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| Wei,Shiping; Cui,Hongpeng; Jiang,Zhenglong; Liu,Hao; He,Hao; Fang,Nianqiao. |
| Biomineralization is a known natural phenomenon associated with a wide range of bacterial species. Bacterial-induced calcium carbonate precipitation by marine isolates was investigated in this study. Three genera of ureolytic bacteria, Sporosarcina sp., Bacillus sp. and Brevundimonas sp. were observed to precipitate calcium carbonate minerals. Of these species, Sporosarcina sp. dominated the cultured isolates. B. lentus CP28 generated higher urease activity and facilitated more efficient precipitation of calcium carbonate at 3.24 ± 0.25 × 10−4 mg/cell. X-ray diffraction indicated that the dominant calcium carbonate phase was calcite. Scanning electron microscopy showed that morphologies of the minerals were dominated by cubic, rhombic and polygonal... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calcium carbonate precipitation; Calcite; Marine bacteria; Urease. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822015000200455 |
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| Diler,Songül Budak; Ergene,Serap. |
| The micronucleus (MN) assay on exfoliated buccal cells is a useful and minimally invasive method for monitoring genetic damage in humans. To determine the genotoxic effects of calcite dust that forms during processing, MN assay was carried out in exfoliated buccal cells of 50 (25 smokers and 25 non-smokers) calcite factory workers and 50 (25 smokers and 25 non-smokers) age- and sex-matched control subjects. Frequencies of nuclear abnormalities (NA) other than micronuclei, such as binucleates, karyorrhexis, karyolysis and 'broken eggs', were also evaluated. Micronuclei and the other aforementioned anomalies were analysed by two way analysis of covariance. The linear correlations between the types of micronucleus and nuclear abnormalities were determined by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calcite; Exfoliated buccal cells; Micronucleus (MN); Genotoxicity. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000200028 |
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| Chauvaud, Laurent; Lorrain, Anne; Dunbar, Robert; Paulet, Yves; Thouzeau, Gérard; Jean, Frédéric; Guarini, Jean-marc; Mucciarone, David. |
| We investigate the environmental and biological controls on oxygen isotope ratios in the shells of modern Pecten maximus bivalves collected alive in the Bay of Brest (France). Seasonal delta(18)O profiles, obtained by drilling the daily calcite ridges deposited at the surface of the left valve, were compared with in situ measurements of temperature and salinity. We show that P. maximus delta(18)O values accurately track seasonal variations in bottom water temperature. Shell growth rate has no significant effect on shell delta(18)O values. Our study demonstrates that daily variations in water temperature can be reconstructed within about 0.5 degrees C. Temperatures estimated with the paleotemperature equation established in this study were compared with... |
| Tipo: Text |
Palavras-chave: Pecten Maximus; Brittany; Paleoenvironment; Estimation; Daily varition; Water temperature; Isotope; Calcite; Shell; Ëecten maximus; Paleotempérature; Variation saisonnière; Température eau; Strie croissance; Isotope; Coquille. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-643.pdf |
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