Catálogo de publicaciones - revistas

<jats:title>Optomechanical upconversion</jats:title> <jats:p> Molecules have rich signatures in their spectra at infrared wavelengths and are typically accessed with dedicated spectroscopic instrumentation. Chen <jats:italic>et al</jats:italic> . and Xomalis <jats:italic>et al</jats:italic> . report optomechanical frequency upconversion from the mid-infrared to the visible domain using molecular vibrations coupled to a plasmonic nanocavity at ambient conditions (see the Perspective by Gordon). Using different nanoantenna designs, one with a nanoparticle-on-resonator and the other with nanoparticle-in-groove, both approaches show the ability to upconvert the mid-infrared vibrations of the molecules in the nanocavity to visible light wavelengths. The effect could be used to simplify infrared spectroscopy, possibly with single-molecule sensitivity. —ISO </jats:p>

<jats:title>A nearby iron-rich sub-Earth planet</jats:title> <jats:p> The mass and radius of an exoplanet determine its mean density, which provides information about the possible interior structure. Lam <jats:italic>et al</jats:italic> . have identified a planet on a 7.7-hour orbit around a nearby red dwarf star. The authors determined the planet’s radius from the transit, then used radial velocity observations to measure the mass. They found a sub-Earth–sized planet with a density almost equivalent to pure iron. Its high surface temperature is close to the vaporization point of iron, suggesting that it is the iron core of a planet that has lost its outer mantle. —KTS </jats:p>

<jats:title>Up in the air</jats:title> <jats:p> Understanding ocean-atmospheric carbon dioxide (CO <jats:sub>2</jats:sub> ) fluxes in the Southern Ocean is necessary for quantifying the global CO <jats:sub>2</jats:sub> budget, but measurements in the harsh conditions there make collecting good data difficult, so a quantitative picture still is out of reach. Long <jats:italic>et al</jats:italic> . present measurements of atmospheric CO <jats:sub>2</jats:sub> concentrations made by aircraft and show that the annual net flux of carbon into the ocean south of 45°S is large, with stronger summertime uptake and less wintertime outgassing than other recent observations have indicated. —HJS </jats:p>

<jats:title>Desaturating acids</jats:title> <jats:p> Molecular motifs with neighboring C=C and C=O double bonds are central to the synthesis of fine chemicals, pharmaceuticals, and polymers. Wang <jats:italic>et al</jats:italic> . report a versatile palladium-catalyzed reaction to produce this motif from carboxylic acids by oxidation of the adjacent carbons, with molecular oxygen as a viable terminal oxidant (see the Perspective by Iwabuchi). The method relies on fine-tuned ligand geometry and complements approaches constrained by their reliance on enolate chemistry. Swapping in an alternate ligand promotes extension of the desaturation to coupling with terminal alkynes. —JSY </jats:p>

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<jats:p>Sibert and Rubin (Reports, 4 June 2021, p. 1105) claim to have identified a previously unidentified, major extinction event of open-ocean sharks in the early Miocene. We argue that their interpretations are based on an experimental design that does not account for a considerable rise in the sedimentation rate coinciding with the proposed event, nor for intraspecific variation in denticle morphology.</jats:p>

<jats:title>Mechanosensitive nuclear pores</jats:title> <jats:p> The nucleus of eukaryotic cells is enclosed by the nuclear envelope, a double membrane punctuated with nuclear pore complexes (NPCs). These giant channels in the nuclear envelope mediate nucleocytoplasmic exchange. Zimmerli <jats:italic>et al</jats:italic> . show that the mechanical status of the nuclear membranes controls their nuclear pore diameter. Pulling forces imposed through nuclear membranes lead to stretching of NPCs and dilation of their diameter, whereas relief of such forces causes NPC constriction. Thus, the control of nuclear size and shape is functionally linked with NPC conformation and nucleocytoplasmic transport activity. —SMH </jats:p>

<jats:p> Feichtinger <jats:italic>et al</jats:italic> . assert that the reduction in denticle abundance and diversity we found are incorrect, claiming that we failed to consider changes in sedimentation rate. However, we used standard methods that explicitly account for changes in sedimentation rate and density. We maintain that our initial dataset and conclusions are robust and provide evidence for a major early Miocene extinction in pelagic sharks. </jats:p>