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        검색결과 130

        121.
        2005.09 KCI 등재 서비스 종료(열람 제한)
        A three-dimensional ecological model (EMT-3D) was applied to Nonylphenol in Tokyo Bay. EMT-3D was calibrated with data obtained in the study area. The simulated results of dissolved Nonylphenol were in good agreement with the observed values, with a correlation coefficient(R) of 0.7707 and a coefficient of determination (R2) of 0.5940. The results of sensitivity analysis showed that biodegradation rate and bioconcentration factor are most important factors for dissolved Nonylphenol and Nonylphenol in phytoplankton, respectively. In the case of Nonylphenol in particulate organic carbon, biodegradation rate and partition coefficient were important factors. Therefore, the parameters must be carefully considered in the modeling. The mass balance results showed that standing stocks of Nonylphenol in water, in particulate organic carbon and in phytoplankton are 8.60×105 g, 2.19×102 g and 3.78×100 g, respectively. With respect to the flux of dissolved Nonylphenol, biodegradation in the water column, effluent to the open sea and partition to particulate organic carbon were 6.02×103 g/day, 6.02×102 g/day and 1.02×101 g/ day, respectively.
        122.
        2004.06 KCI 등재 서비스 종료(열람 제한)
        The feasibility and efficiency of the hydrogen peroxide produced by an electrolysis cell reactor was investigated. From regulating voltages for the given reaction time, the concentration of the hydrogen peroxide was gradually increased with increasing voltages. Optimal voltage range was found to be 10~15 V. The concentration of hydrogen peroxide was much higher with oxygen gas than without oxygen gas in the cathodic chamber. But there was a little difference in the generating rate of hydrogen peroxide regardless of the presence of nitrogen gas. Under given conditions, the maximum value of ICE(Instantaneous Current Efficiency) was about 38%, and then current density was 74 mA/cm2. The specific energy consumption was 0.694[㎾h/kg-H2O2]. Since Esp (Specific Energy Consumption)was very little value, It did not demand high energy in this system. Using the hydrogen peroxide gained in the experiment, Fenton's reaction was conducted and the removal of nitrobenzene, 3-chlorophenol and dye wastewater was studied. This results were very similar to the Fenton's reaction by using commercial hydrogen peroxide.
        123.
        2003.01 KCI 등재 서비스 종료(열람 제한)
        The interaction of mastoparan B, a cationic tetradecapeptide amide isolated from the hornet Vespa basalis, with phospholipid bilayers was studied with synthetic mastoparan B and its analogue with Ala instead of hydrophobic 12th amino acid residue in mastoparan B. MP-B and its derivative, [12-Ala]MP-B were synthesized by the solid-phase peptide synthesis method. MP-B and its analogue, [12-Ala]MP-B adopted an unordered structure in buffer solution. In the presence of neutral and acidic liposomes, the peptides took an α-helical structure. The two peptides interacted with neutral and acidic lipid bilayers. These results indicated that the hydrophobic face in the amphipathic α-helix of MP-B critically affected the biological activity and helical content.
        124.
        1999.06 KCI 등재 서비스 종료(열람 제한)
        Among various reactions which metal sulfides can undergo in the reducing environment, the lattice exchange reaction was examined in a attempt to selectively remove heavy metal ions contained in the Fe-Coagulants acid solution. We have examined Zeta potential along with pHs to investigate surface characteristics of FeS(s). As a result of this experiment, zero point charge(ZPC) of FeS is pH 7 and zeta potential which resulted from solid solution reaction between Pb(Ⅱ) and FeS(s) is similar to that of PbS(s). Solubility characteristics of FeS(s) is appeared to that dissolved Fe(Ⅱ) concentration increased in less than pH 4, and also increased with increasing heavy metal concentration. Various heavy metal ions(Pb(Ⅱ), Cu(Ⅱ), Zn(Ⅱ)) contained in Fe-coagulants acid solution were removed selectively more than ninety-five percent in the rang of pH 2.5∼10 by FeS(s). From the above experiments, therefore, We could know that the products of reaction between heavy metal ions and FeS(s) are mental sulfide such as PbS(s), CuS(s) and ZnS(s).
        125.
        1998.08 KCI 등재 서비스 종료(열람 제한)
        This study estimate the degree of contamination in the streamwater around the Sudokwon landfill site. It was sampled at 10 sites in Jan., Apr., Jul. and Oct., 1996. There were analyzed five kinds of toxic chemical material-CN, ABS, PCB, As, Org-P, and four kinds of heavy metal-Pb, Hg, Cd, C_r^+6. The result are 1)The COD was generally increased to compare before landfill, 2)The Org-P and PCB were not detected at all points, 3)The concentrations of Pb, C_r^+6 and As were lower than the environmental criteria values, 4)The CN, Hg and Cd were over envirommental criteria values, and so emergent regulation is needed, 5)The effects of the streamwater contamination were not only the leachate of the landfill, but also the small factories and agricultural land around the landfill.
        126.
        1997.04 KCI 등재 서비스 종료(열람 제한)
        Toxic peptides from hornet venom, mastoparan and mastoparan-B were synthesized using the solid phase peptide synthesis method and investigated the interaction of them with phospholipid bilayer, antibacterial activity, and hemolytic activity. Both toxic peptides could induce dye release at a low concentration in neutral liposome. The binding affinity of mastoparan-B for neutral liposome was smaller than that for acidic one. Mastoparan and mastoparan-B had strong antibacterial activity for gram-positive bacteria, but weak or potent activity for gram-negative ones, respectively. Mastoparan and mastoparan-B lysed erythrocyte very little up to 5 μM.
        127.
        1997.02 KCI 등재 서비스 종료(열람 제한)
        Endotoxin from the cell wall of marine V. vulnificus was extracted using the hot phenol-water method, injected endotoxin into rat, and tested the toxic effect of endotoxin on the blood component in rat blood. The results showed that blood glucose, blood urea nitrogen, white blood cell, and reticulocyte were increased and red blood cell was the same as the number of control group(normal blood), but platelet was decreased. Above results suggested that endotoxin induced a malfunction of liver and that the increase of white blood cell was for the removal of foreign toxic substance.
        128.
        1996.10 KCI 등재 서비스 종료(열람 제한)
        The toxic substances (endotoxins) from the bacterial cell walls were extracted by using incubator, centrifuge, UV-Vis spectrophotometer, and their fatty acid compositions were analyze by Gas Chromatography. The lethal toxicities and pyrogenic activities of toxic substances were tested and the results were compared each other. The results of fatty acid analyses showed that the major fatty acid of the toxic substance was tetradecanoic acid for Vibrio vulnificus, dodecanoic acid for Escherichia coli and decanoic acid for Salmonella typhimurium. These three fatty acids were the main fatty acids for three toxic substances (more than 70%). The unique points in the fatty acid compositions were that tetradecanoic acid was composed as important one (37.15%) for V. vulnificus and that the amount of hexadecanoic acid was very small (below 2%) for three toxic substances. The lethal toxicity in ICR mice of toxic substance from V. vulnificus (LD_50 was 52.5 ㎎/㎏) was similar to that of E. coli (56.5 ㎎/㎏), but weaker than that of S. typhimurium (37.5 ㎎/㎏). Toxic substance from V. vulnificus was more pyrogenic in rabbit than that from E. coli, but less than that from S. typhimurium.
        129.
        1992.12 KCI 등재 서비스 종료(열람 제한)
        Physiological toxic and mutagenic effects of gramoxone in Drosophila melanogaster were invetigated. Gramoxone was highly toxic on the development, resulting in of lowering the viability and in prolongation of the developmental times. Adults treated with gramoxone during the developmental stages caused a lowering of the productivity and a little change in protein quantity. But the effect on the sex-linked lethal mutagenesis was found to be negative. The order of mortality causing adult stage feeding to gramoxone in the D. melanogaster complex was like this ; D. mauritiana, D. sechellia, D. simulans and D. melanogaster. Two species of the D. yakuba complex were alike. Those results were more or less correlation with speciation of the D. melanogaster subgroup.
        130.
        1992.07 KCI 등재 서비스 종료(열람 제한)
        The inhibitory effects of mercury ions on the growth of barley seedlings were studied and the distribution of metal elements in the organs of treated plants was investigated by using synchrotron radiation induced X-ray emission (SRIXE). Although the treatment of mercury ions caused growth inhibition, the mercury-specific increase in variable fluorescence and the abolishment of energy-dependent quenching in broken barley chloroplasts as shown by Moon et al. (1992) were not observed in the leaves of growth-inhibited seedlings. Instead the treatment of mercury decreased Fmax and Fo values. However, Fmax/Fo ratio and photochemical and nonphotochemical quenching coefficients were not affected significantly. By SRIXE analysis of 10μM mercury chloride treated seedlings, accumulation of mercury in roots was observed after 1 hour of treatment and similar concentration was sustained for 48 hours. Relative contents of mercury was high in roots and underground nodes where seeds were attached, but was very low in leaves. Iron and zinc were also distributed mainly in the lower parts of the seedlings. However after 72 hours of treatment the contents of these metals in roots decreased and their distribution became more uniform, which may lead to death of the plants. These results suggest that the observed inhibitory effects on barley seedlings upto 48 hours after the treatment is not due to direct damages in the photosynthetic apparatus, but due to its accumulation in roots and the consequent retardation of the growth of barley seedlings. The decrease in Fmax and Fo is probably due to the decrease in chlorophyll and protein contents caused by the retardation of growth. The observed slow expansion of primary leaves could be also explained by the retardation of growth, but the fluorescence induction pattern from the leaves did not show characteristic symptoms of leaves under water stress.
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