21.   But tiny particles of dirt, which have a molecular structure similar to ice, were present in the atmosphere.

22.   But they only treat the problem instead of preventing it, said Brittle, who is concerned about the chemical composition of tiny particles.

23.   But when this process goes awry, small numbers of misfolded proteins accumulate into tiny spherical particles inside cells.

24.   Chocolate, like sugar, is composed of tiny solid particles, which are suspended in cocoa butter.

25.   Clinton yesterday approved a plan to toughen air-quality standards and begin measuring these tiny particles.

26.   Currently, chipmakers spend effort and money trying to control the behavior of electrons -- the tiny particles of matter chips use to attract and hold data.

27.   Consider buying a High Efficiency Particulate room air filter, which helps screen out tiny particles of allergens.

28.   Contractors, sensing a lucrative new market, have built prototypes of scanning systems that will sense tiny particles of explosives as well as drugs.

29.   Detecting such tiny particles requires a very short wavelength.

30.   EPA also plans new restrictions on the amount of tiny particles of dust released into the air.