Polystyrene composites containing crosslinked polystyrene-multiwalled carbon nanotube balls

Kwon, Soon-Min,Kim, Hun-Sik,Kim, Don-Young,Yun, Young Soo,Jin, Hyoung-Joon Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of applied polymer science Vol.110 No.6

<P>Crosslinked polystyrene-multiwalled carbon nanotube (PS-MWCNT) balls, which act as conductive microfillers, were prepared by the in situ suspension polymerization of styrene with MWCNTs and divinyl benzene (DVB) as a crosslinking agent. The diameters of the synthesized crosslinked PS-MWCNT balls ranged from 10 to 100 μm and their electrical conductivity was about 7.7 × 10<SUP>−3</SUP> S/cm. The morphology of the crosslinked PS-MWCNT balls was observed by scanning electron microscopy and transmission electron microscopy. The change in the chemical structure of the MWCNTs was confirmed by Raman spectroscopy and Fourier transform infrared spectroscopy. The mechanical and electrical properties of the PS/crosslinked PS-MWCNT ball composites were investigated. It was found that the tensile strength, ultimate strain, Young's modulus, and impact strength of the PS matrix were enhanced by the incorporation of the crosslinked PS-MWCNT balls. In addition, the mechanical properties of the PS/crosslinked PS-MWCNT ball composites were better than those of the PS/pristine MWCNT composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008</P>

장기간 항갑상선제 투여 후 임의 중단 뒤 재복용시 발생한 무과립구증 1 예

김승만;김태영;박수영;배영환;서영경 정은주;김태균;권민정;박정현;이순희 인제대학교 2011 仁濟醫學 Vol.32 No.-

Agranulocytosis, one of the major side effects of antithyroid a gents, probably occurs in less than 0.25% of cases treated with antithyroid agents. It usually occurs within the first several weeks or months after the initiation of therapy, when drug dosage is higher. Most reported cases of agranulocytosis have occurred during the first 3 months of therapy. We describe here a rare case that did not experience the side effect for 6 years of antithyroid agent treatment but presented with agranulocytosis in one month after re-exposure. It suggests that the major side effect such as agranulocytosis can occur in patients who had undergone prior uneventful antithyroid drug therapy.

노화가 인체 중간엽 줄기세포로부터 조골세포로의 증식 및 분화에 미치는 영향

백기현,태현정,오기원,이원영,조정기,권순용,강무일,차봉연,이광우,손호영,강성구,김춘추 대한내분비학회 2003 Endocrinology and metabolism Vol.18 No.3

연구배경: 일반적으로 골다공증과 연관된 위험인자로는 연령, 폐경, 약물, 불충분한 칼슘섭취, 만성질환 및 운동부족 등이 있는데, 특히 노화가 진행할수록 골밀도가 감소하는 것은 잘 알려져 있다. 노화와 관련하여 진행되는 골소실은 조골세포 및 전구조골세포의 기능적 결핍에 의한 골형성의 감소가 주요한 요인으로 여겨지고 있다. 그 동안 연령이 조골모 세포의 양과 조골모 세포로부터 성숙조골세포로의 분화 및 증식에 미치는 영향에 대한 일부 보고들이 있었으나 아직 일치된 견해는 없는 형편이다. 방법: 다양한 연령의 사람으로부터 골수를 채취, 중간엽 줄기세포가 포함된 단핵세포를 분리한 후 조골세포로 분화하기 좋은 조건하에서 배양하였다. 대상군은다시 젊은군과 노령군으로 구분하여 다양한 변수를 비교 분석하였다. 일차배양에서는 CFU-F를 계수하여 골수내 중간엽 줄기세포의 수를 추산하였고, 칼슘측정을 통하여 기질의 무기화 정도를 비교하였다. 계대배양후 이차배양에서는 시기별로 알카리성 포스파타제 활성도를 측정하고 오스테오칼신 mRNA의 발현을 관찰하여 젊은군과 노령군 사이의 증식능 차이를 비교하였다. 또한 이차배양 시기별로 MTT 측정을 하여 양군간에 증식능 차이가 있는지 알아보았다. 결과: 1. 일차배양 15일째에 평균 CFU-F의 수는 젊은군에서 유의하게 많았다(젊은군 148.3±28.9, 노령군 54.3±9.1, p=0.02). CFU-F의 평균면적은 젊은군에서 넓은 경향을 보였으나 통계적으로 유의하지는 않았다. 2. 일차배양 17일 경과 후 양군간에 기질 칼슘 침착정도는 유의한 차이를 보이지 않았다(젊은군 103.6±50.6, 노령군: 114.0±56.5, p=NS). 3. 이차배양 10일째에 젊은군에서 알카리성 포스파타제 활성도가 고령군에 비해 유의하게 높았다(젊은군: 935.5±115.0 U/mg, 노령군: 578.4±115.7U/mg,p.0.05). 고령군에서는 시간 경과에 따른 변화가 미약했으며 전반적으로 알카리성 포스파타제의 활성도가 젊은군에 비해 낮았다. 4. 이차배양도중 오스테오칼신 mRNA의 발현은 배양시기별로 젊은군에 비해 고령군에서 더 낮은 경향을 관찰할 수 있었다. 5. 이차배양 10일과 15일에 젊은군에서 노령군보다세포증식이 유의하게 증가된 양상을 보였다(10앓 젊은군 0.73±0.05, 노령군 0.58±0.04, p=0.05, 15일; 젊은군 0.80±0.05, 노령군 0.70±0.03, p=0.05).결론: 이상의 연구에서 저자들은 노령군에서 젊은군보다 골수 내 중간엽줄기세포의 수가 적고, 노령군에서 유래한 전구조골세포의 성숙조골세포로의 증식 및 분화가 젊은군 보다 감소해 있는 것을 관찰할 수 있었다. Background: Osteoblasts originate from osteoprogenitor cells in bone marrow stroma, termed mesenchymal stem cells (MSCs) or bone marrow stromal cells. Each MSC forms colonies (colony forming units-fibroblasts [CFL-Fs]) when cultured ex vivo. There are some reports about the age-related changes of the number and osteogenic potential of osteoprogenitor cells, but any relationship has not been clearly established in humans. In this study, we counted MSCs using CFU-Fs count and examined the proliferative capacity and differentiation potential of osteoprogenitor cells. Finally, we analyzed how these parameters varied with donor age. Methods: Bone marrow was obtained from the iliac crest of young (n=6, 27.2±8.6 years old) and old (n= 10, 57.4k6.7 years old) healthy donors. Mononuclear cells, including MSCs, were isolated and cultured in osteogenic medium. In primary culture, we compared the colony-forming efficiency of MSCs between the two groups and determined the matrix calcification. When primary culture showed near confluence, the cells were subcultured. Alkaline phosphatase activity, osteocalcin expression by RT-PCR and proliferative potential by MTT assay were examined by the time course of secondary culture. Results: At the 15th day of primary culture, the mean number of CFU-Fs was significantly higher in the younger donors (young: 148.3±28.9, old: 54.3±9.1, p=0.02) and the mean size of CFL-Fs was also larger in the younger donors than the older donors. However, matrix calcification was not different between the two groups (young: 103.6±50.6, old: 114.0±56.5, p=NS). In secondary culture, alkaline phosphatase activities were significantly lower in the older donors. The younger donors showed peak alkaline phosphatase activity at day 10, while the older donors didn't showed a remarkable peak (young: 935.5±115.OU/mg, old: 578.4±115.7U/mg, p<0.05). Total cell number as a proliferative index increased progressively during the secondary culture and a significantly greater cell number was noted in the younger donors. Osteocalcin expression was generally upregulated in the younger donors, but this was not statistically significant. Conclusion: Our study shows that the number of osteoprogenitor cells is decreased during aging and that the proliferative capacity and differentiation potential of osteoprogenitor cells seem to be reduced during aging (J Kor SOC Endocrinol 18:296-305, 2003).

유기과산화물의 합성방법에 관한 고찰

권순경,박영남,박해선 德成女子大學校 藥學硏究所 2004 藥學論文誌 Vol.15 No.1

Compounds with an oxygen-oxygen single bond, are called peroxides, which undergo homolysis readily by heating or irradiation with light, because the oxygen-oxygen bond is weak. The formed products are radicals, which are short-lived and highly reactive. This property is used as initiator in radical chain reaction such as halogenation and many kinds of polymerization. Peroxides are one of the important oxidants and initiators. In this paper synthetic methods of peroxides and mechanisms are reviewed.

바나듐과 크롬의 쿠페론 착물의 전기화학적 행동의 차이

권영순,이상미,정미영,박소영 가톨릭대학교 자연과학연구소 2004 자연과학논문집 Vol.25 No.-

바나듐과 크롬의 쿠페론 착물의 전기화학적 행동을 아세트산 완충용액(pH 5.0)과 붕산염 완충용액(pH 9.5)에서 조사해 본 결과 크롬-쿠페론 착물의 환원봉우리전위(E_(ct)^(p))가 쿠페론의 봉우리전위(E₁^(p))보다 작다 (E_(ct)^(P) < E₁^(P)). 붕산염 완충용액에서 크롬-쿠페론계의 전도된 봉우리가 크게 나타나는 것은 E_(ct)^(P)와 E₁^(P)의 차이가 큰 때문인 것으로 생각된다 (ΔE = 0.40V). When the peak potentials of V-cupferron and Cr-cupferron complex compare at both buffer solution(pH 5.0 and pH 9.5), the peak potential of Cr-cupferron(E_(ct)^(P)) is smaller the peak potential of cupferron (E₁^(P)) at both buffer solution (E_(ct)^(p)) < E₁^(p)). The appearance of larger inverted peak of Cr-cupferron in borate buffer solution results from large difference of E_(ct)^(p) and E₁^(p) (ΔE=0.40 V).

5-Phenyl-4,5-dihydro-1H-benzazepin-2 one의 합성

권순경,박영남 德成女子大學校 2003 德成女大論文集 Vol.32 No.-

The first of benzodiazepines was chlordiazepoxide, which was marketed as tranquilizer under the trade name Librium. Now benzodiazepine derivatives are prescribed for insomnia and muscle relaxants as well as to treat anxiety. As benzodiazepines used widely, drug abuse becomes a serious social problem because of psychological and physical dependence and over deaths. It is necessary to develop the in vitro diagnostic reagents for the detection of small amount of abused drugs in urines. Because accuracy and convenience for point of care testing systems are indispensable, immunological determinations are fit for our requirements, which react with specific drug antigens and are able to detect small amount of drugs in urine. A benzazepinone derivative(4), which will be used as a component of the reagents for detecting benzodiazepine drugs or their metabolite in urine, was synthesized from 5-phenyltetrahydrofuran-2-one(1) as a key intermediate.

아미노산용액에서 팔라듐의 전기화학적 행동

권영순,이수진 가톨릭대학교 자연과학연구소 1998 자연과학논문집 Vol.19 No.-

팔라듐을 0.01M proline 용액에서 펄스 차이 폴라로그래피법으로 정량하였다. 검출 한계는 4.5×10^(-8)M Pd(Ⅱ)이고 봉우리 전류가 선형인 농도 범위는 6.0×10^(-8)~2.0×10^(-7)M Pd(Ⅱ)이었다. 촉매 수소 전류가 생성되는 메카니즘은 chemisorption이 일어나는 BC과정임을 알 수 있었다. The measurement of trace palladium in 0.01M proline solution by differential pulse polarographic method is described. In this medium the detection limit and the dynamic range are 4.5×10^(-8)M and 6.0×10^(-8)~2.0×10^(-7)M for palladium. The formation mechanism of catalytic hydrogen wave is BC process coupled with chemisorption.

콘크리트 덧씌우기 전후 비교조사에 따른 덧씌우기공법의 지지력 및 하중전달 특성 연구

권순민,서영찬 漢陽大學校 工學技術硏究所 1997 工學技術論文集 Vol.6 No.1

A 290m 2-lane experimental concrete overlay was constructed in 88 Express Highway to investigate it's feasibility in Korea. The test section consists of both bonded and unbonded type overlays. Pavement condition of the existing slab was surveyed before overlay, and construction feasibility of concrete overlay was checked during construction. After overlay, delamination, crack, deflection(using FWD), and load transfer at various temperature conditions have been measured periodically. Findings from the study can be summarized as follows. (1) The overlays performed successfully during at least 1 year after construction, (2) Overlay reduced deflection by 47% in bonded overlay section and by 57% in unbonded overlay section, (3) Unbonded overlay showed better load transfer than bonded overlay, (4) Joints transfer dowel bar showed better load transfer than those without dowel bar, and (5) Load transfer efficiency varied with temperature conditions.

중대산업사고 예방을 위한 종합위험관리체제(IRMS) 구축에 관한 연구

권혁면,성대현,김재현,임대식,김기영,편무욱,문일,고재욱,이영순,윤인섭 한국안전학회 2003 한국안전학회지 Vol.18 No.3

The Process Safety Management (PSM) by the Law of Industry, Safety and Health has been performed for preventing major accidents of chemical plants since 1996. In terms of preventing chemical accidents more precisely, it is essential to develop a tool for quantitative risk assessment. For this, KOSHA (Korea Occupational Safety and Health Agency) developed an Integrated Risk Management System (IRMS) . The system is designed to assimilate data on chemical plant hazards from external database, to integrate these data with location information (topographic and demographic), and to make them user-friendly accessible. The system consists of several main functions: display of five major Korean petrochemical complex layout, display of equipment layout with its information utilizing the external database, zonation of the hazard effected area with consequence analyses, the most probable accident scenario generation, accident/incident database and calculation of frequency of accident using equipment reliability database, etc. The highlight of IRMS is to provide the risk contours using GIS(Geographical Information System) technology. IRMS is intended to manage hazardous installation more systematically and effectively, to reduce the number of accident remarkably, further minimizing production loss in the plant. The system is now under application to about 500 PSM sites as well as and emergency authorities in Korea by KOSHA (Korea Occupational Safety and Health Agency)

재해성 요추 추간판 탈출증의 역학 및 임상적 연구 : 비재해성 추간판 탈출증과 비교분석

권순용,이승구,장일석,김지홍,임영 대한산업의학회 2000 대한직업환경의학회지 Vol.12 No.2

Objectives : The purpose of study was to define the clinical and epidemiological factors of HNP and to provide the meaningful sources for establishing a prognosis and a rationale for clinical management of occupational low back problem. Methods : This study was performed at eight branch hospitals of Catholic University of Korea and several governmental hospitals for occupational disorders around the Kyunggi province of Korea since Jan. 1985. We analyzed the several factors about lumbar HNP through comparative study of the hospital admission series of each 200 patients in both occupation- and nonoccupation related, subjected to epidemiologic and clinical investigation, respectively. Results : 1. Mean age of occupational HNP was younger (30.9±8.8) than non-occupational HNP (35.2±10.5) (p〈0.05). 2. The duration of clinical symptom before admission was longer in non-occupational HNP(19.9±22.8 Mo.) than in occupational HNP(6.9±12.4 Mo.) (p〈0.05). 3. The symptomatic attack before admission was more frequent in non-occupational HNP(3.7±1.9) than in occupational HNP(2.5±0.9) (p(0.05) 4. There were no significant differences in physical findings between two groups, except for low rate (63%) of straight leg raising test (SLR) limitation in occupational HNP compared to non-occupational HNP(83%) (p〈0.05). 5. Even though The main reason for operative intervention was a failure of conservative treatment in both groups (p〈0.05), extruded subligamentous type was predominant(50%) in occupational HNP (p〈0.05), whereas extruded transligamentous type occupied major portion (67.8%) in non-occupational HNP (p〈0.05). Conclusion : The clinical results were poor in occupational HNP in both conservative and operative management groups, compared to non-occupational HNP (p〈0.05) and mean durations admission and re-admission rate was higher in occupational HNP, compared to non-occupational HNP (p〈0.05).