Direct Current Potential Research Articles

Study of ionic wind based on dielectric barrier discharge of carbon fiber spiral electrode

Based on the idea that a large number of charged particles can be generated by a high-frequency alternating current (AC) dielectric barrier discharge (DBD), and charged particles can be accelerated directionally by a direct current (DC) electric field, a new type of ionic wind formation method is proposed in this paper. To this end, a carbon fiber spiral electrode serves as the generation electrode and a metal rod electrode as the collection electrode, with AC and DC potentials applied respectively to the generation electrode and the collection electrode to form an AC–DC coupled electric field. Under the action of the coupled electric field, a dielectric barrier discharge is formed on the carbon fiber spiral electrode, and the electrons generated by the discharge move from the generation electrode to the collection electrode in the opposite direction of the electric field vectors. During the movement, energy is transferred to the gas molecules by their colliding with neutral gas molecules, thereby forming a directional gas stream movement, i.e. ionic wind. In the research process, it is verified through electric field simulation analysis and discharge experiment that this method can effectively increase the number of charged particles in the discharge process, and the velocity of the ionic wind is nearly doubled. On this basis, the addition of a third electrode forms a distinct discharge region and an electron acceleration region, which further increases its velocity. The experimental result shows that the ionic wind speed reaches up to 2.98 m s−1. Thanks to the ability of the electrode structure to generate an atmospheric pressure DBD plasma and form an ionic wind, we can create a noise-free air purification device without resorting to a fan, with this device having good application prospects in the field of air purification.

CEREBRAL ENERGY METABOLISM IN YOUNG PEOPLE DURING ADAPTATION TO THE CONDITIONS OF THE ARCTIC REGION

Aim. The article deals with determining the features of cerebral energy metabolism in young people at different stages of adaptation in the Arctic region. Materials and methods. The level of permanent brain direct current potentials (DCP) was measured in 146 young people: 93 born and permanently living in the Arctic region and 53 migrants living in new climatic conditions for the first months. The study was conducted by using a “Neuro-KM” 12-channel hardware-software complex for the topographic mapping of brain electrical activity. DCP were recorded in the unipolar leads according to the 10-20 international system. Statistical processing of the data obtained was carried out with the software package SPSS-20 for Windows. Results. In young people permanently living in the Arctic region, we revealed functional asymmetry of the brain with right-hemisphere dominance in almost all leads. In migrants living in the climatic conditions of the Arctic region for the first months, we established high values of energy consumption and partial asymmetry of cerebral energy metabolism. Conclusion. Body functioning in the usual habitat is characterized by a stereotypical set of regulatory mechanisms. During adaptation, new ways of responding to changes in the environment are formed. The dominance of the right or left hemisphere occurs depending on the type of tasks. The analysis of interhemispheric asymmetry of energy consumption performed by using the method of brain mapping allows assessing the degree of dominance. The dominance of energy consumption in the left hemisphere may indicate a possible failure of adaptation mechanisms. Positive interhemispheric gradients indicate the correct performance of CNS regulatory mechanisms during adaptation to new environmental conditions

Decision Support System for Mitigating Athletic Injuries

Abstract The purpose of the present study was to demonstrate an inductive approach for dynamically modelling sport-related injuries with a probabilistic graphical model. Dynamic Bayesian Network (DBN), a well-known machine learning method, was employed to illustrate how sport practitioners could utilize a simulatory environment to augment the training management process. 23 University of Iowa female student-athletes (from 3 undisclosed teams) were regularly monitored with common athlete monitoring technologies, throughout the 2016 competitive season, as a part of their routine health and well-being surveillance. The presented work investigated the ability of these technologies to model injury occurrences in a dynamic, temporal dimension. To verify validity, DBN model accuracy was compared with the performance of its static counterpart. After 3 rounds of 5-fold cross-validation, resultant DBN mean accuracy surpassed naïve baseline threshold whereas static Bayesian network did not achieve baseline accuracy. Conclusive DBN suggested subjectively-reported stress two days prior, subjective internal perceived exertions one day prior, direct current potential and sympathetic tone the day of, as the most impactful towards injury manifestation.

EFFECTS OF HYPERBARIC OXYGEN THERAPY ON THE POST-OPERATIVE PERIOD IN PATIENTS WITH A DIFFERENT FUNCTIONAL STATUS

Aim. To evaluate the effi cacy of hyperbaric oxygenation (HBO) in patients with a different functional status (FS) after the elimination of acute colonic obstruction (ACO).Materials and methods. A retrospective analysis of 210 medical records of patients who had undergone emergency surgical interventions aimed at ACO elimination was carried out. Based on the value of the direct current potential (DCP), the patients were divided into three groups: 1st (n = 96) with the DCP value from –30 mV and below — FS subcompensation; 2nd (n = 60) with average negative DCP values from –15 to –29.9 mV — FS compensation; 3rd (n = 54) with low negative and positive DCP values from –14.9 mV and higher — FS decompensation. The correlation between patients’ FS and the incidence of postoperative complications was studied, and independent predictors of fatal outcomes were identifi ed. Subsequently, a quantitative analysis of complications and mortality was carried out in each group depending on the use of HBO sessions in the postoperative period, followed by an assessment of their effi cacy.Results. According to the number of perioperative complications and mortality, risk groups in terms of the unfavourable course of the postoperative period were identifi ed: patients with high negative DCP values, for whom the arterial hypotension and acute kidney injury (AKI) could serve as the independent predictors of death; and patients with low negative and positive DCP values, for whom the statistically signifi cant predictors of mortality were shown to be the DCP level, hypotension, AKI and pneumonia. HBO sessions in the postoperative period allow the number of complications in the general population to be reduced: pneumonia by 7%, delirium by 8.8%, AKI by 6.3%, intestinal dysfunction for more than 3 days by 7.3%. In addition, HBO contributed to a 2.9% decrease in suppurative diseases. The analysis of the data on the HBO application in the general population and FS information showed HBO to have a positive effect on the general somatic status of ACO patients. In addition, HBO treatment is shown to decrease the incidence of complications in the early postoperative period. The effi cacy of HBO is found to be higher in the cohort of the most severe patients with decompensated FS, where such complications as delirium, pneumonia and gastrointestinal paresis were decreased by 22.2%, 13% and 18.5%, respectively. As a result, in this group of patients, a signifi cant decrease of 11.1% in 30-day mortality was achieved.Conclusion. The postoperative period depends on the actual FS. The conducted analysis of HBO therapy has convincingly confi rmed its effi cacy in the combined treatment of patients after the elimination of ACO.

Kinetics of carbon steel dissolution in ammonium chloride solution containing sodium thiosulfate

AbstractThe dissolution behavior of carbon steel in ammonium chloride (NH4Cl) solution containing sodium thiosulfate (Na2S2O3) of various concentrations (0.01 and 0.1 M) was investigated using electrochemical impedance spectroscopy (EIS) and other nonelectrochemical techniques. The weight loss and polarization measurements indicate a significant increase in the NH4Cl corrosion rate of carbon steel on addition of Na2S2O3. The EIS measurements exhibited two capacitive loops at multiple direct current (dc) potentials for both the concentrations. Electrical equivalent circuit (EEC) and reaction mechanism analysis (RMA) were employed to analyze the impedance data. A four‐step mechanism with two intermediate adsorbate species of same charge was proposed to explain the dissolution behavior of carbon steel in the given system. The surface coverage values enumerated that the surface was entirely covered with adsorbed species unlike in the pure NH4Cl system. Charge transfer resistance and polarization resistance values estimated from RMA parameters indicate the increase in a dissolution rate with dc potential. The surface morphology was inspected via field emission scanning electron microscopy, and the corrosion products including surface state of carbon steel electrode were analyzed using energy dispersive X‐ray spectroscopy and X‐ray photoelectron spectroscopy.

Energy metabolism of the brain in the inhabitants of the arctic zone, depending on the prevalence of vegetative tonus

The study of the physiological mechanisms of human acclimatization to extreme climatic conditions seems to be an urgent task in the current socio-economic conditions of the development of the Arctic territories. The purpose of the study is to determine cerebral energy metabolism in young people in the Arctic region with a different initial autonomic tone. Cerebral energy consumption and heart rate variability were studied in 103 young people (mean age 19 ± 0.22) constantly residing in Arkhangelsk. Research of the energy metabolism of the brain was carried out using the direct current (DC) potential recorded from the scalp. The study of the vegetative regulation of heart rhythm was carried out by cardiac rhythmography with registration of the background electrocardiogram at rest. High values of DC potential were registered in frontal cortex in the group of participants with a predominance of sympathetic nervous system influences. In the group of participants with a predominance of the effects of the parasympathetic nervous system, an increased level of constant potential in occipital cortex, with a decrease DC potential in the temporal and the frontal areas.

Autonomic support of cognitive functions and functional asymmetry in normal aging and chronic cerebrovascular disorders

The increase in life expectancy is accompanied by an increase in the number of patients suffering from chronic cerebrovascular diseases with progressive cognitive decline, up to dementia. Therefore, the search for new approaches to studying the disease pathogenesis, prevention and treatment is relevant. We analysed the data on correlation of cognitive characteristics with reactions of the autonomic nervous system (ANS) and ANS-regulated systems in normal aging and in patients with vascular encephalopathy (VE). Reactivity of cerebral blood flow as a result of cortical-ANS interaction was studied, characteristics of cerebral blood flow influencing the interhemispheric energetic processes (studied with direct current potentials of the brain) were analyzed, and correlation of blood pressure and heart rate with cognitive characteristics were assessed. Since the signs of cognitive decline are observed during normal aging and VE, an attempt was made to analyze the dependence of cognitive and ANS functions not only on VE, but also on the age. We showed some specific features of cortical-ANS interaction in groups of patients divided in accordance with small criteria of functional asymmetry. The obtained results are of value for studying VE pathogenesis and for prognosing cognitive impairment in patients with VE.

Digital mass filter analysis in stability zones A and B.

Digitally driven mass filter analysis is an advancing field. This work presents a tutorial of digital waveforms, stability diagrams, and pseudopotential well plots. Experimental results on digitally driven mass filter analysis in stability zones A and B are also shown. This work explains duty cycle manipulation of the waveforms to axially trap and eject ions from linear quadrupoles and how to change and distort the stability diagrams to create mass filters and their effects on the pseudopotential well depth. It discusses the sensitivity and resolution that can be obtained and what limits these benchmarks. It reveals the advantages of mass filter operation without any added direct current potential between the quadrupole electrodes (a=0).

Intrinsic stresses in Ti1−xAlxN coatings deposited by vacuum arc method

The model of the nonlocal thermoelastic peak of low-energy ion is used in deriving an expression for intrinsic stress in multi-component material deposited from mixed beam of differently charged ions in modes of the direct current (DC) and pulsed bias potential. Calculation of intrinsic stress depending on bias potential in coating Ti1−xAlxN deposited from mixed ion beam Ti + Al with different component ratio is executed in modes of DC and pulsed bias potential at different substrate temperatures. It is shown that the increase of the content x of Al ions in the mixed beam and in deposited Ti1−xAlxN coating reduces the maximum of the stress curve σ(U).

Combined Effect of Alternating Current Interference and Cathodic Protection on Pitting Corrosion and Stress Corrosion Cracking Behavior of X70 Pipeline Steel in Near-Neutral pH Environment.

Influence of alternating current (AC) on pitting corrosion and stress corrosion cracking (SCC) behavior of X70 pipeline steel in the near-neutral pH environment under cathodic protection (CP) was investigated. Both corrosion and SCC are inhibited by −0.775 VSCE CP without AC interference. With the superimposition of AC current (1–10 mA/cm2), the direct current (DC) potential shifts negatively under the CP of −0.775 VSCE and the cathodic DC current decreases and shifts to the anodic direction. Under the CP potential of −0.95 VSCE and −1.2 VSCE, the applied AC current promotes the cathodic reaction and leads to the positive shift of DC potential and increase of cathodic current. Local anodic dissolution occurs attributing to the generated anodic current transients in the positive half-cycle of the AC current, resulting in the initiation of corrosion pits (0.6–2 μm in diameter). AC enhances the SCC susceptibility of X70 steel under −0.775 VSCE CP, attributing to the promotion of anodic dissolution and hydrogen evolution. Even an AC current as low as 1 mA/cm2 can enhance the SCC susceptibility.

Enhancement of ion activation and collision induced dissociation by direct current potential in digital ion trap mass spectrometer

The efficiency of collision induced dissociation (CID) is strongly dependent on the ion activation energy. In order to increase the ion kinetic energy during resonance ion excitation, a DC voltage was deduced by simply changing the duty cycle of digital power supply in this study using a digital linear ion trap. In this experiment, different DC potentials were obtained by choosing different duty cycles of main ion trapping digital waveform, and the waveforms applied to the x and y electrode pairs were kept complimentary during ion activation and CID period. The experimental results shown that the CID efficiency was significantly increased when the DC potential was increased. The observed ion internal energy was increased about 2.5 times, and the CID efficiency was increased from 68% to 93%. A calculation shows that the low mass cut off can also be reduced by 15% and it is in agreement with the experiment results.

Accurate volume integral solutions of direct current resistivity potentials for inhomogeneous conductivities in half space

We develop a novel accurate volume integral formula for solving potentials of three dimensional (3D) direct current resistivity problems with inhomogeneous conductivities in half-space. This new integral formula is composed of the potential, the gradient of Green's function, the gradient of the potential and the anomalous conductivity as the physical variables. First, the unstructured grids are adopted to handle inhomogeneous bodies with complicated shapes. Then, in each anomalous tetrahedron, the potential is represented as its values at vertices and the linear shape functions. Analytical expressions are developed to evaluate singular volume integrals in the final system of linear equations when the observation sites locate in the anomalous body. Finally, two synthetic models are utilized to verify the accuracy and convergence rate of our newly developed volume integral formula and its capability of dealing with complicated models with high conductivity contrasts.

In Vivo Evaluation of Cerebral Hemodynamics and Tissue Morphology in Rats during Changing Fraction of Inspired Oxygen Based on Spectrocolorimetric Imaging Technique.

During surgical treatment for cerebrovascular diseases, cortical hemodynamics are often controlled by bypass graft surgery, temporary occlusion of arteries, and surgical removal of veins. Since the brain is vulnerable to hypoxemia and ischemia, interruption of cerebral blood flow reduces the oxygen supply to tissues and induces irreversible damage to cells and tissues. Monitoring of cerebral hemodynamics and alteration of cellular structure during neurosurgery is thus crucial. Sequential recordings of red-green-blue (RGB) images of in vivo exposed rat brains were made during hyperoxia, normoxia, hypoxia, and anoxia. Monte Carlo simulation of light transport in brain tissue was used to specify relationships among RGB-values and oxygenated hemoglobin concentration (CHbO), deoxygenated hemoglobin concentration (CHbR), total hemoglobin concentration (CHbT), hemoglobin oxygen saturation (StO2), and scattering power b. Temporal courses of CHbO, CHbR, CHbT, and StO2 indicated physiological responses to reduced oxygen delivery to cerebral tissue. A rapid decrease in light scattering power b was observed after respiratory arrest, similar to the negative deflection of the extracellular direct current (DC) potential in so-called anoxic depolarization. These results suggest the potential of this method for evaluating pathophysiological conditions and loss of tissue viability.

Influence of the blood gas transport system on brain millivolt scale direct current potentials in patients with vascular encephalopathy

Introduction . Millivolt Scale direct current potentials (DCP) registered from human scalp differ from other types of estimated electrical activity by closer association with cerebral energetic processes. Intense energy metabolism in the brain increases the difference between acidic products concentrations on both sides of the blood brain barrier which is reflected by higher DCP. Oxygen consumption of is one of the most important components of cerebral energy metabolism. Delivery of oxygen to neuron depends on the characteristics of blood oxygen transport system and cerebral blood flow. Objective . To test the hypothesis that brain DCP depends of the blood oxygen transport system characteristics and cerebral blood flow. Materials and methods. Erythrocytes number, erythrocyte sedimentation rate, hemoglobin and fibrinogen levels in blood were examined i n 135 patients with vascular encephalopathy (VE) Blood flow velocity in major head arteries was estimated using Doppler ultrasound. Associations between blood characteristics and blood flow velocity and the brain DCP, recorded in frontal, central, occipital areas along the midline and in both temporal areas, were determined. Results. Associations between brain DCP and the blood oxygen transport system characteristics as well as the cerebral blood flow velocity were discovered in patients with VE. Averaged values of DCP in all examined areas were significantly different in groups with high and low hemoglobin levels (Fisher coefficient (F) = 5.5; p = 0.02) and corpuscular hemoglobin levels (F = 7.0; p <0.01). The blood flow velocity in the internal carotid artery correlated with DCP in central areas of the head (r = 0.37; p = 0.003). The values of averaged DCP (over all areas) negatively correlated with blood sedimentation rate (r = -0.31; p= 0.002) and fibrinogen levels (r = -0.37; p <0.001). Conclusions . Evidences of the association between DCP and the brain oxygen transport system were obtained. Higher level of hemoglobin and a higher rate of cerebral blood flow promote more intensive rates of brain oxygen consumption. Discovered correlations between the blood oxygen transport system characteristics, cerebral blood flow and brain DCP confirm the potential benefit of using the millivolt range slow brain electrical activity measurement to characterize cerebral energy metabolism in clinical and experimental setting.

Development of Sonogel-Carbon based biosensors using sinusoidal voltages and currents methods

In this work, biosensors based on Sonogel-Carbon electrodes modified with poly(3,4-ethylenedioxythiophene) – tyrosinase biocomposite materials have been developed using sinusoidal voltages and currents methods The sinusoidal voltages method uses a sinusoidal voltage signal of a 50mHz fixed frequency and high amplitude superimposed on a direct current potential to modify the Sonogel-Carbon electrodes surface with the poly(3,4-ethylenedioxythiophene) – tyrosinase layer. A new preparation method involving the application of a sinusoidal current signal with fixed frequency and amplitude over a direct current has been developed as well. The experimental parameters of these methods have been optimized and selected in such a way to highlight the contribution of the sinusoidal component in the biosensors preparation. The advantages of the new preparation methods in terms of electrocatalytic and analytical efficiencies are presented. The analytical performances of the proposed biosensors towards benchmark analytes like dopamine, hydroquinone, and catechol have been investigated. The lowest limit of detection value of 7.10μM and a high sensitivity value of 0.0037μA/μM for dopamine determination were obtained with a biosensor prepared via the new sinusoidal currents method. The biosensors were successfully applied in the quantification of dopamine in pharmaceutical products.

Risk-based underground pipeline safety management considering corrosion effect

Due to the long term usage and irregular maintenance for corrosion checks, catastrophic accidents have been increasing in underground pipelines. In this study, a new safety management methodology of underground pipeline, risk-based pipeline management, is introduced reflecting corrosion effect. First, principle of the risk-based pipeline management is presented compared with an original method, qualitative measure. It is distinguished from the qualitative measure by reflecting societal risk and corrosion in safety management of underground pipeline. And then, it is applied to an existing underground propylene pipeline in Ulsan Industrial Complex, South Korea. The consequence analysis is based on real information, and the frequency analysis reflects degree of corrosion. For calculation of corrosion rate, direct current voltage gradient (DCVG) and close interval potential survey (CIPS) are conducted. As a result of applying the risk-based pipeline management, risk integral is reduced by 56.8% compared to the qualitative measure. Finally, sensitivity analysis is conducted on variables, which affect the risk of the pipeline. This study would contribute to introduce quantitative measure to pipeline management and increase safety of pipeline.

Age or ischemia uncouples the blood flow response, tissue acidosis, and direct current potential signature of spreading depolarization in the rat brain.

Spreading depolarization (SD) events contribute to lesion maturation in the acutely injured human brain. Neurodegeneration related to SD is thought to be caused by the insufficiency of the cerebral blood flow (CBF) response; yet the mediators of the CBF response, or their deficiency in the aged or ischemic cerebral cortex, remain the target of intensive research. Here, we postulated that tissue pH effectively modulates the magnitude of hyperemia in response to SD, the coupling of which is prone to be dysfunctional in the aged or ischemic cerebral cortex. To test this hypothesis, we conducted systematic correlation analysis between the direct current (DC) potential signature of SD, SD-associated tissue acidosis, and hyperemic element of the CBF response in the isoflurane-anesthetized, young or old, and intact or ischemic rat cerebral cortex. The data demonstrate that the amplitude of the SD-related DC potential shift, tissue acidosis, and hyperemia are tightly coupled in the young intact cortex; ischemia and old age uncouples the amplitude of hyperemia from the amplitude of the DC potential shift and acidosis; the duration of the DC potential shift, hyperemia and acidosis positively correlate under ischemia alone; and old age disproportionally elongates the duration of acidosis with respect to the DC potential shift and hyperemia under ischemia. The coincidence of the variables supports the view that local CBF regulation with SD must have an effective metabolic component, which becomes dysfunctional with age or under ischemia. Finally, the known age-related acceleration of ischemic neurodegeneration may be promoted by exaggerated tissue acidosis.NEW & NOTEWORTHY The hyperemic element of the cerebral blood flow response to spreading depolarization is effectively modulated by tissue pH in the young intact rat cerebral cortex. This coupling becomes dysfunctional with age or under ischemia, and tissue acidosis lasts disproportionally longer in the aged cortex, making the tissue increasingly more vulnerable.

The effect of ultraviolet on direct current potentials of the human skin

Aim of the study. investigation of the suntan on the level of omnipresent electrical potential of skin in frames of development of the hypothesis about the melanocyte participation in skin electrical activity formation. Material and methods. 11 men and 11 women on summer holyday took part in investigation. The relationship between the levels of skin omnipresent electrical potential and the reflection factor were investigated. The omnipresent electrical potentials were registered as the potential differences between the two areas on skin using the Orion 261S pH meter and the liquid Ag/AgCl electrodes of the same company. The reflecting factor was estimated with the help of the spectroradiometer LI-1800 (“LI-COR”) using the included intgrational sphere 1800-12 coated with barium sulfate. Hole size was 1,45 cm. The reflection factor was estimated at the wave band 375-800 nanometers with the scanning pitch 1 nm. Main results. There is a mathematical relation between the magnitudes of potential differences and the reflection factors of the areas of sunburnt skin and the areas of the skin not affected with sun at wave light 620-729 nm. The relationship could be approximated in linear equation. Spearman correlation factor between these two parameters was -0,43 (p = 0,045), between the differences in levels of skin omnipresent electrical potential and the reflection factors of the sunburnt skin was r = -0,52 (p = 0,01), between the differences of the electrical potentials of sunburnt skin and the skin not affected with sun was r = -0,28 (p = 0,2). The presented results of investigation and the data from literature allow to conclude that there is a positive correlation between the level of omnipresent electrical potential of skin and the quantity of melanosomes filled with melanin. Conclusion. It is suggested that melanocytes take part in formation of the skin electrical activity via melanosomes filled with melanin. At the same time the melanocyte contribution in skin electrical activity is not assessed.

NADH fluorescence imaging and the histological impact of cortical spreading depolarization during the acute phase of subarachnoid hemorrhage in rats.

OBJECTIVE Although cortical spreading depolarization (CSD) has been observed during the early phase of subarachnoid hemorrhage (SAH) in clinical settings, the pathogenicity of CSD is unclear. The aim of this study is to elucidate the effects of loss of membrane potential on neuronal damage during the acute phase of SAH. METHODS Twenty-four rats were subjected to SAH by the perforation method. The propagation of depolarization in the brain cortex was examined by using electrodes to monitor 2 direct-current (DC) potentials and obtaining NADH (reduced nicotinamide adenine dinucleotide) fluorescence images while exposing the parietal-temporal cortex to ultraviolet light. Cerebral blood flow (CBF) was monitored in the vicinity of the lateral electrode. Twenty-four hours after onset of SAH, histological damage was evaluated at the DC potential recording sites. RESULTS Changes in DC potentials (n = 48 in total) were sorted into 3 types according to the appearance of ischemic depolarization in the entire hemisphere following induction of SAH. In Type 1 changes (n = 21), ischemic depolarization was not observed during a 1-hour observation period. In Type 2 changes (n = 13), the DC potential demonstrated ischemic depolarization on initiation of SAH and recovered 80% from the maximal DC deflection during a 1-hour observation period (33.3 ± 15.8 minutes). In Type 3 changes (n = 14), the DC potential displayed ischemic depolarization and did not recover during a 1-hour observation period. Histological evaluations at DC potential recording sites showed intact tissue at all sites in the Type 1 group, whereas in the Type 2 and Type 3 groups neuronal damage of varying severity was observed depending on the duration of ischemic depolarization. The duration of depolarization that causes injury to 50% of neurons (P50) was estimated to be 22.4 minutes (95% confidence intervals 17.0-30.3 minutes). CSD was observed in 3 rats at 6 sites in the Type 1 group 5.1 ± 2.2 minutes after initiation of SAH. On NADH fluorescence images CSD was initially observed in the anterior cortex; it propagated through the entire hemisphere in the direction of the occipital cortex at a rate of 3 mm/minute, with repolarization in 2.3 ± 1.2 minutes. DC potential recording sites that had undergone CSD were found to have intact tissue 24 hours later. Compared with depolarization that caused 50% neuronal damage, the duration of CSD was too short to cause histological damage. CONCLUSIONS CSD was successfully visualized using NADH fluorescence. It propagated from the anterior to the posterior cortex along with an increase in CBF. The duration of depolarization in CSD (2.3 ± 1.2 minutes) was far shorter than that causing 50% neuronal damage (22.4 minutes) and was not associated with histological damage in the current experimental setting.

Electromagnetic simulations of JET ICRF ITER-like antenna with TOPICA and SSWICH asymptotic codes

Multi-megawatt Ion Cyclotron Range of Frequencies (ICRF) heating is routinely used in the JET tokamak. To increase the ICRF heating power available from the A2 antennas, the ICRF ITER-Like Antenna (ILA) was reinstalled for the 2015 JET ITER-like wall experimental campaign. The application of high levels of ICRF power typically results in increased plasma wall interaction which leads to the observation of enhanced influx of metallic impurities in the plasma edge. It is assumed that the impurity production is mainly driven by the parallel component of the Radio-Frequency (RF) antenna electric near-field, E// (parallel to the confinement magnetic field of the tokamak), that is rectified in a thin boundary layer (RF sheath). Torino Polytechnic Ion Cyclotron Antenna (TOPICA) code was used to compute E// field maps in front of the ILA and between its poloidal limiters in the presence of plasma using measured density profiles and various antenna feedings. E// field maps calculated between the poloidal limiters were used to estimate the poloidal distribution of RF-sheath Direct Current (DC) potential in this private region of the ILA and make relative comparison of various antenna electrical settings. For this purpose we used the asymptotic version of the Self-consistent Sheaths and Waves for Ion Cyclotron Heating Slow-Wave (SSWICH-SW) code. These estimations can help to study the formation of RF sheaths around the antenna and even at distant locations (∼3m away).