One-pot conversion of levan prepared from Serratia levanicum NN to difructose anhydride IV by Arthrobacter nicotinovorans levan fructotransferase

The newly established difructose anhydride IV (DFA IV) production system is comprised of the effective production of levan from sucrose by Serratia levanicum NN, the conversion of the levan into DFA IV by levan fructotransferase from Arthrobacter nicotinovorans GS-9, which is highly expressed in an Escherichiacoli transformant, and a practical purification step. The chemical properties of DFA IV were also investigated.     

Synthesis of structurally well-controlled ω-vinylidene functionalized poly(alkyl methacrylate)s and polymethacrylonitrile by organotellurium,organostibine, and organobismuthine-mediated living radical polymerizations

The reaction of poly(methyl methacrylate) (PMMA), poly(i-butyl methacrylate), poly(2-hydroxyethyl methacrylate), and polymethacrylonitrile bearing organotellurium, organostibine, and organobismuthine ω-living polymer end groups with 2,2,6,6-tetramethylpiperidine 1-oxy (TEMPO) under thermal or photochemical conditions gave the corresponding ω-vinylidene functionalized polymethacrylates and polymethacrylonitrile with high end group fidelity. Treatment of the PMMA with ethyl 2-[(tributylstannyl)methyl]acrylate also gave a PMMA bearing the same ω-vinylidene end functionality. ¹H NMR, GPC, MALDI TOF MS, and thermogravimetric analyses revealed the highly controlled and defined structure of poly(alkyl methacrylate)s and polymethacrylonitrile in terms of molecular weight, molecular weight distribution, and the ω-polymer end structure.     

Enzymatic synthesis of kojioligosaccharides using kojibiose phosphorylase

We have attempted to synthesize kojioligosaccharides (oligosaccharides having the alpha-1,2 glycosidic linkage at the nonreducing end) using two methods. In the first, mixtures of various proportions of glucose and beta-D-glucose-1-phosphate (beta-G1P) were allowed to react in the presence of kojibiose phosphorylase (KPase). In the second, maltose was allowed to react with KPase and maltose phosphorylase (MPase) simultaneously. In the former method, kojioligosaccharides having only the alpha-1,2 glucosidic linkage were synthesized and the average degree of polymerization (D.P.) of oligosaccharides increased with decreasing proportions of glucose. In the second method, kojioligosaccharides were obtained at approximately 70% yields under optimum conditions. 4-alpha-D-Kojibiosyl-glucose, kojitriose and kojitetraose, the principal kojioligosaccharides synthesized, were not hydrolyzed by salivary amylase, artificial gastric juice, pancreatic amylase, or small intestinal enzymes.     

n-3 long-chain FA decrease serum levels of TG and remnant-like particle-cholesterol in humans

A large number of papers have reported that administration of n−3 FA reduced serum TG concentrations in hypertriglyceridemic patients. However, few studies have examined the effect of n−3 FA on serum concentrations of remnant-like particle (RLP) cholesterol. Volunteers (n=41) whose serum TG concentrations were 100–300 mg/dL were recruited and randomly assigned to either an n−3 FA group or a control group with stratification by sex, age, and serum TG level in a double-blind manner. The subjects in the n−3 FA group were administered 125 ml of fermented soybean milk with fish oil containing 600 mg of EPA and 260 mg of DHA/d for 12 wk. The controls consumed control soybean milk with olive oil. Fasting blood samples were obtained before the start of administration and at 4, 8 and 12 wk. EPA concentrations in red blood cells increased significantly in all but one subject in the n−3 FA group, with no significant changes in the control group. TG levels decreased more in the n−3 FA group than in the control group at weeks 4 (P<0.05), 8 (P<0.01), and 12 (P<0.05) with their baseline as covariate. RLP cholesterol levels decreased more in the n−3 FA group than in the control at weeks 8 (P<0.01) and 12 (P<0.05) with their baseline as covariate. The groups did not differ in the other lipid levels. It is likely that n−3 long-chain FA may exert anti-atherosclerotic effects by lowering serum TG and RLP-cholesterol levels even at the dose of 860 mg/d.     

Pressure effect on CHF enhancement in pool boiling of nanofluids

This paper investigates critical heat flux (CHF) in saturated pool boiling for water and TiO₂ nanofluid on a 7-mm-diameter vertical copper surface at pressures of 0.1–0.8 MPa. The nanofluid was prepared by dispersing 0.002 wt% TiO₂ nanoparticles in deionized water. The CHF of the nanofluid was enhanced about two times over that of water boiling at atmospheric pressure. With the increasing pressure, however, the CHF enhancement with the nanofluid decreases, and almost disappears at 0.8 MPa.     

Low‐temperature fabrication of 5‐in. QVGA flexible AMOLED display driven by OTFTs using olefin polymer as the gate insulator

Abstract— A 5‐in. QVGA flexible AMOLED display driven by OTFTs has been fabricated at a low temperature of 130°C. A polyethylene naphthalate film was used as the flexible substrate and an olefin polymer was used as the gate insulator for the OTFT. This layer was formed by spin‐coating and baking at 130°C. Pentacene was used as the organic semiconductor layer. The OTFT performance to drive the flexible display with QVGA pixels in terms of current on/off ratio, carrier mobility, and spatial uniformity on the backplane have been obtained. Phosphorescent and fluorescent OLEDs were used as light‐emitting devices on a flexible display. Those layers were formed by vacuum deposition. After the flexible display was fabricated, a clear and uniform moving image was obtained on the display. The display also showed a stable moving image even when it was bent.     

Improvement in image quality of a 5.8‐in. OTFT‐driven flexible AMOLED display

Abstract— The image quality of an OTFT‐driven flexible AMOLED display has been improved by enhancing the performance of OTFTs and OLEDs. To reduce the operating voltage of OTFTs on a plastic film, Ta²O⁵ with a high dielectric constant was used as a gate insulator. The organic semiconductor layer of the OTFT was successfully patterned by a polymer separator, which is an isolating wall structure using an organic material. The OTFT performance, such as its current on/off ratio, carrier mobility, and spatial uniformity on the backplane, was enhanced. A highly efficient phosphorescent OLED was used as a light‐emission device. A very thin molybdenum oxide film was introduced as a carrier‐injection layer on a pixel electrode to reduce the operating voltage of the OLED. After an OTFT‐driven flexible AMOLED display was fabricated, the luminance and uniformity on the display was improved. The fabricated display also showed clear moving images, even when it was bent at a low operating voltage.     

gBoost: a mathematical programming approach to graph classification and regression

Graph mining methods enumerate frequently appearing subgraph patterns, which can be used as features for subsequent classification or regression. However, frequent patterns are not necessarily informative for the given learning problem. We propose a mathematical programming boosting method (gBoost) that progressively collects informative patterns. Compared to AdaBoost, gBoost can build the prediction rule with fewer iterations. To apply the boosting method to graph data, a branch-and-bound pattern search algorithm is developed based on the DFS code tree. The constructed search space is reused in later iterations to minimize the computation time. Our method can learn more efficiently than the simpler method based on frequent substructure mining, because the output labels are used as an extra information source for pruning the search space. Furthermore, by engineering the mathematical program, a wide range of machine learning problems can be solved without modifying the pattern search algorithm.     

Remarks on the assignments of temperature programmed desorption peaks for the surface species formed on Cu/ZnO and ZnO in the methanol synthesis from CO

Temperature programmed desorption (TPD), IR spectroscopy and chemical trapping of the surface species with H₂O revealed that the TPD peak of CO frequently assigned to zinc formate species, which were formed in the course of the methanol synthesis from CO-H₂, arose from zinc methoxide species.     

Lipase made active in hydrophobic media by coupling with polyethylene glycol

Lipases from various microorganisms were chemically modified with polyethylene glycol derivatives: 2,4-bis[O-methoxypoly(ethylene glycol)]-6-chloro-s-triazine (activated PEG₂, a chain-shaped polymer) and copolymer of polyoxyethylene allyl methyl diether and maleic anhydride (activated PM, a comb-shaped polymer). Because each polymer is amphipathic, the modified lipases become soluble not only in aqueous solution but also in hydrophobic media. They exhibit potent catalytic actions for ester synthesis and ester exchange reactions, the reverse reaction of hydrolysis, in transparent organic solvents and also in oily substrates without organic solvents. With PEG₂-lipases, macrocyclic lactone and gefarnate (geranyl farnesylacetate) were synthesized in high yields from 16-hydroxy-hexadecanoic acid ethyl ester and from farnesylacetic acid and geraniol in organic solvents, respectively. The modified lipase catalyzed the esterification preferentially with the (R)-isomer of secondary alcohols. Because the ester synthesis reactions with modified lipase proceeded in the transparent benzene system, the kinetic parameters (Michaelis constant and maximum velocity) were obtained by reciprocal plotting according to the Michaelis equation. With comb-shaped polymer as modifier, PM-lipase catalyzed effectively the reverse reaction of hydrolysis in organic solvents. The properties of each modified lipase are discussed in relation to those of the nonmodified lipase. Presented at the 84th Annual Meeting of the American Oil Chemists' Society held on April 25–29, 1993, in Anaheim, CA.