PHOTOCHEMISTRY OF ACETYLENIC KETONES IN MICELLAR SOLUTIONS AS STUDIED BY PRODUCT-YIELD-DETECTED ESR AND TRANSIENT ABSORPTION TECHNIQUES

The electron spin resonance (ESR) spectra of the transient radical pairs in the photoreduction of 1,5-diphenyl-1,4-pentadiyn-3-one ( I ) and 1,3-diphenyl-2-propyn-1-one ( II ) in sodium dodecyl sulfate (SDS) micellar solutions have been obtained by using the product-yield-detected ESR (PYESR) technique. The PYESR spectra, detected by tracing the microwave effect on the spin-adduct yield as functions of the magnetic field, show the ESR spectra of the ketyl radical of the ketone and SDS radical as the components of the radical pairs. In addition, the growth and the decay processes of the radical pair were observed through detecting the effect of microwave pulse as functions of the delay period between a laser pulse and the off and on time, respectively, of a microwave pulse. The absorption spectra of transient species have also been obtained by using the laser flash photolysis technique. Through the analysis of these data and molecular orbital calculations, the role of acetylenic groups in the photoreactivity of acetylenic ketones is discussed.     

Correlators of matrix models on homogeneous spaces

We investigate the correlators of TrA_μA_ν in matrix models on homogeneous spaces: S² and S²×S². Their expectation value is a good order parameter to measure the geometry of the space on which non-commutative gauge theory is realized. They also serve as the Wilson lines which carry the minimum momentum. We develop an efficient procedure to calculate them through 1PI diagrams. We determine the large N scaling behavior of the correlators. The order parameter shows that fuzzy S²×S² acquires a 4-dimensional fractal structure in contrast to fuzzy S². We also find that the two point functions exhibit logarithmic scaling violations.     

Entropy-controlled supramolecular photochirogenesis: enantiodifferentiating Z-E photoisomerization of cyclooctene included and sensitized by permethylated 6-O-benzoyl-beta-cyclodextrin

In contrast to the photosensitization with a non-methylated analogue, supramolecular photochirogenesis with a novel permethylated mono(6-O-benzoyl)-beta-cyclodextrin exhibited a critical dependence of the product's enantiomeric excess upon temperature, and possessed a large differential entropy of activation (-11 J K(-1) mol(-1)) for which the flexible host skeleton is likely to be responsible.     

Depth visualization of a local blood region in skin tissue by use of diffuse reflectance images

A simple method is proposed for visualizing the depth distribution of a local blood region in skin tissue by using diffuse reflectance images at two isosbestic wavelengths of hemoglobin, 420 and 585 nm. Monte Carlo simulation of light transport specifies a relation between optical densities and the depth of the region under given concentrations of melanin in the epidermis and blood in the dermis. Phantom and in vivo experiments were performed to show the usefulness of the method.     

Biyouyanagin A, an anti-HIV agent from Hypericum chinense L. var. salicifolium

[structure: see text] A structurally unique hydrophobic compound, biyouyanagin A, was isolated from the MeOH extract of the leaves of Hypericum chinense L. var. salicifolium. The structure of biyouyanagin A was elucidated on the basis of spectroscopic evidence. Biyouyanagin A showed a significant activity against HIV and inhibited cytokine production.     

Stereoselective photooxidation of enecarbamates: reactivity of ozone vs singlet oxygen

[reaction: see text]. Oxazolidinone-functionalized enecarbamates show contrasting behavior upon oxidation by singlet oxygen and by ozone. The observed stereoselectivity difference indicates that the oxidation with ozone is subject to classic steric effects, whereas the very high selectivity in the photooxidation with singlet oxygen is derived from vibrational deactivation.     

Ligularidine,a new pyrrolizidine alkaloid from Ligularia dentata

The structure of a new macrocyclic pyrrolizidine alkaloid, ligularidine(1), having significantly high mutagenic activity was elucidated and the configurations of the necic acid and its enantiomer reported by Edwards² were also determined.     

Progress of coherent optical fibre communication systems

The recent progress of coherent optical fibre communication systems is reviewed. System constituent technologies, such as coherent optical modulation-demodulation, optical direct amplification for repeaters and single polarization fibre transmission are outlined. Several important optical device technologies, such as frequency stabilization of semiconductor lasers, AM and FM quantum noise and their reduction, and integrated opto-electronic devices, are also described. Finally, on the basis of the current state of the art in these technological areas, the expected system performance and future problems are discussed.     

Estimation of Absorbing Components in a Local Layer Embedded in the Turbid Media on the Basis of Visible to Near- Infrared (VIS-NIR) Reflectance Spectra

A new method is studied for estimating the hemoglobin concentration and oxygenation of a local blood layer in a human skin tissue model on the basis of visible and near infrared reflectance spectra. This method uses the iterative Monte Carlo technique for a multi-layered skin tissue model. The numerical simulation was performed to investigate the effects of estimation errors for epidermis and dermis layers on the results for the local blood layer. Experiments with skin tissue phantoms were performed to verify the possibility of this method.