• 한국화재소방학회논문지
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• 제14권2호
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• pp.7-13
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• 2000

쿠션제조용; 마네킹 제조용 및 건축내장재용 폴리우레탄 봄의 열적특성을 조사하기 위하여 시차주사열량계(DSC, Differential Scanning Calorimeter) 및 열중량 분석기(TGA, Thermogravimetric Analysis)를 이용하여 온도에 따른 발열개시온도, 무게감량 등을 조사하였으며, 발화온도 측정방법 중 정온법을 이용하여 각 폴리우레탄 폼의 발화온도를 조사하였다. 이로부터 각 폴리우레탄 폼의 연소 조건에 따라 발생할 수 있는 유독성 가스를 가스분석기와 가스텍을 이용하여 조사하였다. 연구결과 시제품인 건축내장재용 폴리우레탄 폼의 분해개시온도가 다소 낮으며, 분해열이 매우 크게 나타났다. 발화온도는 $420^{\circ}$였다. 연소 시험시 $420^{\circ}$까지 무염연소의 형태를 가졌으며, $500^{\circ}$에서 유임연소가 발생하였다. 연소형태에 관계없이 연소온도의 증가에 따라 일산화탄소, 이산화탄소의 농도는 증가하였고, 유염연소를 나타내는 $500^{\circ}$에서 질소산화물이 10 ppm 이상 관찰되었다. 한편 유독성이 매우 강한 HCN의 경우 온도의 증가에 따라 크게 증가하였다.

• 한국재료학회지
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• 제2권1호
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• pp.35-42
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• 1992

실릴콘 산화막을 $CHF_3/C_2F_6$ 혼합가스를 사용하여 반응성이온 건식식각을 행할 때 실리콘 표면에 형성되는 잔류막과 손상충의 열적 거동을 X-선 광전자 분광기(XPS)와 이차이온 질량 분석기 (SIMS)를 사용, 연구하였다. 저항가열을 통한 in-situ 분석에 의해 폴리머 잔류막은 $200^{\circ}C$부터 분해가 시작되고 $400^{\circ}C$ 이상의 가열에서는 graphite 형태의 탄소 결합체를 형성하며 분해됨을 알았다. 질소 분위기하의 급속 열처리를 통해 잔류막의 열분해는 $800^{\circ}C$ 이상에서 완료되고 손상층을 형성하는 침투 불순원소의 기판 외부로의 확산이 관찰되었다.

• 상하수도학회지
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• 제24권6호
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• pp.775-788
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• 2010

The decomposition of 2,4,6-trinitrotoluene (TNT) and the mass balance of nitrogen (N) species as products were investigated in a UV/H2O2system by varying pH, concentrations of $H_2O_2$, and $O_2$. All experiments were conducted in a semi-batch system employing a 50 mL reaction vessel and a coil-type quartz-tube reactor. In contrast with previous studies employing batch mode, TNT decomposition in the semi-batch mode was proportionally enhanced by increasing $H_2O_2$ concentration to 10 mM (0.034%), indicatingthat an inhibitory effect of excess $H_2O_2$on hydroxyl radical (${\cdot}OH$) can be negligible. N compounds are released as $NO_2^-$ in the early stages of the reaction, but $NO_2^-$ is rapidly oxidized to $NO_3^-$ by means of ${\cdot}OH$. $NH_4^+$ was also detected in this study and showed gradually the increase with increasing reaction time. In this study, $NH_4^+$ production can involve the reduction of nitro group of TNT concurrent with the production of $NO_3^-$. Of the N species originating from TNT decomposition, 12 ~ 72% were inorganic forms (i.e. [$NO_3^-$] + [$NO_2^-$] + [$NH_4^+$]). This result suggests that the large remaining N portions indicate that unidentified N compounds can exist.

• Journal of Pharmaceutical Investigation
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• 제40권3호
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• pp.139-153
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• 2010

Nitrosative stress is defined as pathophysiological conditions that are related to covalent modifications of proteins by nitration/nitrosylation by forms of nitrogen oxide ($NO_x$), leading to DNA damage, ultimately, cell death. This type of stress condition appears to be associated with a number of disease states, including diabetes, inflammation and neurodegenerative diseases. Since these pathological conditions are frequently chronic in nature and, thus, require long-term treatment, changes in pharmacokinetics are likely to affect the therapy. Transporters are membrane proteins that facilitate the movement of substrates, including drugs, across plasma membranes of epithelial / endothelial cells. Since it is now increasingly evident that transporters are pharmacokinetically significant, functional alteration of transporters by this stress condition may have therapeutic relevance. In this review, experimental techniques that are used to study both in vivo and in vitro nitrosative stress are summarized and discussed, along with available literature information on the functional implication of transporters under conditions of nitrosative stress conditions. In the literature, both functional induction and impa irment were apparently present for both drug transporter families [i.e., ATP-binding cassette (ABC) and solute carrier families (SLC)]. Furthermore, a change in the function of a certain transporter appears to have temporal dependency by impairment in the early phase of nitrosative stress and induction thereafter, suggesting that the role of nitrosative stress is complex in terms of functional implications of the transporters. Although the underlying mechanisms for these alterations are not fully understood, protein nitration/nitrosylation appears to be involved in the functional impairment whereas transcript factor(s) activated by nitrosative stress may play a role, at least in part, in functional induction. Interestingly, functional induction under conditions of nitrosative stress has not been observed for SLC transporters while such impairment has been documented for both ABC and SLC transporters. Further investigations appear to be necessary to fully delineate the underlying reasons for these differences on the impact and importance of nitrosative stress conditions.

• Journal of Ecology and Environment
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• 제35권2호
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• pp.131-140
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• 2012

There are different types of compost used as soil conditioners and fertilizers. Plants can have different responses to different forms of compost. This field study was performed to examine the effects of different types of compost on growth factors of three dry rangeland species (Atriplex, $Atriplex$ $lentiformis$; Saltwort, $Seidlitzia$ $rosmarinus$; Haloxylon, $Haloxylon$ $persicum$) and soil properties. The experiment was conducted in the Fars Province of Iran during the year 2010-2011. Compost applications consisted of compost tea, solid compost (SC), solid and liquid mixture (MX) and no compost as the control. The study was a factorial experiment based on a randomized complete block design with 3 replications. The results showed that all the tested compost applications enhanced the growth traits of all three species. It was also demonstrated that the use of compost significantly increased the organic matter (1% probability level [PL]), nitrogen concentration (5% PL), phosphorous (5% PL) and potassium (5% PL) concentrations of the soil. The soil's pH level was unchanged (range, 7.3 to 7.6), and the sodium concentration was also significantly decreased (1% PL) by the use of compost. The higher responses were observed in canopy volume and soil sodium and the lower were observed in stem diameter and soil pH level. Among the three plants in the study, Atriplex showed the best response to the application of compost. Based on the results of this study, it can be recommended that the best compost application to increase growth and improve soil condition is the mixed compost (MX) for Atriplex and the SC for Saltwort and Haloxylon.

• Plant Resources
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• 제1권2호
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• pp.113-120
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• 1998

Soybean is an important crop because its seed has very high protein relative to others. The quality of soy protein is limited by the concentration of the sulfur-containing amino acids in the amino acid profile. Among the supply of various forms of 0.4mM sulfur as S nutrition during seed fill. only 0.4mM L-methionine can inhibit ${\beta}$-subunit synthesis completely and produce the highest glycinin-containing seeds. Compared to 0.4mM sulfate control, seeds supplied by 0.4mM L-methionine have lower ${\alpha}$-, no ${\beta}$-subunit, and highly increased glycinin without altering total protein concentration. Supply of 0.2mM cystine (0.4mM S) did not affect the accumulative pattern of seed storage protein (SSP) subunits. In the supply of L-methionine, 0.2mM treatment showed higher glycinin in seeds but 0.05mM resulted in lower glycinin than tile sulfate control. The relative abundance of ${\alpha}^`$-subunit was not altered by any N or S nutrition. Under 5mM nitrogen, protein concentration was increased about 3-5% by substituting ammonia for nitrate during seed fill independent of nutrition. The increase resulted in the only increase of 7S protein, mainly ${\beta}$-subunit. Our data suggest that the regulatory system of SSP genes responds to the balance between N and S assimilates supplied from mother plant. and controls the di fferential synthesis of their subunits for the maximum protein accumulation in developing soybean seed.

• 한국자기공명학회논문지
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• 제19권3호
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• pp.106-111
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• 2015

Helicobacter pylori (H. pylori) survives in acidic and fluctuating pH conditions of the stomach. The pH effect on H. pylori proteins is important for the advanced understanding of its evolution and viability, although this bacterium has the molecular machinery that neutralizes the acidic condition. HP1492 is known as a conserved NifU-like protein from H. pylori. NifU is a nitrogen fixation protein that mediates the transfer of iron-sulfur (Fe-S) cluster to iron-sulfur proteins like ferredoxin. Commonly, the monomeric reduced state of NifU can be converted to the dimeric oxidized state by intermolecular disulfide bond formation. Because it remains unclear that HP1492 actually behaves as known NifU protein, we first found that this protein can adopt both oxidized and reduced forms using size exclusion chromatography. Circular dichroism experiment showed that HP1492 is relatively well-structured at pH 6.5, compared to other pH conditions. On the basis of the backbone resonance assignment of HP1492, we further characterized the residues that are sensitive to pH using NMR spectroscopy. These residues showing large chemical shift changes could be mapped onto the secondary structure of the protein. Our results could provide the foundation for structural and biophysical studies on a wide spectrum of NifU proteins.

• Journal of Microbiology and Biotechnology
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• 제16권2호
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• pp.240-246
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• 2006

Cyanobacteria are present abundantly in rice fields and are important in helping to maintain rice fields fertility through nitrogen fixation. Many rice fields soil contain a high density of cyanobactera, and over 50% of cyanobacterial genera that are in existence in rice paddy fields are heterocystous filamentous forms. A total of 142 isolates of heterocystous filamentous cyanobacteria were screened from 100 soil samples taken from rice paddy fields in 10 different locations across Korea, classified according to their morphological characteristics under light microscopy, and their susceptibly to fungicides examined. The collected blue-green alga were classified into a total of 14 genera, including seven genera of filamentous cyanobacteria and seven genera of nonfilamentous cyanobacteria. In particular, 142 heterocystous filamentous cyanobacteria were isolated and classified into six genera, including Anabaena, Nostoc, Calothrix, Cylindrospermum, Nodularia, Scytomena, and Tolypotrix. Yet, over 90% of the heterocystous filamentous cyanobacteria isolated from the rice paddy fields belonged to two genera: Anabaena and Nostoc. The response of 129 $N_2-fixing$ cyanobacterial isolates, 53 Anabaena and 76 Nostoc, to 10 fungicides was then investigated. The results showed that the Nostoc spp. were more tolerant of the ten tested fungicides than the Anabaena spp., and among the ten tested fungicides, benomyl showed the highest acute toxicity to Anabaena spp. and Nostoc spp. In conclusion, although benomyl is a very useful agent to control phytopathogenic fungi, the application of this fungicide to rice fields should be considered because of its toxicity to the heterocystous filamentous cyanobacteria.

• Asian Journal of Atmospheric Environment
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• 제11권1호
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• pp.29-32
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• 2017

Ozone concentration in Tokyo Metropolitan area is one of the most serious issues of the local air quality. Tropospheric ozone is formed by radical reaction including volatile organic compound (VOC) and nitrogen oxides ($NO_x$). Reduction of the emission of reactive VOC is a key to reducing ozone concentrations. VOC is emitted from anthropogenic sources and also from vegetation (biogenic VOC or BVOC). BVOC also forms ozone through $NO_x$ and radical reactions. Especially, in urban area, the BVOC is emitted into the atmosphere with high $NO_x$ concentration. Therefore, trees bordering streets and green spaces in urban area may contribute to tropospheric ozone. On the other hand, not all trees emit BVOC which will produce ozone locally. In this study, BVOC emissions have been investigated (terpenoids: isoprene, monoterpenes, sesquiterpenes) for 29 tree species. Eleven in the 29 species were tree species that did not emit BVOCs. Three in 12 cultivars for future planting (25 %) were found to emit no terpenoid BVOCs. Eight in 17 commonly planted trees (47%) were found to emit no terpenoid BVOC. Lower-emitting species have many advantages for urban planting. Therefore, further investigation is required to find the species which do not emit terpenoid BVOC. Emission of reactive BVOC should be added into guideline for the urban planting to prevent the creation of sources of ozone. It is desirable that species with no reactive BVOC emission are planted along urban streets and green areas in urban areas, such as Tokyo.

• 생태와환경
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• 제50권4호
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• pp.470-477
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• 2017

본 연구는 낙동강 상류에 위치한 내성천과 지류들을 대상으로 총 15개의 지점에서 2016년 5월, 8월 및 10월의 총 3회에 걸쳐 이화학적 환경요인들과 부착돌말 군집의 특성을 분석하고, 생물학적 방법인 DAIpo와 TDI를 이용하여 수질을 평가하였다. 내성천 수계에서 출현한 부착돌말류는 2목 3아목 9과 35속 145종 16변종 2품종으로 구성된 총 163종이 출현하였다. Cocconeis placentula var. lineata는 모든 지점에서 출현하였으며, Achnanthes lanceolata, Nitzschia fonticola, Nitzschia inconspicua와 Reimeria sinuate는 내성천의 보편적인 분류군들로 조사되었다. Nitzschia inconspicua와 Achnanthes minutissima가 주요 우점종으로 출현하였다. CCA 분석 결과, 부착돌말 종조성은 전기전도도와 총질소에 가장 많이 영향을 받는 것으로 나타났다. DAIpo를 이용한 생물학적 수질평가 결과, 내성천의 DAIpo는 평균 62.38로 B등급이나, TDI로 평가한 결과, 내성천의 TDI는 평균 66.12로 C등급으로 나타났다.