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Purification of total flavonoids from Ginkgo biloba flowers (GBF) extracts were studied using six resins. Adsorption-desorption experiments indicated that polyamide resin is the most suitable resin. The optimal purification process of total flavonoids of GBF was as follows: a loading concentration of 5.85 mg/mL, a loading volume of 1 bed volume (BV), a loading flow rate of 2 BV/h, a water volume of 2.67 BV, and a desorption solution of 40% ethanol. Under these conditions, the maximum purity of total flavonoids was 37.1 ± 1.1%. The antioxidant activity of purified flavonoids was further evaluated in vitro. It showed that the 40% ethanol purified fraction (Fr. B) group had the strongest antioxidant activity of the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity concentration for 50% of maximal effect (EC50, 145.4 ± 13.8 µg/mL) and ferric reducing ability (2.5 ± 0.2 mM FeSO4 equivalent mg−1 Fr. B). In addition, at the concentration of 160 µg/mL, the Fr. B strikingly increased the viability rate of hydrogen peroxide stimulated PC-12 cells to normal levels (***p < 0.001). This method provides a basis for the application and development of GBF resources. It indicated that the purified GBF flavonoids can be used as a source of potential antioxidant. [ABSTRACT FROM AUTHOR]

Rational design of promising electrolyte is considered as an effective strategy to improve the cycling stability of lithium metal batteries (LMBs). Here, an elaborately designed ionic liquid‐based electrolyte is proposed that is composed of lithium bis(trifluoromethanesulfonyl)imide as the lithium salt, 1‐ethyl‐3‐methylimidazolium nitrate ionic liquid ([EMIm][NO3] IL) and fluoroethylene carbonate (FEC) as the functional solvents, and 1,2‐dimethoxyethane (DME) as the diluent solvent. Using [EMIm][NO3] IL as the solvent component facilitates a special Li+‐coordinated NO3− solvation structure, which enables the continues electrochemical reduction of solvated NO3− and the formation of remarkably stable and conductive solid electrolyte interface. With FEC as another functional solvent and DME as the diluent solvent, the formulated electrolyte delivers high oxidative stability and ionic conductivity, and endows improved electrochemical reaction kinetics. Therefore, the formulated electrolyte demonstrates exceedingly reversible and stable Li stripping/plating behavior with high average Coulombic efficiency (98.8%) and ultralong cycling stability (3500 h). Notably, the high‐voltage Li|LiNi0.8Co0.1Mn0.1O2 full cell with IL‐based electrolyte exhibits enhanced cyclability with a capacity retention of 65% after 200 cycles under harsh conditions of low negative/positive ratio (3.1) and lean electrolyte (2.5 µL mg−1). This study creates the first NO3−‐based ionic liquid electrolyte and evokes the avenue for practical high‐voltage LMBs. [ABSTRACT FROM AUTHOR]

Glucose oxidase (GOD)‐based starvation therapy (ST), which inhibits the growth and proliferation of cancer cells by consuming glucose, has attracted intensive attention as an emerging non‐invasive method for fighting cancers. However, the enzyme activity of GOD is greatly limited in vivo because of its optimal catalytic activity in the temperature range of 43–60 °C. Herein, a photothermal‐enhanced starvation strategy is developed based on our engineered organosilica hybrid micelles (TiO2‐x@POMs‐GOD), in which the fluoride‐doped TiO2‐x with photothermal properties is encapsulated in the cores of organosilica cross‐linked micelles and GOD is immobilized on the carboxyl groups of PAA segments. With its internalization by cancer cells, the conjugated GOD can effectively deplete glucose to achieve the ST effect, which can be remarkably enhanced by the loaded fluoride‐doped TiO2‐x with NIR laser irradiation, thus cooperatively contributing to the efficient treatment of TiO2‐x@POMs‐GOD on various cancer cells. This suggests great potential for TiO2‐x@POMs‐GOD in photothermal‐enhanced ST in vivo. [ABSTRACT FROM AUTHOR]

Binary Cu2Se and Cu2Te have gained great attention recently because of their interesting and abnormal physical properties, such as ultralow thermal conductivity, high carrier mobility, large effective mass of carriers and excellent thermoelectric performance. In this study, we find that these two compounds are completely miscible throughout the studied composition range. The trigonal structure of Cu2Se is maintained when the Te content x is 0.2, but a new trigonal structure is formed when the Te content x is between 0.3 and 0.7. The carrier concentration is greatly improved when increasing the Te content in Cu2Se1−xTex solid solutions, resulting in a much reduced electrical resistivity and Seebeck coefficient in the whole temperature range as compared with those of binary Cu2Se. The total thermal conductivity is inversely increased due to the contribution from enhanced carrier thermal conductivity. As a result, the overall thermoelectric performance of Cu2Se1−xTex solid solutions lies between Cu2Se and Cu2Te. We also find that the quality factor of Cu2Se1−xTex is higher than those of most typical thermoelectric materials. Thus the thermoelectric performance can be further improved if the intrinsically high hole carrier concentrations can be reduced in Cu2Se1−xTex. [ABSTRACT FROM AUTHOR]

Most of the state-of-the-art thermoelectric (TE) materials exhibit high crystal symmetry, multiple valleys near the Fermi level, heavy constituent elements with small electronegativity differences, or complex crystal structure. Typically, such general features have been well observed in those well-known TE materials such as Bi 2 X 3 -, SnX-, and PbX-based compounds (X = S, Se, and Te). The performance is usually high in the materials with heavy constituent elements such as Te and Se, but it is low for light constituent elements such as S. However, there is a great abnormality in Cu 2 X-based compounds in which Cu 2 Te has much lower TE figure of merit (zT) than Cu 2 S and Cu 2 Se. It is demonstrated that the Cu 2 Te-based compounds are also excellent TE materials if Cu deficiency is sufficiently suppressed. By introducing Ag 2 Te into Cu 2 Te, the carrier concentration is substantially reduced to significantly improve the zT with a record-high value of 1.8, 323% improvement over Cu 2 Te and outperforms any other Cu 2 Te-based materials. The single parabolic band model is used to further prove that all Cu 2 X-based compounds are excellent TE materials. Such finding makes Cu 2 X-based compounds the only type of material composed of three sequent main group elements that all possess very high zT  s above 1.5., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Liquid-like binary Cu 2-δ X (X = S, Se, and Te) chalcogenides and their ternary solid solutions have gained notable attention in thermoelectrics due to their interesting and abnormal thermal and electrical transport properties. However, previous studies mainly focus on a single element alloying at either an anion or cation site whereas the investigation on cation/anion co-alloying is very rare so far. Here, a series of quaternary Cu 2-2 x Ag 2 x Se 1- x S x ( x = 0.01, 0.03, 0.05, 0.1, 0.15) liquid-like copper chalcogenide materials have been fabricated and the effects of Ag/S co-alloying on the thermoelectric properties of Cu 2 Se have been systematically studied. It is found that all compounds are mixed phases at room temperature but single cubic phase at high temperatures. The introduction of Ag and S in Cu 2 Se brings about a large mass fluctuation rather than strain field fluctuation that effectively suppresses the lattice thermal conductivity. Furthermore, on increasing the Ag and S contents, the high electrical conductivity of pristine Cu 2 Se is well tuned to the optimal range derived from the single parabolic band model analysis. Consequently, a peak zT of 1.6 at 900 K is achieved in Cu 1.8 Ag 0.2 Se 0.9 S 0.1 , which is about 33% higher than that of binary Cu 2 Se.