光电子显微镜中的对比效应；生物表面成分的紫外线剂量依赖性量子产率。

Contrast effects in photoelectron microscopy; UV dose-dependent quantum yields of biological surface components.

作者信息

Griffith O H, Holmbo D L, Habliston D L, Nadakavukaren K K

出版信息

Ultramicroscopy. 1981;6(2):149-56. doi: 10.1016/0304-3991(81)90054-1.

Abstract

The relative brightness of photoelectron microscopy images as a function of exposure to UV light has been determined from model systems representative of biological cell surface components. Quantitative data for amino acid homopolymers, yields. The photoelectron quantum yields, increase substantially over the initial values. For example, the quantum yields fo poly-L-tyrosine at 200 nm is initially about 5 X 10(-8) electron/incident photon. The quantum yield increases with 254 nm irradiation, leveling off at about 5 X 10(-4) electrons/incident photon after a dose of 3 X 10(21) quanta cm-2. Pre-irradiation of poly-L-tyrosine in the presence of certain chemical agents, for example, the Lewis base diborane (B2H6), results in a substantial reduction of the dose-dependent increase in quantum yield. Exposure to the reducing agent stannane (SnH4) essentially eliminates the effect. These chemical treatments provide methods of controlling the UV dose-dependent effects in the photoelectron images.

摘要

已从代表生物细胞表面成分的模型系统中确定了光电子显微镜图像的相对亮度与紫外线照射量之间的函数关系。氨基酸均聚物的定量数据、产率。光电子量子产率比初始值大幅增加。例如，聚-L-酪氨酸在200 nm处的量子产率最初约为5×10⁻⁸电子/入射光子。量子产率随254 nm辐射而增加，在剂量为3×10²¹量子/cm²后稳定在约5×10⁻⁴电子/入射光子。在某些化学试剂（例如路易斯碱乙硼烷（B₂H₆））存在下对聚-L-酪氨酸进行预辐照，会导致量子产率随剂量增加的幅度大幅降低。暴露于还原剂锡烷（SnH₄）基本上消除了这种影响。这些化学处理提供了控制光电子图像中紫外线剂量依赖性效应的方法。