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        검색결과 78

        21.
        2016.10 구독 인증기관·개인회원 무료
        Prolonged communication between oocytes and the surrounding somatic cells is one of the unique reproductive physiology in canine. Paracrine Kit ligand (KITL) signaling is a well-known communication between granulosa cells and the oocyte. KITL is a cytokine growth factor secreted by granulosa cells that signals via the c-kit receptor expressed by oocytes. Paracrine factors, including growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15), exert their effects by binding with the kinase receptors expressed on the granulosa cells. However, the regulations of GDF9 and BMP15 in the canine KITL expression are currently poorly understood. Therefore, we investigated the effects of GDF9 and BMP15 on the expression of KITL in canine ovarian granulosa cells in vitro. In Annexin V assay recombinant GDF9 and BMP15 did not induce apoptosis in the cultured ovarian granulosa cells. When treated, FSH significantly increased KITL expression, and hCG suppressed its expression. When both FSH and hCG were treated, the expression of KITL was affected by GDF9 and BMP15 in dose and time dependent manner in the luteal granulosa cells. GDF9 (10 ng/mL) significantly decreased KITL expression after12 h. BMP15 (10 ng/mL) significantly also decreased KITL expression after 24 h. Western blot and immunochemistry results indicate that GDF9 activated Smad2/3. After blocking ALK 4/5/7 receptors by SB, GDF9 failed to activate Smad2/3, also BMP15 did not activate Smad1/5/8 after blocking ALK 2/3/6 receptors by DM. So GDF9 exerts its effects via using ALK 4/5/7 receptors to activate SMAD2/3 signaling, and BMP15 binds ALK 2/3/6 receptors to activate SMAD1/5/8 signaling. The expression of KITL was not changed by SB or DM treatment. However, the effect of GDF9 and BMP15, which decreased the expression of KITL, was suppressed by SB or DM treatment. In conclusion, this study provides the first evidence that recombinant GDF9 and BMP15 decrease KITL expression in canine ovarian granulosa cells.
        22.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This review presents current progress in the preparation methods of liquid crystalline nanocarbon materials and the liquid crystalline spinning method for producing nano-carbon fibers. In particular, we focus on the fabrication of liquid crystalline carbon nanotubes by spinning from superacids, and the continuous production of macroscopic fiber from liquid crystalline graphene oxide.
        4,000원
        23.
        2015.09 KCI 등재 구독 인증기관·개인회원 무료
        We have been performing daily VLBI monitoring of the ux density of Sagittarius (Sgr) A* at 22 GHz from February 2013 to August 2014 using a sub-array of the Japanese VLBI Network (JVN). The purpose of this monitoring is to explore the ux density variability at daily time resolution for a period longer than one year with the G2 cloud approaching. The ux density of Sgr A* is basically stable during the observational period, though there are some small variations. The average and scattering range are consistent with the previously observed values. We have observed no strong are of Sgr A* although it is near the expected peri-center passing.
        24.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polarbear is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic in ation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1,274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.
        3,000원
        25.
        2014.10 구독 인증기관·개인회원 무료
        In the present study, we report two lepidopteran pests on the cones of Abies koreana E. H. Wilson; Cydia sp. of Tortricidae and Dioryctria abietella Denis et Schiffermüller of Pyralidae. Larvae of these species bored tunnels inside the immature cones of the host plant. Damaged cones are easy to spot by reddish brown excretion from the pest entry holes, and the cones severly damaged by the larvae becomes crooked. Damage rate on the cones reached up tp 71% from the collection site. Regarding the two pests, some basic information such as collection records, morphological characters, and ecology were provided.
        26.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, poly(amic acid) was prepared via a polycondensation reaction of 3,3'-dihydroxybenzidine and pyromellitic dianhydride in an N-methyl-2-pyrrolidone solution; reduced graphene oxide/polybenzoxazole (r-GO/PBO) composite films, which significantly increased the electrical conductivity, were successfully fabricated. GO was prepared from graphite using Brodie's method. The GO was used as nanofillers for the preparation of r-GO/PBO composites through an in situ polymerization. The addition of 50 wt% GO led to a significant increase in the electrical conductivity of the composite films by more than sixteen orders of magnitude compared with that of pure PBO films as a result of the electrical percolation networks in the r-GO during the thermal treatment at various temperatures within the films.
        3,000원
        27.
        2013.12 구독 인증기관 무료, 개인회원 유료
        The swine is one of the most widespread mammalian throughout the whole world. Presently, many studies concer-ning microsatellites in swine, especially domestic pigs, have been carried out in order to investigate general diversity patterns among either populations or breeds. Until now, a lot of time and effort spend into a single PCR method. But simple and more rapid multiplex PCR methods have been developed. The purpose of this study is to develop a robust set of microsatellites markers (MS marker) for traceability and individual identification. Using multiplex-PCR method with 23 MS marker divided 2 set, various alleles occurring to 5 swine breed (Berkshire, Landrace, Yorkshire, Duroc and Korea native pig) used markers to determine allele frequency and heterozygosity. MS marker found 4 alle-les at SW403, S0227, SWR414, SW1041 and SW1377. The most were found 10 alleles at SW1920. Heterozygosity represented the lowest value of 0.102 at SWR414 and highest value of 0.861 at SW1920. So, it was recognized appro-priate allele frequency for individual identification in swine. Using multiplex-PCR method, MS markers used to determine individual identification biomarker and breed-specific marker for faster, more accurate and lower analysis cost. Based on this result, a scientific basis was established to the existing pedigree data by applying genetics additio-nally. Swine traceability is expected to be very useful system and be conducted nationwide in future.
        4,000원
        28.
        2013.10 구독 인증기관·개인회원 무료
        Anoplophora isa moderate-sized genus with 36 species of woodboring cerambycid beetles that occur throughout Asia, with the highest diversity in the tropical and subtropical region. Two species, A. chinensis (Forster) and A. glabripennis (Motchulsky) are known in the Korean peninsula. The latter is an infamous invasive species, commonly called the Asian longhorned beetle, in the U.S. causing economic damage on hard woods. For the present study, we carried out field surveys from 2010 to 2013 and literature review on the host plants of Korean Anoplophora species. A. chinensis is associated with 14 host plant species in 4 families and A. glabripennis 17 species of 11 families. Most importantly, the Manchurian striped maple, Acer tegmentosum Maxim. (Aceraceae), is newly recognized as a host of the Asian longhorned beetle. In the present study, a revised host plant checklist of Korean Anoplophora species is provided, with correction of scientific and Korean names of the host plants.
        29.
        2013.10 구독 인증기관·개인회원 무료
        The Cerambycidae is a very diverse family in Chrysomeloidea (Insecta: Coleoptera), and the members are commonly called as longhorn beetles, long-horned beetles or longicorn beetles. The family is comprised of approximately 25,000 described species in nine subfamilies worldwide, and 311 species are known from Korean insect fauna. Most species are associated with woods and shrubs or live on herbaceous vegetation in open areas. Cerambycid larvae are primarily borers in deadwood. Some species develop in living trees and cause damage on host plants by boring heart wood and making galleries. As the results of four year field surveys (from 2010 to 2013) and literature review, host plants of 181 species of Korean Cerambycidae are revised, including thirteen new cerambycid-host associations, and more than 179 host plants species of 107 genera in 44 families are compiled. Among them, most common host plants are belonged to mainly four families: Ulmaceae, Pinaceae, Fagaceae and Betulaceae. Additionally, Acer tegmentosum Maxim. (Aceraceae) is newly recognized as a host plant of the Asian longhorned beetle, Anoplophora grabripennis (Motchulsky) in South Korea.
        30.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기계이앙과 무논점파재배시 간단관개가 벼의 생육, 쌀수량과 미질에 미치는 영향과 물절약 효과를 구명하고자 2009년과 2010년에 시험한 결과는 다음과 같다. 관개량은 기계이앙이 801mm, 무논점파재배가 717mm로 기계이앙이 더 많았다. 관개방법별로는 기계이앙재배에서 관행관개가 899mm, 간단관개가 703mm이었고, 무논점파재배에서는 관행관개가813mm, 간단관개가 621mm이었다. 간단관개는 관행관개에비해 22~24%의 관개수를 절약할 수 있었으며, 이에 따른 단위 관개량당 쌀수량인 물생산성은 기계이앙과 무논점파재배모두 간단관개가 높게 나타났다. 초장, 간장, 수장은 간단관개와 관행관개에 차이가 없었으나, 분얼수는 간단관개에서 다소높았다. 수량 및 수량구성요소 모두 관개방법별 유의적인 차이가 없었으며, 완전미 비율, 단백질 함량도 유의한 차이가 나타나지 않았다. 이상의 결과에서 간단관개를 하여도 관행관개방식에 비해 벼의 생육 및 수량, 그리고 미질에 차이가 없었던 반면 물생산성을 높이는 결과를 보였다. 따라서 벼 재배시용수절약 측면에서 간단관개의 적용이 가능할 것으로 보인다.간단관개를 포함한 종합적인 재배기술을 연구하여 관개비용의절감이나 수량의 증대 같은 이익적 요소들이 제공된다면 농가에서도 관심을 갖게 될 것으로 생각된다.
        4,000원
        32.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyacrylonitrile (PAN) copolymers of different molecular weights were synthesized by a suspension polymerization and precipitation polymerization method. The rheology behaviors of the synthesized PAN copolymers were investigated in relation to their molecular weight, solid content and melting temperature. The influence of "historical effects" on the spinning solution of PAN was studied by analyzing the laws of viscosity considering the diversification time and temperature. The viscosity disciplines of each spinning solution conformed well to the rheological universal laws in a comparison of the suspension polymerization product with that of precipitation polymerization. Viscosity changes in the swelling process of dissolution were gentler in the suspension polymerization product; a small amount of water will quickly debase the solution viscosity, and high-speed mixing can greatly shorten the time required by the spinning solution to reach the final viscosity.
        4,000원
        33.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alpha-tocopherol as an antioxidant acts in preservation of chilled semen by preserving cell membrane damage from lipid peroxidation. Optimum concentrations of α-tocopherol in egg yolk-citrate (EYC) extender need to be studied in crossbred bull’s semen. Different concentrations of α-tocopherol viz. 0, 1, 2, 4 and 6mg per ml of extender were used. Semen was collected once a week from four bulls used to regular collection, aged 4 to 7 years, weighing 320 to 450 kg, and with body condition score 4 to 4.5 and scrotal circumference 23 to 32 cm. Semen was evaluated routinely and sperm morphology was viewed under light microscope at ×1,000 magnification after fixing with buffered formal saline. Over 90% had normal head, acrosome, mid-piece and tail. Semen was diluted with egg-yolk-citrate extender to produce 15×106 spermatozoa/ml and 0, 1, 2, 4 and 6 mg/ml α-tocopherol were added. The semens amples were kept at 8℃. Sperm motility and viability were examined daily up to 5 days under light microscopy at ×200 magnification. Sperm viability was acceptable (≥40%) up to the 4th day with all concentrations of α-tocopherol and up to the 5th day with 2 mg/ml α-tocopherol. Sperm motility was acceptable (≥40%) up to the 3rd day irrespective of α-tocopherol concentration, and up to the 4th day with 2 mg/ml α-tocopherol. It is suggested that the lifespan of chilled semen may be extended up to 4 days by adding 2mg/ml α-tocopherol.
        4,000원
        35.
        2011.11 구독 인증기관·개인회원 무료
        Korea National Arboretum (KNA) is located in Gwangneung forest, between Namyangju-si and Pocheon-si, in Gyeonggi province. In KNA, there are 15 specialized plant gardens. The woody plants of 1,863 species and the herbaceous plants of 1,481 species have been maintained in these gardens for 500 years. KNA have suitable environments for fungal growth. Despite floral diversity in there, the intensive researches on fungal flora have not been studied to date. Therefore, in order to get informations on fungal flora, regular field trips were made to this area and fresh fungal specimens were collected from there for 48 days from May in 2007 to November in 2010. Total 1,522 higher fungal specimens were collected in Gwangneung forest. All the collected specimens were identified and classified in 8 classes, 19 orders, 69 families, 267 genera and 454 species, and deposited in the herbarium of Korea National Arboretum (KNA). Among the identified specimens, sixteenspecies were confirmed as new to Korea as follows: Cudoniella acicularis, Discina ancilis, Helvella costifera, Entoloma cephalotrichum, Entoloma lepidissimum, Mycena leptocephala, Naematoloma gracile, Sistotrema octosporum, Hydnellum peckii, Lachnellula calyciformis, Amanita cockeri f. roseotinctata, Micromphale foetidum, Mycena corynephora, Clitocybe lateritia, Physisporinus vitreus, and Datronia stereoides. Literature cited 1. 김현중, 한상국. 2008. 광릉의 버섯. 국립수목원. 420pp. 2. 今關六也, 本鄕次雄. 1987. 原色日本菌類圖鑑(I). 保育社. 325pp. 3. Breitenbach, J. and Kränzlin, Fred. 1984. Fungi of Switzerland: 1. Ascomycetes. Mykologia Luzern. 310pp. 4. Breitenbach, J. and Kränzlin, Fred. 1986. Fungi of Switzerland: 2. Non gilled fungi. Mykologia Luzern. 412pp. 5. Breitenbach, J. and Kränzlin, Fred. 1995. Fungi of Switzerland: 4. Agarics 2nd part. Mykologia Luzern. 368pp. 6. Singer, R. 1986. The Agaricales in Modern Taxonomy. Koeltz Scientific Books. 7. Smith, A. H., Smith, H. V. and Weber N. S. 1979. How to know the gilled mushrooms. Wm. C. Brown Company Publishers. pp. 27, 263, 286-287.
        37.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        탄자니아(United Republic of Tanzania)의 연방인 잔지바르의 옥수수 종자보급 개선을 목적으로 자유방임품종4종 (Tuxpeno-1,Staha, Situka, TMV-1)을 탄자니아 본토로부터 2006년도에 도입하여 키짐바니 농업연구소에서 적응시험을 수행하였다. Tuxpeno-1이 3.9 t ha-1로써 네 품종 중 수량이 가장 높았으며, Staha는 3.8 t ha-1, Situka는 3.0 t ha-1, 그리고 TMV-1은 2.0 t ha-1의 수량을 보였다. 이는 각 품종들의 잠재수량성(potential yield)과 비교하여 77%, 72%,67%, 그리고 47% 정도의 수량이다. 수량 차이가 많이 나는 이유로는 양분의 부족이 가장 큰 원인으로 판단된다. 잔지바르의 환경에서 생육이 부진한 TMV-1과 병해충 저항성이 약했던 Situka품종은 보급 품종에서 제외되었다. 키짐바니 농업연구소에서는 본시험 이후 Tuxpeno-1와 Staha 품종의 종자를 생산하여 농가에 보급하고 있다.
        4,000원
        38.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The authors have demonstrated white oraganic light-emitting diodes (WOLED) using 1,4-bis[2-(4'-diphenylaminobiphenyl-4-yl)vinyl]benzene as fluorescent blue emitter and iridium(III) bis(5-acetyl-2-phenylpyridinato-N,C2') acetylacetonate as phosphorescent red emitter. The optimized WOLED using red host material as bis(2-methyl-8-quinolinato) -4-phenylphenolate exhibited proper color stability in comparison with the control device using 4,4'-N,N'-dicarbazole-biphenyl as red host. The white device showed a maximum luminance of 21100 cd/m2 at 14 V, luminous efficiency of 9.7 cd/A at 20 mA/cm2, and Commission Internationale de I'Eclairage (CIEx,y)coordinates of (0.32, 0.34) at 1000 cd/m2. The devices also exhibited the color shift with δCIEx,y coordinates of ± (0.01,0.01) from 100 to 20000 cd/m2.
        4,000원
        40.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The importance of nanopore structures of carbons is shown in terms of interaction potential for various molecules including supercritical gases such as H2 and CH4. The key factors for adsorption of supercritical H2 and CH4 are shown for single wall carbon nanohorn, single wall carbon nanotube, and double wall carbon nanotube. The cluster formation of molecules is a key process for water adsorption on hydrophobic carbon nanopores. The X-ray absorption spectroscopic examination elucidates an explicit dehydration structure of ions confined in carbon nanopores.
        3,000원
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