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…     

Lipase-catalyzed hydrolysis of methyl-3-phenylglycidate

Large amount of facts indicated that enantiomers were different from each other in biological activity, physiological activity and toxicity in clinical applications1. It resulted in the increase of interest on preparation of chiral drugs. Optical active 3-phenylglycidic ester, especially (2R,3S)-methyl 3-phenylglycidate is an important starting material for production of many chiral drugs, such as taxol, (2R,3S)-diltiazem etc2,3.For the above purpose, a series of lipases were screened. Final…     

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…     

A New Benzosesquiterpenoid Dimer from Polyalthia cheliensis Hu

The genus plants Polyalthia, being rich in bioactive diterpenoids and alkaloids1,2, have been attracting much attention. Polyalthia cheliensis Hu is a bush mainly distributed in Xishuangbanna, Yunnan Province of China. The previous researches1 reported the isolations of four clerodane diterpenes from the stem bark of this plants. Recent phytochemical work on its dried leaves results in the elucidations of a new benzosesquiterpenoid dimer, 3((, 3(((-bispolycerasoidol (1) and its monomer, a kn…     

NO Decomposition on Rh Supported CNTs

It is well known that NO is one of the most predominant pollutants. It is the main source of acid rain and has strong carcinogenicity. Therefore, removal of NO is one of the key environmental subjects in the world nowadays. With the discovery of carbon nanotubes and their large-scale synthesis1-2, attention is now being focused on their potential application in various fields of materials research. In the field of heterogeneous catalysis, numerous carbon materials have been used to disperse …     

Design and Synthesis of Lipids Bearing Nucleosides as Gene Vectors

Delivery of exogenous DNA into cells of various origins plays an important role not only in basic research, but also in clinical application in gene therapy. Great efforts have been made towards the development of viral and nonviral vectors for these purposes1~6. However, at the present stage, none of the vectors can claim to be the panacea. Although most viral vectors can transfer gene efficiently and some of them can be used for gene transfer into tissue cells in vivo, they suffer from immu…     

Formation of Benzyl Oxazole, A Competitive Path with the Classical Bishler-Napieralski Reaction

1,2,3,4-tetrahydroisoquinoline-3-carboxylic acids (TIC) are of considerable interest due to their biological activity and as an important structural element in several important alkaloids and other medically useful products1. Moreover, TIC is a phenylalanine analogue in which the dihedral angle is limited to a very small range because of its bicyclic nature2. In connection with the design of topographically constrained peptides, TIC has been utilized in several instance as a replacement o…     

Hydrothermal Synthesis and Structure of[{Mo_8V_4O_(36)(VO_4)(VO)_2}n]~(7n-)Bi-capped α-Keggin Fragments Linked to a Chain

The title compound, (H2en)3H3O{Mo8V4O36(VO4) (VO)2} ?4H2O, was hydrothermally synthesized and structurally characterized by means of IR, ESR spectrum and single crystal X-ray diffraction. It crystallized in a monoclinic system with space group P21/c, a=1. 980 4(4) nm, 6=2. 063 4(4) nm, c=l. 192 0(2) nm, =94. 76(3)?and deep black colour. The compound contains V-centered bi-capped a-Keggin fragments {Mo8V7O42} that are linked together by edge-shared units V O5 via V桹梀 bonds, forming a chain.     

On Vector Helmholtz Equation with a Coupling Boundary Condition

The Helmholtz equation is sometimes supplemented by conditions that include the specification of the boundary value of the divergence of the unknown.In this paper, we study the vector Helmholtz problem in domains of both C~(1,1)and Lipschitz.We es- tablish a rigorous variational analysis such as equivalence,existence and uniqueness. And we propose finite element approximations based on the uncoupled solutions.Fi- nally we present a convergence analysis and error estimates.     

A New Diterpene Glycoside from Isodon forrestii

The genus Isodon has been shown to be a rich source of diterpenes, especially the highly oxidized ent-kaurene diterpenoids with various biological activities1-3. The chemical constituents of Isodon forrestii was reported by Yun Long Xu et al.4. We have investigated the titled plant collected in another place, from the 70% acetone extract of the aerial parts of I. forrestii, seven compounds including a new diterpene glycoside 1 were isolated by a combination of silica gel, preparative TLC an…