Browsing by Author "Moreira, Patrícia R."
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- As alterações da pintura mural a fresco no Norte de PortugalPublication . Marco, Alexandra; Vieira, Eduarda; Caetano, Joaquim I.; Pintado, M. E.; Moreira, Patrícia R.Apesar de grande parte do estudo da pintura mural a fresco estar por efectuar, esta expressão artística desenvolveu-se em Portugal com intensa actividade entre os séculos XV e XVI. No Norte de Portugal, devido a uma maior escassez da matéria-prima cal, a pintura apresenta frequentemente apenas uma camada de reboco, extremamente delgada, por oposição à usual utilização de duas camadas. O suporte destas pinturas foi quase exclusivamente o granito, uma rocha com boas propriedades fisico-químicas para a execução de revestimentos de cal e tipologias decorativas associadas. A degradação das pinturas murais, além da acção humana, está relacionada com a alta porosidade do substrato, sua natureza carbonatada, a presença de água nas paredes e as condições ambientais. A conjugação destes agentes é responsável pela perda significativa de área pictórica e das manchas negras inestéticas por biocolonização. No Norte de Portugal vários frescos dos séculos XV-XVI evidenciam esta alteração que mancha tanto os suportes como as pinturas – alteração de grande impacto estético que domina a atenção dos conservadores-restauradores na metodologia das intervenções. Apesar do substrato dos frescos ser principalmente inorgânico, o depósito de partículas atmosféricas e a absorção de água por capilaridade, pode promover o desenvolvimento de fungos, que segregam metabolitos como ácidos orgânicos. Diversos fungos também produzem pigmentos que variam em função da espécie, dos constituintes da pintura mural, dos factores ambientais, entre outros. O tratamento com biocidas é eficaz na erradicação dos organismos, mas não na remoção da pigmentação resultante do seu crescimento. Para assegurar intervenções éticas e sustentáveis, é fundamental conhecer tanto a natureza e comportamento dos materiais, como o seu estado de conservação actual e a identificação dos agentes e factores de degradação. Este trabalho pretende apresentar um estado da arte para este tema, incluindo os métodos mais comuns de abordagem em Conservação e Restauro para este problema.
- Antimicrobial chitosan/TPP-based coatings for the prevention of biodeterioration of outdoor stone sculpturesPublication . Silva, Nádia C.; Castro, Diana; Neto, Cláudia; Madureira, Ana Raquel; Pintado, Manuela; Moreira, Patrícia R.Outdoor stone sculptures are prone to accelerated deterioration caused by the proliferation of microorganisms in the stone. The physical, chemical and mechanical action of microorganisms on stone heritage causes aesthetic and structural changes that devalue the artworks over time. Developing more sustainable and ecological alternatives for their preventive conservation is necessary to reduce the negative environmental and human health impacts of currently used toxic biocides. Chitosan-based coatings cross-linked with citric acid and sodium tripolyphosphate (TPP) were developed for application to stone sculptures, as antimicrobial protection to inhibit the growth of degrading microorganisms. After polymerisation of the formulations, the resulting films were only partially soluble while remaining permeable to water vapour. These characteristics offer the possibility to reverse the conservation treatments, or to re-treat in regular periods, as part of programmed conservation strategies. Bacteria and fungi commonly found in stone microbiomes that contribute to biodeterioration processes were inhibited, particularly the pigment-producing yeast Rhodotorula spp., which causes discolouration of stone surfaces. The most interesting coating was successfully tested on granite, limestone and marble samples, and its presence on the stones' surfaces was confirmed by FTIR and SEM analyses. The chitosan-based coating caused no visible colour changes to the stones and reduced the wettability of granite and limestone, thus representing a potential antimicrobial protective layer for stone cultural heritage.
- Application of micro-CT for the study of mural paintings - the case of São Tiago churchPublication . Marco, Alexandra; Campos, Bruno; Vieira, Eduarda; Pintado, Manuela; Moreira, Patrícia R.
- Aspergillus versicolor and trichoderma virens as contamination agents in a musealized roman floor mosaic from the 1st centuryPublication . Moreira, Patrícia R.; Torres, Vitor; Vieira, Eduarda; Pintado, M. E.
- Assessment of drying conditions of a yeast-based solution for application on textile industrial wastewater treatment plantsPublication . Mendes, Marta; Cassoni, Ana C.; Moreira, Patrícia R.; Pintado, Manuela E.; Castro, Paula M. L.
- Basil essential oil as an alternative to commercial biocides against fungi associated with black stains in mural paintingPublication . Marco, Alexandra; Santos, Sandra; Caetano, Joaquim; Pintado, Manuela; Vieira, Eduarda; Moreira, Patrícia R.In northern Portugal it was identified that some mural paintings from the 15th and 16th centuries disclose a chromatic alteration in the form of black stains possibly of microbiological origin. In the search for its cause, samples were collected and microorganisms were isolated from selected areas of the pictorial sets of three case studies that displayed dark pigmentation. Four representative fungal isolates were selected due to their pigmentation and growth characteristics – Alternaria alternata, Alternaria tenuissima, TZ10.2.2 (possibly Pestaloptia sp.) and TZ8.2.2 (possibly Penicillium sp.). An attempt was made to encounter an innovative environmentally innocuous and green safe alternative biocide to replace the chemical-based toxic compounds currently in use. Essential oils with confirmed antifungal potential and seldom employed in the conservation of cultural heritage and even less in mural painting (Rosmarinus officinalis, Foeniculum vulgare, Citrus lemmon, Ocimum basilicum and Salvia officinalis), were tested against commercial biocides (Benzalkonium chloride, Preventol R80, CaSoPaL® and Durolith®), to evaluate their in vitro efficacy and the determination of the minimum inhibitory concentration. Basil was able to inhibit growth on all tested strains at 1.25 μl ml−1. From the commercial biocides, Benzalkonium chloride and Preventol R80 were the ones with the best performance but needed higher concentrations than basil to achieve the same result enabling this essential oil a useful alternative to commercial biocides. The literature regarding the use of essential oils in mural paintings is, apart from two known authors, practically non-existent making it a novel approach.
- Bioaugmented aerobic granular sludge reactor with a dye-decolorizing yeast for dye removal from textile industry wastewaterPublication . Mendes, Marta; Moreira, Irina S.; Moreira, Patrícia R.; Pintado, Manuela; Castro, Paula M. L.Textile industry is a worldwide economic activity that generates high volumes of harmful effluents used in fabric processing that are discharged in the environment causing potential damages to the aquatic ecosystems [1]. These discharged effluents loaded with synthetic dyes, salt and other chemicals, are resistant to biodegradation and persistent in water, and are responsible for toxicity and mutagenic effects on the aquatic life [2]. Biological methods are generally considered more environmentally friendly and of major relevance [3]. Therefore, biological alternatives to aid the decolorization of dyes in textile wastewaters need to be implemented. Aerobic granular sludge (AGS) technology has excellent potential in biodegradation of many pollutants, due to the anoxic/anaerobic zones within granules and their increased tolerance to toxicity [4]. The aim of this study is to assess the effectiveness of decolorization of textile effluents using a bioaugmented aerobic granular sludge reactor. A proved decolorizing yeast, isolated from a textile wastewater treatment plant, was selected for its dye decolorization capacity, and used to bio augment the bioreactor while forming the granules from activated sludge. The incorporation of the yeast with the granules was followed by plating and following the yeast within the microbial community. A commonly used textile azo dye was added to the reactor to follow the biodegradation by the bioaugmented aerobic granular sludge and the efficiency of the process in decolorizing the effluent at varying operational parameters was followed to assess if this is a solution for a safer discharge of such effluents.
- Chitosan coatings reinforced with cellulose crystals and oregano essential oil as antimicrobial protection against the microbiological contamination of stone sculpturesPublication . Silva, Nádia C.; Madureira, Ana Raquel; Pintado, Manuela; Moreira, Patrícia R.The proliferation of microorganisms in outdoor stone sculptures and cultural objects can damage the structure and aesthetics of the materials through biodeterioration mechanisms. Biocides and synthetic products are often used to prevent this phenomenon, despite their negative impact on the environment and human health. Less toxic alternatives with reduced environmental impact can be an option for the preventive conservation of stone sculptures to reduce the environmental impact. In this work, chitosan formulations reinforced with two types of cellulose crystals (microcrystalline cellulose (MCC) or cellulose nanocrystals (CNCs)) and with or without citric acid and sodium tripolyphosphate were prepared. The films obtained with these formulations showed low solubility, and those only containing MCC or CNCs had the lowest wettability. The formulation containing 2% (w/v) MCC was selected for further analysis and supplemented with oregano essential oil (OEO) at 1% (v/v) and 2% (v/v), exhibiting low solubility, swelling and wettability when polymerised in film form. Inoculation of the films with Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa and Rhodotorula spp. resulted in total or partial inhibition of their growth, as well as a 60–100% reduction in Penicillium chrysogenum growth, depending on the concentration of OEO. The formulation with 2% (v/v) OEO was applied to samples of granite, marble and limestone, forming a protective, yet irregular coating on their surfaces. The wettability of the stones’ surfaces was reduced without becoming completely water-repellent and the coating did not cause visible colour changes.
- A coleção científica do Museu do ISEP: as pilhas de Grenet e LeclanchéPublication . Cadeco, Guilhermina; Costa, Patrícia; Campos, Bruno B.; Algarra, Manuel; Yuso, M.ª Valle Martínez de; Moreira, Patrícia R.; Silva, Paulo; Vieira, EduardaO Museu do Instituto Superior de Engenharia do Porto (ISEP), criado em 1999, guarda a memória do ensino industrial da segunda metade do século XIX. Um ensino muito direcionado para a prática do conhecimento que recorria a modelos e instrumentos como metodologia. O acervo museológico é constituído por três grandes coleções: objetos, estampas/desenhos e fotografias, num total de 10 mil peças, aproximadamente. A complexidade desta coleção devido à sua variedade tipológica, gera desafios vários de gestão e conservação. De momento, a principal preocupação centra-se nos objetos porque, para além de serem o maior núcleo da coleção, representam a parcela que ainda não sofreu intervenção especializada, como aconteceu com o Arquivo Histórico. A exemplo disto, as pilhas de Grenet e de Leclanché são dois casos de estudo que demonstram a necessidade proeminente de serem intervencionadas. Este artigo apresenta uma contextualização histórica das pilhas, a sua composição e o estado de conservação dos seus materiais constituintes. Os resultados obtidos servirão para determinar as futuras abordagens de conservação e restauro.
- Contributions to the molecular characterisation of versatile peroxidase from a novel Bjerkandera strainPublication . Moreira, Patrícia R.; Duez, C.; Antunes, A.; Almeida-Vara, E.; Frère, J. M.; Malcata, F. Xavier; Duarte, J. Cardoso
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