• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.122-126
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• 1999

시스템 레벨 PCB(Printed Circuit Board) 디자인은 최종적인 시스템 특성에 정확한 정보를 갖지 못하는 디자인 결정을 하기 위해 여러 가지 정보가 필요하다. 또한 분할 할 때 분할 시간과 방법은 매우 중요하고 합성 결과의 특성은 교환(tradeoffs)과 디자인 결정에 매우 민감하다. 그러므로 만일 디자인이 합성되고 단일 보드로 디자인된다 할지라도 후에 다중 보드로 분할 될 수 있다. 따라서 본 논문에서는 PCB회로 디자인의 제약구동 방법중 off-critical-path 분할기법을 사용한 휴리스틱(heuristic) 방법을 제안했고 교환 그래프 착색 알고리즘을 제안했다.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2003.10a
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• pp.63-63
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• 2003

• Analytical Science and Technology
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• v.16 no.4
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• pp.309-319
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• 2003

This study was performed to describe analysis method of 209 PCB congeners in ambient air samples. The samples were collected by high volume air sampler in Chonju city. Extracted samples were cleaned by silicagel cleanup modified with sulfuric acid and activated carbon cleanup processing. The cleaned samples were analyzed by high resolution gas chromatography and high resolution mass spectrometry (HRGC/HRMS) with DB-5 column (60 m, 0.25 mm i.d., 0.25 m film thickness) to analyze the 209 kinds of PCB congeners. PCBs levels of air samples were detected to the range between 0.003 and $0.163pg-TEQ/m^3$. The PCBs congener of 162 kinds were detected in samples analysed using DB-5 column and 37 kinds peaks were overlapped with congeners more than one. It is difficult to isolate PCB 118/106 and PCB 105/127 in coplanar PCB, so it is likely to overestimate the concentration.. The distribution of coplanar-PCB congeners in origin source samples (Kanechlor and exhaust gas from incinerator) was compared with that in air samples, and PCB 81, PCB 77, PCB 126, and PCB 169 were higher in incinerator samples.

• The Korean Journal of Pesticide Science
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• v.20 no.1
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• pp.7-13
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• 2016

As of many organochlorine pesticides, polychlorinated biphenyls are ubiquitous organic contaminants, which can be found in the most environmental matrices. Their toxic effects include endocrinedisrupting activity. Most researches with these toxicants performed with mixtures of congeners, namely Aroclor and related study has been done in complex environmental matrix, rather than single biosystems or pure congeners. 5 congeners were synthesized and their fates in pure microbial culture (Aspergillus niger) were determined in this study. Among biphenyl and synthetic congeners, biphenyl, PCB-1 (2-chlorobiphenyl), and PCB-3 (4-chlorobiphenyl) were rapidly transformed to hydrophilic metabolites, followed by PCB-38 (3,4,5-trichlorobiphenyl), while the degradation of PCB-126 (3,3',4,4',5-pentachlorobiphenyl) was not observed. The amounts of transformation for biphenyl, PCB-1, PCB-3, and PCB-38 were 65, 38, 52, and 2% respectively. The major metabolites of the above congeners were identified as mono- and di-hydroxy biphenyls, which are known to give adverse endocrinological effects.

• 대한생식의학회:학술대회논문집
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• 2003.12a
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• pp.144-145
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• 2003

• Toxicological Research
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• v.22 no.1
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• pp.23-30
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• 2006

Among poly aromatic hydrocarbons, dioxin and PCBs are the most controversial environmental pollutants in our modern life. These pollutants are known as human carcinogens, and liver is the most sensitive target in animal cancer models. Specific aims of the study were focused on the mechanism of carcinogenesis in hepatocytes and the structure-activity relation among these diverse environmental chemicals. Because key mechanisms of dioxin-induced carcinogenesis in human epithelial cell model are the alteration of signal transduction pathway and PKC isoforms, the alteration of the signal transduction pathways and other factors associated with carcinogenesis were studied. Rat hepatocytes cultured under the sandwich protocols were exposed with the various concentration of dioxins and PCBs, and signal transduction pathway, protein kinase C isoforms, oxidant stress, and apoptotic nuclei were evaluated. Since it is important to understand the structure-activity relation among these chemicals to properly assess the carcinogenic potentials, the study analyzed the parameters associated with carcinogenic processes, based on their structural characteristics. In addition, signal transduction pathways and PKC isoforms involved in inhibition of UV-induced apoptosis were also analyzed to elaborate the tumor promotion mechanism of these chemicals. Induction of apoptosis by UV irradiation was optimal at $60\;J/m^2$ in primary hepatocyte in culture. Compared to non coplanar PCBs such as PCB 114 and PCB 153, coplanar PCBs such as PCB 77 and PCB126 showed a stronger inhibition of apoptosis induced by UV irradiation. Production of reactive oxygen species (ROS) was more stimulated by non-coplanar PCBs than coplanar PCBs with the most potent induction of ROS by chlorinated non-coplanar PCB. As compared to the level of induction by PCB126, non-coplanar PCB153 showed a higher increase of intracellular concentrations. Besides the alteration of intracellular calcium concentration, translocation of PKC from cytosolic fraction to membrane fraction was clearly observed upon the exposure of non-coplanar PCB. Taken together, the present study demonstrated that there is a potent structure-activity relationship among PCB congeners and the mechanism of PAH-induced carcinogenesis is structure-specific. The study suggested that more diverse pathways of PAH-induced carcinogenesis should be taken into account beyond the boundary of Ah receptor dogma to assess the health impact of PAH with more accuracy.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.121-126
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• 2004

Comamonas sp. strain DJ-12 is a 4-chlobiphenyl(4CB)-degrading bacterium that was reidentified from Pseudomonas sp. DJ-12. The genomic DNA was isolated from the strain DJ-12 and amplified by PCR with primers for cloning pcbABCD genes responsible for degradation of 4CB. The amino acid sequences deduced from the nucleotide sequences of pcbA1, pcbA2, pcbA3, pcbA4, pcbB, pcbC2, and pcbD2 genes showed 91, 87, 99, 87, 97, 90 and 87％ homologies with those of Pseudomonas sp. KKS102, respectively. The pcbC1D1 genes that are involved in the degradation of (4-chloro)1,2-dihydroxybiphenyl produced from 4CB by pcbAB gene products were previously reported in the recombinant plasmid pCU1 from Pseudomonas sp. DJ-12. However, the pcbC2D2 genes in the plasmid pCT4 and pCT5 cloned from Comamonas sp. DJ-12 in this study showed 51 and 62％ homologies with those of pcbC1D1 in their nucleotide sequences. The pcbC1D1 and pcbC2D2 genes were found by Southern hybridization to be located at different loci on the chromosome of DJ-12 strain. These results indicate that Comamonas sp. strain DJ-12 has two different sets of pcbCD genes responsible for deg-radation of (4-chloro)1,2-dihydroxybiphenyl.

• Analytical Science and Technology
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• v.16 no.4
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• pp.325-332
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• 2003

To analyze co-planar PCBs in food, the isotopic dilution method by high resolution gas chromatography/high resolution mass spectrometry was applied. Among 209 PCB congeners, 12 congeners (#77, #81, #126, #169, #105, #114, #118, #123, #156, #157, #167 and #189) were chosen as target compounds that were toxic congeners re-assessed by WHO in 1998. Milk and milk products including cheese and butter were collected as food samples. Samples were homogenized, spiked with the known amount of the standard mixture and extracted. After extraction, extracts were cleaned up by sulfuric acid impregnated silica gel, purified on silica gel and alumina column chromatography and then analyzed by HRGC/HRMS. As results, the overall recoveries were ranged from 83% to 106% and the limit of detection was about 0.1 pg/g at signal/noise>3. Levels of targets in the selected food samples were 0.001~0.107 pgWHO-TEQ/g.

• Korean Journal of Microbiology
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• v.32 no.2
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• pp.126-131
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• 1994

The pchABCD genes in Pseudomonas sp. DJ-12 speciyin degradation o 4-chlorobiphenyl(4CB) were cloned in Eschericia coli. The cloned cells of E. coli CU1 and CU101 showed to produce 2,3-dihydroxybiphenyl (2,3-DHBP) from 4-chlorobiphenyl by dechlorination, as Pseudomonas so. DJ-12 produced 2,3-DHBP from both biphenyl and 4CB. In particular, E. coli CU101 transformed with the recombinant plasmid of pCU101 revealed dechlorination activity to produce 2,3-DHBP from 4CB without production of 4-chlorobenzoic acid. Therefore, the pcbAB genes (2.2 kb in size) cloned from the chromosome of Pseudomonas sp. DJ-12 were found to have dechlorination activity on 4CB to produce 2,3-DHNP.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.126-127
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• 1999

PCBs(Polychlorinated Biphenyls)와 같은 미량 환경독성물질은 그 독성으로 인하여 지난 수십년간 환경 분야에서 중요한 연구분야가 되어왔으며 이에 대한 연구의 중요성이 최근의 내분비계 교란물질의 심각성으로 더욱 부각되고 있다. 특히 이 분야의 연구에서는 실제 측정을 통한 자료가 국내의 경우 분석과 측정의 어려움으로 인하여 거의 전무하다고 할 수 있다. 이에 본 연구에서는 대기-수체간의 PCBs 거동 특성을 실제 측정을 통하여 파악하기 위해 PCBs의 입자상 건식침적량을 측정하였다.(중략)