Consulta: subjectFacets:"Calcite"
Registros recuperados: 5
Data/hora: 09/06/2024 01:32:57

Nuclear anomalies in the buccal cells of calcite factory workers
Provedor de dados: 74
Autores: 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

Avaliação de uma rocha ígnea como corretivo de acidez e disponibilização de nutrientes para as plantas.
Provedor de dados: 14
Autores: ANDRADE, L. R. M. de; MARTINS, E. de S.; MENDES, I. de C.
RESUMO: O objetivo deste trabalho foi avaliar o potencial da rocha fresca carbonatito, proveniente da mina de fosfato localizada em Catalão - GO, como um possível fonte de insumos para a agricultura. O ensaio foi conduzido no campo, com o objetivo de avaliar o potencial de carbonatito como fonte de: (a) P; e, (b) K, para uma pastagem de Brachiaria ruziziensis. Foram realizados três cortes (abril/2000, fevereiro e maio/2001) das plantas e amostragem de solo e do tecido para análises químicas. Os resultados obtidos aos 560 dias depois da aplicação do carbonatito (CBT) demonstram que a maior produção de matéria seca (MS) foi atingida com a aplicação de 200 kg P2O5 / ha ) na forma solúvel. Não houve efeitos significativos do CBT como fonte de P na produção de...
Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E)
Palavras-chave: PVGSOL200; Correcao do solo; Rock.; Acidez do Solo; Calcário; Corretivo; Fósforo; Magnesito; Insumo; Nutriente; Pastagem; Potássio; Rocha; Solo.; Farm inputs; Calcite; Liming; Phosphorus; Nutrients; Pastures; Potassium; Soil pH.; Soil amendments.
Ano: 2002
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/563943

Shell of the Great Scallop Pecten maximus as a high-frequency archive of paleoenvironmental changes - art. no. Q08001
Provedor de dados: 5
Autores: 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

Morphosynthesis: high fidelity inorganic replica of the fibrous network of loofa sponge (Luffa cylindrica)
Provedor de dados: 42
Autores: Mazali,Italo O.; Alves,Oswaldo L.
High fidelity calcium carbonate and hydroxyapatite (bio) inorganic replicas of the fibrous network of the dried fruit of Luffa cylindrica are described, utilizing a facile synthetic route. The loofa sponge is a highly complex macroscopic architectural template, an inexpensive and sustainable resource. In the context of the morphosynthesis, the capability of replication of the loofa sponge opens the possibility of the use of biodiversity in obtaining new materials. We would like to emphasize that the template proposed in this paper, makes possible the preparation of inorganic replicas with a very desirable size, on the centimeter scale. This fact is innovative with respect to inorganic replicas described in the literature, which predominate at the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Morphosynthesis; Biomimetic synthesis; Morphology; Calcite; Hydroxyapatite.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652005000100003

Biomineralization processes of calcite induced by bacteria isolated from marine sediments
Provedor de dados: 58
Autores: 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