A scalable approach to obtaining high-density, large-area single-walled carbon nanotube （SWNT） arrays is essential for realizing the full potential of SWNTs in practical electronic devices; this is still a great cha...A scalable approach to obtaining high-density, large-area single-walled carbon nanotube （SWNT） arrays is essential for realizing the full potential of SWNTs in practical electronic devices; this is still a great challenge. Here, we report an improved synthetic method for large-area growth of ultra-high-density SWNT arrays on sapphire surfaces by combining Trojan catalysts （released from the substrate, to assure ultra-high density） with Mo nanoparticles （loaded on the surface, to stabilize the released Trojan catalysts） as cooperating catalysts. Dense and perfectly aligned SWNTs covered the entire substrate and the local density was as high as 160 tubes/pro. Field-effect transistors （FETs） built on such arrays gave an output current density of -488 μA/μm at the drain-source voltage （Vds） = the gate-source voltage （Vgs） = -2 V, corresponding to an on-conductance per width of 244 μS/μm. These results confirm the wide range of potential applications of Trojan-Mo catalysts in the structure-controlled growth of SWNTs.展开更多
Meiosis produces the haploid gametes required by all sexually reproducing organisms,occurring in specific temperature ranges in different organisms.However,how meiotic thermotolerance is regulated remains largely unkn...Meiosis produces the haploid gametes required by all sexually reproducing organisms,occurring in specific temperature ranges in different organisms.However,how meiotic thermotolerance is regulated remains largely unknown.Using the model organism Caenorhabditis elegans,here,we identified the synaptonemal complex(SC)protein SYP-5 as a critical regulator of meiotic thermotolerance.syp-5-null mutants maintained a high percentage of viable progeny at 20℃ but produced significantly fewer viable progeny at 25℃,a permissive temperature in wild-type worms.Cytological analysis of meiotic events in the mutants revealed that while SC assembly and disassembly,as well as DNA double-strand break repair kinetics,were not affected by the elevated temperature,crossover designation,and bivalent formation were significantly affected.More severe homolog segregation errors were also observed at elevated temperature.A temperature switching assay revealed that late meiotic prophase events were not temperature-sensitive and that meiotic defects during pachytene stage were responsible for the reduced viability of syp-5 mutants at the elevated temperature.Moreover,SC polycomplex formation and hexanediol sensitivity analysis suggested that SYP-5 was required for the normal properties of the SC,and charge-interacting elements in SC components were involved in regulating meiotic thermotolerance.Together,these findings provide a novel molecular mechanism for meiotic thermotolerance regulation.展开更多
Carbon nanotubes(CNTs) have received broad attention in the past decades due to their excellent physical and chemical properties and thus been regarded as a powerful candidate for future star-materials. Although vario...Carbon nanotubes(CNTs) have received broad attention in the past decades due to their excellent physical and chemical properties and thus been regarded as a powerful candidate for future star-materials. Although various CNT products and their related applications have been demonstrated recently, their performance can hardly meet the researchers’ expectations compared with their theoretical properties. The current predicament is caused by the immature synthesis method, including the basic science and the producing technology. As the synthesis with controlled structures determines its future, this review summarizes the progress on the basic research and industrialization of CNTs in the past decades, including the fine structure control, aggregation status design and scale-up production, and further points out the way for the future development of CNTs combining with specific applications.展开更多
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Nos. 21233001, 21129001, 51272006, 51432002, and 51121091）, the National Basic Research Program of China （No. 2011CB932601） and Beijing Municipal Science and Technology Commission （No. D141100000614001）.
文摘A scalable approach to obtaining high-density, large-area single-walled carbon nanotube （SWNT） arrays is essential for realizing the full potential of SWNTs in practical electronic devices; this is still a great challenge. Here, we report an improved synthetic method for large-area growth of ultra-high-density SWNT arrays on sapphire surfaces by combining Trojan catalysts （released from the substrate, to assure ultra-high density） with Mo nanoparticles （loaded on the surface, to stabilize the released Trojan catalysts） as cooperating catalysts. Dense and perfectly aligned SWNTs covered the entire substrate and the local density was as high as 160 tubes/pro. Field-effect transistors （FETs） built on such arrays gave an output current density of -488 μA/μm at the drain-source voltage （Vds） = the gate-source voltage （Vgs） = -2 V, corresponding to an on-conductance per width of 244 μS/μm. These results confirm the wide range of potential applications of Trojan-Mo catalysts in the structure-controlled growth of SWNTs.
基金supported by grants from the National Natural Science Foundation of China(31871360,32022018,and 31701176 to J.G.and 31900557 to R.W.)Natural Science Foundation of Shandong Province(ZR2019PC050 to H.N.).
文摘Meiosis produces the haploid gametes required by all sexually reproducing organisms,occurring in specific temperature ranges in different organisms.However,how meiotic thermotolerance is regulated remains largely unknown.Using the model organism Caenorhabditis elegans,here,we identified the synaptonemal complex(SC)protein SYP-5 as a critical regulator of meiotic thermotolerance.syp-5-null mutants maintained a high percentage of viable progeny at 20℃ but produced significantly fewer viable progeny at 25℃,a permissive temperature in wild-type worms.Cytological analysis of meiotic events in the mutants revealed that while SC assembly and disassembly,as well as DNA double-strand break repair kinetics,were not affected by the elevated temperature,crossover designation,and bivalent formation were significantly affected.More severe homolog segregation errors were also observed at elevated temperature.A temperature switching assay revealed that late meiotic prophase events were not temperature-sensitive and that meiotic defects during pachytene stage were responsible for the reduced viability of syp-5 mutants at the elevated temperature.Moreover,SC polycomplex formation and hexanediol sensitivity analysis suggested that SYP-5 was required for the normal properties of the SC,and charge-interacting elements in SC components were involved in regulating meiotic thermotolerance.Together,these findings provide a novel molecular mechanism for meiotic thermotolerance regulation.
基金supported by the Ministry of Science and Technology of China (2016YFA0200101 and 2016YFA0200104)the National Natural Science Foundation of China (51432002, 21790052 and 51720105003)+2 种基金Beijing Municipal Science and Technology Planning Project (Z161100002116026)China PostdoctoralScience Foundation (8201400852 and 8201400892)the National Program for Thousand Young Talents of China
文摘Carbon nanotubes(CNTs) have received broad attention in the past decades due to their excellent physical and chemical properties and thus been regarded as a powerful candidate for future star-materials. Although various CNT products and their related applications have been demonstrated recently, their performance can hardly meet the researchers’ expectations compared with their theoretical properties. The current predicament is caused by the immature synthesis method, including the basic science and the producing technology. As the synthesis with controlled structures determines its future, this review summarizes the progress on the basic research and industrialization of CNTs in the past decades, including the fine structure control, aggregation status design and scale-up production, and further points out the way for the future development of CNTs combining with specific applications.
