• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2003년도 춘계학술대회
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• pp.194-194
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• 2003

The International Agency for Research on Cancer (IARC, 1989) has classified whole diesel exhaust as probably carcinogenic to humans. Diesel exhaust particulate matter (DPM) adsorbs different chemical substances including PAHs and nitroarenes. DPM is emphasized because it is a major component of diesel exhaust, it is suspected of contributing to a health hazard. Diesel exhaust is a complex mixture of carbon particles and associated organics and inorganics, and it is not known what fraction or combination of fractions cause the health effects [cancer effects, noncancer effects (respiratory tract irritation/inflammation and changes in lung function)] that have been observed with exposure to diesel exhaust. In order to identify which chemical classes are responsible for the majority of the observed biological activities, we performed a particular biological/chemical analysis. Respirable particulate matter (PM2.5: <2.5mm) was collected from diesel engine exhaust using a high-volume sampler equipped with a cascade impactor. Particulate oganic matter was extracted by the dichloromethane/sonication method and the crude extract was fractionated according to EPA recommended procedure into seven fractions by acid-base partitioning and silica gel column chromatography. We examined genotoxic potentials of diesel exhaust particulate matter using novel genotoxicity tests, which are rapid, simple and sensitive methods for assessing DNA-damage at the DNA and chromosomal level (comet assay, in vitro MN test and Ames test). Higher genotoxic potency was observed in non polar fractions and several PAHs were detected by GC-MS, such as 1,2,5,6 dibenzanthracene, chrysene, 1,2-benzanthracene, phenanthrene and fluoranthene.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.209-212
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• 2009

It has been widely reported that carbide-free bainitic steels or super-bainite WP (SB-TRIP) steels for the automotive industry are a new family of steels offering a unique combination of high strength and ductility. Hence, it is important to exactly evaluate the volume fraction of RA and to identify the 3-D morphology of constituent phases, because it plays a crucial role in mechanical properties. Recently, as electron back-scattered diffraction (EBSD) equipped with focused ion beam (FIB) has been developed, 3-D EBSD technique for materials science are used to these steels. Moreover, newly developed atom probe tomography (APT) technique can provide the exact distribution and chemical concentration of alloying elements in a sub-nm scale. The APT analysis results indicate exactly the distribution and composition of alloying elements in the austenite and bainite phases of SB-TRIP steels with the atomic-scale resolution. And thus, no partitioning of aluminum and manganese atoms was showed between the austenite containing $7.73{\pm}0.39$ at% C and the bainitic ferrite associated with $0.22{\pm}0.06$ at% C in the SB-TRIP steel.

• Asian-Australasian Journal of Animal Sciences
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• 제19권4호
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• pp.507-513
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• 2006

Changes of in vitro true digestibility (IVTD) of Napiergrass (Pennisetum purpureum) were determined by a filter bag system, and their relationships to chemical composition, leaf to stem ratio, plant height, geographic location, climatic factors and harvest interval were studied and used to develop prediction models for the crude protein (CP), acid-detergent fiber (ADF), and neutral-detergent fiber (NDF) contents and IVTD. Partitioning the total variance of IVTD of Napiergrass showed that 80% was attributable to the effect of harvest interval. Days of growth, plant height, leaf/stem ratio, CP, ADF and NDF of Napiergrass had highly significant relationships (p<0.01) with IVTD. The highest coefficient of correlation between the ADF, NDF, and IVTD of Napiergrass and growth degree days was obtained when the base temperature was set at $0^{\circ}C$. Growth degree days could predict ADF, NDF, and IVTD of Napiergrass more accurately than plant height, and plant height is not suitable to predict IVTD.

• 소성∙가공
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• 제19권1호
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• pp.44-49
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• 2010

It has been widely reported that carbide-free bainitic steels or super-bainite TRIP (SB-TRIP) steels for the automotive industry are a new family of steels offering a unique combination of high strength and ductility. Hence, it is important to exactly evaluate the volume fraction of RA and to identify the 3-D morphology of constituent phases, because it plays a crucial role in mechanical properties. Recently, as electron back-scattered diffraction (EBSD) equipped with focused ion beam (FIB) has been developed, 3-D EBSD technique for materials science are used to these steels. Moreover, newly developed atom probe tomography (APT) technique can provide the exact distribution and chemical concentration of alloying elements in a sub-nm scale. The APT analysis results indicate exactly the distribution and composition of alloying elements in the austenite and bainite phases of SB-TRIP steels with the atomic-scale resolution. And thus, no partitioning of aluminum and manganese atoms was showed between the austenite containing $7.73{\pm}0.39$ at% C and the bainitic ferrite associated with $0.22{\pm}0.06$ at% C in SB-TRIP steel.

• 환경영향평가
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• 제9권4호
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• pp.301-314
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• 2000

Marine surface sediments in the vicinity of Samcheonpo coal-fired power plant were analyzed by a total analysis($HF+HNO_3+HClO_4$) and sequential extraction procedure for heavy metals in order to investigate the total concentrations and geochemical phases of heavy metals. The result showed that the concentrations of Cr, Cu, Fe and Zn were within ranges typical for coastal areas, which reflected the mineralogical composition of the sediments in the studied area. However, the distributions of Cd, Co, Mn, Ni and Pb were rather different from the former, indicating that these heavy metals had a different origin, or that they were affected by a different geochemical mechanism. Chemical partitioning of heavy metals using sequential extraction procedure revealed that Cu, Fe, Pb, Zn were significantly bound to the residual phases of the sediments, whereas carbonate phases contained considerable amounts of Mn. The significant association of Pb with the exchangeable fraction also indicated that Pb was more mobile and bioavailable than Cu, Fe, Mn, Zn.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1986년도 추계학술대회
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• pp.516.2-516
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• 1986

DNA subfragments, sopA, sopB, and sopC supporting stable maintenance of an oriC plasmid, were derived from mini-F plasmid DNA (EcoRI restriction fragment, f5) after digestion with restriction endonucleases, and cloned in vector plasmid pBR322. The recombinant plasmid obtained were introduced into E. coli KY7231 and E. coli CSR603, and proteins specified by the mini-F fragments were analysed by SDS-polyacrylamide gel electrophoresis. Two proteins encoded by the F fragments were detected, having molecular weights of 41,000 and 37.000. The sopA protein (41K) encoded by a plasmid pXX288 was observed in the cytoplasm, whereas the sopB protein (37K) encoded by a plasmid pXX157 was in the membrane fraction. There was no novel protein band detected in the cell with a plasmid pXX300, which contained sopC fragment. Gene products of a plasmid pXX167, which is comprised of sopA, sopB, and sopC, were not detectable. Fluorography after one and two dimensional gel electrophoresis of the lysates showed that these two proteins were overproduced in the cells which were allowed to incorporate radioactive amino acid after plasmid amplification by chloramphenicol treatment. The isoelectric points of the sopA and sepB proteins were 6.6 and 7.0, respectively.

• Journal of the korean society of oceanography
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• 제32권3호
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• pp.156-161
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• 1997

The biogeochemical cycle of silver has rarely been reviewed, even though the silver ion (Ag$^{\times}$) is extremly toxic to some organisms. Its concentration is still rising sharply because of increased anthropogenic activity, specifically the discharge from the film industry (mainly, silver thiosulfate: Ag (S$_2$O$_3$)${^3-}_2$). Recently, a number of researchers have quantified the major fluxes and reservoirs of silver in the open ocean, bays, and estuaries. A review of the available information for Ag cycling in the open ocean shows that the riverine input (from human activity and weathering processes: 7${\times}$10$^6$ kg/yr and 5${\times}$10$^6$ kg/yr, respectively) is the dominant source of Ag to estuarine and coastal regions. Most of the silver (90% of riverine input silver) is removed in coastal sediments by the physical-chemical character of silver due to its high partitioning with particulate matter. On the other hand, in the open ocean the atmospheric input (wet and dry deposition: 1.48${\times}$10$^6$ kg/yr and 1.94${\times}$ 10$^5$ kg/yr, respectively) becomes more important as a source of silver than riverine input. The residence time of silver calculated from available data is 1250 yrs in the deep ocean below 500 m, but only 3 yrs in the surface ocean.

• 한국환경과학회지
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• 제12권11호
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• pp.1145-1157
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• 2003

The surface sediments inside Hallim Harbor, one of the major harbors of Jeju Island, were sampled three times (June, September and December, 2001) and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), recommended by US-EPA as priority pollutants, to assess their distribution levels and to suggest their possible origins. The concentrations of PAHs ranged from 19 to 496 ng/g on a dry weight basis with a mean value of 245 ng/g, and the levels were low to moderate in comparison with other areas in the world. Based on comparisons of individual and total PAH concentrations with effects-based and equilibrium partitioning-based on sediment quality guidelines, the potential for the biological effects were expected to be low. The sedimentary PAHs may be correlated with organic carbon and mud contents to some extent. From the examinations of the four PAH origin indices, such as LMW/HMW (low molecular weight 2-3 ring PAHs over high molecular weight 4-6 ring PAHs), phenanthrene/anthracene ratio, fluoranthene/pyrene ratio, chrysene/benzo〔a〕anthracene ratio, it can be concluded that the sediment PAH contaminations were ascribed to both pyrolytic and petrogenic origins.

• Food Science and Biotechnology
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• 제15권5호
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• pp.781-785
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• 2006

The chemical compositions of the seeds of the safflower (Carthamus tinctorius L.) plant were evaluated to determine possible compound having proliferative effects on human osteoblast cells. Three-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test and alkaline phosphatase (ALP) activity were used to assess the effects of the isolates on the human osteoblast-like line (Saos-2). Activity guided fractionation led to the isolation of ALP activating lignin and alkaloid glycosides through the extraction of the seeds, solvent partitioning and repeated silica gel and octadecyl silica (ODS) column chromatographic separations. The data from Nuclear Magnetic Resonance (NMR), Mass (MS), and Infrared (IR) analyses enabled the determination of the chemical structure and characterization of two compounds as a tracheloside and an N-(p-coumaroyl)-serotonin mono-${\beta}$-D-glucopyranoside. These two compounds showed respectively $149.2{\pm}4.2$ and $138.9{\pm}3.5%$ ALP activity compared to the control when evaluated at a concentration of $100\;{\mu}g/mL$.

• 분석과학
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• 제29권5호
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• pp.225-233
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• 2016

입자 표면에 고분자를 화학적으로 접목하는 것은 수용성 액체 이상 시스템(ATPS)과 같이 분리된 액체 층에서 마이크로/나노입자를 선택적으로 분배시키는데 중요한 구실을 한다. 본 연구에서는 덱스트란, 폴리에틸렌 글리콜, 알부민을 화학적으로 폴리스티렌 자성 마이크로입자 표면에 화학적으로 부착시켰다. 분배 현상을 역전시킬 수 있는 긴 고분자 사슬의 부착은 일차 아민 작용기를 가진 다양한 고분자를 p-톨루엔술폰산(토실)기를 부착시킨 폴리스티렌 자성 마이크로입자와의 S_N2 치환에 의해 간단히 수행될 수 있었다. 이 후 적외선 현미경을 사용하여 마이크로입자의 표면 변화의 유무를 검사하였다. 반응 후 입자들은 세 가지 폴리머 모두 N-H 신축 진동 피크를 보였으며 대부분의 주요 피크들의 위치는 반응 전후에 유사하였으나 지문 영역에서 구별 가능한 차이를 보였다.