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( Yeon Hui Jeong ),( Jin Won Hyun ),( Tien Kim Van Le ),( Dong Hyun Kim ),( Hee Sun Kim ) 한국응용약물학회 2013 Biomolecules & Therapeutics(구 응용약물학회지) Vol.21 No.5
Microglial activation plays an important role in the development and progression of various neurological disorders such as cerebral ischemia, multiple sclerosis, and Alzheimer`s disease. Thus, controlling microglial activation can serve as a promising therapeutic strategy for such brain diseases. In the present study, we showed that kalopanaxsaponin A, a triterpenoid saponin isolated from Kalopanax pictus, inhibited inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and tumor necrosis factor (TNF)-α expression in lipopolysaccharide (LPS)-stimulated microglia, while kalopanaxsaponin A increased anti-infl ammatory cytokine interleukin (IL)-10 expression. Subsequent mechanistic studies revealed that kalopanaxsaponin A inhibited LPS-induced DNA binding activities of NF-κB and AP-1, and the phosphorylation of JNK without affecting other MAP kinases. Furthermore, kalopanaxsaponin A inhibited the intracellular ROS production with upregulation of anti-infl ammatory hemeoxygenase-1 (HO-1) expression. Based on the previous reports that JNK pathway is largely involved in iNOS and proinfl ammatory cytokine gene expression via modulating NF-κB/AP-1 and ROS, our data collectively suggest that inhibition of JNK pathway plays a key role in anti-infl ammatory effects of kalopanaxsaponin A in LPS-stimulated microglia.
Modeling and Simulation for PIG Flow Control in Natural Gas Pipeline
Nguyen, Tan-Tien,Kim, Sang-Bong,Yoo, Hui-Ryong,Park, Yong-Woo The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.8
This paper deals with dynamic analysis of Pipeline Inspection Gauge (PIG) flow control in natural gas pipelines. The dynamic behaviour of PIG depends on the pressure differential generated by injected gas flow behind the tail of the PIG and expelled gas flow in front of its nose. To analyze dynamic behaviour characteristics (e.g. gas flow, the PIG position and velocity) mathematical models are derived. Tow types of nonlinear hyperbolic partial differential equations are developed for unsteady flow analysis of the PIG driving and expelled gas. Also, a non-homogeneous differential equation for dynamic analysis of the PIG is given. The nonlinear equations are solved by method of characteristics (MOC) with a regular rectangular grid under appropriate initial and boundary conditions. Runge-Kutta method is used for solving the steady flow equations to get the initial flow values and for solving the dynamic equation of the PIG. The upstream and downstream regions are divided into a number of elements of equal length. The sampling time and distance are chosen under Courant-Friedrich-Lewy (CFL) restriction. Simulation is performed with a pipeline segment in the Korea gas corporation (KOGAS) low pressure system. Ueijungboo-Sangye line. The simulation results show that the derived mathematical models and the proposed computational scheme are effective for estimating the position and velocity of the PIG with a given operational condition of pipeline.