Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26506, USA; In Vivo Multifunctional Magnetic Resonance Center at Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA.
In Vivo Multifunctional Magnetic Resonance Center at Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506, USA.
J Magn Reson. 2022 Dec;345:107308. doi: 10.1016/j.jmr.2022.107308. Epub 2022 Oct 21.
Automation has become an essential component of modern scientific instruments which often capture large amounts of complex dynamic data. Algorithms are developed to read multiple sensors in parallel with data acquisition and to adjust instrumental parameters on the fly. Decisions are made on a time scale unattainable to the human operator. In addition to speed, automation reduces human error, improves the reproducibility of experiments, and improves the reliability of acquired data. An automatic digital control (ADiC) was developed to reliably sustain critical coupling of a resonator over a wide range of time-varying loading conditions. The ADiC uses the computational power of a microcontroller that directly communicates with all system components independent of a personal computer (PC). The PC initiates resonator tuning and coupling by sending a command to MC via serial port. After receiving the command, ADiC establishes critical coupling conditions within approximately 5 ms. A printed circuit board resonator was designed to permit digital control. The performance of the resonator together with the ADiC was evaluated by varying the resonator loading from empty to heavily loaded. For the loading, samples containing aqueous sodium chloride that strongly absorb electromagnetic waves were used. A previously reported rapid scan (RS) electron paramagnetic resonance (EPR) imaging instrument was upgraded by the incorporation of ADiC. RS spectra and an in vivo image of oxygen in a mouse tumor model have been acquired using the upgraded system. ADiC robustly sustained critical coupling of the resonator to the transmission line during these measurements. The design implemented in this study can be used in slow-scan and pulsed EPR with modifications.
自动化已经成为现代科学仪器的重要组成部分，这些仪器通常可以捕获大量复杂的动态数据。开发算法是为了并行读取多个传感器，同时进行数据采集，并实时调整仪器参数。决策是在人类操作员无法达到的时间尺度上做出的。除了速度之外，自动化还可以减少人为错误，提高实验的可重复性，并提高获取数据的可靠性。为了可靠地维持谐振器在广泛的时变加载条件下的临界耦合，开发了自动数字控制（ADiC）。ADiC 利用微控制器的计算能力，直接与所有系统组件进行通信，而无需与个人计算机（PC）进行通信。PC 通过串行端口向 MC 发送命令来启动谐振器调谐和耦合。收到命令后，ADiC 将在大约 5 毫秒内建立临界耦合条件。设计了一个印刷电路板谐振器以实现数字控制。通过将含有强烈吸收电磁波的氯化钠水溶液的样品从空载到重载，评估了谐振器及其 ADiC 的性能。使用升级后的系统获得了快速扫描（RS）电子顺磁共振（EPR）成像仪器的 RS 光谱和体内小鼠肿瘤模型中氧的图像。ADiC 在这些测量中稳健地维持了谐振器与传输线的临界耦合。本研究中实施的设计可以在经过修改后用于慢扫描和脉冲 EPR。
