1.   The house is kept in almost total darkness with a special membrane to block out ultra-violet light covering all the windows.

2.   You have to play with a special membrane, made of v. thin bamboo, over one of the holes.

3.   Each organ or type of tissue in the body is contained in a special membrane, a kind of sac.

4.   In reverse osmosis, the sap is forced under high pressure through tubes lined with a special membrane that allows water to flow through but blocks molecules of sugar.

5.   The biggest remaining hurdle is lowering the high cost of fuel cell components, including special membranes, polarized plates and platinum-loaded electrodes.