In transcranial magnetic stimulation (TMS), the conductivity of brain tissue is obtained by using diffusion tensor imaging (DTI) data processing. However, the specific impact of different processing methods on the induced electric field in the tissue has not been thoroughly studied. In this paper, we first used magnetic resonance image (MRI) data to create a three-dimensional head model, and then estimated the conductivity of gray matter (GM) and white matter (WM) using four conductivity models, namely scalar (SC), direct mapping (DM), volume normalization (VN) and average conductivity (MC), respectively. Isotropic empirical conductivity values were used for the conductivity of other tissues such as the scalp, skull, and cerebrospinal fluid (CSF), and then the TMS simulations were performed when the coil was parallel and perpendicular to the gyrus of the target. When the coil was perpendicular to the gyrus where the target was located, it was easy to get the maximum electric field in the head model. The maximum electric field in the DM model was 45.66% higher than that in the SC model. The results showed that the conductivity component along the electric field direction of which conductivity model was smaller in TMS, the induced electric field in the corresponding domain corresponding to the conductivity model was larger. This study has guiding significance for TMS precise stimulation.
Transcranial Magnetic Stimulation ; Diffusion Tensor Imaging ; Electric Conductivity ; Electricity ; Scalp

As a new energy source for atrial fibrillation ablation, electric pulse ablation has higher tissue selectivity and biosafety, so it has a great application prospect. At present, there is very limited research on multi-electrode simulated ablation of histological electrical pulse. In this study, a circular multi-electrode ablation model of pulmonary vein will be built on COMSOL5.5 platform for simulation research. The results show that when the voltage amplitude reaches about 900 V, it can make some positions achieve transmural ablation, and the depth of continuous ablation area formed can reach 3 mm when the voltage amplitude reaches 1 200 V. When the distance between catheter electrode and myocardial tissue is increased to 2 mm, a voltage of at least 2 000 V is required to make the depth of continuous ablation area reach 3 mm. Through the simulation of electric pulse ablation with ring electrode, the research results of this project can provide reference for the voltage selection in the clinical application of electric pulse ablation.
Humans ; Heart Rate ; Atrial Fibrillation/surgery* ; Electrodes ; Catheter Ablation ; Electricity

Objective: To investigate the characteristics of the time-point distribution of the occurrence of laryngopharyngeal reflux (LPR) by 24-hour multichannel intraluminal impedance-pH monitoring (24 h MII-pH) and to provide guidance for the development of individualized anti-reflux strategies for LPR patients. Methods: We conducted a retrospective analysis of 24 h MII-pH data from 408 patients [339 males and 69 females, aged 23-84 (55.08±11.08) years] attending the Department of Otorhinolaryngology Head and Neck Surgery at the Sixth Medical Center of the PLA General Hospital from January 2013 to March 2020. The number of gas acid/weak-acid reflux, mixed gas-liquid acid/weak-acid reflux, liquid acid/weak-acid reflux and alkaline reflux events at different time points were recorded and statistically analyzed through SPSS 26.0 software. Results: A total of 408 patients were included. Based on the 24 h MII-pH, the total positive rate of LPR was 77.45% (316/408). The type of positive gaseous weak-acid reflux was significantly higher than the remaining types of LPR (χ²=297.12,P<0.001). Except the gaseous weak-acid reflux, the occurrence of the remaining types of LPR showed a tendency to increase after meals, especially after dinner. Liquid acid reflux events occurred mainly between after dinner and the following morning, and 47.11% (57/121) of them occurred within 3 h after dinner. There was a significant positive association between Reflux Symptom Index scores and gaseous weak-acid reflux(r=0.127,P<0.01), liquid acid reflux(r=0.205,P<0.01) and liquid weak-acid reflux(r=0.103,P<0.05)events. Conclusions: With the exception of gaseous weak-acid reflux events, the occurrence of the remaining types of LPR events has a tendency to increase after meals, especially after dinner. Gaseous weak-acid reflux events accounts for the largest proportion of all types of LPR events, but the pathogenic mechanisms of gaseous weak-acid reflux are needed to further investigate.
Male ; Female ; Humans ; Laryngopharyngeal Reflux/diagnosis* ; Retrospective Studies ; Esophageal pH Monitoring ; Otolaryngology ; Software ; Electric Impedance

Synthetic electroactive microbial consortia, which include exoelectrogenic and electrotrophic communities, catalyze the exchange of chemical and electrical energy in cascade metabolic reactions among different microbial strains. In comparison to a single strain, a community-based organisation that assigns tasks to multiple strains enables a broader feedstock spectrum, faster bi-directional electron transfer, and greater robustness. Therefore, the electroactive microbial consortia held great promise for a variety of applications such as bioelectricity and biohydrogen production, wastewater treatment, bioremediation, carbon and nitrogen fixation, and synthesis of biofuels, inorganic nanomaterials, and polymers. This review firstly summarized the mechanisms of biotic-abiotic interfacial electron transfer as well as biotic-biotic interspecific electron transfer in synthetic electroactive microbial consortia. This was followed by introducing the network of substance and energy metabolism in a synthetic electroactive microbial consortia designed by using the "division-of-labor" principle. Then, the strategies for engineering synthetic electroactive microbial consortiums were explored, which included intercellular communications optimization and ecological niche optimization. We further discussed the specific applications of synthetic electroactive microbial consortia. For instance, the synthetic exoelectrogenic communities were applied to biomass generation power technology, biophotovoltaics for the generation of renewable energy and the fixation of CO₂. Moreover, the synthetic electrotrophic communities were applied to light-driven N₂ fixation. Finally, this review prospected future research of the synthetic electroactive microbial consortia.
Microbial Consortia ; Synthetic Biology ; Electron Transport ; Electricity ; Biodegradation, Environmental

Existing neuroregulatory techniques can achieve precise stimulation of the whole brain or cortex, but high-focus deep brain stimulation has been a technical bottleneck in this field. In this paper, based on the theory of negative permeability emerged in recent years, a simulation model of magnetic replicator is established to study the distribution of the induced electric field in the deep brain and explore the possibility of deep focusing, which is compared with the traditional magnetic stimulation method. Simulation results show that a single magnetic replicator realized remote magnetic source. Under the condition of the same position and compared with the traditional method of stimulating, the former generated smaller induced electric field which sharply reduced with distance. By superposition of the magnetic field replicator, the induced electric field intensity could be increased and the focus could be improved, reducing the number of peripheral wires while guaranteeing good focus. The magnetic replicator model established in this paper provides a new idea for precise deep brain stimulation, which can be combined with neuroregulatory techniques in the future to lay a foundation for clinical application.
Brain ; Cerebral Cortex ; Computer Simulation ; Electricity ; Magnetic Fields

Aiming at the human-computer interaction problem during the movement of the rehabilitation exoskeleton robot, this paper proposes an adaptive human-computer interaction control method based on real-time monitoring of human muscle state. Considering the efficiency of patient health monitoring and rehabilitation training, a new fatigue assessment algorithm was proposed. The method fully combined the human neuromuscular model, and used the relationship between the model parameter changes and the muscle state to achieve the classification of muscle fatigue state on the premise of ensuring the accuracy of the fatigue trend. In order to ensure the safety of human-computer interaction, a variable impedance control algorithm with this algorithm as the supervision link was proposed. On the basis of not adding redundant sensors, the evaluation algorithm was used as the perceptual decision-making link of the control system to monitor the muscle state in real time and carry out the robot control of fault-tolerant mechanism decision-making, so as to achieve the purpose of improving wearing comfort and improving the efficiency of rehabilitation training. Experiments show that the proposed human-computer interaction control method is effective and universal, and has broad application prospects.
Humans ; Exoskeleton Device ; Muscle Fatigue ; Muscles ; Algorithms ; Electric Impedance

Magneto-acoustic-electric tomography (MAET) boasts high resolution in ultrasound imaging and high contrast in electrical impedance imaging, making it of significant research value in the fields of early tumor diagnosis and bioelectrical monitoring. In this study, a method was proposed that combined high conductivity liquid metal and maximum length sequence (M sequence) coded excitation to improve the signal-to-noise ratio. It was shown that, under rotational scanning, the liquid metal significantly improved the signal-to-noise ratio of the inter-tissue magneto-acoustic-electric signal and enhanced the quality of the reconstructed image. The signal-to-noise ratio of the signal was increased by 5.6, 11.1, 21.7, and 45.7 times under the excitation of 7-, 15-, 31-, and 63-bit M sequence code, respectively. The total usage time of 31-bit M sequence coded excitation imaging was shortened by 75.6% compared with single-pulse excitation when the same signal-to-noise ratio was improved. In conclusion, the imaging method combining liquid metal and M-sequence coding excitation has positive significance for improving MAET image quality.
Contrast Media ; Electricity ; Electric Conductivity ; Acoustics ; Tomography

Bl factor is a key system parameter of the resonant blood viscoelastic sensor. In this paper, a dynamic measurement system for the spatial distribution of Bl factor based on velocity amplitude and motional impedance was designed. The system extracted the velocity amplitude and motional impedance of the coil under the dynamic condition of driving the sensor to generate simple harmonic oscillations using laser displacement and impedance analysis combined with in-phase/quadrature demodulation algorithm, and controlled the equilibrium position of the coil by adjusting the direct current component of the excitation current to realize the position scanning. In the position interval of [-240, 240] μm, the maximum coefficient of variation of the measurement results was 0.077 3%, and the maximum relative error to the simulation results was 2.937 9%, with a linear fitting correlation coefficient R ² = 0.996 8. The system can be used to accurately measure the spatial distribution of Bl factor of the resonant blood viscoelastic sensor, which provides a technical support for the verification of the design of the sensor magnetic circuit.
Computer Simulation ; Electric Impedance ; Motion ; Algorithms ; Lasers

Electrical impedance tomography (EIT) is an emerging technology for real-time monitoring based on the impedance differences of different tissues and organs in the human body. It has been initially applied in clinical research as well as disease diagnosis and treatment. Lung perfusion refers to the blood flow perfusion function of lung tissue, and the occurrence and development of many diseases are closely related to lung perfusion. Therefore, real-time monitoring of lung perfusion is particularly important. The application and development of EIT further promote the monitoring of lung perfusion, and related research has made great progress. This article reviews the principles of EIT imaging, lung perfusion imaging methods, and their clinical applications in recent years, with the aim of providing assistance to clinical and scientific researchers.
Humans ; Electric Impedance ; Lung/physiology* ; Tomography, X-Ray Computed ; Perfusion ; Tomography/methods*

Power supply plays a key role in ensuring animal robots to obtain effective stimulation. To extending the stimulating time, there is a need to apply photovoltaic cells and monitor their parameter variations, which can help operators to obtain the optimal stimulation strategy. In this paper, an online monitoring system of photovoltaic cells for animal robot stimulators was presented. It was composed of battery information sampling circuit, multi-channel neural signal generator, power module and human-computer interaction interface. When the signal generator was working, remote navigation control of animal robot could be achieved, and the battery voltage, current, temperature and electricity information was collected through the battery information sampling circuit and displayed on the human-computer interaction system in real time. If there was any abnormal status, alarm would be activated. The battery parameters were obtained by charging and discharging test. The battery life under different light intensity and the stimulation effect of neural signal generator were tested. Results showed that the sampling errors of battery voltage, current and electric quantity were less than 15 mV, 5 mA and 6 mAh, respectively. Compared with the system without photovoltaic cells, the battery life was extended by 148% at the light intensity of 78 320 lx, solving the battery life problem to some extent. When animal robot was stimulated with this system, left and right turns could be controlled to complete with the success rate more than 80%. It will help researchers to optimize animal robot control strategies through the parameters obtained in this system.
Animals ; Humans ; Robotics ; Electric Power Supplies ; Electricity ; User-Computer Interface