Hohenheim, Univ., Diss., 2005.

L'état de surface est l'un des paramètres les plus importants pour déterminer la biocompatibilité d'un dispositif médical implantable, tout changement à la surface une fois en contact avec les tissus corporels peut avoir un impact sur la réponse biologique (cytotoxicité, inflammation, irritation, thrombose ... etc.). Pendant le stockage, l’exsudation des additifs peut se produire à la surface des polymères et modifier leurs propriétés. Dans cette étude, nous utilisons du polyuréthane à base de cathéter (Pellethane®), en raison de ses nombreuses applications dans le domaine des dispositifs médicaux, pour évaluer l'impact d’exsudation des additifs sur la biocompatibilité. L'impact des traitements de stérilisation et d'oxydation sur le phénomène d’exsudation a été étudié. L'étude a été réalisée sur du polyuréthane utilisé dans la fabrication de cathéters sur lesquels l’exsudation de cristaux d’additifs a déjà été observée. La stérilisation par rayonnements ionisants (bêta, gamma) a été réalisée sur ce matériau et les échantillons ont été soumis à différents types de processus d'oxydation (UV, H2O2 et action des macrophages). La viabilité des cellules endothéliales a été étudiée. Une évaluation préliminaire de l'hémocompatibilité a été réalisée par la mesure de l'hémolyse du sang total, ainsi que par l'adhésion des plaquettes en contact avec les différents échantillons de PU. L'étude de la production pro-inflammatoire d'IL-alpha; et de TNF-alpha; par des macrophages en contact avec des échantillons a également été rapportée. / Surface state is one of the most important parameter determining the biocompatibility of animplantable medical device, any change on the surface once in contact with body tissues canimpact the biological response (Cytotoxicity, inflammation, irritation, thrombosis …etc). During storage, the blooming of additives may occur on the surface of polymers and modify their properties. In this study, we use (Pellethane®) catheter-based polyurethane, because of its many applications in the field of medical devices, to evaluate the impact of additives blooming on the biocompatibility. The impact of sterilizing and oxidation treatments on blooming was studied. The study was realized on polyurethane used in the fabrication of catheters on which the blooming of antioxidant crystals has been previously observed. Sterilization by ionizing radiations (beta, gamma) was performed on this material and samples were submitted to different kinds of oxidation process (UV, H2O2 and macrophages action). Endothelial cells viability was studied. A preliminary haemocompatibility evaluation was performed through the measurement of whole blood hemolysis, as well as platelet adhesion in contact with the different PU samples. The study of the pro-inflammatory IL-alpha; and TNF-alpha; production by macrophages in contact with samplesis also reported.

Les travaux réalisés lors de cette thèse s’effectuent dans le cadre du projet FIXAPIN. Ce projet, financé par la région Nouvelle Aquitaine, est mené en collaboration avec différentes entreprises (Gascogne Bois, Bardage Bois Neoclin, Lesbats Scieries d’Aquitaine, Scierie Labadie et FPBOIS) spécialisées dans le domaine du sciage du bois de pin maritime et l'Institut technologique FCBA. L’objectif du projet est de limiter voire d’empêcher l’exsudation de la résine généralement observée sur la surface des planches de bois de pin maritime utilisées en extérieur comme bardage. L’exsudation de la résine est un frein important à l’utilisation de ce bois en extérieur et ces recherches s’inscrivent dans une démarche d’amélioration continue de la qualité des produits de la filière du pin maritime.Le bois de pin maritime peut présenter un taux de résine supérieur à 10 % de sa masse. La résine est constituée d’environ 70 % de colophane (fraction solide) et de 30 % d’essence de térébenthine (fraction liquide et volatile). À la suite d’essais préliminaires, les recherches réalisées lors de cette thèse se sont concentrées sur l’optimisation du cycle de séchage du bois afin de fixer la résine dans les planches. Les propriétés thermiques de la résine associée à des analyses physico-chimiques ont été étudiées afin de mettre en place des procédures de séchage optimisées ayant pour but d’augmenter la température de ramollissement de la résine à un seuil supérieur à la température maximum atteignable par un bardage extérieur.Les résultats ont permis de démontrer l’efficacité d’un séchage/traitement thermique du bois à haute température (> 120 °C) permettant d’envisager la poursuite de ces travaux aux échelles pilotes puis industrielles. De plus, des séchages longs à basse température (< 60 °C) peuvent également représenter une voie prometteuse concernant le séchage du bois en séchoir traditionnel. / The work realised in the context of this thesis is carried out within the FIXAPIN project. This project, funded by the Nouvelle Aquitaine council, is carried out in collaboration with several companies (Gascogne Bois, Bardage Bois Neoclin, Lesbats Scieries d'Aquitaine, Scierie Labadie and FPBOIS) specialized in the sawing of maritime pine wood and the FCBA Technological Institute.The aim of the project is to limit or even to prevent the exudation of the resin generally observed on the surface of maritime pine wood boards used outdoors as wood siding. The resin exudation is a major constraint to the external use of this wood and this research project is part of a continuous improvement process of the maritime pine products quality.Maritime pine wood can have a resin amount greater than 10% of its mass. The resin consists approximately of 70% rosin (solid fraction) and 30% turpentine (liquid and volatile fraction). Based on preliminary tests, the research carried out during this thesis focused on optimizing the wood drying process in order to fix the resin in the wood boards. The thermal properties of the resin associated with physico-chemical analyses were studied in order to implement optimized drying procedures to increase the resin softening temperature to a threshold higher than the maximum temperature attainable by an exterior siding.The results have demonstrated the effectiveness of drying / heat treatment of wood at high temperature (> 120 ° C) to allow the pursuit of this work at pilot than industrial scales. Furthermore, long drying at low temperatures (<60 ° C) may also be a promising approach regarding the wood drying process in traditional kilns.

Konstanz, Univ., Diplomarb., 2004.

L'exsudation racinaire est connue pour avoir une influence sur le fonctionnement des communautés microbiennes, en particulier celles impliquées dans le cycle de l'azote (Haichar et al, 2012). Elle est liée à la physiologie de la plante, cette dernière pouvant être évaluée via les traits fonctionnels végétaux, permettant une classification des plantes en fonction de leur performance dans leur environnement. Ainsi, nous pouvons distinguer d'une part les espèces exploitatrices, avec une efficience de la photosynthèse élevée et une acquisition rapide de l'azote dans les sols, et d'autre part les plantes conservatrices, possédant des caractéristiques contraires (Aerts & Chapin, 1999) et des plantes intermédiaires dont les caractéristiques sont intermediaires.L'objectif de ces travaux de thèse est de déterminer l'influence de la stratégie de gestion des ressources de 6 poacées, réparties le long d'un gradient de stratégie de gestion des ressources, allant de stratégies conservatrices (Sesleria caerulea et Festuca paniculata), intermédiaires (Antoxanthum odoratum, Bromus erectus) à des stratégies exploitatrices (Dactylis glomerata et Trisetum flavescens), sur la diversité et le fonctionnement des communautés totales et dénitrifiantes. I) Dans un premier temps nous avons étudié le lien entre la stratégie de gestion de ressources des plantes et la quantité d'exsudats racinaires dans le sol adhérent aux racines (SAR). Nous avons ensuite déterminé l'influence de la quantité d'exsudats racinaire sur les activités microbiennes potentielles des communautés microbiennes du SAR (respiration et dénitrification potentielles), puis par une approche ADN-SIP (Stable Isotope Probing) couplée à du séquençage haut-débit, l'influence de l'exsudation racinaire sur la structure et la diversité des communautés bactérienne colonisant le SAR et le système racinaire. II) Dans un second temps, nous avons étudié le lien entre la stratégie de gestion des ressources des plantes et la nature des exsudats racinaires libérés au niveau du SAR et présents dans les extraits racinaires en analysant les profils des métabolites primaires chez Festuca paniculata, Bromus erectus et Dactylis glomerata, représentant respectivement des stratégies de gestion des ressources conservative, intermédiaire et exploitatrice / Root exudation is known to influence microbial communities functioning, in particular those involve in nitrogen cycle. (Haichar et al, 2012). It’s linked to plant physiology, which can be evaluated with functional traits, allowing a plant distribution in function of their performance in their environment. Thus, we can distinguish competitive species, with higher photosynthetic capacity and rapid rates of N acquisition, conservative species with the opposite characteristics (Aerts & Chapin, 1999) and intermediate plants, with intermediate characteristics.The objective of this work is to determinate the influence of nutrient management strategiy of 6 poaceae, along a strategies gradient from conservative strategy (Sesleria caerulea and Festuca paniculata), intermediate (Antoxanthum odoratum and Bromus erectus) to competitive strategy (Dactylis glomerata and Trisetum flavescens), on diversity and functioning of total and denitrifying communities.I) Firstly, we studied the link between the plant nutrient management strategy and the root exudates quantity in the root adhering soil (RAS). Then, we determined the influence of the rate of root exudation on potential microbial activities (respiration and denitrification), and with a DNA-SIP (Stable Isotope Probing) approach coupled to high-throughput sequencing, the influence of root exudation on the bacterial structure and diversity of communities colonizing the RAS and the root system. II) Secondly, we studied the link between the plant nutrient management strategy and the nature of molecules exuded in RAS and present in root extracts by analyzing primary metabolites profile to Festuca paniculata, Bromus erectus and Dactylis glomerata, respectively a conservative, an intermediate and a competitive plant. Then, we determined the influence of primary metabolites profile of each plant on semi-real denitrification of communities colonizing RAS of plants. III) Finally, an mRNA-SIP approach is in progress to determine the influence of exuded metabolites on active bacterial communities functioning and the expression of genes involved in denitrification process in RAS and root system. Our results show an influence of the nutrient management strategy on the rate of carbon exudation, the competitive plants exuding more than conservatives ones.

Le chauffage des matériaux cosmétiques peut provoquer une exsudation de surface sous la forme de petites gouttes puis un retrait des gouttes associé à un processus de recristallisation. Des méthodes rhéologiques et de diffusion multiple de la lumière ont permis une étude des effets d’exsudation et de recristallisation en fonction de la température de chauffage, du vieillissement et de la plasticité du matériau. Des simulations numériques et un modèle phénoménologique basés sur la prolifération de fissures métastables et la croissance hors équilibre d’amas de défauts liquides susceptibles de crever la surface permettent de rendre compte des effets d’exsudation et de recristallisation variables selon la plasticité de la matrice semi-cristalline et la teneur en huile dans le matériau soumis à une perturbation thermique. / The heating of cosmetic materials can generate an external sweating phenomenon shown by the formation of droplets, followed by a withdrawal of the droplets due to the recrystallization process. Rheological methods and light scattering allowed to study the effects of sweating and re-crystallization in term of heating temperature, aging, and material’s elasticity. Numerical simulations and a phenomenological model based on the multiplication of metastable cracks and the growth outside of equilibrium state of liquid default pits able to burst the surface proves the sweating effects and the re-crystallization variable depending on the semi-crystalline matrix and the percentile of oil in the material under thermal fluctuation.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O trabalho teve como escopo a caracterização geológica, em termos estruturais e estratigráficos, do sistema petrolífero responsável pela ocorrência de óleos encontrados na Formação Rio Bonito, na região carbonífera de Santa Catarina. Atualmente, especula-se que a assinatura geoquímica destes óleos relaciona-se à Formação Irati associado a um modelo não convencional de geração, vinculando a maturação térmica à intrusão de diabásio, devido a um soterramento insuficiente da rocha geradora. Como a Formação Irati encontra-se posicionada estratigraficamente acima da Formação Rio Bonito, o sistema está associado a um forte controle estrutural para o modelo de migração. A preparação de um mapa geológico integrado para a área de estudo envolvendo dados geológicos de campo, dados aeromagnetométricos e informações de furos de sondagem permitiu um entendimento mais aprofundado do arcabouço tectônico-estratigráfico da região. Seções geológicas mostraram a presença de falhas de grandes rejeitos que promoveram um sistema de Horsts e Grabens relacionados às NE-SW e secundariamente a falhas E-W, que permitiram a colocação da Formação Irati em contato lateral ou em um posicionamento abaixo da Formação Rio Bonito. A partir das seções cronoestratigráficas elaboradas foi possível reconhecer prováveis selos, trapas estratigráficos e estruturais, associados ao sistema petrolífero Irati-Rio Bonito. A análise geoquímica (isótopos e biomarcadores) dos óleos coletados na Formação Rio Bonito apontaram que os mesmos estão associadas aos folhelhos do Membro Assistência da Formação Irati, por possuírem uma razão pristano/fitano menor que 1, gamacerano, e a presença de isoprenóides pentametileicosano (i-25) e esqualano (i-30). A partir de análises geoquímicas realizadas em extratos orgânicos extraídos de folhelhos da Formação Irati intrudidos por diabásio, obteve-se valores da relação entre biomarcadores correspondentes e valores de Ro que indicam que foi alcançado o pico de geração de óleo. Contudo, não há registro na área de estudo de um soterramento suficiente que favorecesse essa situação, levando-nos, assim, a acreditar em um modelo de geração não convencional, por meio da intrusão de diabásio nas rochas geradoras. O arcabouço estrutural e os óleos estudados na região sugerem um processo migratório de sudoeste para o nordeste, ao longo de um sistema de falhas NE-SW, encontradas na região, que foram geradas anteriormente ou concomitantemente ao derrame basáltico associado à Formação Serra Geral. / The work aims at the geological characterization of the structural and stratigraphic system responsible for the petroleum oils that occurs in Rio Bonito Formation, in the coalfield of Santa Catarina. Currently, it has been speculated that the geochemical signature of this oil is related to the Irati Formation associated with an unconventional model generation, by the thermal maturation of diabase intrusion, due to source rock insufficient burial. As the Irati is stratigraphically positioned above the Rio Bonito, the system is associated to a strong structural control for the migration model. The preparation of a geological map for the area that includes the geological field data, airborne magnetic data and drillhole information has enabled to a deep understanding of tectonic-stratigraphic region. Geological cross-sections showed the presence of faults that caused a system of grabens and horsts related to NE-SW faults and secondarily E-W that may have positioned the Irati Formation sidewise or below the Rio Bonito Formation. Cronostratigraphic sections made it possible to recognize seals, structural and stratigraphic traps associated with the petroleum system Irati-Rio Bonito. The geochemical analysis of the oil (isotopes and biomarkers) collected at the Rio Bonito Formation, indicated that they are associated with the Assistência Member shales (Irati Formation), by having the ratio pristane / phytane lower than 1, gammacerane, and the presence of isoprenoid pentametileicosano (i -25) and squalane (i-30). Geochemical analysis on organic extracts taken from Irati shales intruded by diabase, revealed Ro values that indicated peak oil generation was reached. However, there are no records in the study area about a sufficient burial favoring this situation, leading us, in this case, to believe in an unconventional generation model through the diabase intrusion in the source rocks. The structural and oil studied in the region suggest the existence of a migratory process from southwest to northeast along the NE-SW fault system that was generated previously the basalt floods associated with the Serra Geral Formation.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O trabalho teve como escopo a caracterização geológica, em termos estruturais e estratigráficos, do sistema petrolífero responsável pela ocorrência de óleos encontrados na Formação Rio Bonito, na região carbonífera de Santa Catarina. Atualmente, especula-se que a assinatura geoquímica destes óleos relaciona-se à Formação Irati associado a um modelo não convencional de geração, vinculando a maturação térmica à intrusão de diabásio, devido a um soterramento insuficiente da rocha geradora. Como a Formação Irati encontra-se posicionada estratigraficamente acima da Formação Rio Bonito, o sistema está associado a um forte controle estrutural para o modelo de migração. A preparação de um mapa geológico integrado para a área de estudo envolvendo dados geológicos de campo, dados aeromagnetométricos e informações de furos de sondagem permitiu um entendimento mais aprofundado do arcabouço tectônico-estratigráfico da região. Seções geológicas mostraram a presença de falhas de grandes rejeitos que promoveram um sistema de Horsts e Grabens relacionados às NE-SW e secundariamente a falhas E-W, que permitiram a colocação da Formação Irati em contato lateral ou em um posicionamento abaixo da Formação Rio Bonito. A partir das seções cronoestratigráficas elaboradas foi possível reconhecer prováveis selos, trapas estratigráficos e estruturais, associados ao sistema petrolífero Irati-Rio Bonito. A análise geoquímica (isótopos e biomarcadores) dos óleos coletados na Formação Rio Bonito apontaram que os mesmos estão associadas aos folhelhos do Membro Assistência da Formação Irati, por possuírem uma razão pristano/fitano menor que 1, gamacerano, e a presença de isoprenóides pentametileicosano (i-25) e esqualano (i-30). A partir de análises geoquímicas realizadas em extratos orgânicos extraídos de folhelhos da Formação Irati intrudidos por diabásio, obteve-se valores da relação entre biomarcadores correspondentes e valores de Ro que indicam que foi alcançado o pico de geração de óleo. Contudo, não há registro na área de estudo de um soterramento suficiente que favorecesse essa situação, levando-nos, assim, a acreditar em um modelo de geração não convencional, por meio da intrusão de diabásio nas rochas geradoras. O arcabouço estrutural e os óleos estudados na região sugerem um processo migratório de sudoeste para o nordeste, ao longo de um sistema de falhas NE-SW, encontradas na região, que foram geradas anteriormente ou concomitantemente ao derrame basáltico associado à Formação Serra Geral. / The work aims at the geological characterization of the structural and stratigraphic system responsible for the petroleum oils that occurs in Rio Bonito Formation, in the coalfield of Santa Catarina. Currently, it has been speculated that the geochemical signature of this oil is related to the Irati Formation associated with an unconventional model generation, by the thermal maturation of diabase intrusion, due to source rock insufficient burial. As the Irati is stratigraphically positioned above the Rio Bonito, the system is associated to a strong structural control for the migration model. The preparation of a geological map for the area that includes the geological field data, airborne magnetic data and drillhole information has enabled to a deep understanding of tectonic-stratigraphic region. Geological cross-sections showed the presence of faults that caused a system of grabens and horsts related to NE-SW faults and secondarily E-W that may have positioned the Irati Formation sidewise or below the Rio Bonito Formation. Cronostratigraphic sections made it possible to recognize seals, structural and stratigraphic traps associated with the petroleum system Irati-Rio Bonito. The geochemical analysis of the oil (isotopes and biomarkers) collected at the Rio Bonito Formation, indicated that they are associated with the Assistência Member shales (Irati Formation), by having the ratio pristane / phytane lower than 1, gammacerane, and the presence of isoprenoid pentametileicosano (i -25) and squalane (i-30). Geochemical analysis on organic extracts taken from Irati shales intruded by diabase, revealed Ro values that indicated peak oil generation was reached. However, there are no records in the study area about a sufficient burial favoring this situation, leading us, in this case, to believe in an unconventional generation model through the diabase intrusion in the source rocks. The structural and oil studied in the region suggest the existence of a migratory process from southwest to northeast along the NE-SW fault system that was generated previously the basalt floods associated with the Serra Geral Formation.

Les plantes se distribuent dans des habitats présentant une disponibilité variable en nutriment et s'y adaptent en ajustant leur taux de croissance relatif. Les espèces adaptées aux habitats infertiles, affichent un taux de croissance plus faible que celles adaptées aux habitats fertiles. Les adaptations expliquant cette distribution ont été identifiées, premièrement, au niveau des feuilles. Un fort taux de fixation du carbone et d’allocation de ce dernier à la croissance sont favorisés en investissant davantage dans des tissus foliaires contenant des enzymes photosynthétiques riches en azote, par rapport aux tissus structuraux riches en carbone. Inversement, les feuilles favorisant une croissance lente présentent une plus grande quantité de tissus structuraux que de tissus riches en enzymes photosynthétiques, ce qui prolonge leur longévité, mais restreint leur taux d'assimilation du carbone. Étant donné que les adaptations foliaires dépendent de l'utilisation des nutriments acquis par les racines, les adaptations de ces dernières sont essentielles pour comprendre la distribution des plantes. Le fonctionnement des racines est influencé par les mêmes variations dans le ratio entre les tissus à forte teneur en protéines riches en azote et les tissus structuraux. Les fortes valeurs de ce ratio améliorent l’acquisition des nutriments et soutiennent une croissance rapide, tandis que les faibles valeurs prolongent la longévité des racines, mais restreignent leur taux d'acquisition. Cependant, les racines doivent également explorer le sol dû à la mobilité limitée des nutriments. Cette fonction est réalisée en établissant des relations symbiotiques avec des champignons ou par l'allongement de leurs racines. Cependant, contrairement aux adaptations foliaires, la relation entre ces adaptations racinaires et la disponibilité des nutriments présente des résultats contradictoires. De plus, ces adaptations n'influencent pas l'acquisition des nutriments non directement disponibles, comme les nutriments organiques, qui peuvent représenter une proportion importante des nutriments du sol. Cela limite notre compréhension de la nutrition des plantes et entrave notre compréhension des mécanismes expliquant leur distribution. Afin de mieux comprendre la nutrition des plantes, des feuilles et des racines furent échantillonnées le long de gradients de fertilité. Les résultats ont montré que l'utilisation de nutriments organiques par le biais d'enzymes hydrolytiques augmentait à mesure que la fertilité des sols diminuait. De plus, une forte corrélation entre cette adaptation et les adaptations racinaires liées aux taux d'acquisition des nutriments a été observée, mais aucune corrélation n'a été constatée avec celles liées à l'exploration du sol. En revanche, dans un autre système d'étude, les résultats ont indiqué que les adaptations racinaires liées à l'exploration du sol, plutôt que celles associées aux taux d'acquisition des nutriments, s'alignaient avec la variation de la disponibilité des nutriments et se coordonnaient avec les adaptations foliaires qui permettent d’expliquer en partie la distribution des plantes. Dans l'ensemble, ces études ont approfondi notre compréhension de la nutrition des plantes et ont révélé différentes relations entre la variation de la disponibilité des nutriments et les adaptations racinaires influençant l'acquisition des nutriments et l'exploration du sol. Cela suggère qu’une généralisation des adaptations racinaires répondant systématiquement aux demandes nutritionnelles des feuilles est peu probable. / Plants are distributed across habitats of varying nutrient availability and adapt by adjusting, notably, their relative growth rates. Species adapted to nutrient-poor habitats exhibit lower growth rates than those adapted to nutrient-rich habitats. The adaptations explaining this distribution have been identified, first and foremost, at the leaf level. Leaves promoting rapid growth enhance net carbon assimilation by investing more in nitrogen-rich photosynthetic enzymes compared to carbon-rich structural tissues. This extends their lifespan, enhances their nutrient-use efficiency but limits carbon assimilation. Given that foliar adaptations depend on the utilization of nutrients acquired by roots, root adaptations are essential to understanding plant distribution. Plants possess also the ability to modify the ratio between nitrogen-rich protein tissues and carbonrich structural tissues in their roots. Similarly to leaf functioning, increasing this ratio enhances the efficiency of nutrient acquisition while minimizing carbon investment, enabling optimal carbon allocation for growth. On the other hand, they can decrease this ratio to prioritize nutrient conservation, which extends their longevity but restricts nutrient acquisition rate. However, roots must also explore the soil due to the limited mobility of nutrients. Soil exploration is achieved by establishing symbiotic relationships with fungi or through the elongation of their roots. Unlike leaf adaptations, the relationship between these root adaptations and nutrient availability yields contradictory results. Additionally, these adaptations do not directly influence the acquisition of non-readily available soil nutrients, such as organic nutrients, which can represent a significant proportion of the total nutrient pool. Thus, our understanding of plant nutrition is limited, impeding our understanding of the mechanisms explaining their distributions. To contribute to an enriched understanding of plant nutrition, leaves and roots were sampled along strong fertility gradients. The results revealed an increase in the utilization of organic nutrients through hydrolytic enzymes as the availability of directly accessible nutrients declined. Furthermore, a strong correlation between this adaptation and root adaptations related to nutrient acquisition rates has been observed, but no correlation was found with adaptations related to soil exploration. On the other hand, in another study system, the results indicated that root adaptations related to soil exploration, rather than those associated with nutrient acquisition rates, aligned with the variation in nutrient availability and coordinated with foliar adaptations influencing net carbon assimilation. As a result, a high degree of mycorrhizal symbiosis was associated with leaves favoring rapid growth in fertile soil. Overall, roots displaying a high density of structural tissues and a high degree of symbiotic association were associated with fertile soil across two different study systems. Altogether, these results have deepened our understanding of plant nutrition and revealed different possible relationships between nutrient availability variation and root adaptations influencing nutrient acquisition and soil exploration. This suggests that generalizing root adaptations that consistently meet the nutrient demands of leaves is unlikely.