Electrode Position Research Articles

Magnetic Manipulation of Locomotive Liquid Electrodes for Wireless Active Cardiac Monitoring.

For electrocardiogram (ECG) detection, the position of conventional patch-type electrodes based on solid-state metals are difficult to manipulate after attachment and also can lead to poor interface with stretchable, rough skin surfaces. Herein, we present a liquid form of ECG electrodes that can be magnetically reconfigured on human skin by providing its conformal interfacing. These electrodes consist of biocompatible liquid-metal droplets where magnetic particles are homogeneously dispersed, and their conformal contact with skin can yield significantly low impedance as well as high signal-to-noise ratio of ECG peaks. These electrodes are also capable of complex motions such as linear movements, splitting, and merging under external magnetic fields. Furthermore, magnetic manipulation of each electrode position on human skin enables precise monitoring of ECG signals with the change in ECG vectors. The integration of liquid-state electrodes with electronic circuitry demonstrates wireless and continuous ECG monitoring while magnetically moving this entire system on human skin.

ID: 212051 EM Exposure During Non-Invasive Brain Stimulation Applications: Impact of Uncertainties on Treatment Relevant Metrics

Performance and safety of non-invasive brain stimulation (NIBS) techniques (e.g., transcranial electric stimulation (tES) or temporal interference stimulation (TIS)) rely on the precise delivery of stimulation dose (typically electric (E-)field related quantities) to targets. The assessment of uncertainty associated with electromagnetic (EM) dose calculated by finite-element method (FEM) simulations using detailed anatomical human head models to optimize stimulation parameters (e.g., electrode positions, current intensities) and predict safety and performance metrics is therefore essential. We systematically investigated the impact of experimental and modelling sources of uncertainty/variability on tES exposure and exposure-derived quantities (maximum amplitude modulation for TIS, focality of stimulation, etc.).

Localization of the gracilis muscle motor points - key considerations for botulinum neurotoxin injection and electrical stimulation.

Muscle motor points are considered the best sites for electrode positioning in electrical stimulation and, by some researchers, for botulinum neurotoxin injections. The aim of this study is to locate the motor points in the gracilis muscle to improve muscle function maintenance and treatment of spasticity. Ninety-three gracilis muscles (49 right, 44 left), fixed in 10% formalin solution, were subjected to the research. All nerve branches running towards the muscle were precisely traced to each motor point. Specific measurements were collected. The gracilis muscle presents multiple motor points (median of 12), all of which were localized on the deep (lateral) side of the muscle belly. Generally, motor points of this muscle were spread between 15% - 40% of the reference line length. Our findings may help clinicians identify appropriate locations for electrode placement during electrical stimulation of the gracilis muscle; they also deepen our understanding of the correlation between motor points and motor end plates and improve the application of botulinum neurotoxin injections.

Very high-power short-duration pulmonary vein isolation combined with anterior chest position of dispersive electrodes

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Pulmonary vein isolation (PVI) is a cornerstone management of atrial fibrillation (AF). Very high-power short-duration (vHPSD) radiofrequency catheter ablation (RFCA) can accelerate PVI procedure. Recently, special attention has been paid to the position of dispersive electrodes (DE) for optimization of RFCA application. However, these two methods have not yet been combined in the setting of PVI. Purpose To determine feasibility, safety, efficacy, and overall performance of vHPSD PVI with anterior chest position of DE. Methods Consecutive patients undergoing vHPSD PVI using flexible-tip catheter and anterior position of DE were included in the study. vHPSD protocol consisted of 70W RFCA applications lasting 4s. If needed, RFCA applications were extended using 50W until R-positive unipolar signal modification and/or until impedance drop ≥10% from baseline was achieved or were terminated in case of steam-pop occurrence. Demographical, clinical, procedural and follow-up data were collected. Results A total number of 43 patients (25 males, age 61±14years) were included in the study. 34 patients had paroxysmal AF (parox-AF group) and 9 patients had persistent AF (pers-AF group). Mean procedure time was 61±7min, mean RFCA time was 685±204s. All PVs were successfully isolated. Audible steam pops without sequele occurred in 6 (14%) cases. Major complications included one TIA without sequele. During follow-up 33 (77%) patients remained AF-free: 26 (76%) in parox-AF group vs 7 (78%) in pers-AF group (log rank p=0.0166). No atrioesophageal fistula or evidence of esophageal injury occurred. Conclusions Anterior chest position of DE combined with vHPSD approach for PVI is feasible, appears safe and effective. More data on possible protective properties against atrioesophageal fistula occurrence using the presented approach is warranted.

Epicardial versus endocardial pacing in cardiac resynchronization therapy

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Norwegian Research Council. Background/Introduction The timing of left ventricular pressure rise (Td) relative to QRS-onset is associated with dispersion of regional work distribution and prolongs with dyssynchrony and dyssynergistic contractions. Td is short in normal conduction and shortening of Td can be achieved with effective biventricular pacing (BIVP). The effect of endocardial compared to epicardial pacing on Td is unknown and could be important for the interpretation of Td when different pacing strategies are utilized for CRT. Purpose We wanted to analyze the measurement from QRS-onset to onset of LV pressure rise identified as the peak double derivative of LV pressure rise (Onset of Synergy, OoS) and to the peak pressure rise (Td), and test the effects of cardiac resynchronization therapy with endocardial vs epicardial pacing electrodes in a large animal model of LBBB. Methods 5 mongrel dogs were included in the study and handled according to ethics committee approved protocol/GLP. Pacing electrodes were placed epicardial on the left ventricular (LVepi) and right ventricular (RVepi) free wall, and endocardial electrodes were positioned at the right ventricular septum (RVsept) and in the LV endocardial free wall (LVendo). The atrial electrode was placed on the left atrial appendage. Pressure was measured with a Micro-tip pressure sensor (Millar Inc.) in the LV and sampled at 1000Hz. LBBB was created with a retrograde placed 7F standard ablation catheter and confirmed by surface ECG and four endocardial electrodes. Td was measured from 10 consecutive beats. Mixed models were utilized for the repeated measurements. Results Td was measured to 115±2ms at baseline in LBBB. Td decreased by 5ms from RVepi (114±3ms) to RVendo (109±3ms) regardless of LV electrode position. We then compared the effects of using LV endocardial and epicardial pacing in CRT and found that Td was 6ms higher (p<0.01) in LVepi (115±3ms) vs LVendo (109±3ms) regardless of RV electrode position. The interaction between RV RV and LV revealed that RVepi/LVendo (105±3ms) was significant shorter than RVendo/LVendo (110±3ms, p0.01) and RVepi/LVepi (115±3ms, p<0.01). OoS with RVepi/LVendo was 71±2ms, and a significant relationship between OoS and Td were found (R=0.62, p<0.01) to indicate that the myocardial contraction is affected by pacing already at 71ms after QRS-onset early during the pre-ejection period. Conclusion(s) In this study we demonstrate how endocardial and epicardial pacing applied with CRT may affect contraction patterns of the heart differently. The different effects from pacing can be measured as early as 71ms after QRS-onset. Shortening of Td occurs to a larger extent with pacing from the endocardial LV and epicardial RV, while pacing at two endocardial sites did not result in synergistic effects on Td. This may indicate that there might be an interaction between endocardial pacing sites when applied in combination.

Transcranial direct current stimulation alters the process of reward processing in children with ADHD: Evidence from cognitive modeling

BackgroundThe ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) are the neural underpinnings of reward processing, which is impaired in individuals with attention deficit hyperactivity disorder (ADHD). In the present study, we aimed to explore the impact of the vmPFC and the dlPFC regulation on reward processing. MethodsTwenty-six children with ADHD performed the balloon analogue risk-taking task (BART) and chocolate delay discounting task (CDDT) during five different sessions of transcranial direct current stimulation (tDCS), separated by a one-week interval: anodal left dlPFC/cathodal right vmPFC, the reversed electrode positioning, anodal left dlPFC stimulation with extracranial return electrode, anodal right vmPFC stimulation with extracranial return electrodes, and sham stimulation. Four-parameter and constant-sensitivity models were used to model the data. ResultsIn the BART, anodal dlPFC/cathodal vmPFC stimulation facilitated conservative decision making, anodal tDCS over dlPFC with extracranial return electrode increased positive beliefs about the explosion of a balloon, and anodal vmPFC/cathodal dlPFC stimulation reduced ongoing learning in the process of decision making. In the CDDT, anodal vmPFC stimulation with extracranial return electrode decreased impatience in the process of the task. ConclusionThese results suggest a role of the left dlPFC and right vmPFC in the outcome of decision making and the process of risky decision making and delay discounting.

Imbalance of active ions through segmented electrodes: Mass transfer characteristics of vanadium redox flow batteries

The mass transfer that occurs at the interface between the porous electrode and electrolyte is important because it is closely related to the electrochemical performance of batteries. In general, as the materials used for electrodes have irregularly connected microscale pores, various methods exist to predict the permeation path of the electrolyte between the inlet and outlet. In this study, we investigate the use of segmented cells to experimentally visualize the mass transfer properties that occur during electrochemical reactions in porous electrodes. In this work, the measured voltages are quantitatively compared with the voltage deviation for each electrode position for a segment cell that is divided into 25 active areas, each measuring 25 cm2. As a result, the electrochemical reaction for each charge/discharge process caused by the physical and electrochemical properties of the VRFB electrolyte showed a relatively uniform reactivity during the charging process. The strategy of enhancing the supply of active ions by increasing the flow rate does not contribute to reducing the voltage difference inside the active region. When the current density is increased by 100%, the rate of increase of the voltage deviation by the electrode position is 70% and 140% in the charging and discharging process, respectively. Furthermore, in the DoD 100% discharge stage based on the cell voltage, the voltage difference is approximately 6.3 times higher than the average voltage deviation in the SoC 0–100% and DoD 0–90% stages. This paper presents a strategy to ensure stable operation during the system charge/discharge process by measuring the voltage at each position of the porous electrode used as an electrode.

Optimization of electrode positions for equalizing local spatial performance of a tomographic tactile sensor.

A tomographic tactile sensor based on the contact resistance of conductors is a high sensitive pressure distribution imaging method and has advantages on the flexibility and scalability of device. While the addition of internal electrodes improves the sensor's spatial resolution, there still remain variations in resolution that depend on the contact position. In this study, we propose an optimization algorithm for electrode positions that improves entire spatial resolution by compensating for local variations in spatial resolution. Simulation results for sensors with 16 or 64 electrodes show that the proposed algorithm improves performance to 0.81 times and 0.93 times in the worst spatial resolution region of the detection area compared to equally spaced grid electrodes. The proposed methods enable tomographic tactile sensors to detect contact pressure distribution more accurately than the conventional methods, providing high-performance tactile sensing for many applications.

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth.

Reliable determination of cochlear implant electrode positions shows promise for clinical applications, including anatomy-based fitting of audio processors or monitoring of electrode migration during follow-up. Currently, electrode positioning is measured using radiography. The primary objective of this study is to extend and validate an impedance-based method for estimating electrode insertion depths, which could serve as a radiation-free and cost-effective alternative to radiography. The secondary objective is to evaluate the reliability of the estimation method in the postoperative follow-up over several months. The ground truth insertion depths were measured from postoperative computed tomography scans obtained from the records of 56 cases with an identical lateral wall electrode array. For each of these cases, impedance telemetry records were retrieved starting from the day of implantation up to a maximum observation period of 60 mo. Based on these recordings, the linear and angular electrode insertion depths were estimated using a phenomenological model. The estimates obtained were compared with the ground truth values to calculate the accuracy of the model. Analysis of the long-term recordings using a linear mixed-effects model showed that postoperative tissue resistances remained stable throughout the follow-up period, except for the two most basal electrodes, which increased significantly over time (electrode 11: ~10 Ω/year, electrode 12: ~30 Ω/year). Inferred phenomenological models from early and late impedance telemetry recordings were not different. The insertion depth of all electrodes was estimated with an absolute error of 0.9 mm ± 0.6 mm or 22° ± 18° angle (mean ± SD). Insertion depth estimations of the model were reliable over time when comparing two postoperative computed tomography scans of the same ear. Our results confirm that the impedance-based position estimation method can be applied to postoperative impedance telemetry recordings. Future work needs to address extracochlear electrode detection to increase the performance of the method.

Application of intraoperative CT-assisted positioning in difficult cases of cochlear implantation

Objective:To report the experience of using CT-guided cochlear implant surgery in difficult cases such as severe inner ear deformities and anatomical abnormalities, and to discuss the application value of intraoperative CT-assisted localization in difficult cases of cochlear implant surgery. Methods:Retrospectively analyzed the clinical data of 23 cases of difficult cochlear implant surgery cases completed by our team with the assistance of intraoperative CT, and collected their medical data, including preoperative imaging manifestations, surgical conditions, and intraoperative imaging images for evaluation. Results:During the study period, 23 difficult cases（27 ears） underwent cochlear implantation under the guidance of intraoperative CT, and 4 cases were bilaterally implanted. Including 6 cases of incomplete segmentation type Ⅰ（IP-Ⅰ）, 1 case of incomplete segmentation type Ⅱ（IP-Ⅱ）, 10 cases of incomplete segmentation type Ⅲ（IP-Ⅲ）, 3 cases of common cavity deformity（CC） and 3 cases of cochlear ossification after meningitis. Facial nerve anatomy was abnormal in 9 cases, cerebrospinal fluid "blowout" was serious in 14 cases, electrode position was abnormal in 3 cases requiring intraoperative adjustment of electrode position, anatomical difficulties required intraoperative CT to assist in finding anatomical landmarks in 2 cases, and electrodes were not fully implanted in 3 cases. Conclusion:When faced with difficult cases with challenging and complex temporal bone anatomy, intraoperative CT can accurately evaluate the electrode position and provide intraoperative anatomical details, allowing immediate adjustment of the electrode position if necessary, providing safety guarantee for difficult cases of cochlear implant surgery and ensure accurate implantation of electrodes.

Dynamics Combined With Hill Model for Functional Electrical Stimulation Ankle Angle Prediction.

Musculoskeletal models play an essential role in ankle rehabilitation research. The majority of the existing models have established the relationship between EMG and joint torque. However, EMG signal acquisition requires higher clinical conditions, such as sensitivity to external circumstances, motion artifacts and electrode position. To solve the nonlinear and time-varying nature of joint movement, a Functional Electrical Stimulation (FES) model was proposed in this study to simulate the whole process of ankle dorsiflexion. The model is combined with muscle contraction dynamics based on Hill model and ankle inverse dynamics to connect FES parameters, torques, and ankle angles. In addition, the extended Kalman filter (EKF) algorithm was applied to identify the unknown parameters of the model. Model validation experiment was performed by acquiring the actual data of healthy volunteers. Results showed that the root mean square error (RMSE) and normalized root mean square error (NRMSE) of this model were 11.93%±0.53% and 1.39°±0.26°, respectively, which means it can effectively predict the output variation of ankle joint angle while changing electrical stimulation parameters. Therefore, the proposed mode is essential for developing closed-loop feedback control of electrical stimulation and has the potential to help patients to conduct rehabilitation training.

Investigation of Delay Jitter of Avalanche GaAs PCSS for Triggering High-Voltage Gas Switch

The delay jitter characteristics of gallium arsenide (GaAs) photoconductive semiconductor switches (PCSSs) triggered in avalanche mode were experimentally investigated under dc bias. In the dark-state measurement, the PCSS was tested under a 40-kV bias voltage to verify its withstanding voltage and reliability. In the ON-state measurement, the delay jitter time of PCSS at different triggering positions was measured. The experimental results showed that the shortest delay jitter time was obtained when the laser was applied to the middle position of the cathode electrode. To evaluate the long-time stability, the delay-jitter time was recorded after continuous shots. It shows an ascending trend in delay jitter time with the increase in operating shots. The degeneration of the delay jitter time of the PCSS was mainly attributed to the device damage, including electrode ablation and filament current ablation, which was verified by the analysis of scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). Furthermore, a bipolar high-voltage gas switch integrated with PCSSs was successfully triggered by a low-energy fiber laser.

PO-03-013 ELECTRO-ANATOMICAL CHARACTERIZATION OF LEADLESS LEFT BUNDLE BRANCH AREA PACING

Leadless left ventricular (LV) endocardial pacing with the WiSE-CRT System (EBR Systems Inc) is an emerging treatment in the field of cardiac resynchronization therapy (CRT). Whilst the system was designed to provide LV lateral wall endocardial pacing, modifications to the implant technique have recently enabled positioning of the pacing electrode in the LV septum to perform left bundle branch area pacing (LBBAP). The electrical performance of leadless LBBAP is yet to be determined. We aimed to electro-anatomically characterize the biventricular (BiV) activation patterns of leadless LBBAP in patients with heart failure receiving CRT with the WiSE-CRT system. Four patients with the WiSE-CRT System, all with the pacing electrode located in the LV septum, underwent an electrocardiographic imaging (ECGi) study. The following pacing modalities were tested: Right Ventricular Pacing (RVP); BiV pacing (RVP + LV); LV only; and LV only with an electrically optimised atrioventricular delay (AVD) in patients with sinus rhythm. Reconstructed epicardial electrograms from ECGi were used to calculate LV activation time (LVAT-90), RV activation time (RVAT-90), BiV activation time (BIVAT-90), LV dyssynchrony index (LVDI), and BiV dyssynchrony index (BIVDI). For each metric, the percentage improvement compared to RVP was calculated. At the optimal pacing modality, CRT using leadless LV septal endocardial pacing achieved significant improvements in: LVAT-90 (33.9% ± 24.6, p=0.01); RVAT-90 (51.7% ± 24.1, p=0.003); BiVAT-90 (31.3% ± 30.8, p=0.03) and LV-DI (39.7% ± 39.7, p=0.03), see figure. There was individual variability in optimal pacing modality (see table). For 2 patients with sinus rhythm (SR) and left bundle branch block (LBBB), the optimal modality was LV only pacing with optimised AVD. Two patients had AF and complete heart block (CHB). For these cases, BiV pacing achieved the optimal results for 1 patient, whereas LV only pacing performed best for the other. Leadless LV LBBAP endocardial pacing significantly improves ECGi-derived activation metrics at the optimal pacing modality in both patients in SR and AF. For those with underlying SR and LBBB, LBBAP with AVD optimisation may be the optimal modality as this allows RV activation via native conduction. As each patient required a different protocol to achieve the optimal result, personalisation may be important for LV LBBAP.Tabled 1Optimized pacing setting by activation metric (PO-03-013)PatientUnderlying RhythmBiVAT-90LVAT-90RVAT-90LV-DIBiV-DI1AF, CHBLV onlyLV onlyLV onlyLV onlyLV only2SR, LBBBLV with optimized AVD 80msLV with optimized AVD 100msLV with optimized AVD 130msLV with optimized AVD 80msLV with optimized AVD 100ms3AF, CHBBiVLV onlyBiVLV onlyBiV4AF, LBBBLV only with optimized AVD 180msLV only with optimized AVD 160msLV only with optimized AVD 160msLV only with optimized AVD 160msLV only with optimized AVD 160ms Open table in a new tab

Comparison Study the Modeling of Limiting Current in the Magneto Electrodeposition of Vanadium using Neural-Wiener Model and Feed Forward Neural Network

Vanadium has long been used as a corrosion-resistant coating, including as a metal alloy for battery cathodes. However, batteries discovered with non-smooth cathode surfaces due to the fabrication process have a short battery life. So, a cathode coating stage is required via the electroplating method under the influence of a magnetic field or Magneto Electro Deposition (MED). Knowing the limiting current in MED is very important because the optimum mass transport achieves at the limiting current (iB). The smoothest and most compact electrodeposit surface will occur at this limiting current. In this study, Feed Forward Neural Network and Neural-Wiener are suggested and compared as a nonlinear modeling approach to determine the ideal limiting current because of their strong capacity to anticipate the link between input and output from experiment data. The Levenberg-Marquadt optimization technique with hidden neurons was used to evaluate and compare the modeling capabilities of two neural networks, the Feed Forward Neural Network, and the Neural Wiener. The results of this study are presented as a comparison of the Mean Square Error (MSE) values obtained from the nonlinear modeling of two artificial neural network algorithms. The algorithm that models the ideal current limiting has the lowest MSE value (iB).

Detection of A Possible Subsurface Water Seepage Using 2D Electrical Resistivity Imaging Survey at a site in Al-Khwarizmi College of Engineering, University of Baghdad, Iraq

Unknown subsurface leaking water sources and possible subsurface seepage from a sewage tank in a garden at Al-Khawarizmi engineering college, University of Baghdad, were detected in this study. The 2D electrical resistivity imaging. The ERI survey is carried out along two lines, 60m and 50m long, with an electrode spacing of 1 m, forming a cross using the Wenner-Schlumberger array configuration. Line 1 is 60m, while line 2 is 50m. Soil samples were collected from line 1 at positions of electrode 34, which shows a high resistivity value, and electrode 55, which shows low resistivity, for laboratory analysis. Robust inversion and modelling processes showed relative change and high contrast in interpreted resistivities. Soil analysis showed a general homogeneity in mineral content and sediment type. Therefore, the relatively high contrast was related to variations in water content. The low resistivity was caused due to the water seepage from the sewage tank, which was precisely located.

MODIFIED CAPACITANCE MODEL IN THE CORONA PLASMA DISCHARGE

This research calculates the modified capacitance of the electrode capacitively coupled plasma (CCP) model with a crown sharp-plane configuration. The CCP model is an electrode model similar to the principle of a capacitor in a conventional circuit but differs in the arrangement of the electrodes. In the case of a positive corona, the structure of the positions of the active electrodes is almost vertical in the air, and the part of the passive electrodes is lying horizontally under the active electrodes. The shape of the active electrode is sharp at the tip of the electrode, which will cause a high potential gradient in that area, resulting in a more significant plasma discharge in the pointed area than in the less sharp area. A current multiplier factor k is entered in the tapered region of ​​calculating the capacitance model (modified capacitance) to anticipate the difference in the plasma flow. The modified capacitance model for calculating the corona discharge's current-voltage (I-V) characteristics has proven that geometric calculations of the electrodes can also be carried out without using a physical calculation model (Maxwell's equations).

Full-field, conformal epiretinal electrode array using hydrogel and polymer hybrid technology

Shape-morphable electrode arrays can form 3D surfaces to conform to complex neural anatomy and provide consistent positioning needed for next-generation neural interfaces. Retinal prostheses need a curved interface to match the spherical eye and a coverage of several cm to restore peripheral vision. We fabricated a full-field array that can (1) cover a visual field of 57° based on electrode position and of 113° based on the substrate size; (2) fold to form a compact shape for implantation; (3) self-deploy into a curvature fitting the eye after implantation. The full-field array consists of multiple polymer layers, specifically, a sandwich structure of elastomer/polyimide-based-electrode/elastomer, coated on one side with hydrogel. Electrodeposition of high-surface-area platinum/iridium alloy significantly improved the electrical properties of the electrodes. Hydrogel over-coating reduced electrode performance, but the electrodes retained better properties than those without platinum/iridium. The full-field array was rolled into a compact shape and, once implanted into ex vivo pig eyes, restored to a 3D curved surface. The full-field retinal array provides significant coverage of the retina while allowing surgical implantation through an incision 33% of the final device diameter. The shape-changing material platform can be used with other neural interfaces that require conformability to complex neuroanatomy.

Potential and Limitations of Research Battery Cell Types for Electrochemical Data Acquisition

AbstractDeveloping new electrode materials and/or electrolytes for lithium‐ion batteries requires reliable electrochemical testing thereof. For this purpose, in academic research typically hand‐made coin‐type cells are assembled. Their advantage is a rather cheap and facile assembly, and possibility to prepare full‐cells as well as half‐cells, meaning cathode‐anode or electrode‐elemental lithium configurations. Critical parameters for testing data quality and the potential and limitations of cell tests in half‐cell configuration are discussed. Further, on the basis of a round robin test, using highly homogenous commercial electrodes, where graphite is used as anode and LiNi0.33Mn0.33Co0.33O2 (NMC111) as the cathode material, it is shown that data acquired is highly influenced by assembling parameters. Besides known variables such as the amount of electrolyte or electrode positioning, the proper height of the cell stack and the steel grade of the housing material are identified as decisive variables. Finally, it is demonstrated that under proper conditions coin cells can show a great cycle stability of >2200 cycles using 1 C as dis‐/charge rate while retaining a capacity of 80 %. This performance is close to pouch‐type cells containing the same electrodes and electrolyte, which were used as a benchmark system and showed >3500 cycles of lifetime.

Far-field potential of the compound muscle action potential as a reliable marker in amyotrophic lateral sclerosis.

Reliable neurophysiological markers in amyotrophic lateral sclerosis (ALS) are of great interest. The compound muscle action potential (CMAP) amplitude has been a conventional marker, although it is greatly influenced by the electrode position. We propose the far-field potential of the CMAP (FFP-CMAP) as a new neurophysiological marker in ALS. Patients with ALS and age-matched healthy controls were enrolled. We used a proximal reference (pref) in addition to the conventional distal reference (dref). Routine CMAP was recorded from the belly-dref lead and FFP-CMAP from the dref-pref lead for the ulnar and tibial nerves. Multiple point stimulation motor unit number estimation (MUNE) was also examined in the ulnar nerve. Inter-rater reproducibility was evaluated by two examiners, and some patients were followed up every 3 mo for 1 y. We tested 17 patients with ALS and 10 controls. The amplitudes of routine CMAP and FFP-CMAP in the ulnar and tibial nerves, and hypothenar MUNE value in the ulnar nerve were significantly decreased in ALS compared to controls. Ulnar FFP-CMAP achieved the highest inter-rater intraclass correlation coefficient (ICC) value (0.942) when compared with routine CMAP (0.880) and MUNE (0.839). The tibial FFP-CMAP had a higher ICC value (0.986) than the routine CMAP (0.697). In this way, the FFP-CMAP showed high inter-rater reproducibility because its shape was not much influenced by the electrode position. During 1-y follow-up, decline of CMAP, FFP, and MUNE showed significant correlations with the Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised (ALSFRS-R). The FFP-CMAP shows promise as a reliable marker for ALS.

Synthesis of Carbon Nanotubes Using Modified Hummers Method for Cathode Electrodes in Dye-Sensitized Solar Cell

In this research, carbon nanotubes (CNTs) is prepared through the Hummers method with a slight change in some of the work steps, thus, a new method has been created for preparing carbon nanotubes which is similar to the original Hummers method that is used to prepare graphene oxide. Then, the suspension carbon nanotubes is transferred to a simple electrode position platform consisting of two electrodes and the cell body for the coating and reduction of the carbon nanotubes on ITO glass which represents the cathode electrode while platinum represents the anode electrode. The deposited layer of carbon nanotubes is examined through the scanning electron microscope technique (SEM), and the images throughout the research show the formation of carbon nanotubes. In the second part of the research, a dye-sensitized solar cell (DSSC) is prepared to utilize carbon nanotube as the cathode electrode, titanium oxide nanoparticles as the anode electrode by using a natural dye (pomegranate dye). The assembled dye-sensitized solar cell (DSSC) is tested by two electrodes potentiostat using Xenon light source and all parameters are established; Vocp, Imax, Vmax, Isc and calculated full factor and conversion efficiency.