Catálogo de publicaciones - revistas

<jats:title>A direct route to pure peroxide</jats:title> <jats:p> Despite the widespread use of hydrogen peroxide as an oxidant and disinfectant, its commercial synthesis still requires inefficient concentration and purification steps. Xia <jats:italic>et al.</jats:italic> now report an electrochemical approach to synthesizing pure peroxide solutions straight from hydrogen and oxygen. Using a solid-state electrolyte, they avoid contamination of the product solution by extraneous ions. Varying the flow rate of water through the electrochemical cell tunes the final concentration over a range from 0.3% to 20% by weight. </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="6462" page="226" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aay1844">226</jats:related-article> </jats:p>

<jats:title>Probing a galaxy halo with a radio burst</jats:title> <jats:p> Fast radio bursts (FRBs) are millisecond flashes of radio emission from distant galaxies. It has only recently become possible to locate single bursts precisely enough to determine the host galaxy. Prochaska <jats:italic>et al.</jats:italic> have observed and localized a FRB using a radio interferometer. The line of sight to the host galaxy coincidentally passes through the outskirts of a closer foreground galaxy. By analyzing the propagation of the FRB, the authors put constraints on the density and magnetization of gas in the outskirts of the foreground galaxy. The technique provides complementary information to existing methods using background quasars. </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="6462" page="231" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aay0073">231</jats:related-article> </jats:p>

<jats:title>Imaging a chemisorption process</jats:title> <jats:p> At low temperatures, a molecule may adsorb to a surface only through weak forces (physisorption), and only upon heating and overcoming an energetic barrier does it form a strong covalent bond (chemisorption). Huber <jats:italic>et al.</jats:italic> imaged this transition for an atomic force microscopy tip terminating in a carbon monoxide molecule. Although the oxygen atom of the tip is normally considered to act like a rare gas atom, interacting only through van der Waals interactions, at short distances directly above a transition metal atom, it transitions to a strongly interacting chemisorption state. </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="6462" page="235" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aay3444">235</jats:related-article> </jats:p>

<jats:title>Unconventional oscillations</jats:title> <jats:p> At sufficiently low temperatures, superconductors expel an applied magnetic field. However, if the topology of the superconductor is nontrivial—for example, if there is a hole in the sample—there can be a nonzero magnetic flux inside the hole. This flux can only take certain discrete values, and the superconducting critical temperature has maxima at the corresponding values of the magnetic field. Li <jats:italic>et al.</jats:italic> studied these so-called Little-Parks oscillations in superconducting rings made out of polycrystalline thin films of β-Bi <jats:sub>2</jats:sub> Pd. They found that the phase of the oscillations was shifted by π compared with oscillations observed in most superconductors, as predicted for certain unconventional pairing symmetries. </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="6462" page="238" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aau6539">238</jats:related-article> </jats:p>

<jats:title>Selecting for ethylene</jats:title> <jats:p> Purification of ethylene from other gases produced during its synthesis, such as acetylene, ethane, and carbon dioxide, is an energy-intensive process. Chen <jats:italic>et al.</jats:italic> use a mixture of microporous metal-organic framework physisorbents that are selective for one of these four gases. A series of sorbents in a packed-bed geometry produced ethylene pure enough for making polymers. </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="6462" page="241" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax8666">241</jats:related-article> </jats:p>

<jats:title> Fine control of brain GABA <jats:sub>A</jats:sub> receptors </jats:title> <jats:p> GABA <jats:sub>A</jats:sub> (γ-aminobutyric acid type A) receptors are ligand-gated anion channels that mediate fast inhibitory transmission in the mammalian brain. Han <jats:italic>et al.</jats:italic> investigated if a protein called SHISA7 was involved in regulating GABA <jats:sub>A</jats:sub> receptor expression and function (see the Perspective by Rudolph and Moss). SHISA7 was found at GABA-releasing synapses, where it interacted with GABA <jats:sub>A</jats:sub> receptors, controlled receptor concentration at the synapse, sped up receptor deactivation kinetics, and modulated some behavioral properties of benzodiazepines. SHISA7 thus affects surface expression, gating kinetics, and pharmacology of GABA <jats:sub>A</jats:sub> receptors in the brain. </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="6462" page="246" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax5719">246</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6462" page="185" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaz3176">185</jats:related-article> </jats:p>

<jats:title>An inhibitor causes neuronal excitation</jats:title> <jats:p> Glycine is thought to be primarily an inhibitory neurotransmitter. However, it also acts as a coagonist on excitatory <jats:italic>N</jats:italic> -methyl-D-aspartate (NMDA) receptors. Otsu <jats:italic>et al.</jats:italic> examined the function of the NMDA receptor subunit combination GluN1/GluN3A in the medial habenula (MHb) of adult mice. This NMDA receptor subunit combination in MHb neurons is activated by glycine released from astrocytes. Activation of GluN1/GluN3A NMDA receptors causes depolarization and increased spiking of MHb neurons. Reducing GluN3A receptor subunit levels in the MHb blocks conditioned place aversion. </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="6462" page="250" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax1522">250</jats:related-article> </jats:p>

<jats:title>The future of nature's contributions</jats:title> <jats:p> A recent Global Assessment by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services has emphasized the urgent need to determine where and how nature's contribution matters most to people. Chaplin-Kramer <jats:italic>et al.</jats:italic> have developed a globalscale modeling of ecosystem services, focusing on water quality regulation, coastal protection, and crop pollination (see the Perspective by Balvanera). By 2050, up to 5 billion people may be at risk from diminishing ecosystem services, particularly in Africa and South Asia. </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="6462" page="255" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaw3372">255</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6462" page="184" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaz1433">184</jats:related-article> </jats:p>

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