Consulta: subjectFacets:"Silver"
Registros recuperados: 10
Data/hora: 07/06/2024 09:40:53

Differential bioaccumulation behaviour of Ag and Cd during the early development of the cuttlefish Sepia officinalis
Provedor de dados: 5
Autores: Lacoue Labarthe, T; Warnau, A; Oberhansli, F; Teyssie, J; Koueta, Noussithe; Bustamante, Paco.
Cuttlefish eggs were exposed to background concentrations of dissolved Ag and Cd, using the radiotracers Ag-110m and Cd-109. At different time of the embryonic development (50 days), some eggs were placed in non-contaminating conditions. During the experiment, the uptake and depuration kinetics, and distribution of these metals among the egg compartments (i.e. eggshell, vitellus, peri-vitelline fluid and embryo) were assessed. In parallel, experiments were conducted with sub-lethal concentrations of stable Ag and Cd (2 and 1 mu g l(-1), respectively) to compare the metal behaviour at higher concentrations. From the spawning date up to I month of development, both metals were taken up efficiently by the eggs, reaching load/concentration ratio (LCR) of 1059...
Tipo: Text
Palavras-chave: Cephalopod; Permeability; Eggshell; Embryo; Biokinetics; Silver; Cadmium.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-3882.pdf

Long-term records of cadmium and silver contamination in sediments and oysters from the Gironde fluvial-estuarine continuum - Evidence of changing silver sources
Provedor de dados: 5
Autores: Lanceleur, Laurent; Schaefer, Joerg; Chiffoleau, Jean-francois; Blanc, Gerard; Auger, Dominique; Renault, Sophie; Baudrimont, Magalie; Audry, Stephane.
The Gironde fluvial estuarine system is impacted by historic metal pollution (e.g. Cd, Zn, Hg) and oysters (Crassostrea gigas) from the estuary mouth have shown extremely high Cd concentrations for decades. Based on recent work (Chiffoleau et al., 2005) revealing anomalously high Ag concentrations (up to 65 mg kg(-1); dry weight) in Gironde oysters, we compared long-term (similar to 1955-2001) records of Ag and Cd concentrations in reservoir sediment with the respective concentrations in oysters collected between 1979 and 2010 to identify the origin and historical trend of the recently discovered Ag anomaly. Sediment cores from two reservoirs upstream and downstream from the main metal pollution source provided information on (i) geochemical background...
Tipo: Text
Palavras-chave: Silver; Cadmium; Estuary; Oyster; Biomonitoring.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00060/17109/15071.pdf

L'argent (Ag, nanoAg) comme contaminant émergeant dans l'Estuaire de la Gironde : évaluations scientifiques et gouvernance des risques
Provedor de dados: 5
Autores: Salles, Denis; Roumezi, Alexis; Lanceleur, Laurent; Schaefer, Jorg; Petit, Jerome; Blanc, Gerard; Coynel, Alexandra; Chiffoleau, Jean-francois; Auger, Dominique.
This article presents the results of multidisciplinary research (geochemistry, sociology) into the increasing concentrations of silver (Ag and nanoAg) in the environment and their potential impact on aquatic environments. We investigate simultaneously the risk of contamination of these environments by silver and the process of the social and political construction of this risk by water managers, health authorities, agencies and committees responsible for expert evaluations, environmental associations, and potential users of silver or nano-silver. Four updated models of risk construction allow us to understand the logic of arguments mobilized at this stage of the emerging risk. This interdisciplinary cooperation opens up possibilities for dealing with some...
Tipo: Text
Palavras-chave: Environment; Estuaries; Geochemistry; Interdisciplinary communication; Nanotechnology; Risk assessment; Risk management; Silver; Sociology; Water pollutants.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00156/26736/24939.pdf

Distribution of silver in mussels and oysters along the French coasts: Data from the national monitoring program
Provedor de dados: 5
Autores: Chiffoleau, Jean-francois; Auger, Dominique; Roux, Nathalie; Rozuel, Emmanuelle; Santini, Anne.
Distribution and behavior of many trace elements in the aquatic environment has been well characterized, but little is known about silver (Ag) concentrations in coastal waters, even though this element ranks among the most toxic to marine invertebrates (Calabrese et al., 1977 ; Fisher and Hook, 1997 ; Webb and Wood, 1998). Studies conducted by Flegal et al. (1995), River-Duarte et al. (1999), and Ndung'u et al. (2001), provided the first valuable data on Ag distribution in the oceanic environment, indicating that this element is found in very low concentrations in the dissolved phase. However, although silver concentrations in coastal waters do not reach the nanomolar range (Smith and Flegal, 1993 ; Squire et al., 2002), formation of a stable chloro...
Tipo: Text
Palavras-chave: Mollusks; Coastal water; Silver; Monitoring.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-2553.pdf

The distribution of silver specimens from the Kongsberg Silver Mines, Norway, 17th and 18th centuries
Provedor de dados: 16
Autores: Berg, B.I.; Nordrum, F.S.
Specimens of native silver from the Kongsberg mines in Norway are world famous and have been distributed through sales and gifts during the whole period of mining from 1623 to 1958. Names of customers, the number of sold specimens and their silver content are documented in accounts which are preserved back to the 1620s. The Danish-Norwegian kings received the largest amounts of silver specimens.
Tipo: Article / Letter to the editor
Palavras-chave: Silver; Specimens sales; Collections; History; Norway; 38.52.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/215334

A metallic impregnation technique adapted to study the honeybee Apis mellifera L. brain
Provedor de dados: 82
Autores: Calábria,Luciana K; Teixeira,Renata R; Moraes,Viviane R A; Santos,Ana Alice D; Espindola,Foued S.
In order to visualize the distribution pattern of the neuronal bodies and neurofibrils in the honeybee brain, we adapted a metallic impregnation technique first described for vertebrate nervous system by Ramón y Cajal. The honeybee brain constitution plays a key role in the development of learning and memory capacities. The general characteristics observed in the honeybee brain, stained by metallic impregnation, revealed its anatomical and morphological constitution in agreement with studies of other insect brains using different techniques. Metallic impregnation evidenced the optic lobe neuropils, the ocelli fiber cells, the neuron extensions of the calyces, and the axon bundles that involve the antennal glomeruli, as well as the neuron extensions in the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Neurofibril; Neuron; Invertebrate; Silver.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2010000500008

Acute silver toxicity to Cnesterodon decemmaculatus (Pisces: Poeciliidae) in a river with extreme water-quality characteristics
Provedor de dados: 40
Autores: Casares,María Victoria; de Cabo,Laura I; Seoane,Rafael; Natale,Oscar.
Abstract. A 96 h acute silver toxicity test was performed in order to determine silver toxicity (LC50) to a local fish species (Cnesterodon decemmaculatus) in a river with extreme water-quality characteristics (Pilcomayo River, South America) and evaluate a cross-fish-species extrapolation of the Biotic Ligand Model. The dissolved silver concentrations tested were 0.095, 0.148, 0.175 and 0.285 mg Ag L&amp;#8722;1. The 96 h Ag LC50 calculated for C. decemmaculatus was 0.14 mg L&amp;#8722;1 (0.18 - 0.10) and the value predicted by BLM for Pimephales promelas was 0.051 mg Ag L&amp;#8722;1. Test water elevated hardness may have exerted some protective effect. High mean water pH may have exerted a major protective effect by reducing silver free ion form and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Silver; Cnesterodon decemmaculatus; Biotic Ligand Model; Extrapolation.
Ano: 2013
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-37432013000200004

The promoting effect of cesium on structure and morphology of silver catalysts
Provedor de dados: 42
Autores: Carvalho,Marta C. N. A.; Perez,Carlos A.; Simão,Renata A.; Passos,Fabio B.; Schmal,Martin.
Silver supported catalysts on alpha-alumina were prepared and characterized by Brunauer-Emmet-Teller equations, scanning electronic microscopy, X-ray diffraction and atomic force microscopy techniques. Results show that these are powerful techniques for the determination of texture, morphology and surface properties. It has been shown that the addition of Cs in the Ag/Al2O3 catalyst increased the dispersion of silver with the formation of small silver particles over a thin silver film already formed over the alumina support. It is important to stress that atomic force microscopy measurements are significant to observe the film and the dispersion of Ag and, on the contrary, X-ray photoelectronic spectroscopy did not, however, it allows to the conclusion...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Silver; Cesium; Catalyst; AFM; XPS.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652004000100003

Evaluation of the Toxicity of Silver/Silica and Titanium Dioxide Particles in Mammalian Cells
Provedor de dados: 52
Autores: Pittol,Michele; Tomacheski,Daiane; Simões,Douglas Naue; Ribeiro,Vanda Ferreira; Santana,Ruth Marlene Campomanes.
ABSTRACT The increasing concern over the spread of diseases has lead to a high consumption of antimicrobial additives in the medical and industrial fields. Since these particles can lixiviate from loaded materials, the contact between this additive and mammalian cells can occur during manufacture, use and disposal of the products. Silver on fumed silica (AgNP_SiO2) and titanium dioxide (TiO2) can be used as antimicrobial additives that are applied in polymeric formulation. While these additives can inhibit bacteria, fungus and virus proliferation; they may also be harmful to humans. Standard toxicological studies were undertaken using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide), CBPI (cytokinesis-block proliferation index) and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Titanium dioxide; Silver; Silica; Toxicology; Mammalian cell.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132018000100318

Uptake of free and complexed silver ions by different strains of Rhodotorula mucilaginosa
Provedor de dados: 58
Autores: Gomes,Newton C.M.; Rosa,Carlos A.; Pimentel,Patrícia F.; Mendonça-Hagler,Leda C.S.
Five strains of Rhodotorula mucilaginosa were tested for the ability to accumulate free and complexed silver ions by metabolism-dependent and -independent processes. The ability to take up Ag+ was observed in both live and dead biomass, whereas silver dicyanide [Ag (CN)2-] uptake was strictly glucose dependent. In contrast to Ag (CN)2-, glucose addition inhibited by 16 to 25% the Ag+ uptake rate of living UFMG - Y02, Y27, and Y35 cells, while strains CBS 316 and UFMG-Y01 showed an improved uptake rate of about 115% and 13%, respectively. The Langmuir sorption model was used to evaluate the silver sorption capability of the R. mucilaginosa strains. The calculated q max value suggested that R. mucilaginosa strains UFMG-Y27 had the highest loading capacity....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bioaccumulation; Biosorption; Rhodotorula mucilaginosa; Silver.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822002000100013