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        검색결과 133

        21.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        낙동강 상류의 지류이며, 국내 대표적인 모래하천으로 잘 알려진 내성천 상류에 위치한 영주댐을 기준으로 하류 지점과 상류 지점을 선정하여, 2015년과 2016년동안 담수화에 따른 저서성대형무척추동물의 서식유형 및 군집구조의 변화 양상에 대한 분석을 실시하였다. 조사는 댐의 건설이 저서성대형무척추동물에 미치는 영향을 파악하고자 2015년, 2016년 총 4회에 걸쳐 실시하였다. 조사 결과, 댐에 의한 내성천의 담수화가 2016년 7월부터 진행됨에 따라 전체 출현 종수가 감소하였다. 특히 댐에서 가까운 상류 지점인 St.2와 St.3에서 감소 폭이 크게 나타났다. 유수성 환경과 입자가 큰 하상구조를 선호하는 E.P.T. 분류군의 종조성 비율은 감소하고, 정수역 환경을 선호하는 O.C.H. 분류군의 종조성 비율은 증가한 것으로 확인되었다. 서식기능군은 담수가 진행됨에 따라 붙는무리 (CL; Clinger)의 종수 및 개체수 비율이 모든 지점에서 감소하였고, 굴파는무리 (BU; Burrower), 기어오르는무리 (CB; Climber), 기는무리 (SP; Sprawler), 헤엄치는 무리 (SW; Swimmer)의 종수 및 개체수 비율이 증가하였다. 또한 서식환경 변화에 따른 군집안 정성을 비교 결과, group I (높은 저항력, 높은 회복력)의 종 분포는 크게 변화하지 않았으나 St.2와 St.3에서 group II (높은 저항력, 낮은 회복력)의 종 출현율이 현저히 감소하는 것으로 나타났다. 본 연구를 통해 댐 건설로 인해 담수가 진행됨에 따라 저서환경변화와 유속에 영향을 직접적으로 받는 저서성대형 무척추동물의 서식유형과 군집구조에 대한 시간적, 공간적 변화 양상을 확인할 수 있었다. 또한 향후 내성천 수계의 지속적인 모니터링을 통해 댐 건설과 이로 인한 담수의 진행 정도에 따라 저서성대형무척추동물 군집구조 변화와 서식기능군은 물론 섭식기능군의 변화 양상에 대한 체 계적인 연구가 요구된다. 그리고 댐 조성이 하천생태계 저서성대형무척추동물의 분포 및 서식양태 변화에 미치는 영향에 대한 추가적인 조사 및 연구가 필요할 것으로 판단 된다.
        4,000원
        22.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 건강기능식품 프랑스해안송껍질추출물 중 catechin, caffeic acid, ferulic acid, taxifolin에 대한 동시분석법을 개발하는 연구이다. 최적분석조건을 확립하기 위해 시료 채취량, 용매 조건을 비교 검토하였으며, UPLCMS/ MS를 이용하여 각 4개 성분에 대한 정확한 분석 및 분석시간의 효율성도 향상하였다. 분석 시 사용한 컬럼은 Acquity UPLC BEH C18이며, 정량이온으로 catechin, caffeic acid, ferulic acid, taxifolin 각각 133, 135, 245 및 248을 선정하였다. 확립된 시험법에 대해 특이성, 직선성, 검출한계, 정량한계, 정확성, 정밀성 등의 밸리데이션을 수행하였다. 4개 성분 모두 50-25000 mg/L 농도에서 결정계수(R2) 0.999이상으로 높은 직선성을 확인하였다. 또한 회수율은 84.9-104%이었고, 정밀성은 1.2-4.3%의 RSD를 확인하였다. 개발된 시험법은 프랑스해안송껍질추출물 중 catechin, caffeic acid, ferulic acid, taxifolin 분석을 위한 시험법으로 활용되기에 적합한 것으로 판단된다.
        4,000원
        23.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 실험의 목적은 간척지 토양에서 다른 EC처리에 따라 향부자와 갯방풍의 생장 및 기능성물질 차이를 분석 하고자 수행하였다. 향부자와 갯방풍 종자를 트레이에 파종 후 8주간 온실에서 육묘하였고 새만금 지역에서 채취한 간척지 토양을 담은 포트에 이식하였다. 식물은 EC농도에 따라, 대조구, 1, 2, 4, 8dS·m-1 조건으로 12주 간 실험을 진행했고 추가로 간척지 토양에서의 EC 1dS·m-1 과 원예용 상토를 구분하여 생육을 비교했다. 향부자의 초장, 엽장 엽폭은 EC 1dS·m-1 에서 가장 높 았다. 엽수, 화방 수, 인편 수는 EC 2dS·m-1 에서 가장 크고 EC 8dS·m-1에서 가장 적었으며, SPAD는 EC 2와 4dS·m-1 에서 가장 높고 EC 8dS·m-1에서 가장 낮았다. 지상부와 지하부의 생체중은 EC 2dS·m-1 까지 증가하다 가 농도가 증가함에 따라 값이 감소했다. EC 1dS·m-1 조건에서 간척지토양과 원예용 상토에서 자란 작물의 생육을 비교했을 때 SPAD, 엽수, 화방 수, 인편 수, 지상부 와 지하부의 생체중은 원예용 상토에서 더 높았다. 갯방 풍은 모든 생육 조건에서 EC 8dS·m-1가 가장 낮았으며 EC 8dS·m-1을 제외하고 다른 처리구에서는 유의적인 차이를 확인할 수 없었다. 향부자는 EC 1dS·m-1에서 pcoumaric acid 함량이 가장 높았고, 갯방풍의 지상부는 catechin의 함량이 대조구에서 가장 높았으며 지하부는 EC 1dS·m-1에서 benzoic acid 함량이 가장 높았다. 간척지 토양을 EC 4dS·m-1 이내로 관리 할 수 있다면 향부 자와 갯방풍의 재배가 가능할 수 있을 것으로 판단된다.
        4,000원
        27.
        2018.10 구독 인증기관·개인회원 무료
        The multicolored Asian ladybeetle Harmonia axyridis is characterized by polymorphism of the elytral pattern. Melanization in Harmonia axyridis is crucial for their elytral coloration, but the molecular mechanisms are not fully understood in this species. Tyrosine hydroxylase (TH) and dopa decarboxylase (DDC), two key enzymes in the melanin pathway, convert tyrosine and dopa into dopa and dopamine, respectively. In this study, it was to determine the role of TH and DDC of Harmonia axyridis (HaTH and HaDDC) in body and wing pigmentaion produced via melanin pathway. The cDNA sequences of HaTH and HaDDC were cloned to perform RNAi-based functional analysis. Injected dsRNA to the 4th larvae caused knockdown of target genes, and it was verified by quantative realtime PCR. Both TH and DDC RNAi adult show loss of black pigmentation in their body and wing pigmentaion. These results is expected to be helpful to investigate polymorphism by melanin pigment in Harmonia axyridis.
        28.
        2018.10 구독 인증기관·개인회원 무료
        Host defense against pathogen invasion highly relies on immune defense machinery that is controlled by the nuclear factor-κB (NF-κB) of transcription factors. The Toll pathway are well known as an insect innate immune mechanism to protect host itself from invaded pathogens. Basically, in the edible insect, Tenebrio molitor, the Toll pathway is primarily activated by polymeric Lys-type peptidoglycans (PGNs), and components of fungal cell walls, β-1,3-glucan. Based on the current studies, the tremendous study has been focused on recognition and subsequent activation of spätzle in haemolymph, hence, there is a grave gap for intracellular event. Herein, in order to understand intracellular event of Toll signaling pathway, the Dorsal gene were identified. Moreover, domain analyses of TmDorsal2 gene indicate that there are two major domains such as Rel homology domain (RHD), ig-like, plexins, and transcription factors (IPT) domains. Based on the achieved results, TmDorsal2 mRNA was highly expressed in 1-day old pupa. Furthermore, TmDorsal2 was highly expressed in Malpighian tubules and fat body in last instar larvae (LL), and likewise mainly expressed in Malpighian tubules during adult 5-day old period, also the lowest expression of TmDorsal2 was observed in gonads. Moreover, TmDorsal2 mRNA levels after infection with E. coli appreciably went up at 6 and 9h time points. To investigate the effects of TmDorsal2 RNAi on larval susceptibility against various pathogens namely E. coli, S. aureus or C.albicans, dsRNA of TmDorsal2 has been synthesized the larvae dissected after 24h. As a result, TmAttacin1a, 1b and 2, TmDefencine1 and 2, TmTenecin1, 2, 3 and 4, TmCecropin2, TmColeoptericin1 and 2, Thaumatin-like protein 1 and 2 markedly reduced in the gut after injecting all mentioned microbes. In contrast, TmTenecin 2, Thaumatin-like protein 1 and 2 strikingly increased after microbe injection in the fat body. Interestingly, the most AMPs gene expression in whole body experimental case were upregulated. On the horizon, we will investigate effects of TmDorsal1 RNAi on larval susceptibility against various pathogens. Taken together, our studies may aid to understand insect innate immunity.
        29.
        2018.09 구독 인증기관·개인회원 무료
        Glutathione S-transferase (GST) is a key gene involved in multiple stress tolerance in all living organisms, though it is still to be disclosed the gene function in teff grass [Eragrostis tef (Zucc.)Trotter].The objectives of this study were to clone and molecular characterization of GST gene in teff grass. We characterized GST1 from teff grass (EtGST1), it composed of a 645-bp open reading frame (ORF) that encoded 195 amino acid residue. Further, we transformed EtGST1 in E.coli BL21 (DE3) cells. This recombinant EtGST1 in E.coli BL21(DE3) induced at 37°C temperature. In addition, Growth of cells overexpressing EtGST1 rapidly increased in the presence of polyethylene glycol (5%), heat (46°C), NaCl (0.6%), and arsenic (1 mM) than that of cells harboring an empty vector. These results suggest that EtGST1 would be suitable candidate for improving tolerance in forages and/or grasses species against multiple abiotic stresses.
        30.
        2018.07 구독 인증기관·개인회원 무료
        This study reviews the SERVQUAL model theoretically and statistically in relation to the nonlinearity of the perceived service quality. Perceived service quality measurement based on the SERVQUAL model assumes that consumers evaluate service quality by comparing their perceptions with their expectations. However, previous studies adopt linear factor analysis to discuss the SERVQUAL model. The present study assumes that consumers evaluate the service quality with a standard to admit the difference between their expectations and perceptions, and that their perceived service quality follows a nonlinear response. A nonlinear SERVQUAL model based on a nonlinear factor analysis model is proposed to understand the characteristics. The proposed model employs a threshold specification that represents the space in which consumers admit their discrepancy. The study extends a nonlinear factor analysis model to a nonparametric model in order to examine the functional aspects that from the perceived service quality. A nonparametric SERVQUAL model is adopted without any assumptions of the functional form. The empirical studies on the retail sector shows that the nonlinear model performs better than the linear model, and that the nonparametric model estimates the nonlinear function for perceived service quality. The results from the proposed model in our study provide insights in a consumer’s perceived service quality recognized as nonlinear and asymmetric. We conclude that the functional form for perceived service quality should be considered when specifying the measurement model for SERVQUAL. In addition, we discuss future work for a nonlinear measurement model and a nonparametric factor analysis.
        31.
        2017.12 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to forecast the future Health Functional Food (HFF) market trends of Korea by studied about policies and market situation in Japan. The HFF is a food that is given an additional health function. In contrast with traditional foods, the HFF has unique characteristics in that it can be produced under the political regulations. The market size of the HFF was growing gradually due to the increased of an aging population and consumer need for high quality and diversified foods. The reason why the HFF market in Japan grew up earlier than other countries, Japan was the first country that institutionalized the HFF policies. Therefore, in this paper, by examining the policies and the market situation of Japan through literatures, we forecasted upcoming political and market situational changes of Korea’s HFF market. We noticed that consumers needs about the HFFs which diversified, confidently ensured safety and ingredients will increase. In this regard, the government will reorganize legislation in order to increase the confidence of the safety of HFFs. In addition, the market size of domestic HFFs which are produced by major food companies will grow.
        4,000원
        32.
        2017.10 구독 인증기관·개인회원 무료
        NRPS (non-ribosomal pepetide synthetase) plays an important role in the biosynthesis of secondary metabolites, which includes economically important compounds such as antibiotics, antitumor agents, immune-suppressants, siderophores, toxins, etc. In most cases, however, their functions and biosynthesizing pathways have been still remained riddles because of their cryptic expression and recalcitrant genetics. In our previous genome analyses of Cordyceps bassiana C101, we predicted the sequences of secondary metabolite biosynthesizing gene clusters, which contain non-ribosomal pepetide synthetases whose functions are already known such as beauvericin, bassianolide, bassiatin, tenellin, beauverolides, and oosporein. The authors focused on nrps6 that has not been functionally studied. The single-gene deletion and overexpression mutants were established via Agrobacterium-mediated transformations. PCR, quantitative real-time PCR, and southern blot analyses were carried out to confirm the correct single-gene integrated homologous recombination. In further study, comparative metabolic profiling between wild-type and mutant strains will be followed by their detailed chemical structure analysis through NMR spectroscopy.
        33.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the functions and structure of the system are complicated and elaborated, various types of structures are emerging to increase reliability in order to cope with a system requiring higher reliability. Among these, standby systems with standby components for each major component are mainly used in aircraft or power plants requiring high reliability. In this study, we consider a standby system with a multi-functional standby component in which one standby component simultaneously performs the functions of several major components. The structure of a parallel system with multifunctional standby components can also be seen in real aircraft hydraulic pump systems and is very efficient in terms of weight, space, and cost as compared to a basic standby system. All components of the system have complete operation, complete failure, only two states, and the system has multiple states depending on the state of the component. At this time, the multi-functional standby component is assumed to be in a non-operating standby state (Cold Standby) when the main component fails. In addition, the failure rate of each part follows the Weibull distribution which can be expressed as increasing type, constant type, and decreasing type according to the shape parameter. If the Weibull distribution is used, it can be applied to various environments in a realistic manner compared to the exponential distribution that can be reflected only when the failure rate is constant. In this paper, Markov chain analysis method is applied to evaluate the reliability of multi-functional multi-state standby system. In order to verify the validity of the reliability, a graph was generated by applying arbitrary shape parameters and scale parameter values through Excel. In order to analyze the effect of multi-functional multi-state standby system using Weibull distribution, we compared the reliability based on the most basic parallel system and the standby system.
        4,000원
        34.
        2017.04 구독 인증기관·개인회원 무료
        Insect cuticle/exoskeleton covering the entire external surface of the body is essential for protecting insects from various environmental stresses. Tyrosine metabolism plays a major role in not only the darkening of cuticle but also its hardening. In this work, we have focused on the functional analysis of nine genes involved in tyrosine-mediated cuticle tanning (pigmentation and sclerotization) pathway in Tenebrio molitor, which has a unique adult cuticle coloration, dark/black dorsal thorax and elytron, and reddish ventral thorax and abdomen. The temporal and spatial expression patterns of the genes were analyzed by real-time PCR, and RNA interference (RNAi) was performed to study the functional importance of these genes in cuticle coloration and/or hardening in T. molitor. This work was supported by NRFs (NRF-2015R1A2A2A01006614 and NRF-2015R1A6A3A04060323).
        35.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Riboswitches are structured RNA motifs that can directly bind specific metabolites. The binding of metabolites further regulates downstream metabolism eliminating the need for any regulatory proteins. We searched for novel bacterial vitamin B1 binding riboswitches in the metagenome of sun-dried saline soil. Soil microbial metagenomes were studied using NGS analysis. A total of approximately 50 Gb of the sequence data was obtained by Hi-seq and 454 GS FLX sequencing, and these sequences were subjected to riboswitch search. Hi-seq generated 614 contigs showing similarity to riboswitches, while 454-based sequencing generated 383 similar contigs. We matched whole metagenome contigs to local BLAST databases constructed using 91 previously known bacterial vitamin B1 thiamine pyrophosphate (TPP)-box motifs, and 11 SAM S-box motifs. Repetitive BLAST comparisons to local BLAST databases with nucleotide sequences from NGS identified 14 novel TPP-box motifs, and 7 S-box motifs respectively from the metagenome contigs. Further, RNA secondary structure analysis with public databases Rfam, and RibEx using these 21 riboswitch candidates revealed one contig, D8PYI to possess the most probable TPP-box structure. We constructed intragenic synthetic riboswitches to investigate whether the TPP-box motif region in D8PYI could harness gene expression in the presence of TPP. Construction of biosensors containing 100~400 bp fragments of D8PYI contigs, and in vivo imaging using the biosensors displayed TPP-specific changes in the expression of a green fluorescence protein reporter. In this regard, the adaptation of in silico riboswitch screening from environmental metagenomes could provide biosensors for detection of specific metabolites.
        4,000원
        36.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to find efficient and customized tools for delivering the benefit of health functional foods (HFFs). Delivery tools which could influence the impact of advertising were images, explanations of ingredients, diagrams of health benefit, patents, and comments from authority. Six advertisements were developed using these tools: “A”: relevant image + explanation of ingredients + scientific diagram of efficacy; “B”: relevant image + explanation of ingredients; “C”: relevant image; “D”: irrelevant image; “E”: irrelevant image + explanation of ingredient + patent; “F”: irrelevant image + explanation of ingredient + comments from authority. To analyze the consumer perceptions on HFFs and advertisement effects, 300 respondents were requested to answer a questionnaire comprising of the following questions: 5 questions of attitudes (necessity of HFFs, trust in HFFs, gathering information, watching advertisements and trust in advertisement claims) and 6 questions on the 6 developed advertisements (attention, understanding, sufficiency of information, sympathy, trust, and purchase). Scoring was done as per the 5 Likert scale. There was a higher proportion of females and the elderly, as compared to males and youngsters. The overall consumer attitudes were positive. Explanation of ingredients, scientific diagram of health benefit, patents and expert comments were helpful factors in increasing the advertisement evaluation by consumer, but the images were not. Advertisement evaluation of consumer did not differ with gender and age. However, differences were observed between some of the consumer attitudes (necessity of HFFs, trust in HFFs, gathering information and trust in advertisements claim) and advertisement evaluations (attention, understanding, sympathy and purchase). Our results indicate that for consumers utilizing the HFFs, advertisements with concrete tools such as diagrams, patent, and expert comments are more helpful. However, for consumers who do not have interest in HFFs, the scientific information was irrelevant. We believe that to maximize the effect of health information in advertisements, consumers should be segmented, and customized tools for each segment needs to be developed.
        4,600원
        37.
        2016.11 구독 인증기관·개인회원 무료
        본 연구에서는 술폰산기, 암모늄기를 가지는 폴리에테르에테르케톤계 고분자 소재에 대한 투과거동을 분석하기 위하여 분자 동력학 시뮬레이션을 이용하여 분석을 진행하였다. 술폰산기와 암모늄기의 함량을 조절하여 다양한 모델을 구 성하였으며, 도입된 관능기의 함량의 변화에 따른 하이드로니움, 히드록사이드 이온의 투과 거동에 대한 분석을 진행하였으며, 실제 실험 결과와 비교를 진행 하였다.
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