Cytosine and adenosine base editors(CBEs and ABEs)are novel genome-editing tools that have been widely utilized in molecular breeding to precisely modify single-nucleotide polymorphisms(SNPs)critical for plant agronom...Cytosine and adenosine base editors(CBEs and ABEs)are novel genome-editing tools that have been widely utilized in molecular breeding to precisely modify single-nucleotide polymorphisms(SNPs)critical for plant agronomic traits and species evolution.However,conventional BE editors are limited to achieve C-to-T and A-to-G substitutions,respectively.To enhance the applicability of base editing technology in watermelon,we developed an efficient CGBE editor(SCGBE2.0)by removing the uracil glycosylase inhibitor(UGI)unit from the commonly used hA3A-CBE and incorporating the uracil-DNA glycosylase(UNG)component.Seven specific guide RNAs(sgRNAs)targeting five watermelon genes were designed to assess the editing efficiency of SCGBE.The results obtained from stably transformed watermelon plants demonstrated that SCGBE2.0 could efficiently induce C-to-G mutations at positions C5–C9 in 43.2%transgenic plants(with a maximum base conversion efficiency of 46.1%)and C-to-A mutation at position C4 in 23.5%transgenic plants(with a maximum base conversion efficiency of 45.9%).These findings highlight the capability of our integrated SCGBE2.0 editor to achieve C-to-G/A mutations in a site-preferred manner,thus providing an efficient base editing tool for precise base modification and site-directed saturated mutagenesis in watermelon.展开更多
As the most promising alternative to traditional indium tin oxide （ITO）, silver nanowire （AgNW） composite transparent electrodes with improved stabilities compared with that of the pristine AgNWs networks have bee...As the most promising alternative to traditional indium tin oxide （ITO）, silver nanowire （AgNW） composite transparent electrodes with improved stabilities compared with that of the pristine AgNWs networks have been demonstrated in various devices. However, a stable AgNW/polymer composite as the bottom electrode for perovskite solar cells has not yet been reported. Here, a long-term stable, smooth AgNW composite with an antioxidant-modified chitosan polymer was developed. The modified polymer can effectively protect pristine AgNWs from side reactions with perovskite, whereas it does not block the carrier drift through the interface of the insulating polymer. The as-prepared AgNW/polymer composite electrode exhibited a root mean square roughness below 10 nm at a scan size of 50 μm × 50 μm, and its original sheet resistance did not change obviously after aging at 85 ℃ for 40 days in air. As a result, the perovskite solar cell employing the composite as the bottom electrode yielded a power conversion efficiency of 7.9%, which corresponds to nearly 75% of that of the reference device with an ITO electrode.展开更多
It was recently found that the anharmonic phonon–phonon scattering in tungsten is extremely weak at high frequencies,leading to a predominance of electron-phonon scattering and consequently anomalous phonon transport...It was recently found that the anharmonic phonon–phonon scattering in tungsten is extremely weak at high frequencies,leading to a predominance of electron-phonon scattering and consequently anomalous phonon transport behaviors.In this work,we calculate the phonon linewidths of W along high-symmetry directions from first principles.We find that the weak phonon–phonon scattering can be traced back to two factors.The first is the triple degeneracy of the phonon branches at the P and H points,a universal property of elemental body-centered-cubic(bcc)structures.The second is a relatively isotropic character of the phonon dispersions.When both are met,phonon–phonon scattering rates must vanish at the P and H points.The weak phonon–phonon scattering feature is also applicable to Mo and Cr.However,in other elemental bcc substances like Na,the isotropy condition is violated due to the unusually soft character of the lower transverse acoustic phonon branch along the Γ-N direction,opening emission channels and leading to much stronger phonon–phonon scattering.We also look into the distributions of electron meanfree paths(MFPs)at room temperature in tungsten,which can help engineer the resistivity of nanostructured W for applications such as interconnects.展开更多
基金supported by the National Youth Talent Program(A279021801)Earmarked Fund for China Agriculture Research System(CARS-25)+4 种基金Key-Area R&D Program of Guangdong Province(2022B0202060001)Key R&D Program of Shaanxi province(2023-YBNY-008)the Natural Science Foundation of Shaanxi Province(2022JM-112)the Fundamental Research Funds for the Central Universities(2452022111)the Science and Technology Innovation Team of Shaanxi(2021TD-32).
文摘Cytosine and adenosine base editors(CBEs and ABEs)are novel genome-editing tools that have been widely utilized in molecular breeding to precisely modify single-nucleotide polymorphisms(SNPs)critical for plant agronomic traits and species evolution.However,conventional BE editors are limited to achieve C-to-T and A-to-G substitutions,respectively.To enhance the applicability of base editing technology in watermelon,we developed an efficient CGBE editor(SCGBE2.0)by removing the uracil glycosylase inhibitor(UGI)unit from the commonly used hA3A-CBE and incorporating the uracil-DNA glycosylase(UNG)component.Seven specific guide RNAs(sgRNAs)targeting five watermelon genes were designed to assess the editing efficiency of SCGBE.The results obtained from stably transformed watermelon plants demonstrated that SCGBE2.0 could efficiently induce C-to-G mutations at positions C5–C9 in 43.2%transgenic plants(with a maximum base conversion efficiency of 46.1%)and C-to-A mutation at position C4 in 23.5%transgenic plants(with a maximum base conversion efficiency of 45.9%).These findings highlight the capability of our integrated SCGBE2.0 editor to achieve C-to-G/A mutations in a site-preferred manner,thus providing an efficient base editing tool for precise base modification and site-directed saturated mutagenesis in watermelon.
基金supported by the National Key Research and Development Program of China(2017YFA0206500)the National Natural Science Foundation of China(No.22073040)。
基金This study was sponsored by 59th China Postdoctoral Science Foundation （No. 2016M590318）, Special Financial Grant from China Postdoctoral Sdence Foundation （No. 2017T100270）, National Natural Science Foundation of China （Nos. 51603043 and 51673042）, and the Program for Professor of Special Appointment （Eastern Scholar） at Shanghai Institutions of Higher Leaming （No. TP2015002）.
文摘As the most promising alternative to traditional indium tin oxide （ITO）, silver nanowire （AgNW） composite transparent electrodes with improved stabilities compared with that of the pristine AgNWs networks have been demonstrated in various devices. However, a stable AgNW/polymer composite as the bottom electrode for perovskite solar cells has not yet been reported. Here, a long-term stable, smooth AgNW composite with an antioxidant-modified chitosan polymer was developed. The modified polymer can effectively protect pristine AgNWs from side reactions with perovskite, whereas it does not block the carrier drift through the interface of the insulating polymer. The as-prepared AgNW/polymer composite electrode exhibited a root mean square roughness below 10 nm at a scan size of 50 μm × 50 μm, and its original sheet resistance did not change obviously after aging at 85 ℃ for 40 days in air. As a result, the perovskite solar cell employing the composite as the bottom electrode yielded a power conversion efficiency of 7.9%, which corresponds to nearly 75% of that of the reference device with an ITO electrode.
基金We acknowledge support from the Natural Science Foundation of China(NSFC)under Grants No.11704258 and No.11574198the Shenzhen Science,Technology and Innovation Commission under Grant No.JCYJ20170412105922384+1 种基金Y.C.also acknowledges the support from the China Postdoctoral Science Foundation under Grant No.2017M622745J.M.also acknowledges support from NSFC under Grant No.11804229.
文摘It was recently found that the anharmonic phonon–phonon scattering in tungsten is extremely weak at high frequencies,leading to a predominance of electron-phonon scattering and consequently anomalous phonon transport behaviors.In this work,we calculate the phonon linewidths of W along high-symmetry directions from first principles.We find that the weak phonon–phonon scattering can be traced back to two factors.The first is the triple degeneracy of the phonon branches at the P and H points,a universal property of elemental body-centered-cubic(bcc)structures.The second is a relatively isotropic character of the phonon dispersions.When both are met,phonon–phonon scattering rates must vanish at the P and H points.The weak phonon–phonon scattering feature is also applicable to Mo and Cr.However,in other elemental bcc substances like Na,the isotropy condition is violated due to the unusually soft character of the lower transverse acoustic phonon branch along the Γ-N direction,opening emission channels and leading to much stronger phonon–phonon scattering.We also look into the distributions of electron meanfree paths(MFPs)at room temperature in tungsten,which can help engineer the resistivity of nanostructured W for applications such as interconnects.
