Suchergebnisse

The end of the twentieth century wars initiated a paradigm shift. Conflicts that emerged at the end of the last century and developed in the early 21st century revealed new aspects of the armed struggle. The classic perception of war has been blurred. In place of the bipolar symmetry appeared asymmetric threats. The former state monopoly on the use of force was lost. Some new members of armed conflict appeared, traditional battlefield setting disappeared and progressive imbalance between the parties for the disposition of potential violence leads to inequality and instability in the world. Asymmetry became a main factor in determining the image of modern warfare.

Abstract
The ability of bacteria to colonize and grow on different surfaces is an essential process for biofilm development. Here, we report the use of synthetic hydrogels with tunable stiffness and porosity to assess physical effects of the substrate on biofilm development. Using time-lapse microscopy to track the growth of expanding Serratia marcescens colonies, we find that biofilm colony growth can increase with increasing substrate stiffness, unlike what is found on traditional agar substrates. Using traction force microscopy-based techniques, we find that biofilms exert transient stresses correlated over length scales much larger than a single bacterium, and that the magnitude of these forces also increases with increasing substrate stiffness. Our results are consistent with a model of biofilm development in which the interplay between osmotic pressure arising from the biofilm and the poroelastic response of the underlying substrate controls biofilm growth and morphology.