Tokyo University of Science

About: Tokyo University of Science is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Thin film & Enantioselective synthesis. The organization has 15800 authors who have published 24147 publications receiving 438081 citations. The organization is also known as: Tōkyō Rika Daigaku & Science University of Tokyo.

The Physics of the B Factories

Abstract: This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C.

Involvement of human organic anion transporting polypeptide OATP-B (SLC21A9) in pH-dependent transport across intestinal apical membrane

Abstract: Some organic anions are absorbed from the gastrointestinal tract through carrier-mediated transport mechanism(s), which may include proton-coupled transport, anion exchange transport, and others. However, the molecular identity of the organic anion transporters localized at the apical membrane of human intestinal epithelial cells has not been clearly demonstrated. In the present study, we focused on human organic anion transporting polypeptide OATP-B and examined its subcellular localization and functionality in the small intestine. Localization of OATP-B was determined by immunohistochemical analysis. Transport properties of estrone-3-sulfate and the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor pravastatin by OATP-B-transfected human embryonic kidney 293 cells were measured. OATP-B was immunohistochemically localized at the apical membrane of intestinal epithelial cells in humans. Uptake of [3H]estrone-3-sulfate and [14C]pravastatin by OATP-B at pH 5.5 was higher than that at pH 7.4. [3H]Estrone-3-sulfate transport was decreased by pravastatin, aromatic anion compounds, and the anion exchange inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, but not by small anionic compounds, such as lactic acid and acetic acid. The inhibitory effect of pravastatin on the uptake of [3H]estrone-3-sulfate was concentration-dependent, and the IC50 value was 5.5 mM. The results suggested that OATP-B mediates absorption of anionic compounds and its activity may be optimum at the acidic surface microclimate pH of the small intestine. Accordingly, OATP-B plays a role in the absorption of anionic compounds across the apical membrane of human intestinal epithelial cells, although it cannot be decisively concluded that pH-dependent absorption of pravastatin is determined by OATP-B alone.

Copolymerization of carbon dioxide and epoxide

Abstract: Alternating copolymerization of CO2 and epoxide to give aliphatic polycarbonate with high molecular weight proceeds under mild conditions by organometallic catalyst systems. The reaction product of diethylzinc with a polyhydric compound, such as water or polyhydric phenol, exhibits high catalytic activity. Elementary reactions for the copolymerization of CO2 and epoxide with an organozinc catalyst system is considered to be the reaction of a zinc alkoxide with CO2 to form a zinc alkyl carbonate, and the reaction of the zinc alkyl carbonate with epoxide to regenerate zinc alkoxide. The system of aluminum porphyrin such as (tetraphenylporphinato)aluminum chloride, coupled with a quaternary ammominum or phosphonium salt, such as ethyltriphenylphosphonium bromide, is a good catalyst for this copolymerization. Of much interest is the very narrow molecular weight distribution of the copolymer obtained by this system. Aluminum porphyrin and the quaternary salt forms a hexa-coordinate complex, and the copolymerization reaction is considered to proceed on both sides of the porphyrin ring. Some properties of the copolymer for possible application are described.