Catálogo de publicaciones - revistas

<jats:title>Architecture of DNA-organizing complex</jats:title> <jats:p> The highly conserved mammalian CTC1-STN1-TEN1 (CST) complex is critical for genome stability and telomere maintenance. Lim <jats:italic>et al.</jats:italic> solved the structure of the human CST complex using cryo–electron microscopy. CST forms an unprecedented and substantial decameric supercomplex triggered by telomeric single-stranded binding. This decameric form with single-stranded DNA–binding capacity of up to 10 telomeric repeats, suggested the possibility of CST organizing telomere overhangs into compact and restrictive structures in a manner similar to the nucleosome's organization of double-stranded DNA. This work provides a platform for understanding the mechanisms of various CST functions. </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="6495" page="1081" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz9649">1081</jats:related-article> </jats:p>

<jats:title>Watching electrons swarm ammonia</jats:title> <jats:p> Liquid ammonia is unusual in its capacity to host electrons in stable solution, with vivid blue and bronze colors signifying the low- and high-concentration regimes, respectively. Buttersack <jats:italic>et al.</jats:italic> used photoelectron spectroscopy and accompanying theoretical simulations to track the precise energetic changes that ensued as steadily rising quantities of electrons were introduced by dissolved lithium, sodium, or potassium (see the Perspective by Isborn). The results point to a gradual transition from the dilute electrolyte solution of paired dielectrons to the more delocalized metallic structure at the highest concentrations. </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="6495" page="1086" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz7607">1086</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6495" page="1056" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb9717">1056</jats:related-article> </jats:p>

<jats:title>Improving ionic thermoelectrics</jats:title> <jats:p> Using ions as charge carriers in thermoelectric devices usually requires using either thermal diffusion or redox reactions at two electrodes with different temperatures. Han <jats:italic>et al.</jats:italic> leveraged both of these strategies to develop a gelatin-based ionic thermoelectric device that uses alkali salts and an iron-based redox couple to generate a large thermopower. This device is capable of generating useful amounts of energy from body heat. </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="6495" page="1091" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz5045">1091</jats:related-article> </jats:p>

<jats:title>Hydrogenations that tolerate N–O bonds</jats:title> <jats:p> Catalysts that add hydrogen to carbon-carbon, carbon-nitrogen, and carbon-oxygen double bonds are among the most widely used in synthetic chemistry. They are particularly adept at delivering just one of two mirror-image products. However, they may also target adjacent bonds in the compound that would be better left intact. Mas-Roselló <jats:italic>et al.</jats:italic> report that an iridium catalyst paired with a strong acid can hydrogenate C=N bonds without disturbing a weak N–O bond on the same nitrogen center. The reactions proceed at room temperature with high enantioselectivity. </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="6495" page="1098" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb2559">1098</jats:related-article> </jats:p>

<jats:title>Perfluorocarbons' path into soils</jats:title> <jats:p> Covering carbon chains with fluorines has produced a variety of useful nonstick coatings. However, growing concern about the toxicity and extraordinary environmental persistence of the underlying compounds is spurring a search for alternatives. The precise structure of these next-generation alternatives often remains a trade secret. Washington <jats:italic>et al.</jats:italic> sampled soils in New Jersey and then used mass spectrometry to assign plausible structures—incorporating chlorine and ether segments into the CF <jats:sub>2</jats:sub> chain—to compounds that appear to have emanated from their manufacture (see the Policy Forum by Gold and Wagner). The data can inform in-depth studies of these compounds' environmental transport and persistence. </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="6495" page="1103" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aba7127">1103</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6495" page="1066" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abc1250">1066</jats:related-article> </jats:p>

<jats:title>Making blind retinas see again</jats:title> <jats:p> Photoreceptor degeneration is an important cause of blindness. Nelidova <jats:italic>et al.</jats:italic> used tunable, near-infrared sensors to render diseased photoreceptors light sensitive again (see the Perspective by Franke and Vlasits). Gold nanorods capable of detecting infrared light were coupled with an antibody to temperature-sensitive ion channels. When the nanorods absorbed light and converted it into heat, the coupled ion channels were gated by infrared light. In a mouse model of retinal degeneration, these ion channels were successfully targeted to cone photoreceptors, and responses to near infrared light could be detected. In the primary visual cortex, more cells responded to near-infrared stimuli in mice expressing these ion channels than in controls. By changing the length of the gold nanorods, the system could be tuned to different infrared wavelengths. </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="6495" page="1108" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz5887">1108</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6495" page="1057" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abc2294">1057</jats:related-article> </jats:p>

<jats:title>Topological insulators in the spotlight</jats:title> <jats:p> In addition to having an insulating interior while at the same time supporting conducting surface states, topological insulators have many other interesting properties. Higher-order topological insulating states, where regions of interest are along edges and at corners, have been difficult to identify unambiguously. Peterson <jats:italic>et al.</jats:italic> developed a theoretical framework to help identify and characterize these exotic states, including a new topological marker—the fractional charge density—that can be used to detect topological states of matter when the spectroscopic probe of gapless surface states is not accessible. The agreement between experimental work and theory is encouraging for applicability to other topological platforms. </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="6495" page="1114" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aba7604">1114</jats:related-article> </jats:p>

<jats:title>Mangroves under sea level rise</jats:title> <jats:p> The rate of sea level rise has doubled from 1.8 millimeters per year over the 20th century to ∼3.4 millimeters per year in recent years. Saintilan <jats:italic>et al.</jats:italic> investigated the likely effects of this increasing rate of rise on coastal mangrove forest, a tropical ecosystem of key importance for coastal protection (see the Perspective by Lovelock). They reviewed data on mangrove accretion 10,000 to 7000 years before present, when the rate of sea level rise was even higher than today as a result of glacial ice melt. Their analysis suggests an upper threshold of 7 millimeters per year as the maximum rate of sea level rise associated with mangrove vertical development, beyond which the ecosystem fails to keep up with the change. Under projected rates of sea level rise, they predict that a deficit between accretion and sea level rise is likely to commence in the next 30 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="6495" page="1118" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aba2656">1118</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6495" page="1050" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abc3735">1050</jats:related-article> </jats:p>