MEASUREMENTS OF METAL CONCENTRATION IN AEROSOLS BY LASER-INDUCED BREAKDOWN SPECTROSCOPY (LIBS) TECHNIQUE

L’analisi dei metalli pesanti ha grande importanza all’interno della comunità scientifica a causa del loro impatto sulla salute e sull’ambiente, nonché in ambito di economia circolare. Un uso efficiente delle risorse, il riciclo dei rifiuti e il monitoraggio delle emissioni a camino di termovalorizzatori sono questioni importanti da considerare. La normativa di riferimento sulle emissioni di metalli è la EN14385:2004, in cui sono definiti i limiti di emissione a inceneritore di As, Cd, Cr, Co, Cu, Mn, Ni, Pb, Sb, Tl e V. Per monitorare e valutare la concentrazione in emissione di tali elementi è importante un’analisi in loco e in continuo, e la tecnica Laser Induced Breakdown Spectroscopy (LIBS) è promettente per questo scopo, dato che non necessita la preparazione del campione, a differenza di altre tecniche come ICP e TXRF. La tecnica consiste nel focalizzare un opportuno fascio laser producendo un micro-plasma; le specie presenti all’interno del volume di misura vengono vaporizzate ed eccitate. Il segnale LIBS è il risultato dalla radiazione emessa dalla diseccitazione di queste specie. Lo scopo del lavoro di tesi di questo PhD, finanziato da TCR Tecora s.r.l. e dal Consiglio Nazionale delle Ricerche (CNR) all’interno di un progetto Europeo di innovazione (ROP ERDF 2014 – 2020 - F.A.N.G.H.I), è lo studio della tecnica LIBS per sviluppare un prototipo strumentale per condurre misure online di concentrazione di metalli pesanti all’emissione. È stato sviluppato un apparato sperimentale da laboratorio per misure LIBS su aerosol, successivamente ottimizzato per l’acquisizione del segnale e la seguente analisi. La scelta opportuna dei parametri di raccolta del segnale (ritardo di acquisizione rispetto all’impulso laser e tempo di integrazione del segnale) è importante nella prospettiva di discriminare le linee di emissione atomica rispetto alla radiazione continua di fondo. Le migliori condizioni sperimentali sono state valutate per migliorare la sensibilità del segnale e un appropriato programma di analisi è stato sviluppato in Matlab per l’analisi. In questo contesto, è stato eseguito ed ampiamente discusso un interessante studio sull’effetto matrice dovuto alla presenza di gas o di differenti analiti all’interno del volume di misura. L’apparato sperimentale da laboratorio è stato riassemblato in una configurazione trasportabile, ottenendo un prototipo adatto alle misure a campo. In queste condizioni sono state costruite le curve di calibrazione degli elementi di interesse e i limiti di rivelabilità ottenuti sono stati descritti e comparati con i dati presenti in letteratura. Inoltre, con l’obiettivo di ridurre i limiti di rivelabilità, è stato raccolto l’aerosol su filtro per eseguire misure direttamente sul deposito. A tal fine, sono state eseguite delle opportune modifiche al prototipo tanto quanto alle condizioni di acquisizione del segnale, per renderle adatte alle analisi su filtro. Sono state costruite le corrispondenti curve di calibrazione e sono stati valutati i limiti di rivelabilità. Infine, sono stati presentati differenti casi studio. Sono stati analizzati dei filtri carichi di sedimenti raccolti sulla superficie nevosa della Cordillera Blanca. Questi campioni all’apparenza rossastri, come dimostrato dalle misure LIBS, erano carichi di ferro ossidato, di cui grazie alla calibrazione è stato possibile valutarne la concentrazione superficiale. Infine, è stato condotto uno studio qualitativo e quantitativo su polveri provenienti dal consumo di freni fornite da TCR Tecora. Le analisi su queste polveri hanno permesso di valutare il contenuto di alcuni metalli. Gli esempi riportati hanno lo scopo di sottolineare il potenziale della tecnica in diverse applicazioni. Inoltre, il lavoro complessivo condotto durante il periodo di PhD ha raggiunto uno stato di avanzamento con risultati significativi che sono alla base per analisi future su questo tema.Heavy metals analysis is of great interest to the scientific community for its impact on human health and the environment, as well as in the framework of circular economy. An efficient use of resources, recycling waste, and emissions monitoring in waste-to-energy plants are challenging issues to be considered. The reference standard on metal emissions is EN14385:2004, which defines the incinerator emission limits of As, Cd, Cr, Co, Cu, Mn, Ni, Pb, Sb, Tl, and V. In-situ and continuous analysis are important to monitor and evaluate emission concentrations of these metals, Laser Induced Breakdown Spectroscopy (LIBS) technique is promising for this purpose, since no sample preparation is needed compared to other standard techniques, such as ICP or TXRF. The technique consists of focusing an appropriate laser beam producing a microplasma; the species present in the probe volume are vaporised and excited. LIBS signal results from the radiation emitted by the de-excitation of these species. The aim of this Industrial PhD thesis, financed by TRC-TECORA s.r.l. and the National Council of Research (CNR) within a European project of innovation (ROP ERDF 2014 – 2020 - F.A.N.G.H.I), is the study of the LIBS technique to develop an instrumental prototype to carry out qualitative and quantitative metals emission concentration measurements. An experimental laboratory apparatus for LIBS measurements on aerosol has been developed and optimized for signal acquisition and processing. In fact, a proper choice of the detection parameters (delay with respect to the laser pulse and integration time of the detector gate) is important in the perspective of discriminating the emission atomic lines with respect to the background continuum emission. The best experimental conditions have been tested to increase signal sensitivity and a suitable processing Matlab software has been developed for signal analysis. In this context, an interesting study on matrix effects due to gas species and /or concomitant presence of different analytes in the probe volume is also performed and widely described. The laboratory experimental arrangement has been reassembled in a portable configuration, obtaining a suitable prototype for field measurements. In these conditions, calibration curves of the elements under analysis have been built up, and the results concerning the limit of detection are presented and compared with literature data. Moreover, to improve the detection limits, an accumulation of aerosol particles on filters was performed for LIBS measurements directly on particles-loaded filters. To this purpose, proper changes in the prototype apparatus have been built as well as in the experimental detection conditions, resulting more suitable for filter analysis. The corresponding calibration curves have been performed and the limit of detection retrieved. Finally, different case studies are presented. Particles-loaded filters obtained from snow superficial sediments of Cordillera Blanca are investigated. These samples exhibited a reddish colour, which was proved to be due to iron oxide thanks to LIBS measurements. Iron was then quantified thanks to a proper calibration. In the end, a qualitative and quantitative study was carried out on brakes powder supplied by TCR-TECORA in the framework of a field campaign on brakes analysis. LIBS measurements on these powders allow us to evaluate the presence of metals in the powder. The examples reported are particular and aimed to underline the potential of the technique in different applications. Furthermore, the overall work performed during this PhD period has reached a stage of advancement with significant results that will be the basis of future investigations on this topic

Oxidative damage and cell-programmed death induced in Zea mays L. by allelochemical stress

The allelochemical stress on Zea mays was analyzed by using walnut husk washing waters (WHWW), a by-product of Juglans regia post-harvest process, which possesses strong allelopathic potential and phytotoxic effects. Oxidative damage and cell-programmed death were induced by WHWW in roots of maize seedlings. Treatment induced ROS burst, with excess of H2O2 content. Enzymatic activities of catalase were strongly increased during the first hours of exposure. The excess in malonildialdehyde following exposure to WHWW confirmed that oxidative stress severely damaged maize roots. Membrane alteration caused a decrease in NADPH oxidase activity along with DNA damage as confirmed by DNA laddering. The DNA instability was also assessed through sequence-related amplified polymorphism assay, thus suggesting the danger of walnut processing by-product and focusing the attention on the necessity of an efficient treatment of WHWW

CARACTERIZAÇÃO DAS AÇÕES DE SEGURANÇA ALIMENTAR E NUTRICIONAL EM INDIVÍDUOS COM HIV: UMA REVISÃO INTEGRATIVA

CARACTERIZAÇÃO DAS AÇÕES DE SEGURANÇA ALIMENTAR E NUTRICIONAL EM INDIVÍDUOS COM HIV: UMA REVISÃO INTEGRATIV

Estimativa de oferta de vitamina D em Programas dirigidos à população HIV/AIDS

Nesse momento com a maior atenção dos serviços de saúde direcionada a atender a demanda criada pela COVID-19, há uma preocupação pelo impacto que a atual pandemia pode causar nessa população, principalmente deficiência de vitaminas e minerais. Com isso, o intuito desse trabalho foi identificar o conteúdo de vitaminas D nos Programas que envolvem distribuição de alimentos e analisar a oferta desta vitamina e o nível de adequação à RDA para esse grupo populacional. Foi conduzida uma busca de estudos nas bases de dados da Medline/Pubmed, Web of Science, Scopus, Embase, Lilacs, Livivo e Open Grey. Dos 259 resumos identificados, apenas 12 estudos selecionados para a extração de dados, no qual foram expostos em figuras de acordo com a caracterização, distribuição de indicadores usados e estimativa de colecalciferol nos alimentos distribuídos. Esse estudo reforça a importância das ações de Segurança Alimentar e Nutricional, além disso, sugere a incorporação de marcadores específicos do status nutricional de vitamina D em futuros Programas destinados a PVHIV visto a importância desta vitamina nesses indivíduos

Pure apraxia of speech due to infarct in premotor cortex

Apraxia of speech (AOS) is now recognized as an articulation disorder distinct from dysarthria and aphasia. Various lesions have been associated with AOS in studies that are limited in precise localization due to variability in size and type of pathology. We present a case of pure AOS in setting of an acute stroke to localize more precisely than ever before the brain area responsible for AOS, dorsal premotor cortex (dPMC). The dPMC is in unique position to plan and coordinate speech production by virtue of its connection with nearby motor cortex harboring corticobulbar tract, supplementary motor area, inferior frontal operculum, and temporo-parietal area via the dorsal stream of dual-stream model of speech processing. The role of dPMC is further supported as part of dorsal stream in the dual-stream model of speech processing as well as controller in the hierarchical state feedback control model

The algal diversity in the Phlegrean Fields (Campania, Italy) archeological districts: an overview

The coexistence of several ecological conditions (hot springs, streams, mud, rock walls), characterized by different pH, temperature values, water potential and mineralogical makes the Phlegrean Fields as an ideal area for the analysis of the microalgal assemblages and their relationships with the different microhabitats occurring in the sites. Here we report an overview of the algal diversity within the archaeological and geothermal areas of Phlegrean Fields and the adaptability for most of them to acidic and thermal conditions in the volcanic soils

The algal diversity in the Phlegrean Fields (Campania, Italy) archeological districts: an overview

The coexistence of several ecological conditions (hot springs, streams, mud, rock walls), characterized by different pH, temperature values, water potential and mineralogical makes the Phlegrean Fields as an ideal area for the analysis of the microalgal assemblages and their relationships with the different microhabitats occurring in the sites. Here we report an overview of the algal diversity within the archaeological and geothermal areas of Phlegrean Fields and the adaptability for most of them to acidic and thermal conditions in the volcanic soils

Cyanidiophyceae in Iceland: Plastid rbcL gene elucidates origin and dispersal of extremophilic Galdieria sulphuraria and G. maxima (Galdieriaceae, Rhodophyta)

The Cyanidiophyceae are a group of unicellular organisms that diverged from ancestral red algae around 1.3 billion years ago. Present-day species are restricted to hot springs and geothermal habitats from around the world. Because of discontinuous geothermal environments, the distribution patterns and dispersal modes of the cyanidiophycean species are poorly understood. Iceland is the third largest island in the Atlantic Ocean and has intense underground volcanic activity that generates broad hydrothermal areas with different ecological conditions that are excellent for thermoacidophilic microfloral development. We analyzed populations to address the Icelandic cyanidiophycean biodiversity and dispersal. A global rbcL phylogeny showed two main populations inhabiting Iceland, Galdieria sulphuraria and G. maxima. Their areas of distribution are not completely superimposed because they coexisted only in New Zealand, Kamchatka (Russia), Japan, and Iceland. Because of the strong monophyly of Icelandic species with Japanese and Russian species, we hypothesized an origin and dispersion of Icelandic G. suphuraria and G. maxima from northeastern Asia. On the basis of network analysis of rbcL haplotypes, it is likely that the southwestern region of Iceland is the diversity center of both G. sulphuraria and G. maxima

Cyanidium chilense (Cyanidiophyceae, Rhodophyta) from tuff rocks of the archeological site of Cuma, Italy

Phlegrean Fields is a large volcanic area situated southwest of Naples (Italy), including both cave and thermoacidic habitats. These extreme environments host the genus Cyanidium; the species C. chilense represents a common phototrophic micro- organism living in anthropogenic caves. With a view to provide a comprehensive characterization for a correct taxonomic classification, morpho-ultrastructural investigations ofC. chilense from Syb’s cave (Phlegren Fields) was herein car-ried out and compared with the thermoacidophilic C. caldarium. The biofilm was also analyzed to define the roleofC. chilensein the establishment of a bio film within caveenvironments. Despite the peculiar ecological and molecular divergences,C. chilenseandC. caldariumshared all the maindiacritic features, suggesting morphological convergence within the genus; cytological identity was found amongC. chilensestrains geographically distant and adapted to different substrates, such as the porous yellow tuff of Sybil cave and calcyte, magnesite and basaltic rocks from other caves. C. chilense is generally dominant in all biofilms, developing monospecific islets, developing both super ficially or betweenfungal hyphae and coccoid cyanobacteria. Extracellular polymeric substances (EPS) were recorded in C. chilense bio filmsfrom Sybil cave, confirming the role of EPS in facilitating cellsadhesion to the surface, creating a cohesive network of inter-connecting biofilm cell