Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the tr...Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium,ie.jet-quenching.Previous measurements revealed a strong modification to di-hadron azimuthal correlations in Au+Au collisions with respect to ptp and d+Au collisions.The modification in-creases with the collision centrality,suggesting a path-length or energy density dependence to the je-quenching ef-fect.This paper reports STAR measurements of dihadron azimuthal correlations in mid-central(20%-60%)Au+Au collisions at√^(S)NN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane,Ф_(s)=|Ф_(t)-ψ_(Ep)|.The azimuthal correlation is studied as a function of both the trigger and associated particle pr.The subtractions of the combinatorial background and anisotropic flow,assuming Zero Yield At Minimum(ZYAM),are described.The correlation results are first discussed with subtraction of the even harmonic(elliptic and quadrangu-lar)flow backgrounds.The away-side correlation is strongly modifed,and the modification varies withФ_(s),with a double-peak structure for out-of-plane trigger particles.The near-side ridge(long range pseudo-rapidity△_(η)correla-tion)appears to drop with increasingФ_(s)while the jet-like component remains approximately constant.The correla-tion functions are further studied with the subtraction of odd harmonic triangular flow background arising from fluc-tuations.It is found that the triangular flow,while responsible for the majority of the amplitudes,is not sufficient to explain theφs-dependence of the ridge or the away-side double-peak structure.The dropping ridge withФ_(s)could be attributed to aФ_(s)-dependent lliptie anisotropy;however,the physics mechanism of the ridge remains an open ques-tion.Even with aФ_(s)-dependent elliptic flow,the away-side correlation structure is robust.These results,with exte展开更多
CONSORT声明被广泛用于提高随机对照临床试验的报告质量。Kenneth Schulz等对CONSORT声明的最新版本CONSORT2010作了详细说明,该版本基于新获得的方法学证据和经验的积累对报告指南作了更新。为了鼓励更多的人使用"CONSORT2010声明...CONSORT声明被广泛用于提高随机对照临床试验的报告质量。Kenneth Schulz等对CONSORT声明的最新版本CONSORT2010作了详细说明,该版本基于新获得的方法学证据和经验的积累对报告指南作了更新。为了鼓励更多的人使用"CONSORT2010声明",本文可从bmj.com免费获取,也将在Lancet,Obstetrics and Gynecology,PLoS Medicine,Annals of Internal Medicine,Open Medicine,Journal of Clinical Epidemiology,BMC Medicine和Trials等杂志发表。展开更多
Highly active and low-cost catalysts for electrochemical reactions such as the hydrogen evolution reaction （HER） are crucial for the development of efficient energy conversion and storage technologies. Theoretical s...Highly active and low-cost catalysts for electrochemical reactions such as the hydrogen evolution reaction （HER） are crucial for the development of efficient energy conversion and storage technologies. Theoretical simulations have been instrumental in revealing the correlations between the electronic structure of materials and their catalytic activity, and guide the prediction and development of improved catalysts. However, difficulties in accurately engineering the desired atomic sites lead to challenges in making direct comparisons between experi- mental and theoretical results. In MoS2, the Mo-edge has been demonstrated to be active for HER whereas the S-edge is inert. Using a computational descriptor- based approach, we predict that by incorporating transition metal atoms （Fe, Co, Ni, or Cu） the S-edge site should also become HER active. Vertically standing, edge-terminated MoS2 nanofilms provide a well-defined model system for verifying these predictions. The transition metal doped MoS2 nanofilms show an increase in exchange current densities by at least two-fold, in agreement with the theoretical calculations. This work opens up further opportunities for improving electrochemical catalysts by incorporating promoters into particular atomic sites, and for using well-defined systems in order to understand the origin of the promotion effects.展开更多
The reactive force-field(ReaxFF)interatomic potential is a powerful computational tool for exploring,developing and optimizing material properties.Methods based on the principles of quantum mechanics(QM),while offerin...The reactive force-field(ReaxFF)interatomic potential is a powerful computational tool for exploring,developing and optimizing material properties.Methods based on the principles of quantum mechanics(QM),while offering valuable theoretical guidance at the electronic level,are often too computationally intense for simulations that consider the full dynamic evolution of a system.Alternatively,empirical interatomic potentials that are based on classical principles require significantly fewer computational resources,which enables simulations to better describe dynamic processes over longer timeframes and on larger scales.Such methods,however,typically require a predefined connectivity between atoms,precluding simulations that involve reactive events.The ReaxFF method was developed to help bridge this gap.Approaching the gap from the classical side,ReaxFF casts the empirical interatomic potential within a bond-order formalism,thus implicitly describing chemical bonding without expensive QM calculations.This article provides an overview of the development,application,and future directions of the ReaxFF method.展开更多
A parameterization of soil freezing-thawing physics for use in the land-surface model of the National Center for Atmospheric Research(NCAR) Community Climate Model(CCM3) is developed and evaluated.The new parameteriza...A parameterization of soil freezing-thawing physics for use in the land-surface model of the National Center for Atmospheric Research(NCAR) Community Climate Model(CCM3) is developed and evaluated.The new parameterization scheme has improved the representation of physical processes in the existing land surface model.Numerical simulations using CCM3 with improved land-surface processes and with the original land-surface processes are compared against the NCEP reanalysis.It is found that the CCM3 version using the improved land surface model shows significant improvements in simulating precipitation in China during the summer season,the general circulation over East Asia,and wind fields over the Tibet Plateau.For the summer season,the improved model was able to better simulate the Indian summer monsoon components,including the mean northerly wind in the upper troposphere and mean southerly wind in the lower troposphere.展开更多
Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multipl...Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multiple alleles of mpk4 and mekkl that exhibit cell death and constitutive defense responses. Bimolecular fluorescence complemen- tation （BiFC） analysis showed that both MPK4 and MEKK1 interact with MKK1 and MKK2, two closely related MAPK kinases, mkkl and mkk2 single mutant plants do not have obvious mutant phenotypes. To test whether MKK1 and MKK2 function redundantly, mkkl mkk2 double mutants were generated. The mkkl mkk2 double mutant plants die at seedling stage and the seedling-lethality phenotype is temperature-dependent. Similar to the mpk4 and mekkl mutants, the mkkl mkk2 double mutant seedlings accumulate high levels of H202, display spontaneous cell death, constitutively express Pathogenesis Related （PR） genes and exhibit pathogen resistance. In addition, activation of MPK4 by fig22 is impaired in the mkkl mkk2 double mutants, suggesting that MKK1 and MKK2 function together with MPK4 and MEKK1 in a MAP kinase cascade to negatively regulate innate immune responses in plants.展开更多
Dear Editor, RNA-guided genome editing （RGE） using the Streptococcus pyogenes CRISPR-Cas9 system （Jinek et al., 2012; Cong et al., 2013; Mall et al., 2013b） is emerging as a simple and highly efficient tool for ge...Dear Editor, RNA-guided genome editing （RGE） using the Streptococcus pyogenes CRISPR-Cas9 system （Jinek et al., 2012; Cong et al., 2013; Mall et al., 2013b） is emerging as a simple and highly efficient tool for genome editing in many organisms. The Cas9 nuclease can be programmed by dual or single guide RNA （gRNA） to cut target DNA at specific sites,展开更多
Superconductivity has been the focus of enormous research effort since its discovery more than a century ago.Yet,some features of this unique phenomenon remain poorly understood;prime among these is the connection bet...Superconductivity has been the focus of enormous research effort since its discovery more than a century ago.Yet,some features of this unique phenomenon remain poorly understood;prime among these is the connection between superconductivity and chemical/structural properties of materials.To bridge the gap,several machine learning schemes are developed herein to model the critical temperatures(T_(c))of the 12,000+known superconductors available via the SuperCon database.Materials are first divided into two classes based on their T_(c) values,above and below 10 K,and a classification model predicting this label is trained.The model uses coarse-grained features based only on the chemical compositions.It shows strong predictive power,with out-of-sample accuracy of about 92%.Separate regression models are developed to predict the values of T_(c) for cuprate,iron-based,and low-T_(c) compounds.These models also demonstrate good performance,with learned predictors offering potential insights into the mechanisms behind superconductivity in different families of materials.To improve the accuracy and interpretability of these models,new features are incorporated using materials data from the AFLOW Online Repositories.Finally,the classification and regression models are combined into a single-integrated pipeline and employed to search the entire Inorganic Crystallographic Structure Database(ICSD)for potential new superconductors.We identify>30 non-cuprate and non-iron-based oxides as candidate materials.展开更多
The Materials Genome Initiative(MGI)advanced a new paradigm for materials discovery and design,namely that the pace of new materials deployment could be accelerated through complementary efforts in theory,computation,...The Materials Genome Initiative(MGI)advanced a new paradigm for materials discovery and design,namely that the pace of new materials deployment could be accelerated through complementary efforts in theory,computation,and experiment.Along with numerous successes,new challenges are inviting researchers to refocus the efforts and approaches that were originally inspired by the MGI.In May 2017,the National Science Foundation sponsored the workshop“Advancing and Accelerating Materials Innovation Through the Synergistic Interaction among Computation,Experiment,and Theory:Opening New Frontiers”to review accomplishments that emerged from investments in science and infrastructure under the MGI,identify scientific opportunities in this new environment,examine how to effectively utilize new materials innovation infrastructure,and discuss challenges in achieving accelerated materials research through the seamless integration of experiment,computation,and theory.This article summarizes key findings from the workshop and provides perspectives that aim to guide the direction of future materials research and its translation into societal impacts.展开更多
We describe a call for an international coordinated effort in rice functional genomics in the form of a project named RICE2020. The mission of the project will be： to determine the function of every gene in the rice ...We describe a call for an international coordinated effort in rice functional genomics in the form of a project named RICE2020. The mission of the project will be： to determine the function of every gene in the rice genome by the year 2020, to identify functional diversity of alleles for agriculturally useful genes from the primary gene pool of rice, and to apply the findings of functional genomics research to rice genetic improvement.展开更多
Mitogen-activated protein kinase （MAPK） and leucine-rich repeat receptor-like kinase （LRR-RLK） signaling pathways have been shown to regulate diverse aspects of plant growth and development. In Arabidopsis, proper...Mitogen-activated protein kinase （MAPK） and leucine-rich repeat receptor-like kinase （LRR-RLK） signaling pathways have been shown to regulate diverse aspects of plant growth and development. In Arabidopsis, proper anther development relies on intercellular communication to coordinate cell proliferation and differentiation. Two closely related genes encoding MAPKs, MPK3 and MPK6, function redundantly in regulating stomatal patterning. Although the mpk6 mutant has reduced fertility, the function of MPK3 and MPK6 in anther development has not been characterized. Similarly, the ERECTA （ER）, ERECTA-LIKE1 （ERL1） and ERL2 genes encoding LRR-RLKs function together to direct stomatal cell fate specification and the er-105 erll-2 erl2-1 triple mutant is sterile. Because the mpk3 rnpk6 double null mutant is embryo lethal, anther development was characterized in the viable mpk3/＋ mpk6/- and er-105 erll-2 erl2-1 mutants. We found that both mutant anthers usually fail to form one or more of the four anther lobes, with the er-105 erl1-2 erl2-1 triple mutant exhibiting more severe phenotypes than those of the mpk3/＋ mpk6/- mutant. The somatic cell layers of the differentiated mutant lobes appeared larger and more disorganized than that of wild-type. In addition, the er-105 erll-2 erl2ol triple mutant has a reduced number of stamens, the majority of which possess completely undifferentiated or under-differentiated anthers. Furthermore, sometimes, the mpk3/＋ mpk6/- mutant anthers do not dehisce, and the er-105 erl1-2 erl2-1 anthers were not observed to dehisce. Therefore, our results indicate that both ER/ERL 1/ERL2 and MPK3/MPK6 play important roles in normal anther lobe formation and anther cell differentiation. The close functional relationship between these genes in other developmental processes and the similarities in anther developmental phenotypes of the two types of mutants reported here further suggest the possibility that these genes might also function in the same pathway to regulate anther cell di展开更多
Genome editing is revolutionizing plant research and crop breeding.Sequence-specific nucleases(SSNs)such as zinc finger nuclease(ZFN)and TAL effector nuclease(TALEN)have been used to create site-specific DNA double-st...Genome editing is revolutionizing plant research and crop breeding.Sequence-specific nucleases(SSNs)such as zinc finger nuclease(ZFN)and TAL effector nuclease(TALEN)have been used to create site-specific DNA double-strand breaks and to achieve precise DNA modifications by promoting homology-directed repair(HDR)(Steinert et al.,2016;Voytas,2013).Later,RNA-guided SSNs such as CRISPR-Cas9,Cas12a,Cas12b,and their variants were applied for genome editing in plants(Li et al.,2013;Nekrasov et alM 2013;Tang et al.,2017;Zhong et al.,2019;Ming et al.,2020;Tang et al.,2019).However,HDR relies on simultaneous delivery of SSNs and DNA donors,which has been challenging in plants(Steinert et al.,2016;Zhang et aL,2019).Another challenge for realizing efficient HDR in plants is that DNA repair favors nonhomologous end joining(NHEJ)pathways over HDR in most cell types(Puchta,2005;Qi et al.,2013).展开更多
Post-translational modification is central to protein stability and to the modulation of protein activity. Various types of protein modification, such as phosphorylation, methylation, acetylation, myristoylation, glyc...Post-translational modification is central to protein stability and to the modulation of protein activity. Various types of protein modification, such as phosphorylation, methylation, acetylation, myristoylation, glycosylation, and ubiquitination, have been reported. Among them, ubiquitination distinguishes itself from others in that most of the ubiquitinated proteins are targeted to the 26S proteasome for degradation. The ubiquitin/26S proteasome system constitutes the major protein degradation pathway in the cell. In recent years, the importance of the ubiquitination machinery in the control of numerous eukaryotic cellular functions has been increasingly appreciated. Increasing number of E3 ubiquitin ligases and their substrates, including a variety of essential cellular regulators have been identified. Studies in the past several years have revealed that the ubiquitination system is important for a broad range of plant developmental processes and responses to abiotic and biotic stresses. This review discusses recent advances in the functional analysis of ubiquitination-associated proteins from plants and pathogens that play important roles in plant-microbe interactions.展开更多
基金Supported in part by the Offices of NP and HEP within the U.S.DOE Office of Sciencethe U.S.NSF+18 种基金the Sloan Foundationthe DFG cluster of excellence‘Origin and Structure of the Universe’of Germany,CNRS/IN2P3STFC and EPSRC of the United KingdomFAPESP CNPq of Brazil,Ministry of Ed.Sci.of the Russian FederationNNSFCCASMoSTMoE of ChinaGA and MSMT of the Czech RepublicFOM and NWO of the NetherlandsDAEDSTCSIR of IndiaPolish Ministry of Sci.Higher Ed.,Korea Research Foundation,Ministry of Sci.,Ed.Sports of the Rep.Of CroatiaRussian Ministry of Sci.and TechRos-Atom of Russia。
文摘Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium,ie.jet-quenching.Previous measurements revealed a strong modification to di-hadron azimuthal correlations in Au+Au collisions with respect to ptp and d+Au collisions.The modification in-creases with the collision centrality,suggesting a path-length or energy density dependence to the je-quenching ef-fect.This paper reports STAR measurements of dihadron azimuthal correlations in mid-central(20%-60%)Au+Au collisions at√^(S)NN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane,Ф_(s)=|Ф_(t)-ψ_(Ep)|.The azimuthal correlation is studied as a function of both the trigger and associated particle pr.The subtractions of the combinatorial background and anisotropic flow,assuming Zero Yield At Minimum(ZYAM),are described.The correlation results are first discussed with subtraction of the even harmonic(elliptic and quadrangu-lar)flow backgrounds.The away-side correlation is strongly modifed,and the modification varies withФ_(s),with a double-peak structure for out-of-plane trigger particles.The near-side ridge(long range pseudo-rapidity△_(η)correla-tion)appears to drop with increasingФ_(s)while the jet-like component remains approximately constant.The correla-tion functions are further studied with the subtraction of odd harmonic triangular flow background arising from fluc-tuations.It is found that the triangular flow,while responsible for the majority of the amplitudes,is not sufficient to explain theφs-dependence of the ridge or the away-side double-peak structure.The dropping ridge withФ_(s)could be attributed to aФ_(s)-dependent lliptie anisotropy;however,the physics mechanism of the ridge remains an open ques-tion.Even with aФ_(s)-dependent elliptic flow,the away-side correlation structure is robust.These results,with exte
基金United Kingdom National Institute for Health ResearchCanadian Institutes of Health Research+4 种基金Presidents FundCanadian Institutes of Health ResearchJohnson & JohnsonBMJthe American Society for Clinical Oncology
文摘大量证据显示随机对照临床试验(randomised controlled trial,RCT)的报告质量不理想。报告不透明,则读者既不能评判试验结果是否真实可靠,也不能从中提取可用于系统综述的信息。最近的方法学分析表明,报告不充分和设计不合理与对治疗效果产生评价偏倚有关。这种系统误差对RCT损害严重,而RCT正是以其能减少或避免偏倚而被视为评价干预措施的金标准。为了提高RCT的报告质量,一个由专家和编辑组成的工作组制定了临床试验报告的统一标准(Consolidated Standards of Reporting Trials,CONSORT)声明。CONSORT声明于1996年首次发表,并于2001年更新。声明由对照检查清单和流程图组成,供作者在报告RCT时使用。许多核心医学期刊和主要国际性编辑组织都已认可CONSORT声明。该声明促进了对RCT的严格评价和解释。2001年,在对CONSORT进行修订时,人们就已经清楚地认识到,解释和说明制定CONSORT声明的原理,有助于研究人员等撰写或评价临床试验报告。一篇CONSORT说明与详述文章于2001年同2001版CONSORT声明一起发表。2007年1月的专家会议之后,对CONSORT声明作了进一步修订并已发表,即"CONSORT2010声明"。这次更新对原版对照检查清单作了文字上的修改,使其更为明晰,并收入了与一些新近才认识到的主题相关的建议,如选择性报告结局产生的偏倚。说明与详述文件旨在加强人们对CONSORT声明的理解、应用和传播,这次也作了大量修订,对每一项新增或更新的清单条目的含义和增改理由进行了解释,提供了优秀的报告实例,还尽可能地提供了相关的经验性研究的参考文献。文中收入了若干流程图实例。"CONSORT2010声明"、其说明与详述文件,以及相关网站(www.consort-statement.org),对于改进随机临床试验报告必将有所裨益。
基金support ongoing meetings was provided by ISPOR-The Professional Society for Health Economics and Outcomes ResearchThe funders had no role in considering the study design or in the collection,analysis,interpretation of data,or writing of the report.Funding for DH and the Delphi Panel exercise was provided by 9363980 Canada Ine+1 种基金the NIHR Applied Research Collaboration(ARC)West Midlandsthe NIHR Health Protection Research Unit(HPRU)Gastrointestinal Infections,and the NIHR HPRU Genomics and Enabling data.
文摘CONSORT声明被广泛用于提高随机对照临床试验的报告质量。Kenneth Schulz等对CONSORT声明的最新版本CONSORT2010作了详细说明,该版本基于新获得的方法学证据和经验的积累对报告指南作了更新。为了鼓励更多的人使用"CONSORT2010声明",本文可从bmj.com免费获取,也将在Lancet,Obstetrics and Gynecology,PLoS Medicine,Annals of Internal Medicine,Open Medicine,Journal of Clinical Epidemiology,BMC Medicine和Trials等杂志发表。
文摘Highly active and low-cost catalysts for electrochemical reactions such as the hydrogen evolution reaction （HER） are crucial for the development of efficient energy conversion and storage technologies. Theoretical simulations have been instrumental in revealing the correlations between the electronic structure of materials and their catalytic activity, and guide the prediction and development of improved catalysts. However, difficulties in accurately engineering the desired atomic sites lead to challenges in making direct comparisons between experi- mental and theoretical results. In MoS2, the Mo-edge has been demonstrated to be active for HER whereas the S-edge is inert. Using a computational descriptor- based approach, we predict that by incorporating transition metal atoms （Fe, Co, Ni, or Cu） the S-edge site should also become HER active. Vertically standing, edge-terminated MoS2 nanofilms provide a well-defined model system for verifying these predictions. The transition metal doped MoS2 nanofilms show an increase in exchange current densities by at least two-fold, in agreement with the theoretical calculations. This work opens up further opportunities for improving electrochemical catalysts by incorporating promoters into particular atomic sites, and for using well-defined systems in order to understand the origin of the promotion effects.
基金the National Science Foundation,grant CBET-1032979the Fluid Interfaces Reactions,Structures and Transport(FIRST)+2 种基金funded by the US Department of Energy,Office of Energy,Office of Basic Energy Sciencessupport from a grant from the US Army Research Laboratory through the Collaborative Research Alliance(CRA)for Multi Scale Multidisciplinary Modeling of Electronic Materials(MSME)the Research Board of the Ghent University(BOF)and BELSPO in the frame of IAP/7/05.
文摘The reactive force-field(ReaxFF)interatomic potential is a powerful computational tool for exploring,developing and optimizing material properties.Methods based on the principles of quantum mechanics(QM),while offering valuable theoretical guidance at the electronic level,are often too computationally intense for simulations that consider the full dynamic evolution of a system.Alternatively,empirical interatomic potentials that are based on classical principles require significantly fewer computational resources,which enables simulations to better describe dynamic processes over longer timeframes and on larger scales.Such methods,however,typically require a predefined connectivity between atoms,precluding simulations that involve reactive events.The ReaxFF method was developed to help bridge this gap.Approaching the gap from the classical side,ReaxFF casts the empirical interatomic potential within a bond-order formalism,thus implicitly describing chemical bonding without expensive QM calculations.This article provides an overview of the development,application,and future directions of the ReaxFF method.
基金supported by Chinese National Science Foundation (NSFC) (No.40875050, 40575037, 40175020)National Key Basic Science Studies Developing Program of "973" (2007CB411506)
文摘A parameterization of soil freezing-thawing physics for use in the land-surface model of the National Center for Atmospheric Research(NCAR) Community Climate Model(CCM3) is developed and evaluated.The new parameterization scheme has improved the representation of physical processes in the existing land surface model.Numerical simulations using CCM3 with improved land-surface processes and with the original land-surface processes are compared against the NCEP reanalysis.It is found that the CCM3 version using the improved land surface model shows significant improvements in simulating precipitation in China during the summer season,the general circulation over East Asia,and wind fields over the Tibet Plateau.For the summer season,the improved model was able to better simulate the Indian summer monsoon components,including the mean northerly wind in the upper troposphere and mean southerly wind in the lower troposphere.
文摘Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multiple alleles of mpk4 and mekkl that exhibit cell death and constitutive defense responses. Bimolecular fluorescence complemen- tation （BiFC） analysis showed that both MPK4 and MEKK1 interact with MKK1 and MKK2, two closely related MAPK kinases, mkkl and mkk2 single mutant plants do not have obvious mutant phenotypes. To test whether MKK1 and MKK2 function redundantly, mkkl mkk2 double mutants were generated. The mkkl mkk2 double mutant plants die at seedling stage and the seedling-lethality phenotype is temperature-dependent. Similar to the mpk4 and mekkl mutants, the mkkl mkk2 double mutant seedlings accumulate high levels of H202, display spontaneous cell death, constitutively express Pathogenesis Related （PR） genes and exhibit pathogen resistance. In addition, activation of MPK4 by fig22 is impaired in the mkkl mkk2 double mutants, suggesting that MKK1 and MKK2 function together with MPK4 and MEKK1 in a MAP kinase cascade to negatively regulate innate immune responses in plants.
文摘Dear Editor, RNA-guided genome editing （RGE） using the Streptococcus pyogenes CRISPR-Cas9 system （Jinek et al., 2012; Cong et al., 2013; Mall et al., 2013b） is emerging as a simple and highly efficient tool for genome editing in many organisms. The Cas9 nuclease can be programmed by dual or single guide RNA （gRNA） to cut target DNA at specific sites,
基金This research is supported by ONR N000141512222,ONR N00014-13-1-0635AFOSR No.FA 9550-14-10332.C.O.acknowledges support from the National Science Foundation Graduate Research Fellowship under grant No.DGF1106401+5 种基金J.P.acknowledges support from the Gordon and Betty Moore Foundation’s EPiQS Initiative through grant No.GBMF4419S.C.acknowledges support by the Alexander von Humboldt-FoundationThis research is supported by ONR N000141512222,ONR N00014-13-1-0635,and AFOSR no.FA 9550-14-10332C.O.acknowledges support from the National Science Foundation Graduate Research Fellowship under grant no.DGF1106401J.P.acknowledges support from the Gordon and Betty Moore Foundation’s EPiQS Initiative through grant no.GBMF4419S.C.acknowledges support by the Alexander von Humboldt-Foundation.
文摘Superconductivity has been the focus of enormous research effort since its discovery more than a century ago.Yet,some features of this unique phenomenon remain poorly understood;prime among these is the connection between superconductivity and chemical/structural properties of materials.To bridge the gap,several machine learning schemes are developed herein to model the critical temperatures(T_(c))of the 12,000+known superconductors available via the SuperCon database.Materials are first divided into two classes based on their T_(c) values,above and below 10 K,and a classification model predicting this label is trained.The model uses coarse-grained features based only on the chemical compositions.It shows strong predictive power,with out-of-sample accuracy of about 92%.Separate regression models are developed to predict the values of T_(c) for cuprate,iron-based,and low-T_(c) compounds.These models also demonstrate good performance,with learned predictors offering potential insights into the mechanisms behind superconductivity in different families of materials.To improve the accuracy and interpretability of these models,new features are incorporated using materials data from the AFLOW Online Repositories.Finally,the classification and regression models are combined into a single-integrated pipeline and employed to search the entire Inorganic Crystallographic Structure Database(ICSD)for potential new superconductors.We identify>30 non-cuprate and non-iron-based oxides as candidate materials.
文摘The Materials Genome Initiative(MGI)advanced a new paradigm for materials discovery and design,namely that the pace of new materials deployment could be accelerated through complementary efforts in theory,computation,and experiment.Along with numerous successes,new challenges are inviting researchers to refocus the efforts and approaches that were originally inspired by the MGI.In May 2017,the National Science Foundation sponsored the workshop“Advancing and Accelerating Materials Innovation Through the Synergistic Interaction among Computation,Experiment,and Theory:Opening New Frontiers”to review accomplishments that emerged from investments in science and infrastructure under the MGI,identify scientific opportunities in this new environment,examine how to effectively utilize new materials innovation infrastructure,and discuss challenges in achieving accelerated materials research through the seamless integration of experiment,computation,and theory.This article summarizes key findings from the workshop and provides perspectives that aim to guide the direction of future materials research and its translation into societal impacts.
文摘We describe a call for an international coordinated effort in rice functional genomics in the form of a project named RICE2020. The mission of the project will be： to determine the function of every gene in the rice genome by the year 2020, to identify functional diversity of alleles for agriculturally useful genes from the primary gene pool of rice, and to apply the findings of functional genomics research to rice genetic improvement.
文摘Mitogen-activated protein kinase （MAPK） and leucine-rich repeat receptor-like kinase （LRR-RLK） signaling pathways have been shown to regulate diverse aspects of plant growth and development. In Arabidopsis, proper anther development relies on intercellular communication to coordinate cell proliferation and differentiation. Two closely related genes encoding MAPKs, MPK3 and MPK6, function redundantly in regulating stomatal patterning. Although the mpk6 mutant has reduced fertility, the function of MPK3 and MPK6 in anther development has not been characterized. Similarly, the ERECTA （ER）, ERECTA-LIKE1 （ERL1） and ERL2 genes encoding LRR-RLKs function together to direct stomatal cell fate specification and the er-105 erll-2 erl2-1 triple mutant is sterile. Because the mpk3 rnpk6 double null mutant is embryo lethal, anther development was characterized in the viable mpk3/＋ mpk6/- and er-105 erll-2 erl2-1 mutants. We found that both mutant anthers usually fail to form one or more of the four anther lobes, with the er-105 erl1-2 erl2-1 triple mutant exhibiting more severe phenotypes than those of the mpk3/＋ mpk6/- mutant. The somatic cell layers of the differentiated mutant lobes appeared larger and more disorganized than that of wild-type. In addition, the er-105 erll-2 erl2ol triple mutant has a reduced number of stamens, the majority of which possess completely undifferentiated or under-differentiated anthers. Furthermore, sometimes, the mpk3/＋ mpk6/- mutant anthers do not dehisce, and the er-105 erl1-2 erl2-1 anthers were not observed to dehisce. Therefore, our results indicate that both ER/ERL 1/ERL2 and MPK3/MPK6 play important roles in normal anther lobe formation and anther cell differentiation. The close functional relationship between these genes in other developmental processes and the similarities in anther developmental phenotypes of the two types of mutants reported here further suggest the possibility that these genes might also function in the same pathway to regulate anther cell di
文摘Genome editing is revolutionizing plant research and crop breeding.Sequence-specific nucleases(SSNs)such as zinc finger nuclease(ZFN)and TAL effector nuclease(TALEN)have been used to create site-specific DNA double-strand breaks and to achieve precise DNA modifications by promoting homology-directed repair(HDR)(Steinert et al.,2016;Voytas,2013).Later,RNA-guided SSNs such as CRISPR-Cas9,Cas12a,Cas12b,and their variants were applied for genome editing in plants(Li et al.,2013;Nekrasov et alM 2013;Tang et al.,2017;Zhong et al.,2019;Ming et al.,2020;Tang et al.,2019).However,HDR relies on simultaneous delivery of SSNs and DNA donors,which has been challenging in plants(Steinert et al.,2016;Zhang et aL,2019).Another challenge for realizing efficient HDR in plants is that DNA repair favors nonhomologous end joining(NHEJ)pathways over HDR in most cell types(Puchta,2005;Qi et al.,2013).
文摘Post-translational modification is central to protein stability and to the modulation of protein activity. Various types of protein modification, such as phosphorylation, methylation, acetylation, myristoylation, glycosylation, and ubiquitination, have been reported. Among them, ubiquitination distinguishes itself from others in that most of the ubiquitinated proteins are targeted to the 26S proteasome for degradation. The ubiquitin/26S proteasome system constitutes the major protein degradation pathway in the cell. In recent years, the importance of the ubiquitination machinery in the control of numerous eukaryotic cellular functions has been increasingly appreciated. Increasing number of E3 ubiquitin ligases and their substrates, including a variety of essential cellular regulators have been identified. Studies in the past several years have revealed that the ubiquitination system is important for a broad range of plant developmental processes and responses to abiotic and biotic stresses. This review discusses recent advances in the functional analysis of ubiquitination-associated proteins from plants and pathogens that play important roles in plant-microbe interactions.
