" The Korean Journal of Chemical Engineering " 게재 논문 요약 : Processabilities & Mechanical Properties of the Biodegradable LDPE / Modified Starch Blends

Young Jin Kim,Yong Man Lee,Hyang Mok Lee,O Ok Park 한국화학공학회 1994 NICE Vol.12 No.5

N/A An investigation of the biodegradable polymers based on starch has been accomplished. Starch needs to be modified before blending with low density polyethylene(LDPE) because of its hydrophilicity. Three kinds of modification methods were applied to obtain the compatibility to starch-LDPE blends. The first one was the esterification of the hydroxyl group of starch with acetic anhydride. The second was the copolymerization of actylonitrile and styrene onto starch. The last was the esterification reaction of the hydroxyl group of starch with three kinds of ionomers. The tensile strength, % elongation, Young`s modulus, and shear viscosities of blends of the modified starch and LDPE were examined. Ionomer-treated starch showed better compatibility with LDPE to give better performances than other blends.

PROCESSABILITIES & MECHANICAL PROPERTIES OF THE BIODEGRADABLE LDPE/MODIFIED STARCH BLENDS

Kim, Young Jin,Lee, Yong Man,Lee, Hyang Mok,Park, O Ok 한국화학공학회 1994 Korean Journal of Chemical Engineering Vol.11 No.3

An investigation of the biodegradable polymers based on starch has been accomplished. Starch needs to be modified before blending with low density polyethylene (LDPE) because of its hydrophilicity. Three kinds of modification methods were applied to obtain the compatibility to starch-LDPE blends. The first one was the esterification of the hydroxyl group of starch with acetic anhydride. The second was the copolymerization of acrylonitrile and styrene onto starch. The last was the esterification reaction of the hydroxyl group of starch with three kinds of ionomers. The tensile strength, % elongation, Young's modulus, and shear viscosities of blends of the modified starch and LDPE were examined. Ionomer-treated starch showed better compatibility with LDPE to give better performances than other blends.

개에서 Chiari-like malformation에 의한 척수공동수증과 수두증의 발생 1례

신영지,박정희,김영실,최호정,이영원,정성목 忠南大學校 獸醫科大學 動物醫科學硏究所 2005 動物醫科學硏究誌 Vol.13 No.-

A 2.5㎏, 11-year old, intact female mixed breed dog with 1 year history of sporadic seizure was referred to the Veterinary Medical Teaching Hospital of Chungnam National University. There were no significant finding in CBC and serum chemistry. Based on X-ray, CT scan and MRI, it was diagnosed as syringohydromyelia and hydrocephalus caused by Chiari-like mlaformation. Prednisolone, furosemide and phenobarbital was administered orally. Depend on the number and severity of seizure, the dose of phenobarbital was adjusted. Seizure episode was reduced.

Rat의 복강내에 투여한 5-fluorouracil-polyglycolic acid 제형이 장기에 미치는 영향에 관한 연구

강대영,송규상,최정목,노승무,정경수,오정연,김진향,양준묵,최선웅,이진호,조준식,민병무,김용백,김창식,박근성,김승영,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

For more effective intraperitoneal chemotherapy, the authers made 5-fluorouracil-polyglycolic acid composite disks(FU-PGA disks) with 5-fluorouracil and polyglycolic acid, a biodegradable polymer. We inserted the FU-PGA disk into the peritoneal cavites of Sprague-Dawley male rats, the control and three experimental groups; one FU-PGA disk insert group(300mg/kg), two FU-PGA disk insert group(600mg/kg), and three FU-PGA disk insert group(900mg/kg). The control group received a similar number of PGA disk inserts. A pharmacokinetic study was performed to measure the 5-fluorouracil concentration in the peritoneal fluid, blood, and tissues(liver, kidney and heart) at 24 hours, 72hours and 168 hours after insertion of the FU-PGA disk. Light and electron microscopic studies were done. The results were as follows: 1) The number of white blood cells and platelets decreased after FU-PGA insertion. The degree was proportional to the duration and amounts inserted. The change in the number of red blood cells varied slightly. 2) Light microscopically, slight changes were noted at 168 hours in the 3 disk insert group (900mg/kg). Mild fatty change and hepatocyte degeneration around the central veins of the liver were noted, with vacuolar degeneration in the proximal convoluted tubules of the kidney. 3) Electron microscopically,the liver showed focal increases of lipid droplets in the hepatocytes, and irregular nuclear membrane with focal nucleolar segregation of the fibrillar and granular elements. Also the double membranous structure of the hepatocytes and Kupffer cells was widened with bleb formation. The kidney showed wide separation of the nuclear double membrane in the proximal convoluted tubular cells and mesangial cells, with vacuolation and myelin figure formation in the mitochondria of the proximal convoluted tubular cells, at 72 hours and 168 hours in the 2 to 3 FU-PGA insert groups. The heart showed focal loss of cristae,vacuolation and myelin figure formation in the mitochondria of the 2 to 3 FU-PGA insert groups. In conclusion, despite the large amont of FU-PGA inserted, the histopathological changes in the liver, kidney and heart were slight, and consonant with the very low amount of 5-fluorouracil concentrations detected in the liver, kidney and heart. The above results suggest that the FU-PGA composite can serve as a new device for releasing drugs in a controlled manner and easily targeted to intraperitoneal organs. This device can improve the efficacy of intraperitoneal chemotherapy for gastric cancer.

백서의 복강내에 투여한 Mitomycin-C-Polyglycolic acid 제형이 장기에 미치는 영향에 관한 연구

송규상,강대영,최정목,노승무,정경수,오정연,김진향,양준목,최선웅,이진호,조준식,민병무,김용백,김창식,박근성,김승영,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

To evaluate the in-vivo effects of mitomycin-C-polyglycolic acid composite(MMC-PGA) the disk: shaped composite were implanted into the peritoneal cavity of the Sprague-Dawley rats. The pathologic changes were examined at various time points up to 12 weeks. Initially the soft tissue around the inserted disks showed capillary congestion at 3 days. Inflammatory infiltrates with foreign body giant cells appeared from the 2nd week and reached peak response at 6-8 weeks. These reaction diminished prominently at 12 weeks. No specific pathologic change was found in the liver, the kidneys, and the heart. The above results suggest that the MMC-PGA composite can serve as a new device for intraperitoneal chemotherapy of various types of cancers.

The role of FGF-2 in smoke-induced emphysema and the therapeutic potential of recombinant FGF-2 in patients with COPD

Kim, You-Sun,Hong, Goohyeon,Kim, Doh Hyung,Kim, Young Min,Kim, Yoon-Keun,Oh, Yeon-Mok,Jee, Young-Koo Nature Publishing Group UK 2018 Experimental and molecular medicine Vol.50 No.11

<▼1><P>Although the positive effects of recombinant fibroblast growth factor-2 (rFGF-2) in chronic obstructive pulmonary disease (COPD) have been implicated in previous studies, knowledge of its role in COPD remains limited. The mechanism of FGF2 in a COPD mouse model and the therapeutic potential of rFGF-2 were investigated in COPD. The mechanism and protective effects of rFGF-2 were evaluated in cigarette smoke-exposed or elastase-induced COPD animal models. Inflammation was assessed in alveolar cells and lung tissues from mice. FGF-2 was decreased in the lungs of cigarette smoke-exposed mice. Intranasal use of rFGF-2 significantly reduced macrophage-dominant inflammation and alveolar destruction in the lungs. In the elastase-induced emphysema model, rFGF-2 improved regeneration of the lungs. In humans, plasma FGF-2 was decreased significantly in COPD compared with normal subjects (10 subjects, <I>P</I> <I>=</I> 0.037). The safety and efficacy of inhaled rFGF-2 use was examined in COPD patients, along with changes in respiratory symptoms and pulmonary function. A 2-week treatment with inhaled rFGF-2 in COPD (<I>n</I> = 6) resulted in significantly improved respiratory symptoms compared with baseline levels (<I>P</I> <I><</I> 0.05); however, the results were not significant compared with the placebo. The pulmonary function test results of COPD improved numerically compared with those in the placebo, but the difference was not statistically significant. No serious adverse events occurred during treatment with inhaled rFGF-2. The loss of FGF-2 production is an important mechanism in the development of COPD. Inhaling rFGF-2 may be a new therapeutic option for patients with COPD because rFGF-2 decreases inflammation in lungs exposed to cigarette smoke.</P></▼1><▼2><P><B>Lung disease: Inhaling a protein might help</B></P><P>Studies on the role of the protein ‘fibroblast growth factor-2’ (FGF-2) in chronic obstructive pulmonary disease (COPD) suggest that inhaled FGF-2 could help treat the emphysema linked to smoking. Researchers in South Korea led by Young-Koo Jee at Dankook University, Cheonan, and Yeon-Mok Oh at the University of Ulsan, Seoul, studied the role of the reduced FGF-2 levels found in mice with lung inflammation caused by exposure to cigarette smoke. They also uncovered details of a protective effect of inhaled FGF-2, identifying specific cellular and lung structure changes attributed to the administered FGF-2. Reduced FGF-2 levels were also found in patients with COPD. Initial trials revealed some improvement in patients treated with FGF-2, but not at a statistically significant level. Nevertheless, the authors suggest their results justify further investigation of the protein’s therapeutic potential.</P></▼2>

이산화질소, 암모니아 및 수분의 기상반응에 의한 이산화질소 제거 거동에 관한 연구

목영선,장경룡,박태성,김경숙,남인식 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.1

암모니아 첨가 저혼 플라즈마 공정이나 전자빔 공정에서 NO의 산화반응을 통해 생성되는 NO_2를 효과적으로 제거하기 위한 조건을 도출하기 위하여, 문헌의 반응속도에 기초한 반응기 모델링을 통해 NO_2 저감에 미치는 여러 가지 운전변수의 영향을 살펴보았다. 본 연구에서 운전변수로 선정한 것은 수분함량, 초기 NO_2 농도, 반응온도 그리고 암모니아 농도이며, 각각의 운전변수에 대한 적정 범위를 결정하였다. NO_2를 효율적으로 제거하기 위해서는 배기가스의 수분함량이 4-6%(v/v)이상은 되어야 하나, 수분함량을 더 증가시키는 것은 큰 이득이 없는 것으로 나타났다. 초기 NO_2 농도가 100ppm 이하로 작을 때는 원하는 제거효율을 달성에 필요한 체류시간이 급격히 증가하며, 반응온도는 낮을수록 NO_2제거에 유리한 것으로 나타났다. NO_2 저감 속도는 암모니아 농도이며, 각각의 운전변수에 대한 적정 범위를 결정하였다. NO_2를 효율적으로 제거하기 위해서는 배기가스의 수분함량이 4-6%(v/v)이상은 되어야 하나, 수분함량을 더 증가시키는 것은 큰 이득이 없는 것으로 나타났다. 초기 NO_2 농도가 100ppm 이하로 작을 때는 원하는 제거효율 달성에 필요한 체류시간이 급격히 증가하며, 반응온도는 낮을수록 NO_2 제거에 유리한 것으로 나타났다. NO_2 저감 속도는 암모니아의 농도에 크게 의존하지 않는 것으로 평가되었다. This study reports a simple reactor modeling utilizing chemical kinetic data of the gas phase reaction between nitrogen dioxide, ammonia and water vapor in order to estimate the influences of several operating variables on the removal of NO_2 which is generated from NO by the oxidation process in a non-thermal plasma reactor or an electron-beam irradiation reactor. The operating variables chosen are water vapro content, initial concentration of NO_2, reaction temperature and ammonia concentration and the appropriate ranges of such variables were suggested. The gas phase reaction for the removal of NO_2 takes place effectively at the water vapor content higher than 4-6%(v/v), but further increase in the water vapor content does not significantly enhance the removal. The residence of NO_2 is less than 100ppm. Since the removal rate of NO_2 is in inverse proportion to the reaction temperature, lower temperature is favorable to promote the reaction. The effect of ammonia concentration on the removal of NO_2 was estimated to be negligible.

이산화질소, 암모니아 및 수분의 기상반응에 의한 암모늄염 생성 거동에 관한 연구

목영선,이호원,현영진 제주대학교 해양과환경연구소 2001 해양과환경연구소 연구논문집 Vol.25 No.-

This study investigates the kinetics of the gas phase reaction between nitrogen dioxide, ammonia and water vapor, and presents the appropriate ranges of the process variables such as initial NO_2 concentration, absolute humidity and reaction temperature for the effective removal of nitrogen dioxide. According to the kinetic calculations, the gas phase reaction for the removal of NO_2 takes effectively place at the water vapor content higher than 4-6 %(v/v), but further increase in the water vapor content does not significantly enhance the removal. The residence time required to achieve a desired removal efficiency of NO_2 was found to increase with the decrease in its initial concentration. Especially, the residence time required rapidly increases when the initial concentration of NO_2 is less than 100 ppm. The removal rate of NO_2 is in inverse proportion to the reaction temperature, i.e., lower temperature is favorable to promote the removal rate. The results obtained in this study may be useful for the determination of the optimal values of the process variables in non-thermal plasma technology for the removal of nitrogen oxides.

極小曲面의 安定性에 관하여

목영부 건국대학교 1987 論文集 Vol.25 No.1

Let M be a minimal surface in E3 and D be a geodesic disc of radius r, at a center p. If either of the following conditions satisfies, then D is unstable. (i) There exists 0<ξ<ρ such that ◁수식삽입▷ (원문을 참조하세요) (ii) Vol(D) > 4/3πρ2 In this note, we prove the following theorem using the above conditions. [Theorem] Complete simply connected stable minimal surface is place, where surface M is stable provided arbitrary finite domain of surface M is stable.

매쉬-심 용접 판재의 성형 한계

김형목,허영무,양대호,서대교 기계기술연구소 1999 성균관대학교 논문집 기계기술편 Vol.1 No.1

This paper describes experimental investigation on the forming limit for mash-seam welded sheets. The uniaxial tensile test was conducted to evaluate the mechanical properties of weld bead. Experimental forming limit diagrams were investigated for the different thicknesses and properties of welded sheets.