RESUMO
The carnivorous plant bladderwort exemplifies the use of accumulated elastic energy to power motion: respiration-driven pumps slowly load the walls of its suction traps with elastic energy (â¼1 h). During a feeding strike, this energy is released suddenly to accelerate water (â¼1 ms). However, due to the traps' small size and concomitant low Reynolds number, a significant fraction of the stored energy may be dissipated as viscous friction. Such losses and the mechanical reversibility of Stokes flow are thought to degrade the feeding success of other suction feeders in this size range, such as larval fish. In contrast, triggered bladderwort traps are generally successful. By mapping the energy budget of a bladderwort feeding strike, we illustrate how this smallest of suction feeders can perform like an adult fish.
Assuntos
Transferência de Energia/fisiologia , Cadeia Alimentar , Lamiales/fisiologia , Fenômenos Biomecânicos , TermodinâmicaRESUMO
A popular approach to attaining controlled drug delivery from polymer based systems involves the use of cross-linkers. In order to improve the properties of polymers specific to their applications, they can be modified by either physical cross-linkers (high pressure, irradiation) or chemical cross-linkers (glutaraldehyde, genipin). This chapter provides an insight into the different types and mechanisms of cross-linking. It reviews the existing drug delivery systems to understand the effects of cross-linking in them. The recent applications of cross-linked polymeric drug delivery and tissue engineering systems are also discussed.