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).

일부 종합병원 간호사들의 요통 유병상태에 관한 조사연구

권순태,이동배,이태용 충남대학교 의과대학 지역사회의학연구소 1991 충남의대잡지 Vol.18 No.2

A questionaire survey was conducted on 482 hospital nurses in Taejeon City to investigate the prevalence & epidemiolgical characteristics of work related LBP during past six mouths. The results obtained were as follows. 1. Overall 6 months prevalence rate of LBP was 49.5% & mean duration of LBP were 10.8 days. 2. 6 months prevalence rate of LBP was the highest among nurses of care unit with 61.4% & mean duration of LBP were significantly longer among nurses of care unit with 17.7 days than other department workers. 3. 6 months prevalence rate of LBP was significantly higher among groups lifting frequency/day more than 20 with 62.9% than below 20 group with 46.1% (P<0.01). 4. Back injury rate was 27.4% with lumbar sprain with 19.5%, contusion with 7.5%. 5. Back injury rate was significantly higher among care-unit workers with 32.4% (P<0.05) than other department workers. 6. 10.8% of workers with LBP experienced absenteeism due to LBP. Among the injured, only 39.6% ran been treated.

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.

전주,익산지역 산업단지 악취 및 유해대기오염물질 발생원 조사

권영호,박성순,양고수 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2002 工學硏究 Vol.33 No.-

VOCs (Volatile Organic Compounds) have been produced commercially and used for many purposes in the chemical industry including the manufacture of herbicides, plastics, and solvent. Their emissions affect the change of climate, the growth and decay of plants, and the health of human beings and animals. Therefore it is necessary to limit and control of VOC emission. There are various removal technologies of VOCs, such as catalystic oxidation, biofiltration, Adsorption, Thermal oxidation and Menbrane separation. In this study, we examined both source and components of odor and VOC pollutants emitted from Jeonju and Iksan industrial Area. According to the results, the main VOCs used in the two industrial Area were benzene, toluene, chloroform, methanol, methylene chloride, xylene, ethyl ethyl ketone etc. Especially, hydrogen peroxide and methanol were extremely used in these complex. The regulation of VOC will be more strict within near future. Therefore, this research work will be applicable removal efficiency of VOC emitted from Jeonju and Iksan industrial Area as a fundamental data.

거대 난소 종양의 염전 1예

김미영,이해혁,유애리,박정희,이임순,정수호,고은석,레앙소팥,배동한,김태희,이권해 순천향의학연구소 2008 Journal of Soonchunhyang Medical Science Vol.14 No.1

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분동의 질량측정시스템에 관한 연구

권순규,정광영 공주대학교 생산기술연구소 2002 論文集 Vol.10 No.-

This paper presents a study on the mass measurement system which consists of a balance, weight exchangers, a step motor and a motor controller. Each weight exchanger adopts a ladder type pan in order to reduce the eccentric error. Using the suggested system, the measured standard deviation and measurement time have been improved compared to the manual mass measurement system.

해마 theta리듬과 pyramidal neuron의 세포내 특성과의 상관관계

권오흥,조진화,남순현,김현정,최병주,김영진,이만기 大韓小兒齒科學會 1998 大韓小兒齒科學會誌 Vol.25 No.4

Eledctrophysiological phenomena of pyramidal cells in the CAI area of the dorsal hippocampus were recorded from and filled with neurobiotin in anesthetized rats. The electropharmacological properties of membrane as well as the cellular-synaptic generation of rhythmic slow activity (theta)were examined. The intracellular response characteristics of these pyramidal cells were distinctly different from responses of inteneurons. Pyramidal cells had a high resting membrane potential, a low input resistance, and a large amplitude action potential. A afterhyperpolarization was followed a single action potential. Most of pyramidal cells did not display a spontaneous firing. Pyramidal cells displayed weak inward rectification and anodal break excitation. The slope of the frequency-current relation was 53.4 Hz/nA for the first interspike interval and 15.9 Hz/nA for the last intervals, suggesting the presence of spike frequency adaptation. Neurobiotin-filled neurons showed pyramidal morphology. Cells were generally bipolar dendritc processes ramifying in stratum lacunosum-moleculare, radiatum, and oriens. Commissural stimulation discharged pyramidal cells, followed by excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs). The frequency of theat-related membrane potential oscillation was voltage-independent in pyramidal neurons. At strong depolarization levels (less than 30 mV) pyramidal cells emitted sodium spike oscillation, phase-locked to theta. The observations provide direct evidence that theta-related rhythmic hyperpolarization of principal cells is brought by the rhythmically discharging interneurons. Furthermore, the findings in which interneurons were also paced by rhythmic inhibitory postsynaptic potentials during theta suggest that they were periodically hyperpolarized by their GABAergic septal afferents.

은미소전극과 매달린 수은방울전극에서 간단한 할로겐화알킬의 환원현상에 대하여

권영순 가톨릭대학교 자연과학연구소 1990 자연과학논문집 Vol.11 No.-

RX(R=CH₃ CH₂-, CH₃(CH₂)₂-, CH₃(CH₂)₃-, X=I^(-), Br^(-))의 환원은 은전극과 수은전극에서 모두 비가역적이며 사슬의 길이가 길수록 환원은 더 어려워진다. 은전극에서 RI의 환원봉우리전류는 cycle의 횟수가 증가함에 따라 커지게 되며 RBr의 환원전류는 RI의 반대현상을 나타내게 된다. 그러나 수은전극에서는 RI와 RBr 모두 cycle에 관계없이 일정한 순환전압전류곡선을 얻게 되는데 특이한 현상은 RI의 경우 reverse sweep에서 전도된 파가 나타난다. 이것은 RBr의 환원과는 달리 RI는 수은전극에서 radical을 거쳐 환원된다는 증거가 된다. The reductions of simple alkyl halides on silver microelectrode and hanging mercury drop electrode(HMDE) are irreversible. In straight clain molecules, the reduction becomes more difficult with increasing chain length. The different cyclic voltamograms of RI and RBr on silver electrode are obtained. The reduction peak of RI is larger on later cycles than on the former and the reduction current of RBr is smaller on later cycles than on the first. But the cyclic voltamograms of RX on HMDE are exactly constant on subsequent cycles and reproducibility is very good unlike on silver microelectrode. And the unusual phenomenon of RI on HMDE is the inverted peak on anodic sweep in cyclic voltammetry. It shows that the adsorbed radical intermediate is present on the reduction pathway of RI on HMDE.