Foundation models(FMs)have rapidly evolved and have achieved signicant accomplishments in computer vision tasks.Specically,the prompt mechanism conveniently allows users to integrate image prior information into the m...Foundation models(FMs)have rapidly evolved and have achieved signicant accomplishments in computer vision tasks.Specically,the prompt mechanism conveniently allows users to integrate image prior information into the model,making it possible to apply models without any training.Therefore,we proposed a workflow based on foundation models and zero training to solve the tasks of photoacoustic(PA)image processing.We employed the Segment Anything Model(SAM)by setting simple prompts and integrating the model's outputs with prior knowledge of the imaged objects to accomplish various tasks,including:(1)removing the skin signal in three-dimensional PA image rendering;(2)dual speed-of-sound reconstruction,and(3)segmentation ofnger blood vessels.Through these demonstrations,we have concluded that FMs can be directly applied in PA imaging without the requirement for network design and training.This potentially allows for a hands-on,convenient approach to achieving efficient and accurate segmentation of PA images.This paper serves as a comprehensive tutorial,facilitating the mastery of the technique through the provision of code and sample datasets.展开更多
Voyager 1 occasionally detected sudden jumps of the local interstellar magnetic field strength since its heliopause crossing in August 2012.These events were believed to be associated with outward propagating solar wi...Voyager 1 occasionally detected sudden jumps of the local interstellar magnetic field strength since its heliopause crossing in August 2012.These events were believed to be associated with outward propagating solar wind shocks originating in the inner heliosphere.Here we investigate the correlation between interstellar shocks and large-scale solar wind events by means of numerical MHD simulation.The solar wind is simplified as a symmetric flow near the equatorial plane,and the interstellar neutrals are treated as a constant flow with a fixed density distribution along the upwind direction of the local interstellar medium.The charge exchanges between the solar wind plasma and the interstellar neutrals are taken into account.At a heliocentric distance of 1 AU,the solar wind data from OMNI,STEREO A and B during the period between 2010 and 2017 are used as the inner boundary conditions to drive the simulation.The simulation results showed that the solar wind gradually merges into large-scale structures as the radial distance increases,consistent with observations by New Horizons.After propagating into the inner heliosheath,the shocks are fully developed and the corresponding pressure pulses roughly agree with the observations by Voyager 2 in the inner heliosheath.The arrival of the shocks beyond the heliopause is estimated and found to be consistent with the observed signatures of interstellar shocks by Voyager 1.The possible origins of interstellar shocks in the inner heliosheath are discussed based on the simulation.展开更多
Dear Editor,Mink circovirus (MiCV), which is clustered in the genus Circovirus of the family Circoviridae, was first described in minks from farms in Dalian, China in 2013 (Lian et al.2014). The complete single-strand...Dear Editor,Mink circovirus (MiCV), which is clustered in the genus Circovirus of the family Circoviridae, was first described in minks from farms in Dalian, China in 2013 (Lian et al.2014). The complete single-stranded circular genome of the virus is 1,753 nucleotides long and contains two major open reading frames (ORFs), designated ORF1 (Rep gene)and ORF2 (Cap gene)(Lian et al. 2014;Ge et al. 2018).展开更多
Rosewood is a kind of high-quality and precious wood in China.The correct identification of rosewood species is of great significance to the import and export trade and species identification of furniture materials.In...Rosewood is a kind of high-quality and precious wood in China.The correct identification of rosewood species is of great significance to the import and export trade and species identification of furniture materials.In this paper,micro CT was used to obtain the micro images of CTOSS sections,radial sections and tangential sections of 24 kinds of rosewood,and the data sets were constructed.PCA method was used to reduce the dimension of four features including logical binary pattern,local configuration pattern,rotation invariant LBP,uniform LBP.These four fea-tures and one feature not reducing dimension(rotation invariant uniform LBP)was fused with Gray Level Co-Occurrence Matrix and Tamura features,respectively,a total of five fused features LBP+GLCM+Tamura,LCP+GLCM+Tamura,LBP_(P,R)^(u2)+GLCM+Tamura,LBP_(P,R)^(ri)+GLCM+Tamura and LBP_(P,R)^(riu2)+GLCM+Tamura were obtained.The five fused features were classified by extreme learning machine and BP neural network.The clas-sification effect of feature LBP_(P,R)^(u2)+GLCM+Tamura combined with extreme learning machine was the best,and the classification accuracy of CroSS,radial and tangential sections reached 100%,97.63%and 94.72%,respectively,which is 0.83%,2.77%and 5.70%higher than that of BP neural network.The classification running time of ELM is less than 1 s,and the classfcation eficiency is high.In condusion,the LBP_(P,R)^(u2)+GLCM+Tamura method com-bined with extreme learning machine can be used as a quick and acurate classifier,providing an efficient and feasible class ification method of rosewood.展开更多
Wide bandgap semiconductor materials are driving revolutionary improvements in the performance of high-power electronic devices. This study systematically evaluates the application prospects of wide bandgap semiconduc...Wide bandgap semiconductor materials are driving revolutionary improvements in the performance of high-power electronic devices. This study systematically evaluates the application prospects of wide bandgap semiconductor materials in high-power electronic devices. The research first compares the physical properties of major wide bandgap materials (such as silicon carbide SiC and gallium nitride GaN), analyzing their advantages over traditional silicon materials. Through theoretical calculations and experimental data analysis, the study assesses the performance of these materials in terms of high breakdown field, high thermal conductivity, and high electron saturation velocity. The research focuses on the application of SiC and GaN devices in power electronics, including high-voltage DC transmission, electric vehicle drive systems, and renewable energy conversion. The study also discusses the potential of wide bandgap materials in RF and microwave applications. However, the research also points out the challenges faced by wide bandgap semiconductor technology, such as material defect control, device reliability, and cost issues. To address these challenges, the study proposes solutions, including improving epitaxial growth techniques, optimizing device structure design, and developing new packaging methods. Finally, the research looks ahead to the prospects of wide bandgap semiconductors in emerging application areas such as quantum computing and terahertz communications. This study provides a comprehensive theoretical foundation and technology roadmap for the application of wide bandgap semiconductor materials in high-power electronic devices, contributing to the development of next-generation high-efficiency energy conversion and management systems.展开更多
In recent years,fine-scale gridded population data has been widely adopted for assessing and monitoring the Sustainable Development Goals(SDGs).However,the existing population disaggregation techniques struggle to gen...In recent years,fine-scale gridded population data has been widely adopted for assessing and monitoring the Sustainable Development Goals(SDGs).However,the existing population disaggregation techniques struggle to generate precise population grids for small areas with scarce data.To address this,we have introduced a novel,lightweight population gridding technique that integrates dasymetric mapping and point-based surface modeling,titled three-weight surface modeling.This method comprises three weights,each offering a unique perspective on population spatial heterogeneity.The first weight,termed building-volume weight,is equivalent to the preliminary results of assigning population based on building volume data.The second weight,termed POIcenter weight,comprises POI(Point of Interest)categories and aggregation patterns,aiming to articulate high-density population centers.It is computed using the neighborhood accumulation rule of Spearman’s correlation coefficients between POIs and population size.The third weight,termed POI-distance weight,represents varying decay rates of population with distance from high-density centers.This three-weight surface model facilitates dynamic adjustment of parameters to refine the building-volume weight according to the remaining POI-related weights,thereby generating a more precise population surface.Our analysis of the census population and the disaggregation outcomes from 544 villages in three counties of southern Guizhou Province,China(namely,Huishui,Luodian,and Pingtang)revealed that the three-weight surface model using local parameter groups outperformed individual dasymetric mapping or point-based surface modeling in terms of accuracy.Also,the 10 m population grid generated by this local parameter model(LPTW-POP)presented greater resolution and fewer errors(RMSE of 1109,MAE of 422,and MRE of 0.2630)compared to commonly use gridded population datasets like LandScan,WorldPop,and GHSPOP.展开更多
Background:A growing body of evidence supports the use of laparoscopic pancreaticoduodenectomy(LPD)as an efficient and feasible surgical technique.However,few studies have investigated its applicability in pancreatic ...Background:A growing body of evidence supports the use of laparoscopic pancreaticoduodenectomy(LPD)as an efficient and feasible surgical technique.However,few studies have investigated its applicability in pancreatic ductal adenocarcinoma(PDAC),and the long-term efficacy of LPD on PDAC remains unclear.This study aimed to compare the short-and long-term outcomes between LPD and open pancreaticoduodenectomy(OPD)for PDAC.Methods:The data of patients who had OPD or LPD for PDAC between January 2013 and September 2017 were retrieved.Their postoperative outcomes and survival were compared after propensity score matching.Results:A total of 309 patients were included.After a 2:1 matching,93 cases in the OPD group and 55 in the LPD group were identified.Delayed gastric emptying(DGE),particularly grade B/C DGE,occurred less frequently in the LPD group than in the OPD group(1.8%vs.36.6%,P<0.001;1.8%vs.22.6%,P=0.001).The overall complication rates were significantly lower in the LPD group than in the OPD group(49.1%vs.71.0%,P=0.008),whereas the rates of major complications were similar(10.9%vs.14.0%,P=0.590).In addition,the median overall survival was comparable between the two groups(20.0 vs.18.7 months,P=0.293).Conclusion:LPD was found to be technically feasible with efficacy similar to OPD for patients with PDAC.展开更多
A high-vanadium alloy composite layer was prepared on the surface of a carbon steel using cast composite technology,and the wear properties of the composite layer were investigated.The results showed that the microstr...A high-vanadium alloy composite layer was prepared on the surface of a carbon steel using cast composite technology,and the wear properties of the composite layer were investigated.The results showed that the microstructure of the composite layer was composed of primary vanadium carbides(VC),flake martensite,residual austenite,and fine VC.The hardness of the cast alloy layer was 63 HRC.The abrasive wear resistance and impact wear resistance were increased by 60%and 26%,respectively,compared with those of high-chromium cast iron.The excellent wear resistance of the cast alloy layer is attributed to the high-hardness primary vanadium carbide and the large number of fine secondary vanadium carbides precipitated out of the cast alloy layer.展开更多
Tumor hypoxia severely limits the therapeutic efficacy of photodynamic therapy(PDT) for solid tumors,which is highly dependent on tissue oxygen concentration.In this study,we developed a platinum(Ⅱ)-acetylide-based m...Tumor hypoxia severely limits the therapeutic efficacy of photodynamic therapy(PDT) for solid tumors,which is highly dependent on tissue oxygen concentration.In this study,we developed a platinum(Ⅱ)-acetylide-based metallacycle compound bearing six 1,4-dimethylnaphthalenes(DMN) groups,and controlled the photodynamic and photothermal effects of the compound by adjusting the power of 730 nm laser to achieve reversible sensitization,storage and release of 1~O_(2) within a single molecule.The compound formed nanoparticles by self-assembly and exhibited good water solubility and biocompatibility.Under laser irradiation,the strong spin-orbit coupling of platinum atoms in the metallacycle facilitated 1~O_(2) generation.The produced 1~O_(2) was captured by the DMN carriers and transported into the hypoxic tumor,where 1~O_(2) release was triggered owing to the good photothermal effect of the extended conjugation of the metallacycle.During therapy,the metallacycle serving as a photosensitizer,1~O_(2) carrier,and photothermal reagent,achieved the synergistic therapy of PDT/PTT,demonstrating the versatility of the metallacycle.This study proposes a new strategy to develop phototherapy agents that are suitable for hypoxic tumors.展开更多
基金support from Strategic Project of Precision Surgery,Tsinghua UniversityInitiative Scientific Research Program,Institute for Intelligent Healthcare,Tsinghua University+5 种基金Tsinghua-Foshan Institute of Advanced ManufacturingNational Natural Science Foundation of China(61735016)Beijing Nova Program(20230484308)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)Youth Elite Program of Beijing Friendship Hospital(YYQCJH2022-9)Science and Technology Program of Beijing Tongzhou District(KJ2023CX012).
文摘Foundation models(FMs)have rapidly evolved and have achieved signicant accomplishments in computer vision tasks.Specically,the prompt mechanism conveniently allows users to integrate image prior information into the model,making it possible to apply models without any training.Therefore,we proposed a workflow based on foundation models and zero training to solve the tasks of photoacoustic(PA)image processing.We employed the Segment Anything Model(SAM)by setting simple prompts and integrating the model's outputs with prior knowledge of the imaged objects to accomplish various tasks,including:(1)removing the skin signal in three-dimensional PA image rendering;(2)dual speed-of-sound reconstruction,and(3)segmentation ofnger blood vessels.Through these demonstrations,we have concluded that FMs can be directly applied in PA imaging without the requirement for network design and training.This potentially allows for a hands-on,convenient approach to achieving efficient and accurate segmentation of PA images.This paper serves as a comprehensive tutorial,facilitating the mastery of the technique through the provision of code and sample datasets.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences Grant No.XDB41000000,XDA15052500,XDA17010301,QYZDJ-SSW-JSC028,NNSFC grants 41874171,41674146,41731070,and 41774179the Specialized Research Fund for State Key Laboratories of China and NSSC research fund for key development directions,and the Civil Aerospace"13th Five-Year Plan"PreliminaryResearch in space science(project No:D020301,D030202)。
文摘Voyager 1 occasionally detected sudden jumps of the local interstellar magnetic field strength since its heliopause crossing in August 2012.These events were believed to be associated with outward propagating solar wind shocks originating in the inner heliosphere.Here we investigate the correlation between interstellar shocks and large-scale solar wind events by means of numerical MHD simulation.The solar wind is simplified as a symmetric flow near the equatorial plane,and the interstellar neutrals are treated as a constant flow with a fixed density distribution along the upwind direction of the local interstellar medium.The charge exchanges between the solar wind plasma and the interstellar neutrals are taken into account.At a heliocentric distance of 1 AU,the solar wind data from OMNI,STEREO A and B during the period between 2010 and 2017 are used as the inner boundary conditions to drive the simulation.The simulation results showed that the solar wind gradually merges into large-scale structures as the radial distance increases,consistent with observations by New Horizons.After propagating into the inner heliosheath,the shocks are fully developed and the corresponding pressure pulses roughly agree with the observations by Voyager 2 in the inner heliosheath.The arrival of the shocks beyond the heliopause is estimated and found to be consistent with the observed signatures of interstellar shocks by Voyager 1.The possible origins of interstellar shocks in the inner heliosheath are discussed based on the simulation.
基金financially supported by the National Key Research and Development Program of China (No. 2017YFD0500103)the National Natural Science Foundation of China (No. 31772747)+2 种基金the Science and Technology Development Project of Jilin Province (No. 20170623043TC)the Program for JLU Science and Technology Innovative Research Team (JLUSTIRT, No. 2017TD-28)the Fundamental Research Funds for the Central Universities
文摘Dear Editor,Mink circovirus (MiCV), which is clustered in the genus Circovirus of the family Circoviridae, was first described in minks from farms in Dalian, China in 2013 (Lian et al.2014). The complete single-stranded circular genome of the virus is 1,753 nucleotides long and contains two major open reading frames (ORFs), designated ORF1 (Rep gene)and ORF2 (Cap gene)(Lian et al. 2014;Ge et al. 2018).
基金The Natural Science Foundation of Shandong Province,China(Grant No.ZR2020QC174)The Application of Computed Tomography(CT)Scanning Technology to Damage Detection of Timber Frames of Architectural Heritage.The Taishan Scholar Project of Shandong Province,China(Grant No.2015162).
文摘Rosewood is a kind of high-quality and precious wood in China.The correct identification of rosewood species is of great significance to the import and export trade and species identification of furniture materials.In this paper,micro CT was used to obtain the micro images of CTOSS sections,radial sections and tangential sections of 24 kinds of rosewood,and the data sets were constructed.PCA method was used to reduce the dimension of four features including logical binary pattern,local configuration pattern,rotation invariant LBP,uniform LBP.These four fea-tures and one feature not reducing dimension(rotation invariant uniform LBP)was fused with Gray Level Co-Occurrence Matrix and Tamura features,respectively,a total of five fused features LBP+GLCM+Tamura,LCP+GLCM+Tamura,LBP_(P,R)^(u2)+GLCM+Tamura,LBP_(P,R)^(ri)+GLCM+Tamura and LBP_(P,R)^(riu2)+GLCM+Tamura were obtained.The five fused features were classified by extreme learning machine and BP neural network.The clas-sification effect of feature LBP_(P,R)^(u2)+GLCM+Tamura combined with extreme learning machine was the best,and the classification accuracy of CroSS,radial and tangential sections reached 100%,97.63%and 94.72%,respectively,which is 0.83%,2.77%and 5.70%higher than that of BP neural network.The classification running time of ELM is less than 1 s,and the classfcation eficiency is high.In condusion,the LBP_(P,R)^(u2)+GLCM+Tamura method com-bined with extreme learning machine can be used as a quick and acurate classifier,providing an efficient and feasible class ification method of rosewood.
文摘Wide bandgap semiconductor materials are driving revolutionary improvements in the performance of high-power electronic devices. This study systematically evaluates the application prospects of wide bandgap semiconductor materials in high-power electronic devices. The research first compares the physical properties of major wide bandgap materials (such as silicon carbide SiC and gallium nitride GaN), analyzing their advantages over traditional silicon materials. Through theoretical calculations and experimental data analysis, the study assesses the performance of these materials in terms of high breakdown field, high thermal conductivity, and high electron saturation velocity. The research focuses on the application of SiC and GaN devices in power electronics, including high-voltage DC transmission, electric vehicle drive systems, and renewable energy conversion. The study also discusses the potential of wide bandgap materials in RF and microwave applications. However, the research also points out the challenges faced by wide bandgap semiconductor technology, such as material defect control, device reliability, and cost issues. To address these challenges, the study proposes solutions, including improving epitaxial growth techniques, optimizing device structure design, and developing new packaging methods. Finally, the research looks ahead to the prospects of wide bandgap semiconductors in emerging application areas such as quantum computing and terahertz communications. This study provides a comprehensive theoretical foundation and technology roadmap for the application of wide bandgap semiconductor materials in high-power electronic devices, contributing to the development of next-generation high-efficiency energy conversion and management systems.
基金the support of the Natural Science Foundation of Shanghai Municipality(No.24ZR1420500)the Project of Yulin Science,and Technology Light(No.2024-KJZG-KXJ-005)the Project of International Research Center of Big Data for SDGs(No.CBAS2024SDG005).
文摘In recent years,fine-scale gridded population data has been widely adopted for assessing and monitoring the Sustainable Development Goals(SDGs).However,the existing population disaggregation techniques struggle to generate precise population grids for small areas with scarce data.To address this,we have introduced a novel,lightweight population gridding technique that integrates dasymetric mapping and point-based surface modeling,titled three-weight surface modeling.This method comprises three weights,each offering a unique perspective on population spatial heterogeneity.The first weight,termed building-volume weight,is equivalent to the preliminary results of assigning population based on building volume data.The second weight,termed POIcenter weight,comprises POI(Point of Interest)categories and aggregation patterns,aiming to articulate high-density population centers.It is computed using the neighborhood accumulation rule of Spearman’s correlation coefficients between POIs and population size.The third weight,termed POI-distance weight,represents varying decay rates of population with distance from high-density centers.This three-weight surface model facilitates dynamic adjustment of parameters to refine the building-volume weight according to the remaining POI-related weights,thereby generating a more precise population surface.Our analysis of the census population and the disaggregation outcomes from 544 villages in three counties of southern Guizhou Province,China(namely,Huishui,Luodian,and Pingtang)revealed that the three-weight surface model using local parameter groups outperformed individual dasymetric mapping or point-based surface modeling in terms of accuracy.Also,the 10 m population grid generated by this local parameter model(LPTW-POP)presented greater resolution and fewer errors(RMSE of 1109,MAE of 422,and MRE of 0.2630)compared to commonly use gridded population datasets like LandScan,WorldPop,and GHSPOP.
基金This study was supported by Technology Program of Zhejiang Province,China(2015C03049)
文摘Background:A growing body of evidence supports the use of laparoscopic pancreaticoduodenectomy(LPD)as an efficient and feasible surgical technique.However,few studies have investigated its applicability in pancreatic ductal adenocarcinoma(PDAC),and the long-term efficacy of LPD on PDAC remains unclear.This study aimed to compare the short-and long-term outcomes between LPD and open pancreaticoduodenectomy(OPD)for PDAC.Methods:The data of patients who had OPD or LPD for PDAC between January 2013 and September 2017 were retrieved.Their postoperative outcomes and survival were compared after propensity score matching.Results:A total of 309 patients were included.After a 2:1 matching,93 cases in the OPD group and 55 in the LPD group were identified.Delayed gastric emptying(DGE),particularly grade B/C DGE,occurred less frequently in the LPD group than in the OPD group(1.8%vs.36.6%,P<0.001;1.8%vs.22.6%,P=0.001).The overall complication rates were significantly lower in the LPD group than in the OPD group(49.1%vs.71.0%,P=0.008),whereas the rates of major complications were similar(10.9%vs.14.0%,P=0.590).In addition,the median overall survival was comparable between the two groups(20.0 vs.18.7 months,P=0.293).Conclusion:LPD was found to be technically feasible with efficacy similar to OPD for patients with PDAC.
基金The authors greatly acknowledge the National Natural Science Foundation of China(No.51171060)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1234).
文摘A high-vanadium alloy composite layer was prepared on the surface of a carbon steel using cast composite technology,and the wear properties of the composite layer were investigated.The results showed that the microstructure of the composite layer was composed of primary vanadium carbides(VC),flake martensite,residual austenite,and fine VC.The hardness of the cast alloy layer was 63 HRC.The abrasive wear resistance and impact wear resistance were increased by 60%and 26%,respectively,compared with those of high-chromium cast iron.The excellent wear resistance of the cast alloy layer is attributed to the high-hardness primary vanadium carbide and the large number of fine secondary vanadium carbides precipitated out of the cast alloy layer.
基金supported by the National Natural Science Foundation of China (22075148,22161160318)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(21KJB150013)the Youth Fund Project of Jiangsu Natural Science Foundation (BK20210583)。
文摘Tumor hypoxia severely limits the therapeutic efficacy of photodynamic therapy(PDT) for solid tumors,which is highly dependent on tissue oxygen concentration.In this study,we developed a platinum(Ⅱ)-acetylide-based metallacycle compound bearing six 1,4-dimethylnaphthalenes(DMN) groups,and controlled the photodynamic and photothermal effects of the compound by adjusting the power of 730 nm laser to achieve reversible sensitization,storage and release of 1~O_(2) within a single molecule.The compound formed nanoparticles by self-assembly and exhibited good water solubility and biocompatibility.Under laser irradiation,the strong spin-orbit coupling of platinum atoms in the metallacycle facilitated 1~O_(2) generation.The produced 1~O_(2) was captured by the DMN carriers and transported into the hypoxic tumor,where 1~O_(2) release was triggered owing to the good photothermal effect of the extended conjugation of the metallacycle.During therapy,the metallacycle serving as a photosensitizer,1~O_(2) carrier,and photothermal reagent,achieved the synergistic therapy of PDT/PTT,demonstrating the versatility of the metallacycle.This study proposes a new strategy to develop phototherapy agents that are suitable for hypoxic tumors.
