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Three MnO2 samples with different well-defined morphologies including nanoplates, nanorods and corallines are prepared through a simple chemical precipitation method and used as the promoter/support for Pt electrocatalysts (denoted as Pt/MnO2 P, Pt/MnO2-R and Pt/MnO2 C, respectively). The morphology effects of MnO2 to the catalytic properties of Pt for methanol oxidation reaction (MOR) are intensively investigated. Results show that the catalytic properties of Pt are strongly dependent on the morphology of the promoter. Pt/MnO2-R with MnO2 nanorods as the promoter shows the highest catalytic properties among the MnO2-promoted catalysts. The mass-specific activity and intrinsic activity of Pt in Pt/MnO2-R catalyst is 0.51 A mg−1Pt and 11.54 A m−2Pt, which is ca. 1.89 and 2.18 times that of commercial Pt/C catalysts (0.27 A mg−1Pt and 5.29 A m−2Pt), respectively. Change in the electronic structure of Pt is responsible for the enhancement in the catalytic properties of Pt/MnO2-R.

The promoting effect of metal oxides to Pt catalysts toward methanol oxidation reaction (MOR) has attracted widespread attention in recent years. In this communication, we report the promoting effect of MoO3 to Pt catalyst by rationally designing and tuning the nanostructure of the catalysts. MoO3 nanorods are firstly synthesized through hydrothermal method and used as the substrate for the deposition of polyaniline (PANI) layer. The PANI-MoO3 composite nanostructures are then used as the support for Pt catalyst. Depending on the preparation method of Pt nanoparticles, the nanostructure can be PANI nanotube supported Pt (Pt/PANI) through etching MoO3 nanorods with NaBH4 and PANI-MoO3 composite nanorods supported Pt (Pt/PANI-MoO3). The catalytic properties of the two catalysts toward MOR are investigated. Results show that the current of methanol oxidation on Pt/PANI-MoO3 catalyst is comparable to that on Pt/PANI, while the peak potential of MOR on the former is lowered by 180 mV as compared with the latter, suggesting a much higher catalytic activity of Pt/PANI-MoO3. The presence of MoO3 may be responsible for the improvement of the catalytic properties through the co-synergistic effects of PANI and MoO3.

Asthma is a chronic inflammatory, heterogeneous airway disease affecting millions of people around the world. Curcumin has been found to have anti-inflammatory and antifibrosis effects. Researchers reported that curcumin regulated Wnt/β-catenin signaling in lots of cells. However, whether curcumin regulates the levels of Wnt/β-Catenin signaling in lung tissues and DCs (dendritic cells) remains unclear. In this study, we assessed the effects of curcumin on DCs and asthma.C57BL/6 mice immunized with OVA (ovalbumin) were challenged thrice with an aerosol of OVA every second day for 8 days. Dexamethasone or curcumin was administered intraperitoneally to OVA-immunized C57BL/6 mice on day 24 once a day for 9 days. Mice were analyzed for effects of curcumin on asthma, inflammatory cell infiltration and cytokine levels in lung tissue. DCs were isolated from mouse bone morrow. The surface markers CD40, CD86 and CD11c of DCs was detected by FACS (fluorescence activated cell sorting) and the function of DCs was detected by mixed lymphocyte reaction. The expression of GSK-3β and β-catenin was detected by Western Blot.Results showed that OVA increased the number of inflammatory factors in BALF (bronchoalveolar lavage fluid), elevated lung inflammation scores in mice. Curcumin dose-dependently reversed the alterations induced by OVA in the asthmatic mice. Curcumin activated Wnt/β-catenin signaling pathway in DCs and asthmatic mouse lungs.Curcumin could influence the morphology and function of DCs, ease asthma symptom and inflammatory reaction through the activation of Wnt/β-catenin signaling. These results provide new evidence new evidence for application of curcumin on asthma.