Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Cu...Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.展开更多
The general contact problem of a disc squeezed between jaws of arbitrary curvature is considered employing Muskhelishvili’s complex potentials.Taking advantage of the general solution introduced,the closed-form expre...The general contact problem of a disc squeezed between jaws of arbitrary curvature is considered employing Muskhelishvili’s complex potentials.Taking advantage of the general solution introduced,the closed-form expressions for the stresses along strategic loci(loaded rim,loaded diameter,disc’s center)are obtained,in terms of the ratio r of the disc’s to the jaw’s curvature.Then,the effect of r(as well as that of the relative stiffness of the disc’s and jaw’s materials dictating the contact arc)on the stress distribution along these loci is explored.It is concluded that,for both smooth contact(zero friction)and contact with friction,the role of the jaw’s curvature is significant not only along the disc-jaw contact arc(as it could be expected),but also all along the loaded diameter.On the other hand,it is indicated that the stress field at the disc’s center is more or less insensitive to the jaw’s curvature assuming that r lies within the range(0,0.67)or in other words within the limits defined by the two standardized suggestions,i.e.that of American Society for Testing and Materials(ASTM)(plane loading platens with r ? 0)and that of International Society for Rock Mechanics(ISRM)(curved jaws with r ? 0.67).The upper limit of this range is a kind of compromise between the need to make the stress field at the disc’s center independent of the boundary conditions while keeping at the same time the contact angle large enough to reduce the stress concentration and the risk for premature fracture initiation far from the disc’s center.For jaws with radius of curvature exceeded by that suggested by ISRM,the stress field at the disc’s center is significantly influenced.Especially for jaws with radius approaching that of the disc,the stress field at the disc’s center is dramatically distorted rendering Hondros’ formula inapplicable and the test results erroneous.展开更多
To find possible therapeutic applications involving the Central Nervous System (CNS) for herbals is a major challenge during functional food and drug discovery and development programmes. Despite the availability of n...To find possible therapeutic applications involving the Central Nervous System (CNS) for herbals is a major challenge during functional food and drug discovery and development programmes. Despite the availability of numerous in vitro and in vivo tests, there is no single agreed screening procedure for pharmacological testing of herbal extracts with anticipated CNS activity. Experience gained from more than 25 years of testing has shown that two models give reasonably reliable orientation for future CNS applications: construction of an electropharmacogram based on wireless recording of field potentials from the depth of the brain of freely moving rats (Tele-Stereo-EEG) and recording of the population spike produced by pyramidal cells from hippocampal slices in vitro. A combination of these two methods has now been used to characterize the pharmacological profile of extracts from Rhodiola rosea root, Oenothera paradoxa seeds and Paullinia cupana seeds. Spectral analysis of field potentials revealed attenuation of alpha2 and beta1 waves was common for all extracts. According to previous studies, this is interpreted as activation of the dopaminergic and glutamatergic transmission. In addition, Oenothera and Rhodiola extracts attenuated delta and theta power, probably related to interference with the cholinergic and norepinephrinergic transmission, respectively. Using discriminant analysis for comparison with reference pharmaceutical and botanical drugs, Rhodiola projected near the position of Ginkgo extract, whereas Oenothera extract was projected near the position of Tramadol, an analgesic drug. Physical motion was increased only in the presence of Paullinia extract and caffeine. Increases of long-term potentiation were observed in the presence of Rhodiola extract, Paullinia extract and caffeine. The combined information predicts stimulant and cognitive function-enhancing activities in humans for the Rhodiola extract, which could also be used as a possible caffeine-replacement, and antidepressant and analgesic activ展开更多
This review hopes to clearly explain the following viewpoints： （1） Neuronal synchronization underlies brain functioning, and it seems possible that blocking excessive synchronization in an epileptic neural network ...This review hopes to clearly explain the following viewpoints： （1） Neuronal synchronization underlies brain functioning, and it seems possible that blocking excessive synchronization in an epileptic neural network could reduce or even control seizures. （2） Local field potential coupling is a very common phenomenon during synchronization in networks. Removal of neurons or neuronal networks that are coupled can significantly alter the extracellular field potential. Interventions of coupling mediated by local field potentials could result in desynchronization of epileptic seizures. （3） The synchronized electrical activity generated by neurons is sensitive to changes in the size of the extracellular space, which affects the efficiency of field potential transmission and the threshold of cell excitability. （4） Manipulations of the field potential fluctuations could help block synchronization at seizure onset.展开更多
Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta o...Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta oscillations in implicit timing tasks are lacking. In this study, we set up an implicit motor timing task and found a modulation pattern of beta oscillations with temporal perception during movement preparation. We trained two macaques in a repetitive visually-guided reach-to-grasp task with different holding intervals. Spikes and local field potentials were recorded from microelectrode arrays in the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. We analyzed the association between beta oscillations and temporal interval in fixedduration experiments(500 ms as the Short Group and1500 ms as the Long Group) and random-duration experiments(500 ms to 1500 ms). The results showed that the peak beta frequencies in both experiments ranged from15 Hz to 25 Hz. The beta power was higher during the hold period than the movement(reach and grasp) period.Further, in the fixed-duration experiments, the mean poweras well as the maximum rate of change of beta power in the first 300 ms were higher in the Short Group than in the Long Group when aligned with the Center Hit event. In contrast, in the random-duration experiments, the corresponding values showed no statistical differences among groups. The peak latency of beta power was shorter in the Short Group than in the Long Group in the fixed-duration experiments, while no consistent modulation pattern was found in the random-duration experiments. These results indicate that beta oscillations can modulate with temporal interval in their power mode. The synchronization period of beta power could reflect the cognitive set maintaining working memory of the temporal structure and attention.展开更多
The transient response of a system of independent electrodes buried in a semi-infinite conducting medium is studied. Using a simple and versatile numerical scheme written by the authors and based on the Electric Field...The transient response of a system of independent electrodes buried in a semi-infinite conducting medium is studied. Using a simple and versatile numerical scheme written by the authors and based on the Electric Field Integral Equation (EFIE), the effect caused by harmonic signals ranging on frequency from Hz to hundred of MHz, and also by lightning type driving signal striking at a remote point far from the conductors, is extensively studied. The value of the scalar potential appearing on the electrodes as a function of the frequency of the applied signal is one of the variables investigated. Other features such as the input impedance at the injection point of the signal and the Ground Potential Rise (GPR) over the electrode system are also discussed.展开更多
In order to achieve atmospheric pressure diffuse dielectric barrier discharge(DBD) in air, a helical-helical electrode structure with a floating-voltage electrode is proposed in this paper.Results from an electric fie...In order to achieve atmospheric pressure diffuse dielectric barrier discharge(DBD) in air, a helical-helical electrode structure with a floating-voltage electrode is proposed in this paper.Results from an electric field distribution simulation indicate that strong electric fields are formed where the helical-contact electrodes’ insulating layers are in contact with each other, as well as near the floating-voltage electrode, which contributes to the production of a large number of seed electrons. The electric field within the air gap is weak(<3?×?106 V m-1), which inhibits the rapid development of electron avalanches and the formation of filament discharge. The experimental result shows that a 3.0 mm width diffuse DBD is generated in air. Moreover, based on the study of the helical-helical electrode with a floating-voltage electrode, a threedimensional electrode structure is presented, and a three-dimensional diffuse discharge is generated in air by adopting this electrode structure. The plasma studied is stable and demonstrates good diffusion characteristics, and therefore has potential applications in the field of exhaust gas treatment and air purification.展开更多
An appropriate density dependence of hyperon potentials is important for the stiffening of the equation of state and massive neutron stars. To persist in covariance and thermodynamic consistency, the rearrangement ter...An appropriate density dependence of hyperon potentials is important for the stiffening of the equation of state and massive neutron stars. To persist in covariance and thermodynamic consistency, the rearrangement term is indispensable. In this work, we derive the rearrangement term for hyperon potentials with arbitrary density- dependence. The importance of the rearrangement term is also exhibited in numerical instances.展开更多
Esfenvalerate belongs to the pyrethroid group of insecticides which display significant selective toxicity against insects compared to mammalian species, nevertheless, they may pose health risks, especially in case of...Esfenvalerate belongs to the pyrethroid group of insecticides which display significant selective toxicity against insects compared to mammalian species, nevertheless, they may pose health risks, especially in case of accidental exposure. The aim of the present study was to model the effect of acute, relatively high-dose exposure of the esfenvalerate-containing formulation Sumi-Alpha?. Eventual functional alterations in the central nervous system and in the gastrointestinal tract were studied on in vitro tissue preparations at different delays after intragastric administration to rats. Neuronal effects were characterized by field potential recording in cortical and hippocampal brain slices, while gastrointestinal effects were examined by analyzing the motility and excitability of isolated ileum segments. On the brain slices originating from esfenvalerate-treated animals, changes in excitability of both inhibitory and excitatory type could be observed. Voltage thresholds necessary to evoke responses in neocortex slices were elevated, and population spike amplitudes were lower in hippocampal slices. However, epileptiform potentials with pronounced late components were also observed. A decreased long-term potentiation (LTP) could be seen in both brain areas after esfenvalerate treatment. Seizure susceptibility of the slices was not significantly altered, but tended to be somewhat higher in slices originating from treated rats. In ileum segments, both spontaneous and acetyl-choline (ACh)-elicited contractions were modified by treatment. Esfenvalerate raised the amplitude of contractions in the low ACh concentration range. However, the solvent xylene also considerably contributed to the detected changes. We can conclude that a relatively high, single oral dose of Sumi-Alpha? exerted mild and temporary effects on the elementary brain functions and intestine functions of the rat.展开更多
This paper reports the intrinsic-structure DC characteristics computed from the analytical electrochemical current theory of the bipolar field-effect transistor （BiFET） with two identical MOS gates on nanometer-thic...This paper reports the intrinsic-structure DC characteristics computed from the analytical electrochemical current theory of the bipolar field-effect transistor （BiFET） with two identical MOS gates on nanometer-thick pure-base of silicon with no generation-recombination-trapping. Numerical solutions are rapidly obtained for the three potential variables,electrostatic and electron and hole electrochemical potentials,to give the electron and hole surface and volume channel currents,using our cross-link two-route or zig-zag one-route recursive iteration algorithms. Boundary conditions on the three potentials dominantly affect the intrinsic-structure DC characteristics,illustrated by examples covering 20-decades of current （10-22 to 10-2 A/Square at 400cm^2/（V · s） mobility for 1.5nm gate-oxide, and 30nm-thick pure-base）. Aside from the domination of carrier space-charge-limited drift current in the strong surface channels,observed in the theory is also the classical drift current saturation due to physical pinch-off of an impure-base volume channel depicted by the 1952 Shockley junction-gate field-effect transistor theory,and its extension to complete cut-off of the pure-base volume channel,due to vanishing carrier screening by the few electron and hole carriers in the pure-base,with Debye length （25mm） much larger than device dimension （25nm）.展开更多
基金supported by the National Natural Science Foundation of China,No.82071254(to WZ).
文摘Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.
基金co-financed by the EU(European Social Fund-ESF)Greek National Funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework(NSRF)-ResearchFunding Program:THALES:Reinforcement of the interdisciplinary and/or inter-institutional research and innovation
文摘The general contact problem of a disc squeezed between jaws of arbitrary curvature is considered employing Muskhelishvili’s complex potentials.Taking advantage of the general solution introduced,the closed-form expressions for the stresses along strategic loci(loaded rim,loaded diameter,disc’s center)are obtained,in terms of the ratio r of the disc’s to the jaw’s curvature.Then,the effect of r(as well as that of the relative stiffness of the disc’s and jaw’s materials dictating the contact arc)on the stress distribution along these loci is explored.It is concluded that,for both smooth contact(zero friction)and contact with friction,the role of the jaw’s curvature is significant not only along the disc-jaw contact arc(as it could be expected),but also all along the loaded diameter.On the other hand,it is indicated that the stress field at the disc’s center is more or less insensitive to the jaw’s curvature assuming that r lies within the range(0,0.67)or in other words within the limits defined by the two standardized suggestions,i.e.that of American Society for Testing and Materials(ASTM)(plane loading platens with r ? 0)and that of International Society for Rock Mechanics(ISRM)(curved jaws with r ? 0.67).The upper limit of this range is a kind of compromise between the need to make the stress field at the disc’s center independent of the boundary conditions while keeping at the same time the contact angle large enough to reduce the stress concentration and the risk for premature fracture initiation far from the disc’s center.For jaws with radius of curvature exceeded by that suggested by ISRM,the stress field at the disc’s center is significantly influenced.Especially for jaws with radius approaching that of the disc,the stress field at the disc’s center is dramatically distorted rendering Hondros’ formula inapplicable and the test results erroneous.
文摘To find possible therapeutic applications involving the Central Nervous System (CNS) for herbals is a major challenge during functional food and drug discovery and development programmes. Despite the availability of numerous in vitro and in vivo tests, there is no single agreed screening procedure for pharmacological testing of herbal extracts with anticipated CNS activity. Experience gained from more than 25 years of testing has shown that two models give reasonably reliable orientation for future CNS applications: construction of an electropharmacogram based on wireless recording of field potentials from the depth of the brain of freely moving rats (Tele-Stereo-EEG) and recording of the population spike produced by pyramidal cells from hippocampal slices in vitro. A combination of these two methods has now been used to characterize the pharmacological profile of extracts from Rhodiola rosea root, Oenothera paradoxa seeds and Paullinia cupana seeds. Spectral analysis of field potentials revealed attenuation of alpha2 and beta1 waves was common for all extracts. According to previous studies, this is interpreted as activation of the dopaminergic and glutamatergic transmission. In addition, Oenothera and Rhodiola extracts attenuated delta and theta power, probably related to interference with the cholinergic and norepinephrinergic transmission, respectively. Using discriminant analysis for comparison with reference pharmaceutical and botanical drugs, Rhodiola projected near the position of Ginkgo extract, whereas Oenothera extract was projected near the position of Tramadol, an analgesic drug. Physical motion was increased only in the presence of Paullinia extract and caffeine. Increases of long-term potentiation were observed in the presence of Rhodiola extract, Paullinia extract and caffeine. The combined information predicts stimulant and cognitive function-enhancing activities in humans for the Rhodiola extract, which could also be used as a possible caffeine-replacement, and antidepressant and analgesic activ
基金supported by grants from the National Natural Science Foundation of China,No. 30971534125 Project of the Third Xiangya Hospital of Central South University,China
文摘This review hopes to clearly explain the following viewpoints： （1） Neuronal synchronization underlies brain functioning, and it seems possible that blocking excessive synchronization in an epileptic neural network could reduce or even control seizures. （2） Local field potential coupling is a very common phenomenon during synchronization in networks. Removal of neurons or neuronal networks that are coupled can significantly alter the extracellular field potential. Interventions of coupling mediated by local field potentials could result in desynchronization of epileptic seizures. （3） The synchronized electrical activity generated by neurons is sensitive to changes in the size of the extracellular space, which affects the efficiency of field potential transmission and the threshold of cell excitability. （4） Manipulations of the field potential fluctuations could help block synchronization at seizure onset.
基金the International Cooperation and Exchange of the National Natural Science Foundation of China (31320103914)the General Program of the National Natural Science Foundation of China (31370987)+2 种基金the National Natural Science Foundation of China for Outstanding Young Scholars (81622027)the Beijing Nova Program of China (2016B615)the National Basic Research Development Program of China (2017YFA0106100)
文摘Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta oscillations in implicit timing tasks are lacking. In this study, we set up an implicit motor timing task and found a modulation pattern of beta oscillations with temporal perception during movement preparation. We trained two macaques in a repetitive visually-guided reach-to-grasp task with different holding intervals. Spikes and local field potentials were recorded from microelectrode arrays in the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. We analyzed the association between beta oscillations and temporal interval in fixedduration experiments(500 ms as the Short Group and1500 ms as the Long Group) and random-duration experiments(500 ms to 1500 ms). The results showed that the peak beta frequencies in both experiments ranged from15 Hz to 25 Hz. The beta power was higher during the hold period than the movement(reach and grasp) period.Further, in the fixed-duration experiments, the mean poweras well as the maximum rate of change of beta power in the first 300 ms were higher in the Short Group than in the Long Group when aligned with the Center Hit event. In contrast, in the random-duration experiments, the corresponding values showed no statistical differences among groups. The peak latency of beta power was shorter in the Short Group than in the Long Group in the fixed-duration experiments, while no consistent modulation pattern was found in the random-duration experiments. These results indicate that beta oscillations can modulate with temporal interval in their power mode. The synchronization period of beta power could reflect the cognitive set maintaining working memory of the temporal structure and attention.
基金supported by the Scientific and Technical Program of Fujian Province(No.FJGXY04015)the Natural Science Foundation of Fujian ProvinceChina(No.C0710022)
文摘The transient response of a system of independent electrodes buried in a semi-infinite conducting medium is studied. Using a simple and versatile numerical scheme written by the authors and based on the Electric Field Integral Equation (EFIE), the effect caused by harmonic signals ranging on frequency from Hz to hundred of MHz, and also by lightning type driving signal striking at a remote point far from the conductors, is extensively studied. The value of the scalar potential appearing on the electrodes as a function of the frequency of the applied signal is one of the variables investigated. Other features such as the input impedance at the injection point of the signal and the Ground Potential Rise (GPR) over the electrode system are also discussed.
基金supported by National Natural Science Foundation of China (No. 51577011)
文摘In order to achieve atmospheric pressure diffuse dielectric barrier discharge(DBD) in air, a helical-helical electrode structure with a floating-voltage electrode is proposed in this paper.Results from an electric field distribution simulation indicate that strong electric fields are formed where the helical-contact electrodes’ insulating layers are in contact with each other, as well as near the floating-voltage electrode, which contributes to the production of a large number of seed electrons. The electric field within the air gap is weak(<3?×?106 V m-1), which inhibits the rapid development of electron avalanches and the formation of filament discharge. The experimental result shows that a 3.0 mm width diffuse DBD is generated in air. Moreover, based on the study of the helical-helical electrode with a floating-voltage electrode, a threedimensional electrode structure is presented, and a three-dimensional diffuse discharge is generated in air by adopting this electrode structure. The plasma studied is stable and demonstrates good diffusion characteristics, and therefore has potential applications in the field of exhaust gas treatment and air purification.
基金Supported by National Natural Science Foundation of China(10975033,11275048)
文摘An appropriate density dependence of hyperon potentials is important for the stiffening of the equation of state and massive neutron stars. To persist in covariance and thermodynamic consistency, the rearrangement term is indispensable. In this work, we derive the rearrangement term for hyperon potentials with arbitrary density- dependence. The importance of the rearrangement term is also exhibited in numerical instances.
文摘Esfenvalerate belongs to the pyrethroid group of insecticides which display significant selective toxicity against insects compared to mammalian species, nevertheless, they may pose health risks, especially in case of accidental exposure. The aim of the present study was to model the effect of acute, relatively high-dose exposure of the esfenvalerate-containing formulation Sumi-Alpha?. Eventual functional alterations in the central nervous system and in the gastrointestinal tract were studied on in vitro tissue preparations at different delays after intragastric administration to rats. Neuronal effects were characterized by field potential recording in cortical and hippocampal brain slices, while gastrointestinal effects were examined by analyzing the motility and excitability of isolated ileum segments. On the brain slices originating from esfenvalerate-treated animals, changes in excitability of both inhibitory and excitatory type could be observed. Voltage thresholds necessary to evoke responses in neocortex slices were elevated, and population spike amplitudes were lower in hippocampal slices. However, epileptiform potentials with pronounced late components were also observed. A decreased long-term potentiation (LTP) could be seen in both brain areas after esfenvalerate treatment. Seizure susceptibility of the slices was not significantly altered, but tended to be somewhat higher in slices originating from treated rats. In ileum segments, both spontaneous and acetyl-choline (ACh)-elicited contractions were modified by treatment. Esfenvalerate raised the amplitude of contractions in the low ACh concentration range. However, the solvent xylene also considerably contributed to the detected changes. We can conclude that a relatively high, single oral dose of Sumi-Alpha? exerted mild and temporary effects on the elementary brain functions and intestine functions of the rat.
文摘This paper reports the intrinsic-structure DC characteristics computed from the analytical electrochemical current theory of the bipolar field-effect transistor （BiFET） with two identical MOS gates on nanometer-thick pure-base of silicon with no generation-recombination-trapping. Numerical solutions are rapidly obtained for the three potential variables,electrostatic and electron and hole electrochemical potentials,to give the electron and hole surface and volume channel currents,using our cross-link two-route or zig-zag one-route recursive iteration algorithms. Boundary conditions on the three potentials dominantly affect the intrinsic-structure DC characteristics,illustrated by examples covering 20-decades of current （10-22 to 10-2 A/Square at 400cm^2/（V · s） mobility for 1.5nm gate-oxide, and 30nm-thick pure-base）. Aside from the domination of carrier space-charge-limited drift current in the strong surface channels,observed in the theory is also the classical drift current saturation due to physical pinch-off of an impure-base volume channel depicted by the 1952 Shockley junction-gate field-effect transistor theory,and its extension to complete cut-off of the pure-base volume channel,due to vanishing carrier screening by the few electron and hole carriers in the pure-base,with Debye length （25mm） much larger than device dimension （25nm）.
