CHARACTERIZATION OF FROZEN-HYDRATED SPECIMENS BY EELS

这项技术是我们去年发明的， 分布在薄，冷冻水合生物标本的手段， 电子能量损失谱（EELS）得到进一步发展。 这种方法依赖于量化化合价的细微变化 电子激发光谱作为组成的函数。 它涉及 确定单次散射强度，计算振子 强度，并将多个最小二乘拟合应用于参考 水和有机成分的光谱。 这项技术现在已经 扩展到光谱成像，使二维水分布 可以从水合冷冻切片中获得。 自动化处理 光谱图像数据已经实施，减少 正在研究计算时间。 技术的应用 (e.g.,分析快速冷冻肝细胞的含水量， 冷冻保存的胚胎）正在进行中。

The technique originated by us last year for measuring water distributions in thin, frozen-hydrated biological specimens by means of electron energy loss spectroscopy (EELS) has been further developed. This approach depends on quantifying subtle changes in the valence electron excitation spectrum as a function of composition. It involves determining the single-scattering intensities, calculating oscillator strengths, and applying multiple least squares fitting to reference spectra for water and organic constituents. The technique has now been extended to spectrum-imaging, so that two-dimensional water distributions can be obtained from hydrated cryosections. Automated processing of the spectrum-image data has been implemented, and ways of reducing the computation time are being investigated. Applications of the technique (e.g., analyzing the water content of rapidly-frozen hepatocytes and cryopreserved embryos) are in progress.