Two new eupodienone lignans from Gymnotheca chinensis

Two new eupodienone lignans, named gymnothelignan T(1) and gymnothelignan U(2) were isolated from the whole plants of endemicmedicinal plant of Gymnotheca chinensis(Saururaceae). The structures of the new compounds were elucidated by means of HRMS, 1D and 2D NMR. Compound 1 was tested for cytotoxic activity in HCT15, HCT116, A549, MCF-7 and HepG2 cells and exhibited no appreciable activity against these tested cell lines with IC50 values above 50 mmol/L.     

原子吸收光谱法测定磷酸酯化梨渣吸附的Cr（Ⅵ）离子

通过原子吸收光谱法研究了在不同pH值、吸附剂量、吸附质浓度和吸附时间条件下磷酸酯化改性梨渣吸附Cr（Ⅵ）离子的效果。溶液初始pH 4.5时,Cr（Ⅵ）离子的吸附达到最大值;酯化梨渣≥10g.L-1能除去Cr（Ⅵ）为100μg.L-1溶液中的86.5%的Cr（Ⅵ）离子。酯化梨渣对Cr（Ⅵ）离子的吸附符合Langmuir等温模型,其最大吸附能力为67.56μg.g-1。Cr（Ⅵ）离子达到吸附平衡的时间为90min,准一级反应动力学方程可描述酯化梨渣对Cr（Ⅵ）离子的吸附过程。     

Two novel polycyclic spiro lignans from Gymnotheca involucrata

Two novel lignans, gymnothespirolignans A (1) and B (2), possessing a rare polycyclic spiro skeleton, were isolated from the endemic plant of Gymnotheca involucrata Pei. Their structures were determined by spectroscopic evidences and the absolute configurations were confirmed by single crystal X-ray diffraction analysis. Compounds 1 and 2 showed promising antiviral activities against RSV with an IC₅₀ value of 31.87 and 17.51 μM, respectively.     

An experimental design approach using response surface techniques to obtain optimal liquid chromatography and mass spectrometry conditions to determine the alkaloids in Meconopsi species

A statistic approach using response surface methodology (RSM) for optimization of the ultra-high performance liquid chromatography (UHPLC) gradient and ionization response of electrospray ionization mass spectrometry (ESI-MS) to analyze the main alkaloids from the plant matrices of six Meconopsi species is presented. The optimization was performed with Box–Behnken designs (BBD) and the multicriteria response variables were described using global Derringer's desirability. Four parameters of UHPLC and six major parameters of ESI-MS were investigated for their contribution to analytes separation and response, leading to a total of 27 and 54 experiments being performed for each instrument, respectively. Quantitative analysis of four main alkaloids in nine samples from six Meconopsis species was employed to evaluate the statistical significance of the parameters on UHPLC–QTOF/ESI-MS analytes response. The results indicated that the optimized UHPLC–QTOF-MS method is very sensitive with the limit of detections (LODs) ranging from 0.5 to 0.1 ng/ml. The overall intra-day and the inter-day variations were less than 2.45%. The recovery of the method was in the range of 94.3–104.8% with RSD less than 4.0%. This approach has important implication in sensitivity enhancement of the ultra-trace determination of alkaloids from complex matrixes in the fields of natural products, metabolomics and pharmacokinetics.     

Two new cyclic diarylheptanoids from the stems of Ostryopsis nobilis

Two new cyclic diarylheptanoids named ostryopsitrienol(1) and ostryopsitriol(2),together with six known compounds,were isolated from the stems of endemic medicinal plant of Ostryopsis nobilis (Betulaceae).The structures of the new compounds were elucidated by means of HRMS,~1D NMR,~2D NMR and X-ray crystallography analysis.     

Attractive target wave patterns in complex networks consisting of excitable nodes

This review describes the investigations of oscillatory complex networks consisting of excitable nodes,focusing on the target wave patterns or say the target wave attractors.A method of dominant phase advanced driving(DPAD) is introduced to reveal the dynamic structures in the networks supporting oscillations,such as the oscillation sources and the main excitation propagation paths from the sources to the whole networks.The target center nodes and their drivers are regarded as the key nodes which can completely determine the corresponding target wave patterns.Therefore,the center(say node A) and its driver(say node B) of a target wave can be used as a label,(A,B),of the given target pattern.The label can give a clue to conveniently retrieve,suppress,and control the target waves.Statistical investigations,both theoretically from the label analysis and numerically from direct simulations of network dynamics,show that there exist huge numbers of target wave attractors in excitable complex networks if the system size is large,and all these attractors can be labeled and easily controlled based on the information given by the labels.The possible applications of the physical ideas and the mathematical methods about multiplicity and labelability of attractors to memory problems of neural networks are briefly discussed.     

Network dynamics and its relationships to topology and coupling structure in excitable complex networks

All dynamic complex networks have two important aspects, pattern dynamics and network topology. Discovering different types of pattern dynamics and exploring how these dynamics depend or/network topologies are tasks of both great theoretical importance and broad practical significance. In this paper we study the oscillatory behaviors of excitable complex networks （ECNs） and find some interesting dynamic behaviors of ECNs in oscillatory probability, the multiplicity of oscillatory attractors, period distribution, and different types of oscillatory patterns （e.g., periodic, quasiperiodic, and chaotic）. In these aspects, we further explore strikingly sharp differences among network dynamics induced by different topologies （random or scale-free topologies） and different interaction structures （symmetric or asymmetric couplings）. The mechanisms behind these differences are explained physically.     

氯化钠存在下丙醇-碘化钾体系萃取分离铂、钯的研究

研究了氯化钠存在下丙醇－碘化钾体系对铂（Ⅱ）、钯（Ⅱ）萃取行为及体系在盐酸介质中的分相条件。在盐酸介质中,体系可同时萃取铂（Ⅱ）、钯（Ⅱ）,萃取率分别为99．8％、99．4％,方法可用于从贱金属中分离铂、铯 。对阳极泥、砂铂矿、废催化剂样品中的铂、钯进行了分离,分析结果与其它方法相符,并对萃取机理也进行了探讨。     

低同源性蛋白质结构预测

基因组计划在实施产生了大量的DNA序列信息,如何有效地利用这些信息来研究基因的产物－蛋白质的结构与功能成为引入注目的研究领域,同源蛋白质结构预测及蛋白质折工识别是在基因组水平上进行蛋白质结构预测的有效方法,酵母基因组中约有50％的基因可以通过这类方法来确定其表面产物蛋白质的结构[1],但是目前所采用的方法在低同源性蛋白质的结构预测方面尚存在较大困难。