Catálogo de publicaciones - revistas

<jats:title>Improving the stability of perovskite solar cells</jats:title> <jats:p> Inorganic-organic perovskite solar cells have poor long-term stability because ultraviolet light and humidity degrade these materials. Bella <jats:italic>et al.</jats:italic> show that coating the cells with a water-proof fluorinated polymer that contains pigments to absorb ultraviolet light and re-emit it in the visible range can boost cell efficiency and limit photodegradation. The performance and stability of inorganic-organic perovskite solar cells are also limited by the size of the cations required for forming a correct lattice. Saliba <jats:italic>et al.</jats:italic> show that the rubidium cation, which is too small to form a perovskite by itself, can form a lattice with cesium and organic cations. Solar cells based on these materials have efficiencies exceeding 20% for over 500 hours if given environmental protection by a polymer coating. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue pp. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6309" page="203" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah4046">203</jats:related-article> and <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6309" page="206" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah5557">206</jats:related-article> </jats:p>

<jats:title>Two roads diverged in a yellow photolyase</jats:title> <jats:p> Photolyase enzymes repair DNA that has been damaged by ultraviolet sunlight. The repair process begins when blue light absorption by a cofactor drives an electron transfer step. Zhang <jats:italic>et al.</jats:italic> applied ultrafast absorption spectroscopy to study the dynamics of this step. A bifurcation in the electron transfer pathway favors a direct tunneling mechanism in the prokaryotic enzymes and a two-step hopping mechanism in the eukaryotic variety. This difference explains the higher repair quantum yield seen in prokaryotes. </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="6309" page="209" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah6071">209</jats:related-article> </jats:p>

<jats:title>Migration of influenza in wild birds</jats:title> <jats:p>Virus surveillance in wild birds could offer an early warning system that, combined with adequate farm hygiene, would lead to effective influenza control in poultry units. The Global Consortium for H5N8 and Related Influenza Viruses found that the H5 segment common to the highly pathogenic avian influenza viruses readily reassorts with other influenza viruses (see the Perspective by Russell). H5 is thus a continual source of new pathogenic variants. These data also show that the H5N8 virus that recently caused serious outbreaks in European and North American poultry farms came from migrant ducks, swans, and geese that meet at their Arctic breeding grounds. Because the virus is so infectious, culling wild birds is not an effective control measure.</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="6309" page="213" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf8852">213</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6309" page="174" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaj1646">174</jats:related-article> </jats:p>

<jats:title>A consensus in Europe about asylum seekers</jats:title> <jats:p> Violent conflicts between groups often generate large numbers of noncombatant refugees. Bansak <jats:italic>et al.</jats:italic> surveyed western European attitudes toward such asylum seekers. They found that voters favor applicants who will contribute to the recipient country's economy, who have suffered severe physical or mental distress rather than economic hardship, and who are Christian rather than Muslim. These preferences are similar across countries and independent of the voters' personal characteristics. </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="6309" page="217" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aag2147">217</jats:related-article> </jats:p>

<jats:title>Microbes make methane from coal</jats:title> <jats:p> Methane associated with coal beds is an important global resource of natural gas. Much of the methane in coal comes from microbial methanogenesis. Mayumi <jats:italic>et al.</jats:italic> characterized a strain of <jats:italic>Methermicoccus shengliensis</jats:italic> that, unexpectedly, is capable of making methane from the dozens of methoxylated aromatic compounds found in a variety of coal types (see the Perspective by Welte). Isotope tracer experiments showed that this organism could also incorporate carbon dioxide into methane. </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="6309" page="222" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf8821">222</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6309" page="184" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aai8101">184</jats:related-article> </jats:p>

<jats:title>An impactful event</jats:title> <jats:p> Glassy silica spherules have been found in marine sediments from three sites across a wide area off the Atlantic coast of the United States, near the stratigraphic level of the Paleocene-Eocene boundary. The characteristics of these specimens are consistent with those of microtektites associated with extraterrestrial impact events. This discovery by Schaller <jats:italic>et al.</jats:italic> is evidence of an impact event at the time of the Paleocene-Eocene Thermal Maximum, a period during which global temperatures increased rapidly and the carbon cycle was substantially perturbed. </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="6309" page="225" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf5466">225</jats:related-article> </jats:p>

<jats:title>Phosphorylation and fungal evolution</jats:title> <jats:p> Phosphorylation after transcription modifies the activity of proteins. To understand how phosphorylation sites have evolved, Studer <jats:italic>et al.</jats:italic> studied a range of fungal species (see the Perspective by Matalon <jats:italic>et al.</jats:italic> ). Only a few sites were apparently present in the common ancestor of all 18 species investigated. Evolutionary age appeared to predict the potential functional importance of specific conserved phosphosites. </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="6309" page="229" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf2144">229</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6309" page="176" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aai8833">176</jats:related-article> </jats:p>

<jats:title>A function for multisite phosphorylation</jats:title> <jats:p> Many transcription factors are regulated by phosphorylation on multiple residues. Mylona <jats:italic>et al.</jats:italic> analyzed multisite phosphorylation in the transcription factor Elk-1 and showed that it may protect against excessive activation (see the Perspective by Whitmarsh and Davis). Phosphorylation by the kinase ERK2 occurred at eight sites, but the sites were phosphorylated at different rates. Those that were phosphorylated more quickly promoted transcriptional activation. Those that were phosphorylated more slowly dampened excessive activation by ERK2s without needing a phosphatase or any other negative regulatory component. </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="6309" page="233" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aad1872">233</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6309" page="179" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aai9381">179</jats:related-article> </jats:p>

<jats:title>A DNA vaccine candidate for Zika</jats:title> <jats:p> The ongoing Zika epidemic in the Americas and the Caribbean urgently needs a protective vaccine. Two DNA vaccines composed of the genes that encode the structural premembrane and envelope proteins of Zika virus have been tested in monkeys. Dowd <jats:italic>et al.</jats:italic> show that two doses of vaccine given intramuscularly completely protected 17 of 18 animals against Zika virus challenge. A single low dose of vaccine was not protective but did reduce viral loads. Protection correlated with serum antibody neutralizing activity. Phase I clinical trials testing these vaccines are already ongoing. </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="6309" page="237" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aai9137">237</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>