n-Hexyl Laurate and Fourteen Related Fatty Acid Esters: New Secretory Compounds from the Julid Millipede, Anaulaciulus sp.

A total of fifteen saturated fatty acid esters were newly identified from the secretions of an unidentified Anaulaciulus sp. (Julida: Julidae). The fatty acid components of the esters were composed of normal chain acids (from C₁₀ to C₁₄) and of branched chain acids (from iso-C₁₂ to iso-C₁₅ and anteiso-C₁₅). The alcohol moieties were all composed of normal chain alcohols varying from n-butanol to n-octanol. The most abundant component found in the total esters was n-hexyl laurate (64.7%). Novel compounds identified from the millipede secretion extracts include six branched iso- and anteiso-fatty esters, an odd-numbered C₁₁-fatty acid ester, a C₁₃-fatty acid ester, and a C₇-alcohol ester, all of which were previously undescribed natural products. In addition, a characteristic mixture of benzoquinones, such as 2-methyl-1,4-benzoquinone, 2-methoxy-3-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, 2-methoxy-6-methyl-1,4-benzoquinone, and 2,3-dimethoxy-5-methyl-1,4-benzoquinone were identified from the secretions, together with trace amounts of 1,4-benzoquinone.     

Steam Reforming of Methanol on Copper Catalysts Supported on Large-Surface-Area ZnAl2O3

Steam reforming of methanol on various supported Cu catalysts was examined. Supports strongly affected catalyst activity and, among the catalysts tested, Cu catalyst supported on large-surface-area ZnAl₂O₄ showed the highest activity, which, to the best of our knowledge, was higher than those for the supported catalysts reported so far. For supported Cu catalysts, two species were observed. One was a dispersed Cu species having strong interaction between Cu and support, and the other was an isolated Cu species. The activity of the former species strongly depended on supports.     

Fluoroscent properties of 22,24-diprotonated 5,10,15,20-tetrakis (4-sulfonatophenyl)porphyrin interacting with a β-sheet structure of a zwitterionic polypeptide

Summary The fluorescent properties of 22,24-Diprotonated 5,10,15,20-Tetrakis(4-sulfonatophenyl)porphyrin interacting with the β-sheet structure of a zwitterionic Poly(Glu-Val-Lys-Val) were investigated under various conditions. The TPPS diacid species formed four types of aggregated species by the addition of the polypeptide and/or NaCl. The fluorescent bands were observed for the monomeric and their three aggregated species. The fluorescent intensity changes and maximum wavelength shifts indicated that the monomeric and their aggregated species bound to the polypeptide by electrostatic interaction. The poly(Glu-Val-Lys-Val)/TPPS diacid species system may be provided a good model for studying the porphyrin assembly binding to specific protein domains with definite orientations and alignments. Received: 16 November 2001/Revised version: 14 December 2001/Accepted: 21 December 2001     

Oxidation kinetics for <Emphasis Type="Italic">cis</Emphasis>-9,<Emphasis Type="Italic">trans</Emphasis>-11 and <Emphasis Type="Italic">trans</Emphasis>-10,<Emphasis Type="Italic">cis</Emphasis>-12 isomers of CLA

The autoxidation processes of the cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic-type rate expression, but the latter half followed first-order kinetics. On the other hand, the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic-type rate expression. The apparent activation energies and frequency factors for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested that the autoxidation mechanisms for the CLA and PUFA were essentially the same.     

High temperature catalytic combustion of methane and propane over hexaaluminate catalysts: NOx emission characteristics

Several hexaaluminate-related materials were prepared via hydrolysis of alkoxide and powder mixing method for high temperature combustion of CH₄ and C₃H₈, in order to investigate the effect of the concentration of the fuels, O₂ and H₂O on NO_x emission and combustion characteristics. Among the hexaaluminate catalysts, Sr_0.8La_0.2MnAl₁₁O₁₉₋ prepared by the alkoxide method exhibited the highest activity for methane combustion and low NO_x emission capability. NO_x emission at 1500 °C was increased linearly with O₂ concentration, whereas water vapor addition decreased NO_x emission in CH₄ combustion over the Sr_0.8La_0.2MnAl₁₁O₁₉₋ catalyst. In the catalytic combustion of C₃H₈ over the Sr_0.8La_0.2MnAl₁₁O₁₉₋ catalyst, the amount of NO_x emitted was raised in the temperature range between 1000 and 1500 °C when the C₃H₈ concentration increased from 1 to 2 vol.%. It was found that NO_x emission in this temperature range was reduced effectively by adding water vapor.     

Boronic acid‐based thin films that show saccharide‐responsive multicolor changes

A novel saccharide sensor that displays a distinct color change resembling a “traffic signal” was developed. By copolymerizing boronic acid and amine monomers on a glass plate, a boronic acid‐containing thin film was obtained. Anionic blue and yellow dyes were adsorbed on the thin film, and the film was immersed in aqueous saccharide solutions containing a cationic red dye. With increase in the saccharide concentration in the solution, the thin film changes color from green to red via yellow. The observed distinct changes in color were attributed to a stepwise release and binding of dyes. The sensitivity of the saccharide sensor was dependent on the monomer composition of the thin film and increased with increasing the boronic acid content. The pH of the saccharide solution was another key factor affecting the sensing behavior, and glucose‐responsive color changes were significantly enhanced at pH 7.8. By optimizing these conditions, significant color changes in response to glucose were achieved. Saccharide selectivity was found to be in the following order: fructose > glucose > galactose = mannose > sucrose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42679.     

Predicting nitrogen leaching with the modified LEACHM model: validation in soils receiving long-term application of animal manure composts

A variety of process-based models have been developed for predicting nitrogen (N) dynamics in agro-ecosystem; however, no reliable models have been validated for N leaching from soils receiving a long-term application of different types of animal manure composts. The Leaching Estimation and Chemistry Model (LEACHM) was recently modified by incorporating the basic structure of Rothamsted Carbon Model for extending its ability to describe soil organic matter decomposition and subsequent N leaching in soils rich in organic matter. We evaluate the applicability of the modified LEACHM in cropped Yellow soils receiving 10-year application of cattle or swine manure compost in addition to chemical fertilizers, where high-frequency field monitoring data of soil water contents, soil N contents and leachate N concentrations were available for the last 3 years. Particular attention was paid to determine all input parameters from independent measurements, parameterization from known soil properties or databases without optimisation to fit the measured field data. The model reasonably predicted temporal changes in the soil NH₄-N and NO₃-N contents, and inorganic N concentrations in the leachate as well as their differences due to different manure compost/chemical fertilizer applications. The simulations of leached N concentration yielded a Willmott index of agreement (IA) of 0.62–0.68, with those for soil moisture, soil nitrate content and crop N uptake all within an acceptable IA range. In view of the good performance without site-specific calibrations, the modified LEACHM appears to be a valuable tool for predicting N leaching from cropped soils receiving long-term manure compost applications.     

A Unique Amino Transfer Mechanism for Constructing the β‐Amino Fatty Acid Starter Unit in the Biosynthesis of the Macrolactam Antibiotic Cremimycin

Cremimycin is a 19‐membered macrolactam glycoside antibiotic based on three distinctive substructures: 1) a β‐amino fatty acid starter moiety, 2) a bicyclic macrolactam ring, and 3) a cymarose unit. To elucidate the biosynthetic machineries responsible for these three structures, the cremimycin biosynthetic gene cluster was identified. The cmi gene cluster consists of 33 open reading frames encoding eight polyketide synthases, six deoxysugar biosynthetic enzymes, and a characteristic group of five β‐amino‐acid‐transfer enzymes. Involvement of the gene cluster in cremimycin production was confirmed by a gene knockout experiment. Further, a feeding experiment demonstrated that 3‐aminononanoate is a direct precursor of cremimycin. Two characteristic enzymes of the cremimycin‐type biosynthesis were functionally characterized in vitro. The results showed that a putative thioesterase homologue, CmiS1, catalyzes the Michael addition of glycine to the β‐position of a non‐2‐enoic acid thioester, followed by hydrolysis of the thioester to give N‐carboxymethyl‐3‐aminononanoate. Subsequently, the resultant amino acid was oxidized by a putative FAD‐dependent glycine oxidase homologue, CmiS2, to produce 3‐aminononanoate and glyoxylate. This represents a unique amino transfer mechanism for β‐amino acid biosynthesis.     

Cationic polymerization of hydrogenated bisphenol‐A glycidyl ether with cycloaliphatic epoxy resin and its thermal discoloration

One of the key issues associated with epoxy resin–based LED encapsulant is discoloration under operating conditions that caused a decrease in light output. In this article, thermal cationic polymerization of hydrogenated bisphenol‐A glycidyl ether using 3‐methyl‐2‐butenyltetramethylenesulfonium hexafluoroantimonate and its discoloration are reported. Polymerization was followed by thermal analysis, FT‐IR spectrum, and hardness measurements. Thermal discoloration was measured by yellowness index based on transmittance spectrum. Increased catalyst concentration causes acceleration in polymerization rates, but this also increased discoloration after thermal aging. In low catalyst concentration under 0.3 wt %, the hardness of plaque was low and required a high temperature to complete polymerization and this resulted in a highly colored plaque. Formulation with cycloaliphatic epoxy (3′‐4′‐epoxycyclohexane)methyl 3′‐4′‐epoxycyclohexyl‐carboxylate (CEL2021P) enhanced the polymerization even at low catalyst concentration and reduced thermal discoloration. With addition of di‐t‐butylphenol (BHT) as the oxidation inhibitor, the thermal discoloration was extremely improved but this also caused inhibition of polymerization as seen by thermal analysis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1395–1400, 2005     

Photoanodic response of iron oxide electrode in aqueous solution and its application to Pb removal under visible light irradiation

The iron oxide electrode was prepared from thermal oxidation of iron at 600 °C for 3 h in air atmosphere. This electrode with the structure of Fe₃O₄ and α-Fe₂O₃ showed the response of photoanodic current to the light with wavelength shorter than 600 nm. The band gap energy of this electrode was 1.99 eV. The onset potential of distinct steady photocurrent and also the flatband potential were 0.80 and 0.09 V vs. Ag/AgCl, respectively, in 0.1 M HNO₃ aqueous solution. The cell consisting of the iron oxide photoanode in HNO₃-Pb(NO₃)₂ and the graphite cathode in H₂SO₄-Ce(SO₄)₂ caused the PbO₂ deposit on the surface of the former electrode due to visible light irradiation without application of voltage. By holding the potential of this electrode at more positive value than 0.90 V, the photoanodic removal rate of Pb²⁺ in HNO₃-Pb(NO₃)₂ solution was higher than that observed when Ce⁴⁺ was used as electron acceptor.