Highly efficient, long life, reusable and robust photosynthetic hybrid core-shell beads for the sustainable production of high value compounds.

An efficient one-step process to synthesize highly porous (Ca-alginate-SiO2-polycation) shell: (Na-alginate-SiO2) core hybrid beads for cell encapsulation, yielding a reusable long-life photosynthetically active material for a sustainable manufacture of high-value metabolites is presented. Bead formation is based on crosslinking of an alginate biopolymer and mineralisation of silicic acid in combination with a coacervation process between a polycation and the silica sol, forming a semi-permeable external membrane. The excellent mechanical strength and durability of the monodispersed beads and the control of their porosity and textural properties is achieved by tailoring the silica and alginate loading, polycation concentration and incubation time during coacervation.

Influence of back mixing on the convective drying of residual sludges in a fixed bed.

The influence of a backmixing operation on the convective belt drying of two wastewater sludges was studied. The expansion of the sludge extrudates bed due to increasing additions of dry product was quantified by using X-ray tomography. This non-invasive technique was used to determine the bed porosity and the total exchange area available for heat and mass transfers, for increasing levels of backmixing.

Non-destructive characterization of deer (Cervus Elaphus) antlers by X-ray microtomography coupled with image analysis.

X-ray microtomography coupled with image analysis was tested as a non-destructive alternative method for the textural characterization of the trabecular part of deer antlers (Cervus Elaphus). As gas adsorption and mercury intrusion cannot be applied on this soft and spongy material, its pore texture was, up to now, determined from histological sections that give only two-dimensional information. In this work, X-ray microtomography is used to scan entire or half pieces of antlers and three-dimensional image analysis is performed in order to assess the differences between samples collected at various antler locations.

Image analysis of X-ray microtomograms of soft materials during convective drying: 3D measurements.

Drying dewatered sludge leads to a complex three-dimensional porous structure. Moreover, this operation is dependent on the way the material is processed. In this study, textural changes of sludge extrudates submitted to convective drying are followed by a 3D image analysis of reconstructed X-ray microtomograms.

Wastewater sludge convective drying: influence of sludge origin.

This paper deals with thermal drying of wastewater sludges, whose management will become crucial in the forthcoming years. Sludges collected after mechanical dewatering in 5 different WWTPs are submitted to the same convective drying treatment in order to try finding some relations between the drying behaviours, the type of effluent and wastewater treatments. Results show dearly sludge drying remains a particularly complex operation because sludges may exhibit very different behaviours, both from kinetic and texture points of view.

Image analysis of X-ray microtomograms of soft materials during convective drying.

X-ray microtomography is used to explore the textural evolution that soft materials undergo during a drying treatment. An original image processing algorithm is applied to vertical projections and reconstructed cross-section images in order to quantify the texture at different stages of drying. Measurements are performed both on grey-level and on binary images.

[Risk of contamination by hepatitis C of endoscopes utilized in gastroenterology hospital service].

Unlabelled: Transmission of hepatitis C virus by gastrointestinal endoscopy has been suggested especially therapeutic procedures. The aim of this study was to investigate the frequency of contamination of the endoscopes by hepatitis C virus and to assess the efficacy of a semi-automatic disinfection procedure.

Methods: In 19 patients with chronic replicative hepatitis C, upper gastrointestinal endoscopy with different invasive procedures was performed.

Saturation of penicillin-binding protein 1 by beta-lactam antibiotics in growing cells of Bacillus licheniformis.

With the help of a new highly sensitive method allowing the quantification of free penicillin-binding proteins (PBPs) and of an integrated mathematical model, the progressive saturation of PBP1 by various beta-lactam antibiotics in growing cells of Bacillus licheniformis was studied. Although the results confirmed PBP1 as a major lethal target for these compounds, they also underlined several weaknesses in our present understanding of this phenomenon. In growing cells, but not in resting cells, the penicillin target(s) appeared to be somewhat protected from the action of the inactivators.

Quantitative relationship between sensitivity to beta-lactam antibiotics and beta-lactamase production in gram-negative bacteria--II. Non-steady-state treatment and progress curves.

A non-steady-state model is discussed for the study of the interplay between beta-lactamase activity and outer membrane permeability with slowly hydrolysed beta-lactams. The analysis shows: (1) that the simple, steady-state model presented in the accompanying paper remains valid as long as kcat (i.e.

Structure-activity relationships in the beta-lactam family: an impossible dream.

The difficulty of establishing structure-activity relationships in the beta-lactam family of antibiotics stems from the fact that: (1) The targets in various bacteria exhibit widely different sensitivities. (2) Some bacteria produce beta-lactamases, enzymes capable of destroying the antibiotics. The rates of the reactions with the beta-lactamases and the target enzymes are not necessarily related.