Screw Electrodes Research Articles

Electrical synapses interconnecting axons in the optic nerve head–a novel model of optic nerve function

AbstractPurposeAxons in the optic nerve are arranged in bundles and conducting action potential with resistance related to their membrane. Here, we aim to characterize the function of newly identified gap junctions coupling optic nerve axons with each other’s.MethodsProximal and distal rat optic nerve stumps were processed for immunostainings, electron microscopy (EM), RT‐PCR and western blots (WB). Additional 20 animals were deeply anesthetized, and stainless‐steel screw electrodes were drilled in skulls in standard locations to record fVEPs. Recordings were performed in untouched animals, after retrobulbar injection of saline (negative control) or meclofenamic acid solution (gap junctions’ blocker). Human paraffin cross‐sections of eyeballs for immunostainings were obtained from the Human Eye Biobank for Research, University of Toronto, Canada.ResultsImmunostaining of rat and human samples revealed presence of Cx45 and 36 in axonal membranes, colocalizing with β3‐tubulin, but not with GFAP. In WB, Cx36 content in optic nerve was approximately halved when compared with retina (0.58 ± 0.005 ‐ proximal stump; 0.44 ± 0.02 ‐ distal stump), Cx45 showed higher levels (0.68 ± 0.0003 ‐ proximal stump; 0.9 ± 0.07 ‐ distal stump). Additionally, we detected transcript of Cx45 and Cx36 in RT‐PCR analysis of optic nerve homogenates. In immunogold‐EM of optic nerve sections, we found electric synapses (formed mostly by Cx45) that are directly coupling neighboring axons. In fVEPs, blocking of gap junctions’ with meclofenamic acid resulted in prolongation of the latency of P1 wave up to 140% after 5 min from retrobulbar injection of this blocker (p < 0.001) and 170% after 30 min (p < 0.001).ConclusionsOptic nerve axons do not form absolutely independent conductive channels. They are directly coupled by gap junctions formed in majority by neuronal Cx45. Coupling of axons allows to reduce axonal membrane resistance and accelerates transduction of visual signal.

Characterization of Epileptic Spiking Associated With Brain Amyloidosis in APP/PS1 Mice.

Epileptic activity without visible convulsions is common in Alzheimer's disease (AD) and may contribute adversely to the disease progress and symptoms. Transgenic mice with amyloid plaque pathology also display epileptic seizures, but those are too infrequent to assess the effect of anti-epileptic treatments. Besides spontaneous seizures, these mice also display frequent epileptic spiking in epidural EEG recordings, and these have provided a means to test potential drug treatment to AD-related epilepsy. However, the origin of EEG spikes in transgenic AD model mice has remained elusive, which makes it difficult to relate electrophysiology with underlying pathology at the cellular and molecular level. Using multiple cortical and subcortical electrodes in freely moving APP/PS1 transgenic mice and their wild-type littermates, we identified several types of epileptic spikes among over 15 800 spikes visible with cortical screw electrodes based on their source localization. Cortical spikes associated with muscle twitches, cortico-hippocampal spikes, and spindle and fast-spindle associated spikes were present equally often in both APP/PS1 and wild-type mice, whereas pure cortical spikes were slightly more common in APP/PS1 mice. In contrast, spike-wave discharges, cortico-hippocampal spikes with after hyperpolarization and giant spikes were seen almost exclusively in APP/PS1 mice but only in a subset of them. Interestingly, different subtypes of spikes responded differently to anti-epileptic drugs ethosuximide and levetiracetam. From the translational point most relevant may be the giant spikes generated in the hippocampus that reached an amplitude up to ± 5 mV in the hippocampal channel. As in AD patients, they occurred exclusively during sleep. Further, we could demonstrate that a high number of giant spikes in APP/PS1 mice predicts seizures. These data show that by only adding a pair of hippocampal deep electrodes and EMG to routine cortical epidural screw electrodes and by taking into account underlying cortical oscillations, one can drastically refine the analysis of cortical spike data. This new approach provides a powerful tool to preclinical testing of potential new treatment options for AD related epilepsy.

Genetic absence epilepsy: Effective connectivity from piriform cortex to mediodorsal thalamus

ObjectiveThe objective of the study was to quantify effective connectivity from the piriform cortex to mediodorsal thalamus, in Genetic Absence Epilepsy Rats from Strasbourg (GAERS). MethodsLocal field potentials (LFPs) were recorded using microelectrode arrays implanted in the mediodorsal thalamus and piriform cortex, in three urethane anesthetized GAERS and three control rats. Screw electrodes were placed in the primary motor cortex to identify epileptiform discharges. We used transfer entropy to measure effective connectivity from piriform cortex to mediodorsal thalamus prior to and during generalized epileptiform discharges. ResultsWe observed increased theta band effective connectivity from piriform cortex to mediodorsal thalamus, prior to and during epileptiform discharges in GAERS compared with controls. Increased effective connectivity was also observed in beta and gamma bands from the piriform cortex to mediodorsal thalamus, but only during epileptiform discharges. ConclusionsThis preliminary study suggests that increased effective theta connectivity from the piriform cortex to the mediodorsal thalamus may be a feature of the ‘epileptic network’ associated with genetic absence epilepsy. Our findings indicate an underlying predisposition of this direct pathway to propagate epileptiform discharges in genetic absence epilepsy.

Harmonization of the pipeline for seizure detection to phenotype post-traumatic epilepsy in a preclinical multicenter study on post-traumatic epileptogenesis

RationaleThe Epilepsy Bioinformatics Study for Antiepileptogenic Therapy (EpiBioS4Rx) Centre without walls is an NIH funded multicenter consortium. One of EpiBioS4Rx projects is a preclinical post-traumatic epileptogenesis biomarker study that involves three study sites: The University of Eastern Finland, Monash University (Melbourne) and the University of California Los Angeles. Our objective is to create a platform for evaluating biomarkers and testing new antiepileptogenic treatments for post-traumatic epilepsy (PTE) using the lateral fluid percussion injury (FPI) model in rats. As only 30–50% of rats with severe lateral FPI develop PTE by 6 months post-injury, prolonged video-EEG monitoring is crucial to identify animals with PTE. Our objective is to harmonize the surgical and data collection procedures, equipment, and data analysis for chronic EEG recording in order to phenotype PTE in this rat model across the three study sites. MethodsTraumatic brain injury (TBI) was induced using lateral FPI in adult male Sprague-Dawley rats aged 11–12 weeks. Animals were divided into two cohorts: a) the long-term video-EEG follow-up cohort (Specific Aim 1), which was implanted with EEG electrodes within 24 h after the injury; and b) the magnetic resonance imaging (MRI) follow-up cohort (Specific Aim 2), at 5 months after lateral FPI. Four cortical epidural screw electrodes (2 ipsilateral, 2 contralateral) and three intracerebral bipolar electrodes were implanted (septal CA1 and the dentate gyrus, layers II and VI of the perilesional cortex both anterior and posterior to the injury site). During the 7th post-TBI month, animals underwent 4 weeks of continuous video-EEG recordings to diagnose of PTE. ResultsAll centers harmonized the induction of TBI and surgical procedures for the implantation of EEG recordings, utilizing 4 or more EEG recording channels to cover areas ipsilateral and contralateral to the brain injury, perilesional cortex and the hippocampus and dentate gyrus. Ground and reference screw electrodes were implanted. At all sites the minimum sampling rate was 512 Hz, utilizing a finite impulse response (FIR) and impedance below 10 KΩ through the entire recording. As part of the quality control criteria we avoided electrical noise, and monitoring changes in impedance over time and the appearance of noise on the recordings. To reduce electrical noise, we regularly checked the integrity of the cables, stability of the EEG recording cap and the appropriate connection of the electrodes with the cables. Following the pipeline presented in this article and after applying the quality control criteria to our EEG recordings all of the sites were successful to phenotype seizure in chronic EEG recordings of animals after TBI. DiscussionDespite differences in video-EEG acquisition equipment used, the three centers were able to consistently phenotype seizures in the lateral fluid-percussion model applying the pipeline presented here. The harmonization of methodology will help to improve the rigor of preclinical research, improving reproducibility of pre-clinical research in the search of biomarkers and therapies to prevent antiepileptogenesis.

Harmonization of pipeline for detection of HFOs in a rat model of post-traumatic epilepsy in preclinical multicenter study on post-traumatic epileptogenesis

Studies of chronic epilepsy show pathological high frequency oscillations (HFOs) are associated with brain areas capable of generating epileptic seizures. Only a few of these studies have focused on HFOs during the development of epilepsy, but results suggest pathological HFOs could be a biomarker of epileptogenesis. The Epilepsy Bioinformatics Study for Antiepileptogenic Therapy” (EpiBioS4Rx) is a multi-center project designed to identify biomarkers of epileptogenesis after a traumatic brain injury (TBI) and evaluate treatments that could modify or prevent the development of post-traumatic epilepsy. One goal of the EpiBioS4Rx project is to assess whether HFOs could be a biomarker of post-traumatic epileptogenesis. The current study describes the work towards this goal, including the development of common surgical procedures and EEG protocols, an interim analysis of the EEG for HFOs, and identifying issues that need to be addressed for a robust biomarker analysis. At three participating sites – University of Eastern Finland (UEF), Monash University in Melbourne (Melbourne) and University of California, Los Angeles (UCLA) – TBI was induced in adult male Sprague-Dawley rats by lateral fluid-percussion injury. After injury and in sham-operated controls, rats were implanted with screw and microwire electrodes positioned in neocortex and hippocampus to record EEG. A separate group of rats had serial magnetic resonance imaging after injury and then implanted with electrodes at 6 months. Recordings 28 days post-injury were available from UEF and UCLA, but not Melbourne due to technical issues with their EEG files. Analysis of recordings from 4 rats – UEF and UCLA each had one TBI and one sham-operated control – showed EEG contained evidence of HFOs. Computer-automated algorithms detected a total of 1,819 putative HFOs and of these only 40 events (2%) were detected by all three sites. Manual review of all events verified 130 events as HFO and the remainder as false positives. Review of the 40 events detected by all three sites was associated with 88% agreement. This initial report from the EpiBioS4Rx Consortium demonstrates the standardization of EEG electrode placements, recording protocol and long-term EEG monitoring, and differences in detection algorithm HFO results between sites. Additional work on detection strategy, detection algorithm performance, and training in HFO review will be performed to establish a robust, preclinical evaluation of HFOs as a biomarker of post-traumatic epileptogenesis.

Semi-invasive and non-invasive recording of visual evoked potentials in mice.

Visual evoked potentials (VEPs) are used to assess visual function in preclinical models of neurodegenerative diseases. VEP recording with epidural screw electrodes is a common method to study visual function in rodents, despite being an invasive procedure that can damage the tissue under the skull. The present study was performed to test a semi-invasive (epicranial) and a non-invasive (epidermal) VEP recording technique, comparing them with the classic epidural acquisition method. Flash VEPs were recorded from C57BL/6 mice on three separate days within 2weeks. Waveforms, latencies and amplitudes of the components were compared between the three different methods, utilizing coefficient of repeatability, coefficient of variation and intersession standard deviation to evaluate reproducibility. While epidural electrodes succeeded in recording two negative peaks (N1 and N2), epicranial and epidermal electrodes recorded a single peak (N1). Statistical indexes showed a comparable reproducibility between the three techniques, with a greater stability of N1 latency recorded through epicranial electrodes. Moreover, N1 amplitudes recorded with the new less-invasive methods were more reproducible compared to the invasive gold-standard technique. These results demonstrate the reliability of semi- and non-invasive VEP recordings, which can be useful to evaluate murine models of neurological diseases.

The Effect of Nitrendipine and Levetiracetam in Pentylenetetrazole Kindled Rats

We aimed to investigate the efficacy of L-type voltage gated calcium channel blocker nitrendipine and levetiracetam in pentylenetetrazole (PTZ) kindled male rats. In order to establish kindling model, 35 mg/kg PTZ injected intraperitoneally (i.p.) to male wistar albino rats three days a week. Then, screw electrodes were placed in the skulls of the kindled rats. During the experiments, EEG activities and seizure behaviors of kindled rats were recorded. The kindled rats were divided into control (n=6), PTZ (n=6), nitrendipine (2.5 mg/kg (n=6), 5 mg/kg (n=6), 10 mg/kg (n=6)) and levetiracetam (10 mg/kg (n=6), 20 mg/kg (n=6), 40 mg/kg (n=6)) groups. Nitrendipine (5 mg/kg) and levetiracetam (20 mg/kg) were suppressed the spike frequency and the seizure score effectively (p 0.05). The co-administration of nitrendipine and levetiracetam was not more effective than administration of nitrendipine or levetiracetam separately (p>0.05).

A novel simplistic fabrication technique for cranial epidural electrodes for chronic recording and stimulation in rats

Background:The demand for neuromodulatory and recording tools has resulted in a surge of publications describing techniques for fabricating devices and accessories in-house suitable for neurological recordings. However, many of these fabrication protocols use equipment which are not common to biological laboratories, thus limiting researchers to the use of commercial alternatives.New method:We have developed a simple yet robust implantable stimulating surface electrode which can be fabricated in all wet-bench laboratories.Results:Female Sprague-Dawley rats received epidural implantation of the electrodes over the fore and hind limb areas of their motor cortex. Stimulation of the motor cortex successfully evoked fore- and hind limb motor outputs. The device was also able to record surface potentials of the motor cortex following epidural stimulation of the spinal cord.Comparisons with existing methods:For stimulation of the motor cortex, often stiff stainless or copper wires are roughly tucked underneath the skull, with little accuracy of localization. While, commercially available devices utilize burr holes and screw electrodes. Our new electrode design provides us stereotaxic accuracy that was not previously available.Conclusion:We developed a chronic implantable electrode capable of being fabricated in all wet-labs, are robust, versatile and electrically sensitive enough for long-term chronic use. The simple and versatile electrode design provides scientific, economical and ethical benefits.

The "sacrificial electrode" : A safe option for the management of pacemaker infections in pacemaker-dependent patients

As the number of cardiac implantable electronic devices (CIEDs) increases, so does the need to revise such systems. Pacemaker-dependent patients with a CIED infection are particulary challenging for the attending physician. Here, the CIED cannot simply be removed without replacement. Gold standard therapy is asufficient, prolonged antibiosis, the complete removal of the CIED, and the installation of atemporary pacemaker system - usually by means of atransvenous probe or epimyocardial probe via thoracotomy. The disadvantages of these therapies are the insecure positioning of the unfixed transvenous or the invasiveness of the epimyocardial probes. Alternatively, we have since 2015 established aconcept with the so-called "sacrificial" electrode. For this purpose - during the explantation of the infected CIED - aconventional, transvenous screw electrode is anchored via the subclavian vein in the right ventricle and is then connected cutaneously to an aggregate. If the anti-infective therapy is successful, anew CIED is implanted whenever possible over the contralateral side in the usual way. Stimulation via the sacrificial electrode can be stopped and the probe removed. This method is technically easy to perform and offers great advantages: no dislocation of the probe and maintained patient mobility.

An analysis of intelligent LED emergency lamp with voltage and resistance activated sensor

LED as illumination lamps has become popular because of its efficiency to save energy, especially electricity. This lamp can be operated as normal lamp connected to AC power line but if the failure of power line electricity occurs, the lamp is still on for hours depends on battery capacity. This lamp circuits have voltage and resistance sensor in the end of circuit connected to threaded (screw) electrode of the lamp. This paper analyzes the principle and performance of the circuit, especially to voltage and resistance threshold activation, and the other factor that can cause success or failure operation. The analysis concludes that the voltage from power line installation can activate the lamp to bright up and to charge its battery at once. When the supply of power source is failure, it triggers the circuit to keep the lamp on with battery operated, by term and condition applied that the connection to line power installation established. It is caused of resistance sensor that detected no resistance value in loop circuit connection. This lamp will be able to operate correctly in single line load circuit, and only one lamp as line load, no other resistive or inductive load.

Long-term evaluation and feasibility study of the insulated screw electrode for ECoG recording

BackgroundA screw-shaped electrode can offer a compromise between signal quality and invasiveness. However, the standard screw electrode can be vulnerable to electrical noise while directly contact with the skull or skin, and the feasibility and stability for chronic implantation in primate have not been fully evaluated. New MethodWe designed a novel screw electrocorticogram (ECoG) electrode composed of three parts: recording electrode, insulator, and nut. The recording electrode was made of titanium with high biocompatibility and high electrical conductivity. Zirconia is used for insulator and nut to prevent electrical noise. ResultIn computer simulations, the screw ECoG with insulator showed a significantly higher performance in signal acquisition compared to the condition without insulator. In a non-human primate, using screw ECoG, clear visual-evoked potential (VEP) waveforms were obtained, VEP components were reliably maintained, and the electrode’s impedance was stable during the whole evaluation period. Moreover, it showed higher SNR and wider frequency band compared to the electroencephalogram (EEG). We also observed the screw ECoG has a higher sensitivity that captures different responses on various stimuli than the EEG. ComparisonThe screw ECoG showed reliable electrical characteristic and biocompatibility for three months, that shows great promise for chronic implants. These results contrasted with previous reports that general screw electrode was only applicable for acute applications. ConclusionThe suggested electrode can offer whole-brain monitoring with high signal quality and minimal invasiveness. The screw ECoG can be used to provide more in-depth understanding, not only relationship between functional networks and cognitive behavior, but also pathomechanisms in brain diseases.

Algorithm for automatic detection of spontaneous seizures in rats with post-traumatic epilepsy

BackgroundLabor intensive electroencephalogram (EEG) analysis is a major bottleneck to identifying anti-epileptogenic treatments in experimental models of post-traumatic epilepsy. We aimed to develop an algorithm for automated seizure detection in experimental post-traumatic epilepsy. New methodContinuous (24/7) 1-month-long video-EEG monitoring with three epidural screw electrodes was started 154 d after lateral fluid-percussion induced traumatic brain injury (TBI; n = 97) or sham-injury (n = 29) in adult male Sprague–Dawley rats. First, an experienced researcher screened a total of 90,720 h of digitized recordings on a computer screen to annotate the occurrence of spontaneous seizures. The same files were then analyzed using an algorithm in Spike2 (ver.9), which searching for temporally linked power peaks (14–42 Hz) in all three EEG channels, and then positive events were marked as a probable seizures. Finally, an experienced researcher confirmed all seizure candidates visually on the computer screen. ResultsVisual analysis identified 197 seizures in 29 rats. Automatic detection identified 4346 seizure candidates in 109 rats, of which 202 in the same 29 rats were true positives, resulting in a false positive rate of 0.046/h or 1.10/d. The algorithm demonstrated 5% specificity and 100% sensitivity. The algorithm analyzed 1-month 3-channel EEG in 7 cohorts in 2 h, whereas analysis by an experienced technician took ∼500 h. Comparison with Existing MethodsThe algorithm had 100% sensitivity. It performed slightly better and was substantially faster than investigator-performed visual analysis. ConclusionsWe present a novel seizure detection algorithm for automated detection of seizures in a rat model of post-traumatic epilepsy.

Visual evoked potentials can be reliably recorded using noninvasive epidermal electrodes in the anesthetized rat.

Visual evoked potentials (VEPs) are a powerful tool to evaluate nervous conduction along the visual pathways, both in humans and in animal models. Traditionally, epidural screw electrodes are used to record VEPs in preclinical research. Here we tested the feasibility in the preclinical setting of the same noninvasive technique used for clinical VEP acquisition, by using epidermal cup electrodes with no surgical procedures. Monocular flash VEPs were recorded bilaterally under sevoflurane anesthesia once a week for 6weeks in 14 dark Agouti rats, 7 with implanted epidural screws and 7 with epidermal 6mm Ø Ag/AgCl cups. VEP traces obtained with the two techniques were morphologically comparable. There were no significant differences in latency of the main visual component between screw-recorded VEPs (sVEPs) and cup-recorded VEPs (cVEPs). Amplitude values with epidermal cups were significantly lower than those with epidural screws. Both techniques provided latencies and amplitudes which were stable over time. Furthermore, with regard to latency both methods ensured highly repeatable measurements over time, with epidermal cups even providing slightly better results. On the other hand, considering amplitudes, cVEPs and sVEPs provided fairly acceptable repeatability. Epidermal cup electrodes can provide comparable results to those obtained with the "gold standard" epidural screws, while representing a simpler and less invasive technique to test nervous conduction along the visual pathways in the preclinical setting.

Effects of low and high doses of acetylsalicylic acid on penicillin-induced epileptiform activity.

The most common headache associated with epilepsy occurs after seizure activity and is called a postictal headache. Therefore, the objective of this study was to investigate the effects of low and high doses acetylsalicylic acid (aspirin) on a penicillin-induced experimental epilepsy model. Adult male Wistar rats (n = 28, weighing 220 ± 40 g) were used in the experiments. The rats were divided into four groups as Control, Penicillin, Aspirin 150 mg/kg, Aspirin 500 mg/kg. Seizure activity was triggered by an intracortical injection of penicillin G potassium (500 IU/2.5 μl) into the sensory motor cortex. An electrocorticogram was recorded by using conductive screw electrodes. Aspirin at the doses of 500 mg/kg and 150 mg/kg was given intraperitoneally (ip) 30 min after penicillin administration. Anticonvulsant activity appeared at the 30th and 40th min after an intracortically administered injection of penicillin in the groups given aspirin doses of 500 mg/kg (ip) and 150 mg/kg (ip) respectively. The amplitude of epileptiform activity at both doses of aspirin decreased but the difference was not statistically significant. The results of the present study suggest that low and high doses of aspirin may decrease epileptiform activity in penicillin-induced epilepsy. Aspirin might be suggested for headache associated with epilepsy.

Ozone generation characteristic by different divided outer electrodes of screw electrode ozonizer

ABSTRACTMethyl bromide is used as the disinfectant of soil and agricultural chemicals. However, methyl bromide has been prohibited from using except for indispensable uses. Therefore, ozone has bee...

Evoked potential and EEG study of the neurotoxicity of hydramethylnon in rats

The objective of the study was to assess the neurotoxicity, using electrodiagnostic tests, of hydramethylnon (Amdro, AC 217,300), an insecticide marketed for the treatment of red imported fire ants, cockroaches, and other insects. Animals were male Fisher 344 albino rats and Long-Evans hooded rats. Brainstem auditory, visual, and somatosensory evoked potentials (BAER, VEP, SEP) and electroencephalograms (EEG) were recorded from implanted screw electrodes before and at multiple time points through day 10 after a single oral dose of hydramethylnon (at 50% or 75% of the LD50) plus vehicle, or vehicle alone. No evidence of nervous system toxicity was detected with either BAER, VEP, or SEP recordings. Spectral analysis of EEGs recorded over 7days demonstrated a time-limited increase in power at low frequencies and decrease at high frequencies, reflecting a sedative effect. A dose-dependent weight loss was observed. Single-exposure poisonings with AC 217,300 can be expected to produce anorexia and CNS depression, but not lethality.

Morphological Evolution of Lithium Electrode in Lithium-Based Cells: Investigated By Synchrotron X-Ray Phase Contrast Tomography

Lithium (Li) metal, due to its high theoretical specific capacity (3860 mA h/g), low density (0.59 g/cm3) and the lowest negative electrochemical potential (-3.04 V vs. the standard hydrogen electrode), is widely considered as the most promising candidate for the next generation energy storage systems such as lithium-sulfur and lithium-air batteries. In addition, it has been currently used as a standard counter electrode for the evolution of new cathode or anode materials in half-cells. Unfortunately, the commercialization of Li metal as a negative electrode has not been succeeded due to the intrinsically uncontrolled growth of Lithium micro-Structures (LmSs, eg., dendrites, fibers) since the early investigation in 1970s. Although various characterization techniques such as optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and magnetic resonance imaging (MRI) have been employed to characterize the morphological changes of Li electrodes, our understanding towards the evolution of Li during operational cycling has not greatly improved owing to these inherently limited analytical tools. The challenge of a detailed nondestructive characterization way and a comprehensive analysis of correlation between the evolution of Li electrodes and the battery electrochemical performance still remains. In the present demonstration, the powerful characterization tool, synchrotron X-ray phase contrast tomography imaging technique will be employed to characterize the evolution of Li electrodes during cycling. To this end, we have designed and fabricated a tomography cell (tomo-cell) for the three-dimensional nondestructive investigation, as shown in Fig. 1, along with a schematic illustration of the beamline set-up. Fig. 1. a) Photograph of the fabricated proof-of-concept cell. b) Corresponding schematic representation of the cell consisting of a polyamide-imide housing (brown), two screw electrodes and retaining screws each on top (light grey), two sealing rings (yellow), a porous separator (white) sandwiched between two electrodes (blue and green). c) Schematic representation of the experimental setup of the tomography station at the BAMline at BESSY II, Helmholtz-Zentrum Berlin, Germany. This figure has been adapted from ACS Energy Lett., 2017, 2, pp 94–104, with permission by the American Chemical Society. Selected results of our previous investigations using this tomo-cell about the evolution of Li electrodes in half-cells (lithium-silicon, lithium-sulfur and lithium-lithium cobalt oxide) and symmetrical cells (Li-Li) will be briefly demonstrated. The morphological evolution of Li electrodes based on these measurements will also be summarized. These unprecedented findings, which were not accessible from conventional microscopic characterizations and electrochemical measurements, fundamentally deepen our understanding of the evolution mechanism of Li electrodes during battery cycling. The insights obtained could open up the way toward design principles and opportunities to accelerate the commercialization of Li metal. Figure 1

Thermal Release Transfer Printing for Stretchable Conformal Bioelectronics.

Soft neural electrode arrays that are mechanically matched between neural tissues and electrodes offer valuable opportunities for the development of disease diagnose and brain computer interface systems. Here, a thermal release transfer printing method for fabrication of stretchable bioelectronics, such as soft neural electrode arrays, is presented. Due to the large, switchable and irreversible change in adhesion strength of thermal release tape, a low‐cost, easy‐to‐operate, and temperature‐controlled transfer printing process can be achieved. The mechanism of this method is analyzed by experiments and fracture‐mechanics models. Using the thermal release transfer printing method, a stretchable neural electrode array is fabricated by a sacrificial‐layer‐free process. The ability of the as‐fabricated electrode array to conform different curvilinear surfaces is confirmed by experimental and theoretical studies. High‐quality electrocorticography signals of anesthetized rat are collected with the as‐fabricated electrode array, which proves good conformal interface between the electrodes and dura mater. The application of the as‐fabricated electrode array on detecting the steady‐state visual evoked potentials research is also demonstrated by in vivo experiments and the results are compared with those detected by stainless‐steel screw electrodes.

Novel electrode structure in a DBD reactor applied to the degradation of phenol in aqueous solution

Phenol degradation experimental results are presented in a similar wastewater aqueous solution using a non-thermal plasma reactor in a coaxial dielectric barrier discharge. The novelty of the work is that one of the electrodes of the reactor has the shape of a hollow screw which shows an enhanced efficiency compared with a traditional smooth structure. The experimentation was carried out with gas mixtures of 90% Ar–10% O2, 80% Ar–20% O2 and 0% Ar–100% O2. After one hour of treatment the removal efficiency was 76%, 92%, and 97%, respectively, assessed with a gas chromatographic mass spectrometry technique. For both reactors used, the ozone concentration was measured. The screw electrode required less energy, for all gas mixtures, than the smooth electrode, to maintain the same ozone concentration. On the other hand, it was also observed that in both electrodes the electrical conductivity of the solution changed slightly from ∼0.0115 S m−1 up to ∼0.0430 S m−1 after one hour of treatment. The advantages of using the hollow screw electrode structure compared with the smooth electrode were: (1) lower typical power consumption, (2) the generation of a uniform plasma throughout the reactor benefiting the phenol degradation, (3) a relatively lower temperature of the aqueous solution during the process, and (4) the plasma generation length is larger.

Interaction between urethane and cannabinoid CB1 receptor agonist and antagonist in penicillin-induced epileptiform activity.

Previous experimental studies have shown that various anesthetics alter the effects of cannabinoid agonists and antagonists on the cardiac response to different stimuli. Since no data have shown an interaction between urethane and cannabinoid signaling in epilepsy, we examined the suitability of urethane with regard to testing the effects of a cannabinoid CB1 receptor agonist and an antagonist on penicillin-induced epileptiform activity in rats. Permanent screw electrodes for electrocorticographic (ECoG) recordings, and a permanent cannula for administration of the substances to the brain ventricles, were placed into the cranium of rats. Epileptiform activity was induced by injection of penicillin through the cannula in conscious animal. The CB1 receptor agonist arachidonyl-2-chloroethylamide (ACEA; 7.5 μg) and the CB1 receptor antagonist [N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3 carboxamide] (AM-251; 0.25 μg) were administered intracerebroventricularly 30 minutes after the penicillin application in urethane-anesthetized and conscious animals. Urethane completely eliminated spontaneous ictal events in ECoG recordings and reduced the frequency and total amount of epileptiform activity. It did not alter either the proconvulsant effects of AM-251 or the anticonvulsant effects of ACEA on penicillin-induced epileptiform activity. The electrophysiological evidence suggests that there is no possible interaction between urethane and cannabinoid CB1 receptors in this experimental model of epilepsy.