"We don't really understand the signaling mechanisms that stem cells rely on yet," Snyder says.

Conventional solar cells rely on silicon crystals, and energy conversion is around 10 per cent.

"After other parts of the cell have broken down, the cell relies on p53 as a last way to keep it in check."

When an error occurs in the DNA of a gene, cells rely on an error-specific repair mechanism to knock out the errant information.

For instance, some solar cells rely on the photovoltaic properties of semiconductors to convert light to electricity.

These multilevel cells have problems and rely on error correction, very much in the same way that bits are soft in the magnetic storage of a hard drive.

He and other researchers say that cells rely on natural fatty acids to function.

While stable operation has been achieved on a variety of hydrocarbon fuels, these cells typically rely on external fuel processing.

Bipolar cells rely on a different mechanism.

The cells were grouped around a central flue which led to considerable fuel economies but was labour intensive and relied on separate slurry drying facilities.