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Techniques for Probing the Processes by Which Microwaves Interact with Chemical and Biological Systems

机译：探测微波与化学和生物系统相互作用过程的技术

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Microwave heating is a relatively mature field and is theoretically well understood. However,udrecently there has been debate as to whether microwaves can interact with chemical andudbiological systems by means other than heating alone. There is some theoretical justification forudsuch interactions but experimental evidence is often unreliable due to poor or non-existentudmeasurement of heating and/or poor control experiments. Therefore improved techniques forudprobing these systems are required.udOne of the reasons why microwave-assisted chemistry is poorly understood is that there is littleudavailable dielectric property data even for common solvents. A simple method for theudmeasurement of the dielectric spectra of liquids was verified and used to probe a roomudtemperature ionic liquid and a chemical mixture used in a stage of a microwave-heated industrialudprocess. The temperature and frequency dependence of the dielectric properties explained theudobserved rapid microwave heating of the ionic liquid and the relative failure of the process as audresult of changing the irradiation conditions in order to scale it up.udTemperature measurement during microwave-assisted chemistry, whilst crucial to theudelucidation of non-thermal effects, is problematic. A method of component specific or spatiallyresolvedudthermometry during microwave heating of solid-phase organic synthesis (SPOS)udsuspensions has been developed. Measurements of the temperature-dependent lifetime of audfluorophore covalently attached to SPOS resin beads yield temperature values accurate to withinudaround 0.5°C. Selective microwave heating of the resin was not observed, even for a systemudartificially designed to have significant dielectric inhomogeneity.udTechniques for the in situ and in vitro probing of model biological systems offer significantudimprovements over previous methods used to determine the possibility of microwaves effectingudliving things by non-thermal means. Thermally induced changes in the structures of a lipid and audglobular protein were followed by small angel neutron scattering and circular dichroismudrespectively during microwave exposure. No evidence for non-thermal effects was obtained.
机译：微波加热是一个相对成熟的领域，并且在理论上得到了很好的理解。但是，最近有关于微波是否可以通过单独加热以外的方式与化学和生物系统相互作用的争论。这种相互作用有一些理论上的证明，但是由于加热的测量不良或不存在和/或控制实验不良，实验证据常常是不可靠的。因此，需要改进的技术来探测这些系统。对微波辅助化学知之甚少的原因之一是，即使对于普通溶剂，也几乎没有可利用的介电特性数据。检验了测量液体介电谱的简单方法，并将其用于探测室温离子液体和在微波加热的工业过程中使用的化学混合物。介电性能对温度和频率的依赖性解释了不可观测的离子液体的快速微波加热以及该过程的相对失败，因为改变了辐照条件以使其规模扩大。 ud在微波辅助下的温度测量化学虽然对非热效应的阐明至关重要，但仍存在问题。开发了一种在微波加热固相有机合成（SPOS）悬浮液的过程中，通过组分特异性或空间分辨测热法的方法。对共价连接至SPOS树脂珠粒的ud荧光团的温度依赖性寿命进行测量，得出的温度值精确到0.5℃左右。即使对于专门设计为具有明显介电不均一性的系统，也未观察到树脂的选择性微波加热。 ud用于对模型生物系统进行原位和体外探测的技术相对于以前的方法（确定方法是否可行）进行了重大改进。微波通过非热手段影响消灭事物。在微波暴露期间，热诱导的脂质和球状蛋白质结构变化之后分别发生小天使中子散射和圆二色性。没有获得非热效应的证据。

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    Kay Philip E;

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  • 年度 2007
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