• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.391-395
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• 1990

The kinetics of thermnal cis-trans isomerization reaction of 1-bromopropene(1-BP) was studied at temperatures from 620.8 to 753.15 K over the pressure range 0.17-50.3 Torr. Both the inhibition effect by cyclohexene or propene and the catalytic effect by HBr showed a radical process as the main mechanism of the isomerization. In the suppression of the radical process by the inhibitors, the molecular process also contributed to overall reaction rate. The reactions demonstrated the first order kinetics under both uninhibited and inhibited conditions and could be represented by the expressions (R = 1.987 cal/mol/K) $k_{un}/s^{-1} = (3.45{\pm}1.50){\times}10^{11}$exp$[(- 48100{\pm}2000)/RT]\;k_{ink}/s^{-1} = (2.98{\pm}1.40){\times}10^{12}$exp$[(- 55800{\pm}1800)/RT]$> where $k_{un}$ is the observed rate constant of cis-1-bromopropene(1-B$P_c$) to trans-1-bromopropene(1-B$P_t$) under uninhibited condition at initial pressure of 50 Torr and $k_{ink}$ is the rate constant under maximal inhibition by cyclohexene. The ratio of rate constants for bromine atom elimination from the allylic hydrogen of reactant(1-BP) and from the inhibitors, propene and cyclohexene, were measured from the observed rates of the uninhibited and inhibited reactions. The inhibition efficiencies of cyclohexene and propene were compared kinetically from the rate constants and shown to give good agreement with the previous results reported from other alkyl bromide pyrolyses.

• Environmental Analysis Health and Toxicology
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• v.16 no.4
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• pp.205-209
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• 2001

Lemna gibba was newly cultured and provided for toxicity tests. In this study, the chromate toxicity tests for Lemna gibba were performed according to the OECD Lemna growth inhibition test guideline. The test species was Lemna gibba, and the tests were repeated 5 times. To evaluate the toxicity test results, the average specific growth rate, EC50, 95％ confidential limit, and variances were calculated. The test performance was analyzed by the doubling time and test statistics. The average values of EC50 data determined by logistic and linear interpolation curves were 25.9 ppm and 35.4 ppm respectively (by chromate concentration). The doubling time of all controls were below 2.5 day, so all tests passed the criteria for the test performance. This study introduced a new test method, Lemna growth inhibition test, which is provided for the hazard assessment of aquatic environment.

• Journal of environmental and Sanitary engineering
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• v.16 no.3
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• pp.72-79
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• 2001

The selective catalytic oxidation of toxic aromatic solvents (benzene, toluene, ethylbenzene, and styrene) and their mixtures were studied on a $Pt/{\;}{\gamma}-Al_2O_3$ catalyst at temperature ranging from $160~350^{\circ}C$. The deep conversion of aromatic solvents was increased as the inlet concentration was decreased and the reaction temperature was increased. The reactivity increases in order benzene > toluene > ethylbenzene > styrene. In mixture, remarkable effects on reaction rate and selectivity have been evidence ; the strongest inhibition effect is shown by styrene and increase in a reverse order with respect to that of reactivity. The inhibition effect was increased in order styrene > ethylbenzene > toluzene > benzene. This trend is due to the competition adsorption between the two or three reactants on the oxidized catalyst. Also, the deep conversion change of benzene was a small in tertiary mixtures(including of benzene and styrene) comparing with conversion characteristics of binary mixture with styrene. This result was due to small concentration of styrene. which had very strong inhibition effect.

• Asian Journal of Turfgrass Science
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• v.8 no.1
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• pp.47-52
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• 1994

Attempts were made to investigate the antagonistic activity of soil borne microorganisms Pseudomonas spp. and Trichoderma spp. against to the pathogens of turf diseases Rhizoctionia solani spp. and Pythiom spp. in vitro by a dual culture bioassay. Inhibition zone between the edge of the my-celium and the margin of each antagonistic bacteria, Pocudontonas, on potato dextrose agar was measured 3 days after incubation at 28˚C. Psudomonas spp. showed relatively high inhibition of mycelium growth of R. solani AG-i and Pythium spp. which cause brown patch and pythium blight, respectively. Antagonistic fungi Trichodenma spp. also showed effective inhibition against mycelium growth of both pathogens, more proper methods of measuring the inhibition effects were required because of fast growth of Trichodenna hypae. Brown patch and pythium blight both, re-quire most higher rate of fungicide use to control in golf curses in Korea. Application of antagon-istic microorganisms are useful as biological resources an approach to sole environmental contamination.

• Journal of Environmental Science International
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• v.1 no.2
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• pp.145-155
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• 1992

The effect of various supplies of lead singly and in combination with aluminium on growth and chlorophyll biosynthesis was investigated in 7-day-old Vigna anguluris seedlings. Expose to 50 $\mu$N Pb or more drastically reduced root elongation rate. Significant depressions in root growth was observed within 1 day and no recovery of growth was seen over the duration of treatment period. Root elongation decreased depending on the Pb concentrations. Root growth inhibition was stronger than shoot growth inhibition. The initiation of lateral roots appeared to be more sensitive to Pb than the growth of main roots. Inhibition of root and shoot elongation by Pb was lessened by combined exposure of Pb and Al, suggesting that the presence of AA reverse the inhibitory effect of Pb alone. With the histochemical sodium rhodizonate method the rate of Pb uptake was dependent on the Pb concentration and exposure time of the roots to Pb salts. Pb was first deposited on the root surface and then translocated radially in the root cap cells. During a longer Pb administration (up to 72 h) Pb penetration was nonuniform, with accumulation within the cortex or endodermis. There was drastic reduction in chlorophyll content by Pb. The Pb inhibition of chlorophyll synthesis was concentration dependent. 5-Aminolevulinic acid dehydratase (ALAD) activity exhibited distinct inhibition from control. Reduction in chlorophyll content was accompanied by proportional changes in ALAD activity. Chlorophyll content and ALAD activity were less affected by combined exposure of Pb and Al, suggesting that Al has a protective effect against the inhibiting action of Pb on photosynthetic activity.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.2
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• pp.145-155
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• 1997

The effect of various supplies of lead singly and in combination with aluminium on growth and chlorophyll biosynthesis was investigated in 7-day-old Vigna angularis seedlings. Expose to 50 uM Pb or more drastically reduced root elongation rate. Significant depressions in root growth was observed within 1 day and no recovery of growth was seen over the duration of treatment period. Root elongation decreased depending on the Pb concentrations. Root growth inhibition was stronger than shoot growth inhibition. The initiation of lateral roots appeared to be more sensitive to Pb than the growth of main roots. Inhibition of root and shoot elongation by Pb was lessened by combined exposure of Pb and Al, suggesting that the presence of Al reverse the inhibitory effect of Pb alone. With the histochemical sodium rhodizonate method the rate of Pb uptake was dependent on the Pb concentration and exposure time of the roots to Pb salts. Pb was first deposited on the root surface and then translocated radially in the root cap cells. During a longer Pb administration (up to 72 h) Pb penetration was nonuniform, with accumulation within the cortex or endodermis. There was drastic reduction in chlorophyll content by Pb. The Pb inhibition of chlorophyll synthesis was concentration dependent. $\delta-Aminolevulinic$ acid dehydratase (ALAD) activity exhibited distinct inhibition from control. Reduction in chlorophyll content was accompanied by proportional changes in ALAD activity. Chlorophyll content and ALAD activity were less affected by combined exposure of Pb and Al, suggesting that Al has a protective effect against the inhibiting action of Pb on photosynthetic activity.

• KSBB Journal
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• v.8 no.4
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• pp.341-350
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• 1993

As an effort to develop an alternative transportation fuel, the production of methanol from methane gas was studied using the resting cells of an obligatory methanotroph, Methylosinus trichosporium OB3b. The reaction was carried out in high concentration phosphate buffer solutions with the flask-grown cells containing the exclusively cytoplasmic methane monooxygenase (sMMO) activity. The methanol accumulation rate was observed to be 79nmo1/mg·min during the initial 4.5hr. Phosphate-dependent inhibition was found for both sMMO and methanol dehydrogenase (MDH) activities, and the inhibition constants were 185mM and 42mM, respectively. The inhibition mode was noncompetitive. Methanol was found to be very inhibitory to the sMMO activity and the inhibition constant (noncompetitive) was 21mM when propylene was used as substrate. The sMO activity in the resting cells was declined very fast and the rate became very high during the methanol production. These results indicate that the use of M. trichosporium OB3b as a biocatalyst for the methanol production is heavily dependent on the stable maintenance of the whole-cell SMO activity as well as the effective alleviation of product inhibition.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.2
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• pp.89-107
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• 2012

Objectives: This study was performed to develop therapeutic prescription that is more significant than existing ones through extraction method and formulation changes. Methods: Yukmijihwangtang(YMJHT) was extracted in 80% ethanol, and their relative anti-oxidant activities as well as anti-inflammatory effects through immune modulation were measured. Results: Both water and ethanol extracted YMJHT showed does-dependent DPPH elimination activities. ROS inhibition activity was greater in water extracted YMJHT except for Moutan Cortex. NO inhibition assay results indicated that all groups showed higher NO inhibition activities in RAW 264.7 cells in dose dependent manner. Water extracted group showed higher NO inhibition activity than that of ethanol extracted group. TNF-${\alpha}$ secretion inhibition assay using RAW 264.7 cells, water extracted YMJHT showed higher activity than ethanol extracts. Growth rate of spleen cells was greater in all tested groups, with higher rate in YMJHT-EtOH than YMJHT-DW. Suppression of gene expression of IFN-r in spleen cells stimulated by Con A was higher in YMJHT-EtOH than YMJHT-DW. Suppression of gene expression of IL-10 in spleen cells stimulated by Con A was highest in YMJHT-DW with 40%. Suppression of gene expression of IL-4 in spleen cells stimulated by Con A were significant with 90% or higher in all groups and that of IL-12p35 were also higher than 90% in all cases. Conclusions: From the results, it shows that YMJHT has anti-inflammatory effects through immune modulation. However, the difference between YMJHT-EtOH and YMJHT-DW was not that significant. Further studies are needed to find out effective extraction methods of herbal medicine.

• The Korean Journal of Food And Nutrition
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• v.36 no.2
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• pp.114-121
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• 2023

The objective of this study is to evaluate the antioxidant components, elastase inhibition activities, and melanin synthesis rates of Korean traditional Actinidia (Actinidia arguta) fruits and leaves depending on the ethanol extraction concentrations. The total polyphenol content was the highest in the 50% ethanol extract of both fruits and leaves, with values of 634.1 mg GAE/100 g and 3,985.2 mg GAE/100 g, respectively. The total flavonoid content was the highest in the fruit 90% extract and leaf 50% extract at 191.9 mg/100 g and 2655.6 mg/100 g, respectively. The vitamin C content was the highest in the 50% extract of leaves at 2990.3 mg/100 g. Elastase inhibition was the highest at 56.9% in the leaf 50% extract at a concentration of 1,000 ㎍/mL. Melanin synthesis inhibition showed the highest melanin synthesis inhibitory effect among the extracts, as the leaf 50% extract showed an inhibitory rate of 65% or more. Therefore, the antioxidant components, elastase inhibition activities, and melanin synthesis inhibitory rate were better in leaves than in fruits. The leaf 50% extract was particularly the best among the extracts. Korean traditional Actinidia leaves can be considered as potential sources for new functional materials.

• Journal of environmental and Sanitary engineering
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• v.14 no.2
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• pp.25-31
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• 1999

Energy recovery technology from municipal solid waste has been increasingly established in many countries. Anaerobic treatment of municipal sewage sludge has low digestion efficiency because of low organic loading rate of sewage sludge. The purpose of this study was to evaluate anaerobic biodegradability of food waste which was based on organic loading rate and seeding rate. From the results of anaerbic biodegration, the optimum condition for seeding rate was turn out over 40%, which did not inhibition of methane production.