Long-range effects on optical absorption in quasiperiodic lattices

We consider exciton optical absorption in quasiperiodic lattices, focusing our attention on the Fibonacci case as a typical example. The absorption spectrum is evaluated by solving numerically the equation of motion of the Frenkel-exciton problem on the lattice, in which on-site energies take on two values according to the Fibonacci sequence. We find that the quasiperiodic order causes the occurrence of well-defined characteristic features in the absorption spectra. We also develop an analytical method that relates satellite lines with the Fourier pattern of the lattice. Our predictions can be used to determine experimentally the long-range quasiperiodic order from optical measurements.

Estudo da topologia de motores de fluxo axial de excitação híbrida com foco na utilização em tração elétrica.

Os motores de corrente contínua convencionais são muito bem conhecidos pela sua robustez e pelo seu alto nível de controlabilidade, alem do fato de possibilitarem a operação na região de enfraquecimento de campo (modo motor), quando esta situação se fizer necessária. Por estas características, as máquinas de corrente contínua ainda são empregadas nos dias atuais em nichos específicos de utilização. Não obstante, a máquina c.c. apresenta algumas desvantagens, principalmente a intensiva e dispendiosa manutenção eletromecânica necessária para sua operação. Como opção de sanar este problema, surgiram na década de 60, as máquinas elétricas de corrente contínua sem escovas (brushless) com excitação por ímãs permanentes de fluxo trapezoidal. O problema destas máquinas se deve justamente a impossibilidade da variação de fluxo de excitação uma vez que são produzidos puramente pelos ímãs. Sendo assim, este trabalho tem como propósito, o estudo de topologias diferenciadas da máquina elétrica, através de um circuito magnético não convencional para aplicação e utilização em sistemas de tração elétrica para operação na região de enfraquecimento de campo através da variação do fluxo resultante no entreferro. Como objeto de estudo, foi focada a topologia de fluxo axial com excitação híbrida, ou seja, dupla excitação (excitação a ímãs permanentes e excitação elétrica). Para o projeto da topologia proposta, nesta tese, adicionalmente ao método analítico, foram realizadas simulações computacionais para a comparação e refinamento dos resultados das grandezas eletromagnéticas da máquina.

Exposição a substâncias organocloradas em São Paulo: níveis séricos em doadores de sangue e fatores associados

A utilização de pesticidas organoclorados é motivo de preocupação das entidades ligadas à área de saúde em todo o mundo. Apesar de as formas de contaminação serem bem conhecidas, não há um controle eficaz na fiscalização do seu uso no Brasil. Sabe-se que altos níveis séricos destes compostos nos organismos de seres humanos e animais acarretam sérios problemas de saúde. Tendo em vista essa realidade, foi realizado, em 2009, o Projeto Piloto do I Inquérito Nacional de Populações Expostas a Substâncias Químicas, cujo subprojeto \"doadores de sangue\" teve como objetivo mensurar as concentrações de substâncias químicas no sangue de 547 residentes da região metropolitana de São Paulo, dentre elas os pesticidas organoclorados. Este trabalho teve como objetivos avaliar as concentrações dos pesticidas hexaclorobenzeno (HCB), alfa-HCH, ?-HCH, beta-HCH, beta-HCH, heptacloro, heptacloro epóxido, dieldrin, mirex, o,p\'-DDT, p,p\'-DDT, o,p\'-DDE, p,p\'-DDE, o,p\'-DDD e p,p\'-DDD nesta população e compará-las com as encontradas em outros países e determinar fatores associados aos níveis mais elevados destas substâncias. O método analítico utilizado foi de cromatografia a gás. Os resultados deste estudo indicam que a população adulta de São Paulo não está exposta a níveis preocupantes de pesticidas organoclorados, pois dentre os compostos analisados, apenas o beta-HCH e o p,p\'-DDE tiveram um número significante de amostras acima do limite de quantificação, 10,7% e 31,2% das amostras respectivamente. Quando utilizada a metade do limite de quantificação para substituir os valores abaixo do limite de quantificação do método, o valor médio encontrado para o beta-HCH foi de 0,028 ug/dL e para o p,p\'-DDE foi de 0,045 ug/dL. Este estudo propôs dois modelos multivariados para explicar os fatores associados aos compostos beta-HCH e p,p\'-DDE no sangue dos doadores. Segundo o modelo de Regressão Logística Ordinal Multivariado, os fatores associados a níveis mais altos de beta-HCH foram ter idade entre 26 e 45 anos e ser do sexo feminino. Para o p,p\'-DDE os fatores associados a níveis mais altos foram ter idade entre 26 e 45 anos, ser do sexo feminino e ter trabalhado com pesticidas, enquanto receber renda mensal de 3 a 5 salários mínimos e consumir derivados de origem animal uma ou mais vezes por semana foram associados a níveis mais baixos de p,p\'-DDE. Segundo o modelo de Regressão Linear Múltipla, os fatores associados a níveis mais altos de beta-HCH foram o sexo feminino, ter contato prévio com pesticidas na região agrícola, ter trabalhado com pesticidas em campanhas de saúde pública, ter trabalhado em empresas de capacitores ou transformadores, ter trabalhado em indústrias de solventes clorados, ter renda mensal de 3 a 5 salários mínimos, consumo de carnes uma ou duas vezes por semana e consumo de frutos do mar uma ou duas vezes por semana, enquanto consumo frequente de cerveja e ter renda mensal de 1 a 3 salários mínimos foram associado a níveis menores de beta-HCH. Já para o p,p\'-DDE, os fatores associados a níveis mais elevados foram ser do sexo feminino, ser não branco, ter trabalhado com pesticidas e consumir água de fontes que não sejam minerais ou de rede, enquanto o consumo frequente de bebidas alcoólicas foi associado a níveis mais baixos de p,p\'-DDE

Screen-printed electrode-based electrochemical detector coupled with in-situ ionic-liquid-assisted dispersive liquid–liquid microextraction for determination of 2,4,6-trinitrotoluene

A novel method is reported, whereby screen-printed electrodes (SPELs) are combined with dispersive liquid–liquid microextraction. In-situ ionic liquid (IL) formation was used as an extractant phase in the microextraction technique and proved to be a simple, fast and inexpensive analytical method. This approach uses miniaturized systems both in sample preparation and in the detection stage, helping to develop environmentally friendly analytical methods and portable devices to enable rapid and onsite measurement. The microextraction method is based on a simple metathesis reaction, in which a water-immiscible IL (1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, [Hmim][NTf2]) is formed from a water-miscible IL (1-hexyl-3-methylimidazolium chloride, [Hmim][Cl]) and an ion-exchange reagent (lithium bis[(trifluoromethyl)sulfonyl]imide, LiNTf2) in sample solutions. The explosive 2,4,6-trinitrotoluene (TNT) was used as a model analyte to develop the method. The electrochemical behavior of TNT in [Hmim][NTf2] has been studied in SPELs. The extraction method was first optimized by use of a two-step multivariate optimization strategy, using Plackett–Burman and central composite designs. The method was then evaluated under optimum conditions and a good level of linearity was obtained, with a correlation coefficient of 0.9990. Limits of detection and quantification were 7 μg L−1 and 9 μg L−1, respectively. The repeatability of the proposed method was evaluated at two different spiking levels (20 and 50 μg L−1), and coefficients of variation of 7 % and 5 % (n = 5) were obtained. Tap water and industrial wastewater were selected as real-world water samples to assess the applicability of the method.

Tungsten coil atomic emission spectrometry combined with dispersive liquid–liquid microextraction: A synergistic association for chromium determination in water samples

A novel and environment friendly analytical method is reported for total chromium determination and chromium speciation in water samples, whereby tungsten coil atomic emission spectrometry (WCAES) is combined with in situ ionic liquid formation dispersive liquid–liquid microextraction (in situ IL-DLLME). A two stage multivariate optimization approach has been developed employing a Plackett–Burman design for screening and selection of the significant factor involved in the in situ IL-DLLME procedure, which was later optimized by means of a circumscribed central composite design. The optimum conditions were complexant concentration: 0.5% (or 0.1%); complexant type: DDTC; IL anion: View the MathML sourcePF6−; [Hmim][Cl] IL amount: 60 mg; ionic strength: 0% NaCl; pH: 5 (or 2); centrifugation time: 10 min; and centrifugation speed: 1000 rpm. Under the optimized experimental conditions the method was evaluated and proper linearity was obtained with a correlation coefficient of 0.991 (5 calibration standards). Limits of detection and quantification for both chromium species were 3 and 10 µg L−1, respectively. This is a 233-fold improvement when compared with chromium determination by WCAES without using preconcentration. The repeatability of the proposed method was evaluated at two different spiking levels (10 and 50 µg L−1) obtaining coefficients of variation of 11.4% and 3.6% (n=3), respectively. A certified reference material (SRM-1643e NIST) was analyzed in order to determine the accuracy of the method for total chromium determination and 112.3% and 2.5 µg L−1 were the recovery (trueness) and standard deviation values, respectively. Tap, bottled mineral and natural mineral water samples were analyzed at 60 µg L−1 spiking level of total Cr content at two Cr(VI)/Cr(III) ratios, and relative recovery values ranged between 88% and 112% showing that the matrix has a negligible effect. To our knowledge, this is the first time that combines in situ IL-DLLME and WCAES.

Développement d’une lentille cornéenne médicamentée

L’utilisation de lentilles cornéennes peut servir à améliorer le profil d’administration d’un principe actif dans les yeux. Avec une efficacité d’administration de 5% par l’utilisation de gouttes, on comprend rapidement que l’administration oculaire doit être améliorée. Cette faible administration a donné naissance à plusieurs tentatives visant à fabriquer des lentilles cornéennes médicamentées. Cependant, à cause de multiples raisons, aucune de ces tentatives n’a actuellement été mise sur le marché. Nous proposons dans cette étude, une possible amélioration des systèmes établis par le développement d’une lentille cornéenne à base de 2-(hydroxyéthyle)méthacrylate (HEMA), dans laquelle des microgels, à base de poly N-isopropylacrylamide (pNIPAM) thermosensible encapsulant un principe actif, seront incorporé. Nous avons donc débuté par développer une méthode analytique sensible par HPCL-MS/MS capable de quantifier plusieurs molécules à la fois. La méthode résultante a été validée selon les différents critères de la FDA et l’ICH en démontrant des limites de quantifications et de détections suffisamment basses, autant dans des fluides simulés que dans les tissus d’yeux de lapins. La méthode a été validée pour sept médicaments ophtalmiques : Pilocarpine, lidocaïne, proparacaïne, atropine, acétonide de triamcinolone, timolol et prednisolone. Nous avons ensuite fait la synthèse des microgels chargés négativement à base de NIPAM et d’acide méthacrylique (MAA). Nous avons encapsulé une molécule modèle dans des particules ayant une taille entre 200 et 600 nm dépendant de la composition ainsi qu’un potentiel zêta variant en fonction de la température. L’encapsulation de la rhodamine 6G (R6G) dans les microgels a été possible jusqu’à un chargement (DL%) de 38%. L’utilisation des isothermes de Langmuir a permis de montrer que l’encapsulation était principalement le résultat d’interactions électrostatiques entre les MAA et la R6G. Des cinétiques de libérations ont été effectuées à partir d’hydrogels d’acrylamide chargés en microgels encapsulant la R6G. Il a été trouvé que la libération des hydrogels chargés en microgels s’effectuait majoritairement selon l’affinité au microgel et sur une période d’environ 4-24 heures. La libération à partir de ces systèmes a été comparée à des formules d’hydrogels contenant des liposomes ou des nanogels de chitosan. Ces trois derniers (liposomes, microgels et nanogels) ont présenté des résultats prometteurs pour différentes applications avec différents profils de libérations. Enfin, nous avons transposé le modèle développé avec les gels d’acrylamide pour fabriquer des lentilles de contact de 260 à 340 µm d’épaisseur à base de pHEMA contenant les microgels avec une molécule encapsulée devant être administrée dans les yeux. Nous avons modifié la composition de l’hydrogel en incorporant un polymère linéaire, la polyvinylpyrrolidone (PVP). L’obtention d’hydrogels partiellement interpénétrés améliore la rétention d’eau dans les lentilles cornéennes. L’encapsulation dans les microgels chargés négativement a donné de meilleurs rendements avec la lidocaïne et cette dernière a été libérée de la lentille de pHEMA en totalité en approximativement 2 heures qu’elle soit ou non encapsulée dans des microgels. Ainsi dans cette étude pilote, l’impact des microgels n’a pas pu être déterminé et, de ce fait, nécessitera des études approfondies sur la structure et les propriétés de la lentille qui a été développée. En utilisant des modèles de libération plus représentatifs de la physiologie de l’œil, nous pourrions conclure avec plus de certitude concernant l’efficacité d’un tel système d’administration et s’il est possible de l’optimiser.

(Appendix 1) Coral analysis and isostatic rebound effects from different Holes of IODP Expedition 310

Past sea-level records provide invaluable information about the response of ice sheets to climate forcing. Some such records suggest that the last deglaciation was punctuated by a dramatic period of sea-level rise, of about 20 metres, in less than 500 years. Controversy about the amplitude and timing of this meltwater pulse (MWP-1A) has, however, led to uncertainty about the source of the melt water and its temporal and causal relationships with the abrupt climate changes of the deglaciation. Here we show that MWP-1A started no earlier than 14,650 years ago and ended before 14,310 years ago, making it coeval with the Bølling warming. Our results, based on corals drilled offshore from Tahiti during Integrated Ocean Drilling Project Expedition 310, reveal that the increase in sea level at Tahiti was between 12 and 22 metres, with a most probable value between 14 and 18 metres, establishing a significant meltwater contribution from the Southern Hemisphere. This implies that the rate of eustatic sea-level rise exceeded 40 millimetres per year during MWP-1A.

Delamination Arrestment in Bonded-Bolted Composite Structures by Fasteners

Thesis (Ph.D.)--University of Washington, 2016-06

Monitoring genetic diversity in tropical trees with multilocus dominant markers

Since no universal codominant markers are currently available, dominant genetic markers, such as amplified fragment length polymorphism (AFLP), are valuable tools for assessing genetic diversity in tropical trees. However, the measurement of genetic diversity (H) with dominant markers depends on the frequency of null homozygotes (Q) and the fixation index (F) of populations. While Q can be estimated for AFLP loci, F is less accessible. Through a modelling approach, we show that the monolocus estimation of genetic diversity is strongly dependent on the value of F, but that the multilocus diversity estimate is surprisingly robust to variations in F. The robustness of the estimate is due to a mechanistic effect of compensation between negative and positive biases of H by different AFLP loci exhibiting contrasting frequency profiles of Q. The robustness was tested across contrasting theoretical frequency profiles of Q and verified for 10 neotropical species. Practical recommendations for the implementation of this analytical method are given for genetic surveys in tropical trees, where such markers are widely applied.

Matrix effects: The Achilles heel of quantitative high-performance liquid chromatography-electrospray-tandem mass spectrometry

High-performance liquid chromatography coupled by an electrospray ion source to a tandem mass spectrometer (HPLC-EST-MS/ MS) is the current analytical method of choice for quantitation of analytes in biological matrices. With HPLC-ESI-MS/MS having the characteristics of high selectivity, sensitivity, and throughput, this technology is being increasingly used in the clinical laboratory. An important issue to be addressed in method development, validation, and routine use of HPLC-ESI-MS/MS is matrix effects. Matrix effects are the alteration of ionization efficiency by the presence of coeluting substances. These effects are unseen in the chromatograrn but have deleterious impact on methods accuracy and sensitivity. The two common ways to assess matrix effects are either by the postextraction addition method or the postcolumn infusion method. To remove or minimize matrix effects, modification to the sample extraction methodology and improved chromatographic separation must be performed. These two parameters are linked together and form the basis of developing a successful and robust quantitative HPLC-EST-MS/MS method. Due to the heterogenous nature of the population being studied, the variability of a method must be assessed in samples taken from a variety of subjects. In this paper, the major aspects of matrix effects are discussed with an approach to address matrix effects during method validation proposed. (c) 2004 The Canadian Society of Clinical Chemists. All rights reserved.

Italian wild hop (Humulus lupulus L.): from biodiversity evaluation to varietal selection

Hop (Humulus lupulus L.) is a dioecius perennial plant. The cultivation is specific for female plants, used mainly for brewing and pharmacology. Female inflorescence, known as cone or strobili, contains bitter acids, essential oil and polyphenols. Commercial hop cultivation provides better results in regions between 45 and 55 degrees north or south in latitude, an area that also includes the northern part of Italy, where hop is endemic. Despite several studies have been conducted on the characterization of wild hops biodiversity in the U.S.A. and Europe, a lack in literature concerning the description of Italian wild hops genetic variability is still present. The increasing request of hop varieties improved in important traits, like diseases, resistance and valuable aroma profile, is bringing the hop industry. Moreover, Italian agricultural sector needs new impulse to be competitive in the market. In this view, Italian wild hop biodiversity is a resource, useful for the obtaining of Italian hop varieties, characterized by peculiar aromatic traits and more adaptable to Mediterranean climate, making their cultivation more sustainable. Based on this consideration, the present Ph.D. thesis deals with the evaluation of the Italian hop biodiversity, through the characterization of the wild samples under different point of view. The project started with the recovery of wild hop samples in different areas of north of Italy to consitue a collection field, where 11 commercial cultivars of US and European origin were grown, to have a complete vision of the hop panorama. Ph.D. project followed different research lines, the results of each one contributed to completly characterize the northern Italian hop wild biodiversity: • the morphological description showed a high phenological variability (Study 1); • the genetic characterization confirmed the rich biodiversity of the Italian population and showed a significant genetic distance between Italian genotypes and the commercial cultivars, taken in consideration (Study 2); • the need of an early sex discrimination method leads to an improvement of a genetic marker, developing a more efficient marker (Study 3); • a complete morphologic, genetic and chemical analysis of plants gave results to select the most promising genotypes (Study 4); • the comparison between the performance of wild hops and commercial cultivars in the same collection field indicated that some wild genotypes had a higher environment adaptability (Study 5); • the evaluation of the terroir, obtained comparing commercial cultivars in the collection field and the same genotypes purchased in the market, showed the influence of the northern Italian environment on the aromatic profile (Study 5); • a new analytical method for the revelation of bioactive metabolites and a simple extraction procedure were developed (Study 6). In conclusion, the Ph.D. thesis, contains the first characterization of Italian wild hop, made under field condition. The present study: i) permits to obtain a complete and significative description of the genotypes; ii) allows the identification of the most promising wild Italian genotypes; iii) allows the identification of commercial cultivars more adaptable the northern Italian climate.

ANÁLISE DO DISCURSO RELIGIOSO: MARCAS DA PÓS-MODERNIDADE NAS PRÉDICAS DE UMA IGREJA METODISTA NO ABC

Este trabalho, situado na área de Práxis Religiosa e Sociedade, analisa a interação entre o protestantismo brasileiro e a Pós-modernidade, possibilitando uma observação de certas mudanças e/ou transformações que este intercâmbio provoca neste setor religioso aproximando-o ou distanciando de algumas características próprias de suas origens protestantes. Para tanto, restringe-se ao metodismo, especificamente, uma Igreja Metodista no ABC e, por meio de uma pesquisa qualitativa, avalia como algumas marcas pósmodernas circulam nas prédicas proferidas na comunidade escolhida, ou seja, a Igreja Metodista em Santo André. O método analítico utilizado é a Análise do Discurso de linha bakhtiniana, cuja apreciação avalia a prédica como discurso verbal relacionado a uma situação social extraverbal que o engendra. Entretanto, nesta proposta de reflexão crítica, faz-se uso, também, das contribuições profícuas de outras áreas do saber, isto é, da Teologia (homilética) e da Sociologia do Protestantismo que permitem uma compreensão mais ampla dos assuntos tratados.(AU)