ABSTRACT Hydrophobic organic pollutants (HOPs) are in general characterized by high toxicity, long environmental half-life and high bio-accumulation factors. Due to their hydrophobicity, HOPs tend to sorb onto particles in environment. The influence of the dissolved organic matters (DOMs) on the sorption partition coefficient is observed because of their interactions with HOPs. This binding between DOM and HOPs increases apparent solubility and mobility of the HOPs in natural aquatic system. On the purpose of obtaining data closer to the real world, many aquatic factors, such as the concentration and types of DOM, pH value and ionic strength, are studied intensively recently. There are many studies about the mechanisms in the association of DOM and HOPs. Most of them assume achievement of equilibrium in their measurement. Recently, it was reported (Engebretson and von Wandruszka, 1998) that slow, revering, and even oscillating kinetics are observed. It is great concern and interest to those related studies in literatures. Complicated kinetic may in fact be a cause of the reproducibility problems for measurements of HOPs associated with both humic acid and metals. As such, by monitoring fluorescence intensity, we investigate the equilibrium kinetic of pyrene in HA solutions. In this study, results show that there are two stages of the fluorescence intensity after pyrene spiked into HA solutions: First, the fluorescence intensity decreases steeply due to the first dispersion of pyrene and the reaction of pyrene and HA (the front is dominance). Secound, fluorescence intensity decreases gently because of wall-effect. The dispersion rate of pyrene in HA solutions is difference with HA molecular size and quantity. As the ionic strength rising, cations reacting with specific binding sites on HA, the molecules¡¦ configuration of HA is changed, and less obstruct for dispersing of pyrene. It works as well as little molecular quantity. For second stage when ionic strength rising, wall- associations is less because of the hydrophobic-binding of pyrene and LHA is more stronger. Furthermore, it is not observed the ¡§migration¡¨ of Mg2+ within the LHA molecular structure as described by Engebretson and von Wandruszka .The reasons that make different results may depend on the species of humic acid. Therefore, the observations of Engebretson and von Wandruszka could not be used directly questioning those results in literatures. In addition, the effects of various cations (Mg2+, Ca2+and Sr2+) on Kdom are studied. It is believed different cation reacts with different specific binding sites on HA. As such, both charge density and affinity of cation with specific binding sites on HA should be considered in discussing the effects of metal ionic on the binding constants between PAHs and DOM.

Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the environment and are generated by many sources. Though the potential of PAH-rich mixtures to cause health effects has been known for almost a century, there are still unanswered questions about the levels of PAHs in the environment, the potential for human exposure to PAHs, the health effects associated with exposure, and how genetic susceptibility influences the extent of health effects in individuals. The first objective of this research was to quantify concentrations of PAHs in samples of settled house dust collected from homes in Azerbaijan, China, and Texas. The trends of PAH surface loadings and percentage of carcinogenic PAHs were China > Azerbaijan > Texas, indicating that the risk of health effects from exposure to PAHs in house dust is highest in the Chinese population and lowest in the Texas population. PAHs in China and Azerbaijan were derived mainly from combustion sources; Texas PAHs were derived from unburned fossil fuels such as petroleum. The second objective of this research was to investigate the effect of pregnane X receptor (PXR) on the genotoxicity of benzo[a]pyrene (BaP). BaP treatment resulted in significantly lower DNA adduct levels in PXR-transfected HepG2 cells than in parental HepG2 cells. Total GST enzymatic activity and mRNA levels of several metabolizing enyzmes were significantly higher in cells overexpressing PXR. These results suggest that PXR protects cells against DNA damage by PAHs such as BaP, possibly through a coordinated regulation of genes involved in xenobiotic metabolism. The third objective of this research was to investigate biomarkers of exposure in house mice (Mus musculus) exposed to PAH mixtures in situ. Mice and soil were collected near homes in Sumgayit and Khizi, Azerbaijan. Mean liver adduct levels were significantly higher in Khizi than in Sumgayit. Mean lung and kidney adduct levels were similar in the two regions. The DNA lesions detected may be a combination of environmentally-induced DNA adducts and naturally-occurring I-compounds. PAHs were present at background levels in soils from both Khizi and Sumgayit. It appears that health risks posed to rodents by soil-borne PAHs are low in these two areas.

The self-assembly of several pyrene-labelled amphiphilic macromolecules in water was characterized by fluorescence. Information on their self-assembly was obtained by monitoring the level of pyrene aggregation in solution. A measure of the level of association was obtained by determining the fraction of aggregated pyrene of the labelled macromolecules from the global analysis of their monomer and excimer fluorescence decays. Global analysis limits the degrees of freedom of the analysis thus reducing the error on the parameters retrieved from the analysis. Extensive developments in the global analysis of the pyrene monomer and excimer decays enabled the first characterization of the molar absorbance coefficient of the pyrene aggregates formed by aqueous solutions of pyrene-labelled poly(N,N-dimethylacrylamide) (PyPDMA) and poly(ethylene oxide) (PyPEO). The molar absorbance coefficients of the pyrene aggregates determined for PyPDMA and PyPEO were both found to be broader and red-shifted compared to that of unaggregated pyrene. These results agree with observations found in the scientific literature made by using absorption and excitation fluorescence measurements. Attempts to determine the molar absorbance coefficient of pyrene-labelled hydrophobically-modified alkali-swellable emulsion (PyHASE) polymers were unsuccessful. The inability to characterize the pyrene aggregates of PyHASE was attributed to the greater complexity of the PyHASE polymer compared to PyPDMA and PyPEO. For these simpler pyrene-labelled polymers, a protocol has been established which uses the global analysis of the pyrene monomer and excimer decays to determine quantitatively the level of association of pyrene-labelled polymers as well as the molar absorbance coefficient of their aggregates. Changes in the level of aggregation of pyrene-labelled lipids (PLLs) having head groups bearing an alcohol (PSOH) or imido diacetic acid (PSIDA) embedded in 1-palmitoyl-2-oleyl-3-sn-phosphatidylcholines (POPC) or distearylphosphatidylcholine (DSPC) liposomes were probed by fluorescence. Distribution of the PLLs in the fluid POPC membrane was found to be homogeneous while the PLLs phase-separated into amorphous channels created in the DSPC membranes. Multivalent cations Cu2+ and La3+ were found to bind to PSIDA, hindering diffusional encounters between unaggregated PSIDA but leaving the PLL aggregates intact. Using the fluorescence quenching ability of Cu2+, the viscosity of the amorphous channels of the DSPC membrane was determined to be about six times greater than that of the more fluid POPC membrane. Simultaneous rheological and fluorescence measurements were achieved by interfacing a rheometer with time-resolved and steady-state fluorometers using fiber-optic cables. This joint set up enabled the simultaneous rheological and fluorescence measurements of PyHASE solutions having concentrations ranging from 0.5 w/w% to 5 w/w%. The level of association of the PyHASE solutions was tracked using fluorescence at shear rates of 0, 0.1 and 100 s–1. Despite the presence of shear thinning leading to viscosity drops of up to four orders of magnitude, no change in the fluorescence and hence the level of association was observed. The lack of change in level of association implied that the mechanism of shear thinning is due to a switching from inter- to intramolecular association rather than a drop in the level of association. This information will prove useful for future models attempting to predict the rheological behaviour of sheared associative polymers.

Submitted by André Chamelete null (andre_ecco@hotmail.com) on 2016-02-12T14:02:00Z No. of bitstreams: 1 Dissertação de Mestrado - FINAL.pdf: 663322 bytes, checksum: 5ca648d67a3a798d08f9c68653ac3ca2 (MD5) / Approved for entry into archive by Sandra Manzano de Almeida (smanzano@marilia.unesp.br) on 2016-02-12T17:20:57Z (GMT) No. of bitstreams: 1 chamelete_a_me_sjrp.pdf: 663322 bytes, checksum: 5ca648d67a3a798d08f9c68653ac3ca2 (MD5) / Made available in DSpace on 2016-02-12T17:20:57Z (GMT). No. of bitstreams: 1 chamelete_a_me_sjrp.pdf: 663322 bytes, checksum: 5ca648d67a3a798d08f9c68653ac3ca2 (MD5) Previous issue date: 2016-01-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O BaP é um contaminante ambiental capaz de causar inflamação e desregulação de vias celulares. Pela ação da CYP1a1 e CYP1b1, é convertido a metabólitos mais reativos. A literatura mostra que o BaP aumenta a expressão de algumas citocinas próinflamatórias, como a IL-1, porém, são bem contraditórios os relatos sobre o efeito do BaP no cFOS, o qual apresenta papel importante na proliferação, na formação de tumores e, possivelmente, na inflamação. O objetivo deste estudo foi de elucidar a participação do receptor purinérgico P2X7 sobre a expressão dos genes IL-1 e cFOS, durante exposição ao BaP. Foi empregado as técnicas de qPCR para quantificação de expressão gênica, e testes de correlação e regressão entre IL-1 e cFOS. A exposição ao BaP induziu a expressão dos dois genes, além das enzimas do seu metabolismo. Quando bloqueado o receptor P2X7, além de uma menor indução das CYPs, os níveis de IL-1 e cFOS caíram abaixo dos níveis controle, sugerindo a participação do P2X7. Os testes de correlação e regressão mostraram uma relação forte direta entre IL-1 e cFOS, reforçando o papel do cFOS na inflamação. / BaP is an environmental contaminant capable to cause inflammation and impair cellular pathways. CYP1a1 and CYP1b1 convert it to more reactive metabolites. Studies show that BaP enhances some proinflammatory citokines expression, like IL-1, yet reports about BaP affecting cFOS, which plays important role in proliferation, tumor formation and inflammation, are controversial. This work aimed to elucidate whether P2X7 purinergic receptor plays a role in IL-1 and cFOS expression during BaP exposure. We applied qPCR techniques to quantify gene expression, correlation and regression assays. Our results showed that BaP raised both IL-1 and cFOS genes expression, besides CYPs ones. Morevoer, when blocking P2X7 receptor, IL-1 and cFOS expression dropped under normal levels, which suggest P2X7 participation, in addition to a smaller enzymes induction. Correlation and regression assays exhibited a strong straight relationship between IL-1 and cFOS expression, reinforcing the role of cFOS in inflammation.

Neste trabalho, duas amostras de turfa (uma decomposta - TD, e outra fibrosa - TF), foram caracterizadas através de várias técnicas instrumentais, incluindo a microscopia eletrônica de varredura (MEV), a análise elementar (CHNS), a análise termogravimétrica (TG), a espectroscopia de infravermelho com Transformada de Fourier (FT-IR) e a espectroscopia de ressonância magnética nuclear de 13C no estado sólido (RMN 13C). Após a caracterização, essas amostras foram utilizadas em ensaios de adsorção para a avaliação do potencial de remoção das turfas frente ao contaminante pireno em meio aquoso. De modo geral, os resultados revelaram que ambas as amostras são estruturalmente muito semelhantes entre si. Com relação ao processo de adsorção do pireno pelas duas amostras em solução aquosa, foi possível verificar que o mesmo apresentou elevada eficiência, atingindo 91% de remoção para a TD e 92% para a TF. Além disso, o processo de adsorção parece ocorrer em múltiplas camadas, uma vez que dentre as isotermas de adsorção avaliadas, o modelo de Freundlich foi o que melhor se ajustou aos dados experimentais. A cinética de adsorção foi avaliada por meio das equações de pseudoprimeira ordem e pseudossegunda ordem, sendo o segundo mecanismo mais adequado para avaliar o processo. Dados termodinâmicos revelaram que a adsorção do pireno pelas amostras de turfa é um processo espontâneo nas condições experimentais utilizadas. Finalmente, os resultados obtidos mostram que a eficiência de remoção associada às amostras de turfa abre perspectivas para a sua utilização na remoção desse contaminante de soluções aquosas. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-05T16:58:06Z No. of bitstreams: 1 Dissertacao Francine Girardello.pdf: 2105923 bytes, checksum: 51f7694767b4afd1bc6e98c73a560493 (MD5) / Made available in DSpace on 2014-06-05T16:58:06Z (GMT). No. of bitstreams: 1 Dissertacao Francine Girardello.pdf: 2105923 bytes, checksum: 51f7694767b4afd1bc6e98c73a560493 (MD5) / In this study, two peat samples (one decomposed DP, and another fibrous FP) were characterized by several instrumental techniques, including scanning electron microscopy (SEM), elemental analysis (CHNS), thermogravimetric analysis (TGA), Fourier Transform infrared (FT-IR) spectroscopy, and 13C solid-state nuclear magnetic resonance (13C NMR). These same samples were later used in adsorption tests for assessing the potential removal of peat against the pyrene contaminant. Although the TF present some vegetable structures newer than the TD, the results revealed that both samples are structurally very similar. Regarding the adsorption of pyrene by two samples in aqueous solution, it was possible to verify that it has a high efficiency, reaching 91% removal for the TD and 92% for TF, respectively. In addition, the adsorption process seems to occur in multiple layers, once among the measured adsorption isotherms, the Freundlich model was the best fit to experimental data. The adsorption kinetics was assessed by means of pseudo first and pseudo second order equations, being the second most appropriate mechanism to evaluate the process. Thermodynamic data revealed that the adsorption of pyrene by the peat samples is a spontaneous process under these experimental conditions. Finally, the results show that the removal efficiency associated with the peat samples opens perspectives for its use in removing this contaminant from aqueous solutions.

Neste trabalho, duas amostras de turfa (uma decomposta - TD, e outra fibrosa - TF), foram caracterizadas através de várias técnicas instrumentais, incluindo a microscopia eletrônica de varredura (MEV), a análise elementar (CHNS), a análise termogravimétrica (TG), a espectroscopia de infravermelho com Transformada de Fourier (FT-IR) e a espectroscopia de ressonância magnética nuclear de 13C no estado sólido (RMN 13C). Após a caracterização, essas amostras foram utilizadas em ensaios de adsorção para a avaliação do potencial de remoção das turfas frente ao contaminante pireno em meio aquoso. De modo geral, os resultados revelaram que ambas as amostras são estruturalmente muito semelhantes entre si. Com relação ao processo de adsorção do pireno pelas duas amostras em solução aquosa, foi possível verificar que o mesmo apresentou elevada eficiência, atingindo 91% de remoção para a TD e 92% para a TF. Além disso, o processo de adsorção parece ocorrer em múltiplas camadas, uma vez que dentre as isotermas de adsorção avaliadas, o modelo de Freundlich foi o que melhor se ajustou aos dados experimentais. A cinética de adsorção foi avaliada por meio das equações de pseudoprimeira ordem e pseudossegunda ordem, sendo o segundo mecanismo mais adequado para avaliar o processo. Dados termodinâmicos revelaram que a adsorção do pireno pelas amostras de turfa é um processo espontâneo nas condições experimentais utilizadas. Finalmente, os resultados obtidos mostram que a eficiência de remoção associada às amostras de turfa abre perspectivas para a sua utilização na remoção desse contaminante de soluções aquosas. / In this study, two peat samples (one decomposed DP, and another fibrous FP) were characterized by several instrumental techniques, including scanning electron microscopy (SEM), elemental analysis (CHNS), thermogravimetric analysis (TGA), Fourier Transform infrared (FT-IR) spectroscopy, and 13C solid-state nuclear magnetic resonance (13C NMR). These same samples were later used in adsorption tests for assessing the potential removal of peat against the pyrene contaminant. Although the TF present some vegetable structures newer than the TD, the results revealed that both samples are structurally very similar. Regarding the adsorption of pyrene by two samples in aqueous solution, it was possible to verify that it has a high efficiency, reaching 91% removal for the TD and 92% for TF, respectively. In addition, the adsorption process seems to occur in multiple layers, once among the measured adsorption isotherms, the Freundlich model was the best fit to experimental data. The adsorption kinetics was assessed by means of pseudo first and pseudo second order equations, being the second most appropriate mechanism to evaluate the process. Thermodynamic data revealed that the adsorption of pyrene by the peat samples is a spontaneous process under these experimental conditions. Finally, the results show that the removal efficiency associated with the peat samples opens perspectives for its use in removing this contaminant from aqueous solutions.

In this experiment, fluorescent N- (1-pyrenyl) iodoacetamide modified the two reactive thiols, SH1 (Cys 707) and SH2 (Cys 697) on myosin to detect SH1-SH2 a -helix melting. The excimer forming property of pyrene is well suited to monitor the dynamics of the SH1 and SH2 helix melting, since the excimer should only form during the melted state. Decreased anisotropy of the excimer relative to the monomeric pyrene fluorescence is consistent with the disordering of the melted SH1-SH2 region in the atomic model. Furthermore, nucleotide analogs induced changes in the anisotropy of the excimer, suggesting that the nucleotide site modulates the flexibility of SH1-SH2 region.

Photophysical properties of an array of various polyaromatic hydrocarbons were benchmarked with B3LYP, M06 and B97D methods coupled with Pople and CEP-31G(d) basis sets. Results from the benchmark show the importance of diffuse basis sets when modeling the electronic properties of highly conjugated systems and provide qualitative reliable accuracy with certain levels of theory. B97D and M06 are applied to modeling pyrene adducts governed by non-covalent interactions in both gaseous and condensed states to reproduce experimental spectra. DFT calculations with both B97D and M06 functionals show qualitatively and quantitatively that pyrene dimer is a stronger π–base as compared to its monomer. Binding energies coupled with MEP, PCA and Qzz results show that the difference in π-basicity of the monomer and dimer impacts the supramolecular chemistry involved in adducts formed with super π-acidic silver cyclometallic trimer (CTC). Non-covalent interactions between coinage metal CTCs and ammonia/phosphine substrates is reported. Interactions between these substrates and the facial plane of the π-rich gold CTC reveal a novel interaction, where the typical Lewis acid/base roles are reversed for the substrates. Adducts formed through this type of interaction define typical Lewis bases like ammonia and phosphine as Lewis acids, wherein the partially positive hydrogens coordinate to the metallo-aromatic center through dipole-quadrupole interactions. Interactions of ammonia at the side positions is shown to heavily impact the Lewis basicity of the CTC facial plane leading to similar interactions exhibited by the ammonia-gold CTC adducts. Structural and electronic properties of the adducts modeled are examined.

Soot formation mechanisms have been a target of intense research for decades. The various stages in the soot formation mechanism have been accepted and recognized, nevertheless, the nucleation stage, which corresponds to the transition from gas phase polycyclic aromatic hydrocarbons (PAH) to condensed particles, is controversial. Pyrene dimerization is considered by many models to be the first step in soot nucleation. In this work, a jet-stirred reactor (JSR) in the temperature range of 700 – 1200 K was used to perform pyrene pyrolysis and to study the various dimerization Nascent particles were chemically analyzed using Fourier-transform ion cyclotron resonance high resolution mass spectrometry (FT-ICR MS) with a laser desorption ionization (LDI) source. Simulations were realized based on a simple kinetic model using CHEMKIN-PRO, which addressed three different dimerization pathways: 1) physical dimerization of two pyrene molecules (P-DIM), 2) physical dimerization between a pyrene molecule and a pyrenyl radical (PR-DIM), and/or 3) chemical dimerization between two pyrenyl radicals (C-DIM). The detected species presented 202 and 402 Da masses in the mass spectra with different intensities. At higher temperatures, the formation rate was enhanced due to the sensibility of particle formation to the reaction temperature. The first temperature regime was identified at 700 – 900 K, where the detected species contained only pyrene molecules, stacked by Van der Waals forces (P-DIM). In the 900–1100 K range, the formation of pyrenyl radicals was considered, and the production of PR-DIM was favored. In the higher temperature range (1100–1200 K), the greater species' mass were located and related to the dimerization of two pyrenyl radicals (C-DIM). The temperature increase was reflected in the production of higher concentrations of the pyrenyl radical, resulting in the dominance of the chemical dimerization pathway at 1200 K. The use of different initial concentrations of pyrene in the simulations did not significantly affect the outcome. Results of the experiment were reflected in the simulations, based on the model used, revealing the tendency of the three dimerization pathways, the decreased survival rate of physically-formed dimers, and the enhanced production of chemically-linked dimers at high temperatures.

Two indole-based squaraine dyes bonded to two pyrenyl groups through vinyl- and ethynyl- linkers were synthesized with the aim of enhancing the intramolecular charge transfer interaction in addition to improving their optical properties. The absorption and emission properties of these derivatives were determined in order to gain an insight into the intensity of this type of interaction, their aggregation behavior and compare them with results obtained through quantum chemical calculations. Both compounds presented high photochemical stability in THF, and the linear spectroscopic characterization revealed high extinction coefficients, large fluorescence quantum yields and relatively low tendency of forming excimers in several solvents. The nonlinear spectroscopic study revealed two-photon absorption cross section maxima greater than 10,000 GM (1 GM = 1 × 10-50 cm4 s/photon), which are improved values in comparison with the indole-based squaraine core. The experimental results were compared with time-dependent DFT calculations. These observations propose a new trend in the formulation of highly absorbing organic molecules containing pyrenyl groups for the development of new materials with Organic Light-Emitting Diode (OLED) applications. Moreover, this work contributes to the study of intramolecular charge transfer interaction and its tailoring for the improvement of the linear and nonlinear optical properties.