Aqueous zinc (Zn) batteries (AZBs) are widely considered as a promising candidate for next‐generation energy storage owing to their excellent safety features. However, the application of a Zn anode is hindered by severe dendrite formation and side reactions. Herein, an interfacial bridged organic–inorganic hybrid protection layer (Nafion‐Zn‐X) is developed by complexing inorganic Zn‐X zeolite nanoparticles with Nafion, which shifts ion transport from channel transport in Nafion to a hopping mechanism in the organic–inorganic interface. This unique organic–inorganic structure is found to effectively suppress dendrite growth and side reactions of the Zn anode. Consequently, the Zn@Nafion‐Zn‐X composite anode delivers high coulombic efficiency (ca. 97 %), deep Zn plating/stripping (10 mAh cm−2), and long cycle life (over 10 000 cycles). By tackling the intrinsic chemical/electrochemical issues, the proposed strategy provides a versatile remedy for the limited cycle life of the Zn anode.
Ion selective separators with the capability of conducting lithium ion and blocking polysulfides are critical and highly desired for high-performance lithium−sulfur (Li−S) batteries. Herein, we fabricate an ion selective film of covalent organic framework (denoted as TpPa-SO 3 Li) onto the commercial Celgard separator. The aligned nanochannels and continuous negatively charged sites in the TpPa-SO 3 Li layer can effectively facilitate the lithium ion conduction and meanwhile significantly suppress the diffusion of polysulfides via the electrostatic interaction. Consequently, the TpPa-SO 3 Li layer exhibits excellent ion selectivity with an extremely high lithium ion transference number of 0.88. When using this novel functional layer, the Li−S batteries with a high sulfur loading of 5.4 mg cm −2 can acquire a high initial capacity of 822.9 mA h g −1 and high retention rate of 78% after 100 cycles at 0.2 C. This work provides new insights into developing high-performance Li−S batteries via ion selective separator strategy.
Aspergillus flavus first gained scientific attention for its production of aflatoxin. The underlying regulation of aflatoxin biosynthesis has been serving as a theoretical model for biosynthesis of other microbial secondary metabolites. Nevertheless, for several decades, the DNA methylation status, one of the important epigenomic modifications involved in gene regulation, in A. flavus remains to be controversial. Here, we applied bisulfite sequencing in conjunction with a biological replicate strategy to investigate the DNA methylation profiling of A. flavus genome. Both the bisulfite sequencing data and the methylome comparisons with other fungi confirm that the DNA methylation level of this fungus is negligible. Further investigation into the DNA methyltransferase of Aspergillus uncovers its close relationship with RID-like enzymes as well as its divergence with the methyltransferase of species with validated DNA methylation. The lack of repeat contents of the A. flavus' genome and the high RIP-index of the small amount of remanent repeat potentially support our speculation that DNA methylation may be absent in A. flavus or that it may possess de novo DNA methylation which occurs very transiently during the obscure sexual stage of this fungal species. This work contributes to our understanding on the DNA methylation status of A. flavus, as well as reinforces our views on the DNA methylation in fungal species. In addition, our strategy of applying bisulfite sequencing to DNA methylation detection in species with low DNA methylation may serve as a reference for later scientific investigations in other hypomethylated species.
The use of artificial cornea implants has received increasing attention for treating cornea-related diseases and vision errors due to the low side effects. To achieve long-term successful vision correction, stable and biocompatible materials of high refractive index (RI) need to be developed. Herein, we developed an interpenetrating polymer network (IPN) hydrogel containing well-dispersed ZnS nanoparticles (∼3 nm) covalently linked to the first polymer network, poly(2-hydroethyl methacrylate) (PHEMA). The second polymer network used was poly(acrylic acid) (PAA). The resultant ZnS/PHEMA/PAA IPN nanocomposite is clear and transparent at both dry and hydrated states with their RIs measured to be as high as 1.65 and 1.49, respectively. The equilibrium water content of the hydrogel nanocomposite reached 60.2% which is reasonably near to that of cornea. The material exerted minimal cytotoxicity toward primary epidermal keratinocyte cells. The high RI IPN hydrogel nanocomposite developed here might be an excellent candidate for artificial cornea implants.
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