Columbia Encyclopedia

Search results

500 results found

polybrominated biphenyl

(Encyclopedia)polybrominated biphenyl or PBB, any of a group of organic compounds used as a fire retardant. In 1973 several thousand pounds of PBB were accidentally mixed with livestock feed that was later distribu...

fetal tissue implant

(Encyclopedia)fetal tissue implant or fetal cell therapy, implantation of tissue from a fetus into a patient. In experimental procedures, fetal brain tissue has been implanted in the brains of patients with Parkins...

herpes simplex

(Encyclopedia)herpes simplex hûrˈpēz [key], an acute viral infection of the skin characterized by one or more painful, itching blisters filled with clear fluid. It is caused by either of two herpes simplex virus...

koala

(Encyclopedia)koala kōäˈlə [key], arboreal marsupial, or pouched mammal, Phascolarctos cinereus, native to Australia. Although it is sometimes called koala bear, or Australian bear, and is somewhat bearlike in ...

blindness

(Encyclopedia)blindness, partial or complete loss of sight. Blindness may be caused by injury, by lesions of the brain or optic nerve, by disease of the cornea or retina, by pathological changes originating in syst...

diabetes

(Encyclopedia)diabetes or diabetes mellitus məlīˈtəs [key], chronic disorder of glucose (sugar) metabolism caused by inadequate production or use of insulin, a hormone produced in specialized cells (beta cells ...

eczema

(Encyclopedia)eczema ĕkˈsəmə [key], acute or chronic skin disease characterized by redness, itching, serum-filled blisters, crusting, and scaling. Predisposing factors are familial history of allergic disorders...

disinfectant

(Encyclopedia)disinfectant, agent that destroys disease-causing microorganisms and their spores. Disinfectants, or germicides, are sometimes considered to be substances applied to inanimate bodies, whereas antisept...

dry rot

(Encyclopedia)dry rot, fungus disease that attacks both softwood and hardwood timber. Destruction of the cellulose causes discoloration and eventual crumbling of the wood. This frequently results in the collapse of...

chigger

(Encyclopedia)chigger, minute, six-legged, reddish larva of the harvest mite, one of various red bugs widely distributed throughout the world and common in the S United States. Attaching itself by its mouthparts to...