Application of laser-induced breakdown spectroscopy (libs) in industrial processes and archaeology

RESUMEN: La espectroscopía de ablación inducida por láser (LIBS) es una técnica de análisis elemental basada en la ablación de un material y la formación de un plasma por la acción de un pulso láser de energía alta que interacciona sobre un material objetivo. El análisis mediante espectroscopía de la luz emitida por ese plasma permite la caracterización del material por medio de la identificación de las líneas de emisión características de los elementos que conforman la muestra. En la presente tesis se utiliza la técnica LIBS en dos campos de aplicación distintos. Por un lado, se han analizado los metales adsorbidos en resinas quelantes usadas en gestión de residuos de procesos industriales. Por otro lado, la aplicación de LIBS en ejemplares arqueológicos de moluscos marinos ha permitido establecer una relación entre su composición y la temperatura del agua del mar.ABSTRACT: Laser-induced breakdown spectroscopy (LIBS) is an elemental analysis technique based on the ablation of a small portion of sample material and the formation of plasma by a high-energy laser pulse interacting with a target material. The spectroscopic analysis of the light emitted by this plasma allows the characterization of the material by identifying the characteristic emission lines of the elements present in the sample. In this thesis the LIBS technique is used in two different fields of application. On the one hand, the metals adsorbed on chelating resins used in waste management of industrial processes have been analyzed. On the other hand, the application of LIBS in archaeological specimens of marine mollusks has allowed us to establish a relationship between their composition and the temperature of the sea water

Development of a laser-based analytical platform for the LIBS inspection of individual nanoparticles within an atmospheric pressure optical trap

En esta tesis doctoral se presenta un sensor basado en LIBS como técnica de inspección para la caracterización de nanopartículas individuales. El cuerpo de este trabajo se divide en cuatro capítulos en los que se recoge, en primer lugar, el desarrollo del sensor y la parametrización sistemática de los diferentes factores que influyen en el análisis LIBS (densidad de energía, condiciones de adquisición o la posición partícula-láser de análisis) y a la trampa óptica (rigidez de la trampa, manipulación de la partícula atrapada). Posteriormente, se muestran las capacidades analíticas de la tecnología OC-OT-LIBS propuesta haciendo énfasis en los tamaños y masas mínimas detectables haciendo uso de ella y respondiendo a cuestiones fundamentales como los mecanismos de disociación y excitación que tienen lugar durante la interacción láser-materia a través de los espectros obtenidos. Además, dado que el atrapado óptico en aire a presión atmosférica es aún un terreno poco explorado, se recogen resultados novedosos respecto a las posibilidades ofrecidas por la técnica

Ablative brain surgery : an overview

Background: Ablative therapies have been used for the treatment of neurological disorders for many years. They have been used both for creating therapeutic lesions within dysfunctional brain circuits and to destroy intracranial tumors and space-occupying masses. Despite the introduction of new effective drugs and neuromodulative techniques, which became more popular and subsequently caused brain ablation techniques to fall out favor, recent technological advances have led to the resurgence of lesioning with an improved safety profile. Currently, the four main ablative techniques that are used for ablative brain surgery are radiofrequency thermoablation, stereotactic radiosurgery, laser interstitial thermal therapy and magnetic resonance-guided focused ultrasound thermal ablation. Object: To review the physical principles underlying brain ablative therapies and to describe their use for neurological disorders. Methods: The literature regarding the neurosurgical applications of brain ablative therapies has been reviewed. Results: Ablative treatments have been used for several neurological disorders, including movement disorders, psychiatric disorders, chronic pain, drug-resistant epilepsy and brain tumors. Conclusions: There are several ongoing efforts to use novel ablative therapies directed towards the brain. The recent development of techniques that allow for precise targeting, accurate delivery of thermal doses and real-time visualization of induced tissue damage during the procedure have resulted in novel techniques for cerebral ablation such as magnetic resonance-guided focused ultrasound or laser interstitial thermal therapy. However, older techniques such as radiofrequency thermal ablation or stereotactic radiosurgery still have a pivotal role in the management of a variety of neurological disorders

Rare Earth Elements analysis to identify anthropogenic signatures at Valle del Serpis (Spain) Neolithic settlements

Due to their particular geochemical properties and stability Rare Earth Elements (REE) can act as a ‘fingerprint’ for soils, and as a consequence have been employed in a variety of different archaeological scenarios in order to identify past human activities.In this study, for the first time, we apply REE signatures in different Spanish Neolithic settlements, all located in the Valle del Serpis region. More than 100 Neolithic settlements have been identified in this area, and most of these open sites are characterised by dark brown strata that are in contrast with the light brown soils of the valley. These dark brown deposits are usually covered by paleosols and have been interpreted as markers of anthropogenic activities. However, in order to demonstrate whether these strata are anthropogenic or natural features requires a better understand-ing of soil development processes. A total of fifty samples were taken across six different sites, and from each site the sam-pling was carried out at different depths through 3m deep sections. Four sites are clearly associated with archaeological findings (sites BF, LP, PB and AC); another one is from a natural section near the Neolithic site of Mas d’Is (MD) and has been radiocarbon dated to the beginning of the Holocene (7751-7611 cal BC); and the last corresponds to a place of uncertain attribution (BK). Major, minor and trace elements including REE were determined using XRF and ICP- MS, with Principal Components Analysis (PCA) used to statistically analyze these data. Results were then compared with the strata soil properties analysed by XRD and particle size analysis, and cross-referenced with archaeological data to aid interpretation. The results demonstrate that REE analyses provide significant details regarding anthropogenic activities and strata development history, and in this instance confirm and elaborate on the archaeological interpretation that these dark brown deposits are evidence of a region-wide agricultural system in the Neolithic Valle del Serpis

The source of the building stones from the Sagunto Castle archaeological area and its surroundings

A multidisciplinary study was carried out on the building stones of the masonries belonging to the Castle of Sagunto (Valencia, Spain), an important historical and archeological complex, characterized by several construction phases from the Roman Period to the Modern Ages. For the first time, the stones of the Sagunto Castle have been analysed to determine their chemical, mineralogical and petrographic features, the main physical and mechanical properties, and to understand their decay, use and recycling dynamics in the different building during the entire occupational period. Geochemical and mineralogical analyses employing X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray diffraction (XRD) were carried out together with optical and electronic microscope analysis to observe the stone macro- and micro-structures. The collected data were processed by Principal Component Analysis (PCA) to highlight differences among the studied structures. The results show that the stones employed to build Sagunto`s structures during the different historical periods are related to a specific quarried area located nearby Sagunto Castle hill and differences between the studied samples are mostly related to the conservation state of the buildings. Therefore, geochemical analyses confirm the origin of the raw materials, while petrographic and physical analyses have been useful to evaluate the conservation state of the studied Sagunto Castle structures

Standoff Sensing Technology Based on Laser-Induced Breakdown Spectroscopy: Advanced Targeting, Surveillance and Reconnaissance in Security and Architectural Heritage Applications

Due to the ability to perform simultaneous, multi-element and real-time analysis without pretreatment and doing from a distance, laser induced breakdown spectroscopy (LIBS) in standoff mode is now considered a cutting-edge analytical technology. All these features have allowed its application in various fields such as security, environment, cultural heritage protection and space exploration, among the more outstanding. Nonetheless, the fact of working to long distances involves greater difficulties than in a lab-scale. Thus, in a first part of this memory, the behavior of the analytical signal has been assessed. On the other hand, a second part demonstrates the applicability of the technique in standoff mode for solving real-life problems. • Fundamental studies 1. Main causes affecting the uncertainty of the analytical signal in standoff LIBS. One of the most sensitive issues in standoff LIBS is maybe the large variability observed in the analytical response of distant targets. Therefore, in this work, a standoff LIBS sensor has been used to assessment of the laser beam delivering up to a distant target as well as the properties of the light emitted from the plasma induced gathered by the sensor. • Applications standoff LIBS 1. Evaluation of the Cultural Heritage: Malaga Cathedral. Cultural heritage is a valuable source of history and a unique and irreplaceable legacy of our past. While sometimes an artwork can be transported to the laboratory for its analysis, in other cases this option is not feasible. The ease compaction in mobile platforms of LIBS instrumentation for in situ analysis, allows for moving the system sensor to the location of the sample. For first time a standoff LIBS system has been used to characterize and analyze the composition of building materials as well as potential sources of contamination in a historic building on difficult to access areas, since this technology only requires a clear line of sight to the target. I. Location and identification of explosive-contaminated fingerprint. Nowadays, it is clear that the detection of explosives due to numerous terrorist attacks requires a special attention. LIBS is an attractive technology to anticipating this type of threats. In the present work, the ability of a mobile LIBS sensor to locate and identify fingerprints of explosives residues (DNT, TNT, RDX, PETN and chloratite ) on different surfaces (aluminum and glass) from a minimum distance of 30m has been demonstrated. Chemical distribution maps of the different residues with 100% effectiveness were developed. However, despite the effectiveness of the technique in the localization and detection of explosives residues, one of the main problems is the identification of products that share a similar elemental composition, and thus a similarity in the analytical response. In this memory have been developed and implemented chemometric algorithms, which are capable of adapting to different working ranges, to distinguish residues of organic explosives of traces of dairy products, such as olive oil, motor oil, hand cream, gasoline, fuel oil, etc. on a metal surface (aluminum). This strategy allows categorize the residues assessed with a 100% accuracy and error rates below 5 %. II. Forensic studies for the determination of radiological material. Although radioactivity has numerous applications in everyday life, the danger of a radiological dispersal event, either by natural causes or malicious (dirty bombs) is more than evident. Therefore, the detection and identification of explosives as well as their monitoring and quantification from a safe location is demanded. The potential of standoff LIBS to scan, analyze and quickly characterize the radiological contamination in various objects of street furniture has been here evaluated. The results have demonstrated the selectivity and sensitivity of the technology to detect radioactive surrogates such as Co, Ba, Sr, Cs, Ir and U on substrates of aluminum, clay, concrete and glass. It have been also demonstrated the capabilities of the technique for simultaneous and in situ analysis of explosive and radiological evidence in a post-detonation scenario

Real-time bioimpedance measurements of stem cellbased disease models-on-a-chip

In vitro disease models are powerful platforms for the development of drugs and novel therapies. Stem-cell based approaches have emerged as cutting-edge tools in disease modelling, allowing for deeper insights into previously unknown disease mechanisms. Hence the significant role of these disease-in-a-dish methods in therapeutics and translational medicine. Impedance sensing is a non-invasive, quantitative technique that can monitor changes in cellular behaviour and morphology in real-time. Bioimpedance measurements can be used to characterize and evaluate the establishment of a valid disease model, without the need for invasive end-point biochemical assays. In this work, two stem cell-based disease models-on-a-chip are proposed for acute liver failure (ALF) and age-related macular degeneration (AMD). The ALF disease model-on-a-chip integrates impedance sensing with the highly-differentiated HepaRG cell line to monitor in real-time quantitative and dynamic response to various hepatotoxins. Bioimpedance analysis and modelling has revealed an unknown mechanism of paracetamol hepatotoxicity; a temporal, dose-dependent disruption of tight junctions (TJs) and cell-substrate adhesion. This disruption has been validated using ultrastructural imaging and immunostaining of the TJ-associated protein ZO-1. Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world with a need for disease models for its currently incurable forms. Human induced pluripotent stem cells (hiPSCs) technology offers a novel approach for disease modelling, with the potential to impact translational retinal research and therapy. Recent developments enable the generation of Retinal Pigment Epithelial cells from patients (hiPSC-RPE), thus allowing for human retinal disease in vitro studies with great clinical and physiological relevance. In the current study, the development of a tissue-on- a-chip AMD disease model has been established using RPE generated from a patient with an inherited macular degeneration (case cell line) and from a healthy sibling (control cell line). A reproducible Electric Cell-substrate Impedance Sensing (ECIS) electrical wounding assay was conducted to mimic RPE damage in AMD. First, a robust and reproducible real-time quantitative monitoring over a 25-day period demonstrated the establishment and maturation of RPE layers on microelectrodes. A spatially-controlled RPE layer damage that mimicked cell loss in AMD was then initiated. Post recovery, significant differences in migration rates were found between case and control cell lines. Data analysis and modelling suggested this was due to the lower cell-substrate adhesion of the control cell line. These findings were confirmed using cell adhesion biochemical assays. Moreover, different-sized, individually-addressed square microelectrode arrays with high spatial resolution were designed and fabricated in-house. ECIS wounding assays were performed on these chips to study immortalized RPE migration. Migration rates comparable to those obtained with ECIS circular microelectrodes were determined. The two proposed disease-models-on-a-chip were then used to explore the therapeutic potential of the antioxidant N-Acetyl-Cysteine (NAC) on hiPSC-RPE and HepaRG cell recovery. Addition of 10 mM NAC at the end of a 24h paracetamol challenge caused a slight increase in the measured impedance, suggesting partial cell recovery. On the other hand, no effect on case hiPSC-RPE migration has been observed. More experiments are needed to examine the effect of different NAC concentrations and incubation periods. The therapeutic potential of electrical stimulation has also been explored. A preliminary study to evaluate the effect of electrical stimulation on RPE migration has been conducted. An externally applied direct current electric field (DC EF) of 300 mV/mm was found to direct the migration of the immortalized RPE cell line (hTERT-RPE1) perpendicular to the EF. The cells were also observed to elongate and to realign their long axes perpendicular to the applied EF. The proposed tissue-on-a-chip disease models are powerful platforms for translational studies. The potential of such platforms has been demonstrated through revealing unknown effects of acetaminophen on the liver as well as providing deeper insights into the underlying mechanisms of macular degeneration. Combining stem cell technology with impedance sensing provides a high throughput platform for studying patient-specific diseases and evaluating potential therapies

Stock structure of tropical tuna in the Indian Ocean: an otolith microchemistry approach

258 p.Entre las especies que desempeñan un papel importante en la economía azul, se encuentran las denominadas como túnidos tropicales; el listado, Katsuwonus pelamis, el rabil Thunnus albacares y el patudo Thunnus obesus. Estas especies son altamente migratorias y habitan las aguas tropicales y subtropicales de los tres océanos principales (Atlántico, Índico y Pacífico). Dentro de su área de distribución geográfica, el océano Índico es un caladero de vital importancia para las capturas de estas tres especies, sin embargo, es del que menos información se posee. Aunque en la actualidad cada una de las especies de túnidos tropicales se gestiona como un sólo stock en el Océano Índico, siguen existiendo dudas sobre la conectividad y dinámica espacial de las mismas. En este contexto, el objetivo principal de esta tesis es investigar la estructura de los stocks de túnidos tropicales en el Océano Índico, mediante el análisis microquímico de los otolitos (pares de piedras que se encuentran en el oído interno de los peces).AZT

Optimization of in vivo electroporation and comparison to microinjection as delivery methods for transgenesis in zebrafish (Danio rerio). Generation of a new neuronal zebrafish line

Transgenic zebrafish are important models for biomedical research. There are several technologies available for the generation of transgenics and for genome editing. However, methods for the delivery of exogenous components remain limited. In Zebrafish, the most used method is microinjection, which requires sophisticated technical skills and presents a low integration rate of large constructs. Alternatively, a few studies reported the use of electroporation as a delivery method for the generation of transgenic zebrafish; however, these protocols contain some limitations that reduce their widespread applicability. To overcome this, we based on the most recent published work reporting electroporation in zebrafish embryos, to implement optimizations in order to increase the number of embryos electroporated, the efficiency of plasmid DNA delivery and its integration in the germline. Electroporation rounds of 30 one-cell stage zebrafish embryos with 300 ng/uL of plasmid DNA in PBS using 35 V poring pulse and 5 V transfer pulse yielded the highest survival and efficiency. Compared to microinjection, the optimized electroporation protocol achieved similar fluorescence intensity and expression pattern, opening the way to becoming a practical and efficient alternative to microinjection. In parallel, a new calcium indicator pan-neuronal transgenic zebrafish line, elalv3:GCaMP6fEF05 was generated, through microinjection into one-cell stage zebrafish embryos, followed by 3 rounds of fish crosses, screens, selection and raising. The improvement of delivery methods, such as electroporation, will expand the generation of new zebrafish lines for the study of developmental and molecular biology that ultimately allows the exploration of new human therapeutic avenues.Os peixes-zebra transgénicos são modelos importantes para a pesquisa biomédica. Existem várias tecnologias disponíveis para a geração de transgénicos e edição do genoma. No entanto, os métodos para a entrega de componentes exógenos permanecem limitados. No peixe-zebra, o método mais utilizado é a microinjeção, que requer habilidades técnicas sofisticadas e apresenta taxa de integração de grandes construções reduzida. Alternativamente, alguns estudos relataram o uso de eletroporação como um método de entrega para a geração de peixes-zebra transgénicos; no entanto, esses protocolos contêm algumas limitações que reduzem sua aplicabilidade generalizada. Como tal, tendo por base um trabalho publicado recentemente relatando a eletroporação de embriões de peixe-zebra, implementaram-se otimizações a fim de aumentar o número de embriões eletroporados, a eficiência da entrega de DNA plasmídico e a sua integração na linha germinativa. Ciclos de eletroporação de 30 embriões de peixe-zebra no estado de uma célula com 300 ng / uL de DNA plasmídico em PBS usando um pulso de formação de poros de 35 V e pulso de transferência de 5 V obtiveram a maior taxa de sobrevivência e eficiência. Comparado à microinjeção, o protocolo de eletroporação otimizado alcançou uma intensidade de fluorescência e padrão de expressão semelhantes, abrindo caminho para se tornar uma alternativa prática e eficiente à microinjeção. Em paralelo, uma nova linha de peixe-zebra transgénica pan-neuronal, elalv3: GCaMP6fEF05 foi gerada, através da microinjeção em embriões no estado de uma célula, seguida por 3 rondas de cruzamentos de peixes, screens, seleção e criação. A otimização dos métodos de entrega, como a eletroporação, permite expandir a geração de novas linhas de peixe-zebra para o estudo da biologia molecular e do desenvolvimento que, em última análise, permite a exploração de novos caminhos terapêuticos para humanos