Search results for "MAGNESIUM"
showing 10 items of 490 documents
Direct determination of calcium, magnesium, sodium and potassium in water by flow injection flame atomic spectroscopy, using a dilution chamber
1989
A simple procedure to carry out the direct analysis of calcium, magnesium, sodium and potassium in water by flow injection analysis (FIA) using flame atomic absorption spectroscopy (AAS) or flame photometry (FP) has been developed, using a well stirred dilution chamber to extend the calibration range, and both a double injector and the merging zone technique to add a lanthanum solution to samples and standards. The results obtained in the analysis of real samples agree with those found by a batch flame atomic procedure. The use of the dilution chamber makes it possible to carry out the calibration using the dilution profile of a single concentrate standard for each element, and an empirical…
[The in vitro effect of the addition of ion exchange resins on the bioavailability of electrolytes in artificial enteral feeding formulas].
2008
Objective: To determine in vitro free ion concentration in 3 standard artificial enteral feeding formulas following the addition of ion exchange resins. Method: Three standard types of AEF were chosen: Osmolite HN®, Nutrison Standard®, and Isosource Standard®. The ion exchange resins used were: sodium polystyrene sulfonate and calcium polystyrene sulfonate. In a beaker were mixed 100 mL of AEF with 1.5 g or 3 g of ion exchange resins for 48 hours at 37oC. Subsequently, the samples were precipitated and the supernatant obtained was used for determining the concentrations of calcium, magnesium, sodium, and potassium ions. Results: The addition of sodium polystyrene sulfonate to different type…
A numerical approach for the modelling of forming limits in hot incremental forming of AZ31 magnesium alloy
2021
AbstractMagnesium alloys, because of their good specific material strength, can be considered attractive by different industry fields, as the aerospace and the automotive one. However, their use is limited by the poor formability at room temperature. In this research, a numerical approach is proposed in order to determine an analytical expression of material formability in hot incremental forming processes. The numerical model was developed using the commercial software ABAQUS/Explicit. The Johnson-Cook material model was used, and the model was validated through experimental measurements carried out using the ARAMIS system. Different geometries were considered with temperature varying in a…
Electroactive polymeric material with condensed structure on the basis of magnesium(II) polyporphine
2011
International audience; Previous publication of the authors presented evidences that electroch emical oxidation of Mg(II) porphine (fully unsubstituted porphyrin, MgP) in acetonitrile (AN) at a very low potential leads to deposition of films at electrode surface corresponding to typical electroactive polymers, with their reversible transition betwee n the electronconducting and insulating states depending on the electrode potential/oxidation level ("film of type I"). It is demonstrated in the actual publication that these films in contact with a monomer-free solution are subject to an irreversible transformation to quite a different material ("film of type II") under the influence of a high…
Basaltic Rocks Analyzed by the Spirit Rover in Gusev Crater
2004
The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and MiniâThermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain â¤25% megacrysts. Chemical analyses of rocks by the Alpha Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. MoÌssbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. The…
Mineralogy at Gusev Crater from the Mössbauer spectrometer on the Spirit Rover.
2004
Mössbauer spectra measured on Mars by the Spirit rover during the primary mission are characterized by two ferrous iron doublets (olivine and probably pyroxene) and a ferric iron doublet (tentatively associated to nanophase ferric iron oxide). Two sextets resulting from nonstoichiometric magnetite are also present, except for a coating on the rock Mazatzal, where a hematite-like sextet is present. Greater proportions of ferric-bearing phases are associated with undisturbed soils and rock surfaces as compared to fresh rock surfaces exposed by grinding. The ubiquitous presence of olivine in soil suggests that physical rather than chemical weathering processes currently dominate at Gusev crat…
Spatial analysis of the relationship between mortality from cardiovascular and cerebrovascular disease and drinking water hardness
2004
Journal Article; Research Support, Non-U.S. Gov't; Reproduced with permission from Environmental Health Perspectives. Previously published scientific papers have reported a negative correlation between drinking water hardness and cardiovascular mortality. Some ecologic and case-control studies suggest the protective effect of calcium and magnesium concentration in drinking water. In this article we present an analysis of this protective relationship in 538 municipalities of Comunidad Valenciana (Spain) from 1991-1998. We used the Spanish version of the Rapid Inquiry Facility (RIF) developed under the European Environment and Health Information System (EUROHEIS) research project. The strateg…
Dietary magnesium intake is inversely associated with mortality in adults at high cardiovascular disease risk
2013
The relation between dietary magnesium intake and cardiovascular disease (CVD) or mortality was evaluated in several prospective studies, but few of them have assessed the risk of all-cause mortality, which has never been evaluated in Mediterranean adults at high cardiovascular risk. The aim of this study was to assess the association between magnesium intake and CVD and mortality risk in a Mediterranean population at high cardiovascular risk with high averagemagnesium intake. The present study included 7216 men and women aged 55-80 y fromthe PREDIMED (Prevencíon con Dieta Mediterŕanea) study, a randomized clinical trial. Participants were assigned to 1 of 2 Mediterranean diets (supplemente…
COMMENTARY TO THE LETTER TO THE EDITOR
2011
mrh.2011.0274 Auteur(s) : Mario Barbagallo mabar@unipa.it, Ligia J Dominguez Geriatric Unit, Dept. of Internal Medicine and Emergent Pathologies, University of Palermo, Italy Correspondence: M. Barbagallo Dear Editor, We thank Dr Kisters for his comments; we agree with the potentiality of magnesium supplementation in the management of hypertension. However, although our data show the effectiveness of magnesium supplementation to improve endothelial vascular function [1], we would be more [...]
Die Bedeutung von Magnesium für Insulinresistenz, metabolisches Syndrom und Diabetes mellitus - Empfehlungen der Gesellschaft für Magnesium-Forschung…
2014
Mangel an Magnesium (Mg) ist ein wichtiges und haufiges Begleitphanomen bei Patienten mit Diabetes mellitus oder Vorstufen eines Diabetes Typ 2 wie dem Metabolischen Syndrom. Mg-Mangel erhoht das Risiko, einen Diabetes Typ 2 zu entwickeln. Diese Empfehlungen resumieren die gegenwartigen Kenntnisse zur Physiologie des Mg im Kohlenhydratstoffwechsel und die pathophysiologischen Folgen des Mg-Mangels bei Diabetikern. Diabetiker und Patienten mit dessen Vorstufen profitieren von vier Kategorien der Mg-Wirkmechanismen: Insulin-sensitizing-Effekt, Ca-Antagonismus, Stress-Regulation und Endothel-stabilisierender Effekt. Klinische Studiendaten mit Mg-Comedikation zeigen verminderte Insulinresistenz…