Mixed micelles and gels of a hydrophilic poloxamine (Tetronic 1307) and miltefosine: Structural characterization by small-angle neutron scattering and in vitro evaluation for the treatment of leishmaniasis

Hypothesis/background: Tetronic is a family of four-armed amphiphilic block copolymers of polyethylene oxide (PEO) and polypropylene oxide (PPO) that self-aggregate to form micelles and hydrogels. Due to their temperature and pH-responsiveness, they are emerging as smart nanomaterials in the area of drug delivery. Here we propose the use of Tetronic 1307 (T1307) as a nanocarrier of miltefosine (MF), a zwitterionic alkylphospholipid highly active against leishmaniasis, one of the most threating neglected tropical diseases. Given the amphiphilic nature of the drug, both surfactants can combine to form mixed micelles, reducing the cytotoxicity of MF by lowering its dose and improving its internalization, hence its antileishmanial effect. Experiments: The structure of the T1307 micelles, MF micelles, mixed micelles and hydrogels, formed in buffered solution (pH = 7.4) at different concentrations has been investigated in-depth by a combination of small-angle neutron scattering (SANS), dynamic light scattering (DLS), fluorescence spectroscopy and nuclear magnetic resonance methods (1D, 2D NOESY, and diffusion NMR). The cytotoxicity of the aggregates in macrophages has been assessed, as well as the antileishmanial activity in both Leishmania major promastigotes and amastigotes. Findings: T1307 and MF combine into mixed aggregates over a wide range of temperatures and compositions, forming ellipsoidal core–shell mixed micelles. The shell is highly hydrated and comprises most of the PEO blocks, while the hydrophobic core contains the PO blocks and the MF along with a fraction of EO and water molecules, depending on the molar ratio in the mixture. The combination with T1307 amplified the leishmanicidal activity of the drug against both forms of the parasite and dramatically reduced drug cytotoxicity. T1307 micelles also showed a considerable leishmanicidal activity without exhibiting macrophage toxicity. These results support the use of T1307 as a MF carrier for the treatment of human and animal leishmaniasis, in its different clinical forms

As variações linguísticas no ensino de português no 9º ano do Colégio Estadual Profª Irany Nunes do Prado comunidade Prata Monte Alegre GO : um estudo de caso

Trabalho de conclusão de curso (graduação)—Universidade de Brasília, Faculdade UnB Planaltina, Licenciatura em Educação do Campo, 2017.A pesquisa trata sobre Sociolinguística e Educação: as variações linguísticas no ensino de português no 9º ano do Colégio Estadual Irany Nunes do Prado do Povoado Prata na cidade de Monte Alegre de Goiás. O trabalho está inserido na área de Linguística e do letramento, partindo dos socioletos dentro da variação social para identificar os níveis lexicais, semânticos e fonológicos existentes. A importância da pesquisa se dá pela necessidade de conhecimento e de referenciar a Sociolinguística, diante da abordagem feita por professores sobre o uso da língua em sala de aula. Os objetivos da pesquisa foram averiguar os fatores que contribuem para a propagação do preconceito linguístico dentro do espaço escolar, com possibilidades de enfrentamento deste preconceito na escola, identificando como é a fala dos alunos da instituição e a dos moradores do Povoado. Buscamos também identificar os fatores que contribuem para o processo de letramento seja pouco desenvolvido entre os estudantes, que de uma forma severa impulsiona-os a utilizar as variações linguísticas até mesmo em situações que envolvem a escrita, contrariando a maneira formal padrão. A metodologia utilizada pauta-se na pesquisa qualitativa, com análise descritiva da comunidade, do colégio onde a pesquisa foi realizada e das ocorrências vivenciadas, abordando de forma analítica os contextos que envolvem o colégio e a comunidade em geral. Foram seguidos procedimentos teóricos com pesquisa bibliográfica e etnográfica, por meio de observação participante, entrevistas e narrativas escritas. Os resultados apontam que a Sociolinguística tem se apresentado como fator relevante no cenário educativo brasileiro; que muitas vezes as variações linguísticas são deixadas de lado pelos professores no processo de letramento em sala de aula. Na comunidade, as pessoas separam o falar em “correto” e “incorreto”, ocasionando um problema no processo cultural, já que há variações, e falar de uma forma diferente não é necessariamente um erro. Os resultados apontam para uma realidade onde se torna necessário uma intervenção pedagógica com planejamento adequado, com aulas direcionadas ao uso das variações linguísticas praticadas pelos alunos da escola, no intuito de se aprimorar a linguagem utilizada de maneira formal e em função da valorização da linguagem usada de maneira informal na comunidade.The research deals with sociolinguistics and education: language variations in the teaching of Portuguese in the 9th grade of Public School Irany Prado Nunes of the Village Prata, in the city of Monte Alegre of Goiás The work is inserted in the Linguistics area and literacy, starting from socioletos within the social variation to identify lexical levels, existing semantic and phonological. The importance of research is given by the need of knowledge and reference Sociolinguistics, before the approach made by teachers about the use of language in the classroom. The research objectives were to ascertain the factors that contribute to the spread of linguistic discrimination within the school environment, with coping possibilities of this prejudice at school by identifying how the speech of students of the institution and the residents of the Village. We also seek to identify the factors that contribute to the literacy process is poorly developed among students, which in a severe form propels them to use the language variations even in situations that involve writing, contrary to standard formally. The methodology is guided in qualitative research, with descriptive analysis of the community, the school where the study was conducted and experienced events, addressing an analytical way the contexts surrounding the school and the community at large. Theoretical procedures were followed with bibliographic and ethnographic research through participant observation, interviews and written narratives. The results show that the Sociolinguistics has performed as a relevant factor in the Brazilian educational setting; that often linguistic variations are left out by teachers in the literacy process in the classroom. In the community, people separate speaking in "correct" and "incorrect", causing a problem in the cultural process, since there are variations, and speak in a different way is not necessarily an error. The results point to a reality where an educational intervention is necessary with proper planning, with classes directed to the use of linguistic variations practiced by school students in order to improve the language in a formal way and due to the appreciation of the language used informally in the community

Chemical modification of PDMS surface without impacting the viscoelasticity: Model systems for a better understanding of elastomer/elastomer adhesion and friction

The influence of both viscoelastic and interfacial parameters on the surface properties of elastomers is difficult to study. Here, we describe a simple route to achieve surface modification of PDMS without impacting the viscoelastic properties of the bulk. PEG modified PDMS surfaces were synthesized by two step surface modification based on hydrosilylation. The covalent grafting of PEG on the surface has been evidenced by AFM and ATR-FTIR, and its effect on the hydrophilicity characterized by static and dynamic contact angle. The static water contact angle of the PEG-modified PDMS decreases from 110° (for unmodified PDMS) to 65°. Dynamic contact angles also show a significant decrease in both advancing and receding contact angles, along with a significant increase in the contact angle hysteresis, which can be related to an increase in the surface energy as estimated by JKR measurements. The viscoelastic properties of modified PDMS are found to be quantitatively comparable to those of the unmodified PDMS. This simple method is an efficient way to prepare model materials which can be used to get a better understanding of the exact contribution of the surface chemistry on surface properties of elastomers

Using p-Si/BDD anode for the electrochemical oxidation of norfloxacin

[EN] This study evaluated the electrochemical advanced oxidation process (EAOP) using boron-doped diamond (p-Si/BDD) anode in the abatement of the antibiotic norfloxacin (NOR). The influence of the applied current density (iapp), initial concentration of NOR, sodium sulfate (Na2SO4) concentration and reactor operation conditions were evaluated. The mechanism of NOR oxidation (direct or indirect) was also studied by cyclic voltammetry and chronoamperometry. The results showed that, depending on the iapp, and the NOR and Na2SO4 concentration, the NOR could be oxidized by direct electron transfer, with the carbon-sp2 impurities on the p-Si/BDD surface, and indirect, by persulfate ions (S2O82¿), sulfate (SO4·¿) and/or hydroxyl radicals (HO) electro-generated at the anode surface. When the reactor is operated favoring the electro-generated HO, NOR abatement and chemical oxygen demand (COD) reduction are simultaneous. Conversely, at the time that the reactor is operated favoring the NOR direct oxidation and by S2O82¿ and SO4·¿, NOR and COD reduction are not parallel leading to high byproducts formation. Therefore, it is important to know the matrix content (organic and sulfate content), for the correct choice of the operational parameters that will lead to a low byproducts formation.The authors thank Cyted, CNPq, CAPES/DGPU project no. 7595/14-0, FAPERGS and FINEP. The authors thank the financial support from MINECO (Ministerio de Economia y Competitividad, Spain) under project CTQ2015-65202-C2-1-R, co-financed with FEDER funds.Wohlmuth Da Silva, S.; Ortega Navarro, EM.; Siqueira Rodrigues, MA.; Moura Bernardes, A.; Pérez-Herranz, V. (2019). Using p-Si/BDD anode for the electrochemical oxidation of norfloxacin. Journal of Electroanalytical Chemistry. 832:112-120. https://doi.org/10.1016/j.jelechem.2018.10.049S11212083

Studies on oxidation/mineralization kinetics and mechanism of antibiotics sulfamethoxazole (SMX), amoxicillin (AMX) and sulfachloropyridazine (SPC) in aqueous media by electrochemical advanced oxidation processes : measuring and monitoring the evolution of toxicity during treatment

Suite à leur utilisation, les médicaments sont souvent partiellement métabolisés; ainsi ces substances pharmaceutiques et/ou leurs métabolites sont rejetés continuellement dans les eaux usées. Leur présence et accumulation dans les eaux naturelles constituent une pollution émergente conduisant à la perturbation des écosystèmes et l'accroissement de mal fonctionnement de la reproduction des espèces aquatiques telles que les poissons. Parmi les polluants pharmaceutiques, les antibiotiques méritent une attention particulière parce qu'ils sont utilisés en grande quantité d'une part et constituent des molécules biologiquement actives pouvant interagir avec des cibles biologiques spécifiques conduisant à l'apparition du phénomène de résistance des micro-organismes potentiellement pathogènes tels que les bactéries (vis-à-vis de ces médicaments employés pour les combattre). Une action préventive est donc indispensable pour réduire leur présence dans les milieux aquatiques naturels.Dans ce travail nous avons appliqué le procédé électro-Fenton (EF), une méthode indirecte d'oxydation électrochimique très performante, à la dégradation des polluants pharmaceutiques sélectionnés, trois antibiotiques couramment utilisés : le sulfaméthoxazole (SMX), l'amoxicilline (AMX) et sulfachloropyridazine (SCP). Le traitement des solutions aqueuses de ces antibiotiques été réalisé en milieux aqueux acide à l'aide des radicaux hydroxyles générés électrochimiquement. Les radicaux hydroxyles sont produits in situ à courant constant dans une cellule électrochimique non divisée, munie d'une cathode tridimensionnelle de grande surface spécifique (feutre de carbone) et d'une anode de Pt ou de BDD afin de suivre la cinétique d'oxydation avec les radicaux hydroxyles et la minéralisation de leurs solutions aqueuses. Ces radicaux sont générés à travers la réaction de Fenton :H2O2 + Fe2+ + H+ → Fe3+ + H2O + •OHdans laquelle les réactifs générés (H2O2) ou régénéré (Fe2+ en tant que catalyseur) électrocatalytiquemment. L'influence des différents paramètres sur la cinétique de dégradation des antibiotiques et sur la cinétique de minéralisation des solutions d'antibiotiques a été étudiée. L'effet co-catalytique des ions Cu2+ a été aussi examiné. Les radicaux hydroxyles formés sont des oxydantes très puissants et réagissent sur les antibiotiques en question conduisant à leur minéralisation. L'étude cinétique montre que la dégradation oxydative des trois antibiotiques suit une cinétique de réaction du pseudo-premier ordre, avec des temps de dégradation assez courts. Par exemple, avec une anode de Pt, l'oxydation complète des molécules SMX, AMX et SCP a été achevée en moins de 15 min à 300 mA.Afin d'établir les voies de dégradation avec les radicaux hydroxyles, les intermédiaires aromatiques, les acides carboxyliques formés ainsi que les ions inorganiques libérés dans la solution lors du traitement ont été identifiés et leur évolution dans le temps a été suivie. Les valeurs des constantes de vitesse des réactions entre les •OH et les antibiotiques et leurs intermédiaires ont été déterminés par la technique de cinétique de compétition à l'aide d'un composé de référence, l'acide p-hydroxybenzoϊque. L'efficacité du procédé d'oxydation anodique (OA) avec une anode Pt et BDD à titre comparatif avec le procédé électro-Fenton a été aussi étudiée. L'efficacité de minéralisation des solutions aqueuses d'antibiotique à été évaluée par mesure du carbone organique total (COT). Le suivi de la toxicité lors du traitement des solutions d'antibiotiques par la méthode Microtox®, (une méthode basée sur la mesure de la luminescence des bactéries marines Vibrio fischeri) a montré la formation des intermédiaires plus toxiques que les molécules mères.L'ensemble des résultats obtenus confirme l'efficacité du procédé électro-Fenton pour la dépollution des effluents aqueux chargés d'antibiotiquesAfter their use, the drugs used in human or veterinary are partially metabolized during their use and then the non metabolized drugs and/or their metabolites are continuously released into the wastewater. Their presence and accumulation in natural waters of these substances constitutes an emerging pollution leading to the disruption of ecosystems and increased malfunction in the reproduction of aquatic species such as fish. Among the, pharmaceuticals pollutants, the antibiotics deserve special attention because they are used in very large quantities and are biologically active molecules that can interact with specific biological targets leading to emergence of the phenomenon of microorganism's resistance towards the potential pathogens such as bacteria. It is therefore important to develop efficient treatment methodologies for limiting the presence of pharmaceutical contaminants in aquatic environments.In this work we applied the electro-Fenton process (EF), an indirect advanced electrochemical oxidation process, to the oxidative degradation of selected three antibiotics largely used: sulfamethoxazole (SMX), amoxicillin (AMX) and sulfachloropyridazine (SCP). The treatment of aqueous solutions of these antibiotics was achieved in aqueous medium thank to the electrochemically generated hydroxyl radicals. The hydroxyl radicals are produced in situ at constant current in an undivided electrochemical cell, equipped with a three-dimensional cathode (carbon felt) and a Pt or BDD anode. These radicals are generated through the Fenton reaction in homogeneous medium:H2O2 + Fe2+ + H+ → Fe3+ + H2O + •OHwith the electrochemical generation of H2O2 (from 2-electrons reduction of dissolved O2) and regeneration of Fe2+ ions (from one-electron reduction of Fe3+ ions formed by Fenton reaction).The effect of some parameters on the oxidative degradation of antibiotics and on the mineralization of their aqueous solutions was investigated. The co-catalytic effect of Cu2+ was also studied. Hydroxyl radicals formed in aqueous medium are very powerful oxidizing agents and lead to mineralization of antibiotic under study. The kinetics study shows that oxidative degradation of the three antibiotics follows a pseudo-first order, with relatively short degradation time. For example, with a Pt anode, the complete oxidation of antibiotics SMX, AMX and SCP was achieved in less than 15 min at 300 mA. The absolute rate constant of hydroxylation reactions of antibiotics under study and their several aromatic intermediates was determined by competition kinetics method using the p-hydroxybenzoic acid as reference compound. The identification and monitoring of aromatic oxidation products, short-chain carboxylic acids and released inorganic ions during the treatment, allow use to propose a general mineralization reaction pathway for antibiotics degradation by hydroxyl radicals. The efficiency of anodic oxidation (AO) with a BDD anode and Pt was also studied comparatively. The efficiency of mineralization of aqueous solutions of antibiotics was evaluated by measuring total organic carbon (TOC). The evolution of toxicity during the treatment of antibiotic solutions by Microtox® method based on the inhibition measurements of the luminescence of marine bacteria Vibrio fischeri showed the formation of intermediates more toxic than of starting molecules. The overall results confirm the efficiency of electro-Fenton method for remediation of wastewater contaminated with antibiotic

Études cinétique et mécanistique d'oxydation/minéralisation des antibiotiques sulfaméthoxazole (SMX), amoxicilline (AMX) et sulfachloropyridazine (SPC) en milieux aqueux par procédés électrochimiques d'oxydation avancée : mesure et suivi d'évolution de la toxicité lors du traitement

After their use, the drugs used in human or veterinary are partially metabolized during their use and then the non metabolized drugs and/or their metabolites are continuously released into the wastewater. Their presence and accumulation in natural waters of these substances constitutes an emerging pollution leading to the disruption of ecosystems and increased malfunction in the reproduction of aquatic species such as fish. Among the, pharmaceuticals pollutants, the antibiotics deserve special attention because they are used in very large quantities and are biologically active molecules that can interact with specific biological targets leading to emergence of the phenomenon of microorganism's resistance towards the potential pathogens such as bacteria. It is therefore important to develop efficient treatment methodologies for limiting the presence of pharmaceutical contaminants in aquatic environments.In this work we applied the electro-Fenton process (EF), an indirect advanced electrochemical oxidation process, to the oxidative degradation of selected three antibiotics largely used: sulfamethoxazole (SMX), amoxicillin (AMX) and sulfachloropyridazine (SCP). The treatment of aqueous solutions of these antibiotics was achieved in aqueous medium thank to the electrochemically generated hydroxyl radicals. The hydroxyl radicals are produced in situ at constant current in an undivided electrochemical cell, equipped with a three-dimensional cathode (carbon felt) and a Pt or BDD anode. These radicals are generated through the Fenton reaction in homogeneous medium:H2O2 + Fe2+ + H+ → Fe3+ + H2O + •OHwith the electrochemical generation of H2O2 (from 2-electrons reduction of dissolved O2) and regeneration of Fe2+ ions (from one-electron reduction of Fe3+ ions formed by Fenton reaction).The effect of some parameters on the oxidative degradation of antibiotics and on the mineralization of their aqueous solutions was investigated. The co-catalytic effect of Cu2+ was also studied. Hydroxyl radicals formed in aqueous medium are very powerful oxidizing agents and lead to mineralization of antibiotic under study. The kinetics study shows that oxidative degradation of the three antibiotics follows a pseudo-first order, with relatively short degradation time. For example, with a Pt anode, the complete oxidation of antibiotics SMX, AMX and SCP was achieved in less than 15 min at 300 mA. The absolute rate constant of hydroxylation reactions of antibiotics under study and their several aromatic intermediates was determined by competition kinetics method using the p-hydroxybenzoic acid as reference compound. The identification and monitoring of aromatic oxidation products, short-chain carboxylic acids and released inorganic ions during the treatment, allow use to propose a general mineralization reaction pathway for antibiotics degradation by hydroxyl radicals. The efficiency of anodic oxidation (AO) with a BDD anode and Pt was also studied comparatively. The efficiency of mineralization of aqueous solutions of antibiotics was evaluated by measuring total organic carbon (TOC). The evolution of toxicity during the treatment of antibiotic solutions by Microtox® method based on the inhibition measurements of the luminescence of marine bacteria Vibrio fischeri showed the formation of intermediates more toxic than of starting molecules. The overall results confirm the efficiency of electro-Fenton method for remediation of wastewater contaminated with antibioticsSuite à leur utilisation, les médicaments sont souvent partiellement métabolisés; ainsi ces substances pharmaceutiques et/ou leurs métabolites sont rejetés continuellement dans les eaux usées. Leur présence et accumulation dans les eaux naturelles constituent une pollution émergente conduisant à la perturbation des écosystèmes et l'accroissement de mal fonctionnement de la reproduction des espèces aquatiques telles que les poissons. Parmi les polluants pharmaceutiques, les antibiotiques méritent une attention particulière parce qu'ils sont utilisés en grande quantité d'une part et constituent des molécules biologiquement actives pouvant interagir avec des cibles biologiques spécifiques conduisant à l'apparition du phénomène de résistance des micro-organismes potentiellement pathogènes tels que les bactéries (vis-à-vis de ces médicaments employés pour les combattre). Une action préventive est donc indispensable pour réduire leur présence dans les milieux aquatiques naturels.Dans ce travail nous avons appliqué le procédé électro-Fenton (EF), une méthode indirecte d'oxydation électrochimique très performante, à la dégradation des polluants pharmaceutiques sélectionnés, trois antibiotiques couramment utilisés : le sulfaméthoxazole (SMX), l'amoxicilline (AMX) et sulfachloropyridazine (SCP). Le traitement des solutions aqueuses de ces antibiotiques été réalisé en milieux aqueux acide à l'aide des radicaux hydroxyles générés électrochimiquement. Les radicaux hydroxyles sont produits in situ à courant constant dans une cellule électrochimique non divisée, munie d'une cathode tridimensionnelle de grande surface spécifique (feutre de carbone) et d'une anode de Pt ou de BDD afin de suivre la cinétique d'oxydation avec les radicaux hydroxyles et la minéralisation de leurs solutions aqueuses. Ces radicaux sont générés à travers la réaction de Fenton :H2O2 + Fe2+ + H+ → Fe3+ + H2O + •OHdans laquelle les réactifs générés (H2O2) ou régénéré (Fe2+ en tant que catalyseur) électrocatalytiquemment. L'influence des différents paramètres sur la cinétique de dégradation des antibiotiques et sur la cinétique de minéralisation des solutions d'antibiotiques a été étudiée. L'effet co-catalytique des ions Cu2+ a été aussi examiné. Les radicaux hydroxyles formés sont des oxydantes très puissants et réagissent sur les antibiotiques en question conduisant à leur minéralisation. L'étude cinétique montre que la dégradation oxydative des trois antibiotiques suit une cinétique de réaction du pseudo-premier ordre, avec des temps de dégradation assez courts. Par exemple, avec une anode de Pt, l'oxydation complète des molécules SMX, AMX et SCP a été achevée en moins de 15 min à 300 mA.Afin d'établir les voies de dégradation avec les radicaux hydroxyles, les intermédiaires aromatiques, les acides carboxyliques formés ainsi que les ions inorganiques libérés dans la solution lors du traitement ont été identifiés et leur évolution dans le temps a été suivie. Les valeurs des constantes de vitesse des réactions entre les •OH et les antibiotiques et leurs intermédiaires ont été déterminés par la technique de cinétique de compétition à l'aide d'un composé de référence, l'acide p-hydroxybenzoϊque. L'efficacité du procédé d'oxydation anodique (OA) avec une anode Pt et BDD à titre comparatif avec le procédé électro-Fenton a été aussi étudiée. L'efficacité de minéralisation des solutions aqueuses d'antibiotique à été évaluée par mesure du carbone organique total (COT). Le suivi de la toxicité lors du traitement des solutions d'antibiotiques par la méthode Microtox®, (une méthode basée sur la mesure de la luminescence des bactéries marines Vibrio fischeri) a montré la formation des intermédiaires plus toxiques que les molécules mères.L'ensemble des résultats obtenus confirme l'efficacité du procédé électro-Fenton pour la dépollution des effluents aqueux chargés d'antibiotique

Elaboration de matériaux micro-nanostructurés à morphologies contrôlées, à base de tungstates, pour la photo-dégradation

In the framework of the development of new technologies for environmental protection, andmore specially for the depollution of water or air, this work deals with the implementation ofsemiconductor materials with controlled morphologies, likely photocatalytic activities andtheir enabling the degradation or transformation of organic molecules in aqueous media.Several types of syntheses leading to diversified morphologies have been implemented. Eachmaterial was characterized by X-ray diffraction, scanning and transmission electronmicroscopies, and Raman spectroscopy. Diffuse reflectance was used to determine the bandgap of the materials. Given the properties already known for MWO4 tungstates, we chosethree materials: WO3 trioxide, SrWO4 tungstate and a new tungstate NaCe(WO4)2 orNa0.5Ce0.5WO4. The oxide WO3 was chosen as the reference material. For this material, twotypes of morphologies were obtained: nanoplates and nanospheres. The tungstate SrWO4 withscheelite structure was synthesized in two microstructural forms: spindles and spheres. A newmaterial was synthesized and characterized: double tungstate of Na0.5Ce0.5WO4 with scheelitestructure. For this new phase, three hierarchical 3D morphologies were developed using thehydrothermal method in the presence of EDTA. For each observed morphology, agermination-growth mechanism is proposed. The photocatalytic performances of the differentmorphological forms were evaluated during the degradation of rhodamine B (RhB) andmethylene blue (MB), under UV and visible radiation. The photocatalytic efficiency of thedifferent microstructures was studied as a function of the pH of the reaction medium. Fromthe results obtained, we have been able to show the strong correlation between band gap andphotocatalytic reactivity, but also between morphologies, sizes and photocatalytic properties.It has been shown that the degradation is based on two complementary mechanisms: theadsorption of molecules due to the porosity of the microstructures and their morphology, andthe photocatalytic reaction due to the active radicals generated by the photogenerated e-/ h+pairs. Thus, RhB decomposes in the presence of SrWO4 and WO3 under UV-C (254 nm) andUV-Vis (365 nm) respectively. Methylene blue degrades in the presence of NaCe(WO4)2under UV-Vis solar radiation.Dans le cadre du développement de nouvelles technologies pour la protection environnementale, et tout particulièrement pour la dépollution de l’eau ou de l’air, le présent travail de thèse porte sur la mise en œuvre de matériaux semiconducteurs à morphologies contrôlées, susceptibles d’activités photocatalytiques permettant la dégradation ou la transformation de molécules en milieux aqueux. Plusieurs types de synthèses conduisant à des morphologies diversifiées ont été mises en œuvre. Chaque matériau a été caractérisé par diffraction de rayons X, microscopies électroniques à balayage et en transmission, et parspectroscopie Raman. La réflectance diffuse a été utilisée pour déterminer les énergies de bandes interdites des matériaux. Compte tenu des propriétés déjà connues pour les tungstates de type MWO4, notre choix s’est orienté vers trois matériaux : le trioxyde WO3, le tungstate SrWO4 et un nouveau tungstate NaCe(WO4)2 ou Na0,5Ce0,5WO4. L’oxyde WO3 a été choisi comme matériau de référence. Pour ce matériau, deux types de morphologies ont été obtenues : des nanoplaquettes et des nanosphères. Le tungstate SrWO4 de structure scheelite a été synthétisé sous deux formes microstructurales : des sphères et des navettes. Un nouveau matériau a été synthétisé et caractérisé : le tungstate double Na0,5Ce0,5WO4 de structure scheelite. Pour cette nouvelle phase, trois morphologies 3D hiérarchisées ont été élaborées en utilisant la méthode hydrothermale en présence d’EDTA. Pour chaque morphologie observée, un mécanisme de germination-croissance est proposé. Les performances photocatalytiques des différentes formes morphologiques ont été évaluées lors de la dégradation de la rhodamine B (RhB) et du bleu de méthylène (BM), sous rayonnements UV et visible. L’efficacité photocatalytique des différentes microstructures a été étudiée en fonction du pH du milieu réactionnel. À partir des résultats obtenus, nous avons pu montrer la forte corrélation entre largeur de bande interdite et réactivité photocatalytique, mais aussi entre morphologies, tailles et propriétés photocatalytiques. Il est apparu que la dégradation reposesur deux mécanismes complémentaires : l’adsorption des molécules due à la porosité des microstructures et à leur morphologie, et la réaction photocatalytique due aux radicaux actifs générés par les paires e-/h+ photogénérées. Ainsi, la RhB se décompose en présence de SrWO4 et WO3 sous UV-C (254 nm) et UV-Vis (365 nm) respectivement. Le bleu de méthylène se dégrade en présence de NaCe(WO4)2 sous rayonnement solaire UV-Vis

Development of micro-nanostructured materials, with controlled morphologies, based on tungstates for photo-degradation

Dans le cadre du développement de nouvelles technologies pour la protection environnementale, et tout particulièrement pour la dépollution de l’eau ou de l’air, le présent travail de thèse porte sur la mise en œuvre de matériaux semiconducteurs à morphologies contrôlées, susceptibles d’activités photocatalytiques permettant la dégradation ou la transformation de molécules en milieux aqueux. Plusieurs types de synthèses conduisant à des morphologies diversifiées ont été mises en œuvre. Chaque matériau a été caractérisé par diffraction de rayons X, microscopies électroniques à balayage et en transmission, et parspectroscopie Raman. La réflectance diffuse a été utilisée pour déterminer les énergies de bandes interdites des matériaux. Compte tenu des propriétés déjà connues pour les tungstates de type MWO4, notre choix s’est orienté vers trois matériaux : le trioxyde WO3, le tungstate SrWO4 et un nouveau tungstate NaCe(WO4)2 ou Na0,5Ce0,5WO4. L’oxyde WO3 a été choisi comme matériau de référence. Pour ce matériau, deux types de morphologies ont été obtenues : des nanoplaquettes et des nanosphères. Le tungstate SrWO4 de structure scheelite a été synthétisé sous deux formes microstructurales : des sphères et des navettes. Un nouveau matériau a été synthétisé et caractérisé : le tungstate double Na0,5Ce0,5WO4 de structure scheelite. Pour cette nouvelle phase, trois morphologies 3D hiérarchisées ont été élaborées en utilisant la méthode hydrothermale en présence d’EDTA. Pour chaque morphologie observée, un mécanisme de germination-croissance est proposé. Les performances photocatalytiques des différentes formes morphologiques ont été évaluées lors de la dégradation de la rhodamine B (RhB) et du bleu de méthylène (BM), sous rayonnements UV et visible. L’efficacité photocatalytique des différentes microstructures a été étudiée en fonction du pH du milieu réactionnel. À partir des résultats obtenus, nous avons pu montrer la forte corrélation entre largeur de bande interdite et réactivité photocatalytique, mais aussi entre morphologies, tailles et propriétés photocatalytiques. Il est apparu que la dégradation reposesur deux mécanismes complémentaires : l’adsorption des molécules due à la porosité des microstructures et à leur morphologie, et la réaction photocatalytique due aux radicaux actifs générés par les paires e-/h+ photogénérées. Ainsi, la RhB se décompose en présence de SrWO4 et WO3 sous UV-C (254 nm) et UV-Vis (365 nm) respectivement. Le bleu de méthylène se dégrade en présence de NaCe(WO4)2 sous rayonnement solaire UV-Vis.In the framework of the development of new technologies for environmental protection, andmore specially for the depollution of water or air, this work deals with the implementation ofsemiconductor materials with controlled morphologies, likely photocatalytic activities andtheir enabling the degradation or transformation of organic molecules in aqueous media.Several types of syntheses leading to diversified morphologies have been implemented. Eachmaterial was characterized by X-ray diffraction, scanning and transmission electronmicroscopies, and Raman spectroscopy. Diffuse reflectance was used to determine the bandgap of the materials. Given the properties already known for MWO4 tungstates, we chosethree materials: WO3 trioxide, SrWO4 tungstate and a new tungstate NaCe(WO4)2 orNa0.5Ce0.5WO4. The oxide WO3 was chosen as the reference material. For this material, twotypes of morphologies were obtained: nanoplates and nanospheres. The tungstate SrWO4 withscheelite structure was synthesized in two microstructural forms: spindles and spheres. A newmaterial was synthesized and characterized: double tungstate of Na0.5Ce0.5WO4 with scheelitestructure. For this new phase, three hierarchical 3D morphologies were developed using thehydrothermal method in the presence of EDTA. For each observed morphology, agermination-growth mechanism is proposed. The photocatalytic performances of the differentmorphological forms were evaluated during the degradation of rhodamine B (RhB) andmethylene blue (MB), under UV and visible radiation. The photocatalytic efficiency of thedifferent microstructures was studied as a function of the pH of the reaction medium. Fromthe results obtained, we have been able to show the strong correlation between band gap andphotocatalytic reactivity, but also between morphologies, sizes and photocatalytic properties.It has been shown that the degradation is based on two complementary mechanisms: theadsorption of molecules due to the porosity of the microstructures and their morphology, andthe photocatalytic reaction due to the active radicals generated by the photogenerated e-/ h+pairs. Thus, RhB decomposes in the presence of SrWO4 and WO3 under UV-C (254 nm) andUV-Vis (365 nm) respectively. Methylene blue degrades in the presence of NaCe(WO4)2under UV-Vis solar radiation

Predicting Drugs that Inhibit Growth in Cancerous Immortal Cell Lines

In this work, we explore the possibilities of predicting cancers using only information from compounds, and their target growth inhibition value for each cell line. We focused on representing the compounds in different ways such as with fingerprints and skeletal formulas. These representations were then fed into various neural nets and tree-based models to try to predict the growth inhibition values. We observed that tree-based methods on fingerprints performed the best over the various combinations of models and representations, and this performance rivals that of other previous works that combine a multitude of information about cell state and expression with compound data. These results indicate that compound information alone can be used to predict drugs that inhibit the growth of cancer, although more specialized models can push the predictive power even higher. With such specialized models, this form of prediction could be used even more to guide rational drug discovery in the fight against cancer