Sentence examples for substances are necessary from inspiring English sources

Therefore, the continuing efforts to search for new antibacterial substances are necessary and urgently needed.

Sugars, especially the disaccharides sucrose and trehalose, are thought to play important roles in cellular desiccation tolerance [ 19], but it is clear that additional substances are necessary for a cell to attain anhydrobiosis [ 20, 21].

These substances are necessary to sterilize the ear and the piercing tools before use.

Therefore extended exposure to the test substances is necessary to evaluate pharmacologic/toxicologic consequences on embryonic development.

Other researchers believe that the use of activating substances is necessary to stimulate the massive release of growth factors in the foci of the lesion and thus increasing the healing process of the affected tissue [ 32].

A minimum tonnage of the manufactured or imported substance is necessary to trigger registration (1 t/a).

Aquinas would no doubt say that such observation of the immediate functioning of a simple substance is necessary in order to acquire a concept of its substantial nature, and so its real definition.

Substance is necessary and absolute, accidents are relative and contingent.

But EPA's test, conducted on just two kinds of sea animals -- one species of shrimp, and one species of small fish -- only tested to see how much of a substance was necessary to kill them.

Vitamin, any of several organic substances that are necessary in small quantities for normal health and growth in higher forms of animal life.

In summary, for the legal implementation of such an approach, clear criteria to decide if two nanomaterials of the same chemical composition are different substances in the meaning of REACH are necessary.