Efecto de los vapores de los ácidos acético y fórmico en la degradación y patinado del cobre

La conservación del Patrimonio Histórico Artístico exige conocer los mecanismos de degradación de los materiales que lo componen. En el caso de los materiales metálicos, últimamente se ha comprobado que los ácidos orgánicos presentes en interiores de museos y vitrinas pueden suponer una amenaza para la conservación de los mismos. El cobre es, posiblemente, el metal más importante en el Patrimonio Histórico Artístico, en estado mas o menos puro o formando aleaciones, principalmente bronce o latón. Sin embargo, no existen apenas estudios del efecto de los vapores de los ácidos orgánicos sobre el cobre. En la presente Memoria se ha estudiado el efecto de los vapores de los principales ácidos orgánicos presentes en interiores, acético y fórmico, en la degradación y formación de la pátina sobre el cobre, a distintas concentraciones entre 10 y 300 ppm y al 40,60,80 y 100% de humedad relativa, durante un tiempo de exposición de 21 días. A efectos comparativos, se ha estudiado la corrosión del cobre a las distintas humedades relativas en atmósferas sin contaminar por ácidos. Se ha estudiado la velocidad de corrosión mediante ensayos gravimétricos y se han caracterizado los productos de corrosión presentes en la patina formada por medio de métodos electroquímicos, difracción de rayos X, espectroscopía infrarroja por transformada de Fourier, microscopía electronica de barrido, análisis termodiferencial y termogravimetrico y espectroscopia fotoelectronica de rayos X. Para lograr una correcta interpretación de los espectros obtenidos por esta ultima técnica, se han analizado patrones de acetato, formato e hidróxido de cobre. Los resultados obtenidos han mostrado que en las condiciones estudiadas los ácidos acético y fórmico provocan un importante corrosión en el cobre, que lleva aparejada un gran cambio en el aspecto del mismo, formándose una pátina de colores marrones más o menos oscuros, grises azulados o distintos tonos de verdes, dependiendo de las concentraciones de los contaminantes y la humedad relativa. La velocidad de corrosión causada por el ácido acético es mayor en las muestras expuestas a las mayores concentraciones y humedades relativas. Sin embargo, a las concentraciones de ácidos menores y humedades relativas más bajas el acido formico resulta más corrosivo para el cobre. Los principales componentes encontrados en las patrinas han sido cuprita (Cu2O), acetato de cobre dihidratado (Cu(CH3COO)2.2H2O) e hidroxiacetato de cobre dihidratado, (Cu4(OH)(CH3COO)7.2H2O), en las muestras expuestas a vapores de ácido acetico, y formiato de cobre tetrahidratado (Cu(HCOO)2.4H2O) e hidróxido cúprico hidratado (Cu(OH)2.H2O) en las muestras expuestas a los vapores de ácido fórmic

Use of EIS for the evaluation of the protective properties of coatings for metallic cultural heritage: a review.

The best way to reduce the degradation of metallic cultural heritage is through preventive conservation measures but, in many cases, it is not possible to obtain adequate environmental conditions, and it is necessary to apply coatings to the artefacts in order to protect them against corrosion. There is a continuous search in the metal conservation community for new and improved coatings that provide a better protection to the objects, while respect the special requirements of the conservation-restoration ethics. While electrochemical techniques have a long tradition in conservation-restoration treatments for metallic cultural heritage, the evaluation of protective coatings using electrochemical impedance spectroscopy (EIS) has only been used very recently. EIS is a very well established method to investigate metal coatings for general purposes, and have many advantages that make it especially suitable for testing coatings for metallic works of art. This paper makes a review of the use of EIS for testing coatings for metallic cultural heritage, from the first publications in the mid nineties of the last century to the last papers. The experimental setup used, the types of coatings and metals investigated and the interpretation of the results is reviewed and compared with the use of EIS for testing general purpose anticorrosive coatingsPeer reviewe

La Red de Ciencia y Tecnología para la Conservación del Patrimonio Cultural como plataforma de colaboración

13 páginas, 15 referencias.-- Jornada celebrada los días 24-25 de mayo de 2012, en el contexto de la VIII Bienal de la Restauración y Gestión del Patrimonio AR&PA 2012, en Valladolid.-- Las Jornadas Técnicas Arespa-Investigación y Empresa, han sido promovidas por la Delegación del CSIC en Castilla y León, la Red de Ciencia y Tecnología para la Conservación del Patrimonio Cultural (TechoHeritage) y la Asociación Española de Empresas de Restauración del Patrimonio Histórico (Arespa).El carácter multidisciplinar de la investigación en conservación del patrimonio cultural hace especialmente adecuado y necesario el establecimiento de redes que pongan en contacto y permitan la colaboración de los distintos actores implicados: universidades, centros de investigación, instituciones culturales y empresas. Con este fin, se creó en 2011 la Red TechnoHeritage (Red de Ciencia y Tecnología para la Conservación del Patrimonio Cultural), con la financiación del Ministerio de Economía y Competitividad. TechnoHeritage aglutina en la actualidad a 80 grupos de los ámbitos citados. En la presente publicación se presentan los orígenes de la Red, las motivaciones para su puesta en marcha, los objetivos que se pretenden alcanzar y algunas de las actividades que se han llevado a cabo.Al Ministerio de Economía y Competitividad por la financiación de la Red dentro del Programa de Acciones Complementarias del Plan Nacional de I+D+i 2008-2011 (HAR2010-11432-E).Peer reviewe

Corrosión y protección de metales para la construcción y el patrimonio cultural

4 páginas, 2 figuras. Ed. Miguel Ángel Rogerio Candelera y Cesáreo Sáiz Jiménez. Primera Reunión de la Red de Ciencia y Tecnología para la Conservación del Patrimonio (Madrid, 28-29 de junio de 2011).La corrosión, es decir, la reacción química del metal con el medio en que se encuentra, es la principal causa de degradación del patrimonio cultural metálico. La naturaleza y estructura del material metálico, y el medio en el que se encuentra (sea el medio atmosférico exterior o interior de un museo o vitrina; el agua del mar o la tierra en los objetos sumergidos o enterrados; o incluso componentes de otra naturaleza que forman parte del propio objeto) condiciona los mecanismos y velocidad de deterioro. Es por lo tanto fundamental, si queremos asegurar correcta conservación de este patrimonio metálico, conocer los mecanismos por los que se produce este deterioro y desarrollar metodologías y estrategias para su protección, especialmente adaptadas a las características y necesidades peculiares de este tipo de objetos.Peer reviewe

Electrochemical characterization of organic coatings for protection of historic steel artefacts

Figuras en el archivo zipElectrochemical techniques are mainly known in the field of cultural heritage conservation as a tool for the elimination of corrosion layers or the removal of chlorides. However, these techniques are also a valuable tool for assessing the anti-corrosive efficiency of protective coatings. The aim of this study was to evaluate the performance of different coatings for their use in metallic heritage conservation using polarization resistance (Rp) and electrochemical impedance spectroscopy (EIS). Carbon steel samples were prepared to simulate the surface composition and morphology of historic steel artefacts, and coated by a conservator-restorer following the common practices in conservation treatments. Three commercial organic coatings have been studied: a microcrystalline wax (RenaissanceTM) and a methyl acrylate/ethyl methacrylate copolymer resin (ParaloidTM B-72) dissolved in acetone –both them commonly used in conservation and restoration treatments– and a ethylene copolymer wax emulsion in water (PoligenTM ES- 91009), that has not been used so far for this purposes. Four commercial corrosion inhibitor additives were added to the ParaloidTM B-72 resin and PoligenTM ES-91009 wax. The additives were commercial preparations with the following known active components: a blend of triazoles (M435), an ammonium salt of tricarboxylic acid (M370), a calcium sulphonate (M109), and a bis-oxazoline (Alkaterge-TTM). Rp and EIS results showed that the best protection of the steel specimens was afforded by PoligenTM ES-91009 when applied in thick layers. None of the additives have shown a clear improvement of the protection properties of the coatings, and one of them impaired the barrier effect of the coating.Acknowledgements The authors express their gratitude to the Sixth Framework Programme of the European Commission for financial support of PROMET Project (Contract 509126). D.M. Bastidas expresses his gratitude to the CSIC of Spain for his contract under the I3P Programme, co-financed by the European Social Fund.Peer reviewe

Assessment of elemental composition in commercial fish of the Bay of Cádiz, Southern Iberian Peninsula

The assessment of trace metal content in our fish diet is important due to the adverse effect on human health. Despite the increasing interest about the fish quality, little information is available for Southern Spain, a region characterized by high seafood intake. Nine species from the Bay of Cádiz with high commercial value were selected. Similar values were measured in the nine studied species for most of the elements, except for the macroelements Ca and S, and the microelements Fe, Mn and As, which showed significant differences among species. Metal Pollution Index (MPI) did not differ among species, and it was similar to those obtained for other Atlantic and Mediterranean locations. The values measured for the nine species were below the health limits provided by World, European and Spanish legislations, indicating that, in general terms, consumption of these species is safe in the study area.We are very grateful to Dr. P. Burgos for chemical analysis conducted in IRNAS-CSIC (Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla). During the study, ID-A enjoyed a grant "Margarita Salas" financed by the European Union (Next Generation EU) and the Ministerio de Universidades of Spain

What remains of the future: sustainability through heritage

Coordinators : Felipe Criado Boado (INCIPIT, CSIC), Blanca Ramírez Barat (CENIM, CSIC).Heritage is increasingly being recognized as a key element for social cohesion, sustainable socioeconomic development and people’s welfare. Resources dedicated to heritage conservation have gone from being considered an expense to being regarded as an investment, with a high revenue. The heritage industry has been an active part of this transformations in recent decades, it has generated employment, contributed to the worldwide expansion of tourism and has become a coveted sign of identity for political communities. Today there is no social or political process that does not use heritage in some way. Hence the actuality of the subject, and the importance of an organization such as the CSIC having research capabilities in this field

Forest Restoration in a Fog Oasis: Evidence Indicates Need for Cultural Awareness in Constructing the Reference

Background: In the Peruvian Coastal Desert, an archipelago of fog oases, locally called lomas, are centers of biodiversity and of past human activity. Fog interception by a tree canopy, dominated by the legume tree tara (Caesalpinia spinosa), enables the occurrence in the Atiquipa lomas (southern Peru) of an environmental island with a diverse flora and high productivity. Although this forest provides essential services to the local population, it has suffered 90% anthropogenic reduction in area. Restoration efforts are now getting under way, including discussion as to the most appropriate reference ecosystem to use. Methodology/Principal Findings: Genetic diversity of tara was studied in the Atiquipa population and over a wide geographical and ecological range. Neither exclusive plastid haplotypes to loma formations nor clear geographical structuring of the genetic diversity was found. Photosynthetic performance and growth of seedlings naturally recruited in remnant patches of loma forest were compared with those of seedlings recruited or planted in the adjacent deforested area. Despite the greater water and nitrogen availability under tree canopy, growth of forest seedlings did not differ from that of those recruited into the deforested area, and was lower than that of planted seedlings. Tara seedlings exhibited tight stomatal control of photosynthesis, and a structural photoprotection by leaflet closure. These drought-avoiding mechanisms did not optimize seedling performance under the conditions produced by forest interception of fog moisture. Conclusions/Significance: Both weak geographic partitioning of genetic variation and lack of physiological specialization of seedlings to the forest water regime strongly suggest that tara was introduced to lomas by humans. Therefore, the most diverse fragment of lomas is the result of landscape management and resource use by pre-Columbian cultures. We argue that an appropriate reference ecosystem for ecological restoration of lomas should include sustainable agroforestry practices that emulate the outcomes of ancient uses

Effect of an Intensive Weight-Loss Lifestyle Intervention on Kidney Function: A Randomized Controlled Trial

Introduction: Large randomized trials testing the effect of a multifactorial weight-loss lifestyle intervention including Mediterranean diet (MedDiet) on renal function are lacking. Here, we evaluated the 1-year efficacy of an intensive weight-loss intervention with an energy-reduced MedDiet (erMedDiet) plus increased physical activity (PA) on renal function. Methods: Randomized controlled "PREvención con DIeta MEDiterránea-Plus"(PREDIMED-Plus) trial is conducted in 23 Spanish centers comprising 208 primary care clinics. Overweight/obese (n = 6,719) adults aged 55-75 years with metabolic syndrome were randomly assigned (1:1) to an intensive weight-loss lifestyle intervention with an erMedDiet, PA promotion, and behavioral support (intervention) or usual-care advice to adhere to an energy-unrestricted MedDiet (control) between September 2013 and December 2016. The primary outcome was 1-year change in estimated glomerular filtration rate (EGFR). Secondary outcomes were changes in urine albumin-to-creatinine ratio (UACR), incidence of moderately/severely impaired EGFR (<60 mL/min/1.73 m2) and micro-to macroalbuminuria (UACR ≥30 mg/g), and reversion of moderately (45 to <60 mL/min/1.73 m2) to mildly impaired GFR (60 to <90 mL/min/1.73 m2) or micro-to macroalbuminuria. Results: After 1 year, EGFR declined by 0.66 and 1.25 mL/min/1.73 m2 in the intervention and control groups, respectively (mean difference, 0.58 mL/min/1.73 m2; 95% CI: 0.15-1.02). There were no between-group differences in mean UACR or micro-to macroalbuminuria changes. Moderately/severely impaired EGFR incidence and reversion of moderately to mildly impaired GFR were 40% lower (HR 0.60; 0.44-0.82) and 92% higher (HR 1.92; 1.35-2.73), respectively, in the intervention group. Conclusions: The PREDIMED-Plus lifestyle intervention approach may preserve renal function and delay CKD progression in overweight/obese adults.This work was supported by the official Spanish Institutions for funding scientific biomedical research, CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN) and Instituto de Salud Carlos III (ISCIII), through the Fondo de Investigación para la Salud (FIS), which is cofunded by the European Regional Development Fund (5 coordinated FIS projects leaded by J.S.-S and J.V., including the following projects: PI13/00673, PI13/00492, PI13/00272, PI13/01123, PI13/00462, PI13/00233, PI13/02184, PI13/00728, PI13/01090, PI13/01056, PI14/01722, PI14/00636, PI14/00618, PI14/00696, PI14/01206, PI14/01919, PI14/00853, PI14/01374, PI14/00972, PI14/00728, PI14/01471, PI16/00473, PI16/00662, PI16/01873, PI16/01094, PI16/00501, PI16/00533, PI16/00381, PI16/00366, PI16/01522, PI16/01120, PI17/00764, PI17/01183, PI17/00855, PI17/01347, PI17/00525, PI17/01827, PI17/00532, PI17/00215, PI17/01441, PI17/00508, PI17/01732, PI17/00926; PI19/00957, PI19/00386, PI19/00309, PI19/01032, PI19/00576, PI19/00017, PI19/01226, PI19/00781, PI19/01560, and PI19/01332); the Especial Action Project entitled Implementación y evaluación de una intervención intensiva sobre la actividad física Cohorte PREDIMED-Plus grant to J.S.-S.; the European Research Council (Advanced Research Grant 2014–2019; agreement #340918) granted to M.Á.M.-G.; the Recercaixa (No. 2013ACUP00194) grant to J.S.-S.; grants from the Consejería de Salud de la Junta de Andalucía (PI0458/2013, PS0358/2016, and PI0137/2018); the PROMETEO/2017/017 grant from the Generalitat Valenciana; the SEMERGEN grant; funds from the European Regional Development Fund (CB06/03); International Nut & Dried Fruit Council – FESNAD (Long-term effects of an energyrestricted Mediterranean diet on mortality and cardiovascular disease 2014–2015, No. 201302) (PI: M.Á.M.-G.); the AstraZeneca Young Investigators Award in Category of Obesity and T2D 2017 (PI: D.R.); grant of support to research groups No. 35/2011 (Balearic Islands Gov.; FEDER funds) (J.A.T. and C.B.); the JR17/00022 (ISCIII) grant to O.C.; the Boosting young talent call grant program for the development of IISPV research projects 2019–2021 (Ref.: 2019/IISPV/03 grant to A.D.-L.); the Societat Catalana d’Endocrinologia i Nutrició (SCEN) Clinical-Research Grant 2019 (IPs: J.S.-S. and A.D.-L.). Collaborative Nutrition and/or Obesity Project for Young Researchers 2019 supported by CIBEROBN entitled Lifestyle Interventions and Chronic Kidney Disease: Inflammation, Oxidative Stress and Metabolomic Profile (LIKIDI study) grant to A.D.-L