• Environmental Mutagens and Carcinogens
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• v.25 no.1
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• pp.6-12
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• 2005

Many compounds might become activated after absorption of UV light energy. In some cases, the resulting molecule may undergo further biological reaction of toxicological relevance related especially to the photo-carcinogenicity resulting from photo-genotoxicity. However, no regulatory requirements have been issued with the exception of guideline issued by the Scientific Committee of Cosmetology, Commission of the European Communities (SCC/EEC) on the testing of sunscreens for their photo-genotoxicity. Thus, the objectives of this study are to investigate the utility of photo-Ames assay for detecting photo-mutagens, and to evaluate its ability to predict rodent photo-carcinogenicity. Photo-Ames assay was performed on five test substances that demonstrated positive results in photo-carcinogenicity tests: 8-methoxypsoralen (photoactive substance that forms DNA adducts in the presence of ultraviolet A irradiation), chlorpromazine (an aliphatic phenothiazine an a-adr-energic blocking agent), lomefloxacin (an antibiotic in a class of drugs called fluoroquinolones), anthracene (a tricyclic aromatic hydrocarbon a basic substance for production of anthraquinone, dyes, pigments, insecticides, wood preservatives and coating materials) and retinoic acid (a retinoid compound closely related to vitamin A). Out of 5 test substances, 3 showed a positive outcome in photo-Ames assay. With this limited data set, an investigation into the predictive value of this photo-Ames test for determining the photo-carcinogenicity showed that photo-Ames assay has relatively low sensitivity (the ability of a test to predict carcinogenicity). Thus, to determine the use of in vitro genotoxicity tests for prediction of carcinogenicity,' several standard photo-genotoxicity assays should be compared for their suitability in detecting photo-genotoxic compounds.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.421-421
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• 2010

적색과 녹색 유기발광소자 보다 청색 유기발광소자는 상대적으로 발광 효율이 낮고 색 순도가 낮으며 수명이 짧은 이유로 유기발광소자를 이용한 전색 디스플레이 패널 구현에 많은 어려움이 있다. 이 문제를 해결하기 위하여 청색 유기발광 소자의 발광 효율을 향상하기 위한 방법으로 기존의 제작되는 불순물이 첨가된 단일 발광 호스트층을 이용한 유기발광소자와는 다르게 불순물이 첨가된 혼합된 발광 호스트층으로 구성된 발광 기능층을 가진 유기발광소자의 전기적 성질과 광학적 성질에 대한 연구를 하였다. 본 연구에서는 1.3-Bis(carbazol-9-yl)benzene 인광 호스트 유기화합물과 5%의 3-Tert-butyl-9,10-di(naphtha-2-yl)anthracene 형광 호스트 유기화합물을 혼합된 발광 기능층으로 적용하고 8%의 bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl-l) iridiumIII 인광 불순물을 첨가한 청색 유기발광소자와 5%의 4,4'-Bis[4-(diphenylamino)styryl] biphenyl (BDAVBi) 형광 불순물을 첨가한 청색 유기발광소자를 제작하여 전기적 성질과 광학적 성질을 비교하였다. 형광 불순물인 BDAVBi를 첨가하여 제작된 청색 유기발광소자는 전류밀도 $20\;mA/cm^2$에서 5.78 cd/A의 발광 효율을 구현하였다. 대역폭이 큰 인광 호스트 물질에서 형성된 엑시톤이 효율적으로 대역폭이 상대적으로 작은 형광 호스트로의 에너지 전달이 일어나고 형광 호스트에서 형성된 엑시톤이 대역폭이 더 작은 형광 불순물로의 에너지 전달이 효율적으로 전달 됨을 알 수 있다. 인광 호스트에서 형성된 엑시톤이 중간 과정을 거치지 않고 바로 형광 불순물로의 에너지 전달이 형성되어 주입된 캐리어가 기존의 소자보다 에너지 전달 과정을 거쳐 다수의 엑시톤이 소멸하지 않고 발광에 기여하여 상대적으로 전류가 작게 흐르고 다량의 엑시톤이 외부로 추출되어 효율이 증가하였다. 전계 발광 스펙트럼 분석에서 메인 피크가 467 nm 영역에서 형성되지만 불순물에 의한 부 피크가 491 nm 영역에서 형성되어 시각계 곡선과 중첩되는 영역을 추가로 형성하여 효율이 증가하게 되는 것을 알 수 있었다. 그러므로 불순물이 첨가된 혼합된 호스트 발광층을 적용한 유기발광소자는 높은 발광 효율을 가지는 청색 유기발 광소자 디스플레이 패널 제작 가능성을 제공하고 있다.

• Journal of Microbiology
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• v.43 no.4
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• pp.319-324
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• 2005

Estuarine sediments are frequently polluted with hydrocarbons from fuel spills and industrial wastes. Polycyclic aromatic hydrocarbons (PAHs) are components of these contaminants that tend to accumulate in the sediment due to their low aqueous solubility, low volatility, and high affinity for particulate matter. The toxic, recalcitrant, mutagenic, and carcinogenic nature of these compounds may require aggressive treatment to remediate polluted sites effectively. In petroleum-contaminated sediments near a petrochemical industry in Gwangyang Bay, Korea, in situ PAH concentrations ranged from 10 to 2,900 ${\mu}g/kg$ dry sediment. To enhance the biodegradation rate of PAHs under anaerobic conditions, sediment samples were amended with biostimulating agents alone or in combination: nitrogen and phosphorus in the form of slow-release fertilizer (SRF), lactate, yeast extract (YE), and Tween 80. When added to the sediment individually, all tested agents enhanced the degradation of PAHs, including naphthalene, acenaphthene, anthracene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, and benzo [a] pyrene. Moreover, the combination of SRF, Tween 80, and lactate increased the PAH degradation rate 1.2-8.2 times above that of untreated sediment (0.01-10 ${\mu}g$ PAH/ kg dry sediment/day). Our results indicated that in situ contaminant PAHs in anoxic sediment, including high molecular weight PAHs, were degraded biologically and that the addition of stimulators increased the biodegradation potential of the intrinsic microbial populations. Our results will contribute to the development of new strategies for in situ treatment of PAH-contaminated anoxic sediments.

• Journal of Life Science
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• v.18 no.4
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• pp.503-508
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• 2008

Deep sea water from the East sea was tested for breast cancer chemoprevention and metastasis by measuring the activities of cytochrome P450 1A1 and aromatase, invasiveness, and activity and expression of matrix metalloproteinase (MMP)-9 in breast MDA-MB-231 cancer cell. The in vitro incubation of rat liver microsome with deep sea water (a hardness range of $100{\sim}1,000$) showed a hardness-dependent inhibition of 7,12-dimethylbenz[a]anthracene (DMBA)-induced cytochrome P450 1A1 activity. Deep sea water showed 27.1, 45.4 and 51.9% inhibition of microsomal aromatase activity at the hardness of 600, 800 and 1,000, respectively. In addition deep sea water inhibited not only the invasiveness of 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated MDA-MB-231 cells through matrigel-coated membrane in a hardness-dependent manner but also the activity and expression of MMP-9 in MDA-MB-231 cell.

• Food Science and Biotechnology
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• v.27 no.6
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• pp.1843-1856
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• 2018

Tea is one of the most frequently consumed drinks due to its favourite taste and the health benefit. Tea is produced by several processes and drying is very important step to develop the flavour and destroys the enzymes in tea. However, during drying tea, polycyclic aromatic hydrocarbons some of which are carcinogen and genotoxin are naturally produced. The risk of PAHs by drinking tea was characterized by determining contents of 4 PAHs in tea. 4 PAHs including Benz(a)anthracene (BaA), Chrysene (CHR), Benzo(b)fluoranthene (BbF) and Benzo(a)pyrene (BaP) were investigated by GC-MS in total 468 tea products, which were contaminated up to $4.63ng\;g^{-1}$. Mate tea was the most highly contaminated by BaA, CHR, BbF and BaP and followed by Solomon's seal and Chrysanthemum. The Margin of Exposures calculated by the concentration of BaA, CHR, BbF and BaP and consumption amount of tea were higher than 10,000, and the risk of PAHs in tea were low concern to public health.

• Journal of Environmental Science International
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• v.27 no.11
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• pp.947-956
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• 2018

Trains have been a major means of transport in Korea during these past decades. However, train facilities such as stations and repair shops are contaminated with organic and inorganic substances. There is a high probability of train facility contamination with polyaromatic hydrocarbons (PAHs). This study evaluated the PAH and heavy metal contamination of soil near railroads in the Kyungpook area. A total of 18 soil samples were collected from the railroads and analyzed for 16 PAHs and 6 heavy metal species. The contamination level of the top soil was found to be slightly higher than that of the subsoil for contamination with PAHs. The ratio of carcinogenic PAH concentration to the total PAH concentration was relatively high, with a maximum of 0.9. The toxicity equivalent (TEQ) of the PAHs were 500.6 ng/kg in the topsoil and 355.5 ng/kg in the subsoil. The ratio of low molecular PAHs (LPAHs) to high molecular PAHs (LPAHs) ranged from 6.7 to 29.5; this shows that contamination is primarily due to combustion of fuel rather than due to petroleum. The ratio of phenanthrene to anthracene and the ratio of fluoranthene to pyrene also show that contamination occurred due to combustion for transportation. The heavy metal contamination level was lower than the Korean standard, but higher than the background concentration; this indicates that the soil was affected by the operation of the railways.

• Food Science of Animal Resources
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• v.43 no.5
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• pp.826-839
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• 2023

This study investigated the effects of different charcoals on the occurrence of 16 polycyclic aromatic hydrocarbons (PAHs) in grilled beef steaks and beef patties. Seven different charcoals were used as follows: from oak wood (C1), from orange wood (C2), from Valonia oak wood (C3), from Marabu wood (C4), extruded charcoal from beech wood (C5), from coconut shells (C6), and from hazelnut shells (C7). The grilling times for each charcoal type were 6 min for the beef patties and 7 min for the beef steaks, until the internal temperature reached at least 74℃. The total concentration of 16 PAHs (PAH16) in beef steaks grilled with C1 (35.75 ㎍/kg) and C7 (36.39 ㎍/kg) was higher than that of C3 (23.80 ㎍/kg) and C6 (24.48 ㎍/kg; p<0.05). The highest amounts of PAH16 (216.40 ㎍/kg) were determined in the beef patty samples grilled using C5 (p<0.05). The summation of benzo[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene, referred to as PAH4, was not detected in any of the beef steaks, whereas it was determined in the beef patties grilled with C2 (7.72 ㎍/kg) and C5 (22.95 ㎍/kg; p<0.05). The PAH16 concentrations of the beef patty samples in each charcoal group were significantly higher compared to the beef steaks (p<0.05). To avoid the formation of high PAH levels, the use of extruded charcoal and hazelnut shell charcoal should therefore be avoided when charcoal grilling beef steaks and beef patties, and low-fat meat products should be preferred.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.8
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• pp.574-582
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• 2012

This study presents the concentrations of the polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by United States Environmental Protection Agency (US EPA), in 98 sludges from 54 industrial wastewater treatment facilities of South Korea. The mean concentrations of ${\Sigma}_{16}PAHs$ were ranged from 32.5 ${\mu}g/kg-dw$ to 1189.3 ${\mu}g/kg-dw$ by industries, and the highest content was found in the petrochemical industry, followed by chemical, clothing manufacturing and dying, pulp and papermaking, secondary wastewater treatment, and food/beverage producing industries. Comparisons to the EU and Danish standards of ${\Sigma}_{16}PAHs$ in sewage sludge for land application showed only two samples (one from petrochemical, and the other from chemical industry) exceeded the limits. ANOVA test with PAH concentrations as variables revealed no statistically significant influences by industrial types and sampling time (i.e., seasonal variations). Pearson correlations between individual PAHs showed strong relationships (r>0.7) among 4-ring PAHs. Concentrations of acenaphthylene, anthracene, fluoranthene, benzo(a)anthracene, benzo(f)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene presented strong correlations to ${\Sigma}_{16}PAHs$. Principal component analysis discriminated entire samples into three groups by two principal components (PC1 and PC2) with 70% of data variations, in which industrial types were not of importance, but a dominance of certain PAHs. Samples in group-I, which is high PC1 and low PC2, were characterized by a dominance of 2-ring PAHs, and in group-II, PC1 and PC2 showed a linear relation, was dominant 4-ring PAHs. Group-III with low PC1 and high PC2 includes 17 samples showing a noticeably high contribution of 3-ring PAHs to ${\Sigma}_{16}PAHs$. This study provides concentrations of PAHs in industrial sludges collected from a wide variety of sources (six industrial types) and two seasons of sampling events, and the comparison of ${\Sigma}_{16}PAHs$ with other studies are also discussed.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.137-142
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• 2011

$TiO_2$-coated bamboo activated carbon has been prepared and utilized under UV irradiation as a pretreatment method for an effective biodegradation of the recalcitrant polyaromatic hydrocarbons (PAHs). The anatase $TiO_2$ was successfully coated on the bamboo activated carbon (AC) and it showed the highest photoactivity against methylene blue. In the absence of the PAHs-degrading bacteria PAHs having low molecular weight (i.e., naphthalene, acenaphthylene, acenaphthene, and fluorene) were degraded by 9.8, 76.2, 74.1, and 40.5%, respectively. Higher molecular weight PAHs, however, maintained high residual concentrations of PAHs (400-1,000 ${\mu}g$/L) after the same treatment. On the other hand, the overall concentrations of PAHs became lower than 340 ${\mu}g$/L when the pretreated PAHs were subjected to biodegradation by a PAH-degrading consortium for a week. Herein, phenanthrene, anthracene, fluoranthene, and pyrene were removed by 29.3, 61.4, 27.0, and 44.3%, respectively, indicating the facilitated potential biodegradation of PAHs. Activated carbon coated with $TiO_2$ appeared to inhibit growth of PAH degraders on the surface of AC, indicating planktonic degraders were dominantly involved in the PAH biodegradation in presence of the $TiO_2$-coated bamboo AC. It was proposed that an effective remediation technology for the recalcitrant PAHs could be developed when an optimum pretreatment process is further established.

• Korean Journal of Environmental Biology
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• v.22
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• pp.1-10
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• 2004

We conducted three experiments to estimate the toxicity of POPs (persistent organic pollutants) on two copepod species (Acartia erythraea and A. omorii) and Artemia sp.; (1) 48 h-LC$_{50}$ of A. omorii with the five PAHs [polycyelic aromatic hydrocarbons anthracene, benzo〔a〕pyrene, fluoranthene, phenanthrene, pyrene〕 which were often detected in the Gwangyang Bay, (2) toxicity of benzo〔a〕pyrene and TBT on Artemia in different temperatures (1$0^{\circ}C$, 15$^{\circ}C$, 2$0^{\circ}C$), (3) effects of benzo〔a〕pyrene and TBT on egg Production rate, hatching rate and fecal Pellet Production of two copepod species (A. erythraea and A. omorii) fed on Heterocapsa triquetra (dinoflagellate) exposed in benzo〔a〕pyrene. Toxic chemicals which were most effective to A. omorii were flueranthene (48 h-LC$_{50}$ 19.20 $\mu\textrm{g}$ L$^{-1}$ ) and benzo〔a〕pyrene (48 h-LC$_{50}$ 29.89 $\mu\textrm{g}$ L$^{-1}$ ). The toxi- city of chemicals to Artemia increased when temperature increased. The toxicity of TBT was about 100 times higher than that of benzo〔a〕pyrene at 15$^{\circ}C$. Food materials (Heterocapsa triquetra) exposed in benzo〔a〕pyrene, affected negatively the rate of egg production, hatching rate and the fecal pellet production of the copepods at the high concentration. It is suggested that an increase in the concentration of benzo〔a〕pyrene might offset the production of copepods in marine ecosystems. This study suggests that copepods may be used as n indicator for early warning of the risk of POPs in marine ecosystems.