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This study reports on the thiourea dioxide catalyzed transfer hydrogenation of diverse C=N–containing heterocyclic compounds with Hantzsch ester as the hydrogen source. With this cost effective and readily available catalyst, a wide range of 2-substituted quinolines, 3-substituted-2H-1,4-benzoxazines and 3-substituted-2H-1,4-benzothiazines were efficiently reduced to the corresponding tetrahydroquinolines, dihydro-2H-benzoxazines and dihydro-2H-benzothiazines under mild conditions. This study reports on the first thiourea dioxide catalyzed transfer hydrogenation of 2-substituted quinolines, 3-substituted-2H-1,4-benzoxazines and 3-substituted-2H-1,4-benzothiazines with Hantzsch 1,4-dihydropyridine as the hydrogen source.

A simple and readily available cyclopentadiene-based Bronsted acid was employed to catalyze the transfer hydrogenation of 2-substituted quinolines using Hantzsch ester as the hydrogen source. This conceptually new designed organocatalyst demonstrates remarkably high efficiency for this transformation and a variety of substituted 1,2,3,4-tetrahydroquinoline derivatives were afforded in excellent yields under mild reaction conditions.

The microstructures and properties of ultrasonic and conventional cast 7050 aluminum alloys have been studied. Compared with the conventional cast alloy, the ultrasonic cast ingot (UI) is characterized with a finer microstructure than that in the conventional cast ingot (CI). For the hot-rolled plates, the UI alloy can be aged faster and aging-strengthened easier than the CI alloy. When aged at 120 °C, the UI alloy reaches its peak strength after 8 h, with tensile strength of 602 MPa, yield strength of 547 MPa and elongation of 12.7%, respectively, whereas the CI alloy plate is with its tensile strength, yield strength and elongation of 536 MPa, 462 MPa and 15.0%, respectively, after peak aged for 12 h.

This study reports on the first transfer hydrogenation of 2-substituted quinolines promoted by a thiourea catalyst with Hantzsch ester as the hydrogen source. A wide range of quinoline derivatives, including 2-alkylquinolines and 2-arylquinolines, were efficiently reduced to give 1,2,3,4-tetrahydroquinolines with good to excellent yields. The operational simplicities and conveniences of this reaction pathway render this protocol considerably promising in the preparation of biologically active tetrahydroquinoline derivatives.

Objectives The present study aimed to investigate whether salidroside can induce differentiation of rat mesenchymal stem cells (rMSCs) towards hepatocytes in vitro and the mechanism of hepatic differentiation of rMSCs. Methods rMSCs were subject to hepatic differentiation. One, two and three weeks later, the expression of alpha fetoprotein (AFP) and albumin (ALB), cytochrome P450 (CYP450)-dependent activity and inducibility, cellular uptake of low density lipoprotein (LDL) and urea synthesis were assessed and the hepatic differentiation of rMSCs was evaluated. In order to unravel the mechanism of hepatic differentiation of rMSCs in vitro, inhibitors of extracellular regulated kinase1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3K) and p38 were applied. When the process of hepatic differentiation was completed, special proteins of hepatic differentiation were detected and blocking of inhibitors was evaluated. Key findings Salidroside significantly induce differentiation of rMSCs towards hepatocytes. Differentiated rMSCs have typical functional hepatic characteristics. The results also showed that the ERK1/2 and PI3K signalling pathways play important roles in the regulatory effects of salidroside on hepatic differentiation of rMSCs and are involved in cell fate determinations, while the p38 signalling pathway does not. Conclusions Salidroside can induce differentiation of rMSCs towards hepatocytes in vivo, and the ERK1/2 or PI3K signalling pathway underlie the process of hepatic differentiation.

Allium chinense, a traditional herbal medicine, has been used for the treatment of cardiovascular diseases for hundreds of years. In this study, A. chinense steroids (ACSs) including three steroidal glycosides and their parent aglycones were isolated from the bulbs of A. chinense. For the first time, their cardioprotective effects were evaluated in cultured rat cardiac H9C2 cells by pretreatment with ACSs for 24 h before exposure to 0.2 mm H2O2. The results showed the cell viability decreased markedly when H9C2 cells were incubated with 0.2 mm H2O2 alone for 2 h, while the cell lipid peroxidation (estimated by the excessive production of nitric oxide and malondialdehyde) and intracellular free calcium concentration ([Ca2+]i) increased significantly. The addition of 20 μm (below the toxic concentration) of ACSs notably attenuated the cellular injury induced by H2O2. The effects of ACSs in our experiments were similar to those of nimodipine, a clinically applied calcium channel blocker. Preliminary analysis of the structure–activity relationship indicated that ACSs with a spirostane-type skeleton exhibited stronger protection than that with a furostane-type skeleton, and glycosylation of the steroids could substantially lower the protective activities. The above results suggested the protective effects of steroids originated from A. chinense on the oxidative injury of H9C2 cells and ACSs may have potential for preventing cardiac injuries induced by oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.

A new family of organometallic/inorganic nanohybrid Langmuir–Blodgett (LB) films consisting of rigid-rod organomercury acetylide complex (OMA) as the π-conjugated organometallic composite and heteropolyacid salts MPA (MPA = K3PMo12O40, K5BW12O40, Na5IMo6O62) of the Keggin and Anderson structures as the inorganic composite, were prepared and characterized by π−A isotherms, UV−Vis absorption spectra, fluorescence spectra, scanning tunneling microscopy, atomic force microscopy imaging and low-angle X-ray diffraction. Our experimental results indicate that steady Langmuir and LB films are formed in pure water and heteropolyacid salt subphases. Luminescence spectra of hybrid LB films show that MPA can quench the emission of OMA to some extent. These alkynylmercury(II) based LB films display interesting electrical conductivity behavior. They all show decent electrical conductivity, and the tunneling current amounts to ±100 nA when the voltage is set at ±3 ∼ ±5 V.

A new family of organometallic/inorganic composite Langmuir-Blodgett (LB) films consisting of rigid-rod polyplatinayne polymer ((Pt-T(OMe-Fl)T)? or (Pt-T(F-Fl)T)?, where the triplet bonds are abbreviated by T, and fluorene ring by Fl) as the p-conjugated organometallic molecule, polyoxometalate (POM, POM ¼ K3PMo12O40 ,H 3PW12O40 ,o r H 6P2W18O62) of the Keggin and Dawson structures as the inorganic component, and dimethyldioctadecylammonium bromide (DODA) or a mixture of octadecanoic acid (OA) and docosanoic acid (DA) as the auxiliary film- forming agent were prepared and characterized by p-A isotherms, UV-Vis absorption spectra, photoluminescence spectra, atomic force microscopy imaging, scanning tun- neling microscopy, and low-angle X-ray diffraction. Our experimental results indicate that steady, even, and ordered Langmuir and LB films are formed in pure water and polyoxometalate subphases. It was shown that the POM molecules are probably em- bedded inside the polyplatinayne molecules in the LB film structure and they can quench the luminescence of the Pt polyyne. These Pt-polyyne based LB films display interesting electric conductivity behavior. (Pt-T(OMe-Fl)T)?/DODA/HPW12 monolayer film shows a good electrical conductivity, and the tunneling current amounts to 6100 nA when the voltage is set at 6 8V.V C 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3193-3206, 2008

A new polarization-independent dual-wavelength fibre laser by fabricating a uniform FBG and a chirped FBG in a polarization-maintaining erbium-doped fibre (PM-EDF) is proposed and demonstrated. The wavelength spacing is 0.18nm and the optical signal-to-noise ratio is greater than 50dB with pump power of 246mW. Chirped FBG is used to make the reflectivity wavelengths of two PM-FBGs match easier. Since both EDF and FBGs are polarization-maintaining without splices and the two wavelengths are polarization-independent, the maximum amplitude variation and wavelength shifts for both lasing wavelength with 3-min intervals over a period of six hours are less than 0.2 dB and 0.005 nm, respectively, which shows stable dual-wavelength output.

A new family of organometallic/inorganic hybrid Langmuir-Blodgett (LB) films, consisting of organometallic mercury acetylide (OMA) as the π-conjugated organometallic molecule and polyoxometallate (POM, POM = K5BW12O40 or Na5IMo6O24) of the Keggin and Anderson structures as the inorganic composite and docosanoic acid (DA) as the auxiliary film-forming agent, were prepared and well characterized by π–A isotherms, UV-vis absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunnelling microscopy, and low-angle X-ray diffraction. Our experimental results indicate that stable and well defined monolayer Langmuir and LB films are formed in pure water and POM subphases. There is a quenching effect in the luminescence intensity of the mercury complex when it is made into the LB films due to the enhanced aggregation phenomenon. These alkynylmercury(ii) based LB films exhibit interesting electrical conductivity behaviour, dependent of the characteristics of the POM used. They all reveal decent electrical conductivity, and the tunnelling current can reach ±100 nA when the voltage is set at –5 to +5 V.

The characteristics of co-doping Al3+ in ytterbium-doped silica-based fiber used for high-power cladding pumped laser were analyzed based on experimental analysis. The results show that the optimum mole percent of Al3+ to Yb3+ is 9—11 for high concentration of ytterbium-doped silica-based fiber at which low concentration quenching probability, high absorption coefficient and proper numerical aperture can be obtained. Meanwhile, ytterbium-doped silica-based fiber preforms were fabricated by MCVD and special solution doping technique. By soot layer temperature experiment and test of the related parameters of the drawn fiber, the results show that the optimum temperature for making soot layer can be accurately controlled and the absorption coefficient at 976 nm was as high as 620 dB/m with good repeatability. This conclusion makes a useful reference for fabrication of ytterbium-doped Al3+ co-doped fiber.