62 research outputs found
Comparing the Performance of Nb2O5 Composites with Reduced Graphene Oxide and Amorphous Carbon in Liâ and NaâIon Electrochemical Storage Devices
Twoâdimensional (2D) reduced graphene oxide (rGO) is often combined with metal oxides for energyâstorage applications, owing to its unique properties. Here, we compare the electrochemical performance of Nb2O5ârGO and amorphous carbonâcoatedâNb2O5 composites, synthesized in similar conditions. The composite made of Nb2O5 and amorphous carbon (using 1,3,5âtriphenylbenzene as carbon source) outperforms the Nb2O5ârGO counterpart as a high rate anode electrode material in Liâion and Naâion halfâcells and hybrid supercapacitors, delivering specific capacities of 134â
mAhâgâ1 at 25â
C against 98â
mAhâgâ1 for the rGOâbased composite (in Li electrolyte) and 125â
mAhâgâ1 at 20â
C against 98â
mAhâgâ1 (in Na electrolyte). The organic molecules, which are the precursor of the amorphous carbon, control the size and coat the metal oxide particles more efficiently, leading to more extensive carbonâoxide contacts, which benefits the energyâstorage performance.Peer Reviewe
Exploiting the Condensation Reactions of Acetophenone to Engineer Carbon-Encapsulated Nb2O5 Nanocrystals for High-Performance Li and Na Energy Storage Systems
Efficient synthetic methods to produce highâperformance electrodeâactive materials are crucial for developing energy storage devices for largeâscale applications, such as hybrid supercapacitors (HSCs). Here, an effective approach to obtain controllable carbonâencapsulated TâNb2O5 nanocrystals (NCs) is presented, based on the solvothermal treatment of NbCl5 in acetophenone. Two separate condensation reactions of acetophenone generate an intimate and homogeneous mixture of Nb2O5 particles and 1,3,5âtriphenylbenzene (TPB), which acts as a unique carbon precursor. The electrochemical performance of the resulting composites as anode electrode materials can be tuned by varying the Nb2O5/TPB ratio. Remarkable performances are achieved for Liâion and Naâion energy storage systems at high chargeâdischarge rates (specific capacities of â90 mAh gâ1 at 100 C rate for lithium and â125 mAh gâ1 at 20 C for sodium). High energy and power densities are also achieved with Liâ and Naâion HSC devices constructed by using the Nb2O5/C composites as anode and activated carbon (YPFâ50) as cathode, demonstrating the excellent electrochemical properties of the materials synthesized with this approach.Peer Reviewe
Impact of the HIV-1 env Genetic Context outside HR1âHR2 on Resistance to the Fusion Inhibitor Enfuvirtide and Viral Infectivity in Clinical Isolates
Resistance mutations to the HIV-1 fusion inhibitor enfuvirtide emerge mainly within the drug's target region, HR1, and compensatory mutations have been described within HR2. The surrounding envelope (env) genetic context might also contribute to resistance, although to what extent and through which determinants remains elusive. To quantify the direct role of the env context in resistance to enfuvirtide and in viral infectivity, we compared enfuvirtide susceptibility and infectivity of recombinant viral pairs harboring the HR1âHR2 region or the full Env ectodomain of longitudinal env clones from 5 heavily treated patients failing enfuvirtide therapy. Prior to enfuvirtide treatment onset, no env carried known resistance mutations and full Env viruses were on average less susceptible than HR1âHR2 recombinants. All escape clones carried at least one of G36D, V38A, N42D and/or N43D/S in HR1, and accordingly, resistance increased 11- to 2800-fold relative to baseline. Resistance of full Env recombinant viruses was similar to resistance of their HR1âHR2 counterpart, indicating that HR1 and HR2 are the main contributors to resistance. Strictly X4 viruses were more resistant than strictly R5 viruses, while dual-tropic Envs featured similar resistance levels irrespective of the coreceptor expressed by the cell line used. Full Env recombinants from all patients gained infectivity under prolonged drug pressure; for HR1âHR2 viruses, infectivity remained steady for 3/5 patients, while for 2/5 patients, gains in infectivity paralleled those of the corresponding full Env recombinants, indicating that the env genetic context accounts mainly for infectivity adjustments. Phylogenetic analyses revealed that quasispecies selection is a step-wise process where selection of enfuvirtide resistance is a dominant factor early during therapy, while increased infectivity is the prominent driver under prolonged therapy
Les instituteurs et lâinspection primaire
Goubard A. Les instituteurs et lâinspection primaire. In: Manuel gĂ©nĂ©ral de l'instruction primaire : journal hebdomadaire des instituteurs. 60e annĂ©e, tome 29, 1893. pp. 375-376
Effects of repeated organic amendment applications on soil and crop qualities
WOS:000392711300011Soil application of organic waste products (OWP) favors the increase of soil organic matter (SOM) and biological activity, the recycling of nutrients and crop production, but it may also lead to soil contamination. All these effects may occur simultaneously and must be considered in the evaluation of the practice. Various urban composts and manure have been applied every second year in a long-term field experiment during 15 years. A soil sampling assessing the cumulative residual effects of seven applications was used to compare the impact on soil and crop quality of four OWP: a municipal solid waste compost (MSW), a co-compost of sewage sludge and green waste (GWS), a biowaste compost (BIO) and a farmyard manure (FYM). More than 100 different soil indicators were measured (including organic C, N availability, pH, POlsen, plasticity, microbial biomass, enzymatic activity, trace elements and crop yield) and classified in categories to explain soil functioning including crop production: soil fertility, soil biological activity, soil biodiversity, soil physical stability, soil sanitary status (available and total) and crop productivity. Based on these categories, seven minimum data sets (MDS) were defined using statistical analysis, in order to eliminate overlapping parameters and select significant indicators highlighting the effects of OWP compared with a mineral fertilization. The aim of this study was to evaluate the long-term effects of repeated OWP applications on the seven categories of indicators. The OWP were characterized by different qualities and properties of organic matter (OM), which drove their potential effects after application on cropped soils. The GWS and BIO were the most efficient OWP at increasing SOM content, which was one of the major drivers of the effects
Labeling of fibronectin by fluorescent and paramagnetic nanoprobes for exploring the extracellular matrix: bioconjugate synthesis optimization and biochemical characterizatio
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