New synthetic method for indole-2-carboxylate and its application to the total synthesis of duocarmycin SA

The sequential coupling and cyclization reactions between aryl halides and methyl propiolate were investigated. The electron-withdrawing groups on the aromatic ring are essential for producing the methyl indole-2-carboxylate derivatives. On the other hand, the presence of an extra methyl propiolate and Pd(PPh3)4 were required to provide an efficient catalytic system for the cyclization reactions. This reaction was used for the total synthesis of duocarmycin SA.     

Decay time shortening of fluorescence from donor-acceptor pair proteins using ultrafast time-resolved fluorescence resonance energy transfer spectroscopy

We improved an ultrafast time-resolved fluorescence resonance energy transfer (FRET) spectroscopy system and measured directly the decrease in the fluorescence decay time of the FRET signal, without any entanglement of components in the picosecond time scale from the donor-acceptor protein pairs (such as cameleon protein for calcium ion indicator, and ligand-activated GRIN-Go proteins pair). The drastic decrease in lifetime of the donor protein fluorescence under the FRET condition (e.g. a 47.8% decrease for a GRIN-Go protein pair) proves the deformation dynamics between donor and acceptor fluorescent proteins in an activated state of a mixed donor-acceptor protein pair. This study is the first clear evidence of physical contact of the GRIN-Go proteins pair using time-resolved FRET system. G protein-coupled receptors (GPCRs) are the most important protein family for the recognition of many chemical substances at the cell surface. They are the targets of many drugs. Simultaneously, we were able to observe the time-resolved spectra of luminous proteins at the initial stage under the FRET condition, within 10 ns from excitation. This new FRET system allows us to trace the dynamics of the interaction between proteins at the ligand-induced activated state, molecular structure change and combination or dissociation. It will be a key technology for the development of protein chip technology.     

On Chow and Brauer groups of a product of Mumford curves

Let C₁,···,C_d be Mumford curves defined over a finite extension of and let X=C₁×···×C_d. We shall show the following: (1) The cycle map CH₀(X)/n → H^2d(X, μ_n^⊗d) is injective for any non-zero integer n. (2) The kernel of the canonical map CH₀(X)→Hom(Br(X),) (defined by the Brauer-Manin pairing) coincides with the maximal divisible subgroup in CH₀(X).     

New biologically active marine sesquiterpenoid and steroid from the okinawan sponge of the genus Axinyssa

A new bisabolane-type sesquiterpenoid, (E)-3-isocyanobisabolane-7,10-diene (1), and a new epidioxyergostane-type steroid, 9(11)-dehydroaxinysterol (2), were isolated from the Okinawan sponge of the genus Axinyssa. Their structures were elucidated based on the results of spectroscopic analysis and chemical conversion. Epidioxysterol 2 was found to show significant growth inhibitory effects against human cancer cell lines.     

A facile synthesis of novel types of cyclodextrin derivatives by insertion of an aromatic dicarbonyl spacer into a permethylated alpha-cyclodextrin skeleton

Novel types of cyclodextrin derivatives are easily synthesized by the insertion of an aromatic dicarbonyl spacer into the skeleton of permethylated alpha-cyclodextrin, and the isophthaloyl-inserted one shows almost the same complexing ability toward p-nitrophenol as permethylated beta-cyclodextrin.     

Growth of Na-doped Ca(2)CuO(2)Cl(2) single crystals under high pressures of several GPa

Single crystals of Na-doped Ca(2)CuO(2)Cl(2) have been grown for the first time by a flux method under high pressures of up to 5.5 GPa. By changing the Na-solubility limit through the applied pressure, the Na content x was successfully controlled without introducing appreciable compositional inhomogeneity within the millimeter-sized crystals. Structural and chemical characterization indicated that the crystals span the phase diagram continuously from the parent antiferromagnetic insulator to an underdoped high-temperature superconductor. Because of the well-defined cleavage plane and resulting high surface quality, these oxychloride single crystals will provide a unique opportunity to explore the electronic evolution of the high-temperature superconductors, using spectroscopic techniques such as scanning tunneling microscopy/spectroscopy and angle-resolved photoemission spectroscopy.     

Genetic-algorithm-based method to optimize spatial profile utilizing characteristics of electrostatic actuator deformable mirror

Arbitrary spatial beam shaping was demonstrated with a membrane electrostatic actuator type deformable mirror (DM). An automatic closed loop system must optimize such beam shapes as flattop. Well-characterized short pulse laser beam is widely required for a photocathode RF gun or for microscopic processing, etc. We propose a new sophisticated optimizing method based on a genetic algorithm (GA) for spatial shaping. A membrane type DM is driven by electrostatic attraction power, and applied electrode voltages vs displacement of membrane surface have a square function relationship. We prepare discrete electrode voltages to linearly change displacement as a utilized gene of the initial population in GA. Using uniform crossover without mutation in this method, we can make an arbitrary spatial beam shape quasi-flattop.     

Spectral interferometric optical coherence tomography with nonlinear beta-barium borate time gating

A high-speed, all optical coherence tomography system was designed and constructed. This tomography system employs spectral interferometry and optical Fourier transformation to reduce the number of mechanical scanning dimensions required for multidimensional profilometry. The system also employs a time gate comprising a beta -barium borate crystal driven by a femtosecond laser pulse to improve measurement time. This system has 43-mum depth resolution and 150-fs temporal resolution and is capable of taking 1000 cross-sectional image frames per second.