Electric Current Research Articles

Synchronization evaluation of memristive photosensitive neurons in multi-neuronal systems

At the forefront of brain-computer interface (BCI) technology exploration, the synchronization phenomenon in neural networks demonstrates significant potential for application. This paper focuses on the memory characteristics and nonlinear dynamic behavior of memristors, an emerging electronic component. By innovatively integrating memristors, phototubes, and FitzHugh-Nagumo (FHN) circuits, we construct a memristive photosensitive neuron (MPN) model, aiming to explore its unique role in neural network synchronization. Utilizing the memristors' inherent memory capabilities and nonlinear properties, the MPN model mimics the dynamic behavior of biological neurons. Experiments show that synchronization is highly sensitive to the memristor's initial values, revealing intricate synchronization regulation mechanisms. Furthermore, we find that chaotic electrical currents, as environmental disturbances, have dual effects—either promoting or inhibiting MPN network synchronization—depending on specific parametric conditions. To simulate a realistic biological neural network and achieve efficient coupling among multiple MPN units, this paper adopts a Hopfield network structure. The results indicate that this structure significantly enhances the synchronization stability of the system, reduces sensitivity to initial conditions, and mitigates the adverse effects of chaotic currents. This research not only enhances our understanding of neural network synchronization but also provides novel theoretical support and technical pathways for the development of BCI technology, indicating broad application prospects in neuroscience, rehabilitative medicine, and other fields.

Virus inactivation using an electrically conducting virus filter in biopharmaceutical manufacturing process

Biopharmaceutical manufacturing processes using mammalian cells or plasma carry the risk of viral contamination. To mitigate these risks, it is essential to ensure viral clearance during the downstream process. Virus-retentive filters are used for size-based virus filtration, offering robust viral removal of more than 99.99%. However, virus breakthroughs have also been reported during virus filtration under certain conditions. In addition, these virus-retentive filters are disposable to ensure the safety of bioproducts, leading to significant costs and environmental concerns. In this study, innovative electrically conducting virus filters were fabricated using free-standing carbon veils (CV) and used to achieve additional virus inactivation after filtration. The viruses were captured in a CV-assisted virus filter, which was electrically heated using direct current to inactivate the viruses. This electrically conducting virus filter can inactivate viruses and can be reused up to five times. These results demonstrate that electrical conduction through electrical conducting damaged the phage capsid and eliminated the RNA genome, leading to bacteriophage inactivation. Moreover, it was confirmed that the electrically conducting virus filter could be reused up to five times without any changes to its physical or chemical structure. This study contributes to the reduction of process costs and environmental impacts by enabling the reuse of virus filters and enhancing the safety of the virus filtration process by preventing undesired virus breakthroughs.

Nonparametric Statistics on Magnetic Properties at the Footpoints of Erupting Magnetic Flux Ropes

It is under debate whether the magnetic field in the solar atmosphere carries neutralized electric currents, in particular, whether a magnetic flux rope (MFR), which is considered the core structure of coronal mass ejections, carries neutralized electric currents. Recently Wang et al. (2023) studied magnetic flux and electric current measured at the footpoints of 28 eruptive MFRs from 2010 to 2015. Because of the small sample size, no rigorous statistical analysis has been done. Here, we include nine more events from 2016 to 2023 and perform a series of nonparametric statistical tests at a significance level of 5%. The tests confirm that there exist no significant differences in magnetic properties between conjugated footpoints of the same MFR, which justifies the method of identifying the MFR footpoints through coronal dimming. The tests demonstrate that there exist no significant differences between MFRs with preeruption dimming and those with only posteruption dimming. However, there is a medium level of association between MFRs carrying substantial net current and those producing preeruption dimming, which can be understood by the Lorentz self-force of the current channel. The tests also suggest that in estimating the magnetic twist of MFRs, it is necessary to take into account the spatially inhomogeneous distribution of electric current density and magnetic field.

Abstract P388: Electrical Stimulation of the Porcine Carotid Sinus Nerve Reliably Decreases Blood Pressure and Heart Rate

Introduction: Neuromodulation of the baroafferent pathway via direct carotid sinus nerve (CSN) stimulation is recognized as a potential therapeutic modality for treating uncontrolled hypertension. Although proof of concept has been demonstrated acutely in humans, there are many questions that remain in both acute and chronic applications. A translational non-companion large animal model is vital for safe development of this modality. Here we present data on the effects of CSN and baroafferent stimulation in farm pigs. Hypothesis: We hypothesized that an effective CSN-bioelectode interface in the pig would demonstrate significant and reproducible reductions in blood pressure in tandem with pulse rate (PR). Methods: Acute CSN stimulation was investigated in 9 anesthetized Yorkshire pigs. Following general anesthesia, CSNs were exposed and an application-specific electrode was placed. A fixed current paradigm was employed at constant 100Hz and 100µs pulse width. Following contact mapping to identify the baroafferent neurointerface, electrical current was escalated to establish dose-response curves. The primary outcome was systolic blood pressure (SBP) and secondary outcomes were diastolic pressure (DBP) and PR. Data were analyzed in Matlab to extract the baseline BP and PR, during and following stimulation. Statistical calculations used a one-sample Wilcoxon signed rank test. Explanted electrodes with surrounding tissue were evaluated using micro-computed tomography (μCT) and histologically. Results: Six of 9 animals were responders (n=7, 2 sides were stimulated in one animal), CSN stimulation caused average (mean±SD, p<0.001) decreases in SBP (6.8±7.2mmHg) and DBP (3.9±3.7mmHg), which tracked closely with decreases in PR (6.2±5.7bpm). Average maximum decreases were: SBP, 9.3±9.9mmHg; DBP, 7.7±6.4mmHg; and PR, 9.7±8.3bpm. Upon stimulation withdrawal, there was near-immediate recovery of both BP and HR. μCT and histological analysis of tissue samples demonstrated inter-animal anatomic heterogeneity. Conclusions: CSN stimulation causes reproducible reduction in BP synchronous with PR drops followed by near immediate recovery of both with stimulation withdrawal. Variations in animal response may be due to anatomical variation in CSN anatomy that can be overcome with further anatomical study. Pigs provide a robust large-animal model for investigating CSN stimulation, offering a platform to better understand baroafferent stimulation as treatment for uncontrolled hypertension.

Sonoelectrochemical degradation of aspirin in aquatic medium using ozone and peroxymonosulfate activated with FeS2 nanoparticles

The catalytic performance of nano-FeS2 in the sonoelectrochemical activation of peroxymonosulfate (PMS) and ozone to remove aspirin (ASP) was studied for the first time. The crystal structure and Fe bonds in the catalyst were confirmed through XRD and FTIR analysis. Within 30 min, ASP (TOC) was removed by 99.2 % (81.6 %) and 98.6 % (77.4 %) in nano-FeS2/PMS and nano-FeS2/O3 sonoelectrochemical systems, respectively. Water anions, especiallyHCO3− (almost 50 %), had an inhibitory effect on ASP removal. The probes confirmed that SO4•−and HO• were the key to ASP degradation in nano-FeS2/PMS and nano-FeS2/O3 systems, respectively. The effective activation of oxidants due to the ideal distribution of Fe2+ by catalyst was the main mechanism of ASP removal, in which electric current (EC) and ultrasound (US) played a crucial role through the recycling of Fe ions, dissolution and cleaning of the catalyst. LC-MS analysis identified thirteen byproducts in the ASP degradation pathways. The energy consumption of the proposed sonoelectrochemical systems was lower than previous similar systems. This study presented economic and sustainable hybrid systems for pharmaceutical wastewater remediation.

Pre-anoxic electro-stimulation enhanced simultaneous nitrification–denitrification in single-stage electrolysis-integrated sequencing batch biofilm reactor

Simultaneous nitrification–denitrification (SND) is a promising nitrogen removal process. However, total nitrogen (TN) removal is limited due to unsatisfactory denitrification. This study demonstrated that short-time (1 h) pre-anoxic electro-stimulation significantly enhanced SND efficiency in the aerobic phase by promoting the proliferation of mixotrophic and heterotrophic denitrifiers. SND and TN removal efficiencies at the optimal electric current (EC) (0.02 A) were 85.6 % and 93.9 %, which were 39.1 % and 17.2 % higher than control. Microbial community analysis indicated that the abundance of mixotrophic and heterotrophic denitrifiers significantly increased. H2 generated in the electro-stimulation process induced the proliferation of mixotrophic denitrifiers. The weak EC (0.02 A) promoted the activity and growth of heterotrophic denitrifiers by accelerating electron transfer. They concurrently mediated heterotrophic denitrification to enhance SND efficiency. PICRUSt2 analysis revealed that the abundance of denitrifying genes dramatically surged. This study provides new insights into applying electrolysis to achieve advanced SND while minimizing electricity consumption.

Non-Contact Eddy Current Conductivity Measurements as an Effective Tool for Evaluating Aluminum Alloys in Aircraft

ABSTRACT Aluminum alloys (AAs) are pivotal materials in modern aircraft due to their superior mechanical properties and low weight. The structural integrity of these alloys, crucial for aircraft safety, heavily depends on heat treatment processes that alter their mechanical characteristics. Nondestructive evaluation (NDE) techniques, such as eddy current (EC) conductivity measurements, play a vital role in assessing these alloys throughout their lifecycle. EC methods enable the measurement of electrical conductivity, a structure-sensitive parameter that correlates with mechanical properties affected by heat treatments and operational stresses. This paper reviews the application of EC conductivity measurements in the aerospace industry, focusing on their role in assessing AA structural integrity. It discusses how EC methods can penetrate non-conductive coatings, crucial for in-service measurements without surface removal. Recent developments include a novel small-size EC probe and signal processing algorithms aimed at enhancing sensitivity to conductivity changes through dielectric coatings, up to 0.5 mm thick, commonly found in aircraft structures. Key findings include analyses of specific electrical conductivity (SEC) changes in AAs due to heat treatment deviations and long-term operational stresses, crucial for predicting residual life and maintaining safety standards. Case studies on aircraft wing skins and helicopter rotor blades demonstrate the practical application of EC conductivity meters in identifying critical damage zones. The methodology proves effective in evaluating localized degradation based on SEC distributions, thereby enhancing maintenance efficiency and aircraft safety. Overall, this research underscores the significance of EC conductivity measurements in advancing NDE practices for AAs in aircraft applications. The methodologies and findings presented aim to improve safety, durability assessment, and maintenance efficiency in the aerospace industry.

O51 EXPLORING GENETIC BASIS OF RESISTANT HYPERTENSION IN EUROPEAN AND AFRICAN POPULATIONS

Background: Approximately 15% of hypertensive (HTN) patients experience resistant hypertension (RHTN) despite the use of ≥ 3 antihypertensive agents (diuretic and blockers of calcium channels and the renin-angiotensin system) at maximum tolerated doses. Intriguingly, genetic variation and alterations in gene content may contribute to RHTN developing. Aim: To comprehend the genetic determinants of RHTN across diverse ethnicities, this study has compared the gene content and presence of single nucleotide variants (SNVs) in RHTN versus controlled-HTN and normotensive participants within European (EU) and South African (SA) populations. Methods: Blood-isolated DNA was collected from 6 participants from EU and 15 from SA. Patients were categorized into 3 groups: RHTN (SA; n=5 and EU; n=6), controlled-HTN (n=5), and normotensive (n=5). DNA was used for Whole Exome Sequencing (WES) analysis. Library preparation and exome capture were done using the MGIEasy Universal DNA library prep and exome capture v5 probe set. Mapping was done using GATK, and the variant calling and annotation were performed using with the SIFT tool and R software. Results: PCA analysis and minimum spanning network showed significant genetic diversity between EU and SA populations. WES identified 16 common genes, with 207 and 220 genes associated to RHTN in EU and SA, respectively. These genes were involved in cardiac electrical conduction (K+/Ca++ channels) and lipid storage (HDL deficiency). In addition, SNV within pharmacogenes in SA (CYP2D6, CYP3A5, APOE) and EU (ADD1) cohorts alongside genes linked to disease susceptibility (RyR1 and PPP1CA) were also identified. RyR1 and PPP1CA are both implicated in HTN development through their roles in calcium signaling and vascular smooth muscle cell function. Noteworthy, two SNVs, rs121918006 and rs61732908, within RyR1 were previously linked to HTN. Conclusions: The large genetic differences observed between EU and SA subjects highlight the diverse genetic landscape surrounding RHTN. Notably, specific genes and their related SNV that associated to cardiac calcium channels and lipid storage could show potential targets for personalized therapeutic intervention. Scientific Session 15: Exploring Novel Therapeutic Approaches to Kidney Disease

A Data-constrained Analysis for Joule Heating as a Solar Active Region Atmosphere Heating Mechanism. I. Sunspot Umbral Light Bridge

Understanding the mechanisms underlying the heating of the solar atmosphere is a fundamental problem in solar physics. The lower atmosphere of the Sun (i.e., photosphere and chromosphere) is composed of weakly ionized plasma. This results in anisotropic dissipation of electric currents by Coulomb and Cowling resistivities. Joule heating due to dissipation of currents perpendicular to the magnetic field by Cowling resistivity has been demonstrated to be the main mechanism for the heating of a sunspot umbral light bridge located in NOAA AR 12002 on 2014 March 13. Here, we focus on the same target region and demonstrate the importance of further constraining our Joule heating model using observational data in addition to magnetic field, namely plasma temperature calculated from the inversion of spectroscopic data obtained from the Interferometric BI-dimensional Spectrometer instrument of the ground-based Dunn Solar Telescope. As a parameter in our analysis, temperature is demonstrated to have the highest sensitivity after magnetic field. We show that the heating of the light bridge is a highly dynamic event that necessitates utilization of 3D spatially resolved observational data for temperature rather than a 1D temperature stratification based on theoretical/semiempirical solar atmosphere models. Our improved data-constrained analysis using spatially resolved temperatures shows that the entire light bridge is heated by the proposed mechanism, and yields heating rate values that are consistent with our previous study.

Atmospheric heating and magnetism driven by 22Ne distillation in isolated white dwarfs

The origin of atmospheric heating in the cool, magnetic white dwarf GD 356 remains unsolved nearly 40 years after its discovery. This once idiosyncratic star with Teff ≈ 7500 K, yet Balmer lines in Zeeman-split emission is now part of a growing class of white dwarfs exhibiting similar features, and which are tightly clustered in the HR diagram suggesting an intrinsic power source. This paper proposes that convective motions associated with an internal dynamo can power electric currents along magnetic field lines that heat the atmosphere via Ohmic dissipation. Such currents would require a dynamo driven by core 22Ne distillation, and would further corroborate magnetic field generation in white dwarfs by this process. The model predicts that the heating will be highest near the magnetic poles, and virtually absent toward the equator, in agreement with observations. This picture is also consistent with the absence of X-ray or extreme ultraviolet emission, because the resistivity would decrease by several orders of magnitude at the typical coronal temperatures. The proposed model suggests that i) DAHe stars are mergers with enhanced 22Ne that enables distillation and may result in significant cooling delays; and ii) any mergers that distill neon will generate magnetism and chromospheres. The predicted chromospheric emission is consistent with the two known massive DQe white dwarfs.

Influence of sinusoidal forcing on the master FitzHugh–Nagumo neuron model and global dynamics of a unidirectionally coupled two-neuron system

In this paper, we investigate a seven-parameter, five-dimensional dynamical system, specifically a unidirectional coupling of two FitzHugh–Nagumo neuron models, with one neuron being sinusoidally driven. This master–slave configuration features neuron N1 as the master, subjected to an external sinusoidal electrical current, and neuron N2 as the slave, interacting with N1 through an electrical force. We report numerical results for three distinct scenarios where N1 operates in (i) periodic, (ii) quasiperiodic, and (iii) chaotic regimes. The primary objective is to explore how the dynamics of the master neuron N1 influence the coupled system’s behavior. To achieve this, we generated cross sections of the seven-dimensional parameter space, known as parameter planes. Our findings reveal that in the periodic regime of N1, the coupled system exhibits period-adding sequences of Arnold tongue-like structures in the parameter planes. Furthermore, regions of multistability can also be identified in these parameter planes of the coupled system. In the quasiperiodic regime, regions of periodic motion are absent, with only regions of quasiperiodic and chaotic dynamics present. In the chaotic regime of N1, the parameter planes display regions of chaos, hyperchaos, and transient hyperchaos.

A reduced ideal MHD system for nonlinear magnetic field turbulence in plasmas with approximate flux surfaces

This paper studies the nonlinear evolution of magnetic field turbulence in proximity of steady ideal Magnetohydrodynamics (MHD) configurations characterized by a small electric current, a small plasma flow, and approximate flux surfaces, a physical setting that is relevant for plasma confinement in stellarators. The aim is to gather insight on magnetic field dynamics, to elucidate accessibility and stability of three-dimensional MHD equilibria, as well as to formulate practical methods to compute them. Starting from the ideal MHD equations, a reduced dynamical system of two coupled nonlinear partial differential equations for the flux function and the angle variable associated with the Clebsch representation of the magnetic field is obtained. It is shown that under suitable boundary and gauge conditions such reduced system preserves magnetic energy, magnetic helicity, and total magnetic flux. The noncanonical Hamiltonian structure of the reduced system is identified, and used to show the nonlinear stability of steady solutions against perturbations involving only one Clebsch potential. The Hamiltonian structure is also applied to construct a dissipative dynamical system through the method of double brackets. This dissipative system enables the computation of MHD equilibria by minimizing energy until a critical point of the Hamiltonian is reached. Finally, an iterative scheme based on the alternate solution of the two steady equations in the reduced system is proposed as a further method to compute MHD equilibria. A theorem is proven which states that the iterative scheme converges to a nontrivial MHD equilbrium as long as solutions exist at each step of the iteration.

Batch Electrocoagulation Process for the Removal of High Colloidal Clay from Open-Cast Coal Mine Water Using Al and Fe Electrodes

Open-cast coal mining operations can produce water with high amounts of total suspended solids (TSS). We tested the use of electrocoagulation for the removal of colloidal clay from mine water. Monopolar batch electrocoagulation was performed at the laboratory scale using Al and Fe electrodes and varying the DC current (0.5, 1, and 2 A) and contact time (15, 30, and 45 min). Aluminum electrode electrocoagulation with a current of 2 A and a contact time of 15 min had the greatest TSS removal efficiency (99%), with concentrations decreasing from 5,400 to 23 mg/L. The greatest removal (98 and 99%, respectively) was obtained using an Al electrode with an electric current of 0.5 and 1 A, with 30 min of contact time. With an Fe electrode, the greatest efficiency was achieved with a current of 2 A and a contact time of 30 min. The TSS removal efficiency reached 98% while the concentration dropped to 66 mg/L, followed by 89% and 95% for the 0.5 A-45 min and 1 A-15 min variations, respectively.

Properties of sunspot light bridges on a geometric height scale

Context. Investigating light bridges (LBs) helps us comprehend key aspects of sunspots. However, few studies have analyzed the properties of LBs in terms of the geometric height, which is a more realistic perspective given the corrugation of the solar atmosphere. Aims. We aim to shed light on LBs by studying the variation in their physical properties with geometric height. Methods. We used the SICON code to infer the physical quantities in terms of the optical depth and the Wilson depression values of three LBs hosted by a sunspot observed with Hinode/SP in the Fe I 630 nm pair lines. We also used SIR inversions to cross-check the height variation of the field inclination in the LBs. In both output sets, we performed linear interpolation to convert the physical parameters from optical depth into a geometric height scale in each pixel. Results. Depending on their general appearance, we classified each LB as filamentary, grainy, or umbral. They appear as ridges that reach different maximum heights, with the umbral LB being the deepest. While the filamentary LB hosts a plasma inflow from the penumbra, the results for the grainy LB are compatible with an injection of hot plasma through convective cells of reduced field strength. Only a few positions reveal hints suggesting a cusp-like magnetic canopy. Moreover, strong gradients in the magnetic field strength and inclination usually exhibit enhanced electric currents, with the filamentary LB having remarkably strong currents that appear to be related to chromospheric events. Conclusions. The height stratification in filamentary and grainy LBs differ, indicating diverse mechanisms at work. Our results are in general incompatible with a magnetic canopy scenario, and further analysis is needed to confirm whether it exists along the entire LB or only at specific locations. Furthermore, this work assesses the usefulness of the SICON code when determining the height stratification of solar structures.

Possible mechanism of action potential propagation mediated by static electric field: A novel assumption of understanding nerve interaction and ephaptic coupling

The generation and propagation of physical signals in living biosystems are continuous issues. Traditional Hodgkin-Huxley model based on ionic current conduction could not explain the fast transmission of action potential in myelinated axons and factors influencing action potential velocity. We propose that the ion flow induced by Nav channel generates near field quasi-static electric field at extracellular space, termed as an ephaptic field which is able to excite nearby passive axons. Our simulation indicates that the static electric field produced by sodium ion channels in one node of Ranvier is improbable to stimulate the ion channels in the adjacent neighboring node. However, the ion channel ring in one node of Ranvier could induce the shift of membrane potential (0.01 mV) on the node at nearby axons (100 μm) in a bundle of axon synchronously, suggesting zig-zag propagation of action potential. Together with the superposition effect of ephaptic feedback field generated by the synchronized movement of adjacent parallel axons stimulate the adjacent node of the original axon, strengthen the action potential to travel in a zig-zag pattern. Our model also provides an explanation for the rapid velocity of action potential propagation reported in experimental studies.

Manipulation of Magnonic Activity by Electric Currents in Ferromagnetic Nanocylinders

Electric currents passing through ferromagnets can impact the magnetization dynamics via the so-called spin-transfer torque (STT) effect. In this paper, we present a theoretical study on the current influence on magnonic activity, a recently reported spin wave (SW) chiral effect in ferromagnetic nanotubes. By micromagnetic simulations, we show that an electric current can cause a significant change in the rotatory power of the SW modes propagating in a longitudinally magnetized nanotube. This result is well explained by using the Fresnel model in optics assuming a SW circular birefringence. An analytical method is developed to solve the first-order mode, yielding perfect agreements with the numerical results. Our results provide a new approach to manipulate the SW propagating properties in ferromagnetic nanocylinders.

Optimizing arsenic removal from groundwater using continuous flow electrocoagulation with iron and aluminum electrodes: An experimental and modeling approach

Arsenic contamination in groundwater is a global issue. This study examines arsenic removal using continuous flow electrocoagulation with iron and aluminum electrodes. Various parameters, such as electrode material, number, and applied voltage, were tested. Arsenic removal efficiencies ranged from 52 % to 89 % with aluminum electrodes and 46 % to 96 % with iron electrodes, depending on conditions. Surface pretreatment of electrodes significantly enhanced performance. Iron electrodes provided a faster and more cost-effective solution compared to aluminum. Statistical methods, including Pearson's correlation and Gradient Boosting Machine (GBM) modeling, were used to optimize operational parameters like current density, coagulant dose, pH, and conductivity. The GBM model achieved high predictive accuracy (R2 > 0.97), capturing complex relationships. Experiment duration was the most critical factor, contributing 70.2 % to arsenic removal efficiency, with a strong correlation (r = 0.75). Coagulant dose was also crucial, followed by current density and voltage. Cost analysis combined with GBM modeling optimized cost-efficiency for achieving arsenic levels below 10 μg/L. This research offers valuable insights for optimizing electrocoagulation processes, demonstrating the potential of machine learning in enhancing water treatment technologies.

Laying of the main cables of the SCB with AC electric current

Laying of the main cables of the SCB with AC electric current

Atmospheric modulation of apparent electrical conductivity in a metal−organic framework

Combining high surface area and efficient charge transport, electrically conductive metal−organic frameworks (MOFs) find wide applications in energy storage, sensing, and electrocatalysis. Reliable characterization of electrical conductivity, the key metric for assessing this class of materials, remains challenging due to its high sensitivity to the atmosphere. Herein, through electrical characterization of an exemplary MOF, Cd2(TTFTB) (TTFTB4− = tetrathiafulvalene tetrabenzoate), under various controlled atmospheres, we show that adsorption of water in humid air or N2 improves the apparent room-temperature electrical conductivity by one to two orders of magnitude compared to the values observed in dry atmospheres. This observation in conjunction with spectroscopic characterization, structural analysis, and band structure calculations indicates significant contribution of water-mediated proton conductivity and/or proton-electron coupling to the apparent electrical conductivity. Thus, controlling and reporting atmospheres in electrical conductivity measurements of MOFs is critical to improve their reproducibility and to gain insights into electrical conduction mechanisms.

Long-distance electron transport in multicellular freshwater cable bacteria.

Filamentous multicellular cable bacteria perform centimeter-scale electron transport in a process that couples oxidation of an electron donor (sulfide) in deeper sediment to the reduction of an electron acceptor (oxygen or nitrate) near the surface. While this electric metabolism is prevalent in both marine and freshwater sediments, detailed electronic measurements of the conductivity previously focused on the marine cable bacteria (Candidatus Electrothrix), rather than freshwater cable bacteria, which form a separate genus (Candidatus Electronema) and contribute essential geochemical roles in freshwater sediments. Here, we characterize the electron transport characteristics of Ca. Electronema cable bacteria from Southern California freshwater sediments. Current-voltage measurements of intact cable filaments bridging interdigitated electrodes confirmed their persistent conductivity under a controlled atmosphere and the variable sensitivity of this conduction to air exposure. Electrostatic and conductive atomic force microscopies mapped out the characteristics of the cell envelope's nanofiber network, implicating it as the conductive pathway in a manner consistent with previous findings in marine cable bacteria. Four-probe measurements of microelectrodes addressing intact cables demonstrated nanoampere currents up to 200 μm lengths at modest driving voltages, allowing us to quantify the nanofiber conductivity at 0.1 S/cm for freshwater cable bacteria filaments under our measurement conditions. Such a high conductivity can support the remarkable sulfide-to-oxygen electrical currents mediated by cable bacteria in sediments. These measurements expand the knowledgebase of long-distance electron transport to the freshwater niche while shedding light on the underlying conductive network of cable bacteria.