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五峰垃圾填埋场渗滤液污染特征及处理系统 总被引:1,自引:0,他引:1
系统分析了五峰垃圾填埋场渗滤液中COD,BOD_5的季节变化特征,并对该填埋场的污水处理系统进行了研究和评价。 相似文献
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The 35S promoter of the cauliflower mosaic virus (CaMV) contains a tandem repeat of the sequence TGACG in the region -83 to -63. This 21-base pair (bp) sequence, called as-1, is involved in root expression of the 35S promoter. When inserted in a promoter of a gene expressed specifically in photosynthetic tissues, as-1 confers high level expression in roots. We have described a factor, ASF-1, that binds specifically to as-1 in vitro. There is a good correlation between ASF-1 binding affinity to as-1 related sequences in vitro and the function of these sequences in vivo. These results strongly suggest that ASF-1 is responsible for the function of as-1. Here we report the isolation of tobacco complementary DNA clones encoding two TGACG-sequence-specific binding-proteins (TGA1a and TGA1b). Sequence analysis of the cDNA clones shows that both proteins contain a basic region that shows high homology to a stretch of basic amino acids in the nuclear factors CREB, GCN4, and c-Jun to a 'leucine-zipper' region. On the basis of binding specificity we propose TGA1a to be a good candidate for ASF-1. 相似文献
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Auroral substorm response to solar wind pressure shock 总被引:1,自引:0,他引:1
Two cases of auroral substorms have been studied with the Polar UVI data, which were associated with solar wind pressure shock
arriving at the Earth. The global aurora activities started about 1–2 min after pressure shocks arrived at dayside magnetopause,
then nightside auroras intensified rapidly 3–4 min later, with auroral substorm onset. The observations in synchronous orbit
indicated that the compressing effects on magnetosphere were observed in their corresponding sites about 2 min after the pressure
shocks impulse magnetopause. We propose that the auroral intensification and substorm onset possibly result from hydromagnetic
wave produced by the pressure shock. The fast-mode wave propagates across the magnetotail lobes with higher local Alfven velocity,
magnetotail was compressed rapidly and strong lobe field and cross-tail current were built in about 1–2 min, and furthermore
the substorm was triggered due to an instability in current sheet. 相似文献
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Crystal structure of TFIID TATA-box binding protein. 总被引:48,自引:0,他引:48
D B Nikolov S H Hu J Lin A Gasch A Hoffmann M Horikoshi N H Chua R G Roeder S K Burley 《Nature》1992,360(6399):40-46
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The production of correctly spliced messenger RNA requires two catalytic splicing steps. During step II, exon 1 attacks an adenine-guanine (AG) dinucleotide at the 3' splice site. This AG is usually located between 18 and 40 nucleotides downstream from the branch site, and closer AGs are skipped in favour of AGs located more optimally downstream. At present, little is understood about how the correct AG is distinguished from other AGs. Here we describe a metazoan splicing factor (hSlu7) that is required for selection of the correct AG. In the absence of hSlu7, use of the correct AG is suppressed and incorrect AGs are activated. We investigated this loss of fidelity by analysing spliceosomes assembled in the absence of hSlu7. These studies reveal that exon 1 is loosely associated with these spliceosomes. Thus, the improperly held exon cannot access the correct AG, but can attack other AGs indiscriminately. We conclude that hSlu7 is required to hold exon 1 tightly within the spliceosome for attack on a prespecified AG. 相似文献
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