The Experts below are selected from a list of 141 Experts worldwide ranked by ideXlab platform
Marieta Nichifor - One of the best experts on this subject based on the ideXlab platform.
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Novel biodegradable flocculanting agents based on cationic amphiphilic polysaccharides.
Bioresource technology, 2010Co-Authors: Luminita Ghimici, Marieta NichiforAbstract:Flocculation properties of a series of cationic polysaccharides, with N-alkyl-N,N-dimethyl-N-(2-hydroxypropyl)ammonium chloride pendent Groups attached to a dextran backbone, were evaluated in clay dispersions with respect to length of the alkyl substituent, molar mass, the charge density, and polycation dose. According to turbidimetric results, the alkyl chain length greatly influenced the optimum polymer dose as well as the width of the flocculation window since both increased from an ethyl to a butyl Group and decreased for when octyl or Dodecyl Group was present. The residual turbidity values also varied with the charge density but no dramatic effect was observed with the molar masses investigated. These findings together with the negative value of the zeta potential at the optimum polymer dose and floc size measurements, point to contributions from both patch and bridging mechanisms for the flocculation process.
Luminita Ghimici - One of the best experts on this subject based on the ideXlab platform.
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Novel biodegradable flocculanting agents based on cationic amphiphilic polysaccharides.
Bioresource technology, 2010Co-Authors: Luminita Ghimici, Marieta NichiforAbstract:Flocculation properties of a series of cationic polysaccharides, with N-alkyl-N,N-dimethyl-N-(2-hydroxypropyl)ammonium chloride pendent Groups attached to a dextran backbone, were evaluated in clay dispersions with respect to length of the alkyl substituent, molar mass, the charge density, and polycation dose. According to turbidimetric results, the alkyl chain length greatly influenced the optimum polymer dose as well as the width of the flocculation window since both increased from an ethyl to a butyl Group and decreased for when octyl or Dodecyl Group was present. The residual turbidity values also varied with the charge density but no dramatic effect was observed with the molar masses investigated. These findings together with the negative value of the zeta potential at the optimum polymer dose and floc size measurements, point to contributions from both patch and bridging mechanisms for the flocculation process.
Tjoon Tow Teng - One of the best experts on this subject based on the ideXlab platform.
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Comparative study on the effectiveness of hydrophobically modified cationic polyacrylamide Groups in the flocculation of kaolin
Desalination, 2011Co-Authors: Khai Ern Lee, Norhashimah Morad, Beng Teik Poh, Tjoon Tow TengAbstract:Abstract A series of hydrophobic cationic monomers were introduced into acrylamide chain to form hydrophobically modified cationic polyacrylamide. The hydrophobic cationic monomer used in this study was 3-acrylamido-2-hydroxypropyltrialkylammonium chloride (AHPTAAC) in which the alkyl Groups were hexyl, octyl and Dodecyl Groups. The characteristics of the copolymers were tuned by varying the mole ratios of the hydrophobic cationic monomers (1–6 mol %) to obtain copolymers of different molecular weights and charge densities. The effects of hydrophobically modified cationic polyacrylamides, with different hydrophobic cationic Groups, molecular weights and charge densities, on flocculation of kaolin suspension, were investigated. A significant inverse correlation was found between molecular weight and charge density. The effects of different hydrophobic Groups and monomer substitution ratios on the kaolin turbidity removal were compared. Hexyl Group copolymer, which had the highest molecular weight of 2.13 × 10 6 g/mol, was able to reduce 99% of kaolin suspension turbidity through flocculation. 1 mol % of hydrophobic Group associated copolymers was found to be the best system in flocculating kaolin suspension, and bridging was the dominant mechanism in flocculating kaolin suspension. Copolymer with the Dodecyl Group had the least water retention in the flocculated sludge.
Shinsuke Yamashita - One of the best experts on this subject based on the ideXlab platform.
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Monolayer of Poly(l-glutamate) with an n-Dodecyl Group in the Side Chain on the Water Surface and Its Multilayers
Langmuir, 1998Co-Authors: Akira Shibata, Satoru Ueno, Yoshihiro Ito, Shinsuke YamashitaAbstract:The conformation and monolayer assembly of poly(γ-n-Dodecyl l-glutamate) (PDOLG) in a monolayer at the air−water interface and its multilayers were investigated by surface film balance, FTIR, and electron microscopy methods. PDOLG with long alkyl side chains formed a condensed type monolayer with an α-helical conformation. The hysteresis loop in the compression−expansion−recompression isotherms indicated that relaxation processes were operating in the monolayer. PDOLG molecules formed a polygonal network structure in the multilayer film prepared at the pressure 20 mN/m by the lifting method.
Yi-wen Liu - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and In Vitro Photocytotoxicity of 9-/13-Lipophilic Substituted Berberine Derivatives as Potential Anticancer Agents.
Molecules (Basel Switzerland), 2020Co-Authors: Hong-jhih Lin, Li-chen Tsai, Fang-yu Yang, Ling-ling Yang, Cheng-deng Kuo, Lih Geeng Chen, Yi-wen LiuAbstract:The objective of this study was to synthesize the 9-/13-position substituted berberine derivatives and evaluate their cytotoxic and photocytotoxic effects against three human cancer cell lines. Among all the synthesized compounds, 9-O-Dodecyl- (5e), 13-Dodecyl- (6e), and 13-O-Dodecyl-berberine (7e) exhibited stronger growth inhibition against three human cancer cell lines, (HepG2, HT-29 and BFTC905), in comparison with structurally related berberine (1). These three compounds also showed the photocytotoxicity in human cancer cells in a concentration-dependent and light dose-dependent manner. Through flow cytometry analysis, we found out a lipophilic Group at the 9-/13-position of berberine may have facilitated its penetration into test cells and hence enhanced its photocytotoxicity on the human liver cancer cell HepG2. Further, in cell cycle analysis, 5e, 6e, and 7e induced HepG2 cells to arrest at the S phase and caused apoptosis upon irradiation. In addition, photodynamic treatment of berberine derivatives 5e, 6e, and 7e again showed a significant photocytotoxic effects on HepG2 cells, induced remarkable cell apoptosis, greatly increased intracellular ROS level, and the loss of mitochondrial membrane potential. These results over and again confirmed that berberine derivatives 5e, 6e, and 7e greatly enhanced photocytotoxicity. Taken together, the test data led us to conclude that berberine derivatives with a Dodecyl Group at the 9-/13-position could be great candidates for the anti-liver cancer medicines developments.
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Synthesis and in vitro Photocytotoxicity of 9-/13-lipophilic Substituted Berberine Derivatives as Potential Anticancer Agents
2020Co-Authors: Hong-jhih Lin, Li-chen Tsai, Fang-yu Yang, Ling-ling Yang, Cheng-deng Kuo, Lih Geeng Chen, Yi-wen LiuAbstract:The objective of this study was to synthesize 9-/13-position substituted berberine derivatives and evaluated their cytotoxic and photocytotoxic effects against three human cancer cell lines. Among all the synthesized compounds, 9-O-Dodecyl- (5e), 13-Dodecyl- (6e) and 13-O-Dodecyl-berberine (7e) exhibited stronger growth inhibition against three human cancer cell lines, (HepG2, HT-29 and BFTC905), in compare with structurally related berberine (1). These three compounds also showed the photocytotoxicity in human cancer cells in a concentration-dependent and light dose-dependent manner. Through flow cytometry analysis, we found out a lipophilic Group at 9-/13-position of berberine may have facilitated its penetration into test cell and hence enhanced its photocytotoxicity on human liver cancer cell HepG2. Further, in cell cycle analysis, 5e, 6e and 7e induced HepG2 cells to arrest at S phase and caused apoptosis upon irradiation. In addition, photodynamic treatment of berberine (1) and its derivatives 5e, 6e and 7e again showed a significant photocytotoxic effects on HepG2 cells, induced remarkable cell apoptosis, greatly increased intracellular ROS level and the loss of mitochondrial membrane potential. These results over and again confirmed that berberine derivatives 5e, 6e and 7e greatly enhanced photocytotoxicity. Taking together, the test data led us to conclude that berberine derivatives with a Dodecyl Group at 9-/13-position could be great candidates for the anti-liver cancer medicines developments.