• Title/Summary/Keyword: intermediates

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Gas phase Photocatalytic Oxidation of PCE with $TiO_2$ ($TiO_2$를 이용한 PCE의 기상 광산화처리)

  • 조인철;변종환;변은숙;이동근;김성우
    • Journal of Korean Society for Atmospheric Environment
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    • v.17 no.1
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    • pp.57-66
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    • 2001
  • Gas phase photocatalytic oxidation of tetrachloroethylene (PCE) under 370 nm ultra-violet irradiation was investigated with TiO$_2$ catalyst. During the photocatalytic oxidation of PCE vapor several kinds of intermediate were produced, and the reaction pathways were proposed on the basis of the production sequency of the intermediates. The intermediates in the pathways of PCE oxidation were hexachloroethane, pentachlotoethane, 1, 1, 2-trichloroethane, carbon tetrachl-oride, dichloroacetylchloride, chloroform, 1,1-dichloroethane, phosgene, CO, $CO_2$, HCl, Cl$_2$.

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Studies on Anti-Mcirobial and Anti-Cancer Functions of Polysaccharide Extracted from Ganoderma lucidum (영지버섯 다당체의 항미생물작용 및 항암작용에 관한 연구)

  • 김성환
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.27 no.6
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    • pp.1183-1188
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    • 1998
  • This study was carried out to elucidate the immunomodulating activity of protein bound polysac charide extracted from Ganoderma lucidum(PSG). Macrophage drived reactive radicals were known as an effector for antimicrobial and anticancer functions. The promising immune response molecule, reactive oxygen intermediates(ROIs), was determined in TIB 71 cells with PSG at various experimental conditions. Treatment with 0.5mg PSG significantly increased the production of ROIs, superoxide anion as well as hydrogen peroxide, from TIB 71 cells(p<0.001). Under the same concentration, con siderable results were obtained from 24 hour cultivation with 106 cells at 5% CO2 incubator. The cells were trigged with PMA(5.3 M) after primed BCG(100 M) or IFN (100U) alone could not induce the production of ROIs, but it had a significant potentiating effect on ROIs secretion when the cells were treated with PSG.

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The Effect of Trust Building Degree and Method in E-Commerce on Service Quality (전자상거래에서 신뢰의 구축 정도와 방법이 서비스 품질에 미치는 영향)

  • 서창적;전희준;김영택
    • Journal of Korean Society for Quality Management
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    • v.31 no.2
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    • pp.51-68
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    • 2003
  • This research addresses familiarity and degree of using Internet site and trust building to affect service quality in e-commerce. We assume that the familiarity and frequency of using Internet site affect perceived service quality of customer. Also it assumes that customer's trust building intermediates their relationships. Several hypotheses are set to test these assumptions empirically. Consequently, the results show that familiarity of using Internet site affects customer's perceived service quality significantly except for tangible. Also it is found that degree of customer's trust building intermediates the relationship between familiarity of using Internet site and customer's perceived service quality significantly. For gaining good trust of customer in Internet site, we suggest that familiarity should fit into customer's needs.

m-Phenylene-Linked Bis-(Biradicals). Generation, Characterization and Computational Studies

  • Nicolaides, Athanassios;Tomioka, Hideo
    • Journal of Photoscience
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    • v.10 no.1
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    • pp.165-173
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    • 2003
  • m-Phenylene-linked biscarbenes, bisnitrenes and carbenonitrenes can be formed photochemically from appropriate nitrogenous precursors. Generation of such reactive intermediates under matrix-isolation conditions allows for their characterization by spectroscopic techniques such as ESR, UV /vis and IR. The latter method is also useful in characterizing secondary products derived from these reactive intermediates. Computational chemistry methods complement experimental IR data, aiding, thus, in identification of such compounds. In addition electronic structure calculations help in developing qualitative and semi-quantitative models, which can be useful in predicting ground-state multiplicities. The parent systems of m-phenylene-linked carbenes and nitrenes have high-spin ground states, but a switching to lower multiplicity can be achieved by chemical substitution. The ground state and various low-lying excited states of m-phenylenecarbenonitrenes can be reasonably approximated by simple valence-bond depictions. Finally, m-phenylenecarbenonitrenes are photoreactive in the inert matrix isomerizing to cyclopropene derivatives.

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Could Organic Solvents Be Used for the Alteration of Flux of Hydrophobic Intermediates through a Metabolic Pathway in Microorganisms\ulcorner

  • Zucchi, Gioia;Khan, Jeffrey-A.;Vulfson, Evgeny-N.
    • Journal of Microbiology and Biotechnology
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    • v.8 no.6
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    • pp.719-722
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    • 1998
  • The addition of decane to biotransfonnation media containing Yarrowia lipolytica led to the accumulation of intennediate L-phenylacetaldehyde and L-phenethyl acetate during bioconversion of L-phenylalanine, whilst none of these products were obtained in conventional aqueous fennentations. The results obtained support an earlier hypothesis (Spinnler et al. 1996. Proc. Natl. A cad. Sci. USA 93: 3373-3376) that organic solvents, acting as "thermodynamic traps" for hydrophobic intermediates, can substantially alter metabolic fluxes.

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Analogue Substrate Cometabolism by Chemical Oxidation of Recalcitrant PAHs (난분해 PAHs의 화학적산화에 의한 유사기질동시대사)

  • 류선정;박갑성
    • Journal of Korea Soil Environment Society
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    • v.3 no.3
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    • pp.87-92
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    • 1998
  • The effect of chemically oxidized intermediates of Polynuclear Aromatic Hydrocarbon (PAH) compounds on the degradation of the parent PAHs was characterized and evaluated for the context of cooxidation. Anthracene and pyrene exhibited extensive degradation (mean percent removal of 57.5%) after 28 days of incubation by introducing the Fenton oxidation intermediate of the PAH compounds, while unoxidized anthracene and pyrene exhibited 12.5% removal The chemical oxidation products can serve as a structually similar analogue substrates for a consortia of soil microorganisms and as a metabolic intermediates in the biodegradation sequence of the parent PAH compounds. These results may be interpreted in the context of cooxidation mechanism whereby high recalcitrant PAH compounds are biodegraded in the soil and suggest a potential tool for bioremediation of PAHs contaminated soils and protection of groundwater.

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Degradation of 3-Chlorophenol by a Ultraviolet-Fenton Process: Parameters and Degradation Pathways (자외선 펜톤산화공정에 의한 수중 3-염화페놀 분해특성 및 분해경로 연구)

  • Kim, Il-Kyu
    • Journal of Environmental Science International
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    • v.22 no.9
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    • pp.1089-1095
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    • 2013
  • The degradation of 3-chlorophenol(3-CP) by various AOPs(Advanced Oxidation Processes) including the ultraviolet / hydrogen peroxide, the Fenton and the ultraviolet(UV)-Fenton process has been conducted. The highest removal efficiency for 3-CP in the aqueous phase was obtained by the UV-Fenton process among the AOPs. In the UV-Fenton process, The removal efficiency of 3-CP decreased with increasing pH in the range of 3 to 6, and it decreased with increasing initial concentration. As the intermediates of 3-CP by UV-Fenton reaction, 3-chlorocatechol, 4-chlorocatechol, and chlorohydroquinone were detected thus the degradation pathways were proposed.

Synthetic Approaches to Natural Antioxidant Benzastatin E, F and G Analogues

  • Le, Thanh Nguyen;Yang, Su-Hui;Khadka, Daulat Bikram;Cho, Suk-Hee;Zhao, Chao;Cho, Won-Jea
    • Bulletin of the Korean Chemical Society
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    • v.32 no.12
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    • pp.4309-4315
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    • 2011
  • For synthesis of benzastatin E, F and G analogues, the indole-2-carbaldehydes with or without substituents at C-5 position were prepared as key intermediates. Several synthetic attempts to achieve benzastatin E-G analogues were suggested using the indole-2-carbaldehyde intermediates.

Liquid-Phase Synthesis of Biaryl Compounds by the Hydrogenolysis of Pentaerythritol-Supported Biarylsulfonates

  • Kim, Chul-Bae;Lee, Sung-Kyung;Park, Kwang-Yong
    • Bulletin of the Korean Chemical Society
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    • v.31 no.9
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    • pp.2459-2466
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    • 2010
  • Unfunctionalized biaryl compounds were parallelly and combinatorially prepared by the traceless hydrogenolysis of biarylsulfonates supported on pentaerythritol. The hydrogenolysis using 2-propylmagnesium chloride in the presence of $dppfNiCl_2$ efficiently generated corresponding biaryl derivatives without any memory of the support. The strategy using pentaerythritol as a small soluble support was disclosed to have a potential to combine the benefits of both SPOS and solution-phase reaction with fast reaction rate, facile isolation of intermediates, easy analysis of intermediates and atom economical manner. The novel tetrapodal support is expected to be an efficient substitute for polymeric supports in many circumstances.

Factors Affecting Protein Adsorption at the Air-Water Interface (계면에서의 단백질 흡착에 끼치는 영향인자)

  • Song, Kyung-Bin
    • Korean Journal of Food Science and Technology
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    • v.25 no.5
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    • pp.521-525
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    • 1993
  • To elucidate adsorption of proteins and examine the molecular behavior of protein molecules at interfaces, various proteins at the air-water interface were studied. The adsorption data of bovine serum albumin intermediates indicated that the conformational state of a protein played an important role in adsorption of proteins at interfaces. The adsorption behavior of succinylated beta-lactoglobulin indicated that the increase in the net negative charge of the protein significantly inflenced both the kinetics and thermodynamics of adsorption. The adsorption kinetics of beta-casein showed that the salt that induced break-down of water structure decreased the rate of adsorption.

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