Experimental crushed granite column breakthrough curves, using 99Tc as spike tracer and 3H as invariant tracer, were analyzed by different linear regression techniques. Dispersity of crushed granite and the retardation factor of 99TcO4- on the crushed granite were determined simultaneously by one linear regression. Dispersity of crushed granite was also obtained with 3H as invariant tracer by the other linear regression. The dispersities found by spike source and invariant source methods are compared. Experimental results show that the dispersity found by the spike source method is close to that found by the invariant source method. This indicates that dispersity is only a characteristic of the dispersion medium.
The adsorption of 99Tc on the adsorbers Fe, Fe2O3 and Fe3O4 was studied by batch experiments under aerobic and anoxic conditions. The effects of pH and CO32- concentration of the simulated ground water on the adsorption ratios were also investigated, and the valences of Tc in solution after the adsorption equilibrium were studied by solvent extraction. The adsorption isotherms of TcO4- on the adsorbers Fe, Fe2O3 and Fe3O4 were determined. Experimental results have shown that the adsorption ratio of Tc on Fe decreases with the increase of pH in the range of 5-12 and increases with the decrease of the CO32- concentration in the range of 10-8M-10-2M. Under aerobic conditions, the adsorption ratios of 99Tc on Fe2O3 and Fe3O4 were not influenced by pH and CO32-concentration. When Fe was used as adsorbent, Tc existed mainly in the form of Tc(IV) after equilibrium and in the form of Tc(VII) when the adsorbent was Fe2O3 or Fe3O4 under aerobic conditions. The adsorption ratios of Tc on Fe, Fe2O3 and Fe3O4 decreased with the increase of pH in the range of 5-12 and increased with the decrease of the CO32- concentration in the range of 10-8M-10-2M under anoxic conditions. Tc existed mainly in the form of Tc(IV) after equilibrium when Fe, Fe2O3 and Fe3O4 was the adsorbent under anoxic conditions. The adsorption isotherms of TcO4- on the adsorbers Fe, Fe2O3 and Fe3O4 are fairly in agreement with the Freundlich’s equation under both aerobic and anoxic conditions.
Authors:Z. Cheng, Q. Lin, X. Jin, F. Wang, H. Bai, D. Chen, H. Fan, and J. Du
DTPA-Octreotide(Pentetreotide), a somatostatin analogue which can bind specifically and with high affinity to somatostatin
receptor in vitro and vivo, labeled with99mTc by tin reduction in acetate buffer, has been characterized by Reverse-phase High performance Liquid Chromatography. The
effect of different solvents, mobile phase pH, linear gradient and the injected volume on the separation efficiency was evaluated.
The results show that the separation efficiency is best using μBondapak-C18 (300×3.9 mm2), linear gradient of 40% to 80% methanol (1.0 ml/min) in 0.05M acetate buffer (pH 5.5) over a 30 min period and maintaining
for another 10 min. The labeled product is a mixture which mainly consists of five components (a, b, c, d, e) successfully
proved by HPLC. Paper chromatography is also evaluated in this paper. It may be used to determine the radiochemical purity
of the labeling product, but is not a good choice for the verification each components.
Authors:X. H. Fan, H. J. He, J. Wang, C. Y. Xu, and K. v. Gadow
The geographical patterns of tree species richness in forest communities have been studied widely, but little is known about the geographical variation of the estimated species richness and minimum areas using species-area curves. A differential technique based on the species-area relationships (SAR) was developed for estimating the minimum area (Amin) capturing 60- 80% of the species in each plot, which is an important characteristic of a forest community. The relationship between estimated species richness (ESR) from the SAR and the corresponding minimum area is described by the linear model ESR = 0.0051×Amin (R2 = 0.98, p < 0.0001). Both the ESR and the minimum area exhibit similar geographical variations with a significant increase along altitudinal and a decrease along latitudinal gradients. The spatial variations of the ESR were partitioned into three geographical components and their combined effects. Altitude accounted for 40% and 45% of the total variation in the ESR and the minimum area, respectively. While latitude accounted for 69% and 61% of the total variation in the ESR and the minimum area, respectively. Thus, latitude is the main determinant which influences the geographical variation of the ESR. As far as we know, this study presents the first report of the geographical patterns of the minimum area in temperate forests.
Authors:H. Yang, Hua Yin, Z. Wang, L. Fan, Q. Li, and X. Zhu
Traditional Chinese medicine (TCM) has been widely used in many countries for thousands of years and played an indispensable role in the prevention and treatment of diseases, especially the complicated and chronic ones. However, the application of TCM in diseases is still not fully recognized by people around the world, the main reason is that Chinese herb is a very complex mixture containing hundreds of different components. Thus, it is essential to make quality control and evaluation of TCM. A new quality evaluation method, quantitative analysis of multi-components by single marker (QAMS), was developed to the quality control of alkaloids in TCM, a case study on Radix aconiti lateralis, named Fuzi in Chinese. Six alkaloids, including aconitine, hypaconitine, mesaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, were selected as main components to evaluate the quality of Radix aconiti lateralis. The feasibility and accuracy of QAMS were checked by the external standard method, and various high-performance liquid chromatographic instruments and chromatographic conditions were investigated to verify its applicability. Using aconitine as the internal reference substance and the content of aconitine was calculated according to relative correction factors by high-performance liquid chromatography. The present results showed that there was no significant difference observed between the QAMS method and the external standard method with the relative average deviations less than 3.0%, and QAMS is an effective way to control the quality of herbal medicines and seems to be a convenient and accurate approach to analyze multi-composition when reference substances are unavailable.
Authors:A. He, M. Ye, Z. Tang, S. Lu, H. Cao, Y. Gu, X. Fan, L. Zhao, and J. Gao
The recombination of hydrogen and oxygen in technical gaseous waste of nuclear power plants has been studied. A highly efficient catalyst for reacting H2 with O2 to form water was prepared. Various operating conditions and factors affecting the recombination of H2 and O2 were tested and the best conditions were determined. Results show that the Pd–Al2O3 catalyst prepared had very good characteristics. The recombination rate of H2 and O2 was higher than 98.3% and 99.9%, respectively. After recombination, residual concentrations of H2 and O2 in waste gas were O2<3 ppm, H2<400 ppm. The Pd–Al2O3 catalyst and operating conditions determined for gaseous waste processing of nuclear power plants were satisfactory.