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G. H. Werner 《Cellular and molecular life sciences : CMLS》1957,13(8):318-319
Résumé La purification préalable, par le fluorocarbone, d'adénovirus (types 3, 4, 5 et 7) servant à l'immunisation de lapins, prévient
la formation dans le sérum de ces derniers d'anticorps fixateurs de complément, réagissant de manière non spécifique avec
les constituants des cultures de cellules dans lesquelles les virus ont été propagés.
Cette méthode ne permet cependant pas d'obtenir des anticorps qui réagissent de manière spécifique de type avec les adénovirus,
dans la réaction de déviation du complément.
相似文献
17.
I Farnan P J Grandinetti J H Baltisberger J F Stebbins U Werner M A Eastman A Pines 《Nature》1992,358(6381):31-35
Local order in silicate glasses has been observed by many experimental techniques to be similar to that in crystalline materials. Details of the intermediate-range order are more elusive, but essential for understanding the lack of long-range symmetry in glasses and the effect of composition on glass structure. Two-dimensional 17O dynamic-angle-spinning nuclear magnetic resonance experiments reveal intermediate-range order in the distribution of inter-tetrahedral (Si-O-Si) bond angles and a high degree of order in the disposition of oxygen atoms around the network-modifying cations. 相似文献
18.
Hauber E van Gasselt S Ivanov B Werner S Head JW Neukum G Jaumann R Greeley R Mitchell KL Muller P;HRSC Co-Investigator Team 《Nature》2005,434(7031):356-361
The majority of volcanic products on Mars are thought to be mafic and effusive. Explosive eruptions of basic to ultrabasic chemistry are expected to be common, but evidence for them is rare and mostly confined to very old surface features. Here we present new image and topographic data from the High Resolution Stereo Camera that reveal previously unknown traces of an explosive eruption at 30 degrees N and 149 degrees E on the northwestern flank of the shield volcano Hecates Tholus. The eruption created a large, 10-km-diameter caldera approximately 350 million years ago. We interpret these observations to mean that large-scale explosive volcanism on Mars was not confined to the planet's early evolution. We also show that glacial deposits partly fill the caldera and an adjacent depression. Their age, derived from crater counts, is about 5 to 24 million years. Climate models predict that near-surface ice is not stable at mid-latitudes today, assuming a thermo-dynamic steady state. Therefore, the discovery of very young glacial features at Hecates Tholus suggests recent climate changes. We show that the absolute ages of these very recent glacial deposits correspond very well to a period of increased obliquity of the planet's rotational axis. 相似文献
19.
Evidence from the Mars Express High Resolution Stereo Camera for a frozen sea close to Mars' equator
Murray JB Muller JP Neukum G Werner SC van Gasselt S Hauber E Markiewicz WJ Head JW Foing BH Page D Mitchell KL Portyankina G;HRSC Co-Investigator Team 《Nature》2005,434(7031):352-356
It is thought that the Cerberus Fossae fissures on Mars were the source of both lava and water floods two to ten million years ago. Evidence for the resulting lava plains has been identified in eastern Elysium, but seas and lakes from these fissures and previous water flooding events were presumed to have evaporated and sublimed away. Here we present High Resolution Stereo Camera images from the European Space Agency Mars Express spacecraft that indicate that such lakes may still exist. We infer that the evidence is consistent with a frozen body of water, with surface pack-ice, around 5 degrees north latitude and 150 degrees east longitude in southern Elysium. The frozen lake measures about 800 x 900 km in lateral extent and may be up to 45 metres deep--similar in size and depth to the North Sea. From crater counts, we determined its age to be 5 +/- 2 million years old. If our interpretation is confirmed, this is a place that might preserve evidence of primitive life, if it has ever developed on Mars. 相似文献
20.
Head JW Neukum G Jaumann R Hiesinger H Hauber E Carr M Masson P Foing B Hoffmann H Kreslavsky M Werner S Milkovich S van Gasselt S;HRSC Co-Investigator Team 《Nature》2005,434(7031):346-351
Images from the Mars Express HRSC (High-Resolution Stereo Camera) of debris aprons at the base of massifs in eastern Hellas reveal numerous concentrically ridged lobate and pitted features and related evidence of extremely ice-rich glacier-like viscous flow and sublimation. Together with new evidence for recent ice-rich rock glaciers at the base of the Olympus Mons scarp superposed on larger Late Amazonian debris-covered piedmont glaciers, we interpret these deposits as evidence for geologically recent and recurring glacial activity in tropical and mid-latitude regions of Mars during periods of increased spin-axis obliquity when polar ice was mobilized and redeposited in microenvironments at lower latitudes. The data indicate that abundant residual ice probably remains in these deposits and that these records of geologically recent climate changes are accessible to future automated and human surface exploration. 相似文献