Determination method for steroid 5alpha-reductase activity using liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry.

A determination method for steroid 5alpha-reductase activity using liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC/APCI-MS) in the positive-ion mode has been developed. The rat prostatic enzyme source was used and the enzymatically formed 5alpha-dihydrotestosterone and 5a-androstane-3alpha,17beta-diol were determined by LC/APCI-MS using absolute calibration curve method. The sum of the formed products was used as a measurement of the enzyme activity. This method was applied to kinetic study of this enzyme and inhibitory experiments using Finasteride as a model inhibitor.     

Ni-catalyzed addition reaction of allylic selenides to alkynes

Nickel complex catalysts, Ni(cod)₂-2PPh₃ and Ni(cod)₂-dppb systems in particular, catalyze the addition reactions of phenyl allyl selenide to terminal alkynes to regioselectively afford 2-phenylseleno-1-allyl-1-alkenes in good to excellent yields. A mechanism that involves a η³-allyl-nickel complex is proposed on the basis of isolation, crystal structure determination and reactivity study of the complex.     

Synthesis of 4‐styrylphthalhydrazides and their chemiluminescence reaction. Emitters and chemiluminescence efficiency highly dependent on electronic nature of styryl goups

A series of 4‐styrylphthalhydrazides were synthesized and their chemiluminescence reactions were investigated. The chemiluminescence quantum yields as well as the emitters were variable depending on the electronic nature of the terminal substituents attached on the styryl groups. It was revealed that the excited phtha‐late ions were the emitters when they were highly fluorescent, while the energy transfer chemiluminescence from the excited phthalate ions to the phthalhydrazide anions took place when the fluorescence of the corresponding phthalate ions were very weakly fluorescent.     

Synthetic studies of fluorine-containing compounds for household insecticides

The discovery stories of three fluorine-containing insecticides in our laboratory are described, i.e. amidoflumet, a new trifluoromethanesulfonanilide with high miticidal activity against various house dust mites, Metofluthrin, a potent new fluorinated pyrethroid with extremely high knockdown activity against various mosquitoes, and a new α-pyrone compound, 3-[1R-trans-(2-trifluoromethyl)cyclopropanecarbonyl]-4-hydroxy-6-methyl-2-pyrone with outstanding insecticidal activity against Blattella germanica.     

Synthesis and lyotropic liquid crystal properties of chiral helical polycarbodiimides

Chiral helical polymers have been expected to exhibit optical activity with a significantly large optical rotation power. In this paper polymethylphenylethylcarbodiimides (Poly-PhEMCDI) with helical structure were synthesized by the insertion polymerization of a corresponding chiral monomeric carbodiimide initiated by a copper complex. The circular dichroism spectra and optical rotation power induced by the ordered rigid main chain helical structure of polycarbodiimides, in solution and as cast films, were studied. Polycarbodiimides have a rigid rod helical structure and form lyotropic liquid crystal (LLC) in organic solvents such as dichloromethane (DCM), chloroform and THF. The LLC phase was studied using polarizing optical microscopy and X-ray diffraction. A chiral nematic phase was formed in DCM and chloroform in the concentration range 20-36%. Spherulites were formed in more concentrated solution. The formation of a LLC phase in polycarbodiimides organic solutions makes it possible to align the polymer helical chain to form an ordered film for electro-optical applications.     

Autonomic healing of a pinhole in polyethylene and photografted polyethylene‐g‐poly(hexyl methacrylate) films

The structural changes of polyethylene (PE) and photografted polyethylene‐g‐poly(hexyl methacrylate) (PE‐g‐PHMA) with the mechanical formation of pinholes were evaluated with differential scanning calorimetry, wide‐angle X‐ray scanning, and small‐angle X‐ray scanning. The crystallinity and the long period of the lamella increased with pricking under extremely high compression stress. The partial transformation of an orthorhombic crystal into a monoclinic one was also detected. The autonomic healing of pinholes in PE and PE‐g‐PHMA was studied in detail. The degree of healing increased with an increase in the grafting ratio of poly(hexyl methacrylate) (PHMA). Three mechanisms for the healing were investigated and related to the molecular motions of PE and PHMA grafted chains, which were evaluated with dynamic mechanical analyses. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1705–1714, 2004     

Photoelastic investigation of large deflections by low-modulus photoelastic materials

Information is given to enable the experimental analysis of large deformations by application of photoelastic techniques. Promising photoelastic materials having low elastic modulus and high optical sensitivity were obtained for practical use at room temperature. The time and temperature dependence of the stress-fringe order and stress-strain relations of one of these viscoelastic materials is discussed. Photoelastic investigations of large deflected straight and circular beams are reported. Photoelastic technique seems to be a useful method for analysis of large deformations of models with complicated shapes.