Catálogo de publicaciones - revistas

<jats:title>A logarithmic signature</jats:title> <jats:p> Some one-dimensional disordered interacting quantum systems have been theoretically predicted to display a property termed many-body localization (MBL), where the system retains the memory of its initial state and fails to thermalize. However, proving experimentally that something does not occur is tricky. Instead, physicists have proposed monitoring the entanglement entropy of the system, which should grow logarithmically with evolution time in an MBL system. Lukin <jats:italic>et al.</jats:italic> observed this characteristic logarithmic trend in a disordered chain of interacting atoms of rubidium-87. This method should be generalizable to other experimental platforms and higher dimensions. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://www.sciencemag.org/content/354/6300/256.full">256</jats:ext-link> </jats:p>

<jats:title>An entropic look into entanglement</jats:title> <jats:p> Quantum systems are predicted to be better at information processing than their classical counterparts, and quantum entanglement is key to this superior performance. But how does one gauge the degree of entanglement in a system? Brydges <jats:italic>et al.</jats:italic> monitored the build-up of the so-called Rényi entropy in a chain of up to 10 trapped calcium ions, each of which encoded a qubit. As the system evolved, interactions caused entanglement between the chain and the rest of the system to grow, which was reflected in the growth of the Rényi entropy. </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="6437" page="260" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aau4963">260</jats:related-article> </jats:p>

<jats:title>Samarium supersensors</jats:title> <jats:p> Piezoelectric materials produce electric charge in response to changes in stress and are thus good sensor materials. One challenge has been growing single-crystal piezoelectrics with uniform properties. As of now, much of the crystal is discarded because of compositional variations. Li <jats:italic>et al.</jats:italic> synthesized single crystals of samarium-doped Pb(Mg <jats:sub>1/3</jats:sub> Nb <jats:sub>2/3</jats:sub> )O <jats:sub>3</jats:sub> -PbTiO <jats:sub>3</jats:sub> that have uniform and extremely high piezoelectric properties (see the Perspective by Hlinka). These crystals are ideal for a variety of sensing applications and could reduce cost by eliminating waste. </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="6437" page="264" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw2781">264</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="228" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax0693">228</jats:related-article> </jats:p>

<jats:title>Hayabusa2 at the asteroid Ryugu</jats:title> <jats:p> Asteroids fall to Earth in the form of meteorites, but these provide little information about their origins. The Japanese mission Hayabusa2 is designed to collect samples directly from the surface of an asteroid and return them to Earth for laboratory analysis. Three papers in this issue describe the Hayabusa2 team's study of the near-Earth carbonaceous asteroid 162173 Ryugu, at which the spacecraft arrived in June 2018 (see the Perspective by Wurm). Watanabe <jats:italic>et al.</jats:italic> measured the asteroid's mass, shape, and density, showing that it is a “rubble pile” of loose rocks, formed into a spinning-top shape during a prior period of rapid spin. They also identified suitable landing sites for sample collection. Kitazato <jats:italic>et al.</jats:italic> used near-infrared spectroscopy to find ubiquitous hydrated minerals on the surface and compared Ryugu with known types of carbonaceous meteorite. Sugita <jats:italic>et al.</jats:italic> describe Ryugu's geological features and surface colors and combined results from all three papers to constrain the asteroid's formation process. Ryugu probably formed by reaccumulation of rubble ejected by impact from a larger asteroid. These results provide necessary context to understand the samples collected by Hayabusa2, which are expected to arrive on Earth in December 2020. </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="6437" page="268" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav8032">268</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="272" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav7432">272</jats:related-article> , p. <jats:related-article issue="6437" page="252" related-article-type="in-this-issue" vol="364">252</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="230" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax3089">230</jats:related-article> </jats:p>

<jats:title>Hayabusa2 at the asteroid Ryugu</jats:title> <jats:p> Asteroids fall to Earth in the form of meteorites, but these provide little information about their origins. The Japanese mission Hayabusa2 is designed to collect samples directly from the surface of an asteroid and return them to Earth for laboratory analysis. Three papers in this issue describe the Hayabusa2 team's study of the near-Earth carbonaceous asteroid 162173 Ryugu, at which the spacecraft arrived in June 2018 (see the Perspective by Wurm). Watanabe <jats:italic>et al.</jats:italic> measured the asteroid's mass, shape, and density, showing that it is a “rubble pile” of loose rocks, formed into a spinning-top shape during a prior period of rapid spin. They also identified suitable landing sites for sample collection. Kitazato <jats:italic>et al.</jats:italic> used near-infrared spectroscopy to find ubiquitous hydrated minerals on the surface and compared Ryugu with known types of carbonaceous meteorite. Sugita <jats:italic>et al.</jats:italic> describe Ryugu's geological features and surface colors and combined results from all three papers to constrain the asteroid's formation process. Ryugu probably formed by reaccumulation of rubble ejected by impact from a larger asteroid. These results provide necessary context to understand the samples collected by Hayabusa2, which are expected to arrive on Earth in December 2020. </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="6437" page="268" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav8032">268</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="272" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav7432">272</jats:related-article> , p. <jats:related-article issue="6437" page="252" related-article-type="in-this-issue" vol="364">252</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="230" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax3089">230</jats:related-article> </jats:p>

<jats:title>Wet surface sightings in clusters</jats:title> <jats:p> In principle, the surface structure of water (H <jats:sub>2</jats:sub> O) should be discernable from the O–H vibrations. In practice, however, so many configurations rapidly interconvert that the bands are bewilderingly broad. Yang <jats:italic>et al.</jats:italic> studied a cluster of 20 H <jats:sub>2</jats:sub> O surrounding a cesium ion, using isotopomers that vary in the position of one H <jats:sub>2</jats:sub> O amid 19 heavy water (D <jats:sub>2</jats:sub> O) molecules. Precisely assigned spectral features from contributing configurations mapped well onto a bulk surface spectrum. </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="6437" page="275" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw4086">275</jats:related-article> </jats:p>

<jats:title>Atomic packing controls exciton lifetime</jats:title> <jats:p> Like semiconductors, small metallic clusters can absorb light and create excitons (electron-hole pairs). In ligand-capped gold clusters of 30 to 40 atoms (Au <jats:sub>30</jats:sub> to Au <jats:sub>40</jats:sub> ) that adopt the usual face-centered cubic packing, the lifetime of these excitons is ∼100 nanoseconds. Zhou <jats:italic>et al.</jats:italic> found that atomic packing and molecular orbital overlap can greatly affect carrier lifetimes. Despite having similar bandgaps to those of face-centered cubic clusters, a hexagonal close-packed Au <jats:sub>30</jats:sub> cluster had a much shorter lifetime (∼1 nanosecond), and a body-centered cubic Au <jats:sub>38</jats:sub> cluster had a lifetime of ∼5 microseconds, which is comparable to bulk silicon. </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="6437" page="279" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw8007">279</jats:related-article> </jats:p>

<jats:title>Tissue specificity of tumor suppression</jats:title> <jats:p> It is well known that the loss of tumor suppressor genes leads to a limited subset of cancers in specific tissues. But why just those tissues? He <jats:italic>et al.</jats:italic> found a relatively simple explanation for how this tissue selectivity works for the tumor suppressor BAP1 using a mouse model of BAP1-induced cancer. In most cells, loss of BAP1 caused cell death or apoptosis. But in the tissues that formed tumors, differences in the regulation of genes with antiapoptotic effects allowed the cells to survive, even though BAP1 was lost. At least for this one tumor suppressor, its inactivation would normally cause a cell to die; however, this mechanism is absent in a subset of tissues, allowing the cells to proliferate and cause a tumor. </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="6437" page="283" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav4902">283</jats:related-article> </jats:p>

<jats:title>Spotting off-targets from gene editing</jats:title> <jats:p> Unintended genomic modifications limit the potential therapeutic use of gene-editing tools. Available methods to find off-targets generally do not work in vivo or detect single-nucleotide changes. Three papers in this issue report new methods for monitoring gene-editing tools in vivo (see the Perspective by Kempton and Qi). Wienert <jats:italic>et al.</jats:italic> followed the recruitment of a DNA repair protein to DNA breaks induced by CRISPR-Cas9, enabling unbiased detection of off-target editing in cellular and animal models. Zuo <jats:italic>et al.</jats:italic> identified off-targets without the interference of natural genetic heterogeneity by injecting base editors into one blastomere of a two-cell mouse embryo and leaving the other genetically identical blastomere unedited. Jin <jats:italic>et al.</jats:italic> performed whole-genome sequencing on individual, genome-edited rice plants to identify unintended mutations. Cytosine, but not adenine, base editors induced numerous single-nucleotide variants in both mouse and rice. </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="6437" page="286" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav9023">286</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="289" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav9973">289</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="292" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw7166">292</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="234" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax1827">234</jats:related-article> </jats:p>

<jats:title>Spotting off-targets from gene editing</jats:title> <jats:p> Unintended genomic modifications limit the potential therapeutic use of gene-editing tools. Available methods to find off-targets generally do not work in vivo or detect single-nucleotide changes. Three papers in this issue report new methods for monitoring gene-editing tools in vivo (see the Perspective by Kempton and Qi). Wienert <jats:italic>et al.</jats:italic> followed the recruitment of a DNA repair protein to DNA breaks induced by CRISPR-Cas9, enabling unbiased detection of off-target editing in cellular and animal models. Zuo <jats:italic>et al.</jats:italic> identified off-targets without the interference of natural genetic heterogeneity by injecting base editors into one blastomere of a two-cell mouse embryo and leaving the other genetically identical blastomere unedited. Jin <jats:italic>et al.</jats:italic> performed whole-genome sequencing on individual, genome-edited rice plants to identify unintended mutations. Cytosine, but not adenine, base editors induced numerous single-nucleotide variants in both mouse and rice. </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="6437" page="286" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav9023">286</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="289" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav9973">289</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="292" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw7166">292</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6437" page="234" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax1827">234</jats:related-article> </jats:p>