Nightglow in the upper atmosphere of Mars and implications for atmospheric transport   总被引：1，自引：0，他引：1  

Bertaux JL  Leblanc F  Perrier S  Quemerais E  Korablev O  Dimarellis E  Reberac A  Forget F  Simon PC  Stern SA  Sandel B;SPICAM Team 《Science (New York, N.Y.)》2005,307(5709):566-569

We detected light emissions in the nightside martian atmosphere with the SPICAM (spectroscopy for the investigation of the characteristics of the atmosphere of Mars) ultraviolet (UV) spectrometer on board the Mars Express. The UV spectrum of this nightglow is composed of hydrogen Lyman alpha emission (121.6 nanometers) and the gamma and delta bands of nitric oxide (NO) (190 to 270 nanometers) produced when N and O atoms combine to produce the NO molecule. N and O atoms are produced by extreme UV photodissociation of O2, CO2, and N2 in the dayside upper atmosphere and transported to the night side. The NO emission is brightest in the winter south polar night because of continuous downward transport of air in this region at night during winter and because of freezing at ground level.  相似文献   

ABAD directly links Abeta to mitochondrial toxicity in Alzheimer's disease     

Lustbader JW  Cirilli M  Lin C  Xu HW  Takuma K  Wang N  Caspersen C  Chen X  Pollak S  Chaney M  Trinchese F  Liu S  Gunn-Moore F  Lue LF  Walker DG  Kuppusamy P  Zewier ZL  Arancio O  Stern D  Yan SS  Wu H 《Science (New York, N.Y.)》2004,304(5669):448-452

Mitochondrial dysfunction is a hallmark of beta-amyloid (Abeta)-induced neuronal toxicity in Alzheimer's disease (AD). Here, we demonstrate that Abeta-binding alcohol dehydrogenase (ABAD) is a direct molecular link from Abeta to mitochondrial toxicity. Abeta interacts with ABAD in the mitochondria of AD patients and transgenic mice. The crystal structure of Abeta-bound ABAD shows substantial deformation of the active site that prevents nicotinamide adenine dinucleotide (NAD) binding. An ABAD peptide specifically inhibits ABAD-Abeta interaction and suppresses Abeta-induced apoptosis and free-radical generation in neurons. Transgenic mice overexpressing ABAD in an Abeta-rich environment manifest exaggerated neuronal oxidative stress and impaired memory. These data suggest that the ABAD-Abeta interaction may be a therapeutic target in AD.  相似文献   

Construction of a novel oncogene based on synthetic sequences encoding epidermal growth factor   总被引：20，自引：0，他引：20  

D F Stern  D L Hare  M A Cecchini  R A Weinberg 《Science (New York, N.Y.)》1987,235(4786):321-324

The autocrine model postulates that constitutive release of a mitogenic growth factor can lead to uncontrolled proliferation and cell transformation. A synthetic polynucleotide encoding epidermal growth factor conferred a tumorigenic phenotype on cells. These cells were transformed through the action of an autocrine circuit having an extracellular component.  相似文献   

Inhibition of collagen fibril formation in vitro and subsequent cross-linking by glucose   总被引：2，自引：0，他引：2  

Y H Lien  R Stern  J C Fu  R C Siegel 《Science (New York, N.Y.)》1984,225(4669):1489-1491

Glucose inhibits collagen fibril formation in vitro. A linear dose response was observed, with half-maximum inhibition of fibril formation occurring at 50 mM glucose. Nonfibrillar collagen cannot be cross-linked by lysyl oxidase, an enzyme that catalyzes the initial cross-linking reaction. The degree of decreased fibril formation correlated with the loss of ability of the collagen to serve as a substrate for lysyl oxidase. Collagen that is not cross-linked is unstable and more susceptible to collagenolytic attack. Interference with collagen cross-linking and more rapid degradation may explain the decreased amounts of interstitial collagen and the poor healing of wounds associated with diabetes mellitus.  相似文献   

Jupiter cloud composition, stratification, convection, and wave motion: a view from new horizons     

Reuter DC  Simon-Miller AA  Lunsford A  Baines KH  Cheng AF  Jennings DE  Olkin CB  Spencer JR  Stern SA  Weaver HA  Young LA 《Science (New York, N.Y.)》2007,318(5848):223-225

Several observations of Jupiter's atmosphere made by instruments on the New Horizons spacecraft have implications for the stability and dynamics of Jupiter's weather layer. Mesoscale waves, first seen by Voyager, have been observed at a spatial resolution of 11 to 45 kilometers. These waves have a 300-kilometer wavelength and phase velocities greater than the local zonal flow by 100 meters per second, much higher than predicted by models. Additionally, infrared spectral measurements over five successive Jupiter rotations at spatial resolutions of 200 to 140 kilometers have shown the development of transient ammonia ice clouds (lifetimes of 40 hours or less) in regions of strong atmospheric upwelling. Both of these phenomena serve as probes of atmospheric dynamics below the visible cloud tops.  相似文献   

Strong electrical currents leave the primitive streak of chick embryos   总被引：6，自引：0，他引：6  

L F Jaffe  C D Stern 《Science (New York, N.Y.)》1979,206(4418):569-571

The electrical fields above chick embryos were explored with a vibrating probe. These fields indicate that steady currents with exit densities of the order of 100 microamperes per square centimeter leave the whole streak and return elsewhere through the epiblast. The epicenter of these strong exit currents lies near Hensen's node. They are probably pumped into the intraembryonic space by the epiblast and then leak out of the streak because it is a zone of junctional disruption.  相似文献   

Natural selection and developmental constraints in the evolution of allometries     

Frankino WA  Zwaan BJ  Stern DL  Brakefield PM 《Science (New York, N.Y.)》2005,307(5710):718-720

In animals, scaling relationships between appendages and body size exhibit high interspecific variation but low intraspecific variation. This pattern could result from natural selection for specific allometries or from developmental constraints on patterns of differential growth. We performed artificial selection on the allometry between forewing area and body size in a butterfly to test for developmental constraints, and then used the resultant increased range of phenotypic variation to quantify natural selection on the scaling relationship. Our results show that the short-term evolution of allometries is not limited by developmental constraints. Instead, scaling relationships are shaped by strong natural selection.  相似文献   

ON THE NATURE OF THE AGENT CAUSING LEUCOSIS IN FOWLS     

Stern KG  Kirschbaum A 《Science (New York, N.Y.)》1939,89(2322):610-611

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EQUIPMENT NEWS     

Stern J 《Science (New York, N.Y.)》1957,125(3245):460-462

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Book reviews     

Waldichuk  Michael  Stern  Arthur C.  Çotuk  Yavuz  Humphrey  G. F.  Astolfi  Emilio  Ormrod  D. P.  Preining  O.  Benarie  Michel  Viraraghavan  T. 《Water, air, and soil pollution》1983,20(4):465-475

Water, Air, & Soil Pollution -  相似文献