La réhabilitation des sols pollués par les Hydrocarbures Aromatiques Polycycliques (HAP) est une problématique importante au niveau européen. Afin de développer une technique de bioremédiation, une collection de 30 souches de champignons saprotrophes est constitués à partir d'échantillons de sols historiquement pollués par les HAP provenant du Nord de la France. Ces souches sont caractérisées pour leur capacités de désorption et de dégradation du Benzo[a]pyrène (BaP) en milieu minéral. Quatre souches présentent des taux de dégradation du BaP supérieur à 30% après seulement 9 jours d'incubation en milieu minéral. Des mesures d'activités enzymatiques sur un panel de 14 souches permettent d'observer des concordances intéressantes entre les capacités de dégradation du BaP et des activités enzymatiques extracellulaires ou liées au cytochrome P450. Des essais au laboratoire de bioaugmentation/biostimulation en microcosmes de sols historiquement contaminés en HAP permettent une augmentation d'environ 25% de la dégradation des HAP totaux par rapport aux témoins après inoculation d'une souche de Talaromyceshelicus dans deux sols d'origines et de textures différentes. Le processus d'incorporation du BaP, un HAP à 5 cycles aromatiques, est étudié en microscopie chez une souche de Fusariumsolani. D'après nos résultats, cette molécule serait incorporée dans les cellules fongiques par un processus actif et dépendant du réseau d'actine du cytosquelette. Ce travail de thèse ouvre ainsi de nouvelles perspectives pour la compréhension des mécanismes de dégradation des HAP par les champignons saprotrophes telluriques et le développement de nouveaux protocoles de bioremédiation fongique des sols. / Recovery of soils polluted by Polycyclic Aromatic Hydrocarbons (PAH) is an important problematic at the European scale. In order to develop a bioremediation technique, a collection of 30 saprotrophic fungal strains is constituted using PAH historically contamined soil samples coming from the north of France. These strains are characterized for their capacity of Benzo[a]pyrene (BaP) desorption and degration in mineral medium. Four strains exhibit BaP degradation rates over 30% after 9 days of incubation in mineral medium. Measurements of enzymatic activities within a panel of 14 strains enable to observe interesting correlations between BaP degradation capacities and extracellular or cytochrome P450-linked enzymatic activities. Lab-scale bioaugmentation/biostimulation experiments in microcosms of PAH historically contamined soils enbale to observe an increase of approximately 25% of the total-PAH degradation compared to the blanks after the inoculation of a strain of Talaromyceshelicus in two soils differing by their origins and textures. The incorporation of BaP, a 5 aromatic rings PAH, is studied through microcopy in the strain Fusariumsolani. According to our results, this molecule would be incorporated in fungal cells through an active mechanism depending on the actin network of the cytoskeleton. This PhD thesis draws new perpectives for the understanding of PAH degradations mechanisms in telluric saprotrophic fungi and for the development of new fungal bioremediation protocols in soils.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Polycyclic aromatic hydrocarbons (PAHs) are a class of compounds characterized by having two or more condensed aromatic rings. These substances, as well as their nitrated and oxygenated derivatives, can be found widely spread as constituents of complex mixtures in the environment. A variety of PHAs, in many cases showing similar structures, can be found in the environment. The United States Environmental Protection Agency (U.S. EPA) has listed 16 PAHs based on their toxicological profiles, as priority pollutants. In the present study, the performance of the solid substrates Amberlite XAD-2, polyethylene, high-density polyurethane foam, silica gel and quartz fiber were investigated as alternative to XAD-2 to remove HPAs from solutions. The investigation of the adsorption of naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene and chrysene was conducted in aqueous solutions by batch experiments, considering the initial concentrations of substrates and PHAs, time, temperature and influence of cosolvency. Spectrophotometry and liquid chromatography with UV detection were used to assess the removal yield. The results showed that the yields of PAH strongly dependent on the substrate as well as the PHA. The PAHs were most quickly and almost totally (except chrysene and anthracene) removed by polyurethane foam. High density polyethylene behaves similarly to XAD-2. Among the investigated PHAs, chrysene showed a different behavior, since the best adsorbents for this compound were as silica gel and quartz fiber. Thus the personal samplers for PHAs must be prepared as a mix of adsorbents instead of having a unique composition. / Hidrocarbonetos policíclicos aromáticos (HPAs) fazem parte de uma classe de compostos caracterizados por terem dois ou mais anéis aromáticos condensados. Estas substâncias, assim como seus derivados nitrados e oxigenados, podem ser encontradas difundidas como componentes de misturas complexas no ambiente. Uma variedade de HPAs, que em muitos casos, mostram estruturas semelhantes, pode ser encontrada no meio ambiente. A Agência de Proteção Ambiental dos Estados Unidos (U.S EPA) listou 16 HPAs com base em seus perfis toxicológicos, como poluentes prioritários. No presente estudo, o desempenho do substrato de Amberlite XAD-2, polietileno de alta densidade, espuma de poliuretano, sílica gel e fibra de quartzo foram investigados como alternativa ao XAD-2 para remover HPAs a partir de soluções. O estudo da adsorção do naftaleno, acenaftileno, acenafteno, fluoreno, fenantreno, antraceno e criseno foi realizado em soluções aquosas através de experimentos em batelada, avaliando a influência das concentrações iniciais dos HPAs e substratos, tempo, temperatura e efeito do co-solvente. Espectrofotometria e cromatografia líquida com detecção por UV foram utilizados para avaliar o rendimento de remoção. Os resultados mostraram que os rendimentos são fortemente dependentes do substrato, bem como dos HPAs. Os HPAs foram mais rapidamente e quase totalmente removidos por espuma de poliuretano (exceto criseno e antraceno). O polietileno de alta densidade apresenta um comportamento semelhante ao de XAD-2. Entre os HPAs investigados, criseno apresentou um comportamento diferente, uma vez que os melhores adsorventes para este composto foram à sílica gel e a fibra de quartzo. Assim, os amostradores pessoais para HPAs devem ser preparados como uma mistura de adsorventes em vez de ter uma composição única.

Contorted polycyclic aromatic hydrocarbons have found increasing utility in the application of molecular electronics due to the surpamolecular properties that result from these non-planar structures. The [n]circulene series of molecules are particularly attractive members of the contorted aromatic family due to the unique structural implications that result from their changing value of n. For example, when n ≤ 5, the structures adopt a bowl-like shape; when n = 6, a planar structure is observed; and when 7 ≤ n ≤ 16, the compounds assume a saddle-like shape. Very few molecules exhibit the structural contortions that these contorted aromatics do – primarily because aromatic molecules desire to adopt highly planar conformations. Following the model of aromaticity developed by Erich Clar, we set our sights on the synthesis of tetrabenzo[8]circulene, the stabilized form of [8]circulene established through the addition of four fused benzenoid rings around the periphery of the molecule. The initial approach towards this structure employs a Diels-Alder [4 + 2] cycloaddition reaction and a palladium catalyzed arylation reaction as the key transformation steps. The results of these studies were promising, establishing the structural characterization of this new molecule and providing access to functionalized derivatives of the saddle-shaped structure. However, access towards these functionalized derivatives proved limiting, compelling us to investigate alternative synthetic methodologies. In the course of our studies, we established a new methodology towards 2,5-diarylthiophene-1-oxides, a key precursor to the Diels-Alder cycloaddition reaction. These reactive dienes are prepared from readily available arylacetylene precursors via zirconacyclopentadiene intermediates. The isolated yields of the desired thiophene-1-oxides are comparable to those obtained from previously established oxidation strategies while avoiding the formation of over-oxidation products. Of significant importance to scope of our work, this newly established methodology offers broader versatility providing products outfitted with electron-donating or electron-withdrawing groups. These new methodologies provided access to functionalized derivatives of the saddle-shaped molecule tetrabenzo[8]circulene in improved yield when coupled with a revised Diels-Alder/oxidative cyclodehydrogenation approach. This methodology affords products containing both electron-rich and electron-poor functional groups in a more efficient manner. The optoelectronic effects that result from the introduction of this functionality and investigations into the development of larger contorted aromatic systems are also discussed.

No description available.

Please read the abstract in the section 00front of this document / Thesis (PhD (Applied Science: Chemistry))--University of Pretoria, 2007. / Chemistry / unrestricted

This thesis discusses methods for the comparatively mild covalent functionalization of graphene. Several graphene models were investigated: polycyclic aromatic hydrocarbons (PAHs), chemical vapor deposition (CVD)-graphene on SiO2/Si substrate, graphite foil, graphite flakes, kish graphite and highly oriented pyrolytic graphite. The PAHs were viewed as graphene edge analogs with the following molecules representing different edge motifs: pyrene, perylene, benzo[a]pyrene, benzo[e]pyrene, triphenylene, acenapthylene, and anthracene. Ozone was used in combination with different solvents to functionalize PAHs, graphite, and CVD-graphene on SiO2/Si. Ozonation in water or methanol resulted in trapping of the carbonyl oxide intermediate that was formed in the reaction, producing a variety of functional groups. Ozonation in hydrogen peroxide solution with sonication promoted radical formation, possibly resulting in edge-oxidation of graphite. The regioselectivity for addition reactions (ozonolysis) and electrophilic aromatic substitution reactions with graphene edges is discussed. To achieve functionalization of the basal plane of graphite or graphene, white light irradiation was used in combination with several transfer hydrogenation reagents. Formic acid treatment under irradiation resulted in the expected hydrogenation, whereas iso-propanol treatment resulted in iso-propanol attachment to the graphene. The developed methods provide opportunities for graphene functionalization without the need for metal based reagents or harsh conditions.

L'asthme allergique est caractérisé par une réponse prédominante de typeTh2, mais d'autres profils tels que Th17 et Th22 sont aussi observés dans l'asthme plus sévère. La pollution atmosphérique et notamment les hydrocarbures aromatiques polycycliques (HAP) contenus dans les particules d'échappement diesel (DEP) contribuent à l'augmentation de la prévalence de l'asthme et jouent un rôle adjuvant dans le développement et l'exacerbation de l'inflammation allergique en orientant la réponse immune vers un profil Th2Dans la première partie de la thèse, nous avons évalué les effets des HAP sur la polarisation Th17/Th22 de PBMC de sujets allergiques asthmatiques et sujets non-allergiques. Les PBMC de patients asthmatiques présentent une augmentation des profils Th17/Th22 par rapport aux sujets non-allergiques. La stimulation par DEP-HAP et le benzo [a] pyrène (B[a]P) induit une augmentation de l’IL-22 mais de façon étonnante diminue la production d'IL-17A dans les deux groupes. Les facteurs de transcription associés aux cellules Th17: RORA et RORC, sont diminués, alors que le gène cible d’AhR, CYP1A1, est augmenté dans les deux groupes. Notch est diminué uniquement chez les patients asthmatiques. La production d'IL-22 induite par les HAP provient principalement de cellules Th22. L'antagoniste d’AhR reverse presque complètement les effets des DEP, mais seulement partiellement les effets de B[a]P, sur la regulation réciproque entre IL-22/IL-17. Les kinases PI3K, JNK et ERK participent à l’augmentation de l’IL-22 induite par le B[a]P, alors que la p38 MAP kinase a un effet inhibiteur. La deuxième partie de la thèse a évalué l'effet combiné des PRRs et des allergènes sur l’activation et leur capacité à induire une polarisation Th17/Th22 chez des sujets sains et des sujets allergiques asthmatiques. Les DCs stimulées par les allergènes de chien induisent une faible production d'IL-22 par les cellules T. L’activation supplémentaire par les ligands de TLR3, TLR9 et NOD2 conduit à une augmentation de la production augmentée de chimiokines pro-Th2 uniquement par les DCs de patients asthmatiques allergiques aux chiens. 7 A l’inverse, un rôle adjuvant est observé sur la maturation et la production de cytokines pro-Th17/Th22 par les DCs de sujets asthmatiques et de sujets non-allergiques. Parmi les cellules T co-cultivées avec des DC stimulées par l'allergène de chien et les ligands de PRR, nous observons un mélange de cellules de type Th2/Th17 et Th22 chez les patients asthmatiques et un profil Th1/Th22 chez les sujets non-allergiques. L’IL-22 est principalement produite par les Th22 dans les deux groupes avec plus de cellules Th22 observés chez les sujets asthmatiques. L’IL-17 et l’IL-22 sont régulées différemment entre les sujets asthmatiques et les sujets sains, le TGF-β ayant un rôle pro-Th17 tandis que l'IL-23 a un rôle pro-Th22. In vivo, un modèle d'asthme chronique induite par l’allergène de chien a été développé et conduit à une augmentation de la résistance des voies aériennes, une production de chimiokines Th2 et de cytokines Th2/Th17/Th22 ainsi qu’au recrutement de neutrophiles mais peu d’éosinophiles dans le poumon. L'expression du gène de l'IL-22 intervient de façon précoce alors que la protéine apparait plus tard. Le ligand de NOD2 induit une augmentation de la résistance des voies aériennes, ainsi que de la production de protéines et l'expression des gènes induits par l'allergène de chien, mais réduit le recrutement des éosinophiles dans les poumons. Ces résultats montrent que chez l'homme, les productions d’IL-22 et d'IL-17 sont régulées différemment entre les sujets asthmatiques allergiques et les sujets sains. Au total, la pollution et certaines infections bactériennes ou virales pourraient participer chez les patients asthmatiques à sévérité de la maladie et la progression du remodelage des voies aériennes. La modèle in vivo développée permettra de mieux disséquer les mécanismes qui participent à la sévérité de l'asthme. / Allergic asthma is characterized by a predominant Th2 response, but additional profiles such as Th17 and Th22 are observed in more severe asthma. Components of the air pollution such as polycyclic aromatic hydrocarbons (PAH) contained in diesel exhausts particles (DEP) contributes to increased prevalence of asthma and play an adjuvant role in the development and exacerbation of allergic inflammation through the skewing of the immune response towards a Th2 profile. In the first part of the thesis, we evaluated the effects of PAH on the Th17/Th22 polarization of PBMCs from healthy and allergic asthmatic subjects, PBMCs from athmatic patients exhibited an increased Th17/Th22 profile compared with non-allergic subjects. DEP-PAH and Benzo[a]Pyrene (B[a]P) stimulation further increased IL-22 but surprisingly decreased IL-17A production in both groups. Th17 transcription factors RORA and RORC were down regulated, whereas AhR target gene CYP1A1 was up-regulated in both groups. Notch was decreased only in asthmatic patients. PAH-induced IL-22 production originated mainly from Th22 cells. The AhR antagonist reversed almost completely the effects of DEP-PAH, but only partially the effects of B[a]P, on IL-22/IL-17 reciprocal regulation. The kinases PI3K, JNK and ERK participated to the enhancing effect of B[a]P on IL-22 production, whereas p38 MAP kinase had an inhibitory effect.The second part of the thesis evaluated the co-stimulatory effect of combined PRR- and allergen-activated DCs on Th17/Th22 polarization in healthy and asthmatic subjects. Dog allergen stimulated DCs induced a small production of IL-22 in T cells. Additional activation by TLR3, TLR9 and NOD2 ligands led to increased production of pro-Th2 chemokines by DCs only from asthmatic patients allergic to dogs. In contrast, an adjuvant role was observed on the maturation and pro-Th17/Th22 cytokines production by DCs from both asthmatic and non-allergic subjects. In T cells co-cultured with DCs stimulated by dog allergen and PRR ligands, we found a mixed Th2/Th17/Th22 profile in asthmatic patients and a Th1/Th22 profile in non-allergic subjects. IL-22 producing cells were mainly Th22 in both groups with more Th22 cells were observed in asthmatic subjects. IL-17 and IL-22 production was9differently regulated between asthmatic subjects and non-allergic subjects, TGF-β having a pro-Th17 role while IL-23 having a pro-Th22 role.In vivo, a model of chronic dog-induced asthma was developed leading increased airway resistance, Th2 chemokine and Th2/Th17/Th22 cytokine production as well as neutrophil but little eosinophil recruitment in the lung. Gene expression of IL-22 was observed at early time points whereas IL-22 protein appeared later on. NOD2 ligand further increased airway resistance, protein production and gene expression induced by dog allergen challenge but inhibited the small eosinophil recruitment in the lung.These results show that in humans, IL-17 and IL-22 productions are regulated differently between allergic asthmatic and non-allergic subjects. Altogether, pollution and some bacterial or viral infections may contribute in asthmatic patients to the severity of the disease and to progression of airway remodeling. The developed in vivo model will allow dissecting the mechanisms participating to the severity of asthma.

Orientador: Lucia Regina Durrant, Matthew James Grossman / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-22T02:43:16Z (GMT). No. of bitstreams: 1 Santos_LigiaGibinidos_M.pdf: 3848321 bytes, checksum: 46f91a01a783f6fd7d5153ba73c6e8a0 (MD5) Previous issue date: 2013 / Resumo: Dentre os contaminantes ambientais mais abundantes, destacam-se os Hidrocarbonetos aromáticos policíclicos (HAPs), que apresentam elevado potencial tóxico, sendo imprescindível sua remoção do ambiente. O objetivo deste trabalho foi analisar, em microcosmos, a biodegradação de HAPs por um consórcio bacteriano e identificar fatores que influenciam nesta degradação e na análise dos dados. A degradação dos HAPs no solo sem histórico de contaminação foi muito semelhante em todos os microcosmos, apresentando uma porcentagem de aproximadamente 85%. Para analisar a toxicidade do solo antes e depois da biorremediação, realizou-se um testes de germinação de sementes de Lactuca sativa (alface). O teste mostrou baixa toxicidade do solo após 80 dias da contaminação, com ou sem a adição do consórcio. Durante estudos de remediação biológica, é necessário utilizar um marcador interno para minimizar a dispersão e extração irregulares dos contaminantes. Neste estudo foi utilizado o hexaclorobenzeno, que mostrou excelente, uma vez que não sofreu nenhum tipo de degradação. Análises moleculares mostram que a adição de HAPs alterou significativamente a comunidade microbiana, favorecendo os membros degradadores de tais poluentes. O consórcio adicionado inibiu o crescimento de alguns micro-organismos autóctones. Além disso, não houveram evidências de que os micro-organismos degradadores de HAPs adicionados persistiram, sugerindo que eles podem não competir eficientemente com a população microbiana autóctone. Não houve efeito claramente identificado do hexaclorobenzeno sobre o crescimento de micro-organismos, com exceção de um aumento no número de organismos pertencentes da classe Alphaproteobacteria / Abstract: Polycyclic aromatic hydrocarbons (PAHs) stand out as among the most abundant and toxic of environmental contaminants, and their removal from contaminated sites is indispensable for a healthy environment. The objective of this study was to analyze, in soil microcosms, the biodegradation of PAHs by a bacterial PAH degrading consortium and identify factors that influence this degradation and data analysis. Degradation of PAHs in soil with no history of contamination was very similar in microcosms with or without bioaugmentation, with the extent of PAH removal of about 85% in all cases. The germination of Lactuca sativa (lettuce) in soils taken from the microcosms was used to examine the toxicity of the soil before and after bioremediation. The test showed a low toxicity of the soil 80 days after PAH contamination, with or without the addition of the consortium. During studies of biological remediation it is necessary to use an internal non-biodegradable marker to minimize the effect of uneven dispersion and irregular extraction of pollutants. This study used hexachlorobenzene as the nonbiodegradable marker and it proved to be an excellent marker as it did not suffer any significant degradation in the soil microcosms. Molecular analyzes showed that the addition of PAHs significantly altered the microbial community by encouraging the growth of PAH degraders. In addition, the added microbial consortium was found to inhibit the growth of some of the indigenous microorganisms. Furthermore, there was no evidence that the added PAH degraders persisted, suggesting that they might not compete effectively with the native microbial population. There was little effect of hexachlorobenzene on the microbial community or on the removal of the PAH contaminants, with the exception of an increase in the number of organisms belonging to the class Alphaproteobacteria / Mestrado / Ciência de Alimentos / Mestra em Ciência de Alimentos

Routine monitoring of environmental pollution demands simplicity and speed without sacrificing sensitivity or accuracy. The development and application of sensitive, fast and easy to implement analytical methodologies for detecting emerging and traditional water and airborne contaminants in South Florida is presented. A novel method was developed for quantification of the herbicide glyphosate based on lyophilization followed by derivatization and simultaneous detection by fluorescence and mass spectrometry. Samples were analyzed from water canals that will hydrate estuarine wetlands of Biscayne National Park, detecting inputs of glyphosate from both aquatic usage and agricultural runoff from farms. A second study describes a set of fast, automated LC-MS/MS protocols for the analysis of dioctyl sulfosuccinate (DOSS) and 2-butoxyethanol, two components of Corexit®. Around 1.8 million gallons of those dispersant formulations were used in the response efforts for the Gulf of Mexico oil spill in 2010. The methods presented here allow the trace-level detection of these compounds in seawater, crude oil and commercial dispersants formulations. In addition, two methodologies were developed for the analysis of well-known pollutants, namely Polycyclic Aromatic Hydrocarbons (PAHs) and airborne particulate matter (APM). PAHs are ubiquitous environmental contaminants and some are potent carcinogens. Traditional GC-MS analysis is labor-intensive and consumes large amounts of toxic solvents. My study provides an alternative automated SPE-LC-APPI-MS/MS analysis with minimal sample preparation and a lower solvent consumption. The system can inject, extract, clean, separate and detect 28 PAHs and 15 families of alkylated PAHs in 28 minutes. The methodology was tested with environmental samples from Miami. Airborne Particulate Matter is a mixture of particles of chemical and biological origin. Assessment of its elemental composition is critical for the protection of sensitive ecosystems and public health. The APM collected from Port Everglades between 2005 and 2010 was analyzed by ICP-MS after acid digestion of filters. The most abundant elements were Fe and Al, followed by Cu, V and Zn. Enrichment factors show that hazardous elements (Cd, Pb, As, Co, Ni and Cr) are introduced by anthropogenic activities. Data suggest that the major sources of APM were an electricity plant, road dust, industrial emissions and marine vessels.

Several different mechanisms leading to the formation of (substituted) naphthalene and azanaphthalenes were examined using theoretical quantum chemical calculations. As a result, a series of novel synthetic routes to Polycyclic Aromatic Hydrocarbons (PAHs) and Nitrogen Containing Polycyclic Aromatic Compounds (N-PACs) have been proposed. On Earth, these aromatic compounds originate from incomplete combustion and are released into our environment, where they are known to be major pollutants, often with carcinogenic properties. In the atmosphere of a Saturn’s moon Titan, these PAH and N-PACs are believed to play a critical role in organic haze formation, as well as acting as chemical precursors to biologically relevant molecules. The theoretical calculations were performed by employing the ab initio G3(MP2,CC)/B3LYP/6-311G** method to effectively probe the Potential Energy Surfaces (PES) relevant to the PAH and N-PAC formation. Following the construction of the PES, Rice-Ramsperger-Kassel-Markus (RRKM) theory was used to evaluate all unimolecular rate constants as a function of collision energy under single-collision conditions. Branching ratios were then evaluated by solving phenomenological rate expressions for the various product concentrations. The most viable pathways to PAH and N-PAC formation were found to be those where the initial attack by the ethynyl (C2H) or cyano (CN) radical toward a unsaturated hydrocarbon molecule led to the formation of an intermediate which could not effectively lose a hydrogen atom. It is not until ring cyclization has occurred, that hydrogen elimination leads to a closed shell product. By quenching the possibility of the initial hydrogen atom elimination, one of the most competitive processes preventing the PAH or N-PAC formation was avoided, and the PAH or N-PAC formation was allowed to proceed. It is concluded that these considerations should be taken into account when attempting to explore any other potential routes towards aromatic compounds in cold environments, such as on Titan or in the interstellar medium.