The sources and accumulation of heavy metals in soil are of great significance for soil utilization and pollution control.Lead(Pb),a common heavy metal element,tends to accumulate in the soils with time.Excess Pb in s...The sources and accumulation of heavy metals in soil are of great significance for soil utilization and pollution control.Lead(Pb),a common heavy metal element,tends to accumulate in the soils with time.Excess Pb in soils accumulates in plants and becomes toxic to humans and livestock when it enters the food chain.The historical data of Pb contents in soils in northwest China were stud-ied to establish the historical change curve in this paper.The results indicate geochemical background and wind and dust deposition have the minor contribution to the accumulation of Pb in soils,but human activities have caused a rapid accumulation of Pb in soils.From 1990 to 2020,the accumulation of about 0.1 mg/kg of Pb in the soils is due to natural wind-dust deposits,but the content of Pb in the soils has nearly tripled from about 22 mg/kg to about 52 mg/kg with the process of anthropogenic urbanization and industrialization.We found that the influence of human activities on lead content was closely related to the total primary energy production(10,000 tons of SCE),and the evolution of soil Pb contents in the study area was consis-tent with the Allometric1 model.展开更多
Objectives:PI3K plays a pivotal role in the inflammatory response by modulating the production and release of inflammatory factors.Pik3cb is one of the subunits of PI3K,and its specific role in myocardium inflammation...Objectives:PI3K plays a pivotal role in the inflammatory response by modulating the production and release of inflammatory factors.Pik3cb is one of the subunits of PI3K,and its specific role in myocardium inflammation remains unelucidated.This study aimed to investigate the role of Pik3cb in the inflammatory response and to elucidate the underlying mechanism.Methods:An inflammation model was established using H9c2 cells treated with LPS and ATP,and Pik3cb expression was evaluated in this model system.Subsequently,an overexpression model was constructed by transfecting cells with a Pik3cb overexpression plasmid,after which the effects of Pik3cb overexpression on the PI3K/AKT and NF-κB/NLRP3 inflammatory signaling pathways were assessed.Results:These analyses revealed that the expression and distribution of Pik3cb were significantly reduced in the LPS/ATP-induced cellular inflammation model group,whereas plasmid-mediated overexpression of Pik3cb significantly inhibited the activation of the PI3K/AKT signaling pathway in response to LPS/ATP stimulation.Additionally,the LPS/ATP-induced activation of the NF-κB/NLRP3 axis was significantly inhibited following Pik3cb overexpression.Conclusion:This study demonstrates that Pik3cb acts as a negative regulator of LPS/ATP-induced inflammation in cardiomyocytes,exerting anti-inflammatory effects by inhibiting the PI3K/AKT/NF-κB/NLRP3 signaling axis.These findings provide a potential therapeutic target for the treatment of myocardial inflammation.展开更多
A multi-body dynamic rigid-flexible coupling model of landing gear is established to study the gear walk instability caused by the friction characteristics of the brake disc.After validating the model with the experim...A multi-body dynamic rigid-flexible coupling model of landing gear is established to study the gear walk instability caused by the friction characteristics of the brake disc.After validating the model with the experimental results,the influence of the landing gear structure and braking system parameters on gear walk is further investigated.Among the above factors,the slope of the graph for the friction coefficient of the brake disc and the relative velocity of brake stators and rotors is the most influential factor on gear walk instability.Phase trajectory analysis verifies that gear walk occurs when the coupling of multiple factors causes the system to exhibit an equivalent negative damping trend.To consider a more realistic braking case,a back propagation neural network method is employed to describe the nonlinear behavior of the friction coefficient of the brake disc.With the realistic nonlinear model of the friction coefficient,the maximum error in predicting the braking torque is less than 10%and the effect of the brake disc temperature on gear walk is performed.The results reveal that a more negative friction slope may contribute to a more severe unstable gear walk,and reducing the braking pressure is an effective approach to avoid gear walk,which provides help for future braking system design.展开更多
In this paper,we formulate the precoding problem of integrated sensing and communication(ISAC)waveform as a non-convex quadratically constrained quadratic programming(QCQP),in which the weighted sum of communication m...In this paper,we formulate the precoding problem of integrated sensing and communication(ISAC)waveform as a non-convex quadratically constrained quadratic programming(QCQP),in which the weighted sum of communication multi-user interference(MUI)and the gap between dual-use waveform and ideal radar waveform is minimized with peak-toaverage power ratio(PAPR)constraints.We propose an efficient algorithm based on alternating direction method of multipliers(ADMM),which is able to decouple multiple variables and provide a closed-form solution for each subproblem.In addition,to improve the sensing performance in both spatial and temporal domains,we propose a new criteria to design the ideal radar waveform,in which the beam pattern is made similar to the ideal one and the integrated sidelobe level of the ambiguity function in each target direction is minimized in the region of interest.The limited memory Broyden-Fletcher-Goldfarb-Shanno(LBFGS)algorithm is applied to the design of the ideal radar waveform which works as a reference in the design of the dual-function waveform.Numerical results indicate that the designed dual-function waveform is capable of offering good communication quality of service(QoS)and sensing performance.展开更多
基金supported by the National Natural Science Foundation of China(Grant number:41440027)Geological Prospecting Fund of Qinghai Province(Grant number:2017042185sh029)Special project of Key Laboratory of Environmental Geology of Qinghai Province(Grant number:2023-KJ-13).Our special appreciate go to the editors and anonymous reviewers for their critical reviews and helpful comments.
文摘The sources and accumulation of heavy metals in soil are of great significance for soil utilization and pollution control.Lead(Pb),a common heavy metal element,tends to accumulate in the soils with time.Excess Pb in soils accumulates in plants and becomes toxic to humans and livestock when it enters the food chain.The historical data of Pb contents in soils in northwest China were stud-ied to establish the historical change curve in this paper.The results indicate geochemical background and wind and dust deposition have the minor contribution to the accumulation of Pb in soils,but human activities have caused a rapid accumulation of Pb in soils.From 1990 to 2020,the accumulation of about 0.1 mg/kg of Pb in the soils is due to natural wind-dust deposits,but the content of Pb in the soils has nearly tripled from about 22 mg/kg to about 52 mg/kg with the process of anthropogenic urbanization and industrialization.We found that the influence of human activities on lead content was closely related to the total primary energy production(10,000 tons of SCE),and the evolution of soil Pb contents in the study area was consis-tent with the Allometric1 model.
基金supported by Medical and Health Technology Project of Shandong Province(202402020509)20 New Universities Funding Project of Jinan(202228121).
文摘Objectives:PI3K plays a pivotal role in the inflammatory response by modulating the production and release of inflammatory factors.Pik3cb is one of the subunits of PI3K,and its specific role in myocardium inflammation remains unelucidated.This study aimed to investigate the role of Pik3cb in the inflammatory response and to elucidate the underlying mechanism.Methods:An inflammation model was established using H9c2 cells treated with LPS and ATP,and Pik3cb expression was evaluated in this model system.Subsequently,an overexpression model was constructed by transfecting cells with a Pik3cb overexpression plasmid,after which the effects of Pik3cb overexpression on the PI3K/AKT and NF-κB/NLRP3 inflammatory signaling pathways were assessed.Results:These analyses revealed that the expression and distribution of Pik3cb were significantly reduced in the LPS/ATP-induced cellular inflammation model group,whereas plasmid-mediated overexpression of Pik3cb significantly inhibited the activation of the PI3K/AKT signaling pathway in response to LPS/ATP stimulation.Additionally,the LPS/ATP-induced activation of the NF-κB/NLRP3 axis was significantly inhibited following Pik3cb overexpression.Conclusion:This study demonstrates that Pik3cb acts as a negative regulator of LPS/ATP-induced inflammation in cardiomyocytes,exerting anti-inflammatory effects by inhibiting the PI3K/AKT/NF-κB/NLRP3 signaling axis.These findings provide a potential therapeutic target for the treatment of myocardial inflammation.
基金the National Natural Science Foundation of China(No.11872312)the Program of Introducing Talents of Discipline to Universities,China(No.BP0719007)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.CX2022002)。
文摘A multi-body dynamic rigid-flexible coupling model of landing gear is established to study the gear walk instability caused by the friction characteristics of the brake disc.After validating the model with the experimental results,the influence of the landing gear structure and braking system parameters on gear walk is further investigated.Among the above factors,the slope of the graph for the friction coefficient of the brake disc and the relative velocity of brake stators and rotors is the most influential factor on gear walk instability.Phase trajectory analysis verifies that gear walk occurs when the coupling of multiple factors causes the system to exhibit an equivalent negative damping trend.To consider a more realistic braking case,a back propagation neural network method is employed to describe the nonlinear behavior of the friction coefficient of the brake disc.With the realistic nonlinear model of the friction coefficient,the maximum error in predicting the braking torque is less than 10%and the effect of the brake disc temperature on gear walk is performed.The results reveal that a more negative friction slope may contribute to a more severe unstable gear walk,and reducing the braking pressure is an effective approach to avoid gear walk,which provides help for future braking system design.
基金supported in part by the National Natural Science Foundation of China under Grant 62271142in part by the Key Research and Development Program of Jiangsu Province BE2023021+2 种基金in part by the Jiangsu Key Research and Development Program Project under Grant BE2023011-2in part by the Young Scholar Funding of Southeast Universityin part by the Fundamental Research Funds for the Central Universities 2242022k60001。
文摘In this paper,we formulate the precoding problem of integrated sensing and communication(ISAC)waveform as a non-convex quadratically constrained quadratic programming(QCQP),in which the weighted sum of communication multi-user interference(MUI)and the gap between dual-use waveform and ideal radar waveform is minimized with peak-toaverage power ratio(PAPR)constraints.We propose an efficient algorithm based on alternating direction method of multipliers(ADMM),which is able to decouple multiple variables and provide a closed-form solution for each subproblem.In addition,to improve the sensing performance in both spatial and temporal domains,we propose a new criteria to design the ideal radar waveform,in which the beam pattern is made similar to the ideal one and the integrated sidelobe level of the ambiguity function in each target direction is minimized in the region of interest.The limited memory Broyden-Fletcher-Goldfarb-Shanno(LBFGS)algorithm is applied to the design of the ideal radar waveform which works as a reference in the design of the dual-function waveform.Numerical results indicate that the designed dual-function waveform is capable of offering good communication quality of service(QoS)and sensing performance.
