Catálogo de publicaciones - revistas

<jats:title>The making of a lumen</jats:title> <jats:p> During the early days of mammalian development, the formation and positioning of a fluid-filled lumen, the blastocoel, defines the first axis of embryo symmetry. Dumortier <jats:italic>et al.</jats:italic> describe how a blastocoel lumen arises from the hydraulic fracturing of cell-cell contacts into hundreds of micrometer-size water pockets that then form a single large lumen (see the Perspective by Arroyo and Trepat). The authors characterized the process of lumen formation mechanically and molecularly and were able to manipulate the first axis of symmetry of the mammalian embryo experimentally. Thus, fluid dynamics plays a key role in the embryo and may play a similar role in the formation of other biological cavities. </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="6452" page="465" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aaw7709">465</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6452" page="442" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay2860">442</jats:related-article> </jats:p>

<jats:title>Not as hot as we thought</jats:title> <jats:p> Earth's early oceans appear not to have been as hot as some have suggested. The oxygen isotope composition of marine carbonates has changed markedly over the past 3.5 billion years. However, it has been difficult to determine whether that is because of a cooling of the seawater (from temperatures as high as 70°C) or an actual change in the isotope composition of the water. Galili <jats:italic>et al.</jats:italic> calibrated the temperature-dependent oxygen isotope fractionation between iron oxides and aqueous solutions and constructed an oxygen isotope record in marine iron oxides covering the past 2 billion years. Their findings suggest that a change in the isotope composition of the water, rather than its cooling, underlies the observed geological trend. </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="6452" page="469" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aaw9247">469</jats:related-article> </jats:p>

<jats:title>Stability through oxysalts</jats:title> <jats:p> The stability of organic-inorganic perovskite solar cells is limited by degradation from oxygen and water. Yang <jats:italic>et al.</jats:italic> show that in situ reaction of perovskites with sulfate or phosphate ions can create thin, strongly bonded lead oxysalt layers that protect defect sites. This layer also boosts charge carrier lifetimes that lead to a power conversion efficiency of more than 20%. Encapsulated devices maintained about 97% of this efficiency with simulated solar irradiation for nearly 2 months at a realistic operation temperature of 65°C. </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="6452" page="473" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aax3294">473</jats:related-article> </jats:p>

<jats:title>Cepheids help to map the Galaxy</jats:title> <jats:p> Cepheid variable stars pulsate, which allows their distances to be determined from the periodic variations in brightness. Skowron <jats:italic>et al.</jats:italic> constructed a catalog of thousands of Cepheids covering a large fraction of the Milky Way. They combined optical and infrared data to determine the stars' pulsation periods and mapped the distribution of Cepheids and the associated young stellar populations across the Galaxy. Their three-dimensional map demonstrates the warping of the Milky Way's disc. A simple model of star formation in the spiral arms reproduced the positions and ages of the Cepheid population. </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="6452" page="478" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aau3181">478</jats:related-article> </jats:p>

<jats:title>If I only had a heart</jats:title> <jats:p> 3D bioprinting is still a fairly new technique that has been limited in terms of resolution and by the materials that can be printed. Lee <jats:italic>et al.</jats:italic> describe a 3D printing technique to build complex collagen scaffolds for engineering biological tissues (see the Perspective by Dasgupta and Black). Collagen gelation was controlled by modulation of pH and could provide up to 10-micrometer resolution on printing. Cells could be embedded in the collagen or pores could be introduced into the scaffold via embedding of gelatin spheres. The authors demonstrated successful 3D printing of five components of the human heart spanning capillary to full-organ scale, which they validated for tissue and organ function. </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="6452" page="482" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aav9051">482</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6452" page="446" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay0478">446</jats:related-article> </jats:p>

<jats:title>Parallel and idiosyncratic fish adaptation</jats:title> <jats:p> Fish populations respond rapidly to fishing pressure. Within a handful of generations, marked phenotypic change can occur—often to smaller body sizes, because it is the big fish that are usually extracted. Therkildsen <jats:italic>et al.</jats:italic> examined wild ancestor fish lineages and found that polygenic mechanisms underpin this rapid evolutionary capacity (see the Perspective by Jørgensen and Enberg). Phenotypic change happened in two ways: first, by multiple small parallel changes in hundreds of unlinked genes associated with growth variation in the wild, and second, by shifts in large blocks of linked genes, causing large allele frequency changes at some loci. </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="6452" page="487" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aaw7271">487</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6452" page="443" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay3158">443</jats:related-article> </jats:p>

<jats:title>A sound way to deliver power</jats:title> <jats:p> Implanted medical devices, such as pacemakers and neurological stimulators, require a source of power, usually in the form of a battery. If a battery is implanted with the device, replacing it would require additional surgery. On the other hand, external power packs are prone to lead to infections where their wires enter the body. Hinchet <jats:italic>et al.</jats:italic> describe a triboelectric generator that can convert externally applied ultrasound into an internal electricity source capable of delivering sufficient energy to recharge a battery on a daily basis. </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="6452" page="491" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aan3997">491</jats:related-article> </jats:p>