How species diverge into different lineages is a central issue in evolutionary biology.Despite the increasing evidence indicating that such divergences do not need geographic isolation,the correlation between lineage ...How species diverge into different lineages is a central issue in evolutionary biology.Despite the increasing evidence indicating that such divergences do not need geographic isolation,the correlation between lineage divergence and the adaptive ecological divergence of phenotype corresponding to distribution is still unknown.In addition,gene flow has been widely detected during and through such diverging processes.We used one widely distributed Aquilegia viridiflora complex as a model system to examine genomic differentiation and corresponding phenotypic variations along geographic gradients.Our phenotypic analyses of 20 populations from northwest to northeast China identified two phenotypic groups along the geographic cline.All examined traits are distinct from each other,although a few intermediate individuals occur in their contacting regions.We further sequenced the genomes of representative individuals of each population.However,four distinct genetic lineages were detected based on nuclear genomes.In particular,we recovered numerous genetic hybrids in the contact regions of four lineages.Gene flow is widespread and continuous between four lineages but much higher between contacting lineages than geographically isolated lineages.Gene flow and natural selection might result in inconsistency between heredity and phenotype.Moreover,many genes with fast lineage-specific mutations were identified to be involved in local adaptation.Our results suggest that both geographic isolation and local selection exerted by the environment and pollinators may together create geographic distributions of phenotypic variations as well as the underlying genomic divergences in numerous lineages.展开更多
高效的水氧化是实现大规模分解水制氢的瓶颈,开发稳定、经济、高效的水氧化催化剂是引人关注的.早在上世纪中期Ag^+作为水氧化催化剂就有报道,但尚未见Ag^+配合物作为分子基水氧化催化剂的报道.本课题组选择缺位多酸阴离子[H_3PW_(11)O_...高效的水氧化是实现大规模分解水制氢的瓶颈,开发稳定、经济、高效的水氧化催化剂是引人关注的.早在上世纪中期Ag^+作为水氧化催化剂就有报道,但尚未见Ag^+配合物作为分子基水氧化催化剂的报道.本课题组选择缺位多酸阴离子[H_3PW_(11)O_(39)]^(3-)作为配体,成功研制了银-多酸配合物[H3Ag~Ⅰ(H2O)PW_(11)O_(39)]3-(AgPW_(11))分子基水氧化催化剂,发现其对使用S_2O_8^(2-)化学氧化水具有很好的催化作用,这主要归功于多酸配体在传输电子和质子的作用,对理解催化氧化水的机理有重要学术价值.将分子基催化剂修饰到电极上是实现其电化学催化氧化水的必由之路.本文采用浸渍法将AgPW_(11)修饰到TiO_2电极上,成功制备了AgPW_(11)-TiO_2/ITO电极,并通过XRD,SEM,EDX技术对AgPW_(11)-TiO_2/ITO电极进行了表征.结果表明,AgPW_(11)被成功负载到TiO_2纳米粒子表面,它的引入使得TiO_2电极表面的纳米粒子平均尺寸由10–40 nm增加到15–60 nm.在0.1 mol L^(-1)Na_2SO_4电解质溶液中利用线性扫描伏安、计时电流和电化学阻抗技术研究了AgPW_(11)-TiO_2/ITO阳极催化氧化水的性能,结果发现,当施加偏压大于1.3 V vs.Ag/AgCl时,随电压升高,AgPW_(11)-TiO_2/ITO电极相比TiO_2/ITO电极有更显著的氧化电流;当施加偏压在1.5 V vs.Ag/Ag Cl时,AgPW_(11)-TiO_2/ITO电极氧化电流比TiO_2/ITO电极和AgNO_3-TiO_2/ITO电极分别高出10倍和2.5倍,这归因于AgPW_(11)-TiO_2/ITO电极上电极-电解质界面具有更低的电荷转移阻抗,也说明多酸阴离子配体在催化过程中能够更好地传输电子和质子.在光照条件(100 m W cm^(-2))下,AgPW_(11)-TiO_2/ITO电极有较高的阳极电流,但光电流并没有明显增加,这主要是由于修饰电极光生电子–空穴复合速率较快所致.AgPW_(11)-TiO_2/ITO阳极重复使用15次后,电流密度仍然高出TiO_2/ITO电极3倍以上,表明AgPW_(11)-TiO_2复合电极稳定性较好.在0.1 mol L^(-1)磷酸缓冲溶液体系中研究了AgPW_(11)在不同浓度、不同pH值和不同扫速下的循环伏安曲线.在1.1–1.6 V vs.Ag/AgCl扫描范围和100 mVs^(-1)扫速条件下,在1.23和1.31 V vs.Ag/Ag Cl处出现的一对氧化还原峰,归结为Ag~Ⅰ/Ag ~Ⅱ的1e氧化还原过程.在1.0–1.4 V vs.Ag/AgCl扫描范围内,随扫速由100增至900 m V s^(-1),阴极还原峰电位负移而阳极氧化峰电位正移,导致峰-峰电位差△Ep增加,而且氧化峰电流与还原峰电流与扫速平方根呈线性关系,说明该电极氧化还原过程受扩散控制.对Ag I/Ag ~Ⅱ的氧化还原过程,随着p H值由5.3增加到6.7,氧化还原峰电位负移,并且E_(pc)与pH值呈现线性关系,斜率为–0.08882,根据能斯特方程S=2.303RTm/(αn F),推测转移的质子数为1.由此可知,AgPW_(11)氧化是准可逆的、1电子和1质子转移过程.推测[H_3Ag ~ⅠIH_2O)PW_(11)O_(39)]^(3-)氧化生成的[H_2Ag~Ⅱ(H_2O)PW_(1)1O_(39)]^(3-)可能发生歧化反应,所生成[H3Ag~ⅢOPW_(1)1O_(39)]^(3-)进而氧化水放出氧气.展开更多
Ethylene regulates many aspects of plant growth and development.It is perceived by a family of ethylene receptors(ETRs)that have been well described.However,a full understanding of ETR function is complicated by funct...Ethylene regulates many aspects of plant growth and development.It is perceived by a family of ethylene receptors(ETRs)that have been well described.However,a full understanding of ETR function is complicated by functional redundancy between the receptor isoforms.Here,we characterize a new ETR,SlETR7,that was revealed by tomato genome sequencing.SlETR7 expression in tomato fruit pericarp increases when the fruit ripens and its expression is synchronized with the expression of SlETR1,SlETR2,and SlETR5 which occurs later in the ripening phase than the increase observed for SlETR3,SlETR4,and SlETR6.We uncovered an error in the SlETR7 sequence as documented in the ITAG 3 versions of the tomato genome which has now been corrected in ITAG 4,and we showed that it belongs to sub-family II.We also showed that SlETR7 specifically binds ethylene.Overexpression(OE)of SlETR7 resulted in earlier flowering,shorter plants,and smaller fruit than wild type.Knock-out(KO)mutants of SlETR7 produced more ethylene at breaker(Br)and Br+2 days stages compared to wild type(WT),but there were no other obvious changes in the plant and fruit in these mutant lines.We observed that expression of the other SlETRs is upregulated in fruit of SlETR7 KO mutants,which may explain the absence of obvious ripening phenotypes.Globally,these results show that SlETR7 is a functional ethylene receptor.More work is needed to better understand its specific roles related to the six other tomato ETRs.展开更多
The synthesis of amphiphilic aggregation-induced emission(AIE) dyes based organic nanoparticles has recently attracted increasing attention in the biomedical fields. These AIE dyes based nanoparticles could effectivel...The synthesis of amphiphilic aggregation-induced emission(AIE) dyes based organic nanoparticles has recently attracted increasing attention in the biomedical fields. These AIE dyes based nanoparticles could effectively overcome the aggregation caused quenching effect of conventional organic dyes, making them promising candidates for fabrication of ultrabright organic luminescent nanomaterials. In this work, AIE-active luminescent polymeric nanoparticles(4-NH_2-PEG-TPE-E LPNs) were facilely fabricated through Michael addition reaction between tetraphenylethene acrylate(TPE-E) and 4-arm-poly(ethylene glycol)-amine(4-NH_2-PEG) in rather mild ambient. The 4-NH_2-PEG can not only endow these AIE-active LPNs good water dispersibility, but also provide functional groups for further conjugation reaction. The size, morphology and luminescent properties of 4-NH_2-PEG-TPE-E LPNs were characterized by a series of techniques in detail. Results suggested that these AIE-active LPNs showed spherical morphology with diameter about 100–200 nm. The obtained 4-NH_2-PEG-TPE-E LPNs display high water dispersibility and strong fluorescence intensity because of their self assembly and AIE properties of TPE-E.Biological evaluation results demonstrated that 4-NH_2-PEG-TPE-E LPNs showed negative toxicity toward cancer cells and good fluorescent imaging performance. All of these features make 4-NH_2-PEG-TPE-E LPNs promising candidates for biological imaging and therapeutic applications.展开更多
With the increasing capacity of photovoltaic(PV)power plants connected to power systems, PV plants are often required to have some reactive power control capabilities to participate in reactive power regulation. React...With the increasing capacity of photovoltaic(PV)power plants connected to power systems, PV plants are often required to have some reactive power control capabilities to participate in reactive power regulation. Reactive power regulation of grid-connected PV inverters can be achieved using different control strategies. In this paper, the reactive power capability of inverters and the technical requirement of PV plants are analyzed. The reactive power capability of a 30 MW PV plant is evaluated against relevant technical standards using a new testing method proposed in this paper.展开更多
基金The research was supported by the National Natural Science Foundation of China(32070244)Fundamental Research Funds for the Central Universities.
文摘How species diverge into different lineages is a central issue in evolutionary biology.Despite the increasing evidence indicating that such divergences do not need geographic isolation,the correlation between lineage divergence and the adaptive ecological divergence of phenotype corresponding to distribution is still unknown.In addition,gene flow has been widely detected during and through such diverging processes.We used one widely distributed Aquilegia viridiflora complex as a model system to examine genomic differentiation and corresponding phenotypic variations along geographic gradients.Our phenotypic analyses of 20 populations from northwest to northeast China identified two phenotypic groups along the geographic cline.All examined traits are distinct from each other,although a few intermediate individuals occur in their contacting regions.We further sequenced the genomes of representative individuals of each population.However,four distinct genetic lineages were detected based on nuclear genomes.In particular,we recovered numerous genetic hybrids in the contact regions of four lineages.Gene flow is widespread and continuous between four lineages but much higher between contacting lineages than geographically isolated lineages.Gene flow and natural selection might result in inconsistency between heredity and phenotype.Moreover,many genes with fast lineage-specific mutations were identified to be involved in local adaptation.Our results suggest that both geographic isolation and local selection exerted by the environment and pollinators may together create geographic distributions of phenotypic variations as well as the underlying genomic divergences in numerous lineages.
基金supported by the National Natural Science Foundation of China (21573100, 21573099) the Open Project of State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences (N-14-04)~~
基金supported by the National Natural Science Foundation of China (21573099, 21601077, 21573100)~~
文摘高效的水氧化是实现大规模分解水制氢的瓶颈,开发稳定、经济、高效的水氧化催化剂是引人关注的.早在上世纪中期Ag^+作为水氧化催化剂就有报道,但尚未见Ag^+配合物作为分子基水氧化催化剂的报道.本课题组选择缺位多酸阴离子[H_3PW_(11)O_(39)]^(3-)作为配体,成功研制了银-多酸配合物[H3Ag~Ⅰ(H2O)PW_(11)O_(39)]3-(AgPW_(11))分子基水氧化催化剂,发现其对使用S_2O_8^(2-)化学氧化水具有很好的催化作用,这主要归功于多酸配体在传输电子和质子的作用,对理解催化氧化水的机理有重要学术价值.将分子基催化剂修饰到电极上是实现其电化学催化氧化水的必由之路.本文采用浸渍法将AgPW_(11)修饰到TiO_2电极上,成功制备了AgPW_(11)-TiO_2/ITO电极,并通过XRD,SEM,EDX技术对AgPW_(11)-TiO_2/ITO电极进行了表征.结果表明,AgPW_(11)被成功负载到TiO_2纳米粒子表面,它的引入使得TiO_2电极表面的纳米粒子平均尺寸由10–40 nm增加到15–60 nm.在0.1 mol L^(-1)Na_2SO_4电解质溶液中利用线性扫描伏安、计时电流和电化学阻抗技术研究了AgPW_(11)-TiO_2/ITO阳极催化氧化水的性能,结果发现,当施加偏压大于1.3 V vs.Ag/AgCl时,随电压升高,AgPW_(11)-TiO_2/ITO电极相比TiO_2/ITO电极有更显著的氧化电流;当施加偏压在1.5 V vs.Ag/Ag Cl时,AgPW_(11)-TiO_2/ITO电极氧化电流比TiO_2/ITO电极和AgNO_3-TiO_2/ITO电极分别高出10倍和2.5倍,这归因于AgPW_(11)-TiO_2/ITO电极上电极-电解质界面具有更低的电荷转移阻抗,也说明多酸阴离子配体在催化过程中能够更好地传输电子和质子.在光照条件(100 m W cm^(-2))下,AgPW_(11)-TiO_2/ITO电极有较高的阳极电流,但光电流并没有明显增加,这主要是由于修饰电极光生电子–空穴复合速率较快所致.AgPW_(11)-TiO_2/ITO阳极重复使用15次后,电流密度仍然高出TiO_2/ITO电极3倍以上,表明AgPW_(11)-TiO_2复合电极稳定性较好.在0.1 mol L^(-1)磷酸缓冲溶液体系中研究了AgPW_(11)在不同浓度、不同pH值和不同扫速下的循环伏安曲线.在1.1–1.6 V vs.Ag/AgCl扫描范围和100 mVs^(-1)扫速条件下,在1.23和1.31 V vs.Ag/Ag Cl处出现的一对氧化还原峰,归结为Ag~Ⅰ/Ag ~Ⅱ的1e氧化还原过程.在1.0–1.4 V vs.Ag/AgCl扫描范围内,随扫速由100增至900 m V s^(-1),阴极还原峰电位负移而阳极氧化峰电位正移,导致峰-峰电位差△Ep增加,而且氧化峰电流与还原峰电流与扫速平方根呈线性关系,说明该电极氧化还原过程受扩散控制.对Ag I/Ag ~Ⅱ的氧化还原过程,随着p H值由5.3增加到6.7,氧化还原峰电位负移,并且E_(pc)与pH值呈现线性关系,斜率为–0.08882,根据能斯特方程S=2.303RTm/(αn F),推测转移的质子数为1.由此可知,AgPW_(11)氧化是准可逆的、1电子和1质子转移过程.推测[H_3Ag ~ⅠIH_2O)PW_(11)O_(39)]^(3-)氧化生成的[H_2Ag~Ⅱ(H_2O)PW_(1)1O_(39)]^(3-)可能发生歧化反应,所生成[H3Ag~ⅢOPW_(1)1O_(39)]^(3-)进而氧化水放出氧气.
文摘Ethylene regulates many aspects of plant growth and development.It is perceived by a family of ethylene receptors(ETRs)that have been well described.However,a full understanding of ETR function is complicated by functional redundancy between the receptor isoforms.Here,we characterize a new ETR,SlETR7,that was revealed by tomato genome sequencing.SlETR7 expression in tomato fruit pericarp increases when the fruit ripens and its expression is synchronized with the expression of SlETR1,SlETR2,and SlETR5 which occurs later in the ripening phase than the increase observed for SlETR3,SlETR4,and SlETR6.We uncovered an error in the SlETR7 sequence as documented in the ITAG 3 versions of the tomato genome which has now been corrected in ITAG 4,and we showed that it belongs to sub-family II.We also showed that SlETR7 specifically binds ethylene.Overexpression(OE)of SlETR7 resulted in earlier flowering,shorter plants,and smaller fruit than wild type.Knock-out(KO)mutants of SlETR7 produced more ethylene at breaker(Br)and Br+2 days stages compared to wild type(WT),but there were no other obvious changes in the plant and fruit in these mutant lines.We observed that expression of the other SlETRs is upregulated in fruit of SlETR7 KO mutants,which may explain the absence of obvious ripening phenotypes.Globally,these results show that SlETR7 is a functional ethylene receptor.More work is needed to better understand its specific roles related to the six other tomato ETRs.
基金supported by the National Natural Science Foundation of China (21134004, 21201108, 51363016, 21474057, 21564006, 21561022)the National Basic Research Program (2011CB935700)
文摘The synthesis of amphiphilic aggregation-induced emission(AIE) dyes based organic nanoparticles has recently attracted increasing attention in the biomedical fields. These AIE dyes based nanoparticles could effectively overcome the aggregation caused quenching effect of conventional organic dyes, making them promising candidates for fabrication of ultrabright organic luminescent nanomaterials. In this work, AIE-active luminescent polymeric nanoparticles(4-NH_2-PEG-TPE-E LPNs) were facilely fabricated through Michael addition reaction between tetraphenylethene acrylate(TPE-E) and 4-arm-poly(ethylene glycol)-amine(4-NH_2-PEG) in rather mild ambient. The 4-NH_2-PEG can not only endow these AIE-active LPNs good water dispersibility, but also provide functional groups for further conjugation reaction. The size, morphology and luminescent properties of 4-NH_2-PEG-TPE-E LPNs were characterized by a series of techniques in detail. Results suggested that these AIE-active LPNs showed spherical morphology with diameter about 100–200 nm. The obtained 4-NH_2-PEG-TPE-E LPNs display high water dispersibility and strong fluorescence intensity because of their self assembly and AIE properties of TPE-E.Biological evaluation results demonstrated that 4-NH_2-PEG-TPE-E LPNs showed negative toxicity toward cancer cells and good fluorescent imaging performance. All of these features make 4-NH_2-PEG-TPE-E LPNs promising candidates for biological imaging and therapeutic applications.
文摘With the increasing capacity of photovoltaic(PV)power plants connected to power systems, PV plants are often required to have some reactive power control capabilities to participate in reactive power regulation. Reactive power regulation of grid-connected PV inverters can be achieved using different control strategies. In this paper, the reactive power capability of inverters and the technical requirement of PV plants are analyzed. The reactive power capability of a 30 MW PV plant is evaluated against relevant technical standards using a new testing method proposed in this paper.
