Magnetic Resonance Microscopy - Spatially Resolved NMR Techniques and Applications
Magnetic Resonance Microscopy - Spatially Resolved NMR Techniques and Applications
复制标题
磁共振显微镜 - 空间分辨核磁共振技术和应用
DOI：
10.1002/9783527626052.ch24
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Britton M
中科院分区：
文献类型：
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作者：
Britton M
在自催化和扩散之间存在耦合的反应中形成行波和化学波[1]，是一种反应-扩散(RD)现象。当反应在局部区域被启动或“激发”时，就会出现行波前锋。在这个区域，自催化物种的浓度迅速增加，随着自催化剂扩散到邻近区域，自催化过程重复，导致化学前沿的传播。在反应溶液返回到其初始状态以准备发生另一次激发的系统中会出现多个波。这种反应最著名的例子是别洛索夫-扎博廷斯基反应[2]。反应扩散过程使分子或离子的扩散比单独通过扩散发生得更快。之所以出现这种繁殖的增强，是因为在反馈步骤接管之前，只需要少量的自动催化剂扩散到一个区域，该物种的浓度迅速增加。反应-扩散过程被认为是许多生物系统信号机制的基础，这些生物系统利用了这种增强的传播速度[3]。正是这些非线性和振荡化学反应作为生物过程中波动和振荡行为的模型，如趋化性和钙波，是这一领域许多研究背后的驱动力。
Traveling chemical waves and fronts form in reactions where there is a coupling between autocatalysis and diffusion [1] and are a type of reaction–diffusion (RD) phenomenon. Traveling fronts occur when the reaction is initiated, or ‘excited’, in a localized region. The concentration of an autocatalytic species rapidly increases in this region, and as the autocatalyst diffuses into neighboring regions the autocatalytic process is repeated, resulting in the propagation of a chemical front. Multiple waves occur in systems where the reacting solution returns to its initial state ready for another excitation to occur. The most famous example of this type of reaction is the Belousov–Zhabotinksy reaction [2]. Reaction–diffusion processes enable the spreading of molecules or ions to occur more rapidly than via diffusion alone. This enhancement in propagation arises because only small amounts of the autocatalyst need diffuse into a region before the feedback step takes over and the concentration of that species rapidly increases. Reaction–diffusion processes are believed to underlie the signaling mechanisms in many biological systems, which exploit this enhanced propagation velocity [3]. It is the application of these nonlinear and oscillatory chemical reactions as models for wave and oscillatory behavior in biological processes, such as chemotaxis and calcium waves, that is the driving force behind much of the research in this area.