Several weeks later, although hearing sensitivity had recovered to normal levels, activity in the auditory nerve connecting the inner ear to the brain remained impaired.

BBC: Viewpoint: Does deafness contribute to dementia?

The number of channel molecules present means that, in normal circumstances, about 70% of the free-floating outer channels are lined up with tethered inner ones at any given time, with each dual channel letting through about 1m sodium ions per second.

ECONOMIST: Medical diagnostics

"If there is only a problem in its inner layer, it may be possible to replace just that part of the cornea, leaving the patient's normal and healthy tissue in place, " said Mr Muhtaseb, a Singleton-based consultant ophthalmologist.

BBC: New eye surgery shortens recovery