Artículos, informes y presentaciones en Congresos

URI https://digital.cic.gba.gob.ar/handle/11746/96

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  • Artículo
    Acceso Abierto
    Corrosión localizada del acero inoxidable austenítico en medio de cultivo celular y evaluación de la citotoxicidad de los iones liberados
    (2021) Parisi, Julieta Marcia; Castrogiovanni, Daniel; Grau, Jorge Enrique; Gregorutti, Ricardo Walter; Elsner, Cecilia Inés
    El acero inoxidable austenítico ASTM F745 ha sido sometido a corrosión localizada en medio de cultivo celular y solución acuosa de NaCl, cuyas concentraciones de cloruro fueron 4413,2 mg L-1 y 5423,1 mg L-1, respectivamente. Se ha observado que la susceptibilidad a la corrosión localizada fue menor en el medio de cultivo debido a su menor contenido de cloruros. El Fe fue el metal más liberado en ambos medios durante el proceso de corrosión. Las concentraciones fueron 0,570 mg L-1 en la solución acuosa de NaCl y 0,480 mg L-1 en el medio de cultivo. Las concentraciones de Cr y Mo fueron similares en ambos medios, habiendo sido 0,040 mg L-1 y 0,010 mg L-1, respectivamente, mientras que Ni solo se detectó en la solución acuosa de NaCl, 0,100 mg L-1. Estas concentraciones de iones liberados no provocaron efectos citotóxicos en células similares a osteoblastos.
  • Artículo
    Acceso Abierto
    Natural compounds as potential algaecides for waterborne paints
    (2018) Gómez de Saravia, Sandra Gabriela; Rastelli, Silvia Elena; Blustein, Guillermo; Viera, Marisa
    To eliminate and prevent the formation of phototrophic biofilms on painted walls, chemicals are added to paints. These chemicals, in general, also have toxic effects on the environment. Plants synthesize secondary metabolites which have antimicrobial properties and that may be a sustainable alternative to traditional biocides. In this work, algal species isolated from biofilms formed on deteriorated painted surfaces were taxonomically identified. Observations with the optical microscope revealed the presence of mixed biofilms composed of algae belonging to the Cyanophyta, Chlorophyta, and Streptophyta divisions. The algaecide effect of natural compounds of vegetal origin such as anisole, eugenol, guaiacol, and thymol was evaluated by the microatmosphere technique. Growth inhibition of phototrophic organisms was obtained with thymol in all the concentrations used. Eugenol and guaiacol showed a total growth inhibition at the highest concentration assayed (300 lmol cm 2) and a decrease in growth at 40 lmol cm 2, while anisole did not exert any inhibitory action at the assayed concentrations. Due to these results, eugenol, thymol, and guaiacol were incorporated in an exterior waterborne paint at a concentration of 2%. Samples painted with these formulations were not colonized by algae, indicating that these compounds could be used as biocides in paint formulations
  • Artículo
    Acceso Abierto
    Natural compounds as additives in paints for controlling algae growth
    (2019) Gómez de Saravia, Sandra Gabriela; Rastelli, Silvia E.; Viera, Marisa
    Algae are a diverse group of photosynthetic organisms ranging from microscopic single-cell micro-organisms to very large organisms such as seaweed. Microalgae belonging to Chlorophyta (green algae) and Cianophyta (blue-green algae) commonly occur in biofilms. Actually, these phototrophic biofilms are complex microbial communities formed by cyanobacteria, microalgae and heterotrophs (1) all embedded in a mucilaginous matrix of exopolymeric substances (EPS), mainly composed of polysaccharides ranging between 50% and 90% (2). Phototrophic biofilms can produce aesthetic effect and deterioration of building painted surfaces (3). It is a common practice to treat these surfaces with mechanical brushes and/or biocides in order to eradicate the microorganisms present. Several chemicals have been used for this purpose, such as acids, pyridines (4), quaternary ammonium salts (5) and organometallic compounds (6). However, some of these products have been banned over time due to their associated environmental and health hazards (7). An alternative to those compounds, it is the use of ecofriendly natural substances with known biocidal properties. The approach of using natural substances and herbs has been gaining prominence in the field of cultural heritage and conservation sciences since the 2000s (8). Here we present the evaluation of the algaecide properties of isoeugenol, vanillic acid and carvacrol incorporated in an acrylic waterborne paint formulation.
  • Artículo
    Acceso Abierto
    Physical, mechanical properties and antimicrobial analysis of a novel CaO·Al2O3 compound reinforced with Al or Ag particles
    (2019) Gómez de Saravia, Sandra Gabriela; Rastelli, Silvia E.; Ortega-Avilés, Mayahuel; González-Morán, Carlos O.; Rocha-Rangel, Enrique; Miranda-Hernández, José G.
    Ceramic-metal (CaO·Al2O3–Al and CaO·Al2O3–Ag) compounds were prepared by mechanical milling and consolidated through an in-situ sintering process. The aim of this work is to study the effects of the Al and Ag particles to ceramic-base compound, primarily in the microstructure, and its mechanical and antimicrobial properties. Chemical systems with a 1:1M ratio between CaCO3 and Al2O3 powder were formed, with the addition of 10 wt% Al or 10 wt% Ag, respectively. The compound material that consolidated were microstructurally characterized through X-ray diffraction, scanning electron microscopy, optic microscopy, and X-ray computed tomography. In addition, the hardness, the fracture toughness, the transversal elastic modulus, and the antimicrobial property were evaluated. The results of X-ray diffraction identified the formation of the calcium aluminate phases, such as CaO·6Al2O3 (hibonite:CA6), CaO·2Al2O3 (grossite:CA2), and CaO·Al2O3 (krotite:CA); as well as Al and Ag were identified in its respective system. In addition, the mechanical properties show changes compared to the reference material that was synthesized under the same conditions and, finally, these materials also have an antimicrobial effect, against the Staphylococcus bacterium that is common in the oral cavity, when studied in synthetic saliva.
  • Comunicacion
    Acceso Abierto
    Natural compounds as potential algaecides for waterborne paints
    (2018) Gómez de Saravia, Sandra Gabriela; Rastelli, Silvia E.; Blustein, Guillermo; Viera, Marisa
    To eliminate and prevent the formation of phototrophic biofilms on painted walls, chemicals are added to paints. These chemicals, in general, also have toxic effects on the environment. Plants synthesize secondary metabolites which have antimicrobial properties and that may be a sustainable alternative to traditional biocides. In this work, algal species isolated from biofilms formed on deteriorated painted surfaces were taxonomically identified. Observations with the optical microscope revealed the presence of mixed biofilms composed of algae belonging to the Cyanophyta, Chlorophyta, and Streptophyta divisions. The algaecide effect of natural compounds of vegetal origin such as anisole, eugenol, guaiacol, and thymol was evaluated by the microatmosphere technique. Growth inhibition of phototrophic organisms was obtained with thymol in all the concentrations used. Eugenol and guaiacol showed a total growth inhibition at the highest concentration assayed (300 lmol cm 2) and a decrease in growth at 40 lmol cm 2, while anisole did not exert any inhibitory action at the assayed concentrations. Due to these results, eugenol, thymol, and guaiacol were incorporated in an exterior waterborne paint at a concentration of 2%. Samples painted with these formulations were not colonized by algae, indicating that these compounds could be used as biocides in paint formulations.