electrode size
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J. Flodin ◽  
R. Juthberg ◽  
P. W. Ackermann

Abstract Background Neuromuscular electrical stimulation (NMES) may prevent muscle atrophy, accelerate rehabilitation and enhance blood circulation. Yet, one major drawback is that patient compliance is impeded by the discomfort experienced. It is well-known that the size and placement of electrodes affect the comfort and effect during high-intensity NMES. However, during low-intensity NMES the effects of electrode size/placement are mostly unknown. Therefore, the purpose of this study was to investigate how electrode size and pragmatic placement affect comfort and effect of low-intensity NMES in the thigh and gluteal muscles. Methods On 15 healthy participants, NMES-intensity (mA) was increased until visible muscle contraction, applied with three electrode sizes (2 × 2 cm, 5 × 5 cm, 5 × 9 cm), in three different configurations on quadriceps and hamstrings (short-transverse (ST), long-transverse (LT), longitudinal (L)) and two configurations on gluteus maximus (short-longitudinal (SL) and long-longitudinal (LL)). Current–density (mA/cm2) required for contraction was calculated for each electrode size. Comfort was assessed with a numerical rating scale (NRS, 0–10). Significance was set to p < 0.05 and values were expressed as median (inter-quartile range). Results On quadriceps the LT-placement exhibited significantly better comfort and lower current intensity than the ST- and L-placements. On hamstrings the L-placement resulted in the best comfort together with the lowest intensity. On gluteus maximus the LL-placement demonstrated better comfort and required less intensity than SL-placement. On all muscles, the 5 × 5 cm and 5 × 9 cm electrodes were significantly more comfortable and required less current–density for contraction than the 2 × 2 cm electrode. Conclusion During low-intensity NMES-treatment, an optimized electrode size and practical placement on each individual muscle of quadriceps, hamstrings and gluteals is crucial for comfort and intensity needed for muscle contraction.

2022 ◽  
Kavyakantha Remakanthakarup Sindhu ◽  
Duy Ngo ◽  
Hernando Ombao ◽  
Joffre E Olaya ◽  
Daniel W Shrey ◽  

Intracranial EEG (iEEG) plays a critical role in the treatment of neurological diseases, such as epilepsy and Parkinson's disease, as well as the development of neural prostheses and brain computer interfaces. While electrode geometries vary widely across these applications, the impact of electrode size on iEEG features and morphology is not well understood. Some insight has been gained from computer simulation studies and experiments in which signals are recorded using electrodes of different sizes concurrently in different brain regions. Here, we introduce a novel method to record from electrodes of different sizes in the exact same location by changing the size of iEEG electrodes after implantation in the brain. We first present a theoretical model and an in vitro validation of the method. We then report the results of an in vivo implementation in three human subjects with refractory epilepsy. We recorded iEEG data from three different electrode sizes and compared the amplitudes, power spectra, interchannel correlations, and signal-to-noise ratio (SNR) of interictal epileptiform discharges, i.e., epileptic spikes. We found that iEEG amplitude and power decreased as electrode size increased, while inter-channel correlation increased with electrode size. The SNR of epileptic spikes was generally highest in the smallest electrodes, but 39% of spikes had maximal SNR in medium or large electrodes. This likely depends on the precise location and spatial spread of each spike. Overall, this new method enables multi-scale measurements of electrical activity in the human brain that facilitate our understanding of neurophysiology, treatment of neurological disease, and development of novel technologies.

2021 ◽  
Vol 105 (1) ◽  
pp. 509-516
Martin Mačák ◽  
Petr Vyroubal

The presented article describes a simulation of an electrochemical reaction in a presence of a magnetic field using a custom model implemented into Ansys Fluent. The influence of electrode size and the effect of scan rate is investigated further. The results show that the magnetic field can significantly increase mixing and transport of species towards the electrode, which results in higher obtained current densities. Additionally, this method can be used to control fluid flow in microfluidic devices.

2021 ◽  
Vol 1 (11) ◽  
pp. 447-451
Rifat Abdurahman ◽  
Rahma Eliza ◽  
Agus Manggala ◽  
Aisyah Suci Ningsih ◽  
Sahrul Effendy A

Pengembangan energi terbarukan menjadi fokus perhatian saat ini penggunaan sumber energi yang ramah lingkungan dan zero emission dengan pemanfaatan air untuk prosess pembuatan hidrogen melalui proses elektrolisis. Hidrogen adalah gas ringan (lebih ringan dari udara), tidak berwarna dan tidak berbau, jika terbakar tidak menunjukkan adanya nyala dan akan menghasilkan panas yang sangat tinggi, sehingga hidrogen mempunyai potensi yang sangat besar untuk dikembangkan sebagai sumber energi alternatif. Penelitian ini bertujuan untuk menganalisa pengaruh luas penampang dan  konsentrasi larutan elektrolit dengan variasi suplai arus listrik terhadap produksi gas hidrogen dengan metode  elektrolisis. Larutan elektrolit yang digunakan adalah larutan air garam (NaCl) dengan berlandaskan pada kadar salinitas air laut.  Berdasarkan penelitian yang telah dilakukan membuktikan bahwa semakin tinggi konsentrasi larutan elektrolit , semakin besar luas penampang dan semakin tinggi arus yang disuplai maka volume gas yang dihasilkan akan semakin banyak. Hasil yang diperoleh yaitu volume gas H2 tertinggi pada konsentrasi salinitas 35 ppt , elektroda ukuran 0,5 in dan kuat arus 35 ampere sebesar 2,118693 liter gas H2 dalam waktu 120 detik. efisiensi tertinggi didapat pada ukuran elektroda 2,0 in ,salinitas 35 ppt dengan kuat arus 15 ampere nilai yang didapat 99,16% dan daya tertinggi dicapai pada 406 watt pada ukuran elektroda 2,0 in, salinitas 35 ppt pada kuat arus 35 ampere   The development of renewable energy is currently the focus of attention on the use of environmentally friendly energy sources and zero emission by utilizing water for the hydrogen production process through the electrolysis process. Hydrogen is a light gas (lighter than air), colorless and odorless, if it burns it does not show a flame and will produce very high heat, so hydrogen has enormous potential to be developed as an alternative energy source. This study aims to analyze the effect of cross-sectional area and concentration of electrolyte solution with variations in the supply of electric current to the production of hydrogen gas by electrolysis method. The electrolyte solution used is a salt water solution (NaCl) based on the salinity of seawater. Based on the research that has been done, it is proven that the higher the concentration of the electrolyte solution, the greater the cross-sectional area and the higher the current supplied, the more gas volume will be produced. The result obtained is the highest H2 gas volume at salinity concentration of 35 ppt, electrode size of 0.5 inchi and current strength of 35 ampere of 2.118693 liters of H2 gas in 120 seconds. the highest efficiency is obtained at the electrode size of 2.0 inchi ,salinity 35 ppt with a current strength of 15 ampere the value obtained 99.16% and the highest power achieved at 406 Watts at the electrode size of 2.0 inchi, salinity 35 ppt at the current strength of 35 ampere

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7322
Andrea Merlo ◽  
Maria Chiara Bò ◽  
Isabella Campanini

The brachioradialis muscle (BRD) is one of the main elbow flexors and is often assessed by surface electromyography (sEMG) in physiology, clinical, sports, ergonomics, and bioengineering applications. The reliability of the sEMG measurement strongly relies on the characteristics of the detection system used, because of possible crosstalk from the surrounding forearm muscles. We conducted a scoping review of the main databases to explore available guidelines of electrode placement on BRD and to map the electrode configurations used and authors’ awareness on the issues of crosstalk. One hundred and thirty-four studies were included in the review. The crosstalk was mentioned in 29 studies, although two studies only were specifically designed to assess it. One hundred and six studies (79%) did not even address the issue by generically placing the sensors above BRD, usually choosing large disposable ECG electrodes. The analysis of the literature highlights a general lack of awareness on the issues of crosstalk and the need for adequate training in the sEMG field. Three guidelines were found, whose recommendations have been compared and summarized to promote reliability in further studies. In particular, it is crucial to use miniaturized electrodes placed on a specific area over the muscle, especially when BRD activity is recorded for clinical applications.

2021 ◽  
pp. 1-13
Adam Z. Gardi ◽  
Amanda K. Vogel ◽  
Aastha K. Dharia ◽  
Chandramouli Krishnan

Background: There is a growing concern among the scientific community that the effects of transcranial direct current stimulation (tDCS) are highly variable across studies. The use of different tDCS devices and electrode sizes may contribute to this variability; however, this issue has not been verified experimentally. Objective: To evaluate the effects of tDCS device and electrode size on quadriceps motor cortical excitability. Methods: The effect of tDCS device and electrode size on quadriceps motor cortical excitability was quantified across a range of TMS intensities using a novel evoked torque approach that has been previously shown to be highly reliable. In experiment 1, anodal tDCS-induced excitability changes were measured in twenty individuals using two devices (Empi and Soterix) on two separate days. In experiment 2, anodal tDCS-induced excitability changes were measured in thirty individuals divided into three groups based on the electrode size. A novel Bayesian approach was used in addition to the classical hypothesis testing during data analyses. Results: There were no significant main or interaction effects, indicating that cortical excitability did not differ between different tDCS devices or electrode sizes. The lack of pre-post time effect in both experiments indicated that cortical excitability was minimally affected by anodal tDCS. Bayesian analyses indicated that the null model was more favored than the main or the interaction effects model. Conclusions: Motor cortical excitability was not altered by anodal tDCS and did not differ by devices or electrode sizes used in the study. Future studies should examine if behavioral outcomes are different based on tDCS device or electrode size.

2021 ◽  
Vol 2071 (1) ◽  
pp. 012052
N A Zulkiflli ◽  
M D Shahrulnizahani ◽  
X F Hor ◽  
F A Phang ◽  
M F Rahmat ◽  

Abstract Cell sensing and monitoring using capacitive sensors are widely used in cell monitoring because of the flexible and uncomplicated design and fabrication. Previous work from many different fields of applications has integrated capacitive sensing technique with tomography to produce cross-sectional images of the internal dielectric distribution. This paper carried an investigation on the capabilities of four 16-channel sensor electrodes with different electrode sizes to detect the change in the dielectric distribution of the cultured cells. All three 16-channel sensor electrodes are designed and simulate on COMSOL 6.3a Multiphysics. The pre-processing results obtained from three finite element models (FEM) of ECT sensor configurations in detecting the cell phantom shows that bigger electrodes size are more sensitive to permittivity distribution.

Heart Rhythm ◽  
2021 ◽  
Masateru Takigawa ◽  
Takeshi Kitamura ◽  
Shubhayu Basu ◽  
Meir Bartal ◽  
Claire A. Martin ◽  

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