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        검색결과 247

        103.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We demonstrated an effective way of preparing melt spinnable mesophase pitches via catalytic hydrogenation of petroleum residue (fluidized catalytic cracking-decant oil) and their subsequent thermal soaking. The mesophase pitches thus obtained were analyzed in terms of their viscosity, elemental composition, solubility, molecular weight, softening point and optical texture. We found that zeolite-induced catalytic hydrogenation under high hydrogen pressure contributed to a large variation in the properties of the pitches. As the hydrogen pressure increased, the C/H ratio decreased, and the solubility in n-hexane increased. The mesophase pitch with entirely anisotropic domains of flow texture exhibited good meltspinnability. The mesophase carbon fibers obtained from the catalytically hydrogenated petroleum residue showed moderate mechanical properties.
        4,000원
        104.
        2017.10 구독 인증기관·개인회원 무료
        β-glucan is a safe and highly potent biological response modifier that nutritionally activates the immune response through the Macrophage, Dendritic and additional immune cells to yield various therapeutic effects. Shiitake mushrooms (Lentinula edodes) contanining β-glucans may be beneficial for human health; they have been used in the treatment of cancer, hypertension, and high cholesterol levels. The effect of different substrates and various developmental stages (mycelium growth, primordium appearance, and fruiting-body formation) on β-glucan production in the edible mushroom L. edodes was studied. The cap of the mature mushroom showed the highest β-glucan activity, and β-glucan activity seemed to be influenced somewhat by some well-known inducers or sawdust. In this study, we utilized five strains (JMI 10022, 10036, 10077, 10079, 10080) of L. edodes regardless of origin and growth conditions. This experiment showed that the expression of β-glucan was induced by glucose bond, and increased with the growing of L. edodes. Quantitatively, reverse transcription PCR utilized pairs of primers specific for β-glucan gene expression shows that expressed genes were most commonly indentified during the process of fruiting-body formation. We suggest that the results will provide valuable information to assist L. edodes industry.
        105.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanopowders provide better details for micro features and surface finish in powder injection molding processes. However, the small size of such powders induces processing challenges, such as low solid loading, high feedstock viscosity, difficulty in debinding, and distinctive sintering behavior. Therefore, the optimization of process conditions for nanopowder injection molding is essential, and it should be carefully performed. In this study, the powder injection molding process for Fe nanopowder has been optimized. The feedstock has been formulated using commercially available Fe nanopowder and a wax-based binder system. The optimal solid loading has been determined from the critical solid loading, measured by a torque rheometer. The homogeneously mixed feedstock is injected as a cylindrical green body, and solvent and thermal debinding conditions are determined by observing the weight change of the sample. The influence of the sintering temperature and holding time on the density has also been investigated. Thereafter, the Vickers hardness and grain size of the sintered samples have been measured to optimize the sintering conditions.
        4,000원
        106.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The ability of plants to endure environmental stress factors, which are going to be more severe due to global warming, is important especially for forest plants. Because obtain trait of resistance to temperature using conventional breeding for woody plants is a time consuming way. In this study, chloroplast-localized OsHSP26 gene was overexpressed in Populus alba L. to breed tolerant transgenic poplar to temperature stress. The plantlets of OsHSP26-overexpressed transgenic poplar showed more heathy phenotypic response than wild-type plants under both prolonged low- and high-temperature stress. While the SPAD value, which refers chlorophyll content, in wild-type plants decreased depending on the exposure time to the temperature stress, higher SPAD value were shown in the transgenic plants. The contents of total phenolic compounds in the transgenic plants were lower than those of the wild-type plants, and not significantly changed except in the treatment of prolonged low-temperature. However, the total flavonoids contents of the transgenic plants were dramatically increased under prolonged temperature stress. The DPPH scavenging activities of the transgenic plants were higher than those of the wild-type plants under temperature stress. Consequently, it was revealed that overexpressing OsHSP26 allow for P. alba to be tolerant to temperature stress.
        4,300원
        110.
        2017.04 구독 인증기관·개인회원 무료
        We performed a survey for flavivirus infection and distribution of Aedes albopictus that known as Zika and Dengue virus vector using black–light trap and BG-sentinel trap around urban area in Korea. Mosquitoes were collected in 27 cities during March to November (twice a month) year 2016. Total numbers of mosquitoes collected 102,102 including 19 species 8 genera during collecting period. Total 21,467 Ae. albopictus was collected that 20,961(24.3%) by BG-sentinel trap and 506 (3.2%) by Black-light trap in urban area. Trap index(trap/night) of Ae. albopictus was showed highest in Hamyang (TI:992.3) and lowest in Taebaek (TI:0.3) there was only collected by Black-light trap. A total of 894 pools from all collecting Ae. albopictus were performed a Flavivirus detection. Flavivirus was not detected during study period. This study may provide basic information for surveillance of imported diseases (include Zika virus) and vectors in Korea.
        111.
        2017.04 구독 인증기관·개인회원 무료
        Maruca vitrata larvae feed on flowers and pods of several leguminous crops, and can severely reduce seed yield. Adult emergence, mating and oviposition behaviors were observed in a 15h/9h=light/dark and 25℃ condition as a base study for monitoring. Emergence occurred mainly during the first five hours of scotophase. Mating occurred from the two days after emergence, and the mated females started to lay eggs from the next day. A maximal mating rate was observed in the night of five days. Mating occurred significantly more often during the time from 2 hours before to 3 hours after lights-off, but older females mated more frequently during the photophase. Electroanntennographic responses of males to some chemicals, and body extracts and volatile collections of females were measured
        112.
        2017.04 구독 인증기관·개인회원 무료
        Dermanyssus gallinae is parasitic to chicken, and they cause many damages such as disturbing sleep reducing for body weight and egg production by blood-sucking. To develop acaricide against D. gallinae, The acaricidal activity of 40 species plant extract were examined. Cnidium officinale extracted by Me-OH showed 82.0% acaricidal activity after treated 48 hrs at 4,000 ppm. The hexane fraction showed 92.4% mortality against D. gallinae at 48 hrs at 2,000 ppm. Purification of the biologically active constituents from the hexane extraction with acaricidal activity was done using silica gel open column chromatography and HPLC. H1122 fraction gave 80.9% mortality to D. gallinae at 400 ppm after treated 48 hrs. H1122 fraction was analyzed by GC-MS and NMR.
        113.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The extragalactic background suggests half the energy generated by stars was reprocessed into the infrared (IR) by dust. At z1.3, 90% of star formation is obscured by dust. To fully understand the cosmic star formation history, it is critical to investigate infrared emission. AKARI has made deep mid-IR observation using its continuous 9-band filters in the NEP field (5.4 deg2), using 10% of the entire pointed observations available throughout its lifetime. However, there remain 11,000 AKARI infrared sources undetected with the previous CFHT/Megacam imaging (r ~25.9ABmag). Redshift and IR luminosity of these sources are unknown. These sources may contribute signi cantly to the cosmic star-formation rate density (CSFRD). For example, if they all lie at 1< z <2, the CSFRD will be twice as high at the epoch. We are carrying out deep imaging of the NEP eld in 5 broad bands (g; r; i; z; and y) using Hyper Suprime-Camera (HSC), which has 1.5 deg field of view in diameter on Subaru 8m telescope. This will provide photometric redshift information, and thereby IR luminosity for the previously-undetected 11,000 faint AKARI IR sources. Combined with AKARI's mid-IR AGN/SF diagnosis, and accurate mid- IR luminosity measurement, this will allow a complete census of cosmic star-formation/AGN accretion history obscured by dust.
        4,000원
        114.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There exists strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies; however it is still under debate how such a relation comes about and whether it is relevant for all or only a subset of galaxies. An important mechanism connecting AGN to their host galaxies is AGN feedback, potentially heating up or even expelling gas from galaxies. AGN feedback may hence be responsible for the eventual quenching of star formation and halting of galaxy growth. A rich multi- wavelength dataset ranging from the X-ray regime (Chandra), to far-IR (Herschel), and radio (WSRT) is available for the North Ecliptic Pole field, most notably surveyed by the AKARI infrared space telescope, covering a total area on the sky of 5.4 sq. degrees. We investigate the star formation properties and possible signatures of radio feedback mechanisms in the host galaxies of 237 radio sources below redshift z = 2 and at a radio 1.4 GHz ux density limit of 0.1 mJy. Using broadband SED modelling, the nuclear and host galaxy components of these sources are studied simultaneously as a function of their radio luminosity. Here we present results concerning the AGN content of the radio sources in this eld, while also offering evidence showcasing a link between AGN activity and host galaxy star formation. In particular, we show results supporting a maintenance type of feedback from powerful radio-jets.
        3,000원
        115.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Earthworms, especially Eisenia andrei, are cultivated for a variety of purposes including waste disposal and compost production. In this study, bacteria from earthworm gut were cultured and the dominant species identified. Subsequently, we isolated bacteriophages able to lyse the isolated gut bacteria. Two dominant genera of gut bacteria, Aeromonas sp. and Citrobacter sp. were identified by using MALDI-TOF MS analysis and a library was constructed to find lytic phages. Phage EF1 showed lytic activity for C. freundii and two Citrobacter isolates, C. braakii and C. murliniae. These 3 species have similar sensitivities to EF1. Several aspects of the life cycle of EF1 were investigated by using C. freundii under optimal growth conditions. EF1 infects C. freundii with a moderate latent period, approximately 25 min, and a large burst size averaging 5 × 109 per infected cell. Moreover, the antimicrobial activity of EF1 was well maintained under diverse conditions including a broad temperature range of 40°C to 50°C and a wide pH range of 4 to 11. In conclusion, the results indicate that earthworm casting contain a wide range of bacteria species, for which there are various corresponding bacteriophages.
        4,000원
        118.
        2016.10 구독 인증기관·개인회원 무료
        The α-Gal epitope (Galα1,3Galα1,4GlcNAc-R) is responsible for hyperacute rejection (HAR) during transgenic pig-to-non-human primate xenotransplantation. To overcome HAR after xenografts, it is essential for the inactivation of α1,3Galactosyltransferase (GT) gene by the homozygotic knocked out of GT-/- and the isoglobotrihexosylceramide synthase (iGb3s-/-). This study was performed to investigate the generation and characterization of the α1,3GT-MCP/-MCP+iGb3-/- transgenic cells. Ear fibroblast cells from the GT-MCP/-MCP pig were cultured and used to positive control. For iGb3s knock out, the Cas9-GFP-iGb3s vector was transfected into the GT-MCP/-MCP cells. The Cas9-GFP-iGb3s transfected cells were sorted and sequenced for the selection of GT-MCP/-MCP+ iGb3s-/- cells. Among the three sorted cell lines, one transgenic cell line was homozygously deleted 3 bases and 10 bases in each chromosome, respectively. To characterize an expression of α-Gal epitope, a wild type and the transgenic cells were measured by FACS Aria using BS-IB4 lectin antibody. The expression of α-Gal epitope in GT-MCP/-MCP cells (<0.01 %) were significantly down-regulated to the range of wild type (99.4 %) fibroblast cells (p<0.05). To analyze the function of iGb3s, α -Gal epitope expressions were measured for the GT-MCP/-MCP, GT-MCP/-MCP+iGb3s-/+, and GT-MCP/-MCP+iGb3s-/-. The range was 95.8%, 94.2%, and 75.8%, respectively. Interestingly, there was a negative range (16.2%) of α-Gal epitope -/- section in GT-MCP/-MCP+iGb3s-/-, compared to 2.74% of GT-MCP/-MCP+iGb3s-/+ and 1.4% of WT, respectively. Our results demonstrated that iGb3s-/-combined with GT-/- had a function to inhibit α-Gal epitope expression in pig cells. Further studies are needed to evaluate the functions of double gene knock out to minimize a HAR response after xenotransplantation.
        119.
        2016.10 구독 인증기관·개인회원 무료
        The α-Gal epitope (Galα1,3Galα1,4GlcNAc-R) is responsible for hyperacute rejection (HAR) during transgenic pig-to-non-human primate xenotransplantation. There are genes related to the expression of α-Gal epitope such as α1,3Galactosyltransferase gene (GT-/-) and the isoglobotrihexosylceramide synthase (iGb3s-/-). This study was performed to investigate the expression of α-Gal epitope in the skin derived from GT-/- transgenic pig. The skin (7/1000 inches) was obtained by dermatome (Zimmer® Electric Dermatome) from one month old of wildtype (WT) and GT-/- piglets, respectively. The skins were fixed, dehydrated, cleaned, and embedded. To analyze the expression of α-Gal epitope, the paraffin section of WT and GT-/- were stained with BS-IB4 lectin and isoglobotrihexosylceramide synthase antibody. There was a strong BS-IB4 lectin signal in the skin of WT, but not detected in GT-/-. However, the iGb3s positive signals were stained in the skin of both WT and GT-/-. Taken together, it can be postulated that the knocked out of GT gene may not enough to inhibit the expression of α-Gal epitope. Further studies are needed to evaluate the functions of the double knock out of GT and iGb3s on the expression of α-Gal epitope.
        120.
        2016.10 구독 인증기관·개인회원 무료
        This study was conducted to review the family Psychidae in the Korean peninsula with taxonomic arrangement, some biological notes and phylogenetic analyses. In this study, totally 20 species of 8 genera belonging to 5 subfamilies in the family were recognized from Korea. Among them, a new subfamily Ceratostiinae subfam. nov. is proposed based on the type genus Ceratosticha Meyrick. Four new species are described as new to science. Also, six newly recorded species are first recorded in this study. In addition, ecological characteristics, distributional ranges, host plants and biological notes including life cycle and parasites on the larva were described. A phylogenetic and a molecular clock analysis were conducted to construct the systematic relationship and evolutionary process within the family Psychidae species.