With the increasing number of airports and the expansion of their scale,the aviation network has become complex and hierarchical.In order to investigate the complex network characteristics of aviation networks,this pa...With the increasing number of airports and the expansion of their scale,the aviation network has become complex and hierarchical.In order to investigate the complex network characteristics of aviation networks,this paper constructs a Chinese aviation network model and carries out related research based on complex network theory and K-means algorithm.Initially,the P-space model is employed to construct the Chinese aviation network model.Then,complex network indicators such as degree,clustering coefficient,average path length,betweenness and coreness are selected to investigate the complex characteristics and hierarchical features of aviation networks and explore their causes.Secondly,using K-means clustering algorithm,five values are obtained as the initial clustering parameter K values for each of the aviation network hierarchies classified according to five complex network indicators.Meanwhile,clustering simulation experiments are conducted to obtain the visual clustering results of Chinese aviation network nodes under different K values,as well as silhouette coefficients for evaluating the clustering effect of each indicator in order to obtain the hierarchical classification of aviation networks under different indicators.Finally,the silhouette coefficient is optimal when the K value is 4.Thus,the clustering results of the four layers of the aviation network can be obtained.According to the experimental results,the complex network association discovery method combined with K-means algorithm has better applicability and simplicity,while the accuracy is improved.展开更多
In recent years,QR code has been widely used in the Internet and mobile devices.It is based on open standards and easy to generate a code,which lead to that anyone can generate their own QR code.Because the QR code do...In recent years,QR code has been widely used in the Internet and mobile devices.It is based on open standards and easy to generate a code,which lead to that anyone can generate their own QR code.Because the QR code does not have the ability of information hiding,any device can access the content in QR code.Thus,hiding the secret data in QR code becomes a hot topic.Previously,the information hiding methods based on QR code all use the way of information hiding based on image,mostly using digital watermarking technology,and not using the coding rules of QR code to hide information.Therefore,we propose a distributed information sharing method based on QR code information hiding.On the one hand,we can start from the coding rules of QR code and use the information hiding method to maximize the capacity of secret information embedded in QR code.On the other hand,the distributed information sharing method is used to decentralize.At the same time,experimental results and analysis show that the proposed scheme can prevent the attack of camouflage attacker,and finally recover hidden information by secret reconstruction.展开更多
The chiral phosphoric acid catalyst enables the atroposelective arylation of 5-aminoisoxazoles and quinones by accelerating the kinetics of the enantioselective catalytic reaction, effectively outcompeting and even su...The chiral phosphoric acid catalyst enables the atroposelective arylation of 5-aminoisoxazoles and quinones by accelerating the kinetics of the enantioselective catalytic reaction, effectively outcompeting and even suppressing the uncatalyzed racemic background reaction. In this strategy, a large panel of axially chiral isoxazole-derived amino alcohols was synthesized with generally high yields and excellent enantioselectivities. The method features mild reaction conditions, broad functional group compatibility and good scalability. X-ray crystallography and thermal racemization experiments revealed the important role of six-membered intramolecular O?H···O hydrogen bonding in stabilizing the configurations, which exhibit markedly different racemization barriers in protic and aprotic solvents. Moreover, preliminary mechanistic studies, including nonlinear effects and control experiments were conducted to elucidate the reaction mechanism and activation mode. This approach not only provides an efficient method for constructing pentatomic isoxazole scaffolds, but also expands the family of axially chiral amino alcohols.展开更多
Foxtail millet(Setaria italica),a vital drought-resistant crop,plays a significant role in ensuring food and nutritional security.However,its drought resistance mechanism is not fully understood.N6-methyladenosine(m^(...Foxtail millet(Setaria italica),a vital drought-resistant crop,plays a significant role in ensuring food and nutritional security.However,its drought resistance mechanism is not fully understood.N6-methyladenosine(m^(6)A)modification of RNA,a prevalent epi-transcriptomic modification in eukaryotes,provides a binding site for m^(6)A readers and affects plant growth and stress responses by regulating RNA metabolism.In this study,we unveiled that the YT521-B homology(YTH)family gene SiYTH1 positively regulated the drought tolerance of foxtail millet.Notably,the siyth1 mutant exhibited reduced stomatal closure and augmented accumulation of excessive H_(2)O_(2)under drought stress.Further investigations demonstrated that SiYTH1 positively regulated the transcripts harboring m^(6)A modification related to stomatal closure and reactive oxygen species(ROS)scavenging under drought stress.SiYTH1 was uniformly distributed in the cytoplasm of SiYTH1-GFP transgenic foxtail millet.It formed dynamic liquid-like SiYTH1 cytosol condensates in response to drought stress.Moreover,the cytoplasmic protein SiYTH1 was identified as a distinct m^(6)A reader,facilitating the stabilization of its directly bound SiARDP and ROS scavenging-related transcripts under drought stress.Furthermore,natural variation analysis revealed SiYTH1AGTG as the dominant allele responsible for drought tolerance in foxtail millet.Collectively,this study provides novel insights into the intricate mechanism of m^(6)A reader-mediated drought tolerance and presents a valuable genetic resource for improving drought tolerance in foxtail millet breeding.展开更多
DNA sequencers have become increasingly important research and diagnostic tools over the past 20 years.In this study,we developed a single-molecule desktop sequencer,GenoCare 1600(GenoCare),which utilizes amplificatio...DNA sequencers have become increasingly important research and diagnostic tools over the past 20 years.In this study,we developed a single-molecule desktop sequencer,GenoCare 1600(GenoCare),which utilizes amplification-free library preparation and two-color sequencing-by-synthesis chemistry,making it more user-friendly compared with previous single-molecule sequencing platforms for clinical use.Using the GenoCare platform,we sequenced an Escherichia coli standard sample and achieved a consensus accuracy exceeding 99.99%.We also evaluated the sequencing performance of this platform in microbial mixtures and coronavirus disease 2019(COVID-19)samples from throat swabs.Our findings indicate that the GenoCare platform allows for microbial quantitation,sensitive identification of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)virus,and accurate detection of virus mutations,as confirmed by Sanger sequencing,demonstrating its remarkable potential in clinical application.展开更多
文摘With the increasing number of airports and the expansion of their scale,the aviation network has become complex and hierarchical.In order to investigate the complex network characteristics of aviation networks,this paper constructs a Chinese aviation network model and carries out related research based on complex network theory and K-means algorithm.Initially,the P-space model is employed to construct the Chinese aviation network model.Then,complex network indicators such as degree,clustering coefficient,average path length,betweenness and coreness are selected to investigate the complex characteristics and hierarchical features of aviation networks and explore their causes.Secondly,using K-means clustering algorithm,five values are obtained as the initial clustering parameter K values for each of the aviation network hierarchies classified according to five complex network indicators.Meanwhile,clustering simulation experiments are conducted to obtain the visual clustering results of Chinese aviation network nodes under different K values,as well as silhouette coefficients for evaluating the clustering effect of each indicator in order to obtain the hierarchical classification of aviation networks under different indicators.Finally,the silhouette coefficient is optimal when the K value is 4.Thus,the clustering results of the four layers of the aviation network can be obtained.According to the experimental results,the complex network association discovery method combined with K-means algorithm has better applicability and simplicity,while the accuracy is improved.
文摘In recent years,QR code has been widely used in the Internet and mobile devices.It is based on open standards and easy to generate a code,which lead to that anyone can generate their own QR code.Because the QR code does not have the ability of information hiding,any device can access the content in QR code.Thus,hiding the secret data in QR code becomes a hot topic.Previously,the information hiding methods based on QR code all use the way of information hiding based on image,mostly using digital watermarking technology,and not using the coding rules of QR code to hide information.Therefore,we propose a distributed information sharing method based on QR code information hiding.On the one hand,we can start from the coding rules of QR code and use the information hiding method to maximize the capacity of secret information embedded in QR code.On the other hand,the distributed information sharing method is used to decentralize.At the same time,experimental results and analysis show that the proposed scheme can prevent the attack of camouflage attacker,and finally recover hidden information by secret reconstruction.
基金the financial support from the National Natural Science Foundation of China(22201022)Hunan Provincial Natural Science Foundation of China(2024JJ5011).Our gratitude goes out to Dr.Xueying Qiu and Zhi-Wei Li from the Analytical and Testing Center of Changsha University of Science and Technology for their assistance with NMR spectrum analysis and HRMS.
文摘The chiral phosphoric acid catalyst enables the atroposelective arylation of 5-aminoisoxazoles and quinones by accelerating the kinetics of the enantioselective catalytic reaction, effectively outcompeting and even suppressing the uncatalyzed racemic background reaction. In this strategy, a large panel of axially chiral isoxazole-derived amino alcohols was synthesized with generally high yields and excellent enantioselectivities. The method features mild reaction conditions, broad functional group compatibility and good scalability. X-ray crystallography and thermal racemization experiments revealed the important role of six-membered intramolecular O?H···O hydrogen bonding in stabilizing the configurations, which exhibit markedly different racemization barriers in protic and aprotic solvents. Moreover, preliminary mechanistic studies, including nonlinear effects and control experiments were conducted to elucidate the reaction mechanism and activation mode. This approach not only provides an efficient method for constructing pentatomic isoxazole scaffolds, but also expands the family of axially chiral amino alcohols.
基金This work was supported by the National Key R&D Program of China(2023YFD1200700/2023YFD1200702/2018YFD1000700/2018YFD1000704).
文摘Foxtail millet(Setaria italica),a vital drought-resistant crop,plays a significant role in ensuring food and nutritional security.However,its drought resistance mechanism is not fully understood.N6-methyladenosine(m^(6)A)modification of RNA,a prevalent epi-transcriptomic modification in eukaryotes,provides a binding site for m^(6)A readers and affects plant growth and stress responses by regulating RNA metabolism.In this study,we unveiled that the YT521-B homology(YTH)family gene SiYTH1 positively regulated the drought tolerance of foxtail millet.Notably,the siyth1 mutant exhibited reduced stomatal closure and augmented accumulation of excessive H_(2)O_(2)under drought stress.Further investigations demonstrated that SiYTH1 positively regulated the transcripts harboring m^(6)A modification related to stomatal closure and reactive oxygen species(ROS)scavenging under drought stress.SiYTH1 was uniformly distributed in the cytoplasm of SiYTH1-GFP transgenic foxtail millet.It formed dynamic liquid-like SiYTH1 cytosol condensates in response to drought stress.Moreover,the cytoplasmic protein SiYTH1 was identified as a distinct m^(6)A reader,facilitating the stabilization of its directly bound SiARDP and ROS scavenging-related transcripts under drought stress.Furthermore,natural variation analysis revealed SiYTH1AGTG as the dominant allele responsible for drought tolerance in foxtail millet.Collectively,this study provides novel insights into the intricate mechanism of m^(6)A reader-mediated drought tolerance and presents a valuable genetic resource for improving drought tolerance in foxtail millet breeding.
文摘DNA sequencers have become increasingly important research and diagnostic tools over the past 20 years.In this study,we developed a single-molecule desktop sequencer,GenoCare 1600(GenoCare),which utilizes amplification-free library preparation and two-color sequencing-by-synthesis chemistry,making it more user-friendly compared with previous single-molecule sequencing platforms for clinical use.Using the GenoCare platform,we sequenced an Escherichia coli standard sample and achieved a consensus accuracy exceeding 99.99%.We also evaluated the sequencing performance of this platform in microbial mixtures and coronavirus disease 2019(COVID-19)samples from throat swabs.Our findings indicate that the GenoCare platform allows for microbial quantitation,sensitive identification of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)virus,and accurate detection of virus mutations,as confirmed by Sanger sequencing,demonstrating its remarkable potential in clinical application.
