Nuclear magnetic resonance spin-spin relaxation time in hydrated protein powders. A two site dynamic exchange model

Samples of human and bovine cartilage have been examined using magnetic resonance imaging to determine the proton nuclear magnetic resonance spin–lattice relaxation time, T 1 , as a function of depth within through the cartilage tissue. T 1 was measured at five to seven temperatures between 8 and 38°C. From this, it is shown that the T 1 relaxation time is well described by Arrhenius-type behaviour and the activation energy of the relaxation process is quantified. The activation energy within the cartilage is approximately 11 ± 2 kJ mol −1 with this notably being less than that for both pure water (16.6 ± 0.4 kJ mol −1 ) and the phosphate-buffered solution in which the cartilage was immersed (14.7 ± 1.0 kJ mol −1 ). It is shown that this activation energy increases as a function of depth in the cartilage. It is known that cartilage composition varies with depth, and hence, these results have been interpreted in terms of the structure within the cartilage tissue and the association of the water with the macromolecular constituents of the cartilage.

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Modeling of proton spin relaxation in muscle tissue using nuclear magnetic resonance spin grouping and exchange analysis

Biophysical Journal ◽

10.1016/s0006-3495(86)83450-6 ◽

1986 ◽

Vol 50 (1) ◽

pp. 181-191 ◽

Cited By ~ 26

Author(s):

W.T. Sobol ◽

I.G. Cameron ◽

W.R. Inch ◽

M.M. Pintar

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Spin Relaxation ◽

Muscle Tissue ◽

Proton Spin ◽

Resonance Spin ◽

Nuclear Magnetic

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Influence of drying–wetting cycles on soil-water characteristic curve of undisturbed granite residual soils and microstructure mechanism by nuclear magnetic resonance (NMR) spin-spin relaxation time (T2) relaxometry

Canadian Geotechnical Journal ◽

10.1139/cgj-2016-0614 ◽

2018 ◽

Vol 55 (2) ◽

pp. 208-216 ◽

Cited By ~ 14

Author(s):

Lingwei Kong ◽

Hossain Md. Sayem ◽

Huihui Tian

Keyword(s):

Nuclear Magnetic Resonance ◽

Relaxation Time ◽

Magnetic Resonance ◽

Size Distribution ◽

Soil Water ◽

Spin Relaxation ◽

Characteristic Curve ◽

Spin Relaxation Time ◽

Residual Soils ◽

Soil Water Characteristic Curve

Due to the formational environment and climatic variability, granite residual soils with grain-size distribution ranging from gravel to clay undergo multiple drying–wetting cycles. The influences of multiple drying–wetting cycles on the soil-water characteristic curve (SWCC) and pore-size distribution (POSD) of undisturbed granite residual soils are investigated using the pressure plate test and nuclear magnetic resonance (NMR) spin-spin relaxation time (T2) distribution measurement, respectively. Results show that the water-retention capacity and air-entry value decrease and pores become more uniform with increasing drying–wetting cycles. After four drying–wetting cycles, the soil reaches a nearly constant state. The POSD change of multiple drying–wetting cycle samples is consistent with the SWCC of the soils. Furthermore, a modified van Genuchten model in terms of cumulative pore volume is used to obtain the best-fit POSD of the drying–wetting cycle samples. The shape and changing tendency of both curves of SWCC and POSD are quite similar and achieved a better correlation. It can be concluded that the SWCC is strongly dependent on the POSD of the soil and NMR T2 relaxometry can be used as an alternative to the assessment of microstructural variation of residual soils subjected to the periodic drying and wetting process.

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