Response Surface Optimized Extraction of Flavonoids from Cacumen platycladi and Antioxidant Activities In vitro

[Objectives]To explore the optimal extraction process and the antioxidant activity of flavonoidsof Cacumen platycladi. [Methods]FCPwas obtained from C. platycladi by a new set extraction process of microwave-assisted extraction,freeze thawing,superfine crushingand freeze drying technology and purification. On the basis of single-factor tests,the quadratic regression parasitism model was established by the extraction amount of total flavonoids with microwave power,alcohol concentration,and liquid-to-solid ratio through the response surface methodology. [Results] The optimal extraction conditions were microwave power of 757 W,alcohol concentration of 69%,liquid-to-solid ratio of21∶ 1,with the optimal extraction yield of 15. 302 9 mg/g. Under the real conditions( microwave power of 800 W,alcohol concentration of69%,liquid-to-solid ratio of 21∶ 1) in our laboratory,the maximum yield of total flavonoids was 15. 9 mg/g,the results fitwell with the prediction of quadratic regression parasitism model. The good antioxidant activity has been determined byscavenging effect of FCP on 1,1-diphenyl-2-picrylhydrazyl( DPPH) radical and superoxide anion free radical with the scavenging yield of 70. 2% and 68. 8% respectively. [Conclusions]All results established a good foundation for furtherdevelopment of C. platycladi products.

A review of existing and emerging binders for silicon anodic Li-ion batteries

Silicon anodes have been extensively studied as a potential alternative to graphite ones for Li-ion batteries.However,their commercial application is limited by the issues of the poor structural and interfacial stability.In this regard,one of the key strategies for fully exploiting the capacity potential of Si-based anodes is to design robust conductive binder networks.Although the amount of binder in the electrode is small,it is,however,considered as a critical component of Si-based anodes for Li-ion batteries.In this review,a brief summary is given from the structural and functional aspects of the existing binders for Si anodes.In particular,three-dimensional and multifunctional polymeric binders with excellent electrical conductivity,flexibility,adhesion prepared by chemical bonding,electrostatic and coordination interactions have become the focus of research,are expected to accelerate the practical application of silicon anodes.Lastly,some suggestions for the future development of Si anodic binders are put forward.

SiOx/C-Ag nanosheets derived from Zintl phase CaSi_(2) via a facile redox reaction for high performance lithium storage

As one of the high-capacity anodes in lithium-ion batteries(LIBs),silicon oxide(SiOx)has attracted wide attention due to its high theoretical capacity,low cost,and proper working voltage.However,the huge volume change and the intrinsic poor conductivity of SiOx still hinder the practical applications.How to address the issues is the focus of current research.In this work,firstly,hydrogen passivated Si nanosheets(Si6H6)were prepared from Zintl phase CaSi2,then,two-dimensional Ag nanoparticle modified SiOVC nanocomposite was prepared via a facile complex redox reaction between SieH6 and AgN03-aniline complexing agent.In this design,aniline was served as carbon sources,and Si6H6could be transformed to SiOx by AgN03 in mild solution condition.The obtained Ag modified SiOVC(SiOx/C-Ag)electrode exhibited high specific capacity(550 mAh·g^(-1)at 0.6 A·g^(-1)),superior rate,and cycling performance when served as anode for LIBs.

Rapid CO_(2) exfoliation of Zintl phase CaSi_(2)-derived ultrathin free-standing Si/SiO_(x)/C nanosheets for high-performance lithium storage

Semiconducting silicon(Si)nanomaterials have great potential for the applications in electronics,physics,and energy storage fields.However,to date,it is still a challenge to realize the batch production of Si nanomaterials via efficient and low-cost approaches,owing to some long-standing shortcomings,e.g.,complex procedures and time and/or energy consumption.Herein,we report a green and inexpensive method to rapidly obtain two-dimensional(2D)free-standing Si/SiO_(x) nanosheets via the rapid thermal exfoliation of layered Zintl compound CaSi_(2).With the help of the rapid exfoliation reaction of CaSi_(2) in the atmosphere of greenhouse gas CO_(2),and the following mild sonication,2D free-standing Si/SiO_(x) nanosheets can be produced with very high yield.After applying the coating of a thin carbon outer layer,the electrodes of Si/SiO_(x)/C nanosheets serving as the anodes for lithium-ion batteries exhibit ultrahigh reversible capacity and outstanding electrochemical stability.We expect this study will provide new insights and inspirations for the convenient and batch production of nanostructural Si-based anode materials towards high-performance lithium-ion batteries.

Rapid construction of highly-dispersed cobalt nanoclusters embedded in hollow cubic carbon walls as an effective polysulfide promoter in high-energy lithium-sulfur batteries

The ultrahigh specific energy density and low cost of lithium-sulfur batteries are suitable for the next generation of energy storage.However,the shuttle issue and sluggish conversion kinetics of polysulfides remain unsolved.Confining metal nanoclusters with strong polarity in conductive porous carbon is an effective strategy for tackling such knotty issues.Herein,we design and synthesize hollow cubic carbon embedded with highly dispersed cobalt nanoclusters as an effective sulfur reservoir for lithium sulfur batteries.The large cavity structure and well-dispersed cobalt nanoclusters,with uniform sizes near 11 nm,enable the hosting structure to hold the high sulfur loading,70%capacity retention after 500 cycles at 2 C with a high sulfur loading of 6.5 mg·cm^(−2),effective stress release,accelerated polysulfide conversion,superior rate performance,strong physical confinement and chemical absorption capability.Further density functional theoretical calculations demonstrate that the welldispersed cobalt nanoclusters in the hosting structure play a critical electrocatalytic role in boosting the capability of absorbing and converting polysulfides.

Targeted combination therapy for glioblastoma by co-delivery of doxorubicin,YAP-siRNA and gold nanorods

The combination of brain targeting drug delivery systems and multi-modal intervention pose a promising therapeutic approach for glioblastoma therapy.In this study,we developed an angiopep-2 peptide modified cationic liposome loaded with doxorubicin,YAP-siRNA and gold nanorods(D/R@Ang2-Lip+Au)simultaneously,which has high encapsulating efficiency for doxorubicin(95.4%)and effective binding of siRNA at N/P ratio of 20:1.The fluorescence imaging and flow cytometry analysis revealed high cellular uptake of D/R@Ang2-Lip+Au.Real-time quantitative polymerase chain reaction and western blot analysis indicated that D/R@Ang2-Lip+Au could effectively inhibit the expression of YAP protein.In vitro and in vivo studies showed that D/R@Ang2-Lip+Au had the ability to target glioblastoma cells,and achieved better anti-proliferative effects compared with non-targeted D/R@Lip+Au.Moreover,in vivo experiment demonstrated that D/R@Ang2-Lip+Au was able to cross the blood-brain barrier,and combination therapy could significantly inhibit tumor growth.Therefore,the multifunctional D/R@Ang2-Lip+Au might provide a novel approach for effectively delivery of DOX,YAP-siRNA and AuNRs into the glioblastoma cells simultaneously and exerting synergistic therapeutic effects.

Bi-functional selection markers assist segregation of transgene-free,genome-edited mutants

Dear Editor,In recent years,CRISPR/Cas9-mediated genome editing has been successfully applied in various plants for functional analysis or crop improvement(Chen et al.,2019).We previously reported DNA-free genome-editing methods to generate transgene-free mutants(Liang et al.,2017;Zhang et al.,2016).