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        검색결과 302

        61.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리는 오리온 분자운 복합체의 북부 필라멘트(이하 NF)에 대하여 12CO (J=1-0) 분자선의 자료를 이용하여 은하 평면이 분자의 운동과 운동학에 미치는 영향을 연구하였다. 6 m 서울대학교 전파망원경(Seoul Radio Astronomy Observatory, SRAO)을 이용하여 2arcmin 공간분해능으로 은하면으로부터 먼 순서로 NF1, NF2, NF3 세 곳을 총 270시간 동안 관측된 자료를 사용하였다. 은하면과 OMC NF는 12CO (J=2-1) 경우 3% 밀도에서, 티끌의 경우 9% 밝기 수준에서 자기장을 따라 서로 연결되어 있었다. 12CO (J=1-0), 12CO (J=2-1), 성간 티끌 관측결과를 비교해본 결과, 세 경우 모두 NF3에서는 고루 분포했지만, NF1과 NF2에서는 비교적 밀도가 높은 특정 영역에서만 함께 나타났다. NF는 단일 구조를 보였으며, NF1에서는 부분 수축 운동을, NF2에서는 하단에서 회전 운동이 나타났고, NF3에서는 유일하게 명확히 자기장에 연관된 나선형 회전이 보였다. 위치-속도 분석 결과, 12CO (J=1-0)를 비롯한 물질들은 NF2와 NF3을 따라 은하면을 향하여 흐를 가능성이 있음을 확인할 수 있었다. 은하면을 향하여 물질이 흐르는 명백한 원인을 이번 연구결과에서 볼 수 없었지만 추후의 더 정교한 관측결과가 NF1과 NF2 상단부의 회전 운동을 확인 할 수 있겠다.
        4,600원
        64.
        2018.11 구독 인증기관·개인회원 무료
        Acute kidney injury (AKI) is a disorder that is manifested by a sudden decrease of renal function within several hours, and AKI remains a significant cause that can lead to increasing morbidity and mortality. Although AKI has been extensively studies in animal models, translating the results from animal studies into clinical use has not been successful due to various factors including basal etiology of kidney deficiency and comorbidities and the complexity of this pathology. As a golden parameter, measuring serum creatinine (SCr) and blood urea nitrogen (BUN) has been conventionally used for determining the renal function, however, these biomarkers has been regarded suboptimal to identify renal injuries in early stages. In this study, we attempted to screen other serum biomarkers in early AKI event using cynomolgus monkeys. Two male monkeys, aged 60 months, were subjected to ischemic injury by unilateral clamping of renal pedicles for forty five minutes and then subsequently reperfused; the unclamped kidney was regarded as non-injured controls. Compared with control kidneys, we have found that the concentration of several inflammatory proteins including MCP1, TGFα, GSTα, were higher in the renal vein of injured kidney compared with control side after 24 and 48 hours of AKI. However, changes of serum level of KIM-1, which is one of the most-widely studied marker in rodent studies, were not different after AKI. Our results provide an useful information while developing a novel marker in AKI.
        68.
        2018.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        TiO2-doped activated carbon fibers (ACFs) were successfully prepared as capacitive deionization (CDI) electrode materials by facile ultrasonication-assisted process. ACFs were treated with titanium isopropoxide (TTIP) and isopropyl alcohol solutions of different concentrations and then calcinated by ultrasonication without heat-treatment. The results show that a certain amount of anatase TiO2 was present on the ACF surface. The specific capacitance of the TiO2-doped ACF electrode was remarkably improved (by 93.8% at scan rate of 50 mV s–1) over that of the untreated ACF electrode, despite decreases in the specific surface area and total pore volume upon TiO2 doping. From the CDI experiments, the salt adsorption capacity and charge efficiency of the sample with TTIP percent concentration of 15% were found to considerably increase by 71.9 and 57.1%, respectively. These increases are attributed to the improved wettability of the electrode, which increases the number of surface active sites and facilitates salt ion diffusion in the ACF pores. Additionally, the Ti-OH groups of TiO2 act as electrosorption sites, which increases the electrosorption capacity.
        4,000원
        69.
        2018.07 구독 인증기관·개인회원 무료
        Certification labeling is a system which confirms the quality and appropriateness of pr oducts according to the standard set. It is usually evaluated by the third party to assure being reliability. Certification labeling can be used as one of the important sources of i nformation when consumers evaluate the products. Especially, certification labeling gi ves customers trust and confidence about products because the label can be the signali ng that the quality of the products is good. Although certification labeling influences p urchase decision making, many consumers do not trust the labels because of insufficie nt information of certification and distrust in the certifications. As consumers are becoming increasingly concerned about environment and wellbeing, manufacturers are turning a convention product into the production of a sustain able product. Sustainable certification can be environmental cues to evaluate a sustain able product based on the categorization inference. The aim of this research is the inte raction effect among sustainable cues on purchase intention. Consumers tend to perceive organic label of products as high-price. Thus, although they concern environment and well-being, they tend to purchase conventional products more than an organic product. In addition, an organic label can have a positive influence on perceived risk, and then perceived risk may affect purchase intention. However, the product with organic label including traceability may have a negative impact on perceived risk. Therefore, perceived risk can mediate the relationship between the interaction between organic label of products and traceability and purchase intention.
        70.
        2018.07 구독 인증기관·개인회원 무료
        While the portion of manufacturing in the global economy has steadily decreased for past a few decades, that of the service sector has steadily increased. Manufacturing industry needs to have a more competitive strategy in a hyper-competitive environment. More recently, the concept of servitization based ICT has emerged, which is the strategy to increase effectiveness and efficiency of products or services. Servitization is defined as “the offer of integrated packages of products, services, support, self-service, and knowledge to add value to the company’s core business,” according to Vandemerwe and Rada (1988). Servitization is to add the new service function to the existing equipment or the hardware-oriented product in the aspect of a product. Productization is to complement the limitations such as intangibility, inseparability, perishability, variability in the element of service. The two concepts have been regarded as distinctive concepts. In recent years, however, these two ideas have been integrated into a single idea of servitization. Good-dominant logic is based on the idea that the product provides customers with the value which they desire. In the vein, manufacturing products is a productive activity that creates value and increases the wealth of the nation. Therefore, the service may be perceived as being less productive. Service-dominant logic, however, is not a value-in-exchange between a company and a customer but a value-in-use which means “the evaluation of the service experience (i.e., the individual judgment of the total of all the functional and emotional experience outcomes).” In service-dominant logic, service is shown as the means of innovation through systematic methodological procedures including organization, people, and information technology by knowledge. As the concept of customers became more and more important, the product needs to be integrated with service. The research on servitization is expanding to various similar concepts such as product-service system, service science, servicing, and so on. Most of the previous research is focused on service type classification at the strategic level or service at the enterprise level. Moreover, most of them are exploratory research. Despite the need for a deeper understanding of customer needs, the research on servitization in the light on customers is sparse. The purpose of this study is as follows: First, define the concept of servitization experience and develop a tool to measure the servitization experience. Second, in order to verify the construct validity of the servitization experience, we examined whether the servitization experience affects the outcome variables such as value, commitment, retention intention. In order to develop a measurement tool for the servitization experience, the following process was carried out. First, concept and questionnaire items were derived from related studies. Second, field expert interviews were conducted to verify questionnaire items. Third, interviews with academic experts were conducted to verify whether they could be used as actual questionnaire items. Fourth, the questionnaires were collected and the collected data were analyzed to verify the reliability and validity of the measurement tools. The sample for empirical analysis was college students in their 20s and 30s, and a total of 150 responded to the questionnaire. First, reliability analysis and validity analysis were conducted to refine the questionnaire items. Structural equation modeling was performed using the refined Servitization experience questionnaire and a model was constructed using the servitization experience as an exogenous variable, with value, commitment, and retention intention as endogenous variables. As a result of the empirical analysis, it is confirmed that the sub - factors of servitization experience consist of four types of integrated product and service, customized servitization, relational servitization and playful servitization. Reliability and validity were satisfied. Through this study, we can contribute to the empirical study of servitization by developing a scale to measure servitization experience. Thus, the purposes of this study are to identify the servitization experience factors that companies should consider in marketing strategy, to grasp the relationship between servitization and customer retention.
        71.
        2018.07 구독 인증기관·개인회원 무료
        The frequent accidents of workplace in Korea make workers consider their more than before. This research aims to investigate the effect of safety climate on safety behavio rs and job satisfaction based on the mediational model to drive proactive and complia nce safety behaviors. The conceptual model of safety behaviors focuses on company’s safety behaviors perceived by workers. The model explains how organizational safety climate affect safety outcomes, compliance safety behaviors and proactive safety behaviors, through the mechanism of situational related factors and personal related factors. In this study, it is proposed that safety knowledge of workers and communication styles moderate the effect of safety climate on compliance safety behaviors and proactive safety behaviors. The data were collected by Korean workers using survey and analyzed by AMOS 22.0.
        72.
        2018.05 구독 인증기관·개인회원 무료
        The ride quality (i.e. smoothness) is a key factor for evaluating the construction quality of expressway asphalt pavement. Conventionally, three paving devices are widely used to control the surface layer thickness: leveling sensor (i.e. LS), short-range-surfacing-contact-ski (i.e. SSCS) and long-range-surfacing-contact-ski (i.e. LSCS). However, each of these levelling tools presents one major drawback. In the case of LS, if the original sub-layer evenness is poor, the final asphalt pavement surface and its smoothness will be negatively affected. The SSCS cannot assure satisfactory smoothness when relatively long paving section (in the order of 10 km) are paved. While the LSCS would reduce the drawback of the SSCS, its weight on the one hand and its length on the other discourage its use in the paving site especially for curved sections. In this paper, a next generation pavement smoothness leveling equipment, known as non-contact-digital-ski (i.e. NCDS) was implemented, evaluated and compared to the conventional equipment leveling device. The international Roughness Index (IRI m/km) was measured on sections paved with and without NCDS and the results visually and statistically compared. In addition, for the same sections, the modulus of the pavement layers was computed and compared by means of Falling Weight Deflectometer (i.e. FWD). It was observed that when NCDS is used for asphalt pavement overlay of existing concrete pavement, significant improvement in IRI (i.e. IRI<1.0m/km) and consistently uniform elastic modulus could be achieved compared to the conventional levelling and paving method.
        74.
        2018.04 구독 인증기관·개인회원 무료
        RNA interference (RNAi) has been considered as an alternative strategy to control agricultural pest whereby double-stranded RNA triggers a potent and specific inhibition of its homologous mRNA. Since small dsRNAs are required for various RNAi applications, there is a need for cost-effective methods for producing large quantities of high-quality dsRNA. In this study, Bacillus thuringiensis (Bt) based dsRNA production platform was established under control of sporulation-dependent promoter and vp1 gene of Sacbrood virus (SBV) was introduced. The dsRNA against vp1 gene produced from the Bt suppressed the replication of SBV. In addition, the dsRNA was assembled into inulin coated-nanoparticle to increase stability of dsRNA in environment.
        75.
        2018.04 구독 인증기관·개인회원 무료
        Streptomyces has been reported to produce various secondary metabolites which have the potential to become environmentally safe insecticides. In this study, 1,274 streptomyces culture filtrates were screened for their JHAN activity in order to identify novel insecticidal compounds. 34 isolates with high levels of JHAN activity were selected, and their insecticidal activities were tested against Plutella xylostella larvae. Among them, IMBL-263 which was revealed to be Streptomyces anulatus by 16s rRNA sequencing showed the highest insecticidal activity. Also, systemic activities of secondary metabolites extracted from the S. anulatus on plant, Brassica napus, were investigated. These results suggested that secondary metabolites from the S. anulatus might be useful for development of novel environmentally benign insecticides.
        76.
        2018.04 구독 인증기관·개인회원 무료
        The development of entomopathogenic fungi has received increasing interest as part of integrated pest management strategies as biocontrol agents. It is reasonable to assume that entomopathogenic fungi might produce secondary metabolites modulating juvenile hormone for their survival against defense mechanisms of host insects. In this study, acetone extracts of 189 entomopathogenic fungi cultured on unpolished rice medium were screened for their juvenile hormone antagonist (JHAN) activities using the yeast-two hybrid system. Among 14 extracts showing JHAN activities, extract of the F-145 showed high level of insecticidal activities against both Plutella xylostella and Aedes albopictus. This isolate was identified as Lecanicillium attenuatum. These results suggested that the Lecanicillium attenuatum could be useful for development of eco-friendly insecticides.
        77.
        2018.04 구독 인증기관·개인회원 무료
        Beet armyworm, Spodoptera exigua, is known to be hard-to-kill pest by having high resistance to insecticides and its control is intensely dependent on fewer insecticides. In this study, the ethyl acetate extract of Streptomyces sp. was evaluated to find novel insecticidal agents against S. exigua. In order to determine the identity of insecticidal compounds, the crude ethyl acetate extract was fractionated based on the TLC profiling and bioassay-guided monitoring. These results indicated that the non-polar fraction have high level of insecticidal activity against second instars of S. exigua. These findings suggested that secondary metabolites produced by Streptomyces sp. could be considerable potential resources as novel insecticidal formulation candidates.
        78.
        2018.04 구독 인증기관·개인회원 무료
        Insect growth regulators (IGRs) are insecticides that disrupt the normal development of target insects. Among the IGR insecticides, juvenile hormone (JH)-related IGRs are of particular interest because they stimulate or interfere with the formation of JH receptor complex. In the precious studies, novel JH-related IGRs with JH agonist (JHA) and antagonist (JHAN) activity were identified by using yeast two-hybrid system transformed with the Aedes aegypti JH receptor complex. In this study, the transcriptomic responses of Aedes albopictus were investigated upon JHA and JHAN, respectively. These results will provide important information about understanding of impact of JH-related IGRs in transcription level.
        79.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To elucidate the effect of cellular phone electromagnetic wave (EMW) exposure on the developing cerebellar cortex of neonatal Sprague-Dawley rats, animals were exposed to cellular phone electromagnetic waves for 1 hr per day for 3 weeks. At the end of the experimental period, animals were sacrificed by cardiac perfusion, after which histological samples were prepared and observed microscopically. In the EMW exposure group, external granule cells were remained partially in the external granular layer without migrating into the internal granular layer. In addition, dark stained shrunken Purkinje cells with pyknotic nuclei increased and the outline of cells became irregular and showed degenerative signs, such as mitochondrial swelling and disrupted cristae. Moreover, the cisternae of rough endoplasmic reticula and Golgi complex were severely swollen. Bergmann glial cells adjacent to the dark stained Purkinje cells were swollen and cytoplasmic organelles were scant. Dark stained shrunken granule cells were also observed and the outline of cells was irregular. The results of the present study suggest that cellular phone EMW exposure to neonatal Sprague-Dawley rats leads to a partial delay of early migration of cerebellar cortical cells and degenerative changes in Purkinje cells, Bergmann glial cells and granule cells.
        4,000원
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