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        검색결과 1,884

        1781.
        2014.09 서비스 종료(열람 제한)
        Development of the central nervous system (CNS) occurs normally in mammalian fetus despite lower temperature in the brain region than in the heart. To investigate the effects of temperature niche on the neural differentiation of stem cells in vitro, P19 embryonic carcinoma (EC) stem cells and N2a neuroblastoma stem cells were induced to undergo neural differentiation by retinoic acid and LiCl, respectively. The cells were analyzed for the expression of neural marker genes during 12 days differentiation. Although there were Map2 and NCAM expressions in both groups, no clear difference was found. Similarly, expression patterns of Tuj1 and NF-M were not different in both groups, showing more intensive staining patterns at day 12 than those at days 4 and 8, respectively. However, more cells expressed GFAP markedly at day 12 in 37℃ group. There was little expression of the above markers in N2a cells during differentiation except for Ngn2 and Tuj1. It was found that Ngn2 was expressed more intensely at days 6 and 9 in 33℃ group. Tuj1 expression showed a similar pattern to those of P19 EC cells. RT-PCR analysis also showed that the expressed transcripts did not quite different in both groups, although they were different among the days of differentiation. Thus, it appears that neural differentiation occurs normally with a slight delay and probably less cell death in the cells at 33℃ than that at 37℃.
        1782.
        2014.09 서비스 종료(열람 제한)
        Chemoresistance is one of the main problems to treat different kinds of cancers or cancer cells. Therefore, it is necessary to find out the strategies to make the cancer cells sensitive to chemotherapy along with optimal dosage of drugs. We examined sensitivity of MCF7 cells through pretreating with an epigenetic modulator, azacytidine (AzaC) to doxorubicin (Dox). The cells were treated with 5 and 10 mM of AzaC for a week, subsequently with 50, 100 and 500 nM of doxorubicin for 24 and 48h. It was found that pretreatment of AzaC significantly enhance the sensitivity of MCF7 cells to Dox, inducing cell death. After 24h 15% cells underwent apoptosis in 500 nM dox treatment group while 23.4% cells death occurred in AzaC pre treatment group. After 48h MCF7 cells treated with Dox showed 19.0% cell death while AzaC sensitized cells showed 50.0% cells death when exposed to 500 nM of Dox for 48h. Western blot analysis showed the upregulations in the expression of bax, caspase-3, caspase-9 and p53 in AzaC-sensitized MCF7 cells treated with Dox as compared to those treated with only Dox. There was no clear indication for pro-apoptosis genes in the cells treated with individual drugs. These results showed that pretreatment with the epigenetic modulator significantly increased the sensitivity of MCF7 cells to Dox. Therefore it is concluded that demethylation event might enhance the activity of DNA intercalating agents to induce DNA damage in breast cancer cells.
        1783.
        2014.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Next Generation Small Satellite-1 (NEXTSat-1) is scheduled to launch in 2017 and Instruments for the Study of Space Storm (ISSS) is planned to be onboard the NEXTSat-1. High Energy Particle Detector (HEPD) is one of the equipment comprising ISSS and the main objective of HEPD is to measure the high energy particles streaming into the Earth radiation belt during the event of a space storm, especially, electrons and protons, to obtain the flux information of those particles. For the design of HEPD, the Geometrical Factor was calculated to be 0.05 to be consistent with the targets of measurement and the structure of telescope with field of view of 33.4° was designed using this factor. In order to decide the thickness of the detector sensor and the classification of the detection channels, a simulation was performed using GEANT4. Based on the simulation results, two silicon detectors with 1 mm thickness were selected and the aluminum foil of 0.05 mm is placed right in front of the silicon detectors to shield low energy particles. The detection channels are divided into an electron channel and two proton channels based on the measured LET of the particle. If the measured LET is less than 0.8 MeV, the particle belongs to the electron channel, otherwise it belongs to proton channels. HEPD is installed in the direction of 0°,45°,90° against the along-track of a satellite to enable the efficient measurement of high energy particles. HEPD detects electrons with the energy of 0.1 MeV to several MeV and protons with the energy of more than a few MeV. Thus, the study on the dynamic mechanism of these particles in the Earth radiation belt will be performed.
        1784.
        2014.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The application of software engineering is not common in the development of astronomical observation system. While there were component-wise developments in the past, large-scale comprehensive system developments are more common in these days. In this study, current methodologies of development are reviewed to select a proper one for the development of astronomical observation system and the result of the application is presented. As the subject of this study, a project of operation software development for an astronomical observation system which runs on the ground is selected. And the output management technique based on Component Based Development which is one of the relatively recent methodologies has been applied. Since the nature of the system requires lots of arithmetic algorithms and it has great impact on the overall performance of the entire system, a prototype model is developed to verify major functions and performance. Consequently, it was possible to verify the compliance with the product requirements through the requirement tracing table and also it was possible to keep to the schedule. Besides, it was suggested that a few improvements could be possible based on the experience of the application of conventional output management technique. This study is the first application of the software development methodology in the domestic astronomical observation system area. The process and results of this study would contribute to the investigation for a more appropriate methodology in the area of similar system development.
        1785.
        2014.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The first Korean satellite laser ranging (SLR) system, Daedeok SLR station (DAEK station) was developed by Korea Astronomy and Space Science Institute (KASI) in 2012, whose main objectives are space geodesy researches. In consequence, Korea became the 25th country that operates SLR system supplementing the international laser tracking network. The DAEK station is designed to be capable of 2 kHz laser ranging with precision of a few mm both in daytime and nighttime observation of satellites with laser retro-reflector array (LRA) up to the altitude of 25,000 km. In this study, characteristics and specifications of DAEK station are investigated and its data quality is evaluated and compared with International Laser Ranging Service (ILRS) stations in terms of single-shot ranging precision. The analysis results demonstrated that the DAEK station shows good ranging performance to a few mm precision. Currently, the DAEK station is under normal operations at KASI headquarters, however, it will be moved to Sejong city in 2014 to function as a fundamental station for space geodesy researches in combination with other space geodesy systems (GNSS, VLBI, DORIS, etc.).
        1786.
        2014.07 서비스 종료(열람 제한)
        Abiotic environmental stresses cause serious economic losses in agriculture. These stresses include temperature extremes, high salinity and drought. We identified several drought stress-related novel/function unknown coding transcripts (transcription factors and functional genes) and non-coding transcripts (small noncoding transcripts such as microRNA and long noncoding transcripts) using the next generation sequencing method from rice (Oryza sativa L.), and have constructed databases of drought stress-related coding and noncoding transcripts. We used novel gene prediction programs for the selections. The expression level of the each gene was analyzed by real-time PCR. The results ended up the selection of 29 transcription factors, 6 microRNAs and 10 long noncoding RNAs. Currently, we are further characterizing these transcripts. We expect that this study could provide functional information of the drought stress-regulated novel genes, and relationships among novel coding and noncoding transcripts.
        1787.
        2014.07 서비스 종료(열람 제한)
        Fresh market tomato cultivars are divided largely based on fruit color appearance (red or pink), which is attributed by the trait of peel. It had been reported that mutation of the Slmyb12 gene suppresses synthesis of yellow-colored flavonoid (naringenin chalcone) in peel and causes pinkish tomato fruit. Whereas wild-type tomato plants synthesizing naringenin chalcone produce yellow-colored peel, which resulting in the fruit appearance to be red. The present study was performed to investigate the association between the Slmyb12 and fruit color of domestic tomato inbreed lines. A SCAR marker was developed from an Indel mutation site (72bp insertion in exon3) of the Slmyb12, and tested on 22 and 18 red and pink-fruited inbred lines, respectively. Unexpectedly, the results showed that all inbred lines tested had wild-type Slmyb12. The full length sequences of the Slmyb12 were cloned from two inbred lines (FCR1 and FCP1), but the sequence alignment did not identify any nucleotide variations within this gene. Furthermore, scanning of SNPs between FCR1 and FCP1 using SolCAP Tomato SNP array) found no SNPs for Slmyb12. To delimit the genomic region of the gene conferring fruit color of domestic tomato lines, we are analyzing SNPs in the genes adjacent to the Slmyb12 using an F2 population derived from FCR1 x FCP1. So far, one SNP located at 1,750kbp downstream from the stop codon of Slmyb12 was mapped using 54 F2 plants and 83% of phenotype-marker association was revealed, demonstrating that the fruit color is controlled bySlmyb12 indeed, or other neighboring gene(s) involved in the pathway of naringenin chalcone synthesis. Further study with more SNPs will clear up this question.
        1788.
        2014.07 서비스 종료(열람 제한)
        Most of the melon(Cucumis melo L.) breeding lines in Korea show andromonoecious (male-perfect flowers) sex expression, which requires laborious hand emasculation to produce the F1 seeds. There is a high demand for developing monoecious (male-female flowers) elite germplasm. The present study was carried out to develop molecular markers for selecting monoecious plants based on the CmACS-7 gene [a locus with 1-aminocyclopropane-1-carboxylic acid synthase(ACS) activity] responsible for ethylene synthesis and sex determination in melon. The full length sequences of the CmACS-7 were cloned from a monoecious inbred ‘Mo23’ and an andromonoecious inbred ‘Am24’. Sequence alignment revealed a major SNP(C170T) in exon1 and 18bp indel in intron4 of the CmACS-7, and a CAPS (SNP-C170T) and SCAR (ID4-18) were developed from the SNP and indel, respectively. A total of 453 F2 plants derived from ‘Mo23’ x ‘Am24’ were determined for their sex expression and genotyped using the SCAR marker. A Mendelian ratio of 3(monoecy): 1(andromonoecy) was observed from the F2 population, and sex type of 449 plants (except for four plants that showed incomplete monoecy) cosegregated with the SCAR marker, demonstrating that CmACS-7 is a single dominant gene conferring monoecy of ‘Mo23’. Allele variation of the CmACS-7 was evaluated by genotyping 114 melon accessions with diverse geographical origins using the CAPS and SCAR. C170T-SNP in exon1 of the CmACS-7 was highly conserved in melon germplasm and perfectly matched with the phenotype, whereas the 18bp-indel mutation in intron4 existed in various forms. The results demonstrated that CAPS marker SNP-C170T can be useful for marker-assisted selection(MAS) of monoecious melon plants
        1789.
        2014.07 서비스 종료(열람 제한)
        As one of the most important crop, rice is not only a staple food of half world’s population but a wonderful model plant, which has been leading the evolution and functional genomics study. The next-generation sequencing technology are expediting rice genomic study, by providing a simple but powerful way. In this study, we re-sequenced a core collection of 137 rice accessions from all over the world along with 158 Korean breeding varieties. Finally, 6.3G uniquely mapped reads were obtained, and about 10 million SNPs and ~1.2 million InDels were identified with average sequencing depth of 7.5X. These will help us to maximize our germplasm utilization and assists all the deep research in population dynamics and functional studies. Here, we’d like to show the approaches applied to resequencing data mining and on-going activities.
        1790.
        2014.07 서비스 종료(열람 제한)
        This study was conducted to determine the optimal dose of gamma-ray for mutation breeding in sorghum (Sorghum bicolor M.). Gamma-rays irradiated to dry seeds with various doses (0 to 1000 Gy) at Korea Atomic Energy Research Institute. Lethal dosage (LD50) was approximately 256 Gy. Significant decreases in growth characteristics (plant height, tiller number and fresh weight) were observed by dose of increased over 300 Gy. Reduction doses (RD50) was approximately 363 Gy in plant height. We also conducted comet assay to observe nucleus DNA damage due to gamma irradiation. In comet assay, a clear difference was identified over 100 Gy treatments. With increasing doses of gamma-ray in the range of 100 to 400 Gy, the rate of head DNA was decreased significantly from 93.52% to 67.57%. The most of the Sorghum cells were severely damaged in the integrity of DNA by gamma-ray. These data provide valuable information when the optimal dose should be chosen for purpose of mutation breeding program of Sorghum.
        1791.
        2014.07 서비스 종료(열람 제한)
        Gliadins are the main class of wheat seed storage proteins. Since gliadins show a high level of polymorphism as well as genetically fixed, it can be used as a marker for the genetic identification. Gliadin subunit diversity information can be useful for wheat quality breeding programs. Tunisia is a country in the North Africa bordered with the Mediterranean Sea to the north and the east but with the Sahara desert to the south, which represent extremely different growth climate. Therefore, there may be a numerous variation in Tunisian common wheat and durum wheat. Total 48 lines of wheat consisted of 32 common wheat (16 Korean wheat and 16 Tunisian common wheat) and 16 Tunisian durum wheat were incorporated in this study. Gliadins were extracted with 70% ethanol and fractionated by acid polyacrylamide gel electrophoresis (A-PAGE) at 8% in aluminum lactate buffer (pH 3.1). The gel was stained with 0.25% Coomassie Brilliant Blue (CBB) R-250. The presence of each gliadin subunit band was scored and cluster analysis was carried out. The cluster showed that wheat varieties were classified into some groups and their genetic distance could be identified. The obtained information will be helpful to the future breeding program of tetraploid durum wheat as well as hexaploid common wheats. Acknowledgement: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2012K1A3A1A09028123) and carried out with the support of “Cooperative Research Program for Agriculture Science & Technology Development (Project title: Development of high yielding wheat with stress tolerance via molecular breeding strategies, Project No. PJ008031)”, Rural Development Administration, Republic of Korea.
        1792.
        2014.07 서비스 종료(열람 제한)
        Soil salinity limits crop productivity in many regions. This problem would be more serious as the global climate changes and worldwide water shortages would accelerate soil salinization. This study is fulfilled with aim on resolve crop cultivation in dry/saline land as an international joint research project with Tunisia. Total 48 lines of wheat cultivars including 32 common wheat (16 Korean wheat, 16 Tunisian common wheat) and 16 Tunisian durum wheat were incorporated in this study. Salt stress was applied for 2 weeks by submerging the pots into 500 mM NaCl at 3-leaf stage followed by re-watering for restoration in greenhouse. Numerous agronomic/growth parameters were scored for tolerence. SSR primers that have been known to be related to salt tolerance were applied to explain selected population. The correlation between PCR-based length polymorphism of selected lines and their resistance were evaluated. The obtained information will aid selection for salt tolerance hexa/tetraploid wheats. Acknowledgement: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2012K1A3A1A09028123) and carried out with the support of “Cooperative Research Program for Agriculture Science & Technology Development (Project title: Development of high yielding wheat with stress tolerance via molecular breeding strategies, Project No. PJ008031)”, Rural Development Administration, Republic of Korea.
        1793.
        2014.06 KCI 등재 서비스 종료(열람 제한)
        Purpose - The study aimed to evaluate the market opportunities and constraints confronting resource-poor pig farmers in South Africa. Research design, data, and methodology - Information was collected from 292 households in three municipalities through interviews with key informants. The data collected included socio- economic characteristics, major market channels, prices for different pig classes, average weight of the pigs on sale, number of pigs sold annually, and preferred meat quality attributes. Results - In Ngqushwa, 96% of respondents sold pigs as compared to Elundini (81%) and Ntabankulu (65%). Less resource- poor households and those with market-oriented production had large herdsizes (P < 0.05) when compared to more resource-poor farmers. The probability of selling pigs was high for the backyard production system and educated farmers. For all farmers, opportunities included high pork demand, good prices, employment creation, and a niche market for organically produced indigenous pork. Constraints include disease, feed shortages for large herds, distances to formal markets, lack of training, and drugs. Conclusions - Constraints outnumbered opportunities for the resource-poor pig farmers
        1797.
        2014.04 KCI 등재 서비스 종료(열람 제한)
        Purpose – This study attempts to examine Islamic banking practices in Iran based on new scientific methods. Design, methodology, and approach – The study used financial ratios demonstrating healthy or non-healthy banks to assess the financial health of banks listed on the Tehran Stock Exchange. The assessment of these ratios with a decision tree as a non-parametric method for modeling is recommended to present this model. Information about the financial health of banks could affect the decisions of different groups of banks’ financial report users including shareholders, auditors, stock exchanges, central banks, and so on. Results – The results of the study show that a decision tree is a strong approach for classifying Islamic banks in Iran. Conclusions – To date, several studies have been conducted in various countries on the topic of this study. Considering the importance of Islamic banking, this is one of the first studies in Iran the outcomes of the study may prove helpful to the Iranian economy.
        1798.
        2014.04 서비스 종료(열람 제한)
        System identification was performed on the swing span of a steel truss bridge using a wireless sensor network. The swing span can rotate 360° to allow river traffic to pass through the locks located under the bridge. The twenty-two wireless sensor nodes were installed on the span to measure synchronized tri-axial acceleration. Modal properties of the bridge according to its different positions were successfully obtained using frequency domain decomposition method, and compared with the ones from the FE model of the bridge.
        1799.
        2014.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        A package of space science instruments, dubbed the Instruments for the Study of Space Storms (ISSS), is proposed for the Next Generation Small Satellite-1 (NEXTSat-1), which is scheduled for launch in May 2016. This paper describes the instrument designs and science missions of the ISSS. The ISSS configuration in NEXTSat-1 is as follows: the space radiation monitoring instruments consist of medium energy particle detector (MEPD) and high energy particle detector (HEPD); the space plasma instruments consist of a Langmuir probe (LP), a retarding potential analyzer (RPA), and an ion drift meter (IDM). The space radiation monitoring instruments (MEPD and HEPD) measure electrons and protons in parallel and perpendicular directions to the geomagnetic field in the sub-auroral region, and they have a minimum time resolution of 50 msec for locating the region of the particle interactions with whistler mode waves and electromagnetic ion cyclotron (EMIC) waves. The MEPD measures electrons and protons with energies of tens of keV to ~400 keV, and the HEPD measures electrons with energies of ~100 keV to > ~1 MeV and protons with energies of ~10 MeV. The space plasma instruments (LP, RPA, and IDM) observe irregularities in the low altitude ionosphere, and the results will be compared with the scintillations of the GPS signals. In particular, the LP is designed to have a sampling rate of 50 Hz in order to detect these small-scale irregularities.
        1800.
        2014.02 서비스 종료(열람 제한)
        Urban stormwater runoff was considered to be more contaminated than the runoff from other land uses due to vehicle and human activities. Specifically, road runoff was commonly regarded as the primary pollutant (e.g. particulates and heavy metals) in the urban environment. Effectiveness of stormwater management strategies and treatment facilities in treating road runoff were highly based on the accuracy of the stormwater quantity and quality estimation. Although direct sampling of runoff during a storm event effectively quantifies the contaminant contributions in a specific area, it is expensive and time consuming. In order to efficiently design these treatment facilities based from the typical pollutant and hydrologic processes, the operation of modelling techniques were recommended. In this research, the physical characteristics of an existing tree box filter treating road runoff were adjusted using stormwater management model (SWMM) to determine the most suitable design configuration for better volume and pollutant reduction. The catchment area (CA), storage volume (SV) and surface area (SA) of the facility was increased or decreased by an increment of 25%. These changes were simulated by SWMM and would predict the influence of larger or smaller CA, SV or SA with respect to the facility performance. The hydrologic, hydraulic and water quality data used in the modelling were gathered from the 10 storm events monitored from July 2012 to July 2013. The total suspended solids were considered as the main target pollutants for this research however, the results will be correlated with the common heavy metal constituents present in the sampled runoff. Various design installations (e.g. series and parallel installation of tree box filter) were also modelled to accurately justify the obtained design configurations. Among the different configurations simulated, increasing the original values of the CA, SV and SA between 0.75% and twice the original value would result to better performance for the system. As for the installations being modelled, a centralized system would provide better volume and pollutant reduction than a divided system.