Interaction of the main components from the traditional Chinese drug pair Chaihu-Shaoyao based on rat intestinal absorption

The Chaihu-Shaoyao drug pair (Bupleuri Radix and Paeoniae Radix Alba) which is a traditional Chinese drug pair, has been widely used for anti-inflammatory purposes. Saikosaponin a (SSA), saikosaponin d (SSD) and paeoniflorin are identified as the main components in the pair. The present study focused on the interaction of the main components based on investigating their intestinal absorption using a four-site perfused rat intestinal model in order to clarify the mechanism of the compatibility of Chaihu-Shaoyao. The concentrations of SSA, SSD and paeoniflorin in the intestinal perfusate were determined by LC/MS or UPLC (Ultra Performance Liquid Chromatography) methods, followed by P*(eff) (effective permeability) and 10% ABS (the percent absorption of 10 cm of intestine) calculations. The results showed that all of the three main components displayed very low permeabilities (P*(eff) < 0.4), which implied their poor absorption in the rat intestine. The absorption levels of SSA and SSD were similar in intestine and higher in ileum than those in other intestinal regions in the decreasing order: colon, jejunum and duodenum. However, there is no significant difference in the absorption of paeoniflorin in the four segments (P < 0.05). The P*(eff) values of paeoniflorin exhibited an almost 2.11-fold or 1.90-fold increase in ileum when it was co-administrated with SSA and SSD, as well as 2.42-, 2.18-fold increase in colon, respectively, whereas the absorptions of SSA and SSD were not influenced by paeoniflorin. In conclusion, SSA and SSD could promote the absorption of paeoniflorin. To some extent this might explain the nature of the compatibility mechanisms of composite formulae in TCMs.     

Electrochemical preparation and magnetic properties of submicron Co x Pb1−x dendrites

Magnetic dendrites of Co _x Pb_1−x were fabricated through potentiostatic electrochemical deposition on Cu substrates in boric acid solution at room temperature. The as-deposited dendrites were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), electrodeposition (ED), and energy dispersive X-ray spectroscopy (EDS). SEM results indicate that the Co _x Pb_1−x dendrites are highly symmetrical in structures. The diameters of the branches are about 50 ~ 200 nm, and the backbones are continuous with lengths up to about 10 μm. XRD patterns show that the as-deposited dendrites are solid solutions. The annealing treatment can result in the recrystallization of these metastable alloys into two separate phases. TEM, ED, and EDS results also reveal that the backbones and the branches of the dendrites are composed of different amounts of cobalt. Magnetic measurements confirm that the as-deposited Co _x Pb_1−x dendrites have a softly ferromagnetic behavior, and a small coercive force (about 80 Oe). Also the saturation magnetizations of the Co _x Pb_1−x dendrites decrease rapidly with the temperature increasing.     

The kinetics of CO pathway in methanol oxidation at Pt electrodes, a quantitative study by ATR-FTIR spectroscopy

Methanol (MeOH) oxidation reaction (MOR) at Pt electrodes under potentiostatic conditions has been investigated by electrochemical in situ FTIR spectroscopy (FTIRS) in attenuated-total-reflection configuration under controlled flow conditions in 0.1 M HClO(4) with 2 M MeOH, where the mass transport effects are largely eliminated using a flow cell. Our results reveal that (i) at constant potentials, the methanol dehydrogenation rate decreases while the CO(ad) oxidation rate increases with the accumulation of CO(ad) until the maximum CO(ad) coverage (ca. 0.5 ML i.e., the steady state) is reached; (ii) at fixed CO(ad) coverage, the rates for MeOH decomposition to CO(ad) and CO(ad) oxidation increases with potential from 0.3 to 0.7 V (vs. RHE), with Tafel slopes for MeOH dehydrogenation of ca. 440 ± 30 mV/dec, which is independent of CO(ad) coverage; (iii) the current efficiency of the CO pathway in MOR at 0.6 and 0.7 V is below 20% and it decreases toward higher potentials. The mechanisms as well as the potential induced change in the kinetics of different pathways involved in MOR are briefly discussed.     

Reactions of Ruthenium–Allenylidene Complexes Tethering a Cyclopropyl Group

Two cyclopropyl allenylidene complexes [Ru]=CCC(R)(C₃H₅) ([Ru]=[RuCp(PPh₃)₂], Cp=Cyclopentadienyl; R=thiophene ( 2a ) and R=Ph ( 2b )) are prepared from the reactions of [Ru]Cl with the corresponding 1‐cyclopropyl‐2‐propyn‐1‐ol in the presence of KPF₆. Thermal treatment, halide‐anion addition, and palladium‐catalyzed reactions of 2a and 2b all lead to a ring expansion of the cyclopropyl group, giving the vinylidene complexes 4a and 4b , respectively, each with a five‐membered ring. This ring expansion proceeds by C C bond formation between Cβ of the cumulative double bond and a methylene group of the cyclopropyl ring. In the reaction of 2a with pyrrole, consecutive formation of two C C bonds, one between C‐2 of pyrrole and Cγ of 2a and the other between C‐3 of pyrrole and Cα, results in the formation of 6a . The reaction proceeds by addition of pyrrole and 1,3‐proton shifts. The hydrogenation of 2a by NaBH₄ is carried out in different solvents. The cumulative double bonds are reduced regioselectively to give a mixture of 7a and 8a . Interestingly, use of different solvents leads to different ratios of 7a and 8a . Presence of a protic solvent like methanol in dichloromethane or chloroform solution increases the yield of 8a , thus revealing that both the rates of hydroboration and deboronation increase. The structures of two new complexes 4a and 6a have been firmly established by X‐ray diffraction analysis.     

Poly[tetra‐μ2‐l‐lactato‐indium(III)sodium(I)]

The asymmetric unit of the title compound, [InNa(C₃H₅O₃)₄]_n, consists of one In^III ion, one Na^I ion and four crystallographically independent l ‐lactate monoanions. The coordination of the In^III ion is composed of five carboxylate O and two hydroxy O atoms in a distorted pentagonal–bipyramidal coordination geometry. The Na^I ion is six‐coordinated by four carboxylate O atoms and two hydroxy O atoms from four l ‐lactate ligands in a distorted octahedral geometry. Each In^III ion is coordinated by four surrounding l ‐lactate ligands to form an [In(l ‐lactate)₄]⁻ unit, which is further linked by Na^I ions through Na—O bonds to give a two‐dimensional layered structure. Hydrogen bonds between the hydroxy groups and carboxylate O atoms are observed between neighbouring layers.     

随机参数超空泡射弹弹道随机特性分析

超空泡射弹的发射装置及射弹在制造,安装过程中存在各种不确定性.本文采用最大熵法来分析这些不确定性对射弹弹道的影响.介绍了超空泡射弹的动力学模型,对射弹的受力特性和随机参数进行了分析.根据给出的理论编制了基于最大熵法的随机参数超空泡射弹弹道随机特性分析的仿真程序,并对一个模型弹仿真计算.计算表明,与发射装置有关的随机参数...     

关于迭代数列的审敛法

从迭代数列及其基本性质出发,给出单调有界定理、压缩映象原理、Cauchy收敛准则和上(下)极限四种判别迭代数列收敛的方法.     

Morita contexts and Galois theory for weak Hopf comodulelike algebras

We investigate the Morita context and graded cases for weak group corings and derive some equivalent conditions for μ to be surjective. Furthermore, we develop Galois theory for weak group corings. As an application, we give Galois theory for comodulelike algebras over a weak Hopf group coalgebra.     

Joint Reducing Subspaces of Multiplication Operators and Weight of Multi-variable Bergman Spaces

This paper mainly concerns a tuple of multiplication operators defined on the weighted and unweighted multi-variable Bergman spaces, their joint reducing subspaces and the von Neumann algebra generated by the orthogonal projections onto these subspaces. It is found that the weights play an important role in the structures of lattices of joint reducing subspaces and of associated von Neumann algebras. Also, a class of special weights is taken into account. Under a mild condition it is proved that if those multiplication operators are defined by the same symbols, then the corresponding von Neumann algebras are $*$-isomorphic to the one defined on the unweighted Bergman space.     

泡沫金属夹芯梁在重复冲击下的动态响应

为了研究重复冲击载荷作用下泡沫金属夹芯梁的动态响应,采用Abaqus数值仿真软件,基于可压碎泡沫模型（crushable foam）,建立了泡沫金属夹芯梁遭受楔形质量块冲击的有限元模型。通过将仿真获得的夹芯梁上下面板最终挠度与重复冲击实验结果进行对比,验证仿真方法的准确性。在此基础之上,分析了泡沫金属夹芯梁在楔形质量块重复冲击作用下的变形模式、加卸载过程以及能量耗散特性。结果表明,在重复冲击载荷作用下,夹芯梁的变形不断累积,上面板主要出现局部凹陷和整体弯曲,而芯层则是局部压缩,下面板表现为整体弯曲。在重复加卸载过程中,加卸载刚度随着冲击次数的增加而增大。随着冲击次数的增加,上面板和芯层的能量吸收增量不断减小,而下面板的能量吸收增量不断增加,且最终均趋于稳定。泡沫金属夹芯梁的塑性变形能增量不断减小,而回弹系数随着冲击次数逐渐增加,最后趋于稳定值。