Systematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO_(2) reduction to solar f...Systematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO_(2) reduction to solar fuels.A surface-modified Ag@Ru-P25 photocatalyst with H_(2)O_(2) treatment was designed in this study to convert CO_(2) and H_(2)O vapor into highly selective CH4.Ru doping followed by Ag nanoparticles(NPs)cocatalyst deposition on P25(TiO_(2))enhances visible light absorption and charge separation,whereas H_(2)O_(2) treatment modifies the surface of the photocatalyst with hydroxyl(–OH)groups and promotes CO_(2) adsorption.High-resonance transmission electron microscopy,X-ray photoelectron spectroscopy,X-ray absorption near-edge structure,and extended X-ray absorption fine structure techniques were used to analyze the surface and chemical composition of the photocatalyst,while thermogravimetric analysis,CO_(2) adsorption isotherm,and temperature programmed desorption study were performed to examine the significance of H_(2)O_(2) treatment in increasing CO_(2) reduction activity.The optimized Ag1.0@Ru1.0-P25 photocatalyst performed excellent CO_(2) reduction activity into CO,CH4,and C2H6 with a~95%selectivity of CH4,where the activity was~135 times higher than that of pristine TiO_(2)(P25).For the first time,this work explored the effect of H_(2)O_(2) treatment on the photocatalyst that dramatically increases CO_(2) reduction activity.展开更多
Defects in materials significantly alter their electronic and structural properties,which affect the per-formance of electronic devices,structural alloys,and functional materials.However,calculating all the possible d...Defects in materials significantly alter their electronic and structural properties,which affect the per-formance of electronic devices,structural alloys,and functional materials.However,calculating all the possible defects in complex materials with conventional Density Functional Theory(DFT)can be compu-tationally prohibitive.To enhance the efficiency of these calculations,we interfaced Density Functional Tight Binding(DFTB)with the Clusters Approach to Statistical Mechanics(CASM)software package for the first time.Using SiC and ZnO as representative examples,we show that DFTB gives accurate results and can be used as an efficient computational approach for calculating and pre-screening formation ener-gies/convex hulls.Our DFTB+CASM implementation allows for an efficient exploration(up to an order of magnitude faster than DFT)of formation energies and convex hulls,which researchers can use to probe other complex systems.展开更多
Viral structural proteins form the capsid or protein shell of mature viral particles and are the first viral proteins exposed to the host immune system during infection. Vertebrates including humans control viral infe...Viral structural proteins form the capsid or protein shell of mature viral particles and are the first viral proteins exposed to the host immune system during infection. Vertebrates including humans control viral infections by launching potent adaptive immune responses to specifically target viral structural proteins with B and T lymphocytes. However, it remains unclear whether plants direct a natural immune response against viral structural proteins.展开更多
Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health.Despite global efforts to mitigate legacy pollutants,the continuous introduction of new su...Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health.Despite global efforts to mitigate legacy pollutants,the continuous introduction of new substances remains a major threat to both people and the planet.In response,global initiatives are focusing on risk assessment and regulation of emerging contaminants,as demonstrated by the ongoing efforts to establish the UN’s Intergovernmental Science-Policy Panel on Chemicals,Waste,and Pollution Prevention.This review identifies the sources and impacts of emerging contaminants on planetary health,emphasizing the importance of adopting a One Health approach.Strategies for monitoring and addressing these pollutants are discussed,underscoring the need for robust and socially equitable environmental policies at both regional and international levels.Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.展开更多
Ethylene signaling is a complex pathway that has been intensively analyzed partly due to its importance to the manifestation of horticultural phenomena, including fruit ripening and tissue senescence. In order to furt...Ethylene signaling is a complex pathway that has been intensively analyzed partly due to its importance to the manifestation of horticultural phenomena, including fruit ripening and tissue senescence. In order to further our un- derstanding of how this pathway is regulated, a screen for Arabidopsis mutants with increased ethylene response was conducted. From this, a mutant was identified as having a dark-grown hypocotyl that is indistinguishable from Col-0 wt in the presence of the ethylene perception inhibitor AgNO3, yet has extreme responsiveness to even low levels of ethylene. Map-based cloning of the mutation revealed a T-DNA insertion in the coding sequence of the receptor-like kinase FERONIA, which is required for normal pollen tube reception and cell elongation in a currently unknown capacity. In contrast to a previous report, analysis of our feronia knockout mutant shows it also has altered responsiveness to brassinosteroids, with etiolated fer-2 seedlings being partially brassinosteroid insensitive with regard to promotion of hypocotyl elonga- tion. Our results indicate that FERONIA-dependent brassinosteroid response serves to antagonize the effect of ethylene on hypocotyl growth of etiolated seedlings, with loss of proper brassinosteroid signaling disrupting this balance and leading to a greater impact of ethylene on hypocotyl shortening.展开更多
Global land cover(LC)maps have been widely employed as the base layer for a number of applications including climate change,food security,water quality,biodiversity,change detection,and environmental planning.Due to t...Global land cover(LC)maps have been widely employed as the base layer for a number of applications including climate change,food security,water quality,biodiversity,change detection,and environmental planning.Due to the importance of LC,there is a pressing need to increase the temporal and spatial resolution of global LC maps.A recent advance in this direction has been the GlobeLand30 dataset derived from Landsat imagery,which has been developed by the National Geomatics Center of China(NGCC).Although overall accuracy is greater than 80%,the NGCC would like help in assessing the accuracy of the product in different regions of the world.To assist in this process,this study compares the GlobeLand30 product with existing public and online datasets,that is,CORINE,Urban Atlas(UA),OpenStreetMap,and ATKIS for Germany in order to assess overall and per class agreement.The results of the analysis reveal high agreement of up to 92%between these datasets and GlobeLand30 but that large disagreements for certain classes are evident,in particular wetlands.However,overall,GlobeLand30 is shown to be a useful product for characterizing LC in Germany,and paves the way for further regional and national validation efforts.展开更多
Silver nanowires (AgNWs) hold great promise for applications in wearable electronics, flexible solar cells, chemical and biological sensors, photonic/plasmonic circuits, and scanning probe microscopy (SPM) due to thei...Silver nanowires (AgNWs) hold great promise for applications in wearable electronics, flexible solar cells, chemical and biological sensors, photonic/plasmonic circuits, and scanning probe microscopy (SPM) due to their unique plasmonic, mechanical, and electronic properties. However, the lifetime, reliability, and operating conditions of AgNW-based devices are significantly restricted by their poor chemical stability, limiting their commercial potentials. Therefore, it is crucial to create a reliable oxidation barrier on AgNWs that provides long-term chemical stability to various optical, electrical, and mechanical devices while maintaining their high performance. Here we report a room-temperature solution-phase approach to grow an ultra-thin, epitaxial gold coating on AgNWs to effectively shield the Ag surface from environmental oxidation. The Ag@Au core-shell nanowires (Ag@Au NWs) remain stable in air for over six months, under elevated temperature and humidity (80 °C and 100% humidity) for twelve weeks, in physiological buffer solutions for three weeks, and can survive overnight treatment of an oxidative solution (2% H2O2). The Ag@Au core-shell NWs demonstrated comparable performance as pristine AgNWs in various electronic, optical, and mechanical devices, such as transparent mesh electrodes, surface-enhanced Raman spectroscopy (SERS) substrates, plasmonic waveguides, plasmonic nanofocusing probes, and high-aspect-ratio, high-resolution atomic force microscopy (AFM) probes. These Au@Ag core-shell NWs offer a universal solution towards chemically-stable AgNW-based devices without compromising material property or device performance.展开更多
The past decade has witnessed an acceleration of autonomous vehicle research and development,with technological advances contributed by academia,government,and the industrial and consumer sectors.These advancements ho...The past decade has witnessed an acceleration of autonomous vehicle research and development,with technological advances contributed by academia,government,and the industrial and consumer sectors.These advancements hold the potential to improve society by enhancing transportation safety and throughput,where decreased congestion saves time and reduces vehicle emissions.Two of the key technologies to enable vehicle infrastructure interaction,advanced traffic management,and automated vehicles are automated roadway mapping and reliable vehicle state estimation.In this paper,we present an overview and new methods for the problems automated roadway mapping plus a discussion of the extension of these methods to the problem of vehicle state estimation.Results from the application of these methods to feature mapping and state estimation are presented.展开更多
Tip-enhanced Raman spectroscopy(TERS)imaging is a super-resolution imaging technique that features the merits of both surface-enhanced Raman spectroscopy(SERS)and scanning probe microscopy(SPM),such as the high chemic...Tip-enhanced Raman spectroscopy(TERS)imaging is a super-resolution imaging technique that features the merits of both surface-enhanced Raman spectroscopy(SERS)and scanning probe microscopy(SPM),such as the high chemical sensitivity from the former and the nanoscale spatial resolution from the latter.These advantages make TERS an essential nanospectroscopic characterization technique for chemical analysis,materials science,bio-sensing,etc.TERS probes,the most critical factor determining the TERS imaging quality,are expected to provide a highly confined electromagnetic hotspot with a minimized scattering background for the generation of Raman signals with high spatial resolution.After two decades of development,numerous probe design concepts have been proposed and demonstrated.This review provides a comprehensive overview of the state-of-the-art TERS probe designs,from the working mechanism to the practical performance.We start with reviewing the recent development of TERS configurations and the corresponding working mechanisms,including the SPM platforms,optical excitation/collection techniques,and probe preparation methods.We then review the emerging novel TERS probe designs,including the remote-excitation probes,the waveguide-based nanofocusing probes,the metal-coated nanofocusing probes,the nanowire-assisted selective-coupling probes,and the tapered metal-insulator-metal probes.Our discussion focuses on a few critical aspects,including the surface-plasmon-polariton(SPP)hotspot excitation technique,conversion efficiency,working frequency,and controllability.In the end,we review the latest TERS applications and give a perspective on the future of TERS.展开更多
Early efforts to classify Mortierellaceae were based on macro-and micromorphology,but sequencing and phylogenetic studies with ribosomal DNA(rDNA)markers have demonstrated conflicting taxonomic groupings and polyphyle...Early efforts to classify Mortierellaceae were based on macro-and micromorphology,but sequencing and phylogenetic studies with ribosomal DNA(rDNA)markers have demonstrated conflicting taxonomic groupings and polyphyletic genera.Although some taxonomic confusion in the family has been clarified,rDNA data alone is unable to resolve higher level phylogenetic relationships within Mortierellaceae.In this study,we applied two parallel approaches to resolve the Mortierel-laceae phylogeny:low coverage genome(LCG)sequencing and high-throughput,multiplexed targeted amplicon sequenc-ing to generate sequence data for multi-gene phylogenetics.We then combined our datasets to provide a well-supported genome-based phylogeny having broad sampling depth from the amplicon dataset.Resolving the Mortierellaceae phylogeny into monophyletic genera resulted in 13 genera,7 of which are newly proposed.Low-coverage genome sequencing proved to be a relatively cost-effective means of generating a high-confidence phylogeny.The multi-gene phylogenetics approach enabled much greater sampling depth and breadth than the LCG approach,but has limitations too.We present this work to resolve some of the taxonomic confusion and provide a genus-level framework to empower future studies on Mortierellaceae diversity and evolution.展开更多
Dear Editor,Approximately 25%of acute myeloid leukemia(AML)carries FLT3-ITD(internal tandem duplication)oncogenic mutations.Although FLT3 kinase inhibitors have already been successfully used in the clinic for treatin...Dear Editor,Approximately 25%of acute myeloid leukemia(AML)carries FLT3-ITD(internal tandem duplication)oncogenic mutations.Although FLT3 kinase inhibitors have already been successfully used in the clinic for treating FLT3-ITD-positive AML,acquired drug resistance is observed after the prolonged treatment.Therefore,seeking a new therapeutic strategy is still imperative for FLT3-ITD-positive AML.展开更多
In this paper,we discuss the previous advances,current challenges,and future opportunities for the research of catalytic reduction of water pollutants.We present five case studies on the development of palladium-based...In this paper,we discuss the previous advances,current challenges,and future opportunities for the research of catalytic reduction of water pollutants.We present five case studies on the development of palladium-based catalysts for nitrate,chlorate,and perchlorate reduction with hydrogen gas under ambient conditions.We emphasize the realization of new functionalities through the screening and design of catalytic metal sites,including(i)platinum group metal(PGM)nanoparticles,(ii)the secondary metals for improving the reaction rate and product selectivity of nitrate reduction,(iii)oxygen-atom-transfer metal oxides for chlorate and perchlorate reduction,and(iv)ligand-enhanced coordination complexes for substantial activity enhancement.We also highlight the facile catalyst preparation approach that brought significant convenience to catalyst optimization.Based on our own studies,we then discuss directions of the catalyst research effort that are not immediately necessary or desirable,including(1)systematic study on the downstream aspects of under-developed catalysts,(2)random integration with hot concepts without a clear rationale,and(3)excessive and decorative experiments.We further address some general concerns regarding using H2 and PGMs in the catalytic system.Finally,we recommend future catalyst development in both“fundamental”and“applied”aspects.The purpose of this perspective is to remove major misconceptions about reductive catalysis research and bring back significant innovations for both scientific advancements and engineering applications to benefit environmental protection.展开更多
Background:Cryo-electron microscopy(Cryo-EM)and tomography(Cryo-ET)have emerged as important imaging techniques for studying structures of macromolecular complexes.In 3D reconstruction of large macromolecular complexe...Background:Cryo-electron microscopy(Cryo-EM)and tomography(Cryo-ET)have emerged as important imaging techniques for studying structures of macromolecular complexes.In 3D reconstruction of large macromolecular complexes,many 2D projection images of macromolecular complex particles are usually acquired with low signal-tonoise ratio.Therefore,it is meaningful to select multiple images containing the same structure with identical orientation.The selected images are averaged to produce a higher-quality representation of the underlying structure with improved resolution.Existing approaches of selecting such images have limited accuracy and speed.Methods:We propose a simulated annealing-based algorithm(SA)to pick the homogeneous image set with best average.Its performance is compared with two baseline methods based on both 2D and 3D datasets.When tested on simulated and experimental 3D Cryo-ET images of Ribosome complex,SA sometimes stopped at a local optimal solution.Restarting is applied to settle this difficulty and significantly improved the performance of SA on 3D datasets.Results:Experimented on simulated and experimental 2D Cryo-EM images of Ribosome complex datasets respectively with SNR=10 and SNR=0.5,our method achieved better accuracy in terms of F-measure,resolution score,and time cost than two baseline methods.Additionally,SA shows its superiority when the proportion of homogeneous images decreases.Conclusions:SA is introduced for homogeneous image selection to realize higher accuracy with faster processing speed.Experiments on both simulated and real 2D Cryo-EM and 3D Cryo-ET images demonstrated that SA achieved expressively better performance.This approach serves as an important step for improving the resolution of structural recovery of macromolecular complexes captured by Cryo-EM and Cryo-ET.展开更多
Carbon （C） and nitrogen （N） are two essential nutrients affecting plant growth and development. Plants are non-motile organisms and have evolved highly sophisticated and complex sensing and signaling mechanisms to...Carbon （C） and nitrogen （N） are two essential nutrients affecting plant growth and development. Plants are non-motile organisms and have evolved highly sophisticated and complex sensing and signaling mechanisms to respond to the dynamic changes of C and N nutrients in their surroundings. C and N metabolism are tightly coordinated to maintain intraceilular C/N homeostasis. However, the regulatory mechanism underlying C/N coordination and balancing in plants remains to be elucidated. It has been suggested that C and N metabolism are modulated by the interaction of C signaling with N signaling or by C/N ratio signaling. This review focuses on cell signaling studies that provide insight into the regulation mechanism of C/N balancing in plants.展开更多
Determination of an appropriate location for monitoring soil water content (SWC) is a keyfactor in efficient use of water in precision agriculture, however, the main challenge is thedynamic movement of water and root ...Determination of an appropriate location for monitoring soil water content (SWC) is a keyfactor in efficient use of water in precision agriculture, however, the main challenge is thedynamic movement of water and root development in the soil profile. The objective of thisstudy was investigating how SWC distribution in a loam soil profile at two growth stages ofmaize may impact the suitable location for SWC monitoring in a drip-tape irrigation system.A new concept, Average Moisture Representative Surface (AMRS) was proposed to determine the surface of the soil profile, which represent the average soil moisture of the wettedvolume. SWC samples were taken during two irrigation intervals (48~52 days after planting(DAP) and 68~73 DAP) and root growth pattern was studied through root length density (RLD)at 50 and 100 DAP. The results revealed that a non-uniform wetting pattern after irrigationlimits the appropriate locations for SWC monitoring to point measurements and with time,SWC depletion resulted in enlarging AMRS. At the end of growing season, an increase of rootgrowth around the drippers increased the variation of root water uptake in different soil layers, and thus optimal place for soil sensors was limited to the upper layers, where the maximum root water uptake occurred. Overall, it is recommended to install soil sensors, such astensiometers and TDRs at a horizontal distance of 5~20 cm from the crop and a depth of10~20 cm from the soil surface while drip-tape is aligned close to the maize row.展开更多
基金supported by the Ministry of Science and ICT in Korea(2021R1A2C2009459)X-ray absorption spectra were obtained from Pohang Accelerator Laboratory(PAL)10C beamlinesupported by the US Department of Energy,Office of Science,Office of Advanced Scientific Computing Research,and Scientific Discovery through Advanced Computing(SciDAC)program under Award Number DE-SC0022209.
文摘Systematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO_(2) reduction to solar fuels.A surface-modified Ag@Ru-P25 photocatalyst with H_(2)O_(2) treatment was designed in this study to convert CO_(2) and H_(2)O vapor into highly selective CH4.Ru doping followed by Ag nanoparticles(NPs)cocatalyst deposition on P25(TiO_(2))enhances visible light absorption and charge separation,whereas H_(2)O_(2) treatment modifies the surface of the photocatalyst with hydroxyl(–OH)groups and promotes CO_(2) adsorption.High-resonance transmission electron microscopy,X-ray photoelectron spectroscopy,X-ray absorption near-edge structure,and extended X-ray absorption fine structure techniques were used to analyze the surface and chemical composition of the photocatalyst,while thermogravimetric analysis,CO_(2) adsorption isotherm,and temperature programmed desorption study were performed to examine the significance of H_(2)O_(2) treatment in increasing CO_(2) reduction activity.The optimized Ag1.0@Ru1.0-P25 photocatalyst performed excellent CO_(2) reduction activity into CO,CH4,and C2H6 with a~95%selectivity of CH4,where the activity was~135 times higher than that of pristine TiO_(2)(P25).For the first time,this work explored the effect of H_(2)O_(2) treatment on the photocatalyst that dramatically increases CO_(2) reduction activity.
基金supported by the U.S.Department of Energy,Na-tional Energy Technology Laboratory(NETL),under Award No.DE-FE0030582.
文摘Defects in materials significantly alter their electronic and structural properties,which affect the per-formance of electronic devices,structural alloys,and functional materials.However,calculating all the possible defects in complex materials with conventional Density Functional Theory(DFT)can be compu-tationally prohibitive.To enhance the efficiency of these calculations,we interfaced Density Functional Tight Binding(DFTB)with the Clusters Approach to Statistical Mechanics(CASM)software package for the first time.Using SiC and ZnO as representative examples,we show that DFTB gives accurate results and can be used as an efficient computational approach for calculating and pre-screening formation ener-gies/convex hulls.Our DFTB+CASM implementation allows for an efficient exploration(up to an order of magnitude faster than DFT)of formation energies and convex hulls,which researchers can use to probe other complex systems.
文摘Viral structural proteins form the capsid or protein shell of mature viral particles and are the first viral proteins exposed to the host immune system during infection. Vertebrates including humans control viral infections by launching potent adaptive immune responses to specifically target viral structural proteins with B and T lymphocytes. However, it remains unclear whether plants direct a natural immune response against viral structural proteins.
基金funded by the National Key Research and Development Program of China(2020YFC1807000)the Strategic Priority Research Program of the Chinese Academy of Sciences(no.XDA28030501)+9 种基金the National Natural Science Foundation of China(41991333,41977137,42090060)the International Atomic Energy Agency Research Project(D15022)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2011225[Fang Wang],Y201859[H.Wang],2013201[J.Su],2021309[Y.Song],Y2022084[M.Ye])Chinese Academy of Sciences President’s International Fellowship Initiative(2020DC0005,2022DC0001,2024DC0009)the Institute of Soil Science,Chinese Academy of Sciences(ISSAS2419)the Research Group Linkage project from Alexander von Humboldt foundation,the Center for Health Impacts of Agriculture(CHIA)of Michigan State University,and the URI STEEP Superfund Center(grant#P42ES027706)Fang Wang was partly supported by the fellowship of Alexander von Humboldt for experienced researchers,and Shennong Young Talents of the Ministry of Agriculture and Rural Affairs,China(SNYCQN006-2022)J.P.and T.R.S.were supported by the Canada Research Chair program.B.W.B.was supported by a Royal Society of New Zealand Catalyst International Leaders fellowship.K.K.B.was supported by Innovation Fund Denmark and the European Commission Horizon 2020 financed under the ERA-NET Aquatic Pollutants Joint Transnational Call(REWA,GA no.869178)S.A.H.was partly supported by a grant from the National Institute of Environmental Health Sciences,National Institutes of Health grant number P42ES04911-29(Project 4)T.R.S.thanks CESAM by FCT/MCTES(UIDP/50017/2020+UIDB/50017/2020+LA/P/0094/2020)。
文摘Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health.Despite global efforts to mitigate legacy pollutants,the continuous introduction of new substances remains a major threat to both people and the planet.In response,global initiatives are focusing on risk assessment and regulation of emerging contaminants,as demonstrated by the ongoing efforts to establish the UN’s Intergovernmental Science-Policy Panel on Chemicals,Waste,and Pollution Prevention.This review identifies the sources and impacts of emerging contaminants on planetary health,emphasizing the importance of adopting a One Health approach.Strategies for monitoring and addressing these pollutants are discussed,underscoring the need for robust and socially equitable environmental policies at both regional and international levels.Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.
文摘Ethylene signaling is a complex pathway that has been intensively analyzed partly due to its importance to the manifestation of horticultural phenomena, including fruit ripening and tissue senescence. In order to further our un- derstanding of how this pathway is regulated, a screen for Arabidopsis mutants with increased ethylene response was conducted. From this, a mutant was identified as having a dark-grown hypocotyl that is indistinguishable from Col-0 wt in the presence of the ethylene perception inhibitor AgNO3, yet has extreme responsiveness to even low levels of ethylene. Map-based cloning of the mutation revealed a T-DNA insertion in the coding sequence of the receptor-like kinase FERONIA, which is required for normal pollen tube reception and cell elongation in a currently unknown capacity. In contrast to a previous report, analysis of our feronia knockout mutant shows it also has altered responsiveness to brassinosteroids, with etiolated fer-2 seedlings being partially brassinosteroid insensitive with regard to promotion of hypocotyl elonga- tion. Our results indicate that FERONIA-dependent brassinosteroid response serves to antagonize the effect of ethylene on hypocotyl growth of etiolated seedlings, with loss of proper brassinosteroid signaling disrupting this balance and leading to a greater impact of ethylene on hypocotyl shortening.
基金The authors would also like to acknowledge the support and contribution of COST Action TD1202‘Mapping and the Citizen Sensor’as well as COST Action IC1203‘European Network Exploring Research into Geospatial Information Crowdsourcing’(ENERGIC).
文摘Global land cover(LC)maps have been widely employed as the base layer for a number of applications including climate change,food security,water quality,biodiversity,change detection,and environmental planning.Due to the importance of LC,there is a pressing need to increase the temporal and spatial resolution of global LC maps.A recent advance in this direction has been the GlobeLand30 dataset derived from Landsat imagery,which has been developed by the National Geomatics Center of China(NGCC).Although overall accuracy is greater than 80%,the NGCC would like help in assessing the accuracy of the product in different regions of the world.To assist in this process,this study compares the GlobeLand30 product with existing public and online datasets,that is,CORINE,Urban Atlas(UA),OpenStreetMap,and ATKIS for Germany in order to assess overall and per class agreement.The results of the analysis reveal high agreement of up to 92%between these datasets and GlobeLand30 but that large disagreements for certain classes are evident,in particular wetlands.However,overall,GlobeLand30 is shown to be a useful product for characterizing LC in Germany,and paves the way for further regional and national validation efforts.
基金This material is based upon work supported by the National Science Foundation under gant No.CHE-1654794.The authors acknowledge Prof.Yadong Yin from the Department of Chemistry,UC Riverside for helpful discussion.
文摘Silver nanowires (AgNWs) hold great promise for applications in wearable electronics, flexible solar cells, chemical and biological sensors, photonic/plasmonic circuits, and scanning probe microscopy (SPM) due to their unique plasmonic, mechanical, and electronic properties. However, the lifetime, reliability, and operating conditions of AgNW-based devices are significantly restricted by their poor chemical stability, limiting their commercial potentials. Therefore, it is crucial to create a reliable oxidation barrier on AgNWs that provides long-term chemical stability to various optical, electrical, and mechanical devices while maintaining their high performance. Here we report a room-temperature solution-phase approach to grow an ultra-thin, epitaxial gold coating on AgNWs to effectively shield the Ag surface from environmental oxidation. The Ag@Au core-shell nanowires (Ag@Au NWs) remain stable in air for over six months, under elevated temperature and humidity (80 °C and 100% humidity) for twelve weeks, in physiological buffer solutions for three weeks, and can survive overnight treatment of an oxidative solution (2% H2O2). The Ag@Au core-shell NWs demonstrated comparable performance as pristine AgNWs in various electronic, optical, and mechanical devices, such as transparent mesh electrodes, surface-enhanced Raman spectroscopy (SERS) substrates, plasmonic waveguides, plasmonic nanofocusing probes, and high-aspect-ratio, high-resolution atomic force microscopy (AFM) probes. These Au@Ag core-shell NWs offer a universal solution towards chemically-stable AgNW-based devices without compromising material property or device performance.
基金supported in part by the US Department of Transportation Federal Highway Administration[grant number DTFH61-09-C-00018]and[grant number DTFH61-06-D-00006]California Department of Transportation[grant number 65A0261].
文摘The past decade has witnessed an acceleration of autonomous vehicle research and development,with technological advances contributed by academia,government,and the industrial and consumer sectors.These advancements hold the potential to improve society by enhancing transportation safety and throughput,where decreased congestion saves time and reduces vehicle emissions.Two of the key technologies to enable vehicle infrastructure interaction,advanced traffic management,and automated vehicles are automated roadway mapping and reliable vehicle state estimation.In this paper,we present an overview and new methods for the problems automated roadway mapping plus a discussion of the extension of these methods to the problem of vehicle state estimation.Results from the application of these methods to feature mapping and state estimation are presented.
基金supported by the National Science Foundation(Nos.1654746 and 1810453).
文摘Tip-enhanced Raman spectroscopy(TERS)imaging is a super-resolution imaging technique that features the merits of both surface-enhanced Raman spectroscopy(SERS)and scanning probe microscopy(SPM),such as the high chemical sensitivity from the former and the nanoscale spatial resolution from the latter.These advantages make TERS an essential nanospectroscopic characterization technique for chemical analysis,materials science,bio-sensing,etc.TERS probes,the most critical factor determining the TERS imaging quality,are expected to provide a highly confined electromagnetic hotspot with a minimized scattering background for the generation of Raman signals with high spatial resolution.After two decades of development,numerous probe design concepts have been proposed and demonstrated.This review provides a comprehensive overview of the state-of-the-art TERS probe designs,from the working mechanism to the practical performance.We start with reviewing the recent development of TERS configurations and the corresponding working mechanisms,including the SPM platforms,optical excitation/collection techniques,and probe preparation methods.We then review the emerging novel TERS probe designs,including the remote-excitation probes,the waveguide-based nanofocusing probes,the metal-coated nanofocusing probes,the nanowire-assisted selective-coupling probes,and the tapered metal-insulator-metal probes.Our discussion focuses on a few critical aspects,including the surface-plasmon-polariton(SPP)hotspot excitation technique,conversion efficiency,working frequency,and controllability.In the end,we review the latest TERS applications and give a perspective on the future of TERS.
基金US National Science Foundation(NSF)DEB 1737898(GB and NVP),Michigan State University AgBioResearch NIFA project MICL02416(GB),NSF STC BEACON Cooperative Agreement DBI-093954(GB&NVP)US National Science Foundation(The Zygomycetes Genealogy of Life)DEB1354802 and DEB1441677(JS)+1 种基金JGI-the work conducted by the U.S.Department of Energy Joint Genome Institute,a DOE Office of Science User Facility,is supported by the Office of Science of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231Data analyses were performed on the High-Performance Computing Cluster at the University of California-Riverside in the Institute of Integrative Genome Biology supported by NSF DBI-1429826 and NIH S10-OD016290(JS).
文摘Early efforts to classify Mortierellaceae were based on macro-and micromorphology,but sequencing and phylogenetic studies with ribosomal DNA(rDNA)markers have demonstrated conflicting taxonomic groupings and polyphyletic genera.Although some taxonomic confusion in the family has been clarified,rDNA data alone is unable to resolve higher level phylogenetic relationships within Mortierellaceae.In this study,we applied two parallel approaches to resolve the Mortierel-laceae phylogeny:low coverage genome(LCG)sequencing and high-throughput,multiplexed targeted amplicon sequenc-ing to generate sequence data for multi-gene phylogenetics.We then combined our datasets to provide a well-supported genome-based phylogeny having broad sampling depth from the amplicon dataset.Resolving the Mortierellaceae phylogeny into monophyletic genera resulted in 13 genera,7 of which are newly proposed.Low-coverage genome sequencing proved to be a relatively cost-effective means of generating a high-confidence phylogeny.The multi-gene phylogenetics approach enabled much greater sampling depth and breadth than the LCG approach,but has limitations too.We present this work to resolve some of the taxonomic confusion and provide a genus-level framework to empower future studies on Mortierellaceae diversity and evolution.
基金supported by the National Natural Science Foundation of China(Grant Nos.81903650,81803366,81673469,81773777)the Natural Science Foundation of Anhui Province(Grant Nos.2008085MH274,1808085MH268)+4 种基金the China Postdoctoral Science Foundation(Grant No.2019M652057)the Postdoctoral Science Foundation of Anhui Province(Grant No.2019B300)the Frontier Science Key Research Program of CAS(Grant No.QYZDB-SSW-SLH037)the Collaborative Innovation Program of Hefei Science Center,CAS(Grant No.2019HSC-CIP011)the CASHIPS Director’s Fund(Grant Nos.BJPY2019A03,YZJJZX202011).
文摘Dear Editor,Approximately 25%of acute myeloid leukemia(AML)carries FLT3-ITD(internal tandem duplication)oncogenic mutations.Although FLT3 kinase inhibitors have already been successfully used in the clinic for treating FLT3-ITD-positive AML,acquired drug resistance is observed after the prolonged treatment.Therefore,seeking a new therapeutic strategy is still imperative for FLT3-ITD-positive AML.
基金Financial support was provided by the U.S. National Science Foundation (CBET-1932942).
文摘In this paper,we discuss the previous advances,current challenges,and future opportunities for the research of catalytic reduction of water pollutants.We present five case studies on the development of palladium-based catalysts for nitrate,chlorate,and perchlorate reduction with hydrogen gas under ambient conditions.We emphasize the realization of new functionalities through the screening and design of catalytic metal sites,including(i)platinum group metal(PGM)nanoparticles,(ii)the secondary metals for improving the reaction rate and product selectivity of nitrate reduction,(iii)oxygen-atom-transfer metal oxides for chlorate and perchlorate reduction,and(iv)ligand-enhanced coordination complexes for substantial activity enhancement.We also highlight the facile catalyst preparation approach that brought significant convenience to catalyst optimization.Based on our own studies,we then discuss directions of the catalyst research effort that are not immediately necessary or desirable,including(1)systematic study on the downstream aspects of under-developed catalysts,(2)random integration with hot concepts without a clear rationale,and(3)excessive and decorative experiments.We further address some general concerns regarding using H2 and PGMs in the catalytic system.Finally,we recommend future catalyst development in both“fundamental”and“applied”aspects.The purpose of this perspective is to remove major misconceptions about reductive catalysis research and bring back significant innovations for both scientific advancements and engineering applications to benefit environmental protection.
基金We thank Dr.Ming Sun for suggestions and Mr.Shan Zhou for initial exploratory studies.We thank Ms.Xindi Wu for helping with manuscript editingThis work was supported in part by U.S.National Institutes of Health(NIH)grant(P4l GM103712)+1 种基金MX acknowledges support from Samuel and Emma Winters FoundationXZ was supported by a fellowship from Carnegie Mellon University's Center for Machine Learning and Health.RJ is a RONG professor at the Institute for Data Science,Tsinghua University.
文摘Background:Cryo-electron microscopy(Cryo-EM)and tomography(Cryo-ET)have emerged as important imaging techniques for studying structures of macromolecular complexes.In 3D reconstruction of large macromolecular complexes,many 2D projection images of macromolecular complex particles are usually acquired with low signal-tonoise ratio.Therefore,it is meaningful to select multiple images containing the same structure with identical orientation.The selected images are averaged to produce a higher-quality representation of the underlying structure with improved resolution.Existing approaches of selecting such images have limited accuracy and speed.Methods:We propose a simulated annealing-based algorithm(SA)to pick the homogeneous image set with best average.Its performance is compared with two baseline methods based on both 2D and 3D datasets.When tested on simulated and experimental 3D Cryo-ET images of Ribosome complex,SA sometimes stopped at a local optimal solution.Restarting is applied to settle this difficulty and significantly improved the performance of SA on 3D datasets.Results:Experimented on simulated and experimental 2D Cryo-EM images of Ribosome complex datasets respectively with SNR=10 and SNR=0.5,our method achieved better accuracy in terms of F-measure,resolution score,and time cost than two baseline methods.Additionally,SA shows its superiority when the proportion of homogeneous images decreases.Conclusions:SA is introduced for homogeneous image selection to realize higher accuracy with faster processing speed.Experiments on both simulated and real 2D Cryo-EM and 3D Cryo-ET images demonstrated that SA achieved expressively better performance.This approach serves as an important step for improving the resolution of structural recovery of macromolecular complexes captured by Cryo-EM and Cryo-ET.
文摘Carbon （C） and nitrogen （N） are two essential nutrients affecting plant growth and development. Plants are non-motile organisms and have evolved highly sophisticated and complex sensing and signaling mechanisms to respond to the dynamic changes of C and N nutrients in their surroundings. C and N metabolism are tightly coordinated to maintain intraceilular C/N homeostasis. However, the regulatory mechanism underlying C/N coordination and balancing in plants remains to be elucidated. It has been suggested that C and N metabolism are modulated by the interaction of C signaling with N signaling or by C/N ratio signaling. This review focuses on cell signaling studies that provide insight into the regulation mechanism of C/N balancing in plants.
基金Funding for this study was provided by Isfahan University of Technology and Iran National Science Foundation(INSF)(project No.97010962).
文摘Determination of an appropriate location for monitoring soil water content (SWC) is a keyfactor in efficient use of water in precision agriculture, however, the main challenge is thedynamic movement of water and root development in the soil profile. The objective of thisstudy was investigating how SWC distribution in a loam soil profile at two growth stages ofmaize may impact the suitable location for SWC monitoring in a drip-tape irrigation system.A new concept, Average Moisture Representative Surface (AMRS) was proposed to determine the surface of the soil profile, which represent the average soil moisture of the wettedvolume. SWC samples were taken during two irrigation intervals (48~52 days after planting(DAP) and 68~73 DAP) and root growth pattern was studied through root length density (RLD)at 50 and 100 DAP. The results revealed that a non-uniform wetting pattern after irrigationlimits the appropriate locations for SWC monitoring to point measurements and with time,SWC depletion resulted in enlarging AMRS. At the end of growing season, an increase of rootgrowth around the drippers increased the variation of root water uptake in different soil layers, and thus optimal place for soil sensors was limited to the upper layers, where the maximum root water uptake occurred. Overall, it is recommended to install soil sensors, such astensiometers and TDRs at a horizontal distance of 5~20 cm from the crop and a depth of10~20 cm from the soil surface while drip-tape is aligned close to the maize row.
