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81.
82.
Scientists and surgeons 总被引:1,自引:0,他引:1
F D Moore 《Science (New York, N.Y.)》1972,176(39):1100-1102
83.
Infants 3 weeks, 8 weeks, and 14 weeks old were presented with checkerboard patterns which differed in the number of squares they contained. The older the infants, the more complex was the checkerboard that they looked at longest. This result does not appear to depend on changes in visual acuity or accommodation related to age. 相似文献
84.
Norepinephrine: release from brain by d-amphetamine in vivo 总被引:1,自引:0,他引:1
After injection of H(3)-norepinephrine into the left lateral cerebral ventricle of cats, the lateral and third cerebral ventricles were perfused with an artificial cerebrospinal fluid. Addition of d-amphetamine to the perfusion fluid caused a significant increase in the concentration of H(3)-norepinephrine in the effluent. 相似文献
85.
86.
Human chromosome 12 is required for elevated HIV-1 expression in human-hamster hybrid cells 总被引:24,自引:0,他引:24
C E Hart C Y Ou J C Galphin J Moore L T Bacheler J J Wasmuth S R Petteway G Schochetman 《Science (New York, N.Y.)》1989,246(4929):488-491
Host cell factors act together with regulatory genes of the human immunodeficiency virus (HIV) to control virus production. Human-Chinese hamster ovary hybrid cell clones were used to probe for human chromosomes involved in regulating HIV gene expression. DNA transfection experiments showed that 4 of 18 clones had high levels of HIV gene expression measured by both extracellular virus production and transactivation of the HIV long terminal repeat in the presence of the trans-activator (tat) gene. Karyotype analyses revealed a 94% concordance (17/18) between human chromosome 12 and HIV gene expression. Other chromosomes had an 11 to 72% concordance with virus production. 相似文献
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Bard J Zhelkovsky AM Helmling S Earnest TN Moore CL Bohm A 《Science (New York, N.Y.)》2000,289(5483):1346-1349
Polyadenylate [poly(A)] polymerase (PAP) catalyzes the addition of a polyadenosine tail to almost all eukaryotic messenger RNAs (mRNAs). The crystal structure of the PAP from Saccharomyces cerevisiae (Pap1) has been solved to 2.6 angstroms, both alone and in complex with 3'-deoxyadenosine triphosphate (3'-dATP). Like other nucleic acid polymerases, Pap1 is composed of three domains that encircle the active site. The arrangement of these domains, however, is quite different from that seen in polymerases that use a template to select and position their incoming nucleotides. The first two domains are functionally analogous to polymerase palm and fingers domains. The third domain is attached to the fingers domain and is known to interact with the single-stranded RNA primer. In the nucleotide complex, two molecules of 3'-dATP are bound to Pap1. One occupies the position of the incoming base, prior to its addition to the mRNA chain. The other is believed to occupy the position of the 3' end of the mRNA primer. 相似文献
89.
90.
Total carbon and nitrogen abundances were determined by using combustion-gas chromatographic techlniques. Weighited mean analyses for butlk fines were 225 and 140 ppm total carbon and 150 anid 100 ppm total nitrogen. Total carbon in fine breccia was 230 ppm; in coarse breccia, 100 ppmn; in fine-grained rock, 70 ppm; and in mediumn-grained rock, 64 ppm. The finest sieved fraction had the highest carbon content. Total nitrogen in fine breccia was 125 ppm; in coarse breccia, 100 ppm; in fine-grained rock, 115 ppm; and in medium-grained rock, 30 ppm. The total carbon and nitrogen finies appeat to be mixtuires of indigenous lunar material togetheer with meteoritic and solar wind components. 相似文献