The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform

Masao Suzuki - One of the best experts on this subject based on the ideXlab platform.

  • formation of reverse hexagonal phase in water Polyoxyethylene Oleyl Ether system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999
    Co-Authors: Yoko Yamaguchi, Kazuyo Ozawa, Masao Suzuki
    Abstract:

    Abstract In Polyoxyethylene Oleyl Ether–water systems, an effective cross-sectional area per surfactant molecule at a hydrophobic interface of liquid crystal can be geometrically calculated from the interlayer spacing d of the liquid crystal. As is expected, as increases with increasing the EO-chain length due to the increase of the hydration repulsion between the hydrophilic moieties. Consequently, the structures of surfactant self-assemblies transform from reverse hexagonal (H2) to normal hexagonal (H1) phases via a lamellar structure (Lα). The magnitude of as is determined by the balance between attractive (interfacial tension) and repulsive (hydration) forces acting at the hydrophobic interfaces of the aggregates. The H2 phase is only observed in the very narrow region of EO-chain length, and the estimated as values are almost independent with increasing surfactant concentration. According to the theory of the local free energy of the surfactant, the negative curvature of the H2 phase would lead to the increase of the chemical potential μ because the EO chains must be closely packed. This increase of μ, however, is probably compensated by the rather decrease of attraction force between the hydrophobic parts with curvature. With increase of EO chain length, the increase of repulsion force becomes dominant the reduction of attraction force, and finally the H2–Lα phase transition takes place. The theory which the curvature effect is considered can well explain the change of as in the water–Oleyl surfactant systems.

  • phase behavior of Polyoxyethylene Oleyl Ether in water
    Progress in colloid and polymer science, 1997
    Co-Authors: Kazuki Shigeta, Masao Suzuki
    Abstract:

    Phase behavior of penta-deca- and eicosa-oxyethylene Oleyl Ether in water were investigated. Differently from ordinary Oleyl surfactants, the lipophilic chains of the present surfactants consist of pure Oleyl group. The basic feature of the phase behavior extremely resembles that of pure Polyoxyethylene hexadecyl Ether systems although the solid present regions in the Oleyl surfactant systems are very narrow due to the low melting point of Oleyl group.

Hong-xia Liu - One of the best experts on this subject based on the ideXlab platform.

  • Surfactant Supplementation to Enhance the Production of Vitamin K2 Metabolites in Shake Flask Cultures Using Escherichia sp. Mutant FM3-1709
    University of Zagreb, 2014
    Co-Authors: Yan Liu, Hong-wei Qiu, Gen-hai Zhao, Peng Wang, Hui Liu, Li Wang, Hong-xia Liu, Mu Tan
    Abstract:

    The effects of the addition of various surfactants on the cell growth and production of vitamin K2 metabolites, such as intracellular menaquinone-4 (MK-4), extracellular MK-4, intracellular MK-6 and extracellular MK-6, were studied in the submerged culture of Escherichia sp. All of the added surfactants caused the extension of the exponential phase. Betaine, Polyoxyethylene Oleyl Ether and Tween-80 were favourable to the cell growth of Escherichia sp. mutant strain FM3-1709. The highest cell growth (Xmax), biomass production rate (Qx) and biomass yield (Yx/s) were (12.6±0.2) g/L, (0.21±0.01) g/(L·h) and (2.42± 0.02) g/g, respectively. The results show that the addition of all surfactants led to a lower production of intracellular MK-4, whereas the production of extracellular MK-4 increased remarkably. Among the five investigated surfactants, the addition of the nonionic surfactant Polyoxyethylene Oleyl Ether (1.0 g/L) led to the highest production of extracellular MK-4 ((33.6±0.4) mg/L), MK-6 ((2.56±0.07) mg/L) and the highest yield of total MK-4 ((47.6±0.4) mg/L) and MK-6 ((6.0±0.1) mg/L). The addition of Polyoxyethylene Oleyl Ether proved to be more beneficial for the secretion of MK-4 than MK-6

  • Surfactant Supplementation to Enhance the Production of Vitamin K2 Metabolites in Shake Flask Cultures Using Escherichia sp. Mutant FM3-1709
    Faculty of Food Technology and Biotechnology University of Zagreb, 2014
    Co-Authors: Yan Liu, Hong-wei Qiu, Gen-hai Zhao, Peng Wang, Hui Liu, Li Wang, Zhi-ming Zheng, Hong-xia Liu
    Abstract:

    Ispitan je utjecaj dodatka različitih surfaktanata na rast stanica i proizvodnju metabolita vitamina K2, poput unutarstaničnih i izvanstaničnih menakinona MK-4 i MK-6, pri submerznom uzgoju bakterije Escherichia sp. Svi su surfaktanti produljili eksponencijalnu fazu rasta bakterije. Betain, polioksietilen oleil eter i Tween-80 povoljno su djelovali na rast stanica mutanta bakterije Escherichia sp. FM3-1709. Najveći je rast stanica bio Xmax=(12,6±0,2) g/L, najveća stopa proizvodnje biomase Qx=(0,21±0,01) g/(L·h), a najveći prinos biomase YX/S=(2,42±0,02) g/g. Rezultati pokazuju da se dodatkom surfaktanata smanjila proizvodnja unutarstaničnog MK-4, dok se proizvodnja izvanstaničnog MK-4 bitno povećala. Od pet ispitanih surfaktanata, najbolji su rezultati postignuti dodatkom neionskog surfaktanta polioksietilen oleil etera (1,0 g/L), pri čemu je koncentracija izvanstaničnog MK-4 bila (33,6±0,4) mg/L, a izvanstaničnog MK-6 (2,56±0,07) mg/L, dok je ukupni prinos MK-4 bio (47,6±0,4) mg/L, a MK-6 (6,0±0,1) mg/L. Dodatak je polioksilen oleil etera djelovao puno povoljnije na lučenje MK-4, nego na lučenje MK-6.The effects of the addition of various surfactants on the cell growth and production of vitamin K2 metabolites, such as intracellular menaquinone-4 (MK-4), extracellular MK-4, intracellular MK-6 and extracellular MK-6, were studied in the submerged culture of Escherichia sp. All of the added surfactants caused the extension of the exponential phase. Betaine, Polyoxyethylene Oleyl Ether and Tween-80 were favourable to the cell growth of Escherichia sp. mutant strain FM3-1709. The highest cell growth (Xmax), biomass production rate (Qx) and biomass yield (Yx/s) were (12.6±0.2) g/L, (0.21±0.01) g/(L·h) and (2.42± 0.02) g/g, respectively. The results show that the addition of all surfactants led to a lower production of intracellular MK-4, whereas the production of extracellular MK-4 increased remarkably. Among the five investigated surfactants, the addition of the nonionic surfactant Polyoxyethylene Oleyl Ether (1.0 g/L) led to the highest production of extracellular MK-4 ((33.6±0.4) mg/L), MK-6 ((2.56±0.07) mg/L) and the highest yield of total MK-4 ((47.6±0.4) mg/L) and MK-6 ((6.0±0.1) mg/L). The addition of Polyoxyethylene Oleyl Ether proved to be more beneficial for the secretion of MK-4 than MK-6

Yan Liu - One of the best experts on this subject based on the ideXlab platform.

  • Surfactant Supplementation to Enhance the Production of Vitamin K2 Metabolites in Shake Flask Cultures Using Escherichia sp. Mutant FM3-1709
    University of Zagreb, 2014
    Co-Authors: Yan Liu, Hong-wei Qiu, Gen-hai Zhao, Peng Wang, Hui Liu, Li Wang, Hong-xia Liu, Mu Tan
    Abstract:

    The effects of the addition of various surfactants on the cell growth and production of vitamin K2 metabolites, such as intracellular menaquinone-4 (MK-4), extracellular MK-4, intracellular MK-6 and extracellular MK-6, were studied in the submerged culture of Escherichia sp. All of the added surfactants caused the extension of the exponential phase. Betaine, Polyoxyethylene Oleyl Ether and Tween-80 were favourable to the cell growth of Escherichia sp. mutant strain FM3-1709. The highest cell growth (Xmax), biomass production rate (Qx) and biomass yield (Yx/s) were (12.6±0.2) g/L, (0.21±0.01) g/(L·h) and (2.42± 0.02) g/g, respectively. The results show that the addition of all surfactants led to a lower production of intracellular MK-4, whereas the production of extracellular MK-4 increased remarkably. Among the five investigated surfactants, the addition of the nonionic surfactant Polyoxyethylene Oleyl Ether (1.0 g/L) led to the highest production of extracellular MK-4 ((33.6±0.4) mg/L), MK-6 ((2.56±0.07) mg/L) and the highest yield of total MK-4 ((47.6±0.4) mg/L) and MK-6 ((6.0±0.1) mg/L). The addition of Polyoxyethylene Oleyl Ether proved to be more beneficial for the secretion of MK-4 than MK-6

  • Surfactant Supplementation to Enhance the Production of Vitamin K2 Metabolites in Shake Flask Cultures Using Escherichia sp. Mutant FM3-1709
    Faculty of Food Technology and Biotechnology University of Zagreb, 2014
    Co-Authors: Yan Liu, Hong-wei Qiu, Gen-hai Zhao, Peng Wang, Hui Liu, Li Wang, Zhi-ming Zheng, Hong-xia Liu
    Abstract:

    Ispitan je utjecaj dodatka različitih surfaktanata na rast stanica i proizvodnju metabolita vitamina K2, poput unutarstaničnih i izvanstaničnih menakinona MK-4 i MK-6, pri submerznom uzgoju bakterije Escherichia sp. Svi su surfaktanti produljili eksponencijalnu fazu rasta bakterije. Betain, polioksietilen oleil eter i Tween-80 povoljno su djelovali na rast stanica mutanta bakterije Escherichia sp. FM3-1709. Najveći je rast stanica bio Xmax=(12,6±0,2) g/L, najveća stopa proizvodnje biomase Qx=(0,21±0,01) g/(L·h), a najveći prinos biomase YX/S=(2,42±0,02) g/g. Rezultati pokazuju da se dodatkom surfaktanata smanjila proizvodnja unutarstaničnog MK-4, dok se proizvodnja izvanstaničnog MK-4 bitno povećala. Od pet ispitanih surfaktanata, najbolji su rezultati postignuti dodatkom neionskog surfaktanta polioksietilen oleil etera (1,0 g/L), pri čemu je koncentracija izvanstaničnog MK-4 bila (33,6±0,4) mg/L, a izvanstaničnog MK-6 (2,56±0,07) mg/L, dok je ukupni prinos MK-4 bio (47,6±0,4) mg/L, a MK-6 (6,0±0,1) mg/L. Dodatak je polioksilen oleil etera djelovao puno povoljnije na lučenje MK-4, nego na lučenje MK-6.The effects of the addition of various surfactants on the cell growth and production of vitamin K2 metabolites, such as intracellular menaquinone-4 (MK-4), extracellular MK-4, intracellular MK-6 and extracellular MK-6, were studied in the submerged culture of Escherichia sp. All of the added surfactants caused the extension of the exponential phase. Betaine, Polyoxyethylene Oleyl Ether and Tween-80 were favourable to the cell growth of Escherichia sp. mutant strain FM3-1709. The highest cell growth (Xmax), biomass production rate (Qx) and biomass yield (Yx/s) were (12.6±0.2) g/L, (0.21±0.01) g/(L·h) and (2.42± 0.02) g/g, respectively. The results show that the addition of all surfactants led to a lower production of intracellular MK-4, whereas the production of extracellular MK-4 increased remarkably. Among the five investigated surfactants, the addition of the nonionic surfactant Polyoxyethylene Oleyl Ether (1.0 g/L) led to the highest production of extracellular MK-4 ((33.6±0.4) mg/L), MK-6 ((2.56±0.07) mg/L) and the highest yield of total MK-4 ((47.6±0.4) mg/L) and MK-6 ((6.0±0.1) mg/L). The addition of Polyoxyethylene Oleyl Ether proved to be more beneficial for the secretion of MK-4 than MK-6

Yoko Yamaguchi - One of the best experts on this subject based on the ideXlab platform.

  • formation of reverse hexagonal phase in water Polyoxyethylene Oleyl Ether system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999
    Co-Authors: Yoko Yamaguchi, Kazuyo Ozawa, Masao Suzuki
    Abstract:

    Abstract In Polyoxyethylene Oleyl Ether–water systems, an effective cross-sectional area per surfactant molecule at a hydrophobic interface of liquid crystal can be geometrically calculated from the interlayer spacing d of the liquid crystal. As is expected, as increases with increasing the EO-chain length due to the increase of the hydration repulsion between the hydrophilic moieties. Consequently, the structures of surfactant self-assemblies transform from reverse hexagonal (H2) to normal hexagonal (H1) phases via a lamellar structure (Lα). The magnitude of as is determined by the balance between attractive (interfacial tension) and repulsive (hydration) forces acting at the hydrophobic interfaces of the aggregates. The H2 phase is only observed in the very narrow region of EO-chain length, and the estimated as values are almost independent with increasing surfactant concentration. According to the theory of the local free energy of the surfactant, the negative curvature of the H2 phase would lead to the increase of the chemical potential μ because the EO chains must be closely packed. This increase of μ, however, is probably compensated by the rather decrease of attraction force between the hydrophobic parts with curvature. With increase of EO chain length, the increase of repulsion force becomes dominant the reduction of attraction force, and finally the H2–Lα phase transition takes place. The theory which the curvature effect is considered can well explain the change of as in the water–Oleyl surfactant systems.

Toyohide Takeuchi - One of the best experts on this subject based on the ideXlab platform.

  • determination of iodide in seawater using c30 column modified with Polyoxyethylene Oleyl Ether in ion chromatography
    Talanta, 2007
    Co-Authors: Li Rong, Toyohide Takeuchi
    Abstract:

    Abstract An ion chromatographic method for rapid and direct determination of iodide in seawater samples is reported. Separation was achieved using a laboratory-made C30 packed column (100 mm × 0.32 mm i.d.) modified with Polyoxyethylene Oleyl Ether, with an aqueous solution of 300 mM sodium chloride as eluent and using UV detection at 220 nm. Samples containing iodate, nitrate, iodide and thiocyanate were eluted within 8 min, and the relative standard deviations of the retention time, peak area and peak height were all smaller than 4.19% for all of the analyte anions. Effects of eluent composition on retention behavior of inorganic anions have been investigated. Both cation and anion of the eluent affected the retention time of analytes. When inorganic eluents, such as ammonium chloride, ammonium sulfate, lithium chloride, sodium chloride, sodium sulfate, magnesium chloride and magnesium sulfate were used, the retention time of analytes increased with increasing eluent concentration. The limit of detection of iodide was 19 μg l−1 (S/N = 3), while the limit of quantitation was 66 μg l−1 (S/N = 10). The present method was successfully applied to the rapid and direct determination of iodide in seawater samples.