Catálogo de publicaciones - revistas

<jats:title>Making mitochondrial hydrophobic proteins</jats:title> <jats:p> Mitochondria produce chemical energy for the cell. Human mitochondria have their own specific ribosomes—mitoribosomes, which are distinct from cytoplasmic ribosomes. Mitoribosomes synthesize the mitochondrial membrane proteins that generate the chemical energy. Brown <jats:italic>et al.</jats:italic> used cryo–electron microscopy to determine the high-resolution structure of the large subunit of the human mitoribosome. The mitoribosome has a number of unique features, including an exit tunnel lined with hydrophobic amino acid residues. </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="6210" page="718" related-article-type="in-this-issue" vol="346" xlink:href="10.1126/science.1258026">718</jats:related-article> </jats:p>

<jats:title>Nailing down a quantum spin liquid</jats:title> <jats:p> Quantum spin liquids (QSLs) possess magnetic interactions that, even at absolute zero temperature, remain in a disordered liquid-like spin state. It is very difficult to prove unambiguously that a material is a QSL, because there is always a possibility that it can become ordered below the lowest measured temperature. Barkeshli <jats:italic>et al.</jats:italic> used quantum field theory to propose a direct way to identify a QSL by placing it in contact with other exotic materials, such as superconductors or magnets. The theory predicted that, at such a boundary, electrons entering the QSL would turn into excitations lacking charge or lacking spin. Future experiments may be able to detect this transmutation. </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="6210" page="722" related-article-type="in-this-issue" vol="346" xlink:href="10.1126/science.1253251">722</jats:related-article> </jats:p>

<jats:title>Doubling up on optically driven catalysis</jats:title> <jats:p> During photosynthesis, plants absorb light from the Sun four consecutive times before they accumulate enough energy to make oxygen from water. In contrast, when chemists harness light energy to promote reactivity, they tend to rely on single discrete absorption events. Ghosh <jats:italic>et al.</jats:italic> now show that a particular dye molecule can channel the combined energy from two absorbed photons to the reduction and subsequent coupling reactions of aryl halide molecules. The method expands the reach of photocatalysis to a broader range of compounds, such as chlorides, which are too stable to breach with a single photon. </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="6210" page="725" related-article-type="in-this-issue" vol="346" xlink:href="10.1126/science.1258232">725</jats:related-article> </jats:p>

<jats:title>Melting can follow many pathways</jats:title> <jats:p> Melting involves the loss of order as additional kinetic energy is added to a system. Although simple models of this sort of phase transition exist, it can be very difficult to observe the initial stages either experimentally or using simulations. Samanta <jats:italic>et al.</jats:italic> developed a robust rareevent sampling technique that makes it possible to examine melting events without needing excessive computing time (see the Perspective by van de Walle). For both copper and aluminum, they observed the formation of defects that act as starting points for the melting process rather than the homogeneous loss of order assumed in classic nucleation theory. </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="6210" page="729" related-article-type="in-this-issue" vol="346" xlink:href="10.1126/science.1253810">729</jats:related-article> </jats:p>