Photoreaction of anthracenyl phosphine oxides: Usual reversible photo- and heat-induced emission switching,and unusual oxidative PC bond cleavage

Anthracenyl(diphenyl)phosphine oxide and dianthracenylphenylphosphine oxide as photoactive compounds have been synthesized. Anthracenyl group of these compounds indicate the multi-functional roles such as an emission component, a photodimerization component, and a leaving group. When the light irradiation was performed under an oxygen atmosphere, photo-oxidative PC bond cleavage to leave the antharacenyl group was observed. Moreover, phosphonyl radical was produced and then PP bond formation to form diphosphane was observed.     

Identification of a regulatory element for yeast tryptophan permease Tat2 ubiquitination using high hydrostatic pressure

ABSTRACT

Tryptophan uptake in the yeast Saccharomyces cerevisiae is extremely sensitive to high pressure; therefore, the growth of tryptophan auxotrophic strains is impaired. Degradation of tryptophan permease Tat2 is enhanced at 25?MPa, depending on Rsp5 ubiquitin ligase. Any defect in Tat2 ubiquitination confers high pressure growth capacity, which is a luminous phenotype of the yeast used to explore the mechanism by which Rsp5 mediates Tat2 ubiquitination. Here we show that the N-terminal four (K17, K20, K29, and K31) among five lysines are required for efficient Tat2 degradation under high pressure. We found that a domain spanning D70 to S76 is also critical for Tat2 degradation at 25?MPa probably because of the recognition by Bul1, an adaptor protein of Rsp5. Defects in Tat2 ubiquitination do not produce any remarkable mutant phenotype at 0.1?MPa. Therefore, we suggest that high pressure is a unique and advanced tool to explore ubiquitination-dependent Tat2 regulation.     

Multicycle Indentation for Evaluation of Polymer Material Viscoelastic Characteristics

The evaluation of viscoelastic characteristics by an indentation test is required in order to separate the viscoelastic deformation and plastic deformation from the measured penetration depth. In this study, a multicycle indentation test is performed in order to separate these deformations and to evaluate the viscoelastic characteristics of acrylonitrile butadiene styrene (ABS) and polybutylene terephthalate (PBT). In the multicycle indentation test, two or more indentation tests are conducted at the same specimen position. After the first cycle, the indentation test is performed on the impression; thus, an evaluation formula for obtaining the viscoelastic characteristics is proposed, and the validity of this formula is confirmed by finite element analysis. As a result, the evaluated creep compliances of both materials are close the value evaluated by tensile testing. Therefore, it is concluded that the proposed method is applicable to the evaluation of viscoelastic characteristics.     

Cinchona–diaminomethylenemalononitrile organocatalyst for asymmetric conjugate addition of 1,3-diketone to nitroalkene

A diaminomethylenemalononitrile organocatalyst with a cinchona motif efficiently promotes the enantioselective conjugate addition of acetylacetone to various nitroalkenes to yield the corresponding addition products in high to excellent yields with up to 89% ee.