Proton NMR Relaxation Effects. Cross‐Relaxation Processes in Pure Liquids

1968 ◽  
Vol 49 (4) ◽  
pp. 1571-1576 ◽  
Author(s):  
A. A. Brooks ◽  
J. D. Cutnell ◽  
E. O. Stejskal ◽  
V. W. Weiss
Keyword(s):  
Proton Nmr ◽  
Nmr Relaxation ◽  
Cross Relaxation ◽  
Relaxation Processes ◽  
Relaxation Effects

Structure and Dynamics of Spherical and Rodlike Alkyl Ethoxylate Surfactant Micelles Investigated Using NMR Relaxation and Atomistic Molecular Dynamics Simulations

2019 ◽  
Author(s):  
Allison Edwards ◽  
Abdolreza Javidialesaadi ◽  
Katie Weigandt ◽  
George Stan ◽  
Charles Eads
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Nmr Relaxation ◽  
Cross Relaxation ◽  
Relaxation Rates ◽  
Surfactant Micelles ◽  
Cylindrical Micelles ◽  
Spherical Micelles ◽  
Dynamics Simulations ◽  
Relative Motions

We study molecular arrangements and dynamics in alkyl ethoxylate nonionic surfactant micelles by combining high field (600 and 700 MHz) NMR relaxation measurements with large-scale atomistic molecular dynamics simulations. For spherical micelles, but not for cylindrical micelles, cross relaxation rates are positive only for surfactant alkyl tail atoms connected to the hydrophilic head group. All cross relaxation rates are negative for cylindrical micelles. This effect is reproducible either by changing composition (ratios of the nonionic surfactants) or changing temperature of a single surfactant in order to change the micelle shape. We validate the micelle shape by SANS and use the results as a guide for our simulations. We calculate parameters that determine relaxation rates directly from simulated trajectories, without introducing specific functional forms. Results indicate that relative motions of nearby atoms are liquid-like, in agreement with 13C T1 measurements, though constrained by micelle morphology. Relative motions of distant atoms have slower components because the relative changes in distances and angles are smaller when the moving atoms are further apart. The slow, long-range motions appear to be responsible for the predominantly negative cross relaxation rates observed in NOESY spectra. The densities of atoms from positions 1 and 2 in the boundary region are lower in spherical micelles compared to cylindrical micelles. Correspondingly, motions in this region are less constrained by micelle morphology in the spherical compared to the cylindrical cases. The two effects of morphology lead to the unusual occurrence of positive cross relaxation involving positions 1 and 2 for spheres.

A proton NMR relaxation evaluation of a model of brain oedema fluid

1986 ◽  
Vol 31 (7) ◽  
pp. 699-711 ◽  
Author(s):  
P S Allen ◽  
M E Castro ◽  
E O Treiber ◽  
J A Lunt ◽  
D P J Boisvert
Keyword(s):  
Brain Oedema ◽  
Proton Nmr ◽  
Nmr Relaxation ◽  
Oedema Fluid

scholarly journals Proton NMR relaxation times in ischemic brain edema.

Stroke ◽  
1986 ◽  
Vol 17 (6) ◽  
pp. 1149-1152 ◽  
Author(s):  
Y Horikawa ◽  
S Naruse ◽  
C Tanaka ◽  
K Hirakawa ◽  
H Nishikawa
Keyword(s):  
Brain Edema ◽  
Relaxation Times ◽  
Proton Nmr ◽  
Nmr Relaxation ◽  
Ischemic Brain ◽  
Ischemic Brain Edema ◽  
Nmr Relaxation Times

Field-Dependent Proton NMR Relaxation in Aqueous Solutions of Ni(II) Ions. A New Interpretation

1996 ◽  
Vol 121 (2) ◽  
pp. 108-113 ◽  
Author(s):  
J. Svoboda ◽  
T. Nilsson ◽  
J. Kowalewski ◽  
P.-O. Westlund ◽  
P.T. Larsson
Keyword(s):  
Aqueous Solutions ◽  
Proton Nmr ◽  
Nmr Relaxation ◽  
Field Dependent ◽  
New Interpretation

Reduction in the proton NMR relaxation times of dystrophic muscles following functional improvement

1984 ◽  
Vol 2 (3) ◽  
pp. 250-251 ◽  
Author(s):  
L.K. Misra ◽  
P.A. Narayana ◽  
D. Bearden ◽  
T. Egan ◽  
R.P. Munjaal ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Proton Nmr ◽  
Nmr Relaxation ◽  
Functional Improvement ◽  
Nmr Relaxation Times

Proton NMR relaxation of the nonaqueous component of human blood serum

1995 ◽  
Vol 120 (4) ◽  
pp. 1073-1076
Author(s):  
M. G. Gangardt ◽  
N. F. Karyakina ◽  
A. S. Pavlov ◽  
E. A. Papish
Keyword(s):  
Blood Serum ◽  
Human Blood ◽  
Proton Nmr ◽  
Nmr Relaxation ◽  
Human Blood Serum

Proton NMR relaxation studies on several nitroxyl-water systems

1978 ◽  
Vol 7 (3) ◽  
pp. 197-204 ◽  
Author(s):  
E. v. Goldammer ◽  
W. Kreysch ◽  
H. Wenzel
Keyword(s):  
Proton Nmr ◽  
Nmr Relaxation ◽  
Water Systems ◽  
Relaxation Studies
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