Articles

The fractional quantum Hall effect occurs when electrons move in Landau levels. In this study, using a theoretical flat-band lattice model, the fractional quantum Hall effect is observed in the presence of repulsive interactions when the band is one third full and in the absence of Landau levels.

Covalent reactions on carbon nanotube surfaces typically occur at random positions on the hexagonal lattice. Denget al. show that Billups–Birch reductive alkylation takes place at, and propagates from, sp³defect sites, leading to confinement of the reaction fronts in the tubular direction.

Optical computing, involving on-chip integrated logic units, could provide improved performance over semiconductor-based computing. Here, a binary NOR gate is developed from cascaded OR and NOT gates in four-terminal plasmonic nanowire networks; the work could lead to new optical computing technologies.

Iron pnictide compounds have recently been shown to have superconducting properties. Xuet al. show that the superconducting gap of underdoped pnictides scales linearly with the transition temperature, and that a pseudogap develops with underdoping.

Tissue regeneration is of great interest; however the number of times a given tissue can regenerate is unknown. Now, Eguchiet al. demonstrate that the lens of the Japanese newt—Cynops pyrrhogaster—can regenerate 18 times over a 16-year period, and that the new lenses are similar to those of control adult animals.

Thioredoxin reductase 1 is a flavoprotein that is involved in the regulation of redox homeostasis. Fritz-Wolfet al. report the first crystal structures of thioredoxin reductase 1 in complex with its substrate, thioredoxin, and confirm that the enzyme uses a flexible carboxy-terminal arm for electron transport to its substrates.

Group-1 influenza A neuramidase proteins have a 150-cavity that can be targeted by drugs, but the 2009 H1N1 virus neuramidase is not thought to have a 150-cavity. Here, biophysical simulations show that the 2009 H1N1 neuramidase exists in solution with an open 150-cavity, which is stabilized by a salt bridge.

During development, Wnt-mediated Notch signalling controls the generation of somites from the presomitic mesoderm, but the precise signalling mechanism is unknown. Here, the transcription factor Mesogenin 1 is shown to be a direct target of Wnt3a and regulates the transcription of a Notch signalling program.

The torsinA protein localizes to the endoplasmic reticulum and, when mutated, causes early onset torsion dystonia. The authors reveal a new role for torsinA in proteosome-mediated degradation of misfolded proteins, and relate this to endoplasmic reticulum stress, in aCaenorhabditis elegansmodel and patient fibroblasts.

von Willebrand factor (VWF) multimers mediate primary adhesion and aggregation of platelets. Jakobiet al. reveal a calcium-binding site in the VWF-A2 domain, and show that calcium binding encourages folding of the protein and has a role in mechanosensing.

Studying how pathogens enter polarized epithelial cells is important for understanding infection. Here, activation of chemokine receptors on the apical membrane of epithelial cells, is shown to engage Src family tyrosine signalling, resulting in relocation of the viral co-receptor αvβ3 to the apical membrane and adenovirus entry.

Soluble cytosolic proteins can be degraded in lysosomes by chaperone-mediated autophagy, however, the current method to measure this process requires isolation of lysosomes. Now, a fluorescent reporter is described that can measure this type of autophagy in intact cells.

A quantum simulator can follow the evolution of a prescribed model, whose behaviour may be difficult to determine. Here, the emergence of magnetism is simulated by implementing a quantum Ising model, providing a benchmark for simulations in larger systems.

Two-qubit operation is an essential part of quantum computation, but implementation has been difficult. Gotoet al.introduce optically controllable internuclear coupling in semiconductors providing a simple way of switching inter-qubit couplings in semiconductor-based quantum computers.

Interactions between charge, orbital and lattice degrees of freedom in correlated electron systems have resulted in predictions of new electronic phases of matter. Carlson and Dahmen propose two protocols for detecting disordered electron nematics in condensed matter systems using non-equilibrium methods.

Studies of male genitalia show patterns of divergent evolution, whereas females have been less well studied. Using experimental evolution and quantitative genetic analysis, Simmons and Garcia-Gonzalez show that sexual selection drives the coevolution of female and male genital morphology in the dung beetleOnthophagus taurus.

The construction of three-dimensional hierarchical heterostructures can lead to improved electrochemical properties. Maiet al. synthesize a three-dimensional multicomponent oxide, MnMoO₄/CoMoO₄, which is used to produce a supercapacitor with enhanced performance.

The sigma-2 receptor is used as a biomarker for tumour cell proliferation but its identity is unknown. Using a novel radiolabelled probe, the authors identify progesterone receptor membrane component 1, which is overexpressed in several tumour types, as the putative sigma-2 receptor.

Archaea are microorganisms that use a wide range of carbon and energy sources. Grahamet al. describe an archaeal consortium that can grow at temperatures above 90 °C using crystalline cellulose as a carbon source, with potential applications in enzymatic degradation under extreme conditions.

Ambient levels of the neurotransmitter GABA tonically activate GABA_A. Song et al.show that GABA can have both excitatory and inhibitory effects on hippocampal interneurons and find that low levels of GABA-mediated conductance are excitatory, whereas higher levels result in shunting inhibition.