A modern approach to the isolation and characterization of L-ascorbic acid (vitamin C)     

J P Scannell  H A Ax  W Morris 《Journal of agricultural and food chemistry》1974,22(3):538-539

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Small interfering RNA-induced transcriptional gene silencing in human cells   总被引：1，自引：0，他引：1  

Morris KV  Chan SW  Jacobsen SE  Looney DJ 《Science (New York, N.Y.)》2004,305(5688):1289-1292

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Burgess shale faunas and the cambrian explosion     

Morris SC 《Science (New York, N.Y.)》1989,246(4928):339-346

Soft-bodied marine faunas from the Lower and Middle Cambrian, exemplified by the Burgess Shale of British Columbia, are a key component in understanding the major adaptive radiations at the beginning of the Phanerozoic ("Cambrian explosion"). These faunas have a widespread distribution, and many taxa have pronounced longevity. Among the components appear to be survivors of the preceding Ediacaran assemblages and a suite of bizarre forms that give unexpected insights into morphological diversification. Microevolutionary processes, however, seem adequate to account for this radiation, and the macroevolutionary patterns that set the seal on Phanerozoic life are contingent on random extinctions. They weeded out the morphological spectrum and permitted rediversification among surviving clades. Although the predictability of which clades will play in successive acts of the Phanerozoic theater is low, at least the outlines of the underlying ecological plot are already clear from the opening of the drama.  相似文献   

Coupled ferric oxides and sulfates on the Martian surface     

Bibring JP  Arvidson RE  Gendrin A  Gondet B  Langevin Y  Le Mouelic S  Mangold N  Morris RV  Mustard JF  Poulet F  Quantin C  Sotin C 《Science (New York, N.Y.)》2007,317(5842):1206-1210

The Mars Exploration Rover (MER), Opportunity, showed that layered sulfate deposits in Meridiani Planum formed during a period of rising acidic ground water. Crystalline hematite spherules formed in the deposits as a consequence of aqueous alteration and were concentrated on the surface as a lag deposit as wind eroded the softer sulfate rocks. On the basis of Mars Express Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité (OMEGA) orbital data, we demonstrate that crystalline hematite deposits are associated with layered sulfates in other areas on Mars, implying that Meridiani-like ground water systems were indeed widespread and representative of an extensive acid sulfate aqueous system.  相似文献   

Electrical Resistivity and Stoichiometry of CaxC60 and SrxC60 Films     

Haddon RC  Kochanski GP  Hebard AF  Fiory AT  Morris RC 《Science (New York, N.Y.)》1992,258(5088):1636-1638

The temperature- and concentration-dependent resistivities of annealed CaxC(60) and SrxC(60) films were measured near room temperature. Resistivity minima were observed at x = 2 and 5. The resistivities of these films were rho(min) approximately 1 ohm-centimeter for x = 2 and rho(min) approximately 10(-2) ohm-centimeter for x = 5. This latter value is comparable to the resistivities found in similar experiments on K(3)C(60) films. There is a maximum in the resistivity between x = 2 and 3, and another at x approximately 7. The conductivity is activated over the whole range of compositions, and the activation energy scales with the logarithm of the resistivity. The results suggest that the conductivity and superconductivity observed in Ca(5)C(60) are associated with the population of bands derived from the t(1g) level of C(6O).  相似文献   

Circadian periodicity in susceptibility to lidocaine hydrochloride   总被引：1，自引：0，他引：1  

E F Lutsch  R W Morris 《Science (New York, N.Y.)》1967,156(771):100-102

Separate groups of mice standardized in an alternating 12-hour-light,12-hour-dark regimen were treated with lidocaine hydrochloride every 3 hours over a 24-hour period. The results indicate a quantitative circadian periodicity with maximal convulsant activity at 2100 hours which was approximately a fourteen fold increase over the values observed at 1500 hours.  相似文献   

Mitochondrial polyriboadenylate polymerase: relative lack of activity in hepatomas   总被引：3，自引：0，他引：3  

S T Jacob  D G Schindler  H P Morris 《Science (New York, N.Y.)》1972,178(61):639-640

An enzyme that polymerizes adenylate residues from adenosine triphosphate was prepared from rat liver mitochondria and compared to similar preparations from the mitochondria of three hepatomas. Enzyme activity in the hepatomas was only 1 to 2 percent of that in normal liver.  相似文献   

Specific inhibition of nuclear RNA polymerase II by alpha-amanitin   总被引：75，自引：0，他引：75  

T J Lindell  F Weinberg  P W Morris  R G Roeder  W J Rutter 《Science (New York, N.Y.)》1970,170(956):447-449

alpha-Amanitin, a toxic substance from the mushroom Amanita phalloides, is a potent inhibitor of DNA-dependent RNA polymerase II (the nucleoplasmic form) from sea urchin, rat liver, and calf thymus. This compound exerts no effect on the activity of polymerase I (nucleolar form) or polymerase III (also nucleoplasmic). The inhibition is due to a specific interaction with polymerase II or with a complex of DNA and polymerase II.  相似文献   

Undergraduate research. Genomics Education Partnership     

Lopatto D  Alvarez C  Barnard D  Chandrasekaran C  Chung HM  Du C  Eckdahl T  Goodman AL  Hauser C  Jones CJ  Kopp OR  Kuleck GA  McNeil G  Morris R  Myka JL  Nagengast A  Overvoorde PJ  Poet JL  Reed K  Regisford G  Revie D  Rosenwald A  Saville K  Shaw M  Skuse GR  Smith C  Smith M  Spratt M  Stamm J  Thompson JS  Wilson BA  Witkowski C  Youngblom J  Leung W  Shaffer CD  Buhler J  Mardis E  Elgin SC 《Science (New York, N.Y.)》2008,322(5902):684-685

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The surface of Mars: there view from the viking 1 lander     

Mutch TA  Binder AB  Huck FO  Levinthal EC  Liebes S  Morris EC  Patterson WR  Pollack JB  Sagan C  Taylor GR 《Science (New York, N.Y.)》1976,193(4255):791-801

The first photographs ever returned from the surface of Mars were obtained by two facsimile cameras aboard the Viking 1 lander, including black-and-white and color, 0.12 degrees and 0.04 degrees resolution, and monoscopic and stereoscopic images. The surface, on the western slopes of Chtyse Planitia, is a boulder-strewn deeply reddish desert, with distant eminences-some of which may be the rims of impact craters-surmounted by a pink sky. Both impact and aeolian processes are evident. After dissipation of a small dust cloud stirred by the landing maneuvers, no subsequent signs of movement were detected on the landscape, and nothing has been observed that is indicative of macroscopic biology at this time and place.  相似文献