This Week in Science

Science  12 Aug 2011:
Vol. 333, Issue 6044, pp. 800
  1. Not Even Skin Deep

    Fixing electronics onto skin typically involves the attachment of bulk electrodes using adhesive tapes, mechanical clamps or straps, or penetrating needles. Kim et al. (p. 838; see the Perspective by Ma) designed filamentary serpentine electronic circuits that encompass very thin functional components encased in a flexible polymer that can be attached to the skin by using noninvasive van der Waals contacts. As a result of this technology, components and devices were produced for physiological status monitoring, wound measurement and treatment, human-machine interfaces, and covert communications.

  2. Cooling Aerosols

    CREDIT: SOLOMON ET AL.

    Our climate has warmed substantially over the past half-century, mostly owing to the addition of greenhouse gases to the atmosphere. However, the rate of warming has not been constant: Average global temperature has been increasing less quickly over the past decade than during the 1980s and '90s. Solomon et al. (p. 866, published online 21 July) used ground-based and satellite measurements of stratospheric aerosol burdens to reconstruct the amount of radiative forcing that aerosols have provided over the past 50 years. Since 1998, global temperatures increased by about 25% less than if the amount of stratospheric aerosols had not increased. Stratospheric aerosols also provided a slight cooling effect between 1960 and 1990.

  3. Twice as Nice

    An important goal in public health is the development of a universal influenza vaccine. Broadly neutralizing antibodies against group 1 influenza A virus have been described; however, a broadly neutralizing antibody against group 2 viruses has not (see the Perspective by Wang and Palese). Ekiert et al. (p. 843, published online 7 July) describe the isolation and characterization of a human monoclonal antibody, CR8020, with broadly neutralizing activity against group 2 viruses, which recognizes a region distinct from that recognized by the group 1 antibodies. In a separate study, Corti et al. (p. 850, published online 28 July) report the isolation of an antibody from an influenza-infected individual that shows neutralizing activity against both group 1 and group 2 influenza A viruses. The antibody binds to a conserved region in the influenza hemagglutinin. Administration of the antibody protected both mice and ferrets against infection with a group 1 or group 2 influenza A virus.

  4. Supernova Surrounded

    Type Ia supernovae are thought to be produced by an explosion of a white dwarf star that accretes matter from a companion star in a close binary system: According to current models, this companion can be either another white dwarf or a normal or giant star. One feature that distinguishes these models is the presence of circumstellar matter when the companion star is not a white dwarf. Sternberg et al. (p. 856) looked for signatures of circumstellar matter in 35 type Ia supernovae and concluded that in nearby spiral galaxies, type Ia supernovae tend to originate from a binary system containing only a single white dwarf.

  5. Rapid Cortical Memory Consolidation

    Systems memory consolidation, in which hippocampus-dependent memory is taken over by cortical areas, has traditionally been thought to be a slow process. When rats are trained in a paired-associate memory task and learn a new paired-memory association in the same context, formation of the new event memory requires the hippocampus. However, recall rapidly becomes hippocampus independent, suggesting that systems memory consolidation can occur quickly if an associative schema has already been created. Tse et al. (p. 891, published online 7 July) use the same behavioral paradigm to now show parallel memory encoding in the neocortex during hippocampal-dependent learning of new paired-associate memory traces into an existing cortical schema. This parallel encoding was essential for subsequent memory.

  6. Electron Correlations in Bilayer Graphene

    The electronic properties of many materials are well described by a “single electron” model because the effects of electron-electron interactions are blurred by the scattering at defects or thermal broadening. Mayorov et al. (p. 860, see the cover) were able to find evidence of electron correlations in suspended bilayer graphene samples that had been prepared to remove defects and dopants and to increase their quasiparticle mobility.

  7. The Right Receptor for Attention

    Release of the neurotransmitter acetylcholine from the basal forebrain cholinergic system is essential for sensory processing and cognition. Guillem et al. (p. 888) now describe a key role for β2-subunit–containing nicotinic acetylcholine receptors (nAChRs) in visual attention. Mice lacking the β2 subunit exhibited impaired attentional performance. The deficit was recovered, however, by the reexpression of a β2-nAChR in the medial prefrontal cortex. Furthermore, in brain slices, the response of medial prefrontal cortical cells was abolished with a β2-nAChR antagonist and reinstated after washout. Attention is thus controlled by acetylcholine acting on the expression of β2-nAChR in the neurons of the medial prefrontal cortex.

  8. My One and Only

    CREDIT: S. ABRAMOWICS/DINOSAUR INSTITUTE, NHM

    Plesiosaurs have been known for nearly 200 years and are well represented in the fossil record; however, little is known about their natural history. O'Keefe and Chiappe (p. 870) reexamined a nearly 30-year-old Plesiosaur fossil of Polycotylus latipinnis and suggest that this group was viviparous. In contrast to other viviparous Mesozoic marine reptiles, P. latipinnis produced only a single large offspring, which may suggest that Plesiosaurs engaged in high levels of maternal care for their offspring. The low number of offspring produced may also have contributed to the rarity of neonate Plesiosaurs in the fossil record.

  9. Hydrogen in a Hurry

    Bringing together two protons and two electrons to form the simplest molecule—hydrogen—is deceptively challenging. Helm et al. (p. 863) synthesized a stripped-down catalyst that features just a nickel ion and two heptagonal amino-diphosphine ligands, yet manages to couple protons in acidic acetonitrile solution reductively at a turnover frequency exceeding 100,000 cycles per second. Structural and kinetic studies of this complex and its variants implicate a conformation that places the amines in just the right orientation to transfer protons to the reduced nickel center.

  10. Not Going It Alone

    When breeding in insects is limited to few individuals in a group, the evolution of eusociality is often explained by kin selection. What, then, explains nonrelated individuals in insect colonies? Leadbeater et al. (p. 874; see the Perspective by Gadagkar) examined the founding of colonies of the wasp Polistes dominulus, where nests are often established by both dominant (breeding) and subordinate foundresses (primarily nonbreeding). The presence of unrelated individuals was associated with more successful establishment and maintenance of a colony, when compared with those established by a single foundress. The potential to inherit the nest thus resulted in a higher probability of reproductive success for subordinates than had they established their own nest.

  11. Fungal Placement Resolved

    CREDIT: ANNA ROSLING

    Fungi play important roles in nature, but many taxa remain uncultured, known only from environmental DNA sequences with uncertain phylogenetic placement. Rosling et al. (p. 876) have now cultivated and sequenced two representatives of a clade previously designated as Soil Clone Group I and identified it as a new class within the Ascomycota—Archaeorhizomycetes. Archaeorhizomycetes may be present in soil in forests and grasslands from the tundra to the tropics.

  12. You Scratch My Back …

    Plants and arbuscular mycorrhizal fungi often form mutualistic associations that provide the plant with mineral nutrients and the fungi with carbohydrates. When multiple plants and fungi are associated, how is nonreciprocal nutrient exchange prevented? Kiers et al. (p. 880; see the Perspective by Selosse and Rousset) manipulated the associations between plants and more- and less-cooperative fungi and traced the movement of resources between the plant roots and fungi. Nutrient exchange could be explained by both the plant and fungus making nutrient availability dependent on the nutrient output it receives from the partner, with the best partners being given more resources.

  13. Motor Lockdown

    Kinesin-1 is a dimeric molecular motor that transports cargo on microtubule tracks. Its movement is dependent on adenosine triphosphate hydrolysis and, when not transporting cargo, it is autoinhibited. Autoinhibition involves binding of the tail region to the motor domain, but the precise mechanism is unclear. Based on the crystal structure of a motor domain dimer in complex with a tail domain, Kaan et al. (p. 883) show that the tail domain binds both motor domains and prevents the movement that is necessary for adenosine diphosphate release.

  14. Gametes Ahoy

    The development of gametes is controlled by the germ cells' own genome, as well as by signals from the surrounding somatic tissue that forms the gonads. In Drosophila, the primordial germ cells are first formed at the posterior pole of the embryo. Gastrulation moves the cells around, and the primordial germ cells must migrate to the gonads. Hashiyama et al. (p. 885, published online 7 July; see the Perspective by Van Doren) now show that the Sex lethal (Sxl) gene is expressed in female cells as they migrate. Expression of Sxl directs a female's fate by driving unusual expression of Sxl in genotypically male germ cells. Thus, in female Drosophila, oogenesis begins even before the germ cells find the gonads.

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