Keramadine,a novel antagonist of serotonergic receptors isolated from the okinawan sea sponge Agelas sp.

A new bromine-containing alkaloid, keramadine, has been isolated from the Okinawan sea sponge Agelas sp. as a novel antagonist of serotonergic receptors and its structure has been elucidated by n.m.r. spectrometry.     

PHYTOCHROME SYNTHESIS DURING IMBIBITION IN EMBRYONIC AXES OF Pisum sativum L.*

Abstract— The exact quantity of phytochrome in crude homogenates (2kS) prepared from embryonic axes of Pisum sativum during imbibition at 25°C on 0,2% agar was estimated optically. The problem of the scattering factor was solved by using highly purified phytochrome as an internal standard. The content of phytochrome protein moiety in diluted samples of the crude homogenates of the axes was also determined by an enzyme-linked immunosorbent assay (ELISA). Phytochrome was not detectable either spectropho-tometrically or immunochemically in 2kS of dormant dry axes. Embryonic axes quickly absorbed water during the first1–2 h after the start of imbibition, after which the fresh weight stayed at a constant level for a further 10 h. The content of spectrophotometrically detectable phytochrome increased during imbibition in the dark, reaching about 0.2 μ.g/axis after 12 h. The amount of phytochrome in 2kS of axes in the light was so small that only about 0.05 μg/axis was detected after 12 h. The content of immunochemically detectable phytochrome greatly increased up to ca. 0.5 μg/axis after 12 h of dark incubation. In 2kS of the light-grown axes the content of the phytochrome protein was ca. one fourth lower than in dark-grown axes. We conclude that the appearance and increase of phytochrome in fragments of imbibed embryonic axes were caused by de novo synthesis and that the contents of both photometrically detectable phytochrome and its protein moiety in the light-grown samples were lower than those in the dark throughout the early germination process.     

Solution space of discrete Wiener-Hopf equations and Grassmann manifold

It is shown that the solution space of a system of discrete Wiener-Hopf equations is a set of points on an infinite-dimensional Grassmann manifold. Fractional transformations acting on the solution space are also discussed.     

Transformation of resonant Raman scattering into luminescence in CdxZn1−xTe mixed crystals: Time-resolved spectroscopy

We report an experimental study of time characteristics of secondary emission in Cd_xZn_1-xTe mixed crystals (x = 0.32) under resonant excitation with a picosecond dye laser. When the incident laser frequency is tuned on to the luminescence maximum of localized excitons, the decay curve of the intensity of “Raman-like” lines exhibits a single exponential decay. Off resonance, however, a short-lived component corresponding to Raman scattering appears in addition to the long-lived component. The intensity of the Raman component relative to that of the luminescence component increases with increase of the off-resonance frequency. From these temporal behaviors, we have found, for the first time, the transformation of resonant Raman scattering into luminescence in mixed crystals as a function of incident frequencies.     

Analytical and numerical studies of angular correlation function of waves scattered from randomly distributed cylinders

The analytical solution for the angular correlation function of scattered waves from randomly distributed infinitely long cylinders is obtained using the second-order approximation with a modified attenuation coefficient. The approach is based on the coherent summation of the scattered waves which preserves the interference effects such as backscattering enhancement. The modification of the transport attenuation coefficient includes the contribution due to the incoherent wave. By comparing with the exact numerical simulations, we found that the correction factor is given by (1-μ¯) which also appears in the diffusion equation. The present approach gives good agreement with numerical and experimental results.     

A novel cyclization reaction of oxidodiazoalkanes: formation of pyrazoles and pyridazines

The thermal decomposition of dialkali metal salts of β- and γ-hydroxyketone tosyl-hydrazones in refluxing DME produced pyrazoles and pyridazines, respectively.     

Synthesis and complexation of a novel cyclophane

A novel cyclophane, 17, 17, 40, 40-tetramethyl-7, 30-dinitro-1, 10, 24, 33-tetraoxa[2.2.1.2.2.1] metaparaparametaparaparacyclophane, was synthesized by 2:2 cyclization of 3,5-bis(bromomethyl)nitrobenzene, derived from 3,5-dimethylnitrobenzene, and bisphenol A. The cyclophane was found to form 1:1 complex with benzene.     

Mössbauer study of amorphous Fe2RE (RE=Ce,Er) alloys

Among amorphous Fe₂RE (RE=Er, Ce, Gd, La, Pr, Sm, Dy, Ho) alloys, Fe₂Ce exhibits a tendency toward short range order, while the other Fe₂RE compounds show clustering. However, we have almost no information about environments around Fe atoms. Using Mössbauer spectroscopy we have determined the quadrupole splitting distributionsP(QS) of two representative amorphous Fe₂RE (RE=Ce, Er) alloys, leading to local environments of Fe atoms. The analysis of the mixed magnetic dipole and quadrupole interactions in Fe₂Er shows two kinds of electrical field gradients (EFT) with the positive and negative signs in the sample, indicating a random packing of Fe atoms. Furthermore, the analyzed quadrupole splitting distributionP(QS) of Fe₂Er also supports random packing in this amorphous alloy. On the other hand, the amorphous Fe₂Ce alloy shows two kinds of distributions of quadrupole splitting; the major component indicating random packing and the minor component Ce-rich Ce-Fe clusters.     

Selective cleavage of ethers by sodium iodide-acyl chloride

Cyclic and acyclic ethers are regioselectively cleaved at less substituted α-carbon-oxygen bond in the absence of Lewis acid by the reagent system of sodium iodide and acyl chlorides.