High photoelectric conversion efficiency and fast relaxation time of FA_(0.4)MA_(0.6)PbI_(3) applied in ultrafast modulation of terahertz waves

Active control of terahertz(THz)waves is attracting tremendous attentions in terahertz communications and active photonic devices.Perovskite,due to its excellent photoelectric conversion performance and simple manufacturing process,has emerged as a promising candidate for optoelectronic applications.However,the exploration of perovskites in optically controlled THz modulators is still limited.In this work,the photoelectric properties and carrier dynamics of FA_(0.4)MA_(0.6)PbI_(3)perovskite films were investigated by optical pumped terahertz probe(OPTP)system.The ultrafast carrier dynamics reveal that FA_(0.4)MA_(0.6)PbI_(3)thin film exhibits rapid switching and relaxation time within picosecond level,suggesting that FA_(0.4)MA_(0.6)PbI_(3)is an ideal candidate for active THz devices with ultrafast response.Furthermore,as a proof of concept,a FA_(0.4)MA_(0.6)PbI_(3)-based metadevice with integrating plasma-induced transparency(PIT)effect was fabricated to achieve ultrafast modulation of THz wave.The experimental results demonstrated that the switching time of FA_(0.4)MA_(0.6)PbI_(3)-based THz modulator is near to 3.5 ps,and the threshold of optical pump is as low as 12.7μJ cm^(-2).The simulation results attribute the mechanism of ultrafast THz modulation to photo-induced free carriers in the FA_(0.4)MA_(0.6)PbI_(3)layer,which progressively shorten the capacitive gap of PIT resonator.This study not only illuminates the potential of FA_(0.4)MA_(0.6)PbI_(3)in THz modulation,but also contributes to the field of ultrafast photonic devices.

Genome-wide identification of the CONSTANS-LIKE(COL)family and mechanism of fruit senescence regulation by PpCOL8 in sand pear(Pyrus pyrifolia)

Pyrus pyrifolia Nakai‘Whangkeumbae'is a sand pear fruit with excellent nutritional quality and taste.However,the industrial development of pear fruit is significantly limited by its short shelf life.Salicylic acid(SA),a well-known phytohormone,can delay fruit senescence and improve shelf life.However,the mechanism by which SA regulates CONSTANS-LIKE genes(COLs)during fruit senescence and the role of COL genes in mediating fruit senescence in sand pear are poorly understood.In this study,22 COL genes were identified in sand pear,including four COLs(Pp COL8,Pp COL9a,Pp COL9b,and Pp COL14)identified via transcriptome analysis and 18 COLs through genome-wide analysis.These COL genes were divided into three subgroups according to the structural domains of the COL protein.Pp COL8,with two B-box motifs and one CCT domain,belonged to the first subgroup.In contrast,the other three Pp COLs,Pp COL9a,Pp COL9b,and Pp COL14,with similar conserved protein domains and gene structures,were assigned to the third subgroup.The four COLs showed different expression patterns in pear tissues and were preferentially expressed at the early stage of fruit development.Moreover,the expression of Pp COL8 was inhibited by exogenous SA treatment,while SA up-regulated the expression of Pp COL9a and Pp COL9b.Interestingly,Pp COL8 interacts with Pp MADS,a MADS-box protein preferentially expressed in fruit,and SA up-regulated its expression.While the production of ethylene and the content of malondialdehyde(MDA)were increased in Pp COL8-overexpression sand pear fruit,the antioxidant enzyme(POD and SOD)activity and the expression of Pp POD1 and Pp SOD1 in the sand pear fruits were down-regulated,which showed that Pp COL8 promoted sand pear fruit senescence.In contrast,the corresponding changes were the opposite in Pp MADS-overexpression sand pear fruits,suggesting that Pp MADS delayed sand pear fruit senescence.The co-transformation of Pp COL8 and Pp MADS also delayed sand pear fruit senescence.The results of this study revealed that Pp COL8 can play a key role in pear fruit senescence by interacting with Pp MADS through the SA signaling pathway.

Present Situation of Rural Regional Development and Agricultural Extension Policy

The formulation of agricultural extension policy and the development of rural regional economy present the relationship of mutual existence,mutual influence and mutual promotion.Therefore,it is necessary to study the agricultural extension policy according to the current situation of rural regional development.Agricultural technology extension system is an organization set up at county and township levels to provide farmers with scientific research achievements and practical technical services on planting,animal husbandry,fishery,forestry,agricultural machinery and water conservancy,and it is an important carrier for implementing the strategy of developing agriculture through science and technology.On the basis of expounding the value and significance of rural regional economic development,this paper analyzes the problems existing in China s rural regional development from the aspects of rural infrastructure and public services,rural labor force s cultural and scientific level,rural grass-roots extension system,etc.,and puts forward corresponding measures against the problems.This study has certain theoretical reference value for promoting the all-round development of China s rural economy and realizing the great strategy of rural revitalization in China.

The graphene nanopowder for electro-catalytic oxidation of dopamine and uric acid in the presence of ascorbic acid

The graphene nanopowder for electro-catalytic oxidation of dopamine and uric acid in the presence of ascorbic acid has been investigated by cyclic voltammetry,linear polarization and chronoamperometry.The graphene nanopowder modified electrode was prepared using the drop coating method,which displayed excellent electrocatalytic activity towards the oxidation of dopamine and uric acid compared with the bare glassy carbon electrode in phosphate buffer solution at pH=7.0.Linear responses for dopamine and uric acid were obtained in the ranges of3.3μmol/L to 249.1μmol/L and 6.7μmol/L to 386.3μmol/L with detection limits of 1.5μmol/L and 2.7μmol/L(S/N=3),respectively.The response time was less than 2 s in case of dopamine and 3 s in case of uric acid,respectively.The results demonstrated that the graphene nanopowder had potential for detecting dopamine and uric acid.

自体皮质骨联合含重组人骨形态发生蛋白2磷酸钙骨粉修复牙槽突裂的探索性研究

目的:总结采用下颌单层皮质骨联合负载重组人骨形态发生蛋白2的自固化磷酸钙骨粉移植修复牙槽突裂的成骨效果。方法:回顾2020年12月至2021年11月间上海第九人民医院口腔颅颌面科采用上述方法治疗的牙槽突裂病例,分析成骨效果及并发症发生情况。结果:共纳入病例8例,平均骨吸收率28.88%,1例发生伤口裂开,经过治疗仍疗效良好;1例术后2周伤口裂开伴感染,术后6月拍摄电子计算机断层扫描发现移植骨与周围骨不连续,术后8月时皮质骨从裂开处排出,其余6例随访期间无明显并发症。结论:下颌单层皮质骨联合负载重组人骨形态发生蛋白2的自固化磷酸钙骨粉移植修复牙槽突裂效果良好,骨吸收率低,新生骨密度高,创伤小,具有临床推广价值。

Peptide therapeutics and assemblies for cancer immunotherapy

Immunotherapy has been considered as one of the most promising strategies for protection against cancer cells due to the tremendous advantages arising from host immune defense.However,establishing versatile strategies with high biosafety and the capability for efficient modulation of immune responses remains challenging.The structural features resembling native proteins of peptides bestow their great potential to address these challenges via either directly eliciting immune responses or improving the efficacy of therapeutics.This review summarizes the progress of cancer immunotherapy achieved based on the strategies utilizing short peptides as therapeutic agents or peptide assemblies as delivery scaffolds,beyond long sequences like proteins and polypeptides.Starting from a brief introduction of cancer immunotherapy,we outline the peptide sequences in terms of their specific functions including immune checkpoint blockades,vaccine antigens and adjuvants.We particularly highlight peptide-based nanomaterials as scaffolds for targeting delivery or co-delivery of multiple therapeutics to enhance immunogenicity.The extraordinary therapeutic efficacy of the limited examples covered here demonstrates the great potency of the peptide-based strategies in modulating immune responses,thus potentially facilitating the clinical translation of cancer immunotherapy in the future.