DEVELOPMENT OF MICRO-WAXS AND MICRO-SAXS SET-UP

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 BiOCAT项目核心项目2的AIM2是时间分辨小角X射线散射。微流体技术与小角X射线散射的结合使用使探测微秒时间尺度成为可能。要使这些技术发挥作用，X射线束大小必须小于流体路径，以减少背景并收集良好的数据质量。在这里，我们评估了微探针光学在Micro-WAXS实验中的使用。在一个直径2.8 mm的光束挡板上安装了一个二极管来记录传输。样品检测器间距为280 mm。光束聚焦在探测器上。在流动细胞上负载8 mg/ml折叠细胞色素C溶液。得到了高质量的散射数据，Rg值与文献相符。计划中的设置改进包括将Kb镜向上游移动，以增加样品到检测器的距离，以获得较小的Q值。我们还将把X射线光束聚焦到探测器和样品之间的一个点上，以减小样品处的光束尺寸，并获得沿毛细管更好的空间分辨率以及更好的反应时间分辨率。我们还将测试一种新的微流控混合器。委托测试计划在11月下旬进行，为细胞色素C折叠的时间分辨研究收集数据计划在12月进行。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Aim2 of Core Project 2 for the BiOCAT project is Time Resolution Small-Angle X-ray Scattering. The combined use of microfluidics technique with Small-Angle X-ray Scattering allows probing microsecond timescales. For these techniques to work, the X-ray beam size has to be smaller than the fluid path to reduce the background and collect good data quality. Here we evaluated the use of the microprobe optics for micro-WAXS experiments. A diode was installed on a 2.8mm diameter beam stop to record transmission. The sample detector distance was 280mm. The beam was focused on the detector. 8mg/ml folded cytochrome C solution was loaded on the flow cell. Good quality scattering data were obtained with Rg values in agreement with the literature. Planned improvements to the setup include moving the KB mirrors upstream to increase the sample to detector distance to access smaller Q values. We will also focus the X-ray beam to a spot between the detector and the sample to decrease the beam size at the sample and achieve a better spatial resolution along the capillary as well as better temporal resolution of the reaction. We will also \test a new microfluidic mixer. Commisioning tests are planned for late Novemerb with data collection for time resolved studies of folding of cytochrome C are planned for December.