• Proceedings of the Ginseng society Conference
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• 2004.12a
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• pp.7-11
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• 2004

We previously reported that ginseng inhibited NMDA receptors in cultured hippocampal neurons. Here, we further examined the detailed mechanism of ginseng-mediated inhibition using its main active ingredient, ginsenoside Rg$_3$. Co-application of ginsenoside Rg$_3$ with increasing concentrations of NMDA did not change the EC$_{50}$ of NMDA to the receptor, suggesting ginsenoside Rg$_3$ inhibits NMDA receptors without competing with the NMDA-binding site. Ginsenoside Rg$_3$-mediated inhibition also occurred in a distinctive manner from the well-characterized NMDA receptor open channel blocker, MK-801, However, ginsenoside Rg$_3$ produced its effect in a glycine concentration-dependent manner and shifted the glycine concentration-response curve to the right without changing the maximal response, suggesting the role of ginsenoside Rg$_3$ as a competitive NMDA receptor antagonist. We also demonstrated that ginsenoside Rg$_3$ significantly protected neurons against NMDA insults. Therefore, these results suggest that ginsenoside Rg$_3$ protects NMDA-induced neuronal death via a competitive interaction with the glycine-binding site of NMDA receptors in cultured hippocampal neurons.

• Elastomers and Composites
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• v.51 no.3
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• pp.233-239
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• 2016

Polyethylene (PE) and maleic anhydride-grafted PE (PE-g-MAH) were pyrolyzed, and their pyrolysis products were analyzed using gas chromatography/mass spectrometry (GC/MS) to investigate the influence of MAH grafted onto PE on pyrolysis behaviors. Major pyrolysis products of PE and PE-g-MAH were n-alkanes, 1-alkenes, ${\alpha},{\omega}$-alkadienes, and aromatic compounds. 1-Alkenes were more formed than n-alkanes, ${\alpha},{\omega}$-alkadienes, and aromatic compounds. Butadiene was more produced from PE than PE-g-MAH, whereas toluene and ethyl benzene were more generated from PE-g-MAH than PE. Difference in the pyrolysis behaviors between PE and PE-g-MAH were explained by initial decomposition of MAH moiety.

• Journal of the Korean Chemical Society
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• v.14 no.2
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• pp.161-168
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• 1970

In order to obtain the more effective evidence, supporting the hypothesis which have been previously described by former report that pepsin (EC 3.4. 4.1) forms a hydrophobic bond with the nonpolar side chain of its substrate, the inhibitory effect of carboxylic acids(from formic acid to iso-butyric acid) on the activity of pepsin to the synthetic dipeptide, N-Carbobenzoxy-L-glutamyl-L-tyrosine, was discussed. The kinetic study showed that the inhibition by carboxylic acids was competitive. The Kidecreased with increasing size of the inhibitor molecule. The $-{\Delta}F^{\circ}$increased linearly with increasing number of carbon atoms in the hydrocarbon chain of the inhibitor. It was confirmed that the hydrophobic bond between more than one side chain of amino acid residues(phenylalanine) in the binding region of the active center of pepsin and the side chain of amino acid residues in the substrate was formed as the first step of its enzymic mechanism. The inhibitory effect of carboxylic acids was due to the competition of the hydrocarbon group of the carboxylic acids with the side chain of the substrate for the hydrophobic binding site(the side chain of phenylalanine) of the pepsin.

• Elastomers and Composites
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• v.55 no.1
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• pp.6-12
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• 2020

Poly(ethylene-co-vinyl acetate) compounds and vulcanizates containing dicumyl peroxide (DCP) (HD) were prepared, and the curing agent and reaction products were analyzed using gas chromatography/mass spectrometry (GC/MS). Samples containing trially cyanurate (TAC) and DCP (HDT) were also prepared and analyzed. Some raw DCP were decomposed in the injector region of GC to produce acetophenone. DCP was detected in the HD compound but was not observed in the HD vulcanizate, and instead acetophenone and 2-phenyl-2-propanol were detected. Both DCP and TAC were observed in the HDT compound but not in the HDT vulcanizate, where acetophenone and 2-phenyl-2-propanol were detected. Thus, some of the DCP decomposed during the compounding process. The formation mechanism for acetophenone and 2-phenyl-2-propanol during the crosslinking reaction was identified, and differences in the crosslinking reactions of HD and HDT compounds were discussed.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.74-77
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• 2004

Porous membranes were prepared via thermally induced phase separation (TIPS) of (ethylene-co-vinyl alcohol) (EVOH)/glycerol mixtures. The liquid-liquid (L-L) phase boundaries are shifted to higher temperature when the ethylene contents in EVOH increase. Moreover, the kinetic study proved that the growth of droplets formed by the general liquid-liquid (L-L) phase separation obeyed a power-law scaling relationship in the later stage of spinodal decomposition (SD). A new phase separation mechanism was presented, in which the L-L phase separation could be resulted from the crystallization. The hollow fiber membranes were prepared. The membranes showed asymmetric structures with skin layer near the outer surface, the larger pores just below the skin layer and the smaller pores near the inner surface. The effect of ethylene content (EC) in EVOH, cooling water bath temperature and take-up speed on membrane performance was investigated.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.169-171
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• 2005

현재 IEEE 802.15.4(Low-Rate WPAN)를 구성하는 디바이스들은 파워, 메모리 용량, 연산처리 등의 물리적 제약으로 인해 보안을 위한 공유키 생성은 대칭키 기반의 메카니즘을 사용하고 있다. 그러나 대칭키 기반 메카니즘은 키 관리, 키 분배, 디바이스의 이동성지원과 같은 부분에 문제점을 가지게 된다. 또한 LR-WPAN 환경은 해당 어플리케이션에 따라 차별된 보안 정책을 가질 수 있으며, 디바이스의 물리적 상태에 따라 보안강도를 결정하는 경우도 발생할 수 있다. 본 논문에서는 타원곡선 기반의 EC-MQV 알고리즘을 사용하여 공개키 기반의 공유키 생성 메카니즘을 제안한다. 또한, 코디네이터를 활용하여 각 디바이스의 연산을 최소화하여 디바이스의 에너지 소비를 줄이는 방법을 제시하고, 보안 레벨에 따른 키 생성에 관하여 설명한다.

• The Plant Pathology Journal
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• v.26 no.4
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• pp.380-385
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• 2010

Suppression subtractive hybridization was used to isolate wound-induced genes from soybean. One of the wound-induced genes, gmwi143 designated as GmCCR, showed high homology with genes encoding cinnamoyl-CoA reductase (CCR; EC 1.2.1.44). Deduced amino acid sequences encoded by GmCCR showed the highest identity (77%) with those of Acacia CCR. There are 2 CCR genes highly homologous to GmCCR in soybean genome based on Phytozome DB analysis. RNA expression of GmCCR was specifically induced by local and systemic wounding, drought, high salinity or by ultraviolet stress. Our study suggests that GmCCR may be involved in resistance mechanism during abiotic stresses in plants.

• Journal of Information Technology Services
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• v.4 no.2
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• pp.79-97
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• 2005

With the proliferation of EC, many customers have been participating into online auction or group-buying market over searching internet shopping-malls to purchase goods. To support the customer's convenient transaction, lots of agent systems are developed to facilitate the customer's product brokering, merchant brokering, and negotiation of transaction. However, many of these systems have focused upon supporting transaction at only one type of marketplace. Since these marketplaces have different transaction settlement mechanism, it is necessary to develop the system that utilizes the customer's transaction including the selection of the type of marketplace to buy. Then we classify the kinds of B2C electronic marketplace according to the protocol by which the market operated. The structure of negotiation message is developed using XML schema and RDFS under the characteristics and message example of each marketplace in this research.

• Archives of Pharmacal Research
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• v.15 no.2
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• pp.146-151
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• 1992

The aim of this study was to evaluate capability of pertussis toxin (PT) to active mouse macrophages. The investigations were undertaken to determine whether the role played by this toxin required the A-protomer of the toxin to ADP-ribosylate a guanine nucleotide binding protein (a class I activity) or was dependent on the binding of B-oligomer of the toxin to the surface of target cells (a Class II activity). The results of these experiments have established that the mechanism of macrophage activation with PT seems to be dependent upon a Class II activity of the toxin.

• Bulletin of the Korean Chemical Society
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• v.16 no.4
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• pp.321-325
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• 1995

Adsorption mechanisms of diisobutyl dithiophosphinate (DIBDTPI) and diisobutyl monothiophosphinate (DIBMTPI) on gold and gold-silver alloys (80:20 and 50:50) have been studied. The adsorption mechanisms on gold-silver alloys can be explained by the EC mechanism involving an electron transfer step and a chemical reaction step. Thus, the adsorption should be controlled by the E of the electrochemical oxidation of the electrode involved and the pK of the metal collector complex. Both di- and mono- thiophosphinate adsorb on 50:50 Au-Ag alloy at lower potential than on 80:20 Au-Ag alloy surface. There are no significant differences between the reactivities of DIBDTPI and DIBMTPI with precious metals except that the dithio- compound can be oxidized to dimer on gold at high potentials, while the monothio- homologue cannot. In this regard, DIBDTPI may be a better surface active reagent for pure gold than DIBMTPI.