It has long been known that ice starts melting at temperatures far below its nominal freezing point, but why or how has remained enigmatic. An innovation in atomic force microscopy provides insights into how this process begins in the most abundant form of ice on Earth.

Myelin is a fatty substance that forms an insulating sheath around the axons of neurons. In mice, drugs of abuse induce neuronal-activity-regulated changes in the myelination of neurons in the brain’s reward circuitry that release the neurotransmitter chemical dopamine. This myelin plasticity is required for the learning of reward associations with drugs of abuse, such as morphine.

A laser technique, which has a time resolution of only a few femtoseconds, captures how photoexcited electrons can influence the chirality — or handedness — of neutral molecules. The resulting helical currents could be used to control physical and chemical properties that result from chiral interactions. This technology could have applications in fields ranging from solid-state electronics to drug design.

Using tissue from the developing fruit-fly wing, researchers show that a nucleus’s location in the cell determines how it experiences signals that regulate genes needed for proper wing formation.