CHARACTERIZATION OF FROZEN-HYDRATED SPECIMENS BY EELS

建立了一种测定亚细胞含水量的方法 冷冻水合组织的隔室取决于 水与有机物之间的价态激发能量损失谱 细胞的组成部分。 单散射分布首先是 从冰和蛋白质中通过应用傅里叶对数 反褶积技术 然后，得到的参考光谱为 通过将贝特求和规则应用于差分振荡器来归一化 为了推导出微分截面。 直接 水含量的估计可以通过应用最小二乘法来获得 拟合算法从水合试样的光谱。 测试已经 在快速冷冻的牛血清白蛋白的薄冷冻切片上进行 标准品，含70%、80%和90%蛋白质，通过记录 场发射扫描透射平行EELS谱 电子显微镜（STEM）。 结果发现， 在测定含水量时可达到约1%。 该方法已应用于冰冻切片的红细胞和小脑 皮层

A method has been developed for measuring water content in subcellular compartments of frozen hydrated tissue that depends on variations in the valence excitation energy loss spectrum between water and the organic constituents of a cell. Single-scattering distributions are first obtained from ice and protein by applying the Fourier-logarithmic deconvolution technique. The resulting reference spectra are then normalized by applying the Bethe sum rule to the differential oscillator strengths in order to derive the differential cross sections. A direct estimate of the water content can be obtained by applying a least squares fitting algorithm to spectra from hydrated specimens. Tests have been performed on thin cryosections of rapidly frozen bovine serum albumin standards, containing 70%, 80%, and 90% protein, by recording parallel-EELS spectra in the field-emission scanning transmission electron microscope (STEM). It was found that an accuracy of approximately 1% could be achieved in the determination of water content. The method has been applied to cryosectioned erythrocytes and cerebellar cortex.