• Journal of Applied Biological Chemistry
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• 제51권2호
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• pp.45-49
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• 2008

Cytosolic fructose-1,6-bisphosphatase (cFBPase) in plants is a key regulatory enzyme in the photosynthetic sucrose biosynthesis. Plant cFBPases, like the mammalian FBPases, are inhibited by adenosine 5'-monophosphate (AMP) and fructose-2,6-bisphosphate (Fru-2,6-$P_2$). In the mammalian FBPases, Lys112 and Tyr113 play important roles in the AMP binding. To understand roles of the corresponding residues, Lys115 and Tyr116, in pea cFBPase, the mutant cFBPases were generated by site-directed mutagenesis. The alterations of Lys115 to Gin and Tyr116 to Phe displayed small changes in $K_m$ and $K_i$ for Fru-2,6-$P_2$, indicating that the mutation causes minor effects on the enzyme catalysis and Fru-2,6-$P_2$ binding, whereas resulted in higher than 500-fold increase of $[AMP]_{0.5}$ compared with that of the wild-type enzyme. Results indicate the residues Lys115 and Tyr116 play important roles in the binding of AMP to the allosteric site of the pea cFBPase.

• 대한한의학회지
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• 제21권4호
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• pp.193-203
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• 2000

Objectives : Hindered barrier function of vascular endothelium has been implicated in the initiation and progression of degenerative vascular diseases such as atherosclerosis. In this study, the effect of Sunghyangchungisan(SHCS) as a protectant against oxidant-induced destruction of endothelial barrier function was assessed. Methods : Toward this end, endothelial cells derived from the human umbilical vein were cultured as monolayers on permeable membrane filters. Endothelial permeability was monitored by measuring transendothelial electrical resistance and movement of low density lipoprotein (LDL) across the endothelial monolayer. Results : Along with increased movement of LDL, $H_2O_2$-induced increase in endothelial permeability was paralleled by a decrease in transendotheliaI electrical resistance. The effect of $H_2O_2$ was mimicked by phorbol 12-myristate 13-acetate (PMA), a potent activator of proteinkinase C. Calphostin-C, a protein kinase C inhibitor, effectively blocked the increase in endothelial permeability induced by $H_2O_2$ or PMA, indicating that activation of protein kinase C is associated with the $H_2O_2-induced$ permeability change. SHCS effectively protected the endothelial monolayer against $H_2O_2-induced$ increase in permeability, whereas, it did not affect PMA-induced change. Forskolin, a potent activator of adenylyl cyclase, antagonized $H_2O_2$ to increase endothelial permeability. In addition, in ${H_2O_2}-treated$ cens, intracenular cAMP concentration was significantly decreased, indicating that impaired cAMP production as well as activation of proteinkinase C is a mechanism underlying ${H_2O_2}>-induced$$H_2O_2$ with regard to its effect on intracellular cAMP content. However, SHCS itself did not affect resting cAMP concentration in endothelial cells. Conclusions : These results suggest that SHCS might operate as an effective protectant against oxidant-induced destruction of endothelial barrier function. The mechanism does not appear to involve direct interaction with protein kinase C- or cAMP-associated signaling mechanism.

• Journal of Microbiology and Biotechnology
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• 제25권7호
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• pp.1154-1162
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• 2015

The emergence of carbapenem resistance among Pseudomonas aeruginosa is an increasing problem in many parts of the world. In particular, metallo-$\beta$-lactamases (MBLs) and AmpC $\beta$lactamases are responsible for high-level resistance to carbapenem and cephalosporin. We studied the diversity and frequency of $\beta$-lactamases and characterized chromosomal AmpC $\beta$lactamase from carbapenem-resistant P. aeruginosa isolates. Sixty-one carbapenem-resistant P. aeruginosa isolates were collected from patients in a tertiary hospital in Daejeon, Korea, from January 2011 to June 2014. Minimum inhibitory concentrations (MICs) of four antimicrobial agents were determined using the agar-dilution method. Polymerase chain reaction and sequencing were used to identify the various $\beta$-lactamase genes, class 1 integrons, and chromosomally encoded and plasmid-mediated ampC genes. In addition, the epidemiological relationship was investigated by multilocus sequence typing. Among 61 carbapenem-resistant P. aeruginosa isolates, 25 isolates (41.0%) were MBL producers. Additionally, 30 isolates producing PDC (Pseudomonas-derived cephalosporinase)-2 were highly resistant to ceftazidime (MIC₅₀ = $256{\mu}g/ml$) and cefepime (MIC₅₀ = $256{\mu}g/ml$). Of all the PDC variants, 25 isolates harboring MBL genes showed high levels of cephalosporin and carbapenem resistance, whereas 36 isolates that did not harbor MBL genes revealed relatively low-level resistance (ceftazidime, p < 0.001; cefepime, p < 0.001; imipenem, p = 0.003; meropenem, p < 0.001). The coexistence of MBLs and AmpC $\beta$-lactamases suggests that these may be important contributing factors for cephalosporin and carbapenem resistance. Therefore, efficient detection and intervention to control drug resistance are necessary to prevent the emergence of P. aeruginosa possessing this combination of $\beta$-lactamases.

• 한국정보통신학회논문지
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• 제9권2호
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• pp.262-267
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• 2005

본 논문에서는 여러 가지 효율 개선 방법 중에서 Doherty Amplifier에 관해 논하였다. 간단한 회로를 이용하여 하나의 PEP 180w급 LDMOS를 사용하여 효율성과 선형성 개선에 관한 성능분석을 하였다 제작된 Doherty Amp의 성능을 검증하기 위해 Balanced Class AB Amplifier와 성능을 비교하였다. 실험결과 peaking Amp의 $V_gs.P$가 1.53V일 때 효율이 최대 11.6$\%$ 이상 증가되었으며 매뉴얼로 gate bias 조절을 통하여 선형성 개선의 최적 bias point를 찾은 후 WCDMA 4fA에서는 $V_gs.P$가 3.68V일 때 IMSR (InterModulation to Signal Ratio)이 최대 3.34dB가 증가됨을 보였다. 특히 1.53V로 peaking amp의 bias point를 맞추게 되면 출력 전력 434Bm에서 -324Bc 이하의 IMSR과 탁월한 효율 증가를 얻을 수 있었다.

• IMMUNE NETWORK
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• 제4권2호
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• pp.100-107
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• 2004

Background: The fruit of Rubus coreanus (RC), a perennial herb, has been cultivated for a long time as a popular vegetable. The anti-allergy mechanism of RC is unknown. The purpose of this study is to investigate the inhibitory effect of RC on compound 48/80- or anti-DNP IgE-induced mast cell activation. Methods: For this, influences of RC on the compound 48/80-induced degranulation, histamine release, calcium influx and the change of the intracellular cAMP (cyclic adenosine-3',5' monophosphate) levels of rat peritoneal mast cells (RPMC) and on the anti-DNP IgE-induced histamine release of RPMC were observed. Results: The pretreatment of RC inhibited compound 48/80-induced degranulation, histamine release and intracelluar calcium uptake of RPMC. The anti-DNP IgE-induced histamine release of RPMC was significantly inhibited by pretreatment of RC. The RC increased the level of intracellular cAMP of RPMC, and the pretreatment of RC inhibited compound 48/80-induced decrement of intracellular cAMP of RPMC. Conclusion: These results suggest that RC contains some substances with an activity to inhibit the compound 48/80- or anti-DNP IgE-induced mast cell activitation. The inhibitory effects of RC are likely due to the stabilization of mast cells by blocking the calcium uptake and enhancing the level of intracellular cAMP.

• 전기전자학회논문지
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• 제19권3호
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• pp.357-365
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• 2015

최근 항공기, 자동차와 같은 시스템들은 크기, 무게, 전력 등의 문제로 기존 연합형(Federated) 구조에서 모듈형(Modular) 구조로 개발되는 추세이며, 단일 하드웨어에 파티션 개념을 적용하여 다수의 논리적 노드들을 운용할 수 있는 파티션 운영체제도 등장하고 있다. 분산 복구 블록은 실시간 시스템에 적용 가능한 소프트웨어 결함 허용 기법으로 다수의 물리적 노드들을 동기화 시켜 동작시킴으로써 실시간 절체가 가능하도록 하는 설계 기법이다. 분산 복구 블록은 노드들 간의 실시간 동기화를 필요로 하기 때문에 단일 코어 기반의 파티션 구조에는 적합하지 않으며, 적용을 위해서는 멀티코어를 기반으로 하고 또한 AMP(Asymmetric Multi-Processing) 방식을 이용한 파티션 구조에 적용되어야 한다. 본 논문에서는 멀티코어 기반 supervised-AMP 가상화 방식의 파티션 운영체제를 이용한 분산 복구 블록 설계 기법을 제안한다. 또한 제안된 설계 기법의 유용성을 보이기 위하여 항공기용 비행제어시스템 시뮬레이션을 이용한 사례 연구를 보인다.

• 대한한방내과학회지
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• 제21권1호
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• pp.156-161
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• 2000

The unripe fruit of Poncirus trifoliata Raf has been used for the treatment of allergic disease. Recently it was reported that the fruit inhibits passive cutaneous anaphylaxis and histamine release at mast cell. Type I immediate hypersensitivity of anaphylactic type is caused by released mediate chemical at mast cell. Histamine is also known as one of potent mediate chemical. Also release of mediate chemical is affected by specific stimulation of IgE combined with mast cell. Activation of mast cell is known to be stimulated by compound 48/80 and inhibited by increase of cAMP. In this experiment, the effect of water extract of Poncirus trifoliata Raf fruit (PT) on a histamine release, cAMP concentration and IgE production was measured. Compound 48/80 was administrated to the mouse peritoneal cell which was pretreated with PT. PT dosedependently inhibited histamine release at peritoneal mast cell and the serum level of histamine induced by compound 48/80. PT also instantly increased cAMP level of peritoneal mast cell right after it was added and the level gradually decreased. Production of IgE induced by antigens at mouse peritoneal cell was inhibited by PT. The IgE synthesis is induced by IL-4 and it is known that lipopolysaccharide(LPS) plus IL-4 cause an increase in IgE secretion by murine B cells. The effects of PT inhibited the production of IgE activated by LPS plus IL-4 at human U266B1 cells. These results indicate that PT has antiallergic activity by Inhibition of IgE production from B cells and histamine release by increase of cAMP.

• The Korean Journal of Physiology and Pharmacology
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• 제22권4호
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• pp.391-398
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• 2018

The aim of this study was to evaluate the in vitro anti-inflammatory and utero-relaxant effect of ${\alpha}$-bisabolol on the pregnant human myometrium. Samples from the pregnant human myometrium were used in functional tests to evaluate the inhibitory effect of ${\alpha}$-bisabolol (560, 860, 1,200 and $1,860{\mu}M$) on spontaneous myometrial contractions. The intracellular cyclic adenosine monophosphate (cAMP) levels generated in response to ${\alpha}$-bisabolol in human myometrial homogenates were measured by ELISA. The anti-inflammatory effect of ${\alpha}$-bisabolol was determined through the measurement of two pro-inflammatory cytokines, tumor necrosis factor-${\alpha}$ ($TNF{\alpha}$) and interleukin $(IL)-1{\beta}$, and the anti-inflammatory cytokine IL-10, in pregnant human myometrial explants stimulated with lipopolysaccharide (LPS). Forskolin was used as a positive control to evaluate the cAMP and cytokine levels. ${\alpha}$-Bisabolol was found to induce a significant inhibition of spontaneous myometrial contractions at the highest concentration level (p<0.05). ${\alpha}$-Bisabolol caused a concentration-dependent decrease in myometrial cAMP levels (p<0.05) and a concentration-dependent decrease in LPS-induced $TNF{\alpha}$ and $IL-1{\beta}$ production, while IL-10 production did not increase significantly (p>0.05). The anti-inflammatory and utero-relaxant effects induced by ${\alpha}$-bisabolol were not associated with an increase in cAMP levels in pregnant human myometrial samples. These properties place ${\alpha}$-bisabolol as a potentially safe and effective adjuvant agent in cases of preterm birth, an area of pharmacological treatment that requires urgent improvement.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3110-3114
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• 2009

회전자 온도 변화는 유도 전동기 제어기 설계에 있어서 중요한 쟁점이다. 문헌에서, 수많은 연구들이 회전자 온도 변화를 고려하지 않는다면, 그에 기인한 심각한 성능 저하를 언급해왔다. 하지만, 이러한 연구들은 추종 성능 관점에서 주로 Field-oriented 제어기에 초점을 두고 있으며, 단위 전류당 최대 토크 제어기와 같이 최적 제어의 경우에서의 성능에 미치는 회전자 온도 변화의 영향에 대한 연구는 전무하다. 본 연구는 회전자 온도가 시간에 따라 변화함에 따라, 단위 전류당 최대 토크 제어기의 성능에 어떻게 영향을 미치는지를 조사한다. 이를 위해, 두 가지 방법으로 단위 전류당 최대 토크 제어기의 목적이 성취되는 지를 점검한다. 즉, 요구되는 토크를 발생시키면서 동시에 최소 가능한 고정자 전류를 필요로 하는 것이다. 실험실 실험결과는 추종 성능과 단위 전류당 최대 토크 조건이 회전자 온도가 변화함에 따라 심각한 영향을 받으며, 결과적으로 단위 전류당 최대 토크 제어기의 성능저하를 초래함을 보여준다.

• 대한한의학회지
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• 제18권1호
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• pp.316-325
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• 1997

The dried unripe fruit of Poncirus trifoliata L. is widely used to treat urticaria, itch and indigestion in folk medicine. And recently it was reported the component of the fruit was found to exhibit an inhibitory effect on histamine release from mast cells. So to evaluate the effect of aqueous extract of Poncirus trifoliata L.(PTFE) on compound 48/80-induced histamine release, the study was carried out in rat peritoneal mast cell. PTFE $(10^{-3}{\sim}1mg/ml)$ inhibits the histamine release induced by compound 48/80 $(5{\mu}g/ml)$ in rat peritoneal mast cells. To clarify the mechanism of these inhibition, we investigated the effect of PTFE on cAMP and intracellular calcium content. The increase in cAMP content, when PTFE was added, was transient. At concentration of 1mg/ml, the cAMP content of mast cells was significantly increased at a rate of 53 times of basal cells at 10sec. PTFE inhibits histamine release by augmenting the cAMP content in mast cells. Moreover, PTFE inhibits intracellular calcium release induced by compound 48/80. This result suggests that PTFE may be useful for the prevention and treatment of allergy-related disease.