Engineering oxygen vacancies in mesoporous TiO2 effectively enhanced its ability to trap polysulfides and simultaneously propelled the redox conversion of polysulfides.

Despite their high-energy density, low cost and environmental friendliness, the commercial application of lithium-sulfur batteries (LSBs) has been plagued by their severe capacity decay during long-term cycling caused by polysulfide shuttling. Herein, we demonstrate a synergetic vacancy and heterostructure engineering strategy using a nitrogen-doped graphene/SnS2/TiO2 (denoted as NG/SnS2/TiO2) nanocomposite to enhance the electrochemical performance of LSBs. It is noted that plentiful sulfur vacancy (Vs) defects and nanosized heterojunctions are created on the NG/SnS2/TiO2 composite as proved using electron paramagnetic resonance, transmission electron microscopy and X-ray photoelectron spectroscopy, which can serve as strong adsorption and activation sites for polar polysulfide intermediates, prevent their dissolution/shuttling, and accelerate their redox reaction. The novel NG/SnS2/TiO2-S cathode delivers a high initial capacity of 1064 mA h g-1 at 0.5 C and a high capacity retention rate of 68% after 500 cycles at 0.5 C.

Photoclickable fluorogenic probes will enable visualization of specific biomolecules with precise spatiotemporal control in their native environment. However, the fluorogenic tagging of DNA with current photocontrolled clickable probes is still challenging. Herein, we demonstrated the fast (19.5 ± 2.5 M −1 s −1 ) fluorogenic labeling and imaging of DNA in vitro and in vivo with rationally designed coumarin-fused tetrazoles under UV LED photoirradiation. With a water-soluble, nuclear-specific coumarin-fused tetrazole (CTz-SO 3 ), the metabolically synthesized DNA in cultured cells was effectively labeled and visualized, without fixation, via "photoclick" reaction. Moreover, the photoclickable CTz-SO 3 enabled real-time, spatially controlled imaging of DNA in live zebrafish.

Ginsenosides are considered the major constituents that are responsible for most of the pharmacological actions of ginseng. However, some ginsenosides exist as stereoisomeric pairs, detailed and molecular exposition based on the structural differences of ginsenoside stereoisomers has not been emphasized in most studies. Here we explore the functional differences of ginsenoside Rg₃ stereoisomers on angiogenesis. In this study, we demonstrated the distinctive differential angiogenic activities of 20(S)-Rg₃ and 20(R)-Rg₃ stereoisomers. 20(S)-Rg₃ at micromolar concentration promotes human endothelial cells proliferation, migration and tube formation in vitro, as well as ex vivo endothelial sprouting. The effects induced by 20(S)-Rg₃ are significantly more potent than 20(R)-Rg₃. These effects are partially mediated through the activation of AKT/ERK-eNOS signaling pathways. Moreover, knockdown of peroxisome proliferator-activated receptor-gamma (PPARγ) by specific small interference RNA abolished the 20(S)-Rg₃-induced angiogenesis, indicating that PPARγ is responsible for mediating the angiogenic activity of Rg₃. Using reporter gene assay, the PPARγ agonist activity of 20(S)-Rg₃ has been found 10-fold higher than that of 20(R)-Rg₃. Computer modeling also revealed the differential binding is due to the chiral center of 20(S)-Rg₃ can form a critical hydrogen bond with Tyr473 of PPARγ ligand binding domain. The present study elucidated the differential angiogenic effects of Rg₃ stereoisomers by acting as agonist of PPARγ. The results shed light on the structural difference between two ginsenoside stereoisomers that can lead to significant differential physiological outcomes which should be carefully considered in the future development of ginsenoside-based therapeutics.

The content of oxygen vacancy, as the intercalation places of oxygen during the oxygen ion intercalation process, has a significant influence on the electrochemical properties of the perovskite pseudocapacitance. To enhance the electrochemical performance of perovskite supercapacitors, we propose a novel strategy of the plasma etching technique to improve the oxygen vacancy concentration of the LaCoO3 electrode. The influence of plasma composition and etching time on the etching effect was investigated. Results show that the etching effect of H2 is better than that of Ar. The specific capacitance of the LaCoO3 electrode etched for 5 min in 10 sccm H2 and 90 sccm Ar increased from 339.8 F g–1 to 706.9 F g–1. The asymmetric supercapacitor assembled with graphene oxide delivers a high energy density of 47.64 Wh kg–1 at a power density of 804.4 W kg–1 and still maintains 35.02 Wh kg–1 at a high power density of 37 080 W kg–1. After 4000 cycles at 5 A g–1, there is little degradation of specific capacitance with the Coulombic efficiency maintaining a high level of 96%. It can be concluded that the plasma etching technique is an efficient way to improve the energy storage performance of perovskite pseudocapacitive materials.