Comparative study of hollow-fiber liquid-phase micro-extraction and an aqueous two-phase system for determination of phytohormones in soil

Two methods, hollow-fiber liquid-phase micro-extraction (HF-LPME) and an aqueous two-phase system (ATPS), have been systematically optimized and compared for extraction and determination of phytohormones in soil by high-performance liquid chromatography (HPLC). The effects on extraction of conditions including solvent type and volume, extraction time, temperature, and amount of salt were evaluated. It was shown that ATPS was superior to HF-LPME for determination of paclobutrazol and uniconazole under the optimum conditions. The limits of detection (LODs) of ATPS were 0.002 μg g(-1) for uniconazole and 0.01 μg g(-1) for paclobutrazol, whereas LODs of HF-LPME were 0.005 μg g(-1) and 0.03 μg g(-1), respectively. Relative standard deviations (RSDs, n=5) and recovery were in the range 1.7-5.3 % and 86-102 %, respectively, for ATPS and 6.7-7.9 % and 40-60 % for HF-LPME. In addition, the advantages of ATPS were shorter extraction time, suitable for simultaneous pretreatment of batches of samples, and higher extraction capacity. ATPS was therefore applied to the determination of paclobutrazol and uniconazole in real soil samples. Uniconazole was detected in all the samples analyzed whereas paclobutrazol was not found.     

A new anti-diabetic sesquiterpenoid from Acorus calamus

A new sesquiterpenoid,1β,5α-guaiane-4β,10α-diol-6-one(1),was isolated from 70%EtOH extract of the rhizomes of Acorus calamus.The structure was determined on spectroscopic methods,especially 2D NMR techniques.The absolute configuration of 1 was confirmed by TDDFT quantum chemical calculation of its ECD spectrum.Compound 1 showed promising anti-diabetic activity on a insulin-mediated glucose consumption model of HepG2 cells.     

Synthesis and biological evaluation of new ligustrazine derivatives as anti-tumor agents

To discover new anti-cancer agents with multi-effect and low toxicity, a series of ligustrazine derivatives were synthesized using several effective anti-tumor ingredients of Shiquandabu Wan as starting materials. Our idea was enlightened by the "combination principle" in drug discovery. The ligustrazine derivatives' anti-tumor activities were evaluated on the HCT-8, Bel-7402, BGC-823, A-549 and A2780 human cancer cell lines. In addition the angiogenesis activities were valued by the chick chorioallantoic membrane (CAM) assay. 1,7-bis(4-(3,5,6-Trimethylpyrazin-2-yl)-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (4) and 3 α,12 α-dihydroxy-5β-dholanic acid-3,5,6-trimethylpyrazin-2-methyl ester (5) not only displayed antiproliferative activities on these cancer cells, but also dramatically suppressed normal angiogenesis in CAM. The LD?? value of the compound 5 exceeded 3.0 g/kg by oral administration in mice.     

A Dye-sensitized Nanocrystalline Solid State Photovoltaic Cell

Dye-sensitized photovoltaic cells based on nanocrystalline TiO, film are of considerabletechnological interest because of their high conversion efficiency and potential low cost.However the liquid junction photovoltaic cells have a series of technological problems inpractical applications. Recently, the replacement of liquid electrolyte by solid stateconductors such as ionic conducting polymers' and organic hole tfansport materialsZ hasbeen tested. In this papef, we report the fabrication of …     

电沉积制备钯铂电极上乙醇的电催化氧化

研究了乙醇在碱性介质（１．０ｍｏｌ·Ｌ－１ＮａＯＨ）中电沉积制备的Ｐｄ／ＧＣ、Ｐｔ／ＧＣ和Ｐｄ．Ｐｔ／ＧＣ电极上的电催化氧化．实验结果表明：由此法制备的钯铂系列合金电极对乙醇的电催化氧化表现出明显的协同效应─—乙醇在含把原子分数ｙｐｂ＝０．３３６的Ｐｄ－Ｐｔ／ＧＣ合金电极上的阳极交换电流密度是其在纯铂电极上的３０多倍．     

Modulational instability of incoherently coupled beams in azobenzene-containing polymer with photoisomerization nonlinearity

The modulational instability of two incoherently coupled beams in azobenzene-containing polymer with photoisomerization nonlinearity is investigated analytically and numerically. Our results show that as a precursor to spatial optical soliton formation, modulational instability can be adjusted and controlled by the wavelength combinations of the signal and background beams. We also discuss the dependences of strength of modulational instability on intensities of two signal beams and background beam. These findings make it possible to predict the formation of incoherently coupled soliton pairs in azobenzene-containing polymer.     

Internal mode of incoherent photovoltaic vector solitons

The internal modes of incoherent vector solitons (IVSs) in photovoltaic photorefractive materials are investigated in the framework of coupled nonlinear Schr\"{o}dinger equations. It is found that there is a pair of internal modes corresponding to a bright--bright IVS. The propagation dynamics of the bright-bright IVS perturbed by the internal modes is simulated by numerical method.     

银盘电极交流示波计时电位法及其机理的研究

示波分析中 ,电极的种类和预处理的好坏直接影响示波分析的范围和结果 ,常用的汞膜电极的灵敏度较低 ,限制了其应用 .因此 ,开发新电极是示波分析发展的一个重要途径 .银是一种较好的电极材料 ,具有制备简单、无汞污染等优点 ,以它为工作电极利用阴极溶出 [1,2 ] 和阳极溶出 [3] 进行测定的灵敏度较高 .冶保献等 [4 ]报道了血红蛋白在普通银电极上能进行直接电子传递 ,并对银基的特异功能引起关注 .本文对银盘电极的示波计时电位法及其机理进行了研究 .与用汞膜电极的示波计时电位法相比 ,可使检测下限降低 2～ 3个数量级 ,有望成为痕量分析…     

β-环糊精用于铜的二次微分简易示波伏安法测定

示波分析;硅黄铜;β-环糊精用于铜的二次微分简易示波伏安法测定     

Design,Synthesis, and In Vitro and In Vivo Antifungal Activity of Novel Triazoles Containing Phenylethynyl Pyrazole Side Chains

A series of triazole derivatives containing phenylethynyl pyrazole moiety as side chain were designed, synthesized, and most of them exhibited good in vitro antifungal activities. Especially, compounds 5k and 6c showed excellent in vitro activities against C. albicans (MIC = 0.125, 0.0625 μg/mL), C. neoformans (MIC = 0.125, 0.0625 μg/mL), and A. fumigatus (MIC = 8.0, 4.0 μg/mL). Compound 6c also exerted superior activity to compound 5k and fluconazole in inhibiting hyphae growth of C. albicans and inhibiting drug-resistant strains of C. albicans, and it could reduce fungal burdens in mice kidney at a dosage of 1.0 mg/kg. An in vivo efficacy evaluation indicated that 6c could effectively protect mice models from C. albicans infection at doses of 0.5, 1.0, and 2.0 mg/kg. These results suggested that compound 6c deserves further investigation.