925 resultados para MICRODOMAIN MORPHOLOGY


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The gross morphology of digestive tube of Macuxitermes triceratops is described and illustrated. The gut of this species is very similar to those of Embiratermes and Ibitermes, and does not show any obvious autopomorphic character. The phylogenetic relations of this genus are discussed based on the available evidence, and it is concluded that it is probably the sister group of Armitermes + Curvitermes + Cryilliotermes.

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The dynamic scale theory and fractal concepts are employed in the characterization of surface morphological properties of layer-by-layer (LBL) films from poly(o-methoxyaniline) (POMA) alternated with poly(vinyl sulfonic acid) (PVS). The fractal dimensions are found to depend on the procedures to fabricate the POMA/PVS multilayers, particularly with regard to the drying procedures. LBL films obtained via drying in ambient air show a more homogeneous surface, compared to films dried under vacuum or a flow of nitrogen, due to a uniform rearrangement of polymer molecules during solvent evaporation.

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The physicochemical properties and morphology of spongolite, a fibrous hollow material from Mato Grosso do Sul State (Brazil) have been studied. The results of thermal analysis, scanning electron microscopy (SEM), X-ray diffraction and NMR spectroscopy indicated that external and internal surfaces of silica spicules are covered by silica gel layers. The water evolved in the range 120-350degreesC is the result of silanol groups condensation to siloxane bonds. Total homogenization of the needles is achieved by heating spongolite over 900degreesC. This mineral may be considered as a natural composite material containing surface-immobilized reactive species. The presence of active silica gel layers opens the possibilities of attaching functional groups to spongolite surface. (C) 2002 Elsevier B.V. B.V. All rights reserved.

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Morphology of three samples of alumina are investigated. Infrared spectra are analysed by use of their morphology through the theory of average dielectric constant. Crystal shape is obtained from X-ray diffraction patterns by reflection intensity ratio. In the case of electron scanning microscopy, shape factor was obtained by an average axial ratio of the particles. Comparison of results show that there is agreement among these techniques and infrared spectra can be used to determine the morphology of alumina particles from 2.7 to 10 mu m, even for heterogeneous samples. (C) 1999 Elsevier B.V. B.V. All rights reserved.

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Aims: To report nine additional well-defined cases with infiltrative myelopathy by paracoccidioidomycosis (PCM), to describe the specific lesions and infection-related stromal abnormalities, to review the literature on this type of involvement and to introduce a new cause of granulomatous lesions of bone marrow.Methods and results: Different bone marrow specimens were studied (aspirated smears, aspirated clots, biopsy imprints and biopsies) from nine patients with acute or subacute forms of PCM known to have PCM infiltrative myelopathy.Conclusions: the biopsy specimens were the best for demonstrating bone marrow involvement by PCM. The lesions varied from compact and focal granulomas with few fungal cells to numerous disseminated fungal cells within a loose granulomatous inflammatory reaction, with a continuum between these extremes suggesting a spectrum of immune response to the fungi. Other findings such as bone marrow fibrosis, parenchymal coagulative necrosis and bone necrosis were also observed in the affected areas.

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The present work showed that the newly emerged queen weight, the number of ovarioles. and the spermatheca mass are not influenced by the sizes of the wax cups. The first two characters suffered time transference influence, and the best acceptances were obtained mainly, in wax cups with diameters of 7, 8, and 9 min.

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A polymeric precursor method was used to synthesis PbTiO3 amorphous thin film processed at low temperature. The luminescence spectra of PbTiO3 amorphous thin films at room temperature revealed an intense single-emission band in the visible region, the visible emission band was found to be dependent on the thermal treatment history, Photoluminescence properties Versus different annealing temperatures were investigated. The experimental results (XRD, AFM, FL) indicate that the nature of photoluminescence (PL) must be related to the disordered structure of PbTiO3 amorphous thin films, Copyright (C) 2000 John Wiley & Sons, Ltd.

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Atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) are used to investigate molecular organization in Langmuir-Blodgett (LB) films of two kinds of lignins. The lignins were extracted from sugar cane bagasse using distinct extraction processes and are referred to here as ethanol lignin (EL) and saccharification lignin (SAC). AFM images show that LB films from EL have a flat surface in comparison with those from SAC. For the latter, ellipsoidal aggregates are seen oriented perpendicularly to the substrate. This result is confirmed by a combination of transmission and reflection FTIR measurements, which also point to lignin aggregates preferentially oriented perpendicularly to the substrate. For LB films from EL, on the other hand, aggregates are preferentially oriented parallel to the substrate, again consistent with the flat surface observed in AFM data. The vibrational spectroscopy data for cast films from both lignins show random molecular organization, as one should expect.

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In this study, the effect of bismuth content on the crystal structure, morphology and electric properties of barium-bismuth-tantalate (BBT) ceramics was explored with the aid of X-ray diffraction (XRD), scanning electron microcopy (SEM), dielectric properties and ferroelectric hysteresis loops. BaBi2Ta2O9 (BBT) ceramics have been successfully prepared by the solid-state reaction. The BBT phase was crystallized at 900 degreesC for 2 h. The excess of bismuth controls the grain size, affecting the density of the material. Measurements of dieletric constant and dieletric losses confirm that the material is a ferroeletric with a Curie temperature around 77 degreesC. The dieletric constant measured at room temperature was 400, with a dielectric loss of 0.03. Both the phase-transition behaviour and ferroelectric properties, such as spontaneous polarization (P-s), showed a dependence on Bi content. (C) 2004 Elsevier B.V. All rights reserved.

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We present atomic force microscopic images of the interphase morphology of vertically segregated thin films spin coated from two-component mixtures of poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene-vinylene] (MEH-PPV) and polystyrene (PS). We investigate the mechanism leading to the formation of wetting layers and lateral structures during spin coating using different PS molecular weights, solvents and blend compositions. Spinodal decomposition competes with the formation of surface enrichment layers. The spinodal wavelength as a function of PS molecular weight follows a power-law similar to bulk-like spinodal decomposition. Our experimental results indicate that length scales of interface topographical features can be adjusted from the nanometer to micrometer range. The importance of controlled arrangement of semiconducting polymers in thin film geometries for organic optoelectronic device applications is discussed. (c) 2007 Elsevier Ltd. All rights reserved.

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We present a description of the external morphology and internal oral features of the tadpole of Scinax catharinae and comparisons with the known tadpoles of the S. catharinae group. Two characters of the external morphology present some intraspecific variation: the row of submarginal papillae, which can be uniseriate or absent, and the tail tip, which can be large or small, truncated or not. That said, the tadpole of S. catharinae presents some distinguishing features that differentiate it from other tadpoles in the S. catharinae group: i) the marginal row of papillae with alternate disposition, ii) the spiracle opening on the midline of the body, iii) longest snout length, and iv) largest interorbital distance. The studied species were segregated into five ecomorphological guilds, characterized by external morphological features, tadpole habitat use and vegetation formation of species range. The taxonomy of the S. catharinae group is complex, due to the morphological similarities among the adults. Larval characters could help in the resolution of the taxonomic and phylogenetic complexities, since the morphological differences among the tadpoles in this group seem more conspicuous than those found among the adults.