Synthesis of Mesoporous Metal Oxides by Structure Replication: Thermal Analysis of Metal Nitrates in Porous Carbon Matrices

A variety of metal nitrates were filled into the pores of an ordered mesoporous CMK-3 carbon matrix by solution-based impregnation. Thermal conversion of the metal nitrates into the respective metal oxides, and subsequent removal of the carbon matrix by thermal combustion, provides a versatile means to prepare mesoporous metal oxides (so-called nanocasting). This study aims to monitor the thermally induced processes by thermogravimetric analysis (TGA), coupled with mass ion detection (MS). The highly dispersed metal nitrates in the pores of the carbon matrix tend to react to the respective metal oxides at lower temperature than reported in the literature for pure, i.e., carbon-free, metal nitrates. The subsequent thermal combustion of the CMK-3 carbon matrix also occurs at lower temperature, which is explained by a catalytic effect of the metal oxides present in the pores. This catalytic effect is particularly strong for oxides of redox active metals, such as transition group VII and VIII metals (Mn, Fe, Co, Ni), Cu, and Ce.

Outpatient tonsillectomy in children: a 7-year experience

OBJECTIVES

To report our centre's experience of outpatient tonsillectomy in children over a 7-year period and to evaluate the postoperative complication rate in this type of procedure compared to tonsillectomy performed in the context of conventional hospitalisation.

MATERIAL AND METHODS

Retrospective review of medical charts.

RESULTS

From May 2002 to April 2009, 276 tonsillectomies were performed on an outpatient basis, i.e. 55.4% of all paediatric tonsillectomies, in children with a mean age of 5.28 years. Ninety-six children (34.8%) presented clinical OSAS. Development of an early postoperative complication (before H8) required conventional hospitalisation on D0 in six (2.1%) of these 276 children operated on an outpatient basis: early postoperative bleeding in four cases (1.4%), which required reoperation to control bleeding in three cases, refusal to feed in one case (0.3%), and a parental problem in one case (0.3%). Postoperative complications occurring after H8 required readmission in six cases (2.1%): pain and feeding difficulties in two cases (0.7%) on D1 and D5, respectively, bleeding in four cases (1.4%) with reoperation before H24 for one patient, D5 for two patients and D7 for one patient. Only one case of bleeding occurred between H8 and H24. No perioperative respiratory complications were observed in children with clinical OSAS.

CONCLUSION

The results of this study show that, in line with international publications and meta-analyses, post-tonsillectomy complications between H8 and H24 postoperatively, mainly bleeding, are exceptional. Respiratory complications usually occur in high-risk clinical settings that are not eligible for outpatient surgery. Outpatient tonsillectomy is therefore a safe procedure in children presenting all of the required medical, social and organizational conditions.

An organometallic chimie douce approach to new Re(x)W(1-x)O3 phases

Re(x)W(1-x)O3.H2O and Re(x)W(1-x)O3 phases are prepared by a new organometallic chimie douce concept employing the organometallic precursor methyltrioxorhenium.

Two Ti-doped distrontium ruthenium tetraoxides: Sr2Ru0.93Ti0.07O4 and Sr2Ru0.81Ti0.19O4

Crystals of titanium-doped distrontium ruthenium tetraoxide, Sr(2)Ru(1-x)Ti(x)O(4), with x = 0.07 and 0.19, were grown by floating-zone melting, and their structures were solved using single-crystal X-ray diffraction. Increasing Ti content leads to a distinctive systematic variation of cell parameters and interatomic distances with respect to the undoped material.

Water and bromide in the active center of vanadate-dependent haloperoxidases

Two aqua-oxovanadium complexes, viz. [A-VO(H2O)(sal-L-Leu)] (1) and [VO(H2O)2(5-Br-sal-Gly)] x H2O(2 x H2O), containing the water ligands in cis- and trans-positions to the oxo group at V-OH2 distances ranging from 2.008 to 2.228 A, have been structurally characterized in order to model the apical electron density feature found in the structures of fungal and algal vanadate-dependent peroxidases. Br K-edge XAS of bromide-treated bromoperoxidase from Ascophyllum nodosum and model compounds (including 2 x H2O) has been used to show that the substrate bromide does not bind to active site vanadium but to a light atom, possibly carbon, in its vicinity.

Bromine K-edge EXAFS studies of bromide binding to bromoperoxidase from Ascophyllum nodosum

Bromine K-edge EXAFS studies have been carried out for bromide/peroxidase samples in Tris buffer at pH 8. The results are compared with those of aqueous (Tris-buffered) bromide and vanadium model compounds containing Br-V, Br-C(aliphatic) and Br-C(aromatic) bonds. It is found that bromide does not coordinate to the vanadium centre. Rather, bromine binds covalently to carbon. A possible candidate is active site serine.

First Isolation and Structural Characterization of a Nickel(III) Complex Containing Aliphatic Thiolate Donors

Long overdue were syntheses of nickel(III) complexes containing aliphatic thiolate ligands. The complex anion [Ni(phmi)]^- (phmi is the tetraanion of N,N'-1,2-phenylenebis(2-methyl-2-sulfanylpropionamide) has now been isolated-as PPh₄ salt-and structurally characterized. The stability of the nickel(III) complex is attributed to the special properties of the ligand, which abolish or at least retard possible decomposition pathways.

The effect of heparin and related proteoglycans on allergen and PAF-induced eosinophil infiltration

Exposure of normal guinea pigs to an aerosol of PAF induced a selective increase in the percentage of eosinophils in bronchoalveolar lavage (BAL) fluid 24 h after challenge. Challenge of actively sensitised guinea pigs with an aerosol of ovalbumin also induced a selective increase in the percentage of eosinophils recovered in BAL fluid 24 h post challenge. Pretreatment of actively sensitised guinea pigs or normal guinea pigs with unfractionated heparin significantly reduced such eosinophil infiltration induced by allergen or PAF challenge respectively, although higher amounts of heparin were required to inhibit antigen induced eosinophil infiltration. Similar effects were also observed following treatment with the low molecular weight heparin-like material ORG 10172 but not the anionic molecule polyglutamic acid or high molecular weight dextrans. These results suggest that proteoglycans may possess anti-allergic activity that is not necessarily related to either such molecules being anionic in nature nor to anti-coagulant activity.