Monte carlo simulations for blue-phase structure in liquid crystals

Blue-phase liquid crystals form three-dimensional structures in a self-organizing manner and are similar to living tissue structures such as the teeth of mice and collagen tissues. This study presents numerical results regarding the conditions under which blue-phase liquid crystals occur. The Monte Carlo simulations are performed by employing an improved Lennard–Jones potential that considers anisotropy and chirality. The conditions for the formation of the blue phase, which vary with respect to the chirality, are examined first. The relationship between the anisotropic parameters and the chiral parameter for the formation of the blue phase is discussed. Identical blue-phase structures are obtained, even when the cell size and molecular number are varied drastically. This discussion is useful for considering the scale-up problem, which is almost always a difficult issue for molecular-scale simulations.     

Stereoselective one-pot preparation of 1,2,4,5-tetraalkylidene- and 1,4-dialkylidenecyclohexanes

1,2,4,5-Tetraalkylidene- and 1,4-dialkylidenecyclohexanes were prepared by the regio- and stereoselective homocoupling of skip-type diynes and enynes, and their Diels-Alder reaction to form a polycyclic compound was demonstrated.     

Holographic reconstruction with a 10- mum pixel-pitch reflective liquid-crystal display by use of a light-emitting diode reference light

We reconstructed an animation made from computer-generated holograms with a reflective LCD panel that had a pixel pitch of 10 mumx10 mum and resolution of 1400x1050 . Using a LED as the reference light, we could clearly observe three-dimensional images whose size was approximately 30 mmx10 mm x30 mm . Moreover, we reconstructed a color holograph by use of a simple system with a set of red, green, and blue LEDs as the reference light.     

Structure and synthesis of a new hypotensive vasodilator isolated from Streptomyces aureofaciens

The structure elucidation and synthesis of WS-1228 A, produced by $\text{Streptomyces aureofaciens}$, were described.     

Selective oxidation of hydroxy groups of phenylthio and phenylseleno alcohols

Various kinds of alcohols bearing phenylthio or phenylseleno moiety were converted into the corresponding carbonyl compounds in good to excellent yields by treating with dimesityl diselenide and $\text{tert}$-butyl hydroperoxide.     

Production of doubly charged helium ions by two-photon absorption of an intense sub-10-fs soft x-ray pulse at 42 eV photon energy

We report on the observation of doubly charged helium ions produced by a nonlinear interaction between a helium atom and photons with a photon energy of 42 eV which are generated with the 27th harmonic of a femtosecond pulse from a Ti:sapphire laser. The number of ions is proportional to the square of the intensity of the 27th harmonic pulse, and thus two-photon double ionization should be dominantly induced as compared with other nonlinear processes accompanying sequential ionization via a singly charged ion. This phenomenon is utilized to measure the pulse duration of the 27th harmonic pulse by using an autocorrelation technique, for the first time to our knowledge, and as a result a duration of 8 fs is found.     

Chaotic itinerancy in the oscillator neural network without Lyapunov functions

Chaotic itinerancy (CI), which is defined as an incessant spontaneous switching phenomenon among attractor ruins in deterministic dynamical systems without Lyapunov functions, is numerically studied in the case of an oscillator neural network model. The model is the pseudoinverse-matrix version of the previous model [S. Uchiyama and H. Fujisaka, Phys. Rev. E 65, 061912 (2002)] that was studied theoretically with the aid of statistical neurodynamics. It is found that CI in neural nets can be understood as the intermittent dynamics of weakly destabilized chaotic retrieval solutions.     

Tumor-infiltrating effector cells of alpha-galactosylceramide-induced antitumor immunity in metastatic liver tumor

BACKGROUND: alpha-Galactosylceramide (alpha-GalCer) can be presented by CD1d molecules of antigen-presenting cells, and is known to induce a potent NKT cell-dependent cytotoxic response against tumor cells. However, the main effector cells in alpha-GalCer-induced antitumor immunity are still controversial. METHODS: In order to elucidate the cell phenotype that plays the most important role in alpha-GalCer-induced antitumor immunity, we purified and analyzed tumor-infiltrating leukocytes (TILs) from liver metastatic nodules of a colon cancer cell line (Colon26), comparing alpha-GalCer- and control vehicle-treated mice. Flow cytometry was performed to analyze cell phenotype in TILs and IFN-gamma ELISA was performed to detect antigen-specific immune response. RESULTS: Flow cytometry analysis showed a significantly higher infiltration of NK cells (DX5+, T cell receptor alphabeta (TCR)-) into tumors in alpha-GalCer-treated mice compared to vehicle-treated mice. The DX5+TCR+ cell population was not significantly different between these two groups, indicating that these cells were not the main effector cells. Interestingly, the CD8+ T cell population was increased in TILs of alpha-GalCer-treated mice, and the activation level of these cells based on CD69 expression was higher than that in vehicle-treated mice. Moreover, the number of tumor-infiltrating dendritic cells (DCs) was increased in alpha-GalCer-treated mice. IFN-gamma ELISA showed stronger antigen-specific response in TILs from alpha-GalCer-treated mice compared to those from vehicle-treated mice, although the difference between these two groups was not significant. CONCLUSIONS: In alpha-GalCer-induced antitumor immunity, NK cells seem to be some of the main effector cells and both CD8+ T cells and DCs, which are related to acquired immunity, might also play important roles in this antitumor immune response. These results suggest that alpha-GalCer has a multifunctional role in modulation of the immune response.     

Comparison in fractal dimension between those obtained from structure factor and viscoelasticity of gel networks of 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol in polystyrene melt at gel point

We investigated time evolution of shear moduli in the physical gelation process of 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol in polystyrene melt. At the gel point, storage and loss shear moduli, G' and G", were described by the power law of frequency omega, G' approximately G" approximately omegan, with the critical exponent n being nearly equal to 2/3, in agreement with the value predicted by the percolation theory. We also investigated the structure factor over two decades in length scale at gel point by using ultra-small-angle X-ray scattering, and small-angle X-ray scattering. We found the power-law behavior in low-q region, indicating that the gel network forms the self-similar structure with mass-fractal dimension. Comparison between the exponent of mass-fractal dimension from structure factor and that from viscoelasticity indicates that hydrodynamic interactions are completely screened out and the excluded volume effects are dominant in the gel. The gel strength was found to increase with the decrease in the lower limit length scale of fractality.