Tribology of SiC/SiC Ceramic Matrix Composites in Liquid Oxygen in Relation to the Design of Hydrostatic Bearings

in Tribotest Journal (2003), 10(2), 105-115

This paper aims with the characterization of ceramic matrix composites for bearing applications in LOX. First, compatibility tests have been performed to assume the safety and feasibility of further ... [more ▼]

This paper aims with the characterization of ceramic matrix composites for bearing applications in LOX. First, compatibility tests have been performed to assume the safety and feasibility of further research operations. Then tribology tests were made on a pin-on-disc apparatus using LOX as working environment. The measurement of friction and wear allowed a comparison between different kinds of CMC and steel 440C materials. As a logical approach, a real geometry test rig is now being built up. The design of a hybrid journal bearing has been finished and the manufacturing of the rig components started. [less ▲]

"Les nouveaux paradigmes de l'enseignement des langues étrangères, en didactique, dans la pratique de classe, et dans la gestion de centres de langues"

Scientific conference (2003, December)

Applications de la susceptibilité magnétique et sédimentologie des carbonates, exemple du Frasnien de Belgique et du Canada.

Scientific conference (2003, December)

Amélioration de la santé par l'augmentation de la teneur en sélénium dans les viandes : section 1 : implication pour le bovin viandeux de fourrages produits avec des engrais enrichis en sélénium.

Report (2003)

8-Methyl-6-(4-methylpiperazin-1-yl)-11H-pyrido[2,3-b][1,4]benzodiazepine

in Acta Crystallographica Section E-Structure Reports Online (2003), 59(Part 12), 1990-1991

The conformation of the title compound, C18H21N5, is very similar to that observed in other diaryldiazepine structures such as clozapine and clozapine dihydrobromide. N-H...H hydrogen-bond interactions ... [more ▼]

The conformation of the title compound, C18H21N5, is very similar to that observed in other diaryldiazepine structures such as clozapine and clozapine dihydrobromide. N-H...H hydrogen-bond interactions result in the formation of a dimer. [less ▲]

Survey of gastric lesions and blood pepsinogen levels in pigs in Burkina Faso

in Veterinary Research Communications (2003), 27(8), 595-602

The purpose of the study was to investigate the prevalence of gastric lesions and to provide diagnostic values for serum pepsinogen in non-infected pigs and in pigs with gastric disease. In an abattoir ... [more ▼]

The purpose of the study was to investigate the prevalence of gastric lesions and to provide diagnostic values for serum pepsinogen in non-infected pigs and in pigs with gastric disease. In an abattoir survey, the pepsinogen concentrations were measured in the serum from 62 non-infected pigs, 33 pigs with gastric lesions and 17 pigs infected with Hyostrongylus rubidus, using a specific radioimmunoassay (RIA). The mean (+/-SE) pepsinogen concentrations in the serum of non-infected pigs, in pigs with gastric ulcers, and in pigs with a heavy H. rubidus infection were 630.8 +/- 39.2 ng/ml, 1084.5 +/- 166.2 ng/ml and 1095.2 +/- 102.3 ng/ml, respectively (p < 0.05). Because of the higher concentrations of pepsinogen in the blood of pigs with gastric ulcers or parasitic infections, it is suggested that the measurement of serum pepsinogen by RIA may be an effective biochemical approach to the diagnosis of chronic gastric disorders in pigs. [less ▲]

Synthèse et caractérisation de nanocharges inorganiques lamellaires à haut rapport d'aspect

Doctoral thesis (2003)

Experimental study of the thermo-hydraulic performances of humid air condensers

Report (2003)

Intrahepatic synthesis of tumor necrosis factor-alpha related to cardiac surgery is inhibited by interleukin-10 via the Janus kinase (Jak)/signal transducers and activator of transcription (STAT) pathway.

in Critical Care Medicine (2003), 31(12), 2769-75

SUMMARY: OBJECTIVES To identify the signaling pathways involved in the anti-inflammatory shift of the cytokine balance due to hypothermia during cardiopulmonary bypass. DESIGN Experimental animal study ... [more ▼]

SUMMARY: OBJECTIVES To identify the signaling pathways involved in the anti-inflammatory shift of the cytokine balance due to hypothermia during cardiopulmonary bypass. DESIGN Experimental animal study. SETTING Department of experimental surgery of a university hospital. SUBJECTS Young pigs. INTERVENTIONS Animals underwent normothermic (37 degrees C) or hypothermic (28 degrees C) cardiopulmonary bypass (n = 6 each). Samples of liver tissue were taken before and 6 hrs after cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS Intrahepatic expression of tumor necrosis factor-alpha, interleukin-10, inducible nitric oxide synthase, and suppressor of cytokine signaling-3 was detected by reverse transcriptase polymerase chain reaction and/or Western blotting. Concentrations of the inhibitory protein of nuclear factor-kappaB, IkappaB, and of the signal transducer and activator of transcription (STAT)-3 were measured by Western blotting. The DNA-binding activity of nuclear factor-kappaB and STAT-3 was assessed by electrophoretic mobility shift and supershift assays. Liver cell necrosis and apoptosis were assessed by histology and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay, respectively. Pigs operated on in hypothermia showed significantly higher intrahepatic concentrations of interleukin-10 and lower concentrations of tumor necrosis factor-alpha than the others. They also showed a lower percentage of hepatic cell necrosis but not of apoptosis. This anti-inflammatory reaction observed in the hypothermic group was associated with a higher expression of suppressor of cytokine signaling-3 and with increased activation of STAT-3. Activation of nuclear factor-kappaB and expression of inducible nitric oxide synthase, however, were not significantly different between both groups. CONCLUSION Our results show that hypothermia during cardiopulmonary bypass up-regulates interleukin-10 via STAT-3 activation, which in turn leads to the attenuation of tumor necrosis factor-alpha expression and to hepatic protection. [less ▲]

ac magnetic behavior of large-grain magnetoresistive La0.78Ca0.22Mn0.90Ox materials

in Physical Review. B (2003), 68(22), 224418

We report a detailed set of ac magnetic measurements carried out on bulk large grain La-Ca-Mn-O samples extracted from a floating zone method-grown rod. Three samples with La0.78Ca0.22Mn0.90Ox ... [more ▼]

We report a detailed set of ac magnetic measurements carried out on bulk large grain La-Ca-Mn-O samples extracted from a floating zone method-grown rod. Three samples with La0.78Ca0.22Mn0.90Ox stoichiometry but differing in their microstructure were investigated by electrical resistivity and ac susceptibility measurements: (i) a single grain sample, (ii) a sample containing two grains, and (iii) a polycrystalline sample. We show that the superimposition of dc magnetic fields during ac magnetic susceptibility measurements is an efficient way for characterizing the magnetic transition of samples with different microstructures. Whereas both single grain and polycrystalline samples display a single susceptibility peak, an additional kink structure is observed in the case of the double grain sample. The temperature dependence of the ac susceptibility measured with superimposed dc magnetic fields is analyzed in the framework of second-order phase transition ideas. The relations between the critical exponents (beta+gamma ~ 1.5, delta ~ 2.5) are found to be close to those of the mean-field model for all samples. This is attributed to the disordering caused by unoccupied Mn sites. ©2003 The American Physical Society. [less ▲]