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        검색결과 23

        2.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerous studies have reported that good adhesion and fluorination of carbon materials in a fluoropolymer matrix enhance their electrical and mechanical properties. However, a composite reinforced with oxyfluorinated graphite has not been reported for improving mechanical properties. This paper discusses the fabrication of conductive fluorinated ethylene–propylene (FEP)/oxyfluorinated graphite (f-graphite) composite bipolar plates (BPs) via compression molding. To investigate the effects of fluorinating graphite, graphite with a large particle size of 500 μm was mixed with FEP powder with a small particle size of 8 μm through ball milling. The FEP/graphite composites exhibited high anisotropic electrical conductivity with the in-plane conductivity much higher than the through-plane conductivity because of the planar orientation of the graphite sheets. Therefore, the mechanical properties of the composites such as flexural strength tended to deteriorate with increasing graphite content. In particular, the FEP/f-graphite composites exhibited excellent flexural strength of 12 MPa, much higher than that of FEP/graphite composites at 9 MPa with a graphite content of 80 wt%. The interfacial interaction between FEP and f-graphite led to improved physical compatibilization, which contributed to enhance the mechanical properties of these composites. Our results are a step toward developing BPs for use in high-temperature fuel cells and heat-sink components.
        4,000원
        9.
        2019.04 구독 인증기관·개인회원 무료
        The baculovirus expression system is a very useful tool widely used for expression of foreign proteins. To use the baculovirus expression system, a recombinant baculovirus must be prepared. The development of the Bac to Bac system has reduced the time and effort required to produce recombinant baculovirus. But, it will take at least two weeks. Further, it takes more time to measure the activity of recombinant baculovirus. In order to overcome this problem, a virus inducible expression system is being studied recently. Although baculovirus is able to rapidly express foreign proteins, it still has a low expression level. Thus, in this study, we aimed to construct a novel baculovirus inducible expression vector that not only shortens the production time of protein but also can express at a high level. The novel baculovirus inducible expression vector has been evaluated using EGFP and is expected to be a very useful tool for production of various proteins.
        10.
        2018.10 구독 인증기관·개인회원 무료
        Virus-like particles (VLPs) are similar to pathogenic viruses, but because they have no nucleic acid, they have excellent safety and immunogenicity and are used as a good vaccine material. However, in the selection of various structural proteins of pathogenic viruses to form VLPs, all expression systems consume a lot of time in common. Among them, the baculovirus expression system causes additional time consumption to construct the recombinant baculovirus. Therefore, there is a need for a system that can rapidly determine the structural proteins required for effective VLP production. This study aims at solving this problem by constructing a BmNPV inducible expression platform through the construction of vectors induced by BmNPV. The platform was evaluated for overexpression using EGFP. We also confirmed the formation of virus-like particles through overexpression of canine parvovirus structural proteins.
        11.
        2017.07 구독 인증기관·개인회원 무료
        Individual safety is a fundamental concern. People generally try to avoid danger or mishaps in the workplace, and to consider safety as a primary condition for satisfactory employment and agreeable shopping experiences. Organizations can assure that workers, clients, the public, and the environment perceive that they are in safe environments by providing highly secure services. Secure working environments and safety-focused human resource environments are essential antecedents to safe performance and outcomes. Dangerous workplace environments cause employees to feel stress and anxiety. Thus their performance decreases and accidents and injuries increase. Workplace safety is the most important factor influencing service and performance, especially for allowing frontline salespersons to focus on providing customer satisfaction. In this study of workplace safety, we apply the service quality dimension to examine its relationship with employee perceptions of job satisfaction and their related job performance. We discuss theoretical and practical implications based on the results.
        12.
        2015.10 구독 인증기관·개인회원 무료
        Porcine epidemic diarrhea virus (PEDV) causes acute diarrhea and dehydration in pigs with high mortality. PEDV is belong to Coronavirus, enveloped, single-stranded, positive-sense RNA virus. PEDV particles were composed of four structure proteins such as a glycosylated peplomer (spike, S) protein, envelope (E), glycosylated membrane (M) protein, and unglycosylated RNA-binding nucleocapsid (N) protein. Many of previous studies talk about this four structure proteins have a great potential to diagnosis and prevent PEDV. In this study we investigated expression of these structure proteins using the bacterial and baculovirus expression system. In bacterial expression system, our results showed that structure proteins fused polyhedrin and intein gene were expressed higher than non-fusion structure proteins. The expressed fusion proteins were used to immune mice for generating a polyclonal antibodies. In baculovirus expression system, co-infection of insect cells with these four recombinant baculoviruses led to self-assembly of virus-like particles as demonstrated by Transmission electron microscopy. They were confirmed by western blot analysis using pre-made polyclonal antibodies. Finding in this study may provide important information for vaccine and diagnostic development.
        13.
        2015.10 구독 인증기관·개인회원 무료
        Insects are among the most diverse groups of animals on the planet, representing more than half of all known living organisms. These insects are found in nearly every environment. Although humans regard certain insects as pests and attempt to control them using insecticides, most insects perform complex ecological functions, and provide either direct or indirect economic benefits to humans. Recently, the importance of insects used as food sources or as pets has increased in many countries, including Korea. In addition, several insects have a strong influence on people's emotion. Insect-mediated mental healthcare program is designed to help people who have disorders with physical, behavior and development. Children who have mental disorder, the experimental group that was provided with an insect-mediated mental healthcare program over a total of 8 sections, one section per week, 60 minutes per section, followed by pre-test and post-test. They responded to therapeutic effect after the completion of the program. Further research on the basis of this study is expected to help children with emotional therapy in other areas.
        14.
        2015.10 구독 인증기관·개인회원 무료
        The population of managed honey bees has been dramatically declining the recent past in worldwide. The one of most common disease of bees is nosemosis, the nosemosis is caused by microsporidia in the genus Nosema. Nosema apis and N. ceranae have been described as honeybee pathogens. These microsporidia are highly evoloved fungi with an obligately intracellular parasitic lifstyle. The disease causes significant detriment to honey production and results in economic losses. In our knowledge, Fumagillin is the only antibiotic approved for control of nosemosis in honey bees, however this antibiotic may have unintended effects on the honey bee host, ultimately contributing to increased prevalence and pathogenicity of Nosema. Therefore, we screened anti-Nosema substances from entomopathogenic fungal culture filtrates using in vitro polar tube germination assay. These fungal metabolites are employed as antibiotic agents. As results, Total 3 samples (23% of 13 total samples) showing the germinating inhibition against N. ceranae. This screening method may be useful for the detection of anti-Nosema substances from various samples and selected samples in this study may be a good feature to be used in the development of a new biocontrol method of nosemosis.
        15.
        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.
        16.
        2014.07 구독 인증기관·개인회원 무료
        Play is essential to life because it gives children joy, helps them grow, and provides important educational benefits. But in the past three to four decades, Korea has become rapidly urbanized and industrialized, so that the country has overlooked the educational importance of childhood play. Moreover, the parental mindset has turned from valuing the social environments found in natural playgrounds to supporting result-oriented education and competition. Recently, however, play is becoming recognized again for its educational benefits. Those needs have opened new business opportunities in the playground business. One of those new businesses is Kids Café, which provides indoor playgrounds for preschool-age children and café facilities for parents. Korea has no legal guidelines regarding formation of these businesses, and no detailed studies have been conducted to study customers’ needs. For businesses to be competitive in the future, they must know how they can compete by enhancing customer benefits. This study is intended to develop a marketing strategy for Kids Café by analyzing its competitiveness based on needs of children and their parents. We find that Kids Café has several main advantages in comparison with other playgrounds. Kids Café allows parents and children to enjoy themselves independently. Parents especially enjoy being easily able to see and monitor their children, and can take part in the program if they wish. The program does not require regular attendance as do paid classes and cultural centers; parents can bring their children when they have available time. Finally, children and parents can enjoy their leisure time both independently and collaboratively. Price, safety, play diversity, and convenient rest opportunities for parents determine whether parents will return to Kids Café. For sustainable growth, Kids Café must develop a customized and optimized marketing strategy according to customer type and needs.
        18.
        2013.07 서비스 종료(열람 제한)
        The aim of this study was to select the abiotic tolerant sorghum mutants using chlorophyll a transient OJIP analysis of PSⅠ and PSⅡ so called Kautsky’s effect within 1 second. It was clearly identified that wwt-and drought tolerant sorghum mutants could be classified by wet factor index(WFI). On the basis of WFI, wet tolerant sorghum matants were classified as follows; Ⅰ group, MUT534 bmr/new, MUT525 bmr; Ⅱ group, M2P1207 bmr, 25M2-0404 bmr, MUT371 bmr24, unknown bmr22, 10M2-0775 bmr, MUT135 bmr23; Ⅲ group, M2P0411 bmr, MUT641 bmr, M2P1064 bmr36, MUT855 bmr, 25M2-0137 bmr/new, MUT436 bmr, M2P0929 bmr, 25M2-0026 bmr, 10M2-0387 bmr, 25M2-0173 bmr/new; Ⅳ group, 25M2-0698 bmr. In conclusion, for the selection of wet tolerance, four photochemical parameters such as Electron transport flux until PSI acceptors per PSII(RE1o/RC), Performance index for energy conservation from photons absorbed by PSII antenna, until the reduction of PSI acceptors(PI_total ABS), Driving force on absorption basis(DF_total ABS) and Electron transport flux from QA to QB per PSII(ETo/RC) were important photochemical parameters deduced from maximum quantum yield and electron transport efficiency.
        19.
        2012.06 KCI 등재 서비스 종료(열람 제한)
        광나무(L. lucidum)는 ursolic acid와 oleanolic acid를 다량 포함하고 있다. 본 연구에서는 광나무 열매, 줄기, 잎 세 부위 추출물의 항주름 효능을 평가하였다. 광나무 추출물은 human skin fibroblasts에서 독성이 없을 뿐만 아니라 MMP-1과 MMP-2의 발현을 감소시키고 COL1A1의 발현을 증가시켰다. 이들 추출물은 모두 농도 의존적으로 COL1A1의 발현을 증가시켰으며 MMP-1과 MMP-2의 발현을 감소시켰다. 광나무 세 부위 추출물 가운데, 열매 부위에 가장 많은 양의 ursolic acid 와 oleanolic acid가 함유되어 있었으며 가장 강한 COL1A1 upregulating 효과와 MMP-1과 MMP-2 downregulating 효과를 나타냈다. 이처럼 항주름 효능을 보이는 광나무 열매 추출물은 기능성 화장품 소재로 개발될 수 있는 가능성이 있다.
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