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Combining experimental design with advanced characterisation methods provides a valuable opportunity to deepen our understanding of catalytic processes and their underlying mechanisms. Here, a series of hydroxyapatite doped with Fe2+ at different molar loadings noted HAP-FeX% (X = 1; 5.5 and 10; Ca/Fe molar ratio) were elaborated using a one-pot synthesis method. Characterization of these catalysts by various techniques such as ICP, BET/BJH, TGA/DSC, XRD, Raman, UV–visible, TPD-NH 3 , SEM, and TEM revealed substantial Fe2+ oxidation during synthesis, inducing changes in the morphological and physical-chemical characteristics of HAP caused by Fe3+/Ca2+ substitution. Furthermore, the synthesis produced nanoparticles (approximately 0.30 nm in size) on the hydroxyapatite surface, resulting from the precipitation of Fe/O phases. The catalysts exhibited good catalytic performance in methylene blue (MB) degradation through the photo-Fenton process (95 %). The Ca/Fe molar ratio = 8.8 %, [H 2 O 2 ] = 2.8 mmol L−1, and pH = 8.8 were optimized using the design of experiments (DOE) via response surface methodology (RSM). A mathematical model was developed to determine the influence of the Ca2+/Fe3+ substitution and the Fe/O phase on the catalytic activity. The results revealed the role of the Fe/O phase in the reaction initiation and the surface modification induced by Ca2+/Fe3+ substitution to facilitate the reaction chain. [Display omitted] • Fe2+ doped hydroxyapatite generates Fe3+/Fe2+, essential for achieving effective catalytic performance. • Fe2+ oxidation during the synthesis, inducing morphological modification in HAP due to Fe3+/Ca2+ substitution. • Active sites (∼ 0.30 nm in size) form on the surface of hydroxyapatite, from Fe-O phases precipitation. • High catalytic performance on the degradation of methylene blue by the photo-Fenton. [ABSTRACT FROM AUTHOR]

Study objective To evaluate the efficacy of oral melatonin to induce sedation (natural sleep) while measuring auditory brainstem responses (ABR) in children with suspected hearing loss by calculating the ABR success rate with the use of melatonin, the percentage of children in whom sleep was induced by melatonin and the time required to perform complete ABR testing. Material and methods Twenty-nine children aged 1 to 6 years were included in this prospective study. ABR testing was performed as a day-case procedure in a single room ensuring suitable sleeping conditions. Five milligrams of melatonin (or 10 mg in children over the age of 6 years) were administered orally before electrode positioning. An additional 5 milligrams were administered if the child failed to sleep after 30 minutes. Results ABR was performed with melatonin in 58 ears: complete ABR testing was performed in both ears in 19 children (65%), corresponding to 38 examinations; only one ear was tested in 7 children (24.2%), corresponding to 7 examinations; and ABR testing could not be performed in 3 children (10.3% failure rate). Good quality sleep was obtained in 17 children (59%), brief sleep was obtained in 4 children (14%), who nevertheless remained calm throughout the examination and 8 children (27%) did not fall asleep. The mean sleep-onset time after administration of melatonin was 41 minutes with a mean sleep time of 33 minutes and a mean examination time of 52 minutes after the first dose of melatonin. A complete examination therefore took an average of 93 minutes. Conclusion The use of melatonin allowed partial or complete ABR testing in 90% of children. This method is effective, but it requires adapted facilities to receive the child and the child's parents. [ABSTRACT FROM AUTHOR]

Introduction Gardner's syndrome is the association of familial adenomatous polyposis (FAP) with an anaphase promoting complex (APC) gene mutation and several extradigestive manifestations: osteomas, epidermal cysts and desmoid tumours. Only 2 cases of FAP associated with parotid tumour have been reported in the literature: one carcinoma and one pleomorphic adenoma. Case report We report the case of a 23-year-old man with Gardner's syndrome presenting with a fibromatous tumour of the left parotid gland. The other clinical manifestations were an osteoma of the skull base and a mesentery desmoid tumour. Left total parotidectomy was performed, followed by gastroscopy and colonoscopy, demonstrating numerous colonic adenomas. Genetic analysis revealed an APC gene mutation, confirming the diagnosis. Total prophylactic colectomy was performed. Conclusions This is the first reported case of Gardner's syndrome associated with a fibromatous tumour of the parotid. Early management of FAP is essential to prevent colorectal cancer that occurs in 100% of untreated cases. The rarity of this syndrome and the parotid site can lead to delayed diagnosis. [ABSTRACT FROM AUTHOR]

Gradually reduced graphene oxide materials were successfully synthesized by performing successive chemical treatments on graphite oxide synthesized using Hummers' method. These materials were deeply characterized using complementary spectroscopic techniques (X-ray induced photoelectron spectroscopy, UV- spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopy). It was shown that reduction processes allow removing oxygenated functional groups. Nevertheless, defects in the carbon structure materials formed subsequently to the oxidation step remain after such reducing treatments. CO stripping coupled with in-situ Fourier transform infrared spectroscopy measurements revealed that the reduction extent of the carbon-based materials affects the electron density on Pt thus engendering modifications in the adsorption strength of CO molecule. [ABSTRACT FROM AUTHOR]