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        검색결과 2

        1.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A growing body of evidence has been supporting the existence of so-called "dark molecular gas" (DMG), which is invisible in the most common tracer of molecular gas, i.e., CO rotational emission. DMG is be- lieved to be the main gas component of the intermediate extinction region from Av~0.05-2, roughly corresponding to the self-shielding threshold of H2 and 13CO. To quantify DMG relative to HI and CO, we are pursuing three observational techniques; HI self-absorption, OH absorption, and THz C+ emission. In this paper, we focus on preliminary results from a CO and OH absorption survey of DMG candidates. Our analysis shows that the OH excitation temperature is close to that of the Galactic continuum back- ground and that OH is a good DMG tracer co-existing with molecular hydrogen in regions without CO. Through systematic "absorption mapping" by the Square Kilometer Array (SKA) and ALMA, we will have unprecedented, comprehensive knowledge of the ISM components including DMG in terms of their temperature and density, which will impact our understanding of galaxy evolution and star formation profoundly.
        3,000원
        2.
        2009.05 구독 인증기관·개인회원 무료
        Bacillus thuringiensis, an entomopathogenic bacterium belonging to the B. cereus group, harbors numerous extra-chromosomal DNA molecules whose sizes range from 2 to 250 kb. In this study, we used a plasmid capture system (PCS) to clone three small plasmids from B. thuringiensis subsp. kurstaki K1 using PCS which were not found in B. thuringiensis subsp. kurstaki HD-1, and determined the complete nucleotide sequence of plasmid pK1S-1 (5.5 kb). Of the six putative open reading frames (ORF2-ORF7) in pK1S-1, ORF2 (MobK1) showed approximately 90% aa identity with the Mob-proteins of pGI2 and pTX14-2, which are rolling circle replicating group VII (RCR group VII) plasmids from B. thuringiensis. In addition, a putative origin of transfer (oriT) showed 95.8% identity with those of pGI2 and pTX14-2. ORF3 (RepK1) showed relatively low aa identity (17.8-25.2%) with the Rep protein coded by RCR plasmids, however. The putative double-strand origin of replication (dso) and single-strand origin of replication (sso) of pK1S-1 exhibited approximately 70% and 64% identities with those of pGI2 and pTX14-2. ORF6 and 7 showed greater than 50% similarities with alkaline serine protease, which belongs to the subtilase family. The other 2 ORFs were identified as hypothetical proteins. To determine the replicon of pK1S-1, seven subclones were contructed in the B. t huringiensis ori-negative pHT1K vector and were electroporated into a plasmid cured B. thuringiensis strain. The 1.6 kb region that included the putative ORF3 (Rep1K), dso and ORF4, exhibited replication ability. These findings identified pK1S-1 as a new RCR group VII plasmid, and determined its replication region.