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The macrodomain family:Rethinking an ancient domain from evolutionary perspectives
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作者 LI XiaoLei WU ZhiQiang HAN WeiDong 《Chinese Science Bulletin》 SCIE EI CAS 2013年第9期953-960,共8页
The reasons why certain domains evolve much slower than others is unclear.The notion that functionally more important genes evolve more slowly than less important genes is one of the few commonly believed principles o... The reasons why certain domains evolve much slower than others is unclear.The notion that functionally more important genes evolve more slowly than less important genes is one of the few commonly believed principles of molecular evolution.The macrodomain(also known as the X domain) is an ancient,slowly evolving and highly conserved structural domain found in proteins throughout all of the kingdoms and was first discovered nearly two decades ago with the isolation and cloning of macroH2A1.Macrodomains,which are functionally promiscuous,have been studied intensively for the past decade due to their importance in the regulation of cellular responses to DNA damage,chromatin remodeling,transcription and tumorigenesis.Recent structural,phylogenetic and biological analyses,however,suggest the need for some reconsideration of the evolutionary advantage of concentrating such a plethora of diverse functions into the macrodomain and of how macrodomains could perform so many functions.In this article,we focus on macrodomains that are evolving slowly and broadly discuss the potential relationship between the biological evolution and functional diversity of macrodomains. 展开更多
关键词 基因进化 宏畴 家庭 DNA损伤 染色质重塑 生物学分析 功能多样性 分子进化
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弛豫铁电体的微畴-宏畴转变与生长动力学 被引量:1
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作者 张栋杰 姚熹 《物理化学学报》 SCIE CAS CSCD 北大核心 2004年第7期712-716,共5页
制备了铅基弛豫铁电体0.9 Pb(Mg1/3Nb2/3)O3-0.1 PbTiO3和Pb(Zn1/3Nb2/3)O3基陶瓷.利用修正的局域冻结玻璃模型研究了弛豫铁电体微畴-宏畴转变动力学和微畴生长动力学,结果表明,微畴-宏畴转变过程是量子化的过程,微畴-宏畴转变的驱动力... 制备了铅基弛豫铁电体0.9 Pb(Mg1/3Nb2/3)O3-0.1 PbTiO3和Pb(Zn1/3Nb2/3)O3基陶瓷.利用修正的局域冻结玻璃模型研究了弛豫铁电体微畴-宏畴转变动力学和微畴生长动力学,结果表明,微畴-宏畴转变过程是量子化的过程,微畴-宏畴转变的驱动力主要是热驱动力和能量驱动力,微畴-宏畴转变稳定性由活化能和状态数来判断,而微畴生长动力学的稳定性可以用稳定性判据值大小确定. 展开更多
关键词 弛豫铁电体 微畴 宏畴 生长 动力学
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铌锌酸铅基陶瓷的电致伸缩特性与极化机制
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作者 樊慧庆 虞利军 +1 位作者 张良莹 姚熹 《材料研究学报》 EI CAS CSCD 北大核心 1997年第5期543-546,共4页
系统地测试了铌锌酸铅基系列陶瓷PZN-BT-PT(85-10-5,80-10-10,75-10-15)的电致伸缩应变、电滞回线和介电性能研究了它们的电诱应变同极化强度关果结合介电温谱的结果,阐明铁电体微畴、宏畴对铁电陶瓷电致伸缩特性的作用.... 系统地测试了铌锌酸铅基系列陶瓷PZN-BT-PT(85-10-5,80-10-10,75-10-15)的电致伸缩应变、电滞回线和介电性能研究了它们的电诱应变同极化强度关果结合介电温谱的结果,阐明铁电体微畴、宏畴对铁电陶瓷电致伸缩特性的作用.发现铁电微畴在交流小信号测量中所表现的介电弛豫特征在强场测量中消失。 展开更多
关键词 铁电陶瓷 电致伸缩 弛豫 微畴-宏畴
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弛豫铁电体微畴-宏畴转变稳定性的一种新判据
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作者 张栋杰 程忠阳 +1 位作者 张良莹 姚熹 《压电与声光》 CAS CSCD 北大核心 1998年第6期414-418,共5页
利用铅基弛豫铁电体的局域冻结模型和Vogel-Fulcherg模型,求出了铅基弛豫铁电体的活化能、频率因子和冻结温度。并在此基础上提出了动态跃迁频率作为微畴-宏畴转变稳定性的新判据。动态跃迁频率越小,微畴向宏畴转变越... 利用铅基弛豫铁电体的局域冻结模型和Vogel-Fulcherg模型,求出了铅基弛豫铁电体的活化能、频率因子和冻结温度。并在此基础上提出了动态跃迁频率作为微畴-宏畴转变稳定性的新判据。动态跃迁频率越小,微畴向宏畴转变越困难,即微畴越稳定。此判据同时考虑了动力学因素和活化能,具有普适性。 展开更多
关键词 弛豫铁电体 微畴-宏畴 玻璃模型
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ADP-ribosylhydrolases:from DNA damage repair to COVID-19
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作者 Lily YU Xiuhua LIU Xiaochun YU 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2021年第1期21-30,共10页
Adenosine diphosphate(ADP)-ribosylation is a unique post-translational modification that regulates many biological processes,such as DNA damage repair.During DNA repair,ADP-ribosylation needs to be reversed by ADP-rib... Adenosine diphosphate(ADP)-ribosylation is a unique post-translational modification that regulates many biological processes,such as DNA damage repair.During DNA repair,ADP-ribosylation needs to be reversed by ADP-ribosylhydrolases.A group of ADP-ribosylhydrolases have a catalytic domain,namely the macrodomain,which is conserved in evolution from prokaryotes to humans.Not all macrodomains remove ADP-ribosylation.One set of macrodomains loses enzymatic activity and only binds to ADP-ribose(ADPR).Here,we summarize the biological functions of these macrodomains in DNA damage repair and compare the structure of enzymatically active and inactive macrodomains.Moreover,small molecular inhibitors have been developed that target macrodomains to suppress DNA damage repair and tumor growth.Macrodomain proteins are also expressed in pathogens,such as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).However,these domains may not be directly involved in DNA damage repair in the hosts or pathogens.Instead,they play key roles in pathogen replication.Thus,by targeting macrodomains it may be possible to treat pathogen-induced diseases,such as coronavirus disease 2019(COVID-19). 展开更多
关键词 DNA damage repair Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) Adenosine diphosphate(ADP)-ribosylation macrodomain ADP-ribosylhydrolase deADP-ribosylation
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La掺杂诱发层状钙钛矿型铁电体弛豫性相变的介电研究 被引量:11
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作者 惠荣 朱骏 +3 位作者 卢网平 毛翔宇 羌锋 陈小兵 《物理学报》 SCIE EI CAS CSCD 北大核心 2004年第1期276-281,共6页
制备了La掺杂层状钙钛矿铁电体材料SrBi4 Ti4 O1 5,Sr2 Bi4 Ti5O1 8以及共生结构Bi4 Ti3O1 2 SrBi4 Ti4 O1 5,通过研究样品的变温介电特性发现 ,SrBi4 -xLaxTi4 O1 5(x=1 0 ) ,Sr2 Bi4 -xLaxTi5O1 8(x≥ 0 5 ) ,(Bi,La) 4Ti3O1 2 Sr(... 制备了La掺杂层状钙钛矿铁电体材料SrBi4 Ti4 O1 5,Sr2 Bi4 Ti5O1 8以及共生结构Bi4 Ti3O1 2 SrBi4 Ti4 O1 5,通过研究样品的变温介电特性发现 ,SrBi4 -xLaxTi4 O1 5(x=1 0 ) ,Sr2 Bi4 -xLaxTi5O1 8(x≥ 0 5 ) ,(Bi,La) 4Ti3O1 2 Sr(Bi,La) 4Ti4 O1 5(x=1 5 0 )样品的介电常数随温度变化曲线都具有弛豫性相变特征 ,La含量的变化对介电温度特性曲线有重要影响 ,随着La含量的增加 ,其弛豫程度明显增加 .弛豫的起源与La离子的存在引起局域出现的微畴有关 ,而正常铁电体—弛豫铁电体自发相变相对应的微观机理是正常铁电体的宏畴向弛豫铁电体微畴的转变 . 展开更多
关键词 镧掺杂 层状钙钛矿 铁电体 介电性能 弛豫性相变 介电常数 正常铁电体 弛豫铁电体
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Dielectric behavior of poled complex perovskite relaxor ferroelectrics 被引量:1
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作者 FAN Huiqing, XU Zhuo, ZHANG Liangying and YAO XiElectronic Materials Research Laboratory, Xi’an Jiaotong University, Xi’an 710049, China 《Chinese Science Bulletin》 SCIE EI CAS 1997年第2期169-172,共4页
RELAXOR ferroelectric ceramics with complex perovskite structure is considered as the first material chosen for multilayer capacitors (MLC) in technology and economy, because of their high permittivity, lower sinterin... RELAXOR ferroelectric ceramics with complex perovskite structure is considered as the first material chosen for multilayer capacitors (MLC) in technology and economy, because of their high permittivity, lower sintering temperature and lower capacitors changing rate with temperature (temperature coefficient) for diffuse phase transition (DPT). Thus, preparations and properties about the materials received more attention. There are many reports about their dielectric properties but there are few about their poled dielectric behavior. In the 展开更多
关键词 poled DIELECTRIC BEHAVIOR relaxor FERROELECTRICS microdomain-macrodomain.
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