Diurnal changes in the partial pressure of carbon dioxide in coral reef water     

Kayanne H  Suzuki A  Saito H 《Science (New York, N.Y.)》1995,269(5221):214-216

Coral reefs are considered to be a source of atmospheric carbon dioxide because of their high calcium carbonate production and low net primary production. This was tested by direct measurement of diurnal changes in the partial pressure of carbon dioxide (Pco(co2)) in reef waters during two 3-day periods, one in March 1993 and one in March 1994, on Shiraho reef of the Ryukyu Islands, Japan. Although the Pco(co2) values in reef waters exhibited large diurnal changes ranging from 160 to 520 microatmospheres, they indicate that the reef flat area is a net sink for atmospheric carbon dioxide. This suggests that the net organic production rate of the reef community exceeded its calcium carbonate production rate during the observation periods.  相似文献   

Arctic paleo-oceanography in late cenozoic time     

Hunkins K  Bé AW  Opdyke N  Saito T  Herman Y 《Science (New York, N.Y.)》1971,174(4012):962-963

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Chromosomal locations of the murine T-cell receptor alpha-chain gene and the T-cell gamma gene   总被引：11，自引：0，他引：11  

D M Kranz  H Saito  C M Disteche  K Swisshelm  D Pravtcheva  F H Ruddle  H N Eisen  S Tonegawa 《Science (New York, N.Y.)》1985,227(4689):941-945

Two independent methods were used to identify the mouse chromosomes on which are located two families of immunoglobulin (Ig)-like genes that are rearranged and expressed in T lymphocytes. The genes coding for the alpha subunit of T-cell receptors are on chromosome 14 and the gamma genes, whose function is yet to be determined, are on chromosome 13. Since genes for the T-cell receptor beta chain were previously shown to be on mouse chromosome 6, all three of the Ig-like multigene families expressed and rearranged in T cells are located on different chromosomes, just as are the B-cell multigene families for the Ig heavy chain, and the Ig kappa and lambda light chains. The findings do not support earlier contentions that genes for T-cell receptors are linked to the Ig heavy chain locus (mouse chromosome 12) or to the major histocompatibility complex (mouse chromosome 17).  相似文献   

Tertiary sediment from the East pacific rise     

Burckle LH  Ewing J  Saito T  Leyden R 《Science (New York, N.Y.)》1967,157(3788):537-540

More than 50 cores ranging in age from Pliocene to Lower Miocene have been recovered from the East Pacific Rise. Near the crestal regions the sediment cover is thin or lacking, and only Pleistocene sediments were recovered. On the flanks, the sediment thickness increases and pre-Pleistocene sediments are encountered. This pattern of increasing age and increasing sediment thickness away from the axis of the rise is in agreement with that predicted for spreading of the ocean floor.  相似文献   

Discovery of a Jupiter/Saturn analog with gravitational microlensing     

Gaudi BS  Bennett DP  Udalski A  Gould A  Christie GW  Maoz D  Dong S  McCormick J  Szymanski MK  Tristram PJ  Nikolaev S  Paczynski B  Kubiak M  Pietrzynski G  Soszynski I  Szewczyk O  Ulaczyk K  Wyrzykowski L;OGLE Collaboration  Depoy DL  Han C  Kaspi S  Lee CU  Mallia F  Natusch T  Pogge RW  Park BG;MuFUN Collaboration  Abe F  Bond IA  Botzler CS  Fukui A  Hearnshaw JB  Itow Y  Kamiya K  Korpela AV  Kilmartin PM  Lin W  Masuda K  Matsubara Y  Motomura M  Muraki Y  Nakamura S  Okumura T  Ohnishi K  Rattenbury NJ  Sako T  Saito T  Sato S 《Science (New York, N.Y.)》2008,319(5865):927-930

Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of approximately 0.71 and approximately 0.27 times the mass of Jupiter and orbital separations of approximately 2.3 and approximately 4.6 astronomical units orbiting a primary star of mass approximately 0.50 solar mass at a distance of approximately 1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.  相似文献   

High-density electron anions in a nanoporous single crystal: [Ca24Al28O64]4+(4e-)   总被引：1，自引：0，他引：1  

Matsuishi S  Toda Y  Miyakawa M  Hayashi K  Kamiya T  Hirano M  Tanaka I  Hosono H 《Science (New York, N.Y.)》2003,301(5633):626-629

We removed approximately 100% of clathrated oxygen ions from the crystallographic cages in a single crystal of 12CaO.7Al2O3, leading to the formation of high-density (approximately 2 x 10(21) cm-3) electrons highly localized in the cages. The resulting electron forms a structure that we interpret as an F+ center and migrates throughout the crystal by hopping to a neighboring cage with conductivity approximately 100 siemens per centimeter, demonstrating that the encaged electron behaves as an anion. The electron anions couple antiferromagnetically with each other, forming a diamagnetic pair or singlet bipolaron. The resulting [Ca24Al28O64]4+(4e-) may be regarded as a thermally and chemically stable single crystalline "electride."  相似文献   

GaN photonic-crystal surface-emitting laser at blue-violet wavelengths     

Matsubara H  Yoshimoto S  Saito H  Jianglin Y  Tanaka Y  Noda S 《Science (New York, N.Y.)》2008,319(5862):445-447

Shorter-wavelength surface-emitting laser sources are important for a variety of fields, including photonics, information processing, and biology. We report on the creation of a current-driven blue-violet photonic-crystal surface-emitting laser. We have developed a fabrication method, named "air holes retained over growth," in order to construct a two-dimensional gallium nitride (GaN)/air photonic-crystal structure. The resulting periodic structure has a photonic-crystal band-edge effect sufficient for the successful operation of a current-injection surface-emitting laser. This represents an important step in the development of laser sources that could be focused to a size much less than the wavelength and be integrated two-dimensionally at such short wavelengths.  相似文献   

A four-base paired genetic helix with expanded size     

Liu H  Gao J  Lynch SR  Saito YD  Maynard L  Kool ET 《Science (New York, N.Y.)》2003,302(5646):868-871

We describe a new molecular class of genetic-pairing system that has a native DNA backbone but has all four base pairs replaced by new, larger pairs. The base pairs include size-expanded analogs of thymine and of adenine, both extended by the width of a benzene ring (2.4 A). The expanded-diameter double helices are more thermodynamically stable than the Watson-Crick helix, likely because of enhanced base stacking. Structural data confirm a right-handed, double-stranded, and base-paired helical form. Because of the larger base size, all the pairs of this helical system are fluorescent, which suggests practical applications in detection of natural DNA and RNA. Our findings establish that there is no apparent structural or thermodynamic prohibition against genetic systems having sizes different from the natural one.  相似文献   

Oxygen isotopic compositions of asteroidal materials returned from Itokawa by the Hayabusa mission     

Yurimoto H  Abe K  Abe M  Ebihara M  Fujimura A  Hashiguchi M  Hashizume K  Ireland TR  Itoh S  Katayama J  Kato C  Kawaguchi J  Kawasaki N  Kitajima F  Kobayashi S  Meike T  Mukai T  Nagao K  Nakamura T  Naraoka H  Noguchi T  Okazaki R  Park C  Sakamoto N  Seto Y  Takei M  Tsuchiyama A  Uesugi M  Wakaki S  Yada T  Yamamoto K  Yoshikawa M  Zolensky ME 《Science (New York, N.Y.)》2011,333(6046):1116-1119

Meteorite studies suggest that each solar system object has a unique oxygen isotopic composition. Chondrites, the most primitive of meteorites, have been believed to be derived from asteroids, but oxygen isotopic compositions of asteroids themselves have not been established. We measured, using secondary ion mass spectrometry, oxygen isotopic compositions of rock particles from asteroid 25143 Itokawa returned by the Hayabusa spacecraft. Compositions of the particles are depleted in (16)O relative to terrestrial materials and indicate that Itokawa, an S-type asteroid, is one of the sources of the LL or L group of equilibrated ordinary chondrites. This is a direct oxygen-isotope link between chondrites and their parent asteroid.  相似文献   

Dynamics of Nrf2 and Keap1 in ARE-mediated NQO1 expression by wasabi 6-(methylsulfinyl)hexyl isothiocyanate     

Hou DX  Korenori Y  Tanigawa S  Yamada-Kato T  Nagai M  He X  He J 《Journal of agricultural and food chemistry》2011,59(22):11975-11982

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