Influência da adubação nitrogenada e potássica na podridão de colmo do milho por antracnose (Colletotrichum graminicola) em duas cultivares de milho

Trabalho apresentado no 42º Congresso Brasileiro de Fitopatologia, 2009, Rio de Janeiro, RJ

Importância da adubação nitrogenada e potássica na incidência de colmos podres por antracnose (Colletotrichum graminicola) e a sua relação com o peso de grãos em duas cultivares de milho.

Trabalho apresentado no 42º Congresso Brasileiro de Fitopatologia, 2009, Rio de Janeiro, RJ

Hyaluronan density influences adhesion, morphology and migration of cancer cells

Hyaluronan (HA) is a linear non-sulfated glycosaminoglycan present in the extracellular matrix and known to modulate cell-cell and cell-ECM interactions. In cancer, the synthesis, degradation and signaling of HA is altered. For instance, its main receptor, CD44, is overexpressed in several types of cancer and has been correlated with disease progression through cancer cell proliferation, migration and chemoresistance. Herein, we investigated the behavior of breast cancer cells with different CD44 expression and invasion profile on HA density gradients. These gradients were achieved by deposition of colloidal gold (Au) on amino-functionalized surfaces at different ionic strengths and following binding of end-on thiol modified HA on the Au. At low HA density, small number of adherent round cells were found for all studied cell lines. Cells adherent to the areas with high HA density presented a spindle-like morphology. The differences were more pronounced for cells overexpressing CD44. These cells also form long filopodia when adhered on areas with middle and high HA density. Of note, colocalization of CD44 and actin was observed at the filopodias edges. Cell motility was also affected by the gradient – at low densities cells presented higher motility, which decreased with the increase of HA density. Besides this common trend, we observed differences among the studied cells. CD44 cells had shorter persistent length displacement than CD44 and CD44cells. Upon CD44 blockage, all types of cells (CD44++, CD44+, and CD44-) behave similarly . These results suggest that cells recognize HA gradients through CD44 receptors and that the HA density can be used to sort cells with different expression of this receptor.info:eu-repo/semantics/publishedVersio

An embedded crack model for the simulation of the complex interactions in fibre reinforced concrete

There are several benefits of introducing steel fibres in reinforced concrete. They can improve the structural ductility, reduce the permeability, and provide more resistance to cracking caused by loading and shrinkage. Steel fibres are mainly activated when they are crossed by active cracks in what is known by the bridging effect. They are mostly inactive otherwise. With the progress of damage, the fibres can be pulled out or fail, in which case the bond with the cementitious matrix is a critical factor for accurate simulations. Although existing models that are able to simulate fibres as discrete elements can achieve realistic predictions, difficulties are found in the generation of complex meshes with numerous randomly-oriented fibres, namely due to the requirement of excessive degrees of freedom and long computational times. The formulation herein proposed, embeds both discrete fibres and cracks within the finite elements, while accounting for the main features of the fibre behaviour, including the main effects such as the bond between fibre and cementitious material and snubbing. It should be highlighted that the fibre behaviour is modelled without the need for additional degrees of freedom. An advanced constitutive behaviour law is implemented that accounts for the changes depending on the inclination angle of the fibre relative to the crack and its embedment length. For fracture simulation, the model uses the Discrete Strong Discontinuous Approach (DSDA), where the jumps related to the opening of the cracks are transmitted to the parent element as a rigid body motion. Several numerical tests are used to assess the performance of the numerical technique, which include comparison with other formulations and experimental data

Composição corporal de búfalos Murrah.

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Regeneração dos acessos do BAG de algodão a partir de embriões zigóticos 2005.

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