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        검색결과 32

        1.
        2023.11 구독 인증기관·개인회원 무료
        It has been known that as oxide layer (ZrO2) forms on the nuclear fuel cladding during irradiation in nuclear power plants, the corrosion kinetics are influenced by various parameters such as chemical environments. One of those environments, crud deposition driven by coolant chemistry has an adverse effect on the formation of oxide (ZrO2) and leads to increase thickness of the layer. In this study, crud formation was performed through loop experiment equipment on the surface of intentionally-made oxide layer (ZrO2) on cladding tubes and then the composition and characteristics of cruds were examined for the investigation of nuclear power plant environment. As a result, various cruds in composition and microstructure were formed depending on the exquisite methods and conditions such as metal ion concentration.
        3.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        공공정원이 현대도시의 새로운 영역으로 등장하며 시민가드너 양성교육이 확대되는 현상에 주목하여, 시민가드너 교육 참가자, 참여의향자, 일반시민으로 집단을 구분하여 도시정원에 대한 이미지와 효과 및 공동체성을 분석하여 다음과 같은 결과를 도출하였으며, 교육 의의 및 활성화 방안을 함께 고찰하였다. 24개 형용사 어의구별척도를 이용한 도시정원 이미지 평가 결과, 자연과의 관계를 나타내는 “친숙한, 정서적인” 등의 어의변수와 정원활동에 대한 태도를 나타내는 “상호교류적인, 적극적인”, 그리고 공간적 평가와 관련된 “확장적인, 자율 적인” 이미지에서 상대적으로 높은 평가치를 보였다. 교육참 가자는 “자율적인, 지속적인” 등의 어의변수를 높게 평가하여, 도시정원의 형태나 디자인보다는 유지관리와 지속성을 중시함을 알 수 있었다. 주성분분석에 의한 요인분석 결과로부터 교육참가자 집단의 요인적재값을 중심으로 요인별 특성을 파악하면, 잠재적(Potential) 차원의 1 요인은 “도시정원의 공공적 역할과 공동체성”, 평가적(Evaluative) 차원의 2 요인은 “공공조경으로서의 차별성”, 활동적(Active) 차원의 3 요인은 “미적 체험성”으로 명명할 수 있었다. 도시정원 효과에 대해 교육 참가자일수록 사회적, 환경적 측면을 중요하게 인식하고 있었고, 공동체의식지표 평균값(3.4)은 잠재참가 집단(3.31)과 일반시민 집단(2.69)에 비해 높게 나타났다는 점에서 공공성 인식 상의 차이를 볼 수 있었다. 시민가드너 교육이 정원식물 지식 습득의 의미를 넘어 평생교육이나 공동체 활동으로 인식 된다는 점에서 지속가능성을 위한 교육의 체계화 필요성을 확인할 수 있었다.
        4,000원
        5.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to identify key nations and bird species of conservation concern we described multinational collaborations as defined using network analysis linked by birds that are found in all nations in the network. We used network analysis to assess the patterns in bird occurrence for 10,422 bird inventories from 244 countries and territories. Nations that are important in multinational collaborations for bird conservation were assessed using the centrality measures, closeness and betweenness centrality. Countries important for the multinational collaboration of bird conservation were examined based on their centrality measures, which included closeness and betweenness centralities. Comparatively, the co-occurrence network was divided into four groups that reveal different biogeographical structures. A group with higher closeness centrality included countries in southern Africa and had the potential to affect species in many other countries. Birds in countries in Asia, Australia and the South Pacific that are important to the cohesiveness of the global network had a higher score of betweenness centrality. Countries that had higher numbers of bird species and more extensively distributed bird species had higher centrality scores; in these countries, birds may act as excellent indicators of trends in the co-occurrence bird network. For effective bird conservation in the world, much stronger coordination among countries is required. Bird co-occurrence patterns can provide a suitable and powerful framework for understanding the complexity of co-occurrence patterns and consequences for multinational collaborations on bird conservation.
        4,000원
        6.
        2017.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        에너지 음료는 카페인을 주성분으로 타우린, 비타민 같은 다른 energy-enhancing 성분을 함유하고 있다. 미국과 유럽에서는 글루쿠로노락톤이 에너지 음료에 첨가될수 있으나, 국내에서 의약품으로는 허가되어 있다. 따라서 식품 첨가물로는 그 사용이 금지 되어 있어, 지속적으로 수입 및 유통 음료에서 시험검사를 하여 규제하고 있다. 현재 분석법으로 사용하는 LC-PDA 법은 복잡한 유도체화 과 정을 거치고, 음료 중에 당류들이 위양성 결과를 나타내 기도 한다. 이런 기존 방법의 단점을 개선하기 위해 HILICESI- MS/MS (hydrophilic interaction liquid chromatography coupled to electrospray ionization tandem mass spectrometry) 를 이용한 분석법을 개발하고, 선택성, 직선성, 검출한계, 정량한계, 정밀도, 정확성, 재현성에 대하여 분석법 유효성 검증을 수행했고, AOAC, EURACHEM 가이드라인에 부합되는 결과를 얻었다.
        4,000원
        7.
        2016.10 구독 인증기관 무료, 개인회원 유료
        We determined the effects of different water temperatures (15, 20, and 25℃) and photoperiod cycles (24L:0D, 12L:12D, and 0L:24D) on the oxygen consumption of the offspring of a cultured Japanese strain (JJ), a selected Korean strain (KK), and intraspecific hybrid strains (JK and KJ) of red seabream, Pagrus major, under starvation conditions. The different fish strains, water temperatures, and photoperiod cycles had effects on the mean oxygen consumption of fish. Oxygen consumption increased with increasing water temperatures for all photoperiod treatments (p <0.001). Fish held in continuous darkness (0L:24D) used consistently less oxygen than fish exposed to continuous light (p <0.05). The oxygen consumption of fish exposed to the light phase in a 12L:12D photoperiod was higher than that of fish in the dark phase of the 12L:12D cycle, and differences were significant in three of the strains: JJ (15℃), KK (15 and 20℃), and KJ (25℃). The oxygen consumption of the inbred (JJ and KK) and intraspecific hybrid (JK and KJ) strains varied with differing water temperatures and photoperiod cycles. The JK strain displayed significantly higher oxygen consumption than the other strains under all experimental conditions except 15℃ with a 0L:24D photoperiod. The JK and KJ strains usually showed the highest and lowest oxygen consumption values, respectively, whereas the inbred strains exhibited intermediate values. Oxygen consumption in the JJ and JK strains was usually higher than that of the KK and KJ strains. We propose that differences in the thermal sensitivity and photosensitization properties of the strains contribute to differences in their ability to adapt to changes in water temperature and photoperiod, thus resulting in differences in the amplitude of their metabolic rates.
        4,000원
        10.
        2014.10 구독 인증기관·개인회원 무료
        Porcine parvovirus (PPV), a member of the genus Parvovirus, family Parvoviridae, is a significant causative agent in porcine reproductive failure, causing serious economic losses in the swine industry. PPV is a non-enveloped virus and its capsid is assembled from three viral proteins (VP1, VP2, and VP3). The major capsid protein, VP2 is the main target for neutralizing antibodies in PPV. When VP2 was expressed in large amounts, it assembled into virus-like particles (VLPs) similar in size and morphology to the original virions. In this study, we generated the recombinant Bombyx mori nucleopolyhedrovirus (BmNPV) to express the VP2 protein. Expression of the VP2 protein was analyzed by SDS-PAGE and Western blot. The recombinant VP2 protein of approximately 64 kDa was detected by both analyses. The formation of VLP by recombinant VP2 was confirmed through transmission electron microscopy examination. The purified VP2 protein assembled into spherical particles with diameters ranging from 20 to 22 nm.
        11.
        2013.04 구독 인증기관·개인회원 무료
        The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is widely utilized for greenhouse pollination in South Korea. Understanding the magnitude of genetic diversity and geographic relationships is of fundamental importance for long term preservation and utilization. As a first step, we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to the “DNA barcode” region and the complete internal transcribed spacer 2 (ITS2) of nuclear ribosomal DNA from 88 individuals collected in nine South Korean localities. The complete ITS2 sequences were longest among known insects, ranging in size from 2,034 bp ~ 2,052 bp, harboring two duplicated 112-bp long repeats. The 658-bp long mtDNA sequences provided only six haplotypes with a maximum sequence divergence of 0.61% (4 bp), whereas the ITS sequences provided 84 sequence types with a maximum sequence divergence of 1.02% (21 sites). The combination of the current COI data with those of published data suggest that the B. ignitus in South Korea and China are genetically a large group, but those in Japan can be roughly separated into another group. Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population were found to exist among the South Korean populations of B. ignitus, which suggests panmixia. This finding is consistent with our understanding of the dispersal capability of the species.
        12.
        2012.10 구독 인증기관·개인회원 무료
        Among hemipteran insects which is the most important insect vector of plant viruses, small brown planthopper, Laodelphax striatellus, transmits the rice stripe virus (RSV) causing rice stripe disease. For effective control of RSV, it is important to understand interaction between RSV and L. striatellus. Therefore, in this study, expressed sequence tag (EST) databases were generated based on 454 GS-FLX pyrosequencing for comparative transcriptome analysis between nonviruliferous and RSV-viruliferous L. striatellus. By comparing the two EST libraries, we showed that 108 host genes were significantly up-regulated and 28 host genes were significantly down-regulated in viruliferous insects. Interestingly, genes encoding ribosomal proteins were mainly up-regulated in viruliferous L. striatellus, whereas genes related to translation were concentrated in the downregulated cohort. These RSV-dependently regulated genes may have important function in the behavior of planthopper or the transmission of RSV.
        13.
        2012.05 구독 인증기관·개인회원 무료
        In the transcriptome surveys of Laodelphax striatellus, several cDNA sequences showed a high level of similarities to the insect picorna-like virus genomes. Interestingly, there was no sequence similarity between picorna-like virus sequences from the RSV-viruliferous and those from the non-viruliferous L. striatellus. Picorna-like virus from the non-viruliferous L. striatellus was a geographical isolate of Himetobi P virus (HiPV). The genome of the HiPV was 9,272 nt in length excluding the poly(A) tail and contained two open reading frames (ORFs), which were separated by a 176 nt intergenic region that functions as an internal ribosome entry site (IRES). The 5' ORF encodes the non-structural proteins and the 3' ORF encodes the capsid proteins. The partial genomic RNA of the picorna-like virus from the RSV-viruliferous L. striatellus, LsPV-2, was 8,769 nt in length excluding the poly(A) tail and contained a single, large open reading frame (nt 1–8,535) encoding a 2,845 aa polyprotein. In terms of sequence similarity, identity, and genome organization, LsPV-2 resembled insect picornalike viruses belonging to the family Iflaviridae. A phylogenetic analysis based on RNA-dependent RNA polymerase (RdRp) sequence showed that LsPV-2 was most closely related to the deformed wing virus (DWV). The HiPV and LsPV-2 were incompatible each other in L. striatellus, suggesting that these two picorna-like viruses may have important functions in transmission of the RSV.
        14.
        2011.10 구독 인증기관·개인회원 무료
        Rice stripe virus (RSV), the type member of the genus Tenuivirus, causes rice stripe disease and the viral transmission is mediated through the sucking by small brown planthopper, Laodelphax striatellus. Considerations have been mainly focused on the protection of rice from RSV and/or the planthopper, rather than the interaction between RSV and the insect. To clarify the interaction, in this work, mRNA was extracted from RSV-viruliferous planthopper with non-viruliferous control, and expressed sequence tag (EST) databases were generated based on 454 GS-FLX pyrosequencing technology for comparative analysis. RSV-viruliferous planthopper had ca. 2500 isotigs, which included genes on biological process (19%), cellular component (13%), molecular function (22%) and no hits (46%) from gene ontology (GO) analysis; this structure was similar to the control. However, in the viruliferous planthopper, 109 isotigs were up-regulated and 660 isotigs were down-regulated, compared to the non-viruliferous control. These RSV-dependently regulated genes may have important function in the behavior of planthopper or the transmission of RSV.
        15.
        2010.10 구독 인증기관·개인회원 무료
        Bee venom contains a variety of peptides and enzymes, including serine proteases. While the presence of serine proteases in bee venom has been demonstrated, the role of these proteins in bee venom has not been elucidated. Furthermore, there is currently no information available regarding the melanization response or the fibrin(ogen)olytic activity of bee venom serine protease, and the molecular mechanism of its action remains unknown. Here we show that bee venom serine protease (Bi-VSP) is a multifunctional enzyme. In insects, Bi-VSP acts as an arthropod prophenoloxidase (proPO)-activating factor (PPAF), thereby triggering the phenoloxidase (PO) cascade. Bi-VSP injected through the stinger induces a lethal melanization response in target insects by modulating the innate immune response. In mammals, Bi-VSP acts similarly to snake venom serine protease, which exhibits fibrin(ogen)olytic activity. Bi-VSP activates prothrombin and directly degrades fibrinogen into fibrin degradation products, defining roles forBi-VSP as a prothrombin activator, a thrombin-like protease, and a plasmin-like protease. These findings provide a novel view of the mechanism of bee venom in which the bee venom serine protease kills target insects via a melanization strategy and exhibits fibrin(ogen)olytic activity.
        16.
        2009.10 구독 인증기관·개인회원 무료
        We report for the first time the occurrence of DWV-infected bumble bees (Bombus ignitus). For the present study, the detection of DWV virus from the female and male bumble bee was investigated in the same colony. The Deformed wing virus (DWV) of honeybee (Apis mellifera) is closely associated with characteristic wing deformities, abdominal bloating, paralysis, and rapid mortality of emerging adult bees. Using specific RT-PCR protocols for the detection of DWV followed by sequencing of the PCR products we could demonstrate that the bumble bees were indeed infected with DWV. The virus was detected from Bombus ignitus, and its partial DWV gene was cloned and sequenced. The partial DWV gene encoding the polyprotein is 711-nt of 235 amino acid residues. The deduced nucleotide sequence of the polyprotein partial gene of DWV showed 96.9%, 96.2%, 96.8%, and 96.5% homology to other structure polyprotein partial gene of DWV from insects, respectively. Phylogenetic analysis further conformed that the deduced nucleotide sequence of the polyprotein partial gene of DWV divided to the outside tree. We describe the first time that presence of Deformed wing virus(DWV) from bumble bee(Bombus terrestris) in korea using RT-PCR.
        17.
        2009.10 구독 인증기관·개인회원 무료
        Bee venom contains a variety of toxic enzymes and peptides. One of the major components of bumblebee venom is bombolitin, which is the most abundant venom constituent and biologically similar to melittin. Here, we first show the molecular cloning and antimicrobial activity of the venom bombolitin from the bumblebee Bombus ignitus. The B. ignitus venom bombolitin gene consists of 2 exons, encoding 56 amino acid residues. The bombolitin purified from B. ignitus venom was the 2104 Da mature peptide with 18 amino acid residues, which are created by cleavage of the probombolitin domain between Ala38 and Leu39. We examined the pattern of bombolitin expression to confirm that it is a component of bumblebee venom. B. igniutus venom bombolitin exhibits venom gland-specific expression. We also investigated the venom bombolitin for antimicrobial properties against bacteria and fungi. The venom bombolitin showed high antibacterial activity against both Gram-negative and Gram-positive bacteria. Most interestingly, the venom bombolitin showed high antifungal activity against Fulvia falva, a leaf mold, and Alternaria radicia, a black rot. These antimicrobial profiles of B. ignitus venom bombolitin reported herein will be useful in the application for potential antimicrobial agents.
        18.
        2008.05 구독 인증기관·개인회원 무료
        To understand geographic genetic variation of the species and relationships among populations of the bumble bee, Bombus ardens, we sequenced a portion of mitochondrial COI gene, which corresponds to "DNA Barcode" region (658 bp) from 101 B. ardens individuals collected over 11 localities in Korea. The sequence data were used to investigate genetic diversity within populations and species, geographic variation within species, phylogeographic relationship among populations, and phylogenetic relationship among haplotypes. A total of nine haplortpes were found, but they very close to each other (a maximum sequence divergence of 0. 304%). Summarized, overall moderate to low genetic diversity within populations and species was characteristic, concordant with the high potential to disperse of B. ardens in Korea. There was no clear regional subdivision was observed and relatively high rate of gene flow among localities and low FST was characteristic.
        19.
        2007.12 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to prepare bioactive ginseng yogurts containing compound K, which is transformed from ginsenosides, and to investigate the compound’s cytotoxicity against tumor cells. Milk containng ginseng was fermented by Bifidobacteria KK-l and KK-2, and their activities for transforming ginsenosides to compound K were measured. Among the tested concentrations of ginseng in the milk, compound K was effectively produced in the 3% and 6% ginseng yogurts fermented for 48 hrs. These fermented ginseng yogurts were extracted with BuOH, and their cytotoxicities against tumor cells were examined. The BuOH extract of the yogurt made from the 3% ginseng milk showed cytotooxic activity against P388 and HeLa tumor cells. However, the nonfermented ginseng milk did not exhibit cytotoxicity against these cells. Therefore, we deem that the ginseng yogurt, which contained compound K, could be developed as a potential fermented drink product.
        3,000원
        20.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Potato (Solamum tuberosum 'Dejima') plantlets were investigated on culture type and initial quantity of inoculation in bioreactor and survival rate by hydroponics for mass production. rode stems (1 to 1.5cm in length) of potato plantlets multiplied in vitro were grown for 3 weeks in liquid Murashige and Skoog (MS) medium with sucrose 30 g L-1. When plantlets (80-node inoculation) were raised in 10L balloon type bubble (BB) bioreactor, the healthiest growth of plantlets was obtained from explants cultured in ebb & flow culture with medium supplied periodically 12 times per day. The suitable inoculation quantity of 20L BB bioreactor was 120 pieces of stem segments (mean 2.2g fresh weight) in ebb & flow culture. Number of nodal shoot was eight on the average. In controlled culture room, survival rate of plantlets at 7 days after stem cutting was above 70% when they were acclimatized by hydroponics grown in deep flow and solid medium culture. The highest survival rate of the stem cutting plantlets was in nutrient solution adjusted to EC 1.4dS·m-1. Stem cutting plantlets through one culture could be obtained 670~900, when plantlets were grown in ebb & flow culture during 3 weeks using a 20L bioreactor with initial 120 pieces of nodal segments. 11 is possible In do mass production of seedlings cultured in bioreactor and hydroponics.
        3,000원
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