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        검색결과 2,998

        1841.
        2009.05 구독 인증기관·개인회원 무료
        The present investigation establishes deltamethrin resistance in the common bed bug, Cimex lectularius, populationcollected from New York City (NY-BB). The mortality resistance ratio indicated that NY-BB population was 264-fold more resistant to 1% deltamethrin in contact bioassay compared to one insecticide- susceptible population collected in Florida (FL-BB). Specific enzyme activities (general esterase, glutathione S-transferase, and 7-ethoxycoumarin O-deethylase) of NY-BB were not statistically different from those of FL-BB, indicating that the metabolic factors are not associated with the deltamethrin resistance in NY-BB. Complementary DNA fragments that encoded the open reading frame of voltage-sensitive sodium channel α-subunit genes from the FL-BB and NY-BB were obtained by homology probing PCR and sequenced. Sequence alignment of the internal and 5’ and 3’ RACE fragments generated a 6500 bp cDNA sequence contig, which was composed of a 6084 bp open reading frame (ORF) encoding 2027 amino acid residues and 186 bp 5’ and 230 bp 3’ untranslated regions (5’ and 3’UTRs, respectively). Sequence comparisons of the complete open reading frames of the sodium channel genes identified two point mutations (V419L and L925I) that were presented only in the NY-BB population. L925I, located the intracellular loop between IIS4 and IIS5, has been previously found in the pyrethroid-resistant populations of whitefly (Bemisia tabaci) that was more than 100-fold resistant to fenpropathrin. V419L, located in the IS6 transmembrane segment, is a novel mutation. This evidence suggests that the two mutations are likely the major resistance-causing mutations in the deltamethrin-resistant NY-BB via a knockdown-type nerve insensitivity mechanism.
        1842.
        2009.05 구독 인증기관·개인회원 무료
        To investigate the ecological emergence of pine sawyer beetle adult, it was examined the escape time and period and daily escape according to the tree species at Cheongwon, Chungbuk from 2006 to 2008. In the emergence chamber with non-shading treatment, the adults began to escape on May 6 in Pine and Korean white pine, May 13 in Japanese larch, and the last day of emergence was examined the beginning to Middle of June in Pine tree, middle to last of June in Korean white pine, last of May in Japanese larch, it showed the difference among tree species. In the emergence chamber with shade treatment, the first day of emergence of adult was delayed the eleven to sixteen days and showed lower 2.22℃ in temperature compare to the emergence chamber with non-shading treatment. Escape period did not show the difference between males and females. Daily emergence was escaped throughout 24 hrs. Number of emergence adult in daily hours was highest emerged with 22.8% in 12-14:00 and lowest in 06-08:00. Among escaped adults from shaded chamber in 2007, ratio of the adults of one generation per year was showed 98.8% and ratio of one generation in two year was observed 1.1 % in 2008. From 2006 to 2008, sex ratio of emerged adult from Korean white pine was showed 0.53-0.58 and its average was 0.54.
        1849.
        2009.04 구독 인증기관·개인회원 무료
        1855.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is focused on the synthesis of urea and amide derivatives particularly, since the amide moiety is an essential binding group at the binding site. Urea derivatives 3-7 and 13-14 were obtained by reaction of 2-aminopyrimidines and other amines with diverse isocyanates in pyridine as a solvent under reflux. The urea derivatives were obtained in low yield because of the highly electron deficient nature of the amino group of the 2-aminopyrimidine. Amide derivatives 8-10 were obtained in moderate yields by reaction of compound 1 with aryl chloride derivatives. Also, arylamine 11 was synthesized by Buchwald-Hartwig amination in moderate yields. Most of the compound did not show good activity against A375P melanoma cells, compared with Sorafenib as control compound.
        4,000원
        1856.
        2009.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The e-CALLISTO is a global network of frequency-agile solar radio spectrometers that was constructed in a collaboration between Swiss Federal Institute of Technology Zurich (ETH Zurich) and local host institutes. It is intended to monitor solar radio bursts 24 hours a day in frequency range between 45 MHz and 870 MHz. One of e-CALLISTO spectrometer was installed at Korea Astronomy and Space Science Institute (KASI) in 2007 October. The spectrometer gets signals from a horizontally polarized log-periodic antenna mounted on an automatic Sun-tracking system. Tracking status and data are monitored in Space Weather Monitoring Laboratory (SWML) of KASI in real time, and flare time data are transferred to ETH Zurich data archive daily. Using this spectrometer we obtained a couple of type II solar radio bursts on 2007 December 31, and found that these bursts are associated with a CME which occurred on the east limb.
        4,000원
        1857.
        2008.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Using the MHD coronal seismology technique, we estimated the magnetic field for three spicules observed in 2008 June. For this study, we used the high resolution Ca II H line (3968.5 ˚A) images observed by the Hinode SOT and considered a vertical thin flux tube as a spicule model. To our knowledge, this is the first attempt to estimate the spicule magnetic field using the Hinode observation. From the observed oscillation properties, we determined the periods, amplitudes, minimum wavelengths, and wave speeds. We interpreted the observed oscillations as MHD kink waves propagating through a vertical thin flux tube embedded in a uniform field environment. Then we estimated spicule magnetic field assuming spicule densities. Major results from this study are as follows : (1) we observed three oscillating spicules having durations of 5-7 minutes, oscillating periods of 2-3 minutes, and transverse displacements of 700-1000 km. (2) The estimated magnetic field in spicules is about 10-18 G for lower density limit and about 43-76 G for upper density limit. (3) In this analysis, we can estimate the minimum wavelength of the oscillations, such as 60000 km, 56000 km, and 45000 km. This may be due to the much longer wavelength comparing with the height of spicules. (4) In the first event occurred on 2008 June 03, the oscillation existed during limited time (about 250 s). This means that the oscillation may be triggered by an impulsive mechanism (like low atmospheric reconnection), not continuous. Being compared with the ground-based observations of spicule oscillations, our observation indicates quite different one, i.e., more than one order longer in wavelength, a factor of 3-4 larger in wave speed, and 2-3 times longer in period.
        4,000원
        1858.
        2008.12 구독 인증기관 무료, 개인회원 유료
        4,000원
        1859.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A group of new N,N-bis(5-acetylpyridin-2-yl)phenylamine derivatives was synthesized in good yield applying an optimized Buchwald-Hartwig amination protocol. The synthesized compounds showed UV absorption maxima in the range of 320-360 nm, and showed good luminescence at dilute concentrations in the blue region of the spectra (in the range of 480-497 nm). They showed also a bathochromic shift associating the increase in solvent polarity. The synthesized compounds could be investigated for use in OLEDs or as potential monomers for PLEDs.
        4,000원
        1860.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        6,300원