Articles in 2012

The collective gyrotropic excitation of an array of spin vortices has frequencies that depend on the polarities and chirality of individual vortices. This work demonstrates control of the spectral response of the system by tuning the excitation frequency or the external magnetic field.

During embryonic development, midline fluid flow results in asymmetric nodal gene expression. Using genetic manipulations and mathematical modelling, Nakamura et al. find that expression of the nodal antagonist Cerl2 is regulated post-transcriptionally, and that asymmetry is maintained by Wnt-Cerl2 feedback loops.

The flow of calcium into the mitochondrial matrix is mediated by the mitochondrial calcium uniporter. Fieniet al. apply patch-clamp techniques to mitoplasts isolated from different mouse and Drosophilatissues and find that the mitochondrial calcium uniporter activity varies depending on the tissue studied.

Plants such asArabidopsishave evolved genetic adaptations to their geographic location. Here, a network-based approach is applied to study the link between geographic location and heterogeneous molecular phenotypes, revealing a pattern of isolation by distance in genotypic variability, flowering and metabolic phenotypes.

In quantum communication, the noisy-storage model assumes that an attacker’s memory device is imperfect, thus enabling two parties to implement protocols securely. Using polarization-entangled photon pairs, Ng et al.analyse and verify a two-party bit commitment protocol within the noisy-storage.

Levels of extracellular calcium can increase at sites of infection and inflammation; however, the physiological significance of this has been unclear. This work shows that extracellular calcium acts as a danger signal, triggering the NLRP3 inflammasome via two G protein-coupled receptors.

PAR-1 inDrosophilahas been identified as a key physiological tau kinase. Lee and colleagues perform genetic screens for regulators of PAR-1 and find that it is targeted for ubiquitination and degradation by the ubiquitin ligase complex SCF(Slimb), and that this pathway modulates synaptic morphology.

The design and assembly of nanostructures exhibiting ferromagnetic hysteresis at room temperature are recognized goals for high-density data storage. Here, the authors engineer nanostructures with atomically sharp bimetallic interfaces and interlines, which exhibit large magnetic anisotropy and high temperature hysteresis.

The heterogeneity of cortical interneurons results from spatio-temporal differences in embryonic origin. Marissal et al. show that early-generated glutamatergic neurons display distinct morpho-functional features, suggesting that temporal factors are also important in determining glutamatergic function.

The Prunus mume was domesticated in China over 3,000 years ago and is an important ornamental plant and fruit. Here Qixiang Zhang et al.obtain the first assembly of its genome with a combination of next-generation sequencing, whole-genome mapping and restriction-site-associated DNA.

A full understanding of the heating and dynamics of the Sun's atmosphere remains elusive, but magnetohydrodynamic waves are believed to be crucial. Using observations from the ROSA imager, this study finds compressive waves in the solar chromosphere, which may provide the energy needed for coronal heating.

How the genome is physically organized is less understood in archaea than in eubacteria or eukaryotes. Laurens et al. measure DNA binding by the Sulfolobus solfataricusproteins Alba1 and Alba2 using single-molecule techniques and conclude that the presence of Alba2 leads to more bridging between DNA.

For the ultrasensitive detection of magnetic fields either atomic transitions or superconducting circuits are used. Bal et al. combine such approaches and demonstrate a superconducting device functioning as an artificial atom for magnetic field detection with high sensitivity and spatial resolution.

In vitro, retroviruses spread between cells via structures resembling synapses. Sewaldet al. now demonstrate that virological synapses can also be observed in living mice by intravital microscopy, validating this concept in vivo.

High-efficiency and high-speed single-photon detectors are vital for quantum optical technologies. Using superconducting nanowire detectors on nanophotonic waveguides, Pernice et al.demonstrate on-chip single-photon detection efficiencies up to 91% at telecommunications wavelengths.

The conversion efficiency of organic solar cells depends on the shape of the interface between their donor and acceptor components. Liuet al. demonstrate a scalable method using crosslinked polymer networks to fabricate the finely interpenetrating structures needed to achieve near-perfect internal quantum efficiency.

The rise of open-habitat ecosystems in southern South America is thought to have occurred with the spread of hypsodont mammals 26 million years ago. In this study, the fossil record of plants preserved in Patagonia suggests that open-habitat ecosystems emerged 15 million years later than previously assumed.

Half-quantized vortices are the fundamental topological excitations of a two-component superfluid, however, probing the dynamics of their formation is challenging. Manni et al.report real-time observations of polariton vortices unbinding into half-quantized vortex pairs in an exciton-polariton condensate.

There are only a few known organic ferroelectrics, particularly ones that operate at high temperatures. Here the discovery of ferroelectricity above room temperature in members of an ubiquitous family of organic molecules reveals the possibility of novel low-cost electronic applications.

One of the many exotic characteristics of systems that exhibit the fractional quantum Hall effect is the presence of chiral edge modes that carry energy but no net charge. Gurman et al.demonstrate the use of quantum dots to transform this energy into a measurable current, enabling them to better probe these modes.