Changes in the near-edge X-ray absorption fine structure spectra of long-chain diacetylene derivatives through photopolymerization in Langmuir–Blodgett films

Photopolymerization of cadmium 10,12-pentacosadiynoate (CdDA) in Langmuir–Blodgett (LB) films, with the molecular packing well arranged by moderate preannealing, was investigated with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Greenish films of polydiacetylene with an absorption wavelength of 705 nm were obtained through the photopolymerization of preannealed monomer LB films, and this resulted in an extended π-conjugate system based on the well-ordered monomer in a two-dimensional arrangement. The electronic structures of the polydiacetylenes were found to be correlated to the variation of the molecular arrangements in the films from the changes in the NEXAFS spectra through photopolymerization in the LB films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2329–2336, 2004     

On singularities arising from the contraction op the minimal section of a ruled surface

We will discuss the Gorenstein property of the singularity which is blown down from the minimal section of a ruled surface in terms of the extension class. In the case that the base field has positive characteristic, we find a new example (3.4) of Gorenstein singularity in connection with Theorem B.     

Magnetism in electron-doped copper oxides

We report muon spin relaxation/rotation measurements on sintered powder samples of Nd_2−x Ce _x CuO_4−y and a large single crystal of Nd₂CuO_4−y . We find an electronic phase diagram which is quite similar to that of hole-doped superconductors such as La_2−x Sr _x CuO_4−y , although the doping of electrons into the system is less efficient in destroying the static moments on the copper spins. Static magnetic order in Nd₂CuO_4−y appears below about 250 K, and two spin reorientations are seen atT=75 K andT=35 K. Measurements of the magnetic field penetration depth have been unsuccessful due to the rare-earth paramagnetism of these materials.     

Mesure invariante pour l’équation stochastique d’un modéle de compétition limitée entre des espéces avec une diffusion spatiale

On considére l’équation stochastique decrivant un systéme den espéces avec une perturbation stochastique du type environnemental et une diffusion dans un territoire de chaque espéce. On suppose la compétition avec un effet limité entre le espéces différentes, tandis que l’effet logistique pour chaque espéce est supposé quadratique. Sous une condition convenable pour les coefficients, on démontre l’existence d’une mesure invariante pour cette équation stochastique, oú la densité de population de chaque espéce est presque surement positive.      

Plane curves whose singular points are cusps and triple coverings of ℙ2

We study a plane curve C whose singular points are cusps and the surface which is a triple covering of ² branched along C. As a result, especially we obtain an inequality for the sum of the Milnor numbers at the singularities of C and new surfaces of general type.     

Improvement of Dispersion and Release Properties of Nifedipine in Suppositories by Complexation with 2-Hydroxypropyl-β-cyclodextrin

Geometries, electronic properties and NMR-shielding of cucurbit[5]uril, decamethylcucurbit[5]uril, cucurbit[6]uril, cucurbit[7]uril, and cucurbit[8]uril are investigated with DFT calculations. All molecules are highly symmetrical with a distinct geometric flexibility. In addition with a characteristic partial charge distribution these findings account for their chemical complex building ability.     

Ru(II)-catalyzed chemo- and regioselective cyclotrimerization of three unsymmetrical alkynes through boron temporary tether. One-pot four-component coupling via cyclotrimerization/Suzuki-Miyaura coupling

The Ru(II)-catalyzed [2+2+2] cyclotrimerization of alkynylboronates, propargyl alcohol, and terminal alkynes proceeded chemo- and regioselectively to give rise to arylboronates, which were subjected to Suzuki-Miyaura cross-coupling with aryliodides to afford highly substituted biaryls in 53-76% yields.     

Measurement of attachment force of microbial cells

A parallel-plate flow chamber consisting of two transparent electro-conductive glass plates was constructed. The two glass plates were set parallel to each other and connected to a potentiostat apparatus to regulate the strength of the electric field between the plates. A microbial cell suspension was flowed through the chamber. This system enabled the application of an electrostatic force to suspend charged particles, e.g. microbial cells, existing between the two plates. The time course of the cell attachment of Pseudomonas syringae pv. atropurpurea NIAES 1309 suspended in 10 mM phosphate buffer solution (pH 7.0) to the glass plate was investigated at various electric field strengths ranging from −4.2 to +4.1 V cm⁻¹. The attachment rate and the maximum number of attached cells increased linearly with the increase in the strength of the positive electric field. In contrast, the rate and the number of cells decreased linearly with the decrease in the strength of the negative electric field. These linear relations gave a specific value for the strength of the electric field (−5.9 ± 0.7 V cm⁻¹) where the electrostatic repulsion and the microbial attachment force were thought to be equal, resulting in no cell attachment. From this value, the electrostatic repulsion, i.e. the microbial attachment force, was calculated to be 5.0 × 10⁻¹¹ N cell⁻¹ for cells of average size.     

Ligand Substitution Reaction of Bis(ethylenediamine)glycinatocobalt(III) Complex with Ethylenediamine Catalyzed by the Photo-excited Tris(2,2′-bipyridine)ruthenium(II) Complex

Substitution reaction with ethylenediamine of coordinated glycinate ligand in bis(ethylenediamine)-glycinatocobalt(III) complex has been studied in the presence of photo-excited tris(2,2′-bipyridine)ruthenium(II) complex in alkaline aqueous solution (buffered around pH 12) containing 1.0M chloride ion at 25°C. VIS absorption and CD spectra were used for the racemate and the optically active isomers of the Co(III) complexes, respectively. The reaction was catalyzed by the excited Ru(II) complex to give tris(ethylenediamine)cobalt(III) complex. Mechanism of the ligand-substitution reaction and role of the excited Ru(II) complex were discussed.