| yellow wax | A yellowish, solid, brittle substance prepared from the honeycomb of the bee, Apis mellifera; the chief constituent is myricin (myricyl palmitate); others are cerotic acid (cerin), melissic acid, heptacosane, and hentriacontane; used in the preparation of ointments, cerates, plasters, and suppositories. (05 Mar 2000) |
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| yellow yolk | The chief constituent of the yolk in a bird's egg; it consists of relatively coarse particles of stored food materials and is laid down in concentric zones with interposed thin layers of white yolk. (05 Mar 2000) |
| Leipzig yellow | A fine yellow powder used in paints and dyes. Synonym: lead chromate, Leipzig yellow, lemon yellow, Paris yellow. (05 Mar 2000) |
| lemon yellow | A fine yellow powder used in paints and dyes. Synonym: lead chromate, Leipzig yellow, lemon yellow, Paris yellow. (05 Mar 2000) |
| ABO blood group | <haematology> The major human blood type system which describes the oligosaccharide glycoprotein antigens found on the surface of human blood cells. According to the type of antigen present, a person may be assigned a blood type of A, B, AB or O. A second type of antigen, the Rh factor, renders a positive or negative blood type. The ABO blood group system is important because it determines who can donate blood to or accept blood from whom. Type A or AB blood will cause an immune reaction in people with type B blood and type B and AB blood will cause a reaction in people with type A blood. Conversely, type O blood has no A or B antigens, so people with type O blood are universal donors. And since AB blood already produces both antigens, people who are type AB can accept any of the other blood types without suffering an immune reaction. (04 Jul 1999) |
| actinobacteria group | A group of gram-positive, heterogeneous bacteria. This group encompasses a range of morphologically, physiologically, and chemically different organisms and includes bacteria that form cocci, short rods, irregular rods, and mycelia that fragment. (12 Dec 1998) |
| alkyl group | <chemistry> A funtional group on an organic molecule which is derived from an alkane which has lost a hydrogen atom. (13 Nov 1997) |
| aluminum group | Aluminum, boron, gallium, indium, and thallium. (05 Mar 2000) |
| amino group | <biochemistry> An -NH2 group. Organic compounds which have this group are called amines. (09 Oct 1997) |
| anterior group of axillary lymph nodes | Lymph nodes located along the lateral thoracic vein; they receive the drainage of the pectoral region, including most of the drainage of the breast. Synonym: nodi lymphatici axillaris pectorales, anterior group of axillary lymph nodes. (05 Mar 2000) |
| apical group of axillary lymph nodes | The group of lymph node's located at the apex of the axillary fossa that receive lymphatic drainage from other groups of axillary node's and then drain in turn into the subclavian lymphatic trunk. Synonym: nodi lymphatici axillares apicales. (05 Mar 2000) |
| Bethesda-Ballerup Group | A group of citrate-utilizing, slow lactose-fermenting bacteria (family Enterobacteriaceae) which share a similar series of antigens with the lactose-fermenting citrobacters; these organisms are now included in the genus Citrobacter without a distinction between prompt and slow lactose fermentation. (05 Mar 2000) |
| blood group | <haematology> An inherited feature on the surface of the red blood cell. A series of related blood groups make up a blood group system such as the ABO system or the Rh system. Erythrocytic allotypes (or phenotypes) defined by one or more cellular antigenic structural groupings under the control of allelic genes. Blood groups, especially for man, are identified by agglutinins supported by specific human or animal antisera and by lectins extracted from certain plants. See: blood group antigen. (25 Jun 1999) |
| blood group antigen | <haematology, immunology> The set of cell surface antigens found chiefly, but not solely, on blood cells. More than fifteen different blood group systems are recognised in humans. There may be naturally occurring antibodies without immunisation, especially in the case of the ABO system and matching blood groups is important for safe transfusion. In most cases the antigenic determinant resides in the carbohydrate chains of membrane glycoproteins or glycolipids. See: Rhesus, Duffy, Kell, Lewis and MN. (25 Jun 1999) |
| blood group incompatibility | A mismatch between donor and recipient blood. Antibodies present in the recipient's serum are directed against antigens in the donor product. Such a mismatch may result in a transfusion reaction in which, for example, donor blood is haemolyzed. (12 Dec 1998) |