Thermochemical Route for Extraction and Recycling of Critical, Strategic and High Value Elements from By-Products and End-of-Life Materials, Part I: Treatment of a Copper By-Product in Air Atmosphere

Development of our modern society requests a number of critical and strategic elements (platinum group metals, In, Ga, Ge…) and high value added elements (Au, Ag, Se, Te, Ni…) which are often concentrated in by-products during the extraction of base metals (Cu, Pb, Zn…). Further, recycling of end-of-life materials employed in high technology, renewable energy and transport by conventional extractive processes also leads to the concentration of such chemical elements and their compounds in metallurgical by-products and/or co-products. One of these materials, copper anode slime (CAS), derived from a copper electrolytic refining factory, was used for this study. The sample was subjected to isothermal treatment from 225 to 770 °C under air atmosphere and the reaction products were systematically analyzed by scanning electron microscopy through energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) to investigate the thermal behavior of the treated sample. The main components of the anode slime (CuAgSe, Cu2-xSeyS1-y, Ag3AuSe2) react with oxygen, producing mostly copper and selenium oxides as well as Ag-Au alloys as final products at temperatures higher than 500 °C. Selenium dioxide (SeO2) is volatilized and recovered in pure state by cooling the gaseous phase, whilst copper(II) oxide, silver, gold and tellurium remain in the treatment residue

Association de la DRX au MEB/EDX pour caractériser l’évolution des porteurs de métaux lors du traitement thermique des boues anodiques de cuivre

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Thermochemical Route for Extraction and Recycling of Critical, Strategic and High-Value Elements from By-Products and End-of-Life Materials, Part II: Processing in Presence of Halogenated Atmosphere

International audienceDuring the treatment of copper anode slime (CAS) under an air atmosphere, several aspects of the interactions of its main components (CuAgSe, Cu2−xSeyS1−y, Ag3AuSe2) with oxygen were described in Part I. As a comparative and complementary study, this work deals with the thermal behavior of CAS under air in the presence of polyvinyl chloride (PVC) between 195 and 770 °C. The preliminary thermal treatment of an e-waste sample containing brominated substances was also performed. The reaction products were systematically analyzed by scanning electron microscopy through energy-dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) to investigate the thermal behaviors of the studied samples in a halogenated medium. At low temperatures, the copper, silver and selenium compounds of the CAS reacted with the HCl, issued from PVC degradation, leading to the formation of their respective chlorides. Bromides of valuable metals (Cu, Pb, Sn…) were synthesized during the e-waste treatment at 500 °C and they were distributed between the solid residue and gaseous phase. The data obtained give an insight into the reactivity of several metals towards halogenated substances, which may be valuable information for conducting the extraction and recycling of targeted elements from industrial by-products and end-of-life materials by a thermochemical route

Fluorescent peptide biosensor for probing CDK6 activity in lung cancer cell extracts

International audienceCDK6 kinase regulates cell cycle progression in G1, together with CDK4, but has cell-, tissue- and developmentally-distinct functions associated with transcription, angiogenesis and metabolism. Although CDK6 constitutes an attractive cancer biomarker and target there are no means of assessing its activity in a complex environment. In this study we describe design, engineering and characterization of a fluorescent peptide biosensor derived from 6-phosphofructokinase that reports on CDK6 kinase activity through sensitive changes in fluorescence intensity. This biosensor can report on CDK6 activity in a dose-dependent fashion, thereby enabling quantification of differences in kinase activity in complex and physiologically-relevant environments. Further implementation of this biosensor in different lung and melanoma cell lines, as well as in mesothelioma cell lines derived from patients together with a CDK4 biosensor highlighted differences in kinase activity between CDK6 and CDK4 kinase. This work demonstrates the utility of these selective tools for monitoring two closely related kinases comparatively and simultaneously in the same samples, thereby offering attractive perspectives for diagnostic and therapeutic purposes

Evaluation of the ability of linezolid and tedizolid to eradicate intraosteoblastic and biofilm-embedded Staphylococcus aureus in the bone and joint infection setting

Objectives: Prolonged use of linezolid for bone and joint infection (BJI) is limited by its long-term toxicity. The better safety profile of tedizolid, a recently developed oxazolidinone, could offer an alternative. However, its efficacy against biofilm-embedded and intracellular Staphylococcus aureus, the two main bacterial reservoirs associated with BJI chronicity, is unknown.Methods: Using three S. aureus strains (6850 and two clinical BJI isolates), linezolid and tedizolid were compared regarding their ability: (i) to target the S. aureus intracellular reservoir in an in vitro model of osteoblast infection, using three concentrations increasing from the bone concentration reached with standard therapeutic doses (Cbone = 2.5 × MIC; Cplasm = 10 × MIC; Cmax = 40 × MIC); (ii) to eradicate mature biofilm [minimal biofilm eradication concentration (MBEC)]; and (iii) to prevent biofilm formation [biofilm MIC (bMIC) and confocal microscopy].Results: Linezolid and tedizolid weakly reduced the intracellular inoculum of S. aureus in a strain-dependent manner despite the similar MICs for the tested strains, but improved cell viability even in the absence of an intracellular bactericidal effect. Conversely, linezolid and tedizolid were ineffective in eradicating mature biofilm formed in vitro, with MBEC >2000 and >675?mg/L, respectively. bMICs of tedizolid were 4-fold lower than those of linezolid for all strains.Conclusions: Linezolid and tedizolid alone are not optimal candidates to target bacterial phenotypes associated with chronic forms of BJI. Despite weak intracellular activity, they both reduce infection-related cytotoxicity, suggesting a role in modulating intracellular expression of staphylococcal virulence factors. Although inactive against biofilm-embedded S. aureus, both-but particularly tedizolid-are able to prevent biofilm formation

Bone and Joint Infection Involving Corynebacterium spp.: From Clinical Features to Pathophysiological Pathways

Introduction: Corynebacteria represent often-neglected etiological agents of post-traumatic and/or post-operative bone and joint infection (BJI). We describe here clinical characteristics and bacteriological determinants of this condition. Methods: A retrospective cohort study described characteristics, outcome and determinants of treatment failure of all patients with proven Corynebacterium spp. BJI (i.e., ?2 culture-positive gold-standard samples). Available strains were further characterized regarding their antibiotic susceptibilies, abilities to form early (BioFilm Ring Test®) and mature (crystal violet staining method) biofilms and to invade osteoblasts (gentamicin protection assay). Results: The 51 included BJI were mostly chronic (88.2%), orthopedic device-related (74.5%) and polymicrobial (78.4%). After a follow-up of 60.7 weeks (IQR, 30.1-115.1), 20 (39.2%) treatment failures were observed, including 4 Corynebacterium-documented relapses, mostly associated with non-optimal surgical management (OR 7.291; p = 0.039). Internalization rate within MG63 human osteoblasts was higher for strains isolated from delayed (>3 months) BJI (p < 0.001). Infection of murine osteoblasts deleted for the ?1-integrin resulted in a drastic reduction in the internalization rate. No difference was observed regarding biofilm formation. Conclusions: Surgical management plays a crucial role in outcome of BJI involving corynebacteria, as often chronic and device-associated infections. Sanctuarisation within osteoblasts, implicating the ?1 cellular integrin, may represent a pivotal virulence factor associated with BJI chronicity

Lysosomal alkalization to potentiate eradication of intra-osteoblastic Staphylococcus aureus in the bone and joint infection setting

OBJECTIVES: Beyond intracellular penetration, acidic lysosomal pH might affect the intracellular activity of some antimicrobials. This study evaluated the ability of lysosomotropic alkalizing agents to potentiate the antimicrobial eradication of an intra-osteoblastic Staphylococcus aureus reservoir in the setting of bone and joint infection (BJI).METHODS: MICs of 16 anti-staphylococcal molecules active against methicillin-sensitive S.aureus (MSSA) were evaluated at pH 5 and pH 7. Additionally, the lysosomal alkalizing potential (spectrofluorometry) and cytotoxicity (MTT assay) of hydroxychloroquine, amantadine and ammonium chloride were assessed. The results led to further investigation of clindamycin, cotrimoxazole, daptomycin and levofloxacin-alone or in combination with hydroxychloroquine-in an invitro model of osteoblast infection. The impact of hydroxychloroquine on autophagy was finally investigated using Western blot detection of two autophagic flux indicators, the LC3 membrane protein and the SQSTM1 cargo protein.RESULTS: Daptomycin, cotrimoxazole, clindamycin and levofloxacin alone significantly decreased the intracellular staphylococcal reservoir (5.12 log10CFU/100000cells) by 0.14 (95%CI 0.01-0.34), 0.25 (95%CI 0.12-0.43), 0.16 (95%CI 0.004-0.39) and 1.18 (95%CI 1.04-1.38) log10CFU/100000cells, respectively (

Lysosomal alkalization to potentiate eradication of intra-osteoblastic Staphylococcus aureus in the bone and joint infection setting

OBJECTIVES: Beyond intracellular penetration, acidic lysosomal pH might affect the intracellular activity of some antimicrobials. This study evaluated the ability of lysosomotropic alkalizing agents to potentiate the antimicrobial eradication of an intra-osteoblastic Staphylococcus aureus reservoir in the setting of bone and joint infection (BJI).METHODS: MICs of 16 anti-staphylococcal molecules active against methicillin-sensitive S.aureus (MSSA) were evaluated at pH 5 and pH 7. Additionally, the lysosomal alkalizing potential (spectrofluorometry) and cytotoxicity (MTT assay) of hydroxychloroquine, amantadine and ammonium chloride were assessed. The results led to further investigation of clindamycin, cotrimoxazole, daptomycin and levofloxacin-alone or in combination with hydroxychloroquine-in an invitro model of osteoblast infection. The impact of hydroxychloroquine on autophagy was finally investigated using Western blot detection of two autophagic flux indicators, the LC3 membrane protein and the SQSTM1 cargo protein.RESULTS: Daptomycin, cotrimoxazole, clindamycin and levofloxacin alone significantly decreased the intracellular staphylococcal reservoir (5.12 log10CFU/100000cells) by 0.14 (95%CI 0.01-0.34), 0.25 (95%CI 0.12-0.43), 0.16 (95%CI 0.004-0.39) and 1.18 (95%CI 1.04-1.38) log10CFU/100000cells, respectively (

Lysosomal alkalization to potentiate eradication of intra-osteoblastic Staphylococcus aureus in the bone and joint infection setting

OBJECTIVES: Beyond intracellular penetration, acidic lysosomal pH might affect the intracellular activity of some antimicrobials. This study evaluated the ability of lysosomotropic alkalizing agents to potentiate the antimicrobial eradication of an intra-osteoblastic Staphylococcus aureus reservoir in the setting of bone and joint infection (BJI).METHODS: MICs of 16 anti-staphylococcal molecules active against methicillin-sensitive S.aureus (MSSA) were evaluated at pH 5 and pH 7. Additionally, the lysosomal alkalizing potential (spectrofluorometry) and cytotoxicity (MTT assay) of hydroxychloroquine, amantadine and ammonium chloride were assessed. The results led to further investigation of clindamycin, cotrimoxazole, daptomycin and levofloxacin-alone or in combination with hydroxychloroquine-in an invitro model of osteoblast infection. The impact of hydroxychloroquine on autophagy was finally investigated using Western blot detection of two autophagic flux indicators, the LC3 membrane protein and the SQSTM1 cargo protein.RESULTS: Daptomycin, cotrimoxazole, clindamycin and levofloxacin alone significantly decreased the intracellular staphylococcal reservoir (5.12 log10CFU/100000cells) by 0.14 (95%CI 0.01-0.34), 0.25 (95%CI 0.12-0.43), 0.16 (95%CI 0.004-0.39) and 1.18 (95%CI 1.04-1.38) log10CFU/100000cells, respectively (