Catálogo de publicaciones - revistas

<jats:title>Zeolites that prefer alkynes</jats:title> <jats:p> Alkenes such as ethylene and propene must be separated from alkynes before they can be converted in polymers. Drawbacks in current methods, such as hydrogenation of alkynes producing unwanted alkanes, has spurred interest in sorption separation methods. Zeolites have generally been inefficient, given the similar sizes and volatilities of the molecules. Chai <jats:italic>et al.</jats:italic> incorporated atomically dispersed divalent transition metal cations into faujasite zeolite and found that the nickel-containing analog efficiently removed alkynes from olefins through chemoselective binding at open nickel(II) sites. At ambient conditions in the presence of water and carbon dioxide, the zeolites retained separation selectivities of 100 and 92, respectively, for acetylene over ethylene and propyne over propylene for 10 adsorption-desorption cycles. </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="6494" page="1002" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aay8447">1002</jats:related-article> </jats:p>

<jats:title>Stitching alkynes into bryostatin 3</jats:title> <jats:p> The bryostatin family of marine natural products has been explored for a wide variety of pharmaceutical applications but remains challenging to source. The general structure comprises a macrocycle that contains three smaller, six-membered rings. Bryostatin 3 is distinguished by the added complexity of a fourth, fused lactone ring. Trost <jats:italic>et al.</jats:italic> report a convergent synthesis of this complex molecule, taking advantage of alkyne coupling reactions to stitch together three main fragments and asymmetric dihydroxylation and propargylation reactions to set stereochemistry. </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="6494" page="1007" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb7271">1007</jats:related-article> </jats:p>

<jats:title>Coronavirus in nonhuman primates</jats:title> <jats:p> We urgently need vaccines and drug treatments for coronavirus disease 2019 (COVID-19). Even under these extreme circumstances, we must have animal models for rigorous testing of new strategies. Rockx <jats:italic>et al.</jats:italic> have undertaken a comparative study of three human coronaviruses in cynomolgus macaques: severe acute respiratory syndrome–coronavirus (SARS-CoV) (2002), Middle East respiratory syndrome (MERS)–CoV (2012), and SARS-CoV-2 (2019), which causes COVID-19 (see the Perspective by Lakdawala and Menachery). The most recent coronavirus has a distinct tropism for the nasal mucosa but is also found in the intestinal tract. Although none of the older macaques showed the severe symptoms that humans do, the lung pathology observed was similar. Like humans, the animals shed virus for prolonged periods from their upper respiratory tracts, and like influenza but unlike the 2002 SARS-CoV, this shedding peaked early in infection. It is this cryptic virus shedding that makes case detection difficult and can jeopardize the effectiveness of isolation. </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="6494" page="1012" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb7314">1012</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6494" page="942" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abc6141">942</jats:related-article> </jats:p>

<jats:title>Alternative hosts and model animals</jats:title> <jats:p> The severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) pandemic may have originated in bats, but how it made its way into humans is unknown. Because of its zoonotic origins, SARS-CoV-2 is unlikely to exclusively infect humans, so it would be valuable to have an animal model for drug and vaccine development. Shi <jats:italic>et al.</jats:italic> tested ferrets, as well as livestock and companion animals of humans, for their susceptibility to SARS-CoV-2 (see the Perspective by Lakdawala and Menachery). The authors found that SARS-CoV-2 infects the upper respiratory tracts of ferrets but is poorly transmissible between individuals. In cats, the virus replicated in the nose and throat and caused inflammatory pathology deeper in the respiratory tract, and airborne transmission did occur between pairs of cats. Dogs appeared not to support viral replication well and had low susceptibility to the virus, and pigs, chickens, and ducks were not susceptible to SARS-CoV-2. </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="6494" page="1016" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb7015">1016</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6494" page="942" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abc6141">942</jats:related-article> </jats:p>

<jats:title>A rapid retreat</jats:title> <jats:p> Are the rates at which we observe ice shelves shrinking today representative of how fast they shrank in the past? Dowdeswell <jats:italic>et al.</jats:italic> report observations of the Antarctic seafloor that reveal the presence of submarine grounding-zone wedges on the Larsen continental shelf (see the Perspective by Jakobsson). The authors interpret these ridges as being caused by the tidal rise and fall of the ice shelf at the grounding line, which squeezes the underlying sediments when it rests on the seafloor. From this, they calculated that ice shelf retreat at this location about 14,000 years ago was at times as much as 100 times as fast as the average over the past 10,000 years. </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="6494" page="1020" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz3059">1020</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6494" page="939" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abc3583">939</jats:related-article> </jats:p>