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Articles by Syrian Private University

A Gateway to Metal Resistance: Bacterial Response to Heavy Metal Toxicity in the Biological Environment

Published on: 3rd September, 2018

OCLC Number/Unique Identifier: 7893781761

Heavy metals and metalloids are dangerous because they have the tendency to bioaccumulate in biological organisms over a period of time. However, it is conceived that a number of phytochemical agents as well microorganism can act as heavy metal removing agent both from human beings and the environment surrounding. For instance, microbes are used for the removal of heavy metals from the water bodies including bacteria, fungi, algae and yeast. This review shows that bacteria can play an important role in understanding the uptake and potential removal behaviour of heavy metal ions. The bacteria are chosen based on their resistance to heavy metals (incl. their toxicities) and capacity of adsorbing them. Due to specific resistance transfer factors, cell impermeability is drastically inhibited by several ion (i.e. mercury, cadmium, cobalt, copper, arsenic) forms. Between these elements, free-ion cadmium and copper concentrations in the biological medium provide more accurate determination of metal concentrations that affect the bacteria, than with most of the other existing media. Metal toxicity is usually assessed by using appropriate metal ion chelators and adjusting pH factor. Bacteria and metals in the ecosystem can form synergistic or antagonistic relationships, supplying each other with nutrients or energy sources, or producing toxins to reduce growth and competition for limiting nutritional elements. Thus, this relation may present a more sustainable approach for the restoration of contaminated sources.
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Chromium Isotopes Detection in their Ores with Minimal Errors

Published on: 4th September, 2018

OCLC Number/Unique Identifier: 7877898834

The industrial production and use of chromium have grown considerably during the past five decades. Abundances of the chromium isotopes in terrestrial samples are identical to 0.01%. Among the dominant species of chromium, the trivalent form widely occurs in nature in chromite ores which is extremely immobilized especially in water bodies. Samples were mixtures of separated chromium isotopes and the calibration was made with the same species as those used in the measurements. The method had simplified the conversion of the ores to chromyl fluoride since the element could be readily separated as lead chromate from the leaching of chromite-sodium peroxide fusions. Isotope assay of chromyl fluoride under certain conditions was measured and the measurements of chromium isotopic anomalies ratios and isotope abundance of the chromite ores have been assessed. These provided sufficient quantitative mass spectrometric data, which were analyzed to calculate the abundance and the mean atomic mass of the questioned isotopes. Based on the high mass spectroscopy stability and the correction factors, the results were of good precision (incl. negligible systematic errors normally associated to inter-laboratory discrepancies) and the Cr isotopes availability (52Cr > 53Cr > 50Cr > 54Cr) was in conjunction with other classical tools such as oxygen isotopes. This paper is important for paleoecological, environmental, archeological, forensic, and nuclear researchers.
Cite this ArticleCrossMarkPublonsHarvard Library HOLLISGrowKudosResearchGateBase SearchOAI PMHAcademic MicrosoftScilitSemantic ScholarUniversite de ParisUW LibrariesSJSU King LibrarySJSU King LibraryNUS LibraryMcGillDET KGL BIBLiOTEKJCU DiscoveryUniversidad De LimaWorldCatVU on WorldCat