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        검색결과 167

        61.
        2018.10 구독 인증기관·개인회원 무료
        This study investigated the fumigant activity of phosphine (PH3) on 2 kinds of mealybug (Pseudococcus longispinus and P. orchidicola (Hemiptera: Pseudococcidae)) adults and nymphs. All of the two mealybugs adults showed higher LCT99 values than nymphs, and P. longispinus showed higher tolerance than P. orchidicola in a 12 L desiccator. The absorption of phosphine on 13 nursery plants showed 12.2~41.5% difference depending on the plant. All of the mealybugs treated with phosphine 2 mg/L in 0.5 m3 fumigation chamber for 4 h showed 100% fumigant activity, except P. longispinus adult (approximately 90% at bottom part). However, when the exposure time was increased to 24 h, all of them showed 100% mortality. In the treatment of 10 m3 container, the 24 h treatment of phosphine showed 100% mortality to P. longispinus and P. orchidicola adults and nymphs. In all the experiments, no phytotoxicity of phosphine observed on 13 plants until 1 month after treatment.
        62.
        2018.10 구독 인증기관·개인회원 무료
        Acaricidal activities of 63 commecial pesticides against the longhorned tick, H. logicornis were investigated. Twenty-two pesticides (4 cabamates, 5 organophophates, 9 pyrethroids, 1 octopamine receptor agonists, 1 diamides, and 1 unknown) against adults H. logicornis showed >80% mortalities after 72 h of treatment. The residual effect of 22 pesticides was investigated at 1, 2, 3, 7, and 10 day intervals on grass for H. logicornis adults and nymphs. Eight and twenty pesticides in H. logicornis adults and nymphs showed >80% acaricidal activity at 3 days after the treatment, respectively. 7 days after the treatment, H. logicornis adults showed <60% acaricidal activity in all pesticides, but 7 pesticides (benfuracarb, gamma cyhalothrin, cypermethrin, lammda cyhalothrin, fenvalerate, cyantraniliprole, fluxametamide) showed >80% acaricidal activity in nymphs. all pesticides exhibited <60% acaricidal activity after 10 days of treatment both adults and mymphs, except benfuracarb showed 96.7% mortality in H. logicornis nymph.
        63.
        2018.10 구독 인증기관·개인회원 무료
        A combination using phosphine (PH3) and ethyl formate (EF) was performed to compensate for the disadventages (long exposure time and phytotoxicity) of a single substance. P. longisipinus was more susceptible to mixed phosphine and ethyl formate than P. orchidicola in 12 L dessicator. Mortality of mixed treatment was higher than aggregated mortalities that treated individually, so it indicated to have a synergic effect on each other. Ethyl formate was showed higher adsorption rate than phosphine on imported nursery plants and showed differences depending on the plant. P. longispinus and P. orchidicola was showed 100% mortality when phosphine and ethyl formate was treated as 1 g/m3 and 30 g/m3 for 4 hour in 0.5 m3 fumigation chamber and in 10 m3 container. Phytotoxicity was evaluated to mixture of phosphine and ethyl formate at 1 month after treatment.
        64.
        2018.05 구독 인증기관·개인회원 무료
        Most of the expressway concrete pavements in Korea have been constructed with jointed plain concrete pavements. However, the premature failure of joints occurred on some routes and it is considered to be related to the durability of concrete. Korea Expressway Corporation has been continuously devoting efforts to increase the durability of concrete, and recent research has shown that premature failure of jointed plain concrete pavement constructed recently has decreased. The durability of pavement concrete is determined by internal and external factors. Currently, the durability of pavements concrete is controlled by controlling the quantity and the spacing factor of internal air. In this study, the feasibility of evaluating concrete durability through absorption performance tests was examined. The absorption performance was evaluated by applying ASTM C 1585 and modified NBN B 15-215 in Belgium and applied to the pavement concrete mixed in the laboratory or collected on site. Each test is a method to evaluate water absorption performance, but ASTM evaluates the absorption performance through the upper surface and NBN evaluates the absorption performance through the entire surface of specimens. In this study, the absorption performance of the pavement concrete measured according to the test method was compared and the advantages and disadvantages of the performance evaluation method were examined through comparison of test results and procedures. As a result of the absorption performance test on the cores collected at the site, the amount of water absorption in the region where the few premature failure was occurred was relatively small. Also, the specimen of lower water cement ratio absorbed the smaller amount of water. And the small amount of aggregate at the surface showed tendency of the large absorption of the water. The amount of absorption due to the increment of air content showed a moderate increment but it was relatively small. This study has confirmed the possibility of estimating the durability through the evaluation of the absorption performance of concrete. However, further study is needed to extend the results obtained from the test method to the evaluation criteria of pavement concrete.
        65.
        2018.05 구독 인증기관·개인회원 무료
        Roller Compacted Concrete Pavement (RCCP) is placed by roller compaction of a mixture of less cement and unit water content and more aggregates and provides excellent early strength development with the help of interlocking of aggregates and hydration. The unit cement content of RCC pavements accounts for 85% of conventional pavements, with low drying shrinkage. As low drying shrinkage leads to smaller crack widths than ordinary concrete, RCC pavements can help elevate reflecting crack resistance if applied to a base layer of a composite pavement system. In a composite pavement with an asphalt surface laid over a concrete base, pavement temperature change is important in predicting pavement performance. As movement of the lower concrete layer is determined by temperature depending on pavement depth, temperature data of the pavement structure serves as an important parameter to prevent and control reflecting crack. Among the causes of reflecting crack, horizontal behavior of the lower concrete layer and curling-caused vertical behavior of joints/cracks are considered closely related to temperature change characteristics of the lower concrete course (Baek, 2010). Previous studies at home and abroad about reflecting crack have focused on pavement behavior depending on daily and yearly in-service temperature changes of a composite pavement (Manuel, 2005). Until now, however, studies have not been conducted on initial temperature characteristics of concrete in composite pavements where asphalt surface is placed over an RCC base. Annual temperature changes of in-service concrete pavements go up to 60 ℃, and those of asphalt overlays become around the twice at 110 ℃. This study evaluated initial crack behavior of composite pavement by investigating pavement temperature by depth of an RCC base and analyzing joint movement depending on change to temperatures of continuously jointed pavements. Findings from the study suggest that in composite pavements and asphalt overlays, time of laying asphalt has an important impact on crack behavior and reflecting crack.
        66.
        2018.04 구독 인증기관·개인회원 무료
        The present study evaluated the susceptibility of field populations of Plutella xylostella and Spodoptera exigua larvae to four diamide insecticides—chlorantraniliprole, cyantraniliprole, cyclaniliprole, and flubendiamide. All the four diamide insecticides induced 100% mortality in the populations from Seongju (SJ) and Geochang (GC) when treated at a concentration recommended for P. xylostella. However, a very low insecticidal activity was observed in the population from Pyeongchang (PC) with 42.3% 3 d after treatment with chlorantraniliprole. Further, the populations of S. exigua from Cheongju (CJ), Jindo (JD), and Yeonggwang (YG) were not completely controlled by the 4 diamide insecticides. A comparison of susceptibility of S. exigua larvae to chlorantraniliprole between 2014 and 2017 showed that chlorantraniliprole induced 100% mortality in all populations in 2014, whereas a very low insecticidal activity was observed among the populations in 2017. This study can serve as a basis to control pests effectively using diamide insecticides.
        76.
        2017.10 구독 인증기관·개인회원 무료
        Although the grasshopper Oxya chinensis sinuosa has long been used as a food in Korea, there is little data on itsfunctional effects. Thus we prepared and analyzed total RNA from the whole body of adult Escherichia coli non-immunizedand immunized Oxya chinensis sinuosa strains. Using an Illumina Hiseq sequencer, we generated a total of 66,555 pooledtranscriptome and singletons with and without Escherichia coli immunization, respectively. Then, we performed in silicoanalysis of the Oxya chinensis sinuosa transcriptome, using bioinformatics tools for screening putative antimicrobial peptides(AMPs) and 38 AMPs were finally selected and tested their antimicrobial activity of Gram positive, Gram negative bacteriaand antifungal activity with radial diffusion assay. As a result, 5 out of 38 AMPs showed the highest antimicrobial activityand antifungal activity against microbes and it also evidenced with no hemolytic activity.
        77.
        2017.10 구독 인증기관·개인회원 무료
        This study was carried out to investigate insect community structure from different habitats in Baengnyeong island.We performed day and night collection at two different habitats (mountain, rural area) of Baengnyeong island from Mayto September in 2015. A total of 2,879 individuals of 404 species, 81 families belonging to 10 orders were collectedand identified. A dominant species was Idisia ornata Pascoe (Tenebrionidae) despite a very low percentage (6.04%) ofthe species among the catches. Results of independent t-test showed a significant high (p<0.001) of species richness onmountain. Also, seasonal results of ANOVA (Analysis of variance) were significantly influential with species abundanceand species richness. The result of NMDS analysis showed that the community structure of the insects from the mountainis different with rural area.
        78.
        2017.07 구독 인증기관·개인회원 무료
        Social media play a role in the value that sneakerheads, individuals who collect, wear, and trade sneakers with extraordinary effort and resources, place on specific brands and models of sneakers. In-depth interviews with 25 sneakerheads, recruited through sneakerhead online communities and snow-ball sampling, were conducted to explore how social media contribute to emotional and monetary value creation of sneakers, as well as how social media is used across the Inventory Ownership Cycle (IOC) which includes pre-acquisition, acquisition, physical possession, and disposal of sneakers (Boyd & Mcconocha, 1996). Finding shows that during the pre-acquisition stage, emotional and monetary value is constructed when brands post images of celebrities wearing new models on various social media sites. Hype initially created by the brand is perpetuated by posts and conversations among sneakersheads. Perceived higher levels of hype lead one to believe demand surpasses supply, and therefore, monetary values of specific models increase. Through social media, consumers research and gauge the value not only of soon to be released sneakers, but also previously released sneakers only available on the resale market. During the acquisition stage, the online environment has become increasingly important. To avoid issues associated with selling high-demand/low-supply sneakers in- store, such as violent incidents and dishonest employees, many retailers have shifted sales of such product to online formats (Dunne, 2014). Social media serves as a platform for sneakerheads to learn about dates and locations of new releases and to locate resellers from whom they can purchase previously released sneakers. During the physical possession stage, sneakerheads engage with community members via social media; they show off their sneaker collections, as well as to obtain and share information regarding sneaker customization and maintenance to preserve aesthetics and value. It is through the engagement with fellow sneakerheads and the sneakers within their personal collections that emotional value can be further constructed. During the disposal stage, social media is used by resellers to determine monetary value, identify and communicate with potential buyers across the nation, and complete resale transactions. In summary, this research demonstrates how sneakerheads use social media throughout the IOC, as well as the role social media plays in the construction and identification of sneaker value.
        80.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Multiple interferon tau (IFNT) genes exist in bovine. An antiluteolytic substance secreted by the bovine conceptus and primarily responsible for maternal recognition of pregnancy is bovine trophoblast protein 1 (bIFNT1), a new type I interferon tau (IFNT) genes. The objectives of this research were to investigate whether multiple, distinct gene encode bIFNT1 and other type I bIFNT gene in the bovine genome and to examine expression of bIFNT1 and other bIFNTc1 mRNAs during conceptus development. These transcrips could be regulated through caudalrelatedhomeobox-2 (CDX2) and ETS2 and/or AP1 (JUN) expression, a transcription factor implicated in the control of cell differentiation in the trophectoderm. The presence of mRNAs encoded by bIFNT1 and type I bIFNTc1 genes were examined quantitatively via reverse transcription-polymerase chain reaction (RT-PCR) analysis of total cellular RNA (tcRNA) extracted from on day 17, 20 and 22 bovine conceptuses. The expression level of bIFNT1 was higher on day 17 transcripts were gradually weakly detectable on day 20 and 22. However, the other bIFNTc1 gene examined transcripts was highly expressed on day 20 and transcripts were weakly detectable on day 17 and 22 bovine conceptuses. Furthermore, human choriocarcinoma JEG3 was co-transfected with an -1kb-bIFNT1/c1-Luc constructs and several transcription factor expression plasmids. Compared to each -1kb-bIFNT1/c1-Luc increased when this constructs were co-transfected with, ETS2, AP1(JUN), CREBBP and/or CDX2. Also, bIFNTc1 gene was had very effect on activity by alone ETS2, and AP1 (JUN) expression factors in choriocarcinoma JEG3 cell. However, bIFNT1 gene expression of the upstream region was not identified. We demonstrated that the activities of bIFN genes are regulated by differential, tissue-specific and developmental competence during pregnancy.
        4,500원
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