THEORY OF ANGULAR DEPENDENCE OF LIGHT SCATTERED BY BACTERIA AND SIMILAR-SIZED BIOLOGICAL OBJECTS
THEORY OF ANGULAR DEPENDENCE OF LIGHT SCATTERED BY BACTERIA AND SIMILAR-SIZED BIOLOGICAL OBJECTS
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DOI：
10.1016/0022-5193(68)90174-4
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发表时间：
1968-01-01
影响因子：
2
通讯作者：
KOCH, AL
中科院分区：
文献类型：
--
作者：
KOCH, AL
对于悬浮的随机取向，不对称的颗粒稍微不规则的形状，合理准确的估计光散射可以计算从简单的瑞利-甘斯理论，即使应用于大型物体，如哺乳动物线粒体或最研究的细菌，大肠杆菌。计算适用于直径小于1 [mu]的细长颗粒，长度为2至4倍，折射率平均小于周围介质的5%。简单的Rayleigh-Gans近似对于这些大颗粒非常有效，因为在计算光散射时，需要对取向、不对称性、形状的不均匀性和次要尺寸的变化进行平均。这些平均值倾向于最小化如果所有颗粒都是完美的球形并且具有相同的体积，则会发现的详细差异。在高角度的理论和实验测量之间的一个数量级的差异被解释为从颗粒的壁的高折射率或从细胞材料的不规则分布的光散射的结果。但是对于这些类型的生物材料，大部分光几乎是向前散射的;小角度光散射测量应该相当准确地得出颗粒的平均体积。
For suspension of randomly oriented, asymmetric particles of slightly irregular shape, reasonably accurate estimates of the light scattering can be computed from simple Rayleigh-Gans theory, even when applied to large objects such as mammalian mitochondria or the most-studied bacteria, Escherichia coli. The calculations apply for elongated particles of diameter less than 1 [mu], ranging from 2 to 4 times as long with an index of refraction averaging less than 5% greater than the surrounding medium. The simple Rayleigh-Gans approximation works quite well for these large particles because in computing the light scatter it is necessary to average over orientation, asymmetry, heterogeneity in shape, and variations in the minor dimension. These averages tend to minimize the detailed discrepancies that would be found if all particles were perfectly spherical and of the same volume. An order of magnitude discrepancy between the theory and experimental measurement at high angles is interpreted as resulting from the light scattering from the high index of refraction of the walls of the particles or from the irregular distribution of cell materials. But for these types of biological materials, most of the light is scattered in nearly the forward direction; and low angle light scattering measurements should yield quite accurately the average volume of the particles.