Solid-phase synthesis of liquid crystalline isoxazole library

Combinatorial library of isoxazoles was prepared by 1,3-dipolar cycloaddition on solid support. p-Cyano derivatives showed nematic and/or smectic A phases. A bilayer smectic phase for 2h is proposed by the combination of molecular mechanics calculation and X-ray diffraction experiment.     

Evaluation of a dual electrospray ionization/atmospheric pressure chemical ionization source at low flow rates (∼50 µL/min) for the analysis of both highly and weakly polar compounds

The atmospheric pressure ionization (API) source for a commercial mass spectrometer was modified to operate as a dual source in both the electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) techniques by simultaneously utilizing the electrospray probe and the corona discharge needle. A switching box was designed to operate in either manual or programmable modes to permit rapid switching between ionization techniques without changing sources, probes, or breaking vacuum. The source can be operated using the following ionization techniques: ESI only, APCI only, ESI/APCI simultaneously, and ESI/APCI alternatingly. The optimum operating conditions for these ionization techniques were similar to the manufacturer’s original specifications except that the APCI flow rate was lower (～50 µL/min versus 1000 µL/min) and externally heated nebulizing gas was found to be desirable. A four-component mixture, introduced by flow injection, was used to demonstrate the versatility of the dual ESI/APCI source.     

The solution photochemistry of αβ-unsaturated sulphones

1-Phenyl-2-(benzenesulphonyl)-ethylene and 1-phenyl-2-(benzenesulphonyl)-prop-1-ene have been shown to undergo $\text{Z}$,$\text{E}$-photoisomerisation, whereas 2-benzenesulphonylindene readily forms [_π2 + _π2] photoadducts with 2,3-dimethylbut-2-ene, cyclopentene, and cyclohexene.     

Density-fluctuation-induced swelling of polymer thin films in carbon dioxide

We report an anomalous swelling of polymer thin films in carbon dioxide (CO(2)) which is associated (in both locus and form) with the density fluctuation ridge that forms along the extension of the coexistence curve of gas and liquid in the P-T phase diagram. Neutron reflectivity results showed that CO(2) could be sorbed to a large extent ( approximately 60%) in thin polymer films even when the bulk miscibility of the polymer with CO(2) is very poor. The anomalous swelling is found to scale with the polymer radius of gyration (R(g)) and extends to a distance approximately 10 R(g).     

Unsupervised Image Segmentation Using Hierarchical Clustering

In the analysis of a medical image database aimed at formulating useful knowledge for image diagnosis requires an unsupervised image processing technique without preconceived knowledge. In this paper, we propose a method for unsupervised image segmentation, which is suitable for finding the features contained in an image. A small region around each pixel is considered as a pattern vector, and the set of pattern vectors acquired from the whole image is classified using the hierarchical clustering technique. In hierarchical clustering, the classification of pattern vectors is divided into two clusters at each node according to the statistical criterion based on the entropy in thermodynamics. Results of the test image generated by the Markov random field (MRF) model and real medical images photomicrographs of a colon tumor are shown.     

Magnetic behavior of Fe0.2Mg0.8TiO3 and Fe0.3Mg0.7TiO3 probed by Mössbauer timescale

Magnetization and Mössbauer measurements have been made on a diluted antiferromagnets Fe_xMg_1?xTiO₃ with x=0.2, 0.3 and 0.7. It has been demonstrated that this system exhibits a spin glass or a reentrant spin glass like behavior in the samples with x around the percolation concenrration x_c≈0.25. It has been shown that various sizes of magnetic clusters are formed well above the transition temperatures determined by the magnetization measurements in the samples with x near x_c. The behavior of Fe_0.2Mg_0.8TiO₃ is discussed as a typical cluster glass.     

Growth and properties of YAlO film synthesized by RF magnetron sputtering

YAlO films are synthesized on (1 0 0)-oriented Si substrates by RF magnetron sputtering method. Al₂O₃ wafer is used as a target material, and some small pieces of Y bulk material are put on the Al₂O₃ target to synthesize YAlO films. Y composition ratio is varied from 0 to 34%. Amorphous YAlO films are characterized. An electrical resistivity as high as 3.4 × 10¹⁴ Ω-cm is achieved for the YAlO film with Y composition ratio of 10%. The dielectric constant increases with increasing Y composition ratio, and the YAlO film with Y composition ratio of 34% has a dielectric constant of 10.2. The bandgap energy of the YAlO film is suggested to be wider than 6.5 eV. YAlO films with a surface roughness of 0.4-1.3 nm are obtained irrespective of the Y composition ratio.     

Interferometers for displacement-noise-free gravitational-wave detection

We propose a class of displacement- and laser-noise-free gravitational-wave-interferometer configurations, which does not sense nongeodesic mirror motion and laser noise, but provides a nonvanishing gravitational-wave signal. Our interferometers consist of four mirrors and two beam splitters, which form four Mach-Zehnder interferometers. By contrast to previous works, no composite mirrors with multiple reflective surfaces are required. Each mirror in our configuration is sensed redundantly, by at least two pairs of incident and reflected beams. Displacement- and laser-noise-free detection is achieved when output signals from these four interferometers are combined appropriately. Our 3-dimensional interferometer configuration has a low-frequency response proportional to f2, which is better than the f3 achievable by previous 2-dimensional configurations.     

The three-dimensional structure of aspergilloglutamic peptidase from Aspergillus niger

Aspergilloglutamic peptidase from Aspergillus niger is a novel pepstatin-insensitive acid endopeptidase distinct from the well-studied aspartic peptidases, and thus is an interesting target for protein structure/function studies. In the present study, we have determined the three-dimensional structure of the enzyme by X-ray crystallography to a 1.4-Å resolution. The results revealed that the enzyme has a unique structure, composed of two seven-stranded anti-parallel β-sheets which form a β-sandwich structure and appear to have a partial two-fold symmetry, suggesting its possible evolution by gene duplication and that the glutamic acid-110 and glutamine-24 in the heavy chain form a catalytic dyad, consistent with our results obtained by site-directed mutagenesis.