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The colour centre platform holds promise for quantum technologies, and hexagonal boron nitride has attracted attention due to the high brightness and stability, optically addressable spin states and wide wavelength coverage discovered in its emitters. However, its application is hindered by the typically random defect distribution and complex mesoscopic environment. Here, employing cathodoluminescence, we demonstrate on-demand activation and control of colour centre emission at the twisted interface of two hexagonal boron nitride flakes. Further, we show that colour centre emission brightness can be enhanced by two orders of magnitude by tuning the twist angle. Additionally, by applying an external voltage, nearly 100% brightness modulation is achieved. Our ab initio GW and GW plus Bethe-Salpeter equation calculations suggest that the emission is correlated to nitrogen vacancies and that a twist-induced moiré potential facilitates electron-hole recombination. This mechanism is further exploited to draw nanoscale colour centre patterns using electron beams.

To resolve severe constipation or faecal impaction requires the induction of a large increase in faecal water content that hitherto has only been achieved with enemas. A novel iso-osmotic laxative has been shown to achieve a similar effect from oral dosing.

The effects of prostaglandin E1 (PGE1) on myocardial ischaemia (as measured by epicardial ST segment changes), myocardial flow and substrate exchange has been studied in dogs. Myocardial ischaemia was induced by intermittent external clipping of a branch of the left anterior descending coronary artery. During occlusion with a continuous intravenous infusion of isoprenaline, elevated epicardial ST segments (∑ST), were raised to 46 ± 6 mV (mean ± SEM). Pretreatment with PGE1 reduced ∑ST to 34 ± 6 mV (P