Catálogo de publicaciones - revistas

<jats:title>How to make opposites compatible</jats:title> <jats:p> Polyethylene (PE) and isotactic polypropylene ( <jats:italic>i</jats:italic> PP) are the two most widely used commodity plastics and thus make up a large fraction of the waste stream. However, the two plastics will not mix together, which limits options for dealing with mixed waste and decreases the value of recycled products. Eagan <jats:italic>et al.</jats:italic> report the synthesis of multiblock copolymers of <jats:italic>i</jats:italic> PP and PE by using a selective polymer initiator (see the Perspective by Creton). The high-molecular-weig ht blocks could be used to reinforce the interface between <jats:italic>i</jats:italic> PP and PE and allow blending of the two polymers. </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="6327" page="814" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aah5744">814</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6327" page="797" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aam5803">797</jats:related-article> </jats:p>

<jats:title>Spinning up an extragalactic neutron star</jats:title> <jats:p> Ultraluminous x-ray sources (ULXs) are strange objects in other galaxies that cannot be explained by conventional accretion onto stellar-mass objects. This has led to exotic interpretations, such as the long-sought intermediate-mass black holes. Israel <jats:italic>et al.</jats:italic> observed a ULX in the nearby galaxy NGC 5907 and found that it is instead a neutron star. The spinning neutron star is accreting material so fast that its spin period is quickly accelerating. The only way that it can consume enough material to explain these properties is if it has a strong multipolar magnetic field. </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="6327" page="817" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aai8635">817</jats:related-article> </jats:p>

<jats:title>How will this molecule smell?</jats:title> <jats:p> We still do not understand what a given substance will smell like. Keller <jats:italic>et al.</jats:italic> launched an international crowd-sourced competition in which many teams tried to solve how the smell of a molecule will be perceived by humans. The teams were given access to a database of responses from subjects who had sniffed a large number of molecules and been asked to rate each smell across a range of different qualities. The teams were also given a comprehensive list of the physical and chemical features of the molecules smelled. The teams produced algorithms to predict the correspondence between the quality of each smell and a given molecule. The best models that emerged from this challenge could accurately predict how a new molecule would smell. </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="6327" page="820" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aal2014">820</jats:related-article> </jats:p>

<jats:title>Resistance on a background of tolerance</jats:title> <jats:p> Bacteria survive antibiotic exposure either because they are quiescent when antibiotics are around in the highest concentrations (i.e., tolerance) or because they acquire active biochemical resistance mechanisms (i.e., resistance). Both tolerance and resistance involve the acquisition of mutations from the wild type. Levin-Reisman <jats:italic>et al.</jats:italic> used in vitro evolution experiments to show that populations of bacteria that become genetically resistant to the antibiotic ampicillin most quickly do so on a background of tolerance mutations (see the Perspective by Lewis and Shan). Because the probability of a tolerant organism surviving is higher, it has a greater chance of subsequently acquiring resistance mutations. Tolerance is often overlooked in the clinic but should in future be screened for and targeted more precisely to reduce the rates of acquired resistance. </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="6327" page="826" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aaj2191">826</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6327" page="796" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aam7926">796</jats:related-article> </jats:p>

<jats:title>What's in a fold?</jats:title> <jats:p> Bacterially secreted peptides known as PSMs (phenol-soluble modulins) stimulate inflammatory responses, lyse human cells, and contribute to biofilm structuring. PSMα3 is a virulent 22-residue amyloid peptide secreted by <jats:italic>Staphylococcus aureus.</jats:italic> Tayeb-Fligelman <jats:italic>et al.</jats:italic> present a high-resolution structure encompassing the full length of the amyloid's sequence. This structure reveals an unexpected departure from the common amyloid cross-β folded architecture. Instead, PSMα3 forms amphipathic α-helices that are folded to stack perpendicular to the fibril axis into sheets. This unusual cross-α structure was important for fibril toxicity. </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="6327" page="831" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aaf4901">831</jats:related-article> </jats:p>

<jats:title>Very clever bees use tools</jats:title> <jats:p> One hallmark of cognitive complexity is the ability to manipulate objects with a specific goal in mind. Such “tool use” at one time was ascribed to humans alone, but then to primates, next to marine mammals, and later to birds. Now we recognize that many species have the capacity to envision how a particular object might be used to achieve an end. Loukola <jats:italic>et al.</jats:italic> extend this insight to invertebrates. Bumblebees were trained to see that a ball could be used to produce a reward. These bees then spontaneously rolled the ball when given the 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="6327" page="833" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aag2360">833</jats:related-article> </jats:p>

<jats:title>Shining a light on cell signaling</jats:title> <jats:p> Protein kinases are proteins that are used to transmit signals within cells. Zhou <jats:italic>et al.</jats:italic> engineered diverse kinases so that they could be switched on and off with visible light. They modified the fluorescent protein Dronpa so that instead of being tetrameric, it dimerized in violet light and dissociated in cyan light, and they fused two copies to representatives from different families of kinases. The engineered kinases could be photo-switched with spatial and temporal precision and were successfully used to study a variety of signaling pathways. </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="6327" page="836" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aah3605">836</jats:related-article> </jats:p>

<jats:title>Faulty blood cells and heart disease</jats:title> <jats:p> Recent studies have shown that elderly people's blood cells often harbor mutations in genes encoding certain epigenetic regulators. These mutations can lead to clonal expansion of the mutant blood cells, which increases the risk of blood cancers and cardiovascular disease. Fuster <jats:italic>et al.</jats:italic> generated a mouse model to investigate how one of these genes, <jats:italic>Tet2</jats:italic> , affects atherosclerosis development (see the Perspective by Zhu <jats:italic>et al.</jats:italic> ). They found that the disease progressed more rapidly in mice transplanted with <jats:italic>Tet2</jats:italic> -deficient bone marrow cells. This was due to increased secretion of interleukin-1β by <jats:italic>Tet2</jats:italic> -deficient macrophages in a process that depended on the action of inflammasomes. </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="6327" page="842" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aag1381">842</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6327" page="798" related-article-type="in-this-issue" vol="355" xlink:href="10.1126/science.aam7939">798</jats:related-article> </jats:p>

<jats:p> The 2017 Gordon Research Conference schedule was published on pages 848 to 870 of this issue of the print version of <jats:italic>Science</jats:italic> . The current schedule can also be found online at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.grc.org/">www.grc.org/</jats:ext-link> . </jats:p>