Anisotropic catalytic activity of the orientation controlled Nd2NiO4 + δ/YSZ hetero-epitaxial system for SOFC cathode

Electrode–electrolyte hetero-epitaxial systems for solid oxide fuel cells (SOFCs) with two different configuration of Nd₂NiO_4 + δ(110)//YSZ(100) and Nd₂NiO_4 + δ(100)//YSZ(110) were successfully fabricated by pulsed laser deposition. Thin films of Nd₂NiO_4 + δ approximately 20 nm thick were grown on a commercial single crystal of YSZ. The preferred two-dimensional diffusion paths of the oxide ions were perpendicular to the substrate for both configurations and showed oxygen reduction capability different from each other. This opens up new research direction focusing on the details of anisotropic catalytic activity of SOFC cathode depending on the crystalline surface.     

Novel acyl alpha-pyronoids, dictyopyrone A, B, and C, from Dictyostelium cellular slime molds

For the elucidation of the diversity of secondary metabolites of Dictyostelium cellular slime molds, we investigate the constituent of three species of slime molds. From the methanol extract of their fruit bodies, we obtained three novel compounds, dictyopyrone A (1) and B (2) from D. discoideum and D. rhizoposium and dictyopyrone C (3) from D. longosporum. They possess a unique alpha-pyrone moiety with a side chain at the C-3 position. Their relative structures were elucidated by spectral means, and the absolute configuration was confirmed by asymmetric synthesis of 1. Since these compounds were obtained from different species of Dictyostelium slime molds, they may be a type of compound common to this genus.     

Studies on the constituents of Lonicera species. XVII. New iridoid glycosides of the stems and leaves of Lonicera japonica THUNB

Four new iridoid glycosides, named L-phenylalaninosecologanin (1), 7-O-(4-beta-D-glucopyranosyloxy-3-methoxybenzoyl)secologanolic acid (2), 6'-O-(7alpha-hydroxyswerosyloxy)loganin (3) and (Z)-aldosecologanin (5), were isolated, together with a known one, newly named (E)-aldosecologanin (4), from the stems and leaves of Lonicera japonica. Their structures were established on the basis of chemical and spectral data.     

Nonspecific medium effects versus specific group positioning in the antibody and albumin catalysis of the base-promoted ring-opening reactions of benzisoxazoles

The mechanisms by which solvents, antibodies, and albumins influence the rates of base-catalyzed reactions of benzisoxazoles have been explored theoretically. New experimental data on substituent effects and rates of reactions in several solvents, in an antibody, and in an albumin are reported. Quantum mechanical calculations were carried out for the reactions in water and acetonitrile, and docking of the transition state into a homology model of antibody 34E4 and an X-ray structure of human serum albumin was accomplished. A microenvironment made up of catalytic polar groups (glutamate in antibody 34E4 and lysine in human serum albumin) surrounded by relatively nonpolar groups is present in both catalytic proteins.     

Novel trichothecanes, paecilomycine A, B, and C, isolated from entomopathogenic fungus, Paecilomyces tenuipes

Paecilomycine A (1), B (2), and C (3) were isolated from cultivated fruiting bodies of Paecilomyces tenuipes (Isaria japonica), which is a popular entomopathogenic fungus used in folk medicine and health foods in China, Korea, and Japan. The structures of 1-3 were deduced from their spectroscopic data and their absolute configurations were elucidated by preparing their MPA esters. Compound 1 showed activity in the neurotrophic factor biosynthesis in glial cells.     

Cerasome as an Organic-Inorganic Vesicular Nanohybrid: Characterization of Cerasome-Forming Lipids having a Single or a Dual Trialkoxysilyl Head

Morphological characterization of the organic-inorganic vesicular nanohybrids, Cerasomes, was performed in aqueous media from two aspects. Firstly, a novel Cerasome-forming lipid having two triethoxysilyl groups in the head moiety was synthesized and the physical property of the Cerasome was investigated. While the morphological stability of the Cerasomes, as evaluated from the vesicular collapse behavior against a micelle-forming nonionic surfactant, Triton-X 100, was extremely higher than that of the conventional phospholipid liposome, the stabilities were comparable to each other for the Cerasomes derived from the dual- and single-head lipids. On the other hand, the surface property of the Cerasome formed with the dual-head lipid more closely resembled the colloidal silica particles rather than that derived from the single-head lipid, as suggested by zeta-potential measurements. Secondly, the effect of the media pH on the morphological stability of the Cerasome formed with the single-head lipid was evaluated and appeared as a time difference in obtaining the morphological stability of the Cerasome. These morphological characteristics of the Cerasomes could be mainly owing to the development of the siloxane network on the vesicular surface.     

Long-term effects of UV light on contractility of rat arteries in vivo

Several studies have shown that UV irradiation may be effective for preventing vascular restenosis or vasopasm. However, the long-term effects of UV light on the physiological properties of vessels such as arterial tension have not been elucidated. We therefore studied the long-term effects of UV using rat carotid arteries treated with UV-B light (wavelength = 313 nm, total energy = 14 mJ/mm2). The animals were sacrificed at 1, 7 and 14 days after UV light exposure, and the carotid arteries were studied by light microscopy and the contractile responses of isolated arterial rings were recorded under isometric tension. UV treatment had induced a substantial loss of smooth muscle cells (SMC) along the entire circumference of the media on days 7 and 14, whereas loss of SMC on day 1 was negligible. Contractile responses of arteries that had been exposed to UV light were significantly reduced on days, 1, 7 and 14. The susceptibility of UV-treated arteries to phenylephrine and prostaglandin F2 alpha was significantly decreased on days 1 and 7, but decreased susceptibility was not seen on day 14. Acetylcholine-induced relaxations were not altered by UV treatment. These results suggest that the long-term effect of UV light is an attenuation of smooth muscle contractility without impairment of endothelial function.     

Selective Generation of Formamides through Photocatalytic CO2 Reduction Catalyzed by Ruthenium Carbonyl Compounds

The selective formation of dialkyl formamides through photochemical CO₂ reduction was developed as a means of utilizing CO₂ as a C₁ building block. Photochemical CO₂ reduction catalyzed by a [Ru(bpy)₂(CO)₂]²⁺ (bpy: 2,2′‐bipyridyl)/[Ru(bpy)₃]²⁺/Me₂NH/Me₂NH₂⁺ system in CH₃CN selectively produced dimethylformamide. In this process a ruthenium carbamoyl complex ([Ru(bpy)₂(CO)(CONMe₂)]⁺) formed by the nucleophilic attack of Me₂NH on [Ru(bpy)₂(CO)₂]²⁺ worked as the precursor to DMF. Thus Me₂NH acted as both the sacrificial electron donor and the substrate, while Me₂NH₂⁺ functioned as the proton source. Similar photochemical CO₂ reductions using R₂NH and R₂NH₂⁺ (R=Et, nPr, or nBu) also afforded the corresponding dialkyl formamides (R₂NCHO) together with HCOOH as a by‐product. The main product from the CO₂ reduction transitioned from R₂NCHO to HCOOH with increases in the alkyl chain length of the R₂NH. The selectivity between R₂NCHO and HCOOH was found to depend on the rate of [Ru(bpy)₂(CO)(CONR₂)]⁺ formation.