Catálogo de publicaciones - revistas

<jats:title>Preexisting immune response to SARS-CoV-2</jats:title> <jats:p> Robust T cell responses to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus occur in most individuals with coronavirus disease 2019 (COVID-19). Several studies have reported that some people who have not been exposed to SARS-CoV-2 have preexisting reactivity to SARS-CoV-2 sequences. The immunological mechanisms underlying this preexisting reactivity are not clear, but previous exposure to widely circulating common cold coronaviruses might be involved. Mateus <jats:italic>et al.</jats:italic> found that the preexisting reactivity against SARS-CoV-2 comes from memory T cells and that cross-reactive T cells can specifically recognize a SARS-CoV-2 epitope as well as the homologous epitope from a common cold coronavirus. These findings underline the importance of determining the impacts of preexisting immune memory in COVID-19 disease severity. </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="6512" page="89" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd3871">89</jats:related-article> </jats:p>

<jats:title>Pathways for ductility</jats:title> <jats:p> Alloys containing multiple elements can be very strong but often suffer from poor ductility. F. Wang <jats:italic>et al.</jats:italic> found that different mechanisms accommodated plasticity in a molybdenum-niobium-titanium multiprincipal element alloy (see the Perspective by Cairney). Instead of so-called “screw” dislocations, deformation is accommodated by multiple pathways that include “edge” dislocations and activation of crystallographic slip planes. These results offer a design paradigm for developing new high-strength alloys. </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="6512" page="95" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aba3722">95</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6512" page="37" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd6587">37</jats:related-article> </jats:p>

<jats:title>Paper in, product out</jats:title> <jats:p> A typical chemist running a known reaction will start by finding the method described in a published paper. Mehr <jats:italic>et al.</jats:italic> report a software platform that uses natural language processing to translate the organic chemistry literature directly into editable code, which in turn can be compiled to drive automated synthesis of the compound in the laboratory. The synthesis procedure is intended to be universally applicable to robotic systems operating in a batch reaction architecture. The full process is demonstrated for synthesis of an analgesic as well as common oxidizing and fluorinating agents. </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="6512" page="101" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abc2986">101</jats:related-article> </jats:p>

<jats:title>Relieving unwanted strain</jats:title> <jats:p> Although the α-phase of formamidinium lead iodide (FAPbI <jats:sub>3</jats:sub> ) has a suitable bandgap for use in solar cells, it must be stabilized with additional cations. These compositions can adversely affect the bandgap and produce lattice strain that creates trap sites for charge carriers. Kim <jats:italic>et al.</jats:italic> found that substituting small, equimolar amounts of cesium and methylenediammonium cations for formamidinium reduced the lattice strain and trap densities. The enhancement in open-circuit voltage led to a certified power conversion efficiency of 24.4%, and encapsulated devices retained 90% of their initial efficiency after 400 hours of maximal power point operating conditions. </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="6512" page="108" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abc4417">108</jats:related-article> </jats:p>

<jats:title>Convergence of paradigms yields patterns</jats:title> <jats:p> In embryo development, spatial patterns of distinct cell types arise reproducibly. In the zebrafish spinal cord, neural progenitors form stereotypic stripe patterns despite the noisy instructive signals and large-scale cellular rearrangement required during morphogenesis. Tsai <jats:italic>et al.</jats:italic> show that a cell type–specific adhesion code, regulated by a Shh morphogen gradient composed of three adhesion molecules, provides adhesion specificity for three neural progenitor types and mediates patterning robustness in the zebrafish spinal cord. Although insufficient on their own, the integration of the morphogen gradient and differential adhesion mechanisms enables robust pattern formation during tissue morphogenesis. </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="6512" page="113" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aba6637">113</jats:related-article> </jats:p>

<jats:title>Consider both water and land</jats:title> <jats:p> When designing terrestrial reserves, it is common to consider the needs of species and systems from a terrestrial perspective, with an assumption that any freshwater systems will benefit as well. Leal <jats:italic>et al.</jats:italic> tested this assumption by analyzing data from two locations in the Brazilian Amazon and found that it is far from accurate: Terrestrial systems confer little benefit to freshwater systems (see the Perspective by Abell and Harrison). However, the authors also found that integrating the needs of freshwater species into overall reserve planning increased freshwater benefits by 600% while only decreasing terrestrial outcomes by 1%. They argue that reserve planning must take freshwater systems into account if they are to protect across both realms. </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="6512" page="117" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aba7580">117</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6512" page="38" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abe3887">38</jats:related-article> </jats:p>

<jats:title>Two rather than one</jats:title> <jats:p> For several decades, it has been believed that the mammalian sex-determining gene <jats:italic>Sry</jats:italic> contains a single exon. Miyawaki <jats:italic>et al.</jats:italic> have now identified a cryptic second exon of mouse <jats:italic>Sry</jats:italic> . Loss- and gain-of-function analyses revealed that the two-exon SRY (SRY-T), not the canonical single exon–encoded SRY (SRY-S), is the bona fide testis-determining factor. <jats:italic>Sry</jats:italic> exon2 is composed of retrotransposon-derived sequences. The SRY-S carboxyl terminus contains a degradation sequence (degron), whereas the SRY-T carboxyl terminus encoded in the <jats:italic>Sry</jats:italic> exon2 is degron free, thereby conferring protein stability on SRY-T. </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="6512" page="121" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abb6430">121</jats:related-article> </jats:p>

<jats:title>Competitive cooling with capacitors</jats:title> <jats:p> Current large-scale cooling devices use vapor compression refrigeration. The efficiency of air conditioners has been optimized, but they can be noisy and rely on problematic greenhouse gases. Two groups now present designs for electrocaloric cooling using lead scandium tantalate capacitors that change temperature under an electric field. Y. Wang <jats:italic>et al.</jats:italic> obtained a very large heat flux using only solid materials and a cooling fan to remove heat from their device. Torello <jats:italic>et al.</jats:italic> used fluids for heat transfer, leading to a very large temperature difference between the hot side and the cold side. The new designs demonstrate the potential for devices that might be competitive with vapor compression–based appliances with further optimization. </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="6512" page="129" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aba2648">129</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6512" page="125" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abb8045">125</jats:related-article> </jats:p>

<jats:title>Competitive cooling with capacitors</jats:title> <jats:p> Current large-scale cooling devices use vapor compression refrigeration. The efficiency of air conditioners has been optimized, but they can be noisy and rely on problematic greenhouse gases. Two groups now present designs for electrocaloric cooling using lead scandium tantalate capacitors that change temperature under an electric field. Y. Wang <jats:italic>et al.</jats:italic> obtained a very large heat flux using only solid materials and a cooling fan to remove heat from their device. Torello <jats:italic>et al.</jats:italic> used fluids for heat transfer, leading to a very large temperature difference between the hot side and the cold side. The new designs demonstrate the potential for devices that might be competitive with vapor compression–based appliances with further optimization. </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="6512" page="129" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aba2648">129</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6512" page="125" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abb8045">125</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>