黄酮-6-羧酸类化合物的合成、表征和抑菌活性

通过查尔酮路线合成了6种黄酮-6-羧酸化合物,采用I2/DMSO为氧化剂通过微波辐射合成了其中3种黄酮羧酸.所有化合物的结构通过NMR,IR和元素分析方法进行了表征,并采用X射线单晶衍射法进一步测定了黄酮-6,4'-二羧酸的晶体结构.初步生物活性试验结果表明,6种化合物对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌均有一定的抑制作用.     

Dielectric analysis on phase transition and micelle shape of polyoxyethylene trisiloxane surfactant in dilute aqueous solution

The cloudy Silwet L-77 aqueous solution on the concentration range from 0.5%to 50%was investigated by dielectric relaxation spectroscopy.The concentration dependence of phase microstructure was confirmed by means of analyzing the dielectric parameters of bulk solution.The relaxation behavior was assigned to the interfacial polarization between the micelle and the medium,and the relaxation distribution parameter was used to figure the shape transition from sphere to ellipsoid with the concentration increasing.The synchronous reduction of permittivity and conductivity indicated the formation of the lamellar phase. As compensation,the quantity of the surfactant liquid phase gradually decreased,whose shape constantly kept ellipsoidal.     

微孔板发光二极管诱导荧光-表面活性剂增敏法测定盐酸小檗碱

研制了微孔板发光二极管诱导荧光分析仪,以发光二极管为激发光源,Y形光纤束传导激发光和荧光,采用平面型光敏二极管接收荧光.采用二维定位器移动微孔板,可实现对多个样品快速连续的测定.利用弱碱性介质中阴离子表面活性剂十二烷基苯磺酸钠(SDBS)对盐酸小檗碱荧光的增敏作用,在pH 9.0的Britton-Robinson缓冲溶...     

Synthesis and bioactivity of novel nitric oxide-releasing ursolic acid derivatives

A series of furoxan-based novel nitric oxide-donating ursolic acid(UA) derivatives(7a-f) were synthesized,and their cytotoxic activities against HepG2 cells in vitro were evaluated by MTT method.It was found that 7a-d and 7f showed more potent cytotoxic activities than control 5-fluorouracil and UA.     

First total synthesis of two new heterocyclic compounds:Bretschneiderazines A and B

Facile synthesis of the two new natural heterocyclic compounds bretschneiderazines A（2） and B（3）,isolated from an extract of the stems of Bretschneidera sinensis,is reported.We employed the cyclization reaction of benzamide by directed lithiation and sequential treatment with sulfur and phosgene as key steps.All new compounds have been fully characterized by means of IR,¹H NMR,¹³C NMR,and HRMS.     

Crystal structure and DNA binding studies of a cobalt(Ⅱ) complex containing mixed-ligands of 1,10-phenathroline and glycollic acid

A cobalt（11） complex containing mixed-ligands of 1,10-phenathroline（phen） and glycollic acid（GA）.|Co（GA）₂（phen）| was synthesized and its structure was characterized by X-ray diffraction.The interaction of the complex with DNA was investigated by electronic absorption spectra and electrochemical methods.Electronic absorption spectrum experiments showed that after interaction with DNA.the characteristic absorption peaks of |Co（GA）₂（phen）| underwent hypochromic effect as well as redshift. Also,the binding strength of 3.8×10⁴L/mol was estimated by titration method.Electrochemical assays revealed that the redox peak currents of the complex decreased obviously accompanied by a positive shift of the formal potential after association with DNA.All these results revealed that the synthesized cobalt complex bound with DNA via an intercalation mode.     

Application of the first collision source method to CSNS target station shielding calculation

Ray effects are an inherent problem of the discrete ordinates method. RAY3 D, a functional module of ARES, which is a discrete ordinates code system, employs a semi-analytic first collision source method to mitigate ray effects. This method decomposes the flux into uncollided and collided components, and then calculates them with an analytical method and discrete ordinates method respectively. In this article, RAY3 D is validated by the Kobayashi benchmarks and applied to the neutron beamline shielding problem of China Spallation Neutron Source(CSNS)target station. The numerical results of the Kobayashi benchmarks indicate that the solutions of DONTRAN3 D with RAY3 D agree well with the Monte Carlo solutions. The dose rate at the end of the neutron beamline is less than10.83 μSv/h in the CSNS target station neutron beamline shutter model. RAY3 D can effectively mitigate the ray effects and obtain relatively reasonable results.