Acid-sensing ion channels (ASICs) are voltage-independent ion channels that participate in a broad range of biological processes, including nociception and mechanosensation; here X-ray crystal structures of the complexes of chicken ASIC1a with psalmotoxin, a peptide toxin from tarantula, indicate that toxin binding triggers an expansion of the extracellular vestibule and stabilization of the open channel pore.

A free-electron laser is used to power a pulsed electron paramagnetic resonance spectrometer at 240 GHz, demonstrating a range of experimental possibilities such as the manipulation of spin-1/2 systems with 6-ns pulses and the measurement of ultrashort decoherence times.

Here, the feedback between marine nitrogen fixation and denitrification is shown to yield an oceanic nitrate deficit more than double its observed value in a model with realistic ocean circulation; this discrepancy can be resolved by accounting for diversity in the metabolic N:P requirements of plankton.