Catálogo de publicaciones - revistas

<jats:title>Tougher when stressed</jats:title> <jats:p> Hydrogels are typically weak materials because they contain only a small fraction of polymeric material highly swollen with water. Strength can be increased by adding extra cross-linking or interpenetrating networks with some sacrificial bonds to enhance toughness; however, these properties deteriorate upon stretching and may be slow to recover after relaxation. Liu <jats:italic>et al.</jats:italic> developed polyethylene glycol hydrogels cross-linked with moderate fractions of polymers that form sliding rings. These allow the chain to orient in parallel when stretched, leading to rapid and reversible strain-induced crystallization and thus much tougher hydrogels. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , aaz6694, this issue p. <jats:related-article issue="6546" page="1078" related-article-type="in-this-issue" vol="372">1078</jats:related-article> </jats:p>

<jats:title>An intrinsic gamma-ray burst afterglow</jats:title> <jats:p>Long gamma-ray bursts (GRBs) are emitted by relativistic jets generated during the collapse of a massive star in a distant galaxy. The GRB itself lasts only a few seconds but is followed by an afterglow that can persist for hours or days. The H.E.S.S. Collaboration observed the afterglow of GRB 190829A, a nearby long GRB. The proximity of this burst allowed it to be detected at tera–electron volt energies that would otherwise be absorbed in the intergalactic medium. By analyzing the spectrum and light curve at x-ray and gamma-ray wavelengths, the authors show that the afterglow cannot be explained by standard models.</jats:p> <jats:p> <jats:italic>Science</jats:italic> , abe8560, this issue p. <jats:related-article issue="6546" page="1081" related-article-type="in-this-issue" vol="372">1081</jats:related-article> </jats:p>

<jats:title>Obesity genes working together</jats:title> <jats:p> The biological causes of obesity are not well understood. Sobreira <jats:italic>et al.</jats:italic> examined the chromatin interactions between key genes in a locus known for its associations with obesity in human patients. In addition to directly interrogating the connections between these genes and examining the mechanisms that regulate their activity, the authors used mouse models to study the target genes' effects on both adipose tissue and brain cells that play a role in regulating dietary preferences. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abf1008, this issue p. <jats:related-article issue="6546" page="1085" related-article-type="in-this-issue" vol="372">1085</jats:related-article> </jats:p>

<jats:title>Back to school—safely</jats:title> <jats:p> Severe COVID-19 in children is rare, but many schools remain closed because the transmission risk that school contact poses to adults and the wider community is unknown. Observing the heterogeneity of approaches taken among U.S. school districts, Lessler <jats:italic>et al.</jats:italic> investigated how different strategies influence COVID-19 transmission rates in the wider community using COVID-19 Symptom Survey data from Carnegie Mellon and Facebook. The authors found that when mitigation measures are in place, transmission within schools is limited and infection rates mirror that of the surrounding community. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abh2939, this issue p. <jats:related-article issue="6546" page="1092" related-article-type="in-this-issue" vol="372">1092</jats:related-article> </jats:p>

<jats:title>Antarctic paleotemperatures</jats:title> <jats:p> It has been widely thought that East Antarctica was ∼9°C cooler during the Last Glacial Maximum, close to the ∼10°C difference between then and now determined independently for West Antarctica. Buizert <jats:italic>et al.</jats:italic> used borehole thermometry, firn density reconstructions, and climate modeling to show that the temperature in East Antarctica was actually only ∼4° to 7°C cooler during the Last Glacial Maximum. This result has important consequences for our understanding of Antarctic climate, polar amplification, and global climate change. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abd2897, this issue p. <jats:related-article issue="6546" page="1097" related-article-type="in-this-issue" vol="372">1097</jats:related-article> </jats:p>

<jats:title>IgG fucosylation predicts dengue severity</jats:title> <jats:p> Secondary infections with dengue virus (DENV) can produce life-threatening symptoms, including thrombocytopenia and hemorrhagic disease, when preexisting DENV-reactive immunoglobulin G1 (IgG1) antibodies promote the infection of immune cells. Although severe dengue symptoms are associated with increased levels of afucosylated IgG1 glycoforms, it is unclear whether this is simply a result of the infection or if it is a preexisting phenomenon that can dictate susceptibility to this disease. Bournazos <jats:italic>et al.</jats:italic> studied the Fab and Fc structures of anti-DENV antibodies from patients before and after infection and with variable disease outcomes (see the Perspective by de Alwis and Ooi). They found that DENV infection induced specific increases in IgG1 afucosylation, and levels of afucosylated IgG1 could indeed predict dengue disease severity, making IgG1 fucosylation status a potentially useful prognostic tool for the treatment of dengue patients. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abc7303, this issue p. <jats:related-article issue="6546" page="1102" related-article-type="in-this-issue" vol="372">1102</jats:related-article> ; see also abj0435, p. <jats:related-article issue="6546" page="1041" related-article-type="in-this-issue" vol="372">1041</jats:related-article> </jats:p>

<jats:title>Mysterious mass extinction</jats:title> <jats:p>The term “shark” inspires predictable images of stealthy and streamlined marine predators that are key components of modern ecosystems. Studying shark teeth buried in deep sea sediment, Sibert and Rubin reveal that current shark diversity is a small remnant of a much larger array of forms that were decimated by a previously unidentified major ocean extinction event (see the Perspective by Pimiento and Pyenson). The extinction led to a reduction in shark diversity by more than 70% and an almost complete loss in total abundance. There is no known climatic and/or environmental driver of this extinction, and its cause remains a mystery. Modern shark forms began to diversify within 2 to 5 million years after the extinction, but they represent only a minor sliver of what sharks once were.</jats:p> <jats:p> <jats:italic>Science</jats:italic> , aaz3549, this issue p. <jats:related-article issue="6546" page="1105" related-article-type="in-this-issue" vol="372">1105</jats:related-article> ; see also abj2088, p. <jats:related-article issue="6546" page="1036" related-article-type="in-this-issue" vol="372">1036</jats:related-article> </jats:p>

<jats:title>A public anti-COVID antibody repertoire</jats:title> <jats:p> Most analyses of the antibody responses induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have focused on antibodies cloned from memory B cells. This approach has led researchers to conclude that neutralizing antibodies (nAbs) primarily target the receptor-binding domain (RBD) of the virus's spike protein. Voss <jats:italic>et al.</jats:italic> took a different approach, using proteomic deconvolution of the serum immunoglobulin G antibody repertoire from four COVID-19 convalescent patients. They found that the nAb response was largely directed against epitopes such as the N-terminal domain (NTD), which lie outside the RBD. Several of these nAbs were shared among donors and targeted an NTD epitope that is frequently mutated by variants of concern. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abg5268, this issue p. <jats:related-article issue="6546" page="1108" related-article-type="in-this-issue" vol="372">1108</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>