Reactivity of quinones for the dehydrogenation of poly(1,3‐cyclohexadiene)

The reactivity of three types of quinones (3,4,5,6‐tetrachloro‐1,2‐(o‐)‐benzoquinone (TOQ), 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ), and 2,3,5,6,‐tetrachloro‐1,4‐(p‐)‐benzoquinone (TCQ)) was examined for the dehydrogenation of poly(1,3‐cycohexadiene) (PCHD) composed of 1,2‐cyclohexadiene and 1,4‐cyclohexadiene units. The order of reactivity was TOQ > DDQ > TCQ. The steric hindrance of C?O groups in the quinones appeared to be an important factor in determining their reactivity. DDQ was found to be an appropriate dehydrogenation reagent for PCHD. The reactivity of TCQ was considerably low for PCHD containing 1,2‐cyclohexadiene units. The reactivity of TOQ was too high and side reactions occurred, causing the formation of structural defects. Copyright © 2007 Society of Chemical Industry     

Soluble polyphenylene homopolymers with controllable microstructure and properties: Optical and electrical characteristics of completely dehydrogenated poly(1,3-cyclohexadiene) as a π-conjugated polymer semiconductor

The optical and electrical characteristics of soluble polyphenylene (PPH) homopolymers obtained by the complete dehydrogenation of poly(1,3-cyclohexadiene) (PCHD) are reported for the first time. The optical properties were strongly affected by the molar ratios of 1,2-/1,4-phenylene (Ph) units. The HOMO and LUMO energy levels were approximately −5.2 and −2.0 eV, and the microstructure did not influence those energy levels or the band gap energies. The generation of carriers (both electron and hole) in the polymer films was observed, and the drift mobility of electrons and holes was affected by the molar ratios of 1,2-/1,4-Ph units in the polymer chain. The drift mobility of electrons in PPH homopolymers with a high content of 1,4-Ph units was in the order of 10⁻⁴ to 10⁻⁵ (cm²/Vs). The I-V characteristics of soluble PPH homopolymers were controllable by the microstructure of PPH. The 1,2-Ph unit imparted appropriate solubility and toughness to the PPH homopolymers.     

Sugar-Induced Chiral Orientation of Boronic-Acid-Appended Amphiphile Clusters Formed in the Dipalmitoylphosphatidylcholine (DPPC) Membrane

A boronic-acid-appended amphiphile bearing an azobenzene chromophore in the chain center ( 3 ) was synthesized. Although 3 could not form the membrane-like, ordered aggregate by itself, it formed a phase-separated aggregate in a dipalmitoylphosphatidylcholine (DPPC) matrix membrane. When saccharides were added, the boronic acid group reversibly formed the saccharide complexes, and 3 in the DPPC matrix membrane became CD-active with the appearance of exciton-coupling bands. Comparison of the saccharide absolute configuration with the CD intensity established that the saccharide possessing the OH group (as 3-OH, 4-OH, and 5-CH₂OH) in the same side as the cis-1,2-diol gives the strong CD band. Judging from the structure of 3 –saccharide complexes, these “same-side” OH groups can enjoy intermolecular hydrogen-bonding interactions, which eventually induce the chiral orientation of azobenzene chromophores. This is a novel membrane system useful to read out the information stored in the saccharide structure and to create novel membrane structures by added saccharides.     

A novel protease in the pupal yellow body of Sarcophaga peregrina (flesh fly). Its purification and cDNA cloning

We purified a novel serine protease with a molecular mass of 26 kDa from Sarcophaga pupae. This protease appeared almost exclusively in the yellow body, an organ that develops temporarily in the pupae of dipteran insects and expands to form the adult midgut by engulfing the larval midgut. cDNA analysis revealed that this protease consists of 239 amino acid residues and has significant structural similarity with bovine trypsin (about 40% sequence identity). The 26-kDa protease gene was transiently activated in 1-day-old pupae. The protease was found to cross-react immunologically with antibody against sarcotoxin IA, an antibacterial protein produced by this insect. It is suggested that this protease participates in the decomposition of the larval midgut in the yellow body during metamorphosis.     

The dispersion of a sound velocity near the phase transition point of csd2PO4

The relaxation time τ of the polarization fluctuation is obtained from the frequency dependence of the sound velocity in MHz region. The value of τ is the order of 10 nsec just below the phase transition point and agrees with that obtained from the dispersion of the dielectric constant.     

Detection of Leuconostoc strains at a meat processing plant using polymerase chain reaction

To simplify the labor-intensive conventional routine testing of samples to detect Leuconostoc at a meat processing plant, we developed polymerase chain reaction (PCR) primers specific for Leuconostoc from 16S rRNA gene sequences. These primers did not detect other common lactic acid bacteria such as Lactobacillus plantarum, Lact. sake, Lact. fermentum, Lact. acidophilus and Weissella viridescens. PCR with this primer detected all Leuconostoc species tested (Leu. mesenteroides subsp. mesenteroides, Leu. pseudomesenteroides, Leu. carnosum, Leu. lactic, Leu. citreum, Leu. amelibiosum, Leu. gelidum), except for Leu. fallax, and no other lactic acid bacteria on agarose gel electrophoresis. The method could identify areas contaminated with Leuconostoc in a large-scale industrial meat processing plant. Of 69 samples analyzed, 34 were positive for Leuconostoc according to the conventional culture method (isolation of LAB producing dextran) and PCR, whereas 29 were negative according to both. Six samples were culture-negative but positive by PCR. No false negative results were generated by PCR. The method is rapid and simple, is useful for routinely monitoring areas contaminated with Leuconostoc in meat processing plants, and could help to prevent the spoilage of meat products.     

Rapid discharge performance of composite electrode of hydrated sodium manganese oxide and acetylene black

Hydrated sodium manganese oxide was synthesized by reducing permanganate ion using ethanol by a sol–gel method. By including acetylene black in the synthetic reaction, we obtained composite materials in which sodium manganese oxide hydrate particles were small and mixed well with the acetylene black. We evaluated those composites as a lithium battery cathode and found that they showed 170 mA h g⁻¹ under 5 mA g⁻¹ and 117 mA h g⁻¹ under 5 A g⁻¹ on the basis of composite weight. This rapid discharge performance was probably caused by the favorable contact condition of the composite constituents.     

PCE-based fast path control in multi-domain photonic networks

We discuss issues for controlling an optical path in large-scale photonic networks, and introduce an inter-domain path control system based on Path Computation Elements (PCEs). In the system, maximum flow information enables the load balancing of traffic, and Path Key scheme preserve the confidentiality of internal topology information among carrier networks. Based on the experimental results, we show the path setup in the introduced system is significantly faster than the manual path setup among domains in current carriers' networks. For the additional reduction of the path setup time, we propose the domain-wise paralleled signaling method. We also show that decreasing the number of nodes per domain makes path setup faster in the introduced system with deployment of the proposed signaling method.