• Development and Reproduction
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• v.4 no.2
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• pp.161-173
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• 2000

The aim of this study was to assess the effect of the frequency of the L$N_2$ infusion on the ultrastructure, metabolism and development of the embryo after freezing and thawing by computerized cell freezer. Two-cell embryos of ICR mouse were randomly allocated into fresh (control), high-frequency freezing (group 1) and low-frequency freezing (group 2). For fresh and frozen-thawed intact 2-cell embryos, total ceil number in the blastocyst was counted by fluorescent microscope after Hoechst 33258 staining. Relative amount of $H_2O$$_2$ was measured by DCHFDA. Intracellular location and membrane potential of the mitochondria were evaluated by staining with rhodamine 123 and JC-1. The structure of actin filament was also evaluated by confocal microscope. DNA fragmentation was assessed by TUNEL method after development into blastocyst. The survival rate of intact embryo was higher in group 1 than group 2 (50.7％ vs. 34.6％ respectively, p<0.05). The blastocyst developmental rate was significantly low in group 2 (86.7％, 76.7％ vs. 44.0％ for control, group 1 and group 2 respectively, p<0.05). Total cell number in the blastocyst was also significantly lower in group 2 than control (79.5$\pm$12.9, 71.6$\pm$8.0, and 62.5$\pm$4.7 for control, group 1 and group 2 respectively, p<0.05). The relative amount of $H_2O$$_2$ was higher in group 2 than other groups (15.3$\pm$3.0, 16.6$\pm$1.6 vs. 23.4$\pm$1.8, p<0.05). After JC-1 staining, relative intensity of mitochondria with high membrane potential was significantly lower in group 2 than control and group 1 (17.2$\pm$3.8, 17.4$\pm$1.3 vs. 13.2$\pm$2.0, p<0.05). In group 2, partial deletion and aggregation of the actin filament was found. DNA fragmentation rate was also hieher for group 2 versus other groups (30.8％, 36.0％ vs. 65.6％, p<0.05). The frequency of the L$N_2$ infusion is an important factor for the development of frozen-thawed mouse embryo. High-frequency infusion may prevent damages of cytoskeleton and mitochondria in the embryo probably by preventing the temperature fluctuation during dehydration phase. We speculate that the application of high-frequency infusion method in human embryo may be promising.

• Polymer(Korea)
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• v.32 no.4
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• pp.353-358
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• 2008

Maleated ethylene-propylene-diene terpolymer (MEPDM) was prepared from solution polymerization of EPDM and maleic anhydride. MEPDM-grafted-poly (dimethylsiloxane) (PDMS) copolymer (MEPDM-g-PDMS) was prepared from copolymerization of MEPDM with $\alpha$,$\omega$-hydroxyl group terminated PDMS. The MEPDM-g-PDMS was compounded with HDPE and 4-ethoxybenzoic acid modified MWCNT at $180^{\circ}C$ and positive temperature coefficient (PCT) behavior of the MWCNT composite was investigated. Surface modification of MWCNT enabled it to be more uniformly dispersed in polymer matrix and decreased aggregation of particles. Electrical resistivity of the composite was abruptly increased at melting temperature and PTC intensity of 2.3 was obtained at 15% loading of surface modified CNT.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.29-34
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• 2001

The mutant enzymes of N-carbamyl-D-amino aicd amidohydrolase (N-carbamylase) from Agrobacterium radiobacter NRRL B11291, showing a negligible activity, were selected from the library generated by random mutagenesis. From the sequence analysis, these mutants were found to contain the amino acids substitutions at Cys172, Glu47, and Glu146. Previously, Cys172 was reported to be necessary for the enzyme catalysis. The chemical modification of the N-carbamylase by carboxyl group specific chemical reagent, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide(EDC), resulted in a loss of activity. The replacement of glutamic acids with glutamines by site-directed mutagenesis led to aggregation of the enzymes. Mutant enzymes fused with maltose binding protein (MBP) were expressed in soluble form, but were inactive. These results indicate that two glutamic acid residues play an important role in structure and function of the N-carbamylase. Multiple sequence alignment of the related enzymes revealed that Glu47 and Glu146 are rigidly conserved, which suggests that tese residues are crucial for the structure and function of the functionally related C-N hydrolases.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.24 no.4
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• pp.23-51
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• 2013

The purpose of the study is to examine the potentialities and limits of Business Reference Model (BRM) as records classification schemes in Korean central state institutions. The analysis is based on the data collected through focus group interviews of three times, in which six records professionals from central government agencies participate. This paper begins with inquiring the framework of records classification based BRM, required by Public Records Management Act. It explores the types of benefit of BRM application to government records classification. Based on the collected data from the interviews, it investigates how records are aggregated, and how transaction level (Danwi-Gwaje) of BRM is applied in the course of records aggregation.

• Journal of KIISE:Software and Applications
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• v.26 no.5
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• pp.604-612
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• 1999

데이터웨어하우스는 데이터분석을 위한 특수 목적의 데이터베이스로, 주로 데이터분석을 위한 질의(이하 OLAP 질의)가 던져진다. 그런데 OLAP질의는 수백만개의 레코드를 가지 테이블에 대해 하나 이상의 aggregation 함수와 group-by 연산자가 포함되므로, 질의 처리 시간은 수 분에서 수 시간이 걸린다. 이를 개선하기위하여 데이터 큐브를 구현함에 있어서의 문제는 디스크 공간이 한정되어 있기 때문에 평균 질의 처리 시간이 훨씬 짧아진다하더라도 모든 셀들을 실체화할수 없다. 따라서 한정된 디스크 공간을 최대한 활용하면서 가능한 빠른 평균 질의 처리 시간을 얻을 수 있도록 데이터 큐브의 일부만을 실체화 시켜야한다. 본 논문의 주제와 관련된 연구로는 Harinarayan[4] 이 제안한 greedy 알고리즘이 있다. 이 알고리즘은 1) 데이터 큐브를 격자구조로 표현한후, 2) 격자의 위에서부터 아래로 차례로 뷰들을 방문하면서 방문한 뷰가 실체화되 경우 데이터 큐브에 주는 이익을 계산한다. 3) 그 중 가장 이익이 큰 것을 선택한다. 3) 그중 가장 이익이 큰 것을 선택한다. 2)와 3)의 과정은 k개의 뷰를 선택할 경우, k번 반복된다. 이 알고리즘의 운영 시간은 데이터 큐브를 구성하는 뷰의 개수가 n개이고 그 중에서 k개를 실체화할 경우에 O(kn2)이다. 본 논문에서는 운영 시간을 향상시킨 수정된 greedy 알고리즘을 제안한다. 알고리즘 내부에서 실체화할 뷰를 선택할 때 격자를 단순화시킨 트리를 사용함으로써, 알고리즘 운영시간을 O(kn2)에서 O(kn)으로 향상시켰다.

• The Journal of Korean Medicine
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• v.27 no.4
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• pp.162-173
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• 2006

The water-extracts of Scutellaria barbata Don (SBDE) were isolated from Chinese medicinal plant sources. The extracts showed strong growth-inhibitory activity and cancer chemopreventive activity on the growth and DNA incorporation of MG63 human osteosarcoma and K562 human leukemia cell lines. The growth of human cancer cells was inhibited in the presence of the extracts (20, 50 and 100 ${\mu}$g/ml), and the effects were concentration-dependent and incubation time-dependent up to 8 days. When 50 ${\mu}$g/ml of the extracts was added to the media of MG63 and K562, cell growth after 8 days or 6 days of incubation was retarded by 93.2 to 97.3% of the control group. Morphological changes of MG63 and K562 cell lines were observed. As the concentration of the extracts increased up to 50 ${\mu}$g/ml, degree of cell aggregation decreased. Moreover, the DNA incorporation of the cells which were labeled with [3H] thymidine was significantly reduced after 3 days of incubation at $37^{\circ}C$ with the extract. Therefore, it is suggested that the extract is highly effective on inhibition of cancer cell growth. The extract also inhibited gene expression of IGF-II in transcriptional level. Since IGF-II works as a mitogenic effector on MG63 and K562 cell lines, these results suggest that the growth inhibition is in part mediated through the inhibition of IGF-II gene expression.

• Environmental Analysis Health and Toxicology
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• v.24 no.3
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• pp.231-240
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• 2009

We explored collective behaviors of indicator species to elucidate the effect of the chemical stress. After the treatments of an insecticide, diazinon, at low concentrations (1.0 and 10.0 ${\mu}g/L$), spatial dispersion patterns of Daphnia magna were checked in a test chamber. The I-index was used to characterize the movement data before (0~1 h) and after (1~2 h) the treatments in laboratory conditions. The slopes of the frequency distribution of I-index in semi-log scale decreased significantly, and the test populations appeared to be more dispersed with a lower degree of aggregation after the treatments. The index was feasible in indicating decrease in the ability of the specimens to keep desirable distances with neighbor individuals under chemical stress and showed a possibility of monitoring presence of toxic chemicals in environment through group behavior measurement.

• Journal of the Korean Applied Science and Technology
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• v.19 no.1
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• pp.43-48
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• 2002

We carried out this subject to observe photoisomerization using 1,2-dioleoyl-sn- glycero-3-phosphocholine(DOPC) mixed with fatty acid containing azobenzene group which has reversible to cis-trans by light irradiation. Spreading solutions for the LB films were prepared in chloroform($5.0{\times}10^{-5}$mol/L).We investigated the photoisomerization and property of the organic ultra thin film of fatty acid containing azobenzene was prepared on the hydrophilic ITO(idium tin oxide) glass plate by LB method. As a result, the absorption spectra of 8A5H and DOPC of mixture LB films was induced to photoisomerization by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipid into the monolayers, and the molecular high aggregation in pure azobenzene monolayers is also weakened by the introduction of phospholipid. We found that it was reversibly induced to cis-trans photoisomerization in several solvents and mixture LB films.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3045-3051
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• 1997

Generally, multi-criteria decisions are made by group of people because of their complexity. In the existing fuzzy aggregation method, the operators using minimum, maximum and average are used to aggregate the viewpoints of many staffs. These methods have problems in that they do not reflect the decision situation in the decision process. In order to solve these problems we propose a new fuzzy multi-criteria decision support systems model that aids the decision maker to aggregate the viewpoints of many staffs according to the decision situation. Moreover, we design the algorithms which can be used in the fuzzy multi-criteria decision support systems and develop its prototying system.

• Korean Journal of Pharmacognosy
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• v.26 no.4
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• pp.385-389
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• 1995

MeOH extract of Gastrodia elata was fractionated to five solvent fractions, hexane fr (fr I), 90% MeOH fr (fr II), EtOAc fr (fr III), BuOH fr (fr IV) and $H_2O$ fr (fr V). Among the five fractions, fr II, III and IV showed platelet anti-aggregating effects against ADP or collagen induced rat platelet aggregation in vitro. Fr II , III and IV were also tested in vivo, in the mouse and rat models of thrombosis. Oral administration of fr II, III or IV enhanced the recovery from the thrombotic shock in the mouse model of thrombosis to 32-40% from 17% of recovery with the control group of mice. Treatment with fr II, III or IV also attenuated the sudden reduction in the blood platelet count following intravenous collagen injection to rat. The above results were indicative of the presence of anti-platelet and anti-thrombotic components in this plant.