Metal-organic frameworks based single-atom catalysts for advanced fuel cells and rechargeable batteries

The next-generation energy storage systems such as fuel cells,metal-air batteries,and alkali metal(Li,Na)-chalcogen(S,Se)batteries have received increasing attention owing to their high energy density and low cost.However,one of the main obstacles of these systems is the poor reaction kinetics in the involved chemical reactions.Therefore,it is essential to incorporate suitable and efficient catalysts into the cell.These years,single-atom catalysts(SACs)are emerging as a frontier in catalysis due to their maximum atom efficiency and unique reaction selectivity.For SACs fabrication,metal-organic frameworks(MOFs)have been confirmed as promising templates or precursors due to their high metal loadings,structural adjustability,porosity,and tailorable catalytic site.In this review,we summarize effective strategies for fabricating SACs by MOFs with corresponding advanced characterization techniques and illustrate the key role of MOFs-based SACs in these batteries by explaining their reaction mechanisms and challenges.Finally,current applications,prospects,and opportunities for MOFs-based SACs in energy storage systems are discussed.

Evaluation of Heavy Metals and Pesticide Residues in Dendrobium officinale Produced in Guangxi

[Objectives]To establish a method for the determination of heavy metals and pesticide residues in Dendrobium officinale produced in Guangxi and its culture substrate.[Methods]The contents of five heavy metals(Pb,Cd,As,Hg and Cu)were determined by the atomic absorption spectrophotometric(AAS)method;residues of 9 organochlorine pesticides(α-BHC,β-BHC,γ-BHC,δ-BHC,p,p′-DDT,p,p′-DDE,p,p′-DDD,o,p′-DDT and pentachloronitrobenzene)were determined by gas chromatography(GC).[Results]The contents of five heavy metals in the medicinal materials of D.officinale produced in Guangxi were 0.96,0.21,0.021 mg/kg,and not detected,and 0.35 mg/kg.The contents of five heavy metals in the culture substrate were 0.03,0.19,0.21,0.004 and 1.80 mg/kg,respectively;the content of 9 organochlorine pesticide residues in the sample was not detected.[Conclusions]The detection results of heavy metal content and organochlorine pesticide residues in D.officinale produced in Guangxi and its substrate are consistent with the limit requirements of the Chinese Pharmacopoeia.This experiment is expected to provide reliable data reference for ensuring the safety of the drug resources of D.officinale in Guangxi.

Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous System

In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system,through consulting related literatures,this paper summarized the pharmacological effects of the active components of Gastrodiae Rhizoma.The pharmacological effects of the active components of Gastrodiae Rhizoma on the central nervous system include improving the ability of learning and memory,analgesia,sedation and hypnosis,anticonvulsant,anti-aging,anti-anxiety and neuroprotective effects.The active components of Gastrodiae Rhizoma have certain curative effect in the treatment of some diseases of the central nervous system.At present,it has been widely used clinically.There are no toxic and side effects at conventional doses,and it is worth popularizing and applying.

Difference Analysis of Secondary Metabolites of Herba Polygoni Chinensis from Guangxi

[Objectives]The differences in secondary metabolites of Herba Polygoni Chinensis from Guangxi were analyzed,in order to find flavonoids which can antagonize liver injury and provide a basis for the quality evaluation of Herba Polygoni Chinensis.[Methods]UPLC-MS was used to analyze the secondary metabolites of Herba Polygoni Chinensis,and emphasis was placed on flavonoids.[Results]Flavonoids were abundant in the secondary metabolites of Herba Polygoni Chinensis.Quercitrin,catechin gallate,epicatechin gallate,hyperoside and so on were screened as the components with high content and antagonistic effect on liver injury.[Conclusions]Quercitrin was the flavonoid compound with the highest content among the three origins.It is stable and has a good protective effect on liver,which is representative.Quercitrin can be considered as the target component to be used as an important index for quality evaluation of Herba Polygoni Chinensis.

Analysis of the Volatile Components of Polygonum chinense L.Extracted with Different Solvents by GC-MS

[Objectives]This study was conducted to investigate the volatile components of Polygonum chinense L.[Methods]The volatile components of the methanol extract,ethyl acetate extract,chloroform extract and petroleum ether extract of P.chinense were analyzed and determined by gas chromatography.[Results]The volatile components of the methanol extract from P.chinense were the most,and phenolic acids and ketones accounted for a relatively high proportion,among which pyrogallic acid had the highest content.The ethyl acetate extract contained the second most volatile components,mostly acids and esters,of whichβ-sitosterol had the highest content;the chloroform and petroleum ether extracts had relatively few types of volatile components,most of which were alkanes,and the content ofγ-sitosterol shared by the two was the highest.The common substances of the four extracts were palmitic acid and phytol.[Conclusions]This study provides a theoretical basis for the quality evaluation of P.chinense and a scientific basis for its resource development.

Advances in the Treatment of Hepatitis with Flavonoids

Flavonoids are important compounds in natural medicines.They have a wide range of pharmacological activity and have important research value and development prospects.In this article,literature on the treatment of hepatitis with flavonoids is searched,and research reports on the treatment of hepatitis with flavonoids in the past ten years are sorted out,in order to provide a basis for the in-depth research and further development of flavonoids in the treatment of hepatitis.

VAMP726 from maize and Arabidopsis confers pollen resistance to heat and UV radiation by influencing lignin content of sporopollenin

Sporopollenin in the pollen cell wall protects male gametophytes from stresses.Phenylpropanoid derivatives,including guaiacyl(G)lignin units,are known to be structural components of sporopollenin,but the exact composition of sporopollenin remains to be fully resolved.We analyzed the phenylpropanoid derivatives in sporopollenin from maize and Arabidopsis by thioacidolysis coupled with nuclear magnetic resonance(NMR)and gas chromatography–mass spectrometry(GC–MS).The NMR and GC–MS results confirmed the presence of p-hydroxyphenyl(H),G,and syringyl(S)lignin units in sporopollenin from maize and Arabidopsis.Strikingly,H units account for the majority of lignin monomers in sporopollenin from these species.We next performed a genome-wide association study to explore the genetic basis of maize sporopollenin composition and identified a vesicle-associated membrane protein(ZmVAMP726)that is strongly associated with lignin monomer composition of maize sporopollenin.Genetic manipulation of VAMP726 affected not only lignin monomer composition in sporopollenin but also pollen resistance to heat and UV radiation in maize and Arabidopsis,indicating that VAMP726 is functionally conserved in monocot and dicot plants.Our work provides new insight into the lignin monomers that serve as structural components of sporopollenin and characterizes VAMP726,which affects sporopollenin composition and stress resistance in pollen.