The effects of media properties on the horseradish peroxidase-catalyzed fluorogenic reaction

The effects of media properties including buffers, acidity, solvents and surfactant on horseradish peroxidase-catalyzed fluorogenic reaction were investigated. The results showed that the so-called non-fluorescent hydrogen donors were in fact fluorescent. There existed an acid—base equilibrium in the fluorescent dimer product. For p -hydroxyphenylpropionic acid, a pK_a value of 8.0 for the product was obtained from its titration curve. The product fluorescence increased with higher pH, however, a longer time was needed to reach the reaction equilibrium due to the pH mismatch problem. Cationic micelles cetyltrimethylammonium bromide and cetyltrimethylammonium chloride could reduce the pH mismatch and offered a way to further increase the determination sensitivity. Finally, a micelle-enhanced flow-injection analysis of horseradish peroxidase is suggested.     

Finite-element analysis of planar dielectric waveguide discontinuities

The finite element method is combined with the mode-matching method and the multi-mode network method to analyze the scattering and radiation characteristics of a class of planar dielectric waveguide discontinuities. Unlike the conventional method to treat the radiation as a source-field problem, in the present approach, the dispersion characteristics of dielectric guided-wave structures are calculated first, and then the radiation problem is transferred to the propagation problem of a series of surface-waves and space waves from the viewpoint of scattering, thus the analysis is tremendously simplified.     

烟草伤残苗超越补偿反应的生理测试初报

检测结果证明烟苗在遭到外力损伤情况下,其内部主要生理指标标如叶绿素含量、光合速率、可溶性糖含量和根活力等在伤残初期有不同程度的升高,表现出较为明显的超越补偿反应。但各指标升高幅度随时间而渐降,表时超越补偿反应具有一定的时效性。     

吸收比-系数倍率法及其应用——水杨酸钠、安替比林和咖啡因的同时测定

用吸收比－系数倍率法同时测定撒痛风注射液中水杨酸钠、安替比林和咖啡因三组分的含量。它们的回收率分别为１００．７％～１０２．１％、９５．９３％～１０４．５％和９７．５７％～１０１．７％。