There is a large body of clinical and experimental evidence linking heart disease with impairment of myocardial energetics, particularly the creatine kinase (CK) system. The goal of the experiments described in this thesis was to develop and study models of increased CK phosphotransfer, by overexpressing the CK isoenzymes and/or augmenting intracellular creatine stores. Pilot experiments were performed in cultured cells, which were used to (a) study the effects of CK overexpression in vitro, and (b) validate constructs prior to generation of transgenic mice. Expression was verified at the protein level for all constructs in HL-1 and HEK293 cells, and enzymatic activity was confirmed. Mitochondrial CK (CKmt) was expressed in the mitochondria, as expected, and CKmt overexpression was associated with a significant reduction in cell death in a model of ischemia/reperfusion injury (68.1 ± 7.1% of control, p≤0.05). Transgenic mice overexpressing CKmt in the heart were generated by a targeted approach, using PhiC31 integration at the ROSA26 locus. Transgene expression was confirmed in vitro in embryonic stem cells, and in vivo at the mRNA and protein levels. There was only a modest increase in CKmt activity; therefore, homozygous transgenic mice were generated to increase expression levels, and had 27% higher CKmt activity than wild-types (p≤0.01). Mitochondrial localization of CKmt was confirmed by electron microscopy. Citrate synthase activity, a marker of mitochondrial volume, was ~10% lower in transgenic mice (p≤0.05). Baseline phenotyping studies found that CKmt-overexpressing mice have normal cardiac structure and function. These mice are currently being backcrossed onto a pure C57BL/6 background for further studies in models of heart disease. In addition to CKmt, transgenic mice overexpressing the cytosolic CK isoenzymes, CK-M and CK-B, were generated. Due to the modest level of expression observed at ROSA26, random-integration transgenesis was used, and multiple lines were generated for each construct (carrying 2 or 6 transgene copies in the CK-M line; 2, 3, or ~30 in CK-B). Transgene expression was validated at the mRNA, protein, and activity levels. These lines are currently being expanded for further validation and phenotyping studies. Previous experiments in our group have demonstrated that increasing intracellular creatine (Cr) reduces ischemia/reperfusion injury, and a series of in vitro experiments was performed to determine whether this effect may be mediated by inhibition of the mitochondrial permeability transition pore (mPTP). The mPTP plays a significant role in ischemia/reperfusion, and there is evidence linking the CK system to regulation of the mPTP. Therefore, a model was developed to test whether Cr affects mPTP opening in cardiac-derived HL-1 cells, as this mechanism may contribute to the protective effect observed in vivo. Cr incubation conditions were determined empirically, and 24-hour incubation with 5mM or 10mM Cr was found to significantly delay mPTP opening, to a similar degree to the established mPTP inhibitor, cyclosporin A. This provides evidence that Cr may exert protective effects in the heart by a variety of mechanisms, in addition to its traditional role in energy metabolism. In summary, the experiments conducted in this thesis have produced a range of tools for studying augmentation of the creatine kinase system as a therapeutic target in heart disease. The results of in vitro assays indicate that mitochondrial CK may be a particularly promising target, and that inhibition of the mitochondrial permeability transition pore may contribute to the cardioprotective effect of creatine. Finally, the transgenic models generated and validated over the course of this project will allow for a wide range of future studies into the potential benefits of CK overexpression in the mammalian heart.

No presente trabalho analisa-se o comportamento do aço de reforço ante à corrosão, com o uso dos inibidores: nitrito de sódio, fosfato de sódio e etalonamina, na água de poros contaminada com cloreto, e no concreto com a finalidade de analisar seus resultados e seus mecanismos diferenciados. Para cumprir este objetivo o presente trabalho divide-se em duas etapas: uma primeira etapa baseada em simular sinteticamente a água de poro de um concreto, cuja solução é KOH 28g/l+NaOH 4g/l. Essa água de poro é simulada em ambiente marinho, cuja solução é KOH 28g/l + NaOH 4g/l+NaCl 35g/l, e a esta solução referência incorporamse os inibidores (20g/l da cada um). Realizaram-se ensaios de espectroscopia de impedância eletroquímica (EIE) (após 3 e 72 horas de imersão) e curvas de polarização (após 72 horas de imersão) com vistas a obter respostas da cinética da corrosão ante a cada solução. Obteve-se o melhor comportamento para a água de poros. No caso da água de poro contaminada por cloretos, o melhor comportamento se obteve para o inibidor nitrito de sódio. Na segunda etapa adotou-se apenas o inibidor nitrito de sódio, pois estatisticamente as eficiências dos três inibidores foram muito similares. Analisou-se o nitrito de sódio em amostras reais de concreto armado contaminado com cloreto de sódio. Para isso se elegeram dois tipos de cimentos (CP IV e CP V) e três relações água-cimento (a/c-0.4, a/c-0.5, a/c- 0.65). Para simular o ambiente marinho, realizaram-se ensaios acelerados de cloretos. Comparam-se métodos de análises simuladas sinteticamente e reais, concluindo-se em ambos meios, embora fossem um solido e outro líquido o inibidor Nitrito de Sódio aumento a sua eficiência com os ciclos de exposição. / In this paper it is analyzed the behavior of reinforcing steel against corrosion using inhibitors: sodium nitrate, sodium phosphate and ethanolamine in water contaminated with chlorides pore and concrete, in order to analyzing the results and different mechanisms. To meet the objective of this work, it was divided into two stages, a first stage based on synthetically simulate the pore water of a concrete, through the following solution KOH 28g/l+NaOH 4g/l, this same solution simulated pore water to a marine environment it would be KOH 28g/l + NaOH 4g/l+NaCl 35g/l, it is then incorporated into both reference solutions inhibitors in a proportion, (20g/l de cada um). Assays were performed electrochemical impedance spectroscopy (EIE) (last 3 hours and 72 hours of immersion) and polarization curves (last 72 hours of immersion) in order to obtain responses corrosion kinetics in each solution. the best performance was obtained in the pore water. In the case of water contaminated with chlorides pore, the best performance was obtained in the presence of sodium nitrite inhibitor. In the second step was performed only with the inhibitor sodium nitrate, as statistically efficiencies of the three inhibitors were similar. Sodium nitrate was analyzed in real samples of reinforced concrete contaminated with chlorides of sodium. So they were chosen two types of cement CP- IV and CP-V, cement water three relationships 0.4, a/c-0.5, a/c- 0.65. In this case to simulate the marine environment, accelerated tests were performed chloride. They were compared the methods of analysis, simulated synthetically and simulated in real concrete.

The difficulty of assessing risk of sediment-associated contaminant mixtures to benthic ecosystems is often attributed to understanding the bioavailable fraction of each contaminant. These issues have led to the development of the toxicity identification evaluation (TIE). Past pore water TIE testing on Illinois River sediments has indicated that ammonia was the primary contaminant. The current study, however, suggests that ammonia is no longer the primary contaminant of concern, but rather non-polar organics, including polycyclic aromatic hydrocarbons, are the primary cause for toxicity in the Illinois River Complex (IRC). Summer of 2007 testing showed that six out of the seven sites that proceeded to Phase I testing exhibited a significant increase in survival with the addition of the non-polar organic amendment powdered coconut charcoal (PCC), while zeolite (ammonia amendment) and Resin Tech SIR 300 (cationic metals amendment) did not significantly increase survival suggesting that non-polar organics are the source of toxicity. In addition, Phase II testing suggested that concentrations of PAHs were high enough to cause the observed toxicity, which confirmed the results of Phase I testing. Additional seasonal-based sampling (i.e., fall, winter, spring, and summer 2008) supported the summer findings, with little variation between toxicity and concentrations, with 46% of the sites being improved with the addition of PCC in Phase I testing. The results of Phase I and Phase II contradicted past pore water TIE studies as non-polar organics were suggested as the source of toxicity rather than ammonia. Thus, both pore water and whole sediment TIE methodologies were used on two selected sites. The results of this study suggested that discordance between the past pore water TIEs and the current whole sediment TIE were attributed to the methodologies and on a lesser note the test organisms used. The present study provides data that could be used in combination with previous work to more accurately characterize the sources and spatial trends of toxicity in Illinois River sediments for future risk assessment and mitigation. Furthermore, the present study showed that while TIE methodologies are a valuable tool in assessing risk associated with contaminants in aquatic system, further research in understanding the role that each TIE method may serve in risk assessment is also important.

abstract: This study presents the results of one of the first attempts to characterize the pore water pressure response of soils subjected to traffic loading under saturated and unsaturated conditions. It is widely known that pore water pressure develops within the soil pores as a response to external stimulus. Also, it has been recognized that the development of pores water pressure contributes to the degradation of the resilient modulus of unbound materials. In the last decades several efforts have been directed to model the effect of air and water pore pressures upon resilient modulus. However, none of them consider dynamic variations in pressures but rather are based on equilibrium values corresponding to initial conditions. The measurement of this response is challenging especially in soils under unsaturated conditions. Models are needed not only to overcome testing limitations but also to understand the dynamic behavior of internal pore pressures that under critical conditions may even lead to failure. A testing program was conducted to characterize the pore water pressure response of a low plasticity fine clayey sand subjected to dynamic loading. The bulk stress, initial matric suction and dwelling time parameters were controlled and their effects were analyzed. The results were used to attempt models capable of predicting the accumulated excess pore pressure at any given time during the traffic loading and unloading phases. Important findings regarding the influence of the controlled variables challenge common beliefs. The accumulated excess pore water pressure was found to be higher for unsaturated soil specimens than for saturated soil specimens. The maximum pore water pressure always increased when the high bulk stress level was applied. Higher dwelling time was found to decelerate the accumulation of pore water pressure. In addition, it was found that the higher the dwelling time, the lower the maximum pore water pressure. It was concluded that upon further research, the proposed models may become a powerful tool not only to overcome testing limitations but also to enhance current design practices and to prevent soil failure due to excessive development of pore water pressure. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2011

This thesis presents an investigation of reactive transport of species in porous media, with the aim to understand better and predict the fate of radionuclide in engineered and natural barriers of future deep geological disposal facilities for nuclear waste. The work involves developments of several pore-scale models for simulating reactive transport by coupling convective, adsorptive and diffusive processes. Pore network models (PNM) are amongst the appealing approaches that provide a suitable description for dealing with mutable pore space structures. Such models have been used to describe conservative as well as reactive transport in saturated and unsaturated porous media. In the present thesis, pore network models based on a regular tessellation of truncated octahedral cells are proposed and developed to simulate mass transport in porous media with incomplete pore space information due to limitation of existing characterisation techniques. Bentonite and Opalinus Clay are selected to illustrate the methodology. The micro- and meso-structure of these clays and their effects on the transport behaviour are investigated. The research shows that the clays are anisotropic and heterogeneous with fast diffusion parallel to the bedding plane and slow diffusion perpendicular to the bedding plane. In addition, different types of species have different accessible porosity and macroscopic diffusion coefficients. The anisotropy and heterogeneity of clays are achieved by different length scales and percentage of pores in different directions in the pore network models. The transport behaviour of various species, including sorption and anion exclusion, is simulated and analyzed. The effect of sorption is simulated via changing the pore radii by a coarse grained mathematical formula or by a formula directly in each pore. The results are in good agreement with experimentally measured macroscopic (bulk) diffusivities for the materials studied, including anisotropic diffusion coefficients. This lends strong support to the physical realism of the proposed models. The developed methodology can be used for any micro and meso-porous material with known distribution of pore sizes. It can be extended to other pore space changing mechanisms, in addition to sorption, to derive mechanism-based evolution laws for the transport parameters of porous media.

No presente trabalho analisa-se o comportamento do aço de reforço ante à corrosão, com o uso dos inibidores: nitrito de sódio, fosfato de sódio e etalonamina, na água de poros contaminada com cloreto, e no concreto com a finalidade de analisar seus resultados e seus mecanismos diferenciados. Para cumprir este objetivo o presente trabalho divide-se em duas etapas: uma primeira etapa baseada em simular sinteticamente a água de poro de um concreto, cuja solução é KOH 28g/l+NaOH 4g/l. Essa água de poro é simulada em ambiente marinho, cuja solução é KOH 28g/l + NaOH 4g/l+NaCl 35g/l, e a esta solução referência incorporamse os inibidores (20g/l da cada um). Realizaram-se ensaios de espectroscopia de impedância eletroquímica (EIE) (após 3 e 72 horas de imersão) e curvas de polarização (após 72 horas de imersão) com vistas a obter respostas da cinética da corrosão ante a cada solução. Obteve-se o melhor comportamento para a água de poros. No caso da água de poro contaminada por cloretos, o melhor comportamento se obteve para o inibidor nitrito de sódio. Na segunda etapa adotou-se apenas o inibidor nitrito de sódio, pois estatisticamente as eficiências dos três inibidores foram muito similares. Analisou-se o nitrito de sódio em amostras reais de concreto armado contaminado com cloreto de sódio. Para isso se elegeram dois tipos de cimentos (CP IV e CP V) e três relações água-cimento (a/c-0.4, a/c-0.5, a/c- 0.65). Para simular o ambiente marinho, realizaram-se ensaios acelerados de cloretos. Comparam-se métodos de análises simuladas sinteticamente e reais, concluindo-se em ambos meios, embora fossem um solido e outro líquido o inibidor Nitrito de Sódio aumento a sua eficiência com os ciclos de exposição. / In this paper it is analyzed the behavior of reinforcing steel against corrosion using inhibitors: sodium nitrate, sodium phosphate and ethanolamine in water contaminated with chlorides pore and concrete, in order to analyzing the results and different mechanisms. To meet the objective of this work, it was divided into two stages, a first stage based on synthetically simulate the pore water of a concrete, through the following solution KOH 28g/l+NaOH 4g/l, this same solution simulated pore water to a marine environment it would be KOH 28g/l + NaOH 4g/l+NaCl 35g/l, it is then incorporated into both reference solutions inhibitors in a proportion, (20g/l de cada um). Assays were performed electrochemical impedance spectroscopy (EIE) (last 3 hours and 72 hours of immersion) and polarization curves (last 72 hours of immersion) in order to obtain responses corrosion kinetics in each solution. the best performance was obtained in the pore water. In the case of water contaminated with chlorides pore, the best performance was obtained in the presence of sodium nitrite inhibitor. In the second step was performed only with the inhibitor sodium nitrate, as statistically efficiencies of the three inhibitors were similar. Sodium nitrate was analyzed in real samples of reinforced concrete contaminated with chlorides of sodium. So they were chosen two types of cement CP- IV and CP-V, cement water three relationships 0.4, a/c-0.5, a/c- 0.65. In this case to simulate the marine environment, accelerated tests were performed chloride. They were compared the methods of analysis, simulated synthetically and simulated in real concrete.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work we present a computational study of the electroporation process of lipid membranes in the presence of water. First, we developed an investigation of the formation of pores through simulations based on classical molecular dynamics using NAMD code. Subsequently we developed ab initio study using density functional theory, as implemented in the SIESTA code. This analysis showed the formation of pores within the lipid bilayer 1ns after the application of external electric field, 300 K. We found that set temperatures above 300 K may reduce the simulation time. We also observed a rearrangement of water molecules of a Okuno Tanioka cone due to the action of the electric field. Interestingly, this induced an increase of the number of hydrogen bonds, which was not observed using apolar molecules such as chloroform. After, we performed the analysis of structural and electronic properties of the structures of phospholipids,which were extracted from the molecular dynamics calculations. It is noteworthy that the action of the electric field changed the energy gap of both the structures of isolated phospholipid as for the lipid bilayer configuration. Through maps of electrostatic potential, we showed that the electric field leads to a polarization of phospholipid, which induced a torque in the electric dipole moments of the water molecule. The rotation of the electric dipole moments gave rise to stress in the lipid bilayer, which by itself was not enough to break it. In summary, the presence of water was critical since under the action of an electric field the molecules rearranged to form a cone. This fact, associated with the weakening of the lipid membrane due the stress from the realignment electric dipole, was the responsible for the poration process. / Neste trabalho, apresentamos um estudo computacional do processo de eletroporação de membranas lipídicas na presença de água. Na primeira etapa, realizamos a dinâmica da formação de poros através de simulações baseadas na dinâmica molecular clássica, utilizando o código NAMD. Posteriormente, desenvolvemos um estudo ab initio, empregando a teoria do funcional da densidade, conforme implementada no programa SIESTA. Os resultados da primeira análise mostraram a formação de poros no interior da bicamada após 1ns de aplicação de um campo elétrico externo, a uma temperatura de 300 K. Também verificamos que, para temperaturas acima de 300 K, esse tempo se reduz. Observamos um rearranjo das moléculas de água na forma de um cone de Okuno Tanioka devido à ação do campo elétrico. Isso ocasiona um aumento no número de ligações de hidrogênio das mesmas, o que não foi observado com o uso de moléculas apolares como o clorofórmio. Na segunda etapa, realizamos a análise das propriedades eletrônicas e estruturais, utilizando as estruturas dos fosfolipídios provindas dos cálculos de dinâmica molecular. Mostramos que a ação do campo elétrico modifica o gap de energia tanto da estrutura do fosfolipídio isolado quanto para a configuração de bicamada lipídica. Através dos mapas do potencial eletrostático, mostramos que a ação do campo elétrico leva a uma polarização do fosfolipídio ocasionando um torque no momentos de dipolo elétrico da molécula. A rotação dos momentos de dipolo elétrico causa um estresse na bicamada, que por si só não é capaz de rompe-la. Dessa forma, a presença da água é fundamental, pois diante a ação do campo elétrico as moléculas se reordenam arranjando-se de maneira a formar um cone. Este fato, associado ao enfraquecimento da membrana lipídica, devido ao estresse causado pelo realinhamento nos momentos de dipolo elétrico, são a origem do processo de poração.

Submitted by JOÃO PAULO PICOLINI null (jpp1795@gmail.com) on 2017-05-31T17:09:26Z No. of bitstreams: 1 João Paulo Picolini - dissertação.pdf: 17065279 bytes, checksum: f43bb6d003d8f416c59e61ce87a2f7e7 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-31T18:50:57Z (GMT) No. of bitstreams: 1 picolini_jp_me_rcla.pdf: 17065279 bytes, checksum: f43bb6d003d8f416c59e61ce87a2f7e7 (MD5) / Made available in DSpace on 2017-05-31T18:50:57Z (GMT). No. of bitstreams: 1 picolini_jp_me_rcla.pdf: 17065279 bytes, checksum: f43bb6d003d8f416c59e61ce87a2f7e7 (MD5) Previous issue date: 2017-04-10 / Foram estudadas as pressões de poros em poços localizados numa área central da Bacia de Santos, onde ocorrem Zonas de Pressão de Poros Anormal (ZPA), intervalos estratigráficos caracterizados por pressões de poros anormalmente elevadas (sobrepressão). Atenção especial foi dedicada à Sequência Deposicional K90, Santoniano ao Campaniano, constituída pelas formações Juréia e Itajaí-Açu, por sua vez composta por pelitos do Folhelho-Selo e arenitos do Reservatório Principal (Membro Ilha-Bela). A área de estudos possui cerca de 1900 km2 e localiza-se a cerca de 120km do litoral do Estado de São Paulo, apresentando acumulações de gás no Reservatório Principal, seladas pelo Folhelho-Selo, entre as quais destaca a Acumulação Principal, com cerca de 800 m de espessura de zona de gás. Os estudos envolveram modelagem petrofísica 1D das pressões e modelagem histórica 1D de parâmetros tectonossedimentares. Objetivou-se, assim, quantificar as pressões de poros; verificar se elas estão relacionadas à evolução tecnossedimentar e sugerir as causas prováveis da sobrepressão. A modelagem petrofísica forneceu curvas de pressões de sobrecarga (PS), pressão hidrostática (PH) e pressão de poros (PP) a partir de perfis elétricos de poços. A modelagem histórica forneceu curvas de subsidência, taxas de sedimentação, fluxo térmico, temperatura e pressões de poros ao longo do tempo. Análises complementares foram realizadas a partir de dados geoquímicos e de mineralogia do Folhelho-Selo. Foi possível caracterizar as pressões anormais nos perfis e, com razoável confiabilidade, estabelecer a distribuição estratigráfica e espacial das ZPAs existentes na área. Na Sequência K90 foi constatada uma ZPA Principal e uma ZPA Secundária, enquanto nas sequências mais antigas (K70, K82-86 e K88) identificaram-se zonas de menor importância e ocorrência localizada (ZPA-2 e ZPA-3). A ZPA Principal engloba a Acumulação Principal e apresenta gradiente de pressão de poros (GPP) de até 12,6 ppg na zona de gás e 11,7 ppg na zona de água, superiores ao gradiente de pressão hidrostática (GPH), cujos valores variam entre 8,5 ppg e 9,5 ppg. A deposição da K90 ocorreu durante importante período de atividade tectônica e taxas de sedimentação de até 300 m/Ma, sendo submetida a fluxos térmicos de até 100 mW/m2 e temperaturas superiores a 140 oC ao longo do tempo. Não foi identificada uma relação entre a sobrepressão da ZPA Principal e a evolução tectonossedimentar da área ou com as características geoquímicas e minerais do Folhelho-Selo. A ocorrência de gás acumulado é o principal elemento que resultou na ZPA Principal, pois o gás elevou GPP da zona de gás em relação ao GPP do aquífero. Além disso, a coexistência de gás e água deve ter reduzido a condutividade hidráulica do Folhelho-Selo e retardado a equalização das pressões com o meio hidrostático, contribuindo com a elevação do GPP no aquífero. Camadas menos permeáveis internas ao Folhelho-Selo e ao Reservatório Principal, além de falhas selantes, reduziram ainda mais o fluxo de fluidos, contribuindo com a elevação das pressões de poros. A migração de fluidos pressurizados, a partir de níveis inferiores, também pode ter contribuído com o aumento das pressões de poros na ZPA Principal. / Pore pressures have been studied through wells located in a central area of the Santos Basin, Brazil, where Overpressured Zones (ZPA) are characterized by abnormally high PP. Special attention was given to the K90 Depositional Sequence, Santonian to Campanian age, constituted by the Juréia and Itajaí-Açu formations, which is composed by pelitic rocks (Shale-Seal) and sandstones (Main Reservoir). The study area is about 1900km2 large, located about 120km far from the São Paulo State coast, and has gas accumulations in the Main Reservoir sealed by Shale-Seal, among which the Main Accumulation stands out, with about 800 m of gas zone thickness. The studies were carried out by 1D petrophysical pressure modeling and 1D historical modeling, aiming to quantify pore pressures and verify whether they are related to tectonossedimentary evolution and to suggest probable causes for overpressure in the area. The petrophysical pressure modeling provided overburden pressure (PS), hydrostatic pressure (PH) and pore pressure (PP) curves from electric well profiles. Historical modeling provided total and tectonic subsidence, sedimentation rates, heat flow curves, temperature and pore pressures over the geological time. Further analyses were carried out from geochemical and mineralogy data from the Shale-Seal. It was possible to characterize the abnormal pressures in log profiles and, with reasonable reliability, to establish the stratigraphic and spatial distribution of the ZPAs in the area. A Main ZPA and a Secondary ZPA were detected in the K90 Sequence, whereas zones of minor importance and localized occurrence were identified, named ZPA-2 and ZPA-3, were detected in the older sequences (K70, K82-86 and K88). The Main ZPA encompass the Main Accumulation and presents a pore pressure gradient (GPP) up to 12,6 ppg in the gas zone and up to 11,7 ppg in the water zone, too much larger than hydrostatic pressure gradient (GPH), whose values range from 8,5 ppg and 9,5 ppg. The K90 was deposited during a period of huge tectonic activity, with sedimentation rates up to 300 m/My and has been submitted up to 100 mW/m2 of heat flow and temperatures above 140 oC through the time. It was not realized a relation between the occurrence of overpressure and the tectonossedimentary evolution of the area or with the geochemical and mineral characteristics of the Shale-Seal. The occurrence of accumulated gas is the main element that resulted in the Main ZPA, because the gas raised GPP of the gas zone in relation to the GPP of the aquifer, which raised the GPP of the gas zone in relation to the aquifer’s GPP. Besides that, the coexistence of gas and water must have reduced the hydraulic conductivity of the Shale-Seal and retarded the equalization of the pressures with the hydrostatic medium, contributing to raising the aquifer’s GPP. Less permeable layers, internal to Shale-Seal, and sealing faults further reduced the flow of fluids, contributing to the elevation of pore pressures. The migration of pressurized fluids, from lower levels, may also have contributed to increased pore pressures in the Main ZPA.

Résumé Les processus hydrothermaux affectent l'ensemble des domaines océaniques et contrôlent efficacement leur régime thermique. Cependant, les études de flux de chaleur à l'échelle globale conduisent à des interprétations parfois en contradiction avec les études locales. Il est donc essentiel de comparer les effets de l'hydrothermalisme dans différents contextes régionaux. Dans cette optique, nous avons étudié le rôle de l'hydrothermalisme sur le régime thermique d'un domaine océanique jeune (en Atlantique) et d'une marge continentale jeune (Sud Baléares). Pour cela, nous avons quantifié les transferts et pertes de chaleur et de matière en utilisant des traceurs thermiques (mesures du flux de chaleur) et des traceurs chimiques (analyse des fluides interstitiels). Le domaine océanique jeune se situe dans l'océan Atlantique sur le premier segment au sud de la faille transformante Oceanographer. Les faibles valeurs du flux de chaleur indiquent que les circulations hydrothermales, induites par les nombreux affleurements, extraient d'importantes quantités de chaleur de la croûte. La composition de l'eau interstitielle est similaire à l'eau de mer, indiquant un temps de résidence faible de l'eau dans le socle. Nous avons identifié que la rugosité du plancher océanique est un des paramètres majeurs qui contrôlent l'efficacité de ces circulations de fluides. Ce relief à petite échelle a été comparé à d'autres régions où l'efficacité des processus hydrothermaux avait préalablement été discutée. Nous en avons déduis une relation empirique qui relie la fraction du flux de chaleur à ce relief. Sur la marge Sud des Baléares, les processus hydrothermaux semblent plus restreints car leur impact thermique est plus local. Sur la pente continentale, des contrastes importants du flux de chaleur ont été mis en évidence. Ils suggèrent des circulations hydrothermales controlées par la présence de nombreux monts volcaniques. Cependant, la chimie des fluides reste proche de celle de l’eau de mer et ne permet pas de confirmer ces observations. En revanche, les processus hydrothermaux sont limités dans le bassin par les épais dépôts de sédiments. La chimie des fluides indique la présence de saumures résiduelles et leur simple diffusion vers la surface. Les valeurs du flux de chaleur sont perturbées par les contrastes de conductivité thermique induits par la présence de diapirs de sel ou du socle. Dans les deux zones d’étude, les circulations de fluides sont liées à la présence de structures basaltiques fracturées dont la perméabilité est supérieure de plusieurs ordres de grandeur à celle des sédiments alentours. La rugosité initiale du plancher océanique et le taux de sédimentation contrôlent la tranche d’âge durant laquelle la croûte reste connectée à l’océan. En revanche, les circulations sont rapidement inhibées sur les marges par les apports importants de sédiments venant du continent proche. Cette conclusion est contrebalancée par d’autres événements pouvant survenir sur les marges telles que le volcanisme ou la tectonique active. / Hydrothermal processes affect all oceanic domains therby controlling their thermal regime. At global scale, heat flow studies may lead to different interpretations than local studies. Comparing hydrothermal effects in different local contexts is essential to overcome this scale- issues. To do so, we studied the hydrothermal impact on the thermal regimes of a young oceanic domain (Atlantic Ocean) and a young margin (South Balearic). We quantified heat and matter transfers and heat losses with heat flow measurements and pore water chemical analyses. The young oceanic domain is situated on the first segment south of Oceanographer transform fault in the Atlantic Ocean. The low heat flow values indicate that hydrothermal circulations, conveyed by numerous outcrops, extract a lot of crustal heat. The composition of water in pores is similar to that of seawater. This points to a short residence time of water in the basement. We identified that the ruggedness of the seabed is one of the key parameters that control the fluid circulation efficiency. This small scale relief was compared to others regions where hydrothermal processes have already been debated. We deduced an empirical relation which links the fraction of the conductive heat flow to this relief. On the Southern Balearic margin, hydrothermal processes appear to be more limited because of their more local thermal impact. On the continental slope, great heat flow contrasts are highlighted. They suggest that hydrothermal circulation is controlled by numerous volcanic mounts. On one hand, pore fluid chemistry remains close to seawater composition and does not allow confirming these observations. On the other hand, hydrothermal processes in the basin are limited by thick sediment deposits and pore fluid chemistry indicates residual brines and their diffusion towards the surface. Heat flow values along the Southern Balearic margins are perturbed by thermal conductivity contrasts induced by salt diapirs or basement topography. In both study areas, fluid circulations are linked to fractured basaltic structures with a much larger permeability than the surrounding sediments. The seabed’s initial ruggedness and the sedimentation rate control the age range during which the crust is connected to ocean. Nevertheless, fluid circulations cease quickly due to important sediment flows from the nearby continent. This conclusion is partially offset by other events that may occur on the margins such as volcanism or active tectonic.

The X-Ray imaging technology opened a new branch of science in which the internal porous structure can be captured and the reconstructed volume can be used for fluid flow simulations and structural measurements. However, there is still the question of how the internal structure of the pore space impacts in the observed simulations. A way to characterize this internal structure is by simplifying it into well-defined elements and the interaction between them, describing it as a network. The interaction between elements are the edges of the network and elements are the nodes. This opens the possibility of applying complex network theory on the characterization of porous media which has proven to give powerful insights into how the structure of porous materials influences on the dynamics of the permeating fluid. The problem with this description is in definition of the basic elements that will compose the network, since there isnt a consensus on this definition. The purpose of this work is to provide a method to analyze μCT data through networks in which the separation of the space is done in a semi-continuous method. The recovering of the pores local geometry is captured through a network analysis method of centrality, instead of a geometrical definition. This way the intrinsic morphology of the samples is what governs the pore-space separation into different entities. The method developed is based on the network extraction method Max Spheres Algorithm (MSA). The volumetric data is recovered through a network composed by sphere cells. The output of this process are two distinct networks: the complete volume network and a network which represents the variation of the channels diameter. These networks give unbiased real information on pore connectivity and can provide important data to better understand the morphology and topology of the samples. This method was successfully applied to samples of Berea sandstone, Estaillades carbonate, and to characterize the morphology of wormholes. Wormhole is the denomination of the channel formed after the application of an acid treatment as a stimulation procedure of an oil reservoir, a method of EOR (Enhanced oil recovery). This treatment consists of a reactive fluid flow injected in the inner rock of the reservoir, which creates a preferential path (wormhole) that optimizes the extraction of the hydrocarbon fluids. / A microtomografia de raios-X permitiu a evolução de uma nova área da ciência aplicada a meios porosos: a Rocha Digital. Através desta técnica, todo o espaço poroso é recuperado, e é possível entender a dinâmica do fluido que o permeia através de simulações computacionais. No entanto, ainda há a questão de como a estrutura do meio influencia nos resultados observados. Entender questões como connectividade e clusterização de regiões podem dar informações valiosas sobre como a origem do meio poroso influencia na dinâmica do fluido que o permeia. Esta avaliação do meio é possível através da simplificação do mesmo em uma rede de conexão de elementos básicos e as interações entre estes. O problema com a descrição do meio poroso em uma rede de conexão é que não existe um consenso na definição destes elementos básicos. O propósito deste trabalho foi encontrar uma maneira de descrever o meio que fosse aplicável a qualquer litologia, e que se aproximasse ao máximo dos dados extraídos pela micro tomografia para a análise das topologias de diferentes rochas através de teoria de redes complexas.Para isso, utilizamos o algoritmo robusto de extração de redes de poros, esferas máximas, como base para dividir o espaço-poroso em células esféricas. Desta forma, todo o volume do espaço poroso observado através da micro tomografia é recuperado e descrito em uma rede de conexão. O resultado final do método aplicado é uma rede que descreve o meio completo e uma rede que descreve o eixo medial das interconexões entre poros. A geometria local dos poros é recuperada através de um critério de centralidade de rede, assim a separação é governada pela morfologia intrínseca das amostras, ao invés de fatores geométricos.Desta forma podemos analisar o efeito da tortuosidade real do meio, assim como a interconexão entre poros, com relação a permeabilidade do meio.O método se mostrou eficaz na análise de rochas com diferentes litologias: arenito (Berea) e carbonato (Estaillades). O método também foi aplicado na avaliação da estrutura de canais formados pelo processo de acidificação de rochas (wormholes).