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High-quality ZnO films have been grown on Zn-polar ZnO substrates by plasma-assisted molecular beam epitaxy. With increasing O/Zn ratio from the stoichiometric to the O-rich flux condition, the growth mode and the surface morphology changed from three-dimensional growth with a rough surface to two-dimensional growth with a smooth surface. The minimum linewidth from the (10 1 10) !-rocking curve was 100 arcsec, and the n ¼ 2 state of A-exciton was clearly observed in the photoluminescence at 4.2 K. Due to the reduction in the edge-type threading dislocation density, the residual carrier concentration in these homoepitaxial ZnO films was as low as 2:2 Â 10 16 cm À3 , which is one order of magnitude lower than that previously reported for heteroepitaxial ZnO films.

Nanoantenna-like properties of sea-urchin shaped ZnO as a nanolight filter Appl. Phys. Lett. 101, 133101 (2012) Leaky mode analysis of luminescent thin films: The case of ZnO on sapphire J. Appl. Phys. 112, 063112 (2012) ZnO/ZnSxSe1−x core/shell nanowire arrays as photoelectrodes with efficient visible light absorption Appl. Phys. Lett. 101, 073105 (2012) Study of the photoluminescence emission line at 3.33eV in ZnO films

Polarity-controlled ZnO films with an MgO buffer layer were grown on c-plane sapphire by plasma-assisted molecular-beam epitaxy. Convergent beam electron diffraction results showed that Zn-polarity (+c) growth occurred when the MgO layer was thicker than 3 nm, whereas O-polarity (−c) growth occurred when the layer was less than 2 nm. Reflection high-energy electron diffraction results revealed that MgO growth was Stranski–Krastanov mode, and that the growth mode transition from two- to three-dimensional occurred when the layer was thicker than 1 nm. In conclusion, polarity conversion apparently occurs due to the different atomic structure between the wetting layer and islands of MgO.

Annexin (AX) constitutes a new family of Ca2+-dependent membrane-binding proteins; 13 of them have been described. Among these, annexin-1 (AX-I) has displayed many biological functions in vitro. Its actual role in vivo, however, remains unknown. We already reported that AX-I was expressed in proliferating (regenerating) hepatocytes at both protein and messenger RNA (mRNA) levels. The role of AX-I in human hepatocellular carcinoma (HCC) remains obscure. In this study, the amounts of AX-I at protein and mRNA levels, as well as its localization, have been determined in the normal human liver, chronic hepatitis liver, and nontumorous and tumorous portions of HCC. AX-I was rarely found in normal and chronic liver tissues, whereas it is overexpressed at both the transcriptional and translational levels in tumorous and nontumorous regions of HCC. In addition, more AX-I was expressed in the tumorous portion than the nontumorous portion of HCC. AX-I was present in the hepatocytes and HCC cells, localized mainly in the cytoplasm. AX-I was expressed in poorly differentiated cancer cells. Furthermore, AX-I was tyrosine-phosphorylated in HCC. We also found that some of the AX-I- positive hepatocytes in the nontumorous tissues were derived from a particular subset of parenchymal cells (stem or oval cells). These results indicate that AX-I plays an important role in the malignant transformation process leading to HCC and that it is closely related to the histological grade of HCC. HCC would offer a novel tool with which to study the function of AX-I in malignant transformation.