• Journal of Ginseng Research
• /
• v.36 no.1
• /
• pp.47-54
• /
• 2012

Korean red ginseng (KRG) has been used worldwide as a traditional medicine for the treatment of various reproductive diseases. Gonadotropin releasing hormone (GnRH) neurons are the fundamental regulators of pulsatile release of gonadotropin required for fertility. In this study, an extract of KRG (KRGE) was applied to GnRH neurons to identify the receptors activated by KRGE. The brain slice patch clamp technique in whole cell and perforated patch was used to clarify the effect of KRGE on the membrane currents and membrane potentials of GnRH neurons. Application of KRGE (3 ${\mu}g$/${\mu}L$) under whole cell patch induced remarkable inward currents (56.17${\pm}$7.45 pA, n=25) and depolarization (12.91${\pm}$3.80 mV, n=4) in GnRH neurons under high $Cl^-$ pipette solution condition. These inward currents were not only reproducible, but also concentration dependent. In addition, inward currents and depolarization induced by KRGE persisted in the presence of the voltage gated $Na^+$ channel blocker tetrodotoxin (TTX), suggesting that the responses by KRGE were postsynaptic events. Application of KRGE under the gramicidin perforated patch induced depolarization in the presence of TTX suggesting its physiological significance on GnRH response. Further, the KRGE-induced inward currents were partially blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; non-NMDA glutamate receptor antagonist, 10 ${\mu}M$) or picrotoxin (PIC; $GABA_A$ receptor antagonist, 50 ${\mu}M$), and almost blocked by PIC and CNQX mixture. Taken together, these results suggest that KRGE contains ingredients with possible GABA and non-NMDA glutamate receptor mimetic activity, and may play an important role in the endocrine function of reproductive physiology, via activation of $GABA_A$ and non-NMDA glutamate receptors in GnRH neurons.

• The Korean Journal of Pharmacology
• /
• v.29 no.1
• /
• pp.107-120
• /
• 1993

Particulate or soluble stimuli appear to stimulate phagocytic cell's response by the change of $Ca^{2+}$ mobilization and by the activation of protein kinase C. In contrast, it is reported that activation of protein kinase C could attenuate agonist-stimulated elevation of $Ca^{2+}i$ in neutrophils. PAF elicited an increase of $Ca^{2+}i$ in peritoneal macrophages in a dose dependent fashion and $Ca^{2+}$ extrusion was accompanied. PAF-induced elevation of $Ca^{2+}i$ was not affected by TMB-8, verapamil and TTX. TEA stimulated PAF-induced mobilization of $Ca^{2+}i$ and delayed lowering of $Ca^{2+}i$. Five mM EGTA almost completely inhibited PAF-induced mobilization of $Ca^{2+}i$. After the addition of PAF, membrane permeability was markedly increased up to 5 min and then slowly increased. PAF-induced LDH release was slightly decreased by EGTA plus TMB-8. PAF-stimulated superoxide generation was inhibited by EGTA, TMB-8 and verapamil but not affected by TTX and TEA. PAF-induced elevation of $Ca^{2+}i$, increased membrane permeability and superoxide generation were inhibited by IQSP, chlorpromazine and propranolol. PAF-induced LDH release was significantly inhibited by chlorpromazine and minimally decreased by propranolol. After the pretreatment with PMA, the stimulatory effect of PAF on the elevation of $Ca^{2+}i$ and LDH release in macrophages was significantly decreased. These results suggest that PAF may exert the stimulatory action on peritoneal macrophages of mouse by the elevation of $Ca^{2+}i$ and by the activation of protein kinase C. Preactivation of protein kinase C appears to attenuate the stimulatory action of PAF on macrophage response.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1-6
• /
• 2011

In Korea, high-speed train(HEMU-400X) system with distributed power is being developed, and the highest test speed of this train is 400km/h. This developed the first high-speed train as a distributed power train in Korea, as well as for the development of train system and evaluation system included evaluation technology is needed. Accordingly, a comprehensive and efficient OMS(Overall Measurement System) was build up for verifying the performance of HEMU-400X. By the case study of the G7 and TTX, OMS of HEMU-400X was improved the test performance and maintainability. In particular, the existing Window-based systems has a limit to the control, due to this reason OMS applying enhanced RT(Real-time) system. In this study, compare the advantages and disadvantages of RT systems with Window-based systems, as well as the configuration of the RT systems.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.6
• /
• pp.807-815
• /
• 2004

In order to evaluate the static stability of hybrid carbody structures of Korean Tilting Train eXpress(TTX) caused by degradation of composites under ground environments, T300/AD6005 graphite/epoxy composite specimens were exposed to accelerated environmental conditions including ultraviolet radiation, temperature and moisture fer 2000 hours. It was found that the stiffness and strength of composites after aging were lower than those of unexposed specimens, and decreased as the aging time increases. The values of the degraded properties were used in the static analysis to check the static stability of hybrid carbody structures caused by environmental degradation of composites. The results shown that the structural stability of hybrid carbody structures was affected by the degradation of composites after exposure to accelerated aging environments.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.04a
• /
• pp.199-202
• /
• 2005

This study has performed the static loading tests for the composite train body of Korean tilting train. The structural tests based on the JIS E7105 standard were carried out in the test facility designed for the train carbody. The vertical, compressive and torsional loads were imposed on the underframe and the end structure of the carbody. the structural behavior of the carbody under the 3-point supporting and the natural frequency were evaluated as well. In addition, the test results were compared with the numerical one. From the tests. the structural strength of the hybrid composite carbody was assessed.

• Proceedings of the KIEE Conference
• /
• 2006.10d
• /
• pp.250-252
• /
• 2006

In this paper, we studied for the measurement system for on-line testing and evaluation of tilting train express(TTX). The measurement system is installed in each train for the performance measurement during the test run. It is composed of software part, hardware part and can measure various signals such as velocity, voltage, temperature. The software controls the hardware of the measurement system, performs the analysis and calculation of measurement data and acts as interface between users and the system hardware. The hardware is consisted of 7 DAMs(Data Acquisition Modules) and 6 monitoring modules.

• Proceedings of the KIEE Conference
• /
• 2008.11a
• /
• pp.494-496
• /
• 2008

Tilting train has been developed to increase the operational speed of the trains on conventional lines which have many curves. This train are tilted at curves to compensate for unbalanced carbody centrifugal acceleration to a greater extent than compensation produced by the track cant so that passengers do not feel centrifugal acceleration and thus trains can run at higher speed at curves. This paper developed tilting train to evaluate electromagnetic interference(EMI) performance of TTX(tilting train express) with maximum operation speed 160 km/h on Ho_nam Conventional Rail[1].

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.804-810
• /
• 2004

Tilting train can pass curve at higher speed without affecting passenger comfort by tilting Carbody. But the centrifugal force proportional to square of velocity increases the track lateral force. This is the one of the problems to be solved when applying tilting train. The one countermeasure we selected the light weight design by applying distributed traction EMU system and light weight materials such as FRP. The other countermeasure was to adopt steering bogie concept in order to reduce the guiding force on Curve track. This paper describes the design study of self steering mechanism applied to the Bogie for 180 km/h Korean Tilting Train(TTX), which was done as a part of the Korean National R&D project.

• 시스템엔지니어링워크숍
• /
• s.1
• /
• pp.9-14
• /
• 2003

The paper aims at presenting a systematic approach process and a method of requirement validation and system verification. Validation is applied during concept development to ensure conceptual validity, requirements validity, and design validity. Verification work is applied subsequent to the design work on test articles and early production items to produce evidence that the design solutions do, in fact, satisfy th requirements. In this paper, we present a requirements validation model and a system verification model. This models are applied to the development of TTX(Tilting Train Express)system with systems engineering tool, CORE.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.10a
• /
• pp.185-188
• /
• 2004

Regarding some of the components of the Korean Tilting Train eXpress(TTX), the lightweight-vehicle development was mainly focused to this study, and so as using the materials, the existing material, steel or aluminum carbody was changed to the composite carbody with both design and manufacturing methods. Therefore the evaluation of the performance of joint strength between composite and metallic boundary area, especially the under frame and the carbody was required, and the compressive and the bending tests were conducted as the sub-scale specimen. In this evaluation, there was involved the sufficient strengths at the joint area between the underframe and the carbody, and is resulted as the increment of the safety factor through the observation of failure conditions.