• Title/Summary/Keyword: chelates

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Preparation and Characteristics of $\gamma-LiAlO_2$ Fibers by the Sol-Gel Method (졸-겔 법에 의한 $\gamma-LiAlO_2$ 화이버의 제조 및 특성)

  • 현상훈;홍성안;신현철
    • Journal of the Korean Ceramic Society
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    • v.32 no.2
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    • pp.197-208
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    • 1995
  • ${\gamma}$-LiAlO2 fibers for fiber reinforced molten carbonate fuel cell (MCFC) matrix have been produced from LiAlO2 complex polymeric sols using the sol-gel process. The stable and spinnable LiAlO2 sols could be synthesized by mixing LiNO3 alcohol solutions in aluminum complex polymeric sols prepared through the condensationpolymerization reaction of 1 more of aluminum tri-sec-butoxide with 0.55 mole of mixed chelates (mole ratio of acetylaceton/triethanolamine=0.25/0.3). It was found that the viscosity range for fiber-spinning should be higher than 30 poise. The defect-free flexible ${\gamma}$-LiAlO2 fibers with the average tensile strength of 350 MPa could be obtained when the spinned fibers were heat-treated to 120$0^{\circ}C$ on the specified heating schedule after dried at room temperature.

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Effects of pH on Purification of GFPuv/Cytochrome c-552 Fusion Protein

  • Lee, Sang-On;Hong, Eul-Jae;Choe, Jeong-U;Hong, Eok-Gi
    • 한국생물공학회:학술대회논문집
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    • 2003.04a
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    • pp.539-542
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    • 2003
  • Fusion gene of GFPuv and Cytochrome c-552 was inserted into the pTrcHis B vector and transferred to E. coli. A fusion protein of GFPuv and Cytochrome c-552 was expressed in BL21. This fusion protein was composed of a His-tag for purification using an immobilized metal affinity chromatography(IMAC). IMAC constitutes a rather facile means of unravelling the principles of recognition and, in particular, of identifying the counterligands on the protein surface, which interact with the ligated and immobilized metal ions. Histidine when present on the surface of a protein molecule under a favorable solvent condition, may serve as electron donors in coordination with the immobilized chelates of some transition metal ions$(Ni^{2+})$.

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Antimicrobial Activity of Zirconium Pyrithione Complex (Zirconium Pyrithione 착물의 항균력)

  • Kwon, Chung-Moo;Rhee, Gye-Ju
    • Journal of Pharmaceutical Investigation
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    • v.18 no.3
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    • pp.107-111
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    • 1988
  • Zr, Cu, Zn and Fe-pyrithione complexes were prepared in aqueous medium and their antimicrobial activities were evaluated by MIC and cylinder plate methods against Bacillus subtilis, Sarcina lutea, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Trichophyton mentagrophytes, Candida albicans, Asperillus niger and Saccharomyces cerevisiae. Zr-pyrithione possessed most potent activities among the metal complexes against a wide range of microorganisms, especially Gram positive, B. subtilis, S. aureus and fungus, C. albicans. And all of the metal complexes synthesized were more active than pyrithione base. Fe(III)-pyrithione complex has an equal potency to Zn-pyrithione in general but it showed potent activity against B. subtilis microorganism than Zn-pyrithione.

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Hepatocellular carcinomas: correlation of enhancement degree with pathologic grades triple contrast MR imaging

  • Kim, Joo-Hee;Kim, Myeong-Jin;Park, Young-Nyun;Kim, Kyung-Sik;Lee, Woo-Jung
    • Proceedings of the KSMRM Conference
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    • 2001.11a
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    • pp.108-108
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    • 2001
  • Purpose: To correlate the histological differentiation of hepatocellular carcinomas (HCCs) with finding on triple contrast-enhanced MR imaging using gadolinium-chelates, superparamganetic ire oxides (SPIO), and mangafodipir trisodium. Method: Ten patients with proven HCC underwent triple contrast-enhanced MRI befo surgical resection. Subjective ratings of the enhancement pattern and degree were compare with the histological grades determined on surgical specimen. Quantitative measurements signal-to-noise ratio (S/N) of the lesion and the lesion-to-liver contrast-to-noise ratio C/N on the enhanced MR images, and the degree of S/N and C/N changes between the unenhanced and enhanced images were also correlated with the histological grades.

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MR Contrast Agents and Molecular Imaging (MR조영제와 분자영상)

  • Moon, Woo-Kyung
    • The Korean Journal of Nuclear Medicine
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    • v.38 no.2
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    • pp.205-208
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    • 2004
  • The two major classes of magnetic resonance (MR) contrast agents are paramagnetic contrast agents, usually based on chelates of gadolinium generating T1 positive signal enhancement, and super-paramagnetic contrast agents that use mono- or polycrystalline iron oxide to generate strong T2 negative contrast in MR images. These paramagnetic or super-paramagnetic complexes are used to develop new contrast agents that can target the specific molecular marker of the cells or tan be activated to report on the physiological status or metabolic activity of biological systems. In molecular imaging science, MR imaging has emerged as a leading technique because it provides high-resolution three-dimension maps of the living subject. The future of molecular MR imaging is promising as advancements in hardware, contrast agents, and image acquisition methods coalesce to bring high resolution in vivo imaging to the biochemical sciences and to patient care.

Synthesis of New 2-Quinazolylacetonitrile Derivatives (새로운 2-Quinazolylacetonitrile 유도체들의 합성)

  • Kim, Jung Hwan;Min, Kyung Su
    • Journal of the Korean Chemical Society
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    • v.45 no.6
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    • pp.532-537
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    • 2001
  • 2-Quinazolylacetonitrile derivatives containing H-chelate have been synthesized from 2-cyanomethylquinazoline using electrophiles such as 4-chloroquinazoline, 4-chloro-2-phenylquinazoline, 4,6-dichloropyrimidine, 4,6-dichloro-2-phenylpyrimidine, 4,6-dichloro-5-phenylpyrimidine, 2-chloroquinoxaline, 1,3-dichloroisoquinoline, 2,6-dichloropyrazine, 2-chloropyrazine and 4,6-dichloro-2,5-diphenylpyrimidine. These H-chelates may serve as a polymethine chromophore system. Structures of the target molecules were identified by spectral methods.

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The Synthesis of Pyrimidine Derivatives Containing H-Chelate (H-킬레이트가 있는 피리미딘 유도체들의 합성)

  • Kim, Jeong Hwan;Seo, Jeong Hyeop
    • Journal of the Korean Chemical Society
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    • v.34 no.6
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    • pp.637-640
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    • 1990
  • Bis (4,6-dichloropyrimidine-5-yl) alkanes as the frame of "intramolecular electronic energy transfer" system have been synthesized and the H-chelates of $\alpha$-(4-cyanomethylquinoline-6-chloropyrimidine-5-yl)-$\omega$-(4,6-dichloropyrimidine-5-yl) alkanes have been synthesized from bis (4,6-dichloropyrimidine-5-yl) alkanes and 2-cyanomethylquinoline. The structures of the compounds have been studied by spectral methods.

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Recycling of chelating agents after extraction of heavy metals contaminated in soil

  • Jung, Oh-Jin
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.10 no.S_3
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    • pp.139-148
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    • 2001
  • Heavy metals such as Cu, Ni, Cd, and Pb were chemically extract from the contaminated soils using the chelating agents, EDTA and DTPA. These chemical extraction have been focused on its applicability to a wide range of soils. Results of extractive efficiency for heavy metal follow the order : Cu-EDTA $\geq$ Ni-EDTA > Pb-EDTA > Cd-EDTA > Cu-DTPA> Pb-DTPA. This result is coincided with order of conditional formation constants(Kr) of metal-chelate agent. The second study involved the recovery of the metals and EDTA from complex solutions by an electromembrane process. The overall processes of regeneration, recovery, and reuse were evaluated. The electrochemical studies showed that copper could be chosen as an electrode to plate Cd, Cu, and Pb. At least 95% of 75 of EDTA and associated Cu or Pb could be recovered by the electromembrane process. Recovery of Cd by electodeposition was not possible with the copper electrode. The percent EDTA recovery is equal to the percentage of metal electroplated from the chelates.

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Synthesis, Characterization and Spectrophotometric Studies of Seven Novel Antibacterial Hydrophilic Iron(II) Schiff Base Amino Acid Complexes

  • Shaker, Ali M.;Nassr, Lobna A.E.;Adam, Mohamed S.S.;Mohamed, Ibrahim M.A.
    • Journal of the Korean Chemical Society
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    • v.57 no.5
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    • pp.560-567
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    • 2013
  • A series of new Iron(II) Schiff base amino acid complexes derived from the condensation of amino acid and sodium 2-hydroxybenzaldehyde-5-sulfonate have been synthesized. The complexes were characterized by elemental, electronic, IR spectral analyses and conductance measurements. The stability and solubility of the prepared complexes were determined. Two spectral methods used to determine the stoichiometry of the prepared complexes which exhibited divalent tridentate coordination and formed chelates of octahedral structures. The antibacterial activity of the prepared complexes has been tested against Bacillus cereus, Pseudomonas aeruginosa and Micrococcus bacteria. The effect of HCl on investigated complexes studied spectrophotometrically.