Two new triterpenes from Duchesnea indica

Two new triterpenes,2α,3β-dihydroxyurs-12-en-18,19-epoxy-28-oic acid(1)and 18,19-seco,2α,3α-dihydroxyl-19-oxo-urs-11, 13(18)-dien-28-oic acid(2)were isolated from the herbaceous part of Duchesnea indica.Their structures were elucidated by spectroscopic analysis,including 2D NMR technique.The isolated compounds exhibited moderate cytotoxic activities against HeLa and L929 cell lines.     

Analysis of the hyper-chaos generated from Chen’s system

This letter does some further researches on a newly proposed hyper-chaos found in [Gao TG, Chen ZQ, Chen G. A hyper-chaos Generated from Chen’s system, Int J Mod Phys C 2006;17(4):471–8], and gets some new results with some parameters of the system are definite and the other one varies. The basic dynamical behavior of the system under various conditions is analyzed, and the new findings is not only demonstrated by computer simulations but also verified with bifurcation analysis.     

Synthesis,Characterization and Application of Organic-inorganic Hybrid and Carbaryl-imprinted Capillary Monolithic Column

Organic-inorganic hybrid and carbaryl-imprinted capillary monolith was synthesized via methacrylic acid（MAA） as functional monomer, γ-methacryloxypropyltrimethoxysilane（γ-MAPS） as crosslinker and carbaryl as template molecule in an acetonitrile/dichloromethane mixture（1：4, volume ratio）. With the capillary column obtained from this monolith, three carbamates（carbaryl, fenobucarb and metolcarb） were separated effectively by electrochromatography with the kMIp/kNlP values of 7.57, 1.27 and 1.64, respectively. In 20 mmol/L phosphate buffer solution（pH=3.5） with 30%（volume fraction） of acetonitrile, carbaryl was separated directly from the three-carbamate mixture（carbaryl, fenobucarb and metolcarb） with an effective 15 cm-length imprinted column.     

壳聚糖基多功能纳米药物载体的体外研究

制备了一种壳聚糖基多功能纳米药物载体系统, 并探讨了其体外释药性质. 合成了甲氨蝶呤-壳聚糖偶联物(MTX-CS), 甲氨喋呤(MTX)的取代度为6.3%; MTX-CS具有两亲性, 在水性介质中能自组装形成纳米粒子, 平均粒径为(269.5±18.3) nm, zeta电位为(25.7±0.9) mV. MTX-CS纳米粒子能有效包载抗血管生成药Combretastatin A-4(CA-4), 当药物/载体材料投料比为1∶4 时, 载药量为15.7%, 包封率为62.8%. 体外释放实验结果显示, CA-4释放较快, MTX释放缓慢, 有利于发挥2种药物的协同抗肿瘤作用.     

Removing paint from a metal substrate using a flattened top laser

In this paper,we investigate laser cleaning using a flattened top laser to remove paint coating from a metal substrate.Under the irradiation of a flattened top laser,the coating paint of the metal substrate can be removed efficiently by laser induced ablation,stress,and displacement force.The temperature distribution,stress,and displacement are calculated in the coating layer and substrate using finite element analysis.The effects of a Gaussian laser and a flattened top laser and the results of different diameters of laser spot are compared.The investigation shows that the flattened top laser can reduce the substrate damage and enhance the cleaning efficiency.This method meets the need of large area industrial cleaning applications by optimizing the flattened top laser parameters.     

苯丙烯类葡萄糖氧苷的合成及其抗缺氧活性

以取代苯甲醛(1a~1t)为原料,通过Knoevenagel缩合、酯化和LiAlH₄还原等反应制得苯丙烯醇衍生物(3a~3t);以取代肉桂醛(1u~1x)为原料,经NaBH₄还原制得苯丙烯醇衍生物(3u~3x); 3a~3x与全乙酰化溴代葡萄糖经Koenigs-Knorr偶联反应及MeONa/MeOH体系脱除乙酰保护基反应,合成了24个苯丙烯类葡萄糖氧苷(5a~5x),其中5c,5f ~ 5x为新化合物,其结构经¹H NMR和ESI-MS表征。采用MTT法测定了5对缺氧损伤的内皮细胞(EA.hy926)的抗缺氧活性。实验结果表明： 5b, 5e, 5g, 5p, 5q, 5s, 5t和5y对EA.hy926的抗缺氧活性均高于经景天苷。     

A New 3-D Gd(III) Coordination Polymer Constructed with Mixed Aromatic Acid: Synthesis,Structural Characterization and Magnetic Characterization

Abstract  

Using pyridine-2,5-dicarboxylic acid (2,5-pdcH₂) and Gd₂O₃, a new three-dimensional (3D) polymeric complex, [Gd(2,5-pdc)(nic)·H₂O] _n (1) was synthesized under hydrothermal conditions, in which nic (nicotinate; also named as pyridine-2-carboxylic acid) might have been formed from the 2,5-pdc ligands through the C–C bond cleavage and release of CO₂ molecules. The complex crystallizes in monoclinic system, space group P2₁/c with unit cell parameters a = 9.221(9) Å, b = 14.179(14) Å, c = 10.516(10) Å, β = 95.658(14)°, V = 1,368(2) Å³ and Z = 2. 2,5-pdc ligands bridge gadolinium centers to form the three-dimensional framework featuring hexagonal channels along the axis a which are occupied by bridging nic anions and mono-coordinated water molecules. Magnetic properties have been investigated in the range of 2–300 K reveal that t there is very weak antiferromagnetic exchange between the Gd(III) ions (J = −0.017 cm⁻¹).     

Analysis of transition between chaos and hyper-chaos of an improved hyper-chaotic system

An improved hyper-chaotic system based on the hyper-chaos generated from Chen's system is presented, and some basic dynamical properties of the system are investigated by means of Lyapunov exponent spectrum, bifurcation diagrams and characteristic equation roots. Simulations show that the new improved system evolves into hyper-chaotic, chaotic, various quasi-periodic or periodic orbits when one parameter of the system is fixed to be a certain value while the other one is variable. Some computer simulations and bifurcation analyses are given to testify the findings.     

Studies on the Bicyclolphosphite of Saccharides

Bicyclophosphitication of saccharide was used for synthesis of optically active organic phosphor compounds widely. The sugars contained phosphite ring are the inductor in stereochemistry. The nucleophilic subsitution on tetrahedron-phosphor atom is provided with specific stereo-direction. These compounds, with highly stereoselectivity, and can be used as the highly selectivity reagent for organic reactions.     

燕山海泡石的研究及其在C1化学中的应用(英文)

采用化学分析、ＸＲＤ、ＦＴＩＲ、ＤＴＡ、ＴＧＡ、ＳＥＭ、ＴＥＭ以及ＢＥＴ吸附等方法对燕山海泡石的物理化学性能进行了表征。选择了四个反应体系表征海泡石载体催化剂的催化性能,即二氧化碳加氢甲烷化、二氧化碳加氢合成低碳烯烃、甲烷化法挣化合成氨原料气和选择氧化反应。结果表明,海泡石载体催化剂的催化活性优于以氧化铝和二氧化硅为载体的传统催化剂的催化活性。