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Inhibition of Various K+ Current by Ofloxacin in Neonatal rat Ventricular Myocytes
박상웅,오승범,구재웅,성동준 한국웰니스학회 2018 한국웰니스학회지 Vol.13 No.3
Fluoroquinolones are among the most widely used broad-spectrum antibiotics. Although ofloxacin is deemed to be relatively safe, whether side effects occur in the heart is unclear. This pilot study investigated the effect of ofloxacin on various K+ channel currents as well as L-type Ca2+ channel currents. The various K+currents were examined with a voltage pulse protocol using multi-step pulses, with a step to-120mV followed by a depolarizing step to +50mV and then to –40mV from holding potential of –80mV. L-type Ca2+ currents were measured at 0mV after prepulse to –40mV. Ofloxacin inhibited the various K+ currents, with IC50 values of 850μM for IKir, 6.8μM for IKs, and 0.4μM for IKr. Ofloxacin did not affect the L-type Ca2+ currents. We suggest that potential cardiac side effects, such as action potential prolongation and arrhythmia, maybe induced by ofloxacin.
무선 통신 가능 범위와 V2X 차량 비율에 관한 경험적 분석
박상웅,김주영,나성용,이승재 한국ITS학회 2016 한국ITS학회논문지 Vol.15 No.5
V2X 환경은 C-ITS 분야에서도 최신 기술을 토대로 활발한 연구가 진행되고 있는 분야이다. 이런 최신 기술을 평가하기 위해 통신가능범위와 V2X 차량의 시장 점유율이 사용되고 있다. 본 연구는 적절한 파라미터와 V2X 차량 속도 전달 알고리즘을 적용한 미시적 교통시뮬레이션 VISSIM을 사용해 V2X 환경에서의 통신가능 범위와 V2X 차량의 시장점유율이 교통류의 흐름에 어떤 영향을 끼치는지 분석하였다. 연구 결과, V2X 환경은 차량의 교통량에 의한 혼잡을 줄여주는데 효과적인 것으로 나타났다. 하지만, 도로 용량에 근접한 혼잡상황일 시에는 V2X 환경 역시 도로 상태를 개선할 수 없었다. 또한 통신가능 범위가 길수록 효율적인 것은 아니라는 것과 낮은 시장점유율을 가지고도 V2X환경의 효과를 볼 수 있음이 밝혀졌다. 본 논문은 V2X 환경을 더 효율적으로 평가할 수 있게 만드는 하나의 기반이 될 것이다. V2X environment is the most popular part of the C-ITS based on the high technologies. To evaluate V2X environment technologies, radio communication range and market penetration rate of V2X vehicle are used. This paper studies the V2X environment considering various traffic congestion level, radio communication range and market penetration rate of V2X vehicle using the microscopic simulation (VISSIM) based on proper parameters and algorithm. In conclusion, V2X environment can reduce the congestion in proper traffic volume. However, if traffic volume is almost near the capacity, even V2X environment can’t relieve the road condition. Furthermore, increase of the radio communication range does not always mean the decrease of the congestion and even with the small market penetration rate, it can also have an impact on the V2X environment. This result will be the foundation for the V2X environment much better.
Facilitation of serotonin-induced contraction of rat mesenteric artery by ketamine
박상웅,노현주,김정민,김보경,조성일,김윤수,우남식,김성훈,배영민 대한약리학회 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.6
Ketamine is an anesthetic with hypertensive effects, which make it useful for patients at risk of shock. However, previous ex vivo studies reported vasodilatory actions of ketamine in isolated arteries. In this study, we reexamined the effects of ketamine on arterial tones in the presence and absence of physiological concentrations of 5-hydroxytryptamine (5-HT) and norepinephrine (NE) by measuring the isometric tension of endothelium-denuded rat mesenteric arterial rings. Ketamine little affected the resting tone of control mesenteric arterial rings, but, in the presence of 5-HT (100~200 nM), ketamine (10~100 μM) markedly contracted the arterial rings. Ketamine did not contract arterial rings in the presence of NE (10 nM), indicating that the vasoconstrictive action of ketamine is 5-HT-dependent. The concentration-response curves (CRCs) of 5-HT were clearly shifted to the left in the presence of ketamine (30 μM), whereas the CRCs of NE were little affected by ketamine. The left shift of the 5-HT CRCs caused by ketamine was reversed with ketanserin, a competitive 5-HT2A receptor inhibitor, indicating that ketamine facilitated the activation of 5-HT2A receptors. Anpirtoline and BW723C86, selective agonists of 5-HT1B and 5-HT2B receptors, respectively, did not contract arterial rings in the absence or presence of ketamine. These results indicate that ketamine specifically enhances 5-HT2A receptor-mediated vasoconstriction and that it is vasoconstrictive in a clinical setting. The facilitative action of ketamine on 5-HT2A receptors should be considered in ketamine-induced hypertension as well as in the pathogenesis of diseases such as schizophrenia, wherein experimental animal models are frequently generated using ketamine.
미시적 교통 시뮬레이션을 활용한 실시간 수요대응형 자율주행 버스 영향 평가
박상웅,김주영 한국ITS학회 2022 한국ITS학회논문지 Vol.21 No.6
실시간 수요대응형 자율주행 버스는 자율주행 버스와 실시간 수요대응형 버스의 단점을 상 쇄시킨 미래교통수단이다. 하지만 버스 기능의 고도화로 실시간 수요대응형 자율주행 버스 도 입 시 영향에 관한 정량화된 연구는 활발하지 않은 실정이다. 본 연구에서는 강화학습 기반 실시간 수요대응형 자율주행 버스를 미시적 교통 시뮬레이션에 적용하여 실시간 수요대응형 자율주행 버스의 정량화된 효과평가를 실시하였다. 구체적으로 수요 변화에 따라 실시간 수 요대응형 자율주행 버스가 도로 네트워크에 끼치는 영향과 이용자 대기시간을 미시적 시뮬레 이션 안에서 구현하였다. 시뮬레이션 대상지로는 한국교통대학교 인근을 선정하였다. 시뮬레 이션 결과, 실시간 수요대응형 자율주행 버스는 기존 노선 고정형 버스 대비 이용자 대기시간 과 평균제어지체는 감소하였고, 평균통행속도는 증가하였다. 본 연구를 통해 실시간 수요대응 형 버스의 도입을 정량적으로 평가하는 것이 기대된다. An autonomous demand-responsive bus with mobility-on-demand service is an innovative transport compensating for the disadvantages of an autonomous bus and a demand-responsive bus with mobility-on-demand service. However, less attention has been paid to the quantitative impact assessment of the autonomous demand-responsive bus due to the technological complexity of the autonomous demand-responsive bus. This study simulates autonomous demand-responsive bus trips by reinforcement learning on a microscopic traffic simulation to quantify the impact of the autonomous demand-responsive bus. The Chungju campus of the Korea National University of Transportation is selected as a testbed. Simulation results show that the introduction of the autonomous demand-responsive bus can reduce the wait time of passengers, average control delay, and increase the traffic speed compared to the results with fixed route bus service. This study contributes to the quantitative evaluation of the autonomous demand-responsive bus.