• 제목/요약/키워드: Water chemistry

검색결과 4,424건 처리시간 0.03초

Preparation and Characterization of Water-Dispersible Silver Nanoparticles Stabilized by PEO-Conjugated Pro-Drugs

  • Kim, Tae-Hwan;Kim, Keun-Suk;Park, Geon-Hee;Choi, Jin-Hee;Lee, Sang-Mi;Kang, Ho-Jung;Lee, Jae-Yeol;Kim, Jung-Ahn
    • Macromolecular Research
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    • 제17권10호
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    • pp.770-775
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    • 2009
  • $\omega$-Anhydride-functionalized poly(ethylene oxide) (PEO) obtained from chain-end functionalization and anionic ring-opening polymerization of ethylene oxide using n-butyllithium with potassium t-butoxide in the presence of dimethylsulfoxide (DMSO) was found to be an efficient material for the preparation of water-soluble, polymeric pro-drugs. The reaction of $\omega$-anhydride-functionalized PEO with sulfonamide or with vancomycin provided an efficient method to produce corresponding, water-soluble, PEO-conjugated sulfonamide or PEO-conjugated, vancomycin pro-drugs. These were used successfully to prepare water-dispersible, silver nanoparticles. In this study, the particle sizes were in the range of $5{\sim}40$ nm. The resulting products were characterized by $^1H$ NMR spectroscopy, transmission electron microscopy, electron and X-ray diffraction, size exclusion chromatography, and UV/Visible spectroscopy.

A Simple Phenol‐Indole Dye as a Chromogenic Probe for the Ratiometric Determination of Water Content in Organic Solvents

  • Kim, Kyoung- Nam;Song, Ki-Cheol;Noh, Jae-Hyun;Chang, Suk-Kyu
    • Bulletin of the Korean Chemical Society
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    • 제30권1호
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    • pp.197-200
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    • 2009
  • A simple dye having phenol and indole moieties was synthesized and its chromogenic signaling behaviors for the determination of water content in organic solvents were investigated. The compound revealed a pronounced chromogenic behavior in response to the variation of water content in water miscible aprotic organic solvents of acetone, acetonitrile, THF, and dioxane. Significant red shifts and changes in absorption spectra allowed a ratiometric analysis of the signaling behavior. The chemosensing behaviors were particularly pronounced in water content in less than 10% that is suitable for the application of the compound as a probe for the determination of water content in binary aqueous organic solutions having lower water content.

Computational Study of Proline - Water Cluster

  • Lee, Kyung-Min;Park, Sung-Woo;Jeon, In-Sun;Lee, Bo-Ra;Ahn, Doo-Sik;Lee, Sung-Yul
    • Bulletin of the Korean Chemical Society
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    • 제26권6호
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    • pp.909-912
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    • 2005
  • Calculations are presented for the structures of various conformers of the bare proline and proline –($H_2O$) cluster. The effects of hydrogen bonding with a water molecule on the relative stability of the low energy conformers of proline are examined. Microsolvation by a water molecule is predicted to affect the relative stability, structures and the infrared frequencies of the conformers to a large degree.

Properties of Biodegradable Films Produced from Rice Bran and Roasted Sesame Meal through Chemical Modifications

  • Bae, Dongho;Kim, Woo Jung;Jang, In Sook
    • Journal of Applied Biological Chemistry
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    • 제43권2호
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    • pp.79-85
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    • 2000
  • Biodegradable films were prepared from roasted sesame meal and rice bran. Acetic anhydride, succinic anhydride, and formaldehyde were added to the film-forming solutions, and their effects on tensile strength, percent elongation, water vapor permeability, and water solubility of the films were studied. Roasted sesame meal did not form film without acylation or addition of formaldehyde. Acylated roasted sesame films had higher tensile strength and water-solubility, and lower % elongation than rice bran films. Acylation with acetic and succinic anhydrides increased tensile strength, percent elongation, and water solubility of rice bran films, but decreased water vapor permeability. Treatment with formaldehyde increased tensile strength of roasted sesame and rice bran films and % elongation of rice bran films, while reducing water-solubility of roasted sesame and rice bran films and water vapor permeability of rice bran films.

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