Rodin V V, Knight D P
Biofizika. 2004 Sep-Oct;49(5):800-8.
The molecular mobility of water in fibres of natural silk (Bombyx mori) was studied by the double-quantum-filtered (DQF) and single-pulse 1H NMR techniques. The results obtained showed a slow motion of water molecules and their strong interaction with silk macromolecules. At different model functions for resonance lineshape in 1H NMR spectra, the influence of signal linewidth on the estimation of relaxation times and cross-relaxation parameters was considered. The observed 1H DQF NMR signal in B. mori silk fibres (BC = 0.065) indicated a local order and anisotropic motion of water molecules, which leads to 1H-1H dipolar interactions in natural silk fibers due to the creation of the second-rank tensors (T(2,+1), T(2,-1)). DQF spectra were the difference of two Lorentzians with different linewidths and were analyzed using the theory of 1H DQF NMR and the data on residual dipolar interactions in systems with the anisotropic mobility of water molecules. The residual dipolar interactions was insignificant and, as the humidity increased (0.18), no DQF-signals and residual dipolar interactions were observed.
采用双量子滤波（DQF）和单脉冲1H NMR技术研究了天然蚕丝（家蚕）纤维中水的分子迁移率。所得结果表明水分子运动缓慢且与丝大分子有强烈相互作用。在1H NMR谱中共振线形的不同模型函数下，考虑了信号线宽对弛豫时间和交叉弛豫参数估计的影响。在家蚕丝纤维中观察到的1H DQF NMR信号（BC = 0.065）表明水分子具有局部有序和各向异性运动，由于二阶张量（T(2,+1)，T(2,-1)）的产生，这导致天然丝纤维中存在1H-1H偶极相互作用。DQF谱是两个具有不同线宽的洛伦兹曲线的差值，并使用1H DQF NMR理论以及水分子各向异性迁移率系统中残余偶极相互作用的数据进行分析。残余偶极相互作用不显著，并且随着湿度增加（0.18），未观察到DQF信号和残余偶极相互作用。
