Central Electrode Research Articles

A Double‐Arch‐Structured Hybrid Triboelectric and Piezoelectric Nanogenerator Based on Polyvinylidene Fluoride/Graphene Oxide Composite Films

In this study, a methodology for fabricating double‐arch triboelectric and piezoelectric composite nanogenerators using polyvinylidene fluoride (PVDF) and graphene oxide (GO) is presented. Initially, nanofiber films comprising PVDF/GO are synthesized through electrostatic spinning. Subsequently, the PVDF/GO film is integrated with cotton fibers and a copper electrode to construct the triboelectric layer. In contrast, another portion of the PVDF/GO film, alongside a copper electrode, comprises the piezoelectric layer, with the central copper electrode acting as a common electrode. Finally, a double‐arch structure is established by employing polyethylene terephthalate film to facilitate synergistic operation between the triboelectric and piezoelectric layers. In the experimental results, it is indicated that the maximum open‐circuit voltage and short‐circuit current of the triboelectric layer of the double‐arch structure are 330 V and 36 μA, respectively, representing increases of 44% and 50% compared to those of the sandwich triboelectric structure. Additionally, the maximum open‐circuit voltage and short‐circuit current of the piezoelectric layer are 22 V and 4 μA, respectively, reflecting enhancements of 57% and 100% over those of conventional sandwich piezoelectric structures. The output power of the double‐arch composite nanogenerator is capable of lighting up 120 light‐emitting diodes. Thus, this composite nanogenerator shows great potential as an environmentally friendly energy source.

Sleep-spindles as a marker of attention and intelligence in dogs

The sleep spindle-generating thalamo-cortical circuitry supports attention capacity in awake humans and animals, but using sleep spindles to predict differences in attention has not been tried in either. Of the more commonly examined cognitive correlates of spindle occurrence and amplitude, post-sleep recall, and general intelligence, only post-sleep recall had been studied in dogs, rats and mice. Here, we examined a sample of companion dogs (N = 58) for whom polysomnographic recordings and several cognitive tests were performed on two occasions each, with a three-month break in-between. Five of the tests were used to extract a factor analogous to human g (general mental ability). A sixth test in the battery measured sustained attention. Both attention and g-factor scores were predicted by higher slow spindle occurrence and absolute sigma power detected in polysomnographic recordings over the central electrode. These effects persisted across measurement occasions. Higher intrinsic spindle frequency was, in turn, linked to lower g-factor scores but displayed no relationship with attention scores. The overlap in localization and direction for the effects of slow spindle density (spindles/minute) and sigma power supports that they tap into the same underlying cognition-relevant aspects of spindling. Given earlier large sample and meta-analysis validations of sigma power as a reliable predictor of cognitive performance in humans, we thus conclude that the currently handled method for quantifying spindle density in dogs indeed measures cognition-relevant spindle activity by virtue of its agreement with the sigma power alternative.

Cortical brain potentials in response to lower limb proprioceptive stimuli in young adults with probable developmental coordination disorder

BackgroundProprioceptive deficits have been shown to underlie motor problems in individuals with a probable developmental coordination disorder (pDCD). Behavioral studies have employed response times to passive limb movement to evaluate proprioceptive function in individuals with pDCD. However, the underlying neural mechanisms involved in the cortical processing of proprioceptive input and its corresponding motor response are unclear. To address this issue, this study aims to investigate neuropsychological and neurophysiological performances using event-related potentials (ERP) on proprioceptive-motor tasks in young adults with pDCD. MethodsFrom a total of 149 young adults screened using the Bruininks-Oseretsky Test of Motor Proficiency 2nd Edition Complete Form (BOT-2), 12 individuals with pDCD were identified (mean age ± SD: 20.50 ± 1.08 years) along with 12 age- and sex-matched controls (mean age ± SD: 20.75 ± 1.05 years). Participants placed their dominant foot on a passive ankle motion apparatus that plantarflexed the ankle at a constant velocity of 22°/s for a total of 75 trials in each proprioceptive condition. With vision occluded, participants had to press the trigger button held by the dominant hand when they sensed the passive motion of the ankle (voluntary response, VR), or purely receive the movement without a voluntary response (non-voluntary response, NVR). Behavioral performances [i.e., mean movement detection time (MDTmean), the standard deviation of the movement detection time (MDTSD)] and ERP indices (i.e., N1, P3 amplitude, and latency) related to ankle kinesthetic stimuli were obtained to determine the proprioceptive-motor function. ResultsThe results showed that young adults with pDCD exhibited longer MDTmean (p < 0.001) and MDTSD (p = 0.002) compared to their controls. Electrophysiological indices measured at frontal and central electrode sites, showed that young adults with pDCD exhibited significantly smaller N1 (p = 0.019) and P3 amplitudes (p = 0.032) during VR and NVR conditions. Notably, correlation analysis revealed a significant negative relationship between MDTmean and N1 (r = 0.62, p < 0.001) and P3 amplitudes (r = − 0.55, p = 0.005) in the VR condition in young adults with and without pDCD. ConclusionsThis study sheds light on the central brain mechanisms underlying proprioceptive-motor deficits in young adults with pDCD. The combined analysis of behavioral and ERP data suggests that longer MDTmean and larger MDTSD in young adults with pDCD are associated with weaker proprioceptive afferent inflow shown by decreased N1 amplitude to the frontal and parietal cortices. Such degraded proprioceptive signals are followed by reduced P3 amplitude, suggesting that young adults with pDCD allocate fewer neural resources to modulate motor processes with regard to proprioceptive stimuli. These findings contribute to a better understanding of the neurophysiological basis of proprioceptive-motor deficits in pDCD and may inform the development of targeted sensorimotor interventions.

Ion crystal size and structure in Paul traps.

This article presents a relationship between the size of an ion crystal in a Paul trap and the radio frequency potential applied on the central ring electrode. Using a simple and elegant derivation it has been shown that the distance of an ion in the crystal from the trap center is proportional to power of the applied radio frequency voltage. The validity of this power law has been demonstrated on ion crystals having up to 13 ions. A spring-mass model has been presented to predict structure of ion crystals in Paul traps operating in the Dehmelt regime. Structures are obtained by minimizing the total potential energy stored in an ion ensemble. The total potential energy is taken to be the sum of the electrostatic potential due to ion-ion interaction and the potential energy stored in the springs. Structures of crystals having up to 13 ions predicted by our model have been verified by comparing them with results obtained by direct numerical simulations.

What guides the judgment of learning: Memory or heuristics? An event-related potential study

Memory monitoring ability is essential for the effectiveness of learning processes. Judgment of Learning (JOL), a metacognitive judgment, is commonly used to measure this ability. An ongoing debate questions whether JOL is an outcome of an inferential or recollective experience, as suggested by different hypotheses regarding the underlying cognitive mechanisms of this judgment. To address this question through a neuroscientific perspective, we aimed to investigate the temporal dynamic of JOL adopting event-related potential (ERP) methodology. Seventy-two young adults participated in an episodic memory task involving word-pairs as stimuli. Their JOLs were obtained through categorical choices in a delayed condition. Additionally, their memory performance was tested in the recognition phase. ERP components were compared for different JOL levels, as well as for the hit responses in the recognition test according to their JOL levels. The analyses showed that JOL processes are observable within an early time window after stimulus presentation, as evidenced by elicitation of the P100, N100, P200, N200, and P300 components across all JOL levels. However, only the amplitude of the N100 varied among these levels. A negative ERP component with 330–500 ms latency was also evident for all JOL levels in the central and parietal electrodes, which did not differ in amplitude. The analyses of the recognition phase ERPs showed that the hit responses did not exhibit a significant difference in the familiarity-related mid-frontal old/new effect (FN400) amplitude; however, those with high level of JOL elicited recollection-related parietal old-new effect with a smaller amplitude. These findings support both hypotheses suggesting that JOL is influenced by heuristics and the retrievability of information.

Semantic Context Effects in Picture and Sound Naming: Evidence from Event-related Potentials and Pupillometric Data.

When a picture is repeatedly named in the context of semantically related pictures, (homogeneous context) responses are slower than when the picture is repeatedly named in the context of unrelated pictures (heterogeneous context). This semantic interference effect in blocked-cyclic naming plays an important role in devising theories of word production. Wöhner, Mädebach, and Jescheniak [2021; Wöhner, S., Mädebach, A., & Jescheniak, J. D. Naming pictures and sounds: Stimulus type affects semantic context effects. Journal of Experimental Psychology: Human Perception and Performance, 47, 716-730, 2021] have shown that the effect is substantially larger when participants name environmental sounds than when they name pictures. We investigated possible reasons for this difference, using EEG and pupillometry. The behavioral data replicated Wöhner and colleagues. ERPs were more positive in the homogeneous compared with the heterogeneous context over central electrode locations between 140-180 msec and 250-350 msec for picture naming and between 250 and 350 msec for sound naming, presumably reflecting semantic interference during semantic and lexical processing. The later component was of similar size for pictures and sounds. ERPs were more negative in the homogeneous compared with the heterogeneous context over frontal electrode locations between 400 and 600 msec only for sounds. The pupillometric data showed a stronger pupil dilation in the homogeneous compared with the heterogeneous context only for sounds. The amplitudes of the late ERP negativity and pupil dilation predicted naming latencies for sounds in the homogeneous context. The latency of the effects indicates that the difference in semantic interference between picture and sound naming arises at later, presumably postlexical processing stages closer to articulation. We suggest that the processing of the auditory stimuli interferes with phonological response preparation and self-monitoring, leading to enhanced semantic interference.

INVESTIGATION OF PLASMA VISCOSITY AND MAGNETIC FORCES IN COAXIAL PLASMA DISCHARGE DEVICE

This paper investigates the axial plasma current sheath, PCS viscosity force, and its correlation with other magnetic forces acting on it at three different radial positions (2.625, 3.625, and 4.125 cm) within the annular space between the coaxial electrodes system of plasma discharge device (12 kV-56 kA) with positive central electrode. The rate of change of PCS momentum was also investigated at these axial and radial positions. The discharge processes are carried out with an argon gas pressure of 0.8 Torr. Experimental results of azimuthal magnetic induction as a function of axial and radial positions and Navier Stokes equation were employed to compute exactly, the rate of change of PCS momentum, axial magnetic force, magnetic pressure gradient force, and viscosity force.

Design and first tests of the trapped electrons experiment T-REX.

Gyrotrons are essential for electron cyclotron resonance heating in fusion reactors, making efficient operation crucial for advancing fusion energy. Past experiments revealed instability issues due to trapped electrons in the magnetron injection gun (MIG) region, causing undesired currents and operational failures. To address this, tight manufacturing tolerances are required for the MIG geometry [Pagonakis etal., Phys. Plasmas 23, 023105 (2016)]. We present the initial findings of the trapped electrons experiment developed at the Swiss Plasma Center, designed to understand the physics of electron clouds in gyrotron MIGs. T-REX replicates MIG geometries, as well as their typical electric and magnetic fields, and it is supported by 2D particle-in-cell simulations with the FENNECS code [Le Bars etal., Phys. Plasmas 29, 082105 (2022); Le Bars, Ph.D. thesis, EPFL, Lausanne, 2023]. The setup includes two coaxial electrodes in a vacuum chamber atop a superconducting magnet, with a central electrode biased to negative DC voltages and an outer one at the ground, creating a radial electric field (1-2MV/m) and an axial magnetic field (B < 0.4T). This setup mimics Penning-Malmberg traps. We present the experimental device and first findings on current distribution and also a qualitative comparison with FENNECS simulations [Le Bars etal., Comput. Phys. Commun. 303, 109268 (2024)]. Planned diagnostics include optical emission spectroscopy, phosphor screen imaging, streak camera imaging, and potentially electric field distribution via the Stark effect. This research aims to enhance gyrotron performance and reliability in fusion energy systems.

Reliable measurement of auditory-driven gamma synchrony with a single EEG electrode: A simultaneous EEG-MEG study

ObjectiveAuditory-driven gamma synchrony (GS) is linked to the function of a specific cortical circuit based on a parvalbumin+ and pyramidal neuron loop. This circuit is impaired in neuropsychiatric conditions (i.e. schizophrenia, Alzheimer's disease, stroke etc.) and its relevance in clinical practice is increasingly being recognized. Auditory stimulation at a typical gamma frequency of 40 Hz can be applied as a ‘stress test’ of excitation/inhibition (E/I) of the entire cerebral cortex, to drive GS and record it with magnetoencephalography (MEG) or high-density electroencephalography (EEG). However, these two techniques are costly and not widely available. Therefore, we assessed whether a single EEG electrode is sufficient to provide an accurate estimate of the auditory-driven GS level of the entire cortical surface while expecting the highest correspondence in the auditory and somatosensory cortices. MethodsWe measured simultaneous EEG-MEG in 29 healthy subjects, utilizing 3 EEG electrodes (C4, F4, O2) and a full MEG setup. Recordings were performed during binaural exposure to auditory gamma stimulation and during silence. We compared GS measurement of each of the three EEG electrodes separately against full MEG mapping. Time-resolved phase locking value (PLVt) was computed between EEG signals and cortex reconstructed MEG signals. ResultsDuring auditory stimulation, but not at rest, EEG captures a significant amount of GS, especially from both auditory cortices and motor-premotor regions. This was especially true for frontal (C4) and central electrodes (F4). Discussion and ConclusionsWhile hd-EEG and MEG are necessary for accurate spatial mapping of GS at rest and during auditory stimulation, a single EEG channel is sufficient to detect the global level of GS. These results have great translational potential for mapping GS in standard clinical settings.

Physical exercise on cortical brain activity in patients with mild cognitive impairment: A meta-analysis.

Physical exercise is recognized as a potential strategy to mitigate the cognitive decline associated with mild cognitive impairment (MCI). This systematic review aims to examine the specific effects of physical exercise on cortical brain activity in patients with MCI, an area that has not been thoroughly explored. We conducted a search across 9 electronic databases for randomized controlled trials assessing the impact of physical exercise on the cortical activity of patients with MCI. The search covered the period from database inception to September 2023. Literature screening, data extraction, and quality assessments were carried out by 2 independent researchers. Meta-analyses were conducted using RevMan 5.3, and publication bias was evaluated using STATA 17.0. This study primarily assessed P300 latency and amplitude, alongside cognitive evaluations using the mini-mental state examination and Montreal Cognitive Assessment. Six high-quality randomized controlled trials, involving a total of 360 participants, were included. Compared to the control group, significant enhancements were observed in the amplitude of central midline electrode (mean difference [MD] = 1.64 [95% confidence interval [CI], 0.92-2.36]; P < .00001), frontal midline electrode (MD = 2.70 [95% CI, 2.02-3.38]; P < .00001), and parietal midline electrode (MD = 2.42 [95% CI, 0.44-4.41]; P = .02). Latency periods of the central midline electrode (MD = -32.40 [95% CI, -40.27 to -24.54]; P < .00001), frontal midline electrode (MD = -12.57 [95% CI, -30.83 to 5.69]; P = .18), and parietal midline electrode (MD = -12.57 [95% CI, -30.83 to 5.69]; P = .81) were also notably influenced. Moreover, overarching cognitive functions as measured by mini-mental state examination (MD = 1.02 [95% CI, 0.61-1.43]; P < .00001) and Montreal Cognitive Assessment (MD = 1.39 [95% CI, 0.67-2.12]; P = .0002) exhibited marked improvement. This meta-analysis suggests that physical exercise can augment the P300 amplitude, reduce the P300 latency period, and, overall, enhance cognitive functionality in individuals with MCI.

Imbalance in positive and negative acceleration ratio of alpha oscillation in patients with complex regional pain syndrome

ObjectivesTo elucidate the functional characteristics of the brain in the presence of chronic pain using electroencephalography (EEG), with a focus on the dynamics of neural excitation and inhibition. MethodsResting-state EEG was performed in: 17 patients with complex regional pain syndrome (CRPS) who exhibited chronic pain higher than 20 on the visual analogue scale (VAS), 6 patients with reduced CRPS symptoms and chronic pain less than 20 on VAS, and healthy age-matched controls. For the analysis, 50 s of electroencephalogram (EEG) signals were extracted from EEG recordings during wakefulness and rest with eyes closed. The envelope of the alpha frequency band was calculated by examining the positive and negative accelerations of the envelope oscillation, ratio of positive (Ap) to negative (An) accelerations (Ap-An ratio), and mean amplitude of the envelope. Comparisons were made between patients and controls, and correlations between these EEG measures and the subjective pain VAS were evaluated.Significant differences in the value of Ap, An and Ap-An ratio were observed at temporal and central electrodes between patients with pain symptoms and controls. Those with reduced CRPS symptoms exhibited a distinct Ap-An ratio at the majority of electrodes when compared with those exhibiting chronic pain. ConclusionsDistinct patterns in alpha wave envelope dynamics, reflecting excitatory and inhibitory activities, were associated with chronic pain in patients with CRPS. The pain-relieved state of CRPS suggested that a new balance of activities was established. This relationship indicated a potential association between altered alpha oscillation characteristics and the subjective experience of pain. SignificanceThis study introduces a novel method for analyzing alpha oscillation envelopes, providing new insights into the neural pathophysiology of chronic pain in CRPS patients. This approach has the potential to enhance our understanding of the alterations in brain function that occur under chronic pain conditions.

Electrochemical impedance analysis of the charge transfer mechanism on Li4Ti5O12 surface in the presence or absence of the solid/electrolyte interface film

A novel three-electrode type cell is developed for highly reliable electrochemical impedance spectroscopy (EIS). A pair of Li4Ti5O12 (LTO) electrodes are placed at both end of the cell, and a lithium counter electrode is inserted between them to assemble a three-electrode-type LTO half-cell. The half-cell is initially discharged to either 0.3 or 1.4 V to prepare the pair of LTO electrodes with or without a solid/electrolyte interface (SEI) film, respectively. The half-cells are reassembled to LTO symmetric cells by removing the central Li electrode without damaging the LTO electrodes. EIS measurements of the symmetric cell indicate impedances associated with charge transfer (RCT) and the SEI film (RSEI) in distinctly different frequency ranges. The temperature dependences of RCT and RSEI are analyzed to clearly understand the influence of the SEI film on the charge transfer mechanism and to explicitly support the common understanding that lithium ions are desolvated at the film/electrolyte interface or inside the film through a different consideration than the conventional one.

The OrbiTOF mass analyzer: Time-of-flight analysis via an orbitrap quadro-logarithmic field with periodic drift focusing

Thermo Scientific™ Orbitrap™ analyzers represent a prominent class of high-resolution mass analyzer commonly used in life sciences, and for interrogation of complex samples. Injected ions, trapped within a quadro-logarithmic field, orbit a central electrode and oscillate up and down the axis. A new class of multi-reflection time-of-flight mass analyzer has been developed based on the Orbitrap field structure plus an additional series of periodic lenses wrapped around the central axis to constrain beam dispersion. The axial and angular velocity of the injected ions was balanced so that with each axial oscillation, the ions passed through the next lens in the series, to form a tightly folded 25-m long, 3-dimensional ion path, ending with ions striking a detector surface.Performance was interrogated via experiment and simulation. 70k resolving power was observed within the relatively compact analyzer, albeit at cost to transmission. A larger design with an integrated extraction trap and greater flight energy is discussed.

Memorization-Based Training and Testing Paradigm for Robust Vocal Identity Recognition in Expressive Speech Using Event-Related Potentials Analysis.

Recognizing familiar speakers from vocal streams is a fundamental aspect of human verbal communication. However, it remains unclear how listeners can still discern the speaker's identity in expressive speech. This study develops a memorization-based individual speaker identity recognition approach and an accompanying electroencephalogram (EEG) data analysis pipeline, which monitors how listeners recognize familiar speakers and tell unfamiliar ones apart. EEG data captures online cognitive processes during new versus old speaker distinction based on voice, offering a real-time measure of brain activity, overcoming limits of reaction times and accuracy measurements. The paradigm comprises three steps: listeners establish associations between three voices and their names (training); listeners indicate the name corresponding to a voice from three candidates (checking); listeners distinguish between three old and three new speaker voices in a two-alternative forced-choice task (testing). The speech prosody in testing was either confident or doubtful. EEG data were collected using a 64-channel EEG system, followed by preprocessing and imported into RStudio for ERP and statistical analysis and MATLAB for brain topography. Results showed an enlarged late positive component (LPC) was elicited in the old-talker compared to the new-talker condition in the 400-850 ms window in the Pz and other wider range of electrodes in both prosodies. Yet, the old/new effect was robust in central and posterior electrodes for doubtful prosody perception, whereas the anterior, central, and posterior electrodes are for confident prosody condition. This study proposes that this experiment design can serve as a reference for investigating speaker-specific cue-binding effects in various scenarios (e.g., anaphoric expression) and pathologies in patients like phonagnosia.

Пьезоэлектрический дисковый актюатор кручения с дискретно-спиральными электродами

A mathematical model of a disk (ring) torsion actuator with curvilinear interdigital electrodes – «villi» of a spiral form, which are characterized by a constant value of the orientation angle of an arbitrary section of the villus to the circumferential direction of the disk, has been developed. Bases of electrode-villi interacting with each other through local areas of piezoelectric layer are connected with periodic alternation to central or peripheral concentric circular base electrodes, to outputs of which control voltages are connected. As a result of numerical modeling of the «twisting bimorph» graphs of the dependence of the twist angle and the blocking torque on the ratio of the inner and outer radii and the values of the control voltage at the outputs of the base electrodes of the annular two-layer actuator with symmetrical (relative to the radial line) directions of the spiral orientations of the electrode-villi and, as a result, the spiral polarization lines of the piezoelectric layers working for tension/compression.

Assessing the effectiveness of high-definition transcranial direct current stimulation for treating obsessive-compulsive disorder: Results from a randomized, double-blind, controlled trial

ObjectiveCharacterized by its disabling nature, obsessive compulsive disorder (OCD) affects individuals profoundly, with nearly 40% of patients showing resistance to initial treatment methods. Despite being safe and easily accessible, transcranial direct current stimulation (tDCS) lacks extensive substantiation supporting its efficacy in treating OCD. The objective of this study was to evaluate how cathodal high-definition transcranial direct current stimulation (HD-tDCS) applied to the right orbitofrontal cortex affected patients with OCD in terms of efficacy. Method47 patients with OCD were enrolled. They were randomly allocated to active or sham stimulation groups, and underwent HD-tDCS stimulation treatment for 2 weeks. The central electrode located in the right orbitofrontal cortex region was cathodic. The severity of the patients' obsessive-compulsive symptoms, depression and anxiety were assessed before and after treatment. ResultOut of the total, 44 patients concluded the treatment, comprising 23 participants from the active stimulation group and 21 from the sham stimulation group. Notably, substantial reductions in symptoms related to OCD, depression, and anxiety were exhibited in both groups. With a response rate of 26.1% in the active stimulation group and 23.8% in the sham stimulation group, there was no significant difference in efficacy observed. Furthermore, the reduction in depression and anxiety symptoms at the conclusion of the treatment was not notably superior in the active stimulation group. ConclusionThis study provided evidence for the acceptability and safety of HD-tDCS. Nevertheless, the study did not reveal notable clinical effectiveness of tDCS in addressing moderate to severe OCD in comparison to the sham stimulation group.

Neural basis of lower-limb visual feedback therapy: an EEG study in healthy subjects

BackgroundVideo-feedback observational therapy (VOT) is an intensive rehabilitation technique based on movement repetition and visualization that has shown benefits for motor rehabilitation of the upper and lower limbs. Despite an increase in recent literature on the neurophysiological effects of VOT in the upper limb, there is little knowledge about the cortical effects of visual feedback therapies when applied to the lower limbs. The aim of our study was to better understand the neurophysiological effects of VOT. Thus, we identified and compared the EEG biomarkers of healthy subjects undergoing lower limb VOT during three tasks: passive observation, observation and motor imagery, observation and motor execution.MethodsWe recruited 38 healthy volunteers and monitored their EEG activity while they performed a right ankle dorsiflexion task in the VOT. Three graded motor tasks associated with action observation were tested: action observation alone (O), motor imagery with action observation (OI), and motor execution synchronized with action observation (OM). The alpha and beta event-related desynchronization (ERD) and event-related synchronization (or beta rebound, ERS) rhythms were used as biomarkers of cortical activation and compared between conditions with a permutation test. Changes in connectivity during the task were computed with phase locking value (PLV).ResultsDuring the task, in the alpha band, the ERD was comparable between O and OI activities across the precentral, central and parietal electrodes. OM involved the same regions but had greater ERD over the central electrodes. In the beta band, there was a gradation of ERD intensity in O, OI and OM over central electrodes. After the task, the ERS changes were weak during the O task but were strong during the OI and OM (Cz) tasks, with no differences between OI and OM.ConclusionAlpha band ERD results demonstrated the recruitment of mirror neurons during lower limb VOT due to visual feedback. Beta band ERD reflects strong recruitment of the sensorimotor cortex evoked by motor imagery and action execution. These results also emphasize the need for an active motor task, either motor imagery or motor execution task during VOT, to elicit a post-task ERS, which is absent during passive observation.Trial Registration NCT05743647

Plasma pressure profiles in a sheared-flow-stabilized Z-pinch

We report the plasma pressure reached inside the central plasma column of a sheared-flow-stabilized Z-pinch using Thomson scattering measurements. Building on previously reported experimental results and the analysis methods established for the high temperature and moderate density plasmas generated on the FuZE device, we show evidence of a central plasma region with higher electron temperature and density, which is consistent with a pinch behavior. Elevated electron temperatures up to 2.25 ± 0.8 keV and densities up to (4.9±0.2)×1017 cm−3 are observed to temporally coincide with the fusion neutron production from the plasma. Reconstructed plasma pressure profiles highlight the presence of a several millimeter-wide column with elevated pressure whose location varies shot-to-shot. The plasma pressure rises as neutron production from the deuterium plasma increases, reaching a peak value of 2.6 kBar. This peak value is consistent with a radially force-balanced pinch equilibrium model based on the measured ∼320 kA pinch current. Complete datasets were obtained at two axial locations, 10 and 20 cm axial position from the tip of the central electrode, which corroborate the estimated neutron source axial lengths.

Entropy in Electroencephalographic Signals Modulates with Force Magnitude During Grasping – A Preliminary Report

The ability to hold objects relies on neural processes underlying grip force control during grasping. Brain activity lateralized to contralateral hemisphere averaged over trials is associated with grip force applied on an object. However, the involvement of neural variability within-trial during grip force control remains unclear. We examined dependence of neural variability over frontal, central, and parietal regions of interest (ROI) on grip force magnitude using noninvasive electroencephalography (EEG). We utilized our existing EEG dataset comprised of healthy young adults performing an isometric force control task, cued to exert 5, 10, or 15% of their maximum voluntary contraction (MVC) across trials and received visual feedback of their grip force. We quantified variability in EEG signal via sample entropy (sequence-dependent) and standard deviation (sequence-independent measure) over ROI. We found lateralized modulation in EEG sample entropy with force magnitude over central electrodes but not over frontal or parietal electrodes. However, modulation was not observed for standard deviation in the EEG activity. These findings highlight lateralized and spatially constrained modulation in sequence-dependent, but not sequence-independent component of EEG variability. We contextualize these findings in applications requiring finer precision (e.g., prosthesis), and propose directions for future studies investigating role of neural entropy in behavior.

An innovative electrolytic cation exchange reactor system for cleaner generation of hydrogen gas using ocean water

The study presents a novel integrated three-compartment electrochemical continuous electrodeionization reactor that was constructed in a laboratory environment. In order to extract large amounts of carbon dioxide from naturally occurring oceanwater in the form of bicarbonate and carbonate, it develops a innovative electrolytic cation exchange process. At the same time, it produces hydrogen gas for possible hydrocarbon synthesis. The study employs the Box-Behnken experimental design approach implemented through the Design Expert software to investigate and optimize the performance of electrochemical hydrogen extraction from Ocean water from an integrated reactor. The integrated electrochemical continuous-type electrodeionization reactor comprises two cation-permeable membranes that operate as boundaries between three compartments: a central compartment and electrode compartments that house the cathode and anode, each of which may reverse polarity. These membranes are made of gel polystyrene cross-linked with divinylbenzene, which has acidic properties that allow cation transport while inhibiting anions. The integrated reactor's electrode chambers are enclosed in plexiglass end plates and contain distinct Plexiglass electrode compartments. These compartments have mesh and solid steel anode and cathode electrodes, with an electrode active area of 176.71 cm2. The influence of various factors, such as voltage and electrolyte amount, on the production of hydrogen synthesis is examined. The study results demonstrate a maximum hydrogen production rate of 2.2 mg/min and a hydrogen production efficiency of 7.82%. The lab testing was carried out using experimental equipment to determine viability. The tests included 35-min runs that measured hydrogen generation under various parameters, such as applied voltage, electrolyte concentration, and pH levels. The ocean salt solutions of 0.5M, 1M, and 2M were initially prepared and evaluated for hydrogen generation. Each concentration is assessed at a voltage range of 4–15V, with matching solution pH values ranging from 2 to 7. Optimization studies were conducted to enhance the hydrogen production rate. The results indicate that hydrogen production rises proportionally with applied voltage and electrolyte concentration but falls with pH growth. Within the Design Expert software, the statistical methods for response surface analysis and optimization are utilized accordingly.