scholarly journals Properties of the cupric sites in bovine superoxide dismutase studied by nuclear-magnetic-relaxation measurements

1979 ◽  
Vol 177 (1) ◽  
pp. 303-309 ◽  
Author(s):  
N Boden ◽  
M C Holmes ◽  
P F Knowles
Keyword(s):  
Superoxide Dismutase ◽  
Water Molecule ◽  
Magnetic Relaxation ◽  
Nuclear Relaxation ◽  
Histidine Residue ◽  
Relaxation Rates ◽  
Cyanide Concentration ◽  
Relaxation Measurements ◽  
Bovine Erythrocytes ◽  
Frequency Temperature

Proton nuclear-relaxation rates have been measured as a function of frequency, temperature, pH and cyanide concentration in aqueous solutions of superoxide dismutase from bovine erythrocytes. The results show that, whereas for pH less than or equal to 9 only one water molecule is bound to each Cu2+ ion, at higher pH a second co-ordination site for OH- becomes available; it is proposed that this involves cleavage of the bond between Cu2+ and the histidine residue that bridges to Zn2+.

Ion-Ion De-Association and Association of Strong Electrolytes at High Dilution from Nuclear Magnetic Relaxation Measurements

1995 ◽  
Vol 50 (4-5) ◽  
pp. 487-501 ◽  
Author(s):  
E. Detscher ◽  
H. G. Hertz ◽  
M. Holz ◽  
Xi-an Mao
Keyword(s):  
Magnetic Relaxation ◽  
Ion Association ◽  
Solute Concentration ◽  
Relaxation Rates ◽  
High Dilution ◽  
Hückel Theory ◽  
Relaxation Measurements ◽  
Strong Electrolytes ◽  
Anion Interaction ◽  
Theoretical Considerations

Abstract Proton magnetic relaxation rates in the system N(CH)3)4Br/NiBr2/D2O, N(CH3)4Br/MnBr2/ D2O, Ni(00CCH3)2/D2O and Mn(00CCH3)2/D2O have been measured as a function of the solute concentration in the range 0.002 < c* ⪍ 1 m. Division by the concentration c* and by a quantity characterizing the ionic motion yields the association parameter (4-parameter). A decreases and increases with decreasing concentration for the systems involving cation-cation and cation-anion interaction, respectively. The relaxation rates of 35C1-, 133Cs+ , and 25Mg++ in diamagnetic aqueous solutions have also been measured down to high dilution. Here as well in most cases we have found an increase of the A-parameter with decreasing salt concentration, indicating ion-ion association at high dilution. A comparison with the results of the Debye-Hückel theory is given; there is qualitative agreement. Our experimental results for 35C1- generally do not support theoretical considerations in the literature, where a Cl--Cl- association was postulated

63,65Cu NMR and NQR in YBa2Cu3O7-δ

1987 ◽  
Vol 99 ◽  
Author(s):  
W. W. Warren ◽  
R. E. Walstedt ◽  
R. F. Bell ◽  
G. F. Brennert ◽  
R. J. Cava ◽  
...  
Keyword(s):  
Superconducting State ◽  
High Field ◽  
Nuclear Relaxation ◽  
Relaxation Rates ◽  
Structural Units ◽  
Nmr Spectrum ◽  
Electron Pairing

ABSTRACTNMR and NQR results are reported for 63,65Cu in YBa2Cu3O7-δ. Analysis of the high-field NMR spectrum indicates substantial disorder in the copper-oxygen planes. Nuclear relaxation rates are significantly different for copper in the chains and planes both above and below Tc and yield sharply different electron pairing energies on these structural units in the superconducting state.

Simulation of magnetic relaxation measurements of tetragonal and thin films

1998 ◽  
Vol 11 (11) ◽  
pp. 1241-1250 ◽  
Author(s):  
M Holiastou ◽  
M Pissas ◽  
D Niarchos ◽  
P Haibach ◽  
U Frey ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Relaxation ◽  
Relaxation Measurements

Magnetic relaxation measurements on tissue mimicking phantoms: comparison between different fitting algorithms in MRI T2 calculations

2014 ◽  
Vol 30 ◽  
pp. e118-e119
Author(s):  
G. Kalaitzakis ◽  
L. Kavroulakis ◽  
T. Boursianis ◽  
S. Veneti ◽  
L. Kontopodis ◽  
...  
Keyword(s):  
Magnetic Relaxation ◽  
Relaxation Measurements

Determination of the Spectral Density FunctionJ1(ω)in SolidHe3from Nuclear-Relaxation Measurements

1966 ◽  
Vol 146 (1) ◽  
pp. 244-253 ◽  
Author(s):  
Robert C. Richardson ◽  
André Landesman ◽  
Earle Hunt ◽  
Horst Meyer
Keyword(s):  
Spectral Density ◽  
Nuclear Relaxation ◽  
Relaxation Measurements

Towards solvent tuning of slow magnetic relaxation and ferroelectric properties in a dysprosium metal–organic framework system

2019 ◽  
Vol 234 (1) ◽  
pp. 33-41
Author(s):  
Lina Zhang ◽  
Shuyan Guan ◽  
Yunchang Fan ◽  
Chenxia Du ◽  
Dan Zhao ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Molecule ◽  
Magnetic Relaxation ◽  
Metal Organic Framework ◽  
Ferroelectric Properties ◽  
Relaxation Rates ◽  
Slow Magnetic Relaxation ◽  
Metal Organic ◽  
Solvent Molecules ◽  
Organic Framework

Abstract A new dysprosium metal–organic framework {[Dy2(L)3(H2O)4]·(acetone)2·(H2O)3}n (Dy2-Acetone) with single-molecule magnet and ferroelectric properties was synthesized through a solvent-induced single-crystal-to-single-crystal (SCSC) transformation. Notably, exchange of the coordinated and guest solvent molecules lead to different magnetic relaxation and ferroelectric properties in the dysprosium MOF system, Dy2-DMF and Dy2-Acetone. Study reveals that the tunable magnetic relaxation behaviors are most likely a result of different local coordination sphere and lattice solvent molecules within the pores which influenced and tuned the relaxation rates of the magnetization. Moreover, disparate polar solvent molecules confined in the MOFs may be the key factors for their different ferroelectric properties.

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