Catálogo de publicaciones - revistas

<jats:title>Stellar oscillations show differential rotation</jats:title> <jats:p> The Sun rotates faster at its equator than at its poles. This process is known as differential rotation and is seen in the motion of sunspots. Helioseismology has shown that the effect extends into the Sun's interior. It has not been possible to measure whether other stars also experience equivalent differential rotation. Benomar <jats:italic>et al.</jats:italic> used the Kepler spacecraft to monitor stellar oscillations of a group of Sun-like stars. By decomposing the oscillations into separate frequencies, they searched for signs of differential rotation. Several stars do indeed seem to have equators that spin faster than their poles, and none indicated the opposite pattern. </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="6408" page="1231" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aao6571">1231</jats:related-article> </jats:p>

<jats:title>A swift citrusy path to chiral phosphorus</jats:title> <jats:p> The phosphates in the backbones of DNA and RNA are often drawn like crosses but are in fact tetrahedral. Sulfur is sometimes substituted for one of the phosphate oxygens during development of nucleotide-based drugs. Because of the geometry, this swap can lead to two different isomers. Knouse <jats:italic>et al.</jats:italic> report a pair of phosphorus reagents that conveniently produce either isomer selectively. This ability depended on the configuration of appended limonene substituents that are subsequently jettisoned. In addition to simplifying the route to sulfur-substituted oligonucleotides, these reagents will enable more precise studies of each isomer's distinct bioactivity. </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="6408" page="1234" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aau3369">1234</jats:related-article> </jats:p>

<jats:title>Counting the state of a qubit</jats:title> <jats:p> Operation of a quantum computer will be reliant on the ability to correct errors. This will typically require the fast, high-fidelity quantum nondemolition measurement of a large number of qubits. Opremcak <jats:italic>et al.</jats:italic> describe a method that uses a photon counter to determine the state of a superconducting qubit. Being able to simply read out the qubit state as a photon number removes the need for bulky components and large experimental overhead that characterizes present approaches. </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="6408" page="1239" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aat4625">1239</jats:related-article> </jats:p>

<jats:title>Robust assembly of aromatic molecules</jats:title> <jats:p> Organic materials can exhibit high porosity, but the structures often collapse or decompose at high temperatures. Yamagishi <jats:italic>et al.</jats:italic> synthesized an aromatic molecule that bears a symmetrical outer shell of three dipyridylphenyl wedges and crystallized it from highly dielectric solvents. Porous crystals formed with complex pore-wall structures that resulted from labile C–H⋯N bonds and van der Waals forces. Despite the weakness of these interactions, the porous structure was stable up to 202°C and could be recovered after collapse by exposure to solvent vapor. </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="6408" page="1242" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aat6394">1242</jats:related-article> </jats:p>

<jats:title>Confirming the identity of early animals</jats:title> <jats:p> The first complex organisms emerged during the Ediacaran period, around 600 million years ago. The taxonomic affiliation of many of these organisms has been difficult to discern. Fossils of <jats:italic>Dickinsonia</jats:italic> , bilaterally symmetrical oval organisms, have been particularly difficult to classify. Bobrovskiy <jats:italic>et al.</jats:italic> conducted an analysis using lipid biomarkers obtained from <jats:italic>Dickinsonia</jats:italic> fossils and found that the fossils contained almost exclusively cholesteroids, a marker found only in animals (see the Perspective by Summons and Erwin). Thus, <jats:italic>Dickinsonia</jats:italic> were basal animals. This supports the idea that the Ediacaran biota may have been a precursor to the explosion of animal forms later observed in the Cambrian, about 500 million years ago. </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="6408" page="1246" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aat7228">1246</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6408" page="1198" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aau9710">1198</jats:related-article> </jats:p>

<jats:title>Early shifts lead to big changes</jats:title> <jats:p> Mammals represent one of the most morphologically diverse taxonomic groups. One of the unique features underlying this diversity is variability of the spine, which facilitates everything from flexibility for speedy running and support for upright walking. Jones <jats:italic>et al.</jats:italic> studied a group ancestral to modern mammals—nonmammalian synapsids, or mammal-like reptiles. As forelimb function diversified, the spine developed distinct regions. These regions then differentiated further, leading to the highly varied mammalian forms we see 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="6408" page="1249" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aar3126">1249</jats:related-article> </jats:p>

<jats:title>Building smarter synthetic biological circuits</jats:title> <jats:p> Synthetic genetic and biological regulatory circuits can enable logic functions to form the basis of biological computing; synthetic biology can also be used to control cell behaviors (see the Perspective by Glass and Alon). Andrews <jats:italic>et al.</jats:italic> used mathematical models and computer algorithms to combine standardized components and build programmable genetic sequential logic circuits. Such circuits can perform regulatory functions much like the biological checkpoint circuits of living cells. Circuits composed of interacting proteins could be used to bypass gene regulation, interfacing directly with cellular pathways without genome modification. Gao <jats:italic>et al.</jats:italic> engineered proteases that regulate one another, respond to diverse inputs that include oncogene activation, process signals, and conditionally activate responses such as those leading to cell death. This platform should facilitate development of “smart” therapeutic circuits for future biomedical applications. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.aap8987">eaap8987</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6408" page="1252" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aat5062">1252</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6408" page="1199" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aav2497">1199</jats:related-article> </jats:p>

<jats:title>Expanding the targeting space of Cas9</jats:title> <jats:p> CRISPR-Cas9 associates with a guide RNA to target and cleave a specific DNA site next to a protospacer adjacent motif (PAM). <jats:italic>Streptococcus pyogenes</jats:italic> Cas9 (SpCas9), the one most often used for genome editing, only recognizes the NGG sequence (where N is any nucleobase) as the PAM, which restricts regions in the genome that can be targeted. To address this limitation, Nishimasu <jats:italic>et al.</jats:italic> created a SpCas9 variant that recognizes NG rather than NGG. The SpCas9-NG variant increased the targeting range, had a specificity similar to that of the wild-type enzyme, and could be used with a base editor. Thus, SpCas9-NG is a powerful addition to the CRISPR-Cas9 genome engineering toolbox and will be useful in a broad range of applications, from basic research to clinical therapeutics. </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="6408" page="1259" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aas9129">1259</jats:related-article> </jats:p>

<jats:p> The 2019 Gordon Research Conference schedule was published on pages 1264 to 1273 of this issue of the print version of <jats:italic>Science</jats:italic> . The current schedule can also be found online at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.grc.org/">www.grc.org/</jats:ext-link> . </jats:p>

<jats:p>A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.</jats:p>