Cu- and Za-soil anomalies in the NE border of the South Portuguese Zone (Iberian Variscides, Portugal). Identified by multifractal and geostatistical analysis

Extensive Cu- and Zn-soil geochemical data in the Albernoa/Entradas–S. Domingos region (NE border of the Iberian Pyrite Belt, South Portuguese Zone) were examined to separate anomalies from background using the concentration–area fractal model. Distribution patterns of Cu and Zn concentrations in soil are primarily influenced by bedrock. The regional threshold values of Cu- and Zn-soil contents over metasedimentary sequences are 20–25 and 20–60 ppm, respectively, becoming 30–50 and 20–90 ppm, respectively, when metavolcanic rocks are present. The first-order threshold values for Cu are 80–90 ppm in soils over metasediments and 70–80 ppm in soils over sequences bearing metavolcanics. For Zn, the first-order threshold values are 40–80 and 90–100 ppm in soils over metasediments and metavolcanic rocks, respectively. Metasediments and metavolcanics comprising significant sulphide disseminations are outlined by Cu- and Zn-soil values above 100 and 300 ppm in soil, respectively. On the basis of these results, Alvares and Albernoa/Entradas areas emerge as the first priority targets for exploration. The observed non-coincidence of Cu- and Zn-soil anomalies in soil in the area could reflect difference in element dispersion during weathering, they mostly indicate distinct metal sources related to the original composition of different rock types or to chemical changes developed during Variscan deformation/re-crystallization path. The established regional baseline data can be used as reference for environmental studies

Geochemistry of stream sediments southwards of the SW Variscan suture in Portugal (Guadiana and Chança river basins) : insights into element anomalies of variable origin and intensity

Stream sediment samples were collected in the Trindade–Chança region at 1034 sites for mineral exploration purposes during 1996–97. Concentrations of Cu, Zn, Pb, Co, Cr and Ni are high enough in most sample sites to allow data assessment by multi-element anomaly definition and threshold computation using the area concentration multifractal model technique. The regional threshold values are 20, 45, 30 and 15 ppm for Cu, Zn, Pb and Co respectively. Anomalies for Cu, Zn, Pb, Co, Cr and Ni are delimited by first order local threshold values at 40, 94, 70, 21, 37 and 42 ppm. The main anomalies are clustered to the east-southeast of the surveyed region and reflect mixed contributions from a variety of sources, namely different volcanic units with local contributions from pelite rocks, contamination from old (abandoned) mining activities and hydrothermal mineralisation controlled by different fault zones

The Potential of Unsaturated Polyesters in Biomedicine and Tissue Engineering: Synthesis, Structure-Properties Relationships and Additive Manufacturing

The success of Tissue Engineering (TE) based approaches is strongly dependent on the development of novel biomaterials for the design of 3D matrices with tailored biomechanical properties to promote the regeneration of human tissues and organs.This review covers the critical aspects related with the preparation of new unsaturated polyester (UP) resin formulations with suitable biological, chemical, thermal and morphological properties for the additive manufacturing (AM) of TE constructs. In this context, the basic principles of available AM technologies, with a special focus on novel stereolithography processes such as microstereolithography (micro-SLA), stereo-thermal-lithography (STLA), two-photon polymerization (TPP) and nanostereolithography (nano-SLA), are also presented and discussed. Ultimately, the present review will provide a better insight into the limitations and potential of combining UP and AM towards the rationale design/fabrication of complex artificial tissue substitute

Dynamic aspects of oral processing of curcumin-loaded solid lipid nanoparticles yoghurts by rheology and soft tribology assessment

Mouthfeel and consistency originating from the consumption of yoghurts represent decisive factors for the consumers’ acceptability. The present work aims to identify potential differences in the sensory perceptions of yoghurts with curcumin-loaded solid lipid nanoparticles (SLN) incorporation. Thus, rheology coupled with tribology were considered to simulate the dynamic aspects of oral processing. Similar values for the elastic (G’) and viscous (G’’) parameters were obtained for both control yoghurt and yoghurt with curcuminloaded SLN, as well as flow index (n) and consistency index (k) around 0.56 and 1.50 Pa.sn, respectively. However, the friction behaviour was characterised by significant differences in all tribological regimes, suggesting that the incorporation of nanoparticles in yoghurts could potentially affect the after-feel upon swallowing, whilst not directly impacting on yoghurt’s structure

Prospeção geoquímica e avaliação do impacto ambiental no setor português da Faixa Piritosa Ibérica

ABSTRACT: This work intends to briefly report the history and application of geochemical exploration techniques in the Iberian Pyrite Belt (IPB). The use of geochemistry in IPB for exploration purposes started in 1950’s. Together with geophysics, the soil geochemical exploration surveys performed over several decades were responsible for important discoveries such as Carrasco and Feitais ore-bodies. However, the continuous development of analytical methods and the progress in data processing/modelling led to significant changes in the planning of sampling surveys, and their specific objectives, as well as in the accuracy of geochemical anomalies definition and corresponding interpretation. As a consequence, the number of samples involved in each survey was significantly reduced, but the chemical elements analysed with improved detection limits were considerably extended; additionally, geochemical anomalies were better resolved. Notwithstanding this evolution, data obtained in early soil geochemical surveys (notably by the Serviço de Fomento Mineiro) are still useful in the development of preliminary approaches at a regional scale. Over the years, many studies were made for exploration and environmental assessments, the most relevant of them reported in this chapter. Natural distributions of chemical elements were also identified in these studies as background (if pristine conditions are present) or baseline (depending how disturbed is the area covered by the sampling survey) values. Large part of IPB was, and still is, subjected to poly-metallic mineral exploration or mining, being also the focus of environmental evaluation and/or remediation projects on particular areas that, being the target of long-lasting human intervention, represent paradigmatic case-study examples. The exploration and exploitation works carried out by national and foreign private companies were, and still are, very important for innovative achievements in IPB along with copious contributions from the Portuguese R&D public institutions. Presently, LNEG possesses a vast quantity of geochemical data that can be provided for companies that wish to start their activity in the IPB; some of these datasets are compiled to a unique integrative map also presented in this work. Stream-sediments geochemistry, hydrogeochemistry and lithogeochemistry (of outcropping rock and drill-core samples) represent also important sources of geochemical data in regional or detailed studies over specific target areas in the IPB. However, these techniques are beyond the scope of the present paper which aimed at providing a general overview of the importance of soil geochemistry studies in the current knowledge of the IPB.RESUMO: A geoquímica é aqui abordada através da história da sua utilização na Faixa Piritosa Ibérica (FPI) e correspondente influência na evolução do conhecimento sobre os recursos minerais, distribuição natural dos elementos químicos e avaliação ambiental desta importante província metalogenética. Ao longo do tempo usaram-se na FPI técnicas analíticas cada vez mais precisas para determinar a concentração de um número crescente de elementos químicos. As campanhas de prospecção geoquímica tornaram-se assim progressivamente mais dispendiosas, levando à redução do número de amostras colhidas e analisadas em cada expedição. Consequentemente, no início da década de 1990, foi abandonado o uso de redes densas de amostragem de solos, muitas vezes elaboradas segundo uma esquadria retangular, como prática de rotina em campanhas de prospeção estratégica e tática, desenvolvidas pelos serviços do Estado vocacionados para este tipo de estudos, nomeadamente o Serviço de Fomento Mineiro (SFM). Reconhece-se, no entanto, que mesmo com um número reduzido de elementos químicos e baixa resolução analítica, a elevada densidade de amostragem combinada com diversas técnicas de geofísica desempenhou papel crucial na descoberta de jazigos de sulfuretos maciços na FPI, como são exemplo as massas Carrasco e Feitais em Aljustrel. Presentemente, as atividades de prospeção são maioritariamente desenvolvidas por empresas mineiras com contratos de pesquisa outorgados pelo Estado Português. O Laboratório Nacional de Energia e Geologia (LNEG) é o atual depositário de uma vasta informação de estudos geoquímicos, com destaque para um grande volume de dados produzido pelo SFM e por empresas. As bases de dados do LNEG são frequentemente requisitadas para efeitos de reavaliação de setores estratégicos da província e, em alguns casos, para reprocessamento de dados e reanálise de amostras físicas existentes em arquivo. Estudos geoquímicos desenvolvidos em áreas específicas da FPI são apresentados sumariamente neste artigo, abordando a importância do mapeamento geostatístico multivariado e multifractal de dados de geoquímica, para além de contribuir para a definição dos fundos (concentrações) naturais dos elementos metálicos com interesse económico; isto é, procurando identificar critérios objetivos úteis à separação entre o fundo geoquímico, o nível de referência e a anomalia. Todos estes estudos revelam que as formações constituintes do Complexo Vulcano Sedimentar (CVS - Devónico Superior – Carbónico Inferior) são fontes de metais como o Cu, Zn e Pb, podendo haver ainda alguma contribuição das sequências de metassedimentos pertencentes ao Grupo Filito-Quartzítico (Devónico Médio - Devónico Superior) e ao Grupo do Chança (Devónico Superior). Após um período de intensa prospeção e pesquisa mineral até finais dos anos 90 seguiu-se cerca de uma década e meia de abrandamento desta atividade na Europa, a qual foi, na FPI, gradualmente substituída por estudos de diagnóstico ambiental, procurando responder a novas inquietações sociais e políticas. Alguns desses estudos são também abordados de forma sumária neste capítulo, salientando os que contribuíram para a identificação e caracterização dos principais centros mineiros da FPI, geradores de grande volume de resíduos mineiros e importante drenagem ácida. Salientam-se ainda os sítios da província onde a atividade mineira decorreu por longo período de tempo (ex. S. Domingos, Aljustrel, Lousal e Caveira), em épocas em que o impacto ambiental não fazia parte das preocupações sociais, políticas e económicas das empresas mineiras e das entidades reguladoras. Nestes mesmos locais, e muito recentemente, como resposta à necessidade conjunta de tratamento/valorização de resíduos e salvaguarda da segurança de abastecimento de matérias-primas minerais na Europa (reduzindo a sua dependência externa e fomentando o seu crescimento económico), outros estudos geoquímicos têm vindo a ser realizados. Estes visam a identificação de novas oportunidades e mercados para os resíduos mineiros históricos, considerando-os como recursos secundários de matéria-prima que, por vezes, contêm quantidades acessórias de metais escassos e valiosos, alguns especialmente importantes na manufactura de componentes da “alta tecnologia”. A prospecção geoquímica não se restringe à geoquímica de solos, muito embora o presente artigo lhe seja inteiramente dedicado por a mesma representar uma abordagem geral dos trabalhos desenvolvidos na FPI, ao longo de mais de meio século.info:eu-repo/semantics/publishedVersio

Green synthesis of lignin nano- and micro-particles: Physicochemical characterization, bioactive properties and cytotoxicity assessment

Lignin particles (LPs) have gained prominence due to their biodegradability and bioactive properties. LP production at nano and micro scale produced from organosolv lignin and the understanding of size's effect on their properties is unexplored. This work aimed to produce and characterize lignin nanoparticles and microparticles using a green synthesis process, based on ethanol-solubilized lignin and water. Spherical shape LPs, with a mean size of 75 nm and 215 nm and with a low polydispersity were produced, as confirmed by transmission electron microscopy and dynamic light scattering. LPs thermal stability improved over raw lignin, and the chemical structure of lignin was not affected by the production method. The antimicrobial tests proved that LPs presented a bacteriostatic effect on Escherichiacoli and Salmonella enterica. Regarding the antioxidant potential, LPs had a good antioxidant activity that increased with the reaction time and LPs concentration. LPs also presented an antioxidant effect against intracellular ROS, reducing the intracellular ROS levels significantly. Furthermore, the LPs showed a low cytotoxic effect in Caco-2 cell line. These results showed that LPs at different scales (nano and micro) present biological properties and are safe to be used in different high value industrial sectors, such as biomedical, pharmaceutical and food.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2020 unit, BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte, and MICRODIGEST project (grant agreement 037716) co-funded by FCT and ERDF through COMPETE2020.info:eu-repo/semantics/publishedVersio

β-ketoenamine covalent organic frameworks—effects of functionalization on pollutant adsorption

Water pollution due to global economic activity is one of the greatest environmental concerns, and many efforts are currently being made toward developing materials capable of selectively and efficiently removing pollutants and contaminants. A series of β-ketoenamine covalent organic frameworks (COFs) have been synthesized, by reacting 1,3,5-triformylphloroglucinol (TFP) with different C2-functionalized and nonfunctionalized diamines, in order to evaluate the influence of wall functionalization and pore size on the adsorption capacity toward dye and heavy metal pollutants. The obtained COFs were characterized by different techniques. The adsorption of methylene blue (MB), which was used as a model for the adsorption of pharmaceuticals and dyes, was initially evaluated. Adsorption studies showed that –NO2 and –SO3H functional groups were favorable for MB adsorption, with TpBd(SO3H)2-COF [100%], prepared between TFP and 4,4′-diamine- [1,1′-biphenyl]-2,2′-disulfonic acid, achieving the highest adsorption capacity (166 ± 13 mg g−1). The adsorption of anionic pollutants was less effective and decreased, in general, with the increase in –SO3H and –NO2 group content. The effect of ionic interactions on the COF performance was further assessed by carrying out adsorption experiments involving metal ions. Isotherms showed that nonfunctionalized and functionalized COFs were better described by the Langmuir and Freundlich sorption models, respectively, confirming the influence of functionalization on surface heterogeneity. Sorption kinetics experiments were better adjusted according to a second-order rate equation, confirming the existence of surface chemical interactions in the adsorption process. These results confirm the influence of selective COF functionalization on adsorption processes and the role of functional groups on the adsorption selectivity, thus clearly demonstrating the potential of this new class of materials in the efficient and selective capture and removal of pollutants in aqueous solutions.This work was funded by the Coimbra Chemistry Centre (CQC), which is supported by the Fundação para a Ciência e a Tecnologia (FCT), Portugal, through the grants ref. UID/QUI/00313/2020 and ref. UI/BD/150809/2020, co-funded by COMPETE2020-UE

In vitro digestion and bioaccessibility studies of vitamin E-loaded nanohydroxyapatite pickering emulsions and derived fortified foods

Vitamin E is a lipophilic vitamin playing an essential role in human health. Due to oxidative instability, it presents fast degradation and bioactivity loss. In this study, vitamin E-loaded Pickering emulsions stabilized by nano-hydroxyapatite (n-HAp) were produced using a static mixer (NETmix), a technique enabling continuous production and droplet size tailoring. Thus, oil-in-water (O/W) emulsions containing vitamin E at a content of 1mg/mL were produced with different droplet sizes (7.53, 11.56 and 17.72m) using an O/W ratio of 20/80 (v/v). Their stability during in vitro gastrointestinal digestion and vitamin E bioaccessibility were investigated. It was observed that n-HAp particles disrupt in the stomach and subsequently aggregate as random calcium phosphates in the small intestine, leading to low vitamin E bioaccessibility due to oil entrapment. The emulsion showing the highest vitamin E bioaccessibility (3.29±0.57%, sample with the larger average droplet size) was used to produce fortified gelatine and milk, resulting in an increased bioaccessibility (10.87±1.04% and 18.07±2.90%, respectively). This fact was associated with the presence of macronutrients and the lower n-HAp content. Overall, n-HAp Pickering emulsions offer advantages for vitamin E encapsulation directed to fortified foods development, a process able to be extended to other lipophilic vitamins.This work was financially supported by Base Funding -UIDB/50020/2020 of the Associate Laboratory LSRE-LCM -funded by national funds through FCT/MCTES (PIDDAC), Base Funding -UIDB/00690/2020 of CIMO -funded by national funds through FCT/MCTES (PIDDAC), and Base Funding -UIDB/04469/2020 of the CEB funded by national funds through FCT. Andreia Ribeiro acknowledges her PhD fellowship funded by Project NORTE-08-5369-FSE-000028, supported by N2020, under PT2020, through ESF, and Raquel F. Goncalves acknowledges the Foundation for Science and Technology (FCT) for their fellowship (SFRH/BD/140182/2018). Authors thank Fluidinova S.A. for providing samples of nanoXIM-CarePaste and Instituto de Investigacao e Inovacao em Saude (i3S) for the services provided with CLSM analysis.info:eu-repo/semantics/publishedVersio