \nabla c = R

where D is the diffusion coefficient of the reactant, c is the concentration of the reactant, and R is the consumption rate of the reactant. Simulations were carried out using the diffusion coefficient of water molecules, D = 2.2 × 10 −9 m 2 /s, 34 for direct comparison with the H 2 O/D 2 O mixing experiments. Other parameters used in simulation can be found in the Supplementary Information.…”

Section: Methodsmentioning

confidence: 99%

Submillisecond mixing in a continuous-flow, microfluidic mixer utilizing mid-infrared hyperspectral imaging detection

et al. 2014

View full text Add to dashboard Cite

We report a continuous-flow, microfluidic mixer utilizing mid-infrared hyperspectral imaging detection, with an experimentally determined, submillisecond mixing time. The simple and robust mixer design has the microfluidic channels cut through a polymer spacer that is sandwiched between two IR transparent windows. The mixer hydrodynamically focuses the sample stream with two side flow channels, squeezing it into a thin jet and initiating mixing through diffusion and advection. The detection system generates a mid-infrared hyperspectral absorbance image of the microfluidic sample stream. Calibration of the hyperspectral image yields the mid-IR absorbance spectrum of the sample versus time. A mixing time of 269 μs was measured for a pD jump from 3.2 to above 4.5 in a D2O sample solution of adenosine monophosphate (AMP), which acts as an infrared pD indicator. The mixer was further characterized by comparing experimental results with a simulation of the mixing of an H2O sample stream with a D2O sheath flow, showing good agreement between the two. The IR microfluidic mixer eliminates the need for fluorescence labeling of proteins with bulky, interfering dyes, because it uses the intrinsic IR absorbance of the molecules of interest, and the structural specificity of IR spectroscopy to follow specific chemical changes such as the protonation state of AMP.

show abstract

Diffusion coefficient of water in water and in some alkaline earth chloride solutions at 25°C

Cited by 29 publications

References 2 publications

Accurate MR thermometry by hyperpolarized ¹²⁹Xe

Accurate MR thermometry by hyperpolarized ¹²⁹Xe

Cation Penetration through Isolated Leaf Cuticles

Submillisecond mixing in a continuous-flow, microfluidic mixer utilizing mid-infrared hyperspectral imaging detection

Contact Info

Product

Resources

About

Diffusion coefficient of water in water and in some alkaline earth chloride solutions at 25°C

Cited by 29 publications

References 2 publications

Accurate MR thermometry by hyperpolarized 129Xe

Accurate MR thermometry by hyperpolarized 129Xe

Cation Penetration through Isolated Leaf Cuticles

Submillisecond mixing in a continuous-flow, microfluidic mixer utilizing mid-infrared hyperspectral imaging detection

Contact Info

Product

Resources

About

Accurate MR thermometry by hyperpolarized ¹²⁹Xe

Accurate MR thermometry by hyperpolarized ¹²⁹Xe