• Bulletin of the Korean Chemical Society
• /
• 제24권9호
• /
• pp.1276-1280
• /
• 2003

Thermal behavior of bromphenols was investigated by direct pyrolysis at high temperature. The thermal degradation products formed by the pyrolysis of mono-bromophenols (o-, m-, and p-) were identified by gas chromatography-mass spectrometry. During the pyrolysis reactions, several kinds of dioxins and furans were produced, and the relative ratio of pyro-products was dependent on the substituted position of bromine in phenolic structure due to the effect of symmetry and steric hindrance. The formation of dioxins can be explained by the phenoxy radical addition and Br atom elimination at an ortho-carbon site on phenolic structure. On the other hand, the formation of furans can be explained by the ortho-ortho carbon coupling of phenoxy radicals at unsubstituted sites to form o, o'-dihydroxydiphenyl intermediate via its keto-tautomer, followed by $H_2O$ elimination. The pyrolysis temperature has also a substantial effect on the dimerized products quantities but little effect on the type of pyro-products. Moreover, the formation mechanism of pyro-products was suggested on the basis of products identified.

• Bulletin of the Korean Chemical Society
• /
• 제32권10호
• /
• pp.3702-3706
• /
• 2011

The conformation of a neuropeptide, substance P (SP), in isotropic (q = 0.5) acidic bicelles was investigated using two-dimensional NMR techniques. By the nuclear Overhauser effect (NOE) cross peaks between SP and long-chain lipid molecules SP was probed to bind on the flat surface of the disc-like bicelles. Structural analysis of NMR data indicated that the helical conformation of SP extended to the C-terminal region of Leu10 as well as in the mid-region from Pro4 to Phe8. As compared with the conformations of SP bound on the sodium dodecylsulfate (SDS) or the dodecylphosphocholine (DPC) micelles with curved surfaces, the surface curvature of the membrane mimics was found to be one of the major factors inducing the biologically relevant conformation of SP. The negative surface charge of the membrane is also a key factor inducing both the binding of SP on the membrane and its biologically active structure.

• Toxicological Research
• /
• 제21권2호
• /
• pp.99-105
• /
• 2005

Photo-mutagenic compounds have been known to alter skin cancer rates by acting as initiators or by affecting subsequent steps in carcinogenesis. The objectives of this study are to investigate the utility of photo-chromosomal aberration (photo-CA) assay for detecting photo-clastogens, and to evaluate its ability to predict rodent photocarcinogenicity. Photo-CA assay was performed with 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 alpha-adrenergic 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). For the best discrimination between the test substance-mediated genotoxicity and the undesirable genotoxicity caused by direct DNA absorption, a UV dose-response of the cells in the absence of the test substances was firstly analyzed. All 5 test substances showed a positive outcome in photo-CA assay, indicating that the photo-CA test is very sensitive to the photo-genotoxic effect of UV irradiation. With this limited data-set, an investigation into the predictive value of this photo-CA test for determining the photo-carcinogenicity showed that photo-CA assay has the high ability of a test to predict carcinogenicity. Therefore, the photo-CA test using mammalian cells seems to be a sensitive method to evaluate the photo-carcinogenic potential of new compounds.

• Preventive Nutrition and Food Science
• /
• 제13권3호
• /
• pp.241-244
• /
• 2008

Methanol extracts were prepared from Z. schinifolium leaf and successively fractionated with chloroform, butanol, and water. The butanol fraction exhibited the highest antioxidative activities. Therefore the butanol fraction was purified and a chemical structure was identified by $^1H-^{13}C-NMR$ spectra, and FT-IR. The isolated antioxidative substance was identified as quercitrin.

• 한국화재소방학회논문지
• /
• 제31권1호
• /
• pp.81-88
• /
• 2017

본 연구에서는 화학사고의 인명사고 특성을 분석하기 위해 화학사고의 유형, 사고 발생 장소, 사고 사업장 규모, 사고 물질 등에 따른 화학사고, 인명사고, 사망자, 부상자 등을 조사하여 분석하였다. 화학사고로 인한 인명사고 및 인명피해 현황을 살펴보면 "화학물질관리법" 시행 이전인 2013년과 2014년에 인명사고는 각각 16건, 17건이었고, 법 시행 이후인 2015년과 2016년에는 각각 46건, 23건으로 조사되었다. 전체 화학사고와 인명사고 모두 유 누출에 의한 사고가 가장 많았고, 인명피해 현황 또한 가장 많았다. 화학사고 발생 장소에 따른 사고 및 인명피해 현황을 조사한 결과 사업장에서 모든 조사항목이 가장 높은 수치를 나타냈다. 사고다발 상위 10개 물질을 조사한 결과 폐산을 제외한 9개 물질이 모두 유해화학물질이면서 사고대비물질과 유독물에 포함되는 물질이었다. 따라서, 유 누출 사고, 사고에 취약한 사업장, 위험 화학물질 등에 대한 관리를 강화시킬 필요가 있다.

• 한국환경보건학회지
• /
• 제45권5호
• /
• pp.465-473
• /
• 2019

Objectives: A variety of industries handling hazardous chemicals emit odorous substances. Based on the emission characteristics of major odor substances from the results of hazardous chemical substance emissions, we will define basic data for improving the management methods of odorous substances. Methods: A survey of hazardous pollutant emissions for 2010-2016 was conducted through the Pollutant Release and Transfer Register homepage. Eight kinds of designated odor substances (ammonia, hydrogen sulfide, dimethyl disulfide, acetaldehyde, styrene, toluene, xylene, methyl ethyl ketone) provided the study subjects. The status of chemical accidents for the target substances was analyzed using the Chemistry Safety Clearing-house system. Results: From 2010 to 2016, it was found that more than 30% of businesses that emitted odorous substances accounted for more than 50% of the total emissions of the eight substances. Emissions of xylene, toluene, methyl ethyl ketone, and ammonia were found, in that order, and they made up more than 90% of the total emitted. By region, about 70% of odorous substances were emitted in the top-four regions: Gyeongsangnam-do Province, Ulsan, Gyeonggi-do Province, and Jeollanam-do Province. Conclusion: Recently, the amount of chemical emissions has been continuously increasing, including those that can cause odor. Odorous substances can be a serious risk to the lives of local residents. Systematic research is needed for the health protection of residents.

• 대한화학회지
• /
• 제13권4호
• /
• pp.333-339
• /
• 1969

Synthesis and chemical properties of 1,4-bisdiazo-2-butene have been studied. 1,4-Bisdiazo-2-butene which was very unstable produced in protic solvents 1,3-butadiene and one unidentified substance instead of ring compounds. The reaction in aprotic solvents remains for further investigations.

• 한국콘텐츠학회논문지
• /
• 제12권5호
• /
• pp.323-330
• /
• 2012

본 연구는 안전보건 관리에 있어 관심이 미약하였던 대학 실험실에서의 유해화학물질 발생 수준과 그로 인한 위험성을 알아보기 위하여 2010년 5월 26일부터 6일간 서울시에 소재한 K대학을 대상으로 학과별 실내 오염인자를 측정, 분석하였다. 그 결과 MSDS 비치 여부와 노출저감시설 설치 유무, 보호구 지급 현황은 기초과학실험실인 화학과, 물리학과, 의학과 등에서의 관리가 비교적 양호하였으며, 치의학과, 미술학과에서는 유해화학물질 관리를 위한 활동이 미흡한 것으로 조사되었다. 또한 실험실 내의 폼알데하이드와 총휘발성유기화합물 농도는 미술학과가 다른 실험실에 비하여 현저히 높게 검출되었고 유사학과별로 집단화 한 그룹의 폼알데하이드 농도는 미술학과, 생활과학과가 포함된 기타학과에서 높게 나타나 유의한 차이를 보였다. 이상의 결과로 볼 때 전반적으로 화학물질 노출로 인한 건강영향에 대한 인식이 저조하고 그에 대한 관리가 미흡한 학과의 실험실에서 높은 수준의 위험성에 노출되고 있는 것으로 판단되었다.

• Bulletin of the Korean Chemical Society
• /
• 제24권8호
• /
• pp.1163-1168
• /
• 2003

The structures of molecular species of galactolipids, such as monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG), isolated from wheat flour have been investigated using negative-ion electrospray ionization (ESI) mass spectrometry interfaced with high performance liquid chromatography (HPLC). According to the result of HPLC analysis, MGDG and DGDG were found to consist of mixtures of five and four molecular species, respectively. The galactolipids have been also analyzed to determine their fatty acid compositions, using HPLC/ESI-MS combined with in-source (or cone voltage) fragmentation. HPLC/ ESI-MS is very useful for one-step analysis of mixtures of galactolipids with a small sample quantity. Especially, the carboxylate anions produced in in-source fragmentations of the negative-ion of each component separated by HPLC provide valuable information on the composition of its fatty acyl chains.

• 한국의류학회지
• /
• 제26권10호
• /
• pp.1436-1442
• /
• 2002

In this paper, the effect of the loess and mud of an inorganic substance dyed on cotton knitting fabrics have been studied The structure and chemical composition of loess and mud was analyzed. And the Far-Infrared emissivity and emission power, colorfastness, anti-bacterial properties cotton knitting fabrics dyed with loess and mud were also evaluated. The structure and chemical composion of loess and mud was almost identical structure and to be alike main components were SiO$_2$, Al$_2$0$_3$ and Fe$_2$O$_3$. The cotton hitting fabrics dyed with loess and mud have good colorfastness and anti-bacterial properties. when the dyed fabrics was after-treated with diphenyl ether, the anti-bacterial property were improved. Far-Infrared emissivity and emission power cotton knitting fabrics dyed with loess and mud have very good.