Catálogo de publicaciones - revistas

<jats:title>Climate filters dominant species</jats:title> <jats:p> The transition between the Eocene and Oligocene periods was marked by distinct cooling. Because primate species are particularly susceptible to cold, this change in climate drove a retraction of primates globally. After this transition, anthropoid primates were dominant in Afro-Arabian regions, but little has been known about primate reestablishment in Asia. Ni <jats:italic>et al.</jats:italic> describe 10 previously unknown primates found in Yunnan Province in China that show that primates took a different path in Asia. Instead of anthropoids, strepsirrhine (lemur-like) primates were dominant. It is still unknown whether this difference was due to the environment or chance. </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="6286" page="673" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf2107">673</jats:related-article> </jats:p>

<jats:title>Cosmic rays from a nearby supernova</jats:title> <jats:p> Supernova explosions produce unstable isotopes, spreading them through space in the form of cosmic rays. Binns <jats:italic>et al.</jats:italic> used NASA's Advanced Composition Explorer spacecraft to search for previously undetected traces of <jats:sup>60</jats:sup> Fe in cosmic rays passing through the solar system. Seventeen years of observations detected just 15 <jats:sup>60</jats:sup> Fe nuclei—a small but statistically significant number. Because <jats:sup>60</jats:sup> Fe is radioactive, with a half-life of 2.6 million years, these nuclei must have formed relatively recently in a nearby supernova. The most likely candidates are massive stars in the Scorpius-Centaurus association. </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="6286" page="677" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad6004">677</jats:related-article> </jats:p>

<jats:title>Building with designed proteins</jats:title> <jats:p> General design principles for protein interaction specificity are challenging to extract. DNA nanotechnology, on the other hand, has harnessed the limited set of hydrogen-bonding interactions from Watson-Crick base-pairing to design and build a wide range of shapes. Protein-based materials have the potential for even greater geometric and chemical diversity, including additional functionality. Boyken <jats:italic>et al.</jats:italic> designed a class of protein oligomers that have interaction specificity determined by modular arrays of extensive hydrogen bond networks (see the Perspective by Netzer and Fleishman). They use the approach, which could one day become programmable, to build novel topologies with two concentric rings of helices. </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="6286" page="680" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad8865">680</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6286" page="657" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf7599">657</jats:related-article> </jats:p>

<jats:title>Building new proteins from the old</jats:title> <jats:p> Proteins are the workhorses of biology. Designing new, stable proteins with functions desirable in biotechnology or biomedicine remains challenging. Jacobs <jats:italic>et al.</jats:italic> developed a computational method called SEWING that designs proteins using pieces of existing structures (see the Perspective by Netzer and Fleishman). The new proteins can contain structural features such as pockets or grooves that are required for function. The solved structures of two designed proteins agreed well with the design models. The method allows rapid design of a diverse set of structures that will facilitate functional design. </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="6286" page="687" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad8036">687</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6286" page="657" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf7599">657</jats:related-article> </jats:p>

<jats:title>Rapid mixing to race past rearrangement</jats:title> <jats:p> Chemistry relies on encounters between reactive partners. Sometimes one of the partners changes shape during the wait, spoiling the desired outcome. Kim <jats:italic>et al.</jats:italic> designed a microfluidic device to keep such botched encounters from happening. The device operates at low temperatures to keep individual reactants from isomerizing. It also achieves fast flow rates to maximize encounters between reactants on a microsecond time scale. The authors showcase the device by achieving bimolecular carbon-carbon coupling before one of the reagents can undergo a Fries rearrangement that would shift a neighboring group to the coupling site. </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="6286" page="691" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf1389">691</jats:related-article> </jats:p>

<jats:title>Filtering out the effect of large floods</jats:title> <jats:p>Large floods should seemingly influence the depth and width of rivers. Phillips and Jerolmack, however, suggest that the self-organization of bedrock river channels blunts the impact of extreme rainfall events. River channel geometries from a wide range of course-grained rivers across the United States show that larger floods have very limited additional impact on channel geometry. River channel sculpting does increase as flood size increases, but the effect is most pronounced for moderate floods. This relationship may explain the long-term stability of rivers across shifts in climate.</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="6286" page="694" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad3348">694</jats:related-article> </jats:p>

<jats:title>Growing patterned rectangular objects</jats:title> <jats:p> The growth of patterned objects usually requires a template to aid the positioning of multiple materials. Qiu <jats:italic>et al.</jats:italic> used the seeded growth of a crystallizable block copolymer and a homopolymer to produce highly uniform rectangular structures (see the Perspective by Ballauff). Chemical etching, or dissolution, of uncross-linked regions of the rectangular structures produced perforated platelet micelles. The sequential addition of different blends and cross-linking/dissolution strategies allowed the formation of well-defined hollow rectangular micelles, which can be functionalized in a variety of ways. </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="6286" page="697" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad9521">697</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6286" page="656" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf4930">656</jats:related-article> </jats:p>