Catálogo de publicaciones - revistas

<jats:title>Separating one organic from another</jats:title> <jats:p>Separating closely related organic molecules is a challenge (see the Perspective by Lin).The separation of acetylene from ethylene is needed in high-purity polymer production. Cui et al. developed a copper-based metal-organic framework with hexafluorosilicate and organic linkers designed to have a high affinity for acetylene. These materials, which capture four acetylene molecules in each pore, successfully separated acetylene from mixtures with ethylene. Propane and propylene are both important feedstock chemicals. Their physical and chemical similarity, however, requires energy-intense processes to separate them. Cadiau et al. designed a fluorinated porous metal-organic framework material that selectively adsorbed propylene, with the complete exclusion of propane.</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="6295" page="141" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf2458">141</jats:related-article> and <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6295" page="137" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf6323">137</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6295" page="121" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aag2267">121</jats:related-article> </jats:p>

<jats:title>Separating one organic from another</jats:title> <jats:p>Separating closely related organic molecules is a challenge (see the Perspective by Lin).The separation of acetylene from ethylene is needed in high-purity polymer production. Cui et al. developed a copper-based metal-organic framework with hexafluorosilicate and organic linkers designed to have a high affinity for acetylene. These materials, which capture four acetylene molecules in each pore, successfully separated acetylene from mixtures with ethylene. Propane and propylene are both important feedstock chemicals. Their physical and chemical similarity, however, requires energy-intense processes to separate them. Cadiau et al. designed a fluorinated porous metal-organic framework material that selectively adsorbed propylene, with the complete exclusion of propane.</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="6295" page="141" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf2458">141</jats:related-article> and <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6295" page="137" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf6323">137</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6295" page="121" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aag2267">121</jats:related-article> </jats:p>

<jats:title>Olefins enlisted to attack ketones</jats:title> <jats:p> The reaction of C=O groups in ketones with organometallic compounds is a common method to form carbon-carbon bonds. One drawback to this approach, however, is that the organometallics, such as magnesium-derived Grignard reagents, are difficult to handle and susceptible to side reactions. Yang <jats:italic>et al.</jats:italic> present an alternative method, whereby a copper catalyst activates stable olefins (C=C double bonds) to attack ketones at room temperature. An added silane functions as a reducing agent, and a chiral phosphine ligand renders the reaction highly enantioselective. </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="6295" page="144" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf7720">144</jats:related-article> </jats:p>

<jats:title>Hot single-atom catalysts</jats:title> <jats:p> For heterogeneous catalysts made from precious metal nanoparticles adsorbed on metal oxides, high temperatures are the enemy. The metal atoms become mobile and the small particles grow larger, causing a loss in surface area and hence in activity. Jones <jats:italic>et al.</jats:italic> turned this process to their advantage and used these mobile species to create single-atom platinum catalysts. The platinum on alumina supported transfers in air at 800°C to ceria supports to form highly active catalysts with isolated metal cations. </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="6295" page="150" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf8800">150</jats:related-article> </jats:p>

<jats:p>Animal and robot experiments explore the use of a tail in aiding terrestrial locomotion.</jats:p>

<jats:title>Swim into the light</jats:title> <jats:p> A bio-inspired swimming robot that mimics a ray fish can be guided by light. Park <jats:italic>et al.</jats:italic> built a 1/10th-scale version of a ray fish with a microfabricated gold skeleton and a rubber body powered by rat heart muscle cells. The cardiomyocytes were genetically engineered to respond to light cues, so that the undulatory movements propelling the robot through water would follow a light source. </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="6295" page="158" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf4292">158</jats:related-article> </jats:p>

<jats:title>Resolving a network of hubs</jats:title> <jats:p> Graphs are a pervasive tool for modeling and analyzing network data throughout the sciences. Benson <jats:italic>et al.</jats:italic> developed an algorithmic framework for studying how complex networks are organized by higher-order connectivity patterns (see the Perspective by Pržulj and Malod-Dognin). Motifs in transportation networks reveal hubs and geographical elements not readily achievable by other methods. A motif previously suggested as important for neuronal networks is part of a “rich club” of subnetworks. </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="6295" page="163" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aad9029">163</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6295" page="123" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aah3449">123</jats:related-article> </jats:p>

<jats:title>Location, location, S-acylation</jats:title> <jats:p> Cellulose synthase is a large, multisubunit machine that “swims” along the plant cell membrane as it spins out cellulose fibers. Kumar <jats:italic>et al.</jats:italic> show that the cellulose synthase complex is heavily modified through S-acylation. Subsets of the acylation sites were required for the complex to integrate into the plasma membrane. A single functional complex could bear as many as 100 modification sites, potentially changing its biophysical characteristics and helping it to associate with the membrane. </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="6295" page="166" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf4009">166</jats:related-article> </jats:p>