The processing and properties of novel polymer-based nano-composite (PNC) dielectrics for capacitor applications has been studied. PNCs were fabricated via a vacuum based deposition technique and their micro/nano-structure, chemical and dielectric properties investigated. After process development and optimisation, co-deposited Al and nylon-6 PNCs had a dielectric constant k∼7 at an approximate Al volume fraction of 0.3 that agreed with analytical predictions if it was assumed that the Al transformed to an oxide in-situ and/or after deposition. The significant effect of absorbed water vapour and temperature on PNC dielectric properties was revealed using different types of post-deposition heat treatment. Alternately-deposited PNCs consisting of Al or Ag 2-20 nm layers sandwiched between nylon-6 layers were fabricated in which the overall PNC Al or Ag volume fraction was controlled by varying the nominal Al or Ag layer thickness. Ag layers comprised of discrete nano-islands that produced a nano-capacitor network effect that increased k to ∼11. In the case of Al layers, when the layer thickness was ≥ 5 nm, corresponding to a nominal volume fraction of 0.1, Al (core)-oxide (shell) nanoparticles were formed and the PNC dielectric constant increased to ∼19. The detailed nano-structure of the core-shell particles was studied using various types of transmission electron microscopy (TEM), and the elevations in dielectric constant ascribed to multiple-interface polarisation effects dependent on the formation of the core-shell structure. PNCs based on alternate deposition of Ti sandwiched in nylon-6, and then both Ti and Ag in nylon-6 were also fabricated, with k reaching ∼73 for Ag+Ti/nylon-6 PNCs. As well as Ti-based core (metal)-shell (oxide) particles, the Ag volume fraction was sufficiently high in the 10 nm nylon-6 layers to again form a nano-capacitor network that contributed to the overall device capacitance and effective dielectric constant. Again, various types of high magnification TEM were critical in resolving the Ti-based core-shell structure and its role in high-k behaviour. The vacuum-based alternate deposition technique has been developed to offer ease of operation, reliability, flexibility and applicability to chemically different filler and matrix systems in the fabrication of high-k PNC based capacitors, in which high-k performance relies critically on the formation of core (metal)-shell (oxide) particles in both Al and Ti based systems.

Dans le cadre du développement des nanotechnologies pour les sciences de la vie et de la santé, les nanovecteurs magnétiques connaissent un essor considérable. Ces structures composites constituées de sphères polymériques encapsulant des nanoparticules magnétiques ou d`un coeur nanoparticulaire magnétique entouré d`une couverture organique présentent une combinaison de propriétés physico-chimiques et magnétiques très performante pour le diagnostic en imageries par exemple, notamment Imagerie par Résonance Magnétique (IRM), ou la thérapie : vectorisation pharmaceutique ciblée, hyperthermie thérapeutique…L`obtention de tels vecteurs avec une taille nanométrique permet l`injection intraveineuse chez les patients et la propagation dans l`organisme, tout en augmentant l`action liée à la surface spécifique. Les présents travaux de doctorat ont porté sur deux familles importantes de nanovecteurs magnétiques : - des nanosphères de polymère biocompatible chargé en composé radioactivable et encapsulant des nanoparticules de magnétite, pour la thérapie tumorale - des agents de contraste pour l`IRM de l`inflammation vasculaire ou cérébrale chez la souris, constituée d`un coeur nanoparticulaire d`oxyde de fer (maghémite ou magnétite) entourée d`une enveloppe organique pour le ciblage de la région visée (ultrasmall superparamagnetic iron oxide – USPIO, en anglais) Pour cerner le comportement de ces nanovecteurs en interaction avec le milieu liquide de suspension, puis avec les régions ciblées dans l`organisme, une approche physique multiéchelle de leurs structure et propriétés a été développée. Les études structurales des nanovecteurs ont été menées à bien grâce à des développements innovants s`appuyant sur les microscopies électroniques à résolution nanométrique. Par l`application du mode Wet-STEM, un nouveau mode en transmission de microscopie électronique à balayage environnementale, l`image en transmission de la structure interne organique/nanoparticule(s) magnétiques(s) a été obtenue et les simulations d`images par méthode de Monte Carlo ont montré qu`une résolution nanométrique pouvait être obtenue. Pour les nanovecteurs en environnement tissulaire, on a utilisé la microscopie électronique en transmission (MET) pour laquelle on a fait varier le degré de coloration dans des préparations de tissus ex vivo inclus en résine ; on a ainsi obtenu les premières images MET en haute résolution (METHR) spatiale d`agents de contraste USPIO cristallisés dans les tissus de l`aorte ou la rate chez la souris athérotique. En combinant ces études structurales avec la mesure des propriétés magnétiques par SQUID, un suivi longitudinal d`agents USPIO injectés chez la souris pour l`IRM de la plaque d`athérome a été menée à bien dans l`aorte et la rate : les résultats ont été interprétés en terme d`agglomération de particules à taille variable en fonction du temps de séjour dans l`organisme et confrontés à un modèle in vitro de dégradation en milieu acide (métabolisme lysosomal). / As applications of nanotechnologies for life and health sciences get booming, magnetic nanovectors undergo a considerable development. Such composite structures made from polymer spheres encapsulating magnetic nanoparticles or from a nanoparticular magnetic core surrounded by an organic coverage exhibit a combination of physical, chemical and magnetic properties very appropriate for diagnostic by imaging such as Magnetic Resonance Imaging (MRI), or for therapy: targeted pharmaceutical vectorization, therapeutic hyperthermia... When such vectors exhibit a nanometric size, intravenous injection and easy spread in the body of the patients are allowed, while effects related to the specific surface area are increased. The present doctoral work was concerned by two important families of magnetic nanovectors: - nanospheres of biocompatible polymer having loaded a radioactivable compound for tumoral therapy and having encapsulated magnetite nanoparticles for diagnostic by MRI: a system for thera-diagnostic is thus obtained.- contrast agents for MRI of vascular or cerebral inflammation, consisting of a nanometric iron oxide (maghemite or magnetite) core i.e. ultrasmall superparamagnetic iron oxide – USPIO - surrounded by an organic coverage for targeting the affected region. These USPIO were used to study inflammation in the atherotic plaque of the aorta in a murine model.Most of the time, such nanovectors are administered to the patients in liquid suspensions by intravenous injection. It is thus crucial to characterize both the collective behaviour and the individual structure of the vectors in liquid suspension. On the other hand their interactions with the targeted regions in the body have to be understood. For this purposes, a multiscale approach of the structure and properties of such nanovectors has been developed, with structural studies carried out through innovative developments based on electron microscopies down to subnanometric resolution and correlated with physical properties. To achieve characterization of nanovectors in liquid media we have developed the application of Wet-STEM, a new mode in transmission of environmental scanning electron microscopy (ESEM), to image the internal structure of the magnetic nanoparticles in liquid suspension and image calculations by Monte Carlo simulations have shown that a nanometric resolution could be theoretically achieved. By the same technique, stability or tendency to flocculation in suspensions can be evidenced with respect to the collective behavior of different nanovectors.In a second step we have investigated the interactions of the nanoparticles with targeted regions. The biodistribution and biotransformation of the USPIO contrast agents in the tissular and cellular environments were investigated at increasing spatial resolution using different techniques. The biodistribution of a MRI contrast agent grafted with a fluorophore, in ex vivo samples from atherotic aorta and spleen were revealed by biphoton microscopy with a resolution of a few hundred nanometers, down to macrophage scale. Then preparation of ex vivo samples for transmission electron microscopy (TEM) was adapted from standard protocols especially with respect to staining after inclusion in resin. This way, the first high resolution HR(TEM) images and electron diffraction patterns of crystallized USPIO contrast agents in the aorta or the spleen of an atheromatous mouse were obtained. Combining such structural studies with measurement (using a SQUID setup) of magnetic properties, a longitudinal follow-up of USPIO nanoparticles injected in mice for MRI of the atherotic plaque has been completed for USPIO particles embedded in the aorta and the spleen: the results were interpreted in terms of agglomeration of the particles with a decreasing size depending on time after injection and found consistent with a model of in vitro degradation in acidic environment proposed to mimick the lysosomal metabolism.

Superalloys based on platinum-group metals (PGMs) are being developed for high temperature applications. Currently, the optimum alloy is Pt84:Al11:Ru2:Cr3, and work is ongoing. Niobium is a possible addition to increase the melting point, but limited phase diagram data are available. Although work has been done on the Pt-Al-Nb system, there are no reported data for Pt-Cr-Nb. This is a study of the Pt-Cr-Nb system. As-cast samples of the Pt-Cr-Nb ternary system were investigated using scanning electron microscopy with energy-dispersive X-ray spectroscopy, and X-ray diffraction. The results were used to plot a solidification projection and all binary phases extended into the ternary, except for α´Pt, which was not identified in this investigation. The extensions of the binary phases were: (Cr) ~2 at.% Nb; (Pt) ~24 at.% Nb and 65 at.% Cr; (Nb): ~12 at.% Pt and ~17 at.% Cr; ~NbPt2: ~20 at.% Cr; ~NbCr2: ~18 at.% Pt; ~Cr3Pt: ~10 at.% Nb; ~βNbPt3: ~4 at.% Cr and ~Nb1-XPt1+X: ~13 at.% Cr. Five ternary phases were identified: τ1:~Nb17:Cr64:Pt19; τ2:~Nb28:Cr55:Pt17; τ3:~Nb30:Cr30:Pt40; τ4:~Nb45:Cr27:Pt28 and τ5:~Nb40:Cr18:Pt42. The liquidus surface was derived using the binary phase diagrams, identified primary phases, solidification sequences and the solidification projection, together with the eutectic compositions. Nineteen ternary invariant reactions were identified. Hardness measurements were made on all samples, and also toughness and fracture toughness were deduced. Alloys with (Pt) and ~NbPt2 were ductile with reasonable hardness. Alloys containing (Cr), (Nb), ~Cr3Pt, ~NbCr2, ~Nb3Pt and ~Nb2Pt were extremely brittle with cracks, whereas alloys containing ~βNbPt3 and ~Nb1-XPt1+X phases were slightly brittle.

Nous avons analysé par cryomicroscopie électronique la morphologie et la structure de longues chaines d’ADN condensées par un polycation tétravalent, la spermine (polyamine). Les expériences ont été réalisées i) avec des solutions de chaînes diluées et ii) avec des chaines isolées confinées dans la capside d’un virus.Les expériences ont été réalisées avec de l’ADN Lambda (48kbp) en solution diluée (0.03 mM Ph) et à faible concentration ionique (10 mM Tris HCl, 1 mM EDTA, pH 7.6). Nous avons exploré une large gamme de concentrations en spermine, allant du seuil de précipitation (0.05 mM sp) jusqu’à la limite de re-solubilization et au-delà (400 mM sp). Seize minutes après mélange de l’ADN et de la spermine, les échantillons sont piégés en film mince et vitrifiés à basse température pour garder intactes les conditions ioniques, puis imagés à basse température sous faibles doses d’électrons (cryoMET). La plupart des chaînes d’ADN forment des agrégats de tores de structure hexagonale avec des interdistances entre hélices de 2.93, 2.88, et 2.95 nm pour des concentrations en spermine respectivement égales à 0.05, 1 et 100 mM spermine, ce qui est en bon accord avec les données collectées précédemment par diffraction des rayons X. A concentration plus élevée en spermine (200mM), les tores hexagonaux sont remplacés par des faisceaux cholestériques de structure plus lâche (3.32 nm entre hélices). Nous en déduisons que la forme comme la structure des condensats cristallins liquides ADN-sp sont liées aux interdistances entre hélices et déterminés par les conditions ioniques i.e. par l’énergie cohésive entre chaînes d’ADN. En dehors du domaine de précipitation (400mM sp), les molécules d’ADN forment un réseau soluble de fines fibres (4-6nm de diamètre) qui nous amènent à reconsidérer l’état de ces chaiînes en présence de spermine. Nous avons également conçu des expériences pour visualiser les agrégats formés 6 à 60 sec après addition de la spermine dans les mêmes conditions de tampon. Parmi les nombreuses formes originales que nous avons observées (absentes après 16 min), la présence de fibres étirées ou en hélice, visibles seulement après 9sec, nous conduit à proposer que les chaines d’ADN soient immédiatement étirées après addition de spermine puis relaxent sous forme de fibres hélicoïdales qui donnent naissance à de petits toroids (comprenant quelquefois moins d’une chaine) qui grandissent et fusionnent. Nous avons également analysé les dimensions de l’ensemble des tores observés et montré l’existence de contraintes géométriques qui restent à élucider. Puisqu’il était généralement impossible de prévenir l’agrégation des chaines d’ADN, nous avons choisi une autre approche pour analyser le collapse de chaines d’ADN individuelles. Nous avons utilisé une population de virus T5 contenant une fraction de leur génome initial (12-54 kbp). La molécule d’ADN, initialement confinée dans le petit volume de la capside (de de 80nm diamètre) est collapsée par addition de spermine. Par comparaison avec le premier jeu de données, nous avons travaillé à concentration plus élevée en ADN (0.45 mM Phosphates dans l’ensemble de l’échantillon) et la concentration en spermine a été ajustée entre 0.05 et 0.5 mM (ce qui correspond à des rapports de charges +/- bien inférieurs). Ces expériences ont donc été réalisées au voisinage de la ligne de précipitation, dans la « région de coexistence », entre le domaine où les chaines sont en condition de pelote et le domaine ou les chaines sont toutes collapsées sous forme de tores. Nous avons montré l’existence de formes intermédiaires entre ces deux états que nous appelons « tores chevelus » dans lesquels une partie de la molécule est condensées dans le tore alors que l’autre partie reste non condensée. Les distances entre hélices ont également été mesurées. Elles sont plus grandes dans ces structures intermédiaires que dans les tores formés à plus forte concentration en spermine. Ces deux séries d’expériences montrent l’intérêt des méthodes de cryo-microscopie pour étudier la structure locale des phases condensées de l’ADN. Nous avons montré comment le confinement modifie le comportement de l’ADN en solution et l’intérêt d’étudier ces effets compte tenu de son importance dans le contexte biologique. / By using cryo-electron microscopy, we analyzed the morphology and structure of long double-stranded DNA chains condensed upon addition of varying amounts of the tetravalent polycation spermine (polyamine). Experiments have been performed i) with chains diluted in the bulk and ii) with individual chains confined in a virus capsid.Bulk experiments have been done with lambda DNA (48.5 kbp) at low concentration (0.03 mM Ph) and in low salt conditions (10 mM Tris HCl, 1 mM EDTA, pH 7.6). We explored a wide range of spermine concentration, from the onset of precipitation (0.05 mM sp) up to above the resolubilization limit (400 mM sp). Sixteen min after mixing spermine and DNA, samples have been trapped in thin films and vitrified in liquid ethane to keep ionic conditions unchanged, and imaged at low temperature with low doses of electrons (cryoTEM). DNA chains mostly form large aggregates of toroids in which DNA chains are hexagonally packed with interhelical spacings of 2.93, 2.88, and 2.95 nm at 0.05, 1 and 100 mM spermine, respectively, in agreement with previous X-ray data. At higher spermine concentration (200 mM), hexagonal toroids are replaced by cholesteric bundles with a larger interhelical spacing (3.32 nm). We conclude that the shape and the structure of the liquid crystalline sp-DNA condensates are linked to the DNA interhelix spacing and determined by the ionic conditions i.e. by the cohesive energy between DNA strands. Outside of the precipitation domain (400 mM spermine), DNA chains form a soluble network of thin fibers (4-6 nm in diameter) that let us reconsider the state of these DNA chains in excess of spermine. We also designed experiments to visualize condensates formed 6-60 sec after mixing Lambda DNA with 0.05 mM spermine, under identical buffer conditions. Among multiple original shapes (not found after 16 min), the presence of stretched and helical elongated fibers seen only 9sec after addition of spermine let us propose that DNA chains are immediately stretched upon addition of spermine, relax into helical structures and finally form small toroids (containing in some cases less than one Lambda chain) that further grow and aggregate. We also analyzed the dimensions and structural details of the complete collection of toroids, and reveal the existence of geometric constraints that remain to be clarified. Since it was only exceptionally possible to prevent the aggregation of DNA in dilute solution, we used another approach to observe the collapse of single DNA chains. We handled a population of T5 viruses containing a fraction of their initial genome (12-54 kbp long). The Na-DNA chain, initially confined in the small volume of the capsid (80nm in diameter) is collapsed by the addition of spermine. Compared to the first set of experiments, we explored a higher DNA concentration range (0.45 mM Phosphates in the whole sample) and the spermine concentration was varied from 0.05 to 0.5 mM (which corresponds to much lower +/- charge ratios). Experiments are thus performed close to the precipitation line, in the coexistence region, between the region where all chains are in a coil conformation, and the region where all chains are collapsed into toroids. We describe the existence of intermediate states between the coil and the toroidal globule that were not reported yet. In these “hairy toroids”, part of the DNA chain is condensed in the toroid and the other part stays uncondensed outside of it. The interhelical spacing was also measured; it is larger in these partly-condensed toroids than in the fully organized toroids formed at higher spermine concentration.These two series of experiments show the interest of cryoEM to analyze the structural polymorphism and local structure of spermine-DNA aggregates. We also demonstrated how the confinement interferes with DNA condensation and the interest to investigate such effects that are important in the biological context.

Este estudo teve como objetivo verificar a possibilidade de utilizar o esmalte bovino, em teste resistência de união, substituindo o esmalte humano, bem como, analisar a resistência de união, morfologia de interface e padrão de condicionamento de sistemas adesivos autocondicionantes aplicados ao esmalte intacto e asperizado. Foram usados 40 dentes humanos e 40 dentes bovinos. Cada dente foi dividido em quatro regiões, de maneira a permitir a obtenção dos corpos-de-prova de todas as condições experimentais. Três sistemas adesivos autocondicionates; Clearfil Protect Bond (Kuraray Medical inc), Adper Prompt L-Pop (3M-ESPE), i Bond (Heraeus-Kulzer) foram testados, sendo utilizado um sistema de condicionamento total, Excite (Ivoclar-Vivadent), como controle positivo. A resina Tetric Ceram foi utilizada para a confecção dos corpos-de-prova, para resistência de união e amostras de microscopia eletrônica de varredura (MEV). As médias de resistência de união foram avaliadas por análise de variância e Tukey. Não houve diferença estatística, na resistência de união, entre os substratos, embora, as médias em esmalte humano tenham sido mais altas. A interação tripla; sistema Adesivo x Tratamento x Esmalte, também não foi significante, no entanto, manteve-se a tendência dos autocondicionantes de passo único apresentar as menores médias de resistência de união, principalmente no esmalte intacto. Houve diferença estatística para o fator sistema adesivo, sendo que o menor resultado foi obtido com o adesivo i Bond, na interação sistema adesivo x tratamento, a menor média também foi obtida pelo adesivo i Bond, quando aplicado ao esmalte intacto. O fator tratamento foi significante, sendo que, na variável de esmalte asperizado constatou-se a maior média de resistência de união, evidenciando que a asperização da superfície de esmalte, quando um sistema adesivo autocondicionante é aplicado no esmalte, constitui um passo operatório essencial. As imagens de MEV evidenciaram maior porosidade no dente bovino, independente do sistema adesivo utilizado e maior descalcificação do esmalte, tanto asperizado, quanto intacto, para os adesivos Excite e Adper Prompt L-Pop. Em relação à interface observou-se, que a camada de adesivo, no esmalte asperizado, tanto humano, quanto bovino, mostrou-se mais espessa, não importando o tipo de sistema adesivo; autocondicionante ou convencional. Os prismas de esmalte, no substrato bovino, mostraram um arranjo diferenciado, do observado no esmalte humano, porém esta diferença não promoveu alteração na resistência de união, visto que, não houve diferença estatística entre os substratos. Assim na impossibilidade de se obter esmalte humano, para testes de microtração, a utilização do esmalte bovino é viável. / The aim of this study was to verify the possibility in use the bovine enamel, as a substitute to human enamel, in the microtensile bond strength test, as well as analyze the bond strength, interface morphology and etch pattern of the self etching primers (SEP) applied in the cut and uncut, bovine and human, enamel. For this 40 human teeth and 40 bovine teeth were used, each tooth was divided in four halves to obtain all experimental conditions in the same tooth. Three SEP; Clearfil Protect Bond (CPB) (Kuraray Medical Inc), Adper Prompt L-Pop (LP) (3M-ESPE), i Bond (IB) (Heraeus-Kulzer) were tested, using a conventional adhesive system, Excite (EX) (Ivoclar Vivadent), as a positive control. A bulk of composite resin, Tetric Ceram (Ivoclar Vivadent), was build up for the specimens of microtensile test and SEM. In all above trials, some specimens were randomly selected and prepared for SEM. The data collected was submitted for statistical analyze ANOVA and Tukey test. It was possible to verify that there were no statistically differences between the substrate and triple interaction Adhesive Systems x Substrate x Treatment, but in the booth conditions, the SEP, i Bond, showed the lowest means, as same as, all means in bovine enamel were lowest than in human enamel. There were statistically differences between the systems adhesives and for treatment, cut and uncut. For adhesive systems the lowest value was observed for i Bond, in booth substrate and treatment. In the treatment conditions the greater means were observed in the cut enamel, showing that the cutting enamel is essential condition, to improve the bond strength of SEP, applied in the enamel. The SEM images, for etch pattern showed that in the bovine enamel the porosity was more thickness, for all adhesives and cut and uncut treatment. It was possible to verify, trough SEM of morphology interface, that the all adhesives in cut enamel, had adhesive layer more thickness, as and exception was the SEP, I Bond, that showed adhesive layers thinner. The bovine enamel showed a different arrangement for prisms that showed in the human enamel. We conclude that when the use of human enamel, in the microtensile test, is unviable, it is possible to use the bovine enamel as a substrate.

O gênero Aegla Leach, 1820 representa o único táxon dentro de Decapoda Anomura com representantes adaptados exclusivamente a ambientes de água doce. As eglas são endêmicas da América do Sul e vivem em ambientes lóticos com alto nível de oxigenação. Estudos comparativos da morfologia de jovens recém-eclodidos podem contribuir para estabelecer relações de afinidade entre as cerca de 70 espécies já descritas que compõem a família Aeglidae. Porém, o número de trabalhos que descrevem a morfologia em detalhe nesta fase de vida é ainda escasso. O objetivo do presente estudo foi descrever detalhadamente a morfologia externa dos jovens recém-eclodidos das espécies Aegla paulensis e Aegla perobae, com base em Microscopia Óptica e em Microscopia Eletrônica de Varredura (MEV). Fêmeas ovígeras foram coletadas e transferidas para o laboratório a fim de se obter os jovens recém-eclodidos dos ovos. A descrição detalhada da morfologia do jovem recém-eclodido incluiu a carapaça, o abdome, os apêndices cefalotorácicos (antênula, antena, mandíbula, maxílula, maxila, maxilípedes, pereópodes) e a região do télson juntamente com os urópodes. As cerdas foram analisadas em detalhe quanto ao número, localização e tipo morfológico com o auxílio da MEV. Os resultados obtidos foram analisados e comparados com os das espécies que já tiveram seus jovens recém-eclodidos descritos e também com os adultos. As principais descobertas do estudo foram: as lineae aeglicae, os pleópodes rudimentares, a riqueza de tipos de cerdas e os poros sensoriais / Genus Aegla Leach, 1820 represents the one taxon within Decapoda Anomura with representatives exclusively adapted to freshwater environments. Aeglids are endemic to South America and they live in lotic environments with high levels of dissolved oxygen. Comparative studies of the newly-hatched juvenile morphology may contribute to establish affinity relations among the 70 species of the Aeglidae family already described. However, the number of studies which describe the morphology at this life phase in detail is still scarce. The objective of this study was to describe the external morphology of the newly-hatched juvenile of Aegla paulensis and Aegla perobae in detail, using Light Microscopy and Scanning Electron Microscopy (SEM). Newly-hatched juveniles were obtained from ovigerous females kept under laboratory conditions. Detailed description of the newly-hatched juveniles included the carapace, the abdomen, the cephalothoracic appendages (antennule, antenna, mandible, maxillule, maxilla, maxillipeds, pereiopods), and the telson-uropods region. SEM was used to analyze setae number, location and type. The results were analyzed and compared with those from newly-hatched juveniles already described and with adults. The main findings in this study were: lineae aeglicae, rudimentary pleopods, setae morphology diversity, and pores sensilla.

O electrospinning (deposição eletrostática) representa um método simples e conveniente para preparar bras poliméricas e bras cerâmicas com interiores sólidos ou ocos, excepcionalmente longos em comprimento, uniformes no diâmetro, variando no intervalo de dezenas de nanômetros a vários micrômetros, com diversicadas composições. Apesar da potencialidade e versatilidade da Microscopia Eletrônica de Varredura existe um grande problema de caracterizar nanobras, já que este processo não é feito automaticamente. Este trabalho apresenta uma nova metodologia para extração automática de medidas em imagens SEM, como uma alternativa eciente em relação aos softwares semi-automáticos propostos na literatura. A metodologia proposta envolve o processamento das imagens SEM usando Morfologia Matemática e os resultados obtidos são discutidos e comparados àqueles processados por Redes Neurais Celulares e pelo método de Otsu. Imagens coletadas do microscópio foram analisadas por técnicas de processamento de imagens para determinação do diâmetro das nanobras. Os resultados mostraram boa concordância entre as metodologias estudadas e o método padrão-ouro indicando que os mesmos podem substituí-lo para constituir uma alternativa automática na caracterização de nanobras. / The electrospinning technique represents a simple and convenient process to provide polymers and ceramics bers with both solid and hollow interiors that are exceptionally long in length, uniform in diameter, varying within the interval of few nanometers to several microns, and diversied in composition. Despite the versatility and potencially the scanning electron microscopy (SEM) there is a serious problem to characterize nanobers, as it is not made automatically. This work presents novel methodology software for automatic measurement in SEM images, as an eficient alternative in comparison with semi-automatic softwares proposed in literature. The proposed methodology involves the image processing SEM using Mathematical Morphology and the obtained results are argued and compared with those processing for Celullar Neural Network and Otsu method. The microscope images were assessed and analysed by imagery processing techniques to determinate diameters of nanobers. The results has shown good agreement between the investigated and gold standard methods suggesting that the same ones can substitute it to constitute an automatic alternative in the nanobers characterization.

Os sistemas de lima única constituem a mais recente tecnologia no que se refere ao preparo dos canais radiculares, e vem sendo objeto de estudo sob diversos aspectos. Uma das preocupações referentes aos sistemas automatizados é a manutenção da qualidade e segurança nos preparos quando da reutilização do instrumento. Este estudo teve como objetivo avaliar as alterações de superfície de dois sistemas de lima única - Wave One e One Shape - e seu desempenho através do tempo de preparo no decorrer dos usos. Duzentos condutos de molares inferiores humanos extraídos foram instrumentados com 10 limas Wave One e 10 limas One Shape, acompanhados de irrigação com 10 ml de Hipoclorito de Sódio 2.5%. Cada instrumento foi utilizado por 10 vezes. Os tempos para o preparo completo do canal foram registrados por um cronômetro digital e anotados em tabelas. Para avaliação em microscopia eletrônica de varredura as limas novas foram observadas assim que removidas da embalagem. Após as utilizações, os instrumentos foram limpos, esterilizados em autoclave e observados após 2, 6, 8 e 10 usos. Três avaliadores calibrados observaram as fotomicrografias e registraram de acordo com os scores propostos a presença ou ausência de alterações superficiais. O teste Kappa de concordância entre os avaliadores apresentou maioria de resultados ótimo a moderado (?=5%). Os dados referentes à avaliação das imagens foram submetidos ao teste Wilcoxon-Mann-Whitney com nível de significância de 5% (?=5%). As alterações mais observadas foram aplainamento e microcavidade. O crack foi observado nos dois instrumentos sendo significante a partir do sexto uso para Wave One e do décimo para One Shape. Os dados relativos aos tempos de preparo foram submetidos à análise estatística pelos testes Wilcoxon-Mann-Whitney, ANOVA e Mc-Nemar com nível de significância de 5% (?=5%). Os tempos de preparo registrados para One Shape foram inferiores aos tempos para Wave One. O uso influenciou os tempos de preparo sendo observado um aumento significativo para os dois instrumentos. Um instrumento One Shape fraturou mas a ocorrência não foi estatisticamente significante. / Single-file systems are the most recent technology in regard to the preparation of root canals and have been studied in several ways. One of the concerns related to automated systems is maintaining quality and safety in preparation when the instrument is reused. This study\'s aim was to evaluate the changes on the surface of two single-file systems - Wave One and One Shape - and their performance through preparation time over the uses. Two hundred root canals of extracted human molars were instrumented with 10 Wave One files and 10 One Shape files, followed by irrigation with 10 ml of sodium hypochlorite 2.5%. Each instrument was used 10 times. The time required to complete each root canal was measured by a digital stopwatch and recorded in tables. New unused files were analysed using a scanning electron microscope. After used, the instruments were cleaned and sterilized, then observed after 2, 6, 8 and 10 uses. Three calibrated evaluators observed these SEM images and listed according to the suggested scores the presence or absence of changes on the surface. The Kappa test showed mostly results from moderate to great (? = 5%). The data relating to evaluation of images was submitted to the Wilcoxon-Mann-Whitney test with a significance level of 5% (? = 5%). The most frequent changes were blunt edges and microcavities. Cracking was observed in both instruments being significant in Wave One after the sixth use and in One Shape after the tenth use. Data on preparation times were statistically analysed by the Wilcoxon-Mann-Whitney, ANOVA and Mc-Nemar tests with a significance level of 5% (? = 5%). Regarding the working time taken to shape the canals, One Shape was significantly faster than Wave One. The preparation time was affected by the number of file use increasing significantly on both instruments. A One Shape instrument fractured but the finding was not statistically significant.

A resistência de plantas daninhas é um grande problema que afeta a produtividade das culturas em nosso país, ao passo que quando é identificada, deve ser estudada visando desenvolver estratégias de manejo que evitem a expansão e seleção em novas áreas, além de seleção de resistência múltipla em áreas onde está presente. Nesta temática o objetivo desta pesquisa foi determinar manejo alternativo ao glyphosato para as espécies Chloris elata e Digitaria insularis no período de entressafra da cultura da soja e identificar características morfológicas da superfície foliar de Chloris elata que possam interferir sobre o controle com herbicidas. Foram estudadas alternativas ao glyphosate para manejo em áreas de sistema de produção soja/milho, em dois experimentos com as plantas daninhas Chloris elata e Digitaria insularis perenizadas e com duas condições de roçada (15 e 30 cm). Foram avaliados o controle visual das plantas daninhas, redução de matéria fresca e seca. Para morfologia das folhas da espécie Chloris elata foi realizada análise histológica com recursos de microscopia eletrônica de varredura, visando caracterizar a morfologia da folha, além de determinar o índice estomático, densidade estomática e densidade de tricomas para as superfícies adaxial e abaxial das folhas, nos estádios 4 e 6 folhas totalmente expandidas. Digitaria insularis se mostrou menos suscetível as técnicas de manejo empregadas para plantas perenizadas, necessitando duas aplicações sequenciais para conter a rebrota dos tratamentos. O uso da maior dose do herbicida haloxyfop associado aos herbicidas glyphosate ou amônio-glufosinato se mostrou eficaz no controle de C. elata e D. insularis. O manejo de roçagem potencializou a ação dos herbicidas, e a planta daninha D. insularis se mostrou mais suscetível a está técnica em relação ao C. elata. Para este manejo a associação da maior dose de haloxyfop ao glufosinato foi eficaz para as duas gramíneas. As alturas de roçagem somente se diferenciaram nas primeiras avaliações. O biótipo resistente de C. elata apresentou menor densidade estomática, no estádio de 4 folhas completamente expandidas e maior densidade de tricomas no estádios de 6 folhas completamente expandidas, o que pode contribuir para a resistência ao glyphosate. Está espécie apresentou formações de cristais de cera que circundam o ostíolo, no estádio de 6 folhas completamente expandidas, podendo estar relacionada a a menor suscetibilidade ao glyphosate desta planta daninha perenizada. / Weed resistance is a major problem that affects crop productivity in our country, whereas when it is identified, it must be studied in order to develop management strategies that avoid expansion and selection in new areas, as well as multiple resistance selection in areas where it is present. In this subject the objective of this research was to determine alternative management of glyphosate for the Chloris elata and Digitaria insularis species during the off - season of the soybean crop and to identify the morphological characteristics of the leaf surface of Chloris elata that could interfere the control with herbicides. It was studied alternatives to glyphosate for management in areas of soybean / maize production system in two experiments with weeds Chloris elata and Digitaria insularis perennial and with two mowing conditions (15 and 30 cm). The visual control of weeds, fresh and dry matter reduction were evaluated. For the morphology of the leaves of the Chloris elata species, a histological analysis was carried out using scanning electron microscopy to characterize the leaf morphology, as well as to determine the stomatal index, stomatal density and trichome density for the adaxial and abaxial surfaces of the leaves, stages 4 and 6 fully expanded leaves. Digitaria insularis was less susceptible to the management techniques used for perennial plants, requiring two sequential applications to contain the regrowth of treatments. The use of the highest dose of the herbicide haloxyfop associated with the herbicides glyphosate or ammonium glufosinate proved to be effective in the control of C. elata and D. insularis. Herbicide management potentiated herbicide action, and D. insularis weed was more susceptible to this technique than C. elata. For this management, the association of the highest dose of haloxyfop to glufosinate was effective for both grasses. The cutting heights differed only in the first evaluations. The resistant C. elata biotype showed lower stomatal density at the stage of 4 fully expanded leaves and greater density of trichomes in the stages of 6 fully expanded leaves, which may contribute to resistance to glyphosate. This species presented waxy crystal formations that surround the ostrich, in the stage of 6 fully expanded leaves, and may be related to the natural tolerance to the glyphosate of this perennial weed.

O objetivo desse estudo foi comparar o desempenho de ligaduras ortodônticas estéticas de 4 marcas comerciais, após 30 dias na cavidade bucal, com o uso de dentifrício clareador e convencional para avaliar: alteração de cor por meio da espectrofotometria; a ultraestrutura da superfície por meio da Microscopia Eletrônica de Varredura (MEV); propriedade elástica por meio do teste de tração. Foram avaliadas as ligaduras seguintes marcas comerciais: American Orthodontics, 3M Unitek, Orthotechnology e Morelli Ortodontia. Foram selecionados, após o cálculo amostral, 20 pacientes que atenderam aos critérios de inclusão. Os pacientes receberam, de forma aleatória, com o auxílio do acessório Shooter (TP Orthodontics, La Porte, IN, EUA) ligaduras nos elementos 13, 23, 33 e 43; 32, 31, 41 e 42. No mesmo dia receberam dentifrício clareador Colgate Luminous White (Colgate-Palmolive Indústria e Comércio, São Bernardo do Campo, SP, Brasil) que foi usado por 30 dias (grupo experimental). Após esse período as ligaduras foram removidas, armazenadas (em saliva artificial) e, imediatamente submetidas aos testes. Os pacientes receberam, então, dentifrício convencional Colgate Máxima Proteção Anti-cáries (Colgate-Palmolive Indústria e Comércio, São Bernardo do Campo, SP, Brasil) (grupo controle). Após 30 dias, foram removidas, armazenadas e submetidas aos ensaios. As ligaduras inseridas nos bráquetes dos caninos foram avaliadas para alteração de cor pelo espectrofotômetro (Vita Easyshade Zahnfabrik, Bad Säckingen, Alemanha). Em seguida, as ligaduras, de cada marca, que apresentaram maior e menor variação de cor com o dentifrício clareador e convencional, bem como ligaduras novas, foram submetidas à avaliação qualitativa com a visualização pelo Microscópio Eletrônico de Varredura (EVO 50, Carl Zeiss, Cambridge, Inglaterra). As ligaduras que estavam inseridas nos bráquetes incisivos inferiores foram submetidas ao teste de tração pela Máquina de Ensaio Mecânico Universal (EMIC DL 2000, São José dos Pinhais, PR, Brasil). Os achados foram submetidos à análise estatística ANOVA e ao teste complementar de Duncan em um nível de significância de 5%. Os resultados mostraram que o dentifrício clareador não conseguiu efetivamente manter a estabilidade de cor das ligaduras ortodônticas estéticas. O valor final para o ΔE (variação total de cor) para todas as marcas foi > 3,3 o que indica uma alteração clinicamente perceptível pelo olho humano e que sinaliza a reposição do material por razões estéticas. Em relação à MEV as imagens obtidas foram heterogêneas e não permitiram caracterizar um padrão para um ou outro dentifrício. No que se refere ao teste de tração, houve melhor desempenho para as marcas 3M Unitek e American Orthodontics. O tipo de dentifrício, clareador ou convencional, não alterou a propriedade elástica entre as marcas estudadas. Pode-se concluir, pela presente pesquisa, que o dentifrício clareador não foi capaz de alterar a estabilidade de cor nas 4 marcas avaliadas por um período de 30 dias. A avaliação qualitativa pela MEV não permitiu concluir se a abrasividade do dentifrício clareador trouxe danos ou injurias à superfície das ligaduras. Apesar disso, o seu uso não alterou a propriedade elástica das mesmas. / The objective of this study was to compare the performance of aesthetic orthodontic ligatures/modules of 4 commercial brands, after 30 days in the oral cavity, with the use of conventional and whitening dentifrice to evaluate: color change by spectrophotometry; the ultrastructure of the surface by Scanning Electron Microscopy (SEM); elastic property by the tensile test. The following brands were evaluated: American Orthodontics, 3M Unitek, Orthotechnology and Morelli Orthodontics. Twenty patients who were included in the inclusion criteria were selected after sample calculation. Patients received, at random, with the aid of the Shooter accessory (TP Orthodontics, La Porte, IN, USA) ligatures on elements 13, 23, 33, 43, 32, 31, 41 e 42 and whitening dentifrice Colgate Luminous White (Colgate-Palmolive Indústria e Comércio, São Bernardo do Campo, SP, Brazil), which was used for 30 days (test group). After this period, the ligatures were removed, stored (in artificial saliva) and immediately submitted to the tests. Patients were then given conventional toothpaste Colgate Maximum Anti-caries Protection (Colgate-Palmolive Indústria e Comércio, São Bernardo do Campo, SP, Brazil). This was the control group. Once again, after 30 days, the modules were removed, stored and submitted to assays. Ligatures inserted into the canine brackets were evaluated by the spectrophotometer (Vita Easyshade Zahnfabrik, Bad Säckingen, Germany) to evaluate the color change. After this step, the ligatures of each brand, which presented greater and lesser color variation, both with the whitening dentifrice as well as the conventional one, and new ligatures, were selected for qualitative evaluation with the visualization by the Scanning Electron Microscope (EVO 50, Carl Zeiss, Cambridge, England). The ligatures that were inserted in the lower incisor brackets were subjected to the tensile test by the Universal Mechanical Testing Machine (EMIC DL 2000, São José dos Pinhais, PR, Brazil). The findings were submitted to ANOVA statistical analysis and Duncan\'s complementary test at a significance level of 5%. The results showed that the whitening dentifrice failed to effectively improve the color stability of aesthetic orthodontic ligatures. The final value for ΔE (total color change) for all brands was > 3.3 which indicates a change clinically perceptible by the human eye and signaling the replacement of the material for aesthetic reasons. In relation to the SEM the images obtained were heterogeneous and did not allow to characterize a standard for one or the other dentifrice. Regarding the tensile test, there was better performance for the brands 3M Unitek and American Orthodontics. The type of dentifrice, whitening or conventional did not alter the elastic property between the brands studied. It can be concluded from the present research that the whitening dentifrice was not able to change the color stability in the 4 brands evaluated for a period of 30 days. The qualitative evaluation by SEM did not allow the conclusion that the abrasiveness of the whitening dentifrice caused damage to the surface of the ligatures. Despite this, their use did not alter their elastic property.