Nuclear magnetic resonance proton relaxation in bimetallic complexes containing cobalt(II)

1987 ◽  
Vol 109 (17) ◽  
pp. 5208-5212 ◽  
Author(s):  
Ivano Bertini ◽  
Charlotte Owens ◽  
Claudio Luchinat ◽  
Russell S. Drago
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Proton Relaxation ◽  
Bimetallic Complexes ◽  
Nuclear Magnetic

Low temperature nuclear magnetic resonance studies of NH4ClO4

1976 ◽  
Vol 54 (3) ◽  
pp. 239-251 ◽  
Author(s):  
R. F. Code ◽  
J. Higinbotham ◽  
A. R. Sharp
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Low Temperature ◽  
Relaxation Times ◽  
Ammonium Ion ◽  
Proton Relaxation ◽  
Spin Conversion ◽  
Type Symmetry ◽  
Symmetry Species ◽  
Nuclear Magnetic

The properties of ammonium perchlorate were investigated in the temperature range between 1.3 and 50 K by nuclear magnetic resonance and relaxation experiments. The observed increase in the proton second moment from its high temperature value of ~ 1.18 G2 to the value of 4.30 G2 below 4.2 K was associated with a characteristic activation energy of ~ 4 × 10−21 J molecule−1 (~ 0.6 kcal mole−1). No evidence could be found for nuclear spin conversion between the symmetry species of the ammonium ion from measurements of the static proton magnetic susceptibility above 1.3 K. An asymptotic analysis of the low temperature proton lineshapes identified the broad wings of the lines with ammonium ions of T type symmetry. Measurements of the proton relaxation times T1 and T1ρ agreed with previous work by others on NH4ClO4, and were similar to observations on other ammonium compounds having low reorientational barriers.

scholarly journals Water ordering during the cell cycle: nuclear magnetic resonance studies of the sea-urchin egg

1985 ◽  
Vol 79 (1) ◽  
pp. 247-257
Author(s):  
S. Zimmerman ◽  
A.M. Zimmerman ◽  
G.D. Fullerton ◽  
R.F. Luduena ◽  
I.L. Cameron
Keyword(s):  
Cell Cycle ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Low Temperature ◽  
Sea Urchin ◽  
Water Proton ◽  
Proton Relaxation ◽  
Mitotic Apparatus ◽  
Microtubule Protein ◽  
Nuclear Magnetic

Nuclear magnetic resonance was used to measure spin-lattice water proton relaxation times (T1) during the first cell cycle in sea-urchin zygotes of packed Strongylocentrotus purpuratus. Following insemination there was a 90% increase in the T1 value. The increase in T1 at fertilization could be accounted for by the accumulation of extracellular fluid between the egg surface and the fertilization envelope. The T1 value then remained without change during the first cell cycle, except at metaphase when there was a significant 13% decrease. The lowered T1 values measured at metaphase were not related to a change in the water content of the packed cells, which remained fairly constant throughout the cell cycle. High hydrostatic pressure, low temperature and colchicine (agents that depolymerize mitotic apparatus microtubules) did not affect the T1 values in fertilized eggs. Treatment in vitro of a microtubule protein preparation with low temperature and colchicine resulted in an increased T1, which accompanied the depolymerization of microtubule protein. Since depolymerization of the microtubules associated with the mitotic apparatus by high pressure, colchicine or low temperature does not alter the T1 of water protons in the cell, it is proposed that the increased state of ordered water molecules at metaphase is maintained by nonmicrotubular factor(s) of the metaphase egg.

A proton nuclear magnetic resonance relaxation study of the glycine, alanine, and lactate complexes of gadolinium(III) in aqueous solution

1987 ◽  
Vol 65 (7) ◽  
pp. 1508-1512 ◽  
Author(s):  
R. Stephen Reid ◽  
Benjamin Podányi
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Membered Ring ◽  
Proton Nuclear Magnetic Resonance ◽  
Proton Relaxation ◽  
Carboxylate Group ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Resonance Spin ◽  
Nuclear Magnetic

The 1H nuclear magnetic resonance spin-lattice and spin–spin relaxation rate enhancements induced by the gadolinium(III) ion were measured in solutions of glycine, alanine, and sodium lactate containing different amounts of Gd(III). The proton relaxation rates in the Gd(III) complexes were calculated from these data, and were used to calculate metal–hydrogen atom distances. Comparison of these data with corresponding distances calculated from literature X-ray crystallographic data for model compounds shows that in the two amino acid complexes the Gd(III) ion is coordinated in a four-membered ring through the two oxygen atoms of the carboxylate group. By contrast, in the lactate complex coordination is via a five-membered ring involving one oxygen atom of the carboxylate group and the α-hydroxyl oxygen.

scholarly journals Single-sided Time Domain-Nuclear Magnetic Resonance to Study the Effect of Cell Membrane Electroporation on the Water Mobility in Vegetal Tissues

2021 ◽  
Vol 11 (6) ◽  
pp. 14127-14141
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Time Domain ◽  
Peak Position ◽  
Molecular Water ◽  
Proton Relaxation ◽  
Water Mobility ◽  
Potato Tubers ◽  
Microscopic Morphology ◽  
Nuclear Magnetic

This paper presents the characteristics of potato and apple tissues, with/out electroporation, by Time Domain-Nuclear Magnetic Resonance (TD-NMR). A portable TD-NMR was used to measure the proton relaxation time, T2, and the changes in the cells due to molecular water mobility of potato tubers,-NMR to identify the modifications that occurred at the cell level involving water molecules mobility in potato tubers and apple tissues after the electroporation treatment and compared with non-electroporated ones. The comparisons with normal potato and apple tissue and preliminary measurements in bulk were performed. Samples were also analyzed in terms of conductivity of the tissue and microscopic morphology. The results indicate that the electroporation process effect is identified with a variation of the peak position in T2 distribution, associated with sub-cell modifications.

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