Articles in 2011

Most quantum communication experiments are performed at visible wavelengths, yet practical, long-range schemes need photons in the telecommunications range. Here, down-conversion of a visible photon to the near-infrared is demonstrated, while retaining its entanglement to another visible photon.

External electric fields have been used to control the motion of small objects through electrostatic repulsion. Here, electric fields are used to polarize conducting objects, triggering their movement by spatially separated electrochemical reactions leading to directionally controlled bubble evolution.

Photonic alternatives to electrical circuits require low energy demand and fast modulation speed, which has proven difficult for on-chip devices. Using quantum dot photonic crystal nanocavities, Vučkovićet al. demonstrate an electrically-switchable light-emitting diode with such capabilities.

The health benefits of massage therapy, like the reduction of stress, have so far only been shown in humans. This study uses modelling to demonstrate that, while visiting cleaner fish to have ectoparasites removed, the physical stimulation also acts to reduce stress in the coral reef fish,Ctenochaetus striatus.

Covalent organic frameworks form a porous skeleton with a precise pore size and geometry, but control of the pore surface is challenging. Here, a protocol is introduced for pore surface engineering of covalent organic frameworks, allowing the control of composition and density of organic groups in the pores.

Detecting bacteria in clinical samples usually requires culture processes that are time consuming and impede rapid diagnoses. Now, a surface-enhanced Raman spectroscopic method is reported that allows the label- and culture-free detection and analysis of bacteria.

Female Swallowtail butterflies will only lay their eggs on a small number of plants, which they choose by detecting specific chemicals on the leaf surface. Here, a gustatory receptor,PxutGr1, is identified in Papilio xuthus, which is used by the butterfly to detect synephrine when selecting a host plant.

DNA nanotubes could be used to transport nano-cargo and incorporated into nano-devices. In this study, rolling circle amplification is used to generate DNA subunits, and their thermodynamic growth results in the formation of nanotubes with a controlled diameter.

Metallic and semiconducting carbon nanotubes generally coexist in 'as-grown' materials. In this study, single-walled nanotubes are sorted using regioregular poly(3-alkylthiophene)s; rational selection of polymers, solvent and temperature allows the selective dispersion of semiconducting carbon nanotubes.

The methylation of DNA and histone H3 lysine 9 in chromatin are positively correlated. This study shows that the DNA methyl transferase Dnmt3a is methylated, and a crystal structure of Dnmt3a bound to the chromodomain protein MPP8 suggests a molecular mechanism.

Leaves and tissues contain three-dimensional networks of fluidic channels, but similar artificial self-assembling systems have not yet been produced. Jamalet al. develop methods to produce three-dimensional microfluidic networks with curved geometries from the self-assembly of photopatterned polymers.

The miniaturization of optical devices is crucial for their on-chip integration with a variety of technological applications. Here, Liuet al. present an ultracompact beam splitter to control the direction of light through the generation of surface plasmon polaritons.

Parasites such as malaria elicit an immune response in their host, causing cytokine levels to increase. In this study, a parasite housekeeping gene, tyrosyl-tRNA synthetase, is shown to bind to host macrophages and, once inside the cells, enhance the levels of proinflammatory cytokines.

The microRNA miR-137 is enriched in the brain of mice and induces the differentiation of adult neural stem cells. Now, Sun and colleagues report that miR-137 negatively regulates proliferation of neurons in embryonic mice and that TLX and LSD1 cooperate to negatively regulate miR-137 expression, blocking premature differentiation.

In the classical model, fast neuronal signalling occurs at specialized presynaptic terminals. Now, Ratnayakaet al. show that stimulus-driven fusion and recycling of synaptic vesicles can occur at axonal sites remote from conventional synapses. These findings have implications for dynamic forms of neuron–neuron communication.

Differences in the arrangement of cells is a fundamental precursor to the establishment of different organs. In this study, network theory is applied at the level of individual cells to map patterns in cell-to-cell contacts, creating a new approach to objectively characterise epithelia.

At light levels where both rods and cones are active, their signals converge into shared downstream retinal circuitry. Using HCN1 deficient mice, this study shows that the signals from cone photoreceptors are overwhelmed when rod output is not regulated, suggesting a mechanism for how these systems interact.

Controlling the magnetic properties of nanoparticles is important to enable their widespread use in applications. Antoniaket al. combine X-ray absorption spectroscopy and density functional theory calculations to uncover the origin of these properties in order to appropriately tailor nanoparticle design.

Cross-coupling reactions are widely used for creating new carbon–carbon bonds in chemical syntheses. Using the cross-coupling concept, Wang and colleagues present an organocatalytic strategy for the direct and stereoselective α-arylation of enals that occurs under mild conditions.

Surface characterization of soft materialsin situis challenging due to the importance of non-covalent interactions. Now, a new chemical imaging method is reported that generates images of surface interactions by combining many molecular probe trajectories.