Atomically Precise Copper Nanoclusters for Highly Efficient Electroreduction of CO2 towards Hydrocarbons via Breaking the Coordination Symmetry of Cu Site.

We propose an effective highest occupied d-orbital modulation strategy engendered by breaking the coordination symmetry of sites in the atomically precise Cu nanocluster (NC) to switch the product of CO2 electroreduction from HCOOH/CO to higher-valued hydrocarbons. An atomically well-defined Cu6 NC with symmetry-broken Cu-S2 N1 active sites (named Cu6 (MBD)6 , MBD=2-mercaptobenzimidazole) was designed and synthesized by a judicious choice of ligand containing both S and N coordination atoms. Different from the previously reported high HCOOH selectivity of Cu NCs with Cu-S3 sites, the Cu6 (MBD)6 with Cu-S2 N1 coordination structure shows a high Faradaic efficiency toward hydrocarbons of 65.5 % at -1.4 V versus the reversible hydrogen electrode (including 42.5 % CH4 and 23 % C2 H4 ), with the hydrocarbons partial current density of -183.4 mA cm-2 . Theoretical calculations reveal that the symmetry-broken Cu-S2 N1 sites can rearrange the Cu 3d orbitals with d x 2 - y 2 ${d_{x^2 - y^2 } }$ as the highest occupied d-orbital, thus favoring the generation of key intermediate *COOH instead of *OCHO to favor *CO formation, followed by hydrogenation and/or C-C coupling to produce hydrocarbons. This is the first attempt to regulate the coordination mode of Cu atom in Cu NCs for hydrocarbons generation, and provides new inspiration for designing atomically precise NCs for efficient CO2 RR towards highly-valued products.

Real-Time Fluorescent Monitoring of Kinetically Controlled Supramolecular Self-Assembly of Atom-Precise Cu8 Nanocluster.

Kinetically stable and long-lived intermediates are crucial in monitoring the progress and understanding of supramolecular self-assembly of diverse aggregated structures with collective functions. Herein, the complex dynamics of an atomically precise CuI nanocluster [Cu8 (t BuC6 H4 S)8 (PPh3 )4 ] (Cu8a) is systematically investigated. Remarkably, by monitoring the aggregation-induced emission (AIE) and electron microscopy of the kinetically stable intermediates in real time, the directed self-assembly (DSA) process of Cu8a is deduced. The polymorphism and different emission properties of Cu NCs aggregates were successfully captured, allowing the structure-optical property relationship to be established. More importantly, the utilization of a mathematical "permutation and combination" ideology by introducing a heterogeneous luminescent agent of a carbon dot (CD) to Cu8a aggregates enriches the "visualization" fluorescence window, which offers great potential in real time application for optical sensing of materials.

Self-assembly of an alkynylpyrene derivative for multi-responsive fluorescence behavior and photoswitching performance.

Highly emissive fluorophores based on polyaromatic hydrocarbons with tunable emission properties and aggregated structures play a very important role in relevant functional studies. In this study, a novel alkynylpyrene derivative 1 was synthesized, which exhibits unimolecular to excimer emission in methanol with an increasing concentration accompanied by the formation of nanovesicles via the π-π stacking, hydrogen bond and hydrophobic interaction. The self-assembly behavior as well as emission properties of 1 in aprotic polar solvents (ACN, acetone, DMF and DMSO) can also be adjusted by the volume fraction of the poor solvent H2O, which can induce 1 self-assembly to excimer state and could be applied in information transfer. Moreover, upon visible light irradiation, photoswitchable performance of nanovesicles of 1 was observed in which the emission markedly changes from yellow to blue; this is attributed to the cycloaddition reaction of alkynyl groups and singlet oxygen, which can be generated without the addition of external photosensitizers. The multi-responsive and fluorescence behavior of the alkynylpyrene derivative show that the self-assembly can be used to expand the development of this type of fluorophores, and the novel photoinduced tunability of the fluorescence emission provides an effective strategy to obtain high-performance transmitting and sensing materials.

N/P-Dual-Doped Carbon-Coated Na3V2(PO4)2O2F Microspheres as a High-Performance Cathode Material for Sodium-Ion Batteries.

Na3V2(PO4)2O2F (NVPOF) is attracting great interest due to its large capacity and high working voltage. However, poor electronic conductivity limits the electrochemical performance of NVPOF. Herein, we fabricate N/P-dual-doped carbon-coated NVPOF microspheres (labeled as NVPOF@P/N/C) via a hydrothermal process followed by heat treatment. This microsphere-structured NVPOF@P/N/C composite has a relatively high tap density of 1.22 g/cm3. TEM and XPS results reveal that the dual-doped carbon layer is tightly coated on the NVPOF surface due to the bridging effect of P and has a good protective effect on NVPOF. Density functional theory (DFT) calculations confirm that a N/P-dual-doped carbon layer is advantageous to achieve higher electronic conductivity and lower migration activation energy than those of the undoped and single N- or P-doped carbon layer. As a cathode material for a sodium-ion battery (SIB), NVPOF@P/N/C exhibits high capacity (128 mAh/g at 0.5 C and 122 mAh/g at 2 C) and ultralong cycle performance (only 0.037% capacity fading rate per cycle in 500 cycles at 2 C). We believe that the NVPOF@P/N/C composite is appealing for high-performance SIBs with large energy density.

[Effect of calcium on ion contents and expression of photosynthetic related genes in honeysuckle under salt stress].

Exogenous calcium can enhance the resistance of certain plants to abiotic stress. Research have demonstrated that exogenous calcium could enhances the resistance of honeysuckle under salt stress by promoting the transmission of photosynthetic electrons.The aim of this study was to investigate the effects of exogenous calcium on the contents of Na~+,K~+,Ca~(2+),Mg~(2+)and the expression of photosynthetic related genes Cab and rbc L. In this study,we used ICP-OES to analysis ion contents and used qRT-PCR to analysis the expression patterns of Cab and rbc L. The results showed that CaCl_2 significantly enhanced the K~+-Na~+,Ca~(2+)-Na~+,Mg~(2+)-Na+ratio of honeysuckle treated with 50 and 100 mmol·L~(-1) NaCl. Meanwhile,Cab and rbc L were significantly up-regulated under short-term salt stress,and CaCl_2 promoted this trend. From the two gene expression patterns,rbc L rapidly up-regulated on the first day of stress and then decreased,and was more sensitive to environmental changes. In summary,exogenous calcium could alleviate salt stress and increase plant development by increasing intracellular K~+-Na~+,Ca~(2+)-Na~+,Mg~(2+)-Na+ratio,and the transient overexpression of Cab and rbc L.

[Vinegar processing attenuates toxicity on IEC-6 cells caused by chloroform extraction of Daphne genkwa].

To screen the toxic polar fractions of Daphne genkwa, compare the toxicity of D. genkwa on crypts epithelial cells IEC-6 before and after vinegar processing, and preliminarily investigate the mechanism of D. genkwa vinegar processing on toxicity reducing. The proliferation of IEC-6 cells was observed by MTT. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), lactate dehydrogenase (LDH), as well as the enzyme activity of Na⁺-K⁺-ATPase and Ca²âº-Mg²âº-ATPase were determined in IEC-6 cells to evaluate the oxidative damages degree of IEC-6 cells. The apoptosis and cell cycle were analyzed by Flow Cytometry. The results showed that the dichloromethane extraction was the toxic polar fraction of D. genkwa, and after vinegar processing, the toxicity of dichloromethane fraction was significantly reduced (P<0.01). As compared with the blank control group, the dichloromethane fraction of D. genkwa can obviously decrease the levels of SOD, Na⁺-K⁺-ATPase, Ca²âº-Mg²âº-ATPase (P<0.01) and content of GSH, but increase the level of LDH and MDA in cell supernatant (P<0.01). Besides, it obviously increased the early and late apoptotic rate of IEC-6 cells, obviously decreased the proportion of G1stage cells, increased the ratio of S stage cells and M stage cells (P<0.01). After vinegar processing, as compared with D. genkwa groups of various doses, it can significantly increase the levels of SOD, Na⁺-K⁺-ATPase, Ca²âº-Mg²âº-ATPase (P<0.01) and content of GSH, decrease the level of LDH, MDA(P<0.01), significantly decrease the early and late apoptosis rate of IEC-6 cells (P<0.01), increase the proportion of G1stage cells, and decrease the ratio of S stage cells and M stage cells (P<0.01). Vinegar processing can reduce the toxicity of dichloromethane fraction of D. genkwa, and its mechanism may be associated with improving the activity of antioxidant enzymes and permeability in IEC-6 cells, and decreasing the oxidative damage.

[Puerarin induces apoptosis in A549 cells].

OBJECTIVE: To explore the effect of puerarin induced apoptosis in human non-small cell lung canner A549 cells and its possible mechanisms. METHODS: A549 cells were cultivated in vitro. When 80%~90% confluence was reached, they were treated with puerarin in different concentration (60、120、240 µg/ml). The effects on cell apoptpsis were examined by CCK-8 colorimetry. Characteristic morphological changes of apoptosis were observed by AO/EB staining. The apoptosis of A549 cells were detected by flow cytometry analysis. The proteins level of Apelin and APJ were tested by Western blot. RESULTS: CCK-8 test showed that puerarin could inhibit the proliferation of A549 cells in a time and concentration dependent manner. Flow cytometry analysis indicated that puerarin could make A549 cells apoptosis. Compared with the A549 cells group, the protein expression of Apelin/APJ was decreased in puerarin groups. CONCLUSIONS: Puerarin induces apoptosis in A549 cells, and its mechanism may through the regulation of Apelin/APJ expression.

[The expression and significance of CD151 in pituitary adenomas].

OBJECTIVE: To investigate the expression and significance of CD151 in pituitary adenomas. METHODS: Thirty-six pituitary adenomas were collected immediately after surgery together with five normal pituitary tissue. Real time-PCR, Western blot and immunohistochemistry analysis were performed to detect the expression of CD151 mRNA and protein in thirty-six pituitary adenomases and five normal pituitary tissues. RESULTS: The expression of CD151 in all pituitary adenomases was observed to be significantly higher than that in normal pituitary tissues by Western blot, real time PCR, and immunohistochemistry analysis (P < 0.01). The expression levels of protein and mRNA in invasive pituitary adenomas were much higher than those in non-invasive pituitary adenomas (P < 0.01). CONCLUSION: The results suggested that the expression of CD151 was closely correlated with malignant degree of pituitary adenomas, which indicated the expression of CD151 was intimately correlated with occurrence and development of pituitary adenomas. Detecting CD151 might be a vital index to predict prognosis of pituitary adenomas.