(n.) A pearly substance which lines the interior of many shells, and is most perfect in the mother-of-pearl. [Written also nacker and naker.] See Pearl, and Mother-of-pearl.
Example Sentences:
(1) When nacreous shell produced by the marine oyster Pinctada maxima, used as a biomaterial in oral surgery, is implanted in human bone, new bone formation occurs, resulting in a tight welding of the bone to the nacre [16].
(2) Dilute suspensions of normal erythrocytes exhibit a pearl-like sheen (nacre) when subjected to flow.
(3) Nacre implanted in vivo in bone is osteogenic suggesting that it may possess factor(s) which stimulate bone formation.
(4) These observations are discussed namely in relation to the problem of structural identification of the EDTA soluble fraction of the nacre conchiolin.
(5) To test this hypothesis, we have evaluated the effect of the simultaneous presence of bone and nacre on human osteoblasts in vitro.
(6) In other areas (along the main course of the mantle), transient adhesions between the outer mantle epithelial cells and the nacre appear to temporally further compartmentalize the extrapallial fluid possibly as a prerequisite for the initial crystallization phenomenon.
(7) Induction of mineralization appeared preferentially in bundles of osteoblasts surrounding the nacre chips.
(8) Nacre chips (1 mm3) were placed at approximately 1 mm distance from a similarly sized bone chip on a layer of first passage human osteoblasts.
(9) The five tissues, extracellularly mineralizing algae, radial and granular foraminifera, mammalian bone, mammalian enamel, and mollusk shell nacre, probably span the entire spectrum.
(10) The degree of nacre can be measured by comparing the intensity of scattered red light at an angle of 45 degrees for the flowing system to that when the effect has disappeared.
(11) The results demonstrated that nacre has strong osteogenic effects on human osteoblasts when placed in proximity to bone in vitro.
(12) These findings are consistent with the possibility that nacre adjacent to bone can locally stimulate osteogenic activity.
(13) These results demonstrate that a complete sequence of bone formation is reproduced when human osteoblasts are cultured in the presence of nacre.
(14) In addition, under the conditions of culture used, nacre can also promote the formation by osteoblasts of a structure with characteristics similar to nacre (e.g., lamellar organic matrix mineralized with aragonite, as demonstrated by Laser Raman Spectroscopy).
(15) Osteoblasts proliferated and were clearly attracted by nacre chips to which they attached.
(16) A woman exposed to the dust of sea-snail shells during the manufacture of nacre buttons had clinical and immunological features typical of hypersensitivity pneumonitis; however, transbronchial lung biopsy showed alveolar-septal amyloidosis.
(17) Nacre chips were placed on a layer of first passage human osteoblasts.
(18) The present study was undertaken to test the hypothesis that nacre can induce mineralization by human osteoblasts in vitro.
Nacreous
Definition:
(a.) Consisting of, or resembling, nacre; pearly.
Example Sentences:
(1) When nacreous shell produced by the marine oyster Pinctada maxima, used as a biomaterial in oral surgery, is implanted in human bone, new bone formation occurs, resulting in a tight welding of the bone to the nacre [16].
(2) Etching with the glutaraldehyde-acetic acid solution reveals that the nacreous tablets in Mytilus, Nucula, and Unio are composed of four crystal individuals which occur in two structurally different pairs and which are probably cyclically twinned.
(3) The crystalline phases at the first few lamellae were mostly imperfect while the whole nacreous layer acquitted itself into a highly oriented biomineralized aragonite.
(4) From these morphological observations, a regulatory role for the various periostracal layers in mineral trapping, nucleation, and the subsequent formation of the prismatic and nacreous layers of the shell can be postulated.
(5) In all three genera, the nucleation of new nacreous tablets invariably takes place on the top surface of the less-soluble crystal individuals.
(6) Transmission electron microscope studies of the cellular nucleation sites of a biomineralized calcium carbonate(aragonite) in the lamellar nacreous layer of the bivalvia Cristaria plicata (Leach) shell showed that the low density calcium particles were confined within some large vesicles of the bivalve mantle cells on which the crystalline aragonite phases were deposited.
(7) The stack-like growth of the nacreous tablets in the marginal region of the shell in Nucula is probably related to the exceptionally large-sized, less-soluble crystal individuals in the nacreous tablets of this region.
(8) DA is half-moonish and white-nacreous in rodents; its upper surface presents a longitudinal crest.
(9) Larval Schistosoma mansoni have been shown to induce morphological changes to the internal calcium reserves (in particular the calcareous inclusions in Type A calcium cells and to the inner, nacreous layer of the shell) of Biomphalaria glabrata within 48 h of miracidial penetration.
(10) Upon cessation of flow, the nacreous effect decays in 2-3 min, corresponding to the time required for the discs to achieve random orientations by rotatory Brownian motion.
(11) The reaction product was conspicuous in the cell walls and tended to be concentrated in the middle lamella and in the nacreous wall layer of the differentiating sieve elements.