RESUMEN
Twin boundary (TB) engineering provides exciting opportunities to tune the performance levels of metal-based electrocatalysts. However, the controllable construction of TB greatly relies on surfactants, blocking active sites, and electron transfer by surfactants. Here, a surfactant-free and facile strategy is proposed for synthesizing copper (Cu) nanocatalysts with dense hierarchical TB networks (HTBs) by the rapid thermal reductions in metastable CuO nanosheets in H2 . As revealed by in situ transmission electron microscopy, the formation of HTBs is associated with the fragmentation of nanosheets in different directions to generate abundant crystal nuclei and subsequently unconventional crystal growth through the collision and coalescence of nuclei. Impressively, the HTBs endow Cu with excellent electrocatalytic performance for direct nitrate-ammonia conversion, superior to that of Cu with a single-oriented TB and without TB. It is discovered that the HTBs induce the formation of compressive strains, thereby creating a synergistic effect of TBs and strains to efficiently tune the binding energies of Cu with nitrogen intermediates (i.e., NO2 *) and thus promote the tandem reaction process of NO3 - -to-NO2 - and subsequent NO2 - -to-NH3 electrocatalysis. This work demonstrates the crucial role of HTBs for boosting electrocatalysis via the synergistic effect of TBs and strains.
RESUMEN
Background: Severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) is a tick-borne virus that causes severe communicable fever with thrombocytopenia syndrome (SFTS) with an average case fatality rate of 10%. In the study, we aimed to identify the cross-neutralizing antibody (nAb) against different genotype strains from sera of SFTSV infected patients. Methods: Firstly the genotype of SFTSV was identified by constructing a phylogenetic tree based on the M segments epidemic in the Jiaodong area of Shandong province, then different sera of subjects cross reactive with recombinant Gn (rGn-Fc) or recombinant Gc (rGc-Fc) of 0921 strain were examined. The levels of polyclonal nAbs from sera of 25 convalescents were measured by a pseudovirus-based neutralizing experiment. Results: We found local endemic strains were mainly C2 and C3 isolates of SFTSV. 14 of 15 sera from donors reacted with 0921 rGn-Fc, and 9 of 15 sera from donors reacted with 0921 rGc-Fc. Cross nAbs were produced by 10 of 25 sera from donors during the period of 2019-2021. Among these, five nAbs (A2, A4, A5, L9, and L10) neutralized the pseudoviruses of HB29, Gangwon, HN13, HN20, SPL030A, and SD4 strains. Conclusion: Our data suggested that epidemic strains showed relatively stable heredity. Some blood sources from patients produced cross nAbs that could neutralize all of the strains examined. These findings highlight the important role played by humoral immunity in combatting SFTSV.
