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11.
Christlieb N Bessell MS Beers TC Gustafsson B Korn A Barklem PS Karlsson T Mizuno-Wiedner M Rossi S 《Nature》2002,419(6910):904-906
The chemical composition of the most metal-deficient stars largely reflects the composition of the gas from which they formed. These old stars provide crucial clues to the star formation history and the synthesis of chemical elements in the early Universe. They are the local relics of epochs otherwise observable only at very high redshifts; if totally metal-free ('population III') stars could be found, this would allow the direct study of the pristine gas from the Big Bang. Earlier searches for such stars found none with an iron abundance less than 1/10,000 that of the Sun, leading to the suggestion that low-mass stars could form from clouds above a critical iron abundance. Here we report the discovery of a low-mass star with an iron abundance as low as 1/200,000 of the solar value. This discovery suggests that population III stars could still exist--that is, that the first generation of stars also contained long-lived low-mass objects. The previous failure to find them may be an observational selection effect. 相似文献
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Chronic treatment with various drugs reduced the increase in arterial blood pressure, the ventricular hypertrophy and the thickening of pulmonary arterial and arteriolar walls. 相似文献
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G. Rossi V. Coiro L. Camellini D. Pignatti C. Davoli B. Lari R. Volpi P. Chiodera 《Cellular and molecular life sciences : CMLS》1985,41(12):1573-1574
Summary In order to establish whether thyrotropin-releasing hormone (TRH) inhibits lysine-vasopressin (LVP)-induced growth hormone (GH) release, six normal men were tested with LVP alone or in combination with TRH. LVP strikingly increased serum GH levels; this response was not altered by TRH. These results indicated that in man TRH is not involved in the control of GH secretion in response to LVP. 相似文献
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P A Bernabei F C Agostino R Bezzini R Saccardi V Gattei V Santini M Casini P Rossi Ferrini 《Experientia》1988,44(3):245-247
A kinetic study was performed on leukemic blasts from patients with acute myeloid leukemia, separated into 2 subpopulations by a specific density gradient. The growth curve and the [3H]-thymidine uptake were simultaneously analyzed. While cumulative nucleotide uptake fitted with the growth kinetics in the low-density fraction, such a concordance was not found in the high-density subpopulation. That indicated the occurrence of simultaneous growth and loss in the high density fraction, which could not be evaluated by a simple numerical determination. 相似文献
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C. Crifò A. Oratore F. Rossi Fanelli C. Cangiano S. Equizi R. Strom 《Cellular and molecular life sciences : CMLS》1976,32(2):239-241
Summary The unesterified cholesterol content of plasma samples can be evaluated from the extent of inhibition of lucensomycin-induced hemolysis. The test measures, however, only the fraction of cholesterol which is available for interaction with lucensomycin, this availability being adversely affected by high phospholipid-cholesterol ratios. 相似文献
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Myonecrosis induced by scorpion venom 总被引:1,自引:0,他引:1
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