Application of the 19F NMR technique to observe binding of the general anesthetic halothane to human serum albumin.

19F NMR techniques were employed to characterize the binding property of the widely used general anesthetic halothane with human serum albumin (HSA). It was found that 19F(1H) NOE and 2D 1H-19F HOESY experiments detected intermolecular NOEs between halothane 19F and HSA protons. Measurements of the diffusion coefficients for halothane were also carried out by 1H and 19F NMR, indicating the interaction of halothane with HSA. The present results indicate that these techniques are very suitable to identify a fluorine-containing ligand binding with a protein receptor in the drug-discovery process.     

Development of Non-Halogen Flame Retardant Optical Fiber and Optical Fiber Cord

A non-halogen highly flame-retardant 0.9mm optical fiber and 2.0mm simplex optical cord, which are harmonized with the ecosystem, have been developed. The characteristics of them are presented in this paper.     

Development and features of hydro-membrane gas chromatography.

Hydro-membrane gas chromatography (HMGC) is achieved by the annular condensation of water in a capillary column at less than 70 degrees C. The annular membrane of water is formed as a result of the wettability of the stationary phase, which is induced at a water contact angle ranging from 75 degrees to 79 degrees, as derived from a solubility parameter (delta) range of 15.7 +/- 0.3 MPa(1/2) of the coated resin. The range of the liquid to gas volume ratio (beta) required to support the annular membrane should be kept between 0.00005 and 0.0003. In the case of a 0.25-mm i.d. column, the ratio can be set by the combination of a 0.1 to 0.2 microl min(-1) water supply rate and helium gas flow rate. Separation by HMGC develops not only a gas-solid partition but also a focusing effect on the water membrane. One feature of HMGC is that it gives a non-adsorption chromatogram based on the blocking effect of pre-adsorbed water; furthermore, despite the presence of a relatively large quantity of water, the electron impact ionization efficiency is kept the same as in the usual GC/MS condition. The detection limit with the injection of 1 microl of aquatic solution was estimated to be less than 0.1 ppb of low-molecular-weight fatty acids with s/n = 5 on a mass chromatogram at m/z 45. The HMGC/EI-MS system can be applied to the trace analysis of C1 to C3 volatile acids, volatile inorganic acids, and halogenated organic acids in water.     

Numerical study on performance of disk MHD generator using frozen inert gas plasma

In an magnetohydrodynamic (MHD) generator using a frozen inert gas plasma (FIP), the availability of a frozen argon plasma, the influence of plasma uniformity at the generator inlet on the performance, and the feasibility of a large-scale generator are numerically examined by /spl gamma/-/spl theta/ two-dimensional simulation. The FIP is produced by pre-ionizing inert gas without an alkali metal seed at the generator inlet, then the ionization degree of the plasma is kept almost constant in the whole of the channel because of considerable slow recombination of the inert gas just like frozen reaction plasma. It is found that not only helium, but also argon frozen plasma MHD generation is realized, although highly accurate control of inlet ionization degree is necessary for argon. It is important to reduce the nonuniformity of plasma properties at the generator inlet in order to raise the maximum enthalpy extraction ratio. Even for the large-scale generator with 1000-MW thermal input, the ionization degree is kept almost constant in the whole of the channel and the high performance is obtainable. This result is extremely attractive for the FIP MHD generator.     

Mass spectrometric analysis of low molecular mass polyesters by laser desorption/ionization on porous silicon

A low molecular mass polyester was analyzed by desorption/ionization on porous silicon (DIOS) mass spectrometry. The results were compared with those of matrix-assisted laser desorption ionization (MALDI) mass spectrometry using matrixes of alpha-cyano-4-hydroxycinnamic acid (CHCA) and 10,15,20-tetrakis(pentafluorophenyl)porphyrin (F20TPP). The CHCA matrix was not suitable for characterization of low molecular mass components of the polyester because the matrix-related ions interfered with the component ions. On the other hand, the F20TPP matrix showed no interference because no matrix-related ions appeared below m/z 822. However, the solvent selection for determining optimal conditions of sample preparation was limited, because F20TPP does not dissolve readily in any of the available organic solvents. In the DIOS spectra, the polymer ions were observed at high sensitivity without a contaminating ion. No matrix is needed for DIOS spectra of low molecular mass polyesters, facilitating sample preparation and selectivity of a precursor ion in post-source decay measurements.     

The interface of the Ising model and the Brownian sheet

We study the limit theorem related to the interface of the three-dimensional Ising model. Dobrushin proved that the interface does not fluctuate and becomes rigid for sufficiently large. We define the random fieldX ^L (t, s), 0t, s1, on the interface, and prove that X^L(t, s) converges to the Brownian sheet as L for sufficiently large, whereL denotes the size of the system. This result does not mean that the interface itself converges to the Brownian sheet.     

Crystal structures of n-alkanes with branches of different size in the middle

We synthesized four branched n-alkane samples C35-C1, C35-C4, C35-C6, and C35-C4Ph with the same number of carbons as the main chain, n = 35, to which the methyl, butyl, hexyl, and butyl phenyl groups were respectively attached at the middle, and also the corresponding linear homologue of C35, and studied their crystalline structures from DSC, IR, and Raman spectroscopy, X-ray diffraction measurement, and computer simulation. Solid-solid phase transitions characteristic of linear alkane C35 are not observed for any branched alkanes, and their melting temperatures Tm are lowered to 325.2, 318.5, 314.3, and 314.1K, respectively. Main chains of branched alkane molecules are not folded, irrespective of length and chemical structure of branches, but are extended to take the planar zigzag form in the solid state. The branches of C35-C4 and C35-C6 are also aligned inside the crystal in the extended form. Data analyses on solution-grown crystallized samples reveal that, with increasing the branch length, their crystal structures transform from polymorphic forms of the orthorhombic (P2(1)2(1)2(1)) and the triclinic (P) for C35-C1 and C35-C4 to the unique triclinic form for C35-C6 and C35-C4Ph, so as to minimize extra surface energy invoked by introduction of long branches.     

Total synthesis of brevetoxin-B

Brevetoxin-B (BTX-B), produced by the red tide organism, Gymnodium breve Davis, is the first member of marine polycyclic ethers to be structurally elucidated and one of the most potent neurotoxins. The structural feature is a trans-fused polycyclic ether ring system with 23 stereocenters. Its unique, complex structure and potent biological activity have attracted the attention of synthetic organic chemists. Total synthesis of BTX-B has been accomplished via the coupling of the ABCDEFG and IJK-ring segments, each ether ring of which was stereoselectively and efficiently constructed on the basis of SmI2-induced intramolecular cyclization, 6-endo-cyclization of hydroxy epoxide, ring-closing olefin metathesis, and SmI2-induced intramolecular Reformatsky-type reaction. Several kinds of double reactions at the left and right sides were efficiently used through the synthesis.     

Synthesis of large macrocyclic tetraaza compounds with a methylene backbone: Cyclo[-NH- (CH2)n-]4, (n = 6, 7, 8, 9 and 10). The formation of 28-, 32-, 36-, 40- and 44-membered rings

A series of macrocyclic tetraamines with 28-, 32-, 36-, 40- and 44-membered rings have been efficiently prepared from the corresponding ditosylamide and monobromoalcohol derivatives in 6 steps via a double condensation reaction. Overall yields were: 41, 41, 46, 29, and 33%, respectively, for 1,8,15,22-tetraazacyclooctacontane ( 11a ), 1,9,17,25-tetraazacyclodotriacontane ( 11b ), 1,10,19,28-tetraazacyclohexatriacontane ( 11c ), 1,11,21,31-tetraazacyclotetracontane ( 11d ) and 1,12,23,34-tetraazacyclotetratetracontane ( 11e ).