997 resultados para super-heavy nuclei


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The possibility of using high-intensity laser-produced plasmas as a source of energetic ions for heavy ion accelerators is addressed. Experiments have shown that neon ions greater than 6 MeV can be produced from gas jet plasmas, and well-collimated proton beams greater than 20 MeV have been produced from high-intensity Laser solid interactions. The proton beams from the back of thin targets appear to be more collimated and reproducible than are high-energy ions generated in the ablated plasma at the front of the target and may be more suitable for ion injection applications. Lead ions have been produced at energies up to 430 MeV.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Lectins and adhesins are involved in bacterial adhesion to host tissues and mucus during early steps of infection. We report the characterization of BC2L-C, a soluble lectin from the opportunistic pathogen Burkholderia cenocepacia, which has two distinct domains with unique specificities and biological activities. The N-terminal domain is a novel TNF-alpha-like fucose-binding lectin, while the C-terminal part is similar to a superfamily of calcium-dependent bacterial lectins. The C-terminal domain displays specificity for mannose and L-glycero-D-manno-heptose. BC2L-C is therefore a superlectin that binds independently to mannose/heptose glycoconjugates and fucosylated human histo-blood group epitopes. The apo form of the C-terminal domain crystallized as a dimer, and calcium and mannose could be docked in the binding site. The whole lectin is hexameric and the overall structure, determined by electron microscopy and small angle X-ray scattering, reveals a flexible arrangement of three mannose/heptose-specific dimers flanked by two fucose-specific TNF-alpha-like trimers. We propose that BC2L-C binds to the bacterial surface in a mannose/heptose-dependent manner via the C-terminal domain. The TNF-alpha-like domain triggers IL-8 production in cultured airway epithelial cells in a carbohydrate-independent manner, and is therefore proposed to play a role in the dysregulated proinflammatory response observed in B. cenocepacia lung infections. The unique architecture of this newly recognized superlectin correlates with multiple functions including bacterial cell cross-linking, adhesion to human epithelia, and stimulation of inflammation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This special issue seeks to engage the term 'stewardship' and the practical and theoretical work around it, both of which are destined to remain items of unfinished business as governance struggles to keep up and connect with its fast moving technological and societal targets. While this special issue is testament to that observation, it also helps to foster much needed scholarly discussion and critique – and to ensure this field is not unwittingly formed and deployed by and as a legitimating support for governance, but rather opened up, elaborated and contested. The articles provide innovative insights and food for thought on the conception and legal-political practice and potential of stewardship and ‘super-stewardship’ in national, supranational and international settings.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introduces the articles in the special issue.