Editors' Choice

Science  22 Jun 2018:
Vol. 360, Issue 6395, pp. 1311
  1. Planetary Science

    Benzene ice clouds in Titan's atmosphere

    1. Keith T. Smith

    Night-side view of Saturn's moon Titan, showing its hazy atmosphere

    PHOTO: NASA/JPL-CALTECH/SPACE SCIENCE INSTITUTE

    Titan, the largest moon of Saturn, has a thick atmosphere composed mostly of nitrogen, with smaller amounts of organic molecules such as methane and benzene. Vinatier et al. have analyzed infrared spectra of Titan obtained by the Cassini spacecraft during flybys of the moon. In addition to the expected gas-phase species, colder regions show a spectral signature consistent with solid benzene. After eliminating alternative explanations, the authors conclude that stratospheric clouds of benzene ice are present, particularly over Titan's south pole. The clouds are analogous to high-altitude cirrus clouds on Earth, which are composed of solid water-ice crystals.

    Icarus 310, 89 (2018).

  2. Organic Chemistry

    Making a triple negative

    1. Jake Yeston

    The trifluoromethanesulfonyl (Tf) group is remarkably adept at stabilizing negative charge: It boasts highly withdrawing fluorines and sulfur-oxygen bonds that can delocalize electrons through resonance. Höfler et al. took full advantage of these properties in generating a molecule with three independent anionic carbon centers. The synthetic reaction coupled triformylmethane with three equivalents of Tf2CH2, after which a base deprotonated all three Tf-substituted carbon centers. The compound was characterized by crystallography and showed trigonal-planar geometries at each charged carbon.

    Angew. Chem. Int. Ed. 10.1002/anie.201803647 (2018).

  3. Planktonic Neuroscience

    Paired photoreceptors function as an oceanic depth gauge

    1. Pamela J. Hines

    Two different photoreceptors allow an annelid to choose its depth.

    PHOTO: MARTIN GÜHMANN (CC BY-SA 4.0)

    Ciliary photoreceptors, which are typical of vertebrates, differ in morphology and in type of opsins from the rhabdomeric photoreceptors characteristic of annelids. Larvae of the marine annelid Platynereis dumerilii have both kinds of photoreceptors. Verasztó et al. worked out the circuits and responses driven by this pairing. The ciliary photoreceptors respond to ultraviolet (UV) light, causing the larvae to swim away from it. The rhabdomeric photoreceptors respond to blue light and drive a phototactic response. At the ocean surface, the UV-avoidance response dominates, driving larvae downward, whereas at greater depths, the phototactic response dominates, driving larvae toward the surface. When the swim-upward signal balances out the swim-downward signal, the larvae have found their favorite depth.

    eLife 10.7554/eLife.36440 (2018).

  4. Oncology

    A ray of hope for advanced breast cancer

    1. Paula A. Kiberstis

    Immunotherapies are revolutionizing cancer treatment. Yet certain common cancer types, such as breast cancer, are often missing from the immunotherapy conversation. One reason is that breast cancers express relatively few neoantigens, or mutant tumor-associated proteins that are targeted by the immune system. A case study now shows that in the setting of adoptive T cell therapy, this problem can be circumvented, resulting in a dramatic clinical response. Zacharakis et al. report that a patient with metastatic breast cancer showed complete durable remission of her disease after being treated with autologous tumor-infiltrating lymphocytes that had been enriched ex vivo for reactivity to just four neoantigens. This study lays the groundwork for studies of other cancers assumed to be refractory to immunotherapy.

    Nat. Med. 10.1038/s41591-018-0040-8 (2018).

  5. Sleep

    A good excuse to sleep in

    1. Priscilla N. Kelly

    Sleeping in on the weekend may make up for less sleep during the week.

    PHOTO: MLADEN MITRINOVIC/SHUTTERSTOCK

    Most of us don't get as much sleep as we should, which is often due to hectic weekday schedules. Åkerstedt et al. reveal that all is not lost—sleeping in on the weekends may have beneficial effects on our health. In a 13-year study of more than 43,000 subjects, the researchers compared the duration of sleep on weekdays versus weekends with overall mortality. Individuals (<65 years old) who caught less than 5 hours of sleep a night had a higher death rate than those that regularly had 7 hours of sleep. But when the weekday short sleepers compensated with long sleep on weekends, no difference in mortality was observed.

    J. Sleep Res. 10.1111/jsr.12712 (2018).

  6. Climate Change

    Warming in Greenland's past

    1. H. Jesse Smith

    To project how much sea level will rise in response to ongoing climate warming, one of the things we need to know is how sensitive the rate of Greenland Ice Sheet melting is to rising temperatures. McFarlin et al. present results from a set of sediment cores from a small nonglacial lake in the highlands of northwest Greenland, which contain deposits from the Holocene and the Last Interglacial (LIG). They found midge assemblages indicating peak July temperatures that were 4.0° to 7.0°C warmer than modern temperatures during the early Holocene and at least 5.5° to 8.5°C warmer during the LIG. This perspective of extreme warming suggests that even larger changes than predicted for this region over the coming century may be in store.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1720420115 (2018).

  7. Neuroscience

    The human prefrontal cortex is special

    1. Peter Stern

    The size and surface area of the cerebral cortex varies dramatically across mammals. It is well known that the human cortex is by far the largest among primates. However, there is no agreement about whether the human prefrontal cortex is larger, in relative terms, than those of other primates. Donahue et al. compared structural brain scan datasets from humans, chimpanzees, and macaques. They found a greater proportion of prefrontal cortex gray matter volume in humans than in the two nonhuman primate species, and they observed an even greater difference between species for white matter volume in the prefrontal cortex. This part of the association cortex, which is implicated in higher cognition and affect, is thus disproportionately large in humans relative to other primates.

    Proc. Natl. Acad. Sci. U.S.A. 115, E5183 (2018).