BIOLOGICAL APPLICATIONS OF A COMPUTER CONTROLLED ANALYTICAL ELECTRON MICROSCOPE

已经进行了测试以确定元素的极限 GaTan平行探测电子能量损失的可探测性 安装在BEIB日立200keV分析仪上的光谱仪(EELS) 电子显微镜。从一系列标准中记录数据 样品，也可以从冷冻干燥的冰冻切片获得 Reichert F4C冷冻切片机。光谱是通过使用 消除通道间增益的“第二差分”方法 1024通道光电二极管阵列中的波动。事情就是这样 有可能检测到具有极小特征的核心边缘 峰值/背景(例如0.001)。与能源进行了比较- 同时记录的色散X射线能谱。事实证明， 钙和铁的检测都具有相当的灵敏度。 使用这两种技术。因此，我们预计鳗鱼将拥有 这些元素在高分辨率下具有卓越的灵敏度 真空发生器的场发射STEM的应用。 对辐射引起的质量损失进行了进一步的研究 标记的神经递质和神经激素中的氟 最终的目标是在细胞中定位这些化合物。并行- 录制的鳗鱼在敏感度方面比 常规连续记录的鳗鱼，并可能进行这样的实验 可行。

Tests have been performed to determine limits of elemental detectability for the Gatan parallel-detection electron energy loss spectrometer (EELS) fitted on the BEIB Hitachi 200-keV analytical electron microscope. Data were recorded from a series of standard samples and also from freeze-dried cryosections obtained with a Reichert F4C cryoultramicrotome. Spectra were obtained using a "second difference" method that eliminates channel-to-channel gain fluctuations in the 1024-channel photodiode array. It was thus possible to detect characteristic core-edges with extremely small peak/background (e.g. 0.001). Comparisons were made with energy- dispersive x-ray spectra recorded concurrently. It was shown that both calcium and iron could be detected with comparable sensitivity using the two techniques. We therefore expect EELS to have superior sensitivity for these elements in high resolution applications with the Vacuum Generators Field emission STEM. Further studies have been made on radiation induced mass loss of fluorine in labelled neurotransmitters and neurohormones with the eventual aim of localizing these compounds in cells. Parallel- recorded EELS provides a great improvement in sensitivity over conventional serial-recorded EELS and may make such experiments feasible.