A Study of Dipolar Interactions and Dynamic Processes of Water Molecules in Tendon by1H and2H Homonuclear and Heteronuclear Multiple-Quantum-Filtered NMR Spectroscopy
✍ Scribed by Uzi Eliav; Gil Navon
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 174 KB
- Volume
- 137
- Category
- Article
- ISSN
- 1090-7807
No coin nor oath required. For personal study only.
✦ Synopsis
؊1 , respectively. The results for the residual dipolar interactions were verified by repeating the above measurements at a temperature of 1.5°C, where the spectra of the H 2 O molecules were well resolved, so that the 1 H-1 H dipolar interaction could be determined directly from the observed splitting. Analysis of the MQF experiments at 1.5°C, where the proton exchange was in the intermediate regime for the 1 H-2 H dipolar interaction, confirmed the result obtained at 24°C for this interaction. A strong dependence of the intensities of the MQF signals on the proton exchange rate, in the intermediate and the fast exchange regimes, was observed and theoretically interpreted. This leads to the conclusion that the MQF techniques are mostly useful for tissues where the residual dipolar interaction is not significantly smaller than the proton exchange rate. Dependence of the relaxation times and signal intensities of the MQF experiments on the orientation of the tendon with respect to the magnetic field was observed and analyzed. One of the results of the theoretical analysis is that, in the fast exchange regime, the signal decay rates in the MQF experiments as well as in the spin echo or CPMG pulse sequences (T 2 ) depend on the orientation as the square of the second-rank Legendre polynomial.