Influ?ncia das tens?es induzidas por realces em lavra por subn?veis nas condi??es de estabilidade de galerias de desenvolvimento em minas subterr?neas.

This work aims to investigate the influence of induced stresses by sublevel stopes in development excavations, which are excavated to access these stopes. Parametric studies changing the position of development openings in relation to stopes were performed in order to evaluate the stability conditions of these openings. Numerical modeling using finite element method was applied to the simulations. An elastic behavior of the rock mass was assumed to allow the simulation of a lot of different opening locations. The results have showed distinct scenarios. Some cases of global collapse were found as well as some situations where the integrity of the openings could be kept. Therefore, the most favorable situations were chosen to perform a plastic analysis in order to have a better knowledge of opening stability conditions. The geometry of the excavations from Caraiba Mining Company, which extracts copper from an underground mine in Brazil, was used in these analyses to illustrate a real situation where many failure problems in these development openings were observed.Este trabalho tem por objetivo analisar a influ?ncia das tens?es induzidas por realces em lavra por subn?vel nas galerias de desenvolvimento, que s?o escavadas para acesso a esses realces. Foram feitos estudos param?tricos variando a posi??o das galerias em rela??o aos realces para avaliar as condi??es de estabilidade dessas galerias, utilizando modelagem num?rica atrav?s do m?todo dos elementos finitos. Um comportamento el?stico para o maci?o rochoso foi assumido para permitir a simula??o de v?rias posi??es para as galerias de acesso. Os resultados mostraram cen?rios distintos. Alguns casos de colapso global das galerias, bem como situa??es onde a integridade dessas aberturas pode ser mantida. Como consequ?ncia, nas situa??es mais favor?veis foram feitas an?lises pl?sticas de modo a obter um melhor conhecimento acerca das condi??es de estabilidade dessas galerias. A geometria das escava??es da Mina Cara?ba, que extrai cobre em mina subterr?nea no Brasil, foi utilizada para ilustrar uma situa??o real, onde muitos problemas de ruptura nas galerias de acesso aos realces foram observados

Zika Virus Infects, Activates, and Crosses Brain Microvascular Endothelial Cells, without Barrier Disruption

Zika virus (ZIKV) has been associated to central nervous system (CNS) harm, and virus was detected in the brain and cerebrospinal fluids of microcephaly and meningoencephalitis cases. However, the mechanism by which the virus reaches the CNS is unclear. Here, we addressed the effects of ZIKV replication in human brain microvascular endothelial cells (HBMECs), as an in vitro model of blood brain barrier (BBB), and evaluated virus extravasation and BBB integrity in an in vivo mouse experimental model. HBMECs were productively infected by African and Brazilian ZIKV strains (ZIKVMR766 and ZIKVPE243), which induce increased production of type I and type III IFN, inflammatory cytokines and chemokines. Infection with ZIKVMR766 promoted earlier cellular death, in comparison to ZIKVPE243, but infection with either strain did not result in enhanced endothelial permeability. Despite the maintenance of endothelial integrity, infectious virus particles crossed the monolayer by endocytosis/exocytosis-dependent replication pathway or by transcytosis. Remarkably, both viruses' strains infected IFNAR deficient mice, with high viral load being detected in the brains, without BBB disruption, which was only detected at later time points after infection. These data suggest that ZIKV infects and activates endothelial cells, and might reach the CNS through basolateral release, transcytosis or transinfection processes. These findings further improve the current knowledge regarding ZIKV dissemination pathways

Micropropagação do abacaxizeiro ornamental Protocol for in vitromicropropagation of ornamental pineapple

O Ananas comosus var. erectifolius, cultivar de abacaxi ornamental, tem apresentado grande interesse para paisagistas e floricultores do Brasil e do exterior, por ser uma planta ornamental tropical, exótica e rústica. A produção de plantas ornamentais a partir de técnicas de cultura de tecidos apresenta-se como uma alternativa viável para a obtenção de um grande número de plantas com qualidade genética e fitossanitária, em um curto espaço de tempo, suprindo, assim, a necessidade do mercado na aquisição de mudas com qualidade comprovada. Estudou-se a influência das concentrações de BAP (0; 0,5; 1,0 e 1,5 mg L-1) e ANA (0,0; 0,12; 0,24; 0,48 mg L-1) no meio de cultura MS com 0; 2,5; 5,0; e 7,5 g L-1 de ágar, visando estabelecer um protocolo para multiplicação e enraizamento in vitro de brotos de abacaxizeiro ornamental. Brotações com 1,5 &plusmn; 0,5 cm, já estabelecidas in vitro, oriundas das gemas da coroa do fruto do abacaxizeiro ornamental, foram inoculados assepticamente nos frascos. Após inoculados, os explantes foram mantidos em sala de crescimento com luminosidade em torno de 35 ìmol m-2 s-1, 26&plusmn;1ºC e fotoperíodo de 16 horas. Após 45 dias observou-se que a multiplicação in vitrodo abacaxi ornamental é viável em meio MS líquido acrescido de BAP 1,5 mg L-1 e o enraizamento também em meio MS líquido, na ausência de reguladores de crescimento.<br>The Ananas comosus var. erectifoliusis an ornamental pineapple cultivar which greatly interests Brazilians and foreign landscapers and flower producers for being an exotic and rustic tropical ornamental plant. The market demand for high quality of cuttings requires efficient methods of propagation and in this context the tissue culture stands out as a viable alternative to obtain plants with genetic and phytossanitary quality in a short time. In the present work we studied the influence of concentrations of BAP (0; 0.5; 1.0; 1.5 mg L-1) and NAA (0; 0.12; 0.24; 0.48 mg L-1) in the MS medium culture within 0; 2.5; 5.0; 7.5 g L-1 of agar, in order to establish an invitro protocol for multiplication and rooting of ornamental pineapple. Plantlets with 1.5&plusmn;0.5 cm already established in vitro, extracted from buds of ornamental pineapple fruits crown were inoculated aseptically in flasks. After inoculation the plantlets were kept in a growth room at 26&plusmn;1ºC, 35 ìmol m-2 s-1 irradiance and a 16-hour photoperiod. After 45 days we observed that the multiplication of ornamental pineapple is viable at liquid MS medium with BAP 1.5 mg L-1 and the rooting is also increased in liquid MS medium in absence of growth regulators