superhyperfine SeeELECTRON PARAMAGNETIC RESO-
NANCE SPECTROSCOPY.
superoxide dismutases (SOD) ENZYMES that cat-
alyze the DISMUTATIONreaction of superoxide anion to
dihydrogen peroxide and dioxygen. The enzymes have
ACTIVE SITEs containing either copper and zinc (Cu/Zn-
superoxide dismutase), iron (Fe-superoxide dismutase),
or manganese (Mn-superoxide dismutase).
supersaturated solution One that contains a higher-
than-saturation concentration of solute. It is an unsta-
ble system, and excess solute will come out of solution
under the proper nucleation conditions.
suprafacial SeeANTARAFACIAL.
supramolecular chemistry This is defined as the
chemistry of molecular assemblies and of the inter-
molecular bond as “chemistry beyond the molecule,”
bearing on the organized entities of higher complexity
that result from the association of two or more chemi-
cal species held together by intermolecular forces.
Thus, supramolecular chemistry may be considered to
represent a generalized COORDINATION chemistry
extending beyond the coordination of TRANSITION ELE-
MENTs by organic and inorganic LIGANDs to the bond-
ing of all kinds of SUBSTRATEs: cationic, anionic, and
neutral species of either inorganic, organic, or biologi-
cal nature.
supramolecule A system of two or more MOLECU-
LAR ENTITIESheld together and organized by means of
intermolecular (noncovalent) binding interactions.
surface tension The cohesive forces between liquid
molecules. Surface tension is typically measured in
dynes/cm, the force in dynes required to break a film of
length 1 cm. Water at 20°C has a surface tension of
72.8 dynes/cm. SURFACTANTs act to reduce the surface
tension of a liquid.
surfactant Any material that lowers the SURFACE
TENSIONof a liquid, e.g., soap, dish detergent.suspension Particles dispersed or undissolved in a
fluid or solid.sustainable A process that can continue indefinitely
without overusing resources and causing damage to the
environment.sustainable agriculture Agricultural techniques and
systems that, while economically viable to meet the need
to provide safe and nutritious foods, utilize nonenviron-
mentally destructive methods such as the use of organic
fertilizers, biological control of pests instead of pesti-
cides, and minimal use of nonrenewable fuel.sustainable development Development and eco-
nomic growth that meets the requirements of the pres-
ent generation without compromising the ability of
future generations to meet their needs; a strategy seek-
ing a balance between development and conservation
of natural resources.Sutherland, Earl W., Jr.(1915–1974) American
Pharmacologist Earl Sutherland was born on Novem-
ber 19, 1915, in Burlingame, Kansas. He received a
B.S. from Washburn College in 1937 and an M.D.
from the Washington University in St. Louis School of
Medicine in 1942.
He joined the faculty of Washington University and
in 1953 became director of the department of medicine
at Case Western Reserve University in Cleveland, Ohio.
Here he discovered cyclic AMP (adenosine monophos-
phate) in 1956.
In 1963 he became professor of physiology at Van-
derbilt University in Nashville, Tennessee. He was
awarded the Nobel Prize for physiology or medicine in
1971 for isolation of cyclic adenosine monophosphate
(cyclic AMP) and for demonstrating its involvement in
numerous animal metabolic processes. From 1973 until
his death he was a member of the faculty of the Univer-
sity of Miami Medical School.260 superhyperfine