Stable carbamate pathway towards organic-inorganic hybrid perovskites and aromatic imines.

Methyl ammonium methyl carbamate (MAC), formulated as CH3NH3 +CH3NHCO2 -, was synthesized by reacting liquid methylamine with supercritical CO2, and its structure was refined by single-crystal X-ray diffraction. MAC is a white crystalline salt and is as reactive as methylamine, and is a very efficient alternative to toxic methylamine. We were able to produce hybrid perovskite MAPbI3 (MA = methyl ammonium) by grinding MAC with PbI2 and I2 at room temperature, followed by storing the mixed powder. Moreover, this one-pot method is easily scalable for the large-scale synthesis of MAPbI3 in a small vessel. We have also investigated the reactivity of MAC towards aromatic aldehydes in the absence of solvent. The solventless reactions afforded imines as exclusive products with over 97% yield, which show higher selectivity than the methylamine-based synthesis. Complete conversions were typically accomplished within 3 h at 25 °C. The results of this study emphasize the importance of solid carbamates such as MAC to develop an environmentally friendly process for the synthesis of various amine-based materials on the industrial scale.

Effect of Oxygen on the Structural/Electrical Properties of NIZO Films on Transparent Flexible Substrates.

Thin film transparent oxides have attracted considerable attention over the last few decades for transparent electronic applications, such as flat panel displays, solar cells, touch-pads, and mobile devices. Metallic doped InZnO (IZO) films have been suggested for the transparent layer exhibiting semiconducting or metallic properties because of its controllable mobility and excellent electrical properties, but they show a degradation of the electrical performance under bending conditions. This study assessed Ni doped IZO (NIZO) films as a flexible transparent electrode on different flexible transparent substrates for flexible electronic applications. Thin NIZO films were deposited on cellulose, PES and glass substrates using a sputtering system with a single NIZO target (In2O3 73.8/ZnO 15.7/NiO 10.5 mol.%) at room temperature. During deposition of the NIZO films, the total flow rate of the carrier gas was maintained using a regulating system. The effects of the oxygen content in the carrier gas on the structural, electrical and optical properties of the thin films deposited on flexible substrates was characterized. The results highlight the feasibility of the transparent NIZO oxide layer on flexible substrates as a flexible electrode with a relatively high sheet resistance, which is strongly related to the crystallographic structure and oxygen content during the film deposition process.

Controlled synthesis of monodisperse SiO(2)--TiO(2) microspheres with a yolk-shell structure as effective photocatalysts.

Monodisperse yolk-shell SiO(2) -TiO(2) microspheres were synthesized using core-shell silica microspheres as templates. In the absence of prior surface modifications, a uniform coating of the TiO(2) layer on the core-shell silica was achieved through a sol-gel route. Mesoporous silica shells between the outer TiO(2) shell and the SiO(2) core were selectively removed by using a weak base, yielding yolk-shell SiO(2) -TiO(2) microspheres (ys-SiO(2) @TiO(2) ). Using the same templates, we synthesized Pt-encased microspheres (SiO(2) @Pt-TiO(2) ), in which Pt nanoparticles are embedded between the SiO(2) core and the TiO(2) shell. Selective etching of the silica shells in SiO(2) @Pt-TiO(2) yields Pt-encased yolk-shell SiO(2) -TiO(2) microspheres (ys-SiO(2) @< Pt >TiO(2) ), which contain void spaces suitable for use as nanoreactors. The ys-SiO(2) @< Pt >TiO(2) catalyst shows enhanced hydrogen production from water under UV-light irradiation presumably as a result of multiple reflections within the void spaces and can be reused without losing their activity. Moreover, this core-shell template method is effective for the synthesis of other yolk-shell microspheres with different metal oxides.

Thin transparent W-doped indium-zinc oxide (WIZO) layer on glass.

Annealing effect on structural and electrical properties of W-doped IZO (WIZO) films for thin film transistors (TFT) was studied under different process conditions. Thin WIZO films were deposited on glass substrates by RF magnetron co-sputtering technique using indium zinc oxide (10 wt.% ZnO-doped In2O3) and WO3 targets in room temperature. The post annealing temperature was executed from 200 degrees C to 500 degrees C under various O2/Ar ratios. We could not find any big difference from the surface observation of as grown films while it was found that the carrier density and sheet resistance of WIZO films were controlled by O2/Ar ratio and post annealing temperature. Furthermore, the crystallinity of WIZO film was changed as annealing temperature increased, resulting in amorphous structure at the annealing temperature of 200 degrees C, while clear In2O3 peak was observed for the annealed over 300 degrees C. The transmittance of as-grown films over 89% in visible range was obtained. As an active channel layer for TFT, it was found that the variation of resistivity, carrier density and mobility concentration of WIZO film decreased by annealing process.

[Primary malignant fibrous histiocytoma (MFH) of the small bowel presenting as an intussusception causing small bowel obstruction].

Adult intussusception secondary to primary sarcoma is a rare cause of small bowel obstruction. Only a few cases of malignant fibrous histiocytoma (MFH) of small bowel presenting as an intussusception have been reported in the literatures. We report a case of small bowel obstruction associated with jejuno-ileal intussusception caused by MFH. A 75-year-old man was admitted with an one-month history of vomiting and epigastric pain aggravated with meals. He was diagnosed as an jejuno-ileal intussusception based on CT scanning and underwent small bowel resection and anastomosis. Resected specimens revealed a polypoid tumor in the ileum and the histology of the tumor was consistent with MFH.