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        검색결과 152

        23.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To enhance the thermal properties of epoxy composites, expanded graphite (EG) was oxyfluorinated and embedded into epoxy resin as a reinforcement. The maximum thermal conductivity was obtained for epoxy composites with oxyfluorinated EG, representing a 62% increase compared to that of neat epoxy. Additionally, the glass transition temperature (Tg) and integral procedural decomposition temperature of epoxy composites with oxyfluorinated EG show the increase of 6% (4.4 °C) and 106% (264 °C), respectively, which indicated the improvement in thermal stability. These results can be attributed to the interfacial interaction between epoxy and oxyfluorinated EG, which formed strong interfacial interactions between the epoxy resin and EG due to the presence of oxygen- and fluorine-containing functional groups in oxyfluorinated EG.
        4,000원
        30.
        2018.04 구독 인증기관·개인회원 무료
        The change of phenolic compounds and radical scavenging activity of black soybean flours after germination and roasting treatment were evaluated as a part of the purpose of setting the quality of black soybean flours for each application. The moisture content of roasted black soybean flours decreased significantly according to roasting temperature and time, and the crude ash, protein, and fat contents increased. Water binding capacity of roasted black soybean flours without and with germination increased significantly according to roasting temperature and time, however water solubility index and swelling power decreased. The lightness of roasted black soybean flours was significantly decreased, and the redness and yellowness increased. The phenolic compounds and radical scavenging activity of roasted black soybean flours increase with increasing roasting temperature and time. The total polyphenol contents of roasted black soybean flours without and with germination were 5.43∼7.81 and 4.52∼6.17 mg GAE/g, and total flavonoid contents were 2.90∼3.50 and 2.34∼3.01 mg CE/g, respectively. DPPH radical scavenging activity of roasted black soybean flours without and with germination was 254.98∼415.05 and 171.95∼295.15 mg TE/100 g, and ABTS radical scavenging activity was 459.74∼596.37 and 422.95∼526.85 mg TE/100 g, respectively. As a result, it is necessary to set quality standards for each application considering the quality and antioxidant properties of roasted black soybean flours.
        31.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porcine spermatogonial stem cells (SSCs) prefer three-dimensional (3D) culture systems to 2D ones for the maintenance of self-renewal. Of the many 3D culture systems, agar-based hydrogels are candidates for supporting porcine SSC self-renewal, and there are various types of agar powder that can be used. In this study, we sought to identify an agar-based 3D hydrogel system that exhibited strong efficacy in the maintenance of porcine SSC self-renewal. First, 3D hydrogels with different mechanics were prepared with various concentrations of Bacto agar, lysogeny broth (LB) agar, and agarose powder, and the 3D hydrogel with the strongest alkaline phosphatase (AP) activity and greatest increase in colony size was identified for the different types of agar powder. Second, among the porcine SSCs cultured in the different 3D hydrogels, we analyzed the colony formation, morphology, and size; AP activity; and transcription and translation of porcine SSC-related genes, and these were compared to determine the optimal 3D hydrogel system for the maintenance of porcine SSC self-renewal. We found that 0.6% (w/v) Bacto agar-, 1% (w/v) LB agar-, and 0.2% (w/v) agarose-based 3D hydrogels showed the strongest maintenance of AP activity and the most pronounced increase in colony size in the culture of porcine SSCs. Moreover, among these hydrogels, the strongest transcription and translation of porcine SSC-related genes and largest colony size were detected in porcine SSCs cultured in the 0.2% (w/v) agarose-based 3D hydrogel, whereas there were no significant differences in colony formation and morphology. These results demonstrate that the 0.2% (w/v) agarose-based 3D hydrogel can be effectively used for the maintenance of porcine SSC self-renewal.
        4,000원
        32.
        2017.10 구독 인증기관·개인회원 무료
        Entomopathogenic fungi have been used to control pest as alternative to chemical pesticide. To kill the pest entomopathogenicfungi penetrate cuticle of pest, reach the hemocoel and utilize nutrient of host pest. Finally fungi kill the host by consumingthe host nutrient and physically damaging the tissues. But these process of fungi to control pest is needed so much timeand this point is a disadvantage for fungi. Therefore we studied other application method of fungi to control pest. Weconducted behavior test of beet armyworm to Isaria fumosoroseus which is high virulent against beet armyworm. Adultof the beet armyworm avoided oviposition at Chinese cabbage treated with I. fumosoroseus compare to control and otherhigh pathogenic isolate, Metarhizium anisopliae and this repellency of I. fumosoroseus lasted for 5days in greenhouse.Behavior of larvae to I. fumosoroseus also investigated with choice and non-choice test. Third to fifth instar larvae detectedand avoided fungi. Repellent behavior of larvae to fungi was more noticeable in younger larvae. This result may be usedto prevent the infestation of moth in crop production.
        33.
        2017.10 구독 인증기관·개인회원 무료
        The diamondback moth, Plutella xylostella is one of the world’s major pests. Economic cost to control this pest wasestimated between US$1.3 billion and US$2.3 billion based on management costs. Conservative estimate included yieldloss caused by 5% diamondback moth was estimated US$4 billion-US$5 billion. P. xylostella was managed by chemicalinsecticide such as organophosphates, carbamates and pyrethroids. But insecticide resistance which is caused by repeatedapplication makes it difficult to control this pest. For environmental friendly control of diamondback moth, entomopathogenicfungi could be used as alternative. We conducted bioassay to select high virulent isolate to larva of diamondback mothwith forty six entomopathogenic fungi which were isolated from soil samples by insect-bait method. As a result of bioassaytwelve isolates was selected as candidate. We investigated control efficacy of these twelve isolates with potted Chinesecabbage at laboratory and greenhouse.
        34.
        2017.10 구독 인증기관·개인회원 무료
        In recent 10 years, mushroom cultivation area and number of cultivators have decreased, but mushroom production tends to increase. This shows that mushroom cultivation is being transformed from log and bed cultivation to bottle cultivation using automated facilities with high productivity per unit area. The bottle cultivation is possible to mechanized and automated, which can save manpower, less damage to pests, can be cultivated throughout the year, and is uniform in quality and advantageous for mass production. However, the investment in production facilities and farm materials is very large compared to the production of logs and bed cultivars, which can lead to large losses in the case of failure to grow. Therefore, it is necessary for the farmers who want to start the bottle cultivation to make careful management decisions by carefully examining the investment cost, the operating cost, and the expected income that are put into the bottle cultivation system. This study was conducted to analyze the management performance of bottle cultivation in mushroom farm and use it as farming decision making data. As a result of analysis of the management performance through farmers' survey, it was found that such as cost of spawn, substrate materials, other material, employment effort, and fuels & electricity power cost accounted for a large proportion of the cost of bottle cultivation.
        36.
        2017.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungi have been used as important part of integrated pest management program to control aphid. In particular, Beauveria bassiana was distributed throughout the world including temperate and tropical area, various habitats from alpine soil, desert soil to running water and both insect and plant. Especially the fungus has also been isolated from the surface and the interior of plants and act as natural control agent. Viability of fungi on the plant surface may be influenced by temperature, humidity, sunlight and plant type as well as fungal isolate. Persistence of treated fungal control agent on phylloplane and control efficacy may differ from environmental conditions and isolates. In this study, we investigated the persistence of an B. bassiana which is developing as prototype wettable powder to control cotton aphid, and the residual efficacy of the prototype on cucumber under three different greenhouse conditions.
        37.
        2016.10 구독 인증기관·개인회원 무료
        Cotton aphid, Aphis gossypii Gloever is one of the major pests on a wide range of economically important crops in the world. The sustained use of chemical insecticides to control the aphid has led to the emergence of resistant strains to numerous used insecticides. As an alternative strategy entomopathogenic fungi have been used as part of integrated pest management program to control aphid, especially insecticide-resistance population. In particular, Beauveria bassiana-based commercial bio-insecticide has been used to reduce the pest population under greenhouse conditions in various countries. In this study, we investigated the control efficacy of a prototype of commercial mycopesticide using an B. bassiana (wettable powder) against cotton aphid on potted cucumber plant in greenhouse conditions.
        38.
        2016.10 구독 인증기관·개인회원 무료
        Various arthropods have directly and indirectly threatened human life by transmitting human pathogens such as malaria and Zika virus as well as by damaging crops such as direct feeding and transmission of plant pathogens. According to WHO, vector-borne diseases account for over 17% of all infectious diseases and there are over 1 million deaths from the diseases such as malaria, dengue, etc., globally. About 13% of total crop production is destroyed by agricultural pests during crop production and storage. To control medical or agricultural pests chemical pesticides have been used, but recently because of concerns about environmental pollution and human health the demands for eco-friendly control method are increasing. Insect pathogens are good alternative candidates instead of chemicals. Over 50 entomopathogens including viruses, bacteria, fungi and nematodes are now commercially used as microbial pesticides. Entomopathogenic fungi have also been evaluated as control agents for a diverse insect pests such as aphid, moth, thrip, whitefly, mosquitoes, tick, etc. We will discuss a development of microbial pesticides using, especially, entomopathogenic fungi to control noxious arthropods to agricultural crops and human.
        40.
        2016.04 구독 인증기관·개인회원 무료
        Beet armyworm, Spodoptera exigua, diamondback moth, Plutella xylostella and tobacco cutworm, Spodoptera litura are the three most serious pests of many economically important crops such as cruciferous crops, various vegetables and ornamental plants. Because these pests are known to be resistant to lots of chemical insecticides, integrated control using both or either entomophathogen and/or natural enemy is thought to be an attractive alternative for effective control. One of the obstacles using and expanding mycopesticide is narrow host ranges. At commercial farms, cultivating crops are seriously damaged by various Lepidopteran pests. Farmers want to use a microbial control agent which can control various host insects to reduce cost and labor. In previous study, we selected two entomopathogenic fungi, Metarhizium anisopliae and Paecilomyces fumosoroseus, which shown high virulence against beet armyworm. For wide use of the isolates in farm, we tested its host ranges, especially to diamondback moth and tobacco cutworm, which also are serious pest in Korea. The two isolates were shown a good control effect in leaf disc bioassy.
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