Electrical Threshold Research Articles

CVD Encapsulation of Laser-Graphitized Electrodes in Diamond Electro-Optical Devices

Conductive graphitized grooves on the dielectric surface of diamond have been created by KrF excimer laser radiation. The advantages of such a circuit board in high-field applications is rather limited because the crystal surface has a relatively low electrical breakdown threshold. To increase the electrical strength, a method of encapsulating surface conductive graphitized structures by chemical vapor deposition of an epitaxial diamond layer has been proposed and realized. The quality of the growth diamond is proved by Raman spectroscopy. A comparative study of the electrical resistivity of graphitized wires and the breakdown fields between them before and after diamond growth was carried out. The proposed technique is crucial for diamond-based high-field electro-optical devices, such as THz photoconductive emitters.

The forgotten method? Pulsed electric field thresholds from the perspective of texture analysis

Pulsed electric field (PEF) technology has found applications in various industrial food sectors, including the potato industry, winemaking, biorefinery, and juice extraction, among others. The practical implementation of PEF technology in the food industry is however still hindered by several challenges. The detection and quantification of PEF effects are complex due to the variable characteristics and properties of raw materials, including cellular composition, structural organization, textural properties, and tissue porosity. Moreover, the PEF treatment parameters (e.g., pulse amplitude, duration, shape, rate), and process parameters (e.g., temperature, pH, medium conductivity) further complicate the optimization of PEF protocols, requiring a case-by-case approach. Knowledge of treated material properties and their functional dependence on PEF is a crucial prerequisite to informed, intelligent design of treatment protocols. We present an experimental study designed to gain insights into the mechanism behind the changes in textural properties induced by PEF in both plant and animal tissues. These changes in texture are then compared with findings from our previous study on electrical impedance, to highlight how different methods of detection of PEF-induced changes in tissue can yield vastly different results based on the method of analysis used depending on tissue properties. Furthermore, texture analysis unveiled the less-explored effects of PEF treatment on electroosmosis phenomena in both plant and animal tissues. We provide a comparative analysis between plant and animal tissues to elucidate the differences in deformation resulting from PEF treatment. We thus demonstrate how important it is, be it in the development phase or for process control during industrial operation, to choose an appropriate method of characterising PEF-induced changes in tissue to avoid under- or overtreatment.

Examining the design characteristics of a dual-material gate all-around tunnel FET for use in biosensing applications

Abstract An inventive analytical model for a dual material gate-all-around tunnel FET with possible applications in biosensors is described in this study. The semiconductor device considered in this study has a gate-all-around configuration built with two distinct materials. Short-channel effects are avoided with the help of the surrounding gate to achieve flexibility. A breakthrough dual-material design with a nanocavity has been developed to render it viable for biosensing applications. To figure out Poisson’s equation and to derive its surface potential, the Finite Differentiation Method is used in this work. The electric field, subthreshold swing, drain current, and threshold voltage of the suggested structure are then determined using this potential. Furthermore, the device’s biosensor sensitivity is examined and the results are verified by two-dimensional TCAD simulations.

Matching Low Viscosity with Enhanced Conductivity in Vat Photopolymerization 3D Printing: Disparity in the Electric and Rheological Percolation Thresholds of Carbon-Based Nanofillers Is Controlled by the Matrix Type and Filler Dispersion

Matching Low Viscosity with Enhanced Conductivity in Vat Photopolymerization 3D Printing: Disparity in the Electric and Rheological Percolation Thresholds of Carbon-Based Nanofillers Is Controlled by the Matrix Type and Filler Dispersion

Liver-tumor mimics as a potential translational framework for planning and testing irreversible electroporation with multiple electrodes.

Irreversible electroporation (IRE) has emerged as an appealing non-ionizing, non-thermal ablation therapy, independent of antineoplastic drugs. Limited but successful outcomes in IRE conducted in vivo, in small focal hepatocellular carcinomas (HCC), have been reported. Nonetheless, the electric parameters of IRE are usually delivered in an unplanned manner. This work investigates the integration of computational modeling to hydrogels mimicking the HCC microenvironment, as a powerful framework to: circumvent ethical concerns of in vivo experimentation; safely tune the electric parameters reaching the IRE electric field threshold; and propel the translation of IRE as a routine clinical alternative to the treatment of HCC. Therefore, a parametric study served to evaluate the effects of the pulse amplitude, the number of pulses and electrodes, the treatment time, the hydrogel-tumor size, and the cell type. The ablation extent was surveyed by confocal microscopy and magnetic resonance imaging (MRI) in cylindrical and realistic tumor-shaped hydrogels, respectively. A large ablation (70%-100%) was verified in all constructs.

Development of a 3 MV coaxial peaking capacitor for large-scale electromagnetic pulse simulator.

Coaxial peaking capacitor is a key component in high-altitude electromagnetic pulse (EMP) simulators with fast front pulse output. It poses significant technical and engineering challenges in limiting radiation field amplitude and test space. This paper presents the design and testing of a 180 pF, 3 MV coaxial peaking capacitor with improved insulation performance. In the insulation design, the length of the dielectric film is extended to reduce the background electric field on the flashover path. The electric field threshold obtained from image diagnosis is used as a reference. During capacitor testing, the insulation characteristics are diagnosed using both direct and indirect methods. The voltage measured by a D-dot probe, the output waveform of the Marx generator in the primary source, and the radiation field waveform are analyzed to understand the flashover characteristics of the capacitor and to improve the reliability of the test results. The experimental results demonstrate that the peaking capacitor can operate stably at 3.0 MV. If flashover occurring on the dropping edge of the pulse is permitted, the operating voltage can be greater than 3.7 MV without significantly affecting the radiation field waveform. The analysis on the surface flashover morphology of the peaking capacitor reveals that the flashover mainly occurs at the dropping edge of the capacitor's waveform, indicating that the damage to the film is not serious. This research significantly increases the working voltage of coaxial peaking capacitors and contributes to the development of high-altitude EMP simulation technology.

Enhanced TC in SrRuO3/DyScO3(110) thin films with high residual resistivity ratio

Epitaxial untwinned SrRuO3 thin films were grown on (110)-oriented DyScO3 substrates by molecular-beam epitaxy. We report an exceptional sample with a residual resistivity ratio (RRR), ρ [300 K]/ρ [4 K] of 205 and a ferromagnetic Curie temperature, TC, of 168.3 K. We compare the properties of this sample to other SrRuO3 films grown on DyScO3(110) with RRRs ranging from 8.8 to 205, and also compare it to the best reported bulk single crystal of SrRuO3. We determine that SrRuO3 thin films grown on DyScO3(110) have an enhanced TC as long as the RRR of the thin film is above a minimum electrical quality threshold. This RRR threshold is about 20 for SrRuO3. Films with lower RRR exhibit TCs that are significantly depressed from the intrinsic strain-enhanced value.

Creating Placebo Nonresponders in the Lab

Conditioning and expectation are known to be the main mechanisms of placebo analgesia. They may operate together, so that expectations may be enhanced by a conditioning procedure. Although most of the studies have tried to potentiate expectations through conditioning in order to generate good placebo responders, a few studies have tried to mismatch conditioning and expectations in order to investigate the subsequent administration of a placebo. In this study, we want to further investigate this mismatch. We generated incongruent associations during a conditioning procedure in which the study participants did not get what they expected. In fact, although the participants received verbal instructions of pain decrease following the administration of a placebo, we surreptitiously increased the painful electric stimulation. Two pairings of these incongruent associations (mismatch between what was expected and what was experienced) disrupted expectations of analgesia as well as the placebo effect, as assessed by measuring electric pain thresholds on the hand. The effects of mismatch conditioning on the hand extended to the contralateral arm and to a different type of pain (tourniquet), which suggests that local mismatch conditioning may affect the whole body. In all cases, expectations predicted placebo analgesia. These findings indicate that placebo nonresponders can be created in the laboratory by acting on expectations and that local effects can be generalized to other parts of the body. They also stress the importance of expectations in the therapeutic outcome, with important implications for clinical trials. PerspectiveBy using mismatch conditioning, in which study participants did not get what they expected, we reduced expectations of analgesia, and this reduction abolished placebo analgesia. This effect extended to other parts of the body and other types of pain, which indicates that placebo nonresponders can be created in the laboratory.

Reliability of quantitative sensory testing in the assessment of somatosensory function after high-frequency stimulation-induced sensitisation of central nociceptive pathways.

The high frequency stimulation (HFS) model can be used alongside quantitative sensory testing (QST) to assess the sensitisation of central nociceptive pathways. However, the validity and between-session reliability of using QST z -score profiles to measure changes in mechanical and thermal afferent pathways in the HFS model are poorly understood. In this study, 32 healthy participants underwent QST before and after HFS (5× 100 Hz trains; 10× electrical detection threshold) in the same heterotopic skin area across 2 repeated sessions. The only mechanical QST z -score profiles that demonstrated a consistent gain of function across repeated test sessions were mechanical pain threshold (MPT) and mechanical pain sensitivity (MPS), which were associated with moderate and good reliability, respectively. There was no relationship between HFS intensity and MPT and MPS z -score profiles. There was no change in low intensity, but a consistent facilitation of high-intensity pin prick stimuli in the mechanical stimulus response function across repeated test sessions. There was no change in cold pain threshold (CPT) and heat pain threshold (HPT) z -score profiles across session 1 and 2, which were associated with moderate and good reliability, respectively. There were inconsistent changes in the sensitivity to innocuous thermal QST parameters, with cool detection threshold (CDT), warm detection threshold (WDT), and thermal sensory limen (TSL) all producing poor reliability. These data suggest that HFS-induced changes in MPS z -score profiles is a reliable way to assess experimentally induced central sensitisation and associated secondary mechanical hyperalgesia in healthy participants.

Serum VEGF and CGRP Biomarkers: Relationships with Pain Intensity, Electric Pain, Pressure Pain Threshold, and Clinical Symptoms in Fibromyalgia—An Observational Study

Fibromyalgia (FM) is a multifactorial syndrome, mainly characterized by chronic widespread pain, whose physiopathology is yet to be determined. Reliable biomarkers for FM and how they are associated with the symptomatology have not yet been identified. We aimed to examine the relationships among serum vascular endothelial growth factor (VEGF) and calcitonin gene-related peptide (CGRP) levels with clinical manifestations and pain-related variables in women with FM. We conducted an observational case study with forty-seven women diagnosed with FM. Serum VEGF and CGRP levels were spectrophotometrically analyzed. We used questionnaires to measure the impact of FM and the degree of central sensitization, fatigue, and anxiety. We also assessed pain intensity, electric pain threshold and magnitude, and pressure pain threshold (PPT) in tender points. The linear regression analysis adjusting for age, menopause status, and body mass index showed that serum VEGF levels were significantly associated with the PPTs of non-dominant trapezius (β = 153.418; p = 0.033), non-dominant second metacarpal (β = 174.676; p = 0.008) and dominant tibialis anterior (β = 115.080; p = 0.049) in women with FM. We found no association between serum CGRP levels and the variables measured (p ≥ 0.152). Our results suggest that VEGF may be related to pain processing in patients with FM.

Relativistic Runaway Electron Avalanche Development Near the Electric Field Threshold in Inhomogeneous Air

AbstractRelativistic Runaway Electrons Avalanches (RREAs) development depends on the applied electric field and the environment's air density. This dependency controls the RREA exponential growth length scale. The RREA development affects the bremsstrahlung excess occurring due to the passage of charged particles through the thundercloud's electric fields, the gamma‐ray glow. We used Monte Carlo simulations to develop an empirical model showing the RREA behavior in a realistic atmospheric density profile. The new formulation shows how the density variation modulates the electron population under electric field strengths near the RREA electric field threshold. The model limits the initial RREA altitude range as a function of the electric field strength. The new model is valid between ∼0.6 and ∼18 km, covering the relevant heights to investigate the generation of ground‐detected gamma‐ray glows.

The role of arsenic in the operation of sulfur-based electrical threshold switches

Arsenic is an essential dopant in conventional silicon-based semiconductors and emerging phase-change memory (PCM), yet the detailed functional mechanism is still lacking in the latter. Here, we fabricate chalcogenide-based ovonic threshold switching (OTS) selectors, which are key units for suppressing sneak currents in 3D PCM arrays, with various As concentrations. We discovered that incorporation of As into GeS brings >100 °C increase in crystallization temperature, remarkably improving the switching repeatability and prolonging the device lifetime. These benefits arise from strengthened As-S bonds and sluggish atomic migration after As incorporation, which reduces the leakage current by more than an order of magnitude and significantly suppresses the operational voltage drift, ultimately enabling a back-end-of-line-compatible OTS selector with >12 MA/cm2 on-current, ~10 ns speed, and a lifetime approaching 1010 cycles after 450 °C annealing. These findings allow the precise performance control of GeSAs-based OTS materials for high-density 3D PCM applications.

New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models

Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias’ characteristics and significance help in development of new antiarrhythmic drugs.

Molecular dynamics simulation of the transmembrane transport process of reactive species under the synergistic effect of plasma oxidation and an electric field

Cold atmospheric pressure plasma (CAP)-assisted cancer therapy has become a popular topic in plasma biomedical research. Membrane lipid oxidation and local electric fields are two important factors in plasma–cell interactions, and the study of their synergistic effect is highly significant for optimizing the regulatory mechanism of the plasma-induced apoptosis of cancer cells. In this paper, a model of oxidized phospholipids was established, and the transmembrane process of reactive species was simulated by the classical molecular dynamics (MD) method under the conditions of oxidation and an electric field. The results showed that hydrophilic reactive oxygen species could not penetrate the membrane lipids through oxidation. The formation of electroporation provided a new channel for reactive species to penetrate the membrane, and the oxidation effect reduced the electric field threshold of membrane electroporation. Our simulation could provide theoretical support for the plasma-induced apoptosis of cancer cells at the microscopic level, provide mechanistic guidance for the practical application of plasma-induced cancer therapy, and promote the development of CAP in the field of cancer therapy.

Further evaluation of inflammatory and non-inflammatory aspects of pain in rheumatoid arthritis patients.

A high discrepancy between the number of tender and swollen joints (e.g. ΔTSJ ≥ 7) has previously been used as an indication for the presence of changes in central mechanisms in patients with moderate-to-high disease activity. In this study, we explored whether the ΔTSJ can also be used to obtain insights into the underlying pain mechanisms in patients with on average well-controlled disease activity. A 2 year retrospective analysis of routinely obtained 28-joint DAS (DAS28) components was performed on 45 patients with low inflammatory activity at the group level. All patients underwent pressure pain threshold (PPT) and electrical pain threshold (EPT) measurements and completed four self-report questionnaires [short-form 36 (SF-36v2); central sensitization inventory (CSI); generalized pain questionnaire (GPQ); and the pain catastrophizing scale (PCS)]. Patients with a ΔTSJ ≥ 3 at least once in the past 2 years showed significantly lower EPT and PPT values and higher levels of pain and disability on the SF-36v2 compared with the ΔTSJ < 3 group. Furthermore, GPQ scores were significantly higher in those with ΔTSJ ≥ 3, while CSI and PCS scores were similar. These findings suggest that in patients in the ΔTSJ ≥ 3 group, mechanisms other than inflammation (only) underlie the pain. Moreover, our findings suggest that among the multiple potential underlying psychological mechanisms, pain catastrophizing (as measured by the PCS) and psychological hypervigilance (as measured by the CSI) do not play an important role. These findings could be useful in the clinical management of the patient. Depending on the dominant mechanism underlying the (persistent) pain, patients might respond differently to treatment.

Intra- and inter-session reliability of electrical detection and pain thresholds of cutaneous and muscle primary afferents in the lower back of healthy individuals.

To advance evidence-based practice and targeted treatments of low back pain (LBP), a better pathophysiological understanding and reliable outcome measures are required. The processing of nociceptive information from deeper somatic structures (e.g., muscle, fascia) might play an essential role in the pathophysiology of LBP. In this study, we measured the intra- and inter-session reliability of electrical detection and pain thresholds of cutaneous and muscle primary afferents of the lower back. Twenty healthy participants attended two study visits separated by 27.7 ± 1.7days. To determine the location-specific electrical detection threshold (EDT) and pain threshold (EPT), needle electrodes were inserted in the epidermal layer over, and in the lumbar erector spinae muscle. Additionally, established quantitative sensory testing (QST) parameters were assessed. Reliability was determined by differences between measurements, intraclass correlation coefficients (ICC2,1), Bland-Altman plots, and standard error of measurement (SEM). Correspondence between QST parameters and electrical thresholds was assessed using Pearson's correlation. Except for cutaneous EPT, no significant (p ≤ 0.05) intra- and inter-session differences were observed. Excellent intra-session reliability was shown for cutaneous and intramuscular electrical stimulations and all QST parameters (ICC: 0.76-0.93). Inter-session reliabilities were good (ICC: 0.74-0.75) except for electrical stimulations (ICC: 0.08-0.36). Limits of agreement and SEM were higher for inter-session than intra-session. A medium to strong relationship was found between electrical and mechanical/pressure pain thresholds. In conclusion, cutaneous and intramuscular electrical stimulation will potentially close an important diagnostic gap regarding the selective examination of deep tissue afferents and provide location-specific information for the excitability of non-nociceptive and nociceptive afferents.

Detecting the effect of electric field threshold switching from high resistivity to low resistivity state in ceramic samples of the 3R-CuCrO2 phase

Ceramic samples of the CuCrO2 phase of 3R polytype with a delafossite structure were synthesized by solid-phase reactions. The obtained samples were characterized by thermogravimetric, X-ray diffraction, Mössbauer spectroscopic (on impurity 57Fe atoms) and dielectric and electrical studies. The effect of threshold electric field switching from a high-resistivity to a low-resistivity state was detected in the temperature range of 170–200 K and in electric fields E ≥ 1 kV/cm. The effect manifests itself in the form of giant resistance jumps (up to ∼ 2.6 orders of magnitude) on the temperature dependence, as well as in the form of S-shaped current-voltage characteristics displaying a region of negative differential resistivity. The interpretation of the detected switching effect is given based on the polaron conduction mechanism.

Removal of grade IV vestibular schwannomas by retrosigmoid approach: results of a cumulative series of two European centers

Introduction The aim of our study was to study the association between end-of-surgery facial nerve stimulation threshold and extent of tumor resection in case of grade IV vestibular schwannomas. Materials and methods Grade IV VSs represent a surgical challenge as a risk/benefit ratio must be considered in balancing a satisfactory extent of resection against a good postoperative functional outcome. We reviewed a cumulative series of 57 patients with large/giant VSs who were operated on by retrosigmoid approach in the period from 2008 to 2018 in two European centers, namely San Filippo Neri Hospital, Rome, Italy and Masaryk Hospital, Usti nad Labem, Czech Republic. Extent of resection, intraoperative direct electrical stimulation threshold of facial nerve and postoperative facial outcome were examined. Results Total or near-total resection was accomplished in 40 (75.5%) cases. Two groups were compared: total or near-total resection (T + NT) and subtotal resection (ST); the end-of-surgery facial nerve stimulation threshold significantly differed (T + NT: 0.24 mA, ST: 0.44 mA, p = 0.036). A critical cutoff was found at 0.2mA; values similar or inferior to this correctly predicted total or near-total resection in 86.7% of cases. Thirty (56.6%) patients had a normal postoperative facial outcome (HB1). Among the 40 patients in T + NT group, 32 (80%) retained an acceptable facial function (HB1-2). Conclusions Lower facial nerve stimulation thresholds positively predict a broader extent of resection and total or -near total resection should be accomplished in such cases. Judicious (subtotal) resection is preferred if threshold values increase while dissecting firmly adherent tumors.

Accurate damage localization and enhanced mechanical performance of self‐sensing epoxy nanocomposites using graphene platelets

AbstractRecently, there has been growing interest in the use of composites structure with self‐sensing functionalities in the aerospace, automotive, and renewable energy industries. However, the integration of sensors such as Fiber Bragg Grating or piezoelectric ceramic transducers into the composite structure can significantly reduce the structure's inherent strength. To address this issue, we present a novel approach for developing self‐sensing composites by incorporating graphene platelets (GnPs) as an electric filler into an epoxy matrix. Our method involves the uniform dispersion of GnPs in epoxy, with some GnPs connected to each other to achieve a low electrical threshold of 0.61 vol% in the resulting nanocomposites. The resulting composite film exhibits high sensitivity to tensile strains ranging from 0% to 1.8%, with gauge factors (GFs) ranging from 19 to 172. This variation in GF is due to the calibration process, which relies on the relationship between input and output data and does not require a constant factor. In addition to its high sensitivity to tensile strains, the composite film also demonstrates excellent self‐sensing performance for bending deformation. Moreover, the composite film effectively responds to impact damage evolution, making it a promising candidate for practical applications. This work represents an advancement in the development of self‐sensing nanocomposites using two‐dimensional materials, offering exceptional sensitivity and adaptability for potential future use.

Patterns, no patterns, that is the question: Quantifying users’ electric vehicle charging

Policymakers have structured legislation and set targets to increase the adoption of electric vehicles and the deployment of charging stations. As questions arise on how to expand the electric vehicle infrastructure, advanced computational models are attempting to quantify the future placement of charging stations. These models, however, do not necessarily incorporate the variability of user behavior as a subgroup of consumer behavior, as this information is not well-understood. This paper explores a state-wide network of 68 public charging stations' data representing 58,273 charging events to determine users' charging patterns. The methodological approach applied k-means clustering with Minkowski embedded distances to distinguish unique charging subgroups from 608 frequent users. The results indicate four user types: convenient (n = 319, 53%), gradual (n = 147, 24%), anxious (n = 104, 17%), and urgent (n = 38, 6%). Quantifying these users’ unique patterns supports the human variability knowledge required for more comprehensive and holistic models of electric vehicle charging station placement. More broadly, these results support the user-centric design of public charging infrastructure, which assists in reducing the electric vehicle adoption threshold in the long run and facilitating the transition to a low-carbon, sustainable transportation system.