Molecular Composition of Nonionic Vesicles Prepared from Span 80 or Span 85 by a Two‐Step Emulsification Method

The molecular compositions of the commercial nonionic surfactants Span 80 and Span 85 were analyzed by reversed phase high performance liquid chromatography (HPLC). Both surfactants are mixtures of fatty acid esters, containing monoesters, diesters, triesters, and tetraesters. While diesters dominate in the case of Span 80, Span 85 contains mainly tetraesters. Vesicles were prepared from Span 80 (or Span 85) by a two‐step emulsification method that involved homogenization and separation steps in which a portion of the surfactants was removed. The composition of the vesicles was analyzed by HPLC with respect to the different esters present. Although commercial Span 80 and Span 85 differ considerably in their molecular compositions, the ester profiles of the vesicles formed were in both cases rather similar and dominated by diesters. Therefore, the particular vesicle preparation method leads to a molecular selection of mainly those components that are prone to form bilayers.     

Photoinduced charge separation of phenothiazine–platinum–naphthalene diimide triads linked by twisted phenylene bridges

Two triads (i.e., 3PTZ–Pt–MNDI and 10PTZ–Pt–MNDI) consisting of 3-phenothiazine (3PTZ) or 10-phenothiazine (10PTZ), bipyridine–diacetylide platinum complex (Pt), and naphthalene diimide (MNDI) chromophores linked by highly twisted biphenylene spacers have been prepared. The formation and decay of the charge-separated (CS) states in toluene were studied by use of picosecond and nanosecond laser photolysis via selective excitation of the Pt moiety. The time required for formation of the CS state, PTZ⁺–Pt–MNDI^?, from PTZ–³Pt*–MNDI was determined to be τ _CS = 280 ps for 3PTZ⁺–Pt–MNDI^? and τ _CS = 230 ps for 10PTZ⁺–Pt–MNDI^?. The lifetimes of the CS states were determined to be τ _CR1 = 75 ns (95 %) and τ _CR2 = 285 ns (5 %) for 3PTZ⁺–Pt–MNDI^? and τ _CR = 830 ns for 10PTZ⁺–Pt–MNDI^?. Formation and decay of the CS states are discussed in terms the Marcus theory and the spin-correlated radical pair mechanism.     

Rapid method for the analysis of plutonium isotopes in a soil sample within 60 min.

A rapid method for the determination of Pu isotopes in a soil sample within 60 min of starting sample pretreatment was developed. The large reduction in the analysis time was attained by the rapid and perfect digestion of the sample using an alkaline fusion method with an induction heating machine. Pu concentrations were then determined by flow injection/ICP-MS using a solid extraction resin after preconcentration by batch extraction with a chelate resin. The limits of detection for 239Pu and 240Pu were 9.2 fg and 4.3 fg, corresponding to 0.03 and 0.05 Bq kg(-1), respectively, under our analytical conditions, which satisfy the lower detection limits (0.5 Bq kg(-1) of 239Pu, and 2 Bq kg(-1) of 240Pu) required for rapid analysis techniques by the Ministry of Education, Culture, Sports, Science and Technology, Japan. This method provides a powerful and practical technique for emergency monitoring in and around nuclear facilities that handle large amounts of plutonium.     

Three-dimensional numerical thrust performance analysis of hydrogen fuel mixture rotating detonation engine with aerospike nozzle

The propulsive performance for an H₂/O₂ and H₂/Air rotating detonation engine (RDE) with conic aerospike nozzle has been estimated using three-dimensional numerical simulation with detailed chemical reaction model. The present paper provides the evaluation of the specific impulse (I_sp), pressure gain and the thrust coefficient for different micro-nozzle stagnation pressures and for two configurations of conic aerospike nozzle, open and choked aerospike. The simulations show that regardless of the nozzle, increase the micro-nozzles stagnation pressure increases the mass flow rate, the pre-detonation gases pressure and consequently the post-detonation pressure. This gain of pressure in the combustion chamber leads to a higher pressure thrust through the nozzle, improving the I_sp. It was also found that the choked nozzle increases the chamber time-averaged static pressure by 50–60% compared with the open nozzle, inducing higher performance for the same reason explained before.     

Properties of Sr2FeMoO6 thin films fabricated by the chemical solution deposition method

We fabricated the ordered Sr₂FeMoO₆ (SFMO) thin film with a double perovskite structure using the chemical solution deposition (CSD) method. The highly c-axis oriented SFMO thin film with a high degree of Fe/Mo ordering was successfully synthesized on an MgO (001) substrate by optimizing processing conditions. The precise preparation process control of the SFMO precursor solution leads to a typical magnetoresistance effect in a low magnetic field at room temperature.     

Photoconduction of glasses in the TeSeSb system

The photoconductivity of bulk glasses of the TeSeSb system is measured as a function of light intensity and photon energy. The relative sensitivity (ΔI/I_d) has linear and square-root dependences on light intensity in low and high illumination intensities, respectively, and is nearly proportional to the square-root of the resistivity at room temperature. The spectral response of photoconductivity, which is calculated by taking into account the effect of surface recombination of carriers, agrees qualitatively with the experimental results. The experimentally determined broad spectral response suggests the presence of band tails below the conduction band and above the valence band. The large residual dark conductivity in the decay response is associated with the presence of many deep trapping centers.     

Synthesis and bioactivity of fluorescence- and biotin-labeled lipid A analogues for investigation of recognition mechanism in innate immunity

Fluorescence- and biotin-labeled lipid A analogues were synthesized for the investigation of bacterial lipopolysaccharide (LPS)/lipid A recognition in the innate immune system. For the introduction of the labeling moiety, a hydrophilic glutaryl-glucose linker was used for maintaining the bioactivity and also for preventing self-aggregation, which causes quenching of the fluorescence. We also observed the biological activity of the labeled compounds.     

Synthesis of immunoregulatory Helicobacter pylori lipopolysaccharide partial structures

The synthesis of immunoregulatory glycoconjugates, namely the active entity of lipopolysaccharide (LPS) from Helicobacter pylori was achieved. The results of biological activities of the LPS partial structures provide the structural basis for the immunobiological activity, especially for the immune inhibitory activity of H. pylori LPS.     

The line broadening and shift effects on the CO J=5-4 transition at 576 GHz induced by collisions with rare gases

The line profile of the CO J=5-4 transition at 576 GHz was measured precisely by a BWO-based submillimeter wave spectrometer. The foreign-gas effect on the broadening and shift of rare gases were determined together with the self-collision effects. The observed profiles exhibit clearly the Dicke narrowing effect for the cases of rare gas mixtures, and the Galatry function was used as the lineshape function in the analysis.