Strategies to engineer microorganisms to produce medium-chain hydrocarbon chemicals are reviewed.

In this Review, a group of experts in fragile X syndrome analyses why the considerable drug development effort based on robust preclinical findings describing the mechanisms underlying this neurodevelopmental disorder has failed to translate into effective treatment and offers possible solutions to improve clinical trial design and therapeutic approaches.

It is challenging to exploit anionic redox activity to boost performance of battery electrodes, especially for anti-fluorite structures. Here the authors report simultaneous anionic and cationic redox in Li₅FeO₄, which enables its high capacity and eliminates the undesired oxygen gas release.

Hydropower is critical to eastern and southern Africa but it is at risk from climate variability. Conway et al. examine river basins and rainfall variability to explore potential hydropower disruption for present and planned generation sites, highlighting the risks to supply and their spatial interlinkages.

Cation engineering has been used to tune the efficiency and stability of perovskite solar cells. Here, Jodlowski et al. introduce guanidinium, a cation slightly larger than previously thought possible, mixed with the traditional methylammonium cation, into the 3D structure, improving device stability.

Anionic redox provides extra capacity for battery electrodes, but it is challenging to realize its full potential. Tarascon and colleagues report a record-high reversible capacity of 3.5 electrons per Ir in a Li₃IrO₄ phase, and discuss the importance of increasing the ratio of oxygen versus transition metal.