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      • 麥類條播機用 上向切削 로터리의 碎土性과 所要動力에 關한 硏究(Ⅰ)

        崔圭洪,洪顯裕,李承奇 建國大學校 附設 農業資源開發硏究所 1993 農資源開發論集 Vol.18 No.-

        본 시험은 麥類畦立細條播機 逆回轉 로터리 作業時 耕深을 16cm로 고정하고 耕耘 피치 및 토양수분 차이가 PTO軸의 토크와 所要動力 排水溝의 형상 및 쇄토율 등에 미치는 영향을 구명하기 위하여 벼 수확을 마치고 벼그루가 남아 있는 埴壤土의 논에서 시험을 실시하였으며 주요 결과는 다음과 같다. 1) PTO軸의 平均토크 및 最大토크는 토양수분에 따라 차이는 있지만 逆回轉 로터리의 耕耘 토크는 耕耘 피치 6cm이하에서는 耕耘 피치 증가에 따라 직선적으로 증가하지만 耕耘 피치 6cm이상에서는 耕耘 피치 증가에 관계없이 거의 일정한 경향이었다. 2) 作業速度와 排水溝 殘存흙 및 覆土狀態는 逆回轉 로터리의 주행속도가 느릴수록 또 PTO回轉速度가 빠를수록 양호하여 주행속도 1단 PTO 3단에서 가장 좋게 나타났다. 3) 쇄토율은 耕耘 피치가 증가할수록 또 토양수분이 높을수록 쇄토율은 떨어지는 경향이었으며, 충분한 碎土程度를 얻기 위하여는 耕耘 피치를 3cm이하로 하고 가능한 토양수분 함량 31.7%(d.b) 이하에서 작업하는 것이 좋을 것으로 판단되었다. 4) PTO軸의 所要動力은 작업속도 1∼4단 로터리 變速段數 1∼3段에서의 PTO軸 所要動力은 토양수분 38.0%(d.b)일 때 5.1∼14.5ps, 35.5%(d.b)의 경우 7.9∼14.2ps, 31.7%(d.b)일 때는 4.6∼12.7ps로 나타나 토양수분이 증가할수록 소용동력은 증가하다가 다시 감소하는 경향이었다. 5) 覆土狀態는 耕耘 피치가 적을수록 양호하여 주행속도 1단 PTO 3단의 경우 가장 좋았으며, 작업능률면을 고려할 때 排水溝 程度, 覆土狀態, 所要動力 및 作業能率 등을 고려할 때 畦立 로터리 파종작업시 PTO變速段數는 3단으로 하고 주행단수는 토양수분 함량 31.7%(d.b) 내외에서는 3단, 토양수분함량 35.5%(d.b) 내외에서는 2단, 토양수분 함량 38.0%(d.b) 이상에서는 1단으로 작업하여야 할 것으로 판단된다. This study was carried out to investigate the soil pulverization rate and power requirement of up-cut rotary of wheat and barley drill seeder for tractor by tilling pitch and soil moisture content. The experiment was conducted in the paddy field of clay roam remaining stem of paddy rice after harvesting. The results are summarized as follows: 1) Average and maximum torque of PTO shaft was increased in proportion with tilling pitch in less than 6cm, but was apt to definite over than 6cm of tilling pitch. 2) The working speed, status of remaining and covering soil in drainage was good in proportion with decrease the travelling speed of up-cut rotary and increae the revolutions per minute. Therefore, the working status in drainage was best in forward first gear and PTO third stage. 3) The soil pulverization rate was decreased according to increase the tilling pitch and soil moisture content. It was concluded that tilling work in 31.7 percent of soil moisture content and less than 3cm of tilling pitch would be good. 4) The power requirement of PTO shaft by soil moisture content were 5.2∼14,5ps in 38.0 percent, 7.9∼14.2ps in 35.1 percent and 4.6∼12.7ps in 31.7 percent soil moisture content. So the power requirement of PTO shaft was apt to increase in proportion with soil moisture content the first and decrease the last. 5) The status of soil covering was good in forward first gear and PTO third stage. When it was considered the status of drainage, covering the soil and power requirement in working performance, it was concluded that the PTO stage would be third and working speed would be forward third gear in 31.7 percent, forward second gear in 35.5 percent and forward first gear in 38.0 percent of moisture content.

      • Mycophenolic Acid가 PDGF에 의해 증식 유도된 흰쥐 혈관평활근 세포에서 NAD(P)H Oxidase, 세포내 활성산소족 및 Mitogen-activated Protein Kinases에 미치는 영향

        박제현,하헌주,김명수,허규하,김유선 이화여자대학교 약학연구소 2004 藥學硏究論文集 Vol.- No.14

        Background: Vascular smooth muscle cell (VSMC) proliferation plays an important role in the development and progression of chronic allograft vasculopathy as in atherosclerosis. We already reported that mycophenolic acid (MPA) inhibited VSMC proliferation, cellular reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPK) in human VSMCs. In this study, we examined further molecular mechanisms involved in the anti-proliferative effect of MPA in rat VSMCs. Methods: Primary rat VSMCs were stimulated with PDGF-BB 10 ng/mL in the presence or absence of MPA and various kinds of cell signaling inhibitors. Cell proliferation was assessed by [H³]-thymidine incorporation, NAD(P)H oxidase subunits mRNA expression by RT-PCR, dichlorofluorescein-sensitive cellular ROS by FACS, and the activation of PDGF receptor-β (Tyr 751), racl, and MAPK by Western blot analysis. Results: PDGF increased cell proliferation and cellular ROS, activation of PDGF receptor-β (Tyr 751), racl, expression of p22phox and MOX1 mRNA, ERK 1/2, and p38 MAPK, compared to control. MPA inhibited up-regulation of racl phosphorylation, p22phox and MOX1 mRNA expression, cellular ROS, and phosphorylation of ERK 1/2 and p38 MAPK. However, MPA did not affect PDGF receptor-β (Tyr 751) activation. Wortmannin, diphenyleniodonium (DPI), trolox, and NAC, each inhibited PDGF-induced ERK 1/2 and p38 MAPK activation. PD98059 and p38 MAPK inhibitor also inhibited PDGF-induced cell proliferation. Conclusion: These results suggest that MPA inhibits PDGF-induced VSMC proliferation through inhibiting NAD(P)H oxidase-dependent cellular ROS leading to ERK 1/2 and p38 MAPK activation. 배경 : 혈관평활근 세포의 증식은 장기이식 후 발생하는 혈관경화증이나 동맥경화증의 발생과 진행에 중요한 역할을 한다. Mycophenolic acid (MPA)는 강력한 면역억제제로서 혈관평활근 세포의 증식도 억제한다. 본 연구는 사람의 혈관평활근 세포에서 MPK가 세포증식에 관여하는 신호전달계인 활성산소족과 mitogen-activated protein kinases(MAPK) 활성화를 억제하는 기존의 연구결과를 바탕으로, PDGF에 의해 증식 유도된 흰쥐 혈관평활근 세포에서 MPA가 세포의 증식을 억제하는 기전을 검색하였다. 방법 : 일차 배양한 흰쥐 혈관평활근 세포를 PDGF-BB 10 ng/mL로 자극하였고, MPA를 비롯한 여러 종류의 신호전달 억제제는 PDGF를 투여하기 1시간 전에 투여하였다. 세포증식은 [H³]-thymidine incorporation으로, NAD(P)H oxidase subunit의 mRNA 표현은 RT-PCR로, dichlorofluorescein에 민감한 세포내 활성산소족은 FACS 방법으로, 그리고 PDGF 수용체-β (Tyr 751), racl 및 MARK 활성하는 Western blot으로 각각 분석하였다. 결과 : PDGF는 PDGF 수용체-β (Tyr 751)의 활성화 및 NAD(P)H oxidase subunit 중 racl의 활성화와 p22phox와 MOX1의 mRNA 표현을 대조군에 비하여 유의하게 증가시켰다. MPA는 PDGF 수용체의 활성화에는 영향을 주지 않았으나, racl의 활성화, p22phox와 MOX1의 mRNA 표현의 상향 조절, 세포내 활성산소족, 그리고 ERK 1/2와 p38 MAPK의 활의한 EFK 1/2와 p38 MAPK 활성화와 세포 증식을 억제하였다. PD98059와 p38 MAPK 억제제는 PDGF에 의한 혈관평활근 세포의 증식을 억제하였다. 결론 : 본 연구결과는 MPA가 NAD(P)H oxidase를 억제함으로써 세포내 활성산소족 생산과, MAPK 활성화를 억제함으로써 PDGF에 의하여 유도되는 혈관평활근 세포의 증식을 억제함을 시사하였다.

      • 안지오텐신 변환효소 억제제와 안지오텐신 II 수용체 차단제 투여 후 발생한 급성 신부전과 폐부종으로 전원된 선천성 단일신 환자의 치료 1예

        백두현,김경진,홍성철,강석형,송하응,김혜인,김수현,오현정,강혜원,김서우,유민아,류동열,최규복,강덕희 이화여자대학교 의과대학 2010 EMJ (Ewha medical journal) Vol.33 No.1

        Blockers of renin-angiotensin system(RAS) including ACE inhibitor or ARB are one of the most frequently prescribed medications for the treatment of hypertension, heart failure and proteinuria. One of the major side effects of these RAS blockers is the deterioration of renal function, mainly due to a reduction of intraglomerular pressure. Therefore, close monitoring of renal function is recommended when RAS blockers are initially prescribed, especially for the patients with impaired renal function. We report a patient who was transferred to our hospital due to the sudden development of oliguria and dyspnea after treatment for hypertension with ACEi and ARB. She was finally diagnosed as RAS blocker-induced acute renal failure with pulmonary edema complicated on congenital solitary kidney. After hemodialysis and conservative treatment, her renal function was recovered with maintenance of normal urine output. Conclusion:This case highlights the necessity of the functional and structural evaluation of kidney to prevent the serious complication such as acute renal failure before the administration of ACEi and/or ARB.

      • Mycophenolic Acid와 Rapamycin이 흰쥐 사구체 혈관간세포증식과 세포외기질 생성에 미치는 영향

        김명수,박제현,하헌주,허규하,서지연,김유선,김혜진,박기일 이화여자대학교 약학연구소 2004 藥學硏究論文集 Vol.- No.14

        Background: Excess proliferation and extracellular matrix (ECM) accumulation of mesenchymal cells such as vascular smooth muscle cells (VSMC) and glomerular mesangial cells cause chronic allograft nephropathy showing transplant vascular sclerosis and glomerulosclerosis. Mycophenolic acid (MPA) and rapamycin (RPM) are well known as strong inhibitors of VSMC proliferation, but their effects on the glomerular mesangial cells are not yet clearly understood. This study examined the effects of MPA or RPM on PDGF-induced proliferation and ECM accumulation in rat glomerular mesangial cells. Methods: Mesangial cells isolated from the glomeruli of Sprague-Dawley rats were cultured with DMEM containing 20% fetal bovine serum. Growth arrested and synchronized cells were administered with test drugs (MPA10 nM-10μM, RPM 0.1 nM-1μM) before the addition of PDGF 10 ng/mL. Cell proliferation was assessed by [³H]thymidine incorporation, collagen by [³H]proline incorporation, and fibronectin, ERK, and p38 MAPK by Western blot analysis. Results: PDGF increased mesangial cell proliferation by 4.64-fold. Compared to stimulated control, MPA above 500 nM and RPM above 10nM showed a significant inhibitory effect in a dose-dependent manner. The IC_(50) of MPA and RPM against PDGF-induced mesangial cell proliferation were around 500 nM and 100 nM, respectively. The collagen synthesis was also inhibited by MPA and RPM, but the fibronectin secretion was inhibited by MPA alone. The proliferation of mesangial cell correlated with activation of ERK and. p38 MAPK. MPA, but not RPM, inhibited ERK and p38 MAPK activation. Conclusion: This study demonstrated that MPA and RPM significantly inhibited PDGF-induced proliferation and ECM production in rat glomerular mesangial cells. The inhibitory effects of MPA, but not RPM, are correlated with ERK and p38 MAPK.

      • 장중첩증을 동반한 맹장 지방종 1예

        홍의실,나병규,김민옥,유일영,채지영,채희복,윤세진,이상전,송형근,박길선,정현용 충남대학교 의과대학 의학연구소 2002 충남의대잡지 Vol.29 No.2

        대장 지방종은 주로 우측 결장에 호발하고 특히 회맹판 부위와 맹장 부위에 호발한다. 또한 50~60대에 빈도가 높고 증상이 있는 환자에서 장중첩증이 높게는 40~50%에서 보고되고 있어 성인 장중첩증의 원인으로 중요한 비중을 차지한다. 특히 성인 장중첩증 및 장폐쇄의 중요 원인인 악성 종양과 임상 양상이 유사하여 감별진단이 중요하다. 저자들은 반복적인 복통을 주소로 내원한 환자에서 맹장의 4×5㎝의 점막하 지방종이 말단 회장부위와 반복적인 장중첩중이 발생했던 1례를 부분 절제술로 치료하여 양호한 임상 경과를 경험하였기에 문헌 고찰과 함께 보고하는 바이다. Lipomas are one of the most common benign nonepithelial tumors of the colon which are often detected incidentally by radiologic investigation or on operation. These tumors are usually without specific symptoms. Colonic lipomas occur most often in the right colon, particularly in the ileocecal valve and the cecum. Most patients are asymptomatic. but tumors larger than 2 cm tend to produce a change in bowel habit. abdominal pain. rectorrhagia and complications including luminal obstruction or intestinal intussusception. Diagnosis can be made by colonoscopy abdominal CT. MRI, or barium enema. We report a case of lipoma of the cecum that originated in the submucosa and presented as a intussusception in a 50-year-old woman with a brief review of the literature.

      • TiO₂를 이용한 프로필렌 가스의 광촉매 산화반응

        정대일,이동희,김용환,김현숙,이용균,박유미,최순규,김동현 동아대학교 환경문제연구소 2001 硏究報告 Vol.24 No.1

        Photocatalyzed degradation of propylene gas was carried out over precoated titanium dioxide(anatase) illuminated W light in a flow reactor. photocatalytic oxidation of propylene gas indicated high conversion rates (78.0%) to CO₂ gas. And photocatalytic oxidation of gas according to a fold, twofold, and threefold of titanium dioxide(anatase) respectively gave high conversion rate. The longer reaction time was, the higher conversion rate to CO₂ gas showed.

      • KCI등재
      • TiO₂를 이용한 아세틸렌 가스의 광촉매 산화반응

        정대일,김성엽,이도훈,이용균,박유미,최순규,김동현 동아대학교 환경문제연구소 2000 硏究報告 Vol.23 No.1

        Photocatalyzed degradation of acetylene gas was carried out over precoated titanium dioxide(anatase) illuminated UV light in a flow reactor. photocatalytic oxidation of acetylene gas indicated high conversion rates (78.0%) to CO₂gas. And photocatalytic oxidation of gas according to a fold, twofold, and threefold of titanium dioxide(anatase) respectively gave high conversion rates. The longer reaction time was, the higher conversion rate to CO₂ gas showed.

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