The clustered regularly interspaced short palindromic repeats(CRISPR)–CRISPR-associated protein(Cas) system has been widely used for genome editing. In this system, the cytosine base editor(CBE) and adenine base edit...The clustered regularly interspaced short palindromic repeats(CRISPR)–CRISPR-associated protein(Cas) system has been widely used for genome editing. In this system, the cytosine base editor(CBE) and adenine base editor(ABE) allow generating precise and irreversible base mutations in a programmable manner and have been used in many different types of cells and organisms. However, their applications are limited by low editing efficiency at certain genomic target sites or at specific target cytosine(C) or adenine(A) residues. Using a strategy of combining optimized synergistic core components, we developed a new multiplex super-assembled ABE(sABE) in rice that showed higher base-editing efficiency than previously developed ABEs. We also designed a new type of nuclear localization signal(NLS) comprising a FLAG epitope tag with four copies of a codon-optimized NLS(F4NLS^(r2)) to generate another ABE named F4NLS-sABE. This new NLS increased editing efficiency or edited additional A at several target sites. A new multiplex super-assembled CBE(sCBE) and F4NLS^(r2) involved F4NLS-sCBE were also created using the same strategy. F4NLS-sCBE was proven to be much more efficient than sCBE in rice. These optimized base editors will serve as powerful genome-editing tools for basic research or molecular breeding in rice and will provide a reference for the development of superior editing tools for other plants or animals.展开更多
The noble metal Pt is an ideal catalyst for promoting the hydrogen evolution reaction(HER)during the electrolysis of water.However,Pt is also expensive and suffers from low utilization rates.In this work,a Pt-Ni_(2)P/...The noble metal Pt is an ideal catalyst for promoting the hydrogen evolution reaction(HER)during the electrolysis of water.However,Pt is also expensive and suffers from low utilization rates.In this work,a Pt-Ni_(2)P/NF nanorod catalyst with a low Pt loading was synthesized under different magnetic fields,and it was found that the application of a magnetic field can increase the rate of the galvanic replacement reaction.When the magnetic field strength increases from 0 to 600 mT,the chemical reaction rate increases gradually,and the utilization rate of Pt increased by 2.3 times under 600 mT.The mechanism of the magnetic field-induced magnetohydrodynamic(MHD)effect on the galvanic replacement reaction was revealed.In a 1 M KOH solution and at a current density of 10 mA cm^(-2),the overpotential of Pt-Ni_(2)P/NF prepared by applying a 600 mT magnetic field was as low as 15 mV and the Tafel slope was 37 mV dec^(-1),compared with values of 82 mV and 70 mV dec^(-1) for a specimen prepared without a magnetic field.Additionally,at an overpotential of 90 mV,the mass-based Pt activity of the former material was 12 times greater while its turnover frequency was 19 times greater.This work provides theoretical and technical knowledge expected to assist in the controllable preparation of materials in magnetic fields and the efficient utilization of metallic resources.展开更多
The design of electrode materials with specific structures is considered a promising approach for improving the performance of lithium-ion batteries(LIBs).In this paper,FeO/CoO hollow nanocages coated with a N-doped c...The design of electrode materials with specific structures is considered a promising approach for improving the performance of lithium-ion batteries(LIBs).In this paper,FeO/CoO hollow nanocages coated with a N-doped carbon layer(FCO@NC)was prepared using Fe-Co-based Prussian blue analogs(PBA)as a precursor.During the synthesis,dopamine was the carbon and nitrogen source.The reducing atmosphere was assured via NH_3/Ar,which regulated the vacancies in the structure of FCO@NC as well as increased its conductivity.When used as anode materials for LIBs,the FCO@NC nanocages deliver a high reversible capacity of 774.89 mAh·g^(-1)at 0.3 A·g^(-1)after200 cycles with a capacity retention rate of 80.4%and426.76 mAh·g^(-1)after 500 cycles at a high current density of 1 A·g^(-1).It is demonstrated that the hollow nanocage structure can effectively enhance the cycle stability,and the heat treatment in NH_(3)/Ar atmosphere contributes to the oxygen vacancy content of the electrode materials,further facilitating its conductivity and electrochemical performance.展开更多
The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still chal...The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still challenging. In this study, an efficient surrogate reporter system based on a defective hygromycin resistance gene was established in rice to enrich base-edited cells. After step-by-step optimization, the Discriminated sgRNAs-based SurroGate system (DisSUGs) was established by artificially differentiating the editing abilities of a wild-type single guide RNA (sgRNA) targeting the surrogate reporter gene and an enhanced sgRNA targeting endogenous sites. The DisSUGs enhanced the efficiency of screening base-edited cells by 3- to 5-fold for a PmCDA1-based cytosine-to-tyrosine base editor (PCBE), and 2.5- to 6.5-fold for an adenine base editor (ABE) at endogenous targets. These targets showed editing efficiencies of <25% in the conventional systems. The DisSUGs greatly enhanced the frequency of homozygous substitutions and expanded the activity window slightly for both a PCBE and an ABE. Analyses of the total number of single-nucleotide variants from whole-genome sequencing revealed that, compared with the no-enrichment PCBE strategy, the DisSUGs did not alter the frequency of genome-wide sgRNA-independent off-target mutations, but slightly increased the frequency of target-dependent off-target mutations. Collectively, the DisSUGs developed in this study greatly enhances the efficiency of screening plant base-edited cells and will be a useful system in future applications.展开更多
Fe3O4 is an attractive conversion reactionbased anode material with high theoretical capacity(928 mA h g-1).However,the poor cycling and rate performance hinder its applications in Li-ion batteries.In this work,we rep...Fe3O4 is an attractive conversion reactionbased anode material with high theoretical capacity(928 mA h g-1).However,the poor cycling and rate performance hinder its applications in Li-ion batteries.In this work,we report an effective strategy to synthesize threedimensionally macroporous graphene-supported Fe3O4hybrid composite.Benefiting from advantage of the special structure,the hybrid composite exhibits excellent Li+ storage performance,delivering a high reversible capacity of980 mA h g-1at the current density of 4 A g-1even after470 cycles and ultrahigh rate capability(293 mA h g-1even at current density of 20 A g-1).展开更多
We measured the contact angles of Al and Sn drops on polycrystalline Al2O3 substrates in various high magnetic fields at different temperatures.The contact angles of both Al and Sn drops on the Al2O3 substrates decrea...We measured the contact angles of Al and Sn drops on polycrystalline Al2O3 substrates in various high magnetic fields at different temperatures.The contact angles of both Al and Sn drops on the Al2O3 substrates decreased under high magnetic fields.These decreases strongly depend on the temperature,magnetic flux density,magnetic properties of the metal drops,and the reactivity of the metal drops with Al2O3.Our results reveal that the wetting behavior of molten metal drops on ceramics can be modified by a high magnetic field.展开更多
Flexible,lightweight and high conductivity substrates are required for the development of next-generation flexible Li-ion batteries(LIBs).In addition,the interfacial strength between the active material and flexible s...Flexible,lightweight and high conductivity substrates are required for the development of next-generation flexible Li-ion batteries(LIBs).In addition,the interfacial strength between the active material and flexible substrate should be optimized for high-performance LIBs.Herein,cotton cloth(CC)is employed as a flexible substrate,and electroless plating is utilized to deposit a layer of Cu nanoparticles,which enhances the conductivity of CC and acts as a precursor for the active material,i.e.,CuO.The results reveal that the in situ etching and subsequent heat treatment converted Cu film into CuO nanowires on CC substrate.Moreover,carbon nano tubes(CNTs)are introduced to enhance the connectivity of CuO nano wires.Consequently,the CuO/CNT/CC electrode rendered a high areal capacity of>700μAh-cm^(-2)after100 charge/discharge cycles as well as excellent rate capability.The current work presents a novel route to develop desirable substrates for next-generation flexible Li-ion batteries.展开更多
Solar energy has been increasing its share in the global energy structure. However, the thermal radiation brought by sunlight will attenuate the efficiency of solar cells. To reduce the temperature of the photovoltaic...Solar energy has been increasing its share in the global energy structure. However, the thermal radiation brought by sunlight will attenuate the efficiency of solar cells. To reduce the temperature of the photovoltaic (PV) cell and improve the utilization efficiency of solar energy, a hybrid system composed of the PV cell, a thermoelectric generator (TEG), and a water-cooled plate (WCP) was manufactured. The WCP cannot only cool the PV cell, but also effectively generate additional electric energy with the TEG using the waste heat of the PV cell. The changes in the efficiency and power density of the hybrid system were obtained by real time monitoring. The thermal and electrical tests were performed at different irradiations and the same experiment temperature of 22°C. At a light intensity of 1000 W/m2, the steady-state temperature of the PV cell decreases from 86.8°C to 54.1°C, and the overall efficiency increases from 15.6% to 21.1%. At a light intensity of 800 W/m2, the steady-state temperature of the PV cell decreases from 70°C to 45.8°C, and the overall efficiency increases from 9.28% to 12.59%. At a light intensity of 400 W/m2, the steady-state temperature of the PV cell decreases from 38.5°C to 31.5°C, and the overall efficiency is approximately 3.8%, basically remain unchanged.展开更多
The morphology evolution and magnetic properties of Co films–native oxide Si(100)were investigated at 873,973,and 1073 K in a high magnetic field of 11.5 T.Formation of Kirkendall voids in the Co films was found to c...The morphology evolution and magnetic properties of Co films–native oxide Si(100)were investigated at 873,973,and 1073 K in a high magnetic field of 11.5 T.Formation of Kirkendall voids in the Co films was found to cause morphology evolution due to the difference in diffusion flux of Co and Si atoms through the native oxide layer.The high magnetic fields had considerable effect on the morphology evolution by accelerating nanoscale Kirkendall effect.The diffusion mechanism in the presence of high magnetic fields was given to explain the increase of diffusion coefficient.The morphology evolution of Co films on native oxide Si(100)under high magnetic fields during annealing resulted in the magnetic properties variation.展开更多
基金supported by the Beijing Scholars Program[BSP041]。
文摘The clustered regularly interspaced short palindromic repeats(CRISPR)–CRISPR-associated protein(Cas) system has been widely used for genome editing. In this system, the cytosine base editor(CBE) and adenine base editor(ABE) allow generating precise and irreversible base mutations in a programmable manner and have been used in many different types of cells and organisms. However, their applications are limited by low editing efficiency at certain genomic target sites or at specific target cytosine(C) or adenine(A) residues. Using a strategy of combining optimized synergistic core components, we developed a new multiplex super-assembled ABE(sABE) in rice that showed higher base-editing efficiency than previously developed ABEs. We also designed a new type of nuclear localization signal(NLS) comprising a FLAG epitope tag with four copies of a codon-optimized NLS(F4NLS^(r2)) to generate another ABE named F4NLS-sABE. This new NLS increased editing efficiency or edited additional A at several target sites. A new multiplex super-assembled CBE(sCBE) and F4NLS^(r2) involved F4NLS-sCBE were also created using the same strategy. F4NLS-sCBE was proven to be much more efficient than sCBE in rice. These optimized base editors will serve as powerful genome-editing tools for basic research or molecular breeding in rice and will provide a reference for the development of superior editing tools for other plants or animals.
基金financially supported by the National Natural Science Foundation of China(Grant No.52274294)the Fundamental Research Funds for the Central Universities(Grant No.N2124007-1).
文摘The noble metal Pt is an ideal catalyst for promoting the hydrogen evolution reaction(HER)during the electrolysis of water.However,Pt is also expensive and suffers from low utilization rates.In this work,a Pt-Ni_(2)P/NF nanorod catalyst with a low Pt loading was synthesized under different magnetic fields,and it was found that the application of a magnetic field can increase the rate of the galvanic replacement reaction.When the magnetic field strength increases from 0 to 600 mT,the chemical reaction rate increases gradually,and the utilization rate of Pt increased by 2.3 times under 600 mT.The mechanism of the magnetic field-induced magnetohydrodynamic(MHD)effect on the galvanic replacement reaction was revealed.In a 1 M KOH solution and at a current density of 10 mA cm^(-2),the overpotential of Pt-Ni_(2)P/NF prepared by applying a 600 mT magnetic field was as low as 15 mV and the Tafel slope was 37 mV dec^(-1),compared with values of 82 mV and 70 mV dec^(-1) for a specimen prepared without a magnetic field.Additionally,at an overpotential of 90 mV,the mass-based Pt activity of the former material was 12 times greater while its turnover frequency was 19 times greater.This work provides theoretical and technical knowledge expected to assist in the controllable preparation of materials in magnetic fields and the efficient utilization of metallic resources.
基金financially supported by the National Natural Science Foundation of China (No.52274294)the Fundamental Research Funds for the Central Universities (No.N2124007-1)。
文摘The design of electrode materials with specific structures is considered a promising approach for improving the performance of lithium-ion batteries(LIBs).In this paper,FeO/CoO hollow nanocages coated with a N-doped carbon layer(FCO@NC)was prepared using Fe-Co-based Prussian blue analogs(PBA)as a precursor.During the synthesis,dopamine was the carbon and nitrogen source.The reducing atmosphere was assured via NH_3/Ar,which regulated the vacancies in the structure of FCO@NC as well as increased its conductivity.When used as anode materials for LIBs,the FCO@NC nanocages deliver a high reversible capacity of 774.89 mAh·g^(-1)at 0.3 A·g^(-1)after200 cycles with a capacity retention rate of 80.4%and426.76 mAh·g^(-1)after 500 cycles at a high current density of 1 A·g^(-1).It is demonstrated that the hollow nanocage structure can effectively enhance the cycle stability,and the heat treatment in NH_(3)/Ar atmosphere contributes to the oxygen vacancy content of the electrode materials,further facilitating its conductivity and electrochemical performance.
基金This work was supported by Beijing Academy of Agriculture&Forestry Scien ces,Beijing,ChinaThe funding in eluded Innovative Team Con-struction Project of BAAFS(JNKYT201603)the Beijing Scholars Program(BSP041).
文摘The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still challenging. In this study, an efficient surrogate reporter system based on a defective hygromycin resistance gene was established in rice to enrich base-edited cells. After step-by-step optimization, the Discriminated sgRNAs-based SurroGate system (DisSUGs) was established by artificially differentiating the editing abilities of a wild-type single guide RNA (sgRNA) targeting the surrogate reporter gene and an enhanced sgRNA targeting endogenous sites. The DisSUGs enhanced the efficiency of screening base-edited cells by 3- to 5-fold for a PmCDA1-based cytosine-to-tyrosine base editor (PCBE), and 2.5- to 6.5-fold for an adenine base editor (ABE) at endogenous targets. These targets showed editing efficiencies of <25% in the conventional systems. The DisSUGs greatly enhanced the frequency of homozygous substitutions and expanded the activity window slightly for both a PCBE and an ABE. Analyses of the total number of single-nucleotide variants from whole-genome sequencing revealed that, compared with the no-enrichment PCBE strategy, the DisSUGs did not alter the frequency of genome-wide sgRNA-independent off-target mutations, but slightly increased the frequency of target-dependent off-target mutations. Collectively, the DisSUGs developed in this study greatly enhances the efficiency of screening plant base-edited cells and will be a useful system in future applications.
基金supported by the Program of ‘‘One Hundred Talents People’’ of the Chinese Academy of Sciencesthe National Basic Research Program of China (2012CB215500)+2 种基金the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (20921002)the National Natural Science Foundation of China (21101147)the Jilin Provincial Science and Technology Development Program (20100102,20116008)
文摘Fe3O4 is an attractive conversion reactionbased anode material with high theoretical capacity(928 mA h g-1).However,the poor cycling and rate performance hinder its applications in Li-ion batteries.In this work,we report an effective strategy to synthesize threedimensionally macroporous graphene-supported Fe3O4hybrid composite.Benefiting from advantage of the special structure,the hybrid composite exhibits excellent Li+ storage performance,delivering a high reversible capacity of980 mA h g-1at the current density of 4 A g-1even after470 cycles and ultrahigh rate capability(293 mA h g-1even at current density of 20 A g-1).
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51774086,51574073,51425401,and 51690161)Fundamental Research Funds for the Central Universities(Grant Nos.N180915002,N170902002 and N170908001)Liaoning Innovative Research Team in University,China(Grant No.LT2017011).
文摘We measured the contact angles of Al and Sn drops on polycrystalline Al2O3 substrates in various high magnetic fields at different temperatures.The contact angles of both Al and Sn drops on the Al2O3 substrates decreased under high magnetic fields.These decreases strongly depend on the temperature,magnetic flux density,magnetic properties of the metal drops,and the reactivity of the metal drops with Al2O3.Our results reveal that the wetting behavior of molten metal drops on ceramics can be modified by a high magnetic field.
基金the National Natural Science Foundation of China(Nos.21701022 and51690161)the Fundamental Research Funds for the Central Universities(Nos.N182505037 and N182410001)+2 种基金the Young Elite Scientists Sponsorship Program by CAST(No.2018QNRC001)the Liao Ning Revitalization Talents Program(No.XLYC1807214)the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.201910145260)。
文摘Flexible,lightweight and high conductivity substrates are required for the development of next-generation flexible Li-ion batteries(LIBs).In addition,the interfacial strength between the active material and flexible substrate should be optimized for high-performance LIBs.Herein,cotton cloth(CC)is employed as a flexible substrate,and electroless plating is utilized to deposit a layer of Cu nanoparticles,which enhances the conductivity of CC and acts as a precursor for the active material,i.e.,CuO.The results reveal that the in situ etching and subsequent heat treatment converted Cu film into CuO nanowires on CC substrate.Moreover,carbon nano tubes(CNTs)are introduced to enhance the connectivity of CuO nano wires.Consequently,the CuO/CNT/CC electrode rendered a high areal capacity of>700μAh-cm^(-2)after100 charge/discharge cycles as well as excellent rate capability.The current work presents a novel route to develop desirable substrates for next-generation flexible Li-ion batteries.
基金This work is financially supported by the fundamental research funds for the central universities, the National Natural Science Foundation of China （Grant Nos. 51372007 and 21301014）.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.51690161 and 21701022)the Fundamental Research Funds for the Central Universities(Grant Nos.N182505037 and N2025035)+1 种基金the Young Elite Scientists Sponsorship Program by CAST(Grant No.2018QNRC001)the Liaoning Revitalization Talents Program(Grant No.XLYC1807214).
文摘Solar energy has been increasing its share in the global energy structure. However, the thermal radiation brought by sunlight will attenuate the efficiency of solar cells. To reduce the temperature of the photovoltaic (PV) cell and improve the utilization efficiency of solar energy, a hybrid system composed of the PV cell, a thermoelectric generator (TEG), and a water-cooled plate (WCP) was manufactured. The WCP cannot only cool the PV cell, but also effectively generate additional electric energy with the TEG using the waste heat of the PV cell. The changes in the efficiency and power density of the hybrid system were obtained by real time monitoring. The thermal and electrical tests were performed at different irradiations and the same experiment temperature of 22°C. At a light intensity of 1000 W/m2, the steady-state temperature of the PV cell decreases from 86.8°C to 54.1°C, and the overall efficiency increases from 15.6% to 21.1%. At a light intensity of 800 W/m2, the steady-state temperature of the PV cell decreases from 70°C to 45.8°C, and the overall efficiency increases from 9.28% to 12.59%. At a light intensity of 400 W/m2, the steady-state temperature of the PV cell decreases from 38.5°C to 31.5°C, and the overall efficiency is approximately 3.8%, basically remain unchanged.
基金the National Natural Science Foundation of China(Nos.51425401,51690162)Liaoning Innovative Research Team in University(No.LT2017011)the Fundamental Research Funds for the Central Universities(Nos.N160907001,N180915002 and N180912004)。
文摘The morphology evolution and magnetic properties of Co films–native oxide Si(100)were investigated at 873,973,and 1073 K in a high magnetic field of 11.5 T.Formation of Kirkendall voids in the Co films was found to cause morphology evolution due to the difference in diffusion flux of Co and Si atoms through the native oxide layer.The high magnetic fields had considerable effect on the morphology evolution by accelerating nanoscale Kirkendall effect.The diffusion mechanism in the presence of high magnetic fields was given to explain the increase of diffusion coefficient.The morphology evolution of Co films on native oxide Si(100)under high magnetic fields during annealing resulted in the magnetic properties variation.
