Synthesis and characterization of homo- and heterobimetallic niobium(v) and tantalum(v) peroxo-polyaminocarboxylato complexes and their use as single or multiple molecular precursors for Nb-Ta mixed oxides

New water-soluble bimetallic peroxo complexes of niobium(V) and/or tantalum(V) with high-denticity polyaminocarboxylate ligands have been prepared, characterized from the spectroscopic point of view, and used Lis molecular precursors for Nb-Ta mixed oxides. Four new homobimetallic complexes, (gu)(3)[Nb-2(O-2)(4)(dtpaO(3))]center dot 3H(2)O 1, (gu)(3)[Ta-2(O-2)(4)(dtpaO(3))]center dot 5H(2)O 2, (gu)(3)[Nb-2(O-2)(4) (HtthaO(4))]center dot 2H(2)O 4 and (gu)(3)[Ta-2(O-2)(4)(HtthaO(4))]center dot 3H(2)O 5 and the corresponding heterometallic complexes, (gu)(3)[NbTa(O-2)(4) (dtpaO(3))]center dot 2.5H(2)O 3 and (gu)(3)[NbTa(O-2)(4)(HtthaO4())]center dot 2H(2)O 6 have been obtained. In these compounds, the in situ oxidation of the nitrogen atoms of the PAC ligands into N-oxide groups has been evidenced by IR spectroscopy and mass spectrometry. The thermal treatment of the homonuclear complexes in air at 700 or 800 degrees C, depending on the Ta content, provided Nb2O5 or Ta2O5 while the heteronuclear Compounds led to the solid solution TaNbO5. BET and SEM measurements have been carried out and comparison of the morphology of the samples prepared from homo- and heterometallic precursors is discussed. (c) 2005 Elsevier Inc. All rights reserved

Nb-Ta, Nb-Mo and Nb-V oxides prepared from hybrid organic-inorganic precursors

New hybrid organic-inorganic materials based on group 5 elements and a well-defined polymeric matrix have been prepared and used as precursors for Nb-Ta and Nb-Mo mixed oxides. In this non-conventional but easily accessible route to multimetallic oxides, a copolymer of N,N-diallyl-N-hexylamine and maleic acid was synthesised and used as matrix to stabilise inorganic species generated in solution from (NH4)(6)Mo7O24-4H(2)O, NH4VO3, (gu)(3)[Nb(O-2)(4)] and (gu)(3)[Ta(O-2)(4)]. Solid-state studies indicate that the homogeneity of the blends can be kept up to about 0.5 mol Nb-v and Ta-v and 0.25 mol V-v per mol of repeat units of the copolymer. The calcination conditions of these homogeneous hybrid precursors were optimised to produce Nb-Mo, Nb-Ta and Nb-V oxides. While the thermal treatment of the Nb-V hybrid blends led only to a mixture of different phases, the characterisation of the final phases by X-ray diffraction (XRD) proved the formation of pure Nb2MO3O14 and showed that Nb-Ta oxides could be synthesised as single phases corresponding to a continuous series of solid solutions. (c) 2007 Elsevier Inc. All rights reserved

Spectroscopic and structural characterizations of water-soluble peroxo complexes of niobium(V) with N-containing heterocyclic ligands

New water-soluble heteroleptic peroxo complexes of niobium(V) have been prepared with N-containing heterocyclic ligands. The compounds correspond to the general formula (gu)(x)[Nb(O-2)(3)(L)]center dot nH(2)O (gu = guanidinium). Three different ligands (L) have been used: picolinic acid (Hpic), picolinic acid N-oxide (HpicO) and pyrazine 2,5-dicarboxylic acid (2,5-H(2)pzdc). The Nb-V complexes have been characterized on the basis of elemental and thermal analysis as well as by IR and ESI-rnass spectrometry. The crystal structure of the peroxo complex with the picolinato N-oxide ligand, (gu)(2)[Nb(O-2)(3)(picO)] (II) has been determined, showing an eightfold-coordinated Nb atom surrounded by three peroxide groups and a picO ligand bound in a bidentate mode via the carboxylato and the N-oxide groups. The coordination polyhedron around the metal is a triangular dodecahedron. (c) 2005 Elsevier B.V. All rights reserved

In het teken van identiteit. Taal en cultuur van de Nederlanden

In deze bundel brengen naaste en verre collega’s van Prof. Ludo Beheydt een hulde aan zijn rijkgevulde academische carrière als hoogleraar Nederlandse taal en cultuur aan de Université catholique de Louvain. Zes van zijn eerder gepubliceerde artikelen vormen de leidraad van de bundel. Ze weerspiegelen de brede interesse die Ludo Beheydt altijd heeft gekoesterd voor de verschillende uithoeken van de Nederlandse taal, in het bijzonder taal(kunde), taalverwerving, cultuur(kunde) en identiteit. De contribuanten werd gevraagd om met een van de geselecteerde artikelen in discussie te gaan. Dit leidt tot een waaier van diverse bijdragen waarin de Nederlandse taal en cultuur centraal staan

Asymptomatic left circumflex artery stenosis is associated with higher arrhythmia recurrence after persistent atrial fibrillation ablation

Background: The pathophysiology of persistent atrial fibrillation (AF) remains unclear. While several studies have demonstrated an association between myocardial infarction and atrial fibrillation, the role of stable coronary artery disease (CAD) is still unknown. As a result, we aimed to assess the association between CAD obstruction and AF recurrence after persistent AF ablation in patients with no history of CAD. Materials and methods: This observational retrospective study included consecutive patients who underwent routine preprocedural cardiac computed tomography (CCT) before persistent AF ablation between September 2015 and June 2018 in 5 European University Hospitals. Exclusion criteria were CAD or coronary revascularization previously known or during follow-up. Obstructive CAD was defined as luminal stenosis ≥ 50%. Results: All in all, 496 patients (mean age 61.8 ± 10.0 years, 76.2% males) were included. CHA2DS2-VASc score was 0 or 1 in 225 (36.3%) patients. Obstructive CAD was present in 86 (17.4%) patients. During the follow-up (24 ± 19 months), 207 (41.7%) patients had AF recurrence. The recurrence rate was not different between patients with and without obstructive CAD (43.0% vs. 41.5%, respectively; P = 0.79). When considering the location of the stenosis, the recurrence rate was higher in the case of left circumflex obstruction: 56% vs. 32% at 2 years (log-rank P ≤ 0.01). After Cox multivariate analysis, circumflex artery obstruction (HR 2.32; 95% CI 1.36-3.98; P < 0.01) was independently associated with AF recurrence. Conclusion: Circumflex artery obstruction detected with CCT was independently associated with 2-fold increase in the risk of AF recurrence after persistent AF ablation. Further research is necessary to evaluate this pathophysiological relationship

Persistent headaches one year after bacterial meningitis: prevalence, determinants and impact on quality of life

International audienceBackground: Little is known on headaches long-term persistence after bacterial meningitis and on their impact on patients' quality of life.Methods: In an ancillary study of the French national prospective cohort of community-acquired bacterial meningitis in adults (COMBAT) conducted between February 2013 and July 2015, we collected self-reported headaches before, at onset, and 12 months (M12) after meningitis. Determinants of persistent headache (PH) at M12, their association with M12 quality of life (SF 12), depression (Center for Epidemiologic Studies Depression Scale) and neuro-functional disability were analysed.Results: Among the 277 alive patients at M12 87/274 (31.8%), 213/271 (78.6%) and 86/277 (31.0%) reported headaches before, at the onset, and at M12, respectively. In multivariate analysis, female sex (OR: 2.75 [1.54-4.90]; p < 0.001), pre-existing headaches before meningitis (OR: 2.38 [1.32-4.30]; p < 0.01), higher neutrophilic polynuclei percentage in the CSF of the initial lumbar puncture (OR: 1.02 [1.00-1.04]; p < 0.05), and brain abscess during the initial hospitalisation (OR: 8.32 [1.97-35.16]; p < 0.01) were associated with M12 persistent headaches. Neither the responsible microorganism, nor the corticoids use were associated with M12 persistent headaches. M12 neuro-functional disability (altered Glasgow Outcome Scale; p < 0.01), M12 physical handicap (altered modified Rankin score; p < 0.001), M12 depressive symptoms (p < 0.0001), and M12 altered physical (p < 0.05) and mental (p < 0.0001) qualities of life were associated with M12 headaches.Conclusion: Persistent headaches are frequent one year after meningitis and are associated with quality of life alteration