Catálogo de publicaciones - revistas

<jats:title>Epitaxial films through spin coating</jats:title> <jats:p> A simple way to coat a surface with a uniform film is by spin coating. The substrate is spun at high speed, and a droplet of solution containing the coating is added at the center, spreads out, and evaporates. This method is used to make polycrystalline inorganic coatings and amorphous films, such as polymers used in lithography. Kelso <jats:italic>et al.</jats:italic> performed spin coating with single-crystal substrates, carefully controlling the thickness of the spreading solution on the basis of its viscosity and the rotation rate. In this way, they achieved epitaxial growth—in which the crystallites are oriented by the substrate—for perovskites, zinc oxide, and sodium chloride. </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="6436" page="166" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw6184">166</jats:related-article> </jats:p>

<jats:title>Making heat stand still</jats:title> <jats:p> Dissipative oscillating systems (waves) can be described mathematically in terms of non-Hermitian physics. When parity-time symmetric systems have dissipative components, the interplay between gain and loss can lead to unusual and exotic behavior. Li <jats:italic>et al.</jats:italic> show theoretically and demonstrate experimentally that such behavior need not be limited to wave systems. Looking at the diffusion of heat, they devised an experimental setup comprising two thermally coupled disks rotating in opposite directions. The thermal energy transported by each disk is strongly coupled to the disk rotating in the opposite direction, providing a return path for the heat wave. For a particular rotation rate, there is an exceptional point where thermal coupling and counterrotating motion balance, resulting in the thermal energy profile being stationary over time. </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="6436" page="170" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw6259">170</jats:related-article> </jats:p>

<jats:title>Ecosystems feel war's effects</jats:title> <jats:p> War ravages human lives and landscapes, but nonhuman victims are no less affected. The Mozambican Civil War resulted in the rapid decline of predators in Gorongosa National Park and led to a trophic cascade that shifted prey behaviors and plant communities. Atkins <jats:italic>et al.</jats:italic> monitored this shift and found that the absence of wild dogs and leopards resulted in a change in habitat use and plant consumption by bushbuck, which are forest-dwelling antelopes. Experiments further showed that changes in prey behavior were reversible when signs of predator activity were introduced, supporting the impact of the predator loss. These results confirm patterns seen elsewhere and go further in providing mechanistic detail about the importance of the “landscape of fear” perceived by prey animals. </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="6436" page="173" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aau3561">173</jats:related-article> </jats:p>

<jats:title>A fatty acid triggers immune responses</jats:title> <jats:p> Plants and animals respond to the microbial communities around them, whether in antagonistic or mutualistic ways. Some of these interactions are mediated by lipopolysaccharide—a large, complex, and irregular molecule on the surface of most Gram-negative bacteria. Studying the small mustard plant <jats:italic>Arabidopsis</jats:italic> , Kutschera <jats:italic>et al.</jats:italic> identified a 3-hydroxydecanoyl chain as the structural element sensed by the plant's lectin receptor kinase. Indeed, synthetic 3-hydroxydecanoic acid alone was sufficient to produce a response. A small microbial metabolite may thus suffice to trigger immune responses. </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="6436" page="178" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aau1279">178</jats:related-article> </jats:p>

<jats:title>Controlling cooling</jats:title> <jats:p> On million-year time scales, Earth's climate state is determined by sources and sinks of carbon to the ocean-atmosphere system. But which specific mechanisms are important in controlling the timing of glacial intervals? Macdonald <jats:italic>et al.</jats:italic> identify arc-continent collisions in the tropics as a primary control (see the Perspective by Hartmann). They compiled a database of Phanerozoic arc-continent collisions and the latitudinal distribution of ice sheets, showing that ice coverage was greatest when those collisions were most widespread, maximizing global weatherability. </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="6436" page="181" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav5300">181</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6436" page="126" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax1657">126</jats:related-article> </jats:p>

<jats:title>The price of staying warm</jats:title> <jats:p> Among vertebrates, zebrafish and salamanders can regenerate their hearts, whereas adult mice and humans cannot. Hirose <jats:italic>et al.</jats:italic> analyzed diploid cardiomyocyte frequency as a proxy for cardiac regenerative potential across 41 vertebrate species (see the Perspective by Marchianò and Murry). They observed an inverse correlation of these cells with thyroid hormone concentrations during the ectotherm-to-endotherm transition. Mice with defects in thyroid hormone signaling retained significant heart regenerative capacity, whereas zebrafish exposed to excessive thyroid hormones exhibit impaired cardiac repair. Loss of heart regenerative ability in mammals may represent a trade-off for increases in metabolism necessary for the development of endothermy. </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="6436" page="184" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aar2038">184</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6436" page="123" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax1006">123</jats:related-article> </jats:p>

<jats:title>Deubiquitinase fine-tunes Notch signaling</jats:title> <jats:p> The branching of blood vessels is controlled in part by signaling through Notch receptor proteins. When NOTCH1 binds its ligand DLL4, the intracellular domain (NICD1) is cleaved from the receptor and works with other proteins to regulate gene transcription. In a screen for proteins that interacted with NICD1 in human cells in culture, Lim <jats:italic>et al.</jats:italic> identified the deubiquitinase USP10. NICD1 is rapidly ubiquitinated and degraded in cells, but interaction of NICD1 with USP10 counteracts ubiquitination of NICD1 and stimulates Notch signaling. Genetic experiments in mice support a role for USP10 in fine-tuning Notch signaling during vascular morphogenesis. </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="6436" page="188" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aat0778">188</jats:related-article> </jats:p>

<jats:title>Adaptation by way of compromise</jats:title> <jats:p> Many plants rely on animal pollinators to spread pollen and increase the genetic diversity of their offspring. However, there are trade-offs, because attracting pollinators may also attract herbivores and deterring predation may diminish floral displays. Ramos and Schiestl studied the interplay between mating system, flowers, and chemical defenses over several generations in <jats:italic>Brassica rapa</jats:italic> plants (see the Perspective by Ågren). Evolution driven by pollination and herbivory can be observed after only eight generations, suggesting that trade-offs have large evolutionary consequences. </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="6436" page="193" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav6962">193</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6436" page="122" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax1656">122</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>