Discharge Frequency Research Articles

Comprehensive optical diagnostics for flame behavior and soot emission response to a non-equilibrium plasma

This study reported comprehensive optical diagnostics for flame behavior and soot emission under directly coupling of the plasma with the flame at specific heights. The morphometric parameters of unstable flames under the direct plasma coupling were quantified. We also proposed an optical method to eliminate plasma luminescence from the field of view to extract flame intensity. At the same discharge height, with the increase of discharge frequency, the flame height decreased, while the flame horizontal extension distance and deflection angle increased. The relationships between flame morphologic and electrical parameters were obtained. The experimental results suggested a one-to-one correspondence between plasma action and flame deflection or shortening. When the plasma interacted with the flame, the overall temperature and soot emission of the flame decreased compared with that without plasma. At the same discharge height, the flame temperature and soot decreased further with the increase of discharge frequency. The soot emission changed more remarkably with the discharge frequency for higher discharge heights. With the increase of voltage, the flame temperature and soot increased at the lower discharge heights. The analysis of the experiment data demonstrated that the variation of soot emission was caused by the cooperation of multiple factors.

Control effects of a high-frequency pulsed discharge on a hypersonic separated flow

The control effects of a high-frequency pulsed discharge on a hypersonic separated flow induced by a 42° compression ramp are studied with high-speed schlieren imaging. A discharge is generated between an electrode pair upstream of the ramp to introduce strong disturbances into the boundary layer. The discharge frequencies used are fd = 10, 20, 30, and 40 kHz, with corresponding single-pulse energies Esp = 22.2, 20.3, 12.0, and 8.7 mJ. The results show that the discharge can reduce the separation area, especially with relatively low frequencies of 10 or 20 kHz. The flow mechanism induced by the discharge is scrutinized using a reduced-order method based on the information from time-resolved schlieren images, including proper orthogonal decomposition and dynamic mode decomposition. The results identify an unsteady mode representing regular energetic eddies within the shear layer of the separation zone. This mode has the same characteristic frequency as the discharge. These eddies enhance the mixing of the shear layer and the main flow stream, accelerating the destruction of the shear layer and reducing the separation zone size. The control effectiveness correlates with the scale of the energetic eddies. At frequencies of 10 or 20 kHz, the discharge is more conducive to attenuating the separation because large-scale eddies, excited by higher single-pulse energy, are enhanced as they propagate downstream in the shear layer. By contrast, the control effectiveness deteriorates when the discharge frequency is 30 or 40 kHz because the induced eddies have smaller scales and decay during propagation.

Phytochemical quercetin alleviates hyperexcitability of trigeminal nociceptive neurons associated with inflammatory hyperalgesia comparable to NSAIDs.

Quercetin is a flavonoid that is widely found in fruits and vegetables. Quercetin inhibits cyclooxygenase-2 and modulates voltage-gated ion channels, however, its effect on nociceptive neuron-associated inflammatory hyperalgesia remains unknown. The present study investigated under in vivo conditions whether systemic administration of quercetin attenuates the inflammation-induced hyperexcitability of trigeminal spinal nucleus caudalis (SpVc) neurons associated with mechanical hyperalgesia and compared its effect to the non-steroidal anti-inflammatory drug, diclofenac. Complete Freund’s adjuvant was injected into the whisker pads of rats to induce inflammation, and then mechanical stimulation was applied to the orofacial area to assess the threshold of escape. The mechanical threshold was significantly lower in inflamed rats compared to uninjected naïve rats, and this lowered threshold returned to control levels 2 days after administration of quercetin or diclofenac. The mean discharge frequency of SpVc wide-dynamic range (WDR) neurons to both non-noxious and noxious mechanical stimuli in inflamed rats was significantly decreased after quercetin or diclofenac administration under combination of three anesthetic agents (medetomidine, midazolam and butorphanol). In addition, the increased mean spontaneous discharge of SpVc WDR neurons in inflamed rats significantly decreased after quercetin or diclofenac administration. Similarly, quercetin or diclofenac restored the expanded mean receptive field size in inflamed rats to control levels. In this study, the combination of three anesthetic agents did not result in any obvious “noxious pinch-evoked after discharges” in CFA inflamed day 2 rat as described previously in pentobarbital-anesthetized rats. Together, these results suggest that administration of quercetin attenuates inflammatory hyperalgesia associated with hyperexcitability of nociceptive SpVc WDR neurons via inhibition of the peripheral cyclooxygenase-2 signaling cascade and voltage-gated ion channels. These findings support the proposed potential of quercetin as a therapeutic agent in complementary alternative medicine strategies for preventing trigeminal inflammatory mechanical hyperalgesia.

Inactivation of Escherichia coli by atmospheric pressure plasma jet in water.

The main aim of this work is inactivation of Escherichia coli in water using a laboratory-scale radio-frequency atmospheric pressure Argon plasma jet. This bacterium is widely present in the environment, especially in drinking water, and its pathogenic effects are very harmful. For this purpose, an Argon flow rate of 3.5 slm, maximum plasma power of 200 W, and discharge frequency of 13.56 MHz was conducted to generate a uniform plasma plume for water treatment. 150 ml of drinking water contaminated by E. coli was exposed to the radiation of plasma placed about 3 cm within the water, the treatment time varied from 2 to 6 minutes at 100, 150, and 200 W of plasma input power. The temperature of the plume, discharge current and voltage, and electron density were all measured to characterize the plasma. Active species such as excited molecules, ions, and radicals produced in the plasma in water were detected using the optical emission spectroscopy method. The decreasing behavior of live bacteria versus exposure time and plasma jet input power was observed, and finally, at the discharge power of 200 W and 6 min, an effective inactivation was achieved and the number of bacteria reduced from 92×104 to less than 1.7 MPN/100 ml.

Identification of hepatosensitive region and their neural connections in the hippocampus of rats.

Visceral function localisation of the brain is very complex. For many years, people have been actively exploring the neural mechanism regulating visceral and substance metabolism, clarifying the complex relationship between the brain and peripheral nervous system related to the regulation of visceral activity, and analysing its complex neural pathways. The brain is the advanced centre of visceral function regulation. As an advanced centre for substance metabolism and visceral regulation, the hippocampus is crucial for regulating visceral function. The liver is the core organ of material metabolism, and its afferent signals are mainly projected to the nucleus of the solitary tract (NTS) through vagus nerve, and then they are projected to the hypothalamus and limbic system. We placed a stereotaxic instrument on the head of each rat and performed craniotomy to open a window above the left hippocampus. We used gold-plated tungsten electrodes to monitor hippocampal neuronal discharges. Grounding was achieved using screws and silver wire. We electrically stimulated the liver branch of the vagus nerve and observed changes in hippocampal neuron discharges using a biological method; in this way, we identified hepatosensitive hippocampal region. We injected FluoroGold into this region and related brain areas. After 3 days, the rats were sacrificed and perfused; the hippocampi were fixed, dehydated, frozen, sectioned, and subjected to fluorescence microscopy. Nerve discharge frequency and amplitude significantly increased in the hippocampal CA3 region (AP: -4.9, ML: -5.1, DV: -5.0 mm). After FluoroGold was injected into the left hepatosensitive region in the hippocampus, labelled cells were found in the contralateral hippocampus, ipsilateral piriform cortex (PC), locus coeruleus (LC) and bilateral lateral hypothalamus (LHA); fluorescence in the ipsilateral hypothalamus was stronger than that of the contralateral hypothalamus. FluoroGold was injected into the LHA, PC, and LC; no labelled cells were found in the hippocampal CA3 region or in the control group. The hippocampal CA3 area of rats may contain a hepatosensitive region that plays important roles in the regulation of liver and other organ function. This region may receive input from the LHA, PC, and LC.

Control of flow separation over a wing model with plasma synthetic jets

An array of 30 plasma synthetic jet actuators (PSJAs) is deployed using a modified multichannel discharge circuit to suppress the flow separation over a straight-wing model. The lift and drag of the wing model are measured by a force balance, and the velocity fields over the suction surface are captured by a particle imaging velocimetry system. Results show that the flow separation of the straight wing originates from the middle of the model and expands towards the wingtips as the angle of attack increases. The flow separation can be suppressed effectively by the PSJAs array. The best flow control effect is achieved at a dimensionless discharge frequency of F + = 1, with the peak lift coefficient increased by 10.5% and the stall angle postponed by 2°. To further optimize the power consumption of the PSJAs, the influence of the density of PSJAs on the flow control effect is investigated. A threshold of the density exits (with the spanwise spacing of PSJAs being 0.2 times of the chord length in the current research), below which the flow control effect starts to deteriorate remarkably. In addition, for comparison purposes, a dielectric barrier discharge (DBD) plasma actuator is installed at the same location of the PSJAs. At the same power consumption, 4.9% increase of the peak lift coefficient is achieved by DBD, while that achieved by PSJAs reaches 5.6%.

Testicular androgens determining the incidence of spike-wave discharges in taiep rats: A model of H-ABC leukodystrophy

Absence seizures are characterized as a generalized type of epilepsy that occurs during childhood. Importantly, absence seizures in children often discontinue after puberty. There is limited availability of animal models in which electroencephalography (EEG) can be performed in the long term; however, two absence seizure models, GAERS and WAG/Rij albino rats, are available. The taiep rat is a myelin mutant rat with tubulinopathy due to a tubulin β 4A gene mutation and characteristic spike-wave discharges (SWDs) that mimic absence seizure epilepsy in humans and the above rat models. This study aimed to analyze spike-wave discharges after an orchiectomy was performed on postnatal day (PND) 2 or PND 90 in adult rats; and SWDs was recorded in both groups on PND 104. The results suggest that androgens play a critical role in susceptibility to SWDs. In fact, orchiectomy during the neonatal period significantly reduced the frequency of spike-wave discharges. However, if an orchiectomy was performed in adulthood, then SWDs were significantly increased. The mean duration of spike-wave discharges did not differ among the groups tested. Acute administration of testosterone (1 mg/kg) did not change the frequency or duration of spike-wave discharges in the control group or both orchiectomized groups. Overall, this study is the first to show a dichotomic influence of testicular androgens on spike-wave discharges. These findings will have implications in children with this type of generalized epilepsy and may explain the disappearance of absence epilepsy in two-thirds of patients after puberty.

Activation of δ-opioid Receptors in Anterior Cingulate Cortex Alleviates Affective Pain in Rats

The negative emotions caused by persistent pain, called affective pain, are known to seriously affect human physical and mental health. The anterior cingulate cortex (ACC), especially the rostral ACC (rACC) plays a key role in the development of this affective pain. N-methyl-d-aspartate (NMDA) receptors, which are widely distributed in the ACC, are involved in the regulation of emotional behavior. It is well known that activation of opioid receptors can relieve pain, but whether it can alleviate affective pain is not clear. In the present study, conditioned place avoidance (CPA) responses induced by complete Freund's adjuvant (CFA) were used to represent the affective pain of place aversion. The behavioral measurements were synchronously combined with multichannel electrophysiological recordings of the discharge frequency of rACC pyramidal neurons to explore whether affective pain could be alleviated by the synthetic opioid [D-Ala2, D-Leu5]-Enkefalin (DADLE), an agonist of δ-opioid receptors. To further investigate this treatment as a mechanism for the relief of affective pain in CFA-treated animals, we used whole-cell patch recordings in slice preparations of the rACC region to determine the dose-dependent effects of DADLE on NMDA receptor-mediated currents. Then, western blot was used to determine levels of phosphorylated NMDA receptor subunits GluN1, GluN2 and GluN3 as affected by the δ-opioid receptor activation. The results showed that activation of δ-opioid receptors down-regulates the phosphorylation of NMDA receptor subunits, thereby inhibiting NMDA currents, decreasing the discharge frequency of rACC pyramidal neurons, and reversing the CPA response. Thus, δ-opioid receptor activation in the rACC region can alleviate affective pain.

L-Theanine Reduces Epileptiform Activity In Brain Slices

L-Theanine Reduces Epileptiform Activity In Brain Slices ABSTRACT Objective: L-theanine is one of the main amino acid of tea plant which can cross the blood brain barrier. In the central nervous system, L-theanine has certain effects on a number of neurotransmitter systems. In this study we tested whether acute application of L-theanine could induce any seizure like or inhibitory activity in the brain slice. Materials and Methods: Effects of L-theanine on epileptiform activity were investigated in two different brain regions. Horizontal hippocampal-entorhinal cortex slices were obtained from 30-35 days old C57BL/6 mice. Extracellular field potentials were recorded from medial entorhinal cortex (EC) and CA3 region of hippocampus. Epileptiform activity was induced by application of 4 Aminopyridine (4AP, 100 µM) in the brain slices and 50 µM L-theanine was applied. From the recordings, the duration and frequencies of ictal like events as well as frequency and amplitude of inter-ictal like activities were calculated. Results: L-theanine alone did not initiate any synchronized activity. Although, bath application of L-theanine after 4AP induces epileptiform acitivities, did not significantly alter the duration and frequency of ictal discharges, L-theanine attenuated the interictal discharges. In EC the frequencies of interictal discharges were significantly decreased. In CA3, the amplitudes of interictal activities were significantly reduced. Conclusion: The present findings suggest that L-theanine do not induce any seizure like event but rather had a suppressive effect on ongoing epileptiform activity. Key Words: Theanine, 4 Aminopyridine, Brain Slice, Epileptiform activity, CA3, Entorhinal cortex

Changes in PVN Neurons after Low‐Frequency Acute Optogenetic Stimulation

The paraventricular nucleus of the hypothalamus (PVN) is an important autonomic control center. It receives afferent inputs from many brain regions, including the median preoptic nucleus (MnPO). The connection between the MnPO and the PVN is particularly important in generating chronic intermittent hypoxia phenotypes such as increased sympathetic activity leading to the development of hypertension. PVN‐projecting MnPO neurons discharge frequency is <5Hz. To gain more insight into the acute change in PVN neuron properties after low‐frequency stimulation, whole‐cell patch‐clamp recordings were performed on PVN neurons. Adult 250‐350g male rats were injected bilaterally in the PVN with 100 nL retrogradely transported adeno‐associated virus encoding Channelrhodopsin (AAVrg‐CaMKIIa‐hChR2(H134R)‐mCherry) or with AAVrg‐CAG‐tdTomato as control. Three weeks after the injections, the rats were anesthetized with isoflurane (2‐3%) and sacrificed to prepare horizontal brain slices containing the PVN and MnPO. Postsynaptic currents were recorded from PVN neurons in whole‐cell voltage clamp configuration (Vhold=‐60 mV) under constant bath perfusion of normal aCSF (2‐3 ml/min). Axon terminals in the PVN were stimulated with 5Hz LED‐generated blue light (470nM) pulses of 50‐ms duration, 5 seconds off/on for a total of 1 min, delivered using optical fiber directed to the MnPO. Photo‐evoked currents were measured during 5 min before and after the photo‐stimulation train. Amplitude and frequency of spontaneous currents were compared before and after stimulation as well. At the end of each recording, cells were characterized as type I (magnocellular) or type II (parvocellular) PVN neurons based on the presence of transient outward rectification. Data were analyzed offline using Easy Electrophysiology v2.3.3 software. For both cell types, 5 Hz optogenetic stimulation caused a significant reduction in the optogenetic‐evoked current amplitude during the first 15 minutes after stimulation (before stimulation 94.88±2.85 %, n=9 cells vs. 15 minutes after stimulation 67.52±6.15 %, n=9. P=0.0027) before returning to baseline values. Post‐stimulation spontaneous postsynaptic current amplitude and frequency decreased in type II PVN neurons from retrograde ChR2 animals (pre‐stimulation amplitude 100±0.62 % vs. post‐stimulation amplitude 86.50±0.54 %, P=0.0371; pre‐stimulation frequency 3.82±1.7 Hz, post‐stimulation frequency 2.396±1.2 Hz, P= 0.0385) but not in type I PVN neurons from retrograde ChR2 animals or cells from control animals. Kinetic profiles of spontaneous current in type I and II PVN neurons did not change after 5 Hz optogenetic stimulation. The results suggest that low‐frequency stimulation discriminately alters spontaneous presynaptic neurotransmitter release and possibly postsynaptic responsiveness in PVN neurons. Additional experiments will be needed to specifically stimulate PVN afferents from the MnPO.

Microglia-derived TNF-α inhibiting GABAergic neurons in the anterior lateral bed nucleus of the stria terminalis precipitates visceral hypersensitivity induced by colorectal distension in rats

Irritable bowel syndrome (IBS) is a common and debilitating gastrointestinal disorder that is exacerbated by stress and characterized by abdominal pain. Although microglia in the CNS have been implicated as an important mediator of the stress response, the role of microglia and microglia-GABAergic neuron interactions in the limbic area, most notably BNST, in the development of colorectal hypersensitivity has not been determined. We established a neonatal colorectal distension-induced chronic visceral hyperalgesia model in rats. The results showed that the frequency of spontaneous discharges of alBNST GABAergic neurons and the expression of GAD65/67 were significantly decreased in rats with chronic visceral pain. Moreover, ablation of BNST GABAergic neurons significantly reduced the visceral pain threshold in normal rats. Meanwhile, the number of M1 proinflammatory microglia and the expression of the M1 proinflammatory microglia-derived cytokines IL-6 and TNF-α were increased in the alBNST of rats with chronic visceral pain. Furthermore, alBNST infusion of the microglial inhibitor minocycline or IL-6 and TNF-α neutralizing antibodies significantly increased the visceral pain threshold. The decreased frequency of spontaneous discharges of alBNST GABAergic neurons in rats with chronic visceral pain was mimicked by a bath perfusion of TNF-α, but not IL-6, and was abolished by a perfusion of the microglial inhibitor minocycline. In addition, the alBNST infusion of the microglial inhibitor minocycline upregulated the expression of GAD65/67. Moreover, ablation of BNST GABAergic neurons significantly decreased the visceral pain threshold in normal rats, which was not reversed by a subsequent infusion of the microglial inhibitor minocycline. Our findings revealed this microglia-GABAergic neuron circuit in the alBNST, and this microglia-driven disinhibitory mechanism is essential for brain and gut dysfunction in stressful condition, providing a novel potential target for treating patients with IBS presenting visceral pain that is worsened during episodes of stress.

The Effect of Discharge Frequency of a Gas–Liquid Plasma Reactor on Bulk Liquid Transport and Removal of Organic Contaminants

The Effect of Discharge Frequency of a Gas–Liquid Plasma Reactor on Bulk Liquid Transport and Removal of Organic Contaminants

Inhibition of corrosion causing Pseudomonas aeruginosa using plasma-activated water.

The cost of Microbiologically Influenced Corrosion (MIC) significantly affects a wide range of sectors. This study aims to assess the efficiency of a novel technology based on the use of plasma-activated water (PAW) in inhibiting corrosion caused by bacteria. This study evaluated the effectiveness of PAW, produced by a plasma bubble reactor, in reducing corrosion causing Pseudomonas aeruginosa planktonic cells in tap water and biofilms were grown onto stainless steel (SS) coupons. Planktonic cells and biofilms were treated with PAW at different discharge frequencies (500-1500Hz) and exposure times (0-20min). P. aeruginosa cells in tap water were significantly reduced after treatment, with higher exposure times and discharge frequencies achieving higher reductions. Also, PAW treatment led to a gradual reduction for young and mature biofilms, achieving >4-Log reductions after 20min. Results were also used to develop two predictive inactivation models. This work presents evidence that PAW can be used to inactivate both planktonic cells and biofilms of P. aeruginosa. Experimental and theoretical results also demonstrate that reduction is dependent on discharge frequency and exposure time. This work demonstrates the potential of using PAW as means to control MIC.

The antimicrobial efficacy of plasma-activated water against Listeria and E. coli is modulated by reactor design and water composition.

This study aimed to compare the efficacy of plasma-activated water (PAW) generated by two novel plasma reactors against pathogenic foodborne illness organisms. The antimicrobial efficacy of PAW produced by a bubble spark discharge (BSD) reactor and a dielectric barrier discharge-diffuser (DBDD) reactor operating at atmospheric conditions with air, multiple discharge frequencies and Milli-Q and tap water, was investigated with model organisms Listeria innocua and Escherichia coli in situ. Optimal conditions were subsequently employed for pathogenic bacteria Listeria monocytogenes, E. coli and Salmonella enterica. DBDD-PAW reduced more than 6-log of bacteria within 1min. The BSD-PAW, while attaining high log reduction, was less effective. Analysis of physicochemical properties revealed that BSD-PAW had a greater variety of reactive species than DBDD-PAW. Scavenger assays designed to specifically sequester reactive species demonstrated a critical role of superoxide, particularly in DBDD-PAW. DBDD-PAW demonstrated rapid antimicrobial activity against pathogenic bacteria, with superoxide the critical reactive species. This study demonstrates the potential of DBDD-PAW produced using tap water and air as a feasible and cost-effective option for antimicrobial applications, including food safety.

Self-Powered Galvanic Vibration Sensor.

The development of the IoT demands small, durable, remote sensing systems that have energy harvesters and storage. Various energy harvesters are developed, including piezoelectric, triboelectric, electromagnetic, and reverse-electrowetting-on-dielectric. However, integrating energy storage and sensing functionality receives little attention. This paper presents an electrochemical vibration sensor with a galvanic cell (Zn-Cu cell) as energy storage and a vibration transducer. The frequency response, scale factor, long-term response, impedance study, and discharge characteristics are given. This study proved the possibility of integrating energy storage and vibration sensing functionality with promising performance. The performance of the sensor halved within 74 min. The longevity of the sensor is short due to the spontaneous reactions and ions drained. The sensitivity can be restored after refilling the electrolyte. The sensor could be rechargeable by changing to a reversible electrochemical system such as a lead–acid cell in the future.

A pilot-scale study of the integrated floc-ultrafiltration membrane-based drinking water treatment process

Although applications of the integrated ultrafiltration (UF) membrane have been investigated for years, most studies have been conducted at the lab scale. Here, a case study on the integrated Fe-based floc-UF process was presented. To enhance membrane performance, both pre-filtration (bag filter) and pre-oxidation were used as pretreatments to remove particles and inhibit the development of microorganisms. Results showed that the integrated process operated stably with pre-treatments, and the UF membrane fouling behavior could be divided into three different phases: slow increase rate (phase I), medium increase rate (phase II), and fast increase rate (phase III). In comparison to those in phases II and III, both natural organic matters and colloids were the main membrane fouling mechanisms during phase I, as the pollutants were not successfully removed by flocs initially. With the continuous injection of flocs, a loose cake layer became the main fouling mechanism during phase II, resulting in the deterioration of membrane fouling. During phase III, however, microorganisms (e.g., Proteobacteria) were inevitably nourished within the cake layer and played an important role in aggravating the degree of membrane fouling. During this integrated membrane-based process, several operating factors, including floc concentration, sludge discharge frequency, and the aeration rate during backwashing, played important roles in determining membrane performance. In addition, except for oxygen consumption, all the effluent quality parameters met the drinking water criteria followed in China (GB5749-2006).

Improvement in energy channelization behaviour during micro hole formation in Y-SZ ceramic with magnetic field assisted ECSM process

In the present investigation, an energy channelization behavior was improved while machining micro holes in the Yttria–stabilized zirconia (Y-SZ) under magneto hydrodynamic conditions. The integration of magnetic field with electrochemical spark machining (ECSM) process forms the stable and thin gas film on the tool electrode. The subsequent breakdown of this film improves the discharge frequency and increases the discharge current by 18%. The underlying process and material removal mechanisms were demonstrated by using the evidence from discharge signals, gas film images, SEM, and optical images of work material. The stirring action provided by the magnetic field in ECSM process helps to flush out the sludge and stray bubbles from the machining region. In comparison to the ECSM process, the hole depth and aspect ratio were improved by 84.37% and 120%, respectively. Thermal spalling is the leading phenomenon in the material removal process for Y-SZ instead of melting and chemical etching, as in the case of glass substrates. Energy channelization analysis is also carried out to establish the correlations between energy-based parameters and responses. The combination of higher applied energy with small pulse durations is suggested to produce deep holes. The parametric investigation, regression modeling, and optimization for the MFA-ECSM process are also carried out to explore the process behavior.

Research on the Induced Electrostatic Discharge of Spacecraft Typical Dielectric Materials under the ESD Pulse Irradiation.

Based on polyimide (PI), epoxy resin (EP), polytetrafluoroethylene (PTFE) typical dielectric materials used in spacecraft, a research platform for charge-discharge experiment under strong field was established. The influence of irradiation field strength, beam energy, dielectric thickness, etc., on electrostatic discharge characters of dielectric materials were studied and summarized. The results show that with the increase of field strength, the frequency of induced electrostatic discharge increases, the accumulated charge on the dielectric surface decreases, and the dielectric surface potential decreases; Under the same conditions, PI has the lowest discharge frequency and the highest surface dynamic balance potential. The thicker the dielectric material, the lower the discharge frequency, the higher the surface dynamic equilibrium potential; The shape and size of the background electrodes also affect the discharge frequency. When the area is the same, the sharper the electrode edge, the higher the discharge frequency. When the shape is the same, the larger the grounding area, the higher the discharge frequency. By proposing the induced discharge test method, the function mechanism of spatial environmental factors on the electrostatic discharge of typical dielectric materials are obtained. Comparative analysis on electrostatic properties of different dielectric materials can provide data reference and technical support for spacecraft electrostatic safety and protection.

The Isolated Mouse Jejunal Afferent Nerve Assay as a Tool to Assess the Effect of Botulinum Neurotoxins in Visceral Nociception.

For the past two decades, botulinum neurotoxin A (BoNT/A) has been described as a strong candidate in the treatment of pain. With the production of modified toxins and the potential new applications at the visceral level, there is a real need for tools allowing the assessment of these compounds. In this study, we evaluated the jejunal mesenteric afferent nerve assay to investigate BoNT/A effects on visceral nociception. This ex vivo model allowed the continuous recording of neuronal activity in response to various stimuli. BoNT/A was applied intraluminally during three successive distensions, and the jejunum was distended every 15 min for 3 h. Finally, samples were exposed to external capsaicin. BoNT/A intoxication was validated at the molecular level with the presence of cleaved synaptosomal-associated protein of 25 (SNAP25) in nerve terminals in the mucosa and musculosa layers 3 h after treatment. BoNT/A had a progressive inhibitory effect on multiunit discharge frequency induced by jejunal distension, with a significant decrease from 1 h after application without change in jejunal compliance. The capsaicin-induced discharge was also affected by the toxin. This assay allowed the description of an inhibitory effect of BoNT/A on afferent nerve activity in response to distension and capsaicin, suggesting BoNT/A could alleviate visceral nociception.

A secondary motor area contributing to interlimb coordination during visually guided locomotion inthecat.

We investigated the contribution of cytoarchitectonic cortical area 4δc, in the caudal bank of the cruciate sulcus of the cat, to the control of visually guided locomotion. To do so, we recorded the activity of 114 neurons in 4δc while cats walked on a treadmill and stepped over an obstacle that advanced toward them. A total of 84/114 (74%) cells were task-related and 68/84 (81%) of these cells showed significant modulation of their discharge frequency when the contralateral limbs were the first to step over the obstacle. These latter cells included a substantial proportion (27/68 40%) that discharged between the passage of the contralateral forelimb and the contralateral hindlimb over the obstacle, suggesting a contribution of this area to interlimb coordination. We further compared the discharge in area 4δc with the activity patterns of cells in the rostral division of the same cytoarchitectonic area (4δr), which has been suggested to be a separate functional region. Despite some differences in the patterns of activity in the 2 subdivisions, we suggest that activity in each is compatible with a contribution to interlimb coordination and that they should be considered as a single functional area that contributes to both forelimb-forelimb and forelimb-hindlimb coordination.