Catálogo de publicaciones - revistas

<jats:title> Enhanced abundance of primordial HeH <jats:sup>+</jats:sup> </jats:title> <jats:p> Though only recently detected in space, the helium hydride ion (HeH <jats:sup>+</jats:sup> ) is thought to be the first molecule ever to have formed in the early Universe. Novotný <jats:italic>et al.</jats:italic> report state-specific rate coefficients for the dissociative reaction of HeH <jats:sup>+</jats:sup> with electrons, obtained using a cryogenic ion storage ring combined with a merged electron beam (see the Perspective by Bovino and Galli). They detect substantial rotational dependence and a decrease of the rates for the lowest states of HeH <jats:sup>+</jats:sup> , far below the values listed in astrochemistry databases and those previously applied in early-Universe models. These results suggest high abundance of this important primordial molecule at redshifts of first star and galaxy formation. </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="6454" page="676" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aax5921">676</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6454" page="639" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay5825">639</jats:related-article> </jats:p>

<jats:title>Strain-stabilized perovskites</jats:title> <jats:p> The perovskite materials used for solar cells and light-emitting diodes (which are black in color) are generally less stable at room temperature than the electronically inactive nonperovskite phases (which are yellow in color). Steele <jats:italic>et al.</jats:italic> show that for CsPbI <jats:sub>3</jats:sub> , strain induced in a thin film after annealing the material to 330°C and then rapidly cooling it to room temperature kinetically trapped the black phase. Grazing-incidence wide-angle x-ray scattering revealed the crystal distortions and texture formation created by interfacial strain. </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="6454" page="679" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aax3878">679</jats:related-article> </jats:p>

<jats:title>An unusual superconductor</jats:title> <jats:p> In conventional, and in many unconventional, superconductors, the electrons that form Cooper pairs have spins pointing in opposite directions. An applied magnetic field can easily “break” such pairs—and destroy superconductivity—by aligning both spins in the same direction. In contrast, spin-triplet superconductors are much more resilient to magnetic fields. Very few candidates for such materials have been discovered. Ran <jats:italic>et al.</jats:italic> add to this select group by observing signatures of spin-triplet superconductivity, including a very large and anisotropic upper critical magnetic field, in the material UTe <jats:sub>2</jats:sub> . Because spin-triplet superconductors may naturally exhibit topological superconductivity, this material may also be of interest in quantum computing. </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="6454" page="684" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aav8645">684</jats:related-article> </jats:p>

<jats:title>Strong perovskite interfaces</jats:title> <jats:p> The weak bonding in the crystal lattice of hybrid perovskites used in solar cells promotes surface decomposition and interferes with the formation of stable heterostructures with the charge carrier layers. Y. Wang <jats:italic>et al.</jats:italic> show that strong bonds are formed between lead and both chlorine and oxygen atoms in a film with a lead-rich surface and a chlorinated graphene oxide layer. This interface was used with common hole-transporting materials to fabricate solar cells that maintained 90% of their initial efficiency of 21% after operation at 60°C for 1000 hours. </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="6454" page="687" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aax8018">687</jats:related-article> </jats:p>

<jats:title>Diamond window into the deep mantle</jats:title> <jats:p> Helium isotopes provide a window into the very deepest and oldest parts of Earth's voluminous mantle. However, several processes tend to obscure the helium isotope signal from reservoirs in basaltic lavas that have erupted at the surface. Timmerman <jats:italic>et al.</jats:italic> identified a set of diamonds that formed deep within Earth and were rapidly erupted, which have avoided near-surface contamination. They find evidence for a deep, primordial rock source along with mixing of sediments from old subducting plates. The signatures extracted from these diamonds have implications for chemical and dynamic models of Earth. </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="6454" page="692" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aax5293">692</jats:related-article> </jats:p>

<jats:title>A newly discovered cell type for pain perception</jats:title> <jats:p> Pain has been thought to be initiated by activation of free nerve endings without end organs in the skin. In contrast to this paradigm, Abdo <jats:italic>et al.</jats:italic> discovered a previously unknown meshlike organ covering the skin that senses dangerous environmental stimuli (see the Perspective by Doan and Monk). This organ is built from specialized glial cells located in the epidermal-dermal border and is sufficient and required for initiation of mechanical pain transduction. </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="6454" page="695" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aax6452">695</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6454" page="641" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay6144">641</jats:related-article> </jats:p>

<jats:title>Visualizing neuronal activity in vivo</jats:title> <jats:p> Imaging the changes in fluorescence of voltage-sensitive reagents would enable monitoring of the activity of neurons in vivo. Abdelfattah <jats:italic>et al.</jats:italic> created such a voltage indicator by designing a protein that combines the voltage sensor domain from microbial rhodopsin with a domain that captures a dye molecule with exceptional brightness and photostability. When the protein was expressed in mice, flies, or zebrafish, they could monitor single action potentials in dozens of neurons simultaneously for many minutes. </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="6454" page="699" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aav6416">699</jats:related-article> </jats:p>

<jats:title>Active migration renews gut epithelia</jats:title> <jats:p> Epithelial tissues are continuously renewed throughout adult life, and the gut epithelium is the fastest self-renewing tissue in mammals. Over 3 days or so, epithelial cells migrate from the crypts, where they are born, to the tips of the villi, where they die. It is commonly believed that migration is strictly passive, driven by mitotic pressure in crypts—as cells divide, they push their neighbors upward. Krndija <jats:italic>et al.</jats:italic> now challenge this concept and show that cells migrate actively, using actin-rich basal protrusions oriented in the direction of migration (see the Perspective by Jansen). </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="6454" page="705" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aau3429">705</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6454" page="642" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay5861">642</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>