Editors' Choice

Science  08 Apr 2016:
Vol. 352, Issue 6282, pp. 184
  1. Biophysics

    Going with the flow

    1. Gilbert Chin

    The shape of the oyster mushroom allows its spores to be carried out, up, and away

    PHOTO:© BLICKWINKEL/ALAMY STOCK PHOTO

    Low to the ground and immobile, mushrooms would seem to be physically challenged when it comes to dispersing their spores. Dressaire et al. demonstrate that they make use of their surroundings to propel their progeny out into the world. Water evaporating from the under-surface of the mushroom cap creates a temperature gradient. This produces a flow of air that is enhanced by the tilted orientation of the cap, and ejected spores are carried outward and upward by the breeze. Mushroom clusters help rather than hinder this flow.

    Proc. Natl. Acad. Sci. U.S.A. 113, 2833 (2016).

  2. Cell Migration

    Consumed by your own attraction

    1. Caroline Ash

    Cell migration is a fundamental biological phenomenon. Cells follow gradients of chemo-attractants whether generated by secretion or breakdown of other cells, or from diffusion of drugs or small molecules. Tweedy et al. investigated the possibility that cells can self-generate gradients by comparing observations of Dictyostelium cells grown under agarose containing folate as the attractant. Once Dictyostelium was added to a well cut into a sheet of folate-containing agarose, a dense leading edge of migrating cells soon formed that traveled under the agarose. Behind the front of directionally moving cells, cell activity was random, because the chemo-attractant had been completely consumed by the folate deaminase activity of the leading cells. This kind of cell behavior may be widespread and may explain the behavior of cells during development, cancer, wound healing, and immune responses.

    PLOS Bio. 10.1371/journal.pbio.1002404 (2016).

  3. Physics

    Making sense of transport in WSe2

    1. Jelena Stajic

    Among materials that have a structure similar to that of graphene, but without a band gap, transition-metal dichalcogenides—such as MoS2 and WSe2—are the most prominent examples. Much of what we know about their electronic properties has come from optical measurements; the more traditional transport experiments have proven trickier. Fallahazad et al. studied the behavior of electrons in monolayers and bilayers of WSe2 subjected to an external magnetic field. As they tuned the field, the researchers observed characteristic oscillations in the transport properties. Analyses of these oscillations suggested that the electrons' spin and valley degrees of freedom were tightly coupled at lower fields, and only uncoupled at the highest applied fields of about 30 T.

    Phys. Rev. Lett. 116, 086601 (2016).

  4. Climate Change

    Hiding in plain sight

    1. H. Jesse Smith

    Human influence on record-breaking heatwaves was apparent as early as the 1930s

    PHOTO: © JOSE LUIS CUESTA/CORDON PRESS/CORBIS

    As climate changes and global temperatures continue to rise, the effects of human activities on extreme weather events such as heat waves, droughts, and storms have become more clear. How long ago did our influence become discernable? King et al. report that a notable human contribution to record-breaking global heat waves can be seen as early as the 1930s. Since that time, all of the last 16 record-setting hot seasons or years globally have had a discernable anthropogenic component of their probability of occurrence. The authors point out that their approach could be extended to examine other high-impact extremes that were not record-breaking.

    Geophys. Res. Lett. 10.1002/2015GL067448 (2016).

  5. Organometallics

    A solid picture of rhodium carbenes

    1. Jake Yeston

    Students of organic chemistry learn early that carbon tends to engage four of its electrons in bonding. It is possible, nonetheless, to prepare carbenes—carbon centers with a pair of unbonded electrons—and to use metal coordination to help productively direct their high reactivity. Rhodium-coordinated carbenes have emerged as some of the most useful variety, and Werlé et al. now report crystal structures of several of them. Specifically, the authors characterized so-called “push-pull” varieties, in which the carbon bears an electron-donating and an electron-withdrawing substituent, at both Rh(II) and Rh(III) centers. The results support the currently favored model accounting for their stereochemical selectivity in reaction with C=C double bonds.

    J. Am. Chem. Soc. 10.1021/jacs.5b13321 (2016).

  6. Smart Cars

    Will smart cars mean ending street lights?

    1. BRJ

    One potential advantage of cars becoming smarter is that traffic might flow better. Tachet et al. have simulated the flow of traffic and compared a system in which the first vehicle to get to an intersection has priority, versus one in which a consistent flow of vehicles is maintained. They found that slot-based interactions, in which speed is controlled so that a vehicle does not enter the intersection until there is an opening available, work best. Paradoxically, slower movement can end up being faster because vehicles can cross in batches, without clumping together. The authors estimate that this system would double road capacity and result in fewer delays

    PLOS One 10.1371/journal.pone.0149607 (2016).

  7. Cancer Therapy

    A repackaged cancer drug finds its way

    1. Paula A. Kiberstis

    The recent success of immunotherapy has energized the clinical oncology field, yet for many cancer types, cytotoxic drugs remain the only treatment option. One such drug, doxorubicin (Dox), is very effective but also very toxic to healthy tissues when administered at the doses needed to kill tumor cells. To target delivery of the drug, Xu et al. developed a “nanoparticle generator” (iNPG) containing a polymeric form of Dox. The design features of iNPG ensure that it selectively accumulates at the tumor and that release of Dox is slow and sustained, resulting in high drug concentrations within the tumor. In mouse models of breast cancer, iNPG induced regression of lung metastases and was less toxic than other forms of Dox.

    Nat. Biotechnol. 10.1038/nbt.3506 (2016).