1000 resultados para Morphological filters


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Dypsis leptocheilos (Hodel) Beentje & J. Dransf. palms are widely used in landscaping, however there is a lack of studies about its biology, especially on the morphology of its seedling disseminules and the ideal seed storage time without loss of viability. The objectives of this work were to describe the morphological aspects and to study the storage effect on the germination of D. leptocheilos seeds. The experiments were performed at FCAV/UNESP, Jaboticabal Campus, São Paulo State, Brazil. In order to obtain a morphology description 100 disseminules were sowed in vermiculite. The external and internal sides of the disseminules as well as the representative phases of the germination process were sketched with the help of a light chamber attached to a stereomicroscope. Five treatments were arranged in order to study the storage effects on the seeds (four months of storage and straight after harvest), with four replicates with 25 disseminules each (seeds with attached endocarp) in a completely randomized design. The germination test was conducted over a 140 days period and noted every two days. In order to calculate the germination percentage (% G) and the Germination Speed Index (GSI), the seeds were considered germinated when the germinative button appeared. The data were submitted to a polynomial regression analysis to verify the behavior of the variables over the storage period. The D. leptocheilos seeds have rounded shape, ruminate endosperm and hard consistency. The embryo is lateral, peripheral and relatively undifferentiated, with approximately 3 mm long and conical shape. The germination percentage increased from 17% for seeds sowed straight after harvest to 73% for those stored over a three-month period. For the GSI the increase was about 0.85%. It was concluded that the germination of D. leptocheilos is of an adjacent ligulate type. Furthermore, the seeds stored for 3 months at 14 degrees C showed both higher percentage and germination speed.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The aim of this study was to investigate the effect of high fat diet and different frequencies of swimming programs in the tibial anterior muscle in male Wistar rats. In conclussion, the aerobic training during two days/week and five days/week caused injuries in muscle fibers and the high fat diet did not cause statically significant results compared to normal diet.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Thin solid films of bis benzimidazo perylene (AzoPTCD) were fabricated using physical vapor deposition (PVD) technique. Thermal stability and integrity of the AzoPTCD PVD films during the fabrication (similar to 400 degrees C at 10(-6) Torr) were monitored by Raman scattering. Complementary thermogravimetric results showed that thermal degradation of AzoPTCD occurs at 675 degrees C. The growth of the PVD films was established through UV-vis absorption spectroscopy, and the surface morphology was surveyed by atomic force microscopy (AFM) as a function of the mass thickness. The AzoPTCD molecular organization in these PVD films was determined using the selection rules of infrared absorption spectroscopy (transmission and reflection-absorption modes). Despite the molecular packing, X-ray diffraction revealed that the PVD films are amorphous. Theoretical calculations (density functional theory, B3LYP) were used to assign the vibrational modes in the infrared and Raman spectra. Metallic nanostructures, able to sustain localized surface plasmons (LSP) were used to achieve surface-enhanced resonance Raman scattering (SERRS) and surface-enhanced fluorescence (SEF).

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O lactofen é um herbicida difeniléter recomendado para controlar plantas daninhas de folhas largas em campos de soja (Glycine max) e seu mecanismo de ação é a inibição da protoporfirinogênio-IX oxidase (Protox), que atua na biossíntese de clorofilas. Essa inibição resulta em um acúmulo de protoporfirina-IX, o que leva à produção de espécies reativas de oxigênio (ROS), causando estresse oxidativo. Conseqüentemente, podem ocorrer manchas, enrugamento e queima das folhas, o que leva à paralisação temporária do crescimento da cultura. Porém, o óxido nítrico (NO) atua como um antioxidante na eliminação direta das ROS. Assim, o objetivo deste trabalho foi verificar, por meio de avaliações fitométricas e bioquímicas, o efeito protetor do NO em plantas de soja tratadas com o herbicida lactofen. Plantas de soja foram pré-tratadas com diferentes doses de Nitroprussiato de Sódio (SNP), substância doadora de NO, e então pulverizadas com 168 g a.i. ha-1 lactofen. O pré-tratamento com SNP foi benéfico, pois o NO reduziu os sintomas de injúria causados pelo lactofen nos folíolos jovens e manteve baixos teores de açúcares solúveis. Porém, o NO proporcionou crescimento mais lento das plantas. Desta forma, posteriores estudos são necessários para elucidar os mecanismos de ação do NO na sinalização do estresse promovido pelo lactofen na cultura da soja.

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The epithelial principal cells are the predominant cell type of the epididymis. These cells have been shown to be both secretory and endocytic cells. The apical region of the cytoplasm of principal cells in the mongrel dog are located close to the cell apex and tubular lumen, and shown microvilli at the luminal border and present a endocytic apparatus, that consists of coated pits and vesicles, endosomes of varying size, multivesicular bodies, and lysosomes. The endosomes, multivesicular bodies and lysosomes contained the electron-dense patches. These results suggest that principal cells of the epididymis in the dog as possess a highly developed endocytic apparatus play a role in endocytosis. These cells function are similarly to the related in other mammals, in performing endocytosis.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Thin films of SrBi4Ti4O15 (SBTi), a prototype of the Bi-layered-ferroelectric oxide family, were obtained by a soft chemical method and crystallized in a domestic microwave oven. For comparison, films were also crystallized in a conventional method at 700 degrees C for 2 h. Structural and morphological characterization of the SBTi thin films were investigated by Xray diffraction (XRD) and atomic force microscopy (AFM), respectively. Using platinum coated silicon substrates, the ferroelectric properties of the films were determined. Remanent polarization P-r and a coercive field E-c values of 5.1 mu C/cm(2) and 135 kV/cm for the film thermally treated in the microwave oven and 5.4 mu C/cm(2) and 85 kv/cm for the film thermally treated in conventional furnace were found. The films thermally treated in the conventional furnace exhibited excellent fatigue-free characteristics up to 10(10) switching cycles indicating that SBTi thin films are a promising material for use in non-volatile memories. (C) 2007 Elsevier B.V. All rights reserved.

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This article reports a study of the thermal stability and morphological changes in tin oxide nanobelts grown in the orthorhombic SnO phase. The nanobelts were heat-treated in a differential scanning calorimetry (DSC) furnace at 800 degrees C for I It in argon, oxygen, or synthetic air atmospheres. The samples were then characterized by DSC, X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and high resolution field emission scanning electron microscopy (FE-SEM). The results confirmed that the orthorhombic SnO phase is thermodynamically unstable, causing the belts to transform into the SnO2 phase when heat-treated. During the phase transition, if oxygen is available in the furnace atmosphere, nanofibers grow at the edge of nanobelts at about 50 degrees of the belts' growth direction, while particles grow on the belt surface in the absence of oxygen. Although the decomposition process reduces the nanobelt cell volume by 22%, most belts remain monocrystalline after the heat treatment. The results confirm that phase transition is a decomposition process, which explains the morphological changes in the belts based on metallic tin generated in the process.

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Cellulose nanowhiskers were prepared by sulfuric acid hydrolysis from coconut husk fibers which had previously been submitted to a delignification process. The effects of preparation conditions on the thermal and morphological behavior of the nanocrystals were investigated. Cellulose nanowhisker suspensions were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and X-ray diffraction. Results showed that it was possible to obtain ultrathin cellulose nanowhiskers with diameters as low as 5 nm and aspect ratio of up to 60. A possible correlation between preparation conditions and particle size was not observed. Higher residual lignin content was found to increase thermal stability indicating that by controlling reaction conditions one can tailor the thermal properties of the nanowhiskers. Published by Elsevier Ltd.