Modern Metals in Cultural Heritage, understanding and characterization

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Looking into historical cracks analysing repaired silver objects by electron microscopy

ABSTRACT: The identification of structural alterations of silver alloy objects of cultural interest is essential to assess their state of conservation and define maintenance programmes. Alterations induced by previous repair and cleaning actions strongly affect the conservation condition, influencing the type and extension of conservation procedures. The detailed analysis of ancient repairs is a subject to be investigated. In this work, we show the potentialities of scanning electron microscopy in the characterisation of structural repairs and their influence on the conservation state of silver objects. The study of distinct silver objects dated to the 16th and 18th centuries allowed us to show, among others, the non-intentional dealloying of copper due to the use of acid solutions in surface cleanings and cracks resulting from incorrect handling. The data collected by microscopic examination contributed to the definition of preservation and maintenance methodologies applied to those silver objects.info:eu-repo/semantics/publishedVersio

Discovering the colours of industrial heritage characterisation of paint coatings from the powerplant at the Levada de Tomar

The paint coatings of three energy generators from the 20th-century powerplant at Levada de Tomar, Portugal, were investigated using micro-Raman and micro-X-ray fluorescence spectroscopies and scanning electron microscopy with energy dispersive spectroscopy. This multi-analytical approach was used to identify the colouring agents, thus providing a chronological chromatic pallet and allowing to infer on the use of the three energy generators. Together with traditional pigments like Prussian blue, red iron oxide, and carbon black, pigments used in industrial areas like copper phthalocyanine and toluidine red were identified as colouring agents. Complex paint systems of the oldest equipment (1924) were revealed as well as maintenance procedures of the equipment that worked during a longer time (1944–1990). Powdery carbon black layers, resulting from incomplete hydrocarbon combustion and present between metallic substrates and coating layers, suggested the inexistence of paint coatings replacement after the powerplant shutdown. The identification of magnetite as a corrosion product of iron alloy substrate revealed that corrosion developed after the engine shutdown and not during the operation period. The results obtained highlight the potentialities of scientific-based approach and Raman spectroscopy to the industrial heritage study, an emergent cultural area.publishersversionpublishe

WORKING TOGETHER Conservation and safeguarding of industrial and technological heritage

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Reflections on the conservation challenges of scientific and technological objects

PTDC/FIS-AQM/30292/2017The conservation of science and technology (S&T) heritage encompasses complex challenges. Among the reasons for this complexity are the S&T objects specific characteristics: the wide variety of materials, construction techniques and dimensions, and the existence of operating mechanisms. Present conservation methods are not fully adapted to the specificity of this heritage, requiring more research on S&T conservation. This paper identifies the main challenges of S&T objects conservation and gives guidelines to overcome them by i) increasing knowledge on materials and their degradation; ii) understanding the objects' function; iii) researching and developing new conservation techniques compatible with the characteristics of S&T objects; and iv) creating decision-making tools for the definition and implementation of conservation and maintenance programs.publishersversionpublishe

Cultura Material, Cultura Científica: Património Industrial para o Futuro

IH4Future (PTDC/FIS-aQM/30292/2017Material, Culture, Scientific Culture: Industrial Heritage for the Futurepublishersversionpublishe

Effects of gamma radiation on chemical and antioxidant properties, anti-hepatocellular carcinoma activity and hepatotoxicity of borututu

Borututu is a well-known medicinal plant in Angola for the treatment of liver diseases and for the prophylaxis of malaria. Our research group reported, in a recent study, that its infusion, pills and syrups display significant antioxidant and anti-hepatocellular carcinoma activities. However, during the processing and storage, it can be easily exposed to contamination that can lead to a microbial deterioration or insect infestation compromising its quality, shelf life, and efficiency. Herein, we investigated the effect of gamma irradiation, one of the most promising decontamination methods for many foodstuffs and plant materials, at different doses (1 and 10 kGy) on borututu regarding its nutritional value, lipophilic (fatty acids and tocopherols) and hydrophilic (free sugars and organic acids) compounds, antioxidant and anti-hepatocellular carcinoma activities. In general, the irradiation treatment did not appreciably affect the nutritional value of the studied plant, but the highest energetic contribution (383.83 kcal/100 g), total sugars (8.63 g/100 g), organic acids (3.31 g/100 g dw), total tocopherols (336.72 mg/100 g dw), and PUFA (32.75%) contents were found in the sample irradiated at 10 kGy. Furthermore, this sample presented also the highest levels of total phenolics and flavonoids and, in general, the highest antioxidant activity (EC50 values of 0.04 to 0.24 mg/mL for the methanolic extract and 0.03 to 1.34 mg/mL for the infusion). Irradiated samples kept the anti-hepatocellular carcinoma activity, but a decrease was observed in the methanolic extract prepared from sample irradiated at 10 kGy (GI50 = 188.97 μg/mL). Overall, gamma irradiation proved to be a suitable technique of preservation of dried herbs without affecting the bioactive compounds

Epidemiology of invasive candidiasis in a surgical intensive care unit: an observational study

Background: Invasive candidiasis (IC) is a frequent and life-threatening infection in critically ill patients. The aim of this study was to evaluate the epidemiology of IC and the antifungal susceptibility of etiological agents in patients admitted to our surgical intensive care unit (SICU) in Spain. Methods: We designed a prospective, observational, single center, population-based study in a SICU. We included all consecutive adult patients (≥18 years old) who had documented IC, either on admission or during their stay, between January 2012 and December 2013. Results: There were a total of 22 episodes of IC in the 1149 patients admitted during the 24-month study. The overall IC incidence was 19.1 cases per 1000 admissions. Thirteen cases of IC (59.1 %) were intra-abdominal candidiasis (IAC) and 9 (40.9 %) were candidemias. All cases of IAC were patients with secondary peritonitis and severe sepsis or septic shock. The overall crude mortality rate was 13.6 %; while, it was 33 % in patients with candidemia. All patients with IAC survived, including one patient with concomitant candidemia. The most common species causing IC was Candida albicans (13; 59.1 %) followed by Candida parapsilosis (5; 22.7 %), and Candida glabrata (2; 9.1 %). There was also one case each (4.5 %) of Candida krusei and Candida tropicalis. Thus, the ratio of non-C. albicans (9) to C. albicans (13) was 1:1.4. There was resistance to fluconazole and itraconazole in 13.6 % of cases. Resistance to other antifungals was uncommon. Conclusions: Candida parapsilosis was the second most common species after C. albicans, indicating the high prevalence of non-C. albicans species in the SICU. Resistance to azoles, particularly fluconazole, should be considered when starting an empirical treatment. Although IAC is a very frequent form of IC in critically ill surgical patients, prompt antifungal therapy and adequate source control appears to lead to a good outcome. However, our results are closely related to our ICU and any generalization must be taken with caution. Therefore, further investigations are needed. Keywords: Intensive care unit, Invasive candidiasis, Candidemia, Antifungal susceptibilit

The jewellery of René Lalique: technology vs. atmospheric corrosion

International audienc

Corrosão e conservação de objectos em liga de ouro

International audienc