Viscous and filamentous bulking in activated sludge: Rheological and hydrodynamic modelling based on experimental data.

Although achieving good activated sludge settleability is a key requirement for meeting effluent quality criteria, wastewater treatment plants often face undesired floc structure changes. Filamentous bulking has widely been studied, however, viscous sludge formation much less investigated so far. Our main goal was to find relationship between sludge floc structure and related rheological properties, moreover, to estimate pressure loss in pipe networks through hydrodynamic modelling of the non-Newtonian flows in case of well settling (ideal-like), viscous and filamentous sludge. Severe viscous and filamentous kinds of bulking were generated separately in continuous-flow lab-scale systems initially seeded with the same reference (ideal-like) biomass and the entire evolution of viscous and filamentous bulking was monitored. The results suggested correlation between the rheological properties and the floc structure transformations, and showed the most appropriate fit for the Herschel-Bulkley model (vs. Power-law and Bingham). Validated computational fluid dynamics studies estimated the pipe pressure loss in a wide Reynolds number range for the initial well settling (reference) and the final viscous and filamentous sludge as well. A practical standard modelling protocol was developed for improving energy efficiency of sludge pumping in different floc structure scenarios.

Altered mitochondrial response to activation of T-cells in neonate.

UNLABELLED: Mitochondrial functions have a major impact on T-cell functionality. In this study we characterized whether mitochondrial function in the neonatal T-cells differs from that in the adult T-cells during short T-cell activation. METHODS: We used flow cytometry methods to test mitochondrial mass and to monitor mitochondrial Ca²âº levels, mitochondrial potential and superoxide generation in parallel with cytoplasmic Ca²âº levels during phythohaemagglutinine-induced activation of CD4+ and CD8+ T-cells of 12 term neonates and 11 healthy adults. RESULTS: Baseline mitochondrial mass of CD4+ and CD8+ cells was lower in the neonate than in the adult. In comparison with the adult, neonatal resting CD4+ T-cells had lower cytoplasmic Ca²âº levels and this was associated with normal activation induced Ca²âº-response. During short-term activation cytoplasmic Ca²âº-response was lower in neonatal than in adult CD8+ T-cells. Mitochondrial Ca²âº uptake was increased in CD4+ neonatal T cells while it decreased in CD8+ T-cells. Mitochondrial depolarization was increased in CD4+ and decreased in CD8+ neonatal T-cells compared to adults. Superoxide generation was higher and equal in neonatal CD4+ and CD8+ cells, respectively, compared to the adult ones. CONCLUSION: Our data suggest that neonatal T-cells exhibit marked differences in mitochondrial function and superoxide generation compared to adult T-cells.

Maternal cytokine balance on the third postpartum day is not affected by the mode of delivery after healthy pregnancies.

Previous reports have suggested that delivery is associated with the induction of inflammatory cytokines. The present study was designed to investigate whether increased cytokine production was present on postpartum day 3 after a normal pregnancy and whether any changes were associated with the mode of delivery. In total, 33 pregnant women were enrolled; 18 delivered vaginally and 15 underwent an elective caesarean section (C-section). The levels of 17 cytokines and growth hormones were measured at the beginning of delivery or before anaesthesia and on postpartum day 3. While interleukin (IL)-6 and IL-8 levels decreased significantly postpartum, other cytokine concentrations were comparable before and after delivery. Only IL-7 levels were significantly increased in the C-section patients compared with the vaginal birth patients postpartum. In conclusion, there was no risk of a prolonged maternal inflammatory reaction after an uncomplicated vaginal birth or elective C-section, so it is probably not necessary to consider this as an issue when making a decision on the mode of delivery following uncomplicated pregnancy.