Catálogo de publicaciones - revistas

<jats:title>Wrap-around invisibility cloak</jats:title> <jats:p> An invisibility cloak can be used to conceal an object from view by guiding light around it. Most cloaks developed so far have bulky structures that are difficult to scale up for hiding large objects. To design a thin invisibility cloak that can be wrapped around an object such as a sheet or skin, Ni <jats:italic>et al.</jats:italic> designed a two-dimensional metamaterial surface. Such flexible, highly reflective materials could be manufactured at large scale to hide large objects. </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="6254" page="1310" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac9411">1310</jats:related-article> </jats:p>

<jats:title>Thinning films induces ferroelectricity</jats:title> <jats:p> Thin ferroelectric films are needed in computers and medical devices. However, traditional ferroelectric films typically become less and less polarized the thinner the films become. Instead of using a good ferroelectric and making it thinner, Lee <jats:italic>et al.</jats:italic> started with SrTiO <jats:sup>3</jats:sup> , which in its bulk form is not ferroelectric. This material does have naturally occurring nanosized polarized regions. and when the thickness of the SrTiO <jats:sub>3</jats:sub> films reaches the typical size of these regions, the whole film aligns and becomes ferroelectric. </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="6254" page="1314" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa6442">1314</jats:related-article> </jats:p>

<jats:title>Entangling atoms by persistent poking</jats:title> <jats:p> In quantum mechanics, repeated measurements targeting a particular unoccupied state of the system can keep that state from being occupied. Barontini <jats:italic>et al.</jats:italic> used this so-called quantum Zeno effect to restrict the dynamics of an ensemble of 36 <jats:sup>87</jats:sup> Rb atoms acting as qubits and residing in an optical cavity. The measurement of the cavity transmission blocked off the collective state in which all qubits were in their ground state. The ensuing dynamics resulted in the entanglement of the atoms, creating a potential resource for quantum information processing. </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="6254" page="1317" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa0754">1317</jats:related-article> </jats:p>

<jats:title>Cooler ceramic fuel cells</jats:title> <jats:p> Ceramic ion conductors can be used as electrolytes in fuel cells using natural gas. One drawback of such solid-oxide fuel cells that conduct oxygen ions is their high operating temperatures (at least 600°C). Duan <jats:italic>et al.</jats:italic> have made a proton-conducting ceramic fuel cell with a modified cathode material that exhibits high performance on methane fuel at 500°C (see the Perspective by Gorte). </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="6254" page="1321" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab3987">1321</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6254" page="1290" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aad0432">1290</jats:related-article> </jats:p>

<jats:title>Lighting the way to aryl C-N bonding</jats:title> <jats:p> Medicinal chemists like to add N bonds to the C atoms of aromatic rings to make bioactive compounds. By harnessing the energy in visible light, Romero <jats:italic>et al.</jats:italic> made these links and transformed C-H into C-N bonds. They used a blue-absorbing acridinium ion to activate a ring C for an incoming N partner. A nitroxyl radical co-catalyst (TEMPO) then choreographed the transfer of the H atom to O. The reaction worked for a broad range of substrates, including ammonium as a N source. </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="6254" page="1326" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac9895">1326</jats:related-article> </jats:p>

<jats:title>Driving dissolution with x-rays</jats:title> <jats:p> Carbonate minerals are important for Earth's carbon cycle. They precipitate directly from solution into diverse materials, depending on their physical or biological source. Whether carbonate minerals grow or dissolve is controlled by the thermodynamic drivers of the mineral/water interface. To control and observe the reactions, Lanaait <jats:italic>et al.</jats:italic> developed a synchrotron x-ray technique that images calcium carbonate surfaces in water and selectively tunes the solution saturation state (see the Perspective by Wolthers). The x-ray beam drives fast-moving reaction fronts far from equilibrium that are more limited by solution-ion transport than by surface processes. </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="6254" page="1330" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab3272">1330</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6254" page="1288" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aad0852">1288</jats:related-article> </jats:p>

<jats:title>Youthful damage limitation in stem cells</jats:title> <jats:p> Every day brings more risk of damage to stem cells, which could have consequences for the whole organism. Moore <jats:italic>et al.</jats:italic> observed that dividing neural stem cells in rodents establish a diffusion barrier that restricts damaged proteins to one daughter cell, leaving the other with intact molecules. But with age this diffusion barrier weakens, so that replicating stem cells of older animals are less able to exclude damaged proteins than are the stem cells of younger rodents. </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="6254" page="1334" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac9868">1334</jats:related-article> </jats:p>

<jats:title>The devil in the dengue details</jats:title> <jats:p> Along with their mosquito vectors, dengue viruses are spreading worldwide to infect millions of people. For a few, subsequent infection results in lethal hemorrhagic disease. Katzelnick <jats:italic>et al.</jats:italic> used antibody-binding data to map structural divergence and antigenic variation among dengue viruses. Comparing results in monkeys and humans, the viruses approximately clustered into the four known groups. However, the four virus groups showed as much antigenic distance within a group as between groups. This finding helps explain why immune responses to dengue are highly variable, and it has complex implications for epidemiology, disease, and vaccine deployment. </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="6254" page="1338" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac5017">1338</jats:related-article> </jats:p>

<jats:title>Greenlanders' genomes signal a fatty diet</jats:title> <jats:p> The evolutionary consequences of inhabiting a challenging environment can be seen within the genomes of Greenland Inuit. Fumagalli <jats:italic>et al.</jats:italic> have found signs of selection for genetic variants in fat metabolism, not just for promoting heat-producing brown fat cells but also for coping with the large amounts of polyunsaturated fatty acids found in their seafood diet (see the Perspective by Tishkoff). Genes under selection in these populations have a strong effect on height and weight of up to 2 cm and 4 kg, respectively, as well as a protective effect on cholesterol and triglyceride levels. </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="6254" page="1343" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab2319">1343</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6254" page="1282" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aad0584">1282</jats:related-article> </jats:p>

<jats:title>Caught in the act of copying</jats:title> <jats:p>The genomes of double-stranded RNA (dsRNA) viruses consist of about a dozen dsRNA segments enclosed by a protein coat. Inside the host cell, the coat remains intact, and the dsRNAs have to replicate within the coat. Liu and Cheng used cryo–electron microscopy of cypovirus particles to catch the dsRNAs in the act of being copied. The structures revealed that the RNA formed a liquid-crystalline array on which viral enzymes carry out multiple rounds of transcription to replicate the viral genome.</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="6254" page="1347" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa4938">1347</jats:related-article> </jats:p>