Dear Editor,This letter addresses the resilient distributed cooperative control problem of a virtually coupled train convoy under stochastic disturbances and cyber attacks.The main purpose is to achieve distributed co...Dear Editor,This letter addresses the resilient distributed cooperative control problem of a virtually coupled train convoy under stochastic disturbances and cyber attacks.The main purpose is to achieve distributed coordination of virtually coupled high-speed trains with the prescribed inter-train distance and same cruise velocity.展开更多
Maritime radar and automatic identification systems (AIS), which are essential auxiliary equipment for navigation safety in the shipping industry, have played significant roles in maritime safety supervision. However,...Maritime radar and automatic identification systems (AIS), which are essential auxiliary equipment for navigation safety in the shipping industry, have played significant roles in maritime safety supervision. However, in practical applications, the information obtained by a single device is limited, and it is necessary to integrate the information of maritime radar and AIS messages to achieve better recognition effects. In this study, the D-S evidence theory is used to fusion the two kinds of heterogeneous information: maritime radar images and AIS messages. Firstly, the radar image and AIS message are processed to get the targets of interest in the same coordinate system. Then, the coordinate position and heading of targets are chosen as the indicators for judging target similarity. Finally, a piece of D-S evidence theory based on the information fusion method is proposed to match the radar target and the AIS target of the same ship. Particularly, the effectiveness of the proposed method has been validated and evaluated through several experiments, which proves that such a method is practical in maritime safety supervision.展开更多
Connected automated vehicles(CAVs)serve as a promising enabler for future intelligent transportation systems because of their capabilities in improving traffic efficiency and driving safety,and reducing fuel consumpti...Connected automated vehicles(CAVs)serve as a promising enabler for future intelligent transportation systems because of their capabilities in improving traffic efficiency and driving safety,and reducing fuel consumption and vehicle emissions.A fundamental issue in CAVs is platooning control that empowers a convoy of CAVs to be cooperatively maneuvered with desired longitudinal spacings and identical velocities on roads.This paper addresses the issue of resilient and safe platooning control of CAVs subject to intermittent denial-of-service(DoS)attacks that disrupt vehicle-to-vehicle communications.First,a heterogeneous and uncertain vehicle longitudinal dynamic model is presented to accommodate a variety of uncertainties,including diverse vehicle masses and engine inertial delays,unknown and nonlinear resistance forces,and a dynamic platoon leader.Then,a resilient and safe distributed longitudinal platooning control law is constructed with an aim to preserve simultaneous individual vehicle stability,attack resilience,platoon safety and scalability.Furthermore,a numerically efficient offline design algorithm for determining the desired platoon control law is developed,under which the platoon resilience against DoS attacks can be maximized but the anticipated stability,safety and scalability requirements remain preserved.Finally,extensive numerical experiments are provided to substantiate the efficacy of the proposed platooning method.展开更多
Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shapin...Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shaping is a practical approach to improving sample efficiency by embedding human domain knowledge into the learning process.Existing reward shaping methods for goal-conditioned RL are typically built on distance metrics with a linear and isotropic distribution,which may fail to provide sufficient information about the ever-changing environment with high complexity.This paper proposes a novel magnetic field-based reward shaping(MFRS)method for goal-conditioned RL tasks with dynamic target and obstacles.Inspired by the physical properties of magnets,we consider the target and obstacles as permanent magnets and establish the reward function according to the intensity values of the magnetic field generated by these magnets.The nonlinear and anisotropic distribution of the magnetic field intensity can provide more accessible and conducive information about the optimization landscape,thus introducing a more sophisticated magnetic reward compared to the distance-based setting.Further,we transform our magnetic reward to the form of potential-based reward shaping by learning a secondary potential function concurrently to ensure the optimal policy invariance of our method.Experiments results in both simulated and real-world robotic manipulation tasks demonstrate that MFRS outperforms relevant existing methods and effectively improves the sample efficiency of RL algorithms in goal-conditioned tasks with various dynamics of the target and obstacles.展开更多
The prediction of wheel/rail rolling contact fatigue(RCF)crack initiation during railway operations is an important task.Since RCF crack evolution is influenced by many factors,its prediction process is complex.This p...The prediction of wheel/rail rolling contact fatigue(RCF)crack initiation during railway operations is an important task.Since RCF crack evolution is influenced by many factors,its prediction process is complex.This paper reviews the existing approaches to predict RCF crack initiation.The crack initiation region is predicted by the shakedown map.By combining the shakedown map with various initiation criteria and the critical plane method,the crack initiation life is calculated.The classification,methodologies,theories and applications of these approaches are included in this paper.The advantages and limitations of these methods are analyzed to provide recommendation for RCF crack initiation prediction.This review highlights that wheel/rail dynamic characteristic,complex working conditions,surface defects and wear all affect the RCF crack initiation.The optimal selection of criteria is essential in the crack initiation prediction.Based on the research gap regarding the challenging process of crack initiation prediction detailed in this review,a proposed prediction process of RCF crack initiation is proposed to achieve a more accurate result.展开更多
Brakes in railway trains have a variety of forms such as air brake,eddy current brake and aerodynamic brake.Their primary functions areto slow down and stoptrains,so asto ensure safe and efficient train movement.Brake...Brakes in railway trains have a variety of forms such as air brake,eddy current brake and aerodynamic brake.Their primary functions areto slow down and stoptrains,so asto ensure safe and efficient train movement.Brakes are indispensable and safety-critical systems for all types of railway trains including passenger(high-speed,metro,tram,etc.)and freight(heavy-haul,intermodal,etc.)trains.Safe and efficient railway operations require a good understanding of brakes from various parties including drivers,maintenance crews,manufacturers,and design engineers.Research helps to expand and deepen the knowledge about railway train brakes.Brake modelling and simulation date back to the pre-digital age.However,it remains a challenging topic to today due to many reasons including their nonlinear dynamic nature,complex devices,and the limits regarding parameter determination.展开更多
[Objectives]To regulate the quality of Wanjinxiang Shushuang Ointment through simultaneously quantifying menthol,camphor,1,8-cineole,linalool,borneol and caryophyllene oxide by QAMS(quantitative analysis of multi-comp...[Objectives]To regulate the quality of Wanjinxiang Shushuang Ointment through simultaneously quantifying menthol,camphor,1,8-cineole,linalool,borneol and caryophyllene oxide by QAMS(quantitative analysis of multi-components by single-marker).[Methods]The method was performed using an Agilent DB-WAX(30 m×0.32 mm,0.25μm)polyethylene glycol chromatographic column;with nitrogen employed as a carrier gas.The constant pressure was 4.73 psi;and the injection temperature was 240℃,with a shunt ratio:of 10:1;The hydrogen flame ion detector with a detector temperature of 240℃;the injection volume was 0.3μL.To verify the accuracy and applicability of QAMS,the results were compared with those obtained using the internal standard method(naphthalene).[Results]In Wanjinxiang Shushuang Ointment,menthol,camphor,1,8-cineole,linalool,borneol,caryophyllene oxide and naphthalene were well separated by the same chromatography with good linearity in their respective ranges(R≥0.9992).The average recoveries were 99.66%,101.03%,98.07%,98.24%,101.39%,and 103.39%with RSD s of 0.69%,1.52%,1.25%,1.94%,1.44%,and 2.74%,respectively.The QAMS is similar to the internal standard method.[Conclusions]This simple,accurate method with high precision,separation and reproducibility can serve as a reference for the quality control of Wanjinxiang Shushuang Ointment.展开更多
Background:To investigate the effect of fatigue on the short-term prognosis of young and middle-aged patients with coronary heart disease(CHD).Methods:A cross-sectional,observational survey was distributed at a tertia...Background:To investigate the effect of fatigue on the short-term prognosis of young and middle-aged patients with coronary heart disease(CHD).Methods:A cross-sectional,observational survey was distributed at a tertiary hospital in Suzhou,China.Patients were assessed for fatigue and their prognosis was assessed at 3 and 6 months after discharge.General Information Questionnaire,Fatigue Scale and Seattle Angina Questionnaire(SAQ)were used for the survey.The Cox proportional hazard model was used to analyze the impact of fatigue on the occurrence of major adverse cardiac events(MACEs)at 3 and 6 months after discharge.Multiple linear regression models were used to analyze the effect of fatigue on health-related quality of life(HRQoL)at 3 and 6 months after discharge.Results:199 patients were followed up with in the end.43 patients(21.6%)with MACE three months after discharge had a total SAQ score of(399.76±39.61).The overall SAQ score was(425.14±22.66)and 52 patients(26.1%)experienced MACE six months after discharge.Fatigue was identified as a risk factor for MACE 6 months after discharge by the Cox proportional hazard model(HR=2.939,95%CI:0.177~0.655,P=0.001)and as an independent risk factor for quality of life 3 and 6 months after discharge by multiple linear regression(P<0.001).Conclusions:In individuals who are young or middle-aged and have coronary heart disease,fatigue is a risk factor for the short-term prognosis.It is advised that clinical professionals prioritize patient fatigue assessment and improve management of fatigue symptoms.展开更多
Objective:To examine the present state of fatigue in young and middle-aged patients with coronary heart disease(CHD)and to identify the elements that may be affecting it.Methods:From December 2020 to June 2021,240 you...Objective:To examine the present state of fatigue in young and middle-aged patients with coronary heart disease(CHD)and to identify the elements that may be affecting it.Methods:From December 2020 to June 2021,240 young and middle-aged patients with CHD who were being treated in the cardiology department of a tertiary care hospital in Suzhou were chosen using a convenience sampling method in order to gather data on the patients’sociodemographic status,fatigue,social support,and stress.Results:Of the 240 disseminated questionnaires,220 valid responses were returned,resulting in an effective recovery rate of 91.67%.The frequency of exhaustion was 51.8%,and the fatigue score was(5.27±2.77).The stress score was(11.15±3.36),while the overall social support score was(39.13±4.72).Binary logistic regression analysis indicated that age,exercise,staying up late,stress,social support,high-sensitivity troponin T,high-density lipoprotein,and ejection fraction were independent risk factors for fatigue in young and middle-aged patients with CHD(P<0.05).Conclusions:Fatigue is more prevalent in young and middle-aged patients with CHD.Clinical nurses can create a unique management plan for patients based on their lifestyle and behavioral patterns,stress levels,social support,and clinical signs to reduce fatigue.展开更多
AIM:To investigate the antiproliferative activity of cinobufacini on human hepatocellular carcinoma HepG2 cells and the possible mechanism of its action.METHODS:HepG2 cells were treated with different concentrations o...AIM:To investigate the antiproliferative activity of cinobufacini on human hepatocellular carcinoma HepG2 cells and the possible mechanism of its action.METHODS:HepG2 cells were treated with different concentrations of cinobufacini.Cell viability was measured by methylthiazolyl tetrazolium(MTT) assay.Cell cycledistribution was analyzed by flow cytometry(FCM).Cytoskeletal and nuclear alterations were observed by fluorescein isothiocyanate-phalloidin and DAPI staining under a laser scanning confocal microscope.Changes in morphology and ultrastructure of cells were detected by atomic force microscopy(AFM) at the nanoscale level.RESULTS:MTT assay indicated that cinobufacini significantly inhibited the viability of HepG2 cells in a dosedependent manner.With the concentration of cinobufacini increasing from 0 to 0.10 mg/m L,the cell viability decreased from 74.9% ± 2.7% to 49.41% ± 2.2% and 39.24% ± 2.1%(P < 0.05).FCM analysis demonstrated cell cycle arrest at S phase induced by cinobufacini.The immunofluorescence studies of cytoskeletal and nuclear morphology showed that after cinobufacini treatment,the regular reorganization of actin filaments in HepG2 cells become chaotic,while the nuclei were not damaged seriously.Additionally,high-resolution AFM imaging revealed that cell morphology and ultrastructure changed a lot after treatment with cinobufacini.It appeared as significant shrinkage and deep pores in the cell membrane,with larger particles and a rougher cell surface.CONCLUSION:Cinobufacini inhibits the viability of HepG2 cells via cytoskeletal destruction and cell membrane toxicity.展开更多
Whole trip longitudinal dynamics and energy analysis of heavy haul trains are required by operators and manufacturers to enable optimisation of train controls and rolling stock components. A new technology named train...Whole trip longitudinal dynamics and energy analysis of heavy haul trains are required by operators and manufacturers to enable optimisation of train controls and rolling stock components. A new technology named train dynamics and energy analyser/train simulator(TDEAS)has been developed by the State Key Laboratory of Traction Power in China to perform detailed whole trip longitudinal train dynamics and energy analyses. Facilitated by a controller user interface and a graphic user interface, the TDEAS can also be used as a train driving simulator. This paper elaborates the modelling of three primary parts in the TDEAS, namely wagon connection systems, air brake systems and train energy components. TDEAS uses advanced wedge-spring draft gear models that can simulate a wider spectrum of friction draft gear behaviour. An effective and efficient air brake model that can simulate air brake systems in various train configurations has been integrated. In addition, TDEAS simulates the train energy on the basis of a detailed longitudinal train dynamics simulation, which enables a further perspective of the train energy composition and the overall energy consumption.To demonstrate the validity of the TDEAS, a case study was carried out on a 120-km-long Chinese railway. The results show that the employment of electric locomotives with regenerative braking could bring considerable energy benefits. Nearly 40 % of the locomotive energy usage could be collected from the dynamic brake system. Most of tractive energy was dissipated by propulsion resistance that accounted for 42.48 % of the total energy. Only a small amount of tractive energy was dissipated by curving resistance, air brake and draft gear systems.展开更多
AIM To investigate indications and outcomes of endoscopic retrograde cholangiopancreatography(ERCP) in cirrhotics, especially adverse events. Patients with cirrhosis undergoing ERCP are believed to have increased risk...AIM To investigate indications and outcomes of endoscopic retrograde cholangiopancreatography(ERCP) in cirrhotics, especially adverse events. Patients with cirrhosis undergoing ERCP are believed to have increased risk. However, there is a paucity of literature describing the indications and outcomes of ERCP procedures in patients with cirrhosis, especially focusing on adverse events.METHODS We performed a systematic appraisal of major literature databases, including PubMed and EMBASE, with a manual search of literature from their inception until April 2017.RESULTS A total of 6,505 patients from 15 studies were analyzed(male ratio 59%, mean age 59 years), 11% with alcoholic and 89% with non-alcoholic cirrhosis, with 56.2% Child-Pugh class A, and 43.8% class B or C. Indications for ERCP included choledocholithiasis 60.9%, biliary strictures 26.2%, gallstone pancreatitis 21.1% and cholangitis 15.5%. Types of interventions included endoscopic sphincterotomy 52.7%, biliary stenting 16.7% and biliary dilation 4.6%. Individual adverse events included hemorrhage in 4.58%(95%CI: 2.77-6.75%, I^2 = 85.9%), post-ERCP pancreatitis(PEP) in 3.68%(95%CI: 1.83-6.00%, I^2 = 89.5%), cholangitis in 1.93%(95%CI: 0.63-3.71%, I^2 = 87.1%) and perforation in 0.00%(95%CI: 0.00-0.23%, I^2 = 37.8%). Six studies were used for comparison of ERCPrelated complications in cirrhosis vs non-cirrhosis, which showed higher overall rates of complications in cirrhosis patients with pooled OR of 1.63(95%CI: 1.27-2.09, I2 = 65%): higher rates of hemorrhage with OR of 2.05(95%CI: 1.62-2.58, I^2 = 2.1%) and PEP with OR of 1.33(95%CI: 1.04-1.70, I2=65%), but similar cholangitis rates with OR of 1.23(95%CI: 0.67-2.26, I^2 = 44.3%).CONCLUSION There is an overall higher rate of adverse events related to ERCP in patients with cirrhosis, especially hemorrhage and PEP. A thorough risk/benefit assessment should be performed prior to undertaking ERCP in patients with cirrhosis.展开更多
Support vector machines(SVMs) have been extensively studied and have shown remarkable success in many applications.A new family of twice continuously differentiable piecewise smooth functions are used to smooth the ob...Support vector machines(SVMs) have been extensively studied and have shown remarkable success in many applications.A new family of twice continuously differentiable piecewise smooth functions are used to smooth the objective function of unconstrained SVMs. The three-order piecewise smooth support vector machine(TPWSSVMd) is proposed. The piecewise functions can get higher and higher approximation accuracy as required with the increase of parameter d. The global convergence proof of TPWSSVMdis given with the rough set theory. TPWSSVMdcan efficiently handle large scale and high dimensional problems. Numerical results demonstrate TPWSSVMdhas better classification performance and learning efficiency than other competitive baselines.展开更多
Objective:To investigate the percutaneous penetration enhancement effect of essential oil from Zanthoxylum bungeanum Maxim.(Z.bungeanum oil)on active components in externally-applied traditional Chinese medicines.Meth...Objective:To investigate the percutaneous penetration enhancement effect of essential oil from Zanthoxylum bungeanum Maxim.(Z.bungeanum oil)on active components in externally-applied traditional Chinese medicines.Methods:Five model drugs,geniposide,puerarin,ferulic acid,tetramethylpyrazine,and osthole,were chosen based on their lipophilicity and tested using in vitro transdermal permeation studies consisting of Franz diffusion cells and full thickness rat abdominal skin.Scanning electron microscopy was employed to observe the morphological changes of rat skin tissue after treatment with Z.bungeanum oil.The molecular interactions between the oil and the polar head groups in stratum corneum(SC)lipids were monitored using molecular dynamic simulation,and the SC/vehicle partition coefficients and saturation solubilities of the selected model drugs treated with and without the oil were also determined to ascertain its mechanisms of action.Results:As oil concentration increased,the log ERflow trended toward a negative linear relationship with the lipophilicity of drugs.After treatment with Z.bungeanum oil,a mild lifting up and wrinkle on the SC surface were observed,and appeared to become more pronounced as oil concentration increased.There was no significant difference between the control and the Z.bungeanum oil at different concentrations in terms of saturation solubility of GP,while saturation solubilities of the 4 other drugs gradually increased as oil concentration increased.The oxygen-containing constituents in Z.bungeanum oil,such as terpinen-4-ol and 1,8-cineole,which accounted for 57.95%of total oil,could form stable hydrogen bonds with the polar head group of ceramide 3.Conclusion:Z.bungeanum oil facilitated transdermal permeation of drugs with different lipophilicity,including the extremely hydrophilic and lipophilic drugs,whereas it exhibited greater enhancement activity for strongly hydrophilic drugs.The mechanisms of transdermal permeation enhancement by the oil could be explained with SC/vehicle partition coefficient,saturation solubility,and the interactions with SC lipids.展开更多
AIM:To detect the expression of huCdc7 in colorectal cancer.METHODS:The mRNA and protein expression of huCdc7 in 39 colorectal cancer tissue specimens and matched tumor-adjacent normal colorectal tissue specimens was ...AIM:To detect the expression of huCdc7 in colorectal cancer.METHODS:The mRNA and protein expression of huCdc7 in 39 colorectal cancer tissue specimens and matched tumor-adjacent normal colorectal tissue specimens was detected by reverse transcription-polymerase chain reaction and immunohistochemistry,respectively.RESULTS:The relative expression level of huCdc7 mRNA in colorectal cancer was significantly higher than that in tumor-adjacent normal colorectal tissues(0.03675 ± 1.00 vs 0.01199 ± 0.44,P < 0.05).huCdc7-positive cells displayed brown granules in the nucleus.Tumor tissues contained many huCdc7-positive cells,whereas normal colorectal tissues contained very few positive cells.CONCLUSION:huCdc7 may play an important role in the development and progression of colorectal cancer.展开更多
Objective:To investigate the percutaneous penetration effect of essential oil of mint from Mentha haplocalyx Briq.on the complex active components in Chinese herbal external preparations,and assess its toxicity on the...Objective:To investigate the percutaneous penetration effect of essential oil of mint from Mentha haplocalyx Briq.on the complex active components in Chinese herbal external preparations,and assess its toxicity on the skin cells.Methods:The cytotoxicity of mint oil on HaCaT keratinocytes and CCC-ESF-1 fibroblasts was measured using an MTT assay.Five model drugs with a wide range of lipophilicity,namely osthole,tetramethylpyrazine,ferulic acid,puerarin,and geniposide,were tested using in vitro permeation studies to investigate the percutaneous penetration enhancement effect of mint oil.Secondary structure alterations of skin stratum corneum(SC)were measured using Fourier transform infrared spectroscopy(FTIR).Saturation solubilities and SC/vehicle partition coefficients of the five model drugs with and without mint oil were also determined to understand the potential mechanisms of the essential oil.Results:Half maximal inhibitory concentration(IC50)values of mint oil were significantly higher in HaCaT and CCC-ESF-1 cell lines than values in the well-established and standard penetration enhancer Azone.Conclusions:Mint oil at proper concentration could effectively facilitate percutaneous penetration of both lipophilic and hydrophilic drugs,and exhibit higher efficiency for moderate hydrophilic drugs.Mechanisms of penetration enhancement by mint oil could be explained with saturation solubility,SC/vehicle partition coefficient and the secondary structure change of SC.展开更多
Objective:To establish a basis for Angelica Sinensis Radix(ASR)as a dietary supplement for colorectal cancer chemoprevention,the effect of co-existent components in supercritical fluid extract(SFE)of ASR on the pharma...Objective:To establish a basis for Angelica Sinensis Radix(ASR)as a dietary supplement for colorectal cancer chemoprevention,the effect of co-existent components in supercritical fluid extract(SFE)of ASR on the pharmacokinetics of Z-ligustilide after oral administration was investigated in vitro and in vivo.Methods:Incubation in gastrointestinal contents and incubation in rat liver tissue homogenates post-mitochondrial supernatant(PMS)experiments were used to study changes in the levels of Z-ligustilide in vitro.Results:Within 4 hours,the level of Z-ligustilide in SFE declined at a slower rate than in its pure form.Clearance of Z-ligustilide after administration in its pure form was significantly slower than that of SFE of ASR(CL,0.96±0.16 mL·min/kg versus 1.24±0.21 mL·min/kg P<0.05;AUC,243.37±16.84 versus 176.69±12.59 mg·min/L).Conclusion:These phenomena may be attributed to the interactions between the co-existent components in SFE of ASR and Z-ligustilide enhancing the stability of Z-ligustilide.These results suggest that the bioavailability of Z-ligustilide in SFE of ASR is improved.However,stabilization of plasma concentration was not sustained,so that the efficacy of active components could not be maintained.Thus,further processing of SFE of ASR is required.展开更多
基金the National Natural Science Foundation of China(62303240)the Natural Science Foundation of Jiangsu Province of China(BK20230356)+1 种基金the Natural Science Research Start-Up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(NY222033)the Natural Science Foundation for Colleges and Universities in Jiangsu Province(22KJB120001)。
文摘Dear Editor,This letter addresses the resilient distributed cooperative control problem of a virtually coupled train convoy under stochastic disturbances and cyber attacks.The main purpose is to achieve distributed coordination of virtually coupled high-speed trains with the prescribed inter-train distance and same cruise velocity.
文摘Maritime radar and automatic identification systems (AIS), which are essential auxiliary equipment for navigation safety in the shipping industry, have played significant roles in maritime safety supervision. However, in practical applications, the information obtained by a single device is limited, and it is necessary to integrate the information of maritime radar and AIS messages to achieve better recognition effects. In this study, the D-S evidence theory is used to fusion the two kinds of heterogeneous information: maritime radar images and AIS messages. Firstly, the radar image and AIS message are processed to get the targets of interest in the same coordinate system. Then, the coordinate position and heading of targets are chosen as the indicators for judging target similarity. Finally, a piece of D-S evidence theory based on the information fusion method is proposed to match the radar target and the AIS target of the same ship. Particularly, the effectiveness of the proposed method has been validated and evaluated through several experiments, which proves that such a method is practical in maritime safety supervision.
基金supported in part by Australian Research Council Discovery Early Career Researcher Award(DE210100273)。
文摘Connected automated vehicles(CAVs)serve as a promising enabler for future intelligent transportation systems because of their capabilities in improving traffic efficiency and driving safety,and reducing fuel consumption and vehicle emissions.A fundamental issue in CAVs is platooning control that empowers a convoy of CAVs to be cooperatively maneuvered with desired longitudinal spacings and identical velocities on roads.This paper addresses the issue of resilient and safe platooning control of CAVs subject to intermittent denial-of-service(DoS)attacks that disrupt vehicle-to-vehicle communications.First,a heterogeneous and uncertain vehicle longitudinal dynamic model is presented to accommodate a variety of uncertainties,including diverse vehicle masses and engine inertial delays,unknown and nonlinear resistance forces,and a dynamic platoon leader.Then,a resilient and safe distributed longitudinal platooning control law is constructed with an aim to preserve simultaneous individual vehicle stability,attack resilience,platoon safety and scalability.Furthermore,a numerically efficient offline design algorithm for determining the desired platoon control law is developed,under which the platoon resilience against DoS attacks can be maximized but the anticipated stability,safety and scalability requirements remain preserved.Finally,extensive numerical experiments are provided to substantiate the efficacy of the proposed platooning method.
基金supported in part by the National Natural Science Foundation of China(62006111,62073160)the Natural Science Foundation of Jiangsu Province of China(BK20200330)。
文摘Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shaping is a practical approach to improving sample efficiency by embedding human domain knowledge into the learning process.Existing reward shaping methods for goal-conditioned RL are typically built on distance metrics with a linear and isotropic distribution,which may fail to provide sufficient information about the ever-changing environment with high complexity.This paper proposes a novel magnetic field-based reward shaping(MFRS)method for goal-conditioned RL tasks with dynamic target and obstacles.Inspired by the physical properties of magnets,we consider the target and obstacles as permanent magnets and establish the reward function according to the intensity values of the magnetic field generated by these magnets.The nonlinear and anisotropic distribution of the magnetic field intensity can provide more accessible and conducive information about the optimization landscape,thus introducing a more sophisticated magnetic reward compared to the distance-based setting.Further,we transform our magnetic reward to the form of potential-based reward shaping by learning a secondary potential function concurrently to ensure the optimal policy invariance of our method.Experiments results in both simulated and real-world robotic manipulation tasks demonstrate that MFRS outperforms relevant existing methods and effectively improves the sample efficiency of RL algorithms in goal-conditioned tasks with various dynamics of the target and obstacles.
基金supported by National Natural Science Foundation of China(Nos.52202510,U21A20167,52272443 and 51975489)Autonomous Research Project of State Key Laboratory(Nos.2020TPL-T10 and 2022TPL-T04)+1 种基金For a scholarship to S.Y.Zhang,under the State Scholarship Fund of the China Scholarship Council(CSC)(No.202007000128)to pursue study in the Central Queensland University as a cotutelle PhD Student.Dr.Qing Wu is the recipient of an Australian Research Council Discovery Early Career Award(Project Number DE210100273)funded by the Australian Government.
文摘The prediction of wheel/rail rolling contact fatigue(RCF)crack initiation during railway operations is an important task.Since RCF crack evolution is influenced by many factors,its prediction process is complex.This paper reviews the existing approaches to predict RCF crack initiation.The crack initiation region is predicted by the shakedown map.By combining the shakedown map with various initiation criteria and the critical plane method,the crack initiation life is calculated.The classification,methodologies,theories and applications of these approaches are included in this paper.The advantages and limitations of these methods are analyzed to provide recommendation for RCF crack initiation prediction.This review highlights that wheel/rail dynamic characteristic,complex working conditions,surface defects and wear all affect the RCF crack initiation.The optimal selection of criteria is essential in the crack initiation prediction.Based on the research gap regarding the challenging process of crack initiation prediction detailed in this review,a proposed prediction process of RCF crack initiation is proposed to achieve a more accurate result.
文摘Brakes in railway trains have a variety of forms such as air brake,eddy current brake and aerodynamic brake.Their primary functions areto slow down and stoptrains,so asto ensure safe and efficient train movement.Brakes are indispensable and safety-critical systems for all types of railway trains including passenger(high-speed,metro,tram,etc.)and freight(heavy-haul,intermodal,etc.)trains.Safe and efficient railway operations require a good understanding of brakes from various parties including drivers,maintenance crews,manufacturers,and design engineers.Research helps to expand and deepen the knowledge about railway train brakes.Brake modelling and simulation date back to the pre-digital age.However,it remains a challenging topic to today due to many reasons including their nonlinear dynamic nature,complex devices,and the limits regarding parameter determination.
基金Supported by Projects of Guizhou Provincial Department of Education-Growth Program of Young Scientific and Technological Talents in Guizhou Ordinary Higher Education Institutions(QJHKY[2022]264)Rolling Support for Provincial University Research Platform Team Projects(QJJ[2022]010).
文摘[Objectives]To regulate the quality of Wanjinxiang Shushuang Ointment through simultaneously quantifying menthol,camphor,1,8-cineole,linalool,borneol and caryophyllene oxide by QAMS(quantitative analysis of multi-components by single-marker).[Methods]The method was performed using an Agilent DB-WAX(30 m×0.32 mm,0.25μm)polyethylene glycol chromatographic column;with nitrogen employed as a carrier gas.The constant pressure was 4.73 psi;and the injection temperature was 240℃,with a shunt ratio:of 10:1;The hydrogen flame ion detector with a detector temperature of 240℃;the injection volume was 0.3μL.To verify the accuracy and applicability of QAMS,the results were compared with those obtained using the internal standard method(naphthalene).[Results]In Wanjinxiang Shushuang Ointment,menthol,camphor,1,8-cineole,linalool,borneol,caryophyllene oxide and naphthalene were well separated by the same chromatography with good linearity in their respective ranges(R≥0.9992).The average recoveries were 99.66%,101.03%,98.07%,98.24%,101.39%,and 103.39%with RSD s of 0.69%,1.52%,1.25%,1.94%,1.44%,and 2.74%,respectively.The QAMS is similar to the internal standard method.[Conclusions]This simple,accurate method with high precision,separation and reproducibility can serve as a reference for the quality control of Wanjinxiang Shushuang Ointment.
基金supported by Suzhou Science and Technology Development Plan Project (grant number:sys2018018).
文摘Background:To investigate the effect of fatigue on the short-term prognosis of young and middle-aged patients with coronary heart disease(CHD).Methods:A cross-sectional,observational survey was distributed at a tertiary hospital in Suzhou,China.Patients were assessed for fatigue and their prognosis was assessed at 3 and 6 months after discharge.General Information Questionnaire,Fatigue Scale and Seattle Angina Questionnaire(SAQ)were used for the survey.The Cox proportional hazard model was used to analyze the impact of fatigue on the occurrence of major adverse cardiac events(MACEs)at 3 and 6 months after discharge.Multiple linear regression models were used to analyze the effect of fatigue on health-related quality of life(HRQoL)at 3 and 6 months after discharge.Results:199 patients were followed up with in the end.43 patients(21.6%)with MACE three months after discharge had a total SAQ score of(399.76±39.61).The overall SAQ score was(425.14±22.66)and 52 patients(26.1%)experienced MACE six months after discharge.Fatigue was identified as a risk factor for MACE 6 months after discharge by the Cox proportional hazard model(HR=2.939,95%CI:0.177~0.655,P=0.001)and as an independent risk factor for quality of life 3 and 6 months after discharge by multiple linear regression(P<0.001).Conclusions:In individuals who are young or middle-aged and have coronary heart disease,fatigue is a risk factor for the short-term prognosis.It is advised that clinical professionals prioritize patient fatigue assessment and improve management of fatigue symptoms.
基金This study received support from the Suzhou Science and Technology Development Plan Livelihood Technology Project(No.sys2018018)the Soochow University Medical Department Scientific Research Project(No.2021YXBKWKY044)。
文摘Objective:To examine the present state of fatigue in young and middle-aged patients with coronary heart disease(CHD)and to identify the elements that may be affecting it.Methods:From December 2020 to June 2021,240 young and middle-aged patients with CHD who were being treated in the cardiology department of a tertiary care hospital in Suzhou were chosen using a convenience sampling method in order to gather data on the patients’sociodemographic status,fatigue,social support,and stress.Results:Of the 240 disseminated questionnaires,220 valid responses were returned,resulting in an effective recovery rate of 91.67%.The frequency of exhaustion was 51.8%,and the fatigue score was(5.27±2.77).The stress score was(11.15±3.36),while the overall social support score was(39.13±4.72).Binary logistic regression analysis indicated that age,exercise,staying up late,stress,social support,high-sensitivity troponin T,high-density lipoprotein,and ejection fraction were independent risk factors for fatigue in young and middle-aged patients with CHD(P<0.05).Conclusions:Fatigue is more prevalent in young and middle-aged patients with CHD.Clinical nurses can create a unique management plan for patients based on their lifestyle and behavioral patterns,stress levels,social support,and clinical signs to reduce fatigue.
基金ACKNOWLEDGMENTS This research was supported by the Major State Basic Research Development Program of China （973 Program, Noso 2006GB504005 and 2009CB941700）, the National Natural Science Foundation of China （No. 30872765） and the Basic Research Key Program of Shanghai （10]C1410800）. Shi-Wei Duan is sponsored partly by the K. C. Wong Magna Fund of Ningbo University. Wethank Dr Ching-Ling Chen for kind suggestions regarding English in drafting this paper.
文摘AIM:To investigate the antiproliferative activity of cinobufacini on human hepatocellular carcinoma HepG2 cells and the possible mechanism of its action.METHODS:HepG2 cells were treated with different concentrations of cinobufacini.Cell viability was measured by methylthiazolyl tetrazolium(MTT) assay.Cell cycledistribution was analyzed by flow cytometry(FCM).Cytoskeletal and nuclear alterations were observed by fluorescein isothiocyanate-phalloidin and DAPI staining under a laser scanning confocal microscope.Changes in morphology and ultrastructure of cells were detected by atomic force microscopy(AFM) at the nanoscale level.RESULTS:MTT assay indicated that cinobufacini significantly inhibited the viability of HepG2 cells in a dosedependent manner.With the concentration of cinobufacini increasing from 0 to 0.10 mg/m L,the cell viability decreased from 74.9% ± 2.7% to 49.41% ± 2.2% and 39.24% ± 2.1%(P < 0.05).FCM analysis demonstrated cell cycle arrest at S phase induced by cinobufacini.The immunofluorescence studies of cytoskeletal and nuclear morphology showed that after cinobufacini treatment,the regular reorganization of actin filaments in HepG2 cells become chaotic,while the nuclei were not damaged seriously.Additionally,high-resolution AFM imaging revealed that cell morphology and ultrastructure changed a lot after treatment with cinobufacini.It appeared as significant shrinkage and deep pores in the cell membrane,with larger particles and a rougher cell surface.CONCLUSION:Cinobufacini inhibits the viability of HepG2 cells via cytoskeletal destruction and cell membrane toxicity.
文摘Whole trip longitudinal dynamics and energy analysis of heavy haul trains are required by operators and manufacturers to enable optimisation of train controls and rolling stock components. A new technology named train dynamics and energy analyser/train simulator(TDEAS)has been developed by the State Key Laboratory of Traction Power in China to perform detailed whole trip longitudinal train dynamics and energy analyses. Facilitated by a controller user interface and a graphic user interface, the TDEAS can also be used as a train driving simulator. This paper elaborates the modelling of three primary parts in the TDEAS, namely wagon connection systems, air brake systems and train energy components. TDEAS uses advanced wedge-spring draft gear models that can simulate a wider spectrum of friction draft gear behaviour. An effective and efficient air brake model that can simulate air brake systems in various train configurations has been integrated. In addition, TDEAS simulates the train energy on the basis of a detailed longitudinal train dynamics simulation, which enables a further perspective of the train energy composition and the overall energy consumption.To demonstrate the validity of the TDEAS, a case study was carried out on a 120-km-long Chinese railway. The results show that the employment of electric locomotives with regenerative braking could bring considerable energy benefits. Nearly 40 % of the locomotive energy usage could be collected from the dynamic brake system. Most of tractive energy was dissipated by propulsion resistance that accounted for 42.48 % of the total energy. Only a small amount of tractive energy was dissipated by curving resistance, air brake and draft gear systems.
文摘AIM To investigate indications and outcomes of endoscopic retrograde cholangiopancreatography(ERCP) in cirrhotics, especially adverse events. Patients with cirrhosis undergoing ERCP are believed to have increased risk. However, there is a paucity of literature describing the indications and outcomes of ERCP procedures in patients with cirrhosis, especially focusing on adverse events.METHODS We performed a systematic appraisal of major literature databases, including PubMed and EMBASE, with a manual search of literature from their inception until April 2017.RESULTS A total of 6,505 patients from 15 studies were analyzed(male ratio 59%, mean age 59 years), 11% with alcoholic and 89% with non-alcoholic cirrhosis, with 56.2% Child-Pugh class A, and 43.8% class B or C. Indications for ERCP included choledocholithiasis 60.9%, biliary strictures 26.2%, gallstone pancreatitis 21.1% and cholangitis 15.5%. Types of interventions included endoscopic sphincterotomy 52.7%, biliary stenting 16.7% and biliary dilation 4.6%. Individual adverse events included hemorrhage in 4.58%(95%CI: 2.77-6.75%, I^2 = 85.9%), post-ERCP pancreatitis(PEP) in 3.68%(95%CI: 1.83-6.00%, I^2 = 89.5%), cholangitis in 1.93%(95%CI: 0.63-3.71%, I^2 = 87.1%) and perforation in 0.00%(95%CI: 0.00-0.23%, I^2 = 37.8%). Six studies were used for comparison of ERCPrelated complications in cirrhosis vs non-cirrhosis, which showed higher overall rates of complications in cirrhosis patients with pooled OR of 1.63(95%CI: 1.27-2.09, I2 = 65%): higher rates of hemorrhage with OR of 2.05(95%CI: 1.62-2.58, I^2 = 2.1%) and PEP with OR of 1.33(95%CI: 1.04-1.70, I2=65%), but similar cholangitis rates with OR of 1.23(95%CI: 0.67-2.26, I^2 = 44.3%).CONCLUSION There is an overall higher rate of adverse events related to ERCP in patients with cirrhosis, especially hemorrhage and PEP. A thorough risk/benefit assessment should be performed prior to undertaking ERCP in patients with cirrhosis.
基金supported by the National Natural Science Foundation of China(6110016561100231+6 种基金5120530961472307)the Natural Science Foundation of Shaanxi Province(2012JQ80442014JM83132010JQ8004)the Foundation of Education Department of Shaanxi Province(2013JK1096)the New Star Team of Xi’an University of Posts and Telecommunications
文摘Support vector machines(SVMs) have been extensively studied and have shown remarkable success in many applications.A new family of twice continuously differentiable piecewise smooth functions are used to smooth the objective function of unconstrained SVMs. The three-order piecewise smooth support vector machine(TPWSSVMd) is proposed. The piecewise functions can get higher and higher approximation accuracy as required with the increase of parameter d. The global convergence proof of TPWSSVMdis given with the rough set theory. TPWSSVMdcan efficiently handle large scale and high dimensional problems. Numerical results demonstrate TPWSSVMdhas better classification performance and learning efficiency than other competitive baselines.
基金National Natural Science Foundation of China(No.81473365)Postgraduate Project of Beijing University of Chinese Medicine(No.2016-JYB-XS095)The authors also thank the Innovative Research Team of Beijing University of Chinese Medicine(No.2011-CXTD-13)for its financial support.
文摘Objective:To investigate the percutaneous penetration enhancement effect of essential oil from Zanthoxylum bungeanum Maxim.(Z.bungeanum oil)on active components in externally-applied traditional Chinese medicines.Methods:Five model drugs,geniposide,puerarin,ferulic acid,tetramethylpyrazine,and osthole,were chosen based on their lipophilicity and tested using in vitro transdermal permeation studies consisting of Franz diffusion cells and full thickness rat abdominal skin.Scanning electron microscopy was employed to observe the morphological changes of rat skin tissue after treatment with Z.bungeanum oil.The molecular interactions between the oil and the polar head groups in stratum corneum(SC)lipids were monitored using molecular dynamic simulation,and the SC/vehicle partition coefficients and saturation solubilities of the selected model drugs treated with and without the oil were also determined to ascertain its mechanisms of action.Results:As oil concentration increased,the log ERflow trended toward a negative linear relationship with the lipophilicity of drugs.After treatment with Z.bungeanum oil,a mild lifting up and wrinkle on the SC surface were observed,and appeared to become more pronounced as oil concentration increased.There was no significant difference between the control and the Z.bungeanum oil at different concentrations in terms of saturation solubility of GP,while saturation solubilities of the 4 other drugs gradually increased as oil concentration increased.The oxygen-containing constituents in Z.bungeanum oil,such as terpinen-4-ol and 1,8-cineole,which accounted for 57.95%of total oil,could form stable hydrogen bonds with the polar head group of ceramide 3.Conclusion:Z.bungeanum oil facilitated transdermal permeation of drugs with different lipophilicity,including the extremely hydrophilic and lipophilic drugs,whereas it exhibited greater enhancement activity for strongly hydrophilic drugs.The mechanisms of transdermal permeation enhancement by the oil could be explained with SC/vehicle partition coefficient,saturation solubility,and the interactions with SC lipids.
文摘AIM:To detect the expression of huCdc7 in colorectal cancer.METHODS:The mRNA and protein expression of huCdc7 in 39 colorectal cancer tissue specimens and matched tumor-adjacent normal colorectal tissue specimens was detected by reverse transcription-polymerase chain reaction and immunohistochemistry,respectively.RESULTS:The relative expression level of huCdc7 mRNA in colorectal cancer was significantly higher than that in tumor-adjacent normal colorectal tissues(0.03675 ± 1.00 vs 0.01199 ± 0.44,P < 0.05).huCdc7-positive cells displayed brown granules in the nucleus.Tumor tissues contained many huCdc7-positive cells,whereas normal colorectal tissues contained very few positive cells.CONCLUSION:huCdc7 may play an important role in the development and progression of colorectal cancer.
基金the National Natural Science Foundation of China(No.81473365)the Innovative Research Team in Beijing University of Chinese Medicine(No.2011-CXTD-13).
文摘Objective:To investigate the percutaneous penetration effect of essential oil of mint from Mentha haplocalyx Briq.on the complex active components in Chinese herbal external preparations,and assess its toxicity on the skin cells.Methods:The cytotoxicity of mint oil on HaCaT keratinocytes and CCC-ESF-1 fibroblasts was measured using an MTT assay.Five model drugs with a wide range of lipophilicity,namely osthole,tetramethylpyrazine,ferulic acid,puerarin,and geniposide,were tested using in vitro permeation studies to investigate the percutaneous penetration enhancement effect of mint oil.Secondary structure alterations of skin stratum corneum(SC)were measured using Fourier transform infrared spectroscopy(FTIR).Saturation solubilities and SC/vehicle partition coefficients of the five model drugs with and without mint oil were also determined to understand the potential mechanisms of the essential oil.Results:Half maximal inhibitory concentration(IC50)values of mint oil were significantly higher in HaCaT and CCC-ESF-1 cell lines than values in the well-established and standard penetration enhancer Azone.Conclusions:Mint oil at proper concentration could effectively facilitate percutaneous penetration of both lipophilic and hydrophilic drugs,and exhibit higher efficiency for moderate hydrophilic drugs.Mechanisms of penetration enhancement by mint oil could be explained with saturation solubility,SC/vehicle partition coefficient and the secondary structure change of SC.
基金by the National Natural Science Foundation(No.81073059).
文摘Objective:To establish a basis for Angelica Sinensis Radix(ASR)as a dietary supplement for colorectal cancer chemoprevention,the effect of co-existent components in supercritical fluid extract(SFE)of ASR on the pharmacokinetics of Z-ligustilide after oral administration was investigated in vitro and in vivo.Methods:Incubation in gastrointestinal contents and incubation in rat liver tissue homogenates post-mitochondrial supernatant(PMS)experiments were used to study changes in the levels of Z-ligustilide in vitro.Results:Within 4 hours,the level of Z-ligustilide in SFE declined at a slower rate than in its pure form.Clearance of Z-ligustilide after administration in its pure form was significantly slower than that of SFE of ASR(CL,0.96±0.16 mL·min/kg versus 1.24±0.21 mL·min/kg P<0.05;AUC,243.37±16.84 versus 176.69±12.59 mg·min/L).Conclusion:These phenomena may be attributed to the interactions between the co-existent components in SFE of ASR and Z-ligustilide enhancing the stability of Z-ligustilide.These results suggest that the bioavailability of Z-ligustilide in SFE of ASR is improved.However,stabilization of plasma concentration was not sustained,so that the efficacy of active components could not be maintained.Thus,further processing of SFE of ASR is required.
