Catálogo de publicaciones - revistas

<jats:title>Complex chiral particles</jats:title> <jats:p> Synthetic colloids are usually smooth, but nature can produce micrometer-scale particles with intricate structure and shape, such as the coccoliths produced by algae. Jiang <jats:italic>et al.</jats:italic> controlled the self-assembly of gold–cysteine nanoplatelets into a variety of chiral, hierarchically organized colloidal particles by changing the chiral fraction of cysteine and the nucleation temperature. Organic cations created electrostatic repulsions that favored edge assembly of the nanoplatelets, which in turn could create surfaces bearing twisted spikes. </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="6491" page="642" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz7949">642</jats:related-article> </jats:p>

<jats:title>Hybrid approach catches light</jats:title> <jats:p> Plant chloroplasts enclose two major photosynthetic processes: light reactions, which generate the energy carriers adenosine triphosphate and reduced nicotinamide dinucleotide phosphate (NADPH), and dark reactions, which use these molecules to fix carbon dioxide and build biomass. Miller <jats:italic>et al.</jats:italic> appropriated natural components, thylakoid membranes from spinach, for the light reactions and showed that these could be coupled to a synthetic enzymatic cycle that fixes carbon dioxide within water-in-oil droplets. The composition of the droplets could be tuned and optimized and the metabolic activity monitored in real time by NADPH fluorescence (see the Perspective by Gaut and Adamala). These chloroplast-mimicking droplets bring together natural and synthetic components in a small space and are amenable to further functionalization to perform complex biosynthetic tasks. </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="6491" page="649" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz6802">649</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6491" page="587" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abc1226">587</jats:related-article> </jats:p>

<jats:title>Collecting a sample of asteroid Ryugu</jats:title> <jats:p> The Hayabusa2 spacecraft recently traveled to the nearby carbonaceous asteroid Ryugu to collect samples and return them to Earth for laboratory analysis. Morota <jats:italic>et al.</jats:italic> describe Hayabusa2's first sample collection, taken during a brief touchdown on Ryugu's surface. Close-up images and video taken during the sampling process allowed the authors to investigate the surface colors and morphology on a small scale. Relating these to the surface craters and stratigraphy constrains the evolution of Ryugu. The authors conclude that the asteroid experienced a prior period of strong solar heating caused by changes in its orbit. The sample is expected to arrive on Earth in December 2020. </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="6491" page="654" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz6306">654</jats:related-article> </jats:p>

<jats:title>Circumventing spatter</jats:title> <jats:p> Laser powder bed fusion is an additive manufacturing technique that laser-melts powder layer by layer to build a three-dimensional (3D) part. Khairallah <jats:italic>et al.</jats:italic> used experiments and a multiphysics model to determine the origin of the melt spatter and defect formation that degrade the properties of built parts (see the Perspective by Polonsky and Pollock). Informed modulation of laser power is important to avoid disturbing the powder bed and creating laser shadowing. This reduces pore formations and leads to more uniform properties of 3D-printed parts. </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="6491" page="660" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aay7830">660</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6491" page="583" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb4938">583</jats:related-article> </jats:p>

<jats:title>Atypical vibrational interactions</jats:title> <jats:p> Vibrational energy transfer (VET) between solute molecules is generally unfavorable in liquids because of weak intermolecular forces. Xiang <jats:italic>et al.</jats:italic> measured the two-dimensional infrared spectrum of a molecular mixture, W(CO) <jats:sub>6</jats:sub> and W( <jats:sup>13</jats:sup> CO) <jats:sub>6</jats:sub> , with saturated concentrations in a binary solvent embedded in an optical microcavity. This experiment showed that the VET between the asymmetric stretch vibrations of two solute molecules is enhanced via polaritonic intermediate states formed by a strong coupling with the cavity mode. The efficiency is modulated by the cavity lifetime, which provides an opportunity to control the VET process in the liquid phase. This could lead to various practical implementations. </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="6491" page="665" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aba3544">665</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>