Catálogo de publicaciones - revistas

<jats:title>Sugar code regulates blood stem cells</jats:title> <jats:p> During embryonic development, blood stem cells are derived from vascular endothelial cells that line the walls of developing arteries. The transition from endothelial cells to blood stem cells is highly regulated and restricted to a small portion of endothelial cells during a brief period of time. The mechanisms regulating this transition are also poorly understood. Kasper <jats:italic>et al.</jats:italic> found that microRNA-223 intrinsically restrains the vascular hematopoietic transition by regulating N-glycan biosynthesis to restrict hematopoietic stem and progenitor cell production and differentiation. Genetics or chemicals could be used to alter the sugar code and change the efficiency of blood production in embryos. Thus, genetically or pharmacologically altering N-glycan biosynthesis in endothelial cells could improve the efficiency of the production of blood stem cells, which could then be used to treat blood diseases such as leukemia. </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="6521" page="1186" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aaz2121">1186</jats:related-article> </jats:p>

<jats:title>Restoring vision by stimulating the brain</jats:title> <jats:p> Electrical stimulation of the visual cortex has long been proposed as an approach to restoring vision in blind people. Previous studies positioned electrodes on the surface of the brain and thus required delivery of relatively high currents. However, this approach limits the number of electrodes that can be safely stimulated simultaneously, and such surface electrodes activate several millimeters of cortex, which results in a low spatial resolution. Chen <jats:italic>et al.</jats:italic> demonstrated that the simultaneous stimulation of multiple intracortical electrodes in the monkey primary visual cortex gives rise to the perception of shape and successive stimulation to the perception of motion (see the Perspective by Beauchamp and Yoshor). This major improvement provides proof of concept for the use of electrical microstimulation to create a form of artificial vision in the blind. </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="6521" page="1191" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd7435">1191</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6521" page="1165" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abf1925">1165</jats:related-article> </jats:p>

<jats:title>Competitive roots</jats:title> <jats:p> Much of the world's plant biomass exists out of sight underground in the form of roots. Cabal <jats:italic>et al.</jats:italic> developed a theoretical model and tested it empirically to explain the rules that govern root growth (see the Perspective by Semchenko). Plants adjust how and where their roots grow according to how close neighboring—and competing—plants might be. The model extracts some of the rules about how root balls differ when grown close to neighboring plants compared with being grown in the absence of competition. </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="6521" page="1197" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aba9877">1197</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6521" page="1167" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abf2785">1167</jats:related-article> </jats:p>

<jats:title>Probing the dark state</jats:title> <jats:p> Excitons, electron-hole pairs held together by Coulomb attraction, can be generated in semiconductors under excitation and greatly influence the material's optoelectronic properties. Although bright excitons are optically active, their dark-state cousins have been more difficult to detect. They do, however, affect the optoelectronic properties through their interaction with light and bright excitons. Madéo <jats:italic>et al.</jats:italic> developed a pump-probe photoemission technique that is used reveal the spatial, temporal, and spectral dynamics of excitons (see the Perspective by Na and Ye). Demonstrated in two-dimensional monolayer films of tungsten diselenide, the technique could also be applicable to other semiconductor systems hosting excitonic excitations. </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="6521" page="1199" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aba1029">1199</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6521" page="1166" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abf0371">1166</jats:related-article> </jats:p>

<jats:title>Probing quantum materials</jats:title> <jats:p> Unraveling the functionalities of quantum materials such as spin-valley-electronic, topological, and many-body effects provides a route to exploiting these materials for applications. Borsch <jats:italic>et al.</jats:italic> introduce a spectroscopic technique based on the concept of crystal-momentum combs. By extending the ideas of frequency combs of metrology and superresolution imaging, they demonstrate the ability to directly map out the properties of quantum electronic structures under ambient conditions. Using this technique combined with accurate many-body computations, they were able to reveal tomographic images of two-dimensional quantum materials. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6521" page="1204" related-article-type="in-this-issue" vol="370">1204</jats:related-article> </jats:p>

<jats:title>A decoy to neutralize SARS-CoV-2</jats:title> <jats:p> Many efforts to develop therapies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are focused on the interaction between the spike protein, which decorates the surface of the virus, and its host receptor, human angiotensin-converting enzyme 2 (hACE2). Linsky <jats:italic>et al.</jats:italic> describe a de novo design strategy that allowed them to engineer decoy proteins that bind to the spike protein by replicating the hACE2 interface. The best decoy, CTC-445, bound with low nanomolar affinity, and selection of viral mutants that decrease binding is unlikely because this would also affect binding to hACE2. A bivalent version of CTC-445 bound even more tightly, neutralized SARS-CoV-2 infection of cells, and protected hamsters from a SARS-CoV-2 challenge. The stable decoy has the potential for respiratory therapeutic delivery. </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="6521" page="1208" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abe0075">1208</jats:related-article> </jats:p>

<jats:title>Protection in the wings</jats:title> <jats:p>Beetles have hardened forewings for the protection of their bodies and hindwings, and their use during crawling or burrowing is well understood. However, the behavior of the larger hindwings during collisions in flight has not been clear because they do not readily flex. Phan and Park present a detailed study of the folding and unfolding mechanisms of the hindwings in free-flying rhinoceros beetles in which the wings were impacted during flight to simulate a cluttered environment (see the Perspective by Sun). They found that origami-like folds in the wing could rapidly collapse on impact and then spring back, thus acting as shock absorbers and stabilizers. The authors replicated this behavior in a flapping-wing robot, enabling it to fly safely after collisions.</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="6521" page="1214" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd3285">1214</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6521" page="1165" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abf1925">1165</jats:related-article> </jats:p>