1.   This means that man-made substances are not produced at a faster pace than they can be broken down by nature.

2.   Cases of pulmonary haemorrhage have occurred in workers in factories producing these substances.

3.   Although full-term infants are able to produce the substance themselves, premature babies cannot.

4.   And Soejarto discovered a second species that produced a substance similar to Calanolide A.

5.   Before this development, the substance could be produced only from petrochemicals.

6.   A lack of vitamin A also leads to impaired production of cytokines, substances produced by cells that are important in immune reactions.

7.   For example, the brain produces amphetaminelike substances that have an effect on heartbeat and blood flow.

8.   Harmless bacteria coat the skin producing substances that prevent harmful germs from invading.

9.   No one knows why tumors produce substances that inhibit angiogenesis as well as others that promote it.

10.   Officials said the substance had been produced in such a fine form that it was easily spread through the air.