• Korean Journal of Veterinary Service
• /
• v.19 no.2
• /
• pp.154-162
• /
• 1996

The effcets of adenosine 5'-triphosphate(ATP) were investigated on the uterine smooth muscle motility in the pig. The results were summarized as follows: 1. The effects of the porcine uterine smooth muscle and the contractile responses increased between the concentration of ATP $10^{-5}$ and $10^{-3}$ M with a dose-dependent manner. 2. The contractile response induced by ATP($10^{-4}$ M) was not blocked by pretreatment with cholinergic receptor blocker, atropine ($10^{-6}$ M) 3. The contractile response induced by ATP ($10^{-4}$ M) was not blocked by pretreatment with $\alpha$ -adrenergic receptor blocker, phentolamine(10$^{-6}$ M) and ${\beta}$-adrenergic blocker, propranolol ($10^{-6}$ M). 4. The contractile response induced by ATP($10^{-4}$ M) was not appeared in 4Ca^{++}$ -free medium. As the concentration of $Ca^{++}$ in $Ca^{++}$ -free medium was increased, the contractile response induced by ATP ($10^{-4}$ M) was enhenced but was completely inhibited by pretreatment with $Ca^{++}$ -channel blocker, papaverine($10^{-6}$ M) or verapamil($10^{-6}$ M). From these results, it was conclued that the effects of ATP were the contraction mediated by purinergic receptor in uterine smooth muscle of pig.

• Clinical and Experimental Pediatrics
• /
• v.46 no.2
• /
• pp.167-172
• /
• 2003

Purpose : Pulmonary vascular hypertension is a common problem in congenital heart disease, the most common cardiac condition in childhood. However, the mechanisms responsible for this pathologic change, treatment, and prevention are poorly understood. Therefore, we studied the gene expression of vascular endothelial growth factor(VEGF) by using a hypoxic model of the pulmonary artery smooth muscle cells. Methods : The main pulmonary artery and its proximal branches of a 6 wk old Fischer rat were excised. They were cut into multiple small pieces and suspended in DMEM medium supplemented with 20% fetal bovine serum and incubated in 5% $CO_2$-95% air atmosphere. The smooth muscle cells were confirmed by immunostaining with smooth muscle myosin and ${\alpha}$-smooth muscle actin antibodies. The VEGF gene expression in the hypoxic group was compared with the one in control the group as well as the one in the starved group by RT-PCR and Northern blot hybridization. Results : There was no statistically significant difference among the control, hypoxic and starved groups. Conclusion : There are few studies of pulmonary vascular hypertension at the molecular level in Korea. Therefore, we studied the expression of VEGF gene in hypoxic pulmonary vascular smooth muscle cells. Further studies will be needed to find the difference between newly born and adult rats, or human and rat pulmonary vascular smooth muscle cells in gene expression. We hope that the study will lead to a better understanding of pulmonary vascular hypertension.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.25 no.4
• /
• pp.281-294
• /
• 1999

Vasospasm causes microvascular surgery to fail as a main factor in the loss of transferred flap dye to the diminution of blood flow in reconstruction surgery. Although there has been extensive research to resolve the vasospasm problem, no one has reached an ideal solution to date. However, cryotherapy, which is often used for destruction of tumor lesions, is being presented as a new way of releasing vasospasm. After making a histomorphometric measurement on vasodialation during the course of 1, 3 and 7 days, 2 and 4 weeks, and 5 months periods and observing the change of blood vessel in a histologic, immunohistochemical, and scanning electronic microscopic approach, the results were as follows : 1. Vascular inner diameters of the experimental 1 and 3 days groups were measured $476.3{\pm}28.20{\mu}m$, $497.15{\pm}48.79{\mu}m$ respectively showing statistically meaningful vasodilation(P<0.05), which continued by the experiment 4 weeks group. However, in the experimental 5 months group, the vascular inner diameter appeared similar to the control groups. Even though the thickness of smooth muscular layers come out to be thinner in all the experimental groups compared to the control group, it was difficult to find any statistical meaningfulness. In addition, the vascular external diameters of every experimental groups were shown to be longer than the control group. 2. In light microscopic view, severe injury was evident on the smooth muscular layer cell from the experimental 1 day group, started recovering partially from the experimental 7 days group, and was mostly restored in the experimental 4 weeks group and layer of adventitial stripping were nearly recoverd 2 weeks group. 3. The PCNA positive cells of smooth muscular layer were observed from the experimental 7 days group and had a tendency to increase by the experimental 2 weeks group. In the experimental 4 weeks and 5 months group, the number of PCNA possitive cells observed was comparable to the control group. 4. ${\alpha}$-SMA level of smooth muscular layer cells, having been significantly lower than the control group in the severly damaged experimental 1 day group. It was seen to be increased in the experimental 7 days group and turned out to show similar ${\alpha}$-SMA level in 4 weeks to the control group. 5. In the view of SEM, the endothelial cells were destructed and falling off, and also present the appearance of flattening in the experiment 1 day group. The endothelial layer cells started partially recovering from the 7 days group after the freezing injury. On 4 weeks and 5 months, the endothelial cells were fully coverd the damaged area, also it's appearance is similar to control group. In conclusion, the vascular freezing after the removal of adventitia caused damages to smooth muscular layer cells, and brought about vasodilation, which continued by the 4th week. The smooth muscular layer cells started partially reviving from the 7rd day after the damage by vascular freezing, and recovered their similar figure to the control group's 4 weeks later. This was considered the result of cells which surround the damaged blood vessel being influxed into the smooth muscular layers. Therefore, this local freezing injury on the blood vessel was thought to be applied clinically to relieve severe vasospasm which cannot be treated by vasodilation drug, a microvascular surgery.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.6 no.2
• /
• pp.127-137
• /
• 2006

This paper presents an $H_{\infty}$ controller synthesis method for discrete time fuzzy dynamic systems based on a piecewise smooth Lyapunov function. The basic idea of the proposed approach is to construct controllers for the fuzzy dynamic systems in such a way that a Piecewise smooth Lyapunov function can be used to establish the global stability with $H_{\infty}$ performance of the resulting closed loop fuzzy control systems. It is shown that the control laws can be obtained by solving a set of Bilinear Matrix Inequalities (BMIs). An example is given to illustrate the application of the proposed method.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2534-2536
• /
• 2003

Color는 다른 물체로부터 하나의 물체를 특정짓기 위한 효과적이고 강인한 실마리이므로 color clustering이 많은 주목을 받고 있다. 그러나 불규칙한 조명변화에 의한 color 변이 때문에 color segmentation은 매우 어렵다. 이 논문은 B-spline 곡선을 이용한, HSI color space에서의 intensity 정보를 포함한 신뢰할 수 있는 color modeling 방법을 제안한다. 이것은 비록 HS 평균임에도 불구하고 단색 물체의 color 분포가 조명이 변함에따라 변한다는 사실에 기반한다. 이 접근법을 사용하면 피부색을 가진 영역의 color clustering이 불규칙한 조명변화에 적응될 수 있다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.12
• /
• pp.1709-1717
• /
• 2015

In remote islands PV (Photo Voltaic) panel with BESS (Battery Energy Storage System) supplies electric power to the customers in parallel operation with EG (Engine Generator) to save fuel consumption and to mitigate environmental load. BESS operates in voltage control mode when it supplies power to the load alone, while it operates in current control mode when it supplies power to the load in parallel with EG. This paper proposes a smooth mode change scheme from current control to voltage control of BESS by adding proper initial value to the integral part of voltage control, and a smooth mode change scheme from voltage control to current control by tracking the EG output voltage to the BESS output voltage using PLL (Phase-Locked Loop). The feasibility of proposed schemes was verified through computer simulations with PSCAD/EMTDC, and the feasibility of actual hardware system was verified by experiments with scaled prototype. It was confirmed that the proposed schemes offer a seamless operation in the stand-alone power system in remote islands.

• 전기의세계
• /
• v.29 no.8
• /
• pp.491-494
• /
• 1980

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.90.4-90
• /
• 2002

• 대한약리학회:학술대회논문집
• /
• 2006.10a
• /
• pp.84.2-84.2
• /
• 2006

• The Korean Journal of Physiology
• /
• v.24 no.1
• /
• pp.77-90
• /
• 1990

There have been conflicting reports concerning the effect of Panax ginseng on the contractility of vascular smooth muscle, i.e., Panax ginseng extract has been reported to cause relaxation, contraction or to have no effect on the tension of vascular smooth muscle. A further investigation of $Ca^{++}$ stores which supply $Ca^{++}$ for contraction of vascular smooth muscle is needed to understand the underlying mechanisms of this conflicting effect of ginseng alcohol extract (GAE). The present study was intended to examine the sources of calcium mobilized for contraction of vascular smooth muscle by GAE. Aortic ring preparations were made from the rabbit thoracic aorta and endothelial cells were removed from the ring. The contractility of the aortic ring was measured under various experimental conditions and $Ca^{++}$ flux across the membrane of aortic ring and the sarcoplasmic reticulum and mitochondria were measured with a calcium selective electrode. The result were summarized as follows; 1) At low concentration of extracellular $Ca^{++}$, GAE increased the contractility of vascular smooth muscle in dose-dependent fashion except high concentration $Ca^{++}$ (1 mM). 2) In the presence of ryanodine, GAE still increased contractility of vascular smooth muscle as much as control group, but in the presence of caffeine, GAE increased it significantly. i.e. Their effects seemed to be additive. 3) In the presence of verapamil+lanthanum, and verapamil+lanthanum+ryanodine, the contractility of the vascular smooth muscle was decreased, but a dose dependent increase in vascular tension was still demonstrated by GAE although total tension was low. 4) GAE increased $Ca^{++}$ efflux from vascular smooth muscle cells, but have no effect on $Ca^{++}$ influx. 5) GAE increased $Ca^{++}$ efflux from sarcoplasmic reticulum and mitochondria vesicles. From the above results, it may be concluded that GAE increased the release of $Ca^{++}$ from sarcoplasmic reticulum, mitochondria or other intracellular $Ca^{++}$ stores of vascular smooth muscle, but it does not increase $Ca^{++}$ influx across the plasma membrane.