The budding yeast Saccharomyces cerevisiae has been an invaluable model organism in contributing to the current understanding of cellular biology, owing mainly to its highly tractable genetic system and the completion of its genome sequencing in 1996. Indeed, these bolstered the development of novel methods that have provided great insights into genetic and protein networks in human cells. With the large collection of datasets, S. cerevisiae also became an ideal platform for investigating the mechanism of action of novel compounds. The first part of my thesis uses a validated chemogenomic assay to investigate the mechanism of action of structurally related novel DNA-damaging agents, delineating valuable structure-activity relationship in the process. The second part describes the development of a method that uses drug-induced wild-type growth dynamic to characterize novel compounds, which, in combination with the chemogenomic assay, may complement existing high throughput screening experiments to improve the current drug development process.

Ce travail porte sur le développement d’une technique de calorimétrie sans contact pour des écoulements diphasiques. Ces derniers sont réalisés sur la forme d’un train gouttes dans des tubes de taille millimétriques dans des supports isopériboliques. L’idée principale est de coupler la Thermographie Infrarouge et les outils microfluidiques pour proposer une technique adapté de mesure. L’utilisation de la microfluidique rend possible l’utilisation de très faibles volumes réactionnels limitant ainsi tout risque lié à la dangerosité des réactions réalisées au sein des gouttes, l’outil Infrarouge permet de suivre ces écoulements avec grande précision. Les résultats de ces travaux de thèse montrent que l’outil est capable d’estimer des propriétés thermo-physiques des écoulements non réactifs. Ainsi, que de caractériser de réactions chimiques en termes d’enthalpie et cinétique. Finalement cette dernière caractérisation a été comparée aux techniques classiques pour mettre en évidence la précision et les avantages de l’outil développé / This work concerns the development of a non-contact calorimeter for two-phase flow characterization. The biphasic flow is performed under a droplet configuration inside millimetric tubings which are inserted into the isoperibolic chip. The main idea is to combine the Infrared Thermography and microfluidic tools to propose a suitable technique for accurate measurements. Microfluidics enables the use of small reaction volumes thus limiting any risk of dangerous reactions inside droplets, the Infrared tool enables to monitor the thermal signature of these flows with high accuracy. The results of this thesis show that this tool is able to estimate the thermophysical properties of non-reactive flows. Also , it is possible to characterize chemical reactions in terms of enthalpy and kinetics . Finally the latter characterization was compared to conventional techniques to demonstrate the benefits and the precision of the tool.

Background: Collagens of marine origin are applied increasingly as alternatives to mammalian collagens in tissue engineering. The aim of the present study was to develop a biphasic scaffold from exclusively marine collagens supporting both osteogenic and chondrogenic differentiation and to find a suitable setup for in vitro chondrogenic and osteogenic differentiation of human mesenchymal stroma cells (hMSC). Methods: Biphasic scaffolds from biomimetically mineralized salmon collagen and fibrillized jellyfish collagen were fabricated by joint freeze-drying and crosslinking. Different experiments were performed to analyze the influence of cell density and TGF-β on osteogenic differentiation of the cells in the scaffolds. Gene expression analysis and analysis of cartilage extracellular matrix components were performed and activity of alkaline phosphatase was determined. Furthermore, histological sections of differentiated cells in the biphasic scaffolds were analyzed. Results: Stable biphasic scaffolds from two different marine collagens were prepared. An in vitro setup for osteochondral differentiation was developed involving (1) different seeding densities in the phases; (2) additional application of alginate hydrogel in the chondral part; (3) pre-differentiation and sequential seeding of the scaffolds and (4) osteochondral medium. Spatially separated osteogenic and chondrogenic differentiation of hMSC was achieved in this setup, while osteochondral medium in combination with the biphasic scaffolds alone was not sufficient to reach this ambition. Conclusions: Biphasic, but monolithic scaffolds from exclusively marine collagens are suitable for the development of osteochondral constructs.

This master thesis deals with the topic of alternative production of hydrogen as the energy carrier of the future. The primary focus is on the production of hydrogen based on photocatalytical water splitting in the presence of semiconductor materials (especially modified and unmodified TiO2). The aim of the thesis is a synthesis of nanostructured oxide, graphene/graphene oxide particles and its composites, and a study of its structures and photocatalytical properties regarding photolysis of water. Products of the syntheses are described from the point of view of phase composition, surface area and photocatalytical activity. The main output of the thesis is a discussion of the influence of alkaline complex forming reagents on the hydrothermal low-temperature synthesis of biphasic TiO2, and a study of the influence of graphene/graphene oxide modification on photocatalytical activity of biphasic TiO2.

Transition-metal chemistry in ionic liquids (IL) has achieved intrinsic fascination in the last few years. The use of an IL as environmental friendly solvent, offers many advantages over traditional materials synthesis methods. The change from molecular to ionic reaction media leads to new types of materials being accessible. Room-temperature IL have been found to be excellent media for stabilising transition-metal clusters in solution and to crystallise homo- and heteronuclear transition-metal complexes and clusters. Furthermore, the use of IL as solvent provides the option to replace high-temperature routes, such as crystallisation from the melt or gas-phase deposition, by convenient room- or low-temperature syntheses. Inorganic IL composed of alkali metal cations and polynuclear transition-metal cluster anions are also known. Each of these areas will be discussed briefly in this contribution. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Diese Arbeit widmet sich der Untersuchung der dynamischen und strukturellen Eigenschaften sowie des Phasenverhaltens konzentrierter flüssiger Elektrolyte und ihrer Anwendung in Energiespeichern mittels Methoden der statistischen Mechanik und mithilfe atomistischer Molekulardynamik (MD) Simulationen. Zuerst untersuchen wir die Struktur-Eigenschafts-Beziehungen in konzentrierten Elektrolytlösungen wie sie in Lithium-Schwefel (Li/S), durch wir ein MD Simulationsmodell repräsentativer state-of-the-art Elektrolyt-Systeme für Li/S-Batterien bestehend aus Polysulfiden, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) und LiNO 3 Elektrolyten mit jeweils unterschiedlichen Kettenlängen gemischt in organischen Lösungsmitteln aus 1,2-dimethoxyethane and 1,3-dioxolane erstellen. Als Zweites befassen wir uns mit der Phasenseparation, die auftritt, wenn sich die physikalisch-chemischen Eigenschaften flüssiger Gemische voneinander unterscheiden. Diese Systeme bestehen üblicherweise aus einem konzentrierten anorganischen Salz und einer ionischen Flüssigkeit. In dieser Arbeit untersuchen wir eine Vielfalt von hochkonzentrierten wässrigen Elektrolytlösungen, die aus unterschiedlichen Zusammensetzungen von LiCl und LiTFSI bestehen. Daraufhin beantworten wir die Frage, wie unterschiedlich die Komponenten in der wässrigen Lösung gemischt sein sollten, damit eine solche flüssig-flüssig-Phasentrennung stattfinden kann. Als letztes untersuchen wir die Ladungsabschirmung, die ein grundlegendes Phänomen ist, das die Struktur von Elektrolyten im Bulk und an Grenzflächen bestimmt. Wir haben in dieser Arbeit die Abschirmlängen für verschiedene Elektrolyte von niedrigen bis zu hohen Konzentrationen untersucht. / Electrolytes can be found in numerous applications in daily life as well as in scientific research. The increases in demand for energy-storage systems, such as fuel cells, supercapacitors and batteries in which liquid electrolyte properties are critical for optimal function, draw critical attention to the physical and chemical properties of electrolytes. Those energy-storage devices contain intermediate or highly concentrated electrolytes where established theories, like the Debye-Hückel (DH) theory, are not applicable. Despite the efforts to describe the physical properties of intermediate or highly concentrated electrolytes, theoretical atomistic-level studies are still lacking. This thesis is devoted to critically investigate the transport/structural properties and a phase behavior of concentrated liquid electrolytes and their application in energy-storage devices, using statistical mechanics and atomistic molecular dynamics (MD) simulations. Firstly, we investigate the structure-property relationship in concentrated electrolyte solutions in next-generation lithium-sulfur (Li/S) batteries. Secondly, phase separation may exist if the physio-chemical properties of liquid mixtures are very different. Recently, the coexistence phase of two aqueous solutions of different salts at high concentrations was found, called aqueous biphasic systems. We explore a wide range of compositions at room temperature for highly concentrated aqueous electrolytes solutions that consist of LiCl and LiTFSI. Lastly, charge screening is a fundamental phenomenon that governs the structure of liquid electrolytes in the bulk and at interfaces. From the DH theory, the screening length is expected to be extremely small in highly concentrated electrolytes. Yet, recent experiments show unexpectedly high screening lengths in those. This intriguing phenomenon has prompted a new set of theoretical works. We investigate the screening lengths for various electrolytes from low to high concentrations.

[pt] Neste trabalho focamos sobre alguns modelos matemáticos na área do petróleo, com o objetivo de propor um modelo inicial de simulador numérico de reservatórios. Inicialmente apresentamos uma EDP do calor não-linear com um termo fonte de calor constante, estudada para o domínio sendo uma placa plana quadrada homogênea e heterogênea, onde aplicamos soluções numéricas utilizando o método das diferenças finitas implícito. Abordamos o problema de refinamento da malha no entorno dos poços utilizando o método JFNK (Jacobian-Free Newton-Krylov), que aumenta a eficiência computacional através de uma aproximação para a matriz Jacobiana. Por fim resolvemos um sistema de EDPs não-lineares que representam o escoamento bifásico de água e óleo, constituído por equações de transporte em termos da pressão e da saturação. Fizemos simulações numéricas de alguns casos conhecidos e os resultados mostraram uma boa qualidade no nosso método. / [en] In this work we focus on the numerical approximation of some mathematical models in the oil field. First, we present a non-linear heat equation with a constant heat source term, studied for the domain of a homogeneous and heterogeneous square domain, where we apply numerical solutions using an implicit finite difference method. We approach the problem of mesh refinement around the wells using the JFNK (Jacobian- Free Newton-Krylov) method, which improves the computational efficiency through an approximation to the Jacobian matrix. Finally, we solve a system of non-linear EDPs that represent the two-phase flow of water and oil, consisting of equations of transport in terms of pressure and saturation. Numerical simulations for some known cases showed accurate approximation of our method.

No description available.

Au cours des vingt dernières années, l’anesthésie régionale est devenue, autant en médecine vétérinaire qu’humaine, un outil essentiel à l’élaboration de protocoles analgésiques péri-opératoires. Parmi l’éventail de techniques mises au point en anesthésie canine, le bloc paravertébral du plexus vertébral (PBPB) et sa version modifiée sont d’un grand intérêt pour toute procédure du membre thoracique, dans sa portion proximale. Toutefois, l’essentiel des données publiées à ce jour provient d’études colorimétriques, sans évaluation clinique, et peu d’information est disponible sur les techniques de localisation nerveuse envisageables à ce site. Notre étude visait à décrire une approche échoguidée du PBPB modifié, puis à caractériser ses paramètres pharmacocinétiques et pharmacodynamiques après administration de lidocaïne (LI) ou lidocaïne adrénalinée (LA). Huit chiens ont été inclus dans un protocole prospectif, randomisé, en aveugle et croisé, réparti sur trois périodes. L’impact pharmacodynamique du bloc effectué avec LI ou LA a été évalué régulièrement pour 180 min suivant son exécution. Le traitement à l’adrénaline n’a pas démontré d’impact significatif (P = 0,845) sur la durée du bloc sensitif, tel qu’évalué par un stimulus douloureux mécanique appliqué aux dermatomes ciblés. À l’opposé, l’atteinte proprioceptive évaluée par la démarche a été trouvée prolongée (P = 0,027) et le bloc moteur mesuré par le pic de force verticale (PVF) au trot sur la plaque de force s’est avéré plus marqué (PVF réduit; P = 0,007) sous LA. À l’arrêt comme au trot, le nadir de la courbe PVF-temps a été trouvé retardé (P < 0,005) et la pente ascendante de retour aux valeurs normales adoucie (P = 0,005). Parallèlement aux évaluations cliniques, des échantillons plasmatiques ont été collectés régulièrement afin de quantifier et décrire le devenir pharmacocinétique de la lidocaïne. Parmi les trois élaborés, un modèle bi-compartimental doté d’une double absorption asynchrone d’ordre zéro a finalement été sélectionné et appliqué aux données expérimentales. Sous LA, la Cmax a été trouvée significativement diminuée (P < 0,001), les phases d’absorption prolongées [P < 0,020 (Dur1) et P < 0,001 (Dur2)] et leurs constantes réduites [P = 0,046(k01) et P < 0,001 (k02)], le tout en concordance avec les effets proprioceptifs et moteurs rapportés. Bien que l’extrapolation du dosage soit maintenant théoriquement envisageable à partir du modèle mis en lumière ici, des études supplémentaires sont encore nécessaires afin d’établir un protocole de PBPB d’intérêt clinique. L’analyse sur plaque de force pourrait alors devenir un outil de choix pour évaluer l’efficacité du bloc dans un cadre expérimental. / Over the last decade, regional anaesthesia has become a gold standard for peri-surgical management in veterinary medicine. Among the many techniques developed for analgesia in dogs, the paravertebral brachial plexus block (PBPB) is of great interest when targeting the proximal half of the thoracic limb. Yet, most available data on this technique is based on colorimetric protocols rather than clinical evaluation, and there are very few published results for PBPB execution using nerve location techniques. Through this work, we wished to describe an ultrasound-guided approach of the PBPB and characterize its pharmacokinetic/ pharmacodynamic parameters when executed with either lidocaine alone (LI) or combined to adrenaline (LA). Eight dogs were included in a prospective, randomised, blinded, crossover protocol performed over three distinct periods. Pharmacodynamic impact of LI and LA was compared for 180 minutes after block administration. No significant difference (P = 0.845) was noted between treatments regarding length of the sensitive block, as evaluated regularly through a mechanical painful stimulus applied to selected dermatomes. On the opposite, gait examination showed a longer proprioceptive deficit using LA (P = 0.027). Motor block measured with dynamic force plate analysis showed a lower peak vertical force with LA than LI (P = 0.007). For both dynamic and static evaluations, nadir was clearly delayed (P < 0.005) and the ascending slope back to baseline significantly softened (P = 0.005) in the LA group. Throughout block execution and evaluation, blood samples were collected regularly in order to quantify and describe lidocaine kinetics. Models where developed and compared. A two-compartment model with dual zero-order absorption processes was selected as the best fit for our experimental data. Cmax proved to be significantly reduced with LA (P < 0.001), thus reducing potential toxicity. Absorption phase was prolonged [P < 0.020 (Dur1) and P < 0.001 (Dur2)] and zero-order absorption constant rates lowered [P = 0.046(k01) and P < 0.001 (k02)] following adrenaline addition, in accordance with the previously noted prolonged gait and motor effects. Though dosage extrapolation is now possible using the model developed and tested here, further studies would be needed to establish a PBPB protocol of more clinical interest. Then, force plate analysis could become a key tool for block quality assessment, as both dynamic and static measurements proved to be the reliable ways to collect ground reaction force (GRF) data.

This thesis describes the synthesis, characterisation and application of artificial metalloenzymes as catalysts. The focus was on two mutants of SCP-2L (SCP-2L A100C and SCP-2L V83C) both of which possess a hydrophobic tunnel in which apolar substrates can accumulate. The crystal structure of SCP-2L A100C was determined and discussed with a special emphasis on its hydrophobic tunnel. The SCP-2L mutants were covalently modified at their unique cysteine with two different N-ligands (phenanthroline or dipicolylamine based) or three different phosphine ligands (all based on triphenylphosphine) in order to increase their binding capabilities towards metals. The metal binding capabilities of these artificial proteins towards different transition metals was determined. Phenanthroline modified SCP-2L was found to be a promising scaffold for Pd(II)-, Cu(II)-, Ni(II)- and Co(II)-enzymes while dipicolylamine-modified SCP-2L was found to be a promising scaffold for Pd(II)-enzymes. The rhodium binding capacity of two additional phosphine modified protein scaffolds was also investigated. Promising scaffolds for Rh(I)- and Ir(I)-enzymes were identified. Rh-enzymes of the phosphine modified proteins were tested in the aqueous-organic biphasic hydroformylation of linear long chain 1-alkenes and compared to the Rh/TPPTS reference system. Some Rh-enzymes were found to be several orders of magnitude more active than the model system while yielding comparable selectivities. The reason for this remarkable reactivity increase could not be fully elucidated but several potential modes of action could be excluded. Cu-, Co-, and Ni-enzymes of N-ligand modified SCP-2L A100C were tested in the asymmetric Diels-Alder reaction between cyclopentadiene and trans-azachalcone. A promising 29% ee for the exo-product was found for the phenanthroline modified protein in the presence of nickel. Further improvement of these catalyst systems by chemical means (e.g. optimisation of ligand structure) and bio-molecular tools (e.g. optimisation of protein environment) can lead to even more active and (enantio)selective catalysts in the future.