Articles in 2011

Studying carrier multiplication in materials is important to understand their transport properties and interaction with light. Hiroriet al. show that intense terahertz pulses can generate electron-hole pairs in GaAs quantum wells that then emit infrared light, contrary to the effect with a DC field.

Ferroelectric materials are characterized by a spontaneous polarization, which in practical applications is manipulated by an electric field. This study examines how defects affect the switching with atomic resolution, by usingin situaberration-corrected transmission electron microscopy.

When materials change temperature as a result of the application of pressure or a change in the magnetization, they are said to display a barocaloric or magnetocaloric effect, respectively. This study reports a substantial barocaloric effect in the giant magnetocaloric material LaFe_11.33Co_0.47Si_1.2.

The habitat where early humans, hominins, lived provides information about the early part of human evolution. In this study, sedimentological and stable carbon and oxygen isotope data suggest homininArdipithecus ramiduslived in a river-margin forest in a wooded grassland landscape at Aramis, Ethiopia.

Membrane repair of myocytes is important to prevent such disease as muscular dystrophy but the properties of this repair are not well characterised. In this study, vitamin E is shown to be important in the repair of myocyte cell membranes in cultured cells and in intact muscle.

The tumour suppressor BRCA1 is mutated in familial breast and ovarian cancer. Now, Shuklaet al.demonstrate that mice lacking BRCA1 in cardiomyocytes are more sensitive to ischaemia than control mice, and that BRCA1 is elevated in human tissues exposed to ischaemia, suggesting a cardioprotective role for BRCA1.

Food availability elicits behavioural and developmental responses. Adamset al. show that, in sea urchin larvae, food availability mediates developmental plasticity by regulating changes in arm length through dopamine signalling, a pathway widely used to mediate food-induced behavioural responses.

G-protein-coupled receptors sense extracellular cues and transmit the signal to distinct trimeric G-proteins. Stefanet al.show that in response to cAMP, a central and conserved component of the Gαs-coupled receptor cascade, the RII subunit of PKA, specifically binds to and participates in Gαi signaling.

The tumour microenvironment is often found to be immunosuppressive. Reppert and colleagues show that human and murine lung tumours harbour IL-17A-producing T cells, and that blocking IL-17A increases survival in mice, suggesting that anti-IL-17A therapy may be useful in treating lung cancer.

At present there are no highly effective vaccines forPlasmodium falciparum. In this study, a vaccine raised against the P. falciparum reticulocyte-binding protein homologue 5 is shown to induce an IgG response in rabbits that could block the proliferation of multiple parasite strains in vitro.

Topological insulators are a class of materials with an unusual band structure that makes them metallic at the surface and insulating in the bulk. Okamoto and co-workers use electronic structure calculations to predict a new family of possible topological insulators based on transition-metal oxides.

Prenucleation clusters have been observed during the early stages of calcium carbonate formation, contrary to classical models. Here, computer simulations indicate that the clusters are composed of an ionic polymer with alternating calcium and carbonate ions, and a dynamic topology of chains, branches and rings.

The half-life of IgG is regulated by binding to the neonatal Fc receptor and, in the case of IgG3, is reduced compared to other IgG proteins. In this study, a mutation in IgG3 is shown to reduce binding to the neonatal Fc receptor, which can be competitively blocked by IgG1.

Optical vortex traps are appealing for handling delicate particles, but conventional techniques are challenging with objects smaller than the diffraction limit of light. By exploiting plasmonic resonances in gold diabolo nanoantennas, Kanget al. demonstrate low-power vortex trapping of nano-scale objects.

Biomass-derived monomers are a renewable resource for the production of polymers. Robertet al. develop an auto-tandem catalytic transformation for the synthesis of aliphatic polyesters—'activated' monomers are prepared from dicarboxylic acids, which can be copolymerized with epoxides.

The modification of proteins with O-linked-N-acetylglucosamine causes regulation of multiple cellular processes. In this study, Sakaidani and colleagues identify an endoplasmic reticulum O-linked-N-acetylglucosamine transferase in Drosophilathat regulates the adhesion of epithelial cells to the extracellular matrix.

Encephalization—increase of brain size relative to body size—has occurred in two distinct evolutionary lineages; Neanderthals and modern humans. However, the 3D endocranial surface shape analysis reported here reveals unique structures at the base of the brain inHomo sapiens, which may have contributed to learning and social capacities.

Mid-infrared semiconductor lasers suffer from a high threshold power density, but interband cascade lasers may offer a more efficient alternative. Here, theory and experiments on such emitters demonstrate remarkably low thresholds and power consumption compared to state-of-the-art quantum cascade lasers.

Genome-scale metabolic models for bacterial species allow a systematic study of inter-species interactions. Here, competitive and cooperative potential is predicted between 6,903 pairs of species, to explore the role of these interactions in shaping coexistence patterns in natural communities.

Optical imaging and spectroscopy rely on understanding how light enters and propagates through turbid media, yet its behaviour near the point-of-entry has remained elusive. Now Vitkinet al. report an analytical solution to this problem and demonstrate its agreement with simulations and experiments.