Identification of metabolites of Danggui Buxue Tang in rat urine by liquid chromatography coupled with electrospray ionization time‐of‐flight mass spectrometry

A method coupling liquid chromatography with electrospray ionization time‐of‐flight mass spectrometry (LC/ESI‐TOF/MS) has been developed for rapid and sensitive analysis of rat urinary metabolite profile of Danggui Buxue Tang (DBT), a well‐known Chinese herbal formula. After oral administration of DBT, urine samples were collected during 0–24 h, and then pretreated by solid‐phase extraction. A total of 68 compounds including 13 parent compounds and 55 metabolites were detected in the drug‐containing urines compared with blank urines. The total analytical time was less than 20 min. Metabolites of DBT were identified using dynamic adjustment of the fragmentor voltage to produce structure‐relevant fragment ions. By using this approach, the mass accuracy of precursor and fragment ions was typically within ±5 ppm of the theoretical values, and enabled the identification of 43 metabolites including 27 isoflavanoid and 16 phthalide metabolites. Our results indicated that glucuronidation and sulfation were the major metabolic pathways of isoflavonoids, while glutathione conjugation, glucuronidation and sulfation were the main metabolic pathways of phthalides. No saponin‐related metabolites were detected. The results of the present study provided important structural information relating to the metabolism of DBT. Furthermore, this work demonstrated the potential of the LC/ESI‐TOF/MS approach for identification of metabolites from Chinese herbal medicines in urine. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of a water-soluble cationic chiral diamine ligand bearing a diguanidinium and application in asymmetric transfer hydrogenation

A novel water-soluble cationic N-monosulfonated chiral diamine ligand diguanidinium 1c was easily prepared from (R,R)-DPEN and its rhodium complex and was successfully applied in the asymmetric transfer hydrogenation of prochiral ketones and imines in water by using sodium formate and formic acid as co-hydrogen donors. Various substrates were reduced with high yields and good to excellent enantioselectivities (up to >99% ee).     

CO_2 Adducts of the Amino and Imino Groups Studied by ~1HNMR and ~(13)CNMR

When isolating 1,4-dideoxy-1,4-imino-D-arabinitol using Dowex 1(2 (OH- form) or CM-Sephadex C-25 (NH4+ form), we found another compound always accompanied with it. It was apparent that the two compounds had similar structures from their 1HNMR and 13CNMR in D2O (Fig. 1). At first, we guessed the two compounds were isomerides. But when acid was added into the solution of the two compounds, the signals for the minor compound disappeared.Figure 1 13CNMR of 1,4-dideoxy-1,4-imino-D-arabin…     

内陷在C_(60)中的氢原子的性质

在短程球形势阱的模型下 ,运用线性变分法并采用B 样条作为展开基函数计算了内陷于C60 几何中心的氢原子能谱和波函数 ,并计算了势阱深度对能谱的影响 ,详细讨论了内陷氢原子表现出的一系列特殊性质 ,从而对低维半导体材料性能的研究提供了有效的数据 ;同时这一工作也表明 ,用线性变分法结合B 样条函数在处理这类问题时是非常有效的。     

生产计划中阶梯型价格原料最优配置

按照规模经济效应,商品价格会随着订购量的增大而减小(即打折).根据生产实际,本文提出了商品的阶梯型价格,建立了最优生产计划模型.该计划模型有选择性地生产能够获最大利润的产品,并且可以对生产所需的原料进行最优配置;基于最优化理论与方法,给出了求解所建模型的有效算法,通过实例验证了算法的可行性和有效性.     

A new method for estimating bounds of eigenvalues

A new method for estimating the bounds of eigenvalues is presented. In order to show that the method proposed is as effective as Qiu's, an undamping spring-mass system with 5 nodes and 5 degrees of freedom is given. To illustrate that the present method can be applied to structures which cannot be treated by non-negative decomposition, a plane frame with 202 nodes and 357 beam elements is given. The results show that the present method is effective for estimating the bounds of eigenvalues and is more common than Qiu's. Project supported by the National Natural Science Foundation (No. 19872028) and the Mechanical Technology Development Foundation of China.     

The application with tetramethyl pyrazine for antithrombogenicity improvement on silk fibroin surface

Chuanxiongqin (tetramethyl pyrazine, TMPZ) is an active ingredient of the Chinese herb and was used to improve the anticoagulant activity of silk fibroin (SF). The side methyl of TMPZ was oxidized, and then linked to polyacrylic acid (PAA) via an ester bond. The prepared conjugate was further mixed with SF solutions at different ratios to make blend films. The resulting products were characterized by FTIR, UV spectrometer and X-ray photoelectron spectroscopy (XPS). The in vitro antithrombogenicity were evaluated by the activated partial thromboplastin time (APTT) and the prothrombin time (PT). It was shown that blend films had longer coagulation time than the pure SF film.     

超导芯截面形状对Bi-2223/Ag带Jc的影响

磁光图像显示Ｂｉ－２２２３／Ａｇ带材中单根超导芯的宽面两侧边缘分布有较大的超导电流密度，Ｂｉ－２２２３单根超导芯的横截面是纺锤形的，单位宽度上的横截面面积之比与电流密度在横截面上不同部分的分布之比相当，高的电流密度在单根超导芯两则的分布可能是由单芯横截面的形状引起的。     

Structural characterization and identification of C19‐ and C20‐diterpenoid alkaloids in roots of Aconitum carmichaeli by rapid‐resolution liquid chromatography coupled with time‐of‐flight mass spectrometry

Aconite alkaloids from the roots of Aconitum carmichaeli (Fuzi, in Chinese) have been investigated by rapid‐resolution liquid chromatography coupled with time‐of‐flight mass spectrometry (TOFMS) in positive mode. With dynamic adjustment of the key role as fragmentor voltage in TOFMS, an efficient transmission of the ions was achieved to obtain the best sensitivity for providing the molecular formula for each analyte, and abundant fragment ions for structural information. Fifteen authentic standards isolated from Fuzi with various structures were first characterized by TOFMS, including diester‐diterpenoid alkaloids (DDAs), monoester‐diterpenoid alkaloids (MDAs), alkylol amine‐diterpenoid alkaloids (ADAs), veatchine‐type alkaloids and atisine‐type alkaloids. Fragmentation rules and key diagnostic fragment ions have been summarized, and possible pathways of fragmentation have been proposed. By accurate mass measurements within 5 ppm error for each ion, 30 C₁₉‐diterpenoid alkaloids including 10 DDAs, 3 MDAs, 9 ADAs and 8 other type alkaloids, and 8 C₂₀‐diterpenoid alkaloids including 4 veatchine‐type alkaloids and 4 atisine‐type alkaloids could be identified in a methanolic extract of Fuzi. Some isomers of aconite alkaloids were also differentiated. Based on the differences between their fragmentation pathways and special fragment ions, each type of aconite alkaloids was differentiated. Copyright © 2009 John Wiley & Sons, Ltd.     

The slagging propensity of Zn-rich scrap tyre ash in reducing environments consisting of CO and CO2 and its promotion of the slagging of Si-rich coal ash

This study includes a comprehensive investigation on the ash slagging characteristics of zinc (Zn)-rich tyre ash and its interaction with silica (Si)-rich coal ash blended at different ratios in a 5% CO in CO₂ reducing environment. Such an environment is expected to occur near the burner in a combustor, as well as serves as a fundamental study on the slagging propensity upon the effect of CO, which is a principal reducing agent in a gasifier. An approach consisting of experimental studies using modified inclined plane (M-IP) methodology, advanced analytical techniques including the scanning electron microscopy (SEM) and x-ray photoelectron (XPS) spectroscopy, and thermodynamic equilibrium calculations were used to elaborate the slagging propensities of the single and blended ashes. Furthermore, the fate of Zn within tyre ash and its potential implications on the slagging properties were evaluated. Tyre ash easily melts to liquid slag upon increasing temperature compared to the silica-rich coal ash. Zinc does not evaporate but rather remains within tyre slag mostly as a hemimorphite (Zn₄(Si₂O₇)(OH))-like coordination structure attributing to the characteristic blue colour of tyre slag. The low ionic potential value of 2.7 for Zn²⁺ is characteristic of basic ions that have a greater tendency to depolymerise the Si-rich ash slag matrix and acts as a fluxing agent in ash slag. Moreover, it was proven that Zn²⁺ plays a synergistic role with Ca²⁺ in enhancing the flowability of the Si-rich slag remarkably. Furthermore, for the pure tyre slag, Zn was found to preferentially deposit at the corundum (Al₂O₃) substrate interface and even penetrate/react with the porous corundum, causing a strong corrosion on the substrate. However, blending of tyre ash with coal ash alleviates this problem by a preferred scavenging of Zn into the entire Si matrix, which in turn protects the corundum plate.