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        검색결과 52

        22.
        2014.10 구독 인증기관·개인회원 무료
        Insects impact human health through vector-borne diseases and cause major economic loses through damaging crops and stored agricultural products. Insect-specific growth regulators (IGR) represent attractive control agents because of their safety to the environment and humans. Here, we report identification of plant compounds that are antagonists of the insect-specific juvenile hormone (PJHANs), using the yeast two hybrid system transformed with the mosquito JH receptor as a reporter assay. We show that these compounds act by inhibiting larval growth and reproduction in mosquitoes. We also demonstrate that PJHANs affect the JH receptor, Methoprene-tolerant (Met), by disrupting its complex with CYCLE, formation of which is required for mediating JH action. We isolated five diterpene secondary metabolites with JH antagonist activity from two plants, Lindera erythrocarpa and Solidago serotina. They are effective in causing mortality of mosquito larvae at relatively low LD50 values. Two of these diterprenes affect Met function, leading to reduction in expression of Met target genes and causing retardation of follicle development in mosquito ovaries. Developing potent compounds counteracting JHaction (JH antagonists) would find a wider range of control applications. However, so far such JH antagonists have not been developed. Here, we report the discovery of potent JH antagonists in plants, which represents an innate resistance mechanism of plants against insect herbivores. These newly discovered plant JH antagonist compounds could be used as the starting material for developing novel insecticides.
        23.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the effects of different levels of soybean curd residue as an ingredient of TMR on growth performance and carcass characteristics of Holstein steers. Twenty four Holstein steers of 7 months age(average body weight 274.6 kg) were randomly allocated to 3 experimental groups, which contained 8animals per group during 15-months feeding trial. The treatments composed of the group fed concentrate and rice straw separately (Control), the group fed TMR containing low levels of soybean curd (T1), the group fed TMR containing high levels of soybean curd residue (T2). Body weight and average daily gain were not significantly different among the treatment groups during the feeding trial periods. Feed intake was not differ among treatment groups, but feed conversion ratio was significantly higher in T2 group compared to T1 group during late fattening stage (p<0.05). However, it was not different in overall average. According to the yield traits, carcass weight of control, T1 and T2 were 466.4, 451.1 and 460.1 kg, respectively. Back fat thickness, rib eye area and yield index were not different among the groups. The marbling score, meat color, texture and maturity in quality traits were not different among the treatment groups, but fat color was significantly higher in T2 group compared to T1 group (p<0.05). The quality grade (1+:1:2:3, NO.) tended to be higher for T1(0:2:1:5) and T2 (0:1:4:3) compared with the control (0:0:3:5). Therefore, these results indicated that TMR with soybean curd residue may be appropriate the growth performance and carcass characteristics of Holstein steers.
        4,000원
        27.
        2011.05 구독 인증기관·개인회원 무료
        Edible mushrooms have been used and researched as medicinal ingredients. They improve immunity and contain excellent anticancer components with large amounts of minerals such as iron, calcium, and potassium. Due to this reason, it has been hailed as a raw material for functional foods. Especially, β-glucan, known to be contained in Ganoderma incidum Karst, Coriolus versicolor, and Phellinus linteus, was reported to inhibit proliferation of cancer cells by activating immune function (macrophages, natural killer cells and T-cells). In addition, mushroom polysaccharides dissolve in water but are undigested ingredients, resulting in stimulating the immune system as well as staying of parasympathetic nervous system in the stomach for a long time. As a result, they induce increase of T-cells and NK cell that attacks cancer cell and has effect on the discharge of body's waste products, blood purification, and constipation improvement. In this study, we report the culture characteristics of Sparassis crispa as to the medium growth compositions, yeast, and elicitor treatments to investigate the optimal condition for the highest β-glucan production in mushrooms.
        31.
        2007.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        4,900원
        32.
        2006.12 구독 인증기관 무료, 개인회원 유료
        Temperature signaling can be initiated by members of transient receptor potential (thermo-TRP) channels. Hot and cold substances applied to teeth usually elicit pain sensation. Since odontoblasts constitute a well-defined layer between the pulp and the mineralized dentin, being first to encounter thermal stimulation from oral cavity, they may be involved in sensory transduction process, in addition to their primary function as formation of dentin. We investigated whether thermo-TRP channels are expressed in a odontoblast cell line, MDPC-23. The expressions of thermo-TRP channels were examined using reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, fluorometric calcium imaging. Analysis of RT-PCR revealed mRNA expression of TRPV1, TRPV2, TRPV4 and TRPM8, but no TRPV3, TRPA1. Immunohistochemical approach failed to detect TRPV1 expression. Whereas the application of 4-phorbol-12,13-didecanoate(10 μM, a TRPV4 agonist), menthol(1 mM, a TRPM8 agonist) and icilin(10 μM, a TRPM8 agonist) produced the enhancement of intracellular calcium concentration, capsaicin(1 μM, a TRPV1 agonist) did not. Our results suggest that subfamily of thermo-TRP channels expressed in odontoblasts may serve as thermal or mechanical transducer in teeth.
        4,000원
        33.
        2005.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To evaluate parameters influencing on the dust removal of the High Temperature Filter(HTF) system, a computer simulation of fluid dynamics inside the system had been performed. The results showed that the optimum pulse jet periods were 50ms and 90ms for the 1000mm and 1500mm long filter elements respectively. Dust removal effect was very excellent under the pulse jet pressure of 3 bar. But the distance between the pulse jet nozzle and the venturi of a filter element had no meaningful effect on the performance with the variation from 5mm to 10mm. Compared to the dispersion mode of pulse jet, the collective mode of pulse jet flow was preferable in maintaining the pressure inside the system stable.
        4,000원
        34.
        2004.12 구독 인증기관 무료, 개인회원 유료
        Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo. Human ES cells have the capacity to differentiate into various types of cells in the body. Human ES cells are indefinite source of cells for cell therapy in various degenerative disorders including neuronal disorders. Directed differentiation of human ES cells is a prerequisite for their clinical application. The objective of this study is to develop the culture condition for the derivation of neural precursor cells from human ES cells. Neural precursor cells were derived from human ES cells in a stepwise culture condition. Neural precursor cells in the form of neural rosette structures developed into neurospheres when cultured in suspension. Suspension culture of neurospheres has been maintained over 4 months. Expressions of nestin, soxl, sox2, pax3 and pax6 transcripts were upregulated during differentiation into neural precursor cells by RT-PCR analysis. In contrast, expression of oct4 was dramatically downregulated in neural precursor cells. Immunocytochemical analyses of neural precursor cells demonstrated expression of nestin and SOX1. When induced to differentiate on an adhesive substrate, neuro-spheres were able to differentiate into three lineages of neural systems, including neurons, astrocytes and oligo-dendrocytes. Transcripts of sox1 and pax6 were downregulated during differentiation of neural precursor cells into neurons. In contrast, expression of map2ab was elevated in the differentiated cells, relative to those in neural precursor cells. Neurons derived from neural precursor cells expressed NCAM, Tuj1, MAP2ab, NeuN and NF200 in immunocytochemical analyses. Presence of astrocytes was confirmed by expression of GFAP immuno-cytochemically. Oligodendrocytes were also observed by positive immuno-reactivities against oligodendrocyte marker O1. Results of this study demonstrate that a stepwise culture condition is developed for the derivation of neural precursor cells from human ES cells.
        4,000원
        35.
        2002.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The color stability and purity from OLED is of current interest. Aggregation of dyes alters the device color after fabrication of the devices. Exciplex and electroplex formations have been proposed to explain the aggregate color change. We investigate the possibility of exciplex formation and propose the new electroplex state that can cause the bathochromic shift of the electroluminescence spectrum from the devices with TPD/PBD layers. The photoluminescence maximum of the device was 420nm, and the electroluminescence maximum of the device to became 480nm. The bathochromic shift cannot be attained with photoluminescence study with highly concentrated TPD/PBD mixture. This clearly indicates that the 480nm spectrum of the devices is not resulted from the exciplex formation with TPD and PBD. We observed the overshoot in EL spectrum from the OLEDs. The most intense overshoot was observed at 460nm, which may be due to the aggregates that are formed after the electric field has been removed from the devices.
        4,000원
        37.
        2015.09 서비스 종료(열람 제한)
        Acute myocardial infarction (AMI) involving two simultaneous vascular territories of acute transmural ischemia is known as a double or combined myocardial infarction. This well described but extremely rare phenomenon may be related to the fact that AMI with multiple vessel obstruction often causes extensive myocardial injury and death before hospitalization. We reported the first case of 45-year-old man with AMI occluded left anterior descending artery and right coronary artery simultaneously in Korea.
        38.
        2015.07 서비스 종료(열람 제한)
        Rice is a staple food crop for more than half of the world population. Severe losses of rice production was caused by various environmental conditions such as cold, heat and flooding annually. Rice is a highly sensitive to low temperature below 15-20 ℃ because of originating from tropical or subtropical climates. Especially, seedling of rice is easily damaged to low temperature and result in seedling yellowing, growth retardation, reduced tillering and yield losses at last. We used a recombinant inbreeding lines (RIL) population of 384 individuals derived from a cross between Hanareum 2, a highly cold sensitive variety and Unkwang, a cold tolerant variety for molecular mapping of QTLs related to cold tolerance. Seedling discoloration of each lines and parents caused by cold response were investigated in field condition after transplanting. And leaf samples of RIL population were collected for evaluation of chlorophyll content using 80% acetone extraction. The seedling of each lines and parents was subjected to low temperate by 5~13 ℃ during 14 days. The cold recovery score (CRS) of RILs was recorded after 4 days recovery period according to standard evaluation system (SES, IRRI). Total of eight QTLs were detected on chromosome 1, 7, 8, 10, 11 and 12 using cold tolerance traits, chlorophyll content, seedling discoloration and cold recovery score in 384 RILs. The qCRS12, which detected on chromosome 12 between two flanking markers id12002113, id12002563 (1.1 Mbp) showed 25 LOD score with 26% of phenotypic variation of cold recovery score in RILs population. The positive allele contributing to cold tolerance came from the cold tolerant parent Unkwang. The result may provide useful information for a marker-assisted breeding program to improve cold tolerant in rice.
        39.
        2015.06 서비스 종료(열람 제한)
        Diffuse involvement of the right pulmonary artery (PA) associated with fistula between the PA and coronary artery is report-ed in a woman with Takayasu’s arteritis. Both the subclavian arteries were totally occluded and drained by the meanderinged artery arising from both common carotid arteries. Lung perfusion scan revealed perfusion defect of right lung. Two fistulas were identified. A large fistula was between the right PA and left circumflex artery. A small fistula was between the right PA and left anterior descending artery. This is a rare case of Takayasu’s arteritis presenting with a coronary – pulmonary artery fistula that is secondary to a diffuse unilateral involvement of PA.
        40.
        2014.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Next Generation Small Satellite-1 (NEXTSat-1) is scheduled to launch in 2017 and Instruments for the Study of Space Storm (ISSS) is planned to be onboard the NEXTSat-1. High Energy Particle Detector (HEPD) is one of the equipment comprising ISSS and the main objective of HEPD is to measure the high energy particles streaming into the Earth radiation belt during the event of a space storm, especially, electrons and protons, to obtain the flux information of those particles. For the design of HEPD, the Geometrical Factor was calculated to be 0.05 to be consistent with the targets of measurement and the structure of telescope with field of view of 33.4° was designed using this factor. In order to decide the thickness of the detector sensor and the classification of the detection channels, a simulation was performed using GEANT4. Based on the simulation results, two silicon detectors with 1 mm thickness were selected and the aluminum foil of 0.05 mm is placed right in front of the silicon detectors to shield low energy particles. The detection channels are divided into an electron channel and two proton channels based on the measured LET of the particle. If the measured LET is less than 0.8 MeV, the particle belongs to the electron channel, otherwise it belongs to proton channels. HEPD is installed in the direction of 0°,45°,90° against the along-track of a satellite to enable the efficient measurement of high energy particles. HEPD detects electrons with the energy of 0.1 MeV to several MeV and protons with the energy of more than a few MeV. Thus, the study on the dynamic mechanism of these particles in the Earth radiation belt will be performed.
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