• Molecules and Cells
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• 제37권12호
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• pp.899-906
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• 2014

Prostaglandin $E_2$ ($PGE_2$) promotes tumor-persistent inflammation, frequently resulting in cancer. Curcumin is a diphenolic turmeric that inhibits carcinogenesis and induces apoptosis. $PGE_2$ inhibits curcumin-induced apoptosis; however, the underlying inhibitory mechanisms in colon cancer cells remain unknown. The aim of the present study is to investigate the survival role of $PGE_2$ and whether addition of exogenous $PGE_2$ affects curcumininduced cell death. HCT-15 cells were treated with curcumin and $PGE_2$, and protein expression levels were investigated via Western blot. Reactive oxygen species (ROS) generation, lipid peroxidation, and intracellular glutathione (GSH) levels were confirmed using specific dyes. The nuclear factor-kappa B ($NF-{\kappa}B$) DNA-binding was measured by electrophoretic mobility shift assay (EMSA). $PGE_2$ inhibited curcumin-induced apoptosis by suppressing oxidative stress and degradation of PARP and lamin B. However, exposure of cells to the EP2 receptor antagonist, AH6809, and the PKA inhibitor, H89, before treatment with $PGE_2$ or curcumin abolished the protective effect of $PGE_2$ and enhanced curcumin-induced cell death. $PGE_2$ activates PKA, which is required for cAMP-mediated transcriptional activation of CREB. $PGE_2$ also activated the Ras/Raf/Erk pathway, and pretreatment with PD98059 abolished the protective effect of $PGE_2$. Furthermore, curcumin treatment greatly reduced phosphorylation of CREB, followed by a concomitant reduction of $NF-{\kappa}B$ (p50 and p65) subunit activation. $PGE_2$ markedly activated nuclear translocation of $NF-{\kappa}B$. EMSA confirmed the DNA-binding activities of $NF-{\kappa}B$ subunits. These results suggest that inhibition of curcumin-induced apoptosis by $PGE_2$ through activation of PKA, Ras, and $NF-{\kappa}B$ signaling pathways may provide a molecular basis for the reversal of curcumin-induced colon carcinoma cell death.

• Ecology and Resilient Infrastructure
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• 제5권1호
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• pp.25-34
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• 2018

본 연구에서는 만경강에서의 장기하상변동 모의를 실시하고 하상변동 이력을 분석하였다. 연구 대상 지역은 만경강의 중 하류 25 km 구간이다. 장기하상변동 모의를 위하여 HEC-RAS 프로그램을 사용하였으며 조도계수를 이용하여 모형을 보정하였다. 1986년부터 1993년까지의 기간과 1993년부터 2005년까지의 기간에 대하여 하상변동 모의를 수행하였으며, 실측된 하상고와의 비교분석을 실시하였다. MPM, Toffaleti, MPM-Toffaleti, Yang 공식의 네가지 유사이송 공식의 적용성을 평가하였다. 1986년부터 1993년까지의 기간에 대한 모의 결과, 네가지 공식 모두 실측치를 적절하게 모의하지 못하였다. 이는 모의구간 상류에서의 준설이 발생한 것으로 인한 결과이며 이후 기간에서 상류에서 퇴적이 활발이 진행되게 되는 결과를 초래하였다. 1993년 부터 2005년까지의 장기하상변동 모의는 MPM-Toffaleti의 공식이 모의를 적절히 수행해 냄을 확인하였다.

• 한국수자원학회논문집
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• 제44권1호
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• pp.9-22
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• 2011

본 연구에서는 에너지 방정식에 기초하여 정수 식생이 존재하는 자연하도에 적용 가능한 1차원 수치모형을 제시하였다. 수위계산을 위한 마찰경사는 Darcy-Weisbach의 마찰식에 의해 계산되었다. 각 단면의 전체 Darcy-Weisbach 마찰계수는 하상조도높이, 식생, 식생구역과 비식생구역 사이의 전단저항, 그리고 홍수터와 주수로의 경계면 전단저항을 고려하여 산정하였다. 경계면 마찰계수는 Mertens방법과 Nuding방법에 의해 계산되었다. 제시된 모형을 가상하도에 적용하고 HEC-RAS모형 모의결과와 비교, 검증하였고, 식생밀도 등에 대하여 마찰계수의 민감도 분석을 실시하였다. 모형의 적용성검토를 위하여 독일 Enz강 일부구간을 대상으로 수치모의를 실시하고 실측수위와 비교하였다. 식생이 존재하는 Enz강의 실측수위와 계산수위를 비교한 결과 식생의 영향을 거의 받지 않고 주수로에 흐름이 형성되는 저유량의 경우와 식생의 영향을 지배적으로 받는 고유량 흐름 모두에서 합리적인 수위를 예측하여 제시된 모형의 적용 가능성을 확인하였다.

• 한국습지학회지
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• 제15권1호
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• pp.91-103
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• 2013

본 연구에서는 자연친화적인 호안 블록의 현장 적용시 충분한 기술적인 검증과 구조적, 수리학적 안정성 검토 등이 제대로 이루어지지 않고 있는 문제점을 개선하기 위해 생태적 기능을 확보할 수 있는 식생강화를 위한 다공성 소일 블록에 대하여 수리적 거동 변화에 따른 수리학적 안정성을 검토하였다. 대상구간을 선정하여 수치해석 및 수리모형실험을 실시하였으며 수치해석을 위해 1차원 수치해석모형인 HEC-RAS와 2차원 수치해석모형인 RMA-2를 이용하여 1, 2차원 수치해석을 실시하였고, Froude 상사법칙을 적용하여 식생 유, 무에 따른 축척된 수리모형실험을 실시하였다. 수리모형실험의 경우 실험결과에 대한 타당성을 위해 축척된 수리모형실험의 유속 및 소류력 결과를 원형으로 환산하여 1, 2차원 수치해석결과와 동일한 조건하에 비교 검토하였고 그 결과 비교적 일치된 결과가 나타난 것으로 확인되었으며 이에 따른 원형으로 환산된 소류력 결과를 기존 연구결과인 호안의 허용소류력과 비교함으로써 블록의 수리학적 안정성을 제시하였다.

• 대한본초학회지
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• 제25권4호
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• pp.121-128
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• 2010

Objectives : This study purposed to research the inhibitory effect of Berberidis Ramulus on the liver cancer. Methods : A total extract of Berberidis Ramulus decoction were prepared. Through the measurement of the cell proliferation, apoptosis, morphology and cytokine level from the extracts, the influence on HepG2 cell were compared. Results : Berberidis Ramulus extract significantly inhibited the proliferation, increased the apoptosis, decreased the TGF-${\beta}$ gene expression and the K-RAS gene expression, significantly increased the level of TNF-${\alpha}$ secretion and increased the rates of IFN-${\gamma}$ secretory cells. Conclusion : It is suggested that Berberidis Ramulus extract turned out to have anti-cancer effects on HepG2 cell.

• 대한산업공학회지
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• 제34권2호
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• pp.140-150
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• 2008

Point Coordination Function (PCF) of the IEEE 802.11 protocol providing a centrally-controlled polling-based multiple access to a wireless channel is very efficient in high load conditions. However, its performance degrades with increasing the number of terminals and decreasing the load, because of wastes related to unsuccessful polling attempts. To solve the problem, we propose and study analytically the generic dynamic polling policy using backoff concept. For this aim, we develop Markov models describing the network queues changes, what allows us to estimate such performance measures as the average MAC service time and the average MAC sojourn time, to show the dynamic polling efficiency and to tune optimally the backoff rule.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.313.3-314
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• 2002

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in response to a variety of cytokines and other proinflammatory stimuli. It has been known that aberrant up-regulation of COX-2 is associated with resistance to apoptosis. Contrary to the above notion. treatment of MCF10A-ras cells with the anti-tumor agent ET -18-O-$CH_3$ caused increased expression of COX-2 and its mRNA transcript. while inducing apoptosis as revealed by proteolytic cleavage of poly(ADP-ribose)polymerase. caspase-3 activation, and positive TUNEL staining. (omitted)

• IMMUNE NETWORK
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• 제9권2호
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• pp.35-40
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• 2009

Although Rap GTPases of the Ras family remained enigmatic for years, extensive studies in this decade have revealed diverse functions of Rap signaling in the control of cell proliferation, differentiation, survival, adhesion, and movement. With the use of gene-engineered mice, we have uncovered essential roles of endogenous Rap signaling in normal lymphocyte development of both T- and B-lineage cells. Deregulation of Rap signaling, on the other hand, results in the development of characteristic leukemia in manners highly dependent on the contexts of cell lineages. These results highlight crucial roles of Rap signaling in the physiology and pathology of lymphocyte development.

• 한국환경성돌연변이발암원학회지
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• 제22권1호
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• pp.54-59
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• 2002

We have used cDNA microarray hybridization to identify gene regulated in response to gamma-irradiation in U-937 cell. The cDNA-chip was composed entirely of 1,000 human cancer related gene including apoptosis and angiogenesis etc. In gamma-irradiated U-937 cell, highly charged protein, ribosomal protein L32, four and a half LIM domains 3, lipocalin 2 (oncogene 24p3) and interleukin 15, ataxia telangiectasia mutated (includes complementation groups A, C and D) genes showed increased level of its transcription, and cell division cycle 25A, dihydrofolate reductase, topoisomerase (DNA) II beta(180kD), kinase suppressor of ras and strarigin genes showed reduced level of its transcription compared to untreated U-937 cell. The significant change of level of transcription was not found in well-known ionizing radiation(IR)-responsive gene, such as transcription factor TP53 and p53 related gene, except ataxia telangiectasia mutated gene.

• 약학회지
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• 제41권6호
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• pp.765-772
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• 1997

Conformational analyses on thromboxane $A_2$ (Tx$A_2$) and thromboxane $A_2$ receptor antagonists (TxRA) were carried out by molecular mechanics method. Based on the assumption that active conformer is the nonintrahydrogen bonding and more stable former of Tx$A_2$ and TxRA, the molecular structural requirements for potent TxA2 receptor antagonists are like below: 1) The distance is 5.0-5.6${\AA}$ between C atom of carboxyl group and S atom of sulfonyl group or C atom which is bonded to hydroxyl group in the active conformers. 2) The putative active conformers of Tx$A_2$and TxRAs are hairpin-like forms.