Equilibrium constant for calcium ion and ascorbate ion

The combination of calcium and ascorbic acid in water at 25 degrees C has been examined by measuring the change of free calcium ion concentration as ascorbate was added in small increment to a solution of calcium. The data show clearly that complex formation between calcium ion and ascorbate ion occurred. At ionic strength mu = 0.1-0.2, the equilibrium constant of Ca++ and the singly-charged ascorbate ion has been measured to be 2.1 M-1. The precision of the result is better than 5% and the accuracy is estimated to be better than 20%. The application of the equilibrium constants is discussed.     

植物激素吲哚乙酸的夹心酶联免疫测定法

根据夹心法原理,初步建立了植物激素吲哚乙酸的酶联免疫测定法。在这个方法中,抗体最适包被浓度为20μg/ml。辣根过氧化物酶与抗体的结合物的最适稀释度为1:1000。4％聚乙二醇6000极大地改善了标准曲线,检测范围在每孔1.0至32ng。其它植物激素如脱落酸,吲哚丁酸与抗体的交叉反应很小。对植物材料中吲哚乙酸的含量进行了测定,并与其它作者用别的方法所得结果进行了比较。     

Weighting and selection of variables for cluster analysis

One of the thorniest aspects of cluster analysis continues to be the weighting and selection of variables. This paper reports on the performance of nine methods on eight leading case simulated and real sets of data. The results demonstrate shortcomings of weighting based on the standard deviation or range as well as other more complex schemes in the literature. Weighting schemes based upon carefully chosen estimates of within-cluster and between-cluster variability are generally more effective. These estimates do not require knowledge of the cluster structure. Additional research is essential: worry-free approaches do not yet exist.     

Inhibition of in vitro RNA synthesis by hycanthone, oxamniquine and praziquantel.

The schistosomicides, hycanthone, oxamniquine and praziquantel, were found to inhibit the in vitro RNA synthesis using isolated hamster liver nuclei. Preincubation of the nuclei with these drugs revealed that the inhibitory effect of oxamniquine was irreversible and progressed with time, whereas that of hycanthone and praziquantel was reversible. On the other hand, hycanthone and praziquantel have a high affinity for DNA but oxamniquine does not. The data indicate that the mechanism of inhibition by oxamniquine is different from that of hycanthone and praziquantel.     

Equilibrium constant for calcium ion and ascorbate ion

Summary The combination of calcium and ascorbic acid in water at 25°C has been examined by measuring the change of free calcium ion concentration as ascorbate was added in small increment to a solution of calcium. The data show clearly that complex formation between calcium ion and ascorbate ion occurred. At ionic strength =0.1–0.2, the equilibrium constant of Ca⁺⁺ and the singly-charged ascorbate ion has been measured to be 2.1 M^–1. The precision of the result is better than 5% and the accuracy is estimated to be better than 20%. The application of the equilibrium constants is discussed.     

Inhibition of in vitro RNA synthesis by hycanthone,oxamniquine and praziquantel

Summary The schistosomicides, hycanthone, oxamniquine and praziquantel, were found to inhibit the in vitro RNA synthesis using isolated hamster liver nuclei. Preincubation of the nuclei with these drugs revealed that the inhibitory effect of oxamniquine was irreversible and progressed with time, whereas that of hycanthone and parziquantel was reversible. On the other hand, hycanthone and praziquantel have a high affinity for DNA but oxamniquine does not. The data indicate that the mechanism of inhibition by oxamniquine is different from that of hycanthone and praziquantel.     

Matrix Suction of Unsaturated Colluvium Slope Influenced by Rainfall and Plant Condition： A Case of Taiwan Huafan University

This study investigates the variation of matrix suction,water content and ground water level before and after the rainfall for the unsaturated colluvium slope in the campus of Fuafan Uni-versity. The measuring devices including electrical matrix suction,water content and ground water level were set up in different sur-face of planting condition for each depth in real-time. It is ob-served that the matrix suction in the time from July to September is higher;however,when heavy rains caused by typhoon happened,matrix suction will drop rapidly. This variation is obvious in short grass zone and less clear in the broadleaf tree zone. The maximum value in short grass zone,long grass zone and broadleaf tree zone at 2 m depth are 90.3,68.2,18.5 kPa,respectively. These results are expected to serve as a reference for the study of slope stability mechanisms.