The oral cavity of each person is home to hundreds of bacterial species.While taxa for oral diseases have been studied using culture-based characterization as well as amplicon sequencing,metagenomic and genomic inform...The oral cavity of each person is home to hundreds of bacterial species.While taxa for oral diseases have been studied using culture-based characterization as well as amplicon sequencing,metagenomic and genomic information remains scarce compared to the fecal microbiome.Here,using metagenomic shotgun data for 3346 oral metagenomic samples together with 808 published samples,we obtain 56,213 metagenome-assembled genomes(MAGs),and more than 64%of the 3589 species-level genome bins(SGBs)contain no publicly available genomes.The resulting genome collection is representative of samples around the world and contains many genomes from candidate phyla radiation(CPR)that lack monoculture.Also,it enables the discovery of new taxa such as a genus Candidatus Bgiplasma within the family Acholeplasmataceae.Large-scale metagenomic data from massive samples also allow the assembly of strains from important oral taxa such as Porphyromonas and Neisseria.The oral microbes encode genes that could potentially metabolize drugs.Apart from these findings,a strongly male-enriched Campylobacter species was identified.Oral samples would be more user-friendly collected than fecal samples and have the potential for disease diagnosis.Thus,these data lay down a genomic framework for future inquiries of the human oral microbiome.展开更多
2,2’,7,7’-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9’-spirobifluorene(spiro-OMeTAD), as the most commonly used hole transport material(HTM), plays a significant role in the normal structured(n-i-p) high-efficiency ...2,2’,7,7’-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9’-spirobifluorene(spiro-OMeTAD), as the most commonly used hole transport material(HTM), plays a significant role in the normal structured(n-i-p) high-efficiency perovskite solar cells(PSCs). In general, it is prepared by a halogen solvent(chlorobenzene, CBZ) and needs an ion dopant(lithium bis(trifluoromethanesulfonyl)imide, Li-TFSI) to improve its conductivity and hole mobility. However, such a halogen solvent is not environmentally friendly and the widely used LiTFSI dopant would affect the stability of PSCs. Herein, we develop a non-halogen solvent-tetrahydrofuran(THF)-prepared spiro-OMeTAD solution with a new p-type dopant,potassium bis(fluorosulfonyl)imide(K-FSI), to apply into PSCs. By this strategy, high-hole-mobility spiro-OMeTAD film is achieved. Meanwhile, the potassium ions introduced by diffusion into perovskite surface passivate the interfacial defects. Therefore, a hysteresis-free champion PSC with an efficiency of 21.02% is obtained, along with significantly improved stability against illumination and ambient conditions. This work provides a new strategy for HTMs toward hysteresis-free high-efficiency and stable PSCs by substituting dopants.展开更多
Line-of-sight(LoS)probability prediction is critical to the performance optimization of wireless communication systems.However,it is challenging to predict the LoS probability of air-to-ground(A2G)communication scenar...Line-of-sight(LoS)probability prediction is critical to the performance optimization of wireless communication systems.However,it is challenging to predict the LoS probability of air-to-ground(A2G)communication scenarios,because the altitude of unmanned aerial vehicles(UAVs)or other aircraft varies from dozens of meters to several kilometers.This paper presents an altitude-dependent empirical LoS probability model for A2G scenarios.Before estimating the model parameters,we design a K-nearest neighbor(KNN)based strategy to classify LoS and non-LoS(NLoS)paths.Then,a two-layer back propagation neural network(BPNN)based parameter estimation method is developed to build the relationship between every model parameter and the UAV altitude.Simulation results show that the results obtained using our proposed model has good consistency with the ray tracing(RT)data,the measurement data,and the results obtained using the standard models.Our model can also provide wider applicable altitudes than other LoS probability models,and thus can be applied to different altitudes under various A2G scenarios.展开更多
基金supported by the National Key Program for Infectious Diseases of China(Grant No.2018ZX10714-002).
文摘The oral cavity of each person is home to hundreds of bacterial species.While taxa for oral diseases have been studied using culture-based characterization as well as amplicon sequencing,metagenomic and genomic information remains scarce compared to the fecal microbiome.Here,using metagenomic shotgun data for 3346 oral metagenomic samples together with 808 published samples,we obtain 56,213 metagenome-assembled genomes(MAGs),and more than 64%of the 3589 species-level genome bins(SGBs)contain no publicly available genomes.The resulting genome collection is representative of samples around the world and contains many genomes from candidate phyla radiation(CPR)that lack monoculture.Also,it enables the discovery of new taxa such as a genus Candidatus Bgiplasma within the family Acholeplasmataceae.Large-scale metagenomic data from massive samples also allow the assembly of strains from important oral taxa such as Porphyromonas and Neisseria.The oral microbes encode genes that could potentially metabolize drugs.Apart from these findings,a strongly male-enriched Campylobacter species was identified.Oral samples would be more user-friendly collected than fecal samples and have the potential for disease diagnosis.Thus,these data lay down a genomic framework for future inquiries of the human oral microbiome.
基金financially supported by the National Key Research and Development Plan (2019YFE0107200 and 2017YFE0131900)the National Natural Science Foundation of China (21875178 and 91963209)Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (XHD2020-001 and XHT2020-005)。
文摘2,2’,7,7’-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9’-spirobifluorene(spiro-OMeTAD), as the most commonly used hole transport material(HTM), plays a significant role in the normal structured(n-i-p) high-efficiency perovskite solar cells(PSCs). In general, it is prepared by a halogen solvent(chlorobenzene, CBZ) and needs an ion dopant(lithium bis(trifluoromethanesulfonyl)imide, Li-TFSI) to improve its conductivity and hole mobility. However, such a halogen solvent is not environmentally friendly and the widely used LiTFSI dopant would affect the stability of PSCs. Herein, we develop a non-halogen solvent-tetrahydrofuran(THF)-prepared spiro-OMeTAD solution with a new p-type dopant,potassium bis(fluorosulfonyl)imide(K-FSI), to apply into PSCs. By this strategy, high-hole-mobility spiro-OMeTAD film is achieved. Meanwhile, the potassium ions introduced by diffusion into perovskite surface passivate the interfacial defects. Therefore, a hysteresis-free champion PSC with an efficiency of 21.02% is obtained, along with significantly improved stability against illumination and ambient conditions. This work provides a new strategy for HTMs toward hysteresis-free high-efficiency and stable PSCs by substituting dopants.
基金Project supported by the National Key Scientific Instrument and Equipment Development Project,China(No.61827801)the Open Research Fund of the State Key Laboratory of Integrated Services Networks,China(No.ISN22-11)。
文摘Line-of-sight(LoS)probability prediction is critical to the performance optimization of wireless communication systems.However,it is challenging to predict the LoS probability of air-to-ground(A2G)communication scenarios,because the altitude of unmanned aerial vehicles(UAVs)or other aircraft varies from dozens of meters to several kilometers.This paper presents an altitude-dependent empirical LoS probability model for A2G scenarios.Before estimating the model parameters,we design a K-nearest neighbor(KNN)based strategy to classify LoS and non-LoS(NLoS)paths.Then,a two-layer back propagation neural network(BPNN)based parameter estimation method is developed to build the relationship between every model parameter and the UAV altitude.Simulation results show that the results obtained using our proposed model has good consistency with the ray tracing(RT)data,the measurement data,and the results obtained using the standard models.Our model can also provide wider applicable altitudes than other LoS probability models,and thus can be applied to different altitudes under various A2G scenarios.
