• 한국환경과학회지
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• 제14권3호
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• pp.327-333
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• 2005

The performance of ozone contactor in ozone-BAC advanced water treatment process was evaluated by the degree of decomposition of organic matters. The degree was measured by the analyses of $UV_{254}$ absorbance and the concentrations of DOC and BDOC for the sand filtered water and the ozone treated water, respectively. In addition, the ozone concentration in the contactor, required for the maximum BDOC concentration, was selected as the optimum concentration, and the appropriate residential time of ozone treated water in a reservoir was recommended based on the residual ozone concentration in the treated water. The following results were obtained from the pilot scale experiments. By ozonation $UV_{254}$ absorbance was decreased, and BDOC concentration was increased. The change of DOC concentration by ozonation was negligible, but the excess input of ozone resulted in the removal of the small amount of BDOC by complete oxidation. The optimum ozone concentration was 0.58mg $O_3/mg$ DOC. In order to remove residual ozone, 20minutes of the residential time were enough after ozonation.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제1권2호
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• pp.137-144
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• 1997

Flocculation-spectrophotometry and streaming current detector(SCD) method were investigated and compared in order to determine the optimum dosages of synthetic cationic polymers of different charge density and molecular mass for the removal of humic acid. The optimum dosage for each of the polymers was determined with the dosage at which the lowest absorbance of humic acid was shown for the former and was determined with the dosage required during charge neutralization of humic acid for the latter. It was in good agreement between both methods and there is a strong inverse correlation between the optimum dosage and charge density of the polymers, with highly charged polymer giving the lowest optimum dosage, pointing out the importance the charge neutralization. By flocculation-spectrophotometry, it was found that the absorbance of humic acid with the amount of each of the polymers dosed, changes sharply for polymers of high charge density, but changes rather broadly for polymers of low and middle charge density. Both methods showed that a stoichiometric correlation exists between the optimum dosage of each of the cationic polymers and the negatively charged humic acid.

• Preventive Nutrition and Food Science
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• 제21권4호
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• pp.355-360
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• 2016

The influence of extraction temperature, powder concentration, and extraction time on the antioxidant properties of aqueous ginger extract was investigated. The possibility of estimating the antioxidant properties of the extract from its absorbance and colour properties was also investigated. Results indicated that powder concentration was the most significant factor to consider in optimizing antioxidant extraction. However, temperature and time still influenced the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity while extraction temperature influenced the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the extract. Using the total phenol content, total flavonoid content, ABTS radical scavenging activity, and DPPH radical scavenging activity of the extract, the multiresponse optimization condition for extraction of antioxidant based on the experimental range studied is $96^{\circ}C$, 2.10 g/100 mL, and 90 min. The absorbance of the ginger extract at 610 nm could be exploited for rapid estimation of its total flavonoid and polyphenol with a $R^2$ of 0.713 and 0.753, respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제12권6호
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• pp.891-894
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• 1999

A field experiment was conducted with Calliandra calothyrsus of fifteen provenances to evaluate the variation in the condensed tannin content of fresh leaves. Plants were raised in a nursery for three months and planted in the field. Experimental design was line planting of double hedgerows (3 m long plot, 1/2 meter interval, 45 plants in each plot) with 5 replicates. Plants were lopped every 5 months and samples (10 different plants within a plot; 4 newly flushed leaves, 4 partially expanded leaves and 4 mature full expanded leaves from each of 10 trees in a plot) were collected and were put on ice before transfer to the laboratory. Proanthocyanidine was extracted in aqueous acetone, and total extractable proanthcyanidine (TEPA) and total proanthocyanidine (TOPA) were measured. In addition, proximate analyses were made of different provenances. Crude protein contents varied from 19.74% to 16.45%; in vitro organic matter digestibility ranged from 36.09% to 23.32%. TEPA content ranged from 11.22 to 16.01 (measured as absorbance at $550nm,\;g^{-1}$ DM) and TOPA from 24.57 to 31.72 (measured as absorbance at $550nm,\;g^{-1}$ DM) TEPA and TOPA had a positive correlation, whereas crude protein content of Calliandra was negatively correlated with TEPA and TOPA. Provenances, such as Georgesville (Belize), local, Coban (Guatemala), Patulul (Guatemala), Bombana (Mexico) can be selected on the basis of nutritive value of fodder.

• 복식
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• 제27권
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• pp.121-132
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• 1996

This study showed the proper pigment extract in the Phe. Dyeing which is the basic dye of the natural plants dyeing,. Also it compared and examined the K/S the promotion of the color fastness and the effect of color difference change were attended by mordants and method of mordanting. 1. The most absorbance of Phellodendron. sol-ution is 330nm berberine is 430nm. 2. The best and proper temperature to extrat Phe,. was 80 and dyeing solution for 24 hours. 3. The pH effect was stable in the absorbances and color differences change. 4. Mordanted group increased the absorbances compared to non-mordanted sample. In case depth the most absorbance of Al. Sn. K. Cu and C. A solution were in 3% Fe and Cr were in 5%. In the color difference change they became dark reduced greenish and increased yellowish when their absorbances were in 3% 5. K./S was recoginzed by tainnin and fe, K/S was more increased pre-mordants than post-mordants. 6. Fe is the unchangable mordant in the color difference change and pre-mordants is more stable than post-mordants in the difference color. 7. Generally light C. F indicated more than grade 2 and light C. F, was much improved in post-mordanted by alumium potassium potass-ium dichromate. Washing C.F was improved in mordanted by tainnin and ferrous suulfate mordanted group was better than non-mordanted sample. Perspir-ation C,F was more stable in acid than alkali. Dry cleaning C.F indicated more than grade. 4.

• Bulletin of the Korean Chemical Society
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• 제26권1호
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• pp.107-114
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• 2005

Molecular aggregates of surfactant molecules consisting of one or more bilayers arranged in a hollow, closed, usually spherical geometry are termed “esicles”or “iposomes” In recent years it has been found that in certain systems the vesicular structure forms spontaneously and is long lived, and it has been suggested that these structures may in fact constitute the equilibrium state in these cases (as is true of micelles) This paper deals with the mixed CMC, vesicles, phase behavior, phase transition, geometrical structure, their formation and characterization in the aqueous solutions of mixed cationic/anionic surfactants systems. TEM micrographs revealed that the vesicles were of spherical shape and that their size was of around 180 nm. The zeta potentials are positive at CGS1-rich regions and negative at SLES-rich regions. In the region where SLES/CGS1 (6/4), the zeta potentials are very small, implying that the vesicles at this surfactant ratio may be less stable. At other surfactant ratios, the vesicles are thought to be stable, supported by large absolute values of zeta potentials and little change in UV absorbance for several months.

• Asian-Australasian Journal of Animal Sciences
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• 제18권7호
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• pp.1041-1047
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• 2005

This study was carried out to investigate the changes of chemical and sensory properties and cholesterol lowering effect of milk treated with $\beta$-cyclodextrin to reduce cholesterol and supplemented with evening primrose oil (EPO). The average cholesterol removal rate was 93.5%. The thiobarbituric acid (TBA) absorbance increased proportionally to storage period and amount of EPO addition. TBA absorbance was significantly different in the EPO-added groups from that in unadded groups in all periods. The production of short-chain free fatty acids (FFA) increased with longer period of storage. From 6 days of storage, the amounts of short-chain FFA in 6 and 10% EPO-added groups were significantly different from other groups. The scores for all sensory characteristics indicated that sensory quality decreased with both storage time and increasing amount of EPO. Oxidative off-flavor and off-taste were more intense with higher amounts of EPO addition and longer storage period. Also, the higher the amount of EPO addition, the lower overall scores throughout the 15 day storage. Feeding 10% EPO-supplemented cholesterol-reduced milk increased high density lipoprotein (HDL) in male Sprague-Dawley rats by 76%, which is significantly different from the control (27%).

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1513-1520
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• 2010

A bacterium capable of producing melanin pigment in the presence of L-tyrosine was isolated from a crop field soil sample and identified as Klebsiella sp. GSK based on morphological, biochemical, and 16S rDNA sequencing. The polymerization of this pigment occurs outside the cell wall, which has a granular structure as melanin ghosts. Chemical characterization of the pigment particles showed then to be acid resistant, alkali soluble, and insoluble in most of the organic solvents and water. The pigment got bleached when subjected to the action of oxidants as well as reductants. This pigment was precipitated with $FeCl_3$, ammoniacal silver nitrate, and potassium ferricynide. The pigment showed high absorbance in the UV region and decreased absorbance when shifted towards the visible region. The melanin pigment was further charecterized by FT-IR and EPR spectroscopies. A key enzyme, 4-hydroxyphenylacetic acid hydroxylase, that catalyzes the formation of melanin pigment by hydroxylation of L-tyrosine was detected in this bacterium. Inhibition studies with specific inhibitors, kojic acid and KCN, proved that melanin is synthesized by the DOPA-melanin pathway.

• Natural Product Sciences
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• 제20권3호
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• pp.176-181
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• 2014

The antioxidant activities of 29 components isolated from the aerial parts of Artemisia iwayomogi were evaluated in vitro and in cell culture. Among the tested compounds, 2, 6, 8, 10, 13, and 14 exhibited the greatest peroxyl radical-scavenging activities in the oxygen radical absorbance capacity (ORAC) assay, and 2, 10, and 14 also showed significant reducing capacities. However, all compounds showed weak metal chelating activities. Their cellular antioxidant activities were evaluated in HepG2 cells. At $10{\mu}M$, compounds 6, 8, and 14 exhibited stronger protection against 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress than compounds 2, 10, and 13. Moreover, Compounds 2 and 8 were more effective in protecting against $Cu^{2+}$-induced oxidative stress than compounds 6, 10, 13, and 14 at $10{\mu}M$. These results suggest that the phenolic compounds in A. iwayomogi have the potential to be developed as natural antioxidants for the treatment of oxidative stress-related diseases.

• 환경위생공학
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• 제13권3호
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• pp.58-65
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• 1998

Monodispersed $SiO_2/ZnO$ composite fine powders were prepared by Sol-Gel processing and their surface electrical and UV absorbance properties were investigated. Pseudomorph ZnO fine powders were microcapsuled by $SiO_2/ZnO$ sol fabricated using TEOS[tetraethylorthosilicate, purity 98% and ethanol as a solvent with $NH_3$ catalyst. The effects of experimental parameters such as molar ratio of starting materials on the final particle size and shape of $SiO_2/ZnO$ composite fine powder were discussed. As a result, we could controlled the size of monodispersed $SiO_2/ZnO$ composite fine powders without agglomeration, as well as the good dispersibility in aquous solution. The prepared powders were observed to have the mean particle sizes of $0.26-0.78{\mu}m$ with standard deviations of $0.020-0.063{\mu}m$.