Osaka University

About: Osaka University is a education organization based out in Osaka, Japan. It is known for research contribution in the topics: Laser & Catalysis. The organization has 83778 authors who have published 185669 publications receiving 5158122 citations. The organization is also known as: Ōsaka daigaku.

Hepatocyte growth factor gene therapy of liver cirrhosis in rats.

Abstract: Liver cirrhosis is the irreversible end result of fibrous scarring and hepatocellular regeneration, characterized by diffuse disorganization of the normal hepatic structure of regenerative nodules and fibrotic tissue. It is associated with prominent morbidity and mortality, and is induced by many factors, including chronic hepatitis virus infections, alcohol drinking and drug abuse. Hepatocyte growth factor (HGF), originally identified and cloned as a potent mitogen for hepatocytes, shows mitogenic, motogenic and morphogenic activities for a wide variety of cells. Moreover, HGF plays an essential part in the development and regeneration of the liver, and shows anti-apoptotic activity in hepatocytes. In a rat model of lethal liver cirrhosis produced by dimethylnitrosamine administrations, repeated transfections of the human HGF gene into skeletal muscles induced a high plasma level of human as well as enodogenous rat HGF, and tyrosine phosphorylation of the c-Met/HGF receptor. Transduction with the HGF gene also suppressed the increase of transforming growth factor-beta1 (TGF-beta1), which plays an essential part in the progression of liver cirrhosis, inhibited fibrogenesis and hepatocyte apoptosis, and produced the complete resolution of fibrosis in the cirrhotic liver, thereby improving the survival rate of rats with this severe illness. Thus, HGF gene therapy may be potentially useful for the treatment of patients with liver cirrhosis, which is otherwise fatal and untreatable by conventional therapy.

Mechanistic Insight into the TiO2 Photocatalytic Reactions: Design of New Photocatalysts

Abstract: Titanium dioxide (TiO2) has been extensively investigated for the photocatalytic purification of air and water. In this article, we have focused on the mechanisms of the one-electron redox reactions of organic compounds during the TiO2 photocatalytic reactions and on the development of TiO2-based materials. It was clearly demonstrated that the adsorption dynamics of substrates and intermediates, the electronic interaction between TiO2 and adsorbates, and the band structure and morphology of TiO2 nanomaterials are crucial factors for establishing efficient photocatalytic reaction systems. The TiO2-based hybrid nanoparticles with various functional materials, such as polyoxometalates (POMs) and cyclodextrins (CDs), have been fabricated on the basis of the mechanistic aspects. New experimental methods, such as two-color two-laser flash photolysis and single-molecule fluorescence techniques, for the investigation of the TiO2 photocatalytic reactions have been demonstrated.

Mechanism for Visible Light Responses in Anodic Photocurrents at N-Doped TiO2 Film Electrodes

Abstract: Nitrogen doping of anatase TiO2 powder extended the photocurrent action spectrum for water oxidation from the UV-light region (≤400 nm) to the visible-light region (≤ ∼550 nm), as reported. Investigations of the effect of the addition of reductants such as methanol, SCN-, Br-, I-, and hydroquinone to the electrolyte have for the first time given clear experimental evidence to the mechanism that visible-light responses for N-doped TiO2 arise from an N-induced midgap level, formed slightly above the top of the (O-2p) valence band. The investigations, in combination with the above mechanism, have also shown that photocatalytic oxidation of organic compounds on N-doped TiO2 under visible illumination mainly proceed via reactions with surface intermediates of water oxidation or oxygen reduction, not by direct reactions with holes trapped at the N-induced midgap level.