Catálogo de publicaciones - revistas

<jats:title>Allowing calcium to leak across a membrane</jats:title> <jats:p> Cells maintain a balance between calcium in the cytosol and calcium stored in organelles—too much stored calcium kills cells. Transmembrane Bax inhibitor motif (TMBIM) proteins form channels in organelle membranes that allow calcium to leak out. Chang <jats:italic>et al.</jats:italic> show that this calcium leak is pH-dependent. A bacterial homolog of TMBIM proteins converts between an open channel at low pH and a closed channel at high pH. Although the channel is open at low pH, calcium leakage is low because the inside of the channel remains at a neutral pH. Thus, at physiological pH, these channels will be in equilibrium between the open and closed states, so that excess calcium can leak through. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1131" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252043">1131</jats:related-article> </jats:p>

<jats:title>Electrical control of nuclear spin qubits</jats:title> <jats:p> Quantum bits of information (qubits) that are based on spins of atomic nuclei are an attractive option for quantum information processing. It can sometimes be tricky to manipulate these qubits using magnetic fields directly. Thiele <jats:italic>et al.</jats:italic> developed a technique for electrically controlling a nuclear spin qubit in the single-molecule magnet TbPc <jats:sub>2</jats:sub> . When they hit the qubit with a microwave pulse, the microwave's electric field generated effective magnetic fields much larger than those available previously. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1135" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1249802">1135</jats:related-article> </jats:p>

<jats:title>Monitoring water interfaces in motion</jats:title> <jats:p> Water behaves differently at interfaces—where it meets the air, or a solid surface—than it does in the middle of the liquid. Past laboratory studies of this phenomenon have mainly focused on still samples, despite the fact that in natural settings such as rivers and rain, the water moves along the surfaces. Lis <jats:italic>et al.</jats:italic> used a microfluidics apparatus and a spectroscopy technique called sum frequency generation to study the effects of flow on aqueous chemistry at silica and fluorite surfaces (see the Perspective by Waychunas). The flow of fresh water along the surfaces disrupts the equilibrium of dissolved ions, substantially changing the surface charge and the molecular orientation of the water at the interface. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1138" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1253793">1138</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1094" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1254906">1094</jats:related-article> </jats:p>

<jats:title>Invigorating convection in warm clouds</jats:title> <jats:p> Atmospheric aerosols—tiny airborne particles—affect the way clouds form and how they affect climate. Koren <jats:italic>et al.</jats:italic> investigated how the formation of warm clouds, such as those that form over the oceans, depends on pollution levels (see the Perspective by Remer). Aerosols affect cloud formation in cleaner air disproportionately more than in more polluted air. Before the widespread air pollution of the industrial era, it seems, warm convective clouds may have covered much less of the oceans than they do today. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1143" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252595">1143</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1089" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1255398">1089</jats:related-article> </jats:p>

<jats:title>An analysis of motes of the Moon maker</jats:title> <jats:p> How did the Moon form? According to the prevailing hypothesis, a Mars-sized body known as Theia smashed into Earth. Herwartz <jats:italic>et al.</jats:italic> analyzed fresh basalt samples from three Apollo landing sites and compared them with several samples of Earth's mantle. The oxygen isotope values measured in these lunar rocks differ significantly from the terrestrial material, supporting the giant-impact hypothesis. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1146" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1251117">1146</jats:related-article> </jats:p>

<jats:title>The chronology of planetary embryos</jats:title> <jats:p> Protoplanets, or early planetary embryos such as iron meteorite parent bodies, formed in the early protoplanetary disk from dust, debris, and planetesimals. Defining the precise chronology of accretion and differentiation—including core formation—of these planetary embryos will aid in a richer understanding of the chemical evolution of the solar system. Through high-precision tungsten isotope measurements, Kruijer <jats:italic>et al.</jats:italic> show that the timing of accretion and core formation for iron meteorite groups falls within 0.6 to 2 million years of the age of the solar system (see the Perspective by Elliott). Differences of timing within this group are probably a function of volatile contents of the parent bodies or spatial and chemical heterogeneity within the protoplanetary disk. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1150" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1251766">1150</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1086" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1254943">1086</jats:related-article> </jats:p>

<jats:title>Hold your breath or the catfish will find you</jats:title> <jats:p> Finding prey is hard enough in the light of day, but animals that are nocturnal or live in murky conditions face even greater challenges. Caprio <jats:italic>et al.</jats:italic> describe a sense that allows a marine catfish to detect the mere “breathing” of their prey target. External sensors on the catfish's whiskers detect pH changes generated by hidden, respiring polychaete worms. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1154" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252697">1154</jats:related-article> </jats:p>

<jats:title>Predicting stem cell renewal or differentiation</jats:title> <jats:p> Predicting complex mammalian cell behavior is extremely challenging. Dunn <jats:italic>et al.</jats:italic> developed a computational model that predicts when embryonic stem cells will self-renew or differentiate. The model revealed an essential program governing pluripotency and identifies a minimal set of components and interactions that accurately predict responses to genetic perturbation. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1156" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1248882">1156</jats:related-article> </jats:p>

<jats:title>Emerging from the shade into the light</jats:title> <jats:p> As a growing seedling emerges into the light, it needs to shift its developmental program to grow toward the light. Signaling components that flip the switch from growth in the shade to growth in the light include phytochromes, which are sensitive to red light, and transcription factors that drive the shade-adapted pattern of development. Ni <jats:italic>et al.</jats:italic> now show how phosphorylation sets these signaling partners up for destruction. The signaling established by red light invokes photomorphogenesis by promoting the destruction of the photoreceptor and its signaling partner. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6188" page="1160" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1250778">1160</jats:related-article> </jats:p>