| Holliday structure | <molecular biology> A structure which occurs during homologous recombination between homologous chromosomes. While the two chromosomes are side by side, one strand of DNA on each chromosome is broken and then attached to the broken strand of DNA on the other chromosome. The crossover point, which is called the Holliday junction, is able to slide up and down between the two chromosomes, so that a little or a lot of DNA can ultimately be switched between them. (09 Oct 1997) |
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| Holliday, R | <person> See: Holliday junction, Holliday structure. (05 Mar 2000) |
| hollow | 1. A cavity, natural or artificial; an unfilled space within anything; a hole, a cavern; an excavation; as the hollow of the hand or of a tree. 2. A low spot surrounded by elevations; a depressed part of a surface; a concavity; a channel. "Forests grew Upon the barren hollows." (Prior) "I hate the dreadful hollow behind the little wood." (Tennyson) 1. Having an empty space or cavity, natural or artificial, within a solid substance; not solid; excavated in the interior; as, a hollow tree; a hollow sphere. "Hollow with boards shalt thou make it." (Ex. Xxvii. 8) 2. Depressed; concave; gaunt; sunken. "With hollow eye and wrinkled brow." (Shak) 3. Reverberated from a cavity, or resembling such a sound; deep; muffled; as, a hollow roar. 4. Not sincere or faithful; false; deceitful; not sound; as, a hollow heart; a hollow friend. Hollow newel, a pier of stone or brick made behind the lock gates of a canal, and containing a hollow or recess to receive the ends of the gates. Hollow root. <botany> See Moschatel. Hollow square. See Square. Hollow ware, hollow vessels; a trade name for cast-iron kitchen utensils, earthenware, etc. Synonym: Concave, sunken, low, vacant, empty, void, false, faithless, deceitful, treacherous. Origin: OE. Holow, holgh, holf, AS. Holh a hollow, hole. Cf. Hole. Source: Websters Dictionary (01 Mar 1998) |
| hollow back | Accentuation of the lumbar curvature of the spine. (27 Sep 1997) |
| hollow bone | A bone that is hollow or contains many air cells, such as the mastoid process of the temporal bone. Synonym: os pneumaticum, hollow bone. (05 Mar 2000) |
| hollow fibre reactor | A fermentation system in which the cells are separated from the medium using semipermeable membranes arranged in the form of hollow fibres. (14 Nov 1997) |
| hollow wall | A condition of the hoof wall in the toe region of horses, characterised by loss of substance and change in character of the horn, most often as a sequela of mild chronic laminitis. Synonym: dystrophia ungulae, hollow wall. (05 Mar 2000) |
| hollow-hearted | Insincere; deceitful; not sound and true; having a cavity or decayed spot within. Synonym: Faithless, dishonest, false, treacherous. Source: Websters Dictionary (01 Mar 1998) |
| hollow-horned | <zoology> Having permanent horns with a bony core, as cattle. Source: Websters Dictionary (01 Mar 1998) |
| holly | 1. <botany> A tree or shrub of the genus Ilex. The European species (Ilex Aguifolium) is best known, having glossy green leaves, with a spiny, waved edge, and bearing berries that turn red or yellow about Michaelmas. The holly is much used to adorn churches and houses, at Christmas time, and hence is associated with scenes of good will and rejoicing. It is an evergreen tree, and has a finegrained, heavy, white wood. Its bark is used as a febrifuge, and the berries are violently purgative and emetic. The American holly is the Ilex opaca, and is found along the coast of the United States, from Maine southward. 2. <botany> The holm oak. See 1st Holm. <botany> Holly-leaved oak, a species of Eryngium. See Eryngium. Origin: OE holi, holin, AS. Holen, holegn; akin to D. & G. Hulst, OHG. Huls hulis, W. Celyn, Armor. Kelen, Gael. Cuilionn, Ir. Cuileann. Cf. 1st Holm, Hulver. Source: Websters Dictionary (01 Mar 1998) |
| hollyhock | <botany> A species of Althaea (A. Rosea), bearing flowers of various colours. Synonym: rose mallow. Origin: OE. Holihoc; holi holy + hoc mallow, AS. Hoc; cf. W. Hocys mallows, hocys bendigaid hollyhock, lit, blessed mallow. Prob. So named because brought from the Holy Land. See Holy. Source: Websters Dictionary (01 Mar 1998) |
| holm | <botany> A common evergreen oak, of Europe (Quercus Ilex). Synonym: ilex, and holly. Origin: OE, prob. From AS. Holen holly; as the holly is also called holm. See Holly. 1. An islet in a river. 2. Low, flat land. "The soft wind blowing over meadowy holms. <zoology>" (Tennyson) Holm thrush, the missel thrush. Origin: AS. Holm, usually meaning, sea, water; akin to Icel. Holmr, holmr, an island, Dan. Holm, Sw. Holme, G. Holm, and prob. To E. Hill. Cf. Hill. Source: Websters Dictionary (01 Mar 1998) |
| Holmes heart | A variant of double inlet left ventricle where the ventricular-arterial connection is concordant and the right ventricle is rudimentary. Horizontal heart, description of the heart's electrical position; recognised in the electrocardiogram when the QRS in lead aVL resembles that in V6 and QRS in aVF resembles that in V1; also, loosely, when the electrical axis lies between -30 |
| Holmes' stain | <technique> A silver nitrate staining method for nerve fibres. (05 Mar 2000) |
| Holmes, Oliver Wendell | <person> American physician, identified the mode of spread and control of puerperal fever, thus saving innumerable young women's lives. (05 Mar 2000) |