Catálogo de publicaciones - revistas

<jats:title>Crowdsourcing a chromophore</jats:title> <jats:p> Photoredox catalysis is widely used to accelerate chemical reactions by channeling the energy in visible light. However, most implementations rely on expensive chromophores to absorb light. Fu <jats:italic>et al.</jats:italic> now show that a pair of cheap components acting in concert can induce these reactions, despite not being strong visible absorbers individually. The combination of sodium iodide and triphenylphosphine allowed photoinduced electron transfer to catalyze a variety of alkylations. </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="6434" page="1429" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav3200">1429</jats:related-article> </jats:p>

<jats:title>Magnetic building blocks in two dimensions</jats:title> <jats:p> Artificial magnetic structures can offer a variety of functionalities in spintronics devices. Luo <jats:italic>et al.</jats:italic> engineered magnetic domains in Pt/Co/AlO <jats:sub> <jats:italic>x</jats:italic> </jats:sub> trilayers that had alternating in-plane and out-of-plane magnetizations. The regions interacted laterally through the so-called Dzyaloshinskii-Moriya interaction, which determined the relative sign and orientation of the magnetization in adjacent domains. Using the coupling between the domains, the researchers were able to engineer more-complex magnetic structures such as skyrmions and frustrated magnets. </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="6434" page="1435" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aau7913">1435</jats:related-article> </jats:p>

<jats:title>The right hand lines up vinyl ethers</jats:title> <jats:p>Well-optimized catalysts produce vast quantities of isotactic polypropylene, in which the side chains all face the same way. Add an oxygen into the monomer, though, and that degree of uniformity becomes harder to enforce. Teator and Leibfarth report a general protocol to polymerize a variety of such vinyl ethers isotactically (see the Perspective by Foster and O'Reilly). They rely on a chiral phosphoric acid in combination with a titanium Lewis acid to bias the monomer orientation during cationic polymerization. The resulting polymers show promising adhesive properties.</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="6434" page="1439" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw1703">1439</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6434" page="1394" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw9863">1394</jats:related-article> </jats:p>

<jats:title>Reward and the map in the brain</jats:title> <jats:p> Recent findings suggest a more complex role of grid cells in the brain than simply coding for space. The grid map in the entorhinal cortex, which is responsible for encoding spatial information, is not as rigid as originally thought and can be distorted by environmental modifications (see the Perspective by Quian Quiroga). Butler <jats:italic>et al.</jats:italic> compared grid cell coding during a free-foraging task and a spatial memory task in rats. They discovered that entorhinal spatial maps restructure to incorporate the location of a learned reward. Boccara <jats:italic>et al.</jats:italic> tested the influence of behaviorally relevant information on the cognitive map that emerges from grid cell firing in the rat medial entorhinal cortex. They found that grid cells participate in neural coding of the goal locality, not the whole environment. </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="6434" page="1447" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav5297">1447</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6434" page="1443" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav4837">1443</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6434" page="1388" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw8829">1388</jats:related-article> </jats:p>

<jats:title>Reward and the map in the brain</jats:title> <jats:p> Recent findings suggest a more complex role of grid cells in the brain than simply coding for space. The grid map in the entorhinal cortex, which is responsible for encoding spatial information, is not as rigid as originally thought and can be distorted by environmental modifications (see the Perspective by Quian Quiroga). Butler <jats:italic>et al.</jats:italic> compared grid cell coding during a free-foraging task and a spatial memory task in rats. They discovered that entorhinal spatial maps restructure to incorporate the location of a learned reward. Boccara <jats:italic>et al.</jats:italic> tested the influence of behaviorally relevant information on the cognitive map that emerges from grid cell firing in the rat medial entorhinal cortex. They found that grid cells participate in neural coding of the goal locality, not the whole environment. </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="6434" page="1447" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav5297">1447</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6434" page="1443" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav4837">1443</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6434" page="1388" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw8829">1388</jats:related-article> </jats:p>

<jats:title>More than just numbers</jats:title> <jats:p> We often frame negative human impacts on animal species in terms of numbers of individuals reduced or numbers of regions from which species are absent. However, human activities are likely affecting species in more complex ways than these figures can capture. Kühl <jats:italic>et al.</jats:italic> studied behavioral and cultural diversity in our closest relative, the chimpanzee. They found that human-mediated disturbance is reducing these complex traits. Human influence thus goes well beyond simple loss of populations or species, leading to behavioral change even where populations persist. </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="6434" page="1453" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aau4532">1453</jats:related-article> </jats:p>

<jats:title>Speeding up stomatal responses</jats:title> <jats:p> A plant's cellular metabolism rapidly adjusts to changes in light conditions, but its stomata—pores that allow gas exchange in leaves—are slower to respond. Because of the lagging response, photosynthesis is less efficient, and excess water is lost through the open pores. Papanatsiou <jats:italic>et al.</jats:italic> introduced a blue light–responsive ion channel into stomata of the small mustard plant <jats:italic>Arabidopsis.</jats:italic> The channel increased the rate of stomata opening and closing in response to light. The engineered plants produced more biomass, especially in the fluctuating light conditions typical of outdoor growth. </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="6434" page="1456" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw0046">1456</jats:related-article> </jats:p>

<jats:title>The demise of amphibians?</jats:title> <jats:p> Rapid spread of disease is a hazard in our interconnected world. The chytrid fungus <jats:italic>Batrachochytrium dendrobatidis</jats:italic> was identified in amphibian populations about 20 years ago and has caused death and species extinction at a global scale. Scheele <jats:italic>et al.</jats:italic> found that the fungus has caused declines in amphibian populations everywhere except at its origin in Asia (see the Perspective by Greenberg and Palen). A majority of species and populations are still experiencing decline, but there is evidence of limited recovery in some species. The analysis also suggests some conditions that predict resilience. </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="6434" page="1459" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav0379">1459</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6434" page="1386" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aax0002">1386</jats:related-article> </jats:p>

<jats:title>Gene expression at fine scale</jats:title> <jats:p> Mapping gene expression at the single-cell level within tissues remains a technical challenge. Rodriques <jats:italic>et al.</jats:italic> developed a method called Slide-seq, whereby RNA was spatially resolved from tissue sections by transfer onto a surface covered with DNA-barcoded beads. Applying Slide-seq to regions of a mouse brain revealed spatial gene expression patterns in the Purkinje layer of the cerebellum and axes of variation across Purkinje cell compartments. The authors used this method to dissect the temporal evolution of cell type–specific responses in a mouse model of traumatic brain injury. </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="6434" page="1463" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw1219">1463</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>