Catálogo de publicaciones - revistas

<jats:title>Mastering regulation</jats:title> <jats:p> The mechanistic target of rapamycin complex 1 (mTORC1) is known as the master kinase, acknowledging its key role in integrating multiple signals to regulate cell growth. When nutrients are abundant, heterodimers of Rag, a class of small guanosine triphosphatase, bind to mTORC1 and recruit it to the lysosome. Here, other signaling pathways converge on the mTORC1 complex. Anandapadamanaban <jats:italic>et al.</jats:italic> determined cryo–electron microscopy and crystal structures of a RagA/RagC heterodimer. The structures, together with dynamic studies, explain the nucleotide states required for binding to mTORC1 and support a mechanism for conformational communication between the RagA and RagC subunits in the heterodimer. RagA/RagC binding causes no conformational change in mTORC1, which is consistent with the idea that mTORC1 must sense additional growth regulators before it is activated. </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="6462" page="203" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax3939">203</jats:related-article> </jats:p>

<jats:title>Getting more bits out of PCRAM</jats:title> <jats:p> Phase-change random access memory (PCRAM) has the ability to both store and process information. It also suffers from noise and electrical drift due to damage that accumulates during the cycling process. Ding <jats:italic>et al.</jats:italic> developed a phase-change heterostructure where a phase-change material is separated by a confinement material, creating an alternating stack (see the Perspective by Gholipour). This architecture results in ultralow noise, lower drift, and stable multilevel storage capacity, which are potentially useful for new forms of 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="6462" page="210" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aay0291">210</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6462" page="186" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaz1129">186</jats:related-article> </jats:p>

<jats:title>Twisting is cool</jats:title> <jats:p> Rubber bands that are stretched and held in an extended shape for a while will extract heat from their surroundings as they are allowed to relax, owing to a reversal of stress-induced crystallization, which is an exothermic process. Wang <jats:italic>et al.</jats:italic> examine the potential for solid-state cooling of twisted fibers, along with configurations such as supercoiling, for materials including natural rubber, polyethylene, and nickel-titanium fibers. The cooling is related to the change in entropy of the material as it is mechanically deformed. </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="6462" page="216" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax6182">216</jats:related-article> </jats:p>

<jats:title>Modulating superconductivity</jats:title> <jats:p> Strain can have considerable effects on the electronic properties of materials. For instance, the temperature at which a material becomes superconducting—the critical temperature—can be tuned by varying strain. Bachmann <jats:italic>et al.</jats:italic> used focused ion beam milling to fabricate microstructures of the superconductor CeIrIn <jats:sub>5</jats:sub> on sapphire substrate. A difference in the thermal contraction coefficients of the two layers induced nonuniform strain upon cooling of the sample, leading to large gradients of the critical temperature. This approach can be used in other materials and may enable fabrication of superconducting circuitry without physical junctions. </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="6462" page="221" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aao6640">221</jats:related-article> </jats:p>