Bioconversion of a L-carnitin precursor in a one- or two-phase system

Applied Biochemistry and Biotechnology - The ability of the yeastSaccharomyces cerevisiae to bioconvert stereo-selectively octyl-4-chloroacetoacetate (OCA) into the corresponding chiral alcohol,...     

Measurement of the spin correlation parameter Aoonn and of the analyzing power for pp elastic scattering in the energy range from 0.5 to 0.8 GeV

The spin correlation parameter A_oonn and the analyzing powers A_oono and A_ooon were measured simultaneously, in the energy range 0.5–0.8 GeV and in the angular region 40°–80° CM. The experiment used the polarized proton beam of SATURNE II and the Saclay frozen spin polarized target.     

A liquid-phase peptide synthesis in cyclohexane-based biphasic thermomorphic systems

Combinations of typical organic solvents composed of cyclohexane and qualified aprotic polar organic solvents were found to realize an effective, biphasic thermomorphic system in arbitrary ratios of upper and lower phases that enable a practical application of a liquid-phase peptide synthesis.     

Formation process of indium oxide transparent conducting films via thermal decomposition

Indium 2-ethylhexanoate monohydroxide, In(OH)(O₂CCH(CH₂CH₃)(CH₂)₃CH₃)₂, is a precursory material to fabricate In₂O₃-based transparent conducting films by dip-coating process. Formation process of indium oxide transparent conducting films was investigated using an ultra-low acceleration voltage FE-SEM. The nanostructure change of the precursory layer was observed during the electron beam irradiation in vacuum. A flat and homogeneous surface of the as-coated layer changed to porous and net-work like nanostructure after 80 s; the pore diameter increased and the pore distance decreased although the number of pores remained unchanged. These processes were interpreted as the preliminary step to form porous films composed of nm-sized inter-linked oxide particles as reported in the previous papers by the authors.     

Fabrication of quartz microchips with optical slit and development of a linear imaging UV detector for microchip electrophoresis systems

We have developed quartz microchips for electrophoresis and a linear imaging UV detector along with the microchip. The microchips have an optical slit, which cut off the stray light in order to improve the sensitivity of UV absorption detection on the chip, at the bonding interface. They have been successfully fabricated on synthesized quartz glass substrates using the hydrofluoric acid (HF) solution bonding method. The signal level of UV absorption detection was effectively improved by applying microchips with the "on-chip" optical slit. It is also possible to improve the signal-to-noise ratio by repetitive scanning of linear photodiode array located along the separation channel, and signal averaging during elimination of the potential. Furthermore, the analysis may be performed until the separation of the target component is complete, because the real-time migration pattern of each component in the sample can be seen just as in a slab-gel electrophoresis, thus enabling a shorter analysis time.     

An analysis of VB structures in MO wave functions I

Summary A new method for the resolution of an antisymmetrized product of molecular orbitals into VB structures is proposed. Here VB structures are projected from a single Slater determinant associated with the ground state using the first-order density matrix. The present theory is applied to the ground state of some conjugated hydrocarbons, and special attention is paid to the covalent type VB structures.     

Photocatalytic reaction of neat alcohols by metal-loaded titanium(IV) oxide particles

The photocatalytic reaction (excitation wavelength, greater than 300 nm) of neat alcohols (ethanol or 2-propanol) by metal-loaded titanium(IV) oxide (TiO₂) was conducted under argon at room temperature. The dehydrogenation products hydrogen (H₂) and acetaldehyde (or acetone in the case of 2-propanol) were found in the absence of additives. The corresponding acetals, ethers, and alkanes were obtained by the addition of concentrated hydrochloric acid (HCl). The measurement of the product yields during the post-irradiation dark reaction in the presence of photocatalyst (TiO₂) loaded with platinum(IV) oxide (PtO₂) revealed that the production of ether and ethane and the regeneration of ethanol proceed by the hydrogenation of acetal over loaded metal, presumably via a hemiacetal intermediate. X-ray diffraction (XRD) analyses showed that the loaded PtO₂ is reduced to platinum metal during the course of the photocatalytic reaction. For the production of ether from HCl-acidified ethanol, Pd-loaded catalysts, especially prepared by precipitation—reduction, exhibit the highest activity of several metal-loaded TiO₂ catalysts. From XRD and X-ray photoelectron spectroscopy studies of Pd-loaded TiO₂ particles, it was shown that the smaller the size of the Pd particles, the higher the selectivity for ether production from the acidified ethanol suspension. The application of this photocatalytic O-alkylation to the synthesis of cyclic ethers was demonstrated.     

Preparation and properties of epoxy resins cured with silyl esters of phenol novolak and cresol novolak

The curing agents of epoxy resin, trimethylsilyl ethers of phenol novolak (TMSPN) and cresol novolak (TMSCN) were prepared by refluxing phenol novolak and cresol novolak respectively, with the mixture of hexamethyldisilazane and chlorotrimethylsilane in THF. The curing reaction of epoxy resin with these curing agents and the thermal properties of cured resins were examined. The Tg values of epoxy resins cured with TMSPN were a little higher than those cured with TMSCN. The maximum of Tg is 118°C for TMSPN-cured epoxy resin against 112°C for TMSPN-cured epoxy resin. The water absorption of hydrophobic epoxy resins cured with TMSPN was a little lower than those cured with TMSCN. The clear decrease of water absorption is attributed to the difficulty of the micro-void formation caused by the more tight primary structures of TMSPN. The water absorption at 25°C containing trimethylsilyl groups is about one-tenth of that of epoxy resins cured with conventional curing agents and even one-half of that of the epoxy resins cured with active esters. The low water absorption is attributed to the presence of trimethylsilyl groups, which are more hydrophobic than ester groups, and to the absence of hydroxyl groups of the cured resins. This revised version was published online in July 2006 with corrections to the Cover Date.