An Empiric Linear Formula between the Internal Tetrahedron Symmetric Stretch Frequency and the Al Content in the Framework of KL Molecular Sieves

Since 1960's zeolite molecular sieves materials have been widely used in catalysis, adsorption, separation, host-guest chemistry and supramolecular science. During the research and application, the framework compositions of zeolite molecular sieves materials usually have to be determined, especially when the framework compositions are modified. Based on X-ray diffraction (XRD) peak positions and infrared (IR) spectroscopy frequencies, some empiric linear relationships have been reported t…     

A Strain Sensor Based on OTDR for Gas Trunk Pipelines

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｔｈｅｌａｎｄｓｕｂｓｉｄｅｎｃｅｅｆｆｅｃｔｏｎｕｎｄｅｒｇｒｏｕｎｄｐｉｐｅｌｉｎｅｉｓｓｅｖｅｒｅ ,ｂｅｃａｕｓｅｔｈｅｓｅｐｉｐｅｌｉｎｅｓａｒｅｕｓｕａｌｌｙｂｕｒｉｅｄｂｅｌｏｗｇｒｏｕｎｄａｂｏｕｔ1 .5ｍ .Ｆｏｒｅｘａｍｐｌｅ,ｔｈｅａｖｅｒａｇｅｈｅｉｇｈｔｏｆｌａｎｄｓｕｂｓｉｄｅｎｃｅｉｓ 50～ 1 0 0ｍｍｉｎＸｉｑｉｎＤｉｓｔｒｉｃｔ,ａｎａｃｔｉｖｅｓｕｂｓｉｄｉｎｇｒｅｇｉｏｎｉｎＴｉａｎｊｉｎ .Ｔｈｅａｃｃｕｍｕｌａｔｅｄｓｕｂｓｉｄｅｎｃｅ…     

A New Taraxastane-type Triterpenoid from Potentilla multicaulis

The genus Potentilla (Rosaceae) consists of about 200 species distributed in many countries, among them about 90 species grow in China1. Some species of Potentilla plants have long been used as traditional Chinese medicinal herbs for anti-rheumatism, deto…     

Monodentate phosphorus-coordinated palladium(Ⅱ)complexes as new catalyst for Mizoroki-Heck reaction of aryl halides with electron-deficient olefins

Four novel monodentate phosphorus-coordinated palladium(Ⅱ) complexes derived from 3,5-disubstituted-1H-1,2,4-diazaphospholes were developed as efficient catalyst for Mizoroki-Heck reactions of aryl halides with electron-deficient olefins. The role of these monophosphine ligands in catalysis was illustrated by control experiments using Pd salt and ligands as combined catalyst.     

Synthetic [FeFe]-H2ase models bearing phosphino thioether chelating ligands

Through the oxidation-reduction combination procedure, the neutral tri-substituted {2Fe3S} complex 2 was synthesized by replacing the CO ligand in 1 with phosphine. This substitution leads to the Fe-Fe bonds in 1 and 2 with large Lewis basicity difference, i.e. △pK_a^MeCN~10.     

Synthesis of a reduction-sensitive Bletilla striata polysaccharide amphiphilic copolymer

A reduction-sensitive stearic acid modified-Bletilla striata polysaccharide amphiphilic copolymer is synthesized. The copolymer enabled to spontaneously form micelles which display faster docetaxel release rates under reduction condition and enhanced anticancer activity in vitro after incorporating docetaxel into micelles.     

Screening the anti-gout traditional herbs from TCM using an in vitro method

The aim of this work was to evaluate the ability of 33 herbal extracts in inhibiting the acute inflammation and xanthine oxidase(XOD) activity.The anti-inflammation effects of the herbal extracts were detected by an in vitro cell model,which was established by stimulating human umbilical vein endothelial cells(HUVEC) using sodium urate(MSU).In this model,the intercellular adhesion molecule-1(ICAM-1) and interleukin-1 beta(IL-1β) were expressed,and the anti-inflammation effects of herbal extracts were evaluated by detecting the content changes of ICAM-1 and IL-1β in cell lysates and cell culture supernates using an enzyme-linked immunosorbent assay(ELISA).Moreover,an ultrahigh performance liquid chromatography and tandem mass spectrometry(UPLC-MS/MS) method was used for the detection of XOD activity and the screening of XOD inhibitors in this research.The amount of uric acid from each analyte was directly detected using the multiple reaction monitoring mode and the uric acid level could be reduced via the addition of an inhibitor.Results indicated that Salviae Miltiorrhizae Radix et Rhizome,Rhei Radix et Rhizoma,Polygoni Cuspidati Rhizoma et Radix,Selaginellae Herba,Paeoniae Radix Rubra,especially Ginkgo Folium seemed to be more effective in anti-inflammation and inhibiting XOD activity.The anti-inflammation and enzyme inhibitory activities of the herbal extracts may be correlated with their bioactive components.And the differences between the herbal extracts were correlated with the amount of flavonoid and anthraquinone components.In our study,we have investigated the potential anti-inflammation bioactivity of 33 herbal extracts in vitro,which could provide a reference for further in vivo research in the prevention and treatment of gout.     

Vanadium-based cathodes for aqueous zinc ion batteries: Structure,mechanism and prospects

As an emerging energy storage device with high-safety aqueous electrolytes, low-cost, environmental benignity and large-reserves, the rechargeable aqueous zinc-ion batteries(AZIBs) have attracted more and more attention. Vanadium-based compounds are also supposed as the potential candidate cathode materials for AZIBs due to their wide variety of phases, variable crystal structures and high theoretical capacity. In this review, the recent progress in the development of vanadium-based materials wa...     

Structural determination of flavonoids from Sophora flavescens

Eight flavonoids were isolated from Sophora flavescens. Among them, three prenylflavanones: (2S)-6[2(3-hydroxyisopropyl)-5-methyl-4-hexenyl]-5-methoxy-7,2', 4'-trihydroxyflavanone (1), (2S)-5, 4'-dimethoxy-8-lavandulyl-7, 2'-dihydroxy flavanone (2) and (2S)-8-(5-hydroxy-2-isopropenyl-5-methylhexyl)-7-methoxy-5,2', 4'-trihydroxyflavanone (3) are new compounds. Their chemical structures were determined by spectral methods including 2D NMR.     

An enantioselective biginelli reaction catalyzed by a simple chiral secondary amine and achiral brønsted acid by a dual-activation route

An enantioselective Biginelli reaction that proceeds by a dual‐activation route has been developed by using a combined catalyst of a readily available trans‐4‐hydroxyproline‐derived secondary amine and a Brønsted acid. Aromatic, heteroaromatic, and fused‐ring aldehydes were found to be suitable substrates for this multicomponent reaction. The corresponding dihydropyrimidines were obtained in moderate‐to‐good yields with up to 98 % ee under mild conditions. Based on the experimental results and the observed absolute configurations of the products, a plausible transition state has been proposed to explain the origin of the activation and the asymmetric induction.