Articles in 2010

Although hyperlenses made of metamaterials can image sub-diffraction-limited objects, they are limited to one-dimensional magnification and ultraviolet frequencies. Here, the authors demonstrate a spherical hyperlens for visible light far-field imaging, with a resolution of 160 nm in both lateral dimensions.

Polycrystalline substrates are a hindrance to the realization of high-definition plasmonic nanostructures. In this paper the authors chemically grow large and thin gold single crystals, and show that they can be coupled with top-down fabrication methods to produce high-quality nanostructures with good optical properties.

The replication of viral genomes in infected cells is required for successful infection. In this study, using Cre-conditional expression of multiple coloured fluorophores, the authors demonstrate that the number of viral genomes expressed and replicated in a cell is surprisingly limited.

Direct quantum state tomography—deducing the state of a system from measurements—is mostly unfeasible due to the exponential scaling of measurement number with system size. The authors present two new schemes, which scale linearly in this respect, and can be applied to a wide range of quantum states.

Cryptophane-A is a prototypical organic host molecule that binds reversibly to neutral guest molecules. Taratulaet al.report X-ray structures of cryptophane-A complexed with a range of host molecules to show that the cryptophane host–guest system exhibits ‘induced fit’.

Deformations in nanocrystals smaller than 10 nm are not well understood. The authors perform compression high-resolution transmission electron microscopy studies of gold nanoparticles, and determine that the nanoparticles deform through the emission of partial dislocations from free surfaces.

Macroautophagy involves remodelling of intracellular membranes, but the role of lipids and lipid enzymes in this process is poorly understood. Here, the authors demonstrate that phospholipase D1, an enzyme that catalyses the production of phosphatidic acid, has a modulatory role in the autophagy process in mammalian cells.

Up to 20% of bacterial genomes are made up of cryptic prophages, but their function is relatively unknown. In this study, the authors demonstrate that prophages influence the response of the host cell to stress and provide a competitive growth advantage in the presence of antibiotics.

The integration of microarray and metabolite data is important for understanding the physiology of model organisms. This study demonstrates how the integration of these kinds of data can provide novel insights into the growth and protein metabolism of two different yeast strains.

Molecular fluctuations are a source of noise that can impede single-molecule identification. Here, quantum-fluctuation-induced inelastic noise is observed as current fluctuations in individual molecules, suggesting that inelastic noise could be used as a molecular signature.

In high-temperature superconductors, a very low density of states, the pseudogap, exists even above the critical temperature. Here, the authors show that this is also the case for a conventional superconductor, titanium nitride thin films, and that this pseudogap is induced by superconducting fluctuations.

Two principles have recently been proposed as attempts to provide physical axioms for quantum mechanics: causality and macroscopic locality. Cavalcanti and colleagues show here that the two are not equivalent, giving confidence in information causality as a constraint for correlations obtained in experiments.

Signal processing by time reversal has thus far only been realized through nonlinear mechanisms. The authors describe an all-linear, and thus low-power, time-reversal process based on frequency inversion in a dynamically controlled artificial periodic structure, a dynamic magnonic crystal.

Identifying the transcripts and proteins that fluctuate in response to stimuli provides important information for understanding cell physiology. In this study, 52% of theBacillus subtilispredicted proteome is identified following glucose starvation, revealing further insight into protein dynamics at a global scale.

Hydrogen production using photosynthetic bacteria is an appealing energy source, but typically the bacteria require anaerobic conditions. Here, the authors report a wild-type cyanobacterium strain that shows very high rates of hydrogen production under aerobic environmental conditions.

Materials such as rubber tend to soften when cyclically deformed. Here, however, the authors find that bundled actin networks can show cyclic hardening and retain a memory of the maximum strain they have been subjected to.

A single gene results in either dextral or sinistral snail shell coiling and snails with different coils cannot copulate. Here, the authors provide evidence of how such an allele can become fixed in a population by showing that snails with a counterclockwise sinistral coil are protected from predators.

Bacteria express adhesive proteins on their surface that recognize fibronectin. Using a mechanical stretch assay and steered molecular dynamics, Chabriaet al. demonstrate that the binding of a bacterial adhesin to fibronectin is mechanoregulated, suggesting that bacteria can sense tissue fibre stretching.

Topological insulators are materials with an insulating interior and a metallic surface. In this study the authors demonstrate that the topological state can coexist with a two-dimensional electron gas state, a feature important in semiconductors used for electronic applications.

γ-Secretase modulators have promise in the treatment of Alzheimer's disease, but their molecular target is uncertain. Here, fluorescence resonance energy transfer is used to determine that the γ-secretase allosteric site is within the γ-secretase complex and that substrate docking is required for modulators to access the site.