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        검색결과 93

        41.
        2009.05 구독 인증기관·개인회원 무료
        We have determined the complete mitochondrial genome of the yellow-spotted long horned beetle, Psacothea hilaris (Coleoptera: Cerambycidae), an endangered insect species in Korea. The 15,856-bp long P. hilaris mitogenome harbors gene content typical of the animal mitogenome and a gene arrangement identical to the most common type found in insect mitogenomes. As with all other sequenced coleopteran species, the 5-bp long TAGTA motif was also detected in the intergenic space sequence located between tRNASer (UCN) and ND1 of P. hilaris. The 1,190-bp long non-coding A+T-rich region harbors an unusual series of seven identical repeat sequences of 57-bp in length and several stretches of sequences with the potential to form stem-and-loop structures. Furthermore, it contains one tRNAArg-like sequence and one tRNALys-likes equence. Phylogenetic analysis among available coleopteran mitogenomes using the concatenated amino acid sequences of PCGs appear to support the sister group relationship of the suborder Polyphaga to all remaining suborders, including Adephaga, Myxophaga, and Archostemata. Among the two available infraorders in Polyphaga, a monophyletic Cucujiformia was confirmed, with the placement of Cleroidea as the basal lineage for Cucujiformia. On the other hand, the infraorder Elateriformia was not identified as monophyletic, thereby indicating that Scirtoidea and Buprestoidea are the basal lineages for Cucujiformia and the remaining Elateriformia.
        42.
        2008.10 구독 인증기관·개인회원 무료
        This study was conducted to improve the effect of environment-friendly Tetranychus urticae pesticide through the development of Tetranychus urticae biopesticide using the plant extract. Tested extracts were fig leaf extract, viburnum erosum extract; besides Sophora flavescens Ait extract, Derris root extract, Tobacco leaf extract, and they were proved to be the caricidal effect of two spotted spider mite adults by spraying on the French bean leaf inoculated for Tetranychus urticae with each concentration; 500ppm, 200ppm, 100ppm, 50ppm. In the control treatments, caricidal effect was compared with only ‘Eungsami’ (500ppm, 200ppm, 100ppm, 50ppm), of which the main ingredient as environment-friendly organic material is, and distilled water. The caricidal effect of tested extracts to the two spotted spider mite adult was the highest in the Sophora flavescens Ait extract and Tobacco leaf extract over 90%, and comparatively low in the Derris root extract. When the caricidal effect of ‘Eungsami’ was compared with two spotted spider mite adults with each concentration, ‘Eungsami’(500ppm) and Tobacco leaf extract(500ppm) were very excellent as each 95.5%, 98.7% in treated concentration. The effect of Sophora flavescens Ait extract was also high as 96.5%. In the low concentration(50ppm), Sophora flavescens Ait extract was 45.8%, Tobacco leaf extract was the most effective as 53.8%.
        44.
        2008.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have investigated the optical properties of the global haze on Titan from spectra recorded between 7100 and 9200Åwhere CH4 absorption bands of various intensities occur. The Titan spectra were obtained on Feb. 23, 2005 (UT), near the times of the Cassini T3 flyby and Huygens probe, using an optical echelle spectrograph (BOES) on the 1.8-m telescope at Bohyunsan Observatory in Korea. In order to derive the optical properties of the haze as a function of altitude, we developed an inversion radiative-transfer program using an atmospheric model of Titan and laboratory CH4 absorption coefficients available from the literature. The derived extinction coefficients of the haze increase toward the surface, and the coefficients at shorter wavelengths are greater than those at longer wavelengths for the 30 - 120 km altitude range, indicating that the Titanian haze becomes optically thin toward the longer wavelength range. Total optical depths of the haze are estimated to be 1.4 and 1.2 for the 7270 -7360Åand 8940 -9150Å ranges, respectively. Based on the Huygens/DISR data set, Tomasko et al. (2005) reported total optical depths of 2.5 - 3.5 at 8290Å depending on the assumed fractal aggregate particle model. The total optical depths based on our results are smaller than those of Tomasko et al., but they partially overlap with their results if we consider a large uncertainty from possible variations of the CH4 mixing ratio over Titan's disk. We also derived the single scattering albedo of the haze particles as a function of altitude: it is less than 0.5 at altitudes higher than ~150Km the average particle radius is smaller than the wavelengths, whereas near the surface, it becomes comparable or greater.
        4,300원
        53.
        2004.12 구독 인증기관 무료, 개인회원 유료
        Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo. Human ES cells have the capacity to differentiate into various types of cells in the body. Human ES cells are indefinite source of cells for cell therapy in various degenerative disorders including neuronal disorders. Directed differentiation of human ES cells is a prerequisite for their clinical application. The objective of this study is to develop the culture condition for the derivation of neural precursor cells from human ES cells. Neural precursor cells were derived from human ES cells in a stepwise culture condition. Neural precursor cells in the form of neural rosette structures developed into neurospheres when cultured in suspension. Suspension culture of neurospheres has been maintained over 4 months. Expressions of nestin, soxl, sox2, pax3 and pax6 transcripts were upregulated during differentiation into neural precursor cells by RT-PCR analysis. In contrast, expression of oct4 was dramatically downregulated in neural precursor cells. Immunocytochemical analyses of neural precursor cells demonstrated expression of nestin and SOX1. When induced to differentiate on an adhesive substrate, neuro-spheres were able to differentiate into three lineages of neural systems, including neurons, astrocytes and oligo-dendrocytes. Transcripts of sox1 and pax6 were downregulated during differentiation of neural precursor cells into neurons. In contrast, expression of map2ab was elevated in the differentiated cells, relative to those in neural precursor cells. Neurons derived from neural precursor cells expressed NCAM, Tuj1, MAP2ab, NeuN and NF200 in immunocytochemical analyses. Presence of astrocytes was confirmed by expression of GFAP immuno-cytochemically. Oligodendrocytes were also observed by positive immuno-reactivities against oligodendrocyte marker O1. Results of this study demonstrate that a stepwise culture condition is developed for the derivation of neural precursor cells from human ES cells.
        4,000원
        54.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Korea is located in either low of moderate seismicity continental region. It is realized that the design codes and underlying design concept of high seismicity region may not be a, pp.opriate to low and moderate seismicity regions. The aim of this paper is to search seismic design concept that is deemed to be a, pp.opriate to low and moderate seismicity regions. To this end, the seismicity of Korea will be introduce first and important aspects of seismic design in moderate seismicity region will be discussed. The two-level code system that is going to be adopted in the future seismic regulations of Korea will be introduced.
        4,200원
        55.
        2019.03 KCI 등재 서비스 종료(열람 제한)
        최근 기후변화와 도시화로 인한 수재해 문제가 증가하고 있으며, 이에 대응방안인 저영향개발(Low-Impact Development, LID) 기법에 관한 연구가 확대되고 있다. LID 기법은 도시 내의 우수유출수를 저감시켜 다양한 수재해 문제를 친환경적으로 제어하고, 도시 개발 이전의 물순환 체계로 회복시키는 기술이다. 하지만 LID 기법에 관한 정량적 데이터가 부족한 실정이다. 따라서 본 연구에서는 저류형 LID 기술인 식생화분(Planter Box)의 Curve Number (CN)값을 산정하여, 물순환(침투, 유출, 월류수) 분석을 실시하였다. Planter Box의 물순환 분석에 관한 강우강도 시나리오(60.4 mm/hr, 83.1 mm/hr, 97.4 mm/hr, 108.2 mm/hr)는 부산시 확률강우강도표(2010)를 이용하여 선정하였다. 실험 결과는 건물화분3 (BPB-3)과 거리화분3(SPB-3)에서 우수저류율이 각각 43.5%∼52.9%, 33.4%∼39.0%로 나타났다. 또한 BPB-3에서 CN값은 평균 83이 산출되었고, Horton 침투능 곡선식 적용에 따른 우수유출효과는 17%∼96%로 나타났다.
        56.
        2018.10 KCI 등재 서비스 종료(열람 제한)
        의료용 사이크로트론은 방사성의약품을 생산하기 위해 양성자를 고속으로 가속시켜 핵반응을 일으키게 되며, 핵반응을 통해 불필요한 중성자가 발생하게 된다. 중성자는 사이클로트론의 부품에 방사화를 일으키는 원인으로 종사자들의 피폭의 원인이 된다. 이에 본 연구에서는 핵반응이 일어나는 Targetry 부품들인 Aluminum body, Silver body, Havar foil의 방사화 정도를 분석하여 피폭선량을 알아보고자 하였다. 실험결과 Aluminum body와 Silver body는 방사화된 핵종들의 에너지가 작고, 반감기가 짧아 종사들에게 미치는 선량이 미미하였으며, 재사용하는데 문제가 없었다. 하지만 Havar foil의 경우 방사화된 핵종들의 에너지가 높고 반감기가 길어 종사자들에게 미치는 영향이 매우 높았으며, 방사성폐기물로써 특별한 관리가 필용한 것으로 나타났다.
        57.
        2017.09 KCI 등재 서비스 종료(열람 제한)
        Platycodon grandiflorum (Bell flower) is an important plant that has traditionally been used as herbal medicine for the treatment of cough, phlegm, sore throats, lung abscesses, chest pains, dysuria, and dysentery. The present study was initiated to investigate the feasibility of inducing shoot and root organogenesis in cultured explants of P. grandiflorum in a range of culture media and through use of various plant growth regulators (PGRs). The plantlets (Stem containing one node) were isolated and cultured on different concentrations of Murashige and Skoog (MS) medium supplemented with PGRs. We found that proliferation and elongation of shoots and roots could be achieved on ¼ MS for P. grandiflorum with wild and green petals and on ⅛ MS for P. grandiflorum with double petals. The highest levels of development and elongation of adventitious shoots and roots were observed when petal explants were cultured on ¼ MS (pH 3.8) supplemented with 5% sucrose. Increasing the agar concentration reduced shoot growth and rooting potential; nevertheless, the highest number of shoots and roots was observed on 0.6% agar. In the case of growth regulators, ¼ MS supplemented with 1 mg L-1 6-benzylaminopurine (BA) was found to be best for shooting, although higher concentrations of BA tended to reduce shoot and root elongation. The highest number of shoots was achieved on 0.5 mg ․ L-1 thidiazuron (TDZ) from double petal explants grown on ⅛ MS. However, root and shoot elongation were found to decrease when TDZ concentrations were increased. Low concentrations of kinetin, naphthalene acetic acid, indole acetic acid, and 3-indole butyric acid induced shoot and root proliferation and elongation. Taken together, our study showed that low concentrations of PGRs induced the greatest root formation and elongation, showing that the optimal concentration of PGRs for shoot proliferation was species-dependent.
        58.
        2017.05 서비스 종료(열람 제한)
        Background : In order to develop new cultivar of hybrid kiwifruit with cold tolerance, high useful components and high quality fruit, we have been crossed ‘Hayward’ (Actinidia deliciosa) with A. arguta. The new hybrid kiwifruit cultivars were 'DM', 'HO', and 'JW'. Actinidia arguta, called hardy kiwifruit, has an edible smooth skin and contains high amounts of sugar and vitamin C. It is native to north China, Korea, and Japan. A. deliciosa are known as kiwifruit and originated in Southwest China. The fruit of A. deliciosa appreciated for its sweet, slightly acidic flesh and high nutritional value, especially due its high content in vitamin C like A. arguta. The cultivar ‘Hayward’ of A. deliciosa occupies the majority of the world kiwifruit cultivated surface, and is the cultivar commercially produced in Korea. However, the kiwifruit producing areas are limited to warm climates region, it can be cultivated in the southern parts of Korea. In our research, several hybrids have been developed to enhance cold tolerance by crossing ‘Hayward’ with domestic species. Methods and Results : In our research, several hybrids have been developed to enhance cold tolerance by crossing ‘Hayward’ with domestic species. Freeze dried the fruit of hybrid kiwifruit was finely ground, extracted twice with methanol (MeOH). The crude extracts of the fruit was analyzed with HPLC for vitamin C and β-carotene analysis. Conclusion : Moisture and carbohydrate contents of hardy kiwi fruit in this study varied from 81.40 - 83.57% and 14.63 - 16.90 g/100 g, respectively. Among new cultivars, JW had higher fat(0.17 g/100 g) and protein(1.33 g/100 g) contents than others. The highest vitamin C and β-carotene content of hardy kiwi fruit were 120.70 ㎎/ 100 g, 0.14 ㎎/kg, respectively in DM.
        59.
        2016.10 서비스 종료(열람 제한)
        Background : Despite the presence of various bioactive compounds in ginseng, there is lack of study on the variations of bioactive compounds in ginseng according to the cultivation of soil and the applied fertilizer types (or amount). Therefore, this study aims to examine the variations of 37 fatty acids (FA) and 8 vitamin E (Vit-E) vitamers in 6-year-old ginseng root cultivated in different soil types with different fertilizers regimes. Methods and Results : The profiling of 37 FAs and 8 Vit-E vitamers in 6-year-old ginseng roots was measured by gas chromatography coupled with a flame ionization detector, and then these results were statistically analyzed with chemometrics. The FA and Vit-E content in ginseng roots varied significantly with respect to soil cultivation conditions due to organic fertilizer types and amounts used. Unsaturated FA in ginseng is approximately 2.7 fold higher than the saturated FA. Linoleic, palmitic, and oleic acids were the most abundant FAs found in the ginseng roots. Also, the major Vit-E vitamer found in ginseng root is α -tocopherol. In particular, the application of rice straw compost or food waste fertilizer was increased to create nutritionally-desirable FAs and bioactive Vit-E in ginseng root. In addition, phytonutrient profiling coupled with chemometrics can be used to discriminate the cultivation conditions of ginseng. Conclusion : This preliminary study extends our understanding about the variations of FA and Vit-E in ginseng root depending on cultivation conditions. Hence, these results can be useful as basic information for reliable ginseng production containing high amounts of phytonutrients in a paddy-converted field.
        60.
        2016.10 서비스 종료(열람 제한)
        Background : Panax ginseng C. A. Meyer is a slow-growing perennial herb that is cultivated in shading condition. Climate change occur around the world that make a lot of problem such as damage of high temperature, drought, salinity and disease. The problems lower the ginseng productivity that cause income reduction of farmers. To achieve stable ginseng production, development of elite varieities resistant to abiotic and biotic stresses is consistently required. It is very time consuming process in order to develop new ginseng varieties because ginseng flowers after 3 years of growth. So, early selection system of elite line must be established. This study was conducted to develope efficient ginseng breeding techniques for early identification of heat or salinity resistance. Methods and Results : Ginseng petioles was soaked in mixed salts solution consisting of KNO3, KH2PO4, MgSO4․H2O in order to test resistant or susceptible salinity. The degree of resistance was quantified according to damage size. Also, ginseng lines transplanted in pot were treated 46℃ for 1 hour and then chlorophyll fluorescence reaction were measured in order to test resistant or susceptible high-temperature. The measured values such as Fm/Fo, Fv/Fm, Rfd were differentiated between resistant and susceptible line. Conclusion : Several lines showed that they are resistance to high temperature or salinity. The selected lines will be utilized for parents to develop new varieties.
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