An electric field modeling study with meta-analysis to understand the antidepressant effects of transcranial direct current stimulation (tDCS)

Objective: Transcranial direct current stimulation (tDCS) has mixed effects for major depressive disorder (MDD) symptoms, partially owing to large inter-experimental variability in tDCS protocols and their correlated induced electric fields (E-fields). We investigated whether the E-field strength of distinct tDCS parameters was associated with antidepressant effect. Methods: A meta-analysis was performed with placebo-controlled clinical trials of tDCS enrolling MDD patients. PubMed, EMBASE, and Web of Science were searched from inception to March 10, 2023. Effect sizes of tDCS protocols were correlated with E-field simulations (SimNIBS) of brain regions of interest (bilateral dorsolateral prefrontal cortex [DLPFC] and bilateral subgenual anterior cingulate cortex [sgACC]). Moderators of tDCS responses were also investigated. Results: A total of 20 studies were included (21 datasets, 1,008 patients), using 11 distinct tDCS protocols. Results revealed a moderate effect for MDD (g = 0.41, 95%CI 0.18-0.64), while cathode position and treatment strategy were found to be moderators of response. A negative association between effect size and tDCS-induced E-field magnitude was seen, with stronger E-fields in the right frontal and medial parts of the DLPFC (targeted by the cathode) leading to smaller effects. No association was found for the left DLPFC and the bilateral sgACC. An optimized tDCS protocol is proposed. Conclusions: Our results highlight the need for a standardized tDCS protocol in MDD clinical trials. Registration number: PROSPERO CRD42022296246.

Exploring occupational hazards and protective strategies in power generation enterprises / 中国职业医学

Currently, power generation in China is dominated by thermal power, wind power, nuclear power, and hydropower enterprises. The power source mainly comes from thermal power generation. The occupational hazards in thermal power station are noise, high temperature, power frequency electric fields, dust, and chemical toxins and so on, with noise and dust (silica and coal dust) being the primary factors. The occupational hazards in wind power station are noise, power frequency electric fields, high temperature, low temperature, and chemical toxins (sulfur hexafluoride, toluene, styrene, etc.), with noise and power frequency electric fields being the major concerns. The occupational radiation hazards in nuclear power station are gamma rays, beta rays, X-rays, neutrons, alpha rays, and radioactive aerosols. There is special attention in radiation protection but not enough protection in non-radioactive hazards such as noise, high temperature, and ammonia. The occupational hazards in hydropower station are noise, power frequency electric fields, vibration, radon and its de-composites, and chemical toxins, with noise and power frequency electric fields being the primary hazards. Different categories of power generation enterprises should identify key hazards and work site for occupational disease prevention and control based on the features of occupational hazards. Improving occupational health management and protection levels are essential measures.

The influence of tissue conductivity on the calculation of electric field in the transcranial magnetic stimulation head model / 生物医学工程学杂志

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.

Simulation Results and Analysis of Electric Field Distribution in Myocardial Tissue under Circular Electrode Electric Pulse Ablation / 中国医疗器械杂志

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.

Relaxation of thoracic aorta and pulmonary artery rings of marmosets (Callithrix spp.) by endothelium-derived 6-nitrodopamine

6-Nitrodopamine is a novel catecholamine released by vascular tissues, heart, and vas deferens. The aim of this study was to investigate whether 6-nitrodopamine is released from the thoracic aorta and pulmonary artery rings of marmosets (Callithrix spp.) and to evaluate the relaxing and anti-contractile actions of this catecholamine. Release of 6-nitrodopamine, dopamine, noradrenaline, and adrenaline was assessed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The relaxations induced by 6-nitrodopamine and by the selective dopamine D2 receptor antagonist L-741,626 were evaluated on U-46619 (3 nM)-pre-contracted vessels. The effects of 6-nitrodopamine and L-741,626 on the contractions induced by electric-field stimulation (EFS), dopamine, noradrenaline, and adrenaline were also investigated. Both aorta and pulmonary artery rings exhibited endothelium-dependent release of 6-nitrodopamine, which was significantly reduced by the NO synthesis inhibitor L-NAME. Addition of 6-nitrodopamine or L-741,626 caused concentration-dependent relaxations of both vascular tissues, which were almost abolished by endothelium removal, whereas L-NAME and the soluble guanylate cyclase inhibitor ODQ had no effect on 6-nitrodopamine-induced relaxations. Additionally, pre-incubation with 6-nitrodopamine antagonized the dopamine-induced contractions, without affecting the noradrenaline- and adrenaline-induced contractions. Pre-incubation with L-741,626 antagonized the contractions induced by all catecholamines. The EFS-induced contractions were significantly increased by L-NAME, but unaffected by ODQ. Immunohistochemical assays showed no immunostaining of the neural tissue markers S-100 and calretinin in either vascular tissue. The results indicated that 6-nitrodopamine is the major catecholamine released by marmoset vascular tissues, and it acts as a potent and selective antagonist of dopamine D2-like receptors. 6-nitrodopamine release may be the major mechanism by which NO causes vasodilatation.

Total electric field intensity in workplace of high-voltage direct current converter stations / 环境与职业医学

Background The converter stations of high-voltage direct current (HVDC) transmission lines generate special total electric fields. At present, few investigations have been conducted on total electric fields in the workplace of converter stations from an perspective of occupational health. Objective To understand the current situation of total electric field strength in the workplace of converter stations. Methods Using purposive sampling, a calibrated HDEM-1 direct current (DC) total electric field strength measurement system was used to measure the total electric fields of 12 converter stations serving 6 DC lines in Southeast and Southwest China according to the Measurement method for total electric field strength and ion current density of the converter stations and DC transmission lines (DL/T 1089—2008). The results were evaluated according to occupational exposure limits recommended by The limits of electromagnetic environment at ±800 kV UHV DC converter station (DL/T 275—2012), the American Conference of Governmental Industrial Hygienists (ACGIH), and the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Results A total of 615 check points were planned, the total electric field strength was 0.05-37.05 kV·m−1, and the median was 10.45 kV·m−1. The total electric field strength of 39 check points (6.3%) exceeded 25 kV·m−1 (the limits of ACGIH and ICNIRP), and the total electric field strength of 12 check points (2.0%) exceeded 30 kV·m−1 (the limit of DL/T 275—2012). There were statistically significant differences in the total electric field strength values and the proportions of exceeding 25 kV·m−1 between the neutral regions and the positive regions and between the neutral regions and the negative regions (P < 0.01). The proportion of total electric field strength exceeding 30 kV·m−1 in the negative regions was higher than that in the positive regions (P < 0.01). There were no significant differences in the total electric field strength of converter stations at different voltage levels and different altitudes (P > 0.05). There were no significant differences in the proportions of total electric field exceeding 25 kV·m−1 and exceeding 30 kV·m−1 in converter stations at different voltage levels and different altitudes (P > 0.05). Conclusion The total electric field in some workplace of converter stations exceeds selected limits. Converter station operators may be exposed to high-strength total electric field for a short time.

Combination effects of pulsed electric field and low temperature plasma on H22 mouse liver cancer cell / 中华肝胆外科杂志

Objective:To investigate the effect of pulsed electric field (PEF) combined with low temperature plasma (LTP) on mouse liver cancer cell.Methods:H22 mouse liver cancer cells were divided into liver cancer group, PEF treatment group, LTP treatment group, combined group A (first PEF treatment immediately after LTP treatment), combined group B (first LTP treatment immediately after PEF treatment), combined group C (same as combined group A, but 20 minutes interval) and combined group D (same as combined group B, but 20 minutes interval). Cell viability was detected by cell counting, apoptosis was detected by flow cytometry, intracellular reative oxygen species (ROS) was marked by fluorescence and counted. Twenty healthy female Kunming mouse aged 4-6 weeks without specific pathogens were subcutaneous injected with liver cancer cells, and then were randomly divided into model group, PBS control group, PEF experimental group, LTP experimental group and combined group (LTP+ PEF, no interval) ( n=4). Tumor relative volume and tumor inhibition rate were measured. Results:The survival rates were liver cancer cell group (98.3±0.9)%, PEF treatment group (66.8±4.4)%, LTP treatment group (62.1±3.9)%, combined group A (43.7±3.7)%, combined group B (31.0±1.4)%, combined group C (46.8±2.9)%, combined group D (39.0±2.3)%. Compared with liver cancer cell group, the cell survival rate of all treatment groups was decreased, and the cell survival rate of the four combined treatment group was lower than that of PEF treatment group and LTP treatment group, the differences were statistically significant (all P<0.05). The survival rate of combined B group was the lowest. The results of apoptosis detection were consistent with those of cell survival rate. Under fluorescence microscope, the ROS fluorescence of cells in the combined group B was significantly increased, and the ROS fluorescence of cells in the LTP treatment group was more than that in the PEF treatment group, and the percentage of ROS positive cells in the combined group B was higher than that in the LTP treatment group and the PEF treatment group, with statistical significance (all P<0.05). Tumor relative volume and tumor inhibition rate in the combined group were better than those in the PEF and LTP groups, and the differences were statistically significant (all P<0.05). Conclusion:LTP combined with PEF has a better killing effect on H22 cells than PEF or LTP treatment, which is expected to be a new tumor therapy.

Experimental study of electric field stimulation combined with polyethylene glycol in the treatment of spinal cord injury in rats / 生物医学工程学杂志

Electric field stimulation (EFS) can effectively inhibit local Ca 2+ influx and secondary injury after spinal cord injury (SCI). However, after the EFS, the Ca 2+ in the injured spinal cord restarts and subsequent biochemical reactions are stimulated, which affect the long-term effect of EFS. Polyethylene glycol (PEG) is a hydrophilic polymer material that can promote cell membrane fusion and repair damaged cell membranes. This article aims to study the combined effects of EFS and PEG on the treatment of SCI. Sprague-Dawley (SD) rats were subjected to SCI and then divided into control group (no treatment, n = 10), EFS group (EFS for 30 min, n = 10), PEG group (covered with 50% PEG gelatin sponge for 5 min, n = 10) and combination group (combined treatment of EFS and PEG, n = 10). The measurement of motor evoked potential (MEP), the motor behavior score and spinal cord section fast blue staining were performed at different times after SCI. Eight weeks after the operation, the results showed that the latency difference of MEP, the amplitude difference of MEP and the ratio of cavity area of spinal cords in the combination group were significantly lower than those of the control group, EFS group and PEG group. The motor function score and the ratio of residual nerve tissue area in the spinal cords of the combination group were significantly higher than those in the control group, EFS group and PEG group. The results suggest that the combined treatment can reduce the pathological damage and promote the recovery of motor function in rats after SCI, and the therapeutic effects are significantly better than those of EFS and PEG alone.

A new technology for the treatment of atrial fibrillation: pulsed electric field ablation / 国际生物医学工程杂志

Atrial fibrillation, also known as atrial fibrillation, is a common cardiac arrhythmia, and its incidence increases with age. Catheter ablation is considered to be an effective means to treat atrial fibrillation and maintain sinus rhythm. The common ablation technologies are radiofrequency ablation and cryoablation. However, the existing catheter ablation technology has a "zero-sum effect", and it is difficult to control the optimal dose clinically. In this study, a new method of pulsed electric field ablation for atrial fibrillation was proposed, which effectively solved the "zero-sum effect" problem of temperature ablation. The clinical application results show that the proposed technology effectively overcomes the shortcomings of existing temperature ablation, and can form durable pulmonary vein isolation.

Lever positioning manipulation combined with pulsed electric field on the analgesic effect of patients with lumbar disc herniation and its influence on IL-1β and TNF-α / 中国骨伤

OBJECTIVE@#To observe the analgesic effect of lever positioning manipulation combined with pulsed electric field on patients with lumbar disc herniation and the influence on serum IL-1β and TNF-α.@*METHODS@#From January 2018 to March 2019, 58 patients with lumbar disc herniation were included in the study, which were randomly divided into observation group and control group by digital table method. Observation group of 29 cases, including 16 males and 13 females, aged (38.03±11.29) years old, were treated with lever positioning manipulation combined with pulsed electric field. The 29 cases in control group, including 17 males and 12 females, aged (38.21±9.16) years old, were treated with pulsed electric field. Both groups of patients were treated 3 times a week, once every other day, 3 times as a course of treatment. After 2 courses of treatment, the two groups of patients were scored before and after treatment by the numeric rating scales (NRS);at the same time, the serum levels of IL-1β and TNF-α were measured before and after treatment.@*RESULTS@#The NRS scores of observation group and control group were 4.21±1.76, 4.66±1.61 before treatment, and 1.28±0.84, 2.10±1.35 after treatment, respectively. The NRS scores of the observation group after treatment was significantly lower than that of the control group (@*CONCLUSION@#The lever positioning manipulation combined with pulsed electric field has a good analgesic effect on patients with lumbar disc herniation, and it has a significant impact on the patient's serum IL-1β and TNF-α concentration, which can be used as a clinical guide. However, the synergistic effect of lever positioning technique combined with pulsed electric field and guidelines for clinical treatment need further research.

Progress in the Treatment of Tachyarrhythmia by Pulsed Electric Field Ablation Catheter Ablation / 中国医疗器械杂志

Pulsed electric field(PEF) provides high-energy instantaneous pulse and release energy to myocardial cell membrane, resulting in irreversible electroporation and causes myocardial cell contents leakage, destruction of intracellular homeostasis, cell death, and slight inflammatory response. PEF as non-thermal energy promotes the design and application of arrhythmia ablation catheter to enter a new stage. There are currently limited clinical studies that have proved the safety and effectieness of Farawave PEF catheter, PVAC GOLD PEF catheter, Lattice-tip Sphere-9 PEF and radiofrequency (RF) catheter used for atrial fibrillation ablation, but still need further discussion. The research of atrial fibrillation ablation with PEF is under study in China. In this paper, the design and application of PEF ablation for tachyarrhythmia are reviewed.

Current status of occupational exposure to power frequency electromagnetic field in converter stations / 中国职业医学

OBJECTIVE: To analyze the current status of occupational exposure to power frequency electromagnetic field in converter stations. METHODS: Eight converter stations with voltage levels of ±500 kV and ±800 kV within normal operation were selected as the research subjects using the typical sampling method. Power frequency electric field and power frequency magnetic field strengths were measured and calculated according to the GBZ/T 189.3-2018 Measurement of Physical Agents in Workplace--Part 3: Electric Field and Magnetic Field between 1 Hz and 100 kHz. The GBZ 2.2-2007 Occupational Exposure Limits for Hazardous Factors in the Workplace--Part 2: Physical Factors were used to evaluate whether the power frequency electric field strength exceeds the regulatory limit(the occupational exposure limit of power frequency electric field in 8 hours workplace is 5.000 kV/m). Meanwhile, the test results were evaluated according to the short-term occupational exposure limit of 50 Hz electric field and magnetic field recommended by the International Committee on Nonionizing Radiation Protection in 2010 that are 10.000 kV/m and 1 000.00 μT. RESULTS: The power frequency electric field and magnetic field strengths of 582 working environment detection points were measured. The median and 0-100 th percentile of power frequency electric field and power frequency magnetic field strength were 4.342(0.001-12.003) kV/m and 5.51(0.10-186.90) μT, respectively.The exceeding standard rate of power frequency electric field strength in converter station workplaces was 37.8%(220/582), which concentrated in 500 kV alternating current filter area and 500 kV alternating current field area. Among them, 5 detection points had power frequency electric field strength exceeding 10.000 kV/m. The magnetic flux density of all the detection points did not exceed 1 000.00 μT. The power frequency electric field strength in ultra-high voltage region was higher than that in high voltage region(P<0.01). There was no significant difference in power frequency magnetic field strength(P>0.05). There was no significant difference in power frequency electric field and magnetic field between rectifier stations and inverter stations(P>0.05). The 8 hours time weighted average(TWA) value of power frequency electric field strength of 8 converter station operators was 1.044-2.335 kV/m, which did not exceed the occupational exposure limit. CONCLUSION: The converter station operators might be exposed to excessive power frequency electric fields for a short time, but the 8 hours TWA value of the power frequency electric field meets the requirements of standards, and the power frequency magnetic field exposure strength also meets the requirements of the relevant standards.

Effect of high voltage electric field on cell growth, apoptosis of human pancreatic cancer cell line PANC-1 / 中华肝胆外科杂志

Objective To investigate the effects of high intensity electric field on cell growth,apoptosis and microstructure of human pancreatic cancer cell line PANC-1.Methods The PANC-1 cells in the logarithmic growth period were selected,and cells in the high voltage electrical treatment group were treated with high voltage electric field 250,500,750,1000 V/cm,respectively.The effects of different high voltage electric fields on cell growth and microstructure of PANC-1 cells were determined by cell viability,cell death staining,apoptosis detection,transmission electron microscopy and scanning electron microscopy.Results Compared with control group,the high voltage electric pulse significantly inhibited the growth of PANC-1 cells in the field dependent manner.Moreover,when the field was more than 500 V/cm,the cell viability was significantly decreased (P＜0.05).High voltage electric pulse could induce cell apoptosis.When the field was higher than 750 V/cm,serious necrosis was noticed.In the 1000 V/cm group,the integrity of cell membrane and the structure of organelles was seriously damaged.Conclusion High voltage electric pulse could significantly inhibit the growth of PANC-1 cells and would be a promising method in cancer treatment.

Applications of new methods in extraction of flavonoids from Chinese materia medica / 中草药

Flavonoids are widely found in medicinal plants, which have important medical properties. Flavonoids were proved to have many pharmacological activities, such as anti-oxidation, antitumor, antimutation, anti-inflammatory, antibacterial and anti-aging. The extraction of flavonoids is the crucial link in their clinical applications. In recent years, many emerging Chinese medicine extraction methods have also been widely used in the extraction of flavonoids. This paper reviews the current application of new methods for flavonoid extraction, in order to provide references for the extraction, development and utilization of flavonoids. These new extraction methods include supercritical fluid extraction (SFE), ultrasonic assisted extraction (UAE), microwave assisted extraction (MAE), pressurized liquid extraction (PLE), pulsed electric field (PEF) assisted extraction, enzyme assisted extraction (EAE), green solvent extraction, steam explosion assisted extraction, dynamic high pressure microfluidization (DHPM) assisted extraction, etc.

Evaluation uncertainty of power frequency electric field for a Power Project in inner Mongolia / 中华劳动卫生职业病杂志

Objective@#With the measurement and uncertainty analysis of the power frequency electric field of the main transformer in the power station, the source of uncertainty, its quantitative calculation, the synthetic assessment method and the reporting method of the measurement results are described to ensure the reliability of the power frequency electric field measurement data.@*Methods@#Referring to the "Measurement of power frequency electric field in the workplace" (GBZ/T189.3-2007) , "Labour environment monitoring technological specification of electric power industry Partt7: Monitoring of power frequency electromagnetic fields" (DL/T 799.7-2010) and "Evaluation and Expression of Uncertainty in Measurement" (JJF 1059.1-2012) , the uncertainty of power frequency electric field measurement data of the main transformer of a power plant was analyzed and the extended uncertainty was obtained.@*Results@#The main source of the uncertainty of power frequency electric field measurement was the measurement of repetitive operation, and the expanded uncertainty of power frequency electric field was 0.09 kV/m.@*Conclusion@#When reporting the results of power frequency electric field measurement, the measurement uncertainty should be used simultaneously to quantify the quality of the measurement results. This method has strong practicability and operability, which can meet the requirements of uncertainty evaluation of power frequency electric field measurement results.

Effect of the electric field on the migration and proliferation of human lens epithelial cells / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To observe the effect of applied direct electric field(EF)on the migration, cell growth, apoptosis and cell cycle of human lens epithelial cells(hLECs). <p>METHODS: HLE-B3 cells were exposed to EF at 100mV/mm, 200mV/mm and 400mV/mm, respectively. Cells without EF-exposure were treated as normal controls. Photos of HLE-B3 cells were captured before and after EF-exposure, and the cell numbers were calculated. Apoptosis and cell cycle were detected with flow cytometry after EF-exposure for 24h. <p>RESULTS: After exposure to EF at 400mV/mm for 3h, HLE-B3 cells showed directed migration to the cathode. The cell number of HLE-B3 cells decreased gradually with continuous EF-exposure, and decreased by 12.6% at 6h and by 18.6% at 12h, respectively(<i>P</i><0.05). After exposure to EF at 100mV/mm, 200mV/mm and 400mV/mm for 24h, the apoptosis rates of HLE-B3 cells increased dramatically compared to that of the normal control, which were(9.2±1.9)%,(23.9±2.6)% and(54±2.5)%, respectively(<i>P</i><0.05). Accordingly, the results of flow cytometry showed that cell numbers in G2/M phase were increased after EF-exposure, which were(13.8±2.2)% and(15.6±2.5)% at 200mV/mm and 400mV/mm, respectively(<i>P</i><0.05). <p>CONCLUSION: Applied direct EF induces directed migration of HLE-B3 cells and inhibits the cell growth with the prolongation of the EF-exposure time. EF also induces cell apoptosis and G2/M phase inhibition of the cell cycle in HLE-B3 cells.

Research of Unidirectional Ion Ejection in Printed-Circuit-Board Ion Trap / 分析化学

Printed-circuit-board ion trap (PCBIT) is a novel ion trap mass analyzer,which is capable of optimizing its internal electric field distributions by adjusting the radio frequency (RF) voltage-divided ratio to improve its analytical performance.This work introduced odd electric field components into the trapping volume to achieve unidirectional ion ejection by applying asymmetric RF voltages to x electrode pairs of PCBIT.In this case,the center of ion vibration was displaced away from the geometrical center of PCBIT and ions were ejected predominantly through one of x electrode pairs.The relationship between asymmetric voltage-divided ratio (AV) and internal electric field distributions was investigated by simulation software SIMION and AXSIM.At the same time,the ion trajectories and simulated mass spectrum peaks were calculated.The results showed that,for ions with m/z 609 Th,a mass resolution over 2500 and an ion unidirectional ejection efficiency of over 90％ were achieved in PCBIT with AV=20％ at an appropriate frequency of AC.Using this method,ion unidirectional ejection efficiency of PCBIT can be significantly improved while maintaining a high mass resolution,which makes the PCBIT more suitable for developing miniaturized mass spectrometer.

Realistic Electric Field Mapping of Anisotropic Muscle During Electrical Stimulation Using a Combination of Water Diffusion Tensor and Electrical Conductivity / 대한배뇨장애요실금학회지

PURPOSE: To realistically map the electric fields of biological tissues using a diffusion tensor magnetic resonance electrical impedance tomography (DT-MREIT) method to estimate tissue response during electrical stimulation. METHODS: Imaging experiments were performed using chunks of bovine muscle. Two silver wire electrodes were positioned inside the muscle tissue for electrical stimulation. Electric pulses were applied with a 100-V amplitude and 100-μs width using a voltage stimulator. During electrical stimulation, we collected DT-MREIT data from a 3T magnetic resonance imaging scanner. We adopted the projected current density method to calculate the electric field. Based on the relation between the water diffusion tensor and the conductivity tensor, we computed the position-dependent scale factor using the measured magnetic flux density data. Then, a final conductivity tensor map was reconstructed using the multiplication of the water diffusion tensor and the scale factor. RESULTS: The current density images from DT-MREIT data represent the internal current flows that exist not only in the electrodes but also in surrounding regions. The reconstructed electric filed map from our anisotropic conductivity tensor with the projected current density shows coverage that is more than 2 times as wide, and higher signals in both the electrodes and surrounding tissues, than the previous isotropic method owing to the consideration of tissue anisotropy. CONCLUSIONS: An electric field map obtained by an anisotropic reconstruction method showed different patterns from the results of the previous isotropic reconstruction method. Since accurate electric field mapping is important to correctly estimate the coverage of the electrical treatment, future studies should include more rigorous validations of the new method through in vivo and in situ experiments.

Research progress of electric field in the treatment of glioma / 国际肿瘤学杂志

Electric field treatment of tumor technology is of great significance in the treatment of glioma,including direct current electric field and alternating electric field.Direct current electric field affects the migration of glioma cells,and can be used as a new clue for the treatment of glioma.While alternating electric field can inhibit the proliferation and invasion of glioma cells,and induce apoptosis,and can obviously prolong the survival period of patients with glioma and improve their quality of life.

Inter-laboratory comparisons of measuring instruments for power frequency electromagnetic fields in the workplace / 中国职业医学

OBJECTIVE: To evaluate the major influence factors affecting the quality and accuracy of measuring instruments for power frequency electromagnetic fields in occupational hygiene technical service organizations by developing interlaboratory comparison in workplaces. METHODS: Six measuring instruments for power electromagnetic fields from 6occupational hygiene technical service organizations in Guangdong Province were selected by typical sampling method. A high-voltage substation was selected as a standard source. We set measurement sites underneath it as inter-laboratory comparison spots for power frequency electromagnetic fields. The stability of the standard source was evaluated by pairedsamples t-test and measure results were analyzed by z-score evaluation method based on quartile robust statistical technology. RESULTS: During and after the inter-laboratory comparison,the intensity of electric field and magnetic field of the standard source showed no significant difference [( 555. 03 ± 2. 94) vs( 555. 68 ± 3. 20) V / m,( 2. 30 ± 0. 06) vs( 2. 29 ± 0. 07) μT,P > 0. 05],which met the demand of stability of inter-laboratory comparison. The data of electric field measured by 2 measuring instruments without remote-reading system were found to be high because of proximity effect from its handheld status. The z-score of inter-laboratory( zB) of other 4 measuring instruments with remote-reading system ranged from- 0. 52 to 1. 10,while the z-score of within-laboratory( zW) ranged from- 1. 28 to 0. 37,and both results of| zB| and | zW| were satisfactory( < 2. 00). The zBof power frequency magnetic field measured by the 6 measuring instruments ranged from- 0. 67 to 1. 26,while zWranged from- 0. 59 to 0. 90,and both | zB| and | zW| were also satisfactory( < 2. 00). CONCLUSION: It is feasible that the inter-laboratory comparison of measuring instruments of power frequency electromagnetic fields could be implemented by a high-voltage substation as a standard source. The measuring instruments without remote-reading system could be used to measure the intensity of magnetic field but not the electric field. The measuring instruments with remote-reading system could be used to measure the intensity of either the electric field or the magnetic field,and the measurement results are satisfactory.