Dear Editor,Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR)is a powerful and versatile gene editing system that has been extensively utilized in various animals and plants,which holds enormous potent...Dear Editor,Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR)is a powerful and versatile gene editing system that has been extensively utilized in various animals and plants,which holds enormous potential and value for scientific research and breeding.However,single-targeted CRISPR can only induce a few base deletions,insertions,or substitution.Ideally,thesemutations result in premature termination of the protein encoded by the target gene,leading to a loss of function[1].展开更多
With the advent of advanced sequencing technologies,non-coding RNAs(ncRNAs)are increasingly pivotal and play highly regulated roles in the modulation of diverse aspects of plant growth and stress response.This include...With the advent of advanced sequencing technologies,non-coding RNAs(ncRNAs)are increasingly pivotal and play highly regulated roles in the modulation of diverse aspects of plant growth and stress response.This includes a spectrum of ncRNA classes,ranging from small RNAs to long non-coding RNAs(lncRNAs).Notably,among these,lncRNAs emerge as significant and intricate components within the broader ncRNA regulatory networks.Here,we categorize ncRNAs based on their length and structure into small RNAs,medium-sized ncRNAs,lncRNAs,and circle RNAs.Furthermore,the review delves into the detailed biosynthesis and origin of these ncRNAs.Subsequently,we emphasize the diverse regulatory mechanisms employed by lncRNAs that are located at various gene regions of coding genes,embodying promoters,5’UTRs,introns,exons,and 3’UTR regions.Furthermore,we elucidate these regulatory modes through one or two concrete examples.Besides,lncRNAs have emerged as novel central components that participate in phase separation processes.Moreover,we illustrate the coordinated regulatory mechanisms among lncRNAs,miRNAs,and siRNAs with a particular emphasis on the central role of lncRNAs in serving as sponges,precursors,spliceosome,stabilization,scaffolds,or interaction factors to bridge interactions with other ncRNAs.The review also sheds light on the intriguing possibility that some ncRNAs may encode functional micropeptides.Therefore,the review underscores the emergent roles of ncRNAs as potent regulatory factors that significantly enrich the regulatory network governing plant growth,development,and responses to environmental stimuli.There are yet-to-be-discovered roles of ncRNAs waiting for us to explore.展开更多
Fruits are major sources of essential nutrients and serve as staple foods in some areas of the world.The increasing human population and changes in climate experienced worldwide make it urgent to the production of fru...Fruits are major sources of essential nutrients and serve as staple foods in some areas of the world.The increasing human population and changes in climate experienced worldwide make it urgent to the production of fruit crops with high yield and enhanced adaptation to the environment,for which conventional breeding is unlikely to meet the demand.Fortunately,clustered regularly interspaced short palindromic repeat(CRISPR)technology paves the way toward a new horizon for fruit crop improvement and consequently revolutionizes plant breeding.In this review,the mechanism and optimization of the CRISPR system and its application to fruit crops,including resistance to biotic and abiotic stresses,fruit quality improvement,and domestication are highlighted.Controversies and future perspectives are discussed as well.展开更多
Ripening of the model fruit tomato(Solanum lycopersicum)is controlled by a transcription factor network including NAC(NAM,ATAF1/2,and CUC2)domain proteins such as No-ripening(NOR),SlNAC1,and SlNAC4,but very little is ...Ripening of the model fruit tomato(Solanum lycopersicum)is controlled by a transcription factor network including NAC(NAM,ATAF1/2,and CUC2)domain proteins such as No-ripening(NOR),SlNAC1,and SlNAC4,but very little is known about the NAC targets or how they regulate ripening.Here,we conducted a systematic search of fruit-expressed NAC genes and showed that silencing NOR-like1(Solyc07g063420)using virus-induced gene silencing(VIGS)inhibited specific aspects of ripening.Ripening initiation was delayed by 14 days when NOR-like1 function was inactivated by CRISPR/Cas9 and fruits showed obviously reduced ethylene production,retarded softening and chlorophyll loss,and reduced lycopene accumulation.RNA-sequencing profiling and gene promoter analysis suggested that genes involved in ethylene biosynthesis(SlACS2,SlACS4),color formation(SlGgpps2,SlSGR1),and cell wall metabolism(SlPG2a,SlPL,SlCEL2,and SlEXP1)are direct targets of NOR-like1.Electrophoretic mobility shift assays(EMSA),chromatin immunoprecipitation-quantitative PCR(ChIP-qPCR),and dual-luciferase reporter assay(DLR)confirmed that NOR-like1 bound to the promoters of these genes both in vitro and in vivo,and activated their expression.Our findings demonstrate that NOR-like1 is a new positive regulator of tomato fruit ripening,with an important role in the transcriptional regulatory network.展开更多
The effect of self-reactivation on the CO_(2) capture capacity of the spent calcium based sorbent was investigated in a dual-fixed bed reactor.The sampled sorbents from the dual-fixed bed reactor were sent for XRD,SEM...The effect of self-reactivation on the CO_(2) capture capacity of the spent calcium based sorbent was investigated in a dual-fixed bed reactor.The sampled sorbents from the dual-fixed bed reactor were sent for XRD,SEM and N_2 adsorption analysis to explain the self-reactivation mechanism.The results show that the CaO in the spent sorbent discharged from the calciner absorbs the vapor in the air to form Ca(OH)_(2) and further Ca(OH)_(2)·2 H_(2) O under environmental conditions,during which process the CO_(2) capture capacity of the spent sorbent can be self-reactivated.The microstructure of the spent sorbent is improved by the self-reactivation process,resulting in more porous microstructure,higher BET surface area and pore volume.Compared with the calcined spent sorbent that has experienced 20 cycles,the pore volume and BET surface area are increased by 6.69 times and 56.3% after self-reactivation when φ=170%.The improved microstructure makes it easier for the CO_(2) diffusion and carbonation reaction in the sorbent.Therefore,the CO_(2) capture capacity of the spent sorbent is enhanced by self-reactivation process.A self-reactivation process coupled with calcium looping process was proposed to reuse the discharged spent calcium based sorbent from the calciner.Higher average carbonation conversion and CO_(2) capture efficiency can be achieved when self-reactivated spent sorbent is used as supplementary sorbent in the calciner rather than fresh CaCO_(3) under the same conditions.展开更多
The tomato encode four functional DCL families,of which DCL2 is poorly studied.Here,we generated loss-of-function mutants for a tomato DCL2 gene,dcl2b,and we identified its major role in defending against tomato mosai...The tomato encode four functional DCL families,of which DCL2 is poorly studied.Here,we generated loss-of-function mutants for a tomato DCL2 gene,dcl2b,and we identified its major role in defending against tomato mosaic virus in relation to both natural and manual infections.Genome-wide small RNA expression profiling revealed that DCL2b was required for the processing 22-nt small RNAs,including a few species of miRNAs.Interestingly,these DCL2b-dependent 22-nt miRNAs functioned similarly to the DCL1-produced 22-nt miRNAs in Arabidopsis and could serve as triggers to generate a class of secondary siRNAs.In particular,the majority of secondary siRNAs were derived from plant defense genes when the plants were challenged with viruses.We also examined differentially expressed genes in dcl2b through RNA-seq and observed that numerous genes were associated with mitochondrial metabolism and hormone signaling under virus-free conditions.Notably,when the loss-of-function dcl2b mutant was challenged with tomato mosaic virus,a group of defense response genes was activated,whereas the genes related to lipid metabolism were suppressed.Together,our findings provided new insights into the roles of tomato DCL2b in small RNA biogenesis and in antiviral defense.展开更多
The accumulation of nutrients and flavors are important factors that determine the consumption of tomato fruit.Carotenoids,polyphenol and vitamin C belong to antioxidant molecules and have been proven to regulate seve...The accumulation of nutrients and flavors are important factors that determine the consumption of tomato fruit.Carotenoids,polyphenol and vitamin C belong to antioxidant molecules and have been proven to regulate several biochemical processes and prevent many chronic diseases.In recent years,significant progress has been made in our understanding of the biosynthetic pathway and regulatory networks of these compounds in tomatoes.Numerous genes have been determined which promote the accumulation of these nutrients,such as SlNAC1,SlCCD,SlHY5.Meanwhile,since the mechanisms that control nutrient metabolism during fruit ripening are systematic and sophisticated,there are still many unknown factors that affect their content,which need to be further explored.In addition,not only are nutritional properties important,but flavor profiles play a core role in the market for tomato production.However,it is generally accepted by consumers that many tomato varieties have declined nutrient content and little flavor with people's pursuit of fruit yield and size.Hence,improving their levels are the main objectives of many breeding programs.In order to effectively enhance the nutritional and flavor quality of tomato fruits,we reviewed the critical steps in metabolic pathways of these important nutrients and flavor compounds,summarized key regulators for controlling the accumulation of these compounds,and hope to offer valuable candidate genes for the production of high-quality tomato fruits.展开更多
Lead sulfide (PbS) nanorods with a high aspect ratio were prepared by a novel thioglycolic acid assisted hydrothermal method. X-ray diffraction and transmission electron microscopy revealed that the product was rod-...Lead sulfide (PbS) nanorods with a high aspect ratio were prepared by a novel thioglycolic acid assisted hydrothermal method. X-ray diffraction and transmission electron microscopy revealed that the product was rod-like PbS with cubic rock-salt structure. Further characterizations by selected area electron diffraction and high-resolution transmission electron microscopy showed that the PbS nanorods were single crystalline in nature. Furthermore, the mechanism and critical factors for the hydrothermal synthesis of the nanorods have been discussed.展开更多
In this study,integrative metabolomics and transcriptomics analyses were conducted to investigate the effects of 1-methylcyclopropene(1-MCP)on apple fruit quality during long-term cold storage.The results showed that ...In this study,integrative metabolomics and transcriptomics analyses were conducted to investigate the effects of 1-methylcyclopropene(1-MCP)on apple fruit quality during long-term cold storage.The results showed that 1-MCP(1μL/L)treatment could maintain fruits apparent quality(i.e.external color and firmness),inhibit the increase of rot rate and soluble solids content/titratable acidity ratio,decrease ethylene release,and respiratory intensity during cold storage,and extend shelf life.Moreover,1-MCP had long-term effects on the accumulation of many qualities related to metabolite and gene expression in fruits.1-MCP affected genes related to metabolism at the early stage of storage,specifically those of the glycolysis and tricarboxylic acid cycle pathways.Genes related to the degradation of sucrose,starch,and cellulose were inhibited,and some starch and cellulose synthesis genes were up-regulated by 1-MCP.Apart from ethylene synthesis and signal transduction being inhibited by 1-MCP,several enzymes(pectinesterase,pectate lyase,polygalacturonase)were involved in pectin degradation,and degradation products of the cell wall(i.e.D-galacturonic acid and D-glucuronic acid)were also strongly inhibited,further maintaining fruit firmness.Cysteine,as precursor glutathione(GSH)related to plant resistance,up-regulated the synthase gene.However,the expression of genes related to cyanoalanine syn-thase and amino acid utilization pathways was suppressed by 1-MCP Collectively,1-MCP could maintain the postharvest quality of apple fruits.展开更多
High-frequency stock trend prediction using machine learners has raised substantial interest in literature. Nevertheless, there is no gold standard to select the inputs for the learners. This paper investigates the ap...High-frequency stock trend prediction using machine learners has raised substantial interest in literature. Nevertheless, there is no gold standard to select the inputs for the learners. This paper investigates the approach of adaptive input selection(AIS) for the trend prediction of high-frequency stock index price and compares it with the commonly used deterministic input setting(DIS) approach.The DIS approach is implemented through computation of technical indicator values on deterministic period parameters. The AIS approach selects the most suitable indicators and their parameters for the time-varying dataset using feature selection methods. Two state-of-the-art machine learners, support vector machine(SVM) and artificial neural network(ANN), are adopted as learning models. Accuracy and F-measure of SVM and ANN models with both the approaches are computed based on the high-frequency data of CSI 300 index. The results suggest that the AIS approach using t-statistics,information gain and ROC methods can achieve better prediction performance than the DIS approach.Also, the investment performance evaluation shows that the AIS approach with the same three feature selection methods provides significantly higher returns than the DIS approach.展开更多
The blue-emitting YPO4 phosphors doped with Yb3+ were prepared by a simple hydrothermal method. All the products were characterized by XRD and TEM, which revealed that they were zircon structure with leaf-like morpho...The blue-emitting YPO4 phosphors doped with Yb3+ were prepared by a simple hydrothermal method. All the products were characterized by XRD and TEM, which revealed that they were zircon structure with leaf-like morphology. According to the analysis of photoluminescence spectra, upon ultraviolet (275 nm) excitation, the Yb3+ doped YPO4 phosphor showed an intense blue emission composed of two main bands at 420 and 620 nm assigned to charge transfer state (CTS) → 2Fs/2 and CTS →ZF7/2, respectively. Moreover, the optimum doping concentration of Yb3+ in YPO4 phosphor was 1%, which exhibited the maximum emission intensity. The possible physical mechanism of concentration quenching was discussed, and the critical transfer distance determined to be 23.889 A. In particular, the color purity of the as-synthesized Yb3+ doped YPO4 phosphor was as high as 83%, which made it an excellent candidate for blue-emitting materials.展开更多
The role of computed tomography(CT)images in forensic identification has been widely recognized.Such images can provide an important basis for identification of the cause of death in complicated and difficult cases,in...The role of computed tomography(CT)images in forensic identification has been widely recognized.Such images can provide an important basis for identification of the cause of death in complicated and difficult cases,including falls from a height,drowning,explosion and gunshot cases,traffic accidents,and sudden death.However,few reports have focused on the application of CT images in cases of death caused by sharp object injuries.Therefore,the CT images and autopsy findings were compared in a case of death caused by sharp object injuries to the chest and abdomen,and the importance of CT images in cases of death from common sharp object injuries is herein discussed.展开更多
基金We thank Professor Pengcheng Wei of Anhui Agricultural University for his guidance on the experimental methods.This work was supported by the National Key Research and Development Program of China(Grant No.2022YFD2100101)the Joint NSFC-ISF Research Program(Grant No.32061143022)+1 种基金the 2115 Talent Development Program of China Agricultural University(Grant No.1061-00109017)to HZthe National Natural Science Foundation of China(Grant No.3217180159).
文摘Dear Editor,Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR)is a powerful and versatile gene editing system that has been extensively utilized in various animals and plants,which holds enormous potential and value for scientific research and breeding.However,single-targeted CRISPR can only induce a few base deletions,insertions,or substitution.Ideally,thesemutations result in premature termination of the protein encoded by the target gene,leading to a loss of function[1].
基金This review was supported by the National Key Research and Development Program of China(Grant No.2022YFD2100101)the National Natural Science Foundation of China to G.Z.(Grant No.32302623)+1 种基金the Joint NSFC-ISF Research Program(Grant No.32061143022)the National Natural Sciences Foundation of China(Grant No.32172639).
文摘With the advent of advanced sequencing technologies,non-coding RNAs(ncRNAs)are increasingly pivotal and play highly regulated roles in the modulation of diverse aspects of plant growth and stress response.This includes a spectrum of ncRNA classes,ranging from small RNAs to long non-coding RNAs(lncRNAs).Notably,among these,lncRNAs emerge as significant and intricate components within the broader ncRNA regulatory networks.Here,we categorize ncRNAs based on their length and structure into small RNAs,medium-sized ncRNAs,lncRNAs,and circle RNAs.Furthermore,the review delves into the detailed biosynthesis and origin of these ncRNAs.Subsequently,we emphasize the diverse regulatory mechanisms employed by lncRNAs that are located at various gene regions of coding genes,embodying promoters,5’UTRs,introns,exons,and 3’UTR regions.Furthermore,we elucidate these regulatory modes through one or two concrete examples.Besides,lncRNAs have emerged as novel central components that participate in phase separation processes.Moreover,we illustrate the coordinated regulatory mechanisms among lncRNAs,miRNAs,and siRNAs with a particular emphasis on the central role of lncRNAs in serving as sponges,precursors,spliceosome,stabilization,scaffolds,or interaction factors to bridge interactions with other ncRNAs.The review also sheds light on the intriguing possibility that some ncRNAs may encode functional micropeptides.Therefore,the review underscores the emergent roles of ncRNAs as potent regulatory factors that significantly enrich the regulatory network governing plant growth,development,and responses to environmental stimuli.There are yet-to-be-discovered roles of ncRNAs waiting for us to explore.
基金supported by grants from National Key R&D Program of China(2016YFD0400901)National Natural Sciences Foundation of China(31622050 and 31672208)to H.Z.T.W.was supported by a fellowship from the Chinese Scholarship Council(201706350174).
文摘Fruits are major sources of essential nutrients and serve as staple foods in some areas of the world.The increasing human population and changes in climate experienced worldwide make it urgent to the production of fruit crops with high yield and enhanced adaptation to the environment,for which conventional breeding is unlikely to meet the demand.Fortunately,clustered regularly interspaced short palindromic repeat(CRISPR)technology paves the way toward a new horizon for fruit crop improvement and consequently revolutionizes plant breeding.In this review,the mechanism and optimization of the CRISPR system and its application to fruit crops,including resistance to biotic and abiotic stresses,fruit quality improvement,and domestication are highlighted.Controversies and future perspectives are discussed as well.
基金This work was supported by the National Natural Science Foundation of China(NSFC 31571898,31772029,31572173).
文摘Ripening of the model fruit tomato(Solanum lycopersicum)is controlled by a transcription factor network including NAC(NAM,ATAF1/2,and CUC2)domain proteins such as No-ripening(NOR),SlNAC1,and SlNAC4,but very little is known about the NAC targets or how they regulate ripening.Here,we conducted a systematic search of fruit-expressed NAC genes and showed that silencing NOR-like1(Solyc07g063420)using virus-induced gene silencing(VIGS)inhibited specific aspects of ripening.Ripening initiation was delayed by 14 days when NOR-like1 function was inactivated by CRISPR/Cas9 and fruits showed obviously reduced ethylene production,retarded softening and chlorophyll loss,and reduced lycopene accumulation.RNA-sequencing profiling and gene promoter analysis suggested that genes involved in ethylene biosynthesis(SlACS2,SlACS4),color formation(SlGgpps2,SlSGR1),and cell wall metabolism(SlPG2a,SlPL,SlCEL2,and SlEXP1)are direct targets of NOR-like1.Electrophoretic mobility shift assays(EMSA),chromatin immunoprecipitation-quantitative PCR(ChIP-qPCR),and dual-luciferase reporter assay(DLR)confirmed that NOR-like1 bound to the promoters of these genes both in vitro and in vivo,and activated their expression.Our findings demonstrate that NOR-like1 is a new positive regulator of tomato fruit ripening,with an important role in the transcriptional regulatory network.
基金supported by the National Natural Science Foundation of China (51706094)。
文摘The effect of self-reactivation on the CO_(2) capture capacity of the spent calcium based sorbent was investigated in a dual-fixed bed reactor.The sampled sorbents from the dual-fixed bed reactor were sent for XRD,SEM and N_2 adsorption analysis to explain the self-reactivation mechanism.The results show that the CaO in the spent sorbent discharged from the calciner absorbs the vapor in the air to form Ca(OH)_(2) and further Ca(OH)_(2)·2 H_(2) O under environmental conditions,during which process the CO_(2) capture capacity of the spent sorbent can be self-reactivated.The microstructure of the spent sorbent is improved by the self-reactivation process,resulting in more porous microstructure,higher BET surface area and pore volume.Compared with the calcined spent sorbent that has experienced 20 cycles,the pore volume and BET surface area are increased by 6.69 times and 56.3% after self-reactivation when φ=170%.The improved microstructure makes it easier for the CO_(2) diffusion and carbonation reaction in the sorbent.Therefore,the CO_(2) capture capacity of the spent sorbent is enhanced by self-reactivation process.A self-reactivation process coupled with calcium looping process was proposed to reuse the discharged spent calcium based sorbent from the calciner.Higher average carbonation conversion and CO_(2) capture efficiency can be achieved when self-reactivated spent sorbent is used as supplementary sorbent in the calciner rather than fresh CaCO_(3) under the same conditions.
基金This research was supported by grants from the National Natural Science Foundation of China(31471921,91540118,31622050,and 31672208)to H.ZT.W.was supported by a fellowship from the Chinese Scholarship Council.
文摘The tomato encode four functional DCL families,of which DCL2 is poorly studied.Here,we generated loss-of-function mutants for a tomato DCL2 gene,dcl2b,and we identified its major role in defending against tomato mosaic virus in relation to both natural and manual infections.Genome-wide small RNA expression profiling revealed that DCL2b was required for the processing 22-nt small RNAs,including a few species of miRNAs.Interestingly,these DCL2b-dependent 22-nt miRNAs functioned similarly to the DCL1-produced 22-nt miRNAs in Arabidopsis and could serve as triggers to generate a class of secondary siRNAs.In particular,the majority of secondary siRNAs were derived from plant defense genes when the plants were challenged with viruses.We also examined differentially expressed genes in dcl2b through RNA-seq and observed that numerous genes were associated with mitochondrial metabolism and hormone signaling under virus-free conditions.Notably,when the loss-of-function dcl2b mutant was challenged with tomato mosaic virus,a group of defense response genes was activated,whereas the genes related to lipid metabolism were suppressed.Together,our findings provided new insights into the roles of tomato DCL2b in small RNA biogenesis and in antiviral defense.
文摘The accumulation of nutrients and flavors are important factors that determine the consumption of tomato fruit.Carotenoids,polyphenol and vitamin C belong to antioxidant molecules and have been proven to regulate several biochemical processes and prevent many chronic diseases.In recent years,significant progress has been made in our understanding of the biosynthetic pathway and regulatory networks of these compounds in tomatoes.Numerous genes have been determined which promote the accumulation of these nutrients,such as SlNAC1,SlCCD,SlHY5.Meanwhile,since the mechanisms that control nutrient metabolism during fruit ripening are systematic and sophisticated,there are still many unknown factors that affect their content,which need to be further explored.In addition,not only are nutritional properties important,but flavor profiles play a core role in the market for tomato production.However,it is generally accepted by consumers that many tomato varieties have declined nutrient content and little flavor with people's pursuit of fruit yield and size.Hence,improving their levels are the main objectives of many breeding programs.In order to effectively enhance the nutritional and flavor quality of tomato fruits,we reviewed the critical steps in metabolic pathways of these important nutrients and flavor compounds,summarized key regulators for controlling the accumulation of these compounds,and hope to offer valuable candidate genes for the production of high-quality tomato fruits.
基金the finan cial supports of 863 project(No.2001AA513023)the National Natural Science Foundation of China(No.60225010) the Zhejian g Provincial Natural Science Foundation of China(No.601092).
文摘Lead sulfide (PbS) nanorods with a high aspect ratio were prepared by a novel thioglycolic acid assisted hydrothermal method. X-ray diffraction and transmission electron microscopy revealed that the product was rod-like PbS with cubic rock-salt structure. Further characterizations by selected area electron diffraction and high-resolution transmission electron microscopy showed that the PbS nanorods were single crystalline in nature. Furthermore, the mechanism and critical factors for the hydrothermal synthesis of the nanorods have been discussed.
基金the National Key Research and Development Program of China(2016YFD0400901)the 2115 Talent Development Program of China Agricultural University(1061-00109019).
文摘In this study,integrative metabolomics and transcriptomics analyses were conducted to investigate the effects of 1-methylcyclopropene(1-MCP)on apple fruit quality during long-term cold storage.The results showed that 1-MCP(1μL/L)treatment could maintain fruits apparent quality(i.e.external color and firmness),inhibit the increase of rot rate and soluble solids content/titratable acidity ratio,decrease ethylene release,and respiratory intensity during cold storage,and extend shelf life.Moreover,1-MCP had long-term effects on the accumulation of many qualities related to metabolite and gene expression in fruits.1-MCP affected genes related to metabolism at the early stage of storage,specifically those of the glycolysis and tricarboxylic acid cycle pathways.Genes related to the degradation of sucrose,starch,and cellulose were inhibited,and some starch and cellulose synthesis genes were up-regulated by 1-MCP.Apart from ethylene synthesis and signal transduction being inhibited by 1-MCP,several enzymes(pectinesterase,pectate lyase,polygalacturonase)were involved in pectin degradation,and degradation products of the cell wall(i.e.D-galacturonic acid and D-glucuronic acid)were also strongly inhibited,further maintaining fruit firmness.Cysteine,as precursor glutathione(GSH)related to plant resistance,up-regulated the synthase gene.However,the expression of genes related to cyanoalanine syn-thase and amino acid utilization pathways was suppressed by 1-MCP Collectively,1-MCP could maintain the postharvest quality of apple fruits.
基金Supported by the Philosophy and Social Science Fund of Higher Institutions of Jiangsu Province(2017SJB0234)Natural Science Foundation of Higher Education Institutions of Jiangsu Province(17KJB120004)+2 种基金MOE Layout Foundation of Humanities and Social Sciences(17YJA790101)the National Natural Science Foundation of China(71471081,71501088,71671082)MOE Project of Humanities and Social Sciences(17YJC630128)
文摘High-frequency stock trend prediction using machine learners has raised substantial interest in literature. Nevertheless, there is no gold standard to select the inputs for the learners. This paper investigates the approach of adaptive input selection(AIS) for the trend prediction of high-frequency stock index price and compares it with the commonly used deterministic input setting(DIS) approach.The DIS approach is implemented through computation of technical indicator values on deterministic period parameters. The AIS approach selects the most suitable indicators and their parameters for the time-varying dataset using feature selection methods. Two state-of-the-art machine learners, support vector machine(SVM) and artificial neural network(ANN), are adopted as learning models. Accuracy and F-measure of SVM and ANN models with both the approaches are computed based on the high-frequency data of CSI 300 index. The results suggest that the AIS approach using t-statistics,information gain and ROC methods can achieve better prediction performance than the DIS approach.Also, the investment performance evaluation shows that the AIS approach with the same three feature selection methods provides significantly higher returns than the DIS approach.
文摘The blue-emitting YPO4 phosphors doped with Yb3+ were prepared by a simple hydrothermal method. All the products were characterized by XRD and TEM, which revealed that they were zircon structure with leaf-like morphology. According to the analysis of photoluminescence spectra, upon ultraviolet (275 nm) excitation, the Yb3+ doped YPO4 phosphor showed an intense blue emission composed of two main bands at 420 and 620 nm assigned to charge transfer state (CTS) → 2Fs/2 and CTS →ZF7/2, respectively. Moreover, the optimum doping concentration of Yb3+ in YPO4 phosphor was 1%, which exhibited the maximum emission intensity. The possible physical mechanism of concentration quenching was discussed, and the critical transfer distance determined to be 23.889 A. In particular, the color purity of the as-synthesized Yb3+ doped YPO4 phosphor was as high as 83%, which made it an excellent candidate for blue-emitting materials.
基金This work was supported by the Research Topic "Research on the Injury Mechanism of Complex Craniocerebral Injuries and the Comprehensive Diagnosis Methods of Forensic Medicine"(2018YFC0807203)under Project"Research on the Basic Theory of Forensic Medicine and Trace Inspection Science" of 2018 National Key R&D Program of China and was a Funded Project of Fundamental Research Funds for the Central Scientific Research Institutes(2016JB041).
文摘The role of computed tomography(CT)images in forensic identification has been widely recognized.Such images can provide an important basis for identification of the cause of death in complicated and difficult cases,including falls from a height,drowning,explosion and gunshot cases,traffic accidents,and sudden death.However,few reports have focused on the application of CT images in cases of death caused by sharp object injuries.Therefore,the CT images and autopsy findings were compared in a case of death caused by sharp object injuries to the chest and abdomen,and the importance of CT images in cases of death from common sharp object injuries is herein discussed.