• Molecules and Cells
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• v.26 no.5
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• pp.481-485
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• 2008

As an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), D609 has been widely used to explain the role of PC-PLC in various signal transduction pathways. This study shows that D609 inhibits group IV cytosolic phospholipase $A_2$ ($cPLA_2$), but neither secretory $PLA_2$ nor a $Ca^{2+}$-dependent $PLA_2$. Dixon plot analysis shows a mixed pattern of noncompetitive and uncompetitive inhibition with $K_i=86.25{\mu}M$ for the $cPLA_2$ purified from bovine spleen. D609 also time- and dose-dependently reduces the release of arachidonic acid from a $Ca^{2+}$- ionophore A23187-stimulated MDCK cells. In the AA release experiment, $IC_{50}$ of D609 was ${\sim375}{\mu}M$, suggesting that this reagent may not enter the cells easily. The present study indicates that the inhibitory effects of D609 on various cellular responses may be partially attributable to the inhibition of $cPLA_2$.

• Journal of Life Science
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• v.9 no.2
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• pp.52-56
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• 1999

The Raf, a cytoplasmic serine/thereonine protein kinase, acts as an important mediator of signals involving cell proliferation, differentiation and development. Multiple regulatory elements should participate in the expression of D-raf, Drosophila homolog of human c-raf-1. In order to search regulatory factors involved in the D-raf promoter activation, we accomplished the yeast one-hybrid screening using D-raf promoter region from bp-330 to -309 with respect to the transcription initiation site as bait. After screening, sixteen independent positive clones of ${\beta}$-galactosidase activties were identified and sequenced. Two clones having 94-98% identity with daughterless and one clone having 93% identity with escargot by Blast search among these clones were screened.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.609-612
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• 2020

보급형 FFF 3D프린터에서 발생되는 문제점인 화재의 위험, 사용자의 불편성, 장시간의 프린팅 시간으로 인한 문제등을 해결하기 위하여 보급형 FFF 방식의 3D프린터에 많이 사용되는 ATmega ARM 기반 칩셋의 보드를 분석하여 시리얼 통신을 이용한 원격 프로그램을 구성하여 보급형 FFF 3D프린터에서 발생되는 문제점을 해결하고자 하였다.

• The Bulletin of The Korean Astronomical Society
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• v.32 no.2
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• pp.74.2-74.2
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• 2007

• Animal cells and systems
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• v.2 no.1
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• pp.117-122
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• 1998

D-raf, a Drosophila homolog of the human c-raf-1, is known as a signal transducer in cell proliferation and differentiation. A previous study found that the D-raf gene expression is regulated by the DNA replication-related element (DRE)/DRE-binding factor (DREF) system. In this study, we found the sequences homologous to transcription factor C/EBP, MyoD, STAT and Myc recognition sites in the D-raf promoter. We have generated various base substitutional mutations in these recognition sites and subsequently examined their effects on D-raf promoter activity through transient CAT assays in Kc cells with reporter plasmids p5'-878DrafCAT carrying the mutations in these binding sites. Through gel mobility shift assay using nuclear extracts of Kc cells, we detected factors binding to these recognition sites. Our results show that transcription factor C/EBP, STAT and Myc binding sites in D-raf promoter region play a positive role in transcriptional regulation of the D-raf gene and the Myo D binding site plays a negative role.

• Journal of Life Science
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• v.10 no.1
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• pp.48-50
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• 2000

The cytogenetic pattern of autosome and sex chromiosome after Giemas staining were examined in the hybrids between two sibling species, Drosophila melanogaster and D. simulans. The analysis of karyotype in the hybrid female between D. melanogaster females and D. simulans males could be easily distinguished the characteriation of eight chromosomes from bothe species, especially with regard to X chromosomes. The lagging duplication of Y chromosome was investigated in the interspecific hybrid males from the cross between female of Drosophila melanogaster(OR) and males of D. simulasn (K18). On the other hand, the X chromatids of D. simulans were loosely separated in the early stage of anaphase.

• The Korean Journal of Ecology
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• v.19 no.2
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• pp.151-163
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• 1996

To investigate the early symptoms of light-chilling, alterations of chlorophyll fluorescence transients were monitored in cucumber (Cucumis sativus L. cv. Ilmichungjang) leaves. During 24 h chilling, decreases in (Fv)m/Fm, qE and qQ, and an increase in Fo were observed. The chilling effects were not recovered at room temperature, and a significant increase in Fo was observed during the recovery period. After 6 h chilling, ‘dip’(D) level of the transients became obscure, and the negative slope after ‘peak’(P) disappeared. The first derivative (dFv/dt) of the fast fluorescence rise curve was used to obtain more accurate information about the changes in the transients. The maximal rate of the fluorescence increase in the D-p rise curve (Fr) has been the most frequently used chilling stress indicator. However, a correct value of Fr could not be measured when the D level became obscure. This problem was overcome by introducing a new indicator, HFr (dFv/dt at Fv = 1/2 (Fv)m), and HFr gave very similar values to Fr. To monitor the changes in curvature around D level, another new parameter, ${\Delta}S$(D-Fr), was also introduced. These three parameters decreased very sensitively during light-chilling. In addition, increases in these parameters were observed during the first 2 h chilling, but this increase in Fr was also observed in pea leaf discs dark-chilled for 15 min, suggesting that this very early change is a common response to chilling in both pea and cucumber leaves. Quenching coefficients were also very sensitive to chilling, especially qE. Discussion on the usage of these parameters as chilling stress indicators is given in the text.

• Journal of applied mathematics & informatics
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• v.31 no.5_6
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• pp.609-621
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• 2013

At present, research on providing new methods to solve nonlinear integral equations for minimizing the error in the numerical calculations is in progress. In this paper, necessary conditions for existence and uniqueness of solution for nonlinear 2D Fredholm integral equations are given. Then, two different numerical solutions are presented for this kind of equations using 2D shifted Legendre polynomials. Moreover, some results concerning the error analysis of the best approximation are obtained. Finally, illustrative examples are included to demonstrate the validity and applicability of the new techniques.

• Communications of the Korean Mathematical Society
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• v.22 no.4
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• pp.609-621
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• 2007

Comparison of high Mach number jets using positive schemes and Weighted ENO methods is considered in this paper. The positive scheme introduced by [11, 14] and Weighted ENO [9, 10] have allowed us to simulate very high Mach numbers more than Mach 80. Simulations at high Mach numbers and with radiative cooling are essential for achieving detailed agreement with astrophysical images.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.46-47
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• 1995

Chitosan, an unbranched (1-4)-linked-2-amino-2-deoxy-$\beta$-D-glucan, is prepared by chemical N-deacetylation of chitin, which is the main structure element of the cuticles of crab, shrimp, and insects, and is found in the cell walls of bacteria. It has the same main chain in its molecule like that of natural heparin. Heparin, an anionic polysaccharide, is the best of anticoagulants that have been found so far. In this study, to improve the blood compatibility of chitosan, 2-(methacrylovloxy)-ethyl-2-(trimethylammonium)ethyl phosphate(MTP) with phospholipid polar groups was grafted on the chitosan membranes and the biochemical properties the MTP-grafted chitosan membranes were investigated.