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        검색결과 679

        341.
        2014.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 기존 연구와는 다른 새로운 관점에서 중국 민간기업들의 해외직접투자 입지의 결정요인에 대하여 분석하였다. 이를 위해 먼저 중국경제에서 큰 비중을 차지하고 있는 국영기업의 민영화 과정에 주목하여 현재의 민간기업들을 국영기업에서 완전한 민영기업으로 전환한 기업 (PSEs)과 설립 초기에서부터 민간기업인 기업 (POEs) 으로 분류하였다. 이어 이 두 가지 유형의 민간기업들의 속성을 분석한 후 이들이 해외직접투자를 실시함에 있어서 입지결정에 영향을 미치는 요인들, 즉 천연자원, 전략적 자산, 위험부담, 현지 중국인 네트워크 등의 변수들을 중심으로 두 유형의 기업 간 차이에 관한 가설을 설정하고 관련 2차 자료를 바탕으로 통계분석을 통하여 가설을 검증하였다. 실증분석 결과, PSEs는 POEs보다 천연자원과 전략적 자산이 풍부하고 중국인 네트워크가 덜 구축된 국가들에 더 활발히 투자하고 있는 것으로 나타났다. 이러한 연구 결과는 민간기업들을 동일한 속성을 가진 기업들로 간주하였던 기존의 연구들과는 달리 민간기업들도 유형에 따라 그 속성이 서로 다르며 해외직접투자에서도 서로 다른 입지선정 행태를 보인다는 점을 입증한 것으로 사료된다. 이 연구는 향후 갈수록 세계경제에 대한 영향이 커지고 있는 중국 민간기업의 해외직접투자에 대해 더욱 심도 있는 연구를 실시하는데 일조할 수 있을 것으로 기대된다.
        8,300원
        342.
        2014.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon nanofibers (CNFs) with diameters in the submicron and nanometer range exhibit high specific surface area, hierarchically porous structure, flexibility, and super strength which allow them to be used in the electrode materials of energy storage devices, and as hybrid-type filler in carbon fiber reinforced plastics and bone tissue scaffold. Unlike catalytic synthesis and other methods, electrospinning of various polymeric precursors followed by stabilization and carbonization has become a straightforward and convenient way to fabricate continuous CNFs. This paper is a comprehensive and brief review on the latest advances made in the development of electrospun CNFs with major focus on the promising applications accomplished by appropriately regulating the microstructural, mechanical, and electrical properties of as-spun CNFs. Additionally, the article describes the various strategies to make a variety of carbon CNFs for energy conversion and storage, catalysis, sensor, adsorption/separation, and biomedical applications. It is envisioned that electrospun CNFs will be the key materials of green science and technology through close collaborations with carbon fibers and carbon nanotubes.
        4,600원
        343.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Many automotive components for power generation such as motors and alternators have been widely using ferrite magnets. To ensure a high level of efficiency could be achieved in an alternator, the assembled magnets must be in good enough durability. Recently, some hairline cracks have been found on the magnet produced by manufacturers in Korea. Thus, there is an increasing concern that some of the magnets produced could cause further problems after being assembled in the alternator. Based on the standard alternator test (RS0008 : 2006), this paper has developed an accelerated failure-free test for magnets in alternator to demonstrate that assembled magnets will meet durability objective specified by the manufacturer. This guarantees the target life of the magnet with 90 percent reliability and 90 percent confidence level (R90C90). Temperature and rotation speed were selected as accelerated stress factors.
        4,000원
        344.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study assessed the effect of FSH and LH on oocyte meiotic, cytoplasmic maturation and on the expression level and polyadenylation status of several maternal genes. Cumulus-oocyte complexes were cultured in the presence of FSH, LH, or the combination of FSH and LH. Significant cumulus expansion and nuclear maturation was observed upon exposure to FSH alone and to the combination of FSH and LH. The combination of FSH and LH during entire IVM increased the mRNA level of four maternal genes, C-mos, Cyclin B1, Gdf9 and Bmp15, at 28 h. Supplemented with FSH or LH significantly enhanced the polyadenylation of Gdf9 and Bmp15; and altered the expression level of Gdf9 and Bmp15. Following parthenogenesis, the exposure of oocytes to combination of FSH and LH during IVM significantly increased cleavage rate, blastocyst formation rate and total cell number, and decreased apoptosis. In addition, FSH and LH down-regulated the autophagy gene Atg6 and upregulated the apoptosis gene Bcl-xL at the mRNA level in blastocysts. These data suggest that the FSH and LH enhance meiotic and cytoplasmic maturation, possibly through the regulation of maternal gene expression and polyadenylation. Overall, we show here that FSH and LH inhibit apoptosis and autophagy and improve parthenogenetic embryo competence and development.
        4,200원
        345.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 베트남산 잎말이나방족에 대한 연구를 수행하여 5종 (Adoxophyes tetraphracta Meyrick, Meridemis bathymorpha Diakonoff, Pandemis corylana Fabricius, Terthreutis bulligera Meyrick, Ulodemis hyalura Diakonoff)이 베트남에서는 처음으로 기록되었다. 모든 종에 대한 기재, 성충의 모습, 그리고 생식기의 도해를 실었다.
        4,000원
        346.
        2013.10 구독 인증기관·개인회원 무료
        The antigen GA733 is a cell-surface highly expressed glycoprotein on most human colorectal carcinomas. GA733 can be characterized as a cancer vaccine. In this study, GA733 was fused to the human immunoglobulin IgG Fc fragment to become recombinant gene GA733-Fc. Based on this, 4 recombinant genes were constructed as follows: GA733-Fc with signal peptide sequence and fusion of ER retention sequence (KDEL) (spGA733-FcK), GA733-Fc with signal sequence (spGA733-Fc), GA733-Fc fused to ER retention sequence (GA733-FcK) without signal peptide and GA733-Fc without signal peptide. Baculovirus-insect cell expression system is widely used for the high level production of recombinant proteins especially for glycoproteins. Constructed 4 recombinant genes were cloned to baculovirus express vectors. DH10Bac E.coli.-mediated transformation was used to generate recombinant bacmid DNA. Recombinant DNA was confirmed by PCR. Insect cell was transfected by bacmid to produce the recombinant baculovirus infects insect cell to produce recombinant protein. Western blot and sandwich ELISA showed the expression of recombinant proteins. Each cell lines (sf9 and HighFive) differed in recombinant proteins production level and protein secretion capability. N-Glycosylation analysis showed the function of signal peptide and ER retention sequence (KDEL). Taken together, baculovirus-insect cell system can be used to express recombinant GA733-Fc glycoproteins.
        347.
        2013.10 구독 인증기관·개인회원 무료
        Sacbrood virus (SBV) is one of the most fatal pathogens against Asian honeybee, Apis cerana. This virus cause failure of the insect larvae to pupate and death of the adult insects. This study has analyzed the host genes affected by viral infection, by comparing the expression level of host transcripts infected with or without SBV. As a first step, we sequenced the cDNA libraries of Asian honeybee by using illumina RNA sequencing. The sequences were de novo assembled to acquire honeybee transcriptome sequences. The transcriptome was annotated by the sequence comparison to known protein sequences by BLASTX and evolutionary genealogy of genes: Non-supervised Orthologous Groups (eggNOG) database with functional categories and description. By mapping the RNA-seq data to de novo assembled transcripts, we characterized the differentially expressed transcripts between SBV-infected and non-infected Asian honeybee.
        348.
        2013.10 구독 인증기관·개인회원 무료
        The novel serogroup of Bacillus thuringiensis serovar mogi (H3a3b3d) was isolated from fallen leaves, sampled in a forest region of the city of Mungyeong, Korea. Plasmids from B. thuringiensis have been implicated in pathogenicity as they carry the genes responsible for different types of diseases in mammals and insects. In this study, the genome sequence of the strain was determined. The 6.0-Mb genome of B. thuringiensis mogi contains three replicons: a circular chromosome (5.40-Mb) encoding 5,652 predicted open reading frames (ORFs), and two megaplasmids, pMOGI364 (364 564 bp) and pMOGI222 (222 348 bp). The G+C contents of these replicons ranged from 31.3% to 34.2% for pMOGI364 and pMOGI222, respectively. There are six putative cry genes, cry19Bb1, cry73Aa, cry20Bb1, cry27Ab1, cry4Aa and cry56Ba1, distributed on these two megaplasmids. To investigate the role of these genes in crystal production, the expression profiles of these toxin genes were analyzed by quantitative PCR (qPCR) from the wild type strain. Also, these cry genes were cloned to the Escherichia coli-B. thuringiensis shuttle vector, pHT1K under the control of its own promoter and then introduced into an acrystalliferous B. thuringiensis Cry-B strain for further molecular characterization.
        349.
        2013.10 구독 인증기관·개인회원 무료
        Rice stripe virus disease (RSVD), one of the most serious disease of rice is mediated through the sucking by small brown planthopper, Laodalphax striatellus. So far, the studies have been mainly focused on the interaction between the host plant and the virus. In this study, for better comprehension of the interactions among the host plant, vector insect and plant-pathogenic virus, we investigated transcriptome of the vector insect and the differences between viruliferous and naïve L.striatellus. For this, naïve L. striatellus were collected from non-infected rice field and 50 L.striatellus of them were fed RSV-infected rice for 5 days. With the RSV-viruliferous and the naïve insects, we conducted Illumina RNA sequencing (Hiseq 2000) and obtained 175,243,488 and 146,031,348 reads from viruliferous and naïve L.striatellus, respectively. These reads were assembled into contigs and two transcriptome databases were generated. The transcriptome of naïve and RSV-viruliferous L. striatellus were campared to figure out up-regulated or down-regulated genes. These RSV-dependently regulated genes may have important function in the behavior of planthoppers or the transmission of RSV.
        350.
        2013.10 구독 인증기관·개인회원 무료
        Proteinaceous insecticidal proteins, Cry proteins, from Bacillus thuringiensis (Bt) are insecticidal proteins that are highly active against several species of Lepidoptera. Thus, cry genes encoding these Cry proteins have been widely applied for construction of transgenic crops resistant to pest insects. In this study, through the 3D structure prediction and accompanying mutagenesis study for the Mod-Cry1Ac, 7 and 16 amino acid residues from domain I and II, respectively, responsible for its insecticidal activity against larvae of Spodoptera exigua and Ostrinia furnacalis were identified. We used site-directed mutagenesis to improve the insecticidal activity of Mod-Cry1Ac, resulted 31 mutant cry genes. These mutant cry genes encodes potent insecticidal proteins in the form of crystalline protoxins of 95 kDa. SDS-PAGE analysis of the recombinant polyhedra revealed that expressed Cry proteins was occluded into polyhedra and activated stably to 65 kDa by trypsin. When the insecticidal activities of these mutant Cry proteins against to larvae of P. xylostella, S. exigua and O. furnacalis were assayed, they showed higher or similar insecticidal activity compared to those of Cry1Ac and Cry1C. Especially, Mutant-N16 is considered to have the potential for the efficacious biological insecticide since it showed the highest insecticidal activity.
        351.
        2013.10 구독 인증기관·개인회원 무료
        Anatatus orientalis (Hymenoptera: Eupelmidae) is aparasitic natural enemy of the lantern-fly Lycorma delicatula (Hemiptera:Fulgoridae) in China. It can complete 6 generations from April to December in a year under laboratory conditions. It takes 18-28 d for development of one generation at about 25℃. Under the room temperatures of 23-25℃, the developmental duration of eggs is 1-2 days, 10 days for larvae, 4 days for prepupae and 7 days for pupa stage. A. orientalisis a mono-parasitic wasp in the eggs of L.delicatula and its female can oviposit 9.18 eggs on average. The oviposition period is 5-20d. The adults can survive 4-7d on average without supplying any nutrition. While feeding with 20% honey solution, the female adult longevity can reach 25 days on average.
        352.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An in vitro study was conducted to determine the effects of defaunation (removal of protozoa) and forage sources (rice straw, ryegrass and tall fescue) on ruminal fermentation characteristics, methane (CH4) production and degradation by rumen microbes. Sodium lauryl sulfate, as a defaunation reagent, was added into the mixed culture solution to remove ruminal protozoa at a concentration of 0.375 mg/ml. Pure cellulose (0.64 g, Sigma, C8002) and three forage sources were incubated in the bottle of culture solution of mixed rumen microbes (faunation) or defaunation for up to 24 h. The concentration of ammonia-N was high under condition of defaunation compared to that from faunation in all incubations (p<0.001). Total VFA concentration was increased at 3, 6 and 12 h (p<0.05~p<0.01) but was decreased at 24 h incubation (p<0.001) under condition of defaunation. Defaunation decreased acetate (p<0.001) and butyrate (p<0.001) proportions at 6, 12 and 24 h incubation times, but increased propionate (p<0.001) proportion at all incubation times for forages. Effective degradability of dry matter was decreased by defaunation (p<0.001). Defaunation not only decreased total gas (p<0.001) and CO2 (p<0.01~0.001) production at 12 and 24 h incubations, but reduced CH4 production (p<0.001) at all incubation times for all forages. The CH4 production, regardless of defaunation, in order of forage sources were rice straw > tall fescue > ryegrass > cellulose (p<0.001) up to 24 h incubation.
        4,000원
        353.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        명나방과의 2종, Hypsopygia iwamotoi Kirpichnikova & Yamanaka, 1995와 Synaphe amuralis (Hampson, 1900)이 중국에서는 처음으로 보고된다. 본 연구에서는 이들 2종에 대하여 재기재하고 성충 및 생식기의 도해도를 제시하였다.
        4,000원
        354.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Molybdenum (Mo) in rhizosphere influences sulfate assimilation as well as a number of other physiological aspects. In this study, the activity of key enzymes in sulfate assimilatory pathways, such as ATP sulfurylase (ATPs), adenosine 5'-phosphosulphate reductase (APR), as well as the responses of reactive oxygen species (ROS), were analyzed to elucidate the metabolic and physiological effects of external Mo supply to detached leaves of Trifolium repens L. Mo supply with a range from 1 mM to 40 mM depressed the activity of ATPs throughout the entire time course. In the leaves exposed to 1 mM Mo, a continuous decrease in the activity of ATPs was confirmed by Native-PAGE. The APR activity was also declined by Mo treatment. The accumulation of H2O2 and O2 were not significant up to 10 mM Mo, whereas a remarked accumulation was detected under 40 mM Mo supply. The data suggest that an external supply of Mo has an inhibitory effect on sulfate assimilation, and induces oxidative stress only at an extremely high concentration.
        4,000원
        358.
        2013.04 구독 인증기관·개인회원 무료
        울산광역시 울주군 정족산에 위치하고 있는 무제치늪은 우리나라에서 가장 오 래된 산지습지 중 하나이다. 오랜 세월에 걸친 화강암의 풍화작용과 홍수에 의한 침 식작용 등으로 형성된 분지형태의 습지로 이탄층이며 약산성의 수질을 나타낸다. 이와 같은 환경을 바탕으로 식충식물 등 희귀종이 서식하고 있으며, 곤충으로는 멸 종위기종Ⅱ급인 꼬마잠자리가 확인되는 등 생태적으로도 중요한 가치를 인정받고 있다. 본 연구에서 다양한 무제치늪의 생태계 구성원 중 육상곤충의 전체적인 서식 분포와 밀도를 조사하였으며, 시기에 따른 변화양상을 비교하였다. 조사는 2012년 6~10월에 걸쳐 5회 실시하였으며, 4개로 이루어진 무제치늪 및 주변지역 중 곤충 서식에 적합한 지점을 선택하여 정밀조사를 수행하였다. 조사방 법으로는 임의채집법(관찰, 목격, 돌들기 등), 스위핑법, 털어잡기법, 라이트트랩 법을 사용하였다. 채집한 모든 곤충을 실험실로 운반 후 동정 및 종수를 계수하였으 며 상대적 우점도지수를 구하였다. 조사결과 총 10목 67과 218종이 발견되었다. 조사된 분류군들의 군집구조를 살 펴보면 나비목이 15과 107종(R.D 49.08)으로 구성비가 가장 높았고, 그 외 노린재 목과 딱정벌레목이 14/13과 25종(R.D 11.47), 메뚜기목이 4과 16종(R.D 7.34), 파 리목이 7과 15종(R.D 6.88), 잠자리목이 4과 14종(R.D 6.42), 벌목이 5과 11종(R.D 5.05), 풀잠자리목이 3과 3종(R.D 1.38), 사마귀목과 집게레목이 1과 1종(R.D 0.46)으로 구성되었다. 주요종으로는 멸종위기종Ⅱ급인 꼬마잠자리, 국외반출승 인대상생물종인 노랑띠들명나방, 봄처녀나비가 확인되었다.
        359.
        2013.04 구독 인증기관·개인회원 무료
        Plasmids are crucial for determining the pathogenicity and host range of organisms of the Bacillus thuringiensis strains. In this research, a novel serogroup of B. thuringiensis serovar mogi (H3a3b3d), which showed mosquitocidal activity against Anopheles sinensis and Culex pipiens pallens, was isolated from fallen leaves in Mungyeong city, Republic of Korea. In contrast to the complicated plasmid profiles of B. thuringiensis H3 serotype strains, the B. thuringiensis serovar mogi contained two megaplasmids (> 30 MDa) on which the toxin genes were occasionally located. Sequence analysis using 454-pyrosequencing revealed that there are 7 putative cry genes, cry19Bb1, cry73Aa, cry40orf2, cry20Bb1, cry27Ab1, cry56Ba1 and cry39orf2, distributed on the two different megaplasmids, respectively. These cry genes were cloned to the Escherichia coli-B. thuringiensis shuttle vector, pHT1K under the control of its own promoter and p1KSD, which is a recombinant expression vector containing cyt1Aa promoter combined with the STAB-SD sequence, and then introduced into an acrystalliferous B. thuringiensis Cry-B strain for further molecular characterization. To investigate the role of these genes in crystal production, the expression profiles of these toxin genes were analyzed by quantitative PCR (qPCR) from the wild type strain. These results clearly indicate that the cry39orf2 was the dominant ingredient in the crystal. This novel 3a3b3d type strain, B. thuringiensis serovar mogi, could be used as a good resource for studying unknown mosquitocidal cry genes.
        360.
        2013.04 구독 인증기관·개인회원 무료
        ORF78 (ac78) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a baculovirus core gene of unknown function. To determine the role of ac78 in baculovirus life cycle, an ac78-deleted mutant AcMNPV, Ac78KO, was constructed. Quantitative PCR analysis revealed that ac78 is a late gene in the viral life cycle. After transfection into Spodoptera frugiperda cells, Ac78KO produced a single-cell infection phenotype indicating that no infectious budded viruses (BVs) were produced. The defection in BV production was also confirmed by both viral titration and Western blot. However, viral DNA replication is unaffected. Analysis of BV and occlusion derived virus (ODV) revealed that AC78 is associated with both forms of the virions and is a structural protein located to viral envelope. Electron microscopy showed that ac78 also plays an important role in embedding of ODV into occlusion body. This study therefore demonstrates that AC78 is a late virion associated protein and is essential for the viral life cycle.