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Concept

Potentiel d'oxydoréduction

Le potentiel d'oxydoréduction, ou potentiel redox, est une grandeur empirique exprimée en volts et généralement notée E_{h} (ou, pour le potentiel redox standard, E(M/M) où M désigne un métal quelconque). Ce potentiel est exprimé par rapport à une référence, souvent mesurée par une électrode normale à hydrogène (ENH, d'où l'unité V/ENH rencontrée dans certains ouvrages). Cette mesure est appliquée aux couples d'oxydoréduction pour prévoir la réactivité des espèces chimiques entre elles. Le potentiel standard E est mesuré par rapport au couple proton/dihydrogène (H+/), de potentiel standard nul par convention. Mesure La mesure d'un potentiel d'oxydoréduction se fait expérimentalement à l'aide de deux demi-piles. Pour obtenir le potentiel standard d'un couple redox, l'une de ces piles doit mettre en œuvre le couple de référence H+/, et l'autre celui dont on veut mesurer le potentiel. Concrètement, les deux demi-piles sont constituées chacune d'un soluté et d'un

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This course covers the metallurgy, processing and properties of modern high-performance metals and alloys (e.g. advanced steels, Ni-base, Ti-base, High Entropy Alloys etc.). In addition, the principles of computational alloy design as well as approaches for a sustainable metallurgy will be addressed

Le cours "Microbiologie pour l'ingénieur" couvre les processus microbiens principaux qui ont lieu dans l'environnement et dans des systèmes de traitement. Il présente les cycles des éléments qui sont catalysés par des microorganismes et qui ont un impact important sur la planète Terre.

The aim of this course is to acquire the basic knowledge on specific dynamical phenomena related to the origin, equilibrium, and evolution of star clusters, galaxies, and galaxy clusters.

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The aim of this course is to acquire the basic knowledge on specific dynamical phenomena related to the origin, equilibrium, and evolution of star clusters, galaxies, and galaxy clusters.

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Réaction d'oxydoréduction

vignette|L'aluminothermie est une réaction d'oxydoréduction entre l'aluminium et certains oxydes métalliques. Une réaction d'oxydoréduction ou réaction rédox est une réaction chimique au cours de laqu

Équation de Nernst

En électrochimie, l'équation de Nernst donne la tension d'équilibre (E) de l'électrode par rapport au potentiel standard (E) du couple redox mis en jeu. Elle n'a de sens que si un seul couple redox es

Fer

Le fer est l'élément chimique de numéro atomique 26, de symbole Fe. Le corps simple est le métal et le matériau ferromagnétique le plus courant dans la vie quotidienne, le plus souvent sous forme d

Benign synthesis of quinolinecarboxamide ligands, H(2)bqbenzo and H(2)bqb and their Pd(II) complexes: X-ray crystal structure, electrochemical and antibacterial studies

Maryam Bagheri, Farzaneh Fadaei Tirani

Two carboxamide ligands, H(2)bqbenzo {3,4-bis(2-quinolinecarboxamido)benzophenone} and H(2)bqb {N,N-bis[(2-quinolinecarboxamide)-1,2-benzene]}, have been prepared using tetrabutylammonium bromide as an environmentally benign reaction medium. Two new Pd(II) complexes, [Pd-II(bqbenzo)] (1) and [Pd-II(bqb)] (2), have been synthesized, characterized, and their structures determined by single crystal X-ray diffraction. The di-anionic ligands, bqbenzo(2-) and bqb(2-), are coordinated via two N-amide atoms and the nitrogens of the two quinoline rings, with Pd-N-amide

Taylor & Francis Ltd2017

Chargement

Peptide-Polymer Conjugates for Therapeutic Applications

Ana Maria Raduta

Over the last ten years the attention of the pharmaceutical industry has shifted away from small molecules to focus on new biologics such as antibodies, proteins and therapeutic peptides. Herein, peptides have emerged as a particularly interesting category that fills a niche between small molecule chemicals and the larger proteins. Although they have great potential for drug development, their use is still limited due to their intrinsic low systemic stability, rapid renal elimination and poor membrane permeability. Various formulations have been developed to take advantage of their therapeutic properties, one of the most promising strategies being chemical conjugation to a polymer. Peptide-polymer conjugates are hybrid materials that consist of one or more synthetic polymers covalently attached to one or more peptide fragments. The aim of this thesis was to provide an insight into the requirements for the design of peptide-polymer conjugates for therapy. Chapter 1 illustrates the state of the art in the development of peptides for therapeutic applications, exemplifies the different architectures and structures of peptide-polymer conjugates and discusses ongoing efforts to improve and diversify the range and applications of these conjugates. Chapter 2 describes a novel synthetic strategy to prepare PHPMA based peptide-polymer conjugates via thiol chemistry starting from poly(pentafluorophenyl methacrylate). By varying the feed composition, the extent of side chain modification could be controlled. Further modification of the reactive copolymer scaffolds led to the site specific attachment of model peptides. This method was used to synthesize stable as well as pH and redox sensitive peptide-polymer conjugates and the release of the peptide from the polymer backbone was studied in acidic and redox conditions. In Chapter 3, the aim was to construct a peptide-polymer conjugate that could serve to promote intracellular delivery and drug release but also play a role in the intracellular trafficking of the drug. To this end, coiled coil peptides E3/K3 was attached to a PHPMA polymer backbone and was used to facilitate release from the backbone at acidic pH and further endosomal escape. Initially, the membrane lytic properties of E3/K3 and three newly designed E3/K3X motifs on model membranes were investigated as a function of pH. Secondly, the potential application of E3/K3 peptide-polymer conjugate for cytoplasmic delivery was evaluated in vitro. Chapter 4 explores the synthesis and in vitro therapeutic activity of synthetic peptide-polymer conjugates focusing on the inhibition of an oncogenic transcription factor (AP-1). To this end, AFosW peptide, a peptide binder that can interfere with AP-1 formation was attached to a polymer backbone via a redox or pH sensitive linker using a strategy developed in Chapter 2. Fluorescent microscopy and flow cytometry provided an insight into the cellular uptake of these conjugates. Their ability to interfere with AP-1 formation in vitro was quantified. Chapter 5 describes the synthesis of a second generation of peptide-polymer conjugates for AP-1 inhibition that along the FosW dominant negative peptide also incorporates a motif that facilitates endosomal escape and a nuclear localization sequence. To investigate the potential application for therapy, the conjugates were evaluated and compared with regard to their ability to inhibit AP-1 formation in living cells.

EPFL2015

Chargement

Sulfide oxidation and acid mine drainage formation within two active tailings impoundments in the Golden Quadrangle of the Apuseni Mountains, Romania

Linda Frei

Sulfidic mine tailings have to be classified as one of the major source of hazardous materials leading to water contamination. This study highlights the processes leading to sulfide oxidation and acid mine drainage (AMD) formation in the active stage of two tailings impoundments located in the southern part of the Apuseni Mountains, in Romania, a well-known region for its long-term gold-silver and metal mining activity. Sampling was undertaken when both impoundments were still in operation in order to assess their actual stage of oxidation and long-term behavior in terms of the potential for acid mine drainage generation. Both tailings have high potential for AMD formation (2.5 and 3.7 wt.% of pyrite equivalent, respectively) with lesser amount of carbonates (5.6 and 3.6 wt.% of calcite equivalent) as neutralization potential (ABA = -55.6 and -85.1 tCaCO(3)/1000 t) and showed clear signs of sulfide oxidation yet during operation. Sequential extraction results indicate a stronger enrichment and mobility of elements in the oxidized tailings: Fe as Fe(III)oxy-hydroxides and oxides (transformation from sulfide minerals, leaching in oxidation zone), Ca mainly in water soluble and exchangeable form where gypsum and calcite are dissolved and higher mobility of Cu for Ribita and Pb for Mialu. Two processes leading to the formation of mine drainage at this stage could be highlighted (1) a neutral Fe(II) plume forming in the impoundment with ferrihydrite precipitation at its outcrop and (2) acid mine drainage seeping in the unsaturated zone of the active dam, leading to the formation of schwertmannite at its outcrop. (C) 2011 Elsevier B.V. All rights reserved.

2011

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