(n.) A mollusk having a shell consisting of two lateral plates or valves joined together by an elastic ligament at the hinge, which is usually strengthened by prominences called teeth. The shell is closed by the contraction of two transverse muscles attached to the inner surface, as in the clam, -- or by one, as in the oyster. See Mollusca.
(n.) A pericarp in which the seed case opens or splits into two parts or valves.
(a.) Having two shells or valves which open and shut, as the oyster and certain seed vessels.
Example Sentences:
(1) Start your exploring at Bearreraig Bay, where, if you are lucky, you may find belemnites, ammonites and bivalves.
(2) To compare biochemical differences between bivalves with and without endosymbiotic chemoautotrophic bacteria, specimens of Solemya velum, a bivalve species known to contain bacterial endosymbionts, and the symbiont-free soft-shelled clam Mya arenaria, were collected from the same subtidal reducing sediments during October and November 1988.
(3) We have demonstrated that M. edulis, a marine bivalve mollusc, reacts to the vertebrate monokines interleukin-1, -6 and TNF.
(4) Total neutral and acidic glycosphingolipids were prepared from whole tissues of the sea-water bivalve, Meretrix lusoria, and the former preparation was further fractionated into subgroups by silicic acid column chromatography.
(5) The development of microparticulate food particles for marine suspension-feeders is discussed with respect to the difficulties of nutrient delivery in the aquatic environment and to feeding and digestion in crustacea and bivalve molluscs.
(6) Attempts to introduce infectious or foreign material into oysters and other bivalve mollusks usually involve force or trauma because of immediate, prolonged adduction of the tightly closing valves.
(7) This observation, together with the finding that the oyster shell has a strong affinity for virus, suggests that surface properties, rather than size, are the principal factors governing the accumulation of viruses by filter-feeding marine bivalves.
(8) Chromatin organization in the sperm of the bivalve mollusks results from the interaction between a discrete number of protamine-like proteins (PL) and DNA.
(9) There was the doll's house-sized two-pronged fork, and the bivalves themselves, pale and ivory against the silvered shell.
(10) Infectious pancreatic necrosis virus of fish, infectious bursal disease virus of chickens, Tellina virus and oyster virus of bivalve molluscs, and drosophila X virus of Drosophila melanogaster are naked icosahedral viruses with an electron microscopic diameter of 58 to 60 nm.
(11) The control measures consisted of the prohibition of the harvest and sale of all bivalve mollusks as well as a public warning to avoid the consumption of such shellfish.
(12) The ultrastructural morphology of peripheral neurons and associated structures in the bivalve mollusc.
(13) In 6 male baboons, the left kidney was bivalved and repaired using a fibrin adhesive (group A) or conventional suturing (group B).
(14) There are various types of photoproteins: the photoproteins of coelenterates, ctenophores and radiolarians require Ca2+ to trigger their luminescence; the photoproteins of the bivalve Pholas and of the scale worm appear to involve superoxide radicals and O2 in their light-emitting reactions; the photoprotein of euphausiid shrimps emits light only in the presence of a special fluorescent compound; the photoprotein of the millipede Luminodesmus, the only known example of terrestrial origin, requires ATP and Mg2+ to emit light.
(15) Most progress is being made in relation to lethal blood mutant neoplasms in Drosophila, leukaemias of farmed salmonids among the fishes, and among shellfish, the hemic sarcomas of bivalves.
(16) Distribution of MlOse4Cer and MlXOse5Cer in various bivalve and snail glycolipid extracts were screened in thin-layer immunobinding assays by using this purified specific antibody.
(17) In the haemolymph of the Tridacnid bivalve clams anti-galactans occur which do not have only glycosubstance precipitating and cell agglutinating properties, but also show mitogenic activity with respect to the blast transformation of human peripheral lymphocytes.
(18) The pericardial glands of three bivalve molluscs are composed of convoluted epithelium that appears as pouches on the auricles of Mytilus and as tubules in the connective tissue at the anterior-lateral sides of the pericardial cavity of Mercenaria and Anodonta.
(19) Four biotypes and five antigenic types of bacteria, pathogenic for the larvae of five species of bivalve mollusks, were isolated and described in some detail.
(20) Laboratory toxicity tests performed on the bivalve Cerastoderma edule submitted to sublethal concentrations of paper mill effluent revealed significant decreases of adenylate energy charge (AEC), and changes in the total adenylate pool were observed in a 24-hr period even for the lowest concentration of pollutant tested.
Umbo
Definition:
(n.) The boss of a shield, at or near the middle, and usually projecting, sometimes in a sharp spike.
(n.) A boss, or rounded elevation, or a corresponding depression, in a palate, disk, or membrane; as, the umbo in the integument of the larvae of echinoderms or in the tympanic membrane of the ear.
(n.) One of the lateral prominence just above the hinge of a bivalve shell.
Example Sentences:
(1) The position, displacement and phase angle of the rotation axis of the ossicles was calculated based on the displacement and phase angle of the umbo, malleus head and lenticular process.
(2) The bending will also affect the displacements transmitted to the ossicular load, and introduce significant errors into estimates of such displacements based on measurements of umbo displacement even at frequencies as low as a few kHz.
(3) The umbo region may represent the center of superficially radial dispersion.
(4) The epithelial migration center was found at the region of umbo, manubrium, and the short process of the malleus.
(5) It is demonstrated that the rotation angels can not account for the measured movement of the umbo, which leads to the conclusion that for static high pressure levels the classical hypothesis of rotation around a fixed axis has to be abandoned.
(6) There is a small area we have termed the "slow zone", located anterior and inferior to the umbo, that has comparatively fewer patches and where ink dots can remain static for several weeks.
(7) This attachment is most intimate at the level of the umbo and becomes progressively more tenuous as the short process is approached.
(8) It is shown further that a linear relationship between umbo displacement and volume displacement exists.
(9) The acoustically estimated "drum location" generally lay between the optically determined vertical planes containing the TOD and the umbo.
(10) The displacement of the umbo is compared to other work.
(11) All of the modifications (except the perforation) had a minimal effect on umbo displacement; this seems to imply that the pars flaccida has a minor acoustic role in human beings.
(12) Due to the gliding movement in the malleus-incus joint, this motion changes at the umbo into outward rotation, counteracting the tensor tympani muscle.
(13) When the motion is rotational the position of the axis of rotation shifts with frequency, the shifts are so large that the axis can lie near the umbo so that amplitudes at the processus lateralis are larger than at the umbo.
(14) The umbo moved piston-like at 0.1-0.8 kHz and 2.6-4.5 kHz but in an ellipse at 1.0-2.4 kHz.
(15) The vibration amplitude and phase angle of the umbo, malleus head, lenticular process and stapes head were measured at 19 frequencies between 0.1 kHz and 4.5 kHz.
(16) The malleus head showed elliptical movement with its long axis anteriorly tilted around 45 degrees from the direction of the umbo vibration at 0.1 kHz.
(17) As a result of the bending, the frequency response at the umbo at high frequencies displays much higher amplitudes and larger phase lags than when the manubrium is rigid.
(18) The effects of aditus blockage, decrease of tympanic cavity volume, and resection of the tensor tympani muscle on umbo displacement were studied in human temporal bones using a new non-contacting video measuring system.
(19) The umbo, lenticular process and stapes head vibrated parallel at lower frequencies.
(20) The three-dimensional movements of the umbo, the proc.