• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.337-339
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• 2003

NGN 시대가 될수록 이동성을 지원하면서 네트워크를 효율적으로 이용하는 기술이 요구된다. Mobile Ipv6은 이와 같은 요구조건을 만족시키는 좋을 방법이다. 본 논문에서는 이동호스트가 핸드오버를 수행할 때 발생하는 Triangle Routing 오버헤드를 감소시키는 핸드오버 프로토콜을 제안한다. 제안된 핸드 오버 프로토콜은 Previous Access Router(PAR)가 Binding Update(BU) 메시지를 전송하게 함으로써 PAR에서 New Access Router(NAR)로 포워딩되는 패킷의 개수를 감소시킨다. 제안된 핸드오버는 NS-2(network simulation)에서 시뮬레이션 되었고, 멀티미디어 데이터 통신에 사용되는 UDP를 이용하였다.

• 대한치과교정학회:학술대회논문집
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• 2000.11a
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• pp.42.2-42.2
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• 2000

• Journal of the Society of Naval Architects of Korea
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• v.37 no.3
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• pp.57-68
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• 2000

The Power Augmented Ram(PAR) effect, which blows the down stream of the propellers into the underside of the wings and hence increases the pressure between the lower surface of the wings and the sea surface, is known significantly to enhance the performance of the WIG concept by reducing the take-off and landing speeds. The aerodynamic characteristics of a 20 passenger PARWIG are investigated by wind tunnel tests with the 1/20 scale model. The efflux of the forward mounted propellers are simulated by jet flows with a blower and duct system. The lift, drag, and pitch moment of the model with various ground clearances, angles of attack and flap angles are measured for the various jet velocities, jet nozzle angles, horizontal and vertical positions of the nozzle, and the nozzle diameters. The aerodynamic characteristics of the PARWIG due to these parametric changes are compared and pertinent discussions are included. It is shown that the proper use of the PAR can increase the lift coefficient of as much as up to 4.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.6
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• pp.1617-1621
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• 2004

The aim of this study was to investigate the apoptotic effect and its mechanism on Radix Paeoniae Alba Extract(RPAE) in DU145 human prostate cancer cell line. RPAE induced apoptosis in a dose-dependent manner in DU145 cells as confirmed by both discontinuous DNA fragmentation using Hoechst33342 staining and poly-(ADP-ribose) polymerase(PARP) cleavage, which are apoptotic signs. To clarify the mechanisms on RPAE-induced apoptosis, we examined the p50(NF-κB subunit), IκBα, PTEN and Par-4 protein expression using Western blotting. Treatment with RPAE resulted in the decrease of p50 expression by IκBα increase, which resulted in Par-4 increase and bcl-2 decrease in DU145 cells. These results suggest that apoptosis of DU145 cells by RPAE involved decreases of NF-κB activation and bcl-2 expression, increase of Par-4 protein expression.

• Natural Product Sciences
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• v.11 no.4
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• pp.207-212
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• 2005

Tetragonia tetragonoides (Aizoaceae) has been known as an anti-cancer agent. The activation of proteinase-activated receptor-2 (PAR-2) by trypsin appears to play a role in inflammation. In the present study, we examined the inhibitory effects of Tetragonia tetragonoides water extract (TTWE) on the production of tumor necrosis $factor-{\alpha}\;(TNF-{\alpha})$ and tryptase in trypsin-stimulated human leukemic mast cells (HMC-1) expressing PAR-2. HMC-1 cells were stimulated with trypsin in the presence or absence of TTWE (10, 100, and $1000\;{\mu}g/ml$). The level of $TNF-{\alpha}$ secretion from HMC-1 cells was measured by enzyme-linked immunosorbent assay (ELISA). $TNF-{\alpha}$ and tryptase mRNA expression were examined by reverse transcription-PCR. Also, extracellular signal-regulated kinese (ERK) activation was assessed by Western blot analysis. Trypsin activity was measured using the substrate Bz-DL-Arg-p-nitroanilide (BAPNA). It was observed that $TNF-{\alpha}$ secretion, tryptase mRNA and $TNF-{\alpha}$ mRNA expression in trypsin-stimulated HMC-1 cells were inhibited by pretreatment of TTWE ($1000\;{\mu}g/ml$). Furthermore, the pretreatment of TTWE ($1000\;{\mu}g/ml$) resulted in the reduction of ERK phosphorylation and trypsin activity. These results suggest hat TTWE might have the inhibitory effects on the PAR-2-dependent inflammation processes and it is likely to function as PAR-2 antagonist.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.222-228
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• 2001

Vibrio metschnikovii strain RH530 is a non-pathogenic, industrially-important alkaline protease producer which has been isolated from wastewater. In this paper, we report on the transformation of this strain by using the method of electroporation. A field strength of $7.5\;kVcm^{-1}$ and $25\;{\mu}F$, and using a 0.2-cm cuvette, appeared to be the optimal conditions for electroporation of the cells with the recombinant pSBCm plasmid carrying the vapK alkaline protease gene and the ColE1 replicon. Cells were subjected to osmotic shock in order to remove extracelluar DNase, and adding 200 mM of sucrose to electroporation buffer cells showed an increased transformation efficiency. Maximum efficiency of transformation was obtained at an early exponential growth phase. Using all of the conditions mentioned above, we routinely obtained a transformation efficiency of more than $10^4{({\mu}g\;plasmid\;DNA)}^{-1}$. The stability of the plasmid pSBCm in V. metschnikovii RH530 was 25% after 18h of growth (27 generations) in the medium without antibiotic selection. The insertion of the par locus to the pSBCm increased the stability of the plasmid up to 42% without selective pressure. The increase in plasmid stability was accompanied by the increase in the productivity of alkaline protease in the recombinant V. metschnikovii strain RH530. Determining optimal conditions for the transformation of the industrially-important, nonpathogenic Vibrio strain, and the improvement of plasmid stability by introducing the par locus into the high copy number plasmid vector, will allow the development of procedures involved in the genetic manipulation of this strain, particularly for its use in the production of industrial enzymes such as alkaline protease.

• The Journal of Information Systems
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• v.13 no.2
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• pp.22-48
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• 2004

Information systems that are not used cannot be useful. In order to increase user acceptance, it is necessary to understand why people accept or reject information systems. Technology Acceptance Model(TAM) is one of the most influential research models for studying determinants how users accept information systems. Recently, Knowledge Management Systems(KMS) have become important components of corporate systems as the foundation of industrialized economics has shifted from natural resources to knowledge assets. This paper applies TAM to investigate users' acceptance of KMS in public administration institutions. It sampled 182 users who had experience in using KMS. Many empirical researches have suggested that TAM can be integrated with other organizational theories to improve its predictive and explanatory ower. We extended the basic TAM by the integration of appraisal and reward satisfaction theory. There are many external variables that influence the perception and the belief of system users. We introduced two external variables(job characteristics, IT self-efficacy) and one additional perception variable, perceived appraisal and reward(PAR) in the basic TAM model. The LISREL model analysis is used for finding out the causality among variables and testing the model fitness. As result, The IT self-efficacy influences to the perceived ease of use(PEOU) and the PAR, and the PEOU influences directly to the perceived usefulness(PU), the PAR, and the attitude toward KMS. The KMS participation intention(PI) was influenced by the PAR and the attitude directly,andbythePEOUindirectly. Finally, this paper suggests some guidelines for the adoption of KMS in public sectors on the basis of the study results.

• YAKHAK HOEJI
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• v.41 no.2
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• pp.247-254
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• 1997

The proteinase-activated receptor (PAR-2) belongs to the family of seven transmembrane region receptors, like the thrombin receptor, it is activated by specific proteolytic clea vage of its extracellular amino terminus and a synthetic peptide (SLIGRL). The earthworm protein fraction (EPF) extracted from Lumbricus rubellus elicted dose- and endothelium-dependent relaxations in phenylephrine-contracted rat thoracic aorta, whereas heat inactivated EPF (0.5 ${\mu}g$ /ml) had no effect. In the presence of the nitric oxide synthase inhibitor NG-methyl-L-arginine (1.8 micro M), EPF (0.5 ${\mu}g$ /ml)-induced relaxations were partially inhibited. Furthermore, EPF (0.5 ${\mu}g$ /ml) dramatically caused relaxation of thrombin-desenstized rat thoracic aorta. These results indicate that EPF activates PAR-2 in vascular endothelial cell. Intravenous injection of EPF (20 mg/kg, bolus) into anesthetized rats produced a marked depressor response. EPF (0 ~ 80 ${\mu}g$ /ml, gradient) was very effective on increasing of perfusion volume in rabbit ear vessel preparations. These results imply the usefulness of EPF as a vascular smooth muscle relaxant and indicate that the activation of PAR-2 may be a mechanism of EPF on hemokinetic improvement.

• KSBB Journal
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• v.25 no.1
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• pp.11-17
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• 2010

Here, we evaluated the effect of thrombin on the interleukin-6 production induced by tumor-necrosis-factor-$\alpha$ in endothelial cells. It is well known that tumor-necrosis-factor-$\alpha$ mediates inflammatory responses by activation of nuclear factor-kappa-B in endothelial cells. Here, we showed that lower concentration of thrombin decreased the production of interleukin-6 induced by tumor-necrosis-factor-$\alpha$ and this inhibitory effect of thrombin on interleukin-6 production was mediated by interacting with protease-activated-receptor-1. In addition, phosphoinositide-3-kinase was also involved the anti-inflammatory responses by lower concentration of thrombin in endothelial cells. These results suggested that lower concentration of thrombin mediated anti-inflammatory responses by interacting with protease-activated-receptor-1 on the cell membrane and phosphoinositide-3-kinase in the cell. These findings will provide the important evidence in the development of new medicine for the treatment of severe sepsis and inflammatory diseases and good clue for understanding unknown mechanisms by which thrombin showed the pro-inflammatory or anti-inflammatory activities in endothelial cells.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.455-459
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• 2007

Plasma catalytic methane conversion was carried out in the presence of sol-gel derived $Pt/TiO_2$ catalysts within a dielectric-barrier discharge (DBD) reactor. Plasma-assisted reduction (PAR) was applied to reduce the prepared $Pt/TiO_2$ catalysts in DBD reactor, and prepared catalysts were successively reduced by PAR within 20 min irrespective of the Pt loading and the calcination temperature. The highest methane conversion was 40% when 3 wt% $Pt/TiO_2$ and 5 wt% $Pt/TiO_2$ catalysts were used after calcination at $600^{\circ}C$. The selectivities of light alkanes ($C_2H_6$, $C_3H_8$, $C_4H_{10}$) were highly increased when $Pt/TiO_2$ catalysts were used in DBD reactor.