Carbon dioxide as a porogen on self-organized nano-structure of amphiphilic side-chain type liquid crystalline di-block copolymers

Liquid and supercritical carbon dioxide (LCO₂, SCCO₂) have been used as a porogen to swell self-organized nano-structure of an amphiphilic side-chain type liquid crystalline PEO–b-PMA(Az) copolymer. Carbon dioxide interacts with the hydrophilic PEO domain rather than the PMA matrix. The preferential interactions of PEO component with carbon dioxide result in a solvent-induced surface topology changes and the generation of a nano-porous template. The area density of the nano-pores is identical to that of the original copolymer film while keeping the hexagonally packed PEO nano-scale organization. Since the process is based on the gases diffusion on solid surfaces under controlled temperature and since neither polymer block is fundamentally altered by the sorption effect, the process is fully reversible. The supercritical condition of CO₂ treatment gives rise to the highest expansion of pre-patterned PEO cylinders and consecutively induces the retardation of PEO crystallization. This versatile thermo-diffuso approach would be applied to a wide variety of pre-patterned copolymers systems for nano-templating applications requiring nano-scale features sizes and/or area feature densities.     

Alternative synthetic path to (−)-adalinine via a SmI2-promoted fragmentation of a 3-oxopyrrolidine derivative

A novel and stereocontrolled synthetic path to a coccinellid alkaloid, (−)-adalinine, was established by employing the reductive carbon-nitrogen bond cleavage reaction and subsequent recyclization of a 3-oxopyrrolidine derivative with samarium diiodide, as key steps, where water was found to be the best proton source.     

Hydrogen-bonded liquid crystals built from hydrogen-bonding donors and acceptors. Infrared study on the stability of the hydrogen bond between carboxylic acid and pyridyl moieties

The stability of a hydrogen-bonded complex built through inter-molecular hydrogen bonding between carboxylic acid and pyridine fragments has been examined using infrared spectroscopy. Infrared spectra as a function of temperature have been recorded for the 1:1 complex of 4-hexyloxybenzoic acid and trans-4-propoxy-4'-stilbazole from the crystalline state to the isotropic state. A dependence of the stability of the hydrogen bond on molecular orientation is observed clearly in the infrared spectra. The spectra also suggest that the hydrogen bond is an unionized type with a double minimum potential energy.     

Measurement of the polarization for the reactions K+n → K+n and K0p at 1.06, 1.28, 1.39 and 1.49 GeV/c

The polarization for the K⁺n elastic and charge-exchange reactions was measured at the momenta of 1.06, 1.28, 1.39 and 1.49 GeV/c. It was found to be negative for the K⁺n elastic process and generally positive for the charge-exchange process. The present results are compared with the predictions of phase shift analyses.     

Cholesterol location and orientation in aqueous suspension of large unilamellar vesicles of phospholipid revealed by intermolecular nuclear overhauser effect

The locational and orientational structure and the dynamics of cholesterol in the bilayer membrane were studied by using the solution-state NMR. The intermolecular nuclear Overhauser effect (NOE) was analyzed for large unilamellar vesicles (100 nm in diameter) composed of dimyristoylphosphatidylcholine (DMPC) and cholesterol at cholesterol concentrations of 9-33 mol %. The DMPC headgroups show (1)H-{(1)H}-NOEs with the methyl groups at the hydrophobic terminals of both cholesterol and DMPC, illustrating the significant fluctuation of the bilayer membrane in the vertical (bilayer normal) direction. Cholesterol was found to keep the hydroxyl (OH) group toward the outer water pool on the basis of the following observations: (1) the cross correlation between the DMPC headgroup and the cholesterol terminal methyl group is weaker than those between the DMPC headgroups and (2) the methyl group at the hydrophobic terminal of cholesterol shows strong correlation with the terminal group of the DMPC chain portion. The OH group plays a crucial role in orienting cholesterol with its OH group outward, since cholestane, which has a molecular structure similar to that of cholesterol except for the absence of the OH group, was found to have no orientational preference in the bilayer membrane. The dynamic slowdown at high cholesterol concentrations is demonstrated on the basis of the correlation times for NOE as well as the broadening of the proton linewidths.     

Total synthesis of (+)- and (-)-sundiversifolide via intramolecular acylation and determination of the absolute configuration

Intramolecular acylation of an organolithium leads to an efficient stereocontrolled total synthesis of both enantiomers of sundiversifolide. The absolute configuration was determined by HPLC analysis and allelopathy assay. The gamma-lactone moiety resulted from a butenolide was obtained by the condensation of a bicyclic alpha-hydroxyhemiacetal with Ph3P=CMe(CO2R).     

Improvement in appearance of colors for elderly persons using lightness transform

The color of an object appears to be different for elderly and young persons. This is because human visual features vary with on age. In general, the spectral transmittance of the crystalline lens of an elderly person is lower than that of a young person. The low spectral transmittance decreases the brightness of the visual field. This phenomenon affects the color appearance of an image in human visual perception. In this paper, a lightness transform method is proposed to improve the color appearance of images for elderly persons. In the proposed method, colors that are difficult for an elderly person to see are transformed into colors that are easy to see by adding lightness contrast. The performance of the proposed method is confirmed in experiments using digital images.