Catálogo de publicaciones - revistas

<jats:p>A compound that targets the Wnt signaling pathway in cancer moves into therapeutic trials, 30 years after Wnt was discovered.</jats:p>

<jats:p>A gel-on-brush model for the mucosal surfaces in the human airways helps to explain how common airway diseases arise.</jats:p>

<jats:p>Cancer cells may cope with oxidative stress through the glycosylation of a metabolic enzyme.</jats:p>

<jats:title>Stellar Explosions</jats:title> <jats:p> Stars that are born with masses greater than eight times that of the Sun end their lives in luminous explosions known as supernovae. Over the past decade, access to improved sky surveys has revealed rare types of supernovae that are much more luminous than any of those that were known before. <jats:bold>Gal-Yam</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="927" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1203601">927</jats:related-article> ) reviews these superluminous events and groups them into three classes that share common observational and physical characteristics. Gamma-ray bursts are another type of extreme explosive events related to the death of massive stars, which occur once per day somewhere in the universe and produce short-lived bursts of gamma-ray light. <jats:bold>Gehrels and Mészáros</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="932" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1216793">932</jats:related-article> ) review what has been learned about these events since the launch of NASA's Swift (2004) and Fermi (2008) satellites. The current interpretation is that gamma-ray bursts are related to the formation of black holes. Type Ia supernovae are used as cosmological distance indicators. They are thought to be the result of the thermonuclear explosion of white dwarf stars in binary systems, but the nature of the stellar companion to the white dwarf is still debated. <jats:bold> Dilday <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="942" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1219164">942</jats:related-article> ) report high-resolution spectroscopy of the supernova PTF 11kx, which was detected on 26 January 2011 by the Palomar Transient Factory survey. The data suggest a red giant star companion whose material got transferred to the white dwarf. </jats:p>

<jats:title>Stellar Explosions</jats:title> <jats:p> Stars that are born with masses greater than eight times that of the Sun end their lives in luminous explosions known as supernovae. Over the past decade, access to improved sky surveys has revealed rare types of supernovae that are much more luminous than any of those that were known before. <jats:bold>Gal-Yam</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="927" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1203601">927</jats:related-article> ) reviews these superluminous events and groups them into three classes that share common observational and physical characteristics. Gamma-ray bursts are another type of extreme explosive events related to the death of massive stars, which occur once per day somewhere in the universe and produce short-lived bursts of gamma-ray light. <jats:bold>Gehrels and Mészáros</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="932" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1216793">932</jats:related-article> ) review what has been learned about these events since the launch of NASA's Swift (2004) and Fermi (2008) satellites. The current interpretation is that gamma-ray bursts are related to the formation of black holes. Type Ia supernovae are used as cosmological distance indicators. They are thought to be the result of the thermonuclear explosion of white dwarf stars in binary systems, but the nature of the stellar companion to the white dwarf is still debated. <jats:bold> Dilday <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="942" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1219164">942</jats:related-article> ) report high-resolution spectroscopy of the supernova PTF 11kx, which was detected on 26 January 2011 by the Palomar Transient Factory survey. The data suggest a red giant star companion whose material got transferred to the white dwarf. </jats:p>

<jats:title>Sticky Mucus?</jats:title> <jats:p> Mucus—experienced, for example, in the form of a runny nose or productive cough—is one of the tools the body uses to expel or prevent the uptake of foreign matter. In a number of diseases, a failure of the normal mucus-control system leads to obstructions of the airways and respiratory problems. <jats:bold> Button <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="937" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1223012">937</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6097" page="924" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1227091"> <jats:bold>Dickey</jats:bold> </jats:related-article> ) examine the existing gel-on-liquid model, where the mucus is thought to sit on a watery periciliary layer around the beating lung cilia that has been used to explain the flow of mucus. A gel-on-brush model is proposed where the mucus sits on a brushlike periciliary layer. The key elements of this layer are membrane-tethered macromolecules that cause normal flow and clearance of mucus. When dehydrated, the interface is disrupted, preventing normal mucus motion. </jats:p>

<jats:title>Stellar Explosions</jats:title> <jats:p> Stars that are born with masses greater than eight times that of the Sun end their lives in luminous explosions known as supernovae. Over the past decade, access to improved sky surveys has revealed rare types of supernovae that are much more luminous than any of those that were known before. <jats:bold>Gal-Yam</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="927" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1203601">927</jats:related-article> ) reviews these superluminous events and groups them into three classes that share common observational and physical characteristics. Gamma-ray bursts are another type of extreme explosive events related to the death of massive stars, which occur once per day somewhere in the universe and produce short-lived bursts of gamma-ray light. <jats:bold>Gehrels and Mészáros</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="932" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1216793">932</jats:related-article> ) review what has been learned about these events since the launch of NASA's Swift (2004) and Fermi (2008) satellites. The current interpretation is that gamma-ray bursts are related to the formation of black holes. Type Ia supernovae are used as cosmological distance indicators. They are thought to be the result of the thermonuclear explosion of white dwarf stars in binary systems, but the nature of the stellar companion to the white dwarf is still debated. <jats:bold> Dilday <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="942" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1219164">942</jats:related-article> ) report high-resolution spectroscopy of the supernova PTF 11kx, which was detected on 26 January 2011 by the Palomar Transient Factory survey. The data suggest a red giant star companion whose material got transferred to the white dwarf. </jats:p>

<jats:title>Finger on the Pulsar</jats:title> <jats:p> Pulsars, the most commonly seen neutron stars, have been known for over four decades. They are rotating, dense stars with very strong magnetic fields, whose spectra have been understood as a superposition of continuum components of thermal and nonthermal origin. <jats:bold> Kargaltsev <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="946" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1221378">946</jats:related-article> ) now report the detection of absorption features in the x-ray spectrum of an ordinary radio pulsar. These features may be more common than was previously thought and may provide the opportunity to probe the environment and radiation physics of neutron stars. </jats:p>

<jats:title>Oscillating Black Hole</jats:title> <jats:p> The massive black holes that reside in the centers of galaxies can occasionally capture and tidally disrupt stars that wander too close. One such tidal disruption event was detected last year by the Swift satellite. Follow-up x-ray observations analyzed by <jats:bold> Reis <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="949" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1223940">949</jats:related-article> , published online 2 August; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6097" page="916" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1227083">McKinney</jats:related-article> </jats:bold> ) show quasi-periodic oscillations that suggest that an accretion disk formed around the black hole shortly after the tidal disruption event. This type of oscillation is commonly seen in the x-ray light from the much lighter black holes that result from the gravitational collapse of stars, but has been seen only once in a massive black hole residing in the center of a galaxy. </jats:p>

<jats:title>Metal Manipulation</jats:title> <jats:p> Reducing the grain size below 100 micrometers can vastly improve the properties of a metal. However, these nanocrystalline metals are not thermally stable; at elevated temperatures the grains will grow and merge. Alloying with a second metal to slow grain growth can slow down this process, which has shown some success on a trial-and-error basis. <jats:bold> Chookajorn <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="951" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1224737">951</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6097" page="921" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1226724"> <jats:bold>Weertman</jats:bold> </jats:related-article> ) now provide a theoretical framework to create stability maps to identify potential alloys with the greatest thermal stability. For tungsten, counterintuitively, the theory suggests that atoms with the largest size differential or lowest solubility are not the best alloying choice. Indeed, an alloy of tungsten and titanium was processed more easily than pure nanocrystalline tungsten and also showed better stability at high temperatures. </jats:p>