Combining pretreatments and co-fermentation as successful approach to improve biohydrogen production from dairy cow manure.

The present paper is focused on enhancing the production of biohydrogen (bioH2) from dairy cow manure (DCM) through dark fermentation (DF). Two enhancement production strategies have been tested: i) the combination of H2O2 with sonification as pretreatment and ii) the co-fermentation with cheese whey as co-substrate. Concerning the pretreatment, the best combination was investigated according to the response surface methodology (RSM) by varying H2O2 dosage between 0.0015 and 0.06 g/gTS and ultrasonic specific energy input (USEI) between 35.48 and 1419.36 J/gTS. The increase of carbohydrates concentration was used as target parameter. Results showed that the combination of 0.06 g/gTS of H2O2 with 1419.36 J/gTS of USEI maximized the concentration of carbohydrates. The optimized conditions were used to pretreat the substrate prior conducting DF tests. The use of pretreatment resulted in obtaining a cumulative bioH2 volume of 51.25 mL/L and enhanced the bioH2 production by 125% compared to the control test conducted using raw DCM. Moreover, the second strategy, i.e. co-fermentation with cheese whey (20% v/v) as co-substrate ended up to enhancing the DF performance as the bioH2 production reached a value of 334.90 mL/L with an increase of 1372% compared to the control DF test. To further improve the process, dark fermentation effluents (DFEs) were valorized via photo fermentation (PF), obtaining an additional hydrogen production aliquot.

Mechanisms of adipose tissue extracellular matrix alterations in an in vitro model of adipocytes hypoxia and aging.

Fibrosis has been considered as a hallmark of dysfunctional adipose tissue (AT), however the role and mechanisms of fibrosis in the age related AT dysfunction are not yet well characterized. The aim of the study was to investigate the mechanisms of extracellular matrix (ECM) alterations and the role of caveolins, using an in vitro model of adipocyte aging and hypoxia. Hypoxic adipocytes, but also aged adipocytes, were characterized by a significant increase in gene expression of pro-inflammatory cytokines and ECM components. Immunofluorescence analysis confirmed an increase in collagen VI-A3 in hypoxic and also in aged adipocytes. However aged adipocytes were characterized by only a slight increase in HIF1α immunofluorescence and by a more relevant increase in senescence compared to hypoxic and mature adipocytes, with an increase in p-53 protein and a decrease in SIRT 1 protein. Immunofluorescence and western blot analysis revealed a significant decrease in caveolin-1 expression in hypoxic adipocytes and even more in aged adipocytes. In conclusions, aging adipocytes are associated to alteration of ECM and fibrosis, by modulation of the caveolins through complex mechanisms where inflammation, hypoxia and cellular senescence are coexisting.

Shear viscosity of strongly coupled N = 4 supersymmetric Yang-Mills plasma.

Using the anti-de Sitter/conformal field theory correspondence, we relate the shear viscosity eta of the finite-temperature N = 4 supersymmetric Yang-Mills theory in the large N, strong-coupling regime with the absorption cross section of low-energy gravitons by a near-extremal black three-brane. We show that in the limit of zero frequency this cross section coincides with the area of the horizon. From this result we find eta = pi / 8N(2)T3. We conjecture that for finite 't Hooft coupling g(2)(YM)N the shear viscosity is eta = f(g(2)(YM)N)N2T3, where f(x) is a monotonic function that decreases from O(x(-2)ln(-1)(1/x)) at small x to pi/8 when x-->infinity.