허혈성 심질환에 있어서 아데노신 급속 정맥투여후 관동맥압의 변화에 관한 연구

봉종대,오종용,배성한,신원용,김철현,이광희,최태명,현민수,김성구,권영주 순천향의학연구소 1998 Journal of Soonchunhyang Medical Science Vol.4 No.2

Background: Adenosine interacts with A1 receptors present on the extracellular surface of cardiac cells, activating K+channels in a fashion. It produces coronary vasodilatation and AV nodal block. The half-time is one to six second and has ultra-short action. In ischemic heart disease, fractional flow reserve(FFR) can be achieved safely with intravenous adenosine infusions at a rate of 150㎍/kg/min which cause maximal coronary hyperemia. Purpose: We investigated the patients who have had ischemic heart disease(n=8). After adenosine intravenous administration(150㎍/kg/min), the effect cause maximal hyperemia of coronary artery. During peak maximal hyperemia, we reported clinical findings, coronary hemodynamics and electrocardiogram findings. Methods: After diagnostic coronary angiography and left ventriculography, catheter was advanced into the ostium of coronary artery. We investigated coronary hemodynamics such as systolic coronary artery pressure, diastolic coronary artery pressure, mean coronary artery pressure and heart rate. To assess the use of adenosine for determination of fractional flow reserve, hemodynamics and electrocardiogram were measured at basal state and during peak maximal hyperemia. Results: Symptoms developed 1.5-2 minute after adenosine intravenous administration and each symptom disappeared 2-2.5 minute after adenosine administration. Two patients represented asymptomatic appearance and six patients complained of flushing, chest pain, palpitation and headache. In eight patients with ischemic heart disease, 1.5 minute after venous administration of 150㎍/kg/min of adenosine, coronary artery pressure decreased and heart rate increased significantly. Conduction abnormalities after administration of 150㎍/kg/min of adenosine were transient 2nd degree AV block 2 cases(25%). Conclusions: Adenosine is a potent ultra short-acting vasodilator. Although coronary artery pressure decreased and heart rate increased and mild cardiovascular symptoms occurred after continuous infusion of 150㎍/kg/min of adenosine, it is useful as an agent for determination of fractional flow reserve.

전치부 개교합을 가진 골격성 제 Ⅲ급 부정교합 환자에 있어서 하악지 시상분할 골절단술후 술후 안정성에 관한 평가

임재석,권종진,장현석,손형민,남영원,최철민 대한악안면성형재건외과학회 2000 Maxillofacial Plastic Reconstructive Surgery Vol.22 No.6

The purpose of this study is to assess the postoperative stability and the tendency of relapse after both sagittal split ramus osteotomy in skeletal class III with anterior open bite. This retrospective study was based on the examination of 15 patients, 6 males and 9 females, with a mean age 23.1 years. The patients were divided into two groups based on the amount of preoperative overbite(group I:<1mm, group II:≥1mm). Serial lateral cephalometric radiographs were taken within 2 weeks preoperatively, within 1 week postoperatively and at a follow up period that ranged from 7 to 24 months postoperatively. All cephalometric radiographs were traced and digitized using the Quick ceph image Pro for analysis. And then, horizontal and vertical changes of reference points(B point, Pogonion, L1) were assessed by the linear measurements in millimeters on both axes. The results were as follows : 1 Mean horizontal relapses were 0.67±0.93mm (11%) at B point (P<.05) and 0.81±1.01mm (13.2 %) at Pogonion (P<.01). 2, Mean vertical relapses were 0.63±1.62mm (33.3%) at B point and 0.53±1.95mm (31.4%) at Pogonion (P>.05) 3. The mean angular change of occlusal plane to SN was 0.24±1.19 (P>.05) and that of mandibular plane to SN was 1.03±1.85 (P<.05). 4. There was correlation between the extent of preoperative overbite and the postsurgical relapse at B point and Pogonion. 5. There was no correlation between the amount of surgically produced horizontal movement and the postoperative horizontal relapse at B point.

흉통의 양상에 따라 분류한 불안정형 협심증 환자의 임상적 소견의 비교

김명수,김성구,정호석,온영근,신원용,김철현,최태명,현민수,권영주 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.1

Background and aims : The clinical syndrome unstable angina pectoris that encompasses a variety of symptoms and clincal presentations of transient episode of myocardial ischemia, was devided to several subgroups. Also, it has variable pathophysiologic factors to cause myocardial ischemia. According to clincal presentation, coronary angiographic finding and prognostic factor, the result of unstable angina pectoris is variable. In fact, there were a few data reported on the prognosis of wide spectrum of patients with unstable angina. However, the precise risk of subgroups according to classitication has not been established because it was difficult to compare between studies. We classified unstable angina pectoris by clinical nature of chest pain, and performed to establish and compare the clinical presentations, coronary angiographic findings, treatement and prognosis of patients with unstable angina within subgroups of classification. Methods : Retrospenctive data for 164 unstable angina pectoris patients admitted to the Internal Cardiology Division of Soon Chun Hyang University Hospital from May 1996 to July 1999 was analyzed. The patients were classified into one of the following categories: Class I, new onset of severe angina; Class II, acceleration of previous chronic stable angina; Class III, angina at rest. Clinical presentations, echocardiographic findings, coronary angiographic findings, treatment and prognosis were compared. Results : From the total 164 patients, the subjects of classes were as follows : Class I, 46 cases (28.1%); Class II, 74 cases (45.1%); Class III, 44 cases (26.8%). In view of age distribution, the 7th decade had the highest incidence, and then, 6th, 8th decades were followed. There was no baseline differences among the 3 classes with respect to gender, number of risk factors. Significantly, class II showed more severe findings in abnormal Q wave 15 cases (20.8%), total occclusive lesion 10 cases (20.8%) and three vessel coronary disease 11 cases (22.9%) than other classes. The change of ST segment was significantly apparent (p<0.02) among class I 28 cases (60.8%), class III 26 cases (59.0%), comparing with class II 30 cases (40.5%). Class III had the higher incidence of one vessel coronary artery disease than class I and III. The heparin treatment was performed in 99 cases (60.1%). The incidence of nonfatal myocardial infarction was much more in class I and III, each 4 cases (8.7%, 9.8%) than in class II 1 cases (1.4%). In-Hospital death was occurred in class I and II, each 1 case. Conclusion : The patients with the acclerated angina from chronic stable angina had more severe coronary artery disease than other classes, but they had better in-hospital prognosis.

관상동맥질환 환자에서 스텐트 시술 후 재협착에 관한 연구

강진환,권영주,박상호,한대희,이상철,김명구,변정득,최병조,심규혁,온영근,현민수,김성구 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background and aims : In the coronary artery disease, a rate of restenosis was much decreased by placement of coronary stent than when percutaneous transluminal coronary angioplasty has been applied, but there are still important clinical problems of restenosis. There has been many progressive studies about various factors contributed to this restenosis. So, we studied a relation between restenosis after placement of coronary stent in the coronary artery disease and many clinical factors, characteristics of stenotic lesion and procedural factors, and also assessed the restenosis rate of various coronary stents. Methods : Total 58 lesions(46 cases of patients ; man 30, woman 16) were evaluated, which has been performed a follow-up coronary angiography after 6 months (mean 188 days) since coronary stent had been placed. Various stents were implanted and assessed a relation between restenosis and many factors. Results : Of 58 lesions were target stenotic studies, there were 22 of restenotic lesions(37.9%), and the restenosis rate wes statistically significant difference in the relation with diabetes mellitus(p<0.05), group of acute myocardial infarction(p<0.05) among clinical diagnosis of ischemic heart disease(stable angina, unstable angina and acute myocardial infarction) in clinical factors and with high dilation pressure of stent(p<0.05) in procedural factors. When the rate of restenosis was evaluated among implanted stents, it was lowest in the Multilink^(®) stent and highest in the Nir Royal^(®) stent(60%). Conclusion : In this study of restenosis and various factors after placement of stents in the coronary artety disease, factors such as diabetes mellitus, group of acute myocardial infarction and a dilation pressure of stent were significant related with restenosis and the restenosis rate of Multilink^(®) stent was lowest and the highest restenosis rate was of Nir Royal^(®) stent.

만성 심부전환자의 혈액에서 측정한 Tumor necrosis factor-α 및 Interleukin-6의 임상적 의의

김명구,김성구,박상호,한대희,강진환,변정득,심규혁,최병조,방덕원,온영근,현민수,권영주 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background and objectives: Many conditions are responsible for the pathophysiology and progressive mechanisms of congestive heart failure. More recently, it has also become evidence that another class of biologycally activated molecules generically reffered to as cytokine these are also over expressed in congestive heart failure. Therefore, the purpose of this study was to measure concentrations of tumor necrosis factor-α(TNF-α), interleukin-6(IL-6) in mild to severe symptoms of heart failure and compare their values with those found in normal control and analysed correlation relationship between cytokine level, clinical findings and hemodynamic indicies. Subjects and Methodology: Levels of TNF-α and IL-6 were measured on pulmonary artery during cardiac catheterization in heart failure patients(n=32) and normal subjects(n=8) as well as physical examination and echocardiogram. Cytokines assay were performed on plasma using commercially available ELISA(Enazyme-Linked Immunosorbent Assay) kits. Results: Although the levels of TNF-α and IL-6 tend to increase in congestive heart failure group, the cytokines level was not made significantly statistical difference between congestive heart failure group and controls. When analyzing the correlation between the levels of PCWP(pulmonary capillary wedge pressure) and cytokines(TNF-α, IL-6), respectively, there were statistically significant correlation coefficient 0.32,(p<0.05), 0.39(p<0.01). The cytokine IL-6 and pressure of pulmonary artery were significant correlation.(correlation coefficient 0.36, p<0.02) More significantly, there was correlated with TNF-α and IL-6.(correlation coefficient 0.57, p<0.001) Conclusions: There was tended toward high concentration of TNF-α & IL-6 in congestive heart failure and significant difference for PCWP between TNF-α & IL-6, thus may be correlated with development and progression in congestive heart failure.

허혈성 심질환에서 염증지표에 관한 연구

번정득,권영주,박상호,한대희,이상철,강진환,김명구,심규혁,최병조,온영근,현민수,김성구 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background : Atherosclerosis is the chief underlying cause of ischemic heart disease and there is increasing evidence that inflammation is an important determinant of the development of atherosclerosis. We assessed the levels of inflammatory markers in patients with ischemic heart disease and normal group who has normal coronary angiograms. Materials and Methods : Coronary angiography was performed in 142 patients. 107 patients of ischemic heart disease(stable angina pectoris 58, unstable angina pectoris 30, Acute myocardial infarction 19) and 38 normal control subjects. We assessed the level of inflammatory markers, such as CRP, ESR, fibrinogen and leukocyte. Results : CRP, ESR and fibrinogen values of the patients with stable angina pectoris and unstable angina pectoris were higher than that of normal control group, but there were no statistical significance. Leukocyte value of the patients with unstable angina pectoris(9003.3±701.5/mm^(3)) was significantly higher than that of the patients with stable angina pectoris(6685.5±245.8/mm^(3)) and normal control subjects(6394.3±235.1/mm^(3)). CRP, ESR and fibrinogen values of the patients with acute myocardial infarction were also higher than that of normal control subjects. CRP was 3.88±2.05 mg/dL in acute mocardial infarction group, and 0.29±0.15 mg/dL in normal control subject group(p<0.05). Fibrinogen was 541.6±45.1 mg/dL in acute myocardial infarction group, 321.4±25.6 mg/dL in normal control subject group(p<0.05). Leukocyte was 10942.1±737.6/mm^(3) in acute myocardial infarction group, 6394.3±235.1/mm^(3) in normal control subject group(p<0.05). Conclusions : This study demonstrate that CRP, fibrinogen and leukocyte values of acute myocardial infarction group were significantly higher than that of control group and stable, unstable argina pectoris group. Leucokyte values were significantly elevated in unstable angina group, but CRP values were not in unstable angina group.

The Structural-Dependent Characteristics of Rashba Spin Transports in In_0.5Ga_0.5As/In_0.5Al_0.5As Heterojunctions

Choi, Hyon-Kwang,Hwang, Sook-Hyun,Jeon, Min-Hyon,Yamda, Syoji The Korean Institute of Electrical and Electronic 2011 Transactions on Electrical and Electronic Material Vol.12 No.4

The growth and characterization of $In_{0.5}Ga_{0.5}As/In_{0.5}Al_{0.5}As$ narrow-gap inverted high electron mobility transistor structures, developed as a candidate material for spin-injection devices, are presented in this study. We have grown samples possessing surface $In_{0.5}Ga_{0.5}As$ channels of different thicknesses (30 nm and 60 nm) both with and without a thin 3 nm $In_{0.5}Ga_{0.5}As$ cap layer by using molecular beam epitaxy. We then investigated the in-plane transport properties as well as the Rashba spin-orbit coupling constant of the two-dimensional electron gas confined at the heterojunction interface.

반송자 적분 알고리즘을 이용한 협폭 효과의 모의실험

최창현(Chang-Hyon Choi),윤현민(Hyon-Min Yun),김철성(Chul-Sung Kim) 대한전자공학회 1995 대한전자공학회 학술대회 Vol.1995 No.12

Smart Buffering for seamless handover in Proxy Mobile IPv6

Choi, Hyon‐,Young,Kim, Kwang‐,Ryoul,Lee, Hyo‐,Beom,Min, Sung‐,Gi,Han, Youn‐,Hee John Wiley Sons, Ltd. 2011 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.11 No.4

<P><B>Abstract</B></P><P>Proxy Mobile IPv6 (PMIPv6) is proposed as a new network‐based mobility protocol and it does not require MN's involving in mobility management. MN can handover relatively faster in PMIPv6 than in Mobile IPv6 (MIPv6) because it actively uses link‐layer attachment information and reduces the movement detection time, and eliminates duplicate address detection procedure. However, the current PMIPv6 cannot prevent packet loss during the handover period. We propose the Smart Buffering scheme for seamlessness in PMIPv6. The Smart Buffering scheme prevents packet loss by proactively buffering packets that will be lost in a current serving mobile access gateway (MAG) by harnessing network‐side information only. It also performs redundant packet elimination and packet reordering to minimize duplicate packet delivery and disruption of connection‐oriented flows. To fetch buffered packets from a previous MAG, a new MAG discovers the previous MAG by using a discovery mechanism without any involvement of an MN. We verified the effectiveness of Smart Buffering <I>via</I> simulation with various parameters. Copyright © 2009 John Wiley & Sons, Ltd.</P>

Annealing Effects of ZnO Seed Layers on Structural and Optical Properties of ZnO Nanorods Grown on R-plane Sapphire Substrates by Hydrothermal Method

( Min Su Kim ),( Gi Woong Nam ),( Dong Wan Kim ),( Ha Eun Kim ),( Haeri Kang ),( Wook Bin Lee ),( Hyon Kwang Choi ),( Yang Soo Kim ),( Jae Young Leem ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.2

ZnO nanorods were hydrothermally grown on R-plane sapphire substrates coated with an as-grown ZnO seed layer and with ZnO seed layers annealed at different temperatures. The effects of the seed-layer annealing temperature on the structural and optical properties of the ZnO nanorods were investigated using scanning electron microscopy, X-ray diffraction, and photoluminescence. ZnO nanorods and nanosheets grew on the as-prepared seed layer. Only ZnO nanorods grew on the ZnO seed layer annealed above 700 ℃. The structural and optical properties of the ZnO nanorods were significantly enhanced when the seed layers were annealed at 700 ℃. A cubic equation was used to establish the non-linear exciton radiative lifetime of the free exciton emission peak. Varshni’s empirical equation fitting parameters were α = 4 × 10.3 eV/K, β = 1 × 104 K, and Eg(0) = 3.335 eV; the activation energy was ~94.6 meV.