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The standard conception of cardiac conduction is based on the cable theory of nerve conduction, which treats cardiac tissue as a continuous syncytium described by the Hodgkin–Huxley equations. However, cardiac tissue is composed of discretized cells with microscopic and macroscopic heterogeneities and discontinuities, such as subcellular localizations of sodium channels and connexins. In addition to this, there are heterogeneities in the distribution of sympathetic and parasympathetic nerves, which powerfully regulate impulse propagation. In the continuous models, the ultrastructural details, i.e. the microscopic heterogeneities and discontinuities, are ignored by ‘coarse graining’ or ‘smoothing’. However, these ultrastructural components may play crucial roles in cardiac conduction and arrhythmogenesis, particularly in disease states. We discuss the current progress of modelling the effects of ultrastructural components on electrical conduction, the issues and challenges faced by the cardiac modelling community, and how to scale up conduction properties at the subcellular (microscopic) scale to the tissue and whole‐heart (macroscopic) scale in future modelling and experimental studies, i.e. how to link the ultrastructure at different scales to impulse conduction and arrhythmogenesis in the heart. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The rational utilization of energy is an important issue for sustainable development. Electrically coupled integrated energy systems can enhance energy utilization efficiency and reduce energy costs. However, traditional integrated energy system optimization has problems with local optima and slow convergence speed, which cannot fully utilize energy resources. Therefore, this study proposes an improved electrical coupling integrated energy system on the ground of particle swarm optimization algorithm. In response to the problems of local optima and slow convergence speed in traditional optimization algorithms, particle swarm optimization algorithm is introduced for system optimization. By combining PSO with simulated annealing algorithm, the possibility of PSO in global optimization is reduced. The local search ability of PSO and the global search ability of simulated annealing algorithm are used to find the optimal solution. The particle swarm optimization algorithm is used for preliminary search. When the particle falls into the local optimal, the simulated annealing algorithm is introduced for global search, and the particle is guided to jump out of the local optimal and continue searching. The experiment demonstrates that the improved algorithm has certain advantages in solving test functions. The variance, mean, and optimal values are 0.00125, 0.13874, and 0.105531, respectively, which are all better than the particle swarm optimization algorithm. The simulated annealing algorithm improved the particle swarm optimization algorithm with a high accuracy index, which eventually stabilized above 0.9, and the recall index also remained above 0.8. After 100 iterations, it had already fallen into a local optimal solution. By applying the improved hybrid optimization algorithm to the electrically-coupled integrated energy system, the distribution of various energy sources can be managed and optimized more effectively, and the overall performance of the system can be improved. Especially when dealing with complex energy scheduling and distribution problems, the algorithm can provide more stable, efficient and reliable solutions. This study can achieve efficient operation and optimized scheduling of integrated energy systems, reduce energy consumption and environmental pollution, and reduce energy costs. And it can improve the reliability and stability of energy supply, which has important application value and research significance.

When systems experience a severe fault, splitting, as the final line of defense to ensure the stability of the power system, holds immense significance. The precise selection of splitting sections has become the current focal point of research. Addressing the challenges of a large search space and unclear splitting sections, this paper introduces a grid structure optimization algorithm based on electrical coupling degree. Firstly, employing the theory of slow coherency, a generalized characteristic analysis of the system is conducted, leading to an initial division of coherency groups. Subsequently, an electrical coupling degree index, taking into account the inertia of generators, is proposed. This index can reflect the clarity of grid splitting. Furthermore, a two-layer optimization model for grid structure is constructed, utilizing the Proximal Policy Optimization (PPO) algorithm to optimize the grid structure. This process reduces the size of the splitting space and mitigates the difficulty of acquiring splitting sections. Finally, simulation validation is performed using the IEEE-118-bus system to demonstrate the effectiveness of the proposed optimization algorithm. [ABSTRACT FROM AUTHOR]

This paper firstly establishes the mathematical models of electric networks, natural gas networks and electrically coupled equipment, respectively, and models them comprehensively to form the basic architecture of an electrically coupled integrated energy system. Based on this, an integrated energy system planning model based on the ARIMA-LSTM model is proposed, and the objective function is optimized. Among them, the ARIMA model is used to fix the order of the objective function, and the LSTM model is used to train the backpropagation of the error of the objective function. Finally, the effectiveness of electrical cost planning and CO2 emission planning is verified by simulation experiments under two scenarios. The results show that scenario 1 saves $79,799.8 in electricity cost and reduces 11,612 t of CO2 emissions compared with scenario 2, which is not configured with an electrically coupled integrated energy system. The research in this paper provides new ideas and methods for the planning of electrically coupled integrated energy systems, which have certain academic value and application prospects.

In this study, the electrical characteristics and electrical coupling effect for monolithic 3-dimensional nonvolatile memory consisting of a feedback field-effect transistor (M3D-NVM-FBFET) were investigated using technology computer-aided design. The M3D-NVM-FBFET consists of an N-type FBFET with an oxide–nitride–oxide layer and a metal–oxide–semiconductor FET (MOSFET) in the top and bottom tiers, respectively. For the memory simulation, the programming and erasing voltages were applied at 18 and −18 V for 1 μs, respectively. The memory window of the M3D-NVM-FBFET was 1.98 V. As the retention simulation was conducted for 10 years, the memory window decreased from 1.98 to 0.83 V. For the M3D-NVM-FBFET, the electrical coupling that occurs through an electrical signal in the bottom-tier transistor was investigated. As the thickness of the interlayer dielectric (TILD) decreases from 100 to 10 nm, the change in the VTH increases from 0.16 to 0.87 V and from 0.15 to 0.84 V after the programming and erasing operations, respectively. M3D-NVM-FBFET circuits with a thin TILD of 50 nm or less need to be designed considering electrical coupling. [ABSTRACT FROM AUTHOR]

• Connexin36 is highly expressed in sympathetic preganglionic neurons (SPNs). • Connnexin36 is detected along the entire length of the spinal thoracic intermediolateral cell column. • The IML contains glutamatergic and GABAergic terminals that are eGFP+ in Cx36BAC::eGFP mice. • SPNs are innervated by eGFP+ terminals in Cx36BAC::eGFP mice. Spinal sympathetic preganglionic neurons (SPNs) are among the many neuronal populations in the mammalian central nervous system (CNS) where there is evidence for electrical coupling between cell pairs linked by gap junctions composed of connexin36 (Cx36). Understanding the organization of this coupling in relation to autonomic functions of spinal sympathetic systems requires knowledge of how these junctions are deployed among SPNs. Here, we document the distribution of immunofluorescence detection of Cx36 among SPNs identified by immunolabelling of their various markers, including choline acetyltransferase, nitric oxide and peripherin in adult and developing mouse and rat. In adult animals, labelling of Cx36 was exclusively punctate and dense concentrations of Cx36-puncta were distributed along the entire length of the spinal thoracic intermediolateral cell column (IML). These puncta were also seen in association with SPN dendritic processes in the lateral funiculus, the intercalated and central autonomic areas and those within and extending medially from the IML. All labelling for Cx36 was absent in spinal cords of Cx36 knockout mice. High densities of Cx36-puncta were already evident among clusters of SPNs in the IML of mouse and rat at postnatal days 10–12. In Cx36BAC::eGFP mice, eGFP reporter was absent in SPNs, thus representing false negative detection, but was localized to some glutamatergic and GABAergic synaptic terminals. Some eGFP+ terminals were found contacting SPN dendrites. These results indicate widespread Cx36 expression in SPNs, further supporting evidence of electrical coupling between these cells, and suggest that SPNs are innervated by neurons that themselves may be electrically coupled. [ABSTRACT FROM AUTHOR]

Excitation‐coupling (ECC) is paramount for coordinated contraction to maintain sufficient cardiac output. The study of ECC regulation has primarily been limited to cardiomyocytes (CMs), which conduct voltage waves via calcium fluxes from one cell to another, eliciting contraction of the atria followed by the ventricles. CMs rapidly transmit ionic flux via gap junction proteins, predominantly connexin 43. While the expression of connexin isoforms has been identified in each of the individual cell populations comprising the heart, the formation of gap junctions with nonmuscle cells (i.e., macrophages and Schwann cells) has gained new attention. Evaluating nonmuscle contributions to ECC in vivo or in situ remains difficult and necessitates the development of simple, yet biomimetic in vitro models to better understand and prevent physiological dysfunction. Standard 2D cell culture often consists of homogenous cell populations and lacks the dynamic mechanical environment of native tissue, confounding the phenotypic and proteomic makeup of these highly mechanosensitive cell populations in prolonged culture conditions. This review will highlight the recent developments and the importance of new microphysiological systems to better understand the complex regulation of ECC in cardiac tissue. [ABSTRACT FROM AUTHOR]

When systems experience a severe fault, splitting, as the final line of defense to ensure the stability of the power system, holds immense significance. The precise selection of splitting sections has become the current focal point of research. Addressing the challenges of a large search space and unclear splitting sections, this paper introduces a grid structure optimization algorithm based on electrical coupling degree. Firstly, employing the theory of slow coherency, a generalized characteristic analysis of the system is conducted, leading to an initial division of coherency groups. Subsequently, an electrical coupling degree index, taking into account the inertia of generators, is proposed. This index can reflect the clarity of grid splitting. Furthermore, a two-layer optimization model for grid structure is constructed, utilizing the Proximal Policy Optimization (PPO) algorithm to optimize the grid structure. This process reduces the size of the splitting space and mitigates the difficulty of acquiring splitting sections. Finally, simulation validation is performed using the IEEE-118-bus system to demonstrate the effectiveness of the proposed optimization algorithm.

Electrical coupling between neurons is broadly present across brain areas and is typically assumed to synchronize network activity. However, intrinsic properties of the coupled cells can complicate this simple picture. Many cell types with electrical coupling show a diversity of post-spike subthreshold fluctuations, often linked to subthreshold resonance, which are transmitted through electrical synapses in addition to action potentials. Using the theory of weakly coupled oscillators, we explore the effect of both subthreshold and spike-mediated coupling on synchrony in small networks of electrically coupled resonate-and-fire neurons, a hybrid neuron model with damped subthreshold oscillations and a range of post-spike voltage dynamics. We calculate the phase response curve using an extension of the adjoint method that accounts for the discontinuous post-spike reset rule. We find that both spikes and subthreshold fluctuations can jointly promote synchronization. The subthreshold contribution is strongest when the voltage exhibits a significant post-spike elevation in voltage, or plateau potential. Additionally, we show that the geometry of trajectories approaching the spiking threshold causes a "reset-induced shear" effect that can oppose synchrony in the presence of network asymmetry, despite having no effect on the phase-locking of symmetrically coupled pairs.

In this study, the electrical characteristics and electrical coupling effect for monolithic 3-dimensional nonvolatile memory consisting of a feedback field-effect transistor (M3D-NVM-FBFET) were investigated using technology computer-aided design. The M3D-NVM-FBFET consists of an N-type FBFET with an oxide–nitride–oxide layer and a metal–oxide–semiconductor FET (MOSFET) in the top and bottom tiers, respectively. For the memory simulation, the programming and erasing voltages were applied at 18 and −18 V for 1 μs, respectively. The memory window of the M3D-NVM-FBFET was 1.98 V. As the retention simulation was conducted for 10 years, the memory window decreased from 1.98 to 0.83 V. For the M3D-NVM-FBFET, the electrical coupling that occurs through an electrical signal in the bottom-tier transistor was investigated. As the thickness of the interlayer dielectric (TILD) decreases from 100 to 10 nm, the change in the VTH increases from 0.16 to 0.87 V and from 0.15 to 0.84 V after the programming and erasing operations, respectively. M3D-NVM-FBFET circuits with a thin TILD of 50 nm or less need to be designed considering electrical coupling.

Accurate power load forecasting is the key foundation and important premise of urban power system planning. Considering that urban power load demand is closely related to economic development and meteorological conditions, and with the application and promotion of various energy coupling equipment and the promotion of electric energy substitution policy, the relationship between gas load and power load demand is increasing. However, most of the existing load forecasting methods only consider a single economic factor or a single meteorological factor, and fail to combine the coupling and complementarity between loads. Based on this, this paper first analyzes the coupling characteristics between power load and urban economic, meteorological, and gas load with Copula theory; Secondly, the key parameters of the least squares support vector machine (LSSVM) are solved by using the salp swarm algorithm (SSA), and the urban monthly power load forecasting model based on SSA-LSSVM is established; Finally, based on the macroeconomic data, meteorological observation data and monthly electrical load of a city in North China, the prediction model is verified. Through comparison with different prediction scenarios, it is confirmed that the built model can effectively improve the prediction accuracy and has good application effects. [ABSTRACT FROM AUTHOR]

A monolithic three-dimensional integrated static random access memory containing a feedback field effect transistor (M3D-FBFET-SRAM) was proposed. The M3D-FBFET-SRAM cell consists of one metal oxide semiconductor field effect transistor (MOSFET) and one FBFET, and each transistor is located on the top tier and one on the bottom tier in a monolithic 3D integration, respectively. The electrical characteristics and operation of the NFBFET in the M3D-FBFET-SRAM cell were investigated using a TCAD simulator. For SRAM operation, the optimum doping profile of the NFBFET was used for non-turn-off characteristics. For the M3D-FBFET-SRAM cell, the operation of the SRAM and electrical coupling occurring between the top and bottom tier transistor were investigated. As the thickness of interlayer dielectric decreases, the reading 'ON' current decreases. To prevent performance degradation, two ways to compensate for current level were suggested. [ABSTRACT FROM AUTHOR]

The effect of the work-function variation (WFV) of metal-oxide-semiconductor field-effect transistor (MOSFET) gates on a monolithic 3D inverter (M3DINV) structure is investigated in the current paper. The M3DINV has a structure in which MOSFETs are sequentially stacked. The WFV effect of the top- and bottom-tier gates on the M3DINV is investigated using technology computer-aided design (TCAD) and a Monte-Carlo sampling simulation of TCAD. When the interlayer dielectric thickness (TILD) changes from 5 to 100 nm, electrical parameters, such as the threshold voltage, subthreshold swing, on-current, and off-current of the top-tier N-MOSFET and the parameter changes by the change in gate voltage of the bottom-tier P-MOSFET, are investigated. As TILD decreases below about 30 nm, the means and standard deviations of the electrical parameters rapidly increase. This means that the coupling and its distribution are relatively large in the regime and thus should be well considered for M3D circuit simulation. In addition, due to the increase in standard deviation, the WFV effect of both the top- and bottom-tier MOSFET gates was observed to be greater than those of only the top-tier MOSFET gates and only the bottom-tier MOSFET gates. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (CQDs) are promising materials for building next-generation solution-processed, high-performance, and low-cost optoelectronic devices. The photoelectric properties of the resulting films are not only determined by the intrinsic characteristics of the CQDs but are also significantly affected by the electrical coupling between them. However, enhancing the electrical coupling in CQD-based films is still a big challenge. In this work, a two-step ligand exchange strategy has been conducted to solve the above issue, where the InZnP@PbS CQDs have been used as the case. First, the Meerwein salt (Et 3 OBF 4) solution in N, N -dimethylformamide (DMF) has been employed to peel off the native ligands that are strongly capped on the surface of oil-soluble CQDs, resulting in a neat surface. Second, iodide ions are linked to the neat surface of the CQDs to narrow the distance between them and passivate their defects, establishing strong electrical coupling. Transient surface photovoltage (TSPV) and photo-conductance tests confirm that the resulting InZnP@PbS–I CQDs films possess good photoelectric properties and stability. In the fabricated solid-state solar cells, 3.1 % of the photoelectric conversion efficiency (PCE) has been achieved under 1 sun. The current results are outstanding for III-V group CQD-based all solid-state solar cells. • Fabricating the III-V group InZnP CQDs coated with PbS shell. • Two-step exchanges the ligands that strongly capped on the surface of CQDs. • Establishing strong electrical coupling between the InZnP@PbS CQDs in films. • Boosting the performance of InP CQD-based solid-state solar cells. [ABSTRACT FROM AUTHOR]

This article presents a substrate integrated waveguide (SIW) filter power divider (FPD) based on glass substrate with a wide stopband. Couplings of TE101 and TE103 modes construct the passband of the FPD, which are transmitted by a T-type structure with resonators of different sizes to reduce parasitic patterns. The input and output ports are realized by electrical feeders, which penetrate into the center of resonant cavity. Combined with the lateral coupling structure, the parasitic passband caused by the even-high-order modes can be eliminated effectively. Utilizing the multimode transmission characteristics of waveguide resonators, electromagnetic waves of two modes are set to transmit in resonators of different sizes, effectively suppressing the resonance of higher order modes. In order to achieve a good isolation, an isolation resistor is introduced between two output ports to ensure the high efficiency of signal transmission. Consequently, an FPD with a center frequency of 35.5 GHz, a bandwidth of 1 GHz, and out-of-band suppression greater than six times the center frequency is designed, fabricated, and measured. Both theory and experiment have proved the effectiveness of the above method, and the simulation results are in good agreement with the measured results. [ABSTRACT FROM AUTHOR]

Inhibitory fast‐spiking interneurons in the dorsal striatum regulate actions and action strategies, including habits. Fast‐spiking interneurons are widely believed to synchronize their firing due to the electrical synapses formed between these neurons. However, neuronal modelling data suggest convergent cortical input may also drive synchrony in fast‐spiking interneuron networks. To better understand how fast‐spiking interneuron synchrony arises, we performed dual whole‐cell patch clamp electrophysiology experiments to inform a simple Bayesian network modelling cortico‐fast‐spiking interneuron circuitry. Dual whole‐cell patch clamp electrophysiology revealed that while responsivity to corticostriatal input activation was high in fast‐spiking interneurons, few of these neurons exhibited electrical coupling in adult mice. In simulations of a cortico‐fast‐spiking interneuron network informed by these data, the degree of glutamatergic cortical convergence onto fast‐spiking interneurons significantly increased fast‐spiking interneuron synchronization while manipulations of electrical coupling between these neurons exerted relatively little impact. These results suggest that the primary source of functional coordination of fast‐spiking interneuron activity in adulthood arises from convergent corticostriatal input activation. Key points: Electrical synapses between striatal fast‐spiking interneurons in adult mice occur in ∼8% of assayed pairs.Coincident, convergent cortical input onto fast‐spiking interneurons significantly contributes to fast‐spiking interneuron synchrony.Electrical synapses between fast‐spiking interneurons provide only minor enhancement of fast‐spiking interneuron synchrony.These results suggest a mechanism by which adult mouse fast‐spiking interneurons of the striatum synchronize in the face of declining expression of the electrical synapse‐forming connexin‐36 protein. [ABSTRACT FROM AUTHOR]

Cardiac fibroblasts constitute a major cell population in the heart. They secrete extracellular matrix components and various other factors shaping the microenvironment of the heart. In silico analysis of intercellular communication based on single-cell RNA sequencing revealed that fibroblasts are the source of the majority of outgoing signals to other cell types. This observation suggests that fibroblasts play key roles in orchestrating cellular interactions that maintain organ homeostasis but that can also contribute to disease states. Here, we will review the current knowledge of fibroblast interactions in the healthy, diseased, and aging heart. We focus on the interactions that fibroblasts establish with other cells of the heart, specifically cardiomyocytes, endothelial cells and immune cells, and particularly those relying on paracrine, electrical, and exosomal communication modes. [ABSTRACT FROM AUTHOR]

Molecular layer interneurons (MLIs) account for approximately 80% of the inhibitory interneurons in the cerebellar cortex and are vital to cerebellar processing. MLIs are thought to primarily inhibit Purkinje cells (PCs) and suppress the plasticity of synapses onto PCs. MLIs also inhibit, and are electrically coupled to, other MLIs, but the functional significance of these connections is not known. Here, we find that two recently recognized MLI subtypes, MLI1 and MLI2, have a highly specialized connectivity that allows them to serve distinct functional roles. MLI1s primarily inhibit PCs, are electrically coupled to each other, fire synchronously with other MLI1s on the millisecond timescale in vivo , and synchronously pause PC firing. MLI2s are not electrically coupled, primarily inhibit MLI1s and disinhibit PCs, and are well suited to gating cerebellar-dependent behavior and learning. The synchronous firing of electrically coupled MLI1s and disinhibition provided by MLI2s require a major re-evaluation of cerebellar processing. [Display omitted] • Cerebellar molecular layer interneurons consist of two subtypes, MLI1 and MLI2 • MLI1s are electrically coupled, fire synchronously, and mainly inhibit Purkinje cells • MLI2s do not fire synchronously, mainly inhibit MLI1s, and disinhibit Purkinje cells • The study suggests that MLI subtypes differentially regulate cerebellar output and plasticity Lackey et al. show that molecular layer interneurons comprise two subtypes with distinct connectivity that are suited to serve different roles. MLI1s are electrically coupled, tend to fire synchronously, and preferentially inhibit Purkinje cells, whereas MLI2s are not electrically coupled, primarily inhibit MLI1s, and disinhibit Purkinje cells. [ABSTRACT FROM AUTHOR]

A monolithic three-dimensional integrated static random access memory containing a feedback field effect transistor (M3D-FBFET-SRAM) was proposed. The M3D-FBFET-SRAM cell consists of one metal oxide semiconductor field effect transistor (MOSFET) and one FBFET, and each transistor is located on the top tier and one on the bottom tier in a monolithic 3D integration, respectively. The electrical characteristics and operation of the NFBFET in the M3D-FBFET-SRAM cell were investigated using a TCAD simulator. For SRAM operation, the optimum doping profile of the NFBFET was used for non-turn-off characteristics. For the M3D-FBFET-SRAM cell, the operation of the SRAM and electrical coupling occurring between the top and bottom tier transistor were investigated. As the thickness of interlayer dielectric decreases, the reading ‘ON’ current decreases. To prevent performance degradation, two ways to compensate for current level were suggested.

The effect of the work-function variation (WFV) of metal-oxide-semiconductor field-effect transistor (MOSFET) gates on a monolithic 3D inverter (M3DINV) structure is investigated in the current paper. The M3DINV has a structure in which MOSFETs are sequentially stacked. The WFV effect of the top- and bottom-tier gates on the M3DINV is investigated using technology computer-aided design (TCAD) and a Monte-Carlo sampling simulation of TCAD. When the interlayer dielectric thickness (TILD) changes from 5 to 100 nm, electrical parameters, such as the threshold voltage, subthreshold swing, on-current, and off-current of the top-tier N-MOSFET and the parameter changes by the change in gate voltage of the bottom-tier P-MOSFET, are investigated. As TILD decreases below about 30 nm, the means and standard deviations of the electrical parameters rapidly increase. This means that the coupling and its distribution are relatively large in the regime and thus should be well considered for M3D circuit simulation. In addition, due to the increase in standard deviation, the WFV effect of both the top- and bottom-tier MOSFET gates was observed to be greater than those of only the top-tier MOSFET gates and only the bottom-tier MOSFET gates.

The sensitivity of the LM139A quad voltage comparator toward simultaneous single-event transient has been investigated through laser single photon absorption. The results have been supported and compared to heavy-ion tests. The analysis of sensitivity leads to the observation of two sensitive cases related to internal charge-sharing mechanism between comparator function and input line coupling effects. [ABSTRACT FROM AUTHOR]

Electrical synaptic transmission relies on neuronal gap junctions containing channels constructed by Connexins. While at chemical synapses neurotransmitter-gated ion channels are critically supported by scaffolding proteins, it is unknown if channels at electrical synapses require similar scaffold support. Here, we investigated the functional relationship between neuronal Connexins and Zonula Occludens 1 (ZO1), an intracellular scaffolding protein localized to electrical synapses. Using model electrical synapses in zebrafish Mauthner cells, we demonstrated that ZO1 is required for robust synaptic Connexin localization, but Connexins are dispensable for ZO1 localization. Disrupting this hierarchical ZO1/Connexin relationship abolishes electrical transmission and disrupts Mauthner cell-initiated escape responses. We found that ZO1 is asymmetrically localized exclusively postsynaptically at neuronal contacts where it functions to assemble intercellular channels. Thus, forming functional neuronal gap junctions requires a postsynaptic scaffolding protein. The critical function of a scaffolding molecule reveals an unanticipated complexity of molecular and functional organization at electrical synapses.

We examine the effects of dendritic filtering on the existence, stability, and robustness of phase-locked states to heterogeneity and noise in a pair of electrically coupled ball-and-stick neurons with passive dendrites. We use the theory of weakly coupled oscillators and analytically derived filtering properties of the dendritic coupling to systematically explore how the electrotonic length and diameter of dendrites can alter phase-locking. In the case of a fixed value of the coupling conductance (gc) taken from the literature, we find that repeated exchanges in stability between the synchronous and anti-phase states can occur as the electrical coupling becomes more distally located on the dendrites. However, the robustness of the phase-locked states in this case decreases rapidly towards zero as the distance between the electrical coupling and the somata increases. Published estimates of gc are calculated from the experimentally measured coupling coefficient (CC) based on a single-compartment description of a neuron, and therefore may be severe underestimates of gc. With this in mind, we re-examine the stability and robustness of phase-locking using a fixed value of CC, which imposes a limit on the maximum distance the electrical coupling can be located away from the somata. In this case, although the phase-locked states remain robust over the entire range of possible coupling locations, no exchanges in stability with changing coupling position are observed except for a single exchange that occurs in the case of a high somatic firing frequency and a large dendritic radius. Thus, our analysis suggests that multiple exchanges in stability with changing coupling location are unlikely to be observed in real neural systems.

• Gap junction-mediated inter-neuronal communication is regulated by mGluRs. • mGluRs trigger long-term changes in electrical synaptic transmission. • mGluR actions on electrical synapses might also involve other neurotransmitters. • These interactions play relevant roles during neurodevelopment and brain injury. Variations of synaptic strength are thought to underlie forms of learning and can functionally reshape neural circuits. Metabotropic glutamate receptors play key roles in regulating the strength of chemical synapses. However, information within neural circuits is also conveyed via a second modality of transmission: gap junction-mediated synapses. We review here evidence indicating that metabotropic glutamate receptors also play important roles in the regulation of synaptic communication mediated by neuronal gap junctions, also known as 'electrical synapses'. Activity-driven interactions between metabotropic glutamate receptors and neuronal gap junctions can lead to long-term changes in the strength of electrical synapses. Further, the regulatory action of metabotropic glutamate receptors on neuronal gap junctions is not restricted to adulthood but is also of critical relevance during brain development and contributes to the pathological mechanisms that follow brain injury. [ABSTRACT FROM AUTHOR]

Gap junctions are ubiquitous within the retina, but in general, it remains to be determined whether gap junction coupling between specific cell types is sufficiently strong to mediate functionally relevant coupling via electrical synapses. From ultrastructural, tracer coupling and immunolabeling studies, there is clear evidence for gap junctions between cone bipolar cells, but it is not known if these gap junctions function as electrical synapses. Here, using whole-cell voltage-clamp recording in rat (male and female) retinal slices, we investigated whether the gap junctions of bipolar cells make a measurable contribution to the membrane properties of these cells. We measured the input resistance (RN) of bipolar cells before and after applying meclofenamic acid (MFA) to block gap junctions. In the presence of MFA, RN of ON-cone bipolar cells displayed a clear increase, paralleled by block of the electrical coupling between these cells and AII amacrine cells in recordings of coupled cell pairs. For OFF-cone and rod bipolar cells, RN did not increase in the presence of MFA. The results for rod bipolar cells are consistent with the lack of gap junctions in these cells. However, for OFF-cone bipolar cells, our results suggest that the morphologically identified gap junctions between these cells do not support a junctional conductance that is sufficient to mediate effective electrical coupling. Instead, these junctions might play a role in chemical and/or metabolic coupling between subcellular compartments. [ABSTRACT FROM AUTHOR]

Background: Granule cells in the hippocampus project axons to hippocampal CA3 pyramidal cells where they form large mossy fiber terminals. We have reported that these terminals contain the gap junction protein connexin36 (Cx36) specifically in the stratum lucidum of rat ventral hippocampus, thus creating morphologically mixed synapses that have the potential for dual chemical/electrical transmission., Methodology: Here, we used various approaches to characterize molecular and electrophysiological relationships between the Cx36-containing gap junctions at mossy fiber terminals and their postsynaptic elements and to examine molecular relationships at mixed synapses in the brainstem., Results: In rat and human ventral hippocampus, many of these terminals, identified by their selective expression of vesicular zinc transporter-3 (ZnT3), displayed multiple, immunofluorescent Cx36-puncta representing gap junctions, which were absent at mossy fiber terminals in the dorsal hippocampus. In rat, these were found in close proximity to the protein constituents of adherens junctions (i.e., N-cadherin and nectin-1) that are structural hallmarks of mossy fiber terminals, linking these terminals to the dendritic shafts of CA3 pyramidal cells, thus indicating the loci of gap junctions at these contacts. Cx36-puncta were also associated with adherens junctions at mixed synapses in the brainstem, supporting emerging views of the structural organization of the adherens junction-neuronal gap junction complex. Electrophysiologically induced long-term potentiation (LTP) of field responses evoked by mossy fiber stimulation was greater in the ventral than dorsal hippocampus., Conclusions: The electrical component of transmission at mossy fiber terminals may contribute to enhanced LTP responses in the ventral hippocampus., Competing Interests: None., (IJPPP Copyright © 2024.)

In this paper, we investigated the electrical coupling between the top and bottom transistors in a monolithic 3-dimensional (3D) inverter (M3INV) stacked vertically with junctionless field-effect transistor (JLFET), which is one of candidates to replace metal-oxide-semiconductor field-effect transistors (MOSFET). Currents, transconductances, and gate capacitances of the top N-type transistor at the different gate voltages of the bottom P-type transistor as a function of thickness of inter-layer dielectric (TILD) and gate channel length (Lg) are simulated using technology computer-aided-design (TCAD). In M3INV stacked vertically with MOSFET (M3INV-MOS) and JLFET (M3INV-JL), the variations of threshold voltage, transconductance, and capacitance increase as TILD decreases and they increase as Lg increases, and thus there is a strong coupling in M3INV at the range of TILD ≤ 30 nm. In M3INV, the coupling between stacked JLFETs in M3INV-JL is larger than that between MOSFETs in M3INV-MOS at the same TILD and Lg. The switching threshold voltage (Vm) and noise margins (NMs) of M3INV are calculated from the voltage transfer characteristics (VTC) simulated with TCAD mixed-mode. As the gate lengths of M3INV-MOS and M3INV-JL increase, the Vm variations increase and decrease, respectively. The smaller the gate lengths of M3INV-NOS and M3INV-JL, the larger and smaller the variation of Vm, respectively. The noise margin of M3INV-MOS is larger and better for inverter characteristics than one of M3INV-JL. M3INV-MOS has less electrical coupling than M3INV-JL. [ABSTRACT FROM AUTHOR]

Aluminium-based composite processed with spark plasma sintering was modelled with COMSOL Multiphysics. This was aimed at investigating the effect of the SPS process parameters on thermal and mechanical stresses induced in the sintered Al-CNTs-Nb composite samples. The modelling employed optimal parameters used in the laboratory to fabricate the samples. The physics included electro-thermo-mechanical coupling. The geometry was 2D axisymmetric while the parameters were based on temperature-dependent properties. Only the consolidated sample was modelled and simulated to simplify the modelling. Results obtained showed that the simultaneous heating and application of pressure enhanced the sintering efficiency and the properties of the product. The least von Mises stress as well as least thermal stress were obtained at a pressure of 30 MPa as against 20 MPa and 10 MPa. This implied that higher pressure produced lower stresses. Therefore, it can be concluded that high sintering pressure reduces mechanical and thermal stresses and improves the properties of the composite. [ABSTRACT FROM AUTHOR]

In this paper, we focus on the emergence of diverse neuronal oscillations arising in a mixed population of neurons with different excitability properties. These properties produce mixed mode oscillations (MMOs) characterized by the combination of large amplitudes and alternate subthreshold or small amplitude oscillations. Considering the biophysically plausible, Izhikevich neuron model, we demonstrate that various MMOs, including MMBOs (mixed mode bursting oscillations) and synchronized tonic spiking appear in a randomly connected network of neurons, where a fraction of them is in a quiescent (silent) state and the rest in self-oscillatory (firing) states. We show that MMOs and other patterns of neural activity depend on the number of oscillatory neighbors of quiescent nodes and on electrical coupling strengths. Our results are verified by constructing a reduced-order network model and supported by systematic bifurcation diagrams as well as for a small-world network. Our results suggest that, for weak couplings, MMOs appear due to the de-synchronization of a large number of quiescent neurons in the networks. The quiescent neurons together with the firing neurons produce high frequency oscillations and bursting activity. The overarching goal is to uncover a favorable network architecture and suitable parameter spaces where Izhikevich model neurons generate diverse responses ranging from MMOs to tonic spiking. [ABSTRACT FROM AUTHOR]

Gap junctions are physical channels that connect adjacent cells, permitting the flow of small molecules/ions between the cytoplasms of the coupled units. Innexin/innexin-like proteins are responsible for the formation of invertebrate gap junctions. Within the nervous system, gap junctions often function as electrical synapses, providing a means for coordinating activity among electrically coupled neurons. While some gap junctions allow the bidirectional flow of small molecules/ions between coupled cells, others permit flow in one direction only or preferentially. The complement of innexins present in a gap junction determines its specific properties. Thus, understanding innexin diversity is key for understanding the full potential of electrical coupling in a species/system. The decapod crustacean cardiac ganglion (CG), which controls cardiac muscle contractions, is a simple pattern-generating neural network with extensive electrical coupling among its circuit elements. In the lobster, Homarus americanus, prior work suggested that the adult neuronal innexin complement consists of six innexins (Homam-Inx1-4 and Homam-Inx6-7). Here, using a H. americanus CG-specific transcriptome, we explored innexin complement in this portion of the lobster nervous system. With the exception of Homam-Inx4, all of the previously described innexins appear to be expressed in the H. americanus CG. In addition, transcripts encoding seven novel putative innexins (Homam-Inx8-14) were identified, four (Homam-Inx8-11) having multiple splice variants, e.g., six for Homam-Inx8. Collectively, these data indicate that the innexin complement of the lobster nervous system in general, and the CG specifically, is likely significantly greater than previously reported, suggesting the possibility of expanded gap junction diversity and function in H. americanus. [ABSTRACT FROM AUTHOR]

This paper presents a simple and nondestructive method to determine doping densities and built‐in potential of subcells by adapting the well‐known capacitance‐voltage (C‐V) technique to two‐terminal (2 T) tandem solar cells. Because of the electrical coupling between the two subcells in a monolithic 2 T tandem solar cell, the standard method using a Mott‐Schottky plot (1/C2 vs V) cannot be applied. Using numerical modeling, it is demonstrated that, by under chosen illumination conditions where only one subcell can absorb the light, it is possible to explore the bias dependence of the capacitance and to extract the parameters of the other subcell if the appropriate frequency conditions are present. This method is experimentally applied to an AlGaAs/Si tandem cell, and parameters of both AlGaAs and Si cells are extracted. Finally, the validity of that method is assessed by the very good agreement obtained when comparing the values extracted from our measurements on the tandem cell to those extracted from measurements on isotype cells and to the values targeted during the fabrication process of the AlGaAs/Si tandem solar cell. [ABSTRACT FROM AUTHOR]

The electrical activity of neurons depends on the physiological conditions in the nervous system. An electromagnetic field, for example, can significantly affect the dynamics of individual neural cells, and it also affects their collective dynamics. It is therefore of interest to study the neuronal dynamics under such an influence in various setups. We thus study the firing patterns in two coupled neurons by considering three different types of synapses, namely electrical, chemical, and electrochemical. We use the Hindmarsh–Rose mathematical model as the basis of neuronal dynamics, and we also introduce an electromagnetic field effect. We conduct extensive calculations of the firing patterns, and we determine the bifurcation diagrams for constant and periodic external currents. The results show that the different synaptic connections evoke different firing patterns and that in general electrochemical synapses can show richer variety of dynamical behavior than electrical or chemical synapses. [ABSTRACT FROM AUTHOR]

The attenuation performance of an electromagnetic interference filter can be significantly degraded by coupling, parasitics, and frequency-dependent nonlinearity, especially in high frequency (HF) range. This article reveals and investigates a mutual capacitive coupling effect in the popular filter structures with T-shaped joint. The mechanism is explained and the impact on filter attenuation is analyzed, which show this coupling is the dominant cause of performance degradation of T-shaped filters and a major cause for other T-shape-related filters. The effect patterns for both common-mode (CM) and differential-mode (DM) filters are analytically derived and further examined in multistage filter structures. Mitigation solutions using PCB slits and grounded shielding are proposed to improve filter transfer gain up to 30 dB in the HF range. A topological strategy is also presented, further enhancing filter attenuation. In addition, the impact of relative positions of the inductors on the coupling capacitance is discussed, and five positions are experimentally studied and compared. Experimental results obtained from three-phase LCL and LCLC filters verify the significance of this coupling and the effectiveness of the mitigation methods. [ABSTRACT FROM AUTHOR]

Electrical transmission between neurons is largely mediated by gap junctions. These junctions allow the direct flow of electric current between neurons, and in mammals, they are mostly composed of the protein connexin36. Circuits of electrically coupled neurons are widespread in these animals. Plus, experimental and theoretical evidence supports the notion that, beyond synchronicity, these circuits are able to perform sophisticated operations such as lateral excitation and inhibition, noise reduction, as well as the ability to selectively respond upon coincident excitatory inputs. Although once considered stereotyped and unmodifiable, we now know that electrical synapses are subject to modulation and, by reconfiguring neural circuits, these modulations can alter relevant operations. The strength of electrical synapses depends on the gap junction resistance, as well as on its functional interaction with the electrophysiological properties of coupled neurons. In particular, voltage and ligand gated channels of the non-synaptic membrane critically determine the efficacy of transmission at these contacts. Consistently, modulatory actions on these channels have been shown to represent relevant mechanisms of plasticity of electrical synaptic transmission. Here, we review recent evidence on the regulation of electrical synapses of mammals, the underlying molecular mechanisms, and the possible ways in which they affect circuit function.

Fast-spiking (FS) cells in layer IV of the somatosensory cortex receive direct thalamocortical (TC) input and provide feed-forward inhibition onto layer IV excitatory cells. The level of synchronous firing of FS cells will affect the shape of this feed-forward output. Two factors that contribute to the synchrony are correlated TC input and electrical coupling between FS cells. Using a cell-pair model, we show that these two factors act synergistically to increase synchrony, and we examine the underlying mechanism. © 2006 Elsevier B.V. All rights reserved.

We investigated gap-junctional coupling of rods and cones in macaque retina. Cone voltage responses evoked by light absorption in neighboring rods were briefer and smaller than responses recorded in the rods themselves. Rod detection thresholds, calculated from noise and response amplitude histograms, closely matched the threshold for an ideal detector limited by quantal fluctuations in the stimulus. Surprisingly, cone thresholds were only approximately two times higher. Amplitude fluctuations in cones could be explained by a Poisson distribution of photoisomerizations within a pool of seven or more coupled rods. Neurobiotin coupling between rods and cones was consistent with our electrical recordings, with approximately six rods labeled per injected cone. The spatial distribution of tracer-coupled rods matched the light-evoked cone receptive field. The gap junction inhibitor carbenoxolone abolished both electrical and tracer coupling. Amplitude fluctuations in most rods were accounted for by the expected rate of light absorption in their outer segments. The fluctuations in some rods, however, were consistent with a summation pool of up to six rods. When single rods were injected with Neurobiotin, up to 10 rods were labeled. Rod-rod and rod-cone electrical coupling is expected to extend the range of scotopic vision by circumventing saturation at the rod to rod-bipolar cell synapse; however, because coupling also renders the rod synapse less effective at separating out photon signals from dark noise, coupling is expected to elevate the absolute threshold of dark-adapted observers.

During the last decades it became increasingly evident that electrical synapses are capable of activity-dependent plasticity. However, measuring the actual strength of electrical transmission remains difficult. Usually changes in coupling strength can only be inferred indirectly from measures such as the coupling coefficient and the coupling conductance. Because these are affected by both junctional and non-junctional conductance, plastic changes can potentially be due to both components. Furthermore, these techniques also require the blocking of chemical transmission, so that processes that involve crosstalk between chemical and electrical synapses will be suppressed. To directly examine the magnitude of errors that can occur, we use dual whole-cell current- and voltage-clamp recordings from the soma of the pair of easily accessible, electrically coupled Retzius cells in the leech to simultaneously determine coupling coefficients, coupling conductances and directly measured gap junctional currents. We present the first direct and comparative analysis of gap junction conductance using all three methods and analyze how each method would characterize the response of gap junctions to serotonin. The traditional coupling coefficients showed severe deficits in assessing the symmetry and strength of electrical synapses. These were reduced when coupling conductances were determined and were absent in the direct method. Additionally, both coupling coefficient and coupling conductance caused large and systematic errors in assessing the size and time course of the serotonin-induced changes of gap junctional currents. Most importantly, both measurements can easily be misinterpreted as implying long-term gap junctional plasticity, although the direct measurements confirm its absence. We thus show directly that coupling coefficients and coupling conductances can severely confound plastic changes in membrane and junctional conductance. Wherever possible, voltage clamp measurements should be chosen to accurately characterize the timing and strength of plasticity of electrical synapses. However, we also demonstrate that coupling coefficients can still yield a qualitatively correct picture when amended by independent measurements of the course of membrane resistance during the experiments.

Traditional bioelectronics, primarily comprised of nonliving synthetic materials, lack cellular behaviors such as adaptability and motility. This shortcoming results in mechanically invasive devices and nonnatural signal transduction across cells and tissues. Moreover, resolving heterocellular electrical communication in vivo is extremely limited due to the invasiveness of traditional interconnected electrical probes. In this paper, we present a cell-silicon hybrid that integrates native cellular behavior (e.g., gap junction formation and biosignal processing) with nongenetically enabled photosensitivity. This hybrid configuration allows interconnect-free cellular modulation with subcellular spatial resolution for bioelectric studies. Specifically, we hybridize cardiac myofibroblasts with silicon nanowires and use these engineered hybrids to synchronize the electrical activity of cardiomyocytes, studying heterocellular bioelectric coupling in vitro. Thereafter, we inject the engineered myofibroblasts into heart tissues and show their ability to seamlessly integrate into contractile tissues in vivo. Finally, we apply local photostimulation with high cell specificity to tackle a long-standing debate regarding the existence of myofibroblast-cardiomyocyte electrical coupling in vivo. [ABSTRACT FROM AUTHOR]