Cytotoxic substances from two species of Japanese sea hares: chemistry and bioactivity

From the sea hares belonging to two genera, Aplysia and Dolabella, a variety of new cytotoxic substances were isolated as minute constituents: their chemical structures were determined and their cytotoxicity was evaluated. Regarding the highly cytotoxic substances, further chemical and biological studies were performed that included their asymmetric chemical synthesis and elucidation of biological characteristics such as antitumor activity.     

Unconventional pairing originating from disconnected Fermi surfaces in the iron-based superconductor

For the iron-based high T_c superconductor LaFeAsO_1?xF_x, we construct a minimal model, where all of the five Fe d bands turn out to be involved. We then investigate the origin of superconductivity with a five-band random-phase approximation by solving the Eliashberg equation. We conclude that the spin fluctuation modes arising from the nesting between the disconnected Fermi pockets realise, basically, an extended s-wave pairing, where the gap changes sign across the nesting vector.     

Synthesis of a tripalladium cluster containing an η:η:η-bridging butadienyl ligand stabilized by a zwitterionic structure

An η¹-butadienyl complex [trans-η¹-CH₂=C(Me)C=CH₂Pd(PPh₃)₂Cl] (1) reacted with [(μ-η²:η²-1,3-butadiene)Pd₂(PPh₃)(μCl)Cl] (2) to result in displacement of the diene ligand of 2 accompanied by exchange of PPh₃ of 1 with Cl anion of 2 producing a butadienyl tripalladium cluster [(μ-CH₂=C(Me)C=CH₂)Pd(PPh₃)Cl₂ · Pd₂(PPh₃)₂(μ-Cl)] (3) stabilized by the zwitterionic structure in moderate yield. The X-ray structure analysis of 3 revealed rigid binding of [Pd₂(PPh₃)₂(μ-Cl)]⁺ and [CH₂ =C(Me)C=CH₂Pd(PPh₃)Cl₂]⁻ through the π-bond coordination of the butadienyl group to the dipalladium cation.     

Paramagnetic Inversion of the Sign of the Interference Contribution to the Transverse Relaxation of the Imido Protons of the Coordinated Imidazoles in the UniformlyN-Labeled Cytochromec3

In the spectrum of uniformly¹⁵N-labeled cytochromec₃, the relative linewidths of the doublet peaks of the¹⁵N-coupled imido proton of the coordinated imidazole group were reversed on oxidation. This inversion was explained by the interference relaxation process between the electron–proton dipolar and¹⁵N–¹H dipolar interactions. The inversion can be used to assign the imido protons of the coordinated imidazole groups in heme proteins.     

Arrangement of fullerene above the poly(methyl methacrylate) surface with fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide polymers

Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide polymers were found to be a convenient tool for the arrangements of fullerenes above the poly(methyl methacrylate) [PMMA] surface, and the higher fluorescent intensity of fullerene was obtained in the modified PMMA surface, although the reverse side of this modified film surface afforded an extremely weak fluorescent intensity.     

Optical Differentiation Phase Measurement Using the Bias Shifting Method

A new optical phase measurement method using a differentiation filter is proposed. The new method uses two images obtained by shifting the filter. This method has an advantage in that non-uniformity of the wavefront intensity does not produce errors. We present herein the theory of the newly proposed method and verify the theory by computer simulation. The effects of non-uniformity of the wavefront intensity, noise, and bias shifting length for errors are discussed. The system has been demonstrated for a plane wave and a spherical wave. For the proposed method, although the number of errors due to noise increases, the number of errors due to non-uniformity decreases. Therefore, the proposed method is useful for the phase measurement of a wavefront for which the intensity is not uniform. In addition, it improves the accuracy of the phase measurement system using a differentiation filter.