Molecular interactions between lipid bilayers and a water-soluble polymer

Molecular interactions between lipid bilayers (liposomes) and chondroitin sulfate C (CS), a water soluble polymer, have been investigated in terms of zeta-potential, particle size, microscopic-viscosity, microscopic-polarity of liposomes and permeability of calcein. Microscopic morphology is dramatically changed by the addition of CS to the positively charged liposomes (Pos.L), while it is not changed by the addition to uncharged liposomes (Unc.L) or negatively charged liposomes (Neg.L). The absolute value of the particle size of Pos.L increases with the addition of CS, while the zeta- potential of Pos.L decreases. Permeability of Pos.L decreases with an increase in the concentration of CS. Phase transition temperature of Pos.L is changed after the addition of CS. These values, however, are not changed for the other liposomes by the addition of CS. The results of gel filtration chromatography show that CS is absorbed on the Pos.L surface. Microscopic viscosity is also increased by the addition of CS to Pos.L due to the adsorption of CS.     

Diinsertion of fluorenylidene into a sulfur-sulfur bond of diaryl disulfides

Upon irradiation (>340 nm) of a benzene solution of diazofluorene with di-p-tolyl- or di-p-anisyl disulfide, the corresponding 9,9′-bis(arylmercapto)bifluorenyl was afforded in moderate to good yield accompanied by formation of 9,9′-bis(arylmercapto)fluorene. The major reaction pathway is considered to be a disulfur ylide formation followed by two times of successive Stevens rearrangement or by concerted electron redistribution via [2,3]sigmatropic rearrangement.     

Recent progress of high-power negative ion beam development for fusion plasma heating

A negative-ion-based neutral beam injector (N-NBI) has been constructed for JT-60U. The N-NBI is designed to inject 500 keV, 10 MW neutral beams using two ion sources, each producing a 500 keV, 22 A D⁻ ion beam. In the preliminary experiment using one ion source, a D⁻ ion beam of 13.5 A has been successfully accelerated with an energy of 400 keV (5.4 MW) for 0.12 s at an operating pressure of 0.22 Pa. This is the highest D⁻ beam current and power in the world. Co-extracted electron current was effectively suppressed to the ratio of Ie/I_D⁻ < 1. The highest energy beam of 460 keV, 2.4 A, 0.44 s has also been obtained. To realize 1 MeV class NBI system for ITER (International Thermonuclear Experimental Reactor), demonstration of ampere class negative ion beam acceleration up to 1 MeV is an important mile stone. To achieve the mile stone, a prototype accelerator and a 1 MV, 1 A test facility called MeV Test Facility (MTF) were constructed. Up to now, an H⁻ ion beam was accelerated up to the energy of 805 keV with an acceleration drain current of 150 mA for 1 s in a five stage electrostatic multi-aperture accelerator.     

Enantiomer separation of pharmaceuticals by capillary gas chromatography with novel chiral stationary phases

New chiral stationary phases of polydimethylsiloxane anchored with (S)-(-)-t-leucine derivatives were provided for use in enantiomer separation of pharmaceuticals by capillary gas chromatography. Fifteen pharmaceuticals were separated into their enantiomeric pairs by converting them into pentafluoropropionyl and heptafluorobutyryl derivatives. The separation factor and resolution obtained from the new phases were superior to those from the conventional Chirasil-Val capillary column.     

Marstomentosides O-T polyoxypregnane glycosides from Marsdenia tomentosa

Thirteen pregnane glycosides were isolated from fresh leaves of Marsdenia tomentosa collected in the Fukuyama district. Of these, six were glycosides previously obtained from the same plant collected in the Fukuoka district and one from another Asclepiadaceous plant. The structures of the six new glycosides were determined by spectrometric method.     

Ab initio calculations of isomerization reaction of diphosphene 1-sulfide to thiadiphosphirane

Ab initio Calculations of the isomerization reaction of diphosphene 1-sulfide (2′) to thiadiphosphirane (3′) suggest that the energy barrier of the reaction in the ground state is 25 kcal/mol and that 2′ lies 21 kcal/mol above 3′, while the calculations show that there exists one local minimum on the lowest triplet energy surface.     

Carbazoledioxazines having long alkyl groups. 2. Synthesis of carbazoledioxazines with angular type structure

Carbazoledioxazines with an angular type structure (5,15-dialkyl-7,17-dialkyloxy-9,19-dichloro-5,15-dihydrodiindolo[2,3-c:2′,3′-n]triphenodioxazines) were selectively synthesized by electrochemical oxidative ring closure of precursors (2,5-bis(9-alkyl-2-alkyloxy-3-carbazolylamino)-3,6-dichloro-1,4-benzoquinones). The structure was confirmed by ¹H-nmr and other instrumental analyses. Their thermal properties and solubilities were investigated and were compared with those of carbazoledioxazines with a linear type structure.     

Preparation and properties of SiO2-TiO2 thin films from silicic acid and titanium tetrachloride

The preparation of SiO₂-TiO₂ thin films by the sol-gel method using silicic acid and titanium tetrachloride as starting materials was studied. The homogeneous sols were obtained by the condensation reaction of silicic acid with titanium tetrachloride in methanol-tetrahydrofuran. The dipcoating of slide glasses and silicon wafers followed by heat treatment gave oxide thin films of 88–93% transmittance, 3000–4500 Å thickness, and 1.45–1.80 refractive index, depending on heat-treatment temperature and TiO₂ content. FT-IR measurement showed that the Si-O-Ti bond is formed even in the sol and films. The variations of film thickness and refractive index on transformation from the gels into the oxides were found to be quite low.     

The determination of sulfite in a flow injection system with chemiluminescence detection

The emission produced by sulfite on oxidation by permanganate in acidic solution in the presence of riboflavin phosphate or brilliant sulfaflavine is used to determine 0.9–35 ng of sulfite. Only sulfide and thiosulfate also give emissions.