Cardiovascular Neurons Mediating Somatosympathetic Reflex in Rostral Ventrolateral Medulla

Goo,Yong-Sook,Kim,Sang-Jeong,Kim,Jun,Sung,Ho-Kyung 대한생리학회 1993 대한생리학회지 Vol.27 No.2

The rostral ventrolateral medulla (RVLM) includes vasopressor neurons, which transmit activation signals to the intermediolateral nucleus (IML) of the spinal cord, where the preganglionic sympathetic nucleus is located, to raise arterial blood pressure (BP). However, controversy exists as to the possible depressor area in the RVLM and the pathway involved. The present study persued evidence far the location of depressor neurons and the pathway by simultaneously observing changes in BP and the firing rate (FR) of cardiovascular neurons (CVNs) in the RVLM during the somatosympathetic reflex (SSR) elicited by peripheral nerve stimulation, since CVNs are known to contribute to the generation of the sympathetic nerve discharge. In 42 cats, anaesthetized with α-chloralose, single unit recording was performed, using carbon filament electrodes inserted into the RVLM, enabling estimation of the post R wave unit histogram (PR-UNlT) and the spike triggered average of sympathetic nerve discharge (STA-SND), allowing identification of CVNs. Antidromic stimulation of spinal T₂ segment was followed to determine whether the identified CVN projects axonal endings to the spinal cord (reticulospinal neuron). The sciatic nerve was electrically stimulated at AΔ-intensity (1 mA, 0.1 ms), 1 Hz and C-intensity (10 mA, 0.5 ms), 20 Hz to elicit the depressor, and pressor responses of the SSR, respectively. Simultaneous measurement of CVN firing rate was made. Experimental results are summarized as follows. 1) 20 out of 98 CVNs had axonal projections to the spinal cord and 17 out of 98 CVNs showed FR changes during SSR. 2) Response patterns of FR and BP during SSR were classified into 8 types. 3) These 8 different response patterns could be further classified into those from pressor and depressor neurons. These results demonstrate that some CVNs were identifiable as reticulospinal neurons responding to anti-dromic stimulation and that CVNs operating as depressor neurons as well as pressor neurons exist in the RVLM, both of which are involved with SSR mediation. Therefore, evidence was found that an independent depressor pathway might be involved in the mediation of SSR.

송욱 시에 나타난 자연과 생명

정효구(Hyo-goo, Jeong) 어문연구학회 2010 어문연구 Vol.63 No.-

This paper is written under the premises that Song Wuk’s four collections of poetry emlxxiy the idea of 'principle of Tao' and ‘body of Tao.’ and that their metonymy. wruch include nature. body. life and universe, are regarded as the focal point of comprehending and solving problems. Song Wuk is a poet who approached the process of writing as a highly intellectual attitude. However. it was trus attitude that made rum realize the limitations of the intellect. especially that of the Western culture. He then discovered that beyond the realm of intellect exist the fundmental principle that governs the world, which exists in the vital forms of life. nature, body and universe. Based on such discovery. his poems carry certain significance in the rustory of Korean poetry. First. far from merely being one of many contemporary poets, Song Wuk is one of those who follow the tradition of Korean poet such as Han Yong-Un. Sea Jeong- Ju, Jo Ji-Hun. Kim Gwan-Sik. whose works are based on the Asian idea of Tao. Second, the idea of Tao that he portrays in rus works sucessfully integrates the worlds of Taoism, Buddhsism and Yin and Yang. and focuses on the world of Taoism, nature rather than that of artificiality. This is the point where the idea of Tao embodied in his works diverts from that of Congucianism and Wang Yangming. Third Song Wuk's exploration of the nature, body, uniiverse, and life based on the idea of Tao coincides with the extensive discussions about our body and ecology that has taken place in Korea since 1990s. His poems are in effect their precedents that pioneered the movement. By uncovering such characteristics of Song Wuk's poetry, this paper will contribute to expanding the understanding of his works, which has mostly been confined to acknowledging his use of intellectual satires, ironies and experimental Ianguages. Furthermore, by acknowledging such nature of Song Wuk's poems, we can comprehend the complexity of his poems, and appreciate and assess them with a better structural understanding.

3G UMTS와 WLAN EAP인증 결합

정종민,이구연 강원대학교 정보통신연구소 2004 정보통신논문지 Vol.8 No.-

A next generation wireless system will be converged with a number of current wireless systems that have unique and individual features. These days, researches about the integration of a 3G cellular networks and NUN are fully activated. But they are not considered subject of the virtual home environment (VHE) and global roaming environment (GRE) which are defined for personal mobility in 3G wireless system. In the GRE and the VHE, there needs an authentication among different networks as well as between user equipment and access network. In this paper we deal with an extended authentication procedure which accepts the VHE and GRE of 3G wireless system regarding an integration of authentication between 3G cellular network and Wireless LAN.

실시간 온라인 네트워크 게임 환경에서의 게임 트래픽 특성 분석

정종민,이문규,이구연 강원대학교 산업기술연구소 2000 産業技術硏究 Vol.20 No.B

The study of game traffic has neglected by scientists, but as Internet gaming becomes more popular, multiplayer online games have become a significant element of Internet traffic. In this paper we analyze Internet traffic generated by sessions of multiplayer online games and study source models of multiplayer online game traffic. Our analysis shows that the empirical game traffic can be characterized by certain analytical model. We describe how our empirical traffic data set can be modeled and discuss how game server type influences interarrival distribution.

PKI 방식의 차세대 이동통신 망에 적용 가능한 인증서 검증 절차 설계

정종민,이구연 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

When the wireless PKI is applied to 3G/4G mobile network which requires mutual authentication among all entities, the wired PKI procedure is not feasible for validating visited network's certifications because of the wireless environmental limitations. Also, if we depend on WAP based PKI, we cannot support confidence about certification validation since the information offered from visited network is not authenticated. Therefore, in this paper we consider various and unique characteristics of mobile environment for certification validation at 3G/4G mobile networks based on wireless PKI and then propose two certification validation procedures.

연산 증폭기 (TL494) 를 이용한 DC/DC 승압 컨버터 제어 시스템 설계

정구종,이혜연,문경주,정유석,이준영,손영익 明知大學校 産業技術硏究所 2009 産業技術硏究所論文集 Vol.28 No.-

A simple control system using an op Amp (TL494) is presented for a DC/DC boost converter. The DC/DC boost converters have many industrial applications including renewable energy sources and hybrid automobiles. The problem of regulating the output voltage in the presence of load variation has been a research subject of interest for many years. After computer simulations with SimPower system of Matlab Simulink, we have developed the converter system in university laboratory according to the design specifications. Since the chip TL494 has both op Amp and PWM comparator even beginners can easily develop the control system. Experimental results show that the proposed system has some robustness with respect to the load variation.

쪼개진 환형 안테나의 전류 밀도 및 복사 패턴 해석

정구철 한국기술교육대학교 2003 論文集 Vol.10 No.1

During the past several years, the advancement design has been characterized by an exhaustive utilization of antenna geometry. In the study of antenna theory, a knowledge of the current distribution is of fundamental importance. Such data may be obtained either by measurement or by solving the antenna integral equation. Integral equations are difficult to solve even for the simplest case of a dipole antenna. In conventional formulation of antenna problem, an integral equation for the antenna current distribution is derived by forcing the component of the scattered electric field tangential to the antenna surface to cancel the corresponding of the incident field over the antenna surface. In this paper cleaved circular Antenna fed by coaxial cable is described to obtain current density in the various environments. To illustrate the use of presented formulation method of integral equations it is applied to the cleaved circular Antenna. Also, the current density induced by an incident plane wave illumination are obtained for the cleaved circular Antenna. In order to approximate the circular antenna to cylindrical antenna, radius of the circular antenna is increased and a parameter Ф is made very small.

염산 메트폴민을 함유하는 경구방출제어형 제제의 제조 및 용출특성

구본철,김정수,이계원,지웅길 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

Metformin is an antihyperglycemic agent of the biguanide class used in the treatment of non-in-sulin-dependent diabetes mellitus. Metformin hydrochloride has intrinsically poor permeability in the lower portion of the GI-tract leading to absorption almost exclusively in the upper part of the GI-tract. Its oral bioavailability is in the range of 50 to 60%. It also has a very high water solubility. In this study, we prepared sustained release matrix system containing metformin hydrochloride using various characteristics of polyethylene oxide (PEO). The metformin hydrochloride matrix tablets were prepared by direct compressed method and wet granulation compressed method with various molecular weight of PEO. Even though the molecular weights of PEOs used were 900K, 2,000K, and 5,000K. Moreover, three types of matrix tablets were formulated compositions were same, the hardness was different. The release kinetics were studied for 9 hours in pH 1.2 simulated gastric fluid and pH 6.8 simulated intestinal fluid, using a dissolution tester at 37.5℃, 50 rpm. As the molecular weight of PEO increased, the release rate decreased due to the slower swelling and dissolution of PEO. For the effect of hardness of matrix tablets, the rate of drug release was decreased with increasing hardness.

ISDN AO/DI 시스템에서 버퍼링 기능 구현으로 인한 성능 향상

정종민,이구연 강원대학교 산업기술연구소 2000 産業技術硏究 Vol.20 No.B

ISDN AO/DI provides efficient communication. It dynamically allocates channels for bandwidth, which is key component for packet data communication. In this paper, we analyze performance improvement of ISDN AO/DI system with buffering scheme and compare with AO/DI system without buffering scheme. From the simulation of AO/DI with buffering scheme, we see that the required bandwidth is less than of the AO/DI system without buffering scheme.

가입자 정보보호를 위한 Virtual Home Environment 시나리오 보안 취약점 분석

정종민,이구연,이용 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.A

Currently, the VHE (suggested for global roaming user to provide personal service environment) implementation scenario is being proposed to realize 3G network requirements. However, developing VHE scenarios are focused on signal flew between node and network, and network and network. this case may result in weakness to protect subscriber's privacy in 3G network which commonly uses visited network. In this paper, we reanalyze a several VHE implementation scenarios for user profile protection, indicate a problem concerning user privacy, and finally, design a procedure to cope with vulnerability in VHE implementation scenario.