Dielectric relaxation and ionic transport in poly(ethylene carbonate)‐based electrolytes

To study the ion‐conductive and dielectric properties of polymer electrolytes based on poly(ethylene carbonate) (PEC) with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the complex permittivity and conductivity were measured using broadband dielectric spectroscopy. The temperature dependence of the relaxation frequency and ionic conductivity for PEC‐LiTFSI electrolytes (1 – 200 mol%) indicates that the segmental motion of PEC chains decreases with the addition of just 1 mol% of Li salt and increases with increasing concentration above 10 mol%. According to the Walden rule for PEC‐based electrolytes, the value of deviation from the reference line increased, and the fragility and decoupling exponents decreased with increasing salt concentration. These results indicate that there are large numbers of ion pairs and aggregated ions, which imply low ionicity and reduced fragility in highly concentrated PEC‐based electrolytes. Copyright © 2016 John Wiley & Sons, Ltd.     

Aggregation behavior of amphiphilic random copolymer of 2‐(acrylamido)‐2‐methylpropanesulfonic acid and tris(trimethylsiloxy)silylpropylmethacrylate in aqueous solution

Aggregation behavior including dilute solution property and surface‐activity of the amphiphilic random copolymer composed of 2‐(acrylamido)‐2‐methylpropanesulfonic acid and tris(trimethylsiloxy)silylpropylmethacrylate (AMPS/TRIS copolymer) in aqueous solution were studied by static light scattering (SLS), dynamic light scattering (DLS), surface tension measurement, and transmission electron microscopy (TEM). The surface tension measurement made it clear that AMPS/TRIS copolymer exhibited weaker surface‐activity than a typical low‐molecular weight surfactant sodium dodecyl sulfate in water, that is, there were no plateau of surface tension γ versus concentration and no critical micelle concentration (CMC) in the whole concentration studied. SLS and DLS analyses, and TEM revealed that AMPS/TRIS copolymer self‐associated into imperfect core‐shell micelles having hydrophobic TRIS core surrounded by hydrophilic AMPS shell in water. AMPS shell was considered as a hard shell due to the stiffness of AMPS chain in water. TRIS chain could not densely aggregate in water due to the large steric hindrance between bulky trimethylsiloxy groups despite its hydrophobic nature, thereby providing TRIS core with less‐dense structure. The balance between the spreading force of stiff AMPS chain and the cohesion force of bulky TRIS chain provides the driving force for forming the unique micelle having less‐dense TRIS core and hard AMPS shell. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Enhanced Green Fluorescent Protein Expression in Pleurotus ostreatus for In Vivo Analysis of Fungal Laccase Promoters

The laccase family of Pleurotus ostreatus has been widely characterized, and studies of the genes coding for laccase isoenzymes in P. ostreatus have so far led to the identification of four different genes and the corresponding cDNAs, poxc, pox1, poxa1b and poxa3. Analyses of P. ostreatus laccase promoters poxc, pox1, poxa1b and poxa3 have allowed identification of several putative response elements, and sequences of metal-responsive elements involved in the formation of complexes with fungal proteins have been identified in poxc and poxa1b promoters. In this work, development of a system for in vivo analysis of P. ostreatus laccase promoter poxc by enhanced green fluorescent protein expression is performed, based on a poly ethylene glycol-mediated procedure for fungal transformation. A quantitative measurement of fluorescence expressed in P. ostreatus transformants is hereby reported for the first time for this fungus.     

Binary mass diffusion in smectic C and CA phases as observed by forced Rayleigh scattering

Abstract

We have observed the diffusion constants of a dye in several liquid crystals by forced Rayleigh scattering. In a liquid crystal which has a standard phase sequence of N-S_A-S_C, the diffusion anisotropy changes at the N-S_A phase transition and increases with decreasing temperature in S_A and S_C phases. The diffusion constants exhibit a rather smooth decrease with decreasing temperature except an anomaly at the S_A-S_c phase transition. In a liquid crystal which has the antiferroelectric S_CA phase, however, the diffusion constants show discontinuous increase and decrease at the S_A-S_c and the S_c-S_cA phase transition temperatures, respectively: the diffusion constant in S_C is larger than that in the higher temperature S_A phase. Anomalous signal increase and profile were observed at the phase transition temperatures, and were ascribed to the complementary transient grating due to the coexistence of two phases.     

Amphiphilic taper-shaped oligomer exhibiting a monolayer smectic A to columnar phase transition

We prepared two series of liquid-crystalline oligomers composed of phenylpyrimidine based mesogenic cores, alkyl spacers and semiperfluorinated alkyl chains in one series and only alkyl chains in the second series. Their physical properties were investigated using optical microscopy, differential scanning calorimetry and X-ray diffraction measurements. The oligomers possessing a semiperfluorinated alkyl chain show a phase sequence of SmC–SmA–Col when the number of phenylpyrimidine moieties was increased. The compound possessing three phenylpyrimidine cores was found to exhibit monolayer SmA and Col phases. On the other hand, the oligomer composed of an alkyl chain and three phenylpyrimidine cores showed only a nematic phase. We discuss effects of the shape amphiphilicity and the hydrocarbon–fluorocarbon amphiphilicity on phase transition behaviour of the amphiphilic oligomers.     

Preparation and properties of novel thermotropic liquid crystalline hyperbranched polyesters composed of five‐membered heterocyclic mesogen by A2 + B3 approach

New thermotropic liquid crystalline (LC) hyperbranched (HB) polyesters containing 2,5‐diphenyl‐1,3,4‐thiadiazole (DTD) unit as mesogen in the interiors were prepared at various mole ratios (A₂/B₃) by melt and solution polycondensations of a dioxydiundecanol of DTD (A₂) and 1,2,3‐propanetricarboxylic acid (B₃) via the A₂ + B₃ approach and their LC and optical properties were investigated. FTIR and ¹H‐NMR spectroscopies indicated that all the expected HB polyesters, which show good solubilities in organic solvents, are produced without gelation during the polymerization. Among them, the HB polymer prepared in the mole ratio of A₂/B₃ = 3/2 by the solution polycondensation had the highest inherent viscositiy. DSC measurents, polarizing microscope observations of optical textures, and X‐ray analyses suggested that the LC properties of HB polymers depend on the polymerization methods and the feed mole ratios. In the HB polymers prepared using the melt polycondensation, only the polymer prepared in the mole ratio of A₂/B₃ = 3/1 formed a highly‐ordered, tilted, crystal‐like smectic phase, but all the polymers prepared by the solution polycondensation formed highly‐ordered, tilted, smectic phases. Solution and solid‐state UV‐vis and photoluminescent (PL) spectra indicated that the HB polymers show maximum absorbances and blue‐light emission on the basis of the DTD unit, where the Stokes‐shifts were observed, probably because of intermolecular aggregation effects © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2998–3008, 2007     

Antitumor Activity of Vinyl Polymer Immobilized 5-Fluorouracils through Organosilicon-Amine Spacer Groups via Urea Bonds

Abstract

The homopolymerization of vinyl monomer immobilized 5-fluorouracils (5FU) through organosilicon-amine spacer groups via urea bonds (KY-20) and the copolymerization of KY-20 with vinyl monomer were carried out by a radical technique to give the homopolymer [Poly(KY-20)] and copolymer [Poly(KY-20/vinyl monomer)], respectively. The antitumor activities of Poly(KY-20) and Poly(KY-20/vinyl monomer) were tested against p388 lymphocytic leukemia by intraperitoneal (i.p.) transplantation/i.p. or oral (p.o.) administration and against Meth-A fibrosarcoma or MM46 mammary adenocarcinoma in mice by subcutaneous (s.c.) implantation/p.o. administration. These 5FU/ organosilicon-amine hybrid polymer conjugates exhibited significant survival effects against p388 leukemia in mice i.p./i.p. or i.p./p.o. Poly(KY-20/HPMA) also showed stronger growth-inhibitory effects against Meth-A fibrosarcoma and MM46 mammary adenocarcinoma in mice s.c./p.o.     

Numerical method for verifying the existence and local uniqueness of a double turning point for a radially symmetric solution of the perturbed Gelfand equation

A numerical verification method to confirm the existence and local uniqueness of a double turning point for a radially symmetric solution of the perturbed Gelfand equation is presented. Using certain systems of equations corresponding to a double turning point, we derive a sufficient condition for its existence whose satisfaction can be verified computationally. We describe verification procedures and give a numerical example as a demonstration.