Recent advances in the experimental and theoretical study of dynamics of neuronal electrical firing activities are reviewed. Firstly, some experimental phenomena of neuronal irregular firing patterns, especially chaot...Recent advances in the experimental and theoretical study of dynamics of neuronal electrical firing activities are reviewed. Firstly, some experimental phenomena of neuronal irregular firing patterns, especially chaotic and stochastic firing patterns, are presented, and practical nonlinear time analysis methods are introduced to distinguish deterministic and stochastic mechanism in time series. Secondly, the dynamics of electrical firing activities in a single neuron is concerned, namely, fast-slow dynamics analysis for classification and mechanism of various bursting patterns, one- or two-parameter bifurcation analysis for transitions of firing patterns, and stochastic dynamics of firing activities （stochastic and coherence resonances, integer multiple and other firing patterns induced by noise, etc.）. Thirdly, different types of synchronization of coupled neurons with electrical and chemical synapses are discussed. As noise and time delay are inevitable in nervous systems, it is found that noise and time delay may induce or enhance synchronization and change firing patterns of coupled neurons. Noise-induced resonance and spatiotemporal patterns in coupled neuronal networks are also demonstrated. Finally, some prospects are presented for future research. In consequence, the idea and methods of nonlinear dynamics are of great significance in exploration of dynamic processes and physiological functions of nervous systems.展开更多
Emerging sub-synchronous interactions(SSI)in wind-integrated power systems have added intense attention after numerous incidents in the US and China due to the involvement of series compensated transmission lines and ...Emerging sub-synchronous interactions(SSI)in wind-integrated power systems have added intense attention after numerous incidents in the US and China due to the involvement of series compensated transmission lines and power electronics devices.SSI phenomenon occurs when two power system elements exchange energy below the synchro-nous frequency.SSI phenomenon related to wind power plants is one of the most significant challenges to main-taining stability,while SSI phenomenon in practical wind farms,which has been observed recently,has not yet been described on the source of conventional SSI literature.This paper first explains the traditional development of SSI and its classification as given by the IEEE,and then it proposes a classification of SSI according to the current research status,reviews several mitigation techniques and challenges,and discusses analysis techniques for SSI.The paper also describes the effect of the active damping controllers,control scheme parameters,degree of series compensation,and various techniques used in wind power plants(WPPs).In particular,a supplementary damping controller with converter controllers in Doubly Fed Induction Generator based WPPs is briefly pronounced.This paper provides a real-istic viewpoint and a potential outlook for the readers to properly deal with SSI and its mitigation techniques,which can help power engineers for the planning,economical operation,and future expansion of sustainable development.展开更多
This study investigates the dynamical behaviors of nearest neighbor asymmetric coupled systems in a confined space.First, the study derivative analytical stability and synchronization conditions for the asymmetrically...This study investigates the dynamical behaviors of nearest neighbor asymmetric coupled systems in a confined space.First, the study derivative analytical stability and synchronization conditions for the asymmetrically coupled system in an unconfined space, which are then validated through numerical simulations. Simulation results show that asymmetric coupling has a significant impact on synchronization conditions. Moreover, it is observed that irrespective of whether the system is confined, an increase in coupling asymmetry leads to a hastened synchronization pace. Additionally, the study examines the effects of boundaries on the system's collective behaviors via numerical experiments. The presence of boundaries ensures the system's stability and synchronization, and reducing these boundaries can expedite the synchronization process and amplify its effects. Finally, the study reveals that the system's output amplitude exhibits stochastic resonance as the confined boundary size increases.展开更多
The brain neural system is often disturbed by electromagnetic and noise environments, and research on dynamic response of its interaction has received extensive attention. This paper investigates electrical activity o...The brain neural system is often disturbed by electromagnetic and noise environments, and research on dynamic response of its interaction has received extensive attention. This paper investigates electrical activity of Morris-Lecar neural systems exposed to sinusoidal induced electric field(IEF) with random phase generated by electromagnetic effect. By introducing a membrane depolarization model under the effect of random IEF, transition state of firing patterns, including mixed-mode oscillations(MMOs) with layered inter-spike intervals(ISI) and intermittency with a power law distribution in probability density function of ISI, is obtained in a single neuron. Considering the synergistic effects of frequency and noise, coherence resonance is performed by phase noise of IEF under certain parameter conditions. For the neural network without any internal coupling, we demonstrate that synchronous oscillations can be induced by IEF coupling, and suppression of synchronous spiking is achieved effectively by phase noise of IEF. Results of the study enrich the dynamical response to electromagnetic induction and provide insights into mechanisms of noise affecting information coding and transmission in neural systems.展开更多
BACKGROUND Synchronous liver metastasis(SLM)is an indicator of poor prognosis for colorectal cancer(CRC).Nearly 50%of CRC patients develop hepatic metastasis,with 15%-25%of them presenting with SLM.The evaluation of S...BACKGROUND Synchronous liver metastasis(SLM)is an indicator of poor prognosis for colorectal cancer(CRC).Nearly 50%of CRC patients develop hepatic metastasis,with 15%-25%of them presenting with SLM.The evaluation of SLM in CRC is crucial for precise and personalized treatment.It is beneficial to detect its response to chemotherapy and choose an optimal treatment method.AIM To construct prediction models based on magnetic resonance imaging(MRI)-radiomics and clinical parameters to evaluate the chemotherapy response in SLM of CRC.METHODS A total of 102 CRC patients with 223 SLM lesions were identified and divided into disease response(DR)and disease non-response(non-DR)to chemotherapy.After standardizing the MRI images,the volume of interest was delineated and radiomics features were calculated.The MRI-radiomics logistic model was constructed after methods of variance/Mann-Whitney U test,correlation analysis,and least absolute shrinkage and selection operator in feature selecting.The radiomics score was calculated.The receiver operating characteristics curves by the DeLong test were analyzed with MedCalc software to compare the validity of all models.Additionally,the area under curves(AUCs)of DWI,T2WI,and portal phase of contrast-enhanced sequences radiomics model(Ra-DWI,Ra-T2WI,and Ra-portal phase of contrast-enhanced sequences)were calculated.The radiomicsclinical nomogram was generated by combining radiomics features and clinical characteristics of CA19-9 and clinical N staging.RESULTS The AUCs of the MRI-radiomics model were 0.733 and 0.753 for the training(156 lesions with 68 non-DR and 88 DR)and the validation(67 lesions with 29 non-DR and 38 DR)set,respectively.Additionally,the AUCs of the training and the validation set of Ra-DWI were higher than those of Ra-T2WI and Ra-portal phase of contrast-enhanced sequences(training set:0.652 vs 0.628 and 0.633,validation set:0.661 vs 0.575 and 0.543).After chemotherapy,the top four of twelve deltaradiomics features of Ra-DWI in the DR group belonged to gray-level run展开更多
The effect of diversity on dynamics of coupled FitzHugh-Nagumo neurons on complex networks is numerically investigated, where each neuron is subjected to an external subthreshold signal. With the diversity the network...The effect of diversity on dynamics of coupled FitzHugh-Nagumo neurons on complex networks is numerically investigated, where each neuron is subjected to an external subthreshold signal. With the diversity the network is a mixture of excitable and oscillatory neurons, and the diversity is determined by the variance of the system＇s parameter. The complex network is constructed by randomly adding long-range connections （shortcuts） on a nearest-neighbouring coupled one-dimensional chain. Numerical results show that external signals are maximally magnified at an intermediate value of the diversity, as in the case of well-known stochastic resonance, burthermore, the effects of the number of shortcuts and coupled strength on the diversity-induced phenomena are also discussed. These findings exhibit that the diversity may play a constructive role in response to external signal, and highlight the importance of the diversity on such complex networks.展开更多
基金the National Natural Science Foundation of China (10432010,10702002,10772101,10802012)the National High Technology Research and Development Program (2007AA02Z310)
文摘Recent advances in the experimental and theoretical study of dynamics of neuronal electrical firing activities are reviewed. Firstly, some experimental phenomena of neuronal irregular firing patterns, especially chaotic and stochastic firing patterns, are presented, and practical nonlinear time analysis methods are introduced to distinguish deterministic and stochastic mechanism in time series. Secondly, the dynamics of electrical firing activities in a single neuron is concerned, namely, fast-slow dynamics analysis for classification and mechanism of various bursting patterns, one- or two-parameter bifurcation analysis for transitions of firing patterns, and stochastic dynamics of firing activities （stochastic and coherence resonances, integer multiple and other firing patterns induced by noise, etc.）. Thirdly, different types of synchronization of coupled neurons with electrical and chemical synapses are discussed. As noise and time delay are inevitable in nervous systems, it is found that noise and time delay may induce or enhance synchronization and change firing patterns of coupled neurons. Noise-induced resonance and spatiotemporal patterns in coupled neuronal networks are also demonstrated. Finally, some prospects are presented for future research. In consequence, the idea and methods of nonlinear dynamics are of great significance in exploration of dynamic processes and physiological functions of nervous systems.
基金supported financially by the Ministerio de Ciencia e Innovación(Spain)and the European Regional Development Fund,under Research Grant WindSound project(Ref.:PID2021-125278OB-I00).
文摘Emerging sub-synchronous interactions(SSI)in wind-integrated power systems have added intense attention after numerous incidents in the US and China due to the involvement of series compensated transmission lines and power electronics devices.SSI phenomenon occurs when two power system elements exchange energy below the synchro-nous frequency.SSI phenomenon related to wind power plants is one of the most significant challenges to main-taining stability,while SSI phenomenon in practical wind farms,which has been observed recently,has not yet been described on the source of conventional SSI literature.This paper first explains the traditional development of SSI and its classification as given by the IEEE,and then it proposes a classification of SSI according to the current research status,reviews several mitigation techniques and challenges,and discusses analysis techniques for SSI.The paper also describes the effect of the active damping controllers,control scheme parameters,degree of series compensation,and various techniques used in wind power plants(WPPs).In particular,a supplementary damping controller with converter controllers in Doubly Fed Induction Generator based WPPs is briefly pronounced.This paper provides a real-istic viewpoint and a potential outlook for the readers to properly deal with SSI and its mitigation techniques,which can help power engineers for the planning,economical operation,and future expansion of sustainable development.
基金Project supported by the Natural Science Foundation of Shandong Province of China for the Youth (Grant No. ZR2023QA102)。
文摘This study investigates the dynamical behaviors of nearest neighbor asymmetric coupled systems in a confined space.First, the study derivative analytical stability and synchronization conditions for the asymmetrically coupled system in an unconfined space, which are then validated through numerical simulations. Simulation results show that asymmetric coupling has a significant impact on synchronization conditions. Moreover, it is observed that irrespective of whether the system is confined, an increase in coupling asymmetry leads to a hastened synchronization pace. Additionally, the study examines the effects of boundaries on the system's collective behaviors via numerical experiments. The presence of boundaries ensures the system's stability and synchronization, and reducing these boundaries can expedite the synchronization process and amplify its effects. Finally, the study reveals that the system's output amplitude exhibits stochastic resonance as the confined boundary size increases.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11672233, 11672231)the NPU Foundation for Fundamental Research (Grant No. 3102017AX008)+1 种基金the Seed Foundation of Innovation and Creation for Graduate Student in Northwestern Polytechnical University (Grant No. ZZ2018173)the Qian Xuesen Laboratory of Space Technology Seed Fund (Grant No. QXS-ZZJJ-02)
文摘The brain neural system is often disturbed by electromagnetic and noise environments, and research on dynamic response of its interaction has received extensive attention. This paper investigates electrical activity of Morris-Lecar neural systems exposed to sinusoidal induced electric field(IEF) with random phase generated by electromagnetic effect. By introducing a membrane depolarization model under the effect of random IEF, transition state of firing patterns, including mixed-mode oscillations(MMOs) with layered inter-spike intervals(ISI) and intermittency with a power law distribution in probability density function of ISI, is obtained in a single neuron. Considering the synergistic effects of frequency and noise, coherence resonance is performed by phase noise of IEF under certain parameter conditions. For the neural network without any internal coupling, we demonstrate that synchronous oscillations can be induced by IEF coupling, and suppression of synchronous spiking is achieved effectively by phase noise of IEF. Results of the study enrich the dynamical response to electromagnetic induction and provide insights into mechanisms of noise affecting information coding and transmission in neural systems.
基金Supported by The fund of Medical and Health Research Projects of Health Commission of Zhejiang Province,No.2019KY035.
文摘BACKGROUND Synchronous liver metastasis(SLM)is an indicator of poor prognosis for colorectal cancer(CRC).Nearly 50%of CRC patients develop hepatic metastasis,with 15%-25%of them presenting with SLM.The evaluation of SLM in CRC is crucial for precise and personalized treatment.It is beneficial to detect its response to chemotherapy and choose an optimal treatment method.AIM To construct prediction models based on magnetic resonance imaging(MRI)-radiomics and clinical parameters to evaluate the chemotherapy response in SLM of CRC.METHODS A total of 102 CRC patients with 223 SLM lesions were identified and divided into disease response(DR)and disease non-response(non-DR)to chemotherapy.After standardizing the MRI images,the volume of interest was delineated and radiomics features were calculated.The MRI-radiomics logistic model was constructed after methods of variance/Mann-Whitney U test,correlation analysis,and least absolute shrinkage and selection operator in feature selecting.The radiomics score was calculated.The receiver operating characteristics curves by the DeLong test were analyzed with MedCalc software to compare the validity of all models.Additionally,the area under curves(AUCs)of DWI,T2WI,and portal phase of contrast-enhanced sequences radiomics model(Ra-DWI,Ra-T2WI,and Ra-portal phase of contrast-enhanced sequences)were calculated.The radiomicsclinical nomogram was generated by combining radiomics features and clinical characteristics of CA19-9 and clinical N staging.RESULTS The AUCs of the MRI-radiomics model were 0.733 and 0.753 for the training(156 lesions with 68 non-DR and 88 DR)and the validation(67 lesions with 29 non-DR and 38 DR)set,respectively.Additionally,the AUCs of the training and the validation set of Ra-DWI were higher than those of Ra-T2WI and Ra-portal phase of contrast-enhanced sequences(training set:0.652 vs 0.628 and 0.633,validation set:0.661 vs 0.575 and 0.543).After chemotherapy,the top four of twelve deltaradiomics features of Ra-DWI in the DR group belonged to gray-level run
文摘The effect of diversity on dynamics of coupled FitzHugh-Nagumo neurons on complex networks is numerically investigated, where each neuron is subjected to an external subthreshold signal. With the diversity the network is a mixture of excitable and oscillatory neurons, and the diversity is determined by the variance of the system＇s parameter. The complex network is constructed by randomly adding long-range connections （shortcuts） on a nearest-neighbouring coupled one-dimensional chain. Numerical results show that external signals are maximally magnified at an intermediate value of the diversity, as in the case of well-known stochastic resonance, burthermore, the effects of the number of shortcuts and coupled strength on the diversity-induced phenomena are also discussed. These findings exhibit that the diversity may play a constructive role in response to external signal, and highlight the importance of the diversity on such complex networks.
