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Riparian plants exert flow resistance and largely influence the flow structure, which affects erosion, deposition and transport processes of fine sediments. Predicting these vegetative effects is important for flood, sediment and nutrient management. However, predictions on the fate of sediments are complicated by uncertainties associated with the suitable parameterization of natural plants and the associated effects on the turbulent flow field and on the variables in the transport equations. The aim of this study is to quantify deposition and transport of fine sandy sediment in a partly vegetated channel under laboratory conditions. Care was taken to reproduce conditions typical of vegetated floodplain flows including dense flexible grassy understory as a starting point. The experiments were conducted in a flume that is specifically designed to recirculate fine sediment. We measured suspended sediment concentrations with optical turbidity sensors and determined patterns of net deposition over the vegetated parts of the cross section. The flow field was determined with acoustic Doppler velocimetry. Our investigations are intended to improve future predictions of fine sediment storage and transport in natural or constructed vegetated channels, and the first results reported herein were useful in designing further, on-going experiments with complex combinations of vegetation and channel geometry. Key words: sediment transport, suspended sediment, deposition, riparian vegetation, flow field.

Abstract Background Status epilepticus (SE) is proposed to lead to an age-dependent acute activation of a repertoire of inflammatory processes, which may contribute to neuronal damage in the hippocampus. The extent and temporal profiles of activation of these processes are well known in the adult brain, but less so in the developing brain. We have now further elucidated to what extent inflammation is activated by SE by investigating the acute expression of several cytokines and subacute glial reactivity in the postnatal rat hippocampus. Methods SE was induced by an intraperitoneal (i.p.) injection of kainic acid (KA) in 9- and 21-day-old (P9 and P21) rats. The mRNA expression of interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), matrix metalloproteinase-9 (MMP-9), glial-derived neurotrophic factor (GDNF), interferon gamma (IFN-γ), and transforming growth factor-beta 1 (TGF-β1) were measured from 4 h up to 3 days after KA injection with real-time quantitative PCR (qPCR). IL-1β protein expression was studied with ELISA, GFAP expression with western blotting, and microglial and astrocyte morphology with immunohistochemistry 3 days after SE. Results SE increased mRNA expression of IL-1β, TNF-α and IL-10 mRNA in hippocampus of both P9 and P21 rats, their induction being more rapid and pronounced in P21 than in P9 rats. MMP-9 expression was augmented similarly in both age groups and GDNF expression augmented only in P21 rats, whereas neither IFN-γ nor TGF-β1 expression was induced in either age group. Microglia and astrocytes exhibited activated morphology in the hippocampus of P21 rats, but not in P9 rats 3 d after SE. Microglial activation was most pronounced in the CA1 region and also detected in the basomedial amygdala. Conclusion Our results suggest that SE provokes an age-specific cytokine expression in the acute phase, and age-specific glial cell activation in the subacute phase as verified now in the postnatal rat hippocampus. In the juvenile hippocampus, transient increases in cytokine mRNA expression after SE, in contrast to prolonged glial reactivity and region-specific microglial activity after SE, suggest that the inflammatory response is changed from a fulminant and general initial phase to a more moderate and specific subacute response.