Dealloying of Cobalt from CuCo Nanoparticles under Syngas Exposure

International audienceThe structure and composition of core−shell CuCo nanoparticles were found to change as a result of cleaning pretreatments and when exposed to syngas (CO + H 2) at atmospheric pressure. In situ X-ray absorption and photoelectron spectroscopies revealed the oxidation state of the particles as well as the presence of adsorbates under syngas. Transmission electron microscopy was used for ex situ analysis of the shape, elemental composition, and structure after reaction. The original core−shell structure was found to change to a hollow CuCo alloy after pretreatment by oxidation in pure O 2 and reduction in pure H 2. After 30 min of exposure to syngas, a significant fraction (5%) of the particles was strongly depleted in cobalt giving copper-rich nanoparticles. This fraction increased with duration of syngas exposure, a phenomenon that did not occur under pure CO or pure H 2. This study suggests that Co and Cu can each individually contribute to syngas conversion with CuCo catalysts

Analysis of serum proteomics data identifies a quantitative association between beta-defensin 2 at baseline and clinical response to IL-17 blockade in psoriatic arthritis

Objectives Despite several effective targeted therapies, biomarkers that predict whether a patient with psoriatic arthritis (PsA) will respond to a particular treatment are currently lacking.Methods We analysed proteomics data from serum samples of nearly 2000 patients with PsA in placebo-controlled phase-III clinical trials of the interleukin-17 inhibitor secukinumab. To discover predictive biomarkers of clinical response, we used statistical learning with controlled feature selection. The top candidate was validated using an ELISA and was separately assessed in a trial of almost 800 patients with PsA treated with secukinumab or the tumour necrosis factor inhibitor adalimumab.Results Serum levels of beta-defensin 2 (BD-2) at baseline were found to be robustly associated with subsequent clinical response (eg, American College of Rheumatology definition of 20%, 50% and 70% improvement) to secukinumab, but not to placebo. This finding was validated in two independent clinical studies not used for discovery. Although BD-2 is known to be associated with psoriasis severity, the predictivity of BD-2 was independent of baseline Psoriasis Area and Severity Index. The association between BD-2 and response to secukinumab was observed as early as 4 weeks and maintained up to 52 weeks. BD-2 was also found to predict response to treatment with adalimumab. Unlike in PsA, BD-2 was not predictive of response to secukinumab in rheumatoid arthritis.Conclusions In PsA, BD-2 at baseline is quantitatively associated with clinical response to secukinumab. Patients with high levels of BD-2 at baseline reach and sustain higher rates of clinical response after treatment with secukinumab