BACKGROUND In pediatric age group patients(<18 years old)treated operatively for distal radius/both bone fractures extending imaging beyond the initial postoperative period-particularly in uncomplicated cases-appea...BACKGROUND In pediatric age group patients(<18 years old)treated operatively for distal radius/both bone fractures extending imaging beyond the initial postoperative period-particularly in uncomplicated cases-appears to provide limited additional benefit.AIM To determine the necessary number of follow-up X-rays to use resources efficiently.METHODS Participants included in this study are pediatric age group patients who were treated operatively for distal radius/both bone fractures and were identified from a prospected collected data from the operating room database between the years 2009 and 2017.The data in the study included patients who had distal radius fractures and underwent fixation surgery(n=88).RESULTS When assessing the difference in the odds of conducting 1 or less X-ray compared to 2 or more X-rays in regard to the type of fixation,the only significant difference is the closed reduction fixation method.Patients who underwent closed reduction method procedure have significantly lower odds of having 2 more X-rays compared to those who didn’t have closed reduction method.Open reduction,internal fixation,and other fixation methods(close reduction and internal fixation,debridement,or epiphysiodesis)have higher odds of having two or more X-rays compared to patients who did not receive these methods;however,these odds are not statistically significant.CONCLUSION The findings of this study reveal notable absence of a statistically significant association between the frequency of postoperative X-rays and the outcome of children with distal radius fractures.展开更多
This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh ...This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh principle and the perturbation of the spectral radius under moving the edge operation,and the extremal hypergraphs are characterized for both supertree and unicyclic hypergraphs.The spectral radius of the graph is generalized.展开更多
For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant verti...For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant vertices,whereβe{1,2,3,4,n-3,n-2,n-1}.展开更多
For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G)...For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G),α∈[0,1].The Aa-spectral radius is the largest eigenvalue of A_(α)(G).Let G_(n,β) be the set graphs with order n and dissociation numberβ.In this paper,we identify the b with maximal A_(α)-spectral radius among all graphs in G_(n,β).展开更多
Background and Objectives: The distal radius fracture (DRF) is a major public health problem in northern countries. Its frequency is constantly increasing. The locked anterior plate with its well-established biomechan...Background and Objectives: The distal radius fracture (DRF) is a major public health problem in northern countries. Its frequency is constantly increasing. The locked anterior plate with its well-established biomechanical properties, offers a reliable alternative. The aim of this study was to evaluate the radiological, the functional results and to determine the factors of poor postoperative prognosis of DRF treated with Newclip radial plates®. Methodology: This prospective cohort study evaluates the radiological and functional outcames of displaced radius fractures (DRFs) in patients ≥50 years old treated with Newclip® (locked anterior plates) at the Basse-Terre Hospital in Guadeloupe from 2022 to 2024. The patients were categorized into those with epiphyseal involvement (E1 - E4) and without epiphyseal involvement (E0) based on Laulan’s MEU classification. Radiological parameters (distal radio-ulnar index (DRUI), radial inclination frant view (IRF), radial inclination sagittal view (IRS) were assessed pre and post-operatively. Functional recovery was evaluated at 12 months using the QuickDash questionnaire. Results: Falls were the most common cause of fracture. Post-operatively, SRI was the least restored parameter. Poor prognostic factor for SRI improvement included posterior commimution and unstable fractures. Factors associated with higher QuickDash scores included unstable factures, unrestored DRUI, low plate position, metaphyseal features, and ulnar features. Conclusion: The anterior locking plate osteosynthesis is reliable treatment option with excellent functional outcomes.展开更多
This paper presents a deep learning architecture combined with exploratory data analysis to estimate maximum wall deflection in deep excavations.Six major geotechnical parameters were studied.Statistical methods,such ...This paper presents a deep learning architecture combined with exploratory data analysis to estimate maximum wall deflection in deep excavations.Six major geotechnical parameters were studied.Statistical methods,such as pair plots and Pearson correlation,highlighted excavation depth(correlation coefficient=0.82)as the most significant factor.For method prediction,five deep learning models(CNN,LSTM,BiLSTM,CNN-LSTM,and CNN-BiLSTM)were built.The CNN-BiLSTM model excelled in training performance(R^(2)=0.98,RMSE=0.02),while BiLSTM reached superior testing results(R^(2)=0.85,RMSE=0.06),suggesting greater generalization ability.Based on the feature importance analysis from model weights,excavation depth,stiffness ratio,and bracing spacing were ranked as the highest contributors.This point verified a lack of prediction bias on residual plots and high model agreement with measured values on Taylor diagrams(correlation coefficient 0.92).The effectiveness of integrated techniques was reliably assured for predicting wall deformation.This approach facilitates more accurate and efficient geotechnical design and provides engineers with improved tools for risk evaluation and decision-making in deep excavation projects.展开更多
In weak field limits,we compute the deflection angle of a gravitational decoupling extended black hole(BH)solution.We obtained the Gaussian optical curvature by examining the null geodesic equations with the help of G...In weak field limits,we compute the deflection angle of a gravitational decoupling extended black hole(BH)solution.We obtained the Gaussian optical curvature by examining the null geodesic equations with the help of Gauss-Bonnet theorem(GBT).We also looked into the deflection angle of light by a black hole in weak field limits with the use of the Gibbons-Werner method.We verify the graphical behavior of the black hole after determining the deflection angle of light.Additionally,in the presence of the plasma medium,we also determine the deflection angle of the light and examine its graphical behavior.Furthermore,we compute the Einstein ring via gravitational decoupling extended black hole solution.We also compute the quasi-periodic oscillations and discuss their graphical behavior.展开更多
Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of...Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of AL/CR in diagnosing myopia in children.Methods:A cross-sectional study was conducted.A total of 200 children(400 eyes)aged 6-12 years were recruited from the ophthalmology outpatient clinic of Fuling District People’s Hospital from December 2022 to December 2023.AL,CR,and AL/CR were measured,and comprehensive optometry was performed under cycloplegia,with the results recorded in spherical equivalent(SE)form.Results:A total of 200 subjects(400 eyes)were included in this study,of which 330 eyes(82.50%)were myopic.No significant differences in CR were observed among different refractive groups,while significant differences were noted in SE,AL,and AL/CR.The AL and AL/CR ratios were higher in myopic eyes compared to emmetropic and hyperopic eyes.Using cycloplegia as the gold standard,SE in the myopia group was correlated with AL,AL/CR,and CR,with stronger correlations observed with AL and AL/CR.An AL/CR value>3 demonstrated a sensitivity of 0.918,specificity of 0.786,misdiagnosis rate of 0.214,missed diagnosis rate of 0.082,and accuracy of 89.5%in diagnosing myopia.Conclusion:AL and AL/CR values are highly correlated with SE,with the strongest correlation observed in the myopia group.The AL/CR value exhibits high diagnostic value in determining myopia in children.展开更多
Cold-flow experiments on planar Expansion Deflection(ED)nozzle flows are conducted under a simulated startup-shutdown process of rocket motors.The purpose is to investigate the flow and performance characteristics in ...Cold-flow experiments on planar Expansion Deflection(ED)nozzle flows are conducted under a simulated startup-shutdown process of rocket motors.The purpose is to investigate the flow and performance characteristics in ED nozzles,capture the behavior of shock flapping,and explore asymmetric flow dynamics utilizing a symmetric nozzle.A total pressure condition,characterized by rapid rise followed by a slow fall,is employed to simulate the continuous startup and shutdown processes.The schlieren imaging technique and high-frequency pressure transducers are employed to obtain the flow information.The experimental results indicate that the flow characteristics differ between the startup and shutdown processes with a hysteresis observed in the nozzle wake mode transition.During the startup process,the shock waves are pushed outward of the nozzle,while during the shutdown process,the flow propagates inward dominated by Mach stems.Counterintuitive results are demonstrated,namely,the mode transition is not the cause of the sudden thrust decrease,and the moment of maximum thrust does not coincide with the moment of maximum total pressure.During the operation of the nozzle,two stages of shock wave flapping occur,accompanied by significant wall pressure oscillations.These oscillation frequencies are demonstrated to be related to the inherent acoustic frequencies of the test chamber.An improved pressure ratio method is proposed to predict the position of the shock oscillation separation point.The prediction results revealed the shock behavior during the flapping process.展开更多
The challenge of solving nonlinear problems in multi-connected domains with high accuracy has garnered significant interest.In this paper,we propose a unified wavelet solution method for accurately solving nonlinear b...The challenge of solving nonlinear problems in multi-connected domains with high accuracy has garnered significant interest.In this paper,we propose a unified wavelet solution method for accurately solving nonlinear boundary value problems on a two-dimensional(2D)arbitrary multi-connected domain.We apply this method to solve large deflection bending problems of complex plates with holes.Our solution method simplifies the treatment of the 2D multi-connected domain by utilizing a natural discretization approach that divides it into a series of one-dimensional(1D)intervals.This approach establishes a fundamental relationship between the highest-order derivative in the governing equation of the problem and the remaining lower-order derivatives.By combining a wavelet high accuracy integral approximation format on 1D intervals,where the convergence order remains constant regardless of the number of integration folds,with the collocation method,we obtain a system of algebraic equations that only includes discrete point values of the highest order derivative.In this process,the boundary conditions are automatically replaced using integration constants,eliminating the need for additional processing.Error estimation and numerical results demonstrate that the accuracy of this method is unaffected by the degree of nonlinearity of the equations.When solving the bending problem of multi-perforated complex-shaped plates under consideration,it is evident that directly using higher-order derivatives as unknown functions significantly improves the accuracy of stress calculation,even when the stress exhibits large gradient variations.Moreover,compared to the finite element method,the wavelet method requires significantly fewer nodes to achieve the same level of accuracy.Ultimately,the method achieves a sixth-order accuracy and resembles the treatment of one-dimensional problems during the solution process,effectively avoiding the need for the complex 2D meshing process typically required by conventional methods when solving problems with multi-connected domains.展开更多
A graph is called k-extendable if each k-matching can be extended to a perfect matching.In this paper,we provide a sufficient condition in terms of the Aa-spectral radius for the k-extendability of a connected graph a...A graph is called k-extendable if each k-matching can be extended to a perfect matching.In this paper,we provide a sufficient condition in terms of the Aa-spectral radius for the k-extendability of a connected graph and characterize the corresponding extremal graphs.In addition,such an A_(α)-spectral condition of a connected balanced bipartite graph is also considered,and the corresponding extremal graphs are determined.展开更多
Routine postoperative radiographs after surgical fixation of pediatric distal-radius fractures have long been part of standard care.Yet growing evidence shows that these images rarely change management in stable cases...Routine postoperative radiographs after surgical fixation of pediatric distal-radius fractures have long been part of standard care.Yet growing evidence shows that these images rarely change management in stable cases,adding unnecessary cost,radiation exposure,and clinical burden.A recent study highlights this issue and questions whether routine imaging truly benefits patient outcomes.As orthopedic care shifts toward more patient-centered and value-driven models,there is increasing support for the judicious use of radiographs,reserving imaging for cases where clinical examination or patient symptoms suggest a potential problem.This shift would reflect a broader movement within orthopedic practice:Aligning tradition with necessity,and optimizing care based on evidence rather than habit.展开更多
Let G be a graph andαÎ[0,1),Nikiforov merged the adjacency matrix and the signless Laplacian matrix to A_(α)(G)=αD(G)+(1-α)A(G),where D(G)A(G)are the degree diagonal matrix and the adjacency matrix of G,respe...Let G be a graph andαÎ[0,1),Nikiforov merged the adjacency matrix and the signless Laplacian matrix to A_(α)(G)=αD(G)+(1-α)A(G),where D(G)A(G)are the degree diagonal matrix and the adjacency matrix of G,respectively.The spectral radius of A_(α)(G)is called byα-spectral radius of the graph G.In this paper,we study the perturbation of the complete multipartite graphsα-spectral radius when move a vertex from a part to other part of the complete multipartite graphs.Moreover,we give some conditions when theα-spectral Turán of graphs implies the Turán theorem of graphs.展开更多
BACKGROUND The volar approach with plate fixation is the gold standard for treating distal radius fractures,often requiring incision of the pronator quadratus(PQ)muscle.Preserving the PQ during surgery may facilitate ...BACKGROUND The volar approach with plate fixation is the gold standard for treating distal radius fractures,often requiring incision of the pronator quadratus(PQ)muscle.Preserving the PQ during surgery may facilitate early postoperative recovery.However,conventional minimally invasive plate osteosynthesis(MIPO)techniques frequently necessitate multiple(3-4)intraoperative fluoroscopic adjustments to achieve optimal plate positioning,which can inadvertently damage the PQ muscle.Based on our clinical observations,we developed a novel 3-point positioning technique to minimize PQ injury while ensuring accurate plate placement.Preliminary results demonstrate promising early clinical outcomes.AIM To retrospectively analyze distal radius fractures treated using the 3-point positioning-assisted MIPO technique with preservation of the PQ.METHODS The 3-point positioning technique was applied:The Kirschner wire was inserted after fluoroscopy and was correctly adjusted the position of the plate above the PQ.With the aid of Kirschner wires positioning the PQ stripping was performed only once,and the plate then placed in a correct and satisfactory position.Operation time,incision length,wrist pain score,upper extremity function disabilities of the arm,shoulder and hand(DASH)score,wrist Gartland-Werley score,wrist grip strength,and range of motion were among the quantitative variables recorded.Qualitative variables including AO fracture classification,intraoperative and postoperative complications were evaluated.RESULTS At a mean follow-up of 6.9±0.8 months,the mean scar length was 25.4±1.5 mm,the pain score was 0.7±0.6,the DASH score for the upper limb was 4.7±1.3,and the Gartland-Werley score for wrist function was 4.1±1.1 at the last follow-up.Mean flexion was 97.3%,extension was 97.0%,pronation was 98.9%,supination was 98.9%,and grip strength was 86.6%compared to contralateral values.No unfavorable intraoperative or postoperative complications occurred.CONCLUSION The 3-point positioning technique may reduce the damage to the PQ muscle and is a safe and effective method for MIPO for distal radius fractures.展开更多
To improve the drill pipe fracture failure phenomenon in deflecting drills with ultra-short radius flexible drill pipes,this study establishes a mechanical model of a deflecting drill with an ultra-short radius flexib...To improve the drill pipe fracture failure phenomenon in deflecting drills with ultra-short radius flexible drill pipes,this study establishes a mechanical model of a deflecting drill with an ultra-short radius flexible drill pipe,numerically simulates the mechanical characteristics of the flexible drill pipe under the conventional drilling process using the finite element analysis method,performs mechanical performance tests on the flexible drill pipe,and optimizes and improves its structure.The results show that,with the gradual increase in the bending angle of the flexible drill pipe unit section,the upper drilling pressure of the flexible drill pipe unit section decreases rapidly and its friction increases approximately linearly.The tensile strength of the optimized ultra-short radius flexible drill pipe is increased by 24.7%,and the minimum threshold of its torsional strength is doubled.This effectively improves the overall strength of the ultra-short radius flexible drill pipe and provides a theoretical basis for downhole drilling stability studies of flexible drill pipes.展开更多
文摘BACKGROUND In pediatric age group patients(<18 years old)treated operatively for distal radius/both bone fractures extending imaging beyond the initial postoperative period-particularly in uncomplicated cases-appears to provide limited additional benefit.AIM To determine the necessary number of follow-up X-rays to use resources efficiently.METHODS Participants included in this study are pediatric age group patients who were treated operatively for distal radius/both bone fractures and were identified from a prospected collected data from the operating room database between the years 2009 and 2017.The data in the study included patients who had distal radius fractures and underwent fixation surgery(n=88).RESULTS When assessing the difference in the odds of conducting 1 or less X-ray compared to 2 or more X-rays in regard to the type of fixation,the only significant difference is the closed reduction fixation method.Patients who underwent closed reduction method procedure have significantly lower odds of having 2 more X-rays compared to those who didn’t have closed reduction method.Open reduction,internal fixation,and other fixation methods(close reduction and internal fixation,debridement,or epiphysiodesis)have higher odds of having two or more X-rays compared to patients who did not receive these methods;however,these odds are not statistically significant.CONCLUSION The findings of this study reveal notable absence of a statistically significant association between the frequency of postoperative X-rays and the outcome of children with distal radius fractures.
基金Supported by Natural Science Foundation of HuBei Province(2022CFB299).
文摘This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh principle and the perturbation of the spectral radius under moving the edge operation,and the extremal hypergraphs are characterized for both supertree and unicyclic hypergraphs.The spectral radius of the graph is generalized.
文摘For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant vertices,whereβe{1,2,3,4,n-3,n-2,n-1}.
基金Supported by NSFC (Nos.12171089,12271235)NSF of Jiangsu (No.BK20190919)NSF of Fujian (No.2021J02048)。
文摘For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G),α∈[0,1].The Aa-spectral radius is the largest eigenvalue of A_(α)(G).Let G_(n,β) be the set graphs with order n and dissociation numberβ.In this paper,we identify the b with maximal A_(α)-spectral radius among all graphs in G_(n,β).
文摘Background and Objectives: The distal radius fracture (DRF) is a major public health problem in northern countries. Its frequency is constantly increasing. The locked anterior plate with its well-established biomechanical properties, offers a reliable alternative. The aim of this study was to evaluate the radiological, the functional results and to determine the factors of poor postoperative prognosis of DRF treated with Newclip radial plates®. Methodology: This prospective cohort study evaluates the radiological and functional outcames of displaced radius fractures (DRFs) in patients ≥50 years old treated with Newclip® (locked anterior plates) at the Basse-Terre Hospital in Guadeloupe from 2022 to 2024. The patients were categorized into those with epiphyseal involvement (E1 - E4) and without epiphyseal involvement (E0) based on Laulan’s MEU classification. Radiological parameters (distal radio-ulnar index (DRUI), radial inclination frant view (IRF), radial inclination sagittal view (IRS) were assessed pre and post-operatively. Functional recovery was evaluated at 12 months using the QuickDash questionnaire. Results: Falls were the most common cause of fracture. Post-operatively, SRI was the least restored parameter. Poor prognostic factor for SRI improvement included posterior commimution and unstable fractures. Factors associated with higher QuickDash scores included unstable factures, unrestored DRUI, low plate position, metaphyseal features, and ulnar features. Conclusion: The anterior locking plate osteosynthesis is reliable treatment option with excellent functional outcomes.
文摘This paper presents a deep learning architecture combined with exploratory data analysis to estimate maximum wall deflection in deep excavations.Six major geotechnical parameters were studied.Statistical methods,such as pair plots and Pearson correlation,highlighted excavation depth(correlation coefficient=0.82)as the most significant factor.For method prediction,five deep learning models(CNN,LSTM,BiLSTM,CNN-LSTM,and CNN-BiLSTM)were built.The CNN-BiLSTM model excelled in training performance(R^(2)=0.98,RMSE=0.02),while BiLSTM reached superior testing results(R^(2)=0.85,RMSE=0.06),suggesting greater generalization ability.Based on the feature importance analysis from model weights,excavation depth,stiffness ratio,and bracing spacing were ranked as the highest contributors.This point verified a lack of prediction bias on residual plots and high model agreement with measured values on Taylor diagrams(correlation coefficient 0.92).The effectiveness of integrated techniques was reliably assured for predicting wall deformation.This approach facilitates more accurate and efficient geotechnical design and provides engineers with improved tools for risk evaluation and decision-making in deep excavation projects.
基金funded by the National Natural Science Foundation of China under Grant No.11975145。
文摘In weak field limits,we compute the deflection angle of a gravitational decoupling extended black hole(BH)solution.We obtained the Gaussian optical curvature by examining the null geodesic equations with the help of Gauss-Bonnet theorem(GBT).We also looked into the deflection angle of light by a black hole in weak field limits with the use of the Gibbons-Werner method.We verify the graphical behavior of the black hole after determining the deflection angle of light.Additionally,in the presence of the plasma medium,we also determine the deflection angle of the light and examine its graphical behavior.Furthermore,we compute the Einstein ring via gravitational decoupling extended black hole solution.We also compute the quasi-periodic oscillations and discuss their graphical behavior.
基金Chongqing Fuling District Science and Health Joint Medical Research Project(2022KWLH069)。
文摘Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of AL/CR in diagnosing myopia in children.Methods:A cross-sectional study was conducted.A total of 200 children(400 eyes)aged 6-12 years were recruited from the ophthalmology outpatient clinic of Fuling District People’s Hospital from December 2022 to December 2023.AL,CR,and AL/CR were measured,and comprehensive optometry was performed under cycloplegia,with the results recorded in spherical equivalent(SE)form.Results:A total of 200 subjects(400 eyes)were included in this study,of which 330 eyes(82.50%)were myopic.No significant differences in CR were observed among different refractive groups,while significant differences were noted in SE,AL,and AL/CR.The AL and AL/CR ratios were higher in myopic eyes compared to emmetropic and hyperopic eyes.Using cycloplegia as the gold standard,SE in the myopia group was correlated with AL,AL/CR,and CR,with stronger correlations observed with AL and AL/CR.An AL/CR value>3 demonstrated a sensitivity of 0.918,specificity of 0.786,misdiagnosis rate of 0.214,missed diagnosis rate of 0.082,and accuracy of 89.5%in diagnosing myopia.Conclusion:AL and AL/CR values are highly correlated with SE,with the strongest correlation observed in the myopia group.The AL/CR value exhibits high diagnostic value in determining myopia in children.
基金supported by the National Natural Science Foundation of China(No.12002102)。
文摘Cold-flow experiments on planar Expansion Deflection(ED)nozzle flows are conducted under a simulated startup-shutdown process of rocket motors.The purpose is to investigate the flow and performance characteristics in ED nozzles,capture the behavior of shock flapping,and explore asymmetric flow dynamics utilizing a symmetric nozzle.A total pressure condition,characterized by rapid rise followed by a slow fall,is employed to simulate the continuous startup and shutdown processes.The schlieren imaging technique and high-frequency pressure transducers are employed to obtain the flow information.The experimental results indicate that the flow characteristics differ between the startup and shutdown processes with a hysteresis observed in the nozzle wake mode transition.During the startup process,the shock waves are pushed outward of the nozzle,while during the shutdown process,the flow propagates inward dominated by Mach stems.Counterintuitive results are demonstrated,namely,the mode transition is not the cause of the sudden thrust decrease,and the moment of maximum thrust does not coincide with the moment of maximum total pressure.During the operation of the nozzle,two stages of shock wave flapping occur,accompanied by significant wall pressure oscillations.These oscillation frequencies are demonstrated to be related to the inherent acoustic frequencies of the test chamber.An improved pressure ratio method is proposed to predict the position of the shock oscillation separation point.The prediction results revealed the shock behavior during the flapping process.
基金supported by the National Natural Science Foundation of China(Grant No.11925204).
文摘The challenge of solving nonlinear problems in multi-connected domains with high accuracy has garnered significant interest.In this paper,we propose a unified wavelet solution method for accurately solving nonlinear boundary value problems on a two-dimensional(2D)arbitrary multi-connected domain.We apply this method to solve large deflection bending problems of complex plates with holes.Our solution method simplifies the treatment of the 2D multi-connected domain by utilizing a natural discretization approach that divides it into a series of one-dimensional(1D)intervals.This approach establishes a fundamental relationship between the highest-order derivative in the governing equation of the problem and the remaining lower-order derivatives.By combining a wavelet high accuracy integral approximation format on 1D intervals,where the convergence order remains constant regardless of the number of integration folds,with the collocation method,we obtain a system of algebraic equations that only includes discrete point values of the highest order derivative.In this process,the boundary conditions are automatically replaced using integration constants,eliminating the need for additional processing.Error estimation and numerical results demonstrate that the accuracy of this method is unaffected by the degree of nonlinearity of the equations.When solving the bending problem of multi-perforated complex-shaped plates under consideration,it is evident that directly using higher-order derivatives as unknown functions significantly improves the accuracy of stress calculation,even when the stress exhibits large gradient variations.Moreover,compared to the finite element method,the wavelet method requires significantly fewer nodes to achieve the same level of accuracy.Ultimately,the method achieves a sixth-order accuracy and resembles the treatment of one-dimensional problems during the solution process,effectively avoiding the need for the complex 2D meshing process typically required by conventional methods when solving problems with multi-connected domains.
基金Supported by the National Natural Science Foundation of China(11961041,12261055)the Key Project of Natural Science Foundation of Gansu Province(24JRRA222)。
文摘A graph is called k-extendable if each k-matching can be extended to a perfect matching.In this paper,we provide a sufficient condition in terms of the Aa-spectral radius for the k-extendability of a connected graph and characterize the corresponding extremal graphs.In addition,such an A_(α)-spectral condition of a connected balanced bipartite graph is also considered,and the corresponding extremal graphs are determined.
文摘Routine postoperative radiographs after surgical fixation of pediatric distal-radius fractures have long been part of standard care.Yet growing evidence shows that these images rarely change management in stable cases,adding unnecessary cost,radiation exposure,and clinical burden.A recent study highlights this issue and questions whether routine imaging truly benefits patient outcomes.As orthopedic care shifts toward more patient-centered and value-driven models,there is increasing support for the judicious use of radiographs,reserving imaging for cases where clinical examination or patient symptoms suggest a potential problem.This shift would reflect a broader movement within orthopedic practice:Aligning tradition with necessity,and optimizing care based on evidence rather than habit.
基金The National Science Foundation of China(12371349,12471331)。
文摘Let G be a graph andαÎ[0,1),Nikiforov merged the adjacency matrix and the signless Laplacian matrix to A_(α)(G)=αD(G)+(1-α)A(G),where D(G)A(G)are the degree diagonal matrix and the adjacency matrix of G,respectively.The spectral radius of A_(α)(G)is called byα-spectral radius of the graph G.In this paper,we study the perturbation of the complete multipartite graphsα-spectral radius when move a vertex from a part to other part of the complete multipartite graphs.Moreover,we give some conditions when theα-spectral Turán of graphs implies the Turán theorem of graphs.
基金Supported by Fujian Provincial Clinical Medical Research Center for First Aid and Rehabilitation in Orthopaedic Trauma,No.2020Y2014Fuzhou Health Technology Innovation Platform Construction Project,No.2019-S-wp2.
文摘BACKGROUND The volar approach with plate fixation is the gold standard for treating distal radius fractures,often requiring incision of the pronator quadratus(PQ)muscle.Preserving the PQ during surgery may facilitate early postoperative recovery.However,conventional minimally invasive plate osteosynthesis(MIPO)techniques frequently necessitate multiple(3-4)intraoperative fluoroscopic adjustments to achieve optimal plate positioning,which can inadvertently damage the PQ muscle.Based on our clinical observations,we developed a novel 3-point positioning technique to minimize PQ injury while ensuring accurate plate placement.Preliminary results demonstrate promising early clinical outcomes.AIM To retrospectively analyze distal radius fractures treated using the 3-point positioning-assisted MIPO technique with preservation of the PQ.METHODS The 3-point positioning technique was applied:The Kirschner wire was inserted after fluoroscopy and was correctly adjusted the position of the plate above the PQ.With the aid of Kirschner wires positioning the PQ stripping was performed only once,and the plate then placed in a correct and satisfactory position.Operation time,incision length,wrist pain score,upper extremity function disabilities of the arm,shoulder and hand(DASH)score,wrist Gartland-Werley score,wrist grip strength,and range of motion were among the quantitative variables recorded.Qualitative variables including AO fracture classification,intraoperative and postoperative complications were evaluated.RESULTS At a mean follow-up of 6.9±0.8 months,the mean scar length was 25.4±1.5 mm,the pain score was 0.7±0.6,the DASH score for the upper limb was 4.7±1.3,and the Gartland-Werley score for wrist function was 4.1±1.1 at the last follow-up.Mean flexion was 97.3%,extension was 97.0%,pronation was 98.9%,supination was 98.9%,and grip strength was 86.6%compared to contralateral values.No unfavorable intraoperative or postoperative complications occurred.CONCLUSION The 3-point positioning technique may reduce the damage to the PQ muscle and is a safe and effective method for MIPO for distal radius fractures.
基金supported by Open Fund of Technology Innovation Center for Directional Drilling Engineering,Ministry of Natural Resources./Innovation Base for Directional Drilling Engineering,Geological Society of China(-No.KF202302)the Geological Survey projects of China Geological Survey(No.DD20221681)+1 种基金Open Found Projects of Sinopec Key Laboratory of Geothermal Resources Exploitation and Utilizatio(No.36650000-23-ZC0607-0054)Open Research Fund Program of Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Ministry of Education),Central South University(2023YSJS06).
文摘To improve the drill pipe fracture failure phenomenon in deflecting drills with ultra-short radius flexible drill pipes,this study establishes a mechanical model of a deflecting drill with an ultra-short radius flexible drill pipe,numerically simulates the mechanical characteristics of the flexible drill pipe under the conventional drilling process using the finite element analysis method,performs mechanical performance tests on the flexible drill pipe,and optimizes and improves its structure.The results show that,with the gradual increase in the bending angle of the flexible drill pipe unit section,the upper drilling pressure of the flexible drill pipe unit section decreases rapidly and its friction increases approximately linearly.The tensile strength of the optimized ultra-short radius flexible drill pipe is increased by 24.7%,and the minimum threshold of its torsional strength is doubled.This effectively improves the overall strength of the ultra-short radius flexible drill pipe and provides a theoretical basis for downhole drilling stability studies of flexible drill pipes.
