Catálogo de publicaciones - revistas

<jats:title>Transient radio jet from a black hole</jats:title> <jats:p> When a star passes too close to a supermassive black hole, it gets ripped apart by the gravitational forces. This causes a tidal disruption flare as the material falls into the black hole. van Velzen <jats:italic>et al.</jats:italic> monitored one such flare with radio telescopes and found evidence for a transient relativistic jet launched by the black hole (see the Perspective by Bower). Larger jets are a feature of active galactic nuclei and have a profound effect on their host galaxy, but are poorly understood. The results will aid our understanding of how black holes “feed” and of the processes governing jet formation. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/351/6268/62.full">62</jats:ext-link> ; see also p. <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/351/6268/30.full">30</jats:ext-link> </jats:p>

<jats:title>Water isomers hide their origin</jats:title> <jats:p> H <jats:sub>2</jats:sub> O exists in two spin isomers, ortho and para, in a ratio of 3:1 at room temperature. Some astronomical observations have found water with a ratio of less than 3, thought to be due to water being photodesorbed from ice that had been formed at very low temperatures (≾30 K). Hama <jats:italic>et al.</jats:italic> tested this idea in the laboratory, by forming water ice at low temperature and then photodesorbing it to measure the ortho:para ratio. They found a ratio of 3, even at 10 K. Thus, another explanation for the low ratios in some astronomical objects must be found. </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="6268" page="65" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad4026">65</jats:related-article> </jats:p>

<jats:title> Separating H <jats:sup>+</jats:sup> from D <jats:sup>+</jats:sup> </jats:title> <jats:p> In many respects, hydrogen and deuterium show similar properties because they share the same number of protons and electrons and only differ by one neutron. However, when you strip away the electron, a proton ends up having less than half the radius of a deuterion. Lozada-Hidalgo <jats:italic>et al.</jats:italic> used two-dimensional membranes of graphene or hexagonal boron nitride to separate these two charged isotopes, with a separation factor of about 10. </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="6268" page="68" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aac9726">68</jats:related-article> </jats:p>

<jats:title>A two-for-one twist on Suzuki coupling</jats:title> <jats:p> The Suzuki-Miyaura coupling reaction is one of the most widely used ways of making carbon-carbon bonds. Essentially a palladium catalyst activates one carbon fragment and then links it to a second fragment pulled from boron. Zhang <jats:italic>et al.</jats:italic> now demonstrate a twist on the conventional pathway (see the Perspective by Fyfe and Watson). In their system, the palladium initially coaxes together two carbon fragments on one boron center. Then the catalyst stitches a second C-C bond to a third, external fragment. A chiral ligand renders the reaction highly enantio-selective. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/351/6268/70.full">70</jats:ext-link> ; see also p. <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/351/6268/26.full">26</jats:ext-link> </jats:p>

<jats:title>Using light in the darkness</jats:title> <jats:p> Solid-state devices can efficiently capture solar energy to produce chemicals and fuels from carbon dioxide. Yet biology has already developed a high-specificity, low-cost system to do just that through photosynthesis. Sakimoto <jats:italic>et al.</jats:italic> developed a biological-inorganic hybrid that combines the best of both worlds (see the Perspective by Müller). They precipitated semiconductor nanoparticles on the surface of a nonphotosynthetic bacterium to serve as a light harvester. The captured energy sustained cellular metabolism, producing acetic acid: a natural waste product of respiration. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/351/6268/74.full">74</jats:ext-link> ; see also p. <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/351/6268/34.full">34</jats:ext-link> </jats:p>

<jats:title>Coronaviruses in the Middle East</jats:title> <jats:p> Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe acute respiratory illness and kills about a third of people infected. The virus is common in dromedary camels, which can be a source of human infections. In a survey for MERSCoV in over 1300 Saudi Arabian camels, Sabir <jats:italic>et al.</jats:italic> found that dromedaries share three coronavirus species with humans. Diverse MERS lineages in camels have caused human infections, which suggests that transfer among host species occurs quite easily. Haagmans <jats:italic>et al.</jats:italic> made a MERS-CoV vaccine for use in camels, using poxvirus as a vehicle. The vaccine significantly reduced virus excretion, which should help reduce the potential for transmission to humans, and conferred cross-immunity to camelpox infections. </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="6268" page="81" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aac8608">81</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6268" page="77" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad1283">77</jats:related-article> </jats:p>

<jats:title>Coronaviruses in the Middle East</jats:title> <jats:p> Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe acute respiratory illness and kills about a third of people infected. The virus is common in dromedary camels, which can be a source of human infections. In a survey for MERSCoV in over 1300 Saudi Arabian camels, Sabir <jats:italic>et al.</jats:italic> found that dromedaries share three coronavirus species with humans. Diverse MERS lineages in camels have caused human infections, which suggests that transfer among host species occurs quite easily. Haagmans <jats:italic>et al.</jats:italic> made a MERS-CoV vaccine for use in camels, using poxvirus as a vehicle. The vaccine significantly reduced virus excretion, which should help reduce the potential for transmission to humans, and conferred cross-immunity to camelpox infections. </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="6268" page="81" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aac8608">81</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6268" page="77" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad1283">77</jats:related-article> </jats:p>

<jats:title>Making the correct cut</jats:title> <jats:p> The CRISPR/Cas system is a prokaryotic immune system that targets and cuts out foreign DNA in bacteria. It has been adopted for gene editing because it can be designed to recognize and cut specific locations in the genome. A challenge in developing clinical applications is the potential for off-target effects that could result in DNA cleavage at the wrong locations. Slaymaker <jats:italic>et al.</jats:italic> used structure-guided engineering to improve the specificity of <jats:italic>Streptococcus pyogenes</jats:italic> Cas9 (SpCas9). They identified enhanced-specificity variants (eSpCas9) that display reduced off-target cleavage while maintaining robust on-target activity </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="6268" page="84" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad5227">84</jats:related-article> </jats:p>

<jats:title>Seeing the signal sequence in action</jats:title> <jats:p>Protein translocation across the endoplasmic reticulum (ER) involves the interaction of a signal sequence with the protein translocation channel. Although much work has looked at the details of protein translocation, questions remain. Voorhees and Hegde present a single-particle cryoelectron microscopy study of the mammalian ER translocation apparatus at the point in which the signal sequence is engaging the translocation pore.</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="6268" page="88" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad4992">88</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>