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José de San Martín, Argentina

Gutkowski K.,Gerencia de Quimica | Freire E.,Comision Nacional de la Energia Atomica | Freire E.,University of Buenos Aires | Baggio R.,Comision Nacional de la Energia Atomica
Acta Crystallographica Section C: Crystal Structure Communications | Year: 2011

The title complex, {[Pr4(C2H3O 2)10(C2O4)(H2O)2] ·2H2O} n , was synthesized under hydro-thermal conditions from praseodymium acetate and the ionic liquid 1-butyl-3-methyl-imidazolium chloride via an in situ oxalate-ligand synthesis. The compound is a two-dimensional polymer and in the structure presents tightly bound planes parallel to (100), which are in turn linked into a three-dimensional network by hydrogen bonds involving both coordinated and solvent water mol-ecules. The oxalate anion lies across an inversion centre and acts as a bridge between pairs of Pr atoms within a tetra-nuclear segment of the polymer. © 2011 International Union of rystallography. Source


Murina E.L.,Gerencia de Quimica | Pastorino C.,CONICET | Fernandez-Prini R.,Gerencia de Quimica | Fernandez-Prini R.,Argentinean Institute of Chemical Physics for Materials, Environment and Energy
Chemical Physics Letters | Year: 2015

Abstract We studied the entrance mechanism of methane molecules into bulk water by Molecular Dynamics simulation over a broad time window. We corroborated that the presence of absorbed methane, under the studied thermodynamic state (298 K and roughly 10 MPa), does not influence the molecular configuration of water interface. Some representative interfacial trajectories were analyzed in detail and we propose an entrance mechanism in which interfacial water is not actively involved in the dissolution process. Finally, we described the Helmholtz Free Energy profile through the interface and obtained the dissolution free energy of methane in water. © 2015 Elsevier B.V. Source


Martinez E.D.,Gerencia de Quimica | Granja L.,Gerencia de Investigacion y Aplicaciones | Bellino M.G.,Gerencia de Quimica | Soler-Illia G.J.A.A.,Gerencia de Quimica
Physical Chemistry Chemical Physics | Year: 2010

The space-resolved electrical conductivity of patterned silver nanoparticle (NP) arrays embedded in mesoporous TiO2 thin films was locally evaluated using a conductive-tip AFM. A remarkable conductivity dependence on the film mesostructure and metal NP loading was observed, confirming a three-dimensional current flow throughout the nanocomposite. © 2010 the Owner Societies. Source


Menendez A.M.,University of Belgrano | Menendez A.M.,Instituto Argentino Of Educacion E Investigacion En Nutricion | Farias S.S.,Gerencia de Quimica | Servant R.,Gerencia de Quimica | And 6 more authors.
Nutricion Hospitalaria | Year: 2014

Introduction: Aluminum (Al) is a toxic element which may contaminate pharmaceutical products used as individual components to prepare total parenteral nutrition mixtures (TPN). Objectives: 1) to determine Al levels in the individual components used to prepare TPN mixtures; 2) to compare detected Al levels with those imposed by international regulations (FDA); 3) to calculate the total amount of Al administered to adult and children receiving those typical TPN mixtures. Methods: Al was determined by Inductively Coupled Plasma- Atomic Emission Spectrometry (ICP-OES) (Perkin Elmer OPTIMA 5100 DV) in 44 individual products, from different labs and lots, belonging to 16 components available in Argentina: dextrose and amino acids for adult formulas and for pediatric formulas: lípids; potassium chloride; sodium chloride, magnesium sulfate; sodium phosphate; calcium gluconate; sodium glycerophosphate, zinc sulfate; multitrace elements; steril water (ampoules and great volume presentations). Results: Al levels were detected in 43 of the 44 the studied components, except sterile water. The components of large volume presented between 249 y 1, 580 μg Al/ L, between 4 and 180 times FDA established levels (25 μg Al/ L). Small volume components presented Al levels between 85 y 4, 909 g/ L, not declared in labels. Conclusions: The highest amounts of Al were detected in calcium gluconate, sodium phosphate and multitrace elements. 2) Usually prescribed TPN mixtures would have higher Al levels than those accepted by FDA regulation; 3) The highest aluminum concentration was provided by dextrose, amino acids and lipids in adult TPN mixtures. In neonate TPN mixtures, Al highest amounts were provided by dextrose and calcium gluconate. The calculated concentration of Al in TPN mixtures was higher than those stipulated by international regulation (5 μg Al/kg (body weight)/ d). It would be advisable for manufacturers to declare the content of aluminum in the label, with the aim of avoiding toxicities which would compromise the critical patients' evolution. Source

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