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        검색결과 79

        63.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We have mapped 17 deg2 region toward Galactic anticenter in 12CO J = 1 - 0 using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory (TRAO). The region mapped in this paper is the first target of the Galactic AntiCenter CO Survey Project (GACCOS) and was selected comparing with IRAS Sky Survey Atlas (ISSA) images at 100 μm. Molecular emission of the target area is found to be very extended and is well matching with the FIR emission boundary. There are several pieces of clouds, and as some of spectra show several peaks, there seem to be several clouds overlapped in some directions. The Velocity of Local Standard of Rest (VLSR) of the CO emission of the mapped region ranges from -20 to +10 km/s. It is also found that the two cloudlets located around I = 180° have VLSR = -20 km/s, which is very abnormal. The peak antenna temperature of 13 K arises near the H II Region S241.
        66.
        2013.07 서비스 종료(열람 제한)
        In U.S.A. maize breeding, exotic germplasm is considered as high-risk and usually introduced by backcrossing specific traits into elite lines. The U.S.A. maize germplasm base is narrow. Only a few open-pollinated varieties are well represented in current programs. Currently, the barrier in using of exotic germplasm in the U.S.A is less formidable than in the 1980s. The major reason is that U.S.A materials are now used in tropical breeding to accelerate earlier maturity and lodging resistance. These exotic materials, developed with U.S.A germplasm, are being introduced back into the U.S.A.Since1994, the ARS-led Germplasm Enhancement of Maize (GEM) project has sought to help broaden the genetic base of America’s corn crop by promising exotic germplasm and crossing it with domestic lines. New hybrids derived from such crosses have provided corn researchers and the producers. These may include improved or alternative native source of resistance to insect pests such as corn rootworms and diseases like northern leaf blight. GEM’s aim is to provide source of useful genetic maize diversity to help the producers to reduce risks from new or evolving insect and disease threats or changes in the environment or respond to new marketing opportunities and demand. During the 2009 growing season, the Ames (Iowa) and Raleigh (North Carolina) locations managed or coordinated evaluations on 17,200 nursery plots as well as 14,000 yield trial plots in Ames and 12,000 in Raleigh. A new “allelicdiversity” study is devoted to exploring and capturing the genetic variation represented by over 300 exotic corn races. Since 2001, GEM has released 221 new corn lines to cooperators for further development into elite commercial new hybrids. GEM has already identified about 50%-tropical, 50%-temperate families tracing primarily to tropical hybrids that are competitive with commercial checks. In North Carolina State University program, they have examined the potential of tropical inbredand hybrids for U.S.A. breeding by crossing temperate-adapted, 100%-tropical lines to U.S.A hybrids. There should be favorably unique alleles or genomic regions in temperate germplasm that can be helpful in tropical maize improvement as well as utilization of tropical lines in temperate areas.
        67.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        Among the developed bío-degradable polymer fílms as compared wíth transparent fílm(Whíte), black polymer fílm was sígnífícantly more effectíve for controllíng weeds ín red pepper. Also, we found that whíte and black polymer mulchíng had 81.8% and 97.9% of managing weed controllíng effects in rice, respectively. Compared to nonmulched rice paddy with water supply, the non-mulched rice paddy wíthout any water supply has stopped its growth at 41 days after transplantíng, whíle polymer -mulched rice paddy without water supply had about 60% of normally growing rice plants. This shows the polymer treatment has a remarkable effect on water and power saving, solution of herbicidal resistance, avoidance of herbícidal influence to eco-system etc. When the naturally decomposíng polymer was used, a temperature was elevated as high as 4.7 ℃ on maximum and 2.6 ℃ on average. Also the naturally decomposing polymer accelerated rooting by 7 days and lowered a stress level from transplanting. The weed control effect mulched by polymer was remarkable as 98. 7%. The p이ymer now, after 294 days treated on the rice paddy, has been completely decomposed.
        68.
        2011.09 서비스 종료(열람 제한)
        The development of humanized culture system of human embryonic stem cells (hESCs) hold promise for therapeutic applications. However, conventional culture system contain animal-derived components such as fetal bovine serum and mouse embryonic fibroblasts that bear a risk of transmitting non-human pathogens and incorporation of non-human immunogenic molecules to hESCs. In this study, we developed an efficient xeno-free hESCs culture system using humanized materials, the CELLstartTM, human foreskin feeder and xeno-free medium containing knockOutTM SR XenoFree (XF-medium) without animal-derived material. The hESCs were gradually adapted to the XF-medium; 25:75, 50:50, 75:25 and 100:0. Two karyotypically normal hESC lines, SNUhES4 and H1, were used for the experiments of xeno-free culture condition. The attachment rates at xeno-free culture system were 52.6±12.4%, 67.0±16.6%, 59.0±13.9%, 28.3±2.9% in SNUhES4, 79.3±5.4%, 53.8±20.9%, 69.4 ±6.4%, 59.8±12.6% in H1 and the spontaneous differentiation rates were 42.2±12.7%, 31.4±2.9%, 40.8±14.5%, 55.2±35.5% in SNUhES4, 35.6±8.5%, 36.4±13.5%, 48.4±7.8%, 80.1±6.0% in H1 in the first four passage. Although the attachment rates were low and the spontaneous differentiation rates were high compared to that of conventional system in the early passages using this humanized culture condition, hESCs in this culture condition were found to maintain hESC characterizations; morphology, expression of cell surface markers and stable karyotype. Our results indicate that simplified compositions of humanized culture system can be applicable to the further optimization for a xeno-free culture of hESCs without the loss of pluripotency and contamination from xenogenic sources.
        69.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        Cold sensitivity has been shown to vary and the cold tolerance from vegetative to reproductive stage appears to be independent during the life cycle. In the current study, cold tolerance under high elevation rice growing area were evaluated using F4 generation of 181 lines derived from Gayabyeo*2/Chhamrong. Five main-effect QTLs related to days to heading, panicle exertion and spikelet fertility were identified. The QTL qDH-3 on chromosome 3 showed the peak LOD score of 6.3, explaining up to 16.5% of phenotypic variation with additive effect of -2.6. Moreover, the QTL qPE-3 and qSF-3 on chromosome 3 were coincided with the QTL qDH-3 showing an opposite allele effects. Thus, the region harboring marker RM523-RM14281 could be helpful for the selection of cold tolerance genotypes in marker assisted selection(MAS) of rice breeding program.
        70.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        Cold tolerance at every growing stage of rice(Oryza sativa L.) is one of the main determinations for the stable growth in temperature and high elevate area. In the current study, a 181 lines of BC population derived from a cross of Gayabyeo, a Tongil type sensitive to cold and Chhamrong a tolerant to cold were evaluated for cold tolerance with cold water irrigation(17℃) at seeding stage as well as low temperature germinate at 13℃, respectively. The resulting linkage map consists of 157 marker loci, covering all of 12 rice chromosomes and spanning 910cM(Haldane function) with an average interval of 76cM between markers. Three main-effect QTLs were identified. The comparison of the OTLs identified in this cold treatments resulted in an intriquing finding that each treatments were controlled by a major QTL. The QTL qCWI-4 on chromosome 4 was found to increase its additive effect to -0.84 as the cold water irrigate stress was given. In the meanwhile, the QTL qLTG-8 was detected with a LOD score of5.54, explaining up to 13% of the phenotypic variation controlled by Gayabyeo allele. In addition, the QTL qLTGV-3, controlled by Gayabyeo allele with a LOD score of 5.19 explaining about 12.5% of the variation was also identified. These results would favor our better understanding of the genetic control of cold tolerance in rice and be important for the development of rice cultivars with a broaden climatic adaptation.
        79.
        2001.08 서비스 종료(열람 제한)
        Coleus forskohlii Briq, of the family Lamiaceae yields a valuable secondary metabolity known as forskolin which is a labdane diterpenoid.. Coleus forskohlii is the only known source of this compound. Forskolin is used in medicine for the treatment of glaucoma, congestive cardiomyopathy and asthma. Morphogenic callus was induced from young leaves on MS medium augmented with NAA and BA. These calli, when subcultured on MS with KN alone gave rise to shoots. The regenerated shoot developed good root system on MS medium fortified with NAA. The fully grown plantlets were transferred to soil for acclimatization. Coleus plant is mainly infected by a fungi Lasiodiplodia theobromae which causes root rot disease. The fungal culture filterate (ECE) of Lasiodiplodia theobromae, has been used in regeneration media to find the MIC and further to select resistant plants to the pathogen. In the present study 40% ECF in the medium showed maximum inhibition and is there fore considered as the MIC level of Coleus forshohlii. This data could prove to be useful for the future for selecting a resistant C.forskohlii plant against the root disease caused by L. theobromae.
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