Superconductivity of MI(MII0.5, Si0.5)2 (MI=Sr and Ba, MII=Al and Ga), ternary silicides with the AlB2-type structure

Ternary silicides MI(MII0.5, Si0.5)2 (MI=Sr and Ba, MII=Al and Ga) were prepared by Ar arc melting. Powder X-ray diffraction indicates that they have the AlB2-type structure, in which Si and MII atoms are arranged in honeycomb layers and MI atoms are intercalated between them. Electrical resistivity and dc magnetization measurements revealed that Sr(Al0.5, Si0.5)2 is superconductive, with a critical temperature for superconductivity (TC) of 4.2 K, while Ba(Al0.5, Si0.5)2 is not at temperatures ranging above 2.0 K. Sr(Ga0.5, Si0.5)2 and Ba(Ga0.5, Si0.5)2 are also superconductors, with TCs of 5.1 and 3.3 K, respectively.Comment: 5 pages, 3 tables, 4 figure

Brain-specific gene expression by immortalized microglial cell-mediated gene transfer in the mammalian brain

AbstractThe intra-arterial injection of immortalized microglia transfected with the lacZ gene, resulted in the expression of β-galactosidase in the rat brain at 48 h and the activity of β-galactosidase was detected for up to 3 weeks post-injection. More than 30-fold higher activity of β-galactosidase was detected in the brain than in the liver, lung or spleen at 48 h post-injection. This method allows us to easily deliver the gene of interest to the brain without influencing other organs. Our brain-targeting gene delivery system can facilitate gene therapy of several brain disorders, including brain tumor, metabolic disorders, and degenerative disorders, as well as investigation into the roles of particular genes in brain function and development