좌심실비후 환자에서 베타차단제의 급중단이 임상증상 및 좌심기능에 미치는 영향

황종현,김영태,배용학,임현주,조용근,채성철,전재은,박의현 慶北大學校 醫科大學 1997 慶北醫大誌 Vol.38 No.1

목적 : 베타 차단제와 칼슘 길항제의 장기투여로 안정상태에 있는 비후형 심근증이나 고혈압성좌심실비후 환자에서 이들 약제를 갑자기 중단하였을 때 혈역학, 심기능 및 임상상에 미치는 영향을 알아보기 위하여 본 연구를 시행하였다. 대상 및 방법 : 경북대학교 병원 순환기내과에서 통원치료중인 비후형 심근중 환자 5명과 심한좌심실비후를 동반한 고혈압 환자 6명(남자 6명, 여자 5명)을 대상으로 장기투여 중이던 베타 차단제와 칼슘 길항제를 최소 5일 중단한 후 임상증상, 혈압 및 심박수의 변동, 그리고 투약중지 전후에 도플러 심초음파도를 기록하여 좌심실내경, 벽두께, 좌심실근량, 구혈율 및 승모판혈류속도곡선의 변화를 관찰하였다. 결과 : 1) 약물치료 중단 후, 베타차단제의 경우 9명 중 6명에서, 그리고 칼슘길항제 및 디소피라미드를 복용하던 각 1명, 도합 7명의 환자에서 심계항진, 호흡곤란의 악화, 흉통이 관찰되었고, 심계항진을 호소한 1예에서는 심방세동이 재발되었다. 2) 혈압, 심박수, 확장말기 및 수축말기 좌심실내경, 심실중격 및 심실후벽 두께, 좌심실근량 및 구혈을 모두는 치료약물 중단 전후에 다소 변화하였으나 유의하지 않았다. 3) E파 최고속도와 E파 시간속도적분은 약물투여 중단 전후에 유의한 변화는 없었으나, A파 최고속도와 A파 시간속도적분은 중단 후에 각각 유의하게 증가하였으며(both P<0.01), E/A 최고속도비와 E/A 시간속도적분비는 각각 유의하게 감소하였다(both P<0.01). 한편, E파 감속시간, 등용이완시간 그리고 A-Ar 간격[A파의 최고점에서 A reversal(Ar)파의 최저점간의 시간] 모두는 중단 후 유의한 변화가 없었다. 1 결론 : 비후형 심근증 이나 고혈압성 좌심실비후 환자에서 장기투여중이던 베타 차단제와 칼슘길항제를 일시적으로 중단하였을 때 임상중상의 악화와 더불어 확장기 기능의 변화를 초래하였다. 따라서 약물치료로 비록 임상적으로 안정상태에 있더라도 치료를 갑자기 중단할 때는 주의해야 할 것으로 생각된다. Objectives : This study was done to evaluate the changes in clinical findings, hemodynamics and cardiac function after abrupt withdrawal of longterm beta-blockers and/or calcium channel blockers in hemodynamically stable patients with hypertrophic cardiomyopathy and left ventricular(LV) hypertrophy associated with hypertension. Methods : Eleven patients with hypertrophic cardiomyopathy(n=5) and LV hypertrophy associated with hypertension(n=6) were studied. Symptom assessment, blood pressure, electrocardiography and echocardiography including pulsed Doppler examination were obtained before and at least 5 days after abrupt cessation of beta-blockers and calcium antagonists. Results : 1) Deterioration in symptoms(i.e. palpitation, aggravation of dyspnea and chest pain) was observed in seven patients after abrupt withdrawal. 2) There were no significant changes in blood pressure, heart rate, end-systolic and end-diastolic LV dimensions, interventricular septal thickness, LV posterior wall thickness, LV mass, and ejection fraction before and after drug withdrawal. 3) Doppler time intervals and E wave peak-velocity and time velocity integral(TVI) were not significantly changed before and after drug withdrawal. But A wave peak-velocity and TVI after abrupt withdrawal were significantly increased(both p<0.01), and E/A peak-velocity ratio and TVI ratio were significantly decreased(both p<0.01). Conclusions : These findings suggest that temporary omission of beta blockers and calcium channel blockers develops deterioration in symptoms and LV diastolic dysfunction in hypertrophic cardiomyopathy and LV hypertrophy associated with hypertension. Physicians should avoid abrupt withdrawal of longterm beta blockers in LV hypertrophy.

탄소섬유 적층혼성부재의 계면수 변화에 따른 축 압궤 특성

서현경,박준우,양용준,황우채,양인영 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

알루미늄과 CFRP는 대표적인 경량화 재료이다. 알루미늄 부재는 안정적인 소성 변형에 의해 에너지를 흡수하며, CFRP 부재는 비강성과 비강도가 우수하고 불안정한 취성파괴로 인해 에너지를 흡수한다. 이러한 각각 알루미늄과 CFRP 부재의 압궤 특성을 기초로 두 재 료의 결합에 의해 서로의 장점에 대한 시너지 효과를 얻기 위해 혼성구조부재를 제작하였다. 본 연구에서는 알루미늄 부재의 외측을 CFRP로 강화시킨 혼성구조부채를 제작하여 CFRP의 계면수 변화에 따른 축 방향 준정적 압궤실험을 행하여 사각 및 원형 단변 모형의 혼성구조부재의 압궤 특성을 조사하였다. 실험 결과 혼성구조부재는 내부의 알루미늄 부재의 연성 성질 때문에 CFRP 부재의 불안정한 취성 파괴를 보완하여 비교적 안정적인 압궤 모드를 보였다. 하지만 혼성구조부재는 계면수 변화에 대해 에너지 흡수성과 압궤 모드는 별다른 영향을 보이지 않았다. The aluminum or CFRP is representative of light-weight materials. The aluminum tubes absorb energy by stable plastic deformation and the CFRP tubes absorbs energy by unstable brittle failure with higher specific strength and stiffness. Based on the respective collapse characteristics of aluminum and CFRP tubes, the aluminum CFRP compound tubes were manufactured to get a synergy effect when the aluminum CFRP tubes were combined with the advantages of each tube. This paper is to investigate the collapse characteristics of square or circular shaped aluminum CFRP compound tubes subjected to quasi-static axial collapse tests which were conducted by changing the stacking conditions. Test results showed that the collapse of the aluminum CFRP compound tubes complemented unstable brittle failure of the CFRP tube due to the ductile characteristics of the inner aluminum tube. It turned out that interlaminar numbers of aluminum CFRP compound tubes have no influence on the energy absorption and collapse modes of the tubes.

충격하중을 받는 Al 박육부재의 에너지흡수 제어특성

양용준,황우채,서현경,김정호,심재기,양인영 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

In this study, concerns the crashworthiness of the widely used vehicle structure, square thin-walled tubes, which are excellent on the point of the energy absorbing capacity. An experimental investigation was carried out to study the energy absorption characteristics of thin-walled square tubes subjected to dynamic crushing by axial loading to develop the optimum structural members. The impact velocity was tested in the rage 4.698~8.2m/s. To efficiently review the collapse characteristics of these sections, the simulation have been carried out using explicit FEM package, LS-DYNA. The solutions compared with results the impact collapse experiment. Here, the controller are introduced to improve and control the absorbed energy of thin-walled square tubes in this paper. To predict and control the energy absorption, we designed it in consideration to the it's influence, height, thickness, wide ratio in this study. When the controller used, the experimental results of crushing of square tubes controlled by the controller's elements showed a good candidate for a controllable energy absorption capability in impact axial crushing.

국가수준 학교평가제도의 법적 근거 및 정당성 고찰

鄭秀炫,黃浚盛 대한교육법학회 2002 敎育 法學 硏究 Vol.14 No.2

In the new society of 21st century, creativity should be emphasized in education. And autonomy and diversity are significantly important to cultivate creativity. In this respect, autonomy of the school and school-based management are very crucial in improving the quality of education. However, such autonomy requires accountability, and a schools accountability should be evaluated to improve the school system. Many countries are making diverse efforts to evaluate the quality of educational institutes and schools. School evaluation can be defined as a process in which activities being performed at a school site are examined and professional advices and support are provided. Therefore, school evaluation should redefine its objectives as enlargement of autonomy of a school, enhancement of excellence in education, improvement of efficiency in management, and greater accountability of schools. The purpose of this study is to present the legal basis and validity of school evaluation at a national level under modern public educational system and educational law. In the study, first of all, meaning and background of school evaluation at national level are investigated. In the second, the legal basis of school evaluation at a national level is analyzed, which is prescribed in The Elementary and Secondary Education Law(§9) and ordinance concerned. In the third, the relationship between citizens' educational right and nation's right of evaluation of each school is studies. The study concludes that school evaluation at a national level enhance the people's right to receive education, notwithstanding the possibility of dispute among individuals concerned with public educational system.

성견 절치에서 수직 골결손 형성후 함입이동시 치주조직의 반응

박양수,김영준,최홍란,황현식 전남대학교 치과대학 2000 전남치대논문집 Vol.12 No.1

The present study was performed to investigate the periodontal response following orthodontic intrusion of teeth with vertical bony defect produced by periodontal disease. Vertical bony defect and periodontal disease were produced adjacent to the both maxillary second lateral incisors in four adult dogs, weighing 20kg or more. Four weeks later, a flap operation was performed to eliminate inflammation and a reference notch was made on the root surface at the level of bottom of each defect. Two weeks after periodontal surgery, four weeks of intrusion and another four weeks of retention was executed on the right incisors while left incisors served as the control. Through the histologic analysis, following results were obtained. 1. The periodontal lesion which was produced by elastics and artificial bony defect was characterized by three walled infrabony pocket. 2. In the histologic section of control side, the base of the pocket was located below the level of the cemento-enamel junction. Connective tissue attachment was formed apically from the base of the pocket. 3. On the experimental side, the base of the pocket was localized close to the cemento-enamel junction. Connective tissue attachment was formed near to pocket base and extended apically. 4. New cementum was formed from the notch coronally toward the epithelial junction along the root surface in the both intruded incisors and control. 5. In the fluorescence microscopic observation, bone regeneration was began at the base of defect and the remodelling pattern characterized by a combination of coronal bone generation and resorption of the marginal crest could be detected. Although the remodelling pattern was the same in the both side, the bone remodelling in intruded incisors was continued during tooth movement. The results of the present study suggest that an orthodontic intrusion of extruded incisors with vertical bony defect can be carried out with a desirable periodontal response, provided that both the oral hygiene and the biomechanical force system are kept under control.

백서 두개관세포에서 Ipriflavone이 골조직 개조에 미치는 영향

이용승,김영준,이기헌,황현식 대한치과교정학회 2005 대한치과교정학회지 Vol.35 No.4

본 연구는 ipriflavone (isopropoxyisoflavone)의 투여가 백서 두개관세포의 증식과 골조직 개조에 미치는 영향을 알아보고자 시도되었다. 태령 20-21일째의 백서 두개관세포를 분리 배양한 후, 10^(-9) M부터 10^(-5) M까지 농도의 ipriflavone을 투여하고 1일째와 3일째에 MTT 분석을 시행하여 흡광도를 평가한 결과, 모든 농도에서 백서 두개관세포의 증식을 보이지 않았다. 한편 골조직 개조에 미치는 영향을 알아보기 위하여 14일째에 alizarin red염색을 시행하여, 형성된 석회화 결절 면적을 측정하였을 때, 10^(-8) M, 10^(-7) M, 10^(-6) M 농도를 투여한 경우 석회화 결절 형성이 유의하게 증가하였다. 골아세포의 분화에 미치는 영향을 알아보기 위하여 ipriflavone을 투여하고 7일째와 14일째에 추출한 RNA를 역전사 중합효소 연쇄반응(RT-PCR)을 시켜 bone sialoprotein (BSP), type 1 collagen (COL I), osteocalcin (OCN) 유전자 발현을 관찰한 결과 BSP와 COL I 유전자는 배양 7일째 높은 발현을 보였고, OCN 유전자는 배양 14일째 높은 발현을 보였다. 이상의 연구결과 ipriflavone이 백서 두개관세포에서 석회화를 촉진시키고 골아세포의 분화에 관여하는 BSP, COL I 및 OCN 유전자 발현을 증가시켜 골조직의 개조를 빠르게 할 수 있음을 시사하였다. lpriflavone (isoprofoxyisoflavone), a synthetic derivative from soy isoflavone diazein, has been shown to inhibit bone resorption and perhaps stimulate bone formation. This study was performed to examine the effects of ipriflavone on the proliferation and bone remodeling in rat calvarial cells in vitro. The rat calvarial cells were isolated from fetus aged 20 to 21 days and cultured in BGJb media. The graded concentration of ipriflavone (10^(-9)-10^(-5) M) was administered into cultured cells. When the cell proliferation was estimated through the measurement of MTT assay, there was no increase in cellular proliferation of the rat calvarial cell at any ipriflavone concentration. The cellular activity was evaluated through the formation of mineralized nodules stained by alizarin red. The formation of mineralized nodules significantly increased at concentrations of 10^(-8) M, 10^(-7) M and 10^(-6) M ipriflavone. Reverse transcription-polymerase chain reaction analyses (RT-PCR) were done at 7 and 14 days after culture to detect the expression of Bone Sialoprotein (BSP), Type I collagen (COL I) and Osteocalcin (OCN). As a result, the expressions of BSP and COL I increased of the 7th day of culture and the expression of OCN increased on the 14th day of culture. These results indicate that ipriflavone facilitates the bone remodeling process by promoting rat calvarial cell differentiation and stimulating mineralization through increased expression of extracellular matrix genes, such as BSP, COL I and OCN.

Piezoelectrically modulated touch pressure sensor using a graphene barristor

Hwang, Hyeon Jun,Kim, So-Young,Kang, Soo Cheol,Allouche, Billal,Yang, Jin Ho,Lee, Byoung Hun Institute of Pure and Applied Physics 2019 Japanese Journal of Applied Physics Vol.58 No.2

Identification of novel serum biomarkers for anti-asthmatic effects of fermented Asparagus cochinchinensis in an ovalbumin-induced asthma mouse model

Hyeon-Jun Choi,Jun-Young Choi,So-Yeon Kim,Ji-Eun Kim,Jin-Ju Park,Mi-Rim Lee,Bo-Ram Song,Ji-Won Park,Mi-Ju Kang,Su-Ji Bae,Young-Suk Jung,Dae-Youn Hwang,Jun Go,Yu-sang Choi,Young-Ju Lee 한국실험동물학회 2019 한국실험동물학회 학술발표대회 논문집 Vol.2019 No.1

세척이 가능한 원통 코일형 열교환기의 파울링 특성에 관한 연구

황준현(Jun Hyeon Hwang),나병철(Byung Chul Na),오세기(Sai Kee Oh),구경민(Kyoung Min Koo),이재근(Jae Keun Lee),안영철(Young Chull Ahn) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.2

In this work, we studied the shell and helically coiled tube heat exchangers. Shell and coil heat exchangers with different rate of water flow and plate heat exchanger with same capacity were tested for condensing conditions. We proposed design guide using modified Wilson plot method. We compared fouling characteristics between shell and coil heat exchanger and plate heat exchanger, when they were washed and were not washed. The shell and coil heat exchanger showed 120% of higher saturated fouling resistance value and 4% of better heat transfer ratio than the plate heat exchanger.

비대칭 난류 채널 유동에서 벽 부착 구조

황준혁(Jun Hyuk Hwang),황현규(Hyeon Gyu Hwang),이재화(Jae Hwa Lee),황진율(Jinyul Hwang) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.6

비대칭 난류 채널 유동의 직접 수치 모사를 통해 벽 부착 구조의 특성을 조사하였다. 벽면 속도가 증가하면서 최대 평균 속도의 위치가 정지한 벽면으로 이동한 비대칭 층(layer)을 형성하였다. 양 벽면의 레이놀즈 수는 증가하지만, 정지한 벽면에서 평균속도의 대수 영역 (log region)은 짧아지고 움직이는 벽면에서는 확대되었다. 난류 강도는 정지한 벽면에서 감소하고 움직이는 벽면에서 증가하는 것을 보여주었다. 또한, 스펙트럼 분석은 kz-1 영역이 정지한 벽면에서 짧아지고, 움직이는 벽면에서 확장되는 것을 보여준다. 이는 큰 구조 (large-scale motion)의 변화가 벽 부착 구조의 차이를 초래하여 비대칭 채널의 난류 특성에 큰 영향을 주는 것을 알 수 있다. The DNSs of turbulent asymmetric channel flows are performed to examine the characteristics of wall-attached structures. As the moving wall velocity increases, the position of the maximum mean velocity are shifted to the stationary wall, creating asymmetric layer. Although the Reynolds numbers on both walls increase, the logarithmic layer is shortened on the stationary wall, and extended on the moving wall. The turbulent intensities shows that the turbulent activity decreases on the stationary wall and increases on the moving wall. The spectral analysis also shows the shortened/extended kz-1 region clearly, reminiscent the suppression/growth of wall attached structures. The variation of large-scale motions between the stationary and moving walls influence on the difference of wall attached structure and contribute to the turbulent characteristics of an asymmetric wall-bounded flows.