Nano-segregated polymeric film exhibiting high ionic conductivities

Nanostructures can be used for the fabrication of highly functional materials transporting ions and charges. We demonstrate a new design strategy for polymeric higher ion-conductors. Phase-segregated layers of alternating mobile tetra(ethylene oxide)s (TEOs) and rigid aromatic cores where the TEO moieties are grafted from aromatic layers have been shown to be efficient to transport lithium triflate. Such segregated structures at the nanometer scale (nano-segregated structures) were prepared by in-situ photopolymerization of an aligned methacrylate liquid crystalline monomer comprising a terphenyl rigid rod mesogen having a TEO terminal chain. The ion-conductive TEO moiety remains in the highly mobile state even after polymerization, which is indicated by its low glass transition temperature (-45 degrees C). This nanostructured film exhibits an ionic conductivity parallel to the layer of 10(-3) S cm(-1) at room temperature. The highest ionic conductivity is in the level of 10(-2) S cm(-1) observed at 150 degrees C. The anisotropic ionic conductivities have been observed for the nano-segregated film.     

Pulse injection analysis of the binding of serum proteins to porous polymer gels modified with formyl groups

Highly porous spherical polymer gels were modified with formyl groups by a modified Friedel-Crafts reaction and the interaction of serum proteins with the modified gels were examined by pulse injection analysis. The introduction of formyl groups into the polymer greatly increases its protein-binding capacity, and the protein bound to the gel is not eluted by washing with acid, alkali or urea solution. The effects of temperature and the percentage of formyl group substitution on the binding capacity indicate that the binding process can be interpreted as initial approach of the protein to the polymer surface, caused by the hydrophobic interaction, followed by formation of a stable Schiff base between the polymer gel and the protein. Theoretical treatment of the elution behaviour of the protein from the polymer-packed column is also examined, with the assumption that there are three kinds of binding site in the polymer gel: surface, macropore and micropore regions. These polymers are shown to be useful for the removal of proteins from biological samples in clinical assays using immobilized enzymes.     

Synthetic study of 1-substituted carbapenem antibiotics

Total synthesis of 1-substituted carbapenems is described. The key step is the reaction of acetoxyazetidinone ($\text{7}$) with ketene silyl acetal ($\text{8}$).     

Metal-organic thin-film transistor (MOTFT) based on a bis(o-diiminobenzosemiquinonate) nickel(II) complex

The semiconducting film based on bis(o-diiminobenzosemiquinonate) nickel(II) complex showed uniaxial orientation structure along the normal to the substrate and good p-type metal-organic thin-film transistor (MOTFT) character.     

Synthesis of quinoxaline 1,4-dioxides from 4,5(6,7)-dimethylbenzofuroxan

In this study, novel substituted quinoxaline 1,4-dioxides were synthesized from novel substituted benzofuroxan. 4,5(6,7)-Dimethylbenzofuroxan 3 was prepared by the thermal decomposition of 2,3-dimethyl-6-nitrophenylazide 2 . Novel quinoxaline 1,4-dioxides derivatives were obtained using compound 3 and the enolic form of 1,3-diketones 4 catalyzed by silica gel or molecular sieves. These reactions gave isomeric quinoxaline 1,4-dioxides 5 and 6 . These reactions of compound 3 may involve tautomers 4,5-dimethylbenzofuroxan 3a , 6,7-dimethylbenzofuroxan 3b on the surface of a solid catalyst.     

Synthesis of oligonucleotide inhibitor of protein synthesis: pppA2′p5′A2′p5′A

Oligoadenylates with 2′–5′ linkage were prepared in aqueous solution catalyzed by lead nitrate. Phosphorylation of the resulting triadenylate gave oligonucleotide inhibitor of protein synthesis, ppA2′p5′A2′p5′A.     

Solvent extraction of lead,silver, antimony and thallium with zinc dibenzyldithiocarbamate and its application to the separation of bismuth from large amounts of lead

Solvent extraction of lead, silver, antimony and thallium from various acid solutions was investigated with zinc-DBDTC as chelating reagent. These metals were quantitatively extracted over a wide range of acidity with 0.03% zinc-DBDTC solution in carbon tetrachloride. A separation procedure for bismuth from large amounts of lead was developed; bismuth was extracted from 1 M nitric acid with zinc-DBDTC and was separated from lead by subsequently washing the organic phase once with 3.5 M hydrochloric acid or twice with 3 M hydrochloric acid. Satisfactory results were obtained in separating microgram amounts of bismuth from 1 g of lead.     

A strained InAIAs/InGaAs superlattice avalanche photodiode with a waveguide structure for low bias-voltage operation

An InAIAs/InGaAs superlattice (SL) multiplication layer operating at an IC-power supply voltage was realized by introducing strain into the SL. Using this SL as an absorption and multiplication layer, edge-coupled InAIAs/InGaAs SL avalanche photodiodes with waveguide structures were demonstrated. An avalanche multiplication factor larger than 10 was achieved at a bias voltage of less than 7V. A wide 3 dB bandwidth of 8 GHz was obtained at a multiplication factor of 3 and a wavelength of 1.3 m.     

Silica monolithic membrane as separation medium. Summable property of different membranes for high-performance liquid chromatographic separation

We studied an applicability of a silica monolithic membrane as separation medium for high-performance liquid chromatography (HPLC). We prepared porous monolithic silica membranes having a three-dimensional network structure to cut and shape into a membrane separation medium. We evaluated chromatographic properties of a variety of solutes using a column containing the membranes with HPLC to elucidate summable property of the membrane separation media. In addition, we made brief study on separation of HbA1c in whole blood with the stacked" membranes having different surface characteristics in one column, which is a membrane column. We confirmed that the membrane column was able to separate HbA1c from other matrix in whole blood to some extent, and it also had an excellent ability for hydrophobic and ion exchange adsorption.     

Dielectrophoretic micropatterning with microparticle monolayers covalently linked to glass surfaces

Two-dimensional micropatterns of microparticles were fabricated on glass substrates with negative dielectrophoretic force, and the patterned microparticles were covalently bound on the substrate via cross-linking agents. The line and grid patterns of microparticles were prepared using the repulsive force of negative dielectrophoresis (n-DEP). The template interdigitated microband array (IDA) electrodes (width and gap 50 mum) were incorporated into the dielectrophoretic patterning cell with a fluidic channel. The microstructures on the glass substrates with amino or sulfhydryl groups were immobilized with the cross-linking agents disuccinimidyl suberate (DSS) and m-maleimidobenzoyl-N-hydroxy-succinimide ester (MBS). Diaphorase (Dp), a flavoenzyme, was selectively attached on the patterned microparticles using the maleimide groups of MBS. The enzyme activity on the patterned particles was electrochemically characterized with a scanning electrochemical microscope (SECM) in the presence of NADH and ferrocenylmethanol as a redox mediator. The SECM images proved that Dp was selectively immobilized onto the surface of microparticles to maintain its catalytic activity.