Monitoring of cell volume and water exchange time in perfused cells by diffusion-weighted1H NMR spectroscopy

1998 ◽  
Vol 11 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Josef Pfeuffer ◽  
Ulrich Flögel ◽  
Dieter Leibfritz
Keyword(s):  
Nmr Spectroscopy ◽  
Cell Volume ◽  
Water Exchange ◽  
Exchange Time ◽  
Water Exchange Time

The diffusional water permeability of Elodea leaf cells as measured by nuclear magnetic resonance

1977 ◽  
Vol 55 (12) ◽  
pp. 1623-1631 ◽  
Author(s):  
Darryl G. Stout ◽  
Robert M. Cotts ◽  
Peter L. Steponkus
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Permeability ◽  
Water Exchange ◽  
Transverse Relaxation Time ◽  
Exchange Time ◽  
Unstirred Layers ◽  
Water Permeability Coefficient ◽  
Water Exchange Time ◽  
Nuclear Magnetic

A new nuclear magnetic resonance (NMR) technique developed by Conlon and Outhred (1972. Biochim. Biophys. Acta, 288: 354–361) to measure diffusional water permeability was applied to the multicellular plant system Elodea Nuttallii (Planch) St. John leaves. This technique involves measuring a transverse relaxation time (T2) in the absence (T2 = Ta) and in the presence (T2 = Ta′) of extracellular paramagnetic cations. A valid estimate of Ta was measured for Elodea leaves. The value of Ta′ was found to decrease continuously with time. Evidence is presented that the decrease of Ta′ with time is initially related primarily to the time required for the paramagnetic ion to diffuse throughout the extracellular space and then later related to influx of the paramagnetic ion into the cells. By extrapolating to zero time to correct for paramagnetic-cation influx into the cells it was possible to estimate the value of Ta′ required to calculate the water exchange time out of the cells. It was estimated from the NMR data that Mn2+ (the paramagnetic ion used) flux into the cells occurred at a rate of 3.0 × 10−14 mol cm2 s−1. A procedure to determine whether the water-exchange time is controlled by intracellular unstirred layers or by membrane water permeability or by both is given. The water-exchange time of Elodea leaves is predominantly controlled by the intracellular unstirred layers. Thus it was only possible to set a lower limit on the diffusional water permeability coefficient (Pd) of Elodea leaf membranes of 3 × 10−2 cm s−1 at 20 °C.

Long-Distance Water Exchange within Dense Clay Sediments Probed by Two-Time 2H Stimulated Echo NMR Spectroscopy

2013 ◽  
Vol 117 (19) ◽  
pp. 9920-9931 ◽  
Author(s):  
Patrice Porion ◽  
Anne Marie Faugère ◽  
Alfred Delville
Keyword(s):  
Nmr Spectroscopy ◽  
Water Exchange ◽  
Long Distance ◽  
Stimulated Echo

Rates of Water Exchange in 2,2′-Bipyridine and 1,10-Phenanthroline Complexes of CoII and MnII

2017 ◽  
Vol 70 (6) ◽  
pp. 751 ◽  
Author(s):  
Shravan S. Acharya ◽  
Bjorn Winther-Jensen ◽  
Leone Spiccia ◽  
C. André Ohlin
Keyword(s):  
Nmr Spectroscopy ◽  
Water Exchange ◽  
Variable Temperature ◽  
Activation Parameters ◽  
Cobalt Complexes ◽  
Degree Of Substitution ◽  
Manganese Complexes ◽  
17O Nmr ◽  
17O Nmr Spectroscopy

The rates and activation parameters of water exchange at pH 3.0 have been determined using variable temperature 17O NMR spectroscopy for four CoII complexes and one MnII complex: [Co(bpy)(H2O)4]2+, [Co(bpy)2 (H2O)2]2+, [Co(phen)-(H2O)4]2+, [Co(phen)2 (H2O)2]2+, and [Mn(bpy)(H2O)4]2+ (bpy = 2,2′-bipyridyl and phen = 1,10-phenanthroline). Substitution of aquo ligands with 1,10-phenanthroline or 2,2′-bipyridyl leads to an increase in the rate of exchange in the manganese complexes, from k298 (1.8 ± 0.1) × 107 s−1 for [Mn(H2O)6]2+ to (7.2 ± 0.3) × 107 s−1 for [Mn(phen)2 (H2O)2]2+, whereas the trends are more complex for the cobalt complexes. We have used the new data in conjunction with literature data for similar complexes to analyse the effect of M–OH2 distance and degree of substitution.

scholarly journals DEVELOPMENT OF SYSTEM FOR AUTOMATION OF PROCESS OF DESIGNING OF WATER TREATMENT SYSTEMS FOR SWIMMING POOLS

2019 ◽  
Vol 2019 (2) ◽  
pp. 33-42
Author(s):  
Сергей Игнатьев ◽  
Sergey Ignatiev ◽  
Андрей Аверченков ◽  
Andrey Averchenkov
Keyword(s):  
Water Treatment ◽  
Water Exchange ◽  
3D Model ◽  
3D Models ◽  
Treatment System ◽  
Swimming Pools ◽  
Water Treatment System ◽  
Design Time ◽  
Water Exchange Time ◽  
Selection Of

This article discusses and solves the problem of designing swimming pools. Previously, before the advent of modern CAD, designers had to manually draw drawings, as any automation was not available, and it took too much time and effort, and the percentage of errors and errors was large enough. With the advent of modern CAD, the design of objects has become much easier, it is enough to build a 3D model, and drawings and specifications will be formed automatically. And when you make any change to the 3D model, the drawings and specifications are updated automatically. This greatly simplifies and speeds up the design. But not everything is still automated. When designing swimming pools, each new project begins with the selection of equipment for water treatment of a particular pool. Selection of equipment depends on the set of initial data determined by the customer, such as: the type and size of the pool, water exchange time, the desired temperature in the pool and so on. Based on these data, the equipment for the water treatment system is calculated (all calculations are strictly regulated according to GOST). Further, after the selection of equipment, a geometric 3D model of the pool is built. The geometric 3D model of the entire water treatment system is designed in stages: a pool bowl is designed, a technical room is designed, 3D models of previously calculated equipment are installed and everything is tied with a pipeline. Since it takes a lot of time to calculate the equipment and design the pool bowl, and with each new project it has to be done "from scratch", it was decided to automate these modules. The article presents the development of a program to automate the calculation of equipment and the construction of a geometric 3D model of the pool bowl. This development is implemented in the company "ASTRAL CIS", engaged in the design of swimming pools and is actively used, reducing the design time by 2 working days.

Rates and Mechanism of Fluoride and Water Exchange in UO2F53-and [UO2F4(H2O)]2-Studied by NMR Spectroscopy and Wave Function Based Methods

2002 ◽  
Vol 41 (21) ◽  
pp. 5626-5633 ◽  
Author(s):  
Valérie Vallet ◽  
Ulf Wahlgren ◽  
Zoltán Szabó ◽  
Ingmar Grenthe
Keyword(s):  
Wave Function ◽  
Nmr Spectroscopy ◽  
Water Exchange
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