Interaction of Chelerythrine Choloride in Acid Buffer with Calf-thymus DNA

Several benzo[c]phenanthridine alkaloids (BPA) were found in plants of Caprifoliaceae, Fumariaceae, Meliaceae, Papaveraceae, and Ruracea families1. BPA represent a group of natural products, exhibiting multiple pharmacological properties and biological ac…     

Synthesis and Characterization of Amphiphilic Block Copolymer Containing PVP and Poly(5-benzyloxytrimethylene carbonate)

Amphiphilic block copolymers have attracted great interest recently, especially for thebiomedical uses1, . The hydrophilic blocks improve the biocompatibility of copolymer, 2while the hydrophobic blocks enhance the mechanics of the material and providever…     

一个截断误差诱导下的随机数字振荡系统

计算机截断误差通常被认为会导致混沌系统退化.根据这种认识，提供了一个完全由计算机截断误差诱导的简单系统走向复杂化或混沌的反例.该系统定义为椭圆反射腔映射系统的过焦系统，理论解为一个极限序列，对应计算机解则是一个随机数字振荡系统.分析表明，计算机解是在截断误差诱导下由理论解变异而来的.理论解中系统存在“回转机制”，截断误差诱导系统在非双曲性不动点局域产生“逃逸机制”，从而发现一种阵发混沌的新机制. 关键词： 截断误差 切延迟椭圆反射腔映射系统 随机振荡 阵发混沌     

Rheological and DSC Studies on the Interaction between κ-Carrageenan and Cellulose Nanocrystals (CNC)

The κ-carrageenan comes from a family of linear water-soluble polysaccharides extracted from different species of marine red algae with a primary structure of an alternating disaccharide with repeating unit of 3-linked β-D-galactose 4-sulfate and 4-link…     

Peduncin, A New Indole Alkaloid from Pueraria peduncualris

Pueraria peduncularis (Grah. ex Benth.) Benth. is a plant of Leguminosae which grows in the southwest of China. Different from other plants of Pueraria, it could not be used as a medicine due to its toxicity1. In order to use the Pueraria plants safer, we studied the constituents of P. peduncularis. Previous phytochemical studies of an n-BuOH extract afforded three triterpenoid saponins2-3. The continuing investigation on CHCl3 extract led to the isolation of a new indole alkaloid. …     

Novel Stereoselective Synthesis of 1,3-Dienyl Tellurides by Palladium Catalyzed Cross-coupling Reaction of (E)-β-Bromovinyl Tellurides

Conjugated dienes are valuable intermediates in organic chemistry. Many biologically active compounds occurring in nature possess the structural skeleton of conjugated dienes such as chillea amide1 and pelltoine2. Besides, the synthesis of conjugated dienes for use in the Diels-Alder reaction is still an important challenge in organic synthesis. One particularly attractive approach has been the incorporation of heteroatom substituents that can activate the diene3.Recently, we found that β-br…     

Spectroscopic Study of the Interaction of Bu_2SnCl_2 with EHPG

A number of Sn (Ⅳ)complexes have been synthesized since 1980 and tested its anticancer activity1. The simplest complex Bu2SnCl2 has activity to P388 tumor cells. Several metal complexes such as Ru-ind (trans-indazolium (bisindazole) tetrachloro- ruthenate (Ⅲ)) had used transferrin as a drug delivery system, the complexes still exhibit high antitumor activity and lower toxicity2. We use EHPG as a model ligand3 to study the interaction between Bu2SnCl2 and EHPG. EHPGAt first, we stud…     

Resveratrol Tetramers from the Roots of Ampelopsis sinica

Various biological activities of stilbenoids have been described, such as antifungal and antibacterial activities1, antihepatotoxic activity2-4, anti-HIV activity5. Stilbenoids mainly existed in Vitaceae, Diperocarpaceae, Gnetaceae, Cyperaceae, Leguminase1. Many oligostilbenes have been isolated from Vitaceaeous plants. But, there was no report on the stilbenoids in Ampelopsis sinica (Miq.) W. T. Wang which was traditionari- ly used to treat arthritis6. In our study on the constituen…     

Cross-linking Copolymerization of Acrylic Acid and Multi-armed Cross-linkers

Polymer gels are of considerable interests in material science1-3. Many theoretical and experimental studies have been made on the cross-linking copolymerization4-6 of these systems. Recently, in situ interferometry is applied in studying this process7-9. As shown in Figure 1, the common two-armed cross-linkers will lead to defects in the network, while multi-armed cross-linkers will enhance the integrity of the network. This paper studies the cross-linkers influence on cross-linking and t…     

SYNTHESIS OF A SERIES OF NOVEL ORGANIC COMPOUNDS WITH TWO-PHOTON ABSORPTION AND TWO-PHOTON PUMPED LASING

Two-photon absorption (TPA) occurs through the simultaneous absorption of two photons via virtual states in a medium. Materials with large TPA cross section are gaining increasing attention recently due to their potential applications in optical data storage, two-photon up-converted lasing, two-photon-laser scanning fluorescence microscopy, optical power limiting and photodynamic therapy1-3. Numerous organic compounds have been investigated both experimentally and theoretically in order to u…