Columbia Encyclopedia

(Encyclopedia) tourniquet to͝orˈnĭkĕt, –kā, tûrˈ– [key], compression device used to cut off the flow of blood to a part of the body, most often an arm or leg. It may be a special surgical instrument, a ru...

(Encyclopedia) valve, device for controlling the flow of fluids (liquids and gases). Valves vary in construction and size depending upon their function. Some are classified according to their method of operation or ...

(Encyclopedia) sepal, a modified leaf, part of the outermost of the four groups of flower parts. The sepals of a flower are collectively called the calyx and act as a protective covering of the inner flower parts in...

(Encyclopedia) infertility, inability to conceive or carry a child to delivery. The term is usually limited to situations where the couple has had intercourse regularly for one year without using birth control. The ...

(Encyclopedia) notochord nōˈtəkôrdˌ [key], in biology, supporting rod running most of the length of animals of the phylum Chordata and present at varying times in the life cycle. Composed of large cells packed ...

(Encyclopedia) cellophane, thin, transparent sheet or tube of regenerated cellulose. Cellophane is used in packaging and as a membrane for dialysis. It is sometimes dyed and can be moisture-proofed by a thin coating...

(Encyclopedia) Hooker, John Lee, 1917–2001, American blues singer and guitarist, b. near Clarksdale, Miss. From a cotton-sharecropping family, he learned the blues from his stepfather and various visiting Delta bl...

(Encyclopedia) Forssmann, Werner vĕrˈnər fôrsˈmän [key], 1904–79, German physician and physiologist, M.D. Univ. of Berlin (1929). In the late 1920s, he developed the technique of cardiac catheterization, whe...

(Encyclopedia) Store Bælt Bridge stôˈrə bĕlt [key], link comprising two bridges and a tunnel, S Denmark, across the Store Bælt strait (see Store Bælt and Lille Bælt) between Sjælland and Fyn islands. The en...

(Encyclopedia) Mullis, Kary Banks, 1944–2019, American biochemist, b. Lenoir, N.C., Ph.D. Univ. of California, Berkeley, 1972. Mullis was a researcher with Cetus Corp., Emeryville, Calif., from 1979 to 1986 and wi...