Monoclonal IgG antibodies generated from joint-derived B cells of RA patients have a strong bias toward citrullinated autoantigen recognition

Antibodies targeting citrullinated proteins (ACPAs [anticitrullinated protein antibodies]) are commonly found in patients with rheumatoid arthritis (RA), strongly associate with distinct HLA-DR alleles, and predict a more aggressive disease course as compared with seronegative patients. Still, many features of these antibodies, including their site of production and the extent of MHC class II–driven T cell help, remain unclarified. To address these questions, we have used a single B cell–based cloning technology to isolate and express immunoglobulin (Ig) genes from joint-derived B cells of active RA patients. We found ∼25% of synovial IgG-expressing B cells to be specific for citrullinated autoantigens in the investigated ACPA+ RA patients, whereas such antibodies were not found in ACPA− patients. The citrulline-reactive monoclonal antibodies did not react with the unmodified arginine peptides, yet several reacted with more than one citrullinated antigen. A role for active antigen selection of the citrulline-reactive synovial B cells was supported by the strong bias toward amino acid replacement mutations in ACPA+ antibodies and by their loss of reactivity to citrullinated autoantigens when somatic mutations were reverted to the corresponding germline sequences

Kinetic selection of polymeric guanosine architectures from dynamic supramolecular libraries

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How to modulate catalytic properties in nanosystems: The case of iron-ruthenium nanoparticles

cited By 7International audienceUltrasmall FeRu bimetallic nanoparticles were prepared by co-decomposition of two organometallic precursors, Fe[N(Si(CH3)3) 2]22 and (η4-1,5- cyclooctadiene)(η6-1,3,5-cyclooctatriene)ruthenium(0) (Ru(COD)(COT)), under dihydrogen at 150 °C in mesitylene. A series of FeRu nanoparticles of sizes of approximately 1.8 nm and incorporating different ratios of iron to ruthenium were synthesized by varying the quantity of the ruthenium complex introduced (Fe/Ru=1:1, 1:0.5, 1:0.2, and 1:0.1). FeRu nanoparticles were characterized by TEM, high-resolution TEM, and wide-angle X-ray scattering analyses. Their surface was studied by hydride titration and IR spectroscopy after CO adsorption and their magnetic properties were analyzed by using a superconducting quantum interference device (SQUID). The FeRu nanoparticles were used as catalysts in the hydrogenation of styrene and 2-butanone. The results indicate that the selectivity of the nanoparticle catalysts can be modulated according to their composition and therefore represent a case study on fine-tuning the reactivity of nanocatalysts and adjusting their selectivity in a given reaction. Singing a bimetallic tune: The selectivity of FeRu nanocatalysts in hydrogenation reactions can be tuned by adjusting the Ru content in bimetallic FeRu ultrasmall nanoparticles

Size-Dependent Activity and Selectivity of Fe/MCF-17 in the Catalytic Hydrogenation of Carbon Monoxide Using Fe(0) Nanoparticles as Precursors

International audienceMonodisperse Fe(0) nanoparticles with diameters between 1.8 and 9.0 nm were prepared from organometallic {Fe[N(SiMe3)2]2}2 and intercalated into mesoporous MCF-17 silica. We observed high turnover frequencies of the catalytic CO hydrogenation; they increased with Fe particle size. Methane and short-chain olefin selectivities were highest for small particles, while the opposite trend applied to long-chain terminal olefins and oxygenates. The Anderson–Schulz–Flory chain lengthening probabilities were found to increase with Fe particle size for both paraffins and terminal olefins. Reaction-induced sintering of the metal particles was limited and could be explained by the transformation of Fe(0) precursors into (mainly) Fe-carbides. The results cast new light on the structure sensitivity of the catalytic CO hydrogenation

Electrospray deposition of isolated chemically synthesized magnetic nanoparticles

cited By 2International audienceThe deposition of isolated magnetic nanoparticles onto a substrate was performed using electrohydrodynamic spraying. Two kinds of nanoparticles were sprayed, 11 nm CoFe carbide nanospheres and 10.5 nm Fe nanocubes. By studying carefully the evolution of the sprayed charged droplets and the mechanism of nanoparticle dispersion in them, we could optimize the nanoparticle concentration within the initial nanoparticle solution (i) to reduce the magnetic interaction and therefore prevent agglomeration and (ii) to obtain in a relatively short period (1 h) a deposit of isolated magnetic nanoparticles with a density of up to 400 nanoparticles per µm2. These results open great perspectives for magnetic measurements on single objects using advanced magnetometry techniques as long as spintronics applications based on single chemically synthesized magnetic nanoparticles

Nanoparticle Ripening : A Versatile Approach for the Size and Shape Control of Metallic Iron Nanoparticles

International audienceA novel approach for the synthesis of Fe(0) nanoparticles (NPs) with tunable sizes and shapes is reported. Ultrasmall Fe(0) NPs were reacted under mild conditions in the presence of a mixture of palmitic acid and amine ligands. These NPs acted not only as preformed seeds but also as an internal iron(II) source that was produced by the partial dissolution of the NPs by the acid. This fairly simple approach allows a strict separation between the nucleation and the growth steps. By changing the acid concentration, a fine tuning of the relative ratio between remaining Fe(0) seeds and iron(II) reservoir was achieved, giving access to both size (from 7 to 20 nm) and a shape (spheres, cubes or stars) control. The partial dissolution of the ultrasmall Fe(0) NPs into iron(II) source and the successive growth was further studied by using combined TEM and Mössbauer spectroscopy. The successive corrosion, coalescence, and ripening observed could be understood in the framework of an environment-dependent growth model

Complex Nano-objects Displaying Both Magnetic and Catalytic Properties: A Proof of Concept for Magnetically Induced Heterogeneous Catalysis

International audienceAddition of Co2(Co)9 and Ru3(CO)12 on preformed monodisperse iron(0) nanoparticles (Fe(0) NPs) at 150 °C under H2 leads to monodisperse core–shell Fe@FeCo NPs and to a thin discontinuous Ru(0) layer supported on the initial Fe(0) NPs. The new complex NPs were studied by state-of-the-art transmission electron microscopy techniques as well as X-ray diffraction, Mössbauer spectroscopy, and magnetic measurements. These particles display large heating powers (SAR) when placed in an alternating magnetic field. The combination of magnetic and surface catalytic properties of these novel objects were used to demonstrate a new concept: the possibility of performing Fischer–Tropsch syntheses by heating the catalytic nanoparticles with an external alternating magnetic field

Ceramics from Municipal Waste Incinerator Bottom Ash and Wasted Clay for Sensible Heat Storage at High Temperature

International audienceAlthough work has been done to understand the sintering behavior and properties of Municipal Waste Incinerator Bottom Ashes to produce sintered (Bethanis et al. in Ceram Int 28:881–886, 2002; Cheeseman et al. in Resour Conserv Recycl 43:147–162, 2005; Bourtsalas et al. in Waste Manag 45:217–225, 2014; Taurino et al. in J Eur. Ceram Soc 37:323–331, 2017) or sinter-crystallized (Schabbach et al. in J Non Cryst Solids 357:10–17, 2011; Barbieri et al. in J Non Cryst Solids 354:521–528, 2008) ceramics, most of the trials reported in the literature focuses on the use of extensively milled bottom ashes powders (particle size around 1–50 µm), using processes that might not be easily transferable to industrial production at reasonable cost, and producing small cylinders with uniaxial compression technique on powders. This paper summarizes the development process of an extruded ceramic material made of gross-milled bottom ashes and waste clay, designed to be easily mass-produced using production capacities available in the building bricks industry, to be used as a high-temperature thermal energy storage material, which represents an alternative to the petrurgic ceramic previously developed for this application (Py et al. in J Sol Energy Eng 133:031008, 2011; Kere et al. in Int Conf Eng Waste Biomass Valoris, Porto, 2012; Py et al. in Stockage de l’ énergie: énergie thermique, stockage thermique haute température). Post-treated incinerator bottom ashes from a commercial incinerator has been collected, characterized and processed to form ceramic materials, using clay as a binder. Ashes were milled, dried, and mixed with various amounts of an illitic clay (produced as washing mud by a quartz quarry) prior to extrusion (cylindrical pellet) and firing at different temperatures, ranging from 1100 to 1120 °C. The sintered samples have been characterized in terms of density, mechanical strength, thermal capacity and thermal conductivity. Their mineral structure has also been studied. This work follows a study on the feasibility about the production of MWIBA based slabs with uniaxial compaction, and can be seen as an improvement regarding the shaping of the green bodies, more compatible with thermocline thermal energy storage process. The resulting sintered ceramics exhibit interesting properties such as relatively high mechanical resistance and low thermal conductivity, along with moderate density. These properties allow envisioning the use as filler material for thermocline thermal storage systems, especially considering the simplicity of the production process, relying on dry gross milling (jaw-mill), and firing at a temperature reachable within the building bricks and tiles industry. Production of adequate pieces to be used as thermal storage media seems however more relevant, the small size limiting the impact of sintering heterogeneities (formation of black bodies due to high content in fluxing agents like sodium and potassium)

Development of a Thermal Energy Storage Pressed Plate Ceramic Based on Municipal Waste Incinerator Bottom Ash and Waste Clay

International audiencePressed plates ceramics made of gross-milled bottom ashes and waste clay, were made using technologies available in the building bricks and tiles industry, to ease production upscaling at low-cost. These sintered ceramics are intended for use as a high-temperature thermal energy storage material. They represent an alternative to the waste-based petrurgic ceramics previously developed for this application. Post-treated incinerator bottom ashes from a commercial incinerator were collected, characterized and processed to form ceramic materials, using clay as a binder. Ashes were milled, dried, and mixed with various amounts of an illitic clay (produced as washing mud by a quartz quarry in proportions from 20 to 70% dry weight) prior to uniaxial pressing (12 × 5 × 1 cm slabs) and firing at various temperatures, ranging from 1050 to 1125 °C. The sintered samples have been characterized in terms of volumic mass, mechanical strength, thermal capacity and thermal conductivity. Their mineral structure has also been studied. The resulting sintered ceramics exhibit relatively high mechanical resistance and low thermal conductivity, along with moderate volumic mass. These properties allow envisioning the use as filler material for thermocline thermal storage systems (structured beds), and could be interesting for further work regarding applications in the construction field (bricks, tiles, pavements…)