Cell separation in microcanal coated with electrically charged phospholipid polymers

To separate the cell population in whole blood using microcanal, the surface was covered with a polyion complex (PIC) composed of electrically charged phospholipid polymers. The phospholipids polymers were prepared by the polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and n-butyl methacrylate with 3-(methacryloyloxypropyl)-trimethyl ammonium iodide as the cationic unit or potassium 3-methacryloyloxypropyl sulfonate as the anionic unit. The PIC was formed at the solid-liquid interface, that is, first, the cationic polymer was coated on the substrate and an aqueous solution containing the anionic polymer with different concentrations was applied to the polymer-coated substrate. The formation of the PIC was followed using a quartz crystal microbalance (QCM), and the PIC surfaces were analyzed by both zeta-potential measurement and X-ray photoelectron spectroscopic measurement. The surface electrical potential on the PIC was controllable from +40 to -40 mV by increasing the amount of the adsorbed anionic polymer. The PIC surface was prepared in microcanal. The surface electrical potential was sequentially changed. When the whole blood was introduced into the microcanal, the cells adhered on the positively charged surface, but could not adhere to the negatively charged surface. Even when the cells adhere to the surface, the morphology of cells was maintained. This is due to MPC units at the surface, which show a good biocompatibility. These results indicated that the change in the surface electrical potential will be a useful method to separate the cells from whole blood.     

Unzipping and scrambling reaction-induced sequence control of copolymer chains via temperature changes during cationic ring-opening copolymerization of cyclic acetals and cyclic esters

A temperature change-dependent sequence transformation of copolymer chains was demonstrated by a method based on tandem depolymerization and transacetalization reactions during the cationic ring-opening copolymerization of cyclic acetals and cyclic esters. In this study, the position of polymerization-depolymerization equilibrium was controlled by the reaction temperature rather than by the decrease in monomer concentration under vacuum conditions, as in our previous study. First, the conditions for efficient copolymerization were optimized, with a particular focus on the structures of cyclic acetals and cyclic esters. Subsequently, sequence transformation induced by temperature change was examined during the copolymerization of 2-methyl-1,3-dioxepane (generated in situ from 4-hydroxybutyl vinyl ether) and δ-valerolactone using EtSO₃H. The homosequence length of cyclic acetals decreased during depolymerization (unzipping) at the oxonium chain ends upon increasing the temperature from 30 to 90 °C, while transacetalization (scrambling) of the main chain transferred midchain cyclic acetal homosequences to the oxonium chain ends. As a result of the cycle of unzipping and scrambling reactions, an alternating-like copolymer was obtained. Interestingly, the possibility of reversible sequence transformation upon heating and cooling was also demonstrated.     

Preparation of refractive index matching polymer film alternative to oil for use in a portable surface-plasmon resonance phenomenon-based chemical sensor method

In order to simplify the procedure for assembling a surface-plasmon resonance (SPR) sensor, a refractive index matching polymer film was prepared as an alternative to the conventionally used matching oil. The refractive index matching polymer film, the refractive index of which was nearly equal to the prism and sensor chip material (a cover glass) of the SPR sensor, was prepared by casting a tetrahydrofuran solution of poly (vinyl chloride) (PVC) containing equal weights of dioctyl phthalate and tricresyl phosphate. The refractive index matching polymer film was found to have a refractive index of 1.516, which is identical to that of the prism and the cover glass used for the present SPR sensor. The utility of the matching polymer film for the SPR sensor was confirmed by the detection of anti-human albumin, based on an antigen-antibody reaction.     

Positron annihilation studies of heavy-ion induced radiation damages in stainless steels

Variable-energy (0–30 keV) positrons were used to study the depth distribution of heavy-ion induced vacancy type defects in the following specimens, SUS304 and SUS316 austenitic stainless steels, a SUS444 ferritic stainless steel and nickel metal, which were irradiated by 0.5 MeV He⁺, 2.0 MeV C⁺, 3.5 MeV Si²⁺ and 4.0 MeV Ni²⁺ ions up to 0.01 dpa at peak. Vacancy type effective residual defects (ERD) were evaluated from the line shape parameterS of Doppler broadened positron annihilation photon spectra. With increasing primary knockon atom (PKA) energy, a decrease of the vacancy type ERD was observed. The ERD differences among the specimens are discussed in comparison with theoretical predictions.     

Photochemische reaktionen. 108. Mitteilung. Photochemistry of N-acylazoles. VI. Photoreactivities of 1-acyl-1,2,4-triazoles and of 2-acyltetrazoles

Contrary to the findings in the photolysis of N-acylimidazoles [2] irradiation of 1-acyl-1,2,4-triazoles afforded no photo-Fries product, but instead products formed via the corresponding acyl radicals and aldehydes. Photolysis of 2-acyltetrazoles gave in part the same products as those obtained from the irradiation of the corresponding acyl-triazoles as well as 2-alkyl-1,3,4-oxadiazoles. N-Acyltetrazoles didn't give any photo-Fries product neither.     

Ferroelectric and optical properties of Ba6Ti2Nb8O30 single crystals

The dielectric, optical and non-linear optical properties of Ba₆Ti₂Nb₈O₃₀ single crystals were examined from room temperature up to the Curie temperature of 245°C. The spontaneous polarization at room temperature was estimated as 0·22±0·01 C/m². The linear electrooptic constants were measured as r₃₃^T=(1·17±0·02)×10^?10 and r₁₃^T=(0·42±0·01)×10^?10 m/V. The non-linear optical coefficients were d₃₃=(15·1±2·0)×10^?12 and d₃₁=(11·0±2·0)×10^?12 m/V, which are comparable to those of Ba₄Na₂Nb₁₀O₃₀. Temperature dependences of δ₃₃ and δ₃₁ (Miller's δ) were found to be proportional to that of P_s.     

Ring-Opening Polymerization of Ethylene Carbonate Catalyzed with Ionic Liquids: Imidazolium Chloroaluminate and Chlorostannate Melts

Ring-opening polymerization of ethylene carbonate in the presence of ionic liquids, 1-butyl-3-methylimidazolium chloroaluminate melt and 1-butyl-3-methylimidazolium chlorostannate melt, has been investigated. Polymerization takes place accompanied with decarboxylation even at temperatures below 100°C under the reaction conditions selected to give poly(ethylene ether-carbonate)s.