• 대한의생명과학회지
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• 제9권2호
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• pp.93-98
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• 2003

To investigate the cyclohexane and xylene mixture treatment on the liver damage, the rats were treated by the mixture of cyclohexane and xylene (CH＋X) and then, liver damage was demonstrated by liver function findings based on liver weight/body weight, serum level of alanine aminotransferase (ALT), xanthine oxidase (XO) and then compared with cyclohexane treated group (CH group) and xylene-treated group (X). The CH＋X group showed merely severer liver damge than CH or X group. On the other hand, CH＋X group showed lower activity of hepatic cytochrome P-450 dependent aniline hydroxylase (CYPdAH) than CH or X group, but no statical differences were demonstrated among three experimental groups. Especially the hepatic GSH content was merely declined than CH or X group and the activity of hepatic GST was higher in CH＋X group than CH or X group. In conclusion, cyclohexane and xylene mixture treated animals showed merely severer liver damage than cyclohexane or xylene treated group and such a fact may be caused by inhibition of cyclohexane or xylene metabolism and oxygen free radical.

• 대한환경공학회지
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• 제35권6호
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• pp.389-393
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• 2013

본 연구의 목적은 유류로 오염된 토양으로부터 분리된 고효율 분해균주에 의한 xylene 분해특성을 조사하고 분해과정을 밝히는 것이다. P. putida BJ10에 의해 mineral salts medium (MSM)배지내에서 24시간 배양 후 제거율은 o, m, p-xylene 각각 94, 90, 98%였으며 3% 이하의 대조군과 명확한 차이를 보였다. 또한 유류로 오염된 토양내에서의 9일 경과 후 xylene 제거율은 유류 분해균주 주입구에서 66%였으며 무처리 일반토양에서 32%, 멸균 토양에서 8%로서 P. putida BJ10에 의한 유효성을 확인할 수 있었다. 또한 시간경과에 따른 대사산물을 분석한 결과 o-xylene의 분해 경로에서는 6시간 경과 후 3-methylcatechol, 24시간 경과 후 o-toluic acid 가 분해산물로서 검출되어 최종산물로서의 o-toluic acid 가 확인되었으며 중간산물의 변환과정은 기존 발표된 연구들과 다소 다른 결과를 나타내었다.

• 한국환경보건학회지
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• 제27권2호
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• pp.10-16
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• 2001

To evaluate an effect of circadian variation on the xylene metabolizing enzyme activities, 50% m-xylene in olive oil(0.25 $m\ell$/100g body weight) was intraperitoneally administered to the rats every other day for 6 days both in the night; 24:00 and the day; 12:00. Then animals were sacrigiced at 8hr after last injection of m-xylene. Hepatic microsomal cytochrome p450 contents were more increased both in control and xylene treated rats of night phase than those of day phase. But the activity of hepatic alcohol dehydrogenase(ADH) in control of night phase showed the similar value with that in those of day phase and xylene treated rats of day phase showed an increasing tendency of hepatic ADH activity as those of night phase showing similar activity. Furthermore, control rats of night phase than those of day phase. And by xylene treatment, enzyme activities of rats of day phase were higher tendency in rats of control but those of night phase were somewhat inhibited. Besides, xylene-treated animals of night phase showed increasing tendency of urinary methylhippuric acid concentration compared with those of day phase. On the other hand, liver weight per body weight(%), hepatic lipid peroxide content and serum xanthine oxidase activity were higher in night phase. And the activities of hepatic oxygen free radical metabolizing enzymes such as xanthine oxidase, gluthathione S-transferase, and xylene-treated rats of night phase than those of day phase. In conclusion, it can be hypothesized on the basis of the results that the accumulation rate of m-xylene intermediate metabolite, i.e. m-methylbenzaldehyde in liver tissus may be higher in night phase than in day phase and it may be responsible for higher liver toxicity in bight phase than in day phase.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권6호
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• pp.38-47
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• 2013

This study was performed to identify the optimal operating conditions and to evaluate the xylene removal efficiency, applying in-situ soil flushing with the low concentrated solution of 'Tween 80' at the xylene contaminated site. The pilot scale test site ($5m{\times}5m{\times}3m$), was mainly composed of 'sandy loam', with the average hydraulic conductivity of $9.1{\times}10^{-4}cm\;s^{-1}$. The average xylene concentration of the site was 42.1 mg $kg^{-1}$, which was more than 2.5 times higher than Korea soil pollution warning limit (15 mg $kg^{-1}$). For the soil flushing, 7,800 L of 0.1~0.2% surfactant solution was injected into three injection wells at the average injection time of 9 hr $d^{-1}$ for 10 days, followed by the additional only groundwater injection of 6,000 L. The same amount of the effluent solution was extracted from three extraction wells. From the analysis for xylene concentration of all effluent at 3 extraction wells, total 166 g of xylene was removed by in-situ surfactant flushing. Even though the residual xylene concentrations of 7 soil sampling locations in the test site were different due to the soil heterogeneity, from the comparison of xylene concentration at 7 locations before/after the feasibility test, 53.9% of the initial xylene in the site was removed from three extraction wells (mainly Ext-N and Ext-M well). The results showed that the in-situ soil flushing by using low concentrated 'Tween 80' solution had a great potential to remediate the xylene contaminated site.

• 한국화재소방학회논문지
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• 제31권5호
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• pp.1-6
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• 2017

가연성물질의 화재 및 폭발 특성치는 안전한 취급, 저장, 수송, 처리 및 폐기하는데 반드시 필요하다. 공정 안전을 위한 대표적인 연소특성치로 최소자연발화온도(AIT)를 들 수 있다. 최소자연발화온도는 가연성 액체의 안전한 취급을 위해서 중요한 지표가 된다. 최소자연발화온도는 가연성물질이 주위의 열에 의해 스스로 발화하는 최저온도이다. 본 연구에서는 ASTM E659 장치를 이용하여 가연성 혼합물인 n-Pentanol과 p-Xylene 혼합물의 최소자연발화온도와 발화지연시간을 측정하였다. 2성분계를 구성하는 순수물질인 n-Pentanol과 p-Xylene의 최소자연발화온도는 각각 $285^{\circ}C$, $557^{\circ}C$로 측정되었다. 그리고 측정된 n-Pentanol과 p-Xylene 혼합물의 최소자연발화온도와 AIT에서의 발화지연시간의 실험값은 제시된 식에 의한 계산값과 적은 평균절대오차에서 일치하였다. 따라서 본 연구에서 제시한 예측식들을 이용하여 n-Pentanol과 p-Xylene 혼합물의 다른 조성에서도 최소자연발화온도와 발화지연시간을 예측이 가능하다.

• Journal of Microbiology and Biotechnology
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• 제4권1호
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• pp.63-67
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• 1994

A microorganism showing degradative activity towards benzene, toluene and ${\rho}-xylene$ (BTX) was isolated from an activated sewage sludge and was tentatively identified as Pseudomonas fluorescence BE103. This strain was found to utilize benzene and toluene as growth substrates, but to degrade ${\rho}-xylene$ in the obligate presence of a growth substrate. The metabolic product resulted from the cometabolism of ${\rho}-xylene$ was identified as 3, 6-dimethylpyrocatechol by LC/MS analysis, and the metabolic pathway was analyzed to be similar to the tod pathway. From the kinetic studies done regarding BTX biodegradation using Pseudomonas fluorescence BE103, it was revealed that the cometabolism of ${\rho}-xylene$ is significantly affected by the ratio of growth substrate concentration to biomass concentration, and that the cometabolism of ${\rho}-xylene$ initiates only when this ratio was about 0.03.

• Journal of Microbiology and Biotechnology
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• 제8권3호
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• pp.222-228
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• 1998

The characteristics of cometabolic removal of xylenes by Alcaligenes xylosoxidans Y234 were investigated. m-Xylene was found to be degraded while ο- and p-xylene were biotransformed into cresols in the presence of benzene or toluene. A lower level of benzene was required than that of toluene to remove the same amount of xylenes, which suggested benzene was a more effective primary substrate than toluene. ο-Xylene was found to be the most toxic to Alcaligenes xylosoxidans Y234 followed by p-xylene and m-xylene. Rates of cell decay during cometabolic removal of ο-, m-, or p-xylene were decreased by up to $76\%$ when benzene-adapted cells were inoculated. Xylenes were removed efficiently using benzene-adapted cells.

• Toxicological Research
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• 제33권3호
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• pp.233-238
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• 2017

Xylene is a cyclic hydrocarbon and an environmental pollutant. It is also used in medical technology, paints, dyes, polishes and in many industries as a solvent; therefore, an understanding of the interaction between xylene and human lymphocytes is of significant interest. Biochemical assessment was used to demonstrate that exposure of lymphocytes to xylene induces cytotoxicity (at 6 hr), generates intracellular reactive oxygen species, collapse of mitochondrial membrane potential, lysosomal injury, lipid peroxidation and depletion of glutathione (at 3 hr). The findings show that xylene triggers oxidative stress and organelle damage in lymphocytes. The results of our study suggest that the use of antioxidant, mitochondrial and lysosomal protective agents can be helpful for individuals subject to chronic exposure to xylene.

• 에너지공학
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• 제25권1호
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• pp.48-55
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• 2016

최소자연발화온도는 가연성물질이 주위의 열에 의해 스스로 발화하는 최저온도이다. 최소자연발화온도는 유기혼합물중 가연성 액체혼합물의 안전한 취급을 위해서 중요한 지표가 된다. 본 연구에서는 ASTM E659 장치를 이용하여 가연성 혼합물인 n-hexanol+p-xylene 계의 최소자연발화온도를 측정하였다. 2성분계를 구성하는 순수물질인 n-hexanol과 p-xylene의 최소자연발화온도는 각 각 $275^{\circ}C$, $557^{\circ}C$로 측정되었다. 그리고 측정된 n-hexanol+p-xylene 계의 최소자연발화온도는 제시된 식에 의한 예측값과 적은 평균절대오차에서 일치하였다.

• Bulletin of the Korean Chemical Society
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• 제23권1호
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• pp.59-64
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• 2002

A facile and precise batch oxidation reaction system allows continuous monitoring of the oxidation rate and cumulated oxygen conversion of xylenes, and the side reactions to carbon monoxide and carbon dioxide may also be studied. The oxidation reaction can be analyzed precisely with the rate and amount of oxygen consumed. The reaction reveals that 4-carboxybenzaldehyde is an unstable intermediate of p-xylene oxidation as the reaction proceeds instantaneously from p-toluic acid to TPA (terephthalic acid). The alkali metals accelerate oxidation, even though they retard the reaction initially. The oxidation rate increases with decreasing water concentration. However, in the later part of reaction, the reactivity decreases a bit if the water concentration is very low. This retarding effect of water can be overcome partly by the addition of potassium. The oxidation of o-xylene, compared with the oxidation of p-xylene and m-xylene, proceeds quite fast initially, however, the oxidation rate of xylene isomers in the later stage of reaction is in the order of p-xylene > mxylene > o-xylene.