The antibacterial activity of methanol extract from the root bark of Akanda (Calotropis gigantea L.) and its petroleum ether, chloroform and ethyl acetate fractions were investigated. Both of methanol extract and its chloroform fraction showed activity against Sarcina lutea, Bacillus megaterium and Pseudomonas aeruginosa. Petroleum ether fraction showed activity against Bacillus subtilis and Shigella sonnei whereas ethyl acetate fraction showed activity against Pseudomonas aeruginosa and Escherichia coli at 20µg/disc, 30µg/disc and 40µg/disc doses. Among the tested materials, methanol extract and its chloroform fraction showed comparatively better results. Minimum inhibitory concentration (MIC) for methanol extract and each fraction were also determined by serial dilution technique.

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Dual‐responsive micrometer‐sized core‐shell composite polymer particles were prepared by dispersion polymerization followed by seeded copolymerization. Polystyrene (PS) particles prepared by dispersion polymerization were used as core particles. N‐isopropyl acrylamide (NIPAM) and methacrylic acid (MAA) were used to induce dual‐responsive that is thermo‐ and pH‐responsive properties in the shell layer of composite polymer particles, prepared by seeded copolymerization with PS core particles. Temperature‐ and pH‐dependent adsorption behaviors of some macromolecules on composite polymer particles indicate that produced composite polymer particles exhibit dual‐responsive surface properties. Copyright © 2007 John Wiley & Sons, Ltd.

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