No description available.

No description available.

The application of ICP-MS to the fields of proteomics and genomics has arisen in part due to its ability to detect and quantify trace levels of S and P, which are major constituents in proteins and nucleic acids respectively. The development of collision/reaction cell technology and high resolution instruments has enabled these biologically important elements to be measured and quantified at the pg - ng ml-1 level. Despite these advances, the detection limits of P and S are still inferior compared to other elements. Oligonucleotides containing biotin functionality were labelled with Au nano-particles attached to a streptavidin protein to achieve site specific labelling, with 100% labelling efficiency. Each nano-particle contained ~86 Au atoms, resulting in an 882 fold signal enhancement for 24 base length oligonucleotides. However, this enhancement factor was only observed when one oligonucleotide bound to one nano-particle in a 1:1 ratio. Much lower Au labelling efficiencies and signal enhancements were observed when thiolated oligonucleotides were labelled with maleimide functionalised gold nano-particles. This was attributed to the extensive and difficult sample preparation steps that were required prior to labelling. The detection and quantification of adducts formed between DNA and the Pt anti-cancer drugs cisplatin and oxaliplatin were also investigated with ICP-MS. Acid digestion of the carbon based DNA matrix enabled Pt adducts to be quantified at low dose rates of 1 Pt atom per 1 500 000 nucleotides in ~12 μg DNA. Such sensitive mass spectrometric determinations could be employed in clinical tests to detect and quantify low level adducts formed in patients in-vivo. To complement ICP-MS analysis, electrospray ionisation linear ion trap mass spectrometry was employed to study the interaction of oxaliplatin with the four DNA nucleobases. Multiple stage mass spectrometry enabled detailed Pt-nucleobase adduct fragmentation pathways to be established. The method of DNA detection using P in conjunction with the collision cell, or cool plasma to form PO+ was also demonstrated and the limitations of the method, namely, polyatomic interferences and severe matrix effects were highlighted.

Mid-ocean ridge hydrothermal systems play an important role in the cycling of energy and mass between the solid earth and oceans. The on-axis low-temperature diffuse fluids (temperature lower than ~100 °C) carry ~90% of the on-axis heat fluxes, but diffuse fluids generation is poorly constrained. This study uses the abundance of the chalcophile elements, which form metal-sulphides in the rock record, to test models for diffuse fluids generation. These include mixing between seawater and high-temperature hydrothermal fluids and conductive cooling of high- temperature hydrothermal fluids. This thesis determined the concentrations of the elements of interest (As, Mo, Ag, Cd, Sn, and Tl) in geological reference materials using standard addition method in ICP-MS. These values were used to calibrate the analysis of samples from Pito Deep to trace the abundance of these elements within the upper oceanic crust. The results show that the Zn, Cu, As, Ag, Cd, Tl, and Pb are generally depleted in sheeted dikes and enriched in the lava unit and/or the transition zone, which is consistent with previous studies on fast-spreading EPR crust at Hole 504B, Hess Deep and Hole 1256D. The enrichment of these elements in the lava unit and/or the transition zone suggests that cooling high-temperature hydrothermal fluids to form diffuse fluids occurred in this iii iv area of the oceanic crust. Molybdenum and Sb are added into all units of the crust by recharging seawater. The concentrations of chalcophile elements in diffuse fluids were calculated by a mass balance. The results of this study favored a diffuse fluids generation model that involves mixing of seawater and high-temperature hydrothermal fluids. Results also show that the observed concentrations of Mo and Sb requires extra input source besides recharging seawater and oceanic crust, possibly particulates in seawater. / Graduate / juliatian2013@gmail.com

Une période intéressante de l'histoire précoce du système solaire est celle du disque, i.e. la période pendant laquelle se déroule la plupart des processus qui vont conduire du mélange de gaz et de poussières nébulaires à des grains et des planétésimaux, qui seront à un stade ultérieur le matériel de départ pour la formation des embryons planétaires et des planètes. Les témoins de cette époque sont les constituants des météorites primitives (chondrites), principalement les inclusions réfractaires (CAIs) et les chondres. Une des questions centrales dans la compréhension des processus à l'origine des CAIs et des chondres est celle du temps. Les travaux récents de Johan Villeneuve ont permis de démontrer que l'26Al et les isotopes du Mg étaient distribués dans le disque d'accrétion à un niveau d'homogénéité permettant d'utiliser le système 26Al-26Mg comme le chronomètre le plus précis qui soit des évènements qui se sont déroulés lors des 2 ou 3 premiers millions d'années du disque. Le but de cette thèse a été de reprendre toute l'étude de l'26Al avec des mesures de plus haute précision que les mesures existantes, en associant les mesures in-situ (sonde ionique) et en roche totale (HR-MC-ICPMS). Les développements analytiques mis en place pour mesurer les compositions isotopiques en Mg ont été appliqués à l'étude d'olivines réfractaires et de chondres de la météorite Allende, et d'olivines de la pallasite Eagle Station. L'ensemble des données a permis d'apporter des éléments de réponse sur les âges de formation des chondres et de leurs précurseurs, et sur l'origine des olivines réfractaires riches en Mg et la possibilité que celles-ci figurent parmi les précurseurs des chondres / The disk history is a very interesting period of the early Solar System history, i.e. the period during which occurred most of the processes leading from the mixing of nebular gas and dust to grains, and then planetesimals, which will then constitute the starting material for formation of planetary embryos and terrestrial planets. The witnesses of this period that we have in the laboratory are the chondrite constituents, mostly refractory inclusions (CAIs) and chondrules. One of the central questions regarding the processes leading to the formation of CAIs and chondrules is the timing. Villeneuve et al. (2009, 2011) have shown that 26Al and Mg isotopes were homogeneously distributed in the accretion disk, at a level allowing the use of the 26Al-26Mg system as the most precise short-lived chronometer to constrain the 2 or 3 first million years of the disk history. My PhD project aimed at reconsidering the 26Al study with more precise measurements, and by combining in-situ (by MC-SIMS) and bulk (by HR-MC-ICPMS) analyses. The analytical developments we set for Mg-isotope measurements (because of the high precision needed) were then applied to a set of extraterrestrial materials, including Mg-rich isolated olivines and Mg-rich olivines in porphyritic type I chondrules from the Allende CV3 meteorite, as well as chondrules from the same meteorite, and olivines from the Eagle Station pallasite. The whole data set allowed to answer questions such as (i) the origin of chondrule precursor materials and the time of chondrule formation, as well as (ii) the origin of Mg-rich refractory olivines, and the possibility that the latters were part of chondrule precursors

A represa Billings é o maior reservatório de água que abastece o estado de São Paulo. Está localizada na bacia do Alto Tietê na região metropolitana de São Paulo, em uma área de proteção ambiental. Contudo, desde o início da sua inundação, vem sofrendo sérias agressões ambientais. Entre elas, o fluxo de entrada de água do rio Pinheiros, usado para controle de enchentes na região metropolitana de São Paulo. A constante entrada de contaminantes na represa se torna preocupante, considerando que, no seu entorno, há diferentes tipos de assentamentos, entre os quais de famílias de pescadores, que usam estas águas sem tratamentos convencionais para consumo doméstico e pesca artesanal para subsistência. Portanto, este estudo teve como objetivo realizar uma avaliação temporal dos níveis de metais presentes na água e em tecidos dos peixes da represa, correlacionando estes valores com o fluxo de entrada de água do rio Pinheiros e do índice pluviométrico na região. Durante o período de um ano, cerca de 800 indivíduos, dentre as principais espécies de peixes consumidas na região Geophagus brasiliensis (acará), Hoplias malabaricus (traíra), Tilapia rendalli (tilápia) e Astyanax ssp (lambari), de sete pontos de pesca, foram coletadas e analisados. Amostras de águas foram coletadas em 13 pontos sugeridos pelos pescadores locais. Considerando cada espécie de peixe analisada, os níveis de metais estão na mesma ordem de magnitude, independentemente da região de captura. Os níveis de Cr, em cerca de 60% dos acarás, 98% dos lambaris, 67% dos traíras e 100% de tilápia não atenderam ao limite estabelecido pela ANVISA. Cu e Hg, em todas as amostras atenderam aos limites estabelecidos pela legislação nacional. A inserção das águas do rio Pinheiros claramente afeta a qualidade da água da represa. As regiões mais contaminadas são: Pedreira, Margem do Bororé, Alvarenga, Barragem Taquacetuba, Casa Caída e Ilha do Biguá. Observou-se também que 100% de amostras não atendem ao limite estabelecido pelo CONAMA; para Cu, Mn, Ni, cerca de 50% não cumprem o limite estipulado para Cd e 20% para Zn. Em linhas gerais, observou-se que esta inserção altera todo o regime natural da represa, mas que ainda assim é possível absorver a contaminação recebida. / The Billings Dam is the largest reservoir of water that supplies in the state of São Paulo. It is part of the Alto Tiete basin, which is located in the metropolitan region of São Paulo in an environmentally protected area. In spite of that, since the beginning of its flooding, several environmental aggressions were observed. Among them the inflow of water from Pinheiros river, used to control floods in the metropolitan region of Sao Paulo .The constant input of contaminants in the dam becomes worrisome, considering that, in its surroundings, there are different kinds of settlements, among them families of fishermen, who use these waters without conventional treatments for domestic consumption and artisanal fishing for livelihood. Therefore, this study aimed to carry out a temporal evaluation of metal levels present in dam\'s water and fish tissue, correlating these values with the water input flow of Pinheiros River and pluviometric index in the region. During a period of one year, circa of 800 individuals among the main consumed fish species in the region Geophagus brasiliensis (acará), Hoplias malabaricus (traíra), Tilapia rendalli (tilápia) e Astyanax ssp (lambari), from seven fishing places were collected and analysed. It was also collected water from thirteen places chosen by local fishermen. Considering each fish specimen analyzed, the levels of metals are in the same order of magnitude regardless of the region of capture. The levels of Cr in circa of 62% of acarás, 98% of lambaris, 67% of traíras and 100% of tilapia do not meet the limit stipulated by ANVISA. Cu and Hg, in all samples meet the limits set by national legislation. The Pinheiros river water clearly affects the quality of dam\'s water. The most contaminated regions were: Pedreira, Margem do Bororé, Alvarenga, Barragem Taquacetuba, Casa Caída and Ilha do Biguá. It was observed that 100% of samples do not meet the limits established for water quality by CONAMA for Cu, Mn and Ni, 50% do not meet the limit for Cd and 20% for Zn . In general, we can observe the entry of to the waters of Pinheiros River during operation of the flotation system and even during the flood control changes the whole natural scheme of the dam, although the dam still manages to absorb the contamination that is received.

A represa Billings é o maior reservatório de água que abastece o estado de São Paulo. Está localizada na bacia do Alto Tietê na região metropolitana de São Paulo, em uma área de proteção ambiental. Contudo, desde o início da sua inundação, vem sofrendo sérias agressões ambientais. Entre elas, o fluxo de entrada de água do rio Pinheiros, usado para controle de enchentes na região metropolitana de São Paulo. A constante entrada de contaminantes na represa se torna preocupante, considerando que, no seu entorno, há diferentes tipos de assentamentos, entre os quais de famílias de pescadores, que usam estas águas sem tratamentos convencionais para consumo doméstico e pesca artesanal para subsistência. Portanto, este estudo teve como objetivo realizar uma avaliação temporal dos níveis de metais presentes na água e em tecidos dos peixes da represa, correlacionando estes valores com o fluxo de entrada de água do rio Pinheiros e do índice pluviométrico na região. Durante o período de um ano, cerca de 800 indivíduos, dentre as principais espécies de peixes consumidas na região Geophagus brasiliensis (acará), Hoplias malabaricus (traíra), Tilapia rendalli (tilápia) e Astyanax ssp (lambari), de sete pontos de pesca, foram coletadas e analisados. Amostras de águas foram coletadas em 13 pontos sugeridos pelos pescadores locais. Considerando cada espécie de peixe analisada, os níveis de metais estão na mesma ordem de magnitude, independentemente da região de captura. Os níveis de Cr, em cerca de 60% dos acarás, 98% dos lambaris, 67% dos traíras e 100% de tilápia não atenderam ao limite estabelecido pela ANVISA. Cu e Hg, em todas as amostras atenderam aos limites estabelecidos pela legislação nacional. A inserção das águas do rio Pinheiros claramente afeta a qualidade da água da represa. As regiões mais contaminadas são: Pedreira, Margem do Bororé, Alvarenga, Barragem Taquacetuba, Casa Caída e Ilha do Biguá. Observou-se também que 100% de amostras não atendem ao limite estabelecido pelo CONAMA; para Cu, Mn, Ni, cerca de 50% não cumprem o limite estipulado para Cd e 20% para Zn. Em linhas gerais, observou-se que esta inserção altera todo o regime natural da represa, mas que ainda assim é possível absorver a contaminação recebida. / The Billings Dam is the largest reservoir of water that supplies in the state of São Paulo. It is part of the Alto Tiete basin, which is located in the metropolitan region of São Paulo in an environmentally protected area. In spite of that, since the beginning of its flooding, several environmental aggressions were observed. Among them the inflow of water from Pinheiros river, used to control floods in the metropolitan region of Sao Paulo .The constant input of contaminants in the dam becomes worrisome, considering that, in its surroundings, there are different kinds of settlements, among them families of fishermen, who use these waters without conventional treatments for domestic consumption and artisanal fishing for livelihood. Therefore, this study aimed to carry out a temporal evaluation of metal levels present in dam\'s water and fish tissue, correlating these values with the water input flow of Pinheiros River and pluviometric index in the region. During a period of one year, circa of 800 individuals among the main consumed fish species in the region Geophagus brasiliensis (acará), Hoplias malabaricus (traíra), Tilapia rendalli (tilápia) e Astyanax ssp (lambari), from seven fishing places were collected and analysed. It was also collected water from thirteen places chosen by local fishermen. Considering each fish specimen analyzed, the levels of metals are in the same order of magnitude regardless of the region of capture. The levels of Cr in circa of 62% of acarás, 98% of lambaris, 67% of traíras and 100% of tilapia do not meet the limit stipulated by ANVISA. Cu and Hg, in all samples meet the limits set by national legislation. The Pinheiros river water clearly affects the quality of dam\'s water. The most contaminated regions were: Pedreira, Margem do Bororé, Alvarenga, Barragem Taquacetuba, Casa Caída and Ilha do Biguá. It was observed that 100% of samples do not meet the limits established for water quality by CONAMA for Cu, Mn and Ni, 50% do not meet the limit for Cd and 20% for Zn . In general, we can observe the entry of to the waters of Pinheiros River during operation of the flotation system and even during the flood control changes the whole natural scheme of the dam, although the dam still manages to absorb the contamination that is received.

Une technique d'ablation laser dite en champ proche a été développée pour l'analyse chimique d'échantillons solides à l'échelle sub-micrométrique. Cette technique combine un laser Nd:YAG nanoseconde, un microscope à force atomique AFM et un spectromètre de masse à plasma à couplage inductif (ICPMS). Afin d'améliorer la résolution spatiale de la technique d'ablation laser classique, l'effet de champ proche, consistant à amplifier l'énergie du laser très localement a été mis à profit. Cet effet est obtenu par illumination, par un faisceau laser, de la pointe conductrice de l'AFM placée à quelques nanomètres (5-30 nm) de la surface d'un échantillon. En appliquant cette technique d'ablation sur des échantillons conducteurs, l'or et le tantale, et un échantillon semi-conducteur, le silicium, une résolution latérale de 100 nm et des profondeurs de quelques nanomètres ont été obtenues. Deux codes numériques développés au laboratoire ont permis l'étude de deux phénomènes intervenant aux alentours de la pointe : l'amplification du champ électrique du laser par effet de pointe, et le chauffage induit par le laser à la surface de l'échantillon. L'influence des principaux paramètres opératoires sur ces deux phénomènes d'amplification et de chauffage a été étudiée. Une étude expérimentale multiparamétrique a été réalisée afin d'étudier l'influence des différents paramètres (fluence du laser, longueur d'onde du laser, nombre de tirs laser, distance pointe-échantillon, nature et dimensions de la pointe, nature de l'échantillon) sur l'efficacité d'ablation, sur les dimensions des cratères et sur la quantité de matière ablatée. / A near field laser ablation method was developed for chemical analysis of solid samples at sub-micrometric scale. This analytical technique combines a nanosecond laser Nd:YAG, an Atomic Force Microscope (AFM), and an inductively coupled plasma mass spectrometer (ICPMS). In order to improve the spatial resolution of the laser ablation process, the near-field enhancement effect was applied by illuminating, by the laser beam, the apex of the AFM conductive sharp tip maintained at a few nanometers (5 to 30 nm) above the sample surface. The interaction between the illuminated tip and the sample surface enhances locally the incident laser energy and leads to the ablation process. By applying this technique to conducting gold and tantalum samples, and semiconducting silicon sample, a lateral resolution of 100 nm and depths of a few nanometers were demonstrated. Two home-made numerical codes have enabled the study of two phenomena occurring around the tip: the enhancement of the laser electrical field by tip effect, and the induced laser heating at the sample surface. The influence of the main operating parameters on these two phenomena, amplification and heating, was studied. An experimental multi-parametric study was carried out in order to understand the effect of different experimental parameters (laser fluence, laser wavelength, number of laser pulses, tip-to-sample distance, sample and tip nature) on the near-field laser ablation efficiency, crater dimensions and amount of ablated material.

No description available.

La nanoscience est basée sur les changements de propriétés des particules lorsque leur diamètre est inférieur à 100 nm (i.e. nanoparticules, NPs). Devant l’utilisation croissante de tels NPs, et leur déversement probable dans l’environnement, l’évaluation de leurs risques sur la santé humaine et l’environnement est un enjeu majeur. Dans le cadre de la protection des eaux et des sols, l’évaluation de la qualité des eaux de surface est particulièrement importante, notamment dans les zones humides (ZHs), où la dynamique des métaux toxique (i.e. As, Pb, Ni, Cr, Hg) est complexe et dépend des conditions redox du milieu. Comme les NPs de magnétite (nano-Fe3O4), naturelles ou manufacturées, sont reconnues pour leur capacité d’adsorption importante face aux métaux lourds, leurs interactions dans les ZHs ripariennes (ZHRs) avec les ETMs restent critiques quant à leurs impacts directs ou indirects. Ainsi, l’objectif de cette thèse était d’étudier le rôle des nano-Fe3O4 manufacturées (~10nm) et des oxydes de fer naturels sur la dynamique des ETMs dans les eaux de surfaces et les sols de ZHRs. Ainsi, dans un premier volet portant sur des précipités colloïdaux naturels provenant de produits de reoxydation en milieu riparian (soumis à des oscillations redox), la distribution spatiale des éléments a été effectuée par cartographie isotopique nanoSIMS (i.e. 75As-, 56Fe16O-, le soufre (32S-) et la matière organique (12C14N-), alors que la spéciation du soufre a été évaluée par adsorption des rayons X au seuil K du soufre (S) (XANES). Ces analyses ont permis de mettre en évidences les interactions entre les oxydes de fer naturels, la matière organique naturelle (MON) et un métalloïde toxique, l’arsenic. Nos résultats suggèrent, par colocalisation statistique des images nanoSIMS, l’existence de deux types d’interaction : (1) 12C14N-, 32S-, 56Fe16O- et 75As-, et (2) 12C14N-, 32S- et 75As-. La coexistence des formes de S oxydées et réduites, confirmées par les analyses XANES, pourrait être attribuée à la lente cinétique d’oxydation de la MON. Ainsi, ce premier volet montre qu’en plus des interactions MON, oxydes de fer et As, de possibles interactions directes entre As et NOM à travers des groupements fonctionnels soufrés (e.g. thiols) sont aussi possibles en milieu oxydé. Dans un second volet, l’effet des nano-Fe3O4 (~ 10 nm) sur la mobilité des éléments traces (ETs) et des colloïdes, dans l'horizon organominéral d’un sol naturel de ZHR, a été évaluée à l’aide de colonnes de sol. Nos résultats montrent que l’enrobage des nanoparticules semble influencer la mobilité de la MON et des ETs du sol. En effet, la mobilité des ETs semble augmenter en présence de nano-Fe3O4 nus, suggérant des associations où la MON stabiliserait les nanoparticules et augmenterait leur mobilité ainsi que celle des ETs associés. / Nanoscience is based on changes in particle properties when their diameter is below 100 nm (ie nanoparticles, NPs). Considering the increasing use of such NPs and their discharge into the environment, the assessment of their risks to human health and the environment is a major issue. Underneath the protection of waters and soils, the surface water assessment quality is particularly important, especially in wetlands, where the toxic metals dynamic (e.g. As, Pb, Ni, Cr , Hg) is complex and depends on the redox conditions of the environment. As magnetite (nano-Fe3O4), a natural or manufactured NP, is known for its significant adsorption capacity with heavy metals, their interactions in riparian wetlands with trace metals (TMs) remain critical concerning their direct of indirect impact on trace metals (TMs) mobility. The objective of this thesis was to study the role of manufactured nano-Fe3O4 (~ 10nm) and natural iron oxides on the TMs dynamics in wetland surface waters and soils. Therefore, in a first part considering natural colloidal precipitates from reoxidation products from riparian areas (subject to redox oscillations), a spatial distribution of elements was performed using nanoSIMS isotope mapping (i.e. 75As-, 56Fe16O-, sulfur (32S-) and organic matter (12C14N-), while the sulfur speciation was evaluated X-ray adsorption at K edge of the sulfur (S) (XANES). These analyzes allowed to highlight the interactions between natural iron oxides, natural organic matter (NOM) and a toxic metalloid, As. Our results suggest, with a statistical colocalization of nanoSIMS images, the existence of two interaction types: (1) 12C14N-, 32S-, 56Fe16O- and 75As-, and (2) 12C14N-, 32S- and 75As-. The coexistence of the oxidized and reduced forms of S, confirmed by the XANES analyses might be attributed to the slow oxidation kinetic of MON. Thus, this first part shows that in addition to the known interactions between MON, iron oxides and As, a possible direct interaction between As and NOM through sulfur functional groups (e.g. thiols) are also possible in oxidized environment. In a second part, the effect of nano-Fe3O4 (~ 10 nm) on trace elements (TEs) and colloids mobility in the organomineral horizon of a natural wetland soil was assessed using soil columns. Our results show that the nanoparticles coating influences the mobility of NOM and TMs. Indeed, the TMs mobility increases in presence of naked nano-Fe3O4, suggesting associations where NOM stabilizes the nanoparticles and increase the nanoparticles and associated TMs mobility. This mechanism seems less possible with coated nano-Fe3O4 where MON blocks the coating adsorption sites and therefore the adsorption of metals.