Needle Electrode Research Articles

피부 부착 전극을 이용한 후두 신경 감시술

Recently, Intraoperative nerve monitoring during thyroidectomy has gained its popularity. There are many methods to perform nerve monitoring including electromyography tube electrode, needle electrode, and skin electrode. However, using needles during thyroid surgery may lead to bleeding or unexpected injury. Herein, effectiveness and safety of skin electrode neuromonitoring and literature is reviewed.

Synchronized 3D Printing and Corona Charging for One-Step Prototyping of Polarized Polylactic Acid Electrets.

Three-dimensional (3D) printing technology is advantageous in the fast prototyping of complex structures, but its utilization in functional material fabrication is still limited due to a lack of activation capability. To fabricate and activate the functional material of electrets, a synchronized 3D printing and corona charging method is presented to prototype and polarize polylactic acid electrets in one step. By upgrading the 3D printer nozzle and incorporating a needle electrode to apply high voltage, parameters such as needle tip distance and applied voltage level were compared and optimized. Under different experimental conditions, the average surface distribution in the center of the samples was -1498.87 V, -1115.73 V, and -814.51 V. Scanning electron microscopy results showed that the electric field contributes to keeping the printed fiber structure straight. The polylactic acid electrets exhibited relatively uniform surface potential distribution on a sufficiently large sample surface. In addition, the average surface potential retention rate was improved by 12.021-fold compared to ordinary corona-charged samples. The above advantages are unique to the 3D-printed and polarized polylactic acid electrets, proving that the proposed method is suitable for quickly prototyping and effectively polarizing the polylactic acid electrets simultaneously.

Mechanism and Experimental Study on Electrostatic Atomization Using Needle-Shaped Electrodes

The conventional pneumatic Minimum Quantity Lubrication (MQL), when not properly designed, may have poor atomization and insufficient wetting performance, resulting in higher oil mist concentration and poor film formation ability in the cutting zone. The intervention of an external electric field can change the atomization mechanism of microdroplets and enhance the lubrication and cooling capability of MQL. However, the mechanism of the effect of jet parameters on the atomization performance of Electrostatic Minimum Quantity Lubrication (EMQL) under the synergistic effect of multiple fields has not been fully analyzed. In this paper, based on the designed needle electrode charging nozzle, the atomization medium charging and atomization mechanisms are investigated, and a mathematical model of the volume average diameter of droplets (VAD) is established. Based on multi-parameter atomization experiments, the electrode conical jet atomization model is validated and the mechanism of the influence of jet parameters on the atomization characteristics is analyzed. The results show that the VAD is negatively correlated with air pressure and electrical. The atomization performance of the droplets was improved under the applied voltage condition, which was manifested by the obvious refinement of the VAD, with a maximum reduction of 34.67%, a maximum reduction of 20% in the droplet group size distribution span (R.S.), and a different degree of reduction in the percentage concentration of fine particulate matter. In addition, the model fitted well with the experimental values, with an overall error of about 10%.

Clinical significance of conduction velocity orientation vectors on cardiac mapping surfaces

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): This work was supported by the Lefoulon Delalande Foundation OBJECTIVE Electroanatomical maps using automated conduction velocity (CV) algorithms are now being calculated using 2D mapping tools. The basis of substrate-based functional assessment is to detect slow zones or slow CV of which isochronal late activation mapping (ILAM) is now commonly performed. We studied the accuracy of mapping surface 2D CV, compared to the 3D vectors, and the influence of mapping resolution in non-scarred animal and human heart models. Methods Two models were used: a healthy porcine Langendorff model with transmural needle electrodes and a computer stimulation model of the ventricles built from an MRI-segmented, excised human heart. Local activation times (LAT) within the 3D volume of the mesh were used to calculate true 3D CVs (direction and velocity) for different pixel resolutions ranging between 500 mm – 4 mm (3D CVs). CV was also calculated for endocardial surface-only LATs (2D CV). Results In the experimental model, surface (2D) CV was faster on the epicardium (0.509 m/s) compared to the endocardium (0.262 m/s, Figure 1). In stimulation models, 2D CV significantly exceeded 3D CVs across all mapping resolutions and increased as resolution decreased (Figure 2). 3D and 2D left ventricle CV at 500mm resolution increased from 429.2±189.3 mm/s to 527.7±253.8 mm/s (P<0.01), respectively with modest correlation (R=0.64). Decreasing the resolution to 4mm significantly increased 2D CV and weakened the correlation (R=0.46). The majority of CV vectors were not parallel (<30°) to the mapping surface providing a potential mechanistic explanation for erroneous LAT-based CV over-estimation. Conclusion Ventricular CV is overestimated when using 2D LAT-based CV calculation of the mapping surface and is significantly compounded by mapping resolution. These findings have implications for the current methodology of functional substrate assessment with ILAM and surface CV assessment.

DNA Nanopore-Tethered Gold Needle Electrodes for Channel Current Recording.

Synthetic DNA nanopores are attracting attention as alternatives to conventional biological nanopores in nanopore sensors because of the high designability of their pore structures and functionability. However, the efficient insertion of DNA nanopores into a planar bilayer lipid membrane (pBLM) remains challenging. Although hydrophobic modifications such as the use of cholesterol are required to insert DNA nanopores into pBLMs, these modifications also induce negative effects, including the undesired aggregation of DNA structures. Herein, we describe an efficient method to insert DNA nanopores into pBLMs and measure the channel currents of DNA nanopores using a DNA nanopore-tethered gold electrode. When the pBLM is formed at the electrode tip by immersing the electrode into a layered bath solution comprising an oil/lipid mixture and an aqueous electrolyte, the electrode-tethered DNA nanopores are physically inserted into the pBLM. In this study, we designed a DNA nanopore structure that can be immobilized on the gold electrode based on a reported six-helix bundle DNA nanopore structure and prepared DNA nanopore-tethered gold electrodes. Thereafter, we demonstrated the channel current measurements of the electrode-tethered DNA nanopores, and a high insertion probability of the DNA nanopores was achieved. We believe that this efficient DNA nanopore insertion method can accelerate the application of DNA nanopores in stochastic nanopore sensors.

Blood-saving dissection with monopolar tungsten needle electrodes and Teflon-coated spatula electrodes in tumor orthopedics

IntroductionResection of musculoskeletal tumors and reconstruction with tumor endoprostheses often results in blood loss requiring transfusion of blood products. We assessed the blood-saving potential of using monopolar tungsten needle electrodes and polytetrafluoroethylene (PTFE)-coated spatula electrodes (intervention) compared with conventional dissection with sharp instruments and coagulation with uncoated steel electrodes (control).MethodsWe retrospectively analyzed data of 132 patients (79 interventions, 53 controls) undergoing surgery by one single experienced surgeon in our tertiary referral center between 2012 and 2021.ResultsIntraoperative blood loss in the intervention group was reduced by 29% [median (IQR): 700 (400–1200) vs 500 (200–700) ml; p = 0.0043]. Postoperative wound drainage decreased by 41% [median (IQR): 1230 (668–2041) vs 730 (450–1354) ml; p = 0.0080]. Additionally, patients in need of PRBCs during surgery declined from 43% to 15% (23/53 vs 12/79; p = 0.0005), while the transfusion rate after surgery did not change notably. The number of patients in need of revision surgery due to wound healing disorders was low in both groups (control group: 4/53 vs intervention group: 4/79). Only one patient in the control group and two patients in the intervention group underwent revision surgery due to hemorrhage. Baseline characteristics were similar between groups (sex, Charlson Comorbidity score, tumor entity).ConclusionDissection with tungsten needle electrodes and PTFE-coated spatula electrodes appears an effective surgical blood-saving measure without increased risk of wound healing disorders.Level of evidenceIII, retrospective comparative study.Clinical trial registration. The study was registered at ClinicalTrials.gov. Identifier: NCT05164809.

Electrical promontory stimulation test using a portable peripheral nerve stimulator with an ear canal electrode

ObjectiveAn intact cochlear nerve is necessary for successful cochlear implantation (CI). Although the promontory stimulation test (PST) using a promontory stimulator (PS) and a transtympanic needle electrode is invasive, it is still commonly used to verify cochlear nerve function. PSs are currently unavailable because they are no longer manufactured; however, considering that PST continues to be beneficial in certain situations, alternative equipment is needed. The PNS-7000® (PNS) was developed as a neurologic instrument for stimulating the peripheral nerves. This study investigated the usefulness of the ear canal stimulation test (ECST) using PNS with a silver ball ear canal electrode, which is a new noninvasive alternative technique to the PST. MethodsECST was performed from November 2013 to December 2018 using PS and PNS for patients with severe to profound sensorineural hearing loss. The electrical threshold, most comfortable loudness level, uncomfortable loudness level, dynamic range, and gap detection were measured in the ECST. The results of these measured PNS items were compared with PS. ResultsECST was performed in 61 ears of 35 patients (age, 59.9 ± 20.1 years) using PS and PNS. The sound sensation was elicited in 51 (83.6%) and 52 (85.2%) ears with PS and PNS, respectively. All items excluding GAP were measured in 46 (75%) and 43 (70%) ears at 50 and 100 Hz, respectively. GAP was measured in 33 ears by the ascending and descending methods using PS and PNS. Spearman's rank-order correlation coefficient revealed a significant positive linear correlation between the PS and PNS results in all measurements. No significant difference was found between the PS and PNS thresholds in all measured items. ConclusionsPNS is a useful instrument for performing ECST as a new alternative to PS. ECST using a silver ball electrode is a less invasive and easier test than PST.

Acute airway obstruction requiring nasotracheal intubation following hypoglossal neuromonitoring: a case report

BackgroundIntraoperative neurophysiological monitoring (IONM) is utilized for both the localization of critical structures and for real time detection and prevention of intraoperative neurological injury. Use of IONM to monitor the hypoglossal nerve is performed during neurosurgical, otolaryngological, and vascular procedures to improve surgical outcomes. There is a paucity of literature describing potential complications of IONM of the hypoglossal nerve, especially with respect to airway compromise. Here we present our findings regarding a case of acute airway obstruction following hypoglossal nerve monitoring.Case PresentationA 54-year-old male was admitted for left far-lateral craniotomy and microsurgical clipping of a left posterior inferior cerebellar artery (PICA) aneurysm. Following induction and intubation but prior to the procedure start, the patient was placed in the ¾ prone position with the left side up and his neck was flexed approximately 10 degrees. He then underwent placement of subdermal needle electrodes into the facial muscles, trapezius muscles, soft palate, and tongue for IONM. The procedure lasted 523 minutes and was completed without complication. However, approximately one hour after emergence from general anesthesia, the patient experienced progressive difficulty breathing secondary to severe lingual swelling. He required emergent placement of a nasotracheal tube guided by a fiberoptic bronchoscope. He remained intubated for 3 days and was treated with dexamethasone, after which the swelling resolved, and the patient was successfully extubated.ConclusionsAcute lingual edema is a potentially life-threatening phenomenon that can lead to rapid airway compromise. Generally, causes of acute lingual swelling include hemorrhage, edema, infarction, and infection. In the case described above, we suspect traumatic injury to the tongue’s vascular supply caused a deep tissue hematoma leading to postoperative acute lingual swelling and airway obstruction. With the widespread use of IONM, it becomes essential for providers to be aware that perioperative airway compromise is a potentially life-threatening complication, especially with respect to monitoring of the hypoglossal nerve. Awake fiberoptic nasotracheal intubation can successfully be employed to establish an emergency airway in such situations.

PO-03-067 POTENTIAL NEGATIVE IMPACT OF IN SITU LARGE LESION FORMATION IN PORCINE AND CANINE ANIMALS

A significant amount of information regarding large lesion formation has emerged over the last 5 – 6 years. Extensive studies have been performed with needle electrode, PFA ablation and protons. The consequence of large lesions have not been analyzed in the intact heart in situ. This study aim was to compare how large lesions were created by needle and proton beam ablation in animal models, and to establish adequate energy power. Twenty-two dogs underwent ablation with a needle electrode. The effect of large lesions from proton therapy was also examined in 28 pigs. The lesion size, potential myocardial disruption, or perforation were examined in each of these animal sets. Similarly, findings from PFA ablation were considered. Of these animals, 35 had normal myocardium, while 15 had undergone prior infarction creation. The target location for needle electrode ablation was established by ultrasound, CT and MR, while CT and MR were utilized for establishing the dose response range and targets for proton therapy. These were examined ultimately by an MR study immediately before animal euthanasia, where upon the lesion size was established. In the animals with normal myocardium, the lesions were largely confined to the desired target. Lesions were of substantial size with 1038 ± 887 mm3 from needle electrodes, and 3500 ± 2100 mm3 from protons. In contrast, with myocardial infarction, there was a ven overlap between the lesion created by myocardial infarction and that created by either needle or proton deliveries. The needle electrode and proton delivery large lesions were seen in the table. The large lesions were confined to the area of the infarct in those animals. There was relatively little scatter of demonstrable lesions in the residual myocardium at risk. There were regions around both needle electrode and proton beam deliveries consistent with lower outputs in both cases. In needle electrode deliveries was significant edema farfield around the major lesion, while there was some penumbral proton effect at levels of 10-20 Gy. Both needle, proton, and PFA deliveries create very large lesions in ventricular myocardium. While this could be of substantial risk, the overall lesions are confined to the target dose of needle/PFA and proton targets. This indicates there is relatively little damage to residual myocardium at risk without negative of decreased myocardial contraction. This must be carefully determined, in setting temperature, radiation, and PFA dosing.Tabled 1Table (PO-03-067)Needle normal tissueNeedle infarct tissueProton normal tissueProton infarct tissuePower40 W/50 s50 W/60 s40 W/50 s30 Gy40 Gy40 GyLesion volume (mm3)983±9061093±8681052±5432500±8005900±9003476±1018Width (mm)17.3±5.823.6±14.914.0±3.722.4±3.432.1±7.825.1±3.6Length (mm)14.9±5.914.7±4.217.1±5.413.3±2.114.9±3.613.8±3.4Depth (mm)13.4±2.913.4±3.315.3±2.213.7±2.515.5±3.714.3±2.8Depth at maximum width (mm)7.6±2.18.3±2.37.9±1.79.4±3.19.1±2.49.2±2.0 Open table in a new tab

Neuromuscular coupling of obligatory respiratory muscles to inspiratory pressure is reduced in dystrophic (mdx) mice

Neuromuscular coupling (NMC) is a recognised clinical index of inspiratory muscle function which reflects the efficiency of conversion of neural activation to inspiratory pressure. Duchenne muscular dystrophy (DMD) is characterised by respiratory insufficiency culminating in respiratory failure. We investigated inspiratory pressure generating capacity and electrical activation of obligatory inspiratory muscles in X-linked muscular dystrophy ( mdx) mice, to evaluate NMC of diaphragm, external intercostal and parasternal intercostal to inspiratory pressure across a range of behaviours in early established to late progressive disease.In urethane anaesthetised mice (1.7 g/kg i.p.), inspiratory pressure was recorded via a pressure transducer positioned in the thoracic oesophagus. Diaphragm EMG activity was recorded using needle electrodes. Studies were performed in male wildtype (WT) and mdx mice at 4, 8, 12 and 16 months old. Recordings were made at baseline and during sustained tracheal occlusion to task failure, defined as an inability to sustain peak pressure. Peak pressure was determined from the average of five successive peak efforts at the maximum response. The corresponding peak inspiratory EMG activities were determined. Two factor (age x genotype) analysis of variance was performed.Obligatory muscle EMG activities were significantly lower in mdx mice from 4 months of age. Peak inspiratory pressure was significantly greater in mdx at 4 months of age. At 8 months, peak inspiratory pressure was equivalent between WT and mdx followed by a significant decrease in peak inspiratory pressure in 12- and 16-month-old mdx. NMC was lower in mdx mice across the ventilatory and non-ventilatory range, emerging early in dystrophic disease.Reduced NMC of obligatory muscles to inspiratory pressure in mdx mice reveals a greater reliance on accessory muscles to support respiratory performance in dystrophic disease. Remarkably, this burden is adequately accommodated in early disease with a preserved capacity to generate peak inspiratory pressure. We reason that the loss of compensation afforded by accessory muscles to peak inspiratory pressure generation underpins the emergence of respiratory compromise in advanced disease. Our results may have implications for the understanding and treatment of DMD. Funded by Science Foundation Ireland SFI/19/6628 INSPIRE DMD. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Assessment of heart rate variability (HRV) in SN rotenone-induced lesion Parkinson's disease rat model

Parkinson’s disease (PD) is a progressive neurodegenerative disorder caused by loss of dopaminergic neurons in the substantia nigra (SN). While PD is clinically characterized by motor deficits, non-motor symptoms such as autonomic dysfunction that can lead to deficits in cardiovascular function are common in early PD. Autonomic dysfunction is an imbalance in sympathetic (SNS) and parasympathetic (PNS; vagal) tone, which directly impacts cardiovascular function and responsiveness, leading to alterations in heart rate variability (HRV). HRV is the fluctuation in time intervals between consecutive heartbeats, and reduced HRV has been linked to increased risk for cardiovascular morbidity and mortality in both cardiac and non-cardiac disorders, including those associated with PD. To gain further insight into the influence of PD on autonomic balance, we investigated measures of HRV quantified from a 20-min segment of basal ECG activity recorded in a rat model of PD generated by unilateral injection of the pesticide rotenone (ROT; n=8) into the SN; SN injection of vehicle (VEH) in a separate group of rats (n=7) served as a control. At 2-weeks after SN injection, ECG activity was recorded in urethane-anesthetized adult female Sprague-Dawley rats using needle electrodes inserted into each forepaw, RR interval data were obtained from the ECG records, and HRV was quantified using time-domain analysis to obtain SDRR and RMSSD, frequency-domain analysis to obtain spectral power in the low (LF) and high (HF) frequency bands and the LF/HF ratio, and non-linear Poincaré plot analysis to obtain SD1, SD2, and the SD1/SD2 ratio, with all data presented as mean±SE. Evaluation of mixed SNS/PNS tone measures showed that SDRR (2.89±1.09 vs 2.60±0.98 ms), relative LF power (49.9±18.9 vs 44.8±16.9% (nu)), and SD2 (4.25±1.60 vs 3.38±1.27 ms) were similar in ROT- and VEH-injected rats while evaluation of PNS tone measures showed that RMSSD (3.59±1.36 ms vs 2.00±0.75 ms) and SD1 (2.55±0.96 vs 1.42±0.53 ms) were slightly but not significantly higher in ROT-injected rats albeit relative HF power (50.1±18.9 vs 55.2±20.9% (nu)) was similar in both groups. Evaluation of sympatho-vagal balance measures showed that LF/HF ratio (1.05±0.40 vs 1.52±0.58) and SD1/SD2 ratio (0.56±0.21 vs 0.46±0.17) were similar in ROT- and VEH-injected rats albeit both measures appeared to favor slightly enhanced PNS tone in ROT-injected rats. Qualitative evaluation of Poincaré plot histogram data revealed that ROT-injected rats exhibited multiple modal clusters of beat-to-beat RR interval behaviors, suggesting that alterations in HRV are likely present. While our preliminary data show some slight alterations in HRV in ROT-injected rats, additional data are needed to improve statistical power of our comparisons as well as to better capture changes in sympatho-vagal balance and identify underlying mechanisms responsible for autonomic dysfunction in PD. Thomas Hartman Center for Parkinson's Disease Research at Stony Brook University This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

PO-05-036 PERCUTANEOUS STELLATE GANGLIA ABLATION IN THE MANAGEMENT OF VTSTORM

VT storm is a clinical emergency associated with high mortality. Neural modulation of the cardiac sympathetic chain, usually in the form of surgical sympathectomy, has shown to be effective in achieving reduction in appropriate ICD shocks and VT episodes. We hypothesised Percutaneous Stellate Ganglion Ablation (SGA) is a safe and effective alternative modality of neuromodulation in patients with VT storm. Patients with ES refractory to standard management, including sedation and mechanical ventilation, antiarrhythmic agents and beta-blockers, underwent bilateral percutaneous SGA. The ablation was performed at 2 levels - C7 and T1, bilaterally, under fluoroscopic guidance using a customized protocol. (Figure) At each site, 3 lesions were delivered sequentially at 50, 55 and 60 deg. C for 90 seconds using a COSMAN RF generator and RF needle electrode of 5cm length and 4mm active tip with ipsilateral Horner’s syndrome being the clinical end-point for successful ablation. Patients were followed up till discharge and as outpatients with periodic device interrogation There were 6 patients with refractory VT storm (4 male & 2 female) with a mean age of 56.5±5.2 years. The VT was monomorphic in 4 and polymorphic in the other 2 patients. The substrate was Ischaemic cardiomyopathy in 2, Non-ischaemic cardiomyopathy in 3 and Hypertrophic cardiomyopathy in 1 patient. The meean LVEF was 35 ± 20%. There were no periprocedural complications. Post-procedure, 2 out of the 6 patients had one episode of Non-sustained VT each in-hospital. All patients were discharged on Amiodarone and Metoprolol. The mean follow-up duration was 15± 3 months. At last follow-up all of them are alive and none of then received any shocks.. One patient had a VT at 42 days after procedUre which was terminated by device using ATP. SGA by RFA is a safe, effective, inexpensive, well-tolerated and minimally invasive procedure for neuromodulation and should be considered in drug refractory ES.

Evaluation of spatial distribution of the oxidation of glass beads simulating soil using high-voltage pulsed discharge

The spatial distribution of soil oxidation using a high-voltage pulse generator was evaluated using indigo carmine. The results showed that the amount of indigo carmine decolorization increased with increasing charging voltage and energy input. It was also found that the decolorization of indigo carmine occurred on the surface of the needle electrode, in the discharge path, and near the ground electrode. The probability of discharge penetrating soil increased with decreasing the gap length between the electrode tip and soil surface, which promoted the decolorization reactions. The amount of indigo carmine decolorization per volume decreased with increasing soil depth. When the soil depth was large, discharges reaching the ground electrode could not be confirmed. This suggests that the oxidation reaction of indigo carmine depends on a discharge that penetrates the soil.

Cytoskeletal Remodeling and Gap Junction Translocation Mediates Blood-Brain Barrier Disruption by Non-invasive Low-Voltage Pulsed Electric Fields.

High-voltage pulsed electric fields (HV-PEF) delivered with invasive needle electrodes for electroporation applications is known to induce off-target blood-brain barrier (BBB) disruption. In this study, we sought to determine the feasibility of minimally invasive PEF application to produce BBB disruption in rat brain and identify the putative mechanisms mediating the effect. We observed dose-dependent presence of Evans Blue (EB) dye in rat brain when PEF were delivered with a skull mounted electrode used for neurostimulation application. Maximum region of dye uptake was observed while using 1500V, 100 pulses, 100µs and 10Hz. Results of computational models suggested that the region of BBB disruption was occurring at thresholds of 63V/cm or higher; well below intensity levels for electroporation. In vitro experiments recapitulating this effect with human umbilical vein endothelial cells (HUVEC) demonstrated cellular alterations that underlie BBB manifests at low-voltage high-pulse conditions without affecting cell viability or proliferation. Morphological changes in HUVECs due to PEF were accompanied by disruption of actin cytoskeleton, loss of tight junction protein-ZO-1 and VE-Cadherin at cell junctions and partial translocation into the cytoplasm. Uptake of propidium iodide (PI) in PEF treated conditions is less than 1% and 2.5% of total number of cells in high voltage (HV) and low-voltage (LV) groups, respectively, implying that BBB disruption to be independent of electroporation under these conditions. 3-D microfabricated blood vessel permeability was found to increase significantly following PEF treatment and confirmed with correlative cytoskeletal changes and loss of tight junction proteins. Finally, we show that the rat brain model can be scaled to human brains with a similar effect on BBB disruption characterized by electric field strength (EFS) threshold and using a combination of two bilateral HD electrode configurations.

Electrical degradation dynamics of glass fiber-reinforced epoxy composites considering different fiber orientation

Glass fiber-reinforced epoxy composites (GFREC) have been widely used in the mechanical components of electrical and electronic devices because of its lightweight, high mechanical strength, excellent electrical insulation properties and corrosion resistance. The research on the electrical degradation dynamics of GFREC is of great significance to avoid the failure of electrical insulation system. Herein the composite samples were prepared using vacuum impregnation technique. The electrical degradation morphology and statistical characteristics (electrical tree length, width, expansion coefficient, breakdown probability and breakdown time) were discussed. The results show that the electrical tree will develop towards the fiber side and grow rapidly along the interface in GFREC. The interfacial orientation will affect the growth characteristics of electrical tree. When the angle between the glass fiber and the needle electrode is 45°, the composite material has relatively superior tree propagation resistance performance, lower breakdown probability and higher breakdown time. The effects of electric field distribution on the tree initiation and electrical degradation are discussed, which reveals the relationship between the electrical degradation and the fiber orientations. The electric field-driven tree growth (FDTG) model is used to explain the growth of trees along interfaces with different orientations from the perspective of dynamic electric field distribution.

Liquid metal enabled plant injectable electronics

Extensive efforts have been made on utilizing conductive materials to monitor plant growth states. However, traditional methods are facing difficulties as physiological signals are usually concealed within plant tissues. Here, we propose a new conceptual plant injectable electronics based on the fluidic properties and high conductivity of liquid metals, which can not only resolve the existing challenges but also endow plants with diverse electronic capabilities. Following this principle, the basic electronic components (resistors, inductors, and capacitors) are successfully fabricated by injecting liquid metal into the target sites of the living plant. Furthermore, we demonstrate typical applications derived therefrom, including highly stable electrodes, long-term working sensors, and stealthy antennae with variable characteristics. Specifically, the resulting liquid metal injectable electrodes exhibit outstanding electric signal capture capability (over 2000% improvement versus printed electrodes), and remarkable anti-interference characteristics compared to conventional rigid needle electrodes. Injectable resistance and capacitance sensors provide ever-useful ways for real-time monitoring of plant position and physiological signals. More importantly, the capacitive sensor obtained by injection gives access to information about the interior of the plant that cannot be detected from non-injectable capacitive sensors otherwise. Additionally, antennas invisible from the outside with variable characteristics are manufactured and evaluated in situ in living plants, further justifying the capability of the plant injectable electronics. The present principle suggests an unconventional strategy to combine plants and electronics, which signifies a paradigm shift and is expected to serve as a basic platform for additional investigation in plant electrophysiology, electronic plants, and plant robots.

Barley systemic bioelectrical changes detect pathogenic infection days before the first disease symptoms

Plant electrome corresponds to the emergent set of plant bioelectrical activity. The infection of plant tissues by different fungi alters this bioelectrical activity and can originate different electrical signatures, which can be used to identify the potential pathogenic agent. In this work, we evaluated the systemic variations of the electrome of barley triggered by the inoculation of Blumeria graminis and Bipolaris sorokiniana on the leaves. Therefore, approximately 50 days-old barley plants were placed within a Faraday cage under controlled conditions. A pair of needle electrodes was inserted in the culm for the recording of bioelectrical data. The plants were then inoculated with the pathogen in the last completely expanded leaf. Each pathogen was inoculated in different plants. Plants exposed to the same procedures as the inoculated ones, but without the fungi, served as controls. The electromes were recorded through 48 h, 24 h of which before the fungi inoculation or the control treatment. The bioelectrical data collected were analysed as time series through the following techniques: descriptive statistics, Bayesian change point (BCP) analysis, approximate entropy (ApEn), and autocorrelation. The results of these analyses were used as features, hence creating the dataset used in the machine learning (cluster analysis). The results indicate that the inoculation of pathogenic fungi culminated in a greater electrome variation (EV) when compared with the control (simulated inoculation). The pathogen inoculation generated peculiarities in the EV distribution for each pathogen. Therefore, the inoculation of B. graminis or B. sorokiniana created an electrical signature specific for each pathogen. This signature allows identifying the presence of pathogenic infection in the first minutes after contact with the host surface.

The Feasibility Study of Intraoperative RLN Monitoring Using Cricothyroid Membrane-Inserted Needle Electrodes During Thyroid Surgery.

This study evaluated the feasibility, stability, safety, and economy of cricothyroid membrane (CM)-inserted needle electrodes for recurrent laryngeal nerve monitoring. Parallel and controlled study. Clinical research center for thyroid diseases of Shaanxi province. A total of 64 patients in the needle electrodes group (104 recurrent laryngeal nerves [RLNs]) and 44 patients in the endotracheal tube (ETT)-based electrodes group (80 RLNs) underwent monitored thyroidectomy. The evoked electromyography (EMG) signals detected by the 2 electrodes were recorded and analyzed. The changes in EMG during Berry's ligament traction and tracheal displacement were compared. All patients underwent preoperative and postoperative laryngoscopy within 1 week. Both electrodes successfully recorded typical evoked laryngeal EMG waveforms from RLNs. The needle electrodes recorded relatively higher amplitudes and similar latencies compared to ETT-based electrodes. The evoked EMG signals attributed to needle electrodes could accurately predict the function of RLNs with 100% sensitivity and specificity. The reduction in the recorded amplitudes attributed to needle electrodes was higher than that observed with ETT-based electrodes during Berry's ligament traction or trachea displacement, whereas a similar increase in the latencies was recorded in the 2 groups. Particularly, Berry's ligament traction was more likely to lead to EMG amplitude reduction and latency prolongation. The needle electrodes group recorded 2 cases of minor bleeding on the CM. The needle electrodes were more cost-effective than ETT-based electrodes. The CM-inserted needle electrodes are feasible, stable, safe, and economical for RLN monitoring, and they provide an alternative novel intraoperative neural monitoring format for thyroid surgeons.

THE INFLUENCE OF PHYSICAL FACTORS ON THE GROWTH OF BACTERIA-ANTAGONIST BACILLUS SUBTILIS BIM B-760 D

The influence of electric current and electromagnetic radiation on the growth and antimicrobial activity of bacteria B. subtilis BIM B-760 D - the basis of the biopesticide "Bactaven C" was studied. It was determined that the use of inoculum treated with an alternating current of 16 mA and frequency 17 Hz has enabled to obtain a 2-day culture of B. subtilis BIM B-760 D with a titer of CFU and spores 2.4 – 2.7 times higher compared to the variant without electrical stimulation. Exposure of the seed material for 30 minutes in the electromagnetic field of a Tesla transformer (frequency 490 kHz) with a multi–needle electrode promoted 1.9 – 2.0 times increase in the titer of spores, CFU and 12 % higher antifungal activity by 48 h of culture.

Evaluation of space charge distribution under a divergent electric field by combining experiment and simulation

Under divergent electric fields, space charge is locally accumulated and controls the initiation and evolution of insulation degradation phenomena, such as electrical trees and partial discharge. The space charge profiles provide crucial information for evaluating the insulation performance. However, the existing space charge measurement methods are not directly applicable under divergent electric fields. In this paper, a method combining experiment and simulation is proposed to evaluate the space charge distribution around a needle electrode. An experimental system is established, and the acoustic waves are measured with a hydrophone placed on the symmetric axis. In order to obtain the space charge distribution, the space charge injection process is simulated using the bipolar charge transport model to reduce the freedom of the distribution. Then, calculations are made for the acoustic waves produced by the simulated space charge distributions. Using the signals without the contribution of internal charge, a correspondence between the experiment and simulation is established. For each experimental signal, the matched calculated signal is obtained using the zero-crossing time as a reference. A perfect match between them is presented after the amplitude compensation, which indicates that the space charge distribution in the experiment is identical to that in the simulation model.