• Microbiology and Biotechnology Letters
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• v.7 no.3
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• pp.119-125
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• 1979

As the first step of domestic developmint of the nucleic acid-related compounds, purine base required auxotrophs from Brevibacterium ammoniagenes ATCC 6872 were derived by the ultraviolet irradiation or the treatment of N-methyl-N'-nitro-N-nitroso guanidine (NTG), diethyl sulfate (DES), and ethylme-thyl sulfate (EMS). The optimum conditions of mutation by means of several mutagens were induced respectively. The yield of mutants was 0.083％ by the ultraviolet irradiation, 0.67％ by the NTG treatment, 1.1％ by the DES treatment, and 0.45％ by the EMS treatment. Six strains among 239 auxotrophs were screened out to accumulate 5'-lMP in the culture broth. Cry-stalline 5'-lMP was isolated from the culture broth of Brevifbacterium ammoniagenes adnine-guanine less mutant D-21530 by the use of anion exchange resin, Amberlite IRA-402, and it was identified physically and chemically as 5'-inosinic acid.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.319-328
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• 1995

This study was carried out to investigate the resistance mechanism by three different kinds of procymidone-resistant and susceptible isolates of Botrytis cinerea which had been collected from green houses. The average resistance level of the resistant strains was 1,000 times higher than that of susceptible ones. Also, it was revealed that the resistance was not originated from components excreted by Botrytis cinerea, based on the result obtained from the treatment with piperonyl butoxide and triphenyl phosphate as an inhibitor of monooxygenase and esterase, respectively. The total lipod content of resistant strains was 1.3 times higher than that of susceptible ones, among fatty acids, palmitic acid, stearic acid, and linoleic and being 3.0, 2.5, and 2.0 times higher, respectinely. Also slight differences in sterol contents and components were observed. The crude chitin content was slightly higher in susceptible strains but contents of N-acetyl glucosamine, a hydrolysate of chitin, were about 2 times higher in resistant ones.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.639-646
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• 2007

This study performed several tests for the durability of the concrete coated with nano synthesis ceramics which do not contain volatile organic compounds harmful to environment. The tests were adhesion test on dry and humid concrete, SEM test, MIP analysis, carbonation, chloride diffusion by electronic facilitation, freezing-thawing resistance, alkaline resistance, and brine resistance test. In the adhesion test on dry and humid concrete, nano synthesis ceramics coating produced the highest results among all the coatings tested. Nano synthesis ceramics adhered solidly on the concrete surface. The adhesive strength seemed to result from the hydrogen bond between nano synthesis ceramics which are inorganic and generated by hydrolysis and re-condensation reaction and the concrete's hydrates such as calcium silicate aluminate or calcium silicate hydrate. SEM test and MIP analysis results show surface structure with finest crevices pore in the nano synthesis ceramics coating applied concretes. In the carbonation, chloride diffusion, and freezing-thawing resistance tests, the concretes with nano synthesis ceramics coating indicated the best results. Based on these test results, further progress in application of nano synthesis ceramics coatings to various concrete structures including costal structures and sewerage arrangements can be expected.

• Korean Journal of Environmental Agriculture
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• v.5 no.2
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• pp.85-94
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• 1986

To study fate of carbofuran in paddy system, C-14 labelled carbofuran was applied to paddy water containing rice seedlings and time course study was made on the distribution, metabolism and chemical transformation of the systemic insecticide. Carbofuran was readily absorbed by plant root and translocated to shoots where most of the radioactivities were confined to leaf tips. The fact that gradual increases in radioactivities of both aqueous phase extracts and non-extractable fractions of plants (shoots and root) increased with incubation is taken as an evidence that reactions (phase I and II) proceed in rice plants. Carbofuran and its five metabolites were all detected by TLC in organic phase extracts of paddy plants or soil. Evidence was put forward that carbofuran and its five metabolites were all identified as aglycones of conjugates. 7-benzofuranol and 3-hydroxycarbofuran were the most abundant aglycones. Soil microbes appears to have little effects on the metabolism of carbofuran. They increased radioactivity of non-extractable fraction and reduced that of organic phase extracts of paddy soil.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6196-6202
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• 2012

Oligo-alginate derivatives were extracted from brown algae and its antimicroalgal effects and reaction mechanism were investigated. Oligo-alginate derivatives were produced from sequential hydrolysis of high molecular weight alginate by treatment of 2 N HCl and 1% $H_2O_2$. Antimicroalgal activity of extracts was proportional to reaction time and activity was highest at 4 hrs. When oligo-alginate derivatives were treated to Akashiwo sanguinea and Cochlodinium polykrikoides, mobilities of cells were ceased. A. sanguinea cells were crushed and plasmolysis was induced in C. polykrikoides cells. To investigate the action mechanism of oligo-alginate derivatives, changes of intracellular (pHi) and extracellular pH (pHe) were determined in the microalgal cells exposed to 0.05% of oligo-alginate derivatives. pHi was decreased about 0.3 unit and pHe was increased about 0.9 unit. These results suggested that change of membrane potential by oligo-alginate derivatives could led to microalgal cell death.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.277-283
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• 2017

To produce sweet liquor without artificial sweeteners, 8 traditional rice pre-treatment methods (juk, beombeok, seolgitteok, gumeongtteok, mulsongpyeon, injeolmi, gaetteok, and godubap) were analyzed in this study. The formation of sugars with the help of ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase using nuruk as a substrate has been previously confirmed. During the early stages of the pre-treatment processes, the amount of maltose produced (in descending order of its concentration) by ${\alpha}$-amylase was observed to be as follows: gaetteok > seolgitteok > beombeok > mulsongpyeon > juk > injeolmi > gumeongtteok > godubap. However, changes in maltose concentrations with respect to the pre-treatment processes after 48 hours were observed to be as follows: injeolmi > beombeok = godubap > gumeongtteok > gaetteok = mulsongpyeon > seolgitteok > juk. Maltose produced using either ${\alpha}$-amylase or ${\beta}$-amylase showed similar results. Glucoamylase produced 10 mg/ml of glucose during the godubap process, which was the highest amount of glucose among all the methods. Moreover, when ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase were used concurrently, glucoamylase increased glucose production in the later stages. Therefore, the possibility of producing sweet liquor without employing artificial sweeteners was confirmed, even if the amount of sugar in the liquor varied with the pre-treatment process.

• The Korean Journal of Pesticide Science
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• v.9 no.2
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• pp.122-131
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• 2005

For development of new agrochemical fungicide, syntheses of pyrrolo[2,1-b]thiazole carboxanilide derivatives 9 and antifungal screening against 6 kinds of plant pathogens were carried out. Functionalization of carboxylic acid on C-2 into carboxanilide in the pyrrolo[2,1-b]thiazole resulted in new 20 candidates, in which are ${\alpha},{\beta}$-unsaturated carboxanilide and methyl groups that are in cis relationship. Treatment of acetoxy-1,4-thiazin with magnesium in refluxing methanol gave pyrrolo[2,1-b]thiazole ethyl ester 4 in higher yield than that of the previous report. Hydrolysis of this compound afforded the corresponding acid 5, which reacted with aniline derivatives in the presence of coupling reagent, DIC to give pyrrolo[2,1-b]thiazole carboxanilides 9. As the result of in vivo antifungal assay of 9 against rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, some compounds showed selectively antifungal activities against the rice blast and wheat leaf rust.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.121-131
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• 2014

Due to the high UV light scattering effect of Zinc oxide (ZnO), it is frequently used in sunscreen skincare products. Recently ZnO coated with silica has been used in cosmetics to improve UV protection, texture, decreased photocatalytic activity, dispersibility and stability of the skin care product. In this study, we developed a ZnO composite powder coated with silica for the future application to skincare products to block UV rays that could cause photoaging. To improve consumer's satisfaction rating, we used ZnO microparticles which are widely used in the cosmetics industry. The silica was coated using hydrothermal method with sodium silicate and acid hydrolysis. UV protection of the composite powder was analyzed by UV-Vis and in-vitro test and the advantages for practical use of this powder as a skincare product were determined.

• 한국생물공학회:학술대회논문집
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• 2004.07a
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• pp.21-33
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• 2004

In this study, Anaerobic sewage sludge in a batch reactor operating at $35^{\circ}C$ was used as the seed to investigate the effect of pretreatments of waste activated sludge and to evaluate its hydrogen production potential by anaerobic fermentation. Various pretreatments including physical, chemical and biological means were conducted to utilize for substrate. As a result, SCODcr of alkali and mechanical treatment was 15 and 12 times enhanced, compared with a supernatant of activated sludge. And SCODcr was 2 time increase after re-treatment with biological hydrolysis. Those were shown that sequential hybridized treatment of sludge by chemical & biological methods is most efficient process for sludge treatment. The pre-treatment activated sludge was tested to conform hydrogen production potential in batch experiments. When buffer solution was added to the activated sludge, hydrogen production potential increased as compare with no addition.

• Korean Journal of Environmental Agriculture
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• v.11 no.3
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• pp.215-223
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• 1992

A metabolic study has been conducted to investigate the conversion of pentachlorophenol(PCP) to water soluble metabolites in soybean and rice cell suspension cultures as well as in intact rice plants. PCP in plant cells was found to be exclusively transformed into water soluble metabolites. The relative rate of the metabolic conversion of PCP in decreasing order was soybean cultures > rice cultures > rice plants. Also observed was that, the older the cultures grown, the lower the conversion rate was. Primary water soluble metabolites isolated from both the 5 day old soybean and 8 day old rice cells were specifically hydrolyzed only by ${\beta}$-glucosidic linkage specific glucosidase, suggesting that the metabolites are ${\beta}$-glucose conjugates. The amount of glucose conjugates was increased with increasing time of incubation of PCP up to 24 hr in both soybean and rice cultures; Thereafter, it was decreased progressively. Most of the glucose conjugates were further metabolized to more polar conjugates in cells, but a portion of them was excreted into the culture medium.