Spin polarization of β-emitting fragments in high energy heavy ions on Be collisions

The degrees of nuclear spin polarization of ^8,12B, ⁹C, ¹²N, ¹³O, ^20,21F, ²³Mg, ²⁷Si and ³⁹Ca produced in the high energy ^12,13C, ¹⁶O, ²²Ne, ²⁴Mg, ²⁸Si and ⁴⁰Ca ions on Be collisions have been measured systematically, for the technical developments of the nuclear moment studies as well as the hyperfine interaction studies by means of β-NMR technique. The fragment momentum dependences were well reproduced by the simple kinematical model. Incident energy dependence and the mass dependence as well as the reaction angle dependences were qualitatively explained by the mixing of the near and far side collisions. This revised version was published online in August 2006 with corrections to the Cover Date.     

Solid-State Structures and Photoluminescence of Lamellar Architectures of Cu(I) and Ag(I) Paddlewheel Clusters with Hydrogen-Bonded Polar Guests

Two hexanuclear paddlewheel-like clusters appending six carboxylic-acid pendants have been isolated with the inclusion of polar solvent guests: [Cu₆(Hmna)₆]·7DMF (1·7DMF) and [Ag₆(Hmna)₆]·8DMSO (2·8DMSO), where H₂mna = 2-mercaptonicotininc acid, DMF = N,N’-dimethylformamide, and DMSO = dimethyl sulfoxide. The solvated clusters, together with their fully desolvated forms 1 and 2, have been characterized by FTIR, UV–Vis diffuse reflectance spectroscopy, TG-DTA analysis, and DFT calculations. Crystal structures of two solvated clusters 1·7DMF and 2·8DMSO have been unambiguously determined by single-crystal X-ray diffraction analysis. Six carboxylic groups appended on the clusters trap solvent guests, DMF or DMSO, through H-bonds. As a result, alternately stacked lamellar architectures comprising of a paddlewheel cluster layer and H-bonded solvent layer are formed. Upon UV illumination (λ_ex = 365 nm), the solvated hexasilver(I) cluster 2·8DMSO gives intense greenish-yellow photoluminescence in the solid state (λ_PL = 545 nm, Φ_PL = 0.17 at 298 K), whereas the solvated hexacopper(I) cluster 1·7DMF displays PL in the near-IR region (λ_PL = 765 nm, Φ_PL = 0.38 at 298 K). Upon complete desolvation, a substantial bleach in the PL intensity (Φ_PL < 0.01) is observed. The desorption–sorption response was studied by the solid-state PL spectroscopy. Non-covalent interactions in the crystal including intermolecular H-bonds, CH⋯π interactions, and π⋯π stack were found to play decisive roles in the creation of the lamellar architectures, small-molecule trap-and-release behavior, and guest-induced luminescence enhancement.     

Contributions from the indirect ionic interactions to the elastic constants in the rock-salt structure crystals

Under the harmonic approximation, the contributions from the indirect ionic interactions to the elastic constants are calculated for the alkali halide and silver halide crystals with the rock-salt structure. The coupling constants of the indirect ionic interactions are calculated by the self-consistent field treatment of the local density approximation and the spherical solid model. The calculated values of the coupling constants are large for the silver ion. The indirect ionic interaction significantly affects the elastic constants. It quantitatively explains the deviation from the Cauchy relation in alkali halide crystals. Moreover, it provides a clear account for the large values of the deviation from the Cauchy relation in AgCl and AgBr.     

Retention Behavior of Nucleic Acid Bases and Purine Derivatives on Titania

The retention of nucleic acid bases and purine derivatives on titania was studied using a 0.4 mM acetic acid–sodium acetate buffer (pH 6.0) and 70% aqueous methanol as mobile phases. We observed that the retention strength of tested analytes on titania was dependent on the structural differences between pyrimidine and purine skeletons and the variety and number of substituents. The retention order was purine derivatives with methyl groups, pyrimidine bases and purine derivatives with hydrophilic functional groups, which were retained most strongly on titania. We concluded that the retention of each analyte was caused by the analyte’s hydrophobicity in the case of purine derivatives with methyl groups and pyrimidine bases. In the case of purine and its derivatives with hydrophilic functional groups, it was considered that the retention was dependent on the analyte’s ability to form chelates, and the variety and number of functional groups on C6 and C2.     

Oriented Monolayer Film of Gd2O3:0.05 Eu Crystallites: Quasi‐Topotactic Transformation of the Hydroxide Film and Drastic Enhancement of Photoluminescence Properties

Caught on film : A semitransparent and intensely luminescent monolayer film of oriented Gd₂O₃:0.05 Eu platelet crystallites is fabricated by annealing the precursor hydroxide film (see scheme). The photoluminescence properties of the as‐transformed film are greatly improved over those of the hydroxide film, and are much more pronounced than those of the corresponding Gd₂O₃:0.05 Eu powder.

     

Self‐Assembled Nanogel of Hydrophobized Dendritic Dextrin for Protein Delivery

Highly branched cyclic dextrin derivatives (CH‐CDex) that are partly substituted with cholesterol groups have been synthesized. The CH‐CDex forms monodisperse and stable nanogels with a hydrodynamic radii of ≈10 nm by the self‐assembly of 4–6 CH‐CDex macromolecules in water. The CH‐CDex nanogels spontaneously trap 10–16 molecules of fluorescein isothiocyanate‐labeled insulin (FITC‐Ins). The complex shows high colloidal stability: no dissociation of trapped insulin is observed after at least 1 month in phosphate buffer (0.1 M , pH 8.0). In the presence of bovine serum albumin (BSA, 50 mg · mL^?1), which is a model blood system, the FITC‐Ins trapped in the nanogels is continuously released (≈20% at 12 h) without burst release. The high‐density nanogel structure derived from the highly branched CDex significantly affects the stability of the nanogel–protein complex.

     

Tuning membership functions of kernel fuzzy classifiers by maximizing margins

We propose two methods for tuning membership functions of a kernel fuzzy classifier based on the idea of SVM (support vector machine) training. We assume that in a kernel fuzzy classifier a fuzzy rule is defined for each class in the feature space. In the first method, we tune the slopes of the membership functions at the same time so that the margin between classes is maximized under the constraints that the degree of membership to which a data sample belongs is the maximum among all the classes. This method is similar to a linear all-at-once SVM. We call this AAO tuning. In the second method, we tune the membership function of a class one at a time. Namely, for a class the slope of the associated membership function is tuned so that the margin between the class and the remaining classes is maximized under the constraints that the degrees of membership for the data belonging to the class are large and those for the remaining data are small. This method is similar to a linear one-against-all SVM. This is called OAA tuning. According to the computer experiment for fuzzy classifiers based on kernel discriminant analysis and those with ellipsoidal regions, usually both methods improve classification performance by tuning membership functions and classification performance by AAO tuning is slightly better than that by OAA tuning.     

Planar catechin analogues with alkyl side chains: a potent antioxidant and an alpha-glucosidase inhibitor

Planar catechin analogues having various alkyl side chain lengths were synthesized, and their remarkable antioxidative abilities and alpha-glucosidase inhibitory activities are shown.     

Ultra-slim laminated capillary array for high-speed DNA separation

We developed a new kind of capillary array for electrophoresis by using the numerical-control (NC) wiring technique conventionally used to produce printed-circuit boards. Laminating two polyimide sheets after laying cylindrical capillaries between them according to designed geometries, we fabricated a 16-lane laminated capillary array (LCA) 9.9 cm long, 7.2 cm wide, and 0.5 mm thick in which the effective length of all capillaries was only 10.9 cm. This compact LCA thus had separation columns as short as those in capillary array electrophoresis chips fabricated by lithography techniques. Like conventional capillary arrays, it also enabled pipetting-less direct injection of analytes from sample preparation plates. Using the LCA with LIF detection and a replaceable fluid sieving matrix, we demonstrated high-speed ssDNA fragment separations. At an electric field strength of 316 V/cm, 15 fragments ranging from 50 to 500 bases were completely separated within 5.8 min in all lanes. The lane-to-lane CV of migration time was only 0.38%, and the fragment size for which the resolution per base was 0.59 was 258 +/- 15 bases (average +/-SD).     

Long hydrogen-bonded rod of molecular oxide: a hexatantalate tetramer

A tetra-n-butylammonium (TBA) salt of [H(4.5)(Ta(6)O(19))](3.5-) was synthesized by reacting hydrous tantalum oxide with TBAOH. X-ray structural analysis of TBA(3.5)[H(4.5)(Ta(6)O(19))]·2THF·5.5H(2)O (THF = tetrahydrofuran) revealed that this compound consists of a hydrogen-bonded, rod-shaped tetramer of hexatantalate that is almost 30 ? long together with TBA cations and solvent molecules of crystallization [a = 20.6354(5) ?, b = 25.5951(7) ?, c = 37.2058(8) ?, α = 77.092(1)°, β = 86.177(1)°, γ = 88.683(1)°, V = 19110.9(8) ?(3), Z = 8, and space group P ?1]. (1)H NMR spectra showed that this tetrameric structure is maintained in solution.