RESUMO
The effects of pressure on the superconducting properties of a Bi-based layered superconductor La2O2Bi3Ag0.6Sn0.4S6, which possesses a four-layer-type conducting layer, have been studied through the electrical resistance and magnetic susceptibility measurements. The crystal structure under pressure was examined using synchrotron x-ray diffraction at SPring-8. In the low-pressure regime, bulk superconductivity with a transition temperatureTcof â¼4.5 K was induced by pressure, which was achieved by in-plane chemical pressure effect owing to the compression of the tetragonal structure. In the high-pressure regime above 6.4 GPa, a structural symmetry lowering was observed, and superconducting transitions with aTcâ¼ 8 K were observed. Our results suggest the possible commonality on the factor essential forTcin Bi-based superconductors with two-layer-type and four-layer-type conducting layers.
RESUMO
The black-bellied hornet Vespa basalis is responsible for the large quantity of accidents and severe wasp envenomation in China. This study aims to identify the rat pain responses induced by experimental V. basalis sting and related-components in the venom. It was observed that unilateral intraplantar injection of crude V. basalis venom could induce several kinds of pain related behaviors in a dose-dependent manner including spontaneous pain, unilateral thermal and unilateral mechanical hypersensitivity at different time courses. Fourteen main fractions were separated from the crude venom of V. basalis using high performance liquid chromatography, among them, five components (1, 3, 4, 9 and 12) could absolutely mimic the crude venom-induced pain behaviors. According to the molecular mass and N-terminal sequence, the component 3 and 4 were identified as Mastoparan B and HP-1 respectively, the component 9 was speculated as a novel variant of HP-1/2. In addition, the other two sub-components (1-1 and 1-2) purified from component 1 cannot be determined. The results offered the key information about six active polypeptides from V. basalis contributing to pain responses, which might provide a basis for exploring mechanisms of wasp sting injury.
