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Pulsed laser ablation in liquid (PLAL) is a powerful method for producing nanoparticle colloids with a long-term stability despite the absence of stabilizing organic agents. The colloid stability involves different reactivities and chemical equilibria with complex ionic-specific effects at the nanoparticle/solvent interface which must be strongly influenced by their chemical composition. In this work, the surface composition of PLAL-produced gold nanoparticles in alkaline and saline (NaBr) water is investigated by X-ray photoelectron spectroscopy on free-flying nanoparticles, exempt from any substrate or radiation damage artifact. The Au 4f photoelectron spectra with a depth profiling investigation are used to evaluate the degree of nanoparticle surface oxidation. In alkaline water, the results preclude any surface oxidation contrary to the case of nanoparticles produced in NaBr solution. In addition, the analysis of Br 3d core-level photoelectron spectra agrees with a clear signature of Br on the nanoparticle surface, which is confirmed by a specific valence band feature. This experimental study is supported by DFT calculations, evaluating the energy balance of halide adsorption on different configurations of gold surfaces including oxidation or adsorbed salts.

We present the Aurore platform for ultrafast sciences. This platform is based on a unique 20 W, 1 kHz, 26 fs Ti:sapphire laser system designed for reliable operation and high intensity temporal contrast. The specific design ensures the high stability in terms of pulse duration, energy, and beam pointing necessary for extended experimental campaigns. The laser supplies 5 different beamlines, all dedicated to a specific field: attosecond science (Aurore 1), ultrafast phase transitions in solids (Aurore 2 and 3), ultrafast luminescence in solids (Aurore 4), and femtochemistry (Aurore 5). The technical specifications of these five beamlines are described in detail, and examples of the recent results are given.

Background: One in three women and one in five men are expected to experience a minimal-trauma-fracture after the age of 50-years, which increases the risk of subsequent fracture. Importantly, timely diagnosis and optimal treatment in the form of a fracture liaison service (FLS), has been shown to reduce this risk of a subsequent fracture. However, baseline risk of subsequent fracture among this group of FLS patients has not been well described. Therefore, this study aims to estimate absolute risk of subsequent fracture, among women and men aged 50-years or more, presenting to hospital with a minimal-trauma-fracture. Methods: Women and men aged 50-years or more with a minimal-trauma-fracture, presenting to hospitals across the South Western Sydney Local Health District between January 2003 and December 2017 were followed to identify subsequent fracture presentations to hospital. Absolute risk of subsequent fracture was estimated, by taking into account the competing risk of death. Results: Between January 2003 and December 2017-15,088 patients presented to the emergency departments of the five hospitals in the SWSLHD (11,149, women [74%]), with minimal-trauma-fractures. Subsequent fractures identified during the follow-up period (median = 4.5 years [IQR, 1.6-8.2]), occurred in 2024 (13%) patients. Death during the initial hospital stay, or during a subsequent hospital visit was recorded among 1646 patients (11%). Women were observed to have 7.1% risk of subsequent fracture after 1-year, following an initial fracture; and, the risk of subsequent fracture after 1-year was 6.2% for men. After 5-years the rate among women was 13.7, and 11.3% for men, respectively. Cumulative risk of subsequent fracture when initial fractures were classified as being at proximal or distal sites are also presented. Conclusion: This study has estimated the baseline risk of subsequent fracture among women and men presenting to hospital with minimal trauma fractures. Importantly, this inform

The surface chemistry of gold nanoparticles produced by the pulsed laser ablation in liquids method is investigated by X-ray photoelectron spectroscopy (XPS). The presence of surface oxide expected on these systems is investigated using synchrotron radiation in conditions close to their original state in solvent but free from substrate or solvent effects which could affect the interpretation of spectroscopic observations. For that purpose we performed the experiment on a controlled free-standing nanoparticle beam produced by combination of an atomizer and an aerodynamic lens system. These results are compared with those obtained by the standard situation of deposited nanoparticles on silicon substrate. An accurate analysis based on Bayesian statistics concludes that the existence of oxide in the free-standing conditions cannot be solely confirmed by the recorded core-level 4f spectra. If present, our data indicate an upper limit of 2.15 ± 0.68% of oxide. However, a higher credence to the hypothesis of its existence is brought by the structureless valence profile of the free-standing beam. Moreover, the cross-comparison with the deposited nanoparticles case clearly evidences an important misleading substrate effect. Experiment with free-standing nanoparticles is then demonstrated to be the right way to further investigate oxidation states on Au nanoparticles.

The chemical and geometrical structure of free-standing carbon dots (Cdots) prepared from the pyrolysis of N-hydroxysuccinimide (NHS) have been characterized using X-ray photoelectron spectroscopy (XPS). An aerodynamic lens system was used to generate a sufficient particle density of monodispersed Cdots for XPS studies at the PLEIADES beamline at the SOLEIL synchrotron facility. Varying the X-ray excitation energy between 315 and 755 eV allows probing of the Cdots from the surface toward their core, owing to the kinetic energy dependence of the photoelectron inelastic mean free path. The C 1s, O 1s, and N 1s core-levels were recorded with high-spectral resolution to identify their main chemical components and branching ratios. While high-resolution transmission electron microscopy (HRTEM) reveals a defective graphitic core, the C 1s spectrum evidence two main peaks similar to those measured from the solid NHS. Their relative abundance as a function of the probing depth is strongly related to the chemical composition of the ligand shell that does not vary substantially over the first 3.4 nm. Combining the depth-resolved XPS and HRTEM studies, it was concluded that the Cdots possess a graphitic core surrounded by a relatively homogeneous shell of at least 3.4 nm thickness with a composition similar to that of the solid NHS.

Objectives: To study the prevalence of Barrett esophagus (BE) (gastric and/or intestinal metaplasia) in adolescents treated for esophageal atresia (EA). Methods: This multicentric, prospective study included patients 15 to 19 year-old with medical history of EA. An upper endoscopy with standardized esophageal staged biopsies (at least 12) under general anesthesia was performed. Histological suspicion of metaplasia benefited from a centralized confirmation. Results: 120 patients aged 16.5 years (Â ± 1.4) were included. At evaluation, 8% had denutrition, 41% had an anti-reflux surgery performed and 41% had GERD symptoms with only 28% under medical treatment. Esophagitis was found at endoscopy in 34% and confirmed at histology in 67%. Endoscopy suspected BE in 37%, confirmed at histology in 43% (50 gastric and 1 intestinal). No endoscopic nor histological anomalies were found at the anastomosis. No significant relationships were found between BE and clinical symptoms. Multivariate analysis showed that BE was associated to EA without fistula (p = 0.03; OR = 0.21 [0.05–0.87]); previous multiple antireflux surgery (p = 0.04; OR = 3.29 [1.08–10.07]); BE suspicion at endoscopy (p < 0.001; OR = 0.04 [0.01–0.18]); histological esophagitis (p = 0.02; OR = 0.17 [0.04–0.73]). Conclusions: Patients with EA are at high risk of persistent GERD and BE. Long-time systematic follow-up of the esophageal mucosa including multistaged biopsies is therefore required even in asymptomatic patients.