Caractéristiques pétrologiques et géochimiques des roches magmatiques d’El Aouana, NE algérien = Petrological and geochemical characteristics of the magmatic rocks from El Aouana, NE Algeria

The El Aouana igneous rocks are part of the Miocene magmatic suite that extends from Northern Tunisia to Morocco through the Algerian coast in the Maghrebin chain. These rocks are composed of volcanic (andesites and dacites) and subvolcanic (micodiorites and microgranodiorites) lithologies that intruded both the Cretaceous and Oligo-Miocene nappes, and the Miocene post-nappe sediments. The andesites are composed of plagioclase, amphibole and pyroxene phenocrysts that are set in a microlithic groundmass. The dacites are plagioclase-rich and rare, highly altered ferromagnesian minerals. The microdiorites and microgranodiorites are hornblende-bea- ring rocks with plagioclase, pyroxene and rare biotite phenocrysts that are set in a microcrystalline groundmass. Geochemical observations show that the rocks are calc-alkaline with I-type affinity. They are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) compared to high field strength elements (HFSE) and heavy rare earth elements (HREE). The negative Nb, P and Ti anomalies observed on the multi-element patterns are imprints of magmas originated from subduction zones. Field, petrological and geochemical investi- gations show that the El Aouana Miocene igneous rocks are emplaced in a post-collisionnal setting. These rocks show similarities with the metaluminous, post-collisionnel granitoids of north-eastern Algeria which are thought to have been derived from a metasomatized mantle source as a consequence of ‘slab break-off’ underneath the North African margin

Electrochemical Boron-Doped Diamond Film Microcells Micromachined with Femtosecond Laser: Application to the Determination of Water Framework Directive Metals

Planar electrochemical microcells were micromachined in a microcrystalline boron-doped diamond (BDD) thin layer using a femtosecond laser (Photo 1). The electrochemical performances of the new laser-machined BDD microcell were assessed by differential pulse anodic stripping voltammetry (DPASV) determinations, at nM level, of the four heavy metal ions of the European Water Framework Directive (WFD): Cd(II), Ni(II), Pb(II), Hg(II). The results are compared with those of previously published BDD electrodes [1]. The calculated detection limits are 0.4 nM, 6.8 nM and 5.5 nm 2.3 nM, and the linearities go up to 35nM, 97nM, 48nM and 5nM for respectively Cd(II), Ni(II) Pb(II) and Hg(II). The detection limits meet with the environmental quality standard of the WFD for three of the four metals. It was shown that the four heavy metals could be detected simultaneously, in the concentration ratio usually measured in sewage or runoff waters

Surface modification, strengthening effect and electrochemical comparative study of Zn-Al2O3-CeO3 and Zn-TiO2-CeO3 coating on mild steel

Surface enhancement of engineering materials is necessary for preventing service failure and corrosion attacks industrially. The surface modification, strengthening effect and electrochemical comparative study of Zn-Al2O3-CeO3 and Zn-TiO2-CeO3 coating on mild steel was investigated. Deposition was performed to obtain a better surface adherent coating using the electrodeposition technique. Co-deposition of mild steel resulted into surface modification attributes to the complex alloys that were developed. Films of mild steel were electrodeposited on zinc electrodes using the chloride bath solutions. The effect of deposition potentials was systematically studied using a focus ion beam scanning electron microscope (FIB-SEM) and an atomic force microscope (AFM) to observe the surface morphology, topography and the surface adherent properties of the coatings. The elemental composition and the phases evolved in composite coatings were measured by means of the energy dispersed spectrometer (EDS). The microhardness measurements and corrosion behaviours of the deposits were investigated. Weight loss measurement was conducted on the plated samples to observe the rate of corrosion and it was observed that there was severe corrosion on the controlled sample in comparison to the plated samples and that Zn-TiO2-CeO3 resisted more corrosion attacks

A Novel Conductometric Urea Biosensor with Improved Analytical Characteristic Based on Recombinant Urease Adsorbed on Nanoparticle of Silicalite

Development of a conductometric biosensor for the urea detection has been reported. It was created using a non-typical method of the recombinant urease immobilization via adsorption on nanoporous particles of silicalite. It should be noted that this biosensor has a number of advantages, such as simple and fast performance, the absence of toxic compounds during biosensor preparation, and high reproducibility (RSD = 5.1 %). The linear range of urea determination by using the biosensor was 0.05–15 mM, and a lower limit of urea detection was 20 μM. The bioselective element was found to be stable for 19 days. The characteristics of recombinant urease-based biomembranes, such as dependence of responses on the protein and ion concentrations, were investigated. It is shown that the developed biosensor can be successfully used for the urea analysis during renal dialysis

Machining of tough polyethylene pipe material: surface roughness and cutting temperature optimization

International audienc

Chimioradiothérapie des cancers du rectum

International audienceThree randomised studies have recently indicated preoperative chemoradiotherapy as a standard treatment for patients with T3-T4 B381 B393 resectable rectal cancer. This new approach improves local control and has local failure rates ranging from 6 to 8%. New clinical research should focus on effectively treating microscopic disease and refining the indications for preoperative chemoradiotherapy

On the use of the FluoroProbe®, a phytoplankton quantification method based on fluorescence excitation spectra for large-scale surveys of lakes and reservoirs

Although microscope analysis is very useful for studying phytoplankton communitycomposition, it does not allow for high frequency (spatial and/or temporal) data acquisi-tion. In an attempt to overcome this issue, fluorescence-based approaches that useselective excitation of pigment antennae have spread rapidly. However, the ability of spectral fluorescence to provide accurate estimates of phytoplankton biomass andcomposition is still debated, and only a few datasets have been tested to date.In this study, we sampled of a wide range of water bodies (n¼50) in the Ile-de-Franceregion (North Central France). We used the resulting extensive dataset to assess theability of the bbe-Moldaenke FluoroProbe II (FP) to estimate phytoplankton communitycomposition in lakes and reservoirs.We demonstrated that FP data yields better estimates of total phytoplankton biovolumethan do spectrophotometric chlorophyllameasures and that FP data can be further cor-rected using the average chlorophyllato biovolume ratio among phytoplankton groups.Overall, group-specific relationships between FP and biovolume data were consistent.However, we identified a number of cases where caution is required. We found thatEuglenophytes are expected to depart from the global FPvs.biovolume relationship of the‘green’ group due to varying Fv/Fm and pigment content in response to environmentalconditions (photoautotrophicvs.photoheterotrophic growth). Then, it appears necessaryto consider the composition of the Chromophytes community in order to obtain a goodagreement between both biomass estimation methods. Finally, we confirmed the misat-tribution toward the ‘red’ group of phycoerythrin-containing cyanobacteria and theoccurrence of a strong scattering in the relationship between the FPvs.biovolume of the‘blue’ group that can be partly attributed to the occurrence of large colony-forming cya-nobacteria (e.g.,Microcystisspp,Aphanizomenon flos-aquae).We propose correcting procedures to improve the quality of data obtained from spectral fluorescence tools in the context of large-scale sampling of lakes and reservoirs