By applying switch-signal theory, the interaction between MOS transmission switch-ing transistor and current signal in current-mode CMOS circuits is analyzed, and the theory oftransmission current-switches which is su...By applying switch-signal theory, the interaction between MOS transmission switch-ing transistor and current signal in current-mode CMOS circuits is analyzed, and the theory oftransmission current-switches which is suitable to current-mode CMOS circuits is proposed. Thecircuits, such as ternary full-adder etc., designed by using this theory have simpler circuit struc-tures and correct logic functions. It is confirmed that this theory is efficient in guiding the logicdesign of current-mode CMOS circuits at switch level.展开更多
Chronic migraine(CM)is a prevalent and highly debilitating neurological disorder.Functional magnetic resonance imaging(fMRI)studies have demonstrated associations between abnormal brain region activation and CM,yet th...Chronic migraine(CM)is a prevalent and highly debilitating neurological disorder.Functional magnetic resonance imaging(fMRI)studies have demonstrated associations between abnormal brain region activation and CM,yet the underlying complex neural circuitry mechanisms remain unclear.The spinal trigeminal nucleus caudalis(Sp5C)serves as the primary central hub for orofacial nociceptive input,receiving trigeminal pain signals and projecting to higher-order centers such as the thalamus.Therefore,we sought to investigate whether the Sp5C region and its associated circuits were involved in CM pathogenesis.In this study,we established a CM mouse model through repeated intraperitoneal injections of nitroglycerin(NTG).Using a combination of in vivo fiber photometry and in vitro c-Fos immunohistochemistry,we found a marked periorbital and plantar mechanical allodynia in CM mice,accompanied by increased glutamatergic neuronal activity in Sp5C.Chemogenetic manipulation of Sp5C glutamatergic neurons(Sp5CV^(glut2))bidirectionally modulated migraine-like behaviors and induced pain-related affective states,as evidenced by conditioned place preference/aversion(CPP/CPA)paradigms.Anterograde viral tracing revealed dense projections from Sp5C^(Vglut2)to the subthalamic nucleus(STN),which was activated in CM mice.Optogenetic activation of the Sp5C-STN pathway similarly produced migraine-like behaviors and pain-related aversive memory in mice.Altogether,we revealed a critical role of the Sp5CVglut2-STN circuit in the development and modulation of CM.Our findings provide novel mechanistic insights into the central mechanisms underlying CM,establishing potential theoretical foundations for clinical diagnosis and therapeutic development.展开更多
By applying switch-signal theory, the theory of transmission current-switches based on symmetric ternary logic is proposed, this theory is suitable to design symmetric ternary current-mode CMOS circuits. The symmetric...By applying switch-signal theory, the theory of transmission current-switches based on symmetric ternary logic is proposed, this theory is suitable to design symmetric ternary current-mode CMOS circuits. The symmetric ternary current-mode CMOS circuits designed by using this theory not only have simpler circuit structures and correct logic functions, but also can process bidirectional signals.展开更多
This paper proposes a simplification method for realization of current-mode multivalued CMOS circuits. The key of this method is to find a cover on the K-map for a given multivalued function, which fits to the realiza...This paper proposes a simplification method for realization of current-mode multivalued CMOS circuits. The key of this method is to find a cover on the K-map for a given multivalued function, which fits to the realization of current-mode CMOS circuits. The design example shows that the design presented in this paper is better than the design proposed by G. W. Dueck et al. (1987).展开更多
After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the tim...After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the timing of interventions,combined with the limitations of current methods.To address these challenges,various techniques have been developed to aid in the repair and reconstruction of neural circuits at different stages of injury.Notably,neuromodulation has garnered considerable attention for its potential to enhance nerve regeneration,provide neuroprotection,restore neurons,and regulate the neural reorganization of circuits within the cerebral cortex and corticospinal tract.To improve the effectiveness of these interventions,the implementation of multitarget early interventional neuromodulation strategies,such as electrical and magnetic stimulation,is recommended to enhance functional recovery across different phases of nerve injury.This review concisely outlines the challenges encountered following spinal cord injury,synthesizes existing neurostimulation techniques while emphasizing neuroprotection,repair,and regeneration of impaired connections,and advocates for multi-targeted,task-oriented,and timely interventions.展开更多
Replicating the chaotic characteristics inherent in nonlinear dynamical systems via machine learning(ML)is a key challenge in this rapidly advancing interdisciplinary field.In this work,we explore the potential of var...Replicating the chaotic characteristics inherent in nonlinear dynamical systems via machine learning(ML)is a key challenge in this rapidly advancing interdisciplinary field.In this work,we explore the potential of variational quantum circuits(VQC)for learning the stochastic properties of classical nonlinear dynamical systems.Specifically,we focus on the one-and two-dimensional logistic maps,which,while simple,remain under-explored in the context of learning dynamical characteristics.Our findings reveal that,even for such simple dynamical systems,accurately replicating longterm characteristics is hindered by a pronounced sensitivity to overfitting.While increasing the parameter complexity of the ML model typically enhances short-term prediction accuracy,it also leads to a degradation in the model’s ability to replicate long-term characteristics,primarily due to the detrimental effects of overfitting on generalization power.By comparing the VQC with two widely recognized classical ML techniques,which are long short-term memory(LSTM)networks for timeseries processing and reservoir computing,we demonstrate that VQC outperforms these methods in terms of replicating long-term characteristics.Our results suggest that for the ML of dynamics,it is demanded to develop more compact and efficient models(such as VQC)rather than more complicated and large-scale ones.展开更多
This paper presents a novel current-mode biquadratic circuit employing only plus type DVCCs(differential voltage current conveyors).The circuit enables LP(low-pass),BP(band-pass),HP(high-pass),BS(band-stop)and AP(all-...This paper presents a novel current-mode biquadratic circuit employing only plus type DVCCs(differential voltage current conveyors).The circuit enables LP(low-pass),BP(band-pass),HP(high-pass),BS(band-stop)and AP(all-pass)responses by the selection and addition of the input and output currents without any component matching constraints.Moreover the circuit parametersω0 and Q can be set orthogonally adjusting the circuit components.A design example is given together with simulation results by PSPICE.展开更多
Epilepsy,a common neurological disorder,is characterized by recurrent seizures that can lead to cognitive,psychological,and neurobiological consequences.The pathogenesis of epilepsy involves neuronal dysfunction at th...Epilepsy,a common neurological disorder,is characterized by recurrent seizures that can lead to cognitive,psychological,and neurobiological consequences.The pathogenesis of epilepsy involves neuronal dysfunction at the molecular,cellular,and neural circuit levels.Abnormal molecular signaling pathways or dysfunction of specific cell types can lead to epilepsy by disrupting the normal functioning of neural circuits.The continuous emergence of new technologies and the rapid advancement of existing ones have facilitated the discovery and comprehensive understanding of the neural circuit mechanisms underlying epilepsy.Therefore,this review aims to investigate the current understanding of the neural circuit mechanisms in epilepsy based on various technologies,including electroencephalography,magnetic resonance imaging,optogenetics,chemogenetics,deep brain stimulation,and brain-computer interfaces.Additionally,this review discusses these mechanisms from three perspectives:structural,synaptic,and transmitter circuits.The findings reveal that the neural circuit mechanisms of epilepsy encompass information transmission among different structures,interactions within the same structure,and the maintenance of homeostasis at the cellular,synaptic,and neurotransmitter levels.These findings offer new insights for investigating the pathophysiological mechanisms of epilepsy and enhancing its clinical diagnosis and treatment.展开更多
Exogenous neural stem cell transplantation has become one of the most promising treatment methods for chronic stroke.Recent studies have shown that most ischemia-reperfusion model rats recover spontaneously after inju...Exogenous neural stem cell transplantation has become one of the most promising treatment methods for chronic stroke.Recent studies have shown that most ischemia-reperfusion model rats recover spontaneously after injury,which limits the ability to observe long-term behavioral recovery.Here,we used a severe stroke rat model with 150 minutes of ischemia,which produced severe behavioral deficiencies that persisted at 12 weeks,to study the therapeutic effect of neural stem cells on neural restoration in chronic stroke.Our study showed that stroke model rats treated with human neural stem cells had long-term sustained recovery of motor function,reduced infarction volume,long-term human neural stem cell survival,and improved local inflammatory environment and angiogenesis.We also demonstrated that transplanted human neural stem cells differentiated into mature neurons in vivo,formed stable functional synaptic connections with host neurons,and exhibited the electrophysiological properties of functional mature neurons,indicating that they replaced the damaged host neurons.The findings showed that human fetal-derived neural stem cells had long-term effects for neurological recovery in a model of severe stroke,which suggests that human neural stem cells-based therapy may be effective for repairing damaged neural circuits in stroke patients.展开更多
In this work, an original Sallen-Key second-order low-pass filter is first turned into a current-mode one by means of the adjoint network theorem. Two nodal admittance matrices(NAM) of the filter are then educed. Furt...In this work, an original Sallen-Key second-order low-pass filter is first turned into a current-mode one by means of the adjoint network theorem. Two nodal admittance matrices(NAM) of the filter are then educed. Furthermore, these two matrices are expanded through NAM expansion approach, generating one current-mode Sallen-Key filter, which uses two compact voltage differential trans-conductance amplifiers(VDTAs) and two grounded capacitors, implements not only one low-pass transfer function but two band-pass transfer functions, and provides the non-interrelated control between the natural frequency and quality factor. As an example of the synthesized filter, a second-order VDTA filter with fo=1 MHz, Q=1, HLP=-HBP1=HBP2=1 is designed. The used synthesis approach has been confirmed with the help of circuit and computer analysis.展开更多
A current-mode DC-DC buck converter with high stability is presented. The loop gain＇s expression of the current-mode converter is derived by employing an advanced model of a current-mode control converter. After anal...A current-mode DC-DC buck converter with high stability is presented. The loop gain＇s expression of the current-mode converter is derived by employing an advanced model of a current-mode control converter. After analyzing the loop gain＇s expression, which illustrates the method of selecting suitable frequency compensation for the control loop,a novel pole-zero tracking frequency compensation is proposed. Based on theoretical analysis, a DC-DC buck converter with high stability is designed with 0.5μm-CMOS technology. The simulated results reveal that the stability of the converter is independent of the load current and the input voltage. Moreover,the converter provides a full load transient response setting time of less than 5μs and overshoots and undershoots of less than 30mV.展开更多
A state variable method of converting single-resistance-controlled- oscillators (SRCO), into universal current-mode biquad (offering realizations of all the five standard filter functions namely, low pass, band pass, ...A state variable method of converting single-resistance-controlled- oscillators (SRCO), into universal current-mode biquad (offering realizations of all the five standard filter functions namely, low pass, band pass, high pass, notch and all pass) has been highlighted. The workability of the exemplary implementation of the derived current-mode universal biquad has been demonstrated by PSPICE simulation results based upon 0.35 μ m technology. It is expected that the proposed method can be applied to other SRCOs to generate other multifunction filter structures.展开更多
An electronically controllable fully uncoupled explicit current-mode quadrature oscillator employing Voltage Differencing Transconductance Amplifiers (VDTAs) as active elements has been presented. The proposed configu...An electronically controllable fully uncoupled explicit current-mode quadrature oscillator employing Voltage Differencing Transconductance Amplifiers (VDTAs) as active elements has been presented. The proposed configuration employs two VDTAs along with grounded capacitors and offers the following advantageous features 1) fully and electronically independent control of condition of oscillation (CO) and frequency of oscillation (FO);2) explicit current-mode quadrature oscillations;and 3) low active and passive sensitivities. The workability of proposed configuration has been demonstrated by PSPICE simulations with TSMC CMOS 0.18 μm process parameters.展开更多
This paper presents a synthesis of current-mode PI, PD and PID controllers employing current controlled current differential buffer amplifiers (CCCDBAs). The features of these controllers are that: the output paramete...This paper presents a synthesis of current-mode PI, PD and PID controllers employing current controlled current differential buffer amplifiers (CCCDBAs). The features of these controllers are that: the output parameters can be electronically/independently controlled by adjusting corresponding bias currents in the proportional, integral, and deviation controllers;circuit description of the PID controller is simply formulated, it consists of four CCCDBAs cooperating with two grounded capacitors, and PI and PD controllers are composed of three CCCCDBAs and a grounded capacitor. Without any external resistor, the proposed circuits are very suitable to develop into integrated circuit architecture. The given results from the PSpice simulation agree well with the theoretical anticipation. The approximate power consumption in a closed loop control system consisting of the PI, PD and PID controller with low-pass filter passive plant are 4.03 mW, 4.85 mW and 5.71 mW, respectively, at ±1.5 V power supply voltages.展开更多
A versatile current-mode biquadratic filter using three operational amplifiers and nine passive elements is proposed. By suitably choosing the output branch, lowpass, bandpass, highpass, bandstop and allpass transfer ...A versatile current-mode biquadratic filter using three operational amplifiers and nine passive elements is proposed. By suitably choosing the output branch, lowpass, bandpass, highpass, bandstop and allpass transfer functions are realized simultaneously without changing the circuit configuration and elements. Two circuits, one is for low frequency application and the other for high frequency, are proposed. The center frequency, quality factor and gain constants of the circuit can be tuned independently. Simulated results show that the circuits work successfully.展开更多
This article presents an active-only current-mode universal biquad filter performing three standard functions: low-pass, high-pass and band-pass function, which can be readily modified to achieve the rest functions (b...This article presents an active-only current-mode universal biquad filter performing three standard functions: low-pass, high-pass and band-pass function, which can be readily modified to achieve the rest functions (band-stop and all-pass). The circuit principle is based on active-only circuit designed by using differentiators which are constructed from current controlled current conveyor transconductance amplifier (CCCCTA) cooperating with an internally frequency compensated operational amplifier (OA). The features of the circuit are that: the pole frequency and quality factor can be independently tuned via the input bias currents and it is ideally temperature-insensitive, its circuit description is very simple, consisting of 3 CCCCTAs and 2 operational amplifiers, and the proposed circuit is very appropriate for further developing into integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation.展开更多
This paper presents a universal current-controlled current-mode biquad filter employing current controlled current conveyor trans-conductance amplifiers (CCCCTAs). The proposed filter employs only three MO- CCCCTAs an...This paper presents a universal current-controlled current-mode biquad filter employing current controlled current conveyor trans-conductance amplifiers (CCCCTAs). The proposed filter employs only three MO- CCCCTAs and two grounded capacitors. The proposed filter can simultaneously realize low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) responses in current form by choosing appropriate current output branches. In addition, the pole frequency and quality factor of the proposed filter circuit can be tuned independently and electronically over the wide range by adjusting the external bias currents. The circuit possesses low active and passive sensitivity performance. The validity of proposed filter is verified through PSPICE simulations.展开更多
One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltag...One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions;low active and passive sensitivities;employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.展开更多
Five new electronically-controllable second order current-mode sinusoidal oscillators using three mul-ti-output operational transconductance amplifiers (MO-OTAs) and two grounded capacitors (GC) have been presented. S...Five new electronically-controllable second order current-mode sinusoidal oscillators using three mul-ti-output operational transconductance amplifiers (MO-OTAs) and two grounded capacitors (GC) have been presented. Simulation results are included to confirm the theoretical analysis based upon CMOS OTAs implementable in 0.5 μm technology.展开更多
A new universal multiple input multiple output (MIMO) type current-mode biquad employing two dual output current conveyors (DOCCII), one multiple output current controlled current amplifier (MOCCCA) and four passive g...A new universal multiple input multiple output (MIMO) type current-mode biquad employing two dual output current conveyors (DOCCII), one multiple output current controlled current amplifier (MOCCCA) and four passive grounded elements is proposed which can realize all the five basic filtering functions namely, low-pass (LP), high-pass (HP), band-pass (BP), band-stop (BR) and all-pass (AP) in current mode from the same configuration. The centre frequency can be set by the passive elements of the circuit and the quality factor Q0 is electronically tunable through bias currents of the MOCCCA. Therefore, the biquad filter has independent tenability for the and Q0. The active and passive sensitivities of Q0 and are low. The workability of the new configuration has been demonstrated by PSPICE simulation results based upon a CMOS CCII in0.35μm technology.展开更多
基金Supported by National Natural Science Foundation of China
文摘By applying switch-signal theory, the interaction between MOS transmission switch-ing transistor and current signal in current-mode CMOS circuits is analyzed, and the theory oftransmission current-switches which is suitable to current-mode CMOS circuits is proposed. Thecircuits, such as ternary full-adder etc., designed by using this theory have simpler circuit struc-tures and correct logic functions. It is confirmed that this theory is efficient in guiding the logicdesign of current-mode CMOS circuits at switch level.
基金supported by the National Natural Science Foundation of China(No.32571336 and 32271048)Research Funds of Centre for Leading Medicine and Advanced Technologies of IHM(No.2025IHM01100)。
文摘Chronic migraine(CM)is a prevalent and highly debilitating neurological disorder.Functional magnetic resonance imaging(fMRI)studies have demonstrated associations between abnormal brain region activation and CM,yet the underlying complex neural circuitry mechanisms remain unclear.The spinal trigeminal nucleus caudalis(Sp5C)serves as the primary central hub for orofacial nociceptive input,receiving trigeminal pain signals and projecting to higher-order centers such as the thalamus.Therefore,we sought to investigate whether the Sp5C region and its associated circuits were involved in CM pathogenesis.In this study,we established a CM mouse model through repeated intraperitoneal injections of nitroglycerin(NTG).Using a combination of in vivo fiber photometry and in vitro c-Fos immunohistochemistry,we found a marked periorbital and plantar mechanical allodynia in CM mice,accompanied by increased glutamatergic neuronal activity in Sp5C.Chemogenetic manipulation of Sp5C glutamatergic neurons(Sp5CV^(glut2))bidirectionally modulated migraine-like behaviors and induced pain-related affective states,as evidenced by conditioned place preference/aversion(CPP/CPA)paradigms.Anterograde viral tracing revealed dense projections from Sp5C^(Vglut2)to the subthalamic nucleus(STN),which was activated in CM mice.Optogenetic activation of the Sp5C-STN pathway similarly produced migraine-like behaviors and pain-related aversive memory in mice.Altogether,we revealed a critical role of the Sp5CVglut2-STN circuit in the development and modulation of CM.Our findings provide novel mechanistic insights into the central mechanisms underlying CM,establishing potential theoretical foundations for clinical diagnosis and therapeutic development.
基金National Natural Science Foundation of ChinaNatural science Foundation of Zhejiang Province
文摘By applying switch-signal theory, the theory of transmission current-switches based on symmetric ternary logic is proposed, this theory is suitable to design symmetric ternary current-mode CMOS circuits. The symmetric ternary current-mode CMOS circuits designed by using this theory not only have simpler circuit structures and correct logic functions, but also can process bidirectional signals.
基金Supported by the National Natural Science Foundation of China
文摘This paper proposes a simplification method for realization of current-mode multivalued CMOS circuits. The key of this method is to find a cover on the K-map for a given multivalued function, which fits to the realization of current-mode CMOS circuits. The design example shows that the design presented in this paper is better than the design proposed by G. W. Dueck et al. (1987).
基金supported by the National Key Research and Development Program of China,No.2023YFC3603705(to DX)the National Natural Science Foundation of China,No.82302866(to YZ).
文摘After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the timing of interventions,combined with the limitations of current methods.To address these challenges,various techniques have been developed to aid in the repair and reconstruction of neural circuits at different stages of injury.Notably,neuromodulation has garnered considerable attention for its potential to enhance nerve regeneration,provide neuroprotection,restore neurons,and regulate the neural reorganization of circuits within the cerebral cortex and corticospinal tract.To improve the effectiveness of these interventions,the implementation of multitarget early interventional neuromodulation strategies,such as electrical and magnetic stimulation,is recommended to enhance functional recovery across different phases of nerve injury.This review concisely outlines the challenges encountered following spinal cord injury,synthesizes existing neurostimulation techniques while emphasizing neuroprotection,repair,and regeneration of impaired connections,and advocates for multi-targeted,task-oriented,and timely interventions.
基金Project supported in part by Beijing Natural Science Foundation(Grant No.1232025)Peng Huanwu Visiting Pro-fessor Program,and Academy for Multidisciplinary Studies,Capital Normal University.
文摘Replicating the chaotic characteristics inherent in nonlinear dynamical systems via machine learning(ML)is a key challenge in this rapidly advancing interdisciplinary field.In this work,we explore the potential of variational quantum circuits(VQC)for learning the stochastic properties of classical nonlinear dynamical systems.Specifically,we focus on the one-and two-dimensional logistic maps,which,while simple,remain under-explored in the context of learning dynamical characteristics.Our findings reveal that,even for such simple dynamical systems,accurately replicating longterm characteristics is hindered by a pronounced sensitivity to overfitting.While increasing the parameter complexity of the ML model typically enhances short-term prediction accuracy,it also leads to a degradation in the model’s ability to replicate long-term characteristics,primarily due to the detrimental effects of overfitting on generalization power.By comparing the VQC with two widely recognized classical ML techniques,which are long short-term memory(LSTM)networks for timeseries processing and reservoir computing,we demonstrate that VQC outperforms these methods in terms of replicating long-term characteristics.Our results suggest that for the ML of dynamics,it is demanded to develop more compact and efficient models(such as VQC)rather than more complicated and large-scale ones.
文摘This paper presents a novel current-mode biquadratic circuit employing only plus type DVCCs(differential voltage current conveyors).The circuit enables LP(low-pass),BP(band-pass),HP(high-pass),BS(band-stop)and AP(all-pass)responses by the selection and addition of the input and output currents without any component matching constraints.Moreover the circuit parametersω0 and Q can be set orthogonally adjusting the circuit components.A design example is given together with simulation results by PSPICE.
基金supported by Basic Research Programs of Science and Technology Commission Foundation of Shanxi Province,No.20210302123486(to WJ).
文摘Epilepsy,a common neurological disorder,is characterized by recurrent seizures that can lead to cognitive,psychological,and neurobiological consequences.The pathogenesis of epilepsy involves neuronal dysfunction at the molecular,cellular,and neural circuit levels.Abnormal molecular signaling pathways or dysfunction of specific cell types can lead to epilepsy by disrupting the normal functioning of neural circuits.The continuous emergence of new technologies and the rapid advancement of existing ones have facilitated the discovery and comprehensive understanding of the neural circuit mechanisms underlying epilepsy.Therefore,this review aims to investigate the current understanding of the neural circuit mechanisms in epilepsy based on various technologies,including electroencephalography,magnetic resonance imaging,optogenetics,chemogenetics,deep brain stimulation,and brain-computer interfaces.Additionally,this review discusses these mechanisms from three perspectives:structural,synaptic,and transmitter circuits.The findings reveal that the neural circuit mechanisms of epilepsy encompass information transmission among different structures,interactions within the same structure,and the maintenance of homeostasis at the cellular,synaptic,and neurotransmitter levels.These findings offer new insights for investigating the pathophysiological mechanisms of epilepsy and enhancing its clinical diagnosis and treatment.
文摘Exogenous neural stem cell transplantation has become one of the most promising treatment methods for chronic stroke.Recent studies have shown that most ischemia-reperfusion model rats recover spontaneously after injury,which limits the ability to observe long-term behavioral recovery.Here,we used a severe stroke rat model with 150 minutes of ischemia,which produced severe behavioral deficiencies that persisted at 12 weeks,to study the therapeutic effect of neural stem cells on neural restoration in chronic stroke.Our study showed that stroke model rats treated with human neural stem cells had long-term sustained recovery of motor function,reduced infarction volume,long-term human neural stem cell survival,and improved local inflammatory environment and angiogenesis.We also demonstrated that transplanted human neural stem cells differentiated into mature neurons in vivo,formed stable functional synaptic connections with host neurons,and exhibited the electrophysiological properties of functional mature neurons,indicating that they replaced the damaged host neurons.The findings showed that human fetal-derived neural stem cells had long-term effects for neurological recovery in a model of severe stroke,which suggests that human neural stem cells-based therapy may be effective for repairing damaged neural circuits in stroke patients.
基金the Natural Science Foundation of Shaanxi Province (2017JM6087)。
文摘In this work, an original Sallen-Key second-order low-pass filter is first turned into a current-mode one by means of the adjoint network theorem. Two nodal admittance matrices(NAM) of the filter are then educed. Furthermore, these two matrices are expanded through NAM expansion approach, generating one current-mode Sallen-Key filter, which uses two compact voltage differential trans-conductance amplifiers(VDTAs) and two grounded capacitors, implements not only one low-pass transfer function but two band-pass transfer functions, and provides the non-interrelated control between the natural frequency and quality factor. As an example of the synthesized filter, a second-order VDTA filter with fo=1 MHz, Q=1, HLP=-HBP1=HBP2=1 is designed. The used synthesis approach has been confirmed with the help of circuit and computer analysis.
文摘A current-mode DC-DC buck converter with high stability is presented. The loop gain＇s expression of the current-mode converter is derived by employing an advanced model of a current-mode control converter. After analyzing the loop gain＇s expression, which illustrates the method of selecting suitable frequency compensation for the control loop,a novel pole-zero tracking frequency compensation is proposed. Based on theoretical analysis, a DC-DC buck converter with high stability is designed with 0.5μm-CMOS technology. The simulated results reveal that the stability of the converter is independent of the load current and the input voltage. Moreover,the converter provides a full load transient response setting time of less than 5μs and overshoots and undershoots of less than 30mV.
文摘A state variable method of converting single-resistance-controlled- oscillators (SRCO), into universal current-mode biquad (offering realizations of all the five standard filter functions namely, low pass, band pass, high pass, notch and all pass) has been highlighted. The workability of the exemplary implementation of the derived current-mode universal biquad has been demonstrated by PSPICE simulation results based upon 0.35 μ m technology. It is expected that the proposed method can be applied to other SRCOs to generate other multifunction filter structures.
文摘An electronically controllable fully uncoupled explicit current-mode quadrature oscillator employing Voltage Differencing Transconductance Amplifiers (VDTAs) as active elements has been presented. The proposed configuration employs two VDTAs along with grounded capacitors and offers the following advantageous features 1) fully and electronically independent control of condition of oscillation (CO) and frequency of oscillation (FO);2) explicit current-mode quadrature oscillations;and 3) low active and passive sensitivities. The workability of proposed configuration has been demonstrated by PSPICE simulations with TSMC CMOS 0.18 μm process parameters.
文摘This paper presents a synthesis of current-mode PI, PD and PID controllers employing current controlled current differential buffer amplifiers (CCCDBAs). The features of these controllers are that: the output parameters can be electronically/independently controlled by adjusting corresponding bias currents in the proportional, integral, and deviation controllers;circuit description of the PID controller is simply formulated, it consists of four CCCDBAs cooperating with two grounded capacitors, and PI and PD controllers are composed of three CCCCDBAs and a grounded capacitor. Without any external resistor, the proposed circuits are very suitable to develop into integrated circuit architecture. The given results from the PSpice simulation agree well with the theoretical anticipation. The approximate power consumption in a closed loop control system consisting of the PI, PD and PID controller with low-pass filter passive plant are 4.03 mW, 4.85 mW and 5.71 mW, respectively, at ±1.5 V power supply voltages.
文摘A versatile current-mode biquadratic filter using three operational amplifiers and nine passive elements is proposed. By suitably choosing the output branch, lowpass, bandpass, highpass, bandstop and allpass transfer functions are realized simultaneously without changing the circuit configuration and elements. Two circuits, one is for low frequency application and the other for high frequency, are proposed. The center frequency, quality factor and gain constants of the circuit can be tuned independently. Simulated results show that the circuits work successfully.
文摘This article presents an active-only current-mode universal biquad filter performing three standard functions: low-pass, high-pass and band-pass function, which can be readily modified to achieve the rest functions (band-stop and all-pass). The circuit principle is based on active-only circuit designed by using differentiators which are constructed from current controlled current conveyor transconductance amplifier (CCCCTA) cooperating with an internally frequency compensated operational amplifier (OA). The features of the circuit are that: the pole frequency and quality factor can be independently tuned via the input bias currents and it is ideally temperature-insensitive, its circuit description is very simple, consisting of 3 CCCCTAs and 2 operational amplifiers, and the proposed circuit is very appropriate for further developing into integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation.
文摘This paper presents a universal current-controlled current-mode biquad filter employing current controlled current conveyor trans-conductance amplifiers (CCCCTAs). The proposed filter employs only three MO- CCCCTAs and two grounded capacitors. The proposed filter can simultaneously realize low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) responses in current form by choosing appropriate current output branches. In addition, the pole frequency and quality factor of the proposed filter circuit can be tuned independently and electronically over the wide range by adjusting the external bias currents. The circuit possesses low active and passive sensitivity performance. The validity of proposed filter is verified through PSPICE simulations.
文摘One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions;low active and passive sensitivities;employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.
文摘Five new electronically-controllable second order current-mode sinusoidal oscillators using three mul-ti-output operational transconductance amplifiers (MO-OTAs) and two grounded capacitors (GC) have been presented. Simulation results are included to confirm the theoretical analysis based upon CMOS OTAs implementable in 0.5 μm technology.
文摘A new universal multiple input multiple output (MIMO) type current-mode biquad employing two dual output current conveyors (DOCCII), one multiple output current controlled current amplifier (MOCCCA) and four passive grounded elements is proposed which can realize all the five basic filtering functions namely, low-pass (LP), high-pass (HP), band-pass (BP), band-stop (BR) and all-pass (AP) in current mode from the same configuration. The centre frequency can be set by the passive elements of the circuit and the quality factor Q0 is electronically tunable through bias currents of the MOCCCA. Therefore, the biquad filter has independent tenability for the and Q0. The active and passive sensitivities of Q0 and are low. The workability of the new configuration has been demonstrated by PSPICE simulation results based upon a CMOS CCII in0.35μm technology.
