1093 SENSITIVITY OF MAGNETIC RESONANCE PROTON SPIN-SPIN RELAXATION TIME AS AN INDEX OF MUSCLE ACTIVATION

1994 ◽  
Vol 26 (Supplement) ◽  
pp. S194
Author(s):  
G. Yue ◽  
A. L. Alexander ◽  
D. H. Laidlaw ◽  
A. F. Gmitro ◽  
E. C. Unger ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Magnetic Resonance ◽  
Spin Relaxation ◽  
Muscle Activation ◽  
Proton Spin ◽  
Spin Relaxation Time

Sensitivity of muscle proton spin-spin relaxation time as an index of muscle activation

1994 ◽  
Vol 77 (1) ◽  
pp. 84-92 ◽  
Author(s):  
G. Yue ◽  
A. L. Alexander ◽  
D. H. Laidlaw ◽  
A. F. Gmitro ◽  
E. C. Unger ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Spin Relaxation ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Proton Spin ◽  
Spin Relaxation Time ◽  
Elbow Flexor ◽  
Flexor Muscles ◽  
Elbow Flexor Muscles ◽  
Long Head

The purpose of this study was to determine the minimum number of contractions that are needed to detect an increase in the muscle proton spin-spin relaxation time (T2) at a given exercise intensity. Five healthy human subjects performed five sets of an exercise that included concentric and eccentric contractions of the elbow-flexor muscles with loads that were 25 or 80% of maximum. With the 80% load, the five sets involved 1, 2, 5, 10, or 20 repetitions of the exercise; with the 25% load the five sets were 2, 5, 10, 20, or 40 repetitions. The upper arm of each subject was imaged before and immediately after each set of the exercise. Spin-echo images (repetition time/echo time = 2,000 ms/30, 60, 90, and 120 ms) were collected using an extremity coil, and T2 values were calculated. The signal intensity was measured from the elbow-flexor and -extensor muscles and from the bone marrow of the humerus. With the 80% load, T2 increased in the short head of the biceps brachii after two repetitions of the elbow exercise and after five repetitions in the brachialis and the long head of the biceps brachii. With the 25% load, T2 became longer after five repetitions of the exercise for the short head of the biceps brachii and after 10 repetitions for the brachialis and the long head of the biceps brachii. T2 varied linearly with the number of contraction repetitions for each of the elbow-flexor muscles at either load (r2 > or = 0.97, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Rotation-induced recovery and bleaching in magnetic resonance

2015 ◽  
Vol 17 (9) ◽  
pp. 6415-6422 ◽  
Author(s):  
Angel J. Perez Linde ◽  
Srinivas Chinthalapalli ◽  
Diego Carnevale ◽  
Geoffrey Bodenhausen
Keyword(s):  
Relaxation Time ◽  
Magnetic Resonance ◽  
Spin Relaxation ◽  
Sharp Decrease ◽  
Proton Spin ◽  
Spin Relaxation Time ◽  
Magic Angle

A sharp decrease of the longitudinal proton spin relaxation time T1(1H) is observed at 100 K when frozen mixtures of glycerol and H2O doped with lanthanides are made to rotate slowly about the magic angle, in a manner that is reminiscent of spin refrigerators.

Proton spin-spin relaxation time of peel and flesh of navel orange varieties exposed to freezing temperature

2005 ◽  
Vol 85 (14) ◽  
pp. 2482-2486 ◽  
Author(s):  
Prem N Gambhir ◽  
Young J Choi ◽  
David C Slaughter ◽  
James F Thompson ◽  
Michael J McCarthy
Keyword(s):  
Relaxation Time ◽  
Spin Relaxation ◽  
Freezing Temperature ◽  
Proton Spin ◽  
Spin Relaxation Time ◽  
Navel Orange

scholarly journals 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

2018 ◽  
Vol 55 (2) ◽  
pp. 208-216 ◽  
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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