Orientador: Raquel Fernandes Pupo Nogueira / Banca: Sofia Nikolaou / Banca: Rose Mary Zumstein Georgetto Naal / Resumo: O estudo de interferentes endócrinos em águas tem sido relevante devido aos efeitos deletérios promovidos por estes compostos, encontrados no ambiente em baixíssimas concentrações, na faixa de ng L-1 até μg L-1. Hormônios estrógenos são importantes interferentes endócrinos. Neste trabalho, foi avaliada a influência da β- ciclodextrina (β-CD) na degradação dos hormônios estrógenos 17β-estradiol (E2) e 17α-etinilestradiol (EE2) por processo Fenton e foto-Fenton, com irradiação artificial. Por meio de métodos espectrofotométricos, determinou-se que a estequiometria de inclusão de E2:β-CD e EE2: β-CD é 1:1, e a constante de inclusão assume valores da ordem de 103 L mol-1 para ambos os hormônios. A constante de complexação Fe2+-β-CD apresentou maior valor em pH 4,0, quando comparados aos valores encontrados em pH 2,5 e 6,0. Já a constante de complexação Fe3+-β-CD foi maior em pH 6,0. A degradação de E2 e EE2 foi determinada por cromatografia líquida de alta eficiência (CLAE) e a mineralização por determinações de carbono orgânico total (COT). Foi observado que o processo Fenton (Fe2+ = 0,01 mmol L-1 e H2O2 = 0,5 mmol L-1) em pH 2,5 e 4,0 reduziu a concentração do EE2 a valores abaixo do limite de detecção do equipamento após 90 minutos de reação e em pH 6,0, a redução na concentração alcançou somente 50% após o mesmo tempo; entretanto, não ocorreu a remoção do COT das amostras, indicando que houve a formação de intermediários de reação. Na presença de β-CD, a eficiência da reação de Fenton foi menor e a redução na concentração de EE2 chegou a cerca de 50% nos valores de pH testados. Novamente, não foi observada remoção do COT das amostras. Observou-se que a degradação do EE2 por processo foto-Fenton reduz a concentração do hormônio até abaixo do limite de detecção do equipamento após 30 minutos de reação... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The study of endocrine disruptors in water has been important due to the deleterious effects promoted by these compounds, found in the environment at very low concentrations. Estrogens are important endocrine disruptors. In this study, the influence of β-cyclodextrin (β-CD) in the degradation of the hormones estrogen 17β- estradiol (E2) and 17α-ethinylestradiol (EE2) by Fenton and photo-Fenton process using artificial irradiation was evaluated. Using spectrophotometric methods, it was determined that the stoichiometry of the inclusion of E2 and EE2 in β-CD is 1:1, and the inclusion constant assumes values around 103 L mol-1 for both hormones. The Fe2+-β-CD complexation showed the highest value at pH 4.0, which was compared to values found at pH 2.5 and 6.0. The Fe2+-β-CD complexation was higher at pH 6.0. The degradation of E2 and EE2 was determined by high performance liquid chromatography and mineralization by determination of total organic carbon (TOC). It was observed that the Fenton process (Fe2+ = 0,01 mmol L-1 e H2O2 = 0,5 mmol L-1) at pH 2.5 and 4.0 reduced the concentration of EE2 to values below the detection limit of the equipment after 90 minutes of reaction and at pH 6.0, the reduction in the concentration reaches only 50% after same time. However, the removal of TOC of the samples is not observed, indicating the formation of intermediates. In the presence of β-CD, the reaction efficiency is reduced and the reduction in the concentration of EE2 reaches about 50% at the pH values tested. Again, there was no mineralization of the samples. It was observed that the degradation of EE2 by photo-Fenton process reduces the concentration of the hormone to levels below the detection limit of the equipment after 30 minutes of reaction at pH 2.5 and 4.0 and about 60% degradation is observed after 60 minutes reaction at pH 6.0. The mineralization in these samples reached... (Complete abstract click electronic access below) / Mestre

<p> This creative research explores connections between the fields of scientific research, weapons proliferation and ceramic art making. My work consists of a twisted world of these themes seen and told through childhood imagery and subjects. The juxtaposition of violence and destruction against innocence and playfulness and the cyclical way that I engage both intuitively and through calculation with my artwork are vital in impressing a notion of conflict&rsquo;s early presence and danger in our lives. The overlap of weapons, chemistry and art is embodied in the relationships of the characters within these compositions and their iconographic meanings. This amalgamation is constructed through installations, sculptures and miniature models employing numerous kinds of ceramic and non-ceramic materials such as metal, wood, plastics and glass.</p><p> These works present conflict as similar to chemistry - omnipresent and unavoidable. The truths explored here feature a convoluted personal narrative, where family portraiture is seen through the lenses of our scientists and the imaginations of our children. Within the microcosmic worlds that the characters and environments in this work construct, the viewer is presented with simultaneous situations of destruction and unity. It is my intent through this imagery to lead my audience towards a greater appreciation of multiple views and non-binary biases.</p><p>

For genome integrity, adequate levels of deoxyribonucleotide (dNTPs) are essential to maintain faithful DNA replication and repair via the regulation of ribonucleotide reductase (RNR). In the fission yeast, RNR is composed of two subunits: Cdc22 and Suc22. The importance of Spd1 (RNR inhibitor) in Cdc22-Suc22 complex formation has been demonstrated by imaging of S. pombe containing fluorescent protein (FP) modified RNR subunit proteins in the presence of Spd1 and absence of Spd1 cells using confocal laser scanning microscopy. To investigate further the significant role of Spd1 in the regulation of RNR, 41 mutants created by Nestoras group. We used fluorescence resonance energy transfer (FRET) by acceptor photobleaching to investigate the RNR subunit interaction and provide evidence for a new model for the role of Spd1 in RNR regulation. Different treatments such as HU, 4NQO and heat shock have been used to investigate the effect of radical scavenging on the inhibition of RNR activity and induced DNA damage on S. pombe cell viability to elucidate further the role of Spd1 in the regulation of RNR. Finally a novel imaging technique, near-total internal reflection microscopy has been developed and applied with dual-view detection. The technique has been applied to image, simultaneously, the donor CFP and acceptor YFP channels of the FP-tagged RNR complex in the wild-type S. pombe cells and perform FRET measurements that are consistent with the confocal fluorescence results. In conclusion, a new hypothesis for the role of Spd1 has been drawn from the results, which is that the inhibitory role of Spd1 mediates the Suc22-Cdc22 (R1-R2) interaction to form a FRET competent but immature and inactive RNR complex, while with Spd1 deleted RNR is clearly active in a conformation that lacks FRET.

The work in this thesis deals with computational studies of manganese ions and atoms in the gas-phase and in the solid phase. The results are divided into three chapters, and the theory and methods used are explained and discussed in a separate theory chapter. The first results on manganese and its coordination to water and methanol molecules in the gas-phase are discussed in the light of physical properties for different ligands including water and methanol. Preferred coordination of a specific ligand type, preferred complex or cluster size as well as coordination modes are thoroughly investigated. Also discussed is stability against proton-transfer reactions for a few manganese-water and manganese-methanol clusters. The work is carried out at the HF/6- 31G(d), MP2/6-311G(d,p) and B3LYP/6-311(3df,3pd)-level of theory using the computer code Gaussian. The results presented here are in good agreement with experimental results and findings. It is concluded that mixing between 4s and 3d orbitals on the manganese atom is responsible for preference for a specific cluster size and that occupation of anti-bonding orbitals destabilizes the cluster, for a specific coordination mode. The next results are for manganese atoms in a double layer of graphite, using the computer code Aimpro. Different coordination modes are investigated as are magnetic properties upon adsorption and modification of the band structure compared to a pristine double layer of graphene. Only one case of a significantly high spin polarization is encountered, and the spin polarization on the manganese atom and the surrounding carbon atoms is investigated with Mulliken analysis. This study is in agreement with previous work in the same field, but provides a more realistic picture since a larger system is considered here. The final chapter deals with manganese atoms in metal-organic frameworks, MOFs, using the Aimpro code. Magnetic properties and binding energies for adsorption of selected molecules are discussed in this chapter. Magnetic properties are discussed using Mulliken analysis. Modification of the band structure upon coordination of these gas molecules is shown and investigated. Very few experimental results exist in this field for this structure, but its role as a potential candidate for hydrogen storage will specifically be discussed.

The primary objectives of this research were therefore to evaluate polybrominated diphenyl ether (PBDE) bioavailability to ecologically distinct soil invertebrates exposed to Penta-BDE-treated consumer polyurethane foam (PUF) products and biosolid products with incurred PBDEs. In laboratory bioassays, earthworms (Eisenia fetida) bioaccumulated SigmaPBDEs (47+99+100+183) up to 11,000 mug/kg lipid after 28 days from a mixture of artificial soil and anaerobically-digested sludge biosolid (ADB). Earthworms also bioaccumulated SigmaPBDEs (47+99+100+153+154+183) up to 13,500 and 838,000 mug/kg lipid after 28 d from a mixture of artificial soil and composted sludge biosolid (CB) and Penta-BDE-spiked artificial soil (SAS), respectively. No previous lab studies on bioaccumulation of PBDEs from sludge or sludge-amended soils have been published. Two publications, done by the same research group on the same sites in Sweden, do exist documenting incidental levels of PBDEs in worms collected from historically sludge-amended agricultural fields. In the current research, biota-soil accumulation factors (BSAFs) were appreciably higher (dependent upon dose) than those reported in these Swedish field studies. PBDE usage in Sweden has been much less intense than in North America. Increasing BSAFs with decreasing biosolids-amended soil burdens may indicate that PBDE constituents within these biosolid products may impact earthworms at relatively low levels in soil. The potential for a terrestrial arthropod, the house cricket ( Acheta domesticus) to take up PBDEs directly from consumer PUF was also evaluated in a laboratory bioassay. These insects frequent indoor spaces and discarded materials and hence may have increased access (and thus exposure) to PBDE-treated polymers. Cricket nymphs were reared in proximity to a commercially manufactured Penta-BDE-treated PUF. They accumulated SigmaPBDEs (47+85+99+100+153+154) up to 14,200 mug/kg lipid after 28 days. Non-depurated crickets ingested SigmaPBDE burdens up to 80,600 mug/kg lipid. Owing to the high PBDE content of the PUF (9% by weight) and the fact that much of it likely remained within the polymer matrix, cricket/PUF bioaccumulation factors (BAFs) were on the order of 10-4 to 10-3 for all PBDE congeners. to evaluate real-world biosolid-associated PBDE bioavailability in the soil-associated terrestrial environment, a food web bioaccumulation study was conducted within a Mid-Atlantic US agricultural soil ecosystem receiving long-term (>20 years) sludge amendments. Patterns of those with most intimate contact and reliance on the soil (e.g. earthworms) most closely reflected the soil/biosolid/commercial Penta-BDE fingerprint. PBDEs were BQL in the herbivorous grasshopper, in contrast to the closely related cricket, an omnivorous scavenger. Surprisingly, PBDEs were largely BQL in predaceous wolf spiders regardless of size or trophic level. Penta-BDE constituent biota-soil accumulation factors (BSAFs) ranged from 0.006 (crickets) to 1.2 (earthworms), while BDE-209 BSAFs ranged from 0.07 (earthworms) to 10.5 (millipedes). Lipid and TOC normalized PBDE burdens were strongly correlated for earthworms and ground beetles, perhaps indicative of attainment of steady state accumulation. In general, PBDE burdens decreased in the invertebrates with trophic level at the sludge-amended field. The pattern of carbon (delta13C) and nitrogen (delta 15N) stable isotopes in the taxa sampled suggests different trophic interactions at the non-sludge and sludge-applied fields. However, as only two sites were surveyed, a more exhaustive data set is needed in order to draw more definitive conclusions. Results of these studies provide unequivocal evidence that PBDEs accumulate in soils where biosolids are applied. They also demonstrate that PUF- and biosolid-associated PBDEs are bioavailable and are accumulated to varying degrees by ecologically diverse soil-associated invertebrates. as such, they may become available for uptake by higher order terrestrial consumers, including reptiles, mammals and birds. (Abstract shortened by UMI.).

Copper(II) complexes of Schiff bases can be used in the catalysis of hydrogen peroxide to create water and oxygen. The mechanism and the kinetics of this disproportionation reaction by a dimeric copper(II) complex [CuSALAD]2 are studied in this experiment, where SALAD refers to a Schiff Base ligand formed from salicyaldehyde and 1S,2S-D(+)-1-phenyl-2-amino-1,3-propanediol. By using cyclic voltammetry, the oxidation-reduction processes of a reaction may be monitored. The [CuSALAD]­2 is initially reacted with a base such as imidazole to form the catalytic species, and the ratio of the copper(II) complex to the imidazole was found to be 1:4, consistent with previous electron absorption (UV-Vis) spectroscopy experiments. The reduction and oxidation half waves of the copper(II) catalyst are followed via cyclic voltammetry to determine if the copper(II) center undergoes reduction to copper(I) during the hydrogen peroxide catalysis. It appears that while the major oxidation and reduction half wave potentials, E1/2=6.51x10-2V, are unchanged during the decomposition, an additional oxidation wave (E1/2=1.43x10-1V) is observed in the absence of oxygen, suggesting some portion of the copper is reduced. With this information, a mechanism was proposed having copper as a catalyst and creating an intermediate that would form the water and the elemental oxygen.

The goal of this research was the development of a method to extract pure (1,3/1,6)-β-glucans from Saccharomyces cerevisiae. These β-glucans are of pharmaceutical importance because an animal’s immune system can recognize glucan molecules, and these molecules can act as immunomodulators, essentially turning on the immune system. The problem in the past has been that previously published methods produce β-glucans with low side chain lengths and few branching occurrences. This issue was tackled by a multivariable approach that reduced extraction steps, initial sample size, and concentrations of reagents used. This method has been shown to produce greater yields of β-glucans while maintaining high purity. Analyses such as 1H-NMR and GC-MS have been used to confirm the content of the extracted glucans. Ideally, this research will generate interest for further β-glucan studies and ultimately be utilized pharmacologically with immunocompromised individuals.

abstract: Disease prevention and personalized treatment will be impacted by the continued integration of protein biomarkers into medical practice. While there are already numerous biomarkers used clinically, the detection of protein biomarkers among complex matrices remains a challenging problem. One very important strategy for improvements in clinical application of biomarkers is separation/preconcentration, impacting the reliability, efficiency and early detection. Electrophoretic exclusion can be used to separate, purify, and concentrate biomarkers. This counterflow gradient technique exploits hydrodynamic flow and electrophoretic forces to exclude, enrich, and separate analytes. The development of this technique has evolved onto an array-based microfluidic platform which offers a greater range of geometries/configurations for optimization and expanded capabilities and applications. Toward this end of expanded capabilities, fundamental studies of subtle changes to the entrance flow and electric field configurations are investigated. Three closely related microfluidic interfaces are modeled, fabricated and tested. A charged fluorescent dye is used as a sensitive and accurate probe to test the concentration variation at these interfaces. Models and experiments focus on visualizing the concentration profile in areas of high temporal dynamics, and show strong qualitative agreement, which suggests the theoretical assessment capabilities can be used to faithfully design novel and more efficient interfaces. Microfluidic electrophoretic separation technique can be combined with electron microscopy as a protein concentration/purification step aiding in sample preparation. The integrated system with grids embedded into the microdevice reduces the amount of time required for sample preparation to less than five minutes. Spatially separated and preconcentrated proteins are transferred directly from an upstream reservoir onto grids. Dilute concentration as low as 0.005 mg/mL can be manipulated to achieve meaningful results. Selective concentration of one protein from a mixture of two proteins is also demonstrated. Electrophoretic exclusion is also used for biomarker applications. Experiments using a single biomarker are conducted to assess the ability of the microdevice for enrichment in central reservoirs. A mixture of two protein biomarkers are performed to evaluate the proficiency of the device for separations capability. Moreover, a battery is able to power the microdevice, which facilitates the future application as a portable device. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2019

Mestrado em Química Analítica Ambiental / MSc in Environmental Analytical Chemistry

Petroleum is one of the most important natural resources, but can also be problematic to environmental and human health. Petroleum is comprised of thousands of compounds, including polycyclic aromatic hydrocarbons (PAHs) and heterocycles, some of which are toxic and/or carcinogenic. Traditional analytical methods for environmental monitoring of low-level PAHs are time-consuming labor-intensive, and often laboratory-bound. Efforts to achieve timely, sensitive, and accurate analysis of PAHs in the field have become a priority for environmental research and monitoring. Antibody-based biosensors are presently being developed for environmental analysis. Anti-PAH antibody molecules can be coupled with electronic transducers to provide new biosensor technology for the rapid determination and quantification of PAHs. Although PAHs are not immunogenic on their own, advances in immunology have provided the means to develop antibodies to PAHs. Thiophenes, a defined subset of aromatic heterocycles, were selected as the target molecules for antibody development. Characterization of a monoclonal antibody (mAb) to dibenzothiophene revealed specificity for 3 to 5-ring PAHs and heterocycles. Therefore, the goals of antibody development were focused on developing additional antibodies to 2-ring PAHs and to alkylated PAHs. Characterization of antibodies to these novel targets revealed unexpected insights into antibody induction and specificity: namely suitable hapten sizes for small hydrophobic molecule recognition should be larger than one benzene ring, derivatization of the hapten target in immunogen synthesis must preserve structural characteristics, the utility of heterologous assay formats can improve antibody inhibition, and high antibody titers can result in limited assay sensitivity. The anti-dibenzothiophene mAb 7B2.3 was employed, along with a fluorescence-based transducer, for the generation of a new biosensor for PAHs. The biosensor was utilized in a variety of different applications to determine dissolved PAH concentrations including: 1) sampling groundwater at a former wood-treatment (creosote) facility, 2) analyzing estuarine water during the dredging of PAH-contaminated sediments, revealing a plume of PAHs emanating from the dredge site, 3) frequent monitoring of phenanthrene (a 3-ring PAH) concentrations during a laboratory toxicological dosing study, and 4) monitoring PAH concentrations in stormwater runoff into both a retention pond and a river near a roadway. Overall, these applications demonstrated the utility of this biosensor for rapid analysis of PAHs in a variety of aqueous environments. The biosensor was operated on-site for both the estuarine and groundwater monitoring trials. The biosensor could process samples, produce quantitative measurements, and regenerate itself in approximately 10 minutes. Sample volumes of 400 mul could be used with little to no sample pretreatment. Most importantly, PAHs could be quantified down to 0.3 microg/l in the field using the sensor platform. These results were validated with conventional gas chromatography-mass spectrometry and high performance liquid chromatography analytical methods. This system shows great promise as a field instrument for the rapid monitoring of PAH pollution.