O presente trabalho realiza um estudo do desempenho aerodinâmico da turbina eólica de duas pás e 10 m de diâmetro da UAE Phase VI, testada pelo NREL no túnel de vento NASA Ames, através do uso de dinâmica dos fluidos computacional (CFD). Para tanto são apresentados conceitos fundamentais para análise da performance do aerogerador, a metodologia aplicada para a análise numérica e os resultados obtidos. O modelo geométrico da turbina foi inserido em ambiente computacional num domínio com as mesmas dimensões da seção de testes do túnel de vento. A esse domínio foi empregada uma malha de elementos tetraédricos. A modelagem numérica e as simulações foram efetuadas através do código comercial ANSYS FLUENT 13.0 e utilizaram as equações médias de Reynolds e modelos de turbulência k  SST e Spalart-Allmaras. A turbina simulada possui ângulo de giro (yaw) e de cone de 0°. Os casos simulados foram de turbina com ângulos de passo das pás de 0° e 3°, para velocidades de ar na entrada do domínio de 5 m/s, 7 m/s e 9 m/s. As simulações foram feitas em regime transiente utilizando o método de malha móvel. Dados provenientes da simulação numérica são comparados aos dados experimentais de empuxo, torque e potência, divulgados pelo laboratório. Os modelos de turbulência testados apresentaram boa concordância com os resultados experimentais de empuxo. O torque e a potência foram bem previstos para velocidades de entrada do domínio baixas, mas foram subdimensionados para velocidades mais altas. A separação da camada limite foi prevista por ambos os modelos. Na comparação com resultados obtidos com outros autores para o mesmo caso, o início de descolamento da camada limite se deu antes do previsto. A metodologia adotada nas simulações numéricas realizadas mostrou-se adequada e representativa nas análises desse estudo. / This study makes a CFD analysis of the aerodynamic performance of the NREL UAE Phase VI two-bladed wind turbine, which have been tested in the NASA Ames wind tunnel. Fundamental concepts on the evaluation of turbine performance, the applied methodology for the numerical analysis and the results are presented. A numerical model has been inserted in a computational environment that has the same dimensions as the real wind tunnel section, and a tetrahedral mesh has been created to fill this domain. Numerical modeling and the simulations have been performed using the ANSYS FLUENT 13.0 commercial code, making use of the RANS equations and the k  SST and Spalart-Allmaras turbulence models. The simulated turbine has 0 degrees of cone and yaw angle. Simulations were performed in unsteady state using the moving mesh technique. Results are compared to experimental data regarding to thrust, torque and power. The k  SST and Spalart-Allmaras turbulence models have shown good agreement with experimental values of thrust. Torque and power have been adequately predicted to lower free flow velocities, but have been underpredicted to higher velocities. Separation of the boundary layer has been adequately predicted by both models, but the beginning of the separation occurred earlier than expected in comparison with results of other authors to the same case. The methodology used in the numerical simulations proved to be adequate and representative in this study.

abstract: This dissertation addresses challenges pertaining to multi-junction (MJ) solar cells from material development to device design and characterization. Firstly, among the various methods to improve the energy conversion efficiency of MJ solar cells using, a novel approach proposed recently is to use II-VI (MgZnCd)(SeTe) and III-V (AlGaIn)(AsSb) semiconductors lattice-matched on GaSb or InAs substrates for current-matched subcells with minimal defect densities. CdSe/CdTe superlattices are proposed as a potential candidate for a subcell in the MJ solar cell designs using this material system, and therefore the material properties of the superlattices are studied. The high structural qualities of the superlattices are obtained from high resolution X-ray diffraction measurements and cross-sectional transmission electron microscopy images. The effective bandgap energies of the superlattices obtained from the photoluminescence (PL) measurements vary with the layer thicknesses, and are smaller than the bandgap energies of either the constituent material. Furthermore, The PL peak position measured at the steady state exhibits a blue shift that increases with the excess carrier concentration. These results confirm a strong type-II band edge alignment between CdSe and CdTe. The valence band offset between unstrained CdSe and CdTe is determined as 0.63 eV±0.06 eV by fitting the measured PL peak positions using the Kronig-Penney model. The blue shift in PL peak position is found to be primarily caused by the band bending effect based on self-consistent solutions of the Schrödinger and Poisson equations. Secondly, the design of the contact grid layout is studied to maximize the power output and energy conversion efficiency for concentrator solar cells. Because the conventional minimum power loss method used for the contact design is not accurate in determining the series resistance loss, a method of using a distributed series resistance model to maximize the power output is proposed for the contact design. It is found that the junction recombination loss in addition to the series resistance loss and shadowing loss can significantly affect the contact layout. The optimal finger spacing and maximum efficiency calculated by the two methods are close, and the differences are dependent on the series resistance and saturation currents of solar cells. Lastly, the accurate measurements of external quantum efficiency (EQE) are important for the design and development of MJ solar cells. However, the electrical and optical couplings between the subcells have caused EQE measurement artifacts. In order to interpret the measurement artifacts, DC and small signal models are built for the bias condition and the scan of chopped monochromatic light in the EQE measurements. Characterization methods are developed for the device parameters used in the models. The EQE measurement artifacts are found to be caused by the shunt and luminescence coupling effects, and can be minimized using proper voltage and light biases. Novel measurement methods using a pulse voltage bias or a pulse light bias are invented to eliminate the EQE measurement artifacts. These measurement methods are nondestructive and easy to implement. The pulse voltage bias or pulse light bias is superimposed on the conventional DC voltage and light biases, in order to control the operating points of the subcells and counterbalance the effects of shunt and luminescence coupling. The methods are demonstrated for the first time to effectively eliminate the measurement artifacts. / Dissertation/Thesis / Ph.D. Electrical Engineering 2012

O experimento Unsteady Aerodynamics Experiment Phase VI, realizado no ano de 2000 pelo Laboratório Nacional norte-americano para as Energias Renováveis (NREL) no túnel de vento Ames da NASA, foi reproduzido numericamente neste trabalho. O objetivo é o estudo das características da esteira aerodinâmica produzida pela turbina eólica de duas pás e 10 metros de diâmetro, operando à velocidade de rotação constante de 72 RPM, sujeita a uma velocidade de corrente livre do vento uniforme de 9 m/s, em um túnel de vento cuja seção de testes mede 36,6 m de largura por 24,4 m de altura e o comprimento mede 170 m. Para isso, foi utilizado o programa comercial ANSYS FLUENT versão 13.0, baseado no Método dos Volumes Finitos para a solução numérica das Equações de Navier-Stokes em regime transiente em conjunto com a Simulação de Grandes Escalas (SGE) para resolver a turbulência. As geometrias de todos os componentes da máquina foram criadas em software CAD. Um domínio móvel em forma de disco, contendo as pás do rotor e o hub da máquina, foi criado separadamente, e posteriormente inserido no domínio principal, estático, usando a ferramenta Moving Mesh disponível no software FLUENT. Ambos os domínios foram preenchidos por malhas compostas por tetraedros. Dados provenientes das simulações numéricas foram comparados aos dados experimentais de velocidade fornecidos por dois anemômetros sônicos instalados 5,8 m à jusante do rotor, ao que foi verificada boa concordância, com diferenças da ordem de 1% para o anemômetro 1 e 6% para o anemômetro 2. Resultados de velocidade na linha de centro do túnel e perfis de velocidade à jusante foram comparados com recente estudo numérico, e revelam diferenças importantes entre dados obtidos pela SGE, principalmente no que se refere à detecção de picos e flutuações relacionados às escalas turbulentas, e dados obtidos através da modelagem clássica da turbulência, RANS. As perturbações ultrapassaram a marca dos 10 diâmetros à jusante e atingiram o final do domínio localizado a 15 diâmetros. A esteira não apresentou simetria axial, e o ponto de maior redução na velocidade do escoamento foi detectado fora da linha de centro do rotor. / The Unsteady Aerodynamics Experiment Phase VI, which has been carried out in 2000 by the US National Renewable Energy Laboratory (NREL) at the NASA Ames wind tunnel, has been numerically reproduced. The purpose of this work is to study the characteristics of the wind wake produced by the 10 meter two bladed wind turbine, operating at a constant rotational speed of 72 RPM, subject to a free stream wind velocity of 9 m/s, inside a wind tunnel in which dimensions are 36.6 m in width, 24.4 m in height and length of 170 m. To achieve that, the ANSYS FLUENT version 13.0 commercial code, based in the Finite Volume Method to numerically solve the Navier-Stokes equations in transient state, has been used, together with the Large Eddy Simulation (LES) to characterize the turbulence. Geometries of all the machine components have been created in CAD software. A disc shaped moving domain, containing the blades and hub, has been created separately, and later inserted into the main, static domain, using the Moving Mesh tool available in the software. Both domains have been filled with meshes composed by tetrahedra. Data collected at the numerical simulations have been compared to experimental wind speed data provided by two sonic anemometers installed 5.8 m downstream from the rotor, for which a good agreement has been found, with differences of approximately 1% to the anemometer 1 and 6% to the anemometer 2. Results of wind velocity at the tunnel centerline and velocity profiles downstream have been compared with recent numerical study, and show important differences between data obtained by LES, especially with regard to the detection of peaks and fluctuations related to the turbulent scales, and data obtained by the classic turbulence modeling, RANS. Disturbances have passed the 10 diameter mark and reached the end at the domain located at 15 diameters. The wake did not show axial symmetry and the point of maximum reduction in the flow speed was detected outside the rotor centerline.

O presente trabalho realiza um estudo do desempenho aerodinâmico da turbina eólica de duas pás e 10 m de diâmetro da UAE Phase VI, testada pelo NREL no túnel de vento NASA Ames, através do uso de dinâmica dos fluidos computacional (CFD). Para tanto são apresentados conceitos fundamentais para análise da performance do aerogerador, a metodologia aplicada para a análise numérica e os resultados obtidos. O modelo geométrico da turbina foi inserido em ambiente computacional num domínio com as mesmas dimensões da seção de testes do túnel de vento. A esse domínio foi empregada uma malha de elementos tetraédricos. A modelagem numérica e as simulações foram efetuadas através do código comercial ANSYS FLUENT 13.0 e utilizaram as equações médias de Reynolds e modelos de turbulência k  SST e Spalart-Allmaras. A turbina simulada possui ângulo de giro (yaw) e de cone de 0°. Os casos simulados foram de turbina com ângulos de passo das pás de 0° e 3°, para velocidades de ar na entrada do domínio de 5 m/s, 7 m/s e 9 m/s. As simulações foram feitas em regime transiente utilizando o método de malha móvel. Dados provenientes da simulação numérica são comparados aos dados experimentais de empuxo, torque e potência, divulgados pelo laboratório. Os modelos de turbulência testados apresentaram boa concordância com os resultados experimentais de empuxo. O torque e a potência foram bem previstos para velocidades de entrada do domínio baixas, mas foram subdimensionados para velocidades mais altas. A separação da camada limite foi prevista por ambos os modelos. Na comparação com resultados obtidos com outros autores para o mesmo caso, o início de descolamento da camada limite se deu antes do previsto. A metodologia adotada nas simulações numéricas realizadas mostrou-se adequada e representativa nas análises desse estudo. / This study makes a CFD analysis of the aerodynamic performance of the NREL UAE Phase VI two-bladed wind turbine, which have been tested in the NASA Ames wind tunnel. Fundamental concepts on the evaluation of turbine performance, the applied methodology for the numerical analysis and the results are presented. A numerical model has been inserted in a computational environment that has the same dimensions as the real wind tunnel section, and a tetrahedral mesh has been created to fill this domain. Numerical modeling and the simulations have been performed using the ANSYS FLUENT 13.0 commercial code, making use of the RANS equations and the k  SST and Spalart-Allmaras turbulence models. The simulated turbine has 0 degrees of cone and yaw angle. Simulations were performed in unsteady state using the moving mesh technique. Results are compared to experimental data regarding to thrust, torque and power. The k  SST and Spalart-Allmaras turbulence models have shown good agreement with experimental values of thrust. Torque and power have been adequately predicted to lower free flow velocities, but have been underpredicted to higher velocities. Separation of the boundary layer has been adequately predicted by both models, but the beginning of the separation occurred earlier than expected in comparison with results of other authors to the same case. The methodology used in the numerical simulations proved to be adequate and representative in this study.

The growth of anthropogenic actions, especially industrial development and urbanization, has increased the release of heavy metals in the environment, including hexavalent chromium, Cr (VI), requiring, as a matter of urgency, new processes for pollutants removal, among which are the adsorption processes, which are the focus of this work. Biosorption is an efficient, economical, high selectivity and low energy consumption technique. The main objective of this work was the production of a biosorbent from the crop residues of Cocos nucifera, enhancing it with superparamagnetic properties, as a viable technical and economical alternative, able to adsorb hexavalent chromium ions, Cr (VI), applicable to the treatment of industrial wastewater, expanding pollution control strategies and minimizing environmental impacts. Thus, low concentration coprecipitation routes for the synthesis of nanoparticle (NPs) were proposed, conveying magnetic property to the Cocos nucifera biomass. During the biosorption of hexavalent chromium ions, Cr (VI), the saturation conditions (equilibrium) and the kinetic parameters were evaluated to determine the maximum removal capacity and equilibrium time for the biosorption, besides the optimum conditions for pH, initial concentration, biosorbent content, particle size (grain size), stirring velocity and temperature, providing the fitting of equilibrium models and kinetic constants determination. The biosorbents were characterized by scanning electron microscopy techniques with dispersive energy spectroscopy (SEM/EDS), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (EDX), X-ray fluorescence with dispersive energy (FR-X/WD), thermogravimetric analysis (TGA), magnetization measurements, zero load point analysis (pCZ), and specific surface analysis through the Brunauer, Emmet and Teller (BET) method. The leachate effluent obtained in the production of the magnetized fibers was characterized through the parameters biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC) and pH. The characterization of biosorbents and the determination of kinetic and equilibrium parameters provided the main mechanisms of the biosorption process, giving arise to a possible application on an industrial scale, helping to solve serious environmental problems. / O crescimento das atividades antrópicas, sobretudo o desenvolvimento industrial e o crescimento das cidades têm como consequência o aumento do descarte de metais pesados no ambiente com destaque para o cromo hexavalente, Cr(VI), demandando, urgentemente, novos processos para remoção destes poluentes, dentre os quais os processos adsortivos, que são o foco do presente trabalho. A biossorção tem se destacado como uma técnica eficaz, econômica, de alta seletividade e baixo consumo energético. O objetivo principal desse trabalho é a produção de um biossorvente a partir de rejeitos agrícolas de fibra de Cocos nucifera com propriedades superparamagnética, capaz de adsorver íons de cromo hexavalente, Cr(VI), facilmente aplicável as indústrias, como uma alternativa técnica e econômica viável, ampliando as estratégias de controle de poluentes e minimizando os impactos ambientais. Com essa finalidade foram propostas rotas de síntese de coprecipitação de nanoparticulas (NPs) de magnetita, em baixas concentrações, promovendo propriedade magnética à biomassa das fibras do Cocos nucifera. No processo de biossorção dos íons cromo hexavalente, Cr(VI), foram avaliadas as condições de saturação (equilíbrio) e os parâmetros cinéticos para determinar a capacidade máxima de remoção e o tempo de equilíbrio da biossorção, além das condições ótimas de pH, concentração inicial e carga dos biossorventes, tamanho das partículas (granulometria), velocidade de agitação e temperatura, definindo os modelos de equilíbrio e as constantes cinéticas. Os biossorventes foram caracterizados pelas técnicas de microscopia eletrônica de varredura com espectroscopia de energia dispersiva (MEV/EDS), espectrometria de infravermelho por transformada de Fourier (FT-IR), difratometria de raios-X (EDX), fluorescência de raios-X por energia dispersiva (FR-X/WD), análise termogravimétrica (TGA), medidas de magnetização, análise do ponto de carga zero (pCZ) e análise superficial especifica pelo método de Brunauer, Emmet e Teller (B.E.T). O lixiviado, efluente obtido na produção das fibras magnetizadas, foi caracterizado pelas determinações da demanda bioquímica de oxigênio (DBO), demanda química de oxigênio (DQO), carbono orgânico total (COT) e pH. Como resultado da caracterização dos biossorventes e dos cálculos dos parâmetros cinéticos e de equilíbrio, foi possível sugerir os principais mecanismos do processo de biossorção, facilitando uma possível aplicação em escala industrial, remediando sérios problemas ambientais.

Submitted by Maria Dulce (mdulce@ndc.uff.br) on 2013-12-13T18:47:09Z No. of bitstreams: 2 Braga, Nilza-Disser-2013.pdf: 18016395 bytes, checksum: 6d01df9ddbf40cb8ec4e3c9ab3b057a2 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2013-12-13T18:47:09Z (GMT). No. of bitstreams: 2 Braga, Nilza-Disser-2013.pdf: 18016395 bytes, checksum: 6d01df9ddbf40cb8ec4e3c9ab3b057a2 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013 / A presente dissertação discute a trajetória mercantil e honorífica de Elias Antonio Lopes, um dos maiores negociantes que atuou na praça mercantil do Rio de Janeiro em fins do século XVIII e nos primeiros quinze anos do século XIX. Ele emigrou da cidade do Porto para o Rio de Janeiro em aproximadamente 1770, para tentar a sorte nos ofícios mercantis. Ele concentrou em suas mãos uma grande fortuna, advinda de diferentes ramos mercantis, como o tráfico negreiro, arrecadação de contratos reais, comércio interno e externo. O negociante angariou variadas mercês, fundamentais em sua mobilidade social ascendente, em fins do século XVIII e principalmente após a vinda da Corte joanina em 1808. Isso aconteceu, após o negociante ter doado sua chácara em São Cristóvão e futura Quinta da Boa Vista para servir de residência da família real portuguesa. Neste sentido, discutiremos que o ideal aristocrático do Antigo Regime português esteve presente no início do século XIX quando os negociantes procuraram status social ao serem agraciados com mercês em retribuição aos serviços prestados a Dom João. Elias Antonio Lopes faleceu no ano de 1815 deixando uma grande herança, disputada entre seus herdeiros e a Coroa portuguesa pelo fato de ele não ter deixado testamento. Portanto, este estudo perpassa, desde a emigração de Lopes para o Rio de Janeiro, até sua trajetória mercantil e honorífica, encerrando-se com seu falecimento e disputa por sua herança. / In this dissertation, a detailed discussion of the mercantile and honorific route of Elias Antonio Lopes is explored. Elias was the greatest dealer, who played a significant role in the Rio de Janeiro imperial market by the ends of XVIII century and the first years of XIX century. He emigrated from the Porto city, Portugal, to the Rio de Janeiro, probably in the year of 1770 in order to get a chance in the market place of Rio de Janeiro. He got a great fortune from different facets of the mercantile area such as slave trade, the getting of royal contracts, as well as getting from internal and foreign markets. As a trader, he could assemble a great deal of benefices (mercês), which were fundamental in order to get social nobility in the XVIII, when the Portuguese royals arrived in 1808. All these took place after the donating of his own farmland in São Cristóvão, neighbourhood, the future Portuguese royal house. In this sense, it is discussed here that the aristocratic ideal in that time was commonplace in the beginnings of the XIX century, when the traders used to urge in getting social status by acquisition of titles through services provided to Dom João. Elias Antonio Lopes passed away in the year of the 1815 leaving a great inheritance, eagerly rivaled by his heirs and the Portuguese Crown, as he did not leave any testament. Therefore, this study is a large passing through of his route since his emigration to Rio de Janeiro, his honorific dealings in the mercantile marketing, ending up with his suddenly death and the eagerly rivalry of his properties.

The thesis subject is based on a report published by Amnesty International with the title ”Dangerously Disproportionate: The ever expanding security state in Europe”. The report accuses EU states of an ongoing securitization due to terrorism and the migration crises that has led to the discrimination of especially Muslims and foreign nationals. With the report as starting point this paper aims to investigate how inclusion and exclusion is made in the security discourse of the Swedish government and parliament between 2015 and 2017. The time frame is chosen based on Amnesty’s assessment of a shift in paradigm with starting point after the terror attacks in Paris 2015. As theory and method this paper makes use of Laclau & Mouffe´s discourse theory to perform a discourse analyses. Previous research of scientists and theorists is used to operationalize both inclusion and exclusion. The results of the study show that inclusion and exclusion in the discourse is made by talking about the migration crises, unaccompanied refugee children, antisemitism, terrorists, and those who need protection; us. One of the most prominent conclusions related to the analysis is that the figure of the migrant is excluded by means of framing it as a security problem leading to the possible system collapse of prominent welfare and social functions in society. / Uppsatsens ämnesval bygger på Amnesty Internationals rapport med titeln ” Dangerously Disproportionate: The ever expanding security state in Europe” som anklagar de europeiska länderna för en säkerhetiseringsprocess på grund av terrorism och migrationskrisen, vilket huvudsakligen drabbar migranter och människor av muslimsk tro. Med rapporten som utgångspunkt valdes en undersökning av inkludering och exkludering i den svenska regeringens och riksdagens säkerhetsdiskurs med målet att söka efter hur inkludering och exkludering ”görs” i relation till migrations- och terrorkrisen mellan åren 2015 och 2017. Tidsramen valdes på grund av att Amnesty Internationals rapport pekade ut ett paradigmskifte efter terrordådet i Paris 2015. Som teori och analysmetod används Laclau & Mouffes diskursteori som bygger på premissen att verkligheten är socialt konstruerad. Som operationaliseringar av begreppen inkludering och exkludering användes tidigare forskning. Resultatet av undersökningen visade att inkludering och exkludering görs i diskursen när det talas om migrationskrisen, ensamkommande, antisemitism, terrorister och den gruppen som ska skyddas. En av de mest tydliga slutsatser som dras från analysen är att migranten framställs som ett säkerhetsproblem som är ansvarigt för den hotande systemkollapsen av välfärden och viktiga samhällsfunktioner i Sverige, samt att det är en tydlig förändring i förhållande till en tidigare mer generös och inkluderande hållning mot migranten.

The master thesis deals with failed studies at universities in the Czech Republic. The first part is focused on literary research, on explanation of theoretical terms and on statistical methods, which are subsequently applied in the analytical part. These are decision trees and logistic regression that helped to determine the influence of factors on studies without graduation. The aim of this master thesis is to find significant factors, to compile a profile of failed students and to suggest the measures which could reduce their elimination from tertiary education.

La chirurgie guidée par l’imagerie de fluorescence est une technique prometteuse mais limitée par la faible profondeur de pénétration (inférieure au millimètre dans le visible) à cause de l’absorption et de la diffusion par les tissus. Elle est plus élevée dans la gamme du proche infrarouge (700-1000 nm) mais reste limitée à quelques centimètres. L’imagerie par résonance magnétique (IRM) permet d’obtenir des images sur corps entier mais ne peut être utilisée pour le suivi peropératoire. Le développement de sondes bimodales, fluorescentes et magnétiques, permet de coupler les avantages des deux techniques.Nous avons choisi de développer des sondes basées sur des nanocristaux fluorescents de CuIn(S,Se)2 car ils présentent une longueur d’onde d’émission modulable sur toute la gamme du proche infrarouge ainsi que des rendements quantiques, sections efficace d’absorption et photostabilités élevés. La croissance d’une coque épaisse de ZnS permet d’augmenter le rendement quantique qui peut atteindre 60 % dans les solvants organiques. L’incorporation d'ions Mn2+ dans la coque de nos objets permet de leur conférer un caractère paramagnétique. Les propriétés optiques et structurales ont été étudiées par spectroscopie (fluorescence et absorbance), RPE, DRX, MET/METHR et analyse élémentaire. Nos sondes sont transférées en milieu aqueux par un échange de ligands qui ne modifie pas leurs propriétés. Des mesures de relaxivités longitudinales ont permis de confirmer leur potentiel comme agent de contraste pour l’IRM pondérée en T1 et nous avons apporté une preuve de principe de l’utilisation de nos sondes in vivo en marquant des ganglions lymphatiques chez la souris. / Fluorescence imaging is a promising technique for image-guided surgery. Because of diffusion and absorption of light by tissues, the low penetration depth (less than a millimeter) in the visible spectral range, which can reach a few centimeters in the near infrared (NIR) spectral range (700-1000 nm), limits its use. To overcome this limitation, fluorescence imgaging can be coupled with magnetic resonance imaging (MRI) which provides whole body images but cannot be used for intraoperative monitoring. Thus, the development of bimodal fluorescent and magnetic (for MRI) probes offers the opportunity to combine advantages from both imaging modalities.In this regard, we chose to use CuIn(S,Se)2 fluorescent semiconductor nanocrystals(or quantum dots) as a platform for the development of our probes. They display a size-tunable emission wavelength over the NIR spectral range and high quantum yield, absorption cross section and photostability. The growth of a thick shell of ZnS on these nanoparticles can increase the quantum yield up to 60 % in organic media.The incorporation of Mn2+ ions in the shell gives our probes a paramagnetic behavior. The influence of doping level on structural and optical properties is investigated using fluorescence and absorbance spectroscopy, EPR, XRD, TEM/HRTEM and elemental analysis. Our probes are solubilized in water through a ligand exchange and their properties remain stable in water. Longitudinal relaxivity measurements show that these probes can be used as MRI T1 contrast agents. As a proof-of-principle, we demonstrate that these probes can be used for the detection of lymph nodes in vivo.

Submitted by Adriana Martinez (amartinez@unoeste.br) on 2017-08-31T20:12:04Z No. of bitstreams: 1 João Marcelo Martins Coluna.pdf: 316916 bytes, checksum: e3ff1f0c4795f8a26f2d99c916a84f41 (MD5) / Made available in DSpace on 2017-08-31T20:12:04Z (GMT). No. of bitstreams: 1 João Marcelo Martins Coluna.pdf: 316916 bytes, checksum: e3ff1f0c4795f8a26f2d99c916a84f41 (MD5) Previous issue date: 2014-03-24 / The aim of this study was to evaluate the effect of probiotics on the toxicity of increasing doses of potassium dichromate on the reproductive tract and adrenal glands of rats . Material and Methods: During a trial period of 90 days , we used 80 Wistar rats were divided randomly into 8 groups of 10 animals : GC (control ) , G1 (12 mg.kg - 1 K2Cr2O7 ) ; G24 ( 24 mg.kg - 1 K2Cr2O7 ) ; G36 ( 36 mg.kg - 1 K2Cr2O7 ) ; GP Control ( 0.2% probiotic ); G12P ( 12 mg.kg - 1 K2Cr2O7 + Probiotic 0.2 % ) ; G24P ( 24 mg.kg - 1 K2Cr2O7 + Probiotic 0.2 % ) ; G36P ( 36 mg.kg - 1 K2Cr2O7 Probiotic + 0.2% ) . Subsequently , weighing and histological evaluation of the reproductive organs and adrenal glands was performed , and plasma testosterone dosage . Results: Testes were heavier in group 7 There were statistical differences between the weights of the seminal vesicles only in groups 2:07 Histologically observed development of atypical hyperplasia and squamous metaplasia in the testes and seminal vesicles and degeneration of the germinal epithelium and tubular contraction testes despite the use of probiotics. Conclusion : The use of probiotics has not protected the epithelium of the reproductive system in this study . / O objetivo deste estudo foi avaliar o efeito do probiótico sobre a toxicidade de doses crescentes de dicromato de potássio sobre o trato reprodutivo e glândulas adrenais de ratos Wistar. Material e Métodos: Durante um período experimental de 90 dia, utilizou-se 80 ratos Wistar distribuídos aleatoriamente em 8 grupos de 10 animais: GC (controle), G12 (12 mg.kg-1 K2Cr2O7); G24 (24 mg.kg-1 K2Cr2O7); G36 (36 mg.kg-1 K2Cr2O7); GP (Controle, 0,2% probiótico); G12P (12 mg.kg-1 K2Cr2O7 + 0,2% Probiótico); G24P (24 mg.kg-1 K2Cr2O7 + 0,2% Probiótico); G36P (36 mg.kg-1 K2Cr2O7 + 0,2% Probiótico). Posteriormente foi realizada, pesagem e avaliação histológica dos órgãos reprodutivos e das glândulas adrenais, bem como dosagem de testosterona plasmática. Resultados: Os testículos pesaram mais no grupo 7. Houve diferença estatística entre os pesos das vesículas seminais somente nos grupos 2 e 7. Histologicamente observou-se desenvolvimento de hiperplasia atípica e metaplasia escamosa nos testículos e vesículas seminais e degeneração do epitélio germinativo e contração tubular nos testículos apesar do uso de probióticos. Conclusão: O uso de probiótico não protegeu o epitélio do sistema reprodutivo nesse estudo.