Influence of framework Si/Al ratio and topology on electron transfers in zeolites.

H-ZSM-5 and H-*BEA zeolites were hydrothermally synthesized with different Si/Al ratios (∼12 to ∼40). The physico-chemical properties of the resulting materials were fully characterized by several techniques (NMR, BET, PXRD, and pyridine thermal desorption followed by infrared spectroscopy). To assess the effect of the zeolite type and Si/Al ratio on sample reactivity, the charge separation processes between the zeolite framework and the adsorbed trans-stilbene (t-St) molecule were investigated by UV-visible diffuse reflectance and FT-Raman spectroscopy. The UV-visible absorption spectra obtained after t-St adsorption show a clear difference depending on the zeolite type. It appears that the radical cation resulting from t-St spontaneous ionization is more stabilized in the MFI-type framework than in the *BEA topology. However, the amount and stability of the electron-hole pair resulting from the radical cation evolution to a charge transfer complex are more important in the *BEA zeolite. On the basis of the experimental results and physico-chemical properties of the sample, we found that the radical cation and the electron-hole stabilities are strongly dependent on the amount of hexacoordinated aluminum (Al(VI)) and more precisely on their environment, i.e. the distance between Brønsted sites and strong Lewis sites or Brønsted Strong Lewis Pairs (BSLPs).

Influence of hierarchization on electron transfers in structured MFI-type zeolites.

H-ZSM-5 zeolite (Si/Al = 19.3) was hydrothermally synthesized. Alkaline and/or acid post-synthesis treatments were carried out to give rise to an interconnected mesoporous volume. The desilication treatment parameters have been tuned (temperature, organic base addition) to obtain a series of samples with increasing mesoporous volume and a constant number of acid sites. The physico-chemical properties of the resulting materials were fully characterized by many techniques (NMR, BET, PXRD, and pyridine thermal desorption followed by infrared spectroscopy). To assess the effect of post-treatments on sample reactivity, the charge separation processes between the zeolite framework and adsorbed trans-stilbene (t-St) molecule were investigated by UV-visible diffuse reflectance. The spectra obtained after t-St adsorption show clear differences depending on the applied post-treatments. It appears that the desilication treatments performed without acidic washing highly stabilize the radical cation resulting from the t-St spontaneous ionization. In contrast, by applying acidic washing after desilication, the ionization process becomes significantly weaker. The results show that the proportion of strong Lewis acid sites in the vicinity of Brønsted sites named Brønsted Strong Lewis Pairs (BSLP), are responsible for the amount of radical cations observed in the different samples. More precisely, it exists an optimal proportion of BSLP to achieve a high ionization rate. On the basis of the experimental results a mechanism for the formation of the t-St radical cation and the charge transfer complex (CTC) is proposed.

A drastic influence of the anion nature and concentration on high pressure intrusion-extrusion of electrolyte solutions in Silicalite-1.

High pressure intrusion-extrusion of concentrated solutions of sodium salts in a pure-silica MFI-type zeolite (Silicalite-1) was studied for potential applications in mechanical energy absorption and storage. It was discovered that the anion nature has a drastic influence on the behavior and the energetic performances of "Silicalite-1 - concentrated Na+X- solution" systems, where X = Cl-, Br-, I-, NO2-, NO3-, ClO4- and CrO42-. In the case of NaNO2, NaClO4, Na2CrO4, and NaI a combination of bumper and shock-absorber behaviors with a partial irreversible solution intrusion was observed, whereas a fully reversible spring behavior is demonstrated for the intrusion-extrusion of NaBr, NaCl and NaNO3 solutions. In comparison with water, the intrusion pressure increases for all the solutions except for NaClO4 one. The irreversibility of intrusion decreases with a dilution rate, and the behavior of the corresponding systems with diluted solutions becomes very close. The variation of the system behavior and intrusion pressure values can be related to a different affinity of the corresponding anions for the pores of Silicalite-1. The samples before and after intrusion-extrusion experiments were characterized using several structural and physicochemical methods (XRD, TGA, solid-state NMR, and N2 physisorption), but no significant structural difference was observed.

Drastic change of the intrusion-extrusion behavior of electrolyte solutions in pure silica *BEA-type zeolite.

High pressure water and electrolyte solutions intrusion-extrusion experiments in pure-silica *BEA-type zeolite (zeosil ß) were performed in order to study the performances of these systems in energy absorption and storage. The "zeosil ß-water" system displays a bumper behavior with an intrusion pressure of 53 MPa and an absorbed energy of 8.3 J g(-1). For the "zeosil ß-LiCl aqueous solutions" systems the intrusion pressure increases with the LiCl concentration to 95, 111 and 115 MPa for 10, 15 and 20 M solution, respectively. However, for concentrations above 10 M, a transformation of the system behavior from bumper to shock-absorber is observed. The zeolite samples were characterized by several structural and physicochemical methods (XRD, TGA, solid-state NMR, N2 physisorption, ICP-OES) before and after intrusion-extrusion experiments in order to understand the influence of the LiCl concentration on the intrusion-extrusion behavior. It is shown that the intrusion of water and LiCl solutions with low concentration leads to the formation of Si-(OSi)3OH groups, whereas no defects are observed under intrusion of concentrated LiCl solutions. A possible mechanism of LiCl solution intrusion based on separate intrusion of H2O molecules and Li(H2O)x(+) ions is proposed.

[Rhinofacial mucormycosis: A case report]. / Mucormycose rhinofaciale : à propos d'un cas.

INTRODUCTION: Mucormycosis is the third among deep fungal opportunistic infections after candidiasis and aspergillosis. It is a rare fungal infection in children, but often fatal, which occurs in immunocompromised patients. It is caused by fungi belonging to the order of mucorales. It causes extensive damage and decaying soft parts. The authors report the case of a sinonasal mucormycosis with fatal outcome in a child suffering from hemophagocytic syndrome. REPORT: PL, aged 23 months, resulting from non-consanguineous parents, hospitalized for management of hemophagocytic syndrome lasting for 2 months suspected on clinical and biological data. This diagnosis was confirmed on histology. The etiological diagnosis was negative. A broad-spectrum antibiotics and corticosteroids was introduced. A month later, the patient developed necrotic lesions in the nose and facing the right maxillary sinus. CT scan of facial mass objectived ethmoïdomaxillary bilateral sinusitis. The mycological examination of a nasal swab showed the presence of non-compartmentalized hyphae, culture on Sabouraud chloramphenicol medium without actidione at 37°C isolated Absidia corymbifera. Treatment with amphotericin B was initiated but not tolerated. The negative trend was rapidly leading to death. CONCLUSION: Rhinocerebral mucormycosis is a rare fungal infection in children, we must know how to keep it in mind. The mycological examination and/or histology of a local levy allows rapid diagnosis. Treatment should be initiated urgently to improve the prognosis.

Gas-phase vibrational spectroscopy and ab initio study of organophosphorus compounds: discrimination between species and conformers.

Gas phase vibrational spectra of dimethyl methylphosphonate (DMMP), trimethyl phosphate (TMP), and triethyl phosphate (TEP) have been measured using FTIR spectroscopy. For DMMP, TMP, and TEP, most of the infrared active vibrational modes have been observed in the 50-5000 cm (-1) spectral range, allowing an unambiguous discrimination between the three molecules. The vibrational analysis of the spectra was performed by comparing with MP2 and B3LYP harmonic and anharmonic force field ab initio calculations. The extension to anharmonic calculations provides the best agreement for the mid-infrared and the near-infrared spectra, but they do not improve the harmonic frequency predictions in the far-infrared domain. This part of the vibrational spectra associated with collective and nonlocalized vibrational modes presents the largest frequency differences between the two lowest energy conformers of DMMP and TMP. These two conformers were taken into account in the vibrational assignment of the spectra. Their experimental evidence was obtained by deconvoluting vibrational bands in the mid-infrared and in the far-infrared regions, respectively. For TEP, the conformational landscape appears very complicated at ambient temperature, and a further analysis at low temperature is required to explain the vibrational features of each conformer.

[Traumatic false aneurysms of intracranial artery]. / Les faux anévrismes artériels traumatiques intracrâniens.

The authors report a case of intracranial traumatic aneurysm at young a 21 years old patient. He presented with recurrent epistaxis 3 months after craniofacial trauma. An aneurysm of the left carotid artery was diagnosed at cerebral angiography. Endovascular treatment was performed with favorable outcome. In spite of their rarity, posttraumatic intracranial aneurysms should be suspected in patients with recent or remote history of trauma, even minor, presenting with secondary clinical deterioration, in order to carry out emergent angiographic exploration, before contemplating definitive surgical or endovascular treatment.