Theoretical study of the effects of modifying the structures of organic dyes based on N,N-alkylamine on their efficiencies as DSSC sensitizers.

In this work, we carried out a theoretical study in which DFT and TD-DFT calculations of a series of six new organic dyes that incorporate N,N-alkylamine as an electron donor and a cyanoacrylic acid group as an electron acceptor and anchoring group were performed. In each dye, the donor and the acceptor were bridged by six different π-conjugated spacers consisting of an auxiliary donor group (3,4-ethylenedioxythiophene, EDOT) or an auxiliary acceptor group (benzothiadiazole, BTZ or diketopyrrolopyrrole, DPP) that was linked to either thiophene or phenyl. EHOMO, ELUMO, Egap, λmax, Eex, the open-circuit photovoltage (Voc), the light-harvesting efficiency (LHE), and the free injection energy (ΔGinject) were calculated for all of the dyes to compare their photovoltaic performance. The effects of the incorporation of an additional acceptor group (DPP or BTZ) or an additional donor group (EDOT) into the π-bridge on the geometry, electronic structure, and photovoltaic performance of each designed dye were explored. The study shows that modifying the dye skeleton can greatly improve the performance of the dye and increase its power conversion efficiency. It also reveals that all of the studied dyes are promising candidates for an effective DSSC sensitizer, especially those that include the acceptor group DPP in the π-bridge.

Unexpected Fe local order in iron oxide coated nanocrystalline magnesium oxides with exceptional reactivities against environmental toxins.

Mg oxide nanoparticles are very reactive materials used to mitigate atmospheric pollution and to sequester polluting molecules. Using Fe K-edge XAFS, we have studied the structure of iron oxide-coated MgO nanoparticles before and after reaction with CCl4. Before reaction, the local structure around Fe is totally different from that in iron oxide coatings on SrO and CaO nanoparticles, although these coated materials were prepared in the same way. In SrO and CaO, the iron oxide coating has been shown to be well separated from the bulk of the nanoparticle, whereas in MgO, Fe was found to mix with MgO. After reaction with CCl4, Fe-Cl bonds can be detected when the coated nanoparticle is saturated. Such Fe-Cl EXAFS signals have not been observed in previously studied nanoparticles.

A simple in vitro test to evaluate biocompatibility of dialysis membranes.

As arachidonic acid metabolites are implicated in hypersensitivity reactions, we measured arachidonic acid metabolites of dialysed patient's granulocytes, preincubated with different dialysis membranes. Results indicate that cuprophan and cellulose acetate membranes partially inhibit in vitro production of 15-HETE and 5-HETE, whereas polyacrylonitrile membrane does not. This suggests that polyacrylonitrile is a more biocompatible membrane.

[Peritonitis in continuous ambulatory peritoneal dialysis: diagnosis and treatment]. / Les péritonites en dialyse péritonéale continue ambulatoire: diagnostic et traitement.

Several antibiotic regimens to treat CAPD related peritonitis have been published. Some of them do not have any severe side effect. But they are efficient in less than 2/3 of the cases. Other treatments (2 antibiotics, one of them is an aminoglycoside) are more frequently efficient, but they seem to have severe ototoxicity. We propose the use of cephalosporins and quinolones for first line treatment of CAPD peritonitis. This regimen seem highly efficient without severe side effect.