Spin Echo Measurements of Nuclear Spin Coupling in Molecules

Hahn, E. L.; Maxwell, D.E.

doi:10.1103/physrev.88.1070

Cited by 434 publications

(118 citation statements)

References 24 publications

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“…MRI may be definitive for surgical staging or medical management -in aortic dissection and descending aneurysms, but angiographic or hemodynamic assessment remains necessary for valvular disease as well as ascending and arch aneurysms. Gradient echo techniques, not available in this study, have been shown by others to improve valvular assessment (7)(8) …”

Section: Ri Correctly Demonstratedmentioning

confidence: 97%

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Abstracts-part VII (Continue in Part VIII)

1987

Proc. Soc. Magn. Reson. Med.

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INTRODUCTION A N D P U R P O S EM a g n e t i c r e s o n a n c e imaging (MRI) h a s been f o u n d to be a u s e f u l non-invasive method of d e m o n s t r a t i n g intra-2rticular structures of various joints ' . H o w e v e r , the u s e f u l n e s s of M R I i n d e m o n s t r a t i n g the changes of o s t e o a r t h r i t i s (O.A.)i n the hips has not been adequately documented. The m a i n purpose of t h i s prospective study is to a s s e s s the ability of M R I in : (a) d e l i n e a t i n g the c h a n g e s of O.A., using roentgenograms and s y m p t o m s a s c o r r e l a t e s ; (b) d e t e c t i o n of early a r t i c u l a r cartilage c h a n g e s i n a s y m p t o m a t i c older v o l u n t e e r s (over age 50), using younger n o r m a l volunteers (under age 35) a s controls. In a d d i t i o n , i n order to e s t a b l i s h a base-line for future M R s t u d y of the h i p , normal variations s u c h as the d i s t r i b u t i o n of red and y e l l o w m a r r o win the proximal f e m u r and intra-articular fat were a l s o studied. METHODST e n patients (9P, lM, m e a n age 62, range 33-78) with well-documented O . A . of the h i p s and 15 n o r m a l volunteers (9M, 6F, 9 under age 35, 1 aged 4 5 and 5 over age 50) w e r e studied.All M R scans were performed with a Diasonics M T / S 0.35T imager.For the patients with well-documented O.A. of the h i p s , all s c a n s were o b t a i n e d using a whole-body sized imaging coil, 1.7x1.7mm pixel size and 5-10mm slice thickness. For the n o r m a l volunteers, h i g h r e s o l u t i o n surface c o i l images were a l s o obtained w i t h pixel size of 0.9x0.9mmand slice thickness of 5mm. Pulse sequences used included TR10.5-2.0sec and TEa30-80msec. All patients with O.A. had roentgenograms of the h i p s within a n average of 2.2 months (range 0-4 months) of the M R examinations.A f t e r a n a l y z i n g the changes observed, a M R grading system for assessing s e v e r i t y of O.A. in the hips was developed.Using this grading system and a recognized grading system f o r roentgenograms, both with grades 0-4, 2 radiologists i n d e p e n d e n t l y graded the M R s t u d i e s and plain films separately, twice.The f u n c t i o n a l capacities of the patients were a l s o graded by the attending rheumatologist. The M R studies of the n o r m a l volunteers were carefully a n a l y z e d , concentrating especially on : (a) the thickness and continuity of the hyaline c a r t i l a g e , (b) the trabecular pattern, (c) the d i s t r i b u t i o n of red and y e l l o w m a r r o w in the proximal femur, and (d) the distribution of intra-articular fat. RESULTSunilateral total hip prostheses, therefore 18 h i p s were included in this study.There were 3, 5 and 2 patients in the Grade I V , 111 and I1 f u n c t i o n a l capacity categories respectively. The r o e n t g e n o g r a m grading s y s t e m was more accurate in predicting s y m p t o m s in the more severe cases, whereas, the MR grading was slightly more u s e f u...

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Section: Ri Correctly Demonstratedmentioning

confidence: 97%

“…This is due to indirect spinspin interactions amongst the ring protons which cause echo amplitude modulation as a function of TE (8,9).…”

Section: Resu 1 T Smentioning

confidence: 99%

Abstracts-part VII (Continue in Part VIII)

1987

Proc. Soc. Magn. Reson. Med.

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“…A detailed description of the technique can be found elsewhere [31,51,[53][54][55]. The NMR echo signal of a single freely diffusing species attenuates according to [55,56]:…”

Section: Theoretical Background Diffusion Measurements Of Associatingmentioning

confidence: 99%

Macromolecular crowding studies of amino acids using NMR diffusion measurements and molecular dynamics simulations

et al. 2015

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Molecular crowding occurs when the total concentration of macromolecular species in a solution is so high that a considerable proportion of the volume is physically occupied and therefore not accessible to other molecules. This results in significant changes in the solution properties of the molecules in such systems. Macromolecular crowding is ubiquitous in biological systems due to the generally high intracellular protein concentrations. The major hindrance to understanding crowding is the lack of direct comparison of experimental data with theoretical or simulated data. Self-diffusion is sensitive to changes in the molecular weight and shape of the diffusing species, and the available diffusion space (i.e., diffusive obstruction). Consequently, diffusion measurements are a direct means for probing crowded systems including the self-association of molecules. In this work, nuclear magnetic resonance (NMR) measurements of the self-diffusion of four amino acids (glycine, alanine, valine and phenylalanine) up to their solubility limit in water were compared directly with molecular dynamics simulations. The experimental data were then analyzed using various models of aggregation and obstruction. Both experimental and simulated data revealed that the diffusion of both water and the amino acids were sensitive to the amino acid concentration. The direct comparison of the simulated and experimental data afforded greater insights into the aggregation and obstruction properties of each amino acid.

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“…As established by Hahn, the free induction decay after a 90 ° rf pulse is the Fourier transform of a steady state signal, and the 90° r 180° pulse sequences can provide the measurement of J [5].…”

Section: Theorymentioning

confidence: 99%

J-Modulation in ID NMR ¹H Spectrum of Taurine and Aspartate Using Spin-Echo Technique

Oturak

Sağlam

Bahçelī

1999

Zeitschrift Für Naturforschung A

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This study reports on a theoretical calculation of Hahn's spin-echo experiment in case of a model A 2 Bt spin system with a strongly coupling character and gives the experimental results of one-dimension n H high-resolution NMR spectra of taurine and aspartate. The calculated amplitudes of the spinechoes for two different proton groups of taurine are given. Using results of our calculations for taurine, the computer simulations of /-modulation are implemented. It is shown that the agreement between the experimental and simulated spectra is good.

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Spin Echo Measurements of Nuclear Spin Coupling in Molecules

Cited by 434 publications

References 24 publications

Abstracts-part VII (Continue in Part VIII)

Abstracts-part VII (Continue in Part VIII)

Macromolecular crowding studies of amino acids using NMR diffusion measurements and molecular dynamics simulations

J-Modulation in ID NMR ¹H Spectrum of Taurine and Aspartate Using Spin-Echo Technique

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Spin Echo Measurements of Nuclear Spin Coupling in Molecules

Cited by 434 publications

References 24 publications

Abstracts-part VII (Continue in Part VIII)

Abstracts-part VII (Continue in Part VIII)

Macromolecular crowding studies of amino acids using NMR diffusion measurements and molecular dynamics simulations

J-Modulation in ID NMR 1H Spectrum of Taurine and Aspartate Using Spin-Echo Technique

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J-Modulation in ID NMR ¹H Spectrum of Taurine and Aspartate Using Spin-Echo Technique