Functional metallomacrocycle derivatives and their polymers. 31. Preparation and electrochromic properties of novel cobaltophathalocyanine thin films on electrodes

A novel cobaltphthalocyaninanine compound was deposited as a thin film on an indium/tin oxide-coated (ITO) glass electrode by electrodeposition from a solution of 2,9,16,23-tetracarboxyphthalocyaninatocobalto(II) [Co(II)-taPc] and CaCl₂ in DMF. Electrochromic properties of the thin film were investigated. Formation of a calcium chelate complex between Co(II)-taPc and Ca²⁺ and deposition as a thin film on the electrode was confirmed by IR and XMA measurements. Cyclic voltammogram and electron absorption spectra were carried out. Electrochemical reduction and oxidation of CoPc thin films showed a rapid, virtually quantitative reversible process in electrochromism (blue-green-brown). No change in voltammogram was observed after >10,000 cycles.     

A flexible OLED display with an OTFT backplane made by scalable manufacturing process

Abstract— A full‐color top‐emission AMOLED display driven by an organic TFT backplane manufactured using a scalable, lift‐off‐free, and shadow‐mask‐free process has been developed. It was shown that cost‐efficient copper can be used for S/D electrodes. The display has shown no significant degradation over a storage life of more than 10 months and operation over 25 hours during which the display is bent over 10,000 times.     

Apatite-forming ability of vinylphosphonic acid-based copolymer in simulated body fluid: effects of phosphate group content

Phosphate groups on materials surfaces are known to contribute to apatite formation upon exposure of the materials in simulated body fluid and improved affinity of the materials for osteoblast-like cells. Typically, polymers containing phosphate groups are organic matrices consisting of apatite–polymer composites prepared by biomimetic process using simulated body fluid. Ca²⁺ incorporation into the polymer accelerates apatite formation in simulated body fluid owing because of increase in the supersaturation degree, with respect to apatite in simulated body fluid, owing to Ca²⁺ release from the polymer. However, the effects of phosphate content on the Ca²⁺ release and apatite-forming abilities of copolymers in simulated body fluid are rather elusive. In this study, a phosphate-containing copolymer prepared from vinylphosphonic acid, 2-hydroxyethyl methacrylate, and triethylene glycol dimethacrylate was examined. The release of Ca²⁺ in Tris-NaCl buffer and simulated body fluid increased as the additive amount of vinylphosphonic acid increased. However, apatite formation was suppressed as the phosphate groups content increased despite the enhanced release of Ca²⁺ from the polymer. This phenomenon was reflected by changes in the surface zeta potential. Thus, it was concluded that the apatite-forming ability of vinylphosphonic acid-2-hydroxyethyl methacrylate-triethylene glycol dimethacrylate copolymer treated with CaCl₂ solution was governed by surface state rather than Ca²⁺ release in simulated body fluid.     

Electrocatalysis Characteristics of a Polynuclear Cyanide Complex, Ruthenium Purple, for Dihydrogen Oxidation

An electrocatalytic dihydrogen oxidation was found to take place on an electrode coated with iron(III) ruthenocyanide (i.e., repeating unit cell structure: Fe^III ₄[Ru^II(CN)₆]₃ or MFe^III[Ru^II(CN)₆] and M = alkali metal counter ion) called ruthenium purple (RP). It was shown by voltammetric study that an electrocatalytic dihydrogen oxidation is induced on oxidizing the Fe^II ion in the cyanometallate. When the electrocatalysis characteristics of RP were investigated by voltammetry, especially in terms of the kinds of electrolyte used (K⁺ or Na⁺), RP exhibited a more efficient electrocatalysis in the K⁺ than in the Na⁺ electrolyte system. While a one-electron electro-oxidation of Fe^II to Fe^III occurs, there is also a release of hydrated alkali metal cation(s) from the anionic RP (i.e., reduced RP) to compensate for charge. Moreover, cation transport through the cyanometallate network is more facile for the K⁺ electrolyte system (cf., size of hydrated cation: Na⁺ at 0.36 nm lattice channel of RP at 0.35 nm > K⁺ at 0.24 nm). Therefore, it was most probable that the present electrocatalysis is kinetically dominated by the electro-oxidation.     

An efficient fabrication of vertically aligned carbon nanotubes on flexible aluminum foils by catalyst-supported chemical vapor deposition

An efficient and versatile growth of thin-layer carbon nanotubes on a flexible aluminum foil (for kitchen use) by catalyst-supported chemical vapor deposition is reported. The aluminum foil used in the present experiment is commercially available for kitchen use. The electron-beam vapor deposition and dip-coating have been used for preparing catalysts on the aluminum foil. Vertically aligned thin-layer CNTs with typical diameters of 2.5-6.0?nm and lengths up to 90?μm are obtained when ethanol is used in combination with Fe and Co catalyst particles at a growth temperature of around 650?°C under an Ar/H(2) gas flow. Thermo-gravimetric analyses together with HR-TEM observations indicate that the purity of the CNTs synthesized by the current technique is very high.     

Apatite-forming ability of polyglutamic acid hydrogels in a body-simulating environment

Artificial joints can replace damaged joints provided the surrounding bone is sufficiently dense. However, elderly patients generally have reduced osteoporosis-associated bone density. Therefore, restitution of bone density is essential to ensure implantation. Injectable and resorbable bioactive fillers with bone-bonding ability (osteoconductivity) are promising, as osteoporosis can be reversed with minimal invasion. Osteoconduction occurs through the surface formation of biologically active hydroxyapatite via reactions with body fluids. Heterogeneous nucleation of the hydroxyapatite is catalysed by specific surface functional groups. In addition, release of Ca²⁺ ions into the surrounding fluids enhances apatite nucleation by increasing its degree of supersaturation. We tested injectable bioactive filler made from cross-linked polyglutamic acid (PGA). This has many carboxyl groups that facilitate apatite nucleation. An insoluble hydrogel can be formed by cross-linkage. We exposed PGA gels to a simulated body fluid for 7 days. Trace amounts of calcium phosphate were formed, but were not identified as bone-like apatite by X-ray diffraction. However, formation of a bone-like apatite layer was detected using pre-treatment with CaCl₂ solutions (>0.01 mol dm⁻³) dose dependently. Thus, this chemically cross-linked PGA gel could induce the heterogeneous nucleation of hydroxyapatite in a body environment, and this was enhanced by pre-treatment with CaCl₂.     

Role of chiral amine cocatalysts in the helix-sense-selective polymerization of a phenylacetylene using a catalytic system

We have examined the role of the chiral amine cocatalyst in the recently discovered helix-sense-selective polymerization of a phenylacetylene using a catalytic system consisting of an achiral rhodium complex ([Rh(norbornadiene)Cl]₂) as the catalyst and a chiral amine as the cocatalyst. Several chiral amines were effective for the polymerization reaction and their effectiveness depended on their bulkiness and coordination ability to rhodium. The sense selectivity of the polymerization increased with the concentration of the chiral amines. To discuss the structure of the true active species in the catalytic system, we have synthesized a new chiral rhodium complex having two chiral amines as ligands ([Rh(norbornadiene)(chiral amine)₂]⁺BF₄⁻). The isolated chiral complex also catalyzed the helix-sense-selective polymerization. These findings suggest that a chiral rhodium complex having two chiral amines may be the true active species when using the catalytic system consisting of [Rh(norbornadiene)Cl]₂ and a chiral amine.     

Enhancement of oxygen permselectivity of polydimethylsiloxane-b-polycarbonate film by the surface modification with fluorine-containing polymer

Summary Both oxygen permeability coefficient(^PO₂) and separation factor ( = ^PO₂/^PN₂) through polydimethylsiloxane-b-polycarbonate(PDMS/PC) film were improved by the addition of small amounts(1.0 wt%) of the fluorine-containing polymer. This improvement was considered to be caused by the selective solubilization of oxygen in the surfaceaccumulated fluorine polymer domain.     

Synthetic genes for human muscle-type adenylate kinase in Escherichia coli

An artificial gene coding for the human muscle-type cytosolicadenylate kinase (hAK1) was chemically synthesized and directlyexpressed in Escherichia coli under the control of trp promoter.The DNA duplex of 596 bp was designed and constructed from 40oligonucleotide fragments of typically 30 nucleotides in length.Twelve unique restriction sites were fairly evenly spaced inthe synthetic gene to facilitate site-specific mutagenesis atany part of this recombinant protein. The genes for mutant hAK1(Tyr 95 – Phe 95, Y95F hAK1; Arg 97 – Ala 97, R97AhAK1) were constructed by cassette mutagenesis and utilizedrestriction sites incorporated in the hAK1 gene. The recombinanthAK1 was purified to homogeneity by a two-step chromatographicprocedure with a good yield, and showed the same adenylate kinaseactivity as that of authentic hAK1. preliminary kinetic studiesshow that the enzymatic activity (V_{max app,cor})     

Effect of fly ash on autogenous shrinkage

The correlation between autogenous shrinkage and degree of hydration of fly ash was determined with the selective dissolution method. Then, the relationship between the degree of hydration of fly ash and autogenous shrinkage was examined. The results showed that the degree of hydration of fly ash increased as its Blaine surface area increased. The degree of hydration of fly ash increased with time, and autogenous shrinkage increased corresponding to the increase in the degree of hydration of fly ash. Moreover, it was found that the total quantity of Al₂O₃ in cement-fly ash samples affected autogenous shrinkage at early ages, but the long-term influence was very small.