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.

A Novel Reactive Polymeric Micelle with Aldehyde Groups on Its Surface

Abstract: It is reported that amphiphilic AB block copolymers form in selective solvents micellar structures.' These nanospheric particles combine the advantages given by the hydrophobic core, which can act as a vehicle for medical drugs, and the unique properties of a hydrophilic ~ h e 1 1 . ~ ~ PEO chains attached to a surface or forming the corona of a nanospheric particle in an aqueous medium exhibit rapid chain motions and have a large excluded volume. The steric repulsion resulting from a loss of configurational entropy of the bound PEO upon the approach of a foreign particle and the low interfacial free energy contribute to the extraordinary properties of PEO-covered surface^.^-'^ The small size, apparent thermodynamic stability, and exceptional biological features of polymeric micelles favor their application in the biomedical field.11-14 Recently, a facile and quantitative synthetic method for the formation of heterobifunctional poly(ethy1ene oxide) was reported.15J6 If one of the functional end groups in the heterobifunctional PEO can selectively initiate the polymerization of a hydrophobic monomer, a new heterobifunctional AB block copolymer can be created, retaining the other functional group (acetal group) a t the PEO chain end. As a core-forming segment, polylactide (PLA) was chosen for the following reasons: (1) The ring-opening reaction of a lactide can be initiated by the living chain end of potassium ethylene oxide without any side reaction. (ii) PLAS are biodegradable and nontoxic polymers, which are widely utilized as implant materials. This is an important prerequisite considering a future application of this system in the biomedical field. (iii) Nanoparticles, consisting of block copolymers of a-methoxypoly(ethy1ene oxide) and PLA are suited for drug de1i~ery.l~ Furthermore, the micelle formation and transformation of acetal into aldehyde groups on the micelle surface were discussed. An aldehyde group reacts rapidly with primary amino groups, forming a Schiff base, a chemical path which could be employed in the hture for conjugations with proteins. Experimental Section. Materials and Methods. Commercial tetrahydrofuran (THF), 3,3-diethoxypropanol, ethylene oxide (EO), and lactide were purified conventionally.l8 Potassium naphthalene was used as a THF solution.1g GPC measurements were carried out using a Shimadzu 6A liquid chromatograph equipped with a PEO-calibrated TSK gel column (G4000HXL, G3000HXL, G2500HXL) and an internal RI detector (RID-6A). THF containing 2% of triethylamine was used as eluent a t a flow rate of 1 mumin. 'H-NMR

Identification of 45 new neutron-rich isotopes produced by in-flight fission of a 238 U beam at 345 MeV/nucleon

Abstract: A search for new isotopes using in-flight fission of a 345 MeV/nucleon 238 U beam has been carried out at the RI Beam Factory at the RIKEN Nishina Center. Fission fragments were analyzed and identi...

Photoelectrochemical Hydrogen Peroxide Production from Water on a WO3 /BiVO4 Photoanode and from O2 on an Au Cathode Without External Bias.

Abstract: The photoelectrochemical production and degradation properties of hydrogen peroxide (H2O2) were investigated on a WO3/BiVO4 photoanode in an aqueous electrolyte of hydrogen carbonate (HCO3−). High concentrations of HCO3− species rather than CO32− species inhibited the oxidative degradation of H2O2 on the WO3/BiVO4 photoanode, resulting in effective oxidative H2O2 generation and accumulation from water (H2O). Moreover, the Au cathode facilitated two-electron reduction of oxygen (O2), resulting in reductive H2O2 production with high current efficiency. Combining the WO3/BiVO4 photoanode with a HCO3− electrolyte and an Au cathode also produced a clean and promising design for a photoelectrode system specializing in H2O2 production (ηanode(H2O2)≈50 %, ηcathode(H2O2)≈90 %) even without applied voltage between the photoanode and cathode under simulated solar light through a two-photon process; this achieved effective H2O2 production when using an Au-supported porous BiVO4 photocatalyst sheet.

DNA damage response in plants: conserved and variable response compared to animals.

Abstract: The genome of an organism is under constant attack from endogenous and exogenous DNA damaging factors, such as reactive radicals, radiation, and genotoxins. Therefore, DNA damage response systems to sense DNA damage, arrest cell cycle, repair DNA lesions, and/or induce programmed cell death are crucial for maintenance of genomic integrity and survival of the organism. Genome sequences revealed that, although plants possess many of the DNA damage response factors that are present in the animal systems, they are missing some of the important regulators, such as the p53 tumor suppressor. These observations suggest differences in the DNA damage response mechanisms between plants and animals. In this review the DNA damage responses in plants and animals are compared and contrasted. In addition, the function of SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), a plant-specific transcription factor that governs the robust response to DNA damage, is discussed.