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Although theoretical calculations predict vanadium carbide (V2C) MXene may possess superior performances as electrodes of supercapacitors and lithium-ion batteries, a milder synthesis process of high-purity V2C MXene undoubtedly becomes one of the greatest hindrances for extending its applications. Herein, we report a hydrofluoric acid (HF)-free synthesis of 2D V2C MXene by milder etching V2AlC powders in the mixture of lithium fluoride and hydrochloric acid. The etching time plays vital roles on the structure and morphology of V2C MXene. The as-synthesized V2C MXene etched for 120 h displays a uniform multilayered structure and higher purity (>90%). All that matter is it exhibits a maximum specific capacitance of 164 F g−1 at a scan rate of 2 mV s−1, good cycling stability and high specific capacitance retention (~90% after 10 000 cycles at 5 A g−1) in 1 M Na2SO4 electrolyte. Moreover, other fluorides, including potassium fluoride, sodium fluoride and ammonium hydrogen fluoride, are also testified to be effective to obtain highly pure V2C MXene. This work provides the certainty for synthesizing MXenes besides Ti3C2 via a HF-free etching process to beneficially expand their promising application.

Ovomucin, accounting for w3.5% of total egg white protein, is responsible for the thick gel characteristics of liquid egg white. Besides its excellent foaming and emulsion capacities, it possesses anti-viral, anti-bacterial, anti-tumor and other bioactivities. This paper reviews compositional, structural, physicochemical, functional and biological properties of ovomucin, as well as development of methods of extraction. As one of the least defined proteins in egg white, further study is required to characterize the structure and to explore its full potential in new applications as functional foods and nutraceuticals.

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For conventional polycrystalline Ni‐rich cathode material consisting of numerous primary particles in disordered orientation, the crystal anisotropy in charge/discharge process results in the poor rate capability and rapid capacity degradation. In this work, highly‐dispersed submicron single‐crystal LiNi0.8Co0.15Al0.05O2 (SC‐NCA) cathode is efficiently prepared by spray pyrolysis (SP) technique followed by a simple solid‐state lithiation reaction. Porous Ni0.8Co0.15Al0.05Ox precursor prepared via SP exhibits high chemical activity for lithiation reaction, enabling the fabrication of single‐crystal cathode at a relatively low temperature. In this way, the contradiction between high crystallinity and cation disordering is well balanced. The resulted optimized SC‐NCA shows polyhedral single‐crystal morphology with moderate grain size (≈1 μm), which are beneficial to shortening the Li+ diffusion path and improving the structural stability. As cathode for lithium ion batteries, SC‐NCA delivers a high discharge capacity of 202 and 140 mAh g−1 at 0.1 and 10 C, respectively, and maintains superior capacity retention of 161 mAh g−1 after 200 cycles at 1C. No micro‐crack is observed in the cycled SC‐NCA particles, indicating such single‐crystal morphology can greatly relieve the anisotropic micro‐strain. This effective, continuous and adaptable strategy for preparing single‐crystal Ni‐rich cathode without any additive may accelerate their practical application.

Background Hepatitis B virus covalently closed circular DNA (HBV cccDNA) is assembled by histones and non-histones into a chromatin-like cccDNA minichromosome in the nucleus. The cellular histone acetyltransferase GCN5, displaying succinyltransferase activity, is recruited onto cccDNA to modulate HBV transcription in cells. Clinically, IFN-α is able to repress cccDNA. However, the underlying mechanism of IFN-α in the depression of cccDNA mediated by GCN5 is poorly understood. Here, we explored the effect of IFN-α on GCN5-mediated succinylation in the epigenetic regulation of HBV cccDNA minichromosome. Results Succinylation modification of the cccDNA minichromosome has been observed in HBV-infected human liver-chimeric mice and HBV-expressing cell lines. Moreover, histone H3K79 succinylation by GCN5 was identified in the system. Interestingly, the mutant of histone H3K79 efficiently blocked the replication of HBV, and interference with GCN5 resulted in decreased levels of HBV DNA, HBsAg, and HBeAg in the supernatant from de novo HBV-infected HepaRG cells. Consistently, the levels of histone H3K79 succinylation were significantly elevated in the livers of HBV-infected human liver-chimeric mice. The knockdown or overexpression of GCN5 or the mutant of GCN5 could affect the binding of GCN5 to cccDNA or H3K79 succinylation, leading to a change in cccDNA transcription activity. In addition, Southern blot analysis validated that siGCN5 decreased the levels of cccDNA in the cells, suggesting that GCN5-mediated succinylation of histone H3K79 contributes to the epigenetic regulation of cccDNA minichromosome. Strikingly, IFN-α effectively depressed histone H3K79 succinylation in HBV cccDNA minichromosome in de novo HepG2-NTCP and HBV-infected HepaRG cells. Conclusions IFN-α epigenetically regulates the HBV cccDNA minichromosome by modulating GCN5-mediated succinylation of histone H3K79 to clear HBV cccDNA. Our findings provide new insights into the mechanism by which IFN-α modulate the epigenetic regulation of HBV cccDNA minichromosome.

Egg proteins are recognized as excellent sources of bioactive peptides, such as angiotensin-converting enzyme inhibitory (ACEi) peptides. Oral administration of a thermolysin-digested egg white hydrolysate (T-EWH) caused a significant blood pressure reduction in spontaneously hypertensive rats; a further ACEi assay implied that its ACEi activity was enhanced after in vitro gastrointestinal (GI) digestion. These results indicated that T-EWH contained ACEi peptides resisting GI digestion and/or being further released during GI digestion. Therefore, the objective of this study was to identify these responsible ACEi peptides from T-EWH. The conventionally activity-guided fractionation was applied, coupled with a synchronized GI digestion throughout, during which both peptide yield and ACEi activity before and after the GI digestion were measured. Finally, six ACEi peptides (LAPYK, LKISQ, LKYAT, INKVVR, LFLIKH, and LGHWVY) with good GI resistance were identified with IC50 values <20 μM, especially LKYAT (0.09 μM). The structure–activity relationship of these peptides was discussed. The discovery of GI-resistant ACEi peptides could further support the application of egg white proteins as functional food ingredients.

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