BROADBAND EPR SPECTROMETER WITH DIGITAL SUBSAMPLING

这项提议是由设备设计驱动的。它基于PI和他的同事们最近的一篇论文：J.S.Hyde，H.S.Mchaourab，T.Camenisch，J.J.Ratke，R.W.Cox和W.Froncisz，EPR检测通过时间锁定的子采样，科学仪器评论69,2622-2628,1998。一方面，本文确立了概念的可行性，另一方面，出现了一些需要进一步研究和开发的工程问题。长远的目标是开发一种新的通用电子顺磁共振(EPR)光谱仪，它基于现代信号采集和信号处理方法，并在具有非常大存储容量的非常高速的个人计算机上。预计所有EPR光谱仪最终都将基于这项提案中介绍的想法。时间锁定亚采样(TLSS)检测的特点包括：(1)相对于传统光谱仪，灵敏度提高了约3倍；(2)同时收集自旋系统对场调制的响应的所有谐波，包括同相和异相的色散和吸收，仅受可调参数的限制；(3)宽带，使其成为探测瞬变物种光谱的理想选择；(4)无需初始信号平均即可实现数据的全数字化检测和存储。这三个具体目标涉及：(1)仪器的建造；(2)仪器的工程研究，并在整个供资期间进行额外的升级；(3)通过TLSS检测实现的3个生物医学应用。这些应用不仅对其本身感兴趣，而且将是对该仪器性能的有力考验。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)过氧亚硝酸根化学的动力学；(Iii)蛋白质结构波动的测量。电子顺磁共振波谱是研究蛋白质和大分子集合体结构和动力学的一种通用方法。这是唯一可以毫不含糊地检测生物中自由基形成的方法。它有助于在基本的基础层面上进行与健康有关的研究。

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.