Magnetic field dependence of proton spin-lattice relaxation times
Magnetic field dependence of proton spin-lattice relaxation times
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DOI：
10.1002/mrm.10185
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发表时间：
2002-07-01
影响因子：
3.3
通讯作者：
Bryant, RG
中科院分区：
文献类型：
--
作者：
Korb, JP;Bryant, RG
组织中水-质子自旋-晶格驰豫速率(1/T-1)的磁场依赖性是由于组织中旋转固定的成分的质子的磁耦合。因此，水质子的磁场依赖关系(1/T-1)是组织的固体成分的(1/T-1)比率的场依赖关系的比例报告。质子自旋-晶格驰豫速率一般可表示为幂定律：1/T(1)omega=Aomega(-b)，其中b通常被发现在0.5-0.8的范围内。我们已经证明，这一幂定律可能自然地产生于调节质子偶极-偶极耦合的生物聚合物中沿主干的局域结构涨落。蛋白质中的质子形成了一个自旋通信网络，用小于欧几里德维度的分维来描述。该模型定量地解释了不同水分含量下固定化蛋白质体系中测量到的质子自旋-晶格驰豫速率，为理解组织等动态非均相体系中质子自旋-晶格驰豫速率的参数依赖性提供了基本依据。(C)2002年Wiley-Liss，Inc.
The magnetic field dependence of the water-proton spin-lattice relaxation rate (1/T-1) in tissues results from magnetic coupling to the protons of the rotationally immobilized components of the tissue. As a consequence, the magnetic field dependence of the water-proton (1/T-1) is a scaled report of the field dependence of the (1/T-1) rate of the solid components of the tissue. The proton spin-lattice relaxation rate may be represented generally as a power law: 1/T(1)omega = Aomega(-b), where b is usually found to be in the range of 0.5-0.8. We have shown that this power law may arise naturally from localized structural fluctuations along the backbone in biopolymers that modulate the proton dipole-dipole couplings. The protons in a protein form a spin communication network described by a fractal dimension that is less than the Euclidean dimension. The model proposed accounts quantitatively for the proton spin-lattice relaxation rates measured in immobilized protein systems at different water contents, and provides a fundamental basis for understanding the parametric dependence of proton spin-lattice relaxation rates in dynamically heterogeneous systems, such as tissues. (C) 2002 Wiley-Liss, Inc.