G protein coupled receptor kinase 2 (GRK2) is a kinase that regulates cardiac signaling activity. Inhibiting GRK2 is a promising mechanism for the treatment of heart failure (HF). Further development and optimization ...G protein coupled receptor kinase 2 (GRK2) is a kinase that regulates cardiac signaling activity. Inhibiting GRK2 is a promising mechanism for the treatment of heart failure (HF). Further development and optimization of inhibitors targeting GRK2 are highly meaningful. Therefore, in order to design GRK2 inhibitors with better performance, the most active molecule was selected as a reference compound from a data set containing 4-pyridylhydrazone derivatives and triazole derivatives, and its scaffold was extracted as the initial scaffold. Then, a powerful optimization-based framework for de novo drug design, guided by binding affinity, was used to generate a virtual molecular library targeting GRK2. The binding affinity of each virtual compound in this dataset was predicted by our developed deep learning model, and the designed potential compound with high binding affinity was selected for molecular docking and molecular dynamics simulation. It was found that the designed potential molecule binds to the ATP site of GRK2, which consists of key amino acids including Arg199, Gly200, Phe202, Val205, Lys220, Met274 and Asp335. The scaffold of the molecule is stabilized mainly by H-bonding and hydrophobic contacts. Concurrently, the reference compound in the dataset was also simulated by docking. It was found that this molecule also binds to the ATP site of GRK2. In addition, its scaffold is stabilized mainly by H-bonding and π-cation stacking interactions with Lys220, as well as hydrophobic contacts. The above results show that the designed potential molecule has similar binding modes to the reference compound, supporting the effectiveness of our framework for activity-focused molecular design. Finally, we summarized the interaction characteristics of general GRK2 inhibitors and gained insight into their molecule-target binding mechanisms, thereby facilitating the expansion of lead to hit compound.展开更多
During the sizing process,yarn congestion fault occurs at the reed teeth of a sizing machine.At present,the yarn congestion fault is generally handled by manual detection.The sizing production line operates on a large...During the sizing process,yarn congestion fault occurs at the reed teeth of a sizing machine.At present,the yarn congestion fault is generally handled by manual detection.The sizing production line operates on a large scale and runs continuously.Untimely handling of the yarn congestion fault causes a large amount of yarn waste.In this research,a machine vision-based algorithm for yarn congestion fault detection is developed.Through the analysis of the congestion fault and interference contour characteristics,the basic idea of image phase subtraction to identify the congestion fault is determined.To address the interference information appearing after image phase subtraction,the image pre-processing methods of Canny edge extraction and mean filtering are employed.According to the fault size and location characteristics,the fault contour detection algorithm based on inter-frame difference is designed.To mitigate the camera vibration interference,the anti-vibration interference algorithm based on affine transformation is studied,and the fault detection algorithm for the total yarn congestion fault is determined.The detection of 20 sets of field data is carried out,and the detection rate reaches 90%.This fault detection algorithm realizes the automatic detection of yarn congestion fault of sizing machine with certain real-time performance and accuracy.展开更多
The ecological and evolutionary mechanisms underlying montane biodiversity patterns remain unresolved.To understand which factors determined community assembly rules in mountains,biogeographic affinity that represents...The ecological and evolutionary mechanisms underlying montane biodiversity patterns remain unresolved.To understand which factors determined community assembly rules in mountains,biogeographic affinity that represents the biogeographic and evolutionary history of species should incorporate with current environments.We aim to address two following questions:1)How does plant taxonomic and phylogenetic diversity with disparate biogeographic affinitiesvary along the subtropical elevational gradient?2)How do biogeographic affinityand environmental drivers regulate the community assembly?We collected woody plant survey data of 32 forest plots in a subtropical mountain of Mt.Guanshan with typical transitional characteristics,including 250 woody plant species belonging to 56 families and 118 genera.We estimated the effects of biogeographic affinity,climate and soil properties on taxonomic and phylogenetic diversity of plant communities employing linear regression and structural equation models.We found that the richness of temperate-affiliated species increased with elevations,but the evenness decreased,while tropical-affiliatedspecies had no significantpatterns.Winter temperature directly or indirectly via biogeographic affinityshaped the assemblage of woody plant communities along elevations.Biogeographic affinityaffected what kind of species could colonize higher elevations while local environment determined their fitnessto adapt.These results suggest that biogeographic affinityand local environment jointly lead to the dominance of temperate-affiliated species at higher elevations and shape the diversity of woody plant communities along elevational gradients.Our findingshighlight the legacy effect of biogeographic affinityon the composition and structure of subtropical montane forests.展开更多
The ion coordination affinities of the commonly found metal ions were evaluated using DFT calculations.The results indicate that the lowest unoccupied molecular orbital(LUMO)energy of metal ions correlates positively ...The ion coordination affinities of the commonly found metal ions were evaluated using DFT calculations.The results indicate that the lowest unoccupied molecular orbital(LUMO)energy of metal ions correlates positively with their binding energies with O(S)ligands,and some metal ions with various valence states also present different affinities.Besides,due to the steric hindrance effects,the mono-and hexa-coordinated metal ions may exhibit different affinities,and the majority of the studied hexa-coordinated metal ions exhibit oxophilicity.These affinity differences perfectly illustrate the activation flotation practice in which the oxyphilic ions are applied to activating oxide minerals,while thiophilic ions are applied to activating sulfide minerals.展开更多
The paper presents a two-layer,disturbance-resistant,and fault-tolerant affine formation maneuver control scheme that accomplishes the surrounding of a dynamic target with multiple underactuated Quadrotor Unmanned Aer...The paper presents a two-layer,disturbance-resistant,and fault-tolerant affine formation maneuver control scheme that accomplishes the surrounding of a dynamic target with multiple underactuated Quadrotor Unmanned Aerial Vehicles(QUAVs).This scheme mainly consists of predefinedtime estimators and fixed-time tracking controllers,with a hybrid Laplacian matrix describing the communication among these QUAVs.At the first layer,we devise predefined time estimators for leading and following QUAVs,enabling accurate estimation of desired information.In the second layer,we initially devise a fixed-time hybrid observer to estimate unknown disturbances and actuator faults.Fixedtime translational tracking controllers are then proposed,and the intermediary control input from these controllers is used to extract the desired attitude and angular velocities for the fixed-time rotational tracking controllers.We employ an exact tracking differentiator to handle variables that are challenging to differentiate directly.The paper includes a demonstration of the control system stability through mathematical proof,as well as the presentation of simulation results and comparative simulations.展开更多
Sini Decoction(SNT)is a traditional formula recognized for its efficacy in warming the spleen and stomach and dispersing cold.However,elucidating the mechanism of action of SNT remains challenging due to its complex m...Sini Decoction(SNT)is a traditional formula recognized for its efficacy in warming the spleen and stomach and dispersing cold.However,elucidating the mechanism of action of SNT remains challenging due to its complex multiple components.This study utilized a synergistic approach combining two-dimensional fluorescence difference in gel electrophoresis(2D-DIGE)-based drug affinity responsive target stability(DARTS)with label-free quantitative proteomics techniques to identify the direct and indirect protein targets of SNT in myocardial infarction.The analysis identified 590 proteins,with 30 proteins showing significant upregulation and 51 proteins showing downregulation when comparing the SNT group with the model group.Through the integration of 2D-DIGE DARTS with proteomics data and pharmacological assessments,the findings indicate that protein disulfide-isomerase A3(PDIA3)may serve as a potential protein target through which SNT provides protective effects on myocardial cells during myocardial infarction.展开更多
纽结理论是拓扑学的一个重要分支,虚拟纽结理论是经典纽结理论的推广,对它的研究是通过一种图解理论来展开的。虚拟纽结多项式是一类以多项式表达的虚拟纽结不变量,例如Arrow多项式和Wriggle多项式。Affine index多项式是以虚拟纽结图...纽结理论是拓扑学的一个重要分支,虚拟纽结理论是经典纽结理论的推广,对它的研究是通过一种图解理论来展开的。虚拟纽结多项式是一类以多项式表达的虚拟纽结不变量,例如Arrow多项式和Wriggle多项式。Affine index多项式是以虚拟纽结图的整数标记定义的单变量多项式。本文主要计算一类特殊虚拟纽结的Affine index多项式。按照Cheng着色的规则,对虚拟纽结图的每一段弧进行整数标记,计算每个经典交叉点的指标值,进而得到这类特殊虚拟纽结的Affine index多项式的表达式。Knot theory is an important branch of topology. Virtual knot theory is a generalization of classical knot theory, and its research is carried out through a graphic theory. The virtual knot polynomial refers to a class of virtual knot invariant expressed by polynomials, such as the Arrow polynomial and the Wriggle polynomial. The affine index polynomial is a univariate polynomial defined by the integer label of a virtual knot graph. In this paper, we mainly calculate affine index polynomials for a special class of virtual knots. According to the rules of Cheng coloring, we will integer label each arc of the virtual knot graph and calculate the index value of each classical crossings, and then get the expression of the affine index polynomial of this special virtual knot.展开更多
Objective:Salvia miltiorrhiza is widely used in traditional Chinese medicine for treating cardiovascular and cerebrovascular diseases,with tanshinones being its major active components.This study aims to systematicall...Objective:Salvia miltiorrhiza is widely used in traditional Chinese medicine for treating cardiovascular and cerebrovascular diseases,with tanshinones being its major active components.This study aims to systematically elucidate the core transcriptional circuitry controlling tanshinone production,thereby establishing a mechanistic framework to optimize phytochemical yield and advance sustainable cultivation strategies for this pharmaceutically vital species.Methods:Transcriptome profiling revealed that the transcription factor SmWRKY69 is specifically expressed in the root periderm of S.miltiorrhiza.DNA affinity purification sequencing(DAPseq)was used to identify its potential target genes,and cis-element analysis predicted W-box motifs in the promoters of SmCPS1 and SmKSL1.Yeast one-hybrid(Y1H)assays were employed to validate its regulatory interactions with candidate gene promoters.Results:SmWRKY69 was found to directly bind to the promoters of SmCPS1 and SmKSL1,key genes in the tanshinone biosynthetic pathway,through W-box elements,indicating its role as a transcriptional regulator.Conclusion:SmWRKY69 regulates tanshinone biosynthesis by directly targeting SmCPS1 and SmKSL1,providing a valuable genetic target for metabolic engineering to enhance the therapeutic quality of S.miltiorrhiza.展开更多
In this article,we explain how the famous Archimedes’principle of flotation can be used to construct various floating bodies.We survey some of the most important results regarding the floating bodies,including their ...In this article,we explain how the famous Archimedes’principle of flotation can be used to construct various floating bodies.We survey some of the most important results regarding the floating bodies,including their relations with affine surface area and projection body,their extensions in different settings such as space forms and log-concave functions,and mention some associated open problems.展开更多
Excessive Fe^(3+) ion concentrations in wastewater pose a long-standing threat to human health.Achieving low-cost,high-efficiency quantification of Fe^(3+) ion concentration in unknown solutions can guide environmenta...Excessive Fe^(3+) ion concentrations in wastewater pose a long-standing threat to human health.Achieving low-cost,high-efficiency quantification of Fe^(3+) ion concentration in unknown solutions can guide environmental management decisions and optimize water treatment processes.In this study,by leveraging the rapid,real-time detection capabilities of nanopores and the specific chemical binding affinity of tannic acid to Fe^(3+),a linear relationship between the ion current and Fe^(3+) ion concentration was established.Utilizing this linear relationship,quantification of Fe^(3+) ion concentration in unknown solutions was achieved.Furthermore,ethylenediaminetetraacetic acid disodium salt was employed to displace Fe^(3+) from the nanopores,allowing them to be restored to their initial conditions and reused for Fe^(3+) ion quantification.The reusable bioinspired nanopores remain functional over 330 days of storage.This recycling capability and the long-term stability of the nanopores contribute to a significant reduction in costs.This study provides a strategy for the quantification of unknown Fe^(3+) concentration using nanopores,with potential applications in environmental assessment,health monitoring,and so forth.展开更多
In this paper,we shall study structures of even lattice vertex operator algebras by using the geometry of the varieties of their semi-conformal vectors.We first give the varieties of semi-conformal vectors of a family...In this paper,we shall study structures of even lattice vertex operator algebras by using the geometry of the varieties of their semi-conformal vectors.We first give the varieties of semi-conformal vectors of a family of vertex operator algebras V_(√kA_(1)) associated to rank-one positive definite even lattices √kA_(1) for arbitrary positive integers k to characterize these even lattice vertex operator algebras.In such a family of lattice vertex operator algebras V_(√kA_(1)),the vertex operator algebra V_(√2A_(1)) is different from others.Hence we describe the varieties of semi-conformal vectors of V_(√2A_(1)) and the fixed vertex operator subalgebra V^(+)√2A_(1).Moreover,as applications,we study the relations between vertex operator algebras V_(√kA_(1) )and L_(sl_(2))(k,0)for arbitrary positive integers k by the viewpoint of semi-conformal homomorphisms of vertex operator algebras.For case k=2,in the series of rational simple affine vertex operator algebras L_(sl_(2))(k,0)for positive integers k,we show that L_(sl_(2))(2,0)is a unique frame vertex operator algebra with rank 3.展开更多
The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships ...The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships between image pairs.Methods based on geometric transformation estimation usually perform affine transformation of the global image for viewpoint correction,which not only increases the time complexity but also generates a large number of redundant features.To solve this problem,this paper proposes an adaptive affine transformation model(AATM)to achieve robust image matching by dividing special regions with pixel information and employing feature extraction algorithms with different granularities.First,the input image is divided into significant and non-significant regions by an adaptive algorithm.Second,for the salient region,the feature point extraction is accelerated by optimizing the longitude angle sampling algorithm and constructing the affine invariant nonlinear scale space,introducing the Hessian integral image and box filter.Then,for the non-significant region of the weak texture scene through the uniform step sampling algorithm,a dense feature description can be obtained in the weak texture scenes,so that more robust features are extracted for both significant and non-significant regions.The results of extensive experiments on two datasets show that the AATM algorithm outperforms similar algorithms in terms of the number of correctly matched pairs,elapsed time,and root mean square error(RMSE),indicating that the AATM can obtain more robust matches in scenes with large angle tilting and scale transformations.展开更多
Artificial intelligence(AI)researchers and cheminformatics specialists strive to identify effective drug precursors while optimizing costs and accelerating development processes.Digital molecular representation plays ...Artificial intelligence(AI)researchers and cheminformatics specialists strive to identify effective drug precursors while optimizing costs and accelerating development processes.Digital molecular representation plays a crucial role in achieving this objective by making molecules machine-readable,thereby enhancing the accuracy of molecular prediction tasks and facilitating evidence-based decision making.This study presents a comprehensive review of small molecular representations and AI-driven drug discovery downstream tasks utilizing these representations.The research methodology begins with the compilation of small molecule databases,followed by an analysis of fundamental molecular representations and the models that learn these representations from initial forms,capturing patterns and salient features across extensive chemical spaces.The study then examines various drug discovery downstream tasks,including drug-target interaction(DTI)prediction,drug-target affinity(DTA)prediction,drug property(DP)prediction,and drug generation,all based on learned representations.The analysis concludes by highlighting challenges and opportunities associated with machine learning(ML)methods for molecular representation and improving downstream task performance.Additionally,the representation of small molecules and AI-based downstream tasks demonstrates significant potential in identifying traditional Chinese medicine(TCM)medicinal substances and facilitating TCM target discovery.展开更多
Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent N...Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.展开更多
In addition to the electron transfer,the appropriate H-adsorption affinity of active centers on the metal cocatalyst surface is quite important for high hydrogen-production activity of cocatalyst-modified photo-cataly...In addition to the electron transfer,the appropriate H-adsorption affinity of active centers on the metal cocatalyst surface is quite important for high hydrogen-production activity of cocatalyst-modified photo-catalysts.The typical Cu and Ru metal cocatalysts clearly exhibit a weak Cu-H bond and a strong Ru-H bond,respectively,resulting in limited activity for photocatalytic H_(2)evolution.In this work,an ingenious strategy of self-optimized H-adsorption affinity in CuRu alloy cocatalyst is developed to simultaneously reinforce the Cu-H bond and weaken the Ru-H bond by the intrinsic electron transfer from Cu to Ru atom.The CuRu alloy nanoparticles(2-3 nm)were deposited on the TiO_(2)surface to prepare CuRu/TiO_(2)through a one-step photoreduction method.Photocatalytic tests exhibited that the highest H_(2)-production rate of CuRu/TiO_(2)photocatalyst reached up to 5.316 mmol h^(-1)g^(-1),which was 24.80,1.86,and 2.60 times higher than that of the TiO_(2),Cu/TiO_(2),and Ru/TiO_(2),respectively.Based on the characterization results and theoretical calculations,the CuRu alloy cocatalyst exhibits excellent self-optimized H-adsorption affinity via the spontaneous electron transfer from Cu to Ru atom,which can greatly accelerate the photocatalytic H_(2)-production rate of TiO_(2).This work provides a feasible idea for the self-optimized H-adsorption affinity of metal active sites in the photocatalytic H_(2)-generation field.展开更多
In this paper,we compute sub-Riemannian limits of Gaussian curvature associated to two kinds of Schouten-Van Kampen affine connections and the adapted connection for a Euclidean C2-smooth surface in the Heisenberg gro...In this paper,we compute sub-Riemannian limits of Gaussian curvature associated to two kinds of Schouten-Van Kampen affine connections and the adapted connection for a Euclidean C2-smooth surface in the Heisenberg group away from characteristic points and signed geodesic curvature associated to two kinds of Schouten-Van Kampen affine connections and the adapted connection for Euclidean C2-smooth curves on surfaces.We get Gauss-Bonnet theorems associated to two kinds of Schouten-Van Kampen affine connections in the Heisenberg group.展开更多
Nitrification,a central process in the marine nitrogen cycle,produces regenerated nitrate in the euphotic zone and emits N_(2)O,a potent greenhouse gas as a by-product.The regulatory mechanisms of nitrification in the...Nitrification,a central process in the marine nitrogen cycle,produces regenerated nitrate in the euphotic zone and emits N_(2)O,a potent greenhouse gas as a by-product.The regulatory mechanisms of nitrification in the Southern Ocean,which is a critical region for CO_(2)sequestration and radiative benefits,remain poorly understood.Here,we investigated the in situ and dark nitrification rates in the upper 500 m and conducted substrate kinetics experiments across the Indian Sector in the Cosmonaut and Cooperation seas in the late austral summer.Our findings indicate that light inhibition of nitrification decreases exponentially with depth,exhibiting a light threshold of 0.53%photosynthetically active radiation.A positive relationship between dark nitrification and apparent oxygen utilization suggests a dependence on substrate availability from primary production.Importantly,an increased NH_(4)^(+) supply can act as a buffer against photo-inhibitory damage.Globally,substrate affinity(α)increases with depth and transitions from light to dark,decreases with increasing ambient NH_(4)^(+)and exhibits a latitudinal distribution,reflecting substrate utilization strategies.We also reveal that upwelling in Circumpolar Deep Water(CDW)stimulates nitrification through the introduction of potentially higher iron and deep diverse nitrifying microorganisms with higherα.We conclude that although light is the primary limiting factor for nitrification in summer,coupling between substrate availability and CDW upwelling can overcome this limitation,thereby alleviating photoinhibition by up to 45%±5.3%.展开更多
[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under c...[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under challenging conditions,such as strong light exposure and weed interference.The aims are to develop an effective crop line extraction method by combining YOLOv8-G,Affinity Propagation,and the Least Squares method to enhance detection accuracy and performance in complex field environments.[Methods]The proposed method employs machine vision techniques to address common field challenges.YOLOv8-G,an improved object detection algorithm that combines YOLOv8 and Ghost‐NetV2 for lightweight,high-speed performance,was used to detect the central points of crops.These points were then clustered using the Affinity Propagation algorithm,followed by the application of the Least Squares method to extract the crop lines.Comparative tests were conducted to evaluate multiple backbone networks within the YOLOv8 framework,and ablation studies were performed to validate the enhancements made in YOLOv8-G.[Results and Discussions]The performance of the proposed method was compared with classical object detection and clustering algorithms.The YOLOv8-G algorithm achieved average precision(AP)values of 98.22%,98.15%,and 97.32%for corn detection at 7,14,and 21 days after emergence,respectively.Additionally,the crop line extraction accuracy across all stages was 96.52%.These results demonstrate the model's ability to maintain high detection accuracy despite challenging conditions in the field.[Conclusions]The proposed crop line extraction method effectively addresses field challenges such as lighting and weed interference,enabling rapid and accurate crop identification.This approach supports the automatic navigation of agricultural machinery,offering significant improvements in the precision and efficiency of field operations.展开更多
基金supported by the National Natural Science Foundation of China Excellent Young Scientist Fund(22422801)the National Natural Science Foundation of China General Project(22278053)+1 种基金the National Natural Science Foundation of China General Project(22078041)Dalian High-level Talents Innovation Support Program(2023RQ059).
文摘G protein coupled receptor kinase 2 (GRK2) is a kinase that regulates cardiac signaling activity. Inhibiting GRK2 is a promising mechanism for the treatment of heart failure (HF). Further development and optimization of inhibitors targeting GRK2 are highly meaningful. Therefore, in order to design GRK2 inhibitors with better performance, the most active molecule was selected as a reference compound from a data set containing 4-pyridylhydrazone derivatives and triazole derivatives, and its scaffold was extracted as the initial scaffold. Then, a powerful optimization-based framework for de novo drug design, guided by binding affinity, was used to generate a virtual molecular library targeting GRK2. The binding affinity of each virtual compound in this dataset was predicted by our developed deep learning model, and the designed potential compound with high binding affinity was selected for molecular docking and molecular dynamics simulation. It was found that the designed potential molecule binds to the ATP site of GRK2, which consists of key amino acids including Arg199, Gly200, Phe202, Val205, Lys220, Met274 and Asp335. The scaffold of the molecule is stabilized mainly by H-bonding and hydrophobic contacts. Concurrently, the reference compound in the dataset was also simulated by docking. It was found that this molecule also binds to the ATP site of GRK2. In addition, its scaffold is stabilized mainly by H-bonding and π-cation stacking interactions with Lys220, as well as hydrophobic contacts. The above results show that the designed potential molecule has similar binding modes to the reference compound, supporting the effectiveness of our framework for activity-focused molecular design. Finally, we summarized the interaction characteristics of general GRK2 inhibitors and gained insight into their molecule-target binding mechanisms, thereby facilitating the expansion of lead to hit compound.
基金National Key Research and Development Program of China(No.2017YFB1304001)。
文摘During the sizing process,yarn congestion fault occurs at the reed teeth of a sizing machine.At present,the yarn congestion fault is generally handled by manual detection.The sizing production line operates on a large scale and runs continuously.Untimely handling of the yarn congestion fault causes a large amount of yarn waste.In this research,a machine vision-based algorithm for yarn congestion fault detection is developed.Through the analysis of the congestion fault and interference contour characteristics,the basic idea of image phase subtraction to identify the congestion fault is determined.To address the interference information appearing after image phase subtraction,the image pre-processing methods of Canny edge extraction and mean filtering are employed.According to the fault size and location characteristics,the fault contour detection algorithm based on inter-frame difference is designed.To mitigate the camera vibration interference,the anti-vibration interference algorithm based on affine transformation is studied,and the fault detection algorithm for the total yarn congestion fault is determined.The detection of 20 sets of field data is carried out,and the detection rate reaches 90%.This fault detection algorithm realizes the automatic detection of yarn congestion fault of sizing machine with certain real-time performance and accuracy.
基金financialsupport from the Jiangxi Natural Science Foundation(20242BAB25345)to Z.Z.the Innovation Program of Shanghai Municipal Education Commission(2023ZKZD36)to J.Z.
文摘The ecological and evolutionary mechanisms underlying montane biodiversity patterns remain unresolved.To understand which factors determined community assembly rules in mountains,biogeographic affinity that represents the biogeographic and evolutionary history of species should incorporate with current environments.We aim to address two following questions:1)How does plant taxonomic and phylogenetic diversity with disparate biogeographic affinitiesvary along the subtropical elevational gradient?2)How do biogeographic affinityand environmental drivers regulate the community assembly?We collected woody plant survey data of 32 forest plots in a subtropical mountain of Mt.Guanshan with typical transitional characteristics,including 250 woody plant species belonging to 56 families and 118 genera.We estimated the effects of biogeographic affinity,climate and soil properties on taxonomic and phylogenetic diversity of plant communities employing linear regression and structural equation models.We found that the richness of temperate-affiliated species increased with elevations,but the evenness decreased,while tropical-affiliatedspecies had no significantpatterns.Winter temperature directly or indirectly via biogeographic affinityshaped the assemblage of woody plant communities along elevations.Biogeographic affinityaffected what kind of species could colonize higher elevations while local environment determined their fitnessto adapt.These results suggest that biogeographic affinityand local environment jointly lead to the dominance of temperate-affiliated species at higher elevations and shape the diversity of woody plant communities along elevational gradients.Our findingshighlight the legacy effect of biogeographic affinityon the composition and structure of subtropical montane forests.
基金financially supported by the National Natural Science Foundation of China(Nos.52074356,U20A20269)the Key Technology Research and Development Program,China(No.2022YFC2904503)+4 种基金the Special Fund for the Construction of Hunan Province,China(No.2023SK2061)the Science and Technology Innovation Program of Hunan Province,China(No.2022RC1183)the Changsha Science and Technology Project(Changsha Outstanding Innovative Youth Training Program),ChinaInnovation-driven Project of Central South University,China(No.2023CXQD002)Higher Education Discipline Innovation Project,China(No.B14034)。
文摘The ion coordination affinities of the commonly found metal ions were evaluated using DFT calculations.The results indicate that the lowest unoccupied molecular orbital(LUMO)energy of metal ions correlates positively with their binding energies with O(S)ligands,and some metal ions with various valence states also present different affinities.Besides,due to the steric hindrance effects,the mono-and hexa-coordinated metal ions may exhibit different affinities,and the majority of the studied hexa-coordinated metal ions exhibit oxophilicity.These affinity differences perfectly illustrate the activation flotation practice in which the oxyphilic ions are applied to activating oxide minerals,while thiophilic ions are applied to activating sulfide minerals.
基金supported by Natural Science Basic Research Plan in Shaanxi Province of China(No.2023-JC-QN-0733)Guangdong Basic and Applied Basic Research Foundation,China(No.2022A1515110753)+2 种基金China Postdoctoral Science Foundation(No.2022M722583)China Industry-UniversityResearch Innovation Foundation(No.2022IT188)National Key Laboratory of Air-based Information Perception and Fusion and the Aeronautic Science Foundation of China(No.20220001068001)。
文摘The paper presents a two-layer,disturbance-resistant,and fault-tolerant affine formation maneuver control scheme that accomplishes the surrounding of a dynamic target with multiple underactuated Quadrotor Unmanned Aerial Vehicles(QUAVs).This scheme mainly consists of predefinedtime estimators and fixed-time tracking controllers,with a hybrid Laplacian matrix describing the communication among these QUAVs.At the first layer,we devise predefined time estimators for leading and following QUAVs,enabling accurate estimation of desired information.In the second layer,we initially devise a fixed-time hybrid observer to estimate unknown disturbances and actuator faults.Fixedtime translational tracking controllers are then proposed,and the intermediary control input from these controllers is used to extract the desired attitude and angular velocities for the fixed-time rotational tracking controllers.We employ an exact tracking differentiator to handle variables that are challenging to differentiate directly.The paper includes a demonstration of the control system stability through mathematical proof,as well as the presentation of simulation results and comparative simulations.
基金supported by the National Natural Science Foundation of China(Nos.82073814,82122066,and 82104328)the"Dawn"Program of the Shanghai Education Commission(No.22SG34)+1 种基金the National Key Research and Development Program of the Ministry of China(No.2022YFC2704603)Shanghai Sailing Program(No.20YF1458900).
文摘Sini Decoction(SNT)is a traditional formula recognized for its efficacy in warming the spleen and stomach and dispersing cold.However,elucidating the mechanism of action of SNT remains challenging due to its complex multiple components.This study utilized a synergistic approach combining two-dimensional fluorescence difference in gel electrophoresis(2D-DIGE)-based drug affinity responsive target stability(DARTS)with label-free quantitative proteomics techniques to identify the direct and indirect protein targets of SNT in myocardial infarction.The analysis identified 590 proteins,with 30 proteins showing significant upregulation and 51 proteins showing downregulation when comparing the SNT group with the model group.Through the integration of 2D-DIGE DARTS with proteomics data and pharmacological assessments,the findings indicate that protein disulfide-isomerase A3(PDIA3)may serve as a potential protein target through which SNT provides protective effects on myocardial cells during myocardial infarction.
文摘纽结理论是拓扑学的一个重要分支,虚拟纽结理论是经典纽结理论的推广,对它的研究是通过一种图解理论来展开的。虚拟纽结多项式是一类以多项式表达的虚拟纽结不变量,例如Arrow多项式和Wriggle多项式。Affine index多项式是以虚拟纽结图的整数标记定义的单变量多项式。本文主要计算一类特殊虚拟纽结的Affine index多项式。按照Cheng着色的规则,对虚拟纽结图的每一段弧进行整数标记,计算每个经典交叉点的指标值,进而得到这类特殊虚拟纽结的Affine index多项式的表达式。Knot theory is an important branch of topology. Virtual knot theory is a generalization of classical knot theory, and its research is carried out through a graphic theory. The virtual knot polynomial refers to a class of virtual knot invariant expressed by polynomials, such as the Arrow polynomial and the Wriggle polynomial. The affine index polynomial is a univariate polynomial defined by the integer label of a virtual knot graph. In this paper, we mainly calculate affine index polynomials for a special class of virtual knots. According to the rules of Cheng coloring, we will integer label each arc of the virtual knot graph and calculate the index value of each classical crossings, and then get the expression of the affine index polynomial of this special virtual knot.
文摘Objective:Salvia miltiorrhiza is widely used in traditional Chinese medicine for treating cardiovascular and cerebrovascular diseases,with tanshinones being its major active components.This study aims to systematically elucidate the core transcriptional circuitry controlling tanshinone production,thereby establishing a mechanistic framework to optimize phytochemical yield and advance sustainable cultivation strategies for this pharmaceutically vital species.Methods:Transcriptome profiling revealed that the transcription factor SmWRKY69 is specifically expressed in the root periderm of S.miltiorrhiza.DNA affinity purification sequencing(DAPseq)was used to identify its potential target genes,and cis-element analysis predicted W-box motifs in the promoters of SmCPS1 and SmKSL1.Yeast one-hybrid(Y1H)assays were employed to validate its regulatory interactions with candidate gene promoters.Results:SmWRKY69 was found to directly bind to the promoters of SmCPS1 and SmKSL1,key genes in the tanshinone biosynthetic pathway,through W-box elements,indicating its role as a transcriptional regulator.Conclusion:SmWRKY69 regulates tanshinone biosynthesis by directly targeting SmCPS1 and SmKSL1,providing a valuable genetic target for metabolic engineering to enhance the therapeutic quality of S.miltiorrhiza.
基金supported by the Research Funding of Wuhan Polytechnic University(2024RZ083)Elisabeth M.Werner’s work was supported by the NSF grant DMS-2103482.Deping Ye’s work was supported by an NSERC grant,Canada.Ning Zhang’s work was supported by the NSF of China(11901217,11971005).
文摘In this article,we explain how the famous Archimedes’principle of flotation can be used to construct various floating bodies.We survey some of the most important results regarding the floating bodies,including their relations with affine surface area and projection body,their extensions in different settings such as space forms and log-concave functions,and mention some associated open problems.
基金supported by the National Natural Science Foundation of China(Nos.52303380,52025132,52273305,22205185,21621091,22021001,and 22121001)Fundamental Research Funds for the Central Universities(No.20720240041)+3 种基金the 111 Project(Nos.B17027 and B16029)the National Science Foundation of Fujian Province of China(No.2022J02059)the Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(No.RD2022070601)the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘Excessive Fe^(3+) ion concentrations in wastewater pose a long-standing threat to human health.Achieving low-cost,high-efficiency quantification of Fe^(3+) ion concentration in unknown solutions can guide environmental management decisions and optimize water treatment processes.In this study,by leveraging the rapid,real-time detection capabilities of nanopores and the specific chemical binding affinity of tannic acid to Fe^(3+),a linear relationship between the ion current and Fe^(3+) ion concentration was established.Utilizing this linear relationship,quantification of Fe^(3+) ion concentration in unknown solutions was achieved.Furthermore,ethylenediaminetetraacetic acid disodium salt was employed to displace Fe^(3+) from the nanopores,allowing them to be restored to their initial conditions and reused for Fe^(3+) ion quantification.The reusable bioinspired nanopores remain functional over 330 days of storage.This recycling capability and the long-term stability of the nanopores contribute to a significant reduction in costs.This study provides a strategy for the quantification of unknown Fe^(3+) concentration using nanopores,with potential applications in environmental assessment,health monitoring,and so forth.
基金Supported by National Natural Science Foundation of China(Grant No.12475002).
文摘In this paper,we shall study structures of even lattice vertex operator algebras by using the geometry of the varieties of their semi-conformal vectors.We first give the varieties of semi-conformal vectors of a family of vertex operator algebras V_(√kA_(1)) associated to rank-one positive definite even lattices √kA_(1) for arbitrary positive integers k to characterize these even lattice vertex operator algebras.In such a family of lattice vertex operator algebras V_(√kA_(1)),the vertex operator algebra V_(√2A_(1)) is different from others.Hence we describe the varieties of semi-conformal vectors of V_(√2A_(1)) and the fixed vertex operator subalgebra V^(+)√2A_(1).Moreover,as applications,we study the relations between vertex operator algebras V_(√kA_(1) )and L_(sl_(2))(k,0)for arbitrary positive integers k by the viewpoint of semi-conformal homomorphisms of vertex operator algebras.For case k=2,in the series of rational simple affine vertex operator algebras L_(sl_(2))(k,0)for positive integers k,we show that L_(sl_(2))(2,0)is a unique frame vertex operator algebra with rank 3.
基金Supported by the National Natural Science Foundation of China(No.61971162,61771186)the Natural Science Foundation of Heilongjiang Province(No.PL2024 F023)+1 种基金the Fundamental Scientific Research Funds of Heilongjiang Province(No.2022-KYYWF-1050)the Open Research Fund of National Mobile Communications Research Laboratory in Southeast University(No.2023D07).
文摘The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships between image pairs.Methods based on geometric transformation estimation usually perform affine transformation of the global image for viewpoint correction,which not only increases the time complexity but also generates a large number of redundant features.To solve this problem,this paper proposes an adaptive affine transformation model(AATM)to achieve robust image matching by dividing special regions with pixel information and employing feature extraction algorithms with different granularities.First,the input image is divided into significant and non-significant regions by an adaptive algorithm.Second,for the salient region,the feature point extraction is accelerated by optimizing the longitude angle sampling algorithm and constructing the affine invariant nonlinear scale space,introducing the Hessian integral image and box filter.Then,for the non-significant region of the weak texture scene through the uniform step sampling algorithm,a dense feature description can be obtained in the weak texture scenes,so that more robust features are extracted for both significant and non-significant regions.The results of extensive experiments on two datasets show that the AATM algorithm outperforms similar algorithms in terms of the number of correctly matched pairs,elapsed time,and root mean square error(RMSE),indicating that the AATM can obtain more robust matches in scenes with large angle tilting and scale transformations.
基金supported by the Shenzhen Key Laboratory of Intelligent Bioinformatics(No.ZDSYS20220422103800001)the Shenzhen Science and Technology Program(No.JCYJ20230807140709020)+2 种基金National Natural Science Foundation of China(Nos.62402489,U22A2041,and 62373172)the China Postdoctoral Science Foundation(No.2023M743688)Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515011960 and 2023A1515110570)。
文摘Artificial intelligence(AI)researchers and cheminformatics specialists strive to identify effective drug precursors while optimizing costs and accelerating development processes.Digital molecular representation plays a crucial role in achieving this objective by making molecules machine-readable,thereby enhancing the accuracy of molecular prediction tasks and facilitating evidence-based decision making.This study presents a comprehensive review of small molecular representations and AI-driven drug discovery downstream tasks utilizing these representations.The research methodology begins with the compilation of small molecule databases,followed by an analysis of fundamental molecular representations and the models that learn these representations from initial forms,capturing patterns and salient features across extensive chemical spaces.The study then examines various drug discovery downstream tasks,including drug-target interaction(DTI)prediction,drug-target affinity(DTA)prediction,drug property(DP)prediction,and drug generation,all based on learned representations.The analysis concludes by highlighting challenges and opportunities associated with machine learning(ML)methods for molecular representation and improving downstream task performance.Additionally,the representation of small molecules and AI-based downstream tasks demonstrates significant potential in identifying traditional Chinese medicine(TCM)medicinal substances and facilitating TCM target discovery.
基金This work was supported by the National Natural Science Foundation of China(51874332,51991363)the CNPC's Major Science and Technology Projects(ZD2019-184-003)+1 种基金the Fundamental Research Funds for Central Universities(20CX05008A)“14th Five-Year plan”forward-looking basic major science and technology project of CNPC(2021DJ4901).
文摘Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.
基金supported by the National Natural Science Foun-dation of China(Nos.22178275 and U22A20147)the Natural Science Foundation of Hubei Province of China(No.2022CFA001).
文摘In addition to the electron transfer,the appropriate H-adsorption affinity of active centers on the metal cocatalyst surface is quite important for high hydrogen-production activity of cocatalyst-modified photo-catalysts.The typical Cu and Ru metal cocatalysts clearly exhibit a weak Cu-H bond and a strong Ru-H bond,respectively,resulting in limited activity for photocatalytic H_(2)evolution.In this work,an ingenious strategy of self-optimized H-adsorption affinity in CuRu alloy cocatalyst is developed to simultaneously reinforce the Cu-H bond and weaken the Ru-H bond by the intrinsic electron transfer from Cu to Ru atom.The CuRu alloy nanoparticles(2-3 nm)were deposited on the TiO_(2)surface to prepare CuRu/TiO_(2)through a one-step photoreduction method.Photocatalytic tests exhibited that the highest H_(2)-production rate of CuRu/TiO_(2)photocatalyst reached up to 5.316 mmol h^(-1)g^(-1),which was 24.80,1.86,and 2.60 times higher than that of the TiO_(2),Cu/TiO_(2),and Ru/TiO_(2),respectively.Based on the characterization results and theoretical calculations,the CuRu alloy cocatalyst exhibits excellent self-optimized H-adsorption affinity via the spontaneous electron transfer from Cu to Ru atom,which can greatly accelerate the photocatalytic H_(2)-production rate of TiO_(2).This work provides a feasible idea for the self-optimized H-adsorption affinity of metal active sites in the photocatalytic H_(2)-generation field.
文摘In this paper,we compute sub-Riemannian limits of Gaussian curvature associated to two kinds of Schouten-Van Kampen affine connections and the adapted connection for a Euclidean C2-smooth surface in the Heisenberg group away from characteristic points and signed geodesic curvature associated to two kinds of Schouten-Van Kampen affine connections and the adapted connection for Euclidean C2-smooth curves on surfaces.We get Gauss-Bonnet theorems associated to two kinds of Schouten-Van Kampen affine connections in the Heisenberg group.
基金The National Natural Science Foundation of China under contract No.41721005the Fund of the Ministry of Natural Resources of the People’s Republic of China under contract Nos IRASCC 02-01-01 and 01-01-02C.
文摘Nitrification,a central process in the marine nitrogen cycle,produces regenerated nitrate in the euphotic zone and emits N_(2)O,a potent greenhouse gas as a by-product.The regulatory mechanisms of nitrification in the Southern Ocean,which is a critical region for CO_(2)sequestration and radiative benefits,remain poorly understood.Here,we investigated the in situ and dark nitrification rates in the upper 500 m and conducted substrate kinetics experiments across the Indian Sector in the Cosmonaut and Cooperation seas in the late austral summer.Our findings indicate that light inhibition of nitrification decreases exponentially with depth,exhibiting a light threshold of 0.53%photosynthetically active radiation.A positive relationship between dark nitrification and apparent oxygen utilization suggests a dependence on substrate availability from primary production.Importantly,an increased NH_(4)^(+) supply can act as a buffer against photo-inhibitory damage.Globally,substrate affinity(α)increases with depth and transitions from light to dark,decreases with increasing ambient NH_(4)^(+)and exhibits a latitudinal distribution,reflecting substrate utilization strategies.We also reveal that upwelling in Circumpolar Deep Water(CDW)stimulates nitrification through the introduction of potentially higher iron and deep diverse nitrifying microorganisms with higherα.We conclude that although light is the primary limiting factor for nitrification in summer,coupling between substrate availability and CDW upwelling can overcome this limitation,thereby alleviating photoinhibition by up to 45%±5.3%.
文摘[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under challenging conditions,such as strong light exposure and weed interference.The aims are to develop an effective crop line extraction method by combining YOLOv8-G,Affinity Propagation,and the Least Squares method to enhance detection accuracy and performance in complex field environments.[Methods]The proposed method employs machine vision techniques to address common field challenges.YOLOv8-G,an improved object detection algorithm that combines YOLOv8 and Ghost‐NetV2 for lightweight,high-speed performance,was used to detect the central points of crops.These points were then clustered using the Affinity Propagation algorithm,followed by the application of the Least Squares method to extract the crop lines.Comparative tests were conducted to evaluate multiple backbone networks within the YOLOv8 framework,and ablation studies were performed to validate the enhancements made in YOLOv8-G.[Results and Discussions]The performance of the proposed method was compared with classical object detection and clustering algorithms.The YOLOv8-G algorithm achieved average precision(AP)values of 98.22%,98.15%,and 97.32%for corn detection at 7,14,and 21 days after emergence,respectively.Additionally,the crop line extraction accuracy across all stages was 96.52%.These results demonstrate the model's ability to maintain high detection accuracy despite challenging conditions in the field.[Conclusions]The proposed crop line extraction method effectively addresses field challenges such as lighting and weed interference,enabling rapid and accurate crop identification.This approach supports the automatic navigation of agricultural machinery,offering significant improvements in the precision and efficiency of field operations.
