The photonic crystal structure has attracted much attention due to its ability to confine light.In this paper,we present our study on an improved Smith-Purcell radiation from a simple metal photonic crystal excited by...The photonic crystal structure has attracted much attention due to its ability to confine light.In this paper,we present our study on an improved Smith-Purcell radiation from a simple metal photonic crystal excited by moving electrons.Different from the wide-band Smith-Purcell radiation from a single metal grating,the results show that the injected electrons could induce more dipole oscillations inside the multi-grating structure,and it leads to the enhancement of the radiation intensity.In addition,there are strong resonances in metal multi-grating structure,and the resonance characteristics may narrow the radiation band,which leads to a radiation with an obvious peak in the spectrum.Therefore,the multi-grating structure has the ability to enhance the radiation intensity and shape the radiation frequency band.By optimizing the structure parameters,coherent and tunable Smith-Purcell radiation can be realized,and it provides a potential way to develop band-controllable light or THz radiation source.展开更多
Background Aims:To summarize the epidemiologic evidence on the association between single nucleotide polymorphisms(SNPs)of folate metabolism genes from parents and children and risk of congenital heart diseases(CHDs)b...Background Aims:To summarize the epidemiologic evidence on the association between single nucleotide polymorphisms(SNPs)of folate metabolism genes from parents and children and risk of congenital heart diseases(CHDs)by a comprehensive systematic review and meta-analysis.Methods and results:Pub Med,Embase,Google Scholar,Cochrane Libraries,and Chinese databases were searched to identify potential studies through July2021 For mothers,the polymorphisms of Methylenetetrahydrofolate Reductase(MTHFR)at rs1801133 and rs1801131 were significantly associated with risk of CHDs in the homozygote comparisons(T/T vs C/C at rs1801133:OR:1.50,95%CI:1.31-1.71;C/C vs A/A at rs1801131:OR:1.39,95%CI:1.04-1.86).For fathers,the polymorphisms of MTHFR at rs1801133 were significantly associated with risk of CHDs in the heterozygote comparisons(C/T vs C/C:OR:1.26,95%CI:1.04-1.53).For children,the polymorphisms of MTHFR at rs1801133(T/T vs C/C:OR:2.05,95%CI:1.57-2.66),rs1801131(A/C vs A/A:OR:1.32,95%CI:1.06-1.63),and rs2274976(G/A vs G/G:OR:0.75,95%CI:0.61-0.92),and methionine synthase reductase(MSR)at rs1801394(G/G vs A/A:OR:1.85,95%CI:1.21-2.85)and rs1532268(T/T vs C/C:OR:2.44,95%CI:1.15-5.21;C/T vs C/C:OR:1.53,95%CI:1.11-2.10).This review also assessed the risk of specific CHD subtypes associated with folate metabolism gene SNPs of children.Relevant heterogeneity moderators have been identified by subgroup analysis.Sensitivity analysis yielded consistent results.No evidence of publication bias was observed.Conclusions:The present study indicates that polymorphisms of maternal MTHFR at rs1801133 and rs1801131,parental MTHFR at rs1801133,as well as children’s MTHFR at rs1801133,rs1801131 and rs2274976,and MSR at rs1801394 and rs1532268 are significantly associated with risk of CHDs.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61921002,62171098,and 92163204)。
文摘The photonic crystal structure has attracted much attention due to its ability to confine light.In this paper,we present our study on an improved Smith-Purcell radiation from a simple metal photonic crystal excited by moving electrons.Different from the wide-band Smith-Purcell radiation from a single metal grating,the results show that the injected electrons could induce more dipole oscillations inside the multi-grating structure,and it leads to the enhancement of the radiation intensity.In addition,there are strong resonances in metal multi-grating structure,and the resonance characteristics may narrow the radiation band,which leads to a radiation with an obvious peak in the spectrum.Therefore,the multi-grating structure has the ability to enhance the radiation intensity and shape the radiation frequency band.By optimizing the structure parameters,coherent and tunable Smith-Purcell radiation can be realized,and it provides a potential way to develop band-controllable light or THz radiation source.
基金supported by the Project Funded by National Key Research and Development Project(No.2018YFE0114500)National Natural Science Foundation Program of China(No.82073653 and 81803313)+5 种基金China Postdoctoral Science Foundation(No.2020M682644)Hunan Provincial Science and Technology Talent Support Project(No.2020TJ-N07)Hunan Provincial Key Research and Development Program(No.2018SK2063,No.2018SK2064)Natural Science Foundation of Hunan Province(No.2018JJ2551)Open Project from NHC Key Laboratory of Birth Defect for Research and Prevention(No.KF2020006)Science and Technology Planning Project of Guangdong Province(No.2020A1414010152)。
文摘Background Aims:To summarize the epidemiologic evidence on the association between single nucleotide polymorphisms(SNPs)of folate metabolism genes from parents and children and risk of congenital heart diseases(CHDs)by a comprehensive systematic review and meta-analysis.Methods and results:Pub Med,Embase,Google Scholar,Cochrane Libraries,and Chinese databases were searched to identify potential studies through July2021 For mothers,the polymorphisms of Methylenetetrahydrofolate Reductase(MTHFR)at rs1801133 and rs1801131 were significantly associated with risk of CHDs in the homozygote comparisons(T/T vs C/C at rs1801133:OR:1.50,95%CI:1.31-1.71;C/C vs A/A at rs1801131:OR:1.39,95%CI:1.04-1.86).For fathers,the polymorphisms of MTHFR at rs1801133 were significantly associated with risk of CHDs in the heterozygote comparisons(C/T vs C/C:OR:1.26,95%CI:1.04-1.53).For children,the polymorphisms of MTHFR at rs1801133(T/T vs C/C:OR:2.05,95%CI:1.57-2.66),rs1801131(A/C vs A/A:OR:1.32,95%CI:1.06-1.63),and rs2274976(G/A vs G/G:OR:0.75,95%CI:0.61-0.92),and methionine synthase reductase(MSR)at rs1801394(G/G vs A/A:OR:1.85,95%CI:1.21-2.85)and rs1532268(T/T vs C/C:OR:2.44,95%CI:1.15-5.21;C/T vs C/C:OR:1.53,95%CI:1.11-2.10).This review also assessed the risk of specific CHD subtypes associated with folate metabolism gene SNPs of children.Relevant heterogeneity moderators have been identified by subgroup analysis.Sensitivity analysis yielded consistent results.No evidence of publication bias was observed.Conclusions:The present study indicates that polymorphisms of maternal MTHFR at rs1801133 and rs1801131,parental MTHFR at rs1801133,as well as children’s MTHFR at rs1801133,rs1801131 and rs2274976,and MSR at rs1801394 and rs1532268 are significantly associated with risk of CHDs.
