BROADBAND EPR SPECTROMETER WITH DIGITAL SUBSAMPLING

该提案是器械设计驱动的。它基于PI和他的同事最近的一篇论文：Hyde，H. S. Mchaourab，T. Camenisch，J. J. Ratke，R. W.考克斯和W. Froncisz，通过时间锁定子采样的EPR检测，科学仪器评论69，2622-2628，1998。 一方面，该文件确定了这些概念的可行性，另一方面，出现了一些工程问题，需要进一步的研究和开发。广泛的长期目标是开发一种新的通用电子顺磁共振（EPR）光谱仪的基础上，现代信号采集和信号处理方法，也非常高速的个人计算机具有非常大的存储容量。预计所有EPR光谱仪最终都将基于该提案中介绍的想法。时间锁定子采样（TLSS）检测的特征包括：（i）相对于常规光谱仪增加约3倍的灵敏度;（ii）同时收集自旋系统对场调制的响应的所有谐波，对于色散和吸收两者都是同相和异相的，仅受可调参数的限制;（iii）宽带性，使其成为瞬态物质光谱检测的理想选择;（iv）完全数字化检测和数据存储，无需初始信号平均。 这三个具体目标包括：（i）仪器的建造;（ii）在整个资助期间对仪器进行工程研究并进行额外升级;（iii）通过TLSS探测实现三种生物医学应用。 这些应用不仅本身令人感兴趣，而且将是对仪器能力的有力测试。它们涉及生物医学EPR研究的三个广泛领域：（i）含铜酶中的氮连接;（ii）过氧亚硝酸盐化学的动力学;（iii）蛋白质结构波动的测量。EPR光谱是研究蛋白质和大分子组装体的结构和动力学的一般方法。它是唯一可以明确地检测生物体中自由基形成的方法。它在基础一级促进与健康有关的研究。

This proposal is device design driven. It is based on a recent paper by the PI and his colleagues: J. S. Hyde, H. S. Mchaourab, T. Camenisch, J. J. Ratke, R. W. Cox, and W. Froncisz, EPR detection by time-locked sub- sampling, Review of Scientific Instruments 69, 2622-2628, 1998. On the one hand, this paper established feasibility for the concepts, while on the other, a number of engineering issues arose that require additional research and development. The broad long-term goal is to develop a new general purpose electron paramagnetic resonance (EPR) spectrometer based on modem signal acquisition and signal processing methods and also on very high speed personal computers with very large memory capacity. It is expected that all EPR spectrometers will eventually be based on the ideas introduced in this proposal. Features of time-locked sub-sampling (TLSS) detection include (i) increased sensitivity relative to conventional spectrometers by about a factor of 3; (ii) simultaneous collection of all harmonics of the response of the spin system to field modulation, both in- and out-of-phase for both dispersion and absorption, limited only by adjustable parameters; (iii) broadbandedness, making it ideal for detection of spectra from transient species; (iv) totally digital detection and storage of data without initial signal averaging. The three specific aims involve (i) construction of the instrument; (ii) engineering studies of the instrument with additional upgrades throughout the funding period; and (iii) three biomedical applications made possible by TLSS detection. These applications are not only of interest in themselves, but also will be powerful tests of the capabilities of the instrument. They address three broad areas of biomedical EPR research: (i) nitrogen ligation in copper-containing enzymes; (ii) kinetics of peroxynitrite chemistry; and (iii) measurement of fluctuations in protein structures. EPR spectroscopy is a general approach to the study of the structure and dynamics of proteins and macromolecular assemblies. It is the only method that can detect the formation of free radicals in biology unambiguously. It contributes to health-related research at the basic fundamental level.