Catálogo de publicaciones - revistas

<jats:title>Interactions that slow protein folding</jats:title> <jats:p> As proteins fold, they diffuse over an energy barrier that separates unfolded and folded states. The transition path defines how a single protein crosses the barrier and so contains key information on the mechanism of folding. Transition paths have not yet been experimentally observed, but Chung <jats:italic>et al.</jats:italic> have discovered which structural features of the protein affect the duration of the transition. As the protein folds, non-native salt bridges form and break, slowing diffusion along the transition path. </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="6255" page="1504" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab1369">1504</jats:related-article> </jats:p>

<jats:title>Visualizing edge states in atomic systems</jats:title> <jats:p> Visualizing edge states in atomic systems Simulating the solid state using ultracold atoms is an appealing research approach. In solids, however, the charged electrons are susceptible to an external magnetic field, which curves their trajectories and makes them skip along the edge of the sample. To observe this phenomenon with cold atoms requires an artificial magnetic field to have a similar effect on the neutral atoms (see the Perspective by Celi and Tarruell). Stuhl <jats:italic>et al.</jats:italic> obtained skipping orbits with bosonic atoms using a lattice that consisted of an array of atoms in one direction and three internal atomic spin states in the other. In a complementary experiment, Mancini <jats:italic>et al.</jats:italic> observed similar physics with fermionic atoms. </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="6255" page="1514" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa8515">1514</jats:related-article> and <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6255" page="1510" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa8736">1510</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6255" page="1450" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac7605">1450</jats:related-article> </jats:p>

<jats:title>Visualizing edge states in atomic systems</jats:title> <jats:p> Visualizing edge states in atomic systems Simulating the solid state using ultracold atoms is an appealing research approach. In solids, however, the charged electrons are susceptible to an external magnetic field, which curves their trajectories and makes them skip along the edge of the sample. To observe this phenomenon with cold atoms requires an artificial magnetic field to have a similar effect on the neutral atoms (see the Perspective by Celi and Tarruell). Stuhl <jats:italic>et al.</jats:italic> obtained skipping orbits with bosonic atoms using a lattice that consisted of an array of atoms in one direction and three internal atomic spin states in the other. In a complementary experiment, Mancini <jats:italic>et al.</jats:italic> observed similar physics with fermionic atoms. </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="6255" page="1514" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa8515">1514</jats:related-article> and <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6255" page="1510" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa8736">1510</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6255" page="1450" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac7605">1450</jats:related-article> </jats:p>

<jats:title>Flat perovskite crystals</jats:title> <jats:p> Bulk crystals and thick films of inorganic-organic perovskite materials such as CH <jats:sub>3</jats:sub> NH <jats:sub>3</jats:sub> PbI <jats:sub>3</jats:sub> have shown promise as active material for solar cells. Dou <jats:italic>et al.</jats:italic> show that thin films—a single unit cell or a few unit cells thick—of a related composition, (C <jats:sub>4</jats:sub> H <jats:sub>9</jats:sub> NH <jats:sub>3</jats:sub> ) <jats:sub>2</jats:sub> PbBr <jats:sub>4</jats:sub> , form squares with edges several micrometers long. These materials exhibit strong and tunable blue photoluminescence. </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="6255" page="1518" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac7660">1518</jats:related-article> </jats:p>

<jats:title>Placing bounds on gravitational wave detection</jats:title> <jats:p> Gravitational waves are expected to be generated by the interaction of the massive bodies in black-hole binary systems. As gravitational waves distort spacetime, it should be possible to verify their existence as they interfere with the pulses emitted by millisecond pulsars. However, after monitoring 24 pulsars with the Parkes radio telescope for 12 years, Shannon <jats:italic>et al.</jats:italic> found no detectable variation in pulsar records. This nondetection result indicates that a new detection strategy for gravitational waves is needed. </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="6255" page="1522" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab1910">1522</jats:related-article> </jats:p>

<jats:title>A clean and green approach to amines</jats:title> <jats:p> Enzymes evolved to operate in water and to modify their substrates using comparatively nontoxic reagents. Thus, a major advantage of applying enzymes to synthetic chemistry is their compatibility with environmentally benign conditions. Mutti <jats:italic>et al.</jats:italic> report that two enzymes—alcohol and amine dehydrogenases—can operate in tandem to convert alcohols to amines. The reaction proceeds with ammonium as the only input and water as the only byproduct. The mechanism relies on consecutive oxidation and reduction steps, with hydrogen shuttled by a nicotinamide coenzyme. </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="6255" page="1525" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac9283">1525</jats:related-article> </jats:p>

<jats:title>A solution for scalable-flow batteries</jats:title> <jats:p> Flow batteries, in which the redox active components are held in tanks separate from the active part of the cell, offer a scalable route for storing large quantities of energy. A challenge for their large-scale development is to avoid formulations that depend on toxic transition metal ions. Lin <jats:italic>et al.</jats:italic> show that quinones can be dissolved in alkaline solutions and coupled with ferricyanides to make a flow cell battery (see the Perspective by Perry). This gives scope for developing flow cells with very low costs, high efficiencies at practical power densities, simplicity of operation, and inherent safety. </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="6255" page="1529" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab3033">1529</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6255" page="1452" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aad0698">1452</jats:related-article> </jats:p>