MeSH

A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.

A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Elements with partially filled d orbitals. They constitute groups 3-12 of the periodic table of elements.

Year introduced: 2002

Metals with high specific gravity, typically larger than 5. They have complex spectra, form colored salts and double salts, have a low electrode potential, are mainly amphoteric, yield weak bases and weak acids, and are oxidizing or reducing agents (From Grant and Hackh's Chemical Dictionary, 5th ed)

Year introduced: 1997

Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant and Hackh's Chemical Dictionary, 5th ed)

A broad class of substances encompassing all those that do not include carbon and its derivatives as their principal elements. However, carbides, carbonates, cyanides, cyanates, and carbon disulfide are included in this class.

Year introduced: 1998

Substances that comprise all matter. Each element is made up of atoms that are identical in number of electrons and protons and in nuclear charge but may differ in mass or number of neutrons.

Activities which affect organs and systemic functions without regard to a particular disease.

Year introduced: 2004

A broad category of chemical actions and uses that result in the prevention, treatment, cure or diagnosis of disease. Included here are drugs and chemicals that act by altering normal body functions, such as the REPRODUCTIVE CONTROL AGENTS and ANESTHETICS. Effects of chemicals on the environment are also included.

Year introduced: 2004(1999)

A group of pharmacologic activities, effects on living systems and the environment, and modes of employment of drugs and chemicals. They are broken into actions, which describe their effects, and uses, which describe how they are employed.

Year introduced: 1999

Essential dietary elements or organic compounds that are required in only small quantities for normal physiologic processes to occur.

Year introduced: 1996