A homolog of Drosophila grainy head is essential for epidermal integrity in mice   总被引：1，自引：0，他引：1  

Ting SB  Caddy J  Hislop N  Wilanowski T  Auden A  Zhao LL  Ellis S  Kaur P  Uchida Y  Holleran WM  Elias PM  Cunningham JM  Jane SM 《Science (New York, N.Y.)》2005,308(5720):411-413

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Deep mantle cycling of oceanic crust: evidence from diamonds and their mineral inclusions   总被引：6，自引：0，他引：6  

Walter MJ  Kohn SC  Araujo D  Bulanova GP  Smith CB  Gaillou E  Wang J  Steele A  Shirey SB 《Science (New York, N.Y.)》2011,334(6052):54-57

A primary consequence of plate tectonics is that basaltic oceanic crust subducts with lithospheric slabs into the mantle. Seismological studies extend this process to the lower mantle, and geochemical observations indicate return of oceanic crust to the upper mantle in plumes. There has been no direct petrologic evidence, however, of the return of subducted oceanic crustal components from the lower mantle. We analyzed superdeep diamonds from Juina-5 kimberlite, Brazil, which host inclusions with compositions comprising the entire phase assemblage expected to crystallize from basalt under lower-mantle conditions. The inclusion mineralogies require exhumation from the lower to upper mantle. Because the diamond hosts have carbon isotope signatures consistent with surface-derived carbon, we conclude that the deep carbon cycle extends into the lower mantle.  相似文献   

Design and chemical synthesis of a homogeneous polymer-modified erythropoiesis protein     

Kochendoerfer GG  Chen SY  Mao F  Cressman S  Traviglia S  Shao H  Hunter CL  Low DW  Cagle EN  Carnevali M  Gueriguian V  Keogh PJ  Porter H  Stratton SM  Wiedeke MC  Wilken J  Tang J  Levy JJ  Miranda LP  Crnogorac MM  Kalbag S  Botti P  Schindler-Horvat J  Savatski L  Adamson JW  Kung A  Kent SB  Bradburne JA 《Science (New York, N.Y.)》2003,299(5608):884-887

We report the design and total chemical synthesis of "synthetic erythropoiesis protein" (SEP), a 51-kilodalton protein-polymer construct consisting of a 166-amino-acid polypeptide chain and two covalently attached, branched, and monodisperse polymer moieties that are negatively charged. The ability to control the chemistry allowed us to synthesize a macromolecule of precisely defined covalent structure. SEP was homogeneous as shown by high-resolution analytical techniques, with a mass of 50,825 +/-10 daltons by electrospray mass spectrometry, and with a pI of 5.0. In cell and animal assays for erythropoiesis, SEP displayed potent biological activity and had significantly prolonged duration of action in vivo. These chemical methods are a powerful tool in the rational design of protein constructs with potential therapeutic applications.  相似文献   

Zond 5: sketches and guesses     

Kramer SB 《Science (New York, N.Y.)》1968,162(3859):1223

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Communication in neuronal networks     

Laughlin SB  Sejnowski TJ 《Science (New York, N.Y.)》2003,301(5641):1870-1874

Brains perform with remarkable efficiency, are capable of prodigious computation, and are marvels of communication. We are beginning to understand some of the geometric, biophysical, and energy constraints that have governed the evolution of cortical networks. To operate efficiently within these constraints, nature has optimized the structure and function of cortical networks with design principles similar to those used in electronic networks. The brain also exploits the adaptability of biological systems to reconfigure in response to changing needs.  相似文献   

Genetics. FDA races in wrong direction     

Haga SB  Venter JC 《Science (New York, N.Y.)》2003,301(5632):466

Despite recent genetic evidence and the promise of individualized medicine, there is a continuing interest in using self-identified categories of race and ethnicity as variables in scientific and medical research. The U.S. Food and Drug Administration recently proposed a standardized approach for the collection of race and ethnicity data in clinical trials. We believe that this move fails to acknowledge new scientific data and recommend that relevant data from individuals be collected and used rather than broad group statistics. We also encourage that increased funding be committed to this important issue.  相似文献   

Gibberellins: a phytohormonal basis for heterosis in maize     

Rood SB  Buzzell RI  Mander LN  Pearce D  Pharis RP 《Science (New York, N.Y.)》1988,241(4870):1216-1218

Four commercially important maize parental inbreds and their 12 F(1) hybrids were studied to investigate the role of the phytohormone gibberellin (GA) in the regulation of heterosis (hybrid vigor). All hybrids grew faster than any inbred. In contrast, all inbreds showed a greater promotion of shoot growth after the exogenous application of GA(3). Concentrations of endogenous GA(1), the biological effector for shoot growth in maize, and GA(19), a precursor of GA(1), were measured in apical meristematic shoot cylinders for three of the inbreds and their hybrids by gas chromatography-mass spectrometry with selected ion monitoring; deuterated GAs were used as quantitative internal standards. In 34 of 36 comparisons, hybrids contained higher concentrations of endogenous GAs than their parental inbreds. Preferential growth acceleration of the inbreds by exogenous GA(3) indicates that a deficiency of endogenous GA limits the growth of the inbreds and is thus a cause of inbreeding depression. Conversely, the increased endogenous concentration of GA in the hybrids could provide a phytohormonal basis for heterosis for shoot growth.  相似文献   

The Climatological Significance of a Doubling of Earth's Atmospheric Carbon Dioxide Concentration     

Idso SB 《Science (New York, N.Y.)》1980,207(4438):1462-1463

The mean global increase in thermal radiation received at the surface of the earth as a consequence of a doubling of the atmospheric carbon dioxide content is calculated to be 2.28 watts per square meter. Multiplying this forcing function by the atmosphere's surface air temperature response function, which has recently been determined by three independent experimental analyses to have a mean global value of 0.113 K per watt per square meter, yields a value of 相似文献   

Cool water: demonstration of a clean and efficient new coal technology     

Spencer DF  Alpert SB  Gilman HH 《Science (New York, N.Y.)》1986,232(4750):609-612

Cool Water, the world's first commercial-scale, integrated coal gasification combined cycle power plant, has been operating successfully since May 1984 near Barstow, California. The 100-megawatt plant, which was completed ahead of schedule and under budget, is probably the cleanest coal-fired power generating facility now in commercial operation. An ongoing demonstration program at Cool Water shows that future baseload power plants that use this technology can be built modularly in increments of a few hundred megawatts and compete economically with much larger, conventional coal-fired power plants equipped for flue gas desulfurization.  相似文献   

Surface albedo and desertification     

Jackson RD  Idso SB  Otterman J 《Science (New York, N.Y.)》1975,189(4207):1012-1015

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