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The work presented in this paper is devoted to the impact on Ni substrates of molten oxide particles (yttria-stabilized zirconia (YSZ)) either in the micrometer-sized range (between 20 and 100 µm) or in the submicrometer range (between 0.3 and 1.1 µm). YSZ was chosen because no oxidation occurs when plasma-spraying it in air. Micrometer-sized particles were injected into a hot plasma stream obtained with a DC plasma torch (Oerlikon Metco F4 torch) working with a mixture of Ar and H2 (Ar 33 slm and H2 10 slm). Correlatively an ethanol suspension of submicrometer-sized particles was injected into an Ar–He (Ar 40 slm and He 20 slm) DC plasma jet. Upon impact on a smooth Ni substrate preheated in air at 610 K both sizes of particles flatten and form splats. To achieve a much better understanding of splat formation, measurements of the velocity and temperature of an in-flight single particle just prior to its impact and at its impact were developed. Unfortunately, with submicrometer-sized particles, in-flight measurements of a single particle become impossible and only mean values resulting from a few particles are measured, making interpretation trickier. This study focused on the flattening on smooth substrates, presented as Part I, and will be followed by another study, to be presented as Part II, concerning splat formation on rough substrates adapted to the size of sprayed particles and then splat layering. Of course, the rough surfaces will also be preheated as the smooth ones at 610 K. [ABSTRACT FROM AUTHOR]

Spray pyrolysis process has been used for the synthesis of non-oxide ceramic powders from liquid precursors in the Si/C/N system. Particles with a high thermal stability and with variable composition and size distribution have been obtained. In this process, the mechanisms involved in precursor decomposition and gas phase recombination of species are still unknown. The final aim of this work consists in improving the whole process comprehension by an experimental/modelling approach that helps to connect the synthesized particles characteristics to the precursor properties and process operating parameters. It includes the following steps: aerosol formation by a piezoelectric nebulizer, its transport and the chemical-physical phenomena involved in the reaction processes. This paper focuses on the aerosol characterization to understand the relationship between the liquid precursor properties and the liquid droplet diameter distribution. Liquids with properties close to the precursor of interest (hexamethyldisilazane) have been used. Experiments have been performed using a shadowgraphy technique to determine the drop size distribution of the aerosol. For all operating parameters of the nebulizer device and liquids used, bimodal droplet size distributions have been obtained. Correlations proposed in the literature for the droplet size prediction by ultrasonic nebulization were used and adapted to the specific nebulizer device used in this study, showing rather good agreement with experimental values., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Because neurological failure is the most frequent extra-cardiac complication in Infectious Endocarditis (IE), a brain computerised tomography (CT) scan is usually performed. The benefits of magnetic resonance imaging (MRI) have not been clearly established. This study aims to clarify the prevalence and type of cerebral lesions in IE detected using MRI and to compare them with those detected using CT scans., Methods: In the Grenoble University Hospital, patients diagnosed with definite or possible endocarditis according to Duke's criteria were screened from 2010-2012. Brain CT and MRI were performed as soon as possible after diagnosis., Results: Of the 62 patients with IE who underwent at least one cerebral imaging within 3 weeks of diagnosis, Streptococcus (29) and Staphylococcus (14) were the main micro-organisms present. Twenty-eight (45%) patients underwent cardiac surgery. Eight (13%) died before discharge. Twenty (32%) had neurological symptoms. A brain CT-scan was performed on 53 (85%) patients and a MRI was performed on 43 (69%) patients. CT was pathological in 26 (49%) patients, whereas 32 (74%) MRI demonstrated abnormalities. The MRI lesions were classified as follows: ischaemia (48%), microbleeds (34%), haemorrhages (16%), abscesses (9%) and microbial aneurysms (4%). Of the 37 patients who underwent both MRI and CT examinations, ischaemia (48% vs 35%) and microbleeds (34%) demonstrated the difference between the two imaging methods., Conclusion: Through the early diagnosis of cerebral damage, even in asymptomatic cases, MRI may have a role in the IE management, influence any surgical decision and assist in prognosis assessment.

Borrelia crocidurae-associated relapsing fever is endemic to West Africa and is considered benign. We report 4 patients with B. crocidurae-associated neurologic symptoms; 2 of their cases had been misdiagnosed. Frequency and severity of this disease could be underestimated; molecular methods and serodiagnostic tests for Lyme disease might be helpful in its detection.

Background: The effectiveness of Helicobacter pylori eradication regimens is influenced by antibiotic susceptibility of infecting strains. Data concerning antibiotic resistance in children are limited. We report the evolution of primary and secondary resistance in a series of Belgian children during the last 12 years., Patients and Methods: From 1989 through 2000, H. pylori gastritis was diagnosed in 569 children, and antibiotic susceptibility tests were performed in 555. Eradication, using different schemes, failed in 128 of 457 treated children. After eradication failure antibiotic susceptibility determination was performed in 87 of 128. Comparison of antibiotic susceptibility of strains isolated from the gastric body and from the antrum was performed in 238 samples., Results: Resistance to amoxicillin was not observed. The rate of primary resistance to nitroimidazole derivatives was 18.0% (101 of 555) and remained constant throughout this period, whereas primary resistance to macrolides increased from an average of 6.0% (range, 0 to 10%) before 1995 to 16.6% (range, 10 to 25%, P < 0.001) thereafter. Antibiotic consumption in Belgium, especially macrolides, did not show important fluctuations during the study period. Secondary resistance developed in 39 of 87 patients (46%). Strains isolated from different gastric locations show identical susceptibility testing in all but 5 of 238., Conclusions: Resistance of H. pylori to macrolides increased in our pediatric population which did not appear to correlate with macrolides prescription habits in our country. After eradication failure acquired secondary resistance was observed in one-half of the patients.