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        검색결과 103

        61.
        2003.12 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate the effect of cysteamine addition during in vitro maturation, fertilization and culture of porcine oocytes. Oocytes were matured for the first 22 h in mTCM -199 media supplemented with or without 150 μM cysteamine. They then were matured for an additional 22 h in mTCM-199 media without hormones supplemented with or without 150 μM cysteamine. When cumulus-oocyte complexes (COCs) were matured in the mTCM-199 media supplemented with cysteamine, the rates of GVBD and maturation (metaphase Ⅱ) were enhanced as compared to the media without the addition of cysteamine. Also, when COCs were matured in the mTCM-199 media supplemented with cysteamine, the rates of sperm penetration, male pronucleus formation, cleavage and blastocyst formation after in vitro fertilization were enhanced as compared to the media without the addition of cysteamine. In conclusion, it was suggested that oocytes matured for the first 22 h in mTCM-199 media supplemented with 150 μM cysteamine increased the rates of metaphase Ⅱ, sperm penetration, male pronucleus and blastocyst formation were higher as compared to the media without addition of cysteamine.
        4,000원
        64.
        2003.03 구독 인증기관 무료, 개인회원 유료
        본 연구는 xanthine(X)-xanthine oxidase(XO) system하에서 돼지 난자의 체외성숙과 체외수정에 대한 catalase의 영향을 검토하였다. 그 결과 돼지 난포난자가 X 또는 XO하에서 배양되었을 때, 난포난자의 성숙율은 다른 배양시간에도 불구하고 catalase 첨가 유무에 따른 유의적인 차이를 나타내지 않았다. 그렇지만, X-XO-catalase system하에서 배양한 경우 유의적으로 높은 성숙율을 얻었다(P<0.05). 퇴행난자의 비율은 배양기간이 늘어남에 따라 증가되었으며, 배양 120시간에서는 catalase 첨가시보다 무첨가시에 유의적으로 높았다. 다른 한편으로, 단위발생 난자들이 배양 72시간에 높은 비율로 관찰되었지만, 다양한 배양시간에서 catalase 첨가유무에 따른 차이는 발견되지 않았다. 또 다른 실험에서, 동결-응해된 돼지 정자가 체외수정을 위해 X-XO system으로 처리되었다. 난자투명대에 대한 정자침입율은 none (P<0.05), XO, X+XO하에서 체외수정시 catalase 무첨가시보다 첨가시에 높게 나타났다. 다른 한편으로, 돼지정자가 none, X, XO, X+XO로 처리되었을 때, lipid peroxidation은 catalase 첨가시보다 무첨가시에 높은 비율로 나타났으며, 그 결과 정자침입과 lipid peroxidation에서의 변화가 상반되는 양상을 보였다. 그렇지만, 모든 조건하에서 정자의 sulfhydry (-SH) group의 함량은 catalase 첨가시에 높게 측정되었다. 난자의 투명대에 대한 정자의 접착 정도는 salt-stored 돼지 난자에 대한 정자접착을 통해서 평가되었으며, control group의 경우 X, XO, X+XO group에 비해 높은 정자접착율이 관찰되었다. 그렇지만, catalase 첨가유무에 따른 유의적인 차이는 인정되지 않았다. 본 연구의 결과는 X-XO-catalase system에 대한 난포난자와 정자의 노출이 돼지에서의 체외성숙과 체외수정을 촉진시키는 것으로 생각된다.
        4,000원
        69.
        2001.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lithium intercalated carbon (LIC) are basically employed as an anode for currently commercialized lithium secondary batteries. However, there are still strong interests in modifying carbon surface of active materials of the anode because the amount of irreversible capacity, charge-discharge capacity and high rate capability are largely determined by the surface conditions of the carbon. In this study, the carbonaceous materials were coated with tin oxide and copper by fluidized-bed chemical vapor deposition (CVD) method and their coating effects on electrochemical characteristics were investigated. The electrode which coated with tin oxides gave the higher capacity than that of raw material. Their capacity decreased with the progress of cycling possibly due to severe volume changes. However, the cyclability was improved by coating with copper on the surface of the tin oxides coated carbonaceous materials, which plays an important role as an inactive matrix buffering volume changes. An impedance on passivation film was decreased as tin oxides contents and it resulted in the higher capacity.
        4,000원
        72.
        2000.06 구독 인증기관·개인회원 무료
        Non-stoichiometric ceramics of were prepared by self-propagating high temperature synthesis reaction with various processing conditions and their stoichometric numbers were determined by neutron diffraction. The neutron diffraction patterns were measured at room temperature using monochromatic neutrons with a wave length of 0.18339 nm from a Ge(331) mocochromator at a 90 degree take off angle. The Rietveld refinement of each pattern converged to good agreement (x2=1.88-2.24). The neutron diffraction analysis revealed the final stoichiometries of the ferrites were and respectively. This supports that final stoichiometric number of the self-propagating high temperature synthesis product can be controlled by the processing parameters during the combustion reaction.
        77.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        In the present work we introduce a new flare activity indicator, MAD and examine its characteristics by analyzing a set of successive three days' observations of a typical active region, AR2372. The computed MAD is compared with conventional activity indicator such as separator. It is found that. (1) MAD traces very well the separator, (2) it. singles out. local discontinuity of magnetic field lines and (3) it. is a good measure of describing the evolutionary status of active region.
        78.
        1995.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        긴덜이리응애와 dicofol 저항성 및 감수성 점박이응애에 대한 아바맥틴의 선택독성을 실험실 내에서 엽침지법으로 조사하였다. 아바멕틴은 긴털이리응애에 대해서는 독성이 낮은 반면, 점박이응애에 대해서는 살균효과가 높았다. 0.12 ppm과 0.6 ppm의 농도에서 점박이응애는 두 계통 모두 침지 후 48시간 0]내에 사망하였고, 0.06 ppm과 0.012 ppm의 낮은 농도에서 120시간 이후에는 77% 이상이 사망하였다. 그러나긴털이리응애의 암컷성충은 0.12ppm에서는 생존솔과 활동력이 영향을 받지 않았고, 0.6ppm과 6ppm의 높은 농도에서도 사망솔이 약 20~23%이었다. 아바맨틴은 산란후 l일 이내의 점박이응애의 난에 대해서는 패화솔에 영향을 미치지 않았으나 산란후 4일된 란에서는 패화솔이 멸소하였다. 반면에0.006-6ppm 용액에 긴털이리응애 난을 침지한경우 난의 패화솔과 그 난에서 부화한 약충의 발육에는 영향이 없었다. 긴털이리응애의 암컷 성충을 0.6 ppm과- 0.12ppm에 침지했을 때 산란수가 줄어들지 않았으나 잠박이응애의 산란수는0.006-0.6 ppm의 농도에서 현저히 감소하였다. 이상과 같이 아바맥틴은 점박이응애와 긴털이리응애에 대한 선택독성이 높은 약제로 점박이응애의 결합방제에 유용하게 이용될 수 있을 것으로 생각되며, 점박이응애에 대한 아치사농도(0.012-0.06 ppm)는 긴털이리응애와 점박이응애의 밀도를 조사하는데 이용될 수 있을 것으로 생각된다.
        4,000원
        79.
        2013.07 서비스 종료(열람 제한)
        We investigated whether sound could alter gene expression in plants. Using a sound-treated subtractive library, a set of sound-responsive genes in plants was demonstrated through mRNA expression analyses. Of them, the rbcS and ald genes, which are light responsive, up-regulated their expression with sound treatment in both light and in dark conditions. This suggested that sound could be used as a gene regulator instead of light. When we analyzed ald gene expression using various single wavelengths, a significant increase in mRNA levels was found at 125 or 250 Hz but decreased at 50 Hz, indicating that the gene responded to sound in a wavelength-specific manner. To determine whether the ald promoter respond to sound, we generated transgenic rice plants harboring the chimeric gene consisting of a 1,506-bp promoter fragment of the ald gene fused to Escherichia coli GUS reporter gene. Analyses of mRNA expressison level of three independent transgenic lines sound-treated with 50 or 250 Hz for 4 h showed that the Gus gene expression in all three transgenic lines was up regulated by 250 Hz, but down regulated by 50 Hz. These results correlated with sound responsive mRNA expression pattern observed for the ald gene in rice plants, indicating that the 1,506-bp ald promoter confers sound-responsiveness on a reporter gene in transgenic rice plants. We also investigated whether sound waves could improve salt tolerance in rice seedling. The rice seedlings were sound treated with 800 Hz for 1hr, and then treated with 0, 75, 150, and 225mM NaCl for 3 days to observe changes in physiological and morphological aspects. Sound treatment seedlings resulted in enhanced salt stress tolerance, mainly demonstrated by the sound treated seedlings exhibiting of increased root relative water contents (RWC), root length and weight, photochemical efficiency (ratio of variable to maximum fluorescence, Fv/Fm), and germination rate under salt stress condition. This demonstrates that a specific sound wave might be used, not only to alter gene expression in plant, but also to improve salt stress tolerance.
        80.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        Environment friendly agricultural material products (EFAMs) in current market were evaluated for their insecticidal or acaricidal activities. EFAMs were evaluated against Tetranychus urticae, Plutella xylostella, Myzus persicae and Nilaparvata lugens in spray method. Several EFAMs indicated high control value in spray method. Hatchability of T. urticae was relatively high after EFAM treatment. some materials show high insecticidal activities against P. xylostella larvae but not against eggs. Few meterials showed more than 80% insecticidal activities against M. persicae and N. lugen. The control value of more than half the materials for pest control was lower than 60%. EFAMs containing S. flavescens, neem oil and Rape showed higher control value
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