Improved optical potential for low and medium energy π−-4He elastic scattering

Effects of the second-order correction in multiple scattering theory and the nucleon binding correction to the optical potential are investigated in π^?-⁴He elastic scattering and total reaction cross-sections. The second-order correction includes not only nucleon-nucleon correlation effects but also the contribution from spin (isospin) double-flip processes. It is found that the latter has an ascendency over the former. We have also shown that the nucleon binding effect is very important to reproduce the energy dependence of the total elastic cross section and the total reaction cross section, especially in the low energy and resonance energy regions.     

Heats of pyridine intercalation with α- and γ-zirconium phosphates

Calorimetric measurements at 25°C were made to determine the thermodynamic quantities for the intercalation of pyridine with α- and γ-zirconium phosphates. These phosphates showed exothermic reactions with ΔH⁰ = ?59.3 and ?21.9 kJ mole^?1, respectively. The large difference between the depyridination temperatures for both intercalates is rediscussed with the aid of the ΔG⁰ data obtained.     

Substituent effects of iridium complexes for highly efficient red OLEDs

This study reports substituent effects of iridium complexes with 1-phenylisoquinoline ligands. The emission spectra and phosphorescence quantum yields of the complexes differ from that of tris(1-phenylisoquinolinato-C2,N)iridium(iii)(Irpiq) depending on the substituents. The maximum emission peak, quantum yield and lifetime of those complexes ranged from 598-635 nm, 0.17-0.32 and 1.07-2.34 micros, respectively. This indicates the nature of the substituents has a significant influence on the kinetics of the excited-state decay. The substituents attached to phenyl ring have an influence on a stability of the HOMO. Furthermore, those substituents have effect on the contribution to a mixing between 3pi-pi* and (3)MLCT for the lowest excited states. Some of the complexes display the larger quantum yield than Irpiq, which has the quantum yield of 0.22. The organic light emitting diode (OLED) device based on tris [1-(4-fluoro-5-methylphenyl)isoquinolinato-C2,N]iridium(iii)(Ir4F5Mpiq) yielded high external quantum efficiency of 15.5% and a power efficiency of 12.4 lm W(-1) at a luminance of 218 cd m(-2). An emission color of the device was close to an NTSC specification with CIE chromaticity characteristics of (0.66, 0.34).     

Application of sequence Fourier analysis to a specific interaction in Arabidopsis thaliana

The sequence Fourier analysis reported previously seems to be applicable to elucidating a simple and concerted interaction in Arabidopsis thaliana, similar to that in Homo sapiens.     

Amphidinolide Y, a novel 17-membered macrolide from dinoflagellate Amphidinium sp.: plausible biogenetic precursor of amphidinolide X

A novel cytotoxic 17-membered macrolide, amphidinolide Y (1), has been isolated from a marine dinoflagellate Amphidinium sp., and it was elucidated to exist as a 9:1 equilibrium mixture of 6-keto- and 6(9)-hemiacetal forms (1a and 1b, respectively) on the basis of 2D NMR data and chemical means. The feeding experiments with (13)C-labeled acetates suggested that amphidinolide Y (1) may be a biogenetic precursor of 16-membered macrodiolide, amphidinolide X (2).     

Plakevulin A, a new oxylipin inhibiting DNA polymerases α and γ from sponge Plakortis species

A new cytotoxic oxylipin, plakevulin A (1), possessing a cyclopentene ring and a levulinyl ester has been isolated from an Okinawan marine sponge Plakortis sp. The structure was elucidated on the basis of spectroscopic data, and the absolute configurations at three chiral centers were assigned by spectroscopic data of the reductive product of 1 and a modified Mosher's method. Plakevulin A (1) exhibited inhibitory activity against DNA polymerases α and γ.     

A novel action of terpendole E on the motor activity of mitotic Kinesin Eg5

To reveal the mechanism of mitosis, the development of M phase-specific inhibitors is an important strategy. We have been screening microbial products to find specific M phase inhibitors that do not directly target tubulins, and rediscovered terpendole E (TerE) as a novel Eg5 inhibitor. TerE did not affect microtubule integrity in interphase, but induced formation of a monoastral spindle in M phase. TerE inhibited both motor and microtubule-stimulated ATPase activities of human Eg5, but did not affect conventional kinesin from either Drosophila or bovine brain. Although terpendoles have been reported as inhibitors of acyl-CoA:cholesterol O-acyltransferase (ACAT), the Eg5 inhibitory activity of TerE was independent of ACAT inhibition. Taken together, we demonstrate that TerE is a novel Eg5 inhibitor isolated from a fungal strain.