The Experts below are selected from a list of 1797 Experts worldwide ranked by ideXlab platform
Kerstin Elert - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Animal Glue on mineralogy, strength and weathering resistance of calcium sulfate-based composite materials
Cement and Concrete Composites, 2019Co-Authors: Kerstin Elert, Cristina Benavides-reyes, Carolina CardellAbstract:Abstract Calcium sulfate (gypsum, bassanite, and anhydrite) has been widely used since ancient times as decorative plaster and painting grounds, often mixed with organic additives (e.g., Animal Glue). In order to evaluate the effect of organic additives on gypsum setting and on the product's final properties, calcium sulfate-based plaster samples, with and without the addition of Animal Glue, were subjected to accelerated weathering and mechanical testing. Test results were related to the samples' mineralogical composition. Animal Glue improved mechanical properties and weathering resistance, but retarded gypsum setting and resulted in long-term stabilization of metastable bassanite and anhydrite. Accelerated weathering (wetting/drying cycles) resulted in changes in mineral phases and micro-texture, affecting mechanical properties and facilitating deterioration due to phase transition-related volume changes. Findings are discussed with respect to applications of calcium sulfate-based materials in conservation and rehabilitation interventions.
-
Influence of Animal Glue on mineralogy, strength and weathering resistance of lime plasters
Construction and Building Materials, 2019Co-Authors: Kerstin Elert, Cristina Benavides-reyes, Rosa Maria García Sánchez, Fátima Linares OrdóñezAbstract:Abstract In order to optimize lime plasters for conservation purposes, the influence of Animal Glue on the mineralogical evolution, mechanical properties, and weathering resistance was studied. The organic additive caused a decrease in carbonation rate and affected mechanical properties negatively, facilitating the formation of large air bubbles in the plaster matrix. However, the weathering resistance (water spraying/SO2 exposure) improved significantly. The organic additive also reduced crack formation and formed a physical barrier around the calcite crystals, which delayed sulfation. Lime-based composite materials are a valuable alternative to conventional lime plasters, showing improved adherence to the substrate and no significant color changes.
Fátima Linares Ordóñez - One of the best experts on this subject based on the ideXlab platform.
-
Influence of Animal Glue on mineralogy, strength and weathering resistance of lime plasters
Construction and Building Materials, 2019Co-Authors: Kerstin Elert, Cristina Benavides-reyes, Rosa Maria García Sánchez, Fátima Linares OrdóñezAbstract:Abstract In order to optimize lime plasters for conservation purposes, the influence of Animal Glue on the mineralogical evolution, mechanical properties, and weathering resistance was studied. The organic additive caused a decrease in carbonation rate and affected mechanical properties negatively, facilitating the formation of large air bubbles in the plaster matrix. However, the weathering resistance (water spraying/SO2 exposure) improved significantly. The organic additive also reduced crack formation and formed a physical barrier around the calcite crystals, which delayed sulfation. Lime-based composite materials are a valuable alternative to conventional lime plasters, showing improved adherence to the substrate and no significant color changes.
Domenico Pangallo - One of the best experts on this subject based on the ideXlab platform.
-
Biocleaning of historical documents: The use and characterization of bacterial enzymatic resources
International Biodeterioration & Biodegradation, 2019Co-Authors: Lenka Jeszeová, Vladena Bauerová-hlinková, Lucia Kraková, Radka Benžová, Marianna Gluštíková, Alena Šišková, Zuzana Kisová, Matej Planý, Domenico PangalloAbstract:Abstract Living microorganisms have been used for biocleaning of cultural heritage items, but the application of only extracellular enzyme mixtures (EEMs) from isolated bacteria has not previously been considered for biorestoration work. In this investigation, the proteolytic characteristics of the EEMS from three bacterial isolates (Paracoccus sp., Bacillus flexus and Exiguobacterium undae) were determined and their extent of inhibition in the presence of the proteolytic inhibitors 1,10-phenanthroline monohydrate, EDTA, leupeptin, bestatin and various metal ions was examined. These EEMs were used to remove the Animal Glue present on the spine of bound newspapers. FT-IR analysis showed that Animal Glue was effectively removed by a solution of tylose and EEM. The EEM of E. undae gave the best results. Our study describes a simple strategy for the production and characterization of enzymatic mixtures targeted to the degradation of a specific substrate and their subsequent use for biocleaning historical objects.
-
Biochemical and proteomic characterization of the extracellular enzymatic preparate of Exiguobacterium undae, suitable for efficient Animal Glue removal
Applied Microbiology and Biotechnology, 2018Co-Authors: Lenka Jeszeová, Vladena Bauerová-hlinková, Peter Baráth, Andrea Puškárová, Mária Bučková, Lucia Kraková, Domenico PangalloAbstract:In this work, we describe the preparation and characterization of a biopreparate for efficient and rapid Animal Glue removal. The biopreparate is based on the extracellular proteolytic enzymes of an Exiguobacterium undae environmental isolate. Liquid chromatography-mass spectrometry analysis showed that the biopreparate is predominantly composed of hydrolytic enzymes—proteases and peptidases, nucleases, peptide ABC transporter substrate-binding proteins, and a phosphatase. The two main proteins present are bacillolysin and a peptide ABC transporter substrate-binding protein. Inhibition and proteomic analyses of the biopreparate revealed that bacillolysin, a neutral metalloendopeptidase, is mainly responsible for its proteolytic activity. This biopreparate was able to satisfactorily remove two types of Animal Glue from different kinds of material surfaces. These results suggest that this biopreparate could serve as a potential new tool for the restoration of historical objects rather than living microorganisms.
Cristina Benavides-reyes - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Animal Glue on mineralogy, strength and weathering resistance of calcium sulfate-based composite materials
Cement and Concrete Composites, 2019Co-Authors: Kerstin Elert, Cristina Benavides-reyes, Carolina CardellAbstract:Abstract Calcium sulfate (gypsum, bassanite, and anhydrite) has been widely used since ancient times as decorative plaster and painting grounds, often mixed with organic additives (e.g., Animal Glue). In order to evaluate the effect of organic additives on gypsum setting and on the product's final properties, calcium sulfate-based plaster samples, with and without the addition of Animal Glue, were subjected to accelerated weathering and mechanical testing. Test results were related to the samples' mineralogical composition. Animal Glue improved mechanical properties and weathering resistance, but retarded gypsum setting and resulted in long-term stabilization of metastable bassanite and anhydrite. Accelerated weathering (wetting/drying cycles) resulted in changes in mineral phases and micro-texture, affecting mechanical properties and facilitating deterioration due to phase transition-related volume changes. Findings are discussed with respect to applications of calcium sulfate-based materials in conservation and rehabilitation interventions.
-
Influence of Animal Glue on mineralogy, strength and weathering resistance of lime plasters
Construction and Building Materials, 2019Co-Authors: Kerstin Elert, Cristina Benavides-reyes, Rosa Maria García Sánchez, Fátima Linares OrdóñezAbstract:Abstract In order to optimize lime plasters for conservation purposes, the influence of Animal Glue on the mineralogical evolution, mechanical properties, and weathering resistance was studied. The organic additive caused a decrease in carbonation rate and affected mechanical properties negatively, facilitating the formation of large air bubbles in the plaster matrix. However, the weathering resistance (water spraying/SO2 exposure) improved significantly. The organic additive also reduced crack formation and formed a physical barrier around the calcite crystals, which delayed sulfation. Lime-based composite materials are a valuable alternative to conventional lime plasters, showing improved adherence to the substrate and no significant color changes.
Maria Perla Colombini - One of the best experts on this subject based on the ideXlab platform.
-
Microchemical and microscopic characterization of the pictorial quality of egg-tempera polyptych, late 14th century, Florence, Italy
Microchemical Journal, 2016Co-Authors: Magdalini Serefidou, Alessia Andreotti, Maria Perla Colombini, Susanna Bracci, Deodato Tapete, Lucia Biondi, Cristina Giannini, Daniela ParentiAbstract:This paper explores the added value of micro-chemical and microscopic approaches to gather scientific evidence that can technically explain the pictorial quality of an egg-tempera painting, and underpin assessments that otherwise would be based on naked eye observations only. Demonstration is here provided via the interdisciplinary investigation of the original technique used by Giovanni del Biondo in the polyptych Annunciation and Saints (1385 ca), Galleria dell'Accademia, Florence, Italy. The exquisite surface appearance makes this panel painting remarkable compared to artworks by coeval artists. Imaging techniques (UV, IR and IR false color), non-invasive single spot techniques (XRF and FORS spectrometry) and analytical investigations on eight selected micro-samples (ATR-FTIR, GC/MS and Py/GC–MS, ESEM-EDS) were combined to retrieve the palette and identify organic binding media and a superficial coating layer. Stratigraphic and micro-chemical data confirmed the use of a relatively simple egg-tempera technique applied on a ground made of gypsum mixed with Animal Glue, without complex stratigraphic superimposition of preparation and pictorial layers. Various pigments were identified, among which is the precious lapis lazuli. While Py/GC–MS highlight that the coating is made of dammar resin and honey mixed with Animal Glue, the results allow us to state that the painting was not intentionally varnished by Giovanni del Biondo. These outcomes shed a new light on the technical knowledge of this polyptych, and prove how challenging is the attempt to categorize egg-tempera recipes used by ancient painters at the turn of the 14th century.
-
Fast biocleaning of mediaeval frescoes using viable bacterial cells
International Biodeterioration & Biodegradation, 2012Co-Authors: Giuseppe Lustrato, G Alfano, Alessia Andreotti, Maria Perla Colombini, Giancarlo RanalliAbstract:Abstract The 14th-century fresco Stories of the Holy Fathers (size 6.10 × 15.65 m), at Camposanto Monumentale in Pisa, Italy, was painted by Buonamico Buffalmacco. The building housing it was damaged by a bomb during World War II and the fresco was quickly removed from the original walls under extremely dangerous conditions. It was detached using the “tear-off” technique with gauze and a layer of warm Animal Glue, and it was then stored by rolling it up, without adding any rigid support. In a 1960s restoration, an asbestos-cement support (eternit) was applied to the back and the gauze and thick layer of Animal Glue were removed from the front of the fresco. Early alteration phenomena such as swelling and detachment of the paint layer were noticed. In 2008, the fresco was again detached from the Camposanto wall for further restoration, which would include removal of residual traces of casein and Animal Glue from previous restorations and the reattachment of the paintings to a more suitable support. On this fresco, the combined removal in one step of casein and Animal Glue was based on the fast application of whole, viable bacterial cells of Pseudomonas stutzeri , A29 strain, to the fresco surface for a period of 2 h. An assessment of the effectiveness of the biological cleaning test was carried out using analytical pyrolysis. The results confirmed the success of this advanced biological approach for recovering valuable frescoes, and gave insight into selecting the optimum conditions for fast-treatment efficiency. Data on short- and medium-term microbial monitoring confirm both that viable cells are not present in the fresco after biotreatment and the absence of any potentially negative effects that could have been caused by metabolism. The conclusion was that the procedure was safe, non-invasive, and risk-free. The relatively low-cost of this biological cleaning process means that this biotechnological application represents a highly competitive, cost-effective solution.
-
gc ms identification of proteins in wall painting samples a fast clean up procedure to remove copper based pigment interferences
Talanta, 2007Co-Authors: Gwenaelle Gautier, Maria Perla ColombiniAbstract:Abstract A new approach was explored to purify proteins in a multi-step procedure for the characterisation of proteinaceous materials (casein, Animal Glue, and egg) in artwork samples by gas chromatography–mass spectrometry. High concentrations of inorganic salts, such as azurite, have been found to impair the determination of protein via amino acid analysis. The effect of varying concentrations of copper-based pigments on the quantification of amino acids was evaluated through the analysis of replica paintings prepared with the three types of proteinaceous materials. Glycine, aspartic and glutamic acids are the amino acids most affected by the presence of copper salts. In the case of high concentration of salts, this interference hampers the correct identification of the proteins. To eliminate the inorganic salts, a C18 pipette tip was used to clean-up the ammonia extracts before the acidic hydrolysis step. The clean-up procedure allows us to prevent the influence of the inorganic salts and thus allows correct protein identification, though the quantitative recovery of proteinaceous material is quite low. The effectiveness of the optimised procedure was evaluated by analysing samples from two Italian wall paintings from the 13th and the 14th centuries. Without the clean-up it would not have been possible to detect the presence of a mixture of egg and Animal Glue in one case, and that of egg in the other one.
