Anaerobic Thermophilic Colonization of Porous Support

Biofilm development in an open-pore sintered glass material (SIRAN) was studied using a laboratory-scale anaerobic fixed-film bioreactor under thermophilic conditions. The startup and performance of that bioreactor, operating on distillery waste water feed (vinasses), were also studied. Results obtained indicated that stepped organic loading during initial bioreactor start-up reduced the periods of adaptation in the colonization process and micro-organism attachment and biofilm formation was accelerated by the surface characteristics of the carrier. The results obtained by operating with stepped organic loading (& = 2.0 kg m–3 d–1 COD) over a period of 70 days suggest that a stable operation of the process (90% COD removal) and high density of biomass immobilized on the support (20 kgVSatt per m3 SIRAN) is achieved. Epifluorescence microscopy demonstrated that, initially, attached growth was developed in crevices, where biomass was protected from shear forces and, finally, SIRAN was completely covered and biofilm developed on the entire SIRAN particles

Influence of water content on the basic friction angle of porous limestones—experimental study using an automated tilting table

An accurate evaluation of the shear strength of discontinuities is frequently a key aspect for determining the safety of mining and civil engineering works and for solving instability issues at rock mass scale. This is usually done by using empirical shear strength criteria in which the basic friction angle (φb) is a relevant input parameter. Tilt testing is probably the most widespread method to obtain the φb due to its simplicity and low cost, but previous research has demonstrated that the results are strongly affected by several factors (e.g. surface finishing, cutting speed, specimen geometry, wear, time and rock type). In this connection, despite it is well known that water significantly reduces the mechanical properties of sedimentary rocks, very scarce research has focused on assessing the impact of the variations in water content on tilt test results. With the aim to fill this gap, saw-cut slabs of three limestone lithotypes were tilt tested in dry state, wet condition (fully water saturated, non-submerged samples) and under exposure to an environmental relative humidity (RH) of 90%. The results revealed that full water saturation caused moderate φb reductions in two lithotypes and a φb increase in one lithotype. This can be explained by their different microstructure and mineralogy, which makes that lubrication effect prevails over suction effect or vice versa. However, the exposure to a high RH environment did not cause significant φb variations. In addition, some important considerations related to tilt testing are provided and discussed, such as the intrinsic variability of the sliding angle (β) and the impact of multiple sliding on the same rock surfaces on β.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was partially supported by the Vicerrectorado de Investigación y Transferencia del Conocimiento of the University of Alicante through the projects UAUSTI18-21, UAUSTI20-20 and UAUSTI19-25

Steroid modulation of neurogenesis: Focus on radial glial cells in zebrafish

International audienc

Census of HII regions in NGC 6754 derived with MUSE: Constraints on the metal mixing scale

We present a study of the HII regions in the galaxy NGC 6754 from a two pointing mosaic comprising 197,637 individual spectra, using Integral Field Spectrocopy (IFS) recently acquired with the MUSE instrument during its Science Verification program. The data cover the entire galaxy out to ~2 effective radii (re ), sampling its morphological structures with unprecedented spatial resolution for a wide-field IFU. A complete census of the H ii regions limited by the atmospheric seeing conditions was derived, comprising 396 individual ionized sources. This is one of the largest and most complete catalogue of H ii regions with spectroscopic information in a single galaxy. We use this catalogue to derive the radial abundance gradient in this SBb galaxy, finding a negative gradient with a slope consistent with the characteristic value for disk galaxies recently reported. The large number of H ii regions allow us to estimate the typical mixing scale-length (rmix ~0.4 re ), which sets strong constraints on the proposed mechanisms for metal mixing in disk galaxies, like radial movements associated with bars and spiral arms, when comparing with simulations. We found evidence for an azimuthal variation of the oxygen abundance, that may be related with the radial migration. These results illustrate the unique capabilities of MUSE for the study of the enrichment mechanisms in Local Universe galaxies.Comment: 13 pages, 7 Figurs, accepted for publishing in A&

Association between urinary metabolic profile and the intestinal effects of cocoa in rats

The aim of this study was to elucidate the relationship between the urinary metabolic fingerprint and the effects of cocoa and cocoa fibre on body weight, hormone metabolism, intestinal immunity and microbiota composition. To this effect, Wistar rats were fed, for 3 weeks, a diet containing 10% cocoa (C10) or two other diets with same the proportion of fibres: one based on cocoa fibre (CF) and another containing inulin as a reference (REF) diet. The rats' 24 h urine samples were analysed by an untargeted 1H NMR spectroscopy-based metabonomic approach. Concentrations of faecal IgA and plasma metabolic hormones were also quantified. The C10 diet decreased the intestinal IgA, plasma glucagon-like peptide-1 and glucagon concentrations and increased ghrelin levels compared with those in the REF group. Clear differences were observed between the metabolic profiles from the C10 group and those from the CF group. Urine metabolites derived from cocoa correlated with the cocoa effects on body weight, immunity and the gut microbiota. Overall, cocoa intake alters the host and bacterial metabolism concerning energy and amino acid pathways, leading to a metabolic signature that can be used as a marker for consumption. This metabolic profile correlates with body weight, metabolic hormones, intestinal immunity and microbiota composition

Numerical simulation of thin layer coffee drying by control volumes

The thin layer drying model proposed by Sokhansanj and Bruce (1987) was implemented to model the drying process of parchment coffee beans. A computational model based on a control volume approach was developed to simulate the drying process of parchment coffee. A one dimensional transient analysis was implemented in the radial direction applied to a spherical coffee bean of equivalent radius. The results found that, even though the numerical value for the mass transfer coefficient is a small number (about of 10⁷ m/sec), moisture content predictions were sensitive to this value. The predicted drying curve compared favorably with published results