Milk, liver, peanuts and eggs also are naturally rich in choline, and studies have shown that it seems to play a role in metabolism, cell structure to the workings of brain neurotransmitters.

MSN: Some so-called 'dude foods' may not be so bad

The other, which faces a specialised type of solar cell made of a material called indium gallium arsenide, is sculpted into a structure called a photonic crystal that causes it to emit infra-red radiation selectively at the frequency best absorbed by the cell.

ECONOMIST: Solar power

At this stage the structure, though still just a featureless ball of cells, has started to differentiate into the body's three basic cell types (known as endoderm, mesoderm and ectoderm).

ECONOMIST: An embryonic development