Polyol-based Synthesis of Praseodymium Oxide Nanoparticles

A series of well-crystallized praseodymium oxide (Pr6O11) nanoparticles are synthesized via a highly scalable process from praseodymium nitrate. Praseodymium hydroxide is synthesized through a modified polyol process and subsequent calcination in air at 600°C for 2 h to transform the precursor material into Pr6O11 nanoparticles. A complete characterization of a specific sample by SEM, HRTEM, and X-ray diffraction (XRD) demonstrates that Pr6O11 nanoparticles form elementary blocks with a calculated size of 118 nm, containing slightly agglomerated nanocrystalline particles with a polycrystalline face-centred cubic phase and an individual size of around 10 nm. Particles can be easily dispersed in water through ultrasonification. Particles display a BET Specific Surface Area (SSA; 8.75 m² g-1) with a nitrogen adsorption-desorption isotherm of type II and a helium density of powders (d = 5.66 g cm-3)

Silica, carbon and boron nitride monoliths with hierarchical porosity prepared by spark plasma sintering process

Silica SBA-15, carbon CMK-3, boron nitride (BN), the latter synthesized from the first two compounds as templates, are mesoporous materials in the form of powders. They have a high specific surface area and an important mesoporous volume. The porosity is organized with the hexagonal symmetric space group p6mm. For selected applications, it could be interesting to preserve these characteristics with materials in a well-defined shape at a macroscopic scale (few millimeters to centimeter). Spark plasma sintering (SPS) is a well-known technique which allows to prepare monoliths with relatively mild conditions. The SPS technique has been used on these mesoporous powders without charge or with a uniaxial charge and at temperatures of 600 °C, 800 °C for silica, 1100 °C, 1300 °C for carbon and 1600 °C, 1700 °C for boron nitride during 1–5 min. The nitrogen adsorption/desorption isotherms reveal that the obtained monoliths present high specific surface area (300–500 m2/g) and important mesoporous volume. The coexistence of interconnected mesoporosity and macroporosity (with volume’s close value) was observed by SEM and TEM, while the XRD and TEM characterization show that the mesoporosity organization is partially preserved

Monolithes de silice et de carbone à porosité hiérarchisée obtenus par frittage SPS

La silice SBA-15 et le carbone CMK-3 possèdent une grande surface spécifique et un volume important de mésopores ordonnés dans une symétrie hexagonale (groupe d’espace p6 mm). Il est nécessaire de préserver leurs caractéristiques lors de la mise en forme de ces matériaux, pour un grand nombre d’applications. Le frittage SPS (Spark Plasma Sintering) des poudres a été effectué sans charge ou avec une charge uniaxiale de 25 MPa et à des températures de 600 à 800 ◦C pour la silice et 1100 à 1300 ◦C pour le carbone, pendant 5 minutes. Les isothermes d’adsorption/désorption d’azote montrent que les monolithes obtenus conservent une surface spécifique élevée (300 à 500 m2/g) et un volume mésoporeux de l’ordre de 0,7 cm3/g. La coexistence de la mésoporosité et d’une macroporosité interconnectée de volume voisin est observée par MEB (Microscopie Électronique à Balayage) et MET (Microscopie Électronique en Transmission). En outre, l’organisation de la mésoporosité est partiellement maintenue comme le mettent en évidence la DRX (Diffraction des Rayons X) et la MET

Improved electrochemical conversion of CO2 to multicarbon products by using molecular doping

The conversion of CO2 into desirable multicarbon products via the electrochemical reduction reaction holds promise to achieve a circular carbon economy. Here, we report a strategy in which we modify the surface of bimetallic silver-copper catalyst with aromatic heterocycles such as thiadiazole and triazole derivatives to increase the conversion of CO2 into hydrocarbon molecules. By combining operando Raman and X-ray absorption spectroscopy with electrocatalytic measurements and analysis of the reaction products, we identified that the electron withdrawing nature of functional groups orients the reaction pathway towards the production of C2+ species (ethanol and ethylene) and enhances the reaction rate on the surface of the catalyst by adjusting the electronic state of surface copper atoms. As a result, we achieve a high Faradaic efficiency for the C2+ formation of approximate to 80% and full-cell energy efficiency of 20.3% with a specific current density of 261.4 mA cm(-2) for C2+ products. Strategies to systematically tune CO2 electroreduction to multicarbon products are of high interests. Here the authors report electron withdrawing functional group alters the reaction pathway towards C2+ products by adjusting the oxidation state of surface copper.D.V., K.Q., and H.L.W. acknowledge funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement no. 804320). L.L., D.V., and H.L.W acknowledge the use of TEM instrumentation provided by the Nation Facility ELECMI ICTS (`Division de Microscopia Electronica', Universidad de Cadiz, DME-UCA). L.L. acknowledges funding from the Andalusian regional government (FEDER-UCA-18-106613), the European Union's Horizon 2020 research and innovation program (grant agreement 823717-ESTEEM3), and the Spanish Ministerio de Economia y Competitividad (PID2019-107578GA-I00). K.Q. and Y.Z. acknowledge financial support from the China Postdoctoral Science Foundation (2018M633127) and the Natural Science Foundation of Guangdong Province (2018A030310602). J.L. acknowledge financial support from the National Natural Science Foundation of China (21808134). We thank Soleil Synchrotron and Andrea Zitolo for allocating beamtime at beamline Samba within the proposal 20200732

Shaping of nanostructured materials or coatings through Spark Plasma Sintering

In the field of advanced ceramics, Spark Plasma Sintering (SPS) is known to be very efficient for superfast and full densification of ceramic nanopowders. This property is attributed to the simultaneous application of high density dc pulsed current and load, even though the sintering mechanisms involved remain unclear. In the first part of the paper, the mechanisms involved during SPS of two insulating oxide nanopowders (Al2O3 and Y2O3) are discussed while in the second part illustrations of the potential of SPS will be given for (i) Consolidation of mesoporous or unstable nanomaterials like SBA-15 or biomimetic apatite, respectively; (ii) Densification of core (BT or BST)/shell (SiO2 or Al2O3) nanoparticles with limited or controlled reaction at the interface. (iii) In-situ preparation of surface-tailored FeœFeAl2O4œAl2O3 nanocomposites, and finally (iv) One-step preparation of multilayer materials like a complete thermal barrier system on single crystal Ni-based superalloy

Shaping of nanostructured materials or coatings through Spark Plasma Sintering

In the field of advanced ceramics, Spark Plasma Sintering (SPS) is known to be very efficient for superfast and full densification of ceramic nanopowders. This property is attributed to the simultaneous application of high density dc pulsed current and load, even though the sintering mechanisms involved remain unclear. In the first part of the paper, the mechanisms involved during SPS of two insulating oxide nanopowders (Al2O3 and Y2O3) are discussed while in the second part illustrations of the potential of SPS will be given for (i) Consolidation of mesoporous or unstable nanomaterials like SBA-15 or biomimetic apatite, respectively; (ii) Densification of core (BT or BST)/shell (SiO2 or Al2O3) nanoparticles with limited or controlled reaction at the interface. (iii) In-situ preparation of surface-tailored FeœFeAl2O4œAl2O3 nanocomposites, and finally (iv) One-step preparation of multilayer materials like a complete thermal barrier system on single crystal Ni-based superalloy

A phase I study of the oral gamma secretase inhibitor R04929097 in combination with gemcitabine in patients with advanced solid tumors (PHL-078/CTEP 8575)

PURPOSE: To establish the recommended phase II dose of the oral γ-secretase inhibitor RO4929097 (RO) in combination with gemcitabine; secondary objectives include the evaluation of safety, tolerability, pharmacokinetics, biomarkers of Notch signaling and preliminary anti-tumor activity. METHODS: Patients with advanced solid tumors were enrolled in cohorts of escalating RO dose levels (DLs). Tested RO DLs were 20 mg, 30 mg, 45 mg and 90 mg. RO was administered orally, once daily on days 1-3, 8-10, 15-17, 22-24. Gemcitabine was administered at 1,000 mg/m(2) on d1, 8, and 15 in 28 d cycles. Dose limiting toxicities (DLTs) were assessed by CTCAE v4. Serial plasma was collected for RO (total and unbound) and gemcitabine pharmacokinetic analysis. Biomarkers of Notch signaling were assessed by immunohistochemistry in archival tissue. Antitumor activity was evaluated (RECIST 1.1). RESULTS: A total of 18 patients were enrolled to establish the recommended phase II dose. Of these, 3 patients received 20 mg RO, 7 patients received 30 mg RO, 6 patients received 45 mg RO and 2 patients received 90 mg RO. DLTs were grade 3 transaminitis (30 mg RO), grade 3 transaminitis and maculopapular rash (45 mg RO), and grade 3 transaminitis and failure to receive 75 % of planned RO doses secondary to prolonged neutropenia (90 mg); all were reversible. The maximum tolerated dose was exceeded at 90 mg RO. Pharmacokinetic analysis of both total and free RO confirmed the presence of autoinduction at 45 and 90 mg. Median levels of Notch3 staining were higher in individuals who received fewer than 4 cycles (p = 0.029). Circulating angiogenic factor levels did not correlate with time to progression or ≥ grade 3 adverse events. Best response (RECIST 1.1) was partial response (nasopharyngeal cancer) and stable disease > 4 months was observed in 3 patients (pancreas, tracheal, and breast primary cancers). CONCLUSIONS: RO and gemcitabine can be safely combined. The recommended phase II dose of RO was 30 mg in combination with gemcitabine 1,000 mg/m(2). Although RO exposure was limited by the presence of autoinduction, RO levels achieved exceeded the area under the concentration-time curve for 0-24 h (AUC(0-24)) predicted for efficacy in preclinical models using daily dosing. Evidence of clinical antitumor activity and prolonged stable disease were identified

Optical properties of ZnO deposited by atomic layer deposition (ALD) on Si nanowires

International audienceIn this work, we report proof-of-concept results on the synthesis of Si core/ ZnO shell nanowires (SiNWs/ZnO) by combining nanosphere lithography (NSL), metal assisted chemical etching (MACE) and atomic layer deposition (ALD). The structural properties of the SiNWs/ZnO nanostructures prepared were investigated by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies. The X-ray diffraction analysis revealed that all samples have a hexagonal wurtzite structure. The grain sizes are found to be in the range of 7-14 nm. The optical properties of the samples were investigated using reflectance and photoluminescence spectroscopy. The study of photoluminescence (PL) spectra of SiNWs/ZnO samples showed the domination of defect emission bands, pointing to deviations of the stoichiometry of the prepared 3D ZnO nanostructures. Reduction of the PL intensity of the SiNWs/ZnO with the increase of SiNWs etching time was observed, depicting an advanced light scattering with the increase of the nanowire length. These results open up new prospects for the design of electronic and sensing devices

Disease-Causing 7.4 kb Cis-Regulatory Deletion Disrupting Conserved Non-Coding Sequences and Their Interaction with the FOXL2 Promotor: Implications for Mutation Screening

To date, the contribution of disrupted potentially cis-regulatory conserved non-coding sequences (CNCs) to human disease is most likely underestimated, as no systematic screens for putative deleterious variations in CNCs have been conducted. As a model for monogenic disease we studied the involvement of genetic changes of CNCs in the cis-regulatory domain of FOXL2 in blepharophimosis syndrome (BPES). Fifty-seven molecularly unsolved BPES patients underwent high-resolution copy number screening and targeted sequencing of CNCs. Apart from three larger distant deletions, a de novo deletion as small as 7.4 kb was found at 283 kb 5′ to FOXL2. The deletion appeared to be triggered by an H-DNA-induced double-stranded break (DSB). In addition, it disrupts a novel long non-coding RNA (ncRNA) PISRT1 and 8 CNCs. The regulatory potential of the deleted CNCs was substantiated by in vitro luciferase assays. Interestingly, Chromosome Conformation Capture (3C) of a 625 kb region surrounding FOXL2 in expressing cellular systems revealed physical interactions of three upstream fragments and the FOXL2 core promoter. Importantly, one of these contains the 7.4 kb deleted fragment. Overall, this study revealed the smallest distant deletion causing monogenic disease and impacts upon the concept of mutation screening in human disease and developmental disorders in particular