Lack of an adequately strong bone structure can lead to higher incidence of osteoporosis, in which bones become increasingly porous and brittle, after age 45.

More may follow as music's borders become increasingly porous.

The computers that tie together the Government's information systems have become increasingly porous.

Or do critics now have a duty to know about everything from music to performance art, as different disciplines become increasingly porous?

They also appear impotent to stem the flows of migrants across their increasingly porous borders.

Even before Hong Kong reverted to Chinese rule in 1997, the border between the two had become increasingly porous.

But, as the borders between states became increasingly porous, people moved in search of employment, to build businesses or, simply, because they could.

China is increasingly porous to news and ideas, and its high-tech political ferment goes beyond online debates.

Pressure on the Serbs has consisted of economic sanctions that have grown increasingly porous; the Croats have received little more than words of warning.

As a result, they have become increasingly porous, permitting electric current - and heat - to cascade out even when they are switched off.