Taquicardia ventricular polimórfica tipo Torsadess de Pointes secundaria a estimulación por marcapasos

La taquicardia ventricular polimórfica se origina en los ventrículos, cuyos complejos QRS son de morfología, amplitud y dirección variable, con frecuencias que oscilan entre 200 y 250 lpm, pudiendo ser autolimitadas o degenerar en una fibrilación ventricular. La TdP es un tipo de taquicardia ventricular polimórfica caracterizada por complejos con un eje eléctrico que gira alrededor de la línea isoeléctrica y que está asociada a QT largo. Se presenta el caso de una paciente portadora de marcapaso que presenta episodios de taquicardia ventricular polimórfica, con una morfología típica de TdP, sin documentación de QT prolongado previo ni actual, generada por la estimulación ventricular sobre onda T, de forma accidental por desplazamiento del electrodo auricular a Ventrículo Derecho (VD).

Polymorphic ventricular tachycardia is a tachycardia originating in the ventricles, where the QRS complexes have variable morphology, amplitude, and direction, with frequencies ranging between 200 and 250 bpm; it may be self-limited or degenerate into ventricular fibrillation. Torsades de Pointes (TdP) is a type of polymorphic ventricular tachycardia characterized by complexes with an electrical axis that rotates around the isoelectric line and that is associated with long QT interval. We present the case of a patient with a pacemaker who presents episodes of polymorphic ventricular tachycardia, with a typical morphology of TdP, without documentation of previous or current prolonged QT, generated by ventricular stimulation on the T wave, accidentally due to displacement of the atrial electrode to the Right Ventricle (RV).

STUDY ON THE EFFECT OF BRASS AND COPPER ELECTRODES DURING ELECTRIC DISCHARGE MACHINING OF INCONEL 718 USING NANO PARTICLES MIXED DIELECTRIC FLUID.

Electrical Discharge Machine (EDM) parameters have a significant influence on machining characteristic like material removal rate (MMR) and tool wear rate (TWR). Inconel 718, which is widely used in the Medical, Marine, Architectural and food processing industries, is used as a work material. The tool electrode materials used are brass and copper. Experiments are conducted using face centered central composite design to determine the effects of process parameters like current rate, pulse on time, pulse off time and concentration of titanium carbide nano particle in dielectric fiuid. Based upon the experimental outcomes, the effect of brass and copper electrodes during electric discharge machining of Inconel 718 using nano particles mixed dielectric fiuid was investigated.

The past,present,and future of in vivo-implant-able recording microelectrodes:the neural interfaces / 中国药理学与毒理学杂志

Neural recording electrodes enable the acquisition and collection of electrical signals from neu-rons,and these recorded neural electrical signals are an important means of understanding neuronal activity.As a major component of the brain-machine interface,neu-ral recording electrodes serve as a bridge between the nervous system and external devices.The extracted information can be used to understand the state of the brain and acts as a feedback signal to regulate external devices,thus providing important information for the clini-cal treatment of neurological diseases.Moreover,the electrodes can be used as a vehicle for drug injection to directly treat diseases.Since the time that Strumwas-ser used microwires to achieve long-term recordings of neural activity in hibernating squirrels,implantable elec-trode technology has gradually improved over three gen-erations of development,and progress has been made in improving the biocompatibility,mechanical performance(size,shape,density,etc.),and signal-to-noise ratio.Implantable neural recording electrodes can acquire sig-nals from cortical and deep neural clusters,with the advantages of high signal-to-noise ratio,information con-tent,and spatial/temporal resolution.However,there is still a need to improve the structure and performance of these electrodes;for example,their high invasiveness and lack of biocompatibility pose technical difficulties in the process of translation to the clinic.This paper reviews the basic requirements for electrodes,main recording methods and signal types,common types of implant-able neural recording electrodes,and their challenges and future development directions.With the continuous development of electrode materials,equipment,systems,and neurotechnology,it should be possible to apply neu-ral recording electrodes in clinical practice,to promote safe and efficient treatment of human diseases.

Design, Simulation and Experimental Study of a Novel Radiofrequency Tissue Welding Electrode / 医用生物力学

Objective Aiming at improving biomechanical strength of the anastomotic stoma as well as reducing tissue thermal damage, a novel radiofrequency (RF) tissue welding electrode was developed. Methods A novel electrode with a hollow structure on the surface ( the plum electrode) was designed and the ring electrode was used as control group to conduct the welding of intestinal tissues based on RF energy. Biomechanical properties of anastomotic stoma were studied by shear test and burst pressure test. The tissue thermal damage during welding was investigated by finite element electro-thermal-mechanical multi-field coupling simulation analysis and thermocouple probe, and the tissue microstructures were also studied. Results Under 120 W RF energy, 8 s welding duration and 20 kPa compression pressure, the anastomotic stoma had the optimal biomechanical properties. Compared with the ring electrode group, biomechanical strength of the anastomotic stoma in plum electrode group was higher, with the shear strength and burst pressure increasing from (9. 7±1. 47) N, (84. 0±5. 99) mmHg to (11. 1±1. 71) N, (89. 4±6. 60) mmHg, respectively. There was a significant reduction in tissue thermal damage, and intact and fully fused stomas could be formed in anastomotic area. Conclusions The proposed novel electrode could improve biomechanical strength of the anastomosis as well as reduce tissue hermal damage, thus achieve better fusion. The research result provide references for realizing the seamless connection of human lumen tissues

Application of minimally invasive percutaneous nephroscopic plasma electrode decortication in the treatment of renal cysts / 现代泌尿外科杂志

Laparoscopic decortication is the standardized surgical treatment for simple renal cysts. With the continuous maturation of minimally invasive techniques, percutaneous nephroscopic decortication and decompression is gradually implemented, which has advantages of minimal invasiveness, fast recovery and good prognosis. Ureteroscopic plasma electrode is a modified procedure, which can achieve more exact intraoperative hemostasis and efficient cutting efficiency than traditional surgery. This article reviews the current treatments of simple renal cysts, and introduces our experience of using minimally invasive percutaneous nephroscopic plasma electrode decortication, its surgical procedures and technical points.

Cochlear electrode array misplacement into the superior semicircular canal: a case report and literature review / 临床耳鼻咽喉头颈外科杂志

Electrode array misplacement is a rare complication of cochlear implant. This article reports an 11-year-old boy who was mistakenly implanted the cochlear electrode array into the superior semicircular canal during the initial cochlear implant. After the diagnosis was confirmed, he underwent a second cochlear implant and the electrode array were successfully implanted into the cochlea. This article conducted a systematic review of the literature on electrode array misplacement, and the causes of electrode array misplacement were analyzed from different implantation position.

Fetal ECG Detection System Based on WiFi Data Transmission / 中国医疗器械杂志

Fetal ECG monitoring is a routine clinical detection method that can reflect the changes of fetal heart in utero in real time. At present, most of the clinical fetal heart rate detection adopts the ultrasonic Doppler method, which is technically difficult and highly specialized in operation and expensive. This study introduces a fetal ECG detection system based on the maternal abdominal electrode method. The weak fetal ECG changes are sensed through the maternal abdominal electrode, and the mixed ECG signal is obtained through the corresponding amplification and filtering circuit. Finally, the obtained signal is passed through WiFi, transmitted to the host computer. The host computer uses the adaptive filtering algorithm to estimate the fetal ECG signal. The system has strong feasibility, low operation expertise, low cost, and is more convenient.

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.

Implante de un electrodo de estimulación ventricular izquierdo mediante doble canulación del seno coronario, técnica de snare y acceso retrógrado de la vena posterolateral / Implant of a left ventricular pacing electrode by double cannulation of the coronary sinus, snare technique and retrograde access of the posterolateral vein

Resumen El implante percutáneo de un electrodo de estimulación ventricular izquierdo a través del seno coronario para resincronización cardiaca siempre ha implicado un reto y más aún en pacientes con anatomía venosa coronaria compleja. Este caso demuestra cómo una técnica de doble canulación del seno coronario con uso de catéter multi-snare permite la colocación exitosa de un electrodo de estimulación ventricular izquierdo mediante acceso retrógrado a una vena posterolateral estenótica.

Abstract The percutaneous implantation of a left ventricular pacing electrode through the coronary sinus for cardiac resynchronization has always been a challenge, especially in patients with a complex coronary venous anatomy. This case shows how double cannulation of the coronary sinus using a multisnare catheter allows a left ventricular pacing electrode to be placed through retrograde access to a stenotic posterolateral vein, with a good clinical outcome.

Evaluation of sacral neuromodulation system with new six-contact points electrode for the treatment of bladder dysfunction / 中华泌尿外科杂志

Objective:To investigate the effects of sacral neuromodulation (SNM)using the new six-contact electrode vs. the four-contact electrode in patients with refractory overactive bladder.Methods:The clinical data of 29 patients underwent SNM testing therapy from January 2018 to January 2020 in China Rehabilitation Research Center were reviewed. In six-contact points electrode group 16 patients accepted SNM with new six-contact points electrode, while 13 patients in four-contact points electrode group accepted SNM with four-contact points electrode. There were no significant differences between the two group in age [(51.63±4.67) vs. (51.85±7.18) years], gender (male/female, 4/12 and 5/8), urination frequency [(22.10±9.05) vs. (21.79±8.05) times/24h], mean voided volume [(135.68±56.98) vs. (131.00±53.05) ml], and urgency score [(2.78±0.97) vs. (3.02±0.91)] (all P>0.05). The number of sensitive contact points, the ratio of reaction contact points, operation time of stage I and the success rate of two groups were calculated. Results:The mean number of sensitive points of six-contact points electrode group (3.31± 0.95) was significantly higher than that of the four-contact points electrode group (1.85± 0.38), ( P<0.05). There was no significant difference in the ratio of reaction contact points [ (96.87±6.71)% vs. (96.15± 9.39)%] and operation time of stage I [(71.25± 18.21)min vs.(68.85± 10.83)min]between six-contact points electrode group and four-contact points electrode group ( P<0.05). The contact E4 and E5 of six-contact electrodes had similar reaction voltage ( P>0.05). The implant rate of six-contact points electrode group was (14/16, 87.5%), which was higher than that of four-contact points electrode group (10/13, 76.9%), but there was no statistical difference ( P>0.05). Conclusions:This study showed that six-contact electrodes has more sensitive points compared with four-contact electrodes. Application of six contact electrodes, patients might get a higher implant rate.

Modified transcricothyroid electrode recording method for monitoring recurrent laryngeal nerve function during thyroidectomy / 中华内分泌外科杂志

Objective:To study the safety, validity and practicability of the modified trans-cricothyroid needle electrode method for neurmonitoring during thyroidectomy.Methods:115 patients from the Department of Thyroid Surgery in Peking University Shenzhen Hospital scheduled for thyroid surgery were recruited into the group. Two paired needle electrodes were obliquely inserted into the cricothyroid membrane from the angle between the rectus cricothyroid muscle and the inferior margin of thyroid cartilage. The function of recurrent laryngeal nerve (RLN) was localized, exposed and evaluated by standard four-step method (V1-R1-R2-V2) . The vocal cord movement was evaluated by electronic laryngoscope before and after operation, and t-test was used to compare the difference of EMG signal amplitude before and after operation.Results:A total of 130 RLN from 115 patients were recorded effective electromyographic (EMG) signals, including 12 cases of giant goiter with tracheal compression stenosis; 13 cases had repeated adjustments of the position of tracheal intubation electrode during operation, but EMG signals were not satisfactory; 15 cases were with of accidental findings during operation and requiring neurmonitoring, but tracheal intubation electrodes were not used in advance. 75 cases were volunteers. The signals of 3 RLN were lost during operation. On the second day after operation, electronic laryngoscope showed that 2 cases had normal vocal cord movement and 1 case had vocal cord paralysis and no recovery for 6 months follow-up. The EMG signals of other 127 nerves were V1/R1=1857±1718μV/2347±2323μV, V2/R2=1924±1705μV/2450±2345μV. There was no significant difference in EMG signals between pre-operation and post-operation ( t=0.31/0.35, P=0.755/0.725) . The electronic laryngoscope showed normal vocal cord movement before and after operation. During the operation, 2 patients had a little bleeding at the needle electrode insertion point, which stopped after 5 minutes of compression. No electro-acupuncture breakage, infection or local hematoma occurred. Conclusions:The modified trans-cricothyroid needle electrode method had been proved to be safe and feasible for evaluating the function of recurrent laryngeal nerve in thyroid surgery. Besides of unaffected by tracheal conditions, it has good stability, simple implantation and low cost. In thyroid surgery, it can be used as a useful supplement to endotracheal intubation electrode.

Development of Non-invasive Endoscope System with Magnetic Anchored Ablation Electrode for Early Cancer of Digestive Tract / 中国医疗器械杂志

This study introduces a non-invasive gastrointestinal early cancer magnetic anchor ablation electrode endoscopy system, including a magnetic anchor module and ablation electrode module. The magnetic anchoring module is composed of an external guide magnet and an internal magnet, made of permanent magnet material NdFeB; the ablation electrode module is based on the modification of the front end lens hood of the existing endoscope (CMD-90D LED electronic upper gastrointestinal endoscope). The new endoscope system not only includes all the functions of the original endoscope, but also introduces magnetic anchoring to enable the ablation electrode to be accurately positioned and controllable in the process of treating tumors, avoiding the phenomenon of gastric perforation; the introduction of steep pulse electric field ablation electrodes realizes the purpose of non-invasive treatment. Its clinical application will become a new method to treat early cancer of the digestive tract.

A comparative study of microwire electrode array with built-in and external reference electrodes / 中国应用生理学杂志

Objective: To compare the difference between the built-in and external reference electrode of microwire electrode array in the process of recording rat brain neuron firings, optimizing the production and embedding of the microwire electrode array, and providing a more affordable and excellent media tool for multi-channel electrophysiological real-time recording system. Methods: A 16 channel microwire electrode array was made by using nickel chromium alloy wires, circuit board, electrode pin and ground wires (silver wires). The reference electrode of the microwire electrode array was built-in (the reference electrode and electrode array were arranged in parallel) or external (the reference electrode and ground wire were welded at both ends of one side of the electrode), and the difference between the two electrodes was observed and compared in recording neuronal discharges in ACC brain area of rats. Experimental rats were divided into built-in group and external group, n=8-9. The test indicators included signal-to-noise ratio (n=8), discharge amplitude (n=380) and discharge frequency (n=54). Results: The microwire electrode array with both built-in and external reference electrodes successfully recorded the electrical signals of neurons in the ACC brain region of rats. Compared with the external group, the electrical signals of neurons in built-in group had the advantages of a higher signal-to-noise ratio (P＜0.05), a smaller amplitude of background signals and less noise interference, and a larger discharge amplitude(P＜0.05); there was no significant difference in spike discharge frequency recorded by these two types of electrodes (P＞0.05). Conclusion: When recording the electrical activity of neurons in the ACC brain region of rats, the microwire electrode array with built-in reference electrode recorded electrical signals with higher signal-to-noise ratio and larger discharge amplitude, providing a more reliable tool for multi-channel electrophysiology technology.

Síndrome de reel como causa del mal funcionamiento del marcapasos: A propósito de un caso / Reel syndrome as cause of pacemaker malfunction: Apropos of a case

Implantation of cardiac electronic devices is an increasingly common technique and the possibility of device dysfunction caused by electrode displacement should be taken into account. We describe the case of an 88-year-old patient with syncopes several months after pacemaker implantation in which a pacemaker dysfunction was found. Chest X-ray confirmed lead displacement reeled around the generator. Reel syndrome is an entity that should be ruled out as a possible cause of pacemaker malfunction mainly in patients with risk factors for developing this syndrome.

La implantación de dispositivos cardíacos electrónicos es una técnica cada vez más habitual y debe tenerse en cuenta la posibilidad de disfunción del dispositivo debido al desplazamiento de los electrodos. Describimos el caso de una paciente de 88 años que comenzó con clínica de cuadros sincopales varios meses después de la implantación de un marcapasos, y en la que se demostró una disfunción del dispositivo. Mediante radiografía de tórax se confirmó el desplazamiento de los electrodos debido a un enrollamiento alrededor del generador. El síndrome de reel es una entidad que debe ser descartada como una de las posibles causas de mal funcionamiento de un marcapasos, principalmente en pacientes con factores de riesgo para presentar dicho síndrome.

Voltammetric Determination of Ascorbic Acid in Pharmaceutical Formulations Using Modified Iodine-Coated Platinum Electrode / Determinación voltamétrica del ácido ascórbico en formulaciones farmacéuticas utilizando un electrodo de platino modificado recubierto de yodo

Background: Despite the high reactivity of the platinum electrode, the iodine-coated platinum electrode shows obvious inertness toward adsorption and surface processes. For that, iodine-coated platinum electrodes accommodate themselves to interesting voltammetric applications. Objectives: This study reports using the modified iodine-coated polycrystalline platinum electrode as a voltammetric sensor for ascorbic acid determination in pharmaceutical formulations. Methods: The developed voltammetric method based on recording cyclic voltammograms of ascorbic acid at iodine-coated electrode The optimized experimental parameters for the determination of ascorbic acid were using 0.1 M KCl as a supporting electrolyte with a scan rate of 50mV/s. Results: The anodic peak related to ascorbic acid oxidation was centered at nearly 0.28V. An excellent and extended linear dependence of the oxidative peak current on the concentration of ascorbic acid was observed in the range 2.84x10-3 - 5.68 mM. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.0 µM and 3.01 µM, respectively, attesting to the method's sensitivity. The investigation for the effect of potential interference from multivitamin tablet ingredients (vitamins B1, B6, B12, folic acid, citric acid, sucrose, glucose, and zinc) indicated specific selectivity toward ascorbic acid and the absence of any electrochemical response toward these components. Recovery results in the range 98.93±2.78 - 99.98±5.20 for spiked standard ascorbic acid in pharmaceutical formulations further confirmed the potential applicability of the developed method for the determination of ascorbic acid in real samples. Conclusions: The developed method was successfully applied to the analysis of ascorbic acid (vitamin C), and the obtained results were in good agreement with the labeled values; besides, the statistical tests indicated no significant difference at p=0.05 with a 95% confidence level

Antecedentes: A pesar de su alta reactividad, el electrodo de platino recubierto de yodo muestra una inercia evidente hacia la adsorción y los procesos superficiales. Por ello, los electrodos de platino recubiertos de yodo se adaptan a interesantes aplicaciones voltamétricas. Objetivos: Este estudio informa sobre el uso del electrodo de platino policristalino recubierto de yodo modificado como sensor voltamétrico para la determinación del ácido ascórbico en formulaciones farmacéuticas. Métodos: El método voltamétrico desarrollado se basa en el registro de voltamperogramas cíclicos del ácido ascórbico en el electrodo recubierto de yodo Los parámetros experimentales optimizados para la determinación del ácido ascórbico fueron utilizando KCl 0,1 M como electrolito de soporte con una velocidad de barrido de 50mV/s. Resultados: El pico anódico relacionado con la oxidación del ácido ascórbico se centró en casi 0,28V. Se observó una excelente y extendida dependencia lineal de la corriente del pico oxidativo con respecto a la concentración de ácido ascórbico en el rango 2,84x10-3 - 5,68 mM. El límite de detección (LOD) y el límite de cuantificación (LOQ) fueron 1,0 µM y 3,01 µM, respectivamente, lo que demuestra la sensibilidad del método. La investigación del efecto de la interferencia potencial de los ingredientes de las tabletas multivitamínicas (vitaminas B1, B6, B12, ácido fólico, ácido cítrico, sacarosa, glucosa y zinc) indicó una selectividad específica hacia el ácido ascórbico y la ausencia de cualquier respuesta electroquímica hacia estos componentes. Los resultados de recuperación en el rango de 98,93±2,78 - 99,98±5,20 para el ácido ascórbico estándar adicionado en formulaciones farmacéuticas confirmaron además la potencial aplicabilidad del método desarrollado para la determinación del ácido ascórbico en muestras reales. Conclusiones: El método desarrollado se aplicó con éxito al análisis de ácido ascórbico (vitamina C), y los resultados obtenidos coincidieron con los valores etiquetados; además, las pruebas estadísticas no indicaron diferencias significativas a p=0,05 con un nivel de confianza del 95%

Intestinal Tissue Fusion Based on Radiofrequency Energy / 医用生物力学

Objective The ileum of porcine intestines with radiofrequency (RF) energy was fused through a novel linkage-type pressure controlled electrode, so as to verify feasibility and security of intestinal reconstruction in the RF energy tissue fusion technology. Methods Fresh porcine intestines were fixed on negative electrode in the order of ‘mucosa-serosa’, and then different compressive pressures （497，796，995，1 194，1 492 kPa）and RF energy were applied to the tissues through positive electrode of pressure cone to complete intestinal anastomosis. Biomechanical properties of the fused area were studied by tensile strength and bursting pressure test, and the thermal diffusion and tissue microstructure also studied. ResultsThe anastomotic tensile strength and bursting pressure could reach （8.73±1.11） N and （8.29±0.41） kPa, respectively, when the energy output power, pressure and welding time were 160 W, 995 kPa and 13 s, respectively, and an intact microstructure with little free collagen in the fused area could be observed. Conclusions The technology of RF energy-based tissue fusion could accomplish fast and stable intestinal tract reconstruction, showing great potential in clinical application. It is of great significance to shorten the operation time, simplify the operation process and improve the operation quality.

Bi2O3/ZnO nanocomposite:Synthesis,characterizations and its application in electrochemical detection of balofloxacin as an anti-biotic drug / 药物分析学报

In the present work,a chemically modified electrode has been fabricated utilizing Bi2O3/ZnO nano-composite.The nanocomposite was synthesized by simple sonochemical method and characterized for its structural and morphological properties by using XRD,FESEM,EDAX,HRTEM and XPS techniques.The results clearly indicated co-existence of Bi2O3 and ZnO in the nanocomposite with chemical interaction between them.Bi2O3/ZnO nanocomposite based glassy carbon electrode(GCE)was utilized for sensitive voltammetric detection of an anti-biotic drug(balofloxacin).The modification amplified the electroactive surface area of the sensor,thus providing more sites for oxidation of analyte.Cyclic and square wave voltammograms revealed that Bi2O3/ZnO modified electrode provides excellent electrocatalytic action towards balofloxacin oxidation.The current exhibited a wide linear response in concentration range of 150-1000 nM and detection limit of 40.5 nM was attained.The modified electrode offered advantages in terms of simplicity of preparation,fair stability(RSD 1.45％),appreciable reproducibility(RSD 2.03％)and selectivity.The proposed sensor was applied for determining balofloxacin in commercial pharmaceutical formulations and blood serum samples with the mean recoveries of 99.09％and 99.5％,respectively.

Feasibility of using surface electromyography for the detection of abnormal muscle response in patients with hemifacial spasm / 西安交通大学学报(医学版)

【Objective】 To investigate the feasibility of using surface electromyography （SEMG） for the detection of abnormal muscle response （AMR） in patients with hemifacial spasm （HFS）. 【Methods】 We retrospectively reviewed the clinical data of HFS patients who underwent microvascular decompression （MVD） in our hospital between June 2019 and December 2020. Patients who received both surface electrode （preoperative） and needle electrode （intraoperative） detection of AMR were included. SEMG recorded from two stimulation-recording sites， namely， zygomatic-mentalis and mandibular marginal-orbicularis oculi， was selected for analyzing the characteristics of AMR. The positive rates of AMR detected by these two kinds of electrodes were comprehensively compared. 【Results】 Totally 77 patients were included in this study. When detected with surface electrodes， the positive rate， latency and amplitude of AMR recorded at zygomatic-mentalis oculi were 90.9% （70/77）， （10.87±1.86） ms and （202.8±47.4） μV， and at mandibular marginal-orbicularis oculi were 92.2% （71/77）， （10.41±1.83） ms and （211.1±54.1） μV， respectively. AMR was detected in 74 patients （96.1%） with surface electrodes. There was no significant difference in positive rate， latency and amplitude of AMR between these two stimulation-recording methods. When detected with needle electrodes， the positive rate of AMR recorded at zygomatic-mentalis oculi was 98.7% （76/77）， which was significantly higher than the rate 89.6% （69/77） recorded at mandibular marginal-orbicularis oculi （P=0.016）. The latency and amplitude of AMR recorded at zygomatic-mentalis were （10.63±1.39） ms and （83.5±27.2） μV， and at mandibular marginal-orbicularis oculi were （10.31±1.18） ms and （58.6±21.4） μV. There was no significant difference in latency between the two stimulation-recording methods， but the amplitude recorded at mandibular marginal-orbicularis oculi was significantly lower （P=0.041）. AMR was detected in 76 patients （98.7%） with needle electrodes. There was no significant difference in the detection rate of AMR between surface electrodes and needle electrodes （P=0.500）， the results were moderately consistent （Kappa=0.490， P<0.001）. 【Conclusion】 The detection efficiency of surface electrodes for AMR is similar to that of needle electrode. With its non-invasive characteristic， the surface electrode can be routinely used for electrophysiological evaluation of HFS.

Effect of electrode temperature on measurements of transcutaneous carbon dioxide partial pressure and oxygen partial pressure in very low birth weight infants / 中国当代儿科杂志

OBJECTIVES@#To evaluate the accuracy and safety of measurements of transcutaneous carbon dioxide partial pressure (TcPCO@*METHODS@#A total of 45 very low birth weight infants were enrolled. TcPCO@*RESULTS@#There was no significant difference in TcPCO@*CONCLUSIONS@#Lower electrode temperatures (38-41℃) can accurately measure blood carbon dioxide partial pressure in very low birth weight infants, and thus can be used to replace the electrode temperature of 42°C. Transcutaneous measurements at the lower electrode temperatures may be helpful for understanding the changing trend of blood oxygen partial pressure.

Effects of parameters selection with transcranial direct current stimulation based on real head model / 生物医学工程学杂志

Transcranial direct current stimulation (tDCS) is a brain stimulation intervention technique, which has the problem of different criteria for the selection of stimulation parameters. In this study, a four-layer real head model was constructed. Based on this model, the changes of the electric field distribution in the brain with the current intensity, electrode shape, electrode area and electrode spacing were analyzed by using finite element simulation technology, and then the optimal scheme of electrical stimulation parameters was discussed. The results showed that the effective stimulation region decreased and the focusing ability increased with the increase of current intensity. The normal current density of the quadrilateral electrode was obviously larger than that of the circular electrode, which indicated that the quadrilateral electrode was more conducive to current stimulation of neurons. Moreover, the effective stimulation region of the quadrilateral electrode was more concentrated and the focusing ability was stronger. The focusing ability decreased with the increase of electrode area. Specifically, the focusing tended to increase first and then decrease with the increase of electrode spacing and the optimal electrode spacing was 64.0-67.2 mm. These results could provide some basis for the selection of electrical stimulation parameters.