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Aims: In cases of malignant distal biliary obstruction, ERCP is the preferred technique for bile duct drainage. In case of failure, the alternative techniques are percutaneous transhepatic biliary drainage (PTBD) and more recently endoscopic ultrasound-guided biliary drainage. A new type of stent called the electrocautery-enhanced lumen-apposing metal stent (EC-LAMS) has been developed to enable the performance of biliary-enteric anastomosis under EUS-guidance in a single step, without prior bile duct puncture or the need for a guidewire. The aim of our study was to compare the real-life efficacies of PTBD and EUS-BD with the EC-LAMS for cases of ERCP failure in patients with malignant biliary obstruction. Methods: We performed a monocentric retrospective study comparing PTBD and EUS-BD with the use of electrocautery-enhanced lumen-apposing metal stent in the context of a malignant distal biliary obstruction after ERCP failure. Results: 95 patients were included (50 in EUS-BD group and 45 in PTBD group). The main etiology of malignant obstruction was adenocarcinoma of the head of pancreas (85%). There was a significant difference in favor of endoscopic ultrasound-guided biliary drainage using electrocautery-enhanced lumen-apposing metal stent for the following criteria: clinical success: 89.3% vs. 45.5%; p< 0.0001; procedure-related adverse event rate: 2.12% vs. 22.7%; p= 0.003; duration of post-drainage hospitalization: 3.5 vs. 8.2 days; p< 0.0001, overall survival (median survival): 118.2 vs. 42 days; p= 0.012, overall cost of the strategy per patient: 5098 vs. 9363 euros; p< 0.001. Conclusion: Our results are in favor of EUS-BD using electrocautery-enhanced lumen-apposing metal stent in case of ERCP failure for a distal tumor biliary obstruction. Operators performing ERCP for distal tumor biliary obstruction must learn this backup procedure because of its superiority over percutaneous transhepatic biliary drainage in terms of clinical success, safety, cost, and overall survival.

La détermination de l’atteinte médiastinale chez les patients non métastatiques est un temps essentiel de la prise en charge initiale de tout cancer broncho-pulmonaire non à petites cellules permettant de décider du traitement le plus adapté à proposer au patient. Si la chirurgie constitue une référence puisqu’elle a une meilleure valeur prédictive négative, l’échoendoscopie (oesophagienne ou bronchique) est recommandée en première intention pour le staging car elle est performante, qu’il existe moins de complications consécutives, que les coûts engagés sont moins importants et qu’elle peut par ailleurs être réalisée sans anesthésie. Les explorations plus invasives restent indiquées lorsque les prélèvements réalisés lors de l’endoscopie sont négatifs ou lors de la réévaluation après réalisation d’un traitement d’induction qui est un cas à part. De la complémentarité de ces deux examens est né le CUS (combined utrasound) permettant un staging médiastinal médical quasi-complet. Cette technique plus sensible est cependant difficile à organiser en pratique raison pour laquelle d’authentiques explorations para-oesophagiennes sont maintenant réalisées par les pneumologues à l’aide de leur échobronchoscope (EUS-B).

Nd3+doped CaF2monocrystalline films have been grown by molecular beam epitaxy using CaF2and NdF3evaporation on CaF2substrates. The effect of Nd3+concentration is studied by means of the photoluminescence signal of Nd3+ions. The results can be compared favourably with those obtained on CaF2:Nd bulk crystals. For a given Nd3+concentration a lower quantity of Nd3+aggregate centers is observed. Nd3+ions can therefore be efficiently incorporated as isolated Nd3+-F-centers up to a concentration of 6 wt % Nd3+without emission quenching of their associated line at 1045.7 nm.

Les thermistances CTN constituées de manganites de métaux de transition présentent généralement des phénomènes de vieillissement sous contrainte thermique. Les dérives observées dépendent de la composition, de la structure (cubique ou quadratique), des traitements thermiques subis par la céramique. Afin de tenter d'expliquer les corrélations entre l'influence des traitements thermiques et les phénomènes de vieillissement, nous avons procédé à une étude en microscopie électronique. D'une façon générale, les céramiques refroidies très lentement présentent des grains exempts de dislocations ou de défauts-plans. Au contraire, les céramiques trempées sont toujours polyphasées et présentent des densités importantes de dislocations et de défauts-plans. Ces défauts bidimensionnels se manifestent sous forme de lamelles soit d'épaisseur comprise entre 30 et 600 nm (micromacles ou exsolutions), soit d'épaisseur beaucoup plus faible (structure “ tweed”). Les phénomènes de vieillissement semblant liés à des diffusions atomiques dans le réseau spinelle, ces défauts intragranulaires pourraient jouer le rôle de barrières vis-à-vis de la mobilité des ions et expliqueraient la meilleure stabilité thermique des céramiques trempées.

Negative Temperature Coefficient (NTC) thermistors made of spinel structure transition metal manganites usually display ageing phenomena under thermal stress. Their resistance drift depends on their composition, crystal structure (cubic or tetragonal) and heat treatments. We have previously shown in iron manganite thermistors, Mn3-xFexO4(with 0 ≤x ≤1.51), that the ageing is due to the migration of Fe3+and Mn2+ions between tetrahedral and octahedral sites of the spinel structure. Iron manganites were investigated by Transmission Electron Microscopy (TEM) in order to relate microstructure to electrical stability. For iron manganites with iron content x ≤0.78, two dimensional defects result in a domain microstructure (microtwins). As x increases and exceeds 0.78, the domain structure gradually vanishes and transforms into a tweed microstructure (x = 1.05) and, for x > 1.30, no bidimensional defects are observed. Thus it is suggested that the microstructural disturbance plays an important role in the kinetics of the ion migration during the ageing of the studied ceramics.

Molecular beam epitaxy of CaF2monocrystalline layers Er3+doped up to a concentration of 50 mol% is demonstrated on CaF2substrates. Separated effusion cells containing CaF2and ErF3have been used. The photoluminescence spectra of these thin layers exhibit emissions from centers which were found to correspond to those already reported for CaF2: Er3+bulk crystals. The influence of growth temperature and Er concentration on the spectroscopic properties of these layers was investigated. The 1.54 µm emission of interest was shown to behave as aggregate centers, and the integrated luminescence was only quenched for concentrations higher than 35 mol%. The trends observed evidence that molecular beam epitaxy is a powerful technique for growing thin Er-doped fluoride layers.

Angular-dependent reflection measurements were used to map out the dispersion relations of the resonant Bloch modes, and the angular dispersion of the phonon modes, in a photonic crystal consisting of selectively grown GaN pyramids containing a single InxGa1–xN/GaN quantum well. The dispersion of the photons exhibits strong photonic crystal characteristics, while the mean indium content of the ∼2 nm thickness InxGa1–xN layer was extracted from the angular dispersion of the phonon modes. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Simulations of an ICFB waste combustor are reported with a mathematical model that includes reaction kinetics related to carbon, nitrogen, hydrogen, oxygen and sulphur content of industrial waste. The model assumes formation of volatile and char during the thermal treatment of wastes, followed by a series of homogeneous and heterogeneous reactions catalyzed by bed material such as char and ash+sand. The trends of model predictions are in qualitative agreement with experimental observations from thermal treatment of spent foundry sand in a 20kW ICFB pilot unit. According to the kinetics and experimental data, bed materials are strongly responsible for low level emissions of nitrogen oxides and sulphur dioxide. The validated model allows a comprehensive simulation analysis to be performed by varying some operating parameters such as waste feedrate, aeration rate, solid circulation and reacting zones. The study reveals that for a proper combustor operation, a balance has to be made between combustion efficiency, lower carbon monoxide and nitrogen oxides emission, as well as sulphur dioxide capture.

The disposal of sludge generated by water treatment plants poses major financial and environmental problems. Drying of the sludge is an essential pan of any disposal process which may include incinerating, landfilling or upgrading. In the present study, experiments were carried out to investigate the drying of sludge in a spouted bed and to characterize the hydrodynamics and mass transfer mechanisms. The effect of bed moisture content on the minimum spouting velocity (Ums) was examined for sludge granules. Ums was found to increase with increasing the moisture content of the sludge particles. The gas phase mass transfer coefficient in the dryer was determined using porous calcined alumina particles and the results were compared with predictions by correlations available in the literature. The existing correlations gave poor predictions for the mass transfer coefficient. A new correlation for the mass transfer coefficient in a spouted bed dryer was developed based on the experimental results.

Single-phase copper manganite spinels CuxMn3-xO4 with 0?x?1 were prepared by a careful thermal processing of copper-manganese co-precipitated hydroxide precursors. Powder X-ray diffraction (XRD) analysis of these spinels revealed the presence of a tetragonally distorted single spinel phase, with tetragonal distortionc/a > 1 which decreases with copper content. Thermogravimetric analysis (TGA) curves, run in an oxygen atmosphere for all the compositions studied, are characterized by a stability step up to 250 to 300° C, followed by a domain of oxidation between 300 and 900° C and finally a domain of reduction that restores the initial stoichiometry of the samples. The oxidation is observed to occur in two successive steps. The phenomenon appearing at the low temperature is due to the oxidation of Cu+ ions, while that at higher temperature corresponds to the oxidation of Mn2+ ions in tetrahedral sites. Further, electrical resistivity measurements confirm the presence of Cu+ ions on the tetrahedral sublattice of spinel. Correlation of the results obtained by XRD, TGA and electrical resistivity measurements permits one to infer the cation distribution, given by Cux+Mn1-x2+[Mn2-x3+Mnx4+] O42-.

Pr3+-doped CaF2layers on CaF2(111) substrates were grown by molecular beam epitaxy. The effect of Pr concentration on spectroscopic properties and waveguide characteristics of the thin films was investigated and the existence of clustering of the tripositive praseodyme ions in CaF2was put forward to explain certain optical results. Photoluminescence spectra were obtained in the wavelength range 590–650nm for 3P0→3F2and 3P0→3H6transitions of Pr3+ions, and a 3P0level lifetime of the order of 100μs was measured. This work demonstrates that active optical waveguides, useful for integrated optoelectronic devices, can be produced by growing Pr-doped CaF2epitaxial layers.

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The hydrodynamic behavior of particles in circulating fluidized beds has been studied by means of a Boltzmann-like kinetic model. Two main regimes of flow: a homogeneous and a heterogeneous regime have been delimited. In the homogeneous regime, for concentrations below a critical value, the flow consists of upward moving solids. Above the critical concentration, clusters appear. Particles velocity distribution at different values of the solid concentration and the ratio of particles being in clusters to those being in homogeneous flow are calculated for different solid mass fluxes, particle size distributions and superficial gas velocities. Slip factors and the effect of gas radial velocity profile have been predicted. Qualitative agreement with experimental data is obtained.

Liquid-phase sintering (LPS) of ceramics issued from powders of bismuth-titanium-doped zinc oxide, made of spherical grains constituted of small crystallites, were studied by dilatometry. A correlation can be established between the shape of the shrinkage curves and the microstructure of the ceramics. During sintering the spherical grains are destroyed as soon as the liquid phase appears and the rearrangement proceeds directly between crystallites. Systematic studies were carried out on bismuth-titanium-doped ZnO. For small Bi contents, the beginning of a solid-phase sintering process occurs. For 1 at % Bi in the binary system Bi-doped ZnO, rapid shrinkage leads to a well-densified ceramic with a grain size of 70 µm on average. The influence of the amount of titanium iny% Ti-1% Bi-doped ZnO is discussed. Whatever the amount of Ti, LPS is observed. The shrinkage curves depend greatly on the amount of Ti: only a Ti content ofy=0.6 % leads to an increase in grain size (100 µm on average).

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Single-phase nickel manganite spinels, NixMn3-xO4, with 0.5 ?x ? 1, were prepared by a careful thermal processing of nickel-manganese coprecipitated oxalate precursors. Powder X-ray diffraction analysis of the spinel revealed the presence of cubic single spinel phase with parametera which decreases with nickel content. The lattice parameter variation can be explained in terms of the distribution of Ni2+ ions on the octahedral sites. Therefore, a fine analysis of data shows that some Ni2+ ions (forx>0.56) are located in tetrahedral sites. The percentage of nickel in A-sites increases with nickel content (x) following the relation % Ni2+ in A sites =P = - 82.1x2+192.4x-81.5 and thus the general formula for cation distribution is $${\text{Mn}}_{{\text{1 - }}y}^{{\text{2 + }}} {\text{Ni}}_y^{{\text{2 + }}} [{\text{Ni}}_{x{\text{ - }}y}^{{\text{2 + }}} {\text{Mn}}_{{\text{2 - 2(}}x - y)}^{{\text{3 + }}} {\text{Mn}}_{x{\text{ - }}y}^{{\text{4 + }}} ]{\text{O}}_{\text{4}}^{{\text{2 - }}} $$ withy=xP/100

Existing correlations for predicting minimum spouting velocity in conical spouted beds have been found to give poor agreement with available literature data. A new correlation has been developed based on literature data to give much better prediction of the minimum spouting velocity for both small and pilot‐scale conical‐spouted beds.

Summary: The mineral of cortical bones has been studied in newborn, growing, and adult rats and in the calf and cow, using X-ray diffraction and infrared spectroscopy during the thermal decomposition of bones and by microassay of carbonate. The mineral of all the bone samples, regardless of species or age, was found to be a calcium-deficient apatite containing both CO32− and HPO42− ions in the crystal lattice. The crystal size, Ca/P molar ratio, and CO32− ion content of cortical bone all increased with increasing age in both the rat and the bovine. The Ca/P ratio varied from 1.51 in newborn rats to 1.69 in adults but remained that of Ca-deficient apatite even though its value was close to that of stoichiometric hydroxyapatite (1.67). Both the carbonate ion and the hydrogenophosphate ion contents varied from one animal species to another and with age within a given species. Maturation was correlated with an increase in carbonate ion content, which replaced the HPO42− ions. In contrast, the calcium ion number per unit formula did not vary during maturation. Cortical bone mineral, in both species, regardless of age, can therefore be represented by the following formula: Ca8.3(PO4)4.3(CO3)x(HPO4)y(OH)0.3; y decreased and x increased with increasing age, (x+y) being constant, equal to 1.7.

The authors have designed, fabricated and characterised singlemode rib optical waveguides at 1.55 µm with high form birefringence. The core of the waveguide, which is composed of alternate layers of GaAs and AlAs, propagates both TE00 and TM00 modes with good vertical and lateral confinement, and presents a modal birefringence of > 0.047 at 1.55 µm. This is an essential step for the conception of acousto and optoelectronic components on multiquantum well structures.

Résumé Un cas clinique de fracture bilatérale du col du radius chez un adulte est rapporté par les auteurs. L'embrochage centro-médullaire ascendant, dérivé de la technique de Métaizeau décrite chez l'enfant, paraît particulièrement indiquée dans les fractures sous-capitales engrenées de l'extrémité supérieure du radius, résultant d'un traumatisme par mécanisme de compression et tassement.

The authors present room temperature four-wave mixing experiments on a subpicosecond timescale at the band edge of bulk GaAs integrated into microcavities. In the cavity, the diffraction efficiency η ≃ 8 × 10-3 is enhanced by approximately a factor of 20 at 890 nm compared to bulk GaAs without cavity. This result shows the potential capability of microcavities for reducing the switch energy of many all-optical devices.