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1.
Article in Chinese | WPRIM | ID: wpr-880467

ABSTRACT

In order to obtain comprehensive brain activity information conveniently in real time, this study designs a portable EEG and blood oxygen synchronous acquisition system for real-time monitoring of brain functional activities. The EEG electrodes filter and amplify the detected EEG signals, and send them to the microprocessor via Bluetooth to analyze the EEG data; the photoelectric probe converts the optical signals into electrical signals, which are amplified and separated, filtered, and AD converted, calculates the brain's oxygenation and blood-red protein (ΔHbO


Subject(s)
Brain , Electrodes , Electroencephalography , Oxygen
2.
Chinese Journal of Biotechnology ; (12): 1139-1154, 2021.
Article in Chinese | WPRIM | ID: wpr-878620

ABSTRACT

Microneedles have been developed rapidly in the field of transdermal administration in the past few decades. In recent years, the development of microelectronics technology has expanded the applications of microneedles by combining with microelectronic systems, especially in biological diagnosis and treatment. Different types of microneedles have been designed to extract blood and tissue fluids for detection, or as electrodes to directly detect blood sugar, melanoma and pH in real-time in vivo, both show good prospects for real-time detection applications. In this paper, we review the design of materials and structure of microelectronic-based microneedles, and discuss their advances in biological diagnosis.


Subject(s)
Administration, Cutaneous , Drug Delivery Systems , Electrodes , Microinjections , Needles
3.
Chinese Journal of Biotechnology ; (12): 361-377, 2021.
Article in Chinese | WPRIM | ID: wpr-878567

ABSTRACT

Exoelectrogenic microorganisms are the research basis of microbial electrochemical technologies such as microbial fuel cells, electrolytic cells and electrosynthesis. However, their applications are restricted in organic degradation, power generation, seawater desalination, bioremediation, and biosensors due to the weak ability of biofilm formation and the low extracellular electron transfer (EET) efficiency between exoelectrogenic microorganisms and electrode. Therefore, engineering optimization of interaction between exoelectrogenic microorganisms and electrode interface recently has been the research focus. In this article, we review the updated progress in strategies for enhancing microbe-electrode interactions based on microbial engineering modifications, with a focus on the applicability and limitations of these strategies. In addition, we also address research prospects of enhancing the interaction between electroactive cells and electrodes.


Subject(s)
Bioelectric Energy Sources , Biofilms , Electrodes , Electron Transport , Electrons
4.
Article in Chinese | WPRIM | ID: wpr-878538

ABSTRACT

Microbial fuel cell (MFC) is a bioelectrochemical device, that enables simultaneous wastewater treatment and energy generation. However, a few issues such as low output power, high ohmic internal resistance, and long start-up time greatly limit MFCs' applications. MFC anode is the carrier of microbial attachment, and plays a key role in the generation and transmission of electrons. High-quality bioelectrodes have developed into an effective way to improve MFC performance. Conjugated polymers have advantages of low cost, high conductivity, chemical stability and good biocompatibility. The use of conjugated polymers to modify bioelectrodes can achieve a large specific surface area and shorten the charge transfer path, thereby achieving efficient biological electrochemical performance. In addition, bacteria can be coated with nano-scale conjugated polymer and effectively transfer the electrons generated by cells to electrodes. This article reviews the recently reported applications of conjugated polymers in microbial fuel cells, focusing on the MFC anode materials modified by conjugated polymers. This review also systematically analyzes the advantages and limitations of conjugated polymers, and how these composite hybrid bioelectrodes solve practical issues such as low energy output, high inner resistance, and long starting time.


Subject(s)
Bacteria , Bioelectric Energy Sources , Electricity , Electrodes , Polymers , Water Purification
5.
Rev. colomb. cardiol ; 27(5): 405-413, sep.-oct. 2020. tab, graf
Article in Spanish | LILACS, COLNAL | ID: biblio-1289250

ABSTRACT

Resumen Introducción: en los procedimientos de extracción de electrodos, la vía femoral se usa cuando la vía superior ha fracasado. Objetivo: describir la incidencia, el éxito, las complicaciones y los predictores de uso de la vía femoral. Métodos: se realizó un análisis de la incidencia del uso de la vía femoral y los factores predictores en pacientes a quienes se les realizó extracción de electrodos entre noviembre de 2011 y noviembre de 2017. Resultados: se incluyeron 85 pacientes, con edad media de 62,36 ± 11,15 años. El 38,9% de los dispositivos eran marcapasos. Se extrajeron 135 electrodos, 59,3% de fijación pasiva. La mediana de tiempo desde el implante fue de 102 (60-174) meses. Se empleó la ruta femoral en el 25,9% de los procedimientos. Se obtuvo éxito clínico en el 92,9% de los pacientes. La extracción no fue exitosa en el 22,7% de los procedimientos cuando se usó la vía femoral, en comparación con el 1,6% cuando se usó la vía superior (p 0,004). La extracción no fue completa en el 36,4% de los procedimientos cuando se empleó la vía femoral en comparación con el 9,5% por vía superior (p 0,007). Los factores que predijeron el empleo de la ruta femoral fueron la presencia de electrodos de fijación pasiva [OR IC 95% 13,69 (3,06-62,5) p 0,001] y el tiempo desde el implante del electrodo [OR IC 95% por cada 10 meses 1,04 (1,00-1,09) p 0,044]. Conclusiones: se empleó la ruta femoral en el 25,9% de los procedimientos. No fue eficaz en el 22,7% de las intervenciones. Los factores que predijeron su utilización fueron la presencia de electrodos de fijación pasiva y el tiempo desde el implante del electrodo.


Abstract Introduction: The femoral route is used in electrode removal procedures when the upper route has failed. Objective: To describe the incidence, success rate, complications and predictive factors for the use of the femoral route. Methods: An analysis was performed on the incidence of use of the femoral route and the predictive factors in patients in whom electrode removal was carried out between November 2011 and November 2017. Results: The study included 85 patients with a mean age of 62.36 ± 11.5 years. Pacemakers made up 38.9% of the devices. A total of 135 electrodes, 59.3% of passive fixation, were removed. The median time since the implant was 102 (60-174) months. The femoral route was used in 25.9% of the procedures. Clinical success was achieved in 92.9% of the patients. The removal was not successful in 22.7% of the procedures when the femoral route was used, compared to 1.6% when the upper route was used (P = .004). The removal was not completed in 36.4% of the procedures when the femoral route was used, compared to 9.5% with the upper route (P = .007). The factors that predicted the use of the femoral route were the presence of passive-fixation electrodes (OR = 13.69: 95% CI; 3.06 - 62.5, P = .001), and the time since the electrodes were implanted (OR = 1.04, 95% CI; 1.00 - 1.09, P = .044, for every 10 months). Conclusions: The femoral route was employed in 25.9% of the procedures. It was not effective in 22.7% of the interventions. The factors that predicted its use were the presence of passive-fixation electrodes and the time since the electrode implant.


Subject(s)
Humans , Male , Middle Aged , Electrodes , Femoral Vein , Incidence , Equipment and Supplies
6.
Rev. cuba. invest. bioméd ; 39(2): e226, abr.-jun. 2020. tab, graf
Article in Spanish | LILACS, CUMED | ID: biblio-1126587

ABSTRACT

Introducción: este artículo presenta la predicción de tres tipos de movimientos básicos de la mano mediante un algoritmo inteligente para extraer características imprescindibles para el reconocimiento de patrones de movimiento a partir del análisis de señales electromiográficas superficiales adquiridas con el dispositivo Myo. Objetivo: reconocer y predecir patrones básicos de movimiento de la articulación del brazo utilizando electromiografía de superficie para aplicarlo sobre un prototipo de prótesis. Métodos: se tomaron datos de 13 estudiantes de 22 y 23 años de la Universidad Politécnica Salesiana, cada uno de los cuales ejecutó tres tipos de agarre: cilíndrico, pinza y pinza planar. Se trabajó con una frecuencia de 10 Hz y se tomaron 5 muestras por tipo de agarre durante 60 segundos. Para el análisis estadístico de los datos se utilizó la herramienta Anova, estableciendo un valor de significancia mayor a 0,65. Resultados: En ciertos voluntarios hay una mayor reacción en el electrodo 1 debido a que su antebrazo es mayor. El tiempo de respuesta para el reconocimiento varía dependiendo del número de variables que se tenga que comparar. Cuando se analiza un solo movimiento es de 2,6 segundos, en cambio, cuando se analizan los 3 movimientos el tiempo de respuesta incrementa a 7,8 segundos por la cantidad de electrodos que se quieran analizar. Conclusiones: la respuesta del sistema propuesto empieza a ser más lenta a medida que se analizan más movimientos a la vez y por tanto, es menos efectiva. El tiempo de ejecución y respuesta de nuestro sistema, en comparación al estado del arte, es más alto, debido a que se utilizan menos métodos de caracterización de la señal. Adicionalemtne, una limitante del proyecto es la frecuencia de muestreo del dispositivo Myo (200Hz)(AU)


Introduction: the paper presents the prediction of three basic hand movement types by means of a smart algorithm to draw characteristics indispensable for identification of movement patterns based on the analysis of surface electromyographic signals obtained with the Myo device. Objective: recognize and predict basic movement patterns of the arm joint using surface electromyography with a view to applying them over a prosthesis prototype. Methods: data were taken from 13 students aged 22 and 23 years from the Salesian Polytechnic University, each of whom performed three types of grasp: cylindrical, pincer and palmar pincer. A 10 Hz frequency was used and 5 samples were taken of each grasp type during 60 seconds. Statistical analysis was performed with the tool ANOVA, establishing a significance value > 0.65. Results: in certain volunteers a greater reaction was observed in electrode 1, due to their larger forearms. Response time for identification varies with the number of variables to be compared. When only one movement is analyzed, response time is 2.6 seconds, but when the three movements are examined it rises to 7.8 seconds by the number of electrodes intended to be studied. Conclusions: the response of the system proposed starts to slow down as more movements are analyzed simultaneously, which makes it less effective. The performance and response time of our system is higher than in state-of-the-art systems, since fewer signal characterization methods are used. On the other hand, a limitation of the project is the sampling frequency of the Myo device (200 Hz)(AU)


Subject(s)
Humans , Male , Young Adult , Prostheses and Implants/standards , Hand Strength/physiology , Electrodes/standards , Electromyography/methods , Hand/physiology
7.
Korean Circulation Journal ; : 420-429, 2020.
Article in English | WPRIM | ID: wpr-816675

ABSTRACT

BACKGROUND AND OBJECTIVES: It is difficult to estimate the depth of the focal source by activation mapping. The present study was performed to demonstrate the usefulness of a simple maneuver in estimating the depth of the focal activation source (S).METHODS: A total of 44 sites (15 shallow, depth<3.5 mm; 29 deep, depth>5.5 mm) were analyzed in 3 canine left ventricles under general anesthesia. A custom-made bipolar needle electrode was used to simulate a focal activation source. A mapping catheter with an electrode tip size of 2 mm, band electrode size of 1 mm, and inter-electrode spacing of 2-10-2 mm was placed at the mapping area. The position of the center of the distal 2 electrodes was kept at the insertion site of the needle electrode. The time interval between distal and proximal electrodes of the mapping catheter (T(tachy)) was measured during needle electrode pacing. The time interval between distal and proximal electrodes (T(pace)) was measured during pacing with distal electrodes of a mapping catheter. Depth index (δ) was defined as T(tachy)/T(pace). Using in vivo data, simulation was performed to evaluate the depth and δ.RESULTS: Ttachy was 24±7.7 ms and 15±5.6 ms for shallow source and deep source simulation, respectively (p<0.001). δ values were 0.86±0.21 and 0.55±0.21 for shallow source and deep source simulation, respectively (p<0.001). According to simulation data, if δ<0.52, the depth of the focal source will be >5.5 mm.CONCLUSIONS: T(tachy) was shorter and δ was smaller for a deep S than for a shallow S.


Subject(s)
Anesthesia, General , Catheters , Electrodes , Heart Ventricles , Myocardium , Needles , Tachycardia, Ventricular
8.
Article in English | WPRIM | ID: wpr-810975

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate a novel radiofrequency ablation (RFA) application utilizing an adjustable electrode for treatment of benign thyroid nodules.MATERIALS AND METHODS: From April 2011 to December 2018, 21 patients underwent RFA treatment on 21 thyroid nodules, utilizing an 18-gauge internally cooled electrode equipped with a size adjustable active tip. The peripheral nodule portions were ablated with the moving-shot technique and a shorter active tip, and the nodule centers were ablated with the fixed technique and a longer active tip. We assessed parameters including characteristics of the treated nodules, use of variablesized active tips, volume reduction rate, therapeutic success rate, and post-procedural complications. The therapeutic success rate was defined as a > 50% volume reduction of the initial nodule volume at the 6- or 12-month follow-up.RESULTS: The treated thyroid nodules were large enough to cause symptoms (mean volume, 29.6 mL). Two types of active tips per session were used for all nodules. The mean volume reduction rate at the last follow-up was 68.3 ± 4.4% and our therapeutic success rate was 90.5%. Both symptoms and cosmetic scores decreased significantly. Minor complications in three patients were recorded during and after the procedure.CONCLUSION: This initial study demonstrated that an adjustable electrode for RFA of benign thyroid nodules effectively and safely resulted in volume reduction.


Subject(s)
Catheter Ablation , Electrodes , Follow-Up Studies , Humans , Thyroid Gland , Thyroid Nodule , Ultrasonography
9.
Journal of Biomedical Engineering ; (6): 1045-1055, 2020.
Article in Chinese | WPRIM | ID: wpr-879235

ABSTRACT

In order to solve the problems of insufficient stimulation channels and lack of stimulation effect feedback in the current electrical stimulation system, a functional array electrode electrical stimulation system with surface electromyography (sEMG) feedback was designed in this paper. Firstly, the effectiveness of the system was verified through


Subject(s)
Electric Stimulation , Electrodes , Electromyography , Feedback , Female , Humans , Male , Neurofeedback
10.
Article in Chinese | WPRIM | ID: wpr-879216

ABSTRACT

In order to accurately implant the brain electrodes of carp robot for positioning and navigation, the three-dimensional model of brain structure and brain electrodes is to be proposed in the study. In this study, the tungsten electrodes were implanted into the cerebellum of a carp with the aid of brain stereotaxic instrument. The brain motor areas were found and their three-dimensional coordinate values were obtained by the aquatic electricity stimulation experiments and the underwater control experiments. The carp brain and the brain electrodes were imaged by 3.0 T magnetic resonance imaging instrument, and the three-dimensional reconstruction of carp brain and brain electrodes was carried out by the 3D-DOCTOR software and the Mimics software. The results showed that the brain motor areas and their coordinate values were accurate. The relative spatial position relationships between brain electrodes and brain tissue, brain tissue and skull surface could be observed by the three-dimensional reconstruction map of brain tissue and brain electrodes which reconstructed the three-dimensional structure of brain. The anatomical position of the three-dimensional reconstructed brain tissue in magnetic resonance image and the relationship between brain tissue and skull surface could be observed through the three-dimensional reconstruction comprehensive display map of brain tissue. The three-dimensional reconstruction model in this study can provide a navigation tool for brain electrodes implantation.


Subject(s)
Animals , Brain/diagnostic imaging , Carps , Electrodes , Electrodes, Implanted , Imaging, Three-Dimensional , Magnetic Resonance Imaging
11.
Article in Chinese | WPRIM | ID: wpr-774184

ABSTRACT

In order to quantitatively evaluate the performance of dry electrode for fabric surface bioelectricity, a set of active measuring devices that can simulate electrocardiosignal has been developed on the basis of passive system by our group. Five Ag/AgCl fabric dry electrodes were selected to test and evaluate the devices. The results show that the deviation ratios of peak time interval of the five electrodes are all less than 1%. The maximum voltage amplitude decay rate is 7.2%, and the noise amplitudes are lower than 0.004 mV. The variable coefficient of peak time offset is less than 8%. The variable coefficient of voltage amplitude is less than 2%. The variable coefficient of noise amplitude is less than 10%. Research shows the devices has good repeatability and stability in measuring the simulated electrocardiosignal. The active measuring devices proposed in this paper can provide a new method for performance evaluation and standard formulation of surface bioelectricity dry electrode.


Subject(s)
Electrodes , Textiles , Wearable Electronic Devices
12.
Article in Chinese | WPRIM | ID: wpr-772496

ABSTRACT

In order to diagnose and evaluate the human spinal lesions through the paravertebral muscles, a paravertebral muscle monitoring system based on surface EMG signals was designed. The system used surface mount electrodes to obtain the surface myoelectric signal (sEMG) of paravertebral muscle. The signal was filtered and amplified by the conditioning circuit. The signal was collected by the microcontroller NRF52832 and was sent to the mobile APP. After the signal was preprocessed by the wavelet threshold denoising algorithm in APP, the time and frequency characteristics of the sEMG signal reflecting the functional state of the muscle were extracted. The calculated characteristic parameters was displayed in real time in the application interface. The experimental results show that the system meets the design requirements in analog signal acquisition, digital processing of signals and calculation of characteristic parameters. The system has certain application value.


Subject(s)
Algorithms , Computers , Electrodes , Electromyography , Humans , Monitoring, Physiologic , Muscle, Skeletal , Signal Processing, Computer-Assisted
13.
Korean Journal of Radiology ; : 1653-1661, 2019.
Article in English | WPRIM | ID: wpr-786366

ABSTRACT

OBJECTIVE: To evaluate the efficacy and safety of radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) in a large population.MATERIALS AND METHODS: Cases of 152 biopsy-proven PTMCs from 133 patients who had undergone RFA for PTMC between May 2008 and January 2017 were included in this study. All patients were either of high surgical risk or refused to undergo surgery. They were followed up for at least 6 months after initial RFA. Ultrasonography (US) and computed tomography were performed to evaluate the PTMC and the presence of neck metastasis before treatment. RFA was conducted using an internally cooled thyroid-dedicated electrode system. Follow-up US was performed at 1 week, and 2, 6, and 12 months, after the initial RFA, and then at every 6–12 months. We evaluated serial changes of ablated tumors, newly developed cancers, lymph node (LN) or distant metastasis and complications.RESULTS: Complete disappearance was found in 91.4% (139/152) of ablated tumors. Among the 13 tumors in patients who did not show complete disappearance, no tumor displayed any regrowth of the residual ablated lesion during the follow-up period. The mean follow-up period was 39 months. During the follow-up period, there were no local recurrence, no LN or distant metastasis, and no newly developed thyroid cancers. No patients were referred to surgery. The overall complication rate was 3% (4/133) of patients, including one voice change. There were no life-threatening complications or procedure-related deaths.CONCLUSION: Our results suggest that RFA is an effective and safe option for treating low-risk PTMC patients who are of high surgical risk or refuse surgery.


Subject(s)
Catheter Ablation , Electrodes , Follow-Up Studies , Humans , Lymph Nodes , Neck , Neoplasm Metastasis , Recurrence , Thyroid Gland , Thyroid Neoplasms , Ultrasonography , Voice
14.
Article in Korean | WPRIM | ID: wpr-786023

ABSTRACT

OBJECTIVES: This study aims to compare the fluoride-release between different fluorine varnish under in vitro experimental conditions.METHODS: In this study, 5 fluoride varnish products distributed in Korea were selected. V-varnish™ (Vericom, Korea: VV), CavityShield™ (3M ESPE, USA: CS), Clinpro™ White varnish™ (3M ESPE, USA: CP), MI Varnish™ (GC, Japan: MI), and Fluor Protector (Ivoclar Vivadent, Liechtenstein: FP). For the in vitro study, 10 mg of each fluoride varnish was thinly applied to the same area of the specimen. The specimen was then immersed in 3 ml of distilled water at consistent intervals to confirm fluoride release. Nine specimens per group were used. Fluoride ion electrodes were used to measure the fluoride concentration of the solution. The Kruskal-Wallis nonparametric test was performed to compare between each experimental group, and the Wilcoxon signed-rank nonparametric test was performed to compare experimental groups over time. The significance level for a Type I error was set at 0.05. All statistical analyses were performed using SPSS 25.0 (IBM Co., Armonk, NY, USA).RESULTS: In vitro experiments showed that the amount of fluoride released from MI was higher than the other groups during the first 12 hours after application. However, the amount of fluoride released from CP and CS was higher than MI as the immersion time increased over 12 and 20 hours, respectively. The fluoride release from FP was the lowest at all measurement points.CONCLUSIONS: The results of this study showed that the remaining fluoride effect from rosin type fluoride varnishes was higher than liquid type fluoride varnishes. There were differences in the residual fluoride concentrations despite each fluoride varnish having the same fluoride content.


Subject(s)
Dental Caries , Electrodes , Fluorides , Fluorides, Topical , Fluorine , Immersion , In Vitro Techniques , Japan , Korea , Liechtenstein , Paint , Water
15.
Journal of Biomedical Engineering ; (6): 1032-1037, 2019.
Article in Chinese | WPRIM | ID: wpr-781831

ABSTRACT

For the researches relating to the biomedical fields such as preparation of drug micro-particulates and biomedical materials coating, according to the modular design concept and combing the piezoelectric micro-jetting technology with electromechanical engineering and automatic control technology, the drug micro-jetting multifunctional system was designed, which included the spraying support subsystem, - motion platform, -axis subsystem and rapid installation subsystem. The drug micro-jetting multifunctional system was run and adjusted. The versatility, rationality and feasibility of this system were validated by the experiments of amoxicillin microcapsule preparation, titanium alloy drug-loaded coating preparation and balloon electrode coating preparation. It was shown that the system can be used as basic platform in multi-disciplinary cross technology research such as biomedical engineering, pharmaceutical engineering and so on.


Subject(s)
Alloys , Drug Delivery Systems , Electrodes , Titanium
16.
Clinical Pain ; (2): 142-146, 2019.
Article in English | WPRIM | ID: wpr-811477

ABSTRACT

This is a case report of the provocative discographic findings before and after focal selective coagulation of the major annular fissure using intradiscal navigable catheter. A 46-year-old woman had a 30-month history of axial low back pain and magnetic resonance imaging findings suspicious for painful L4/5 disc. The provocative discography confirmed painful disc before coagulation. The final electrode tip position in the coagulation procedure was at the largest fissure within the outer annular margin identified through the discography. Six months after the successful coagulation therapy, inadvertently performed discography resulted in decreased pressure rise over time. Neither evoked pain nor change in the integrity of outer annulus as compared with the previous results was reported. Such an interventional method has not been reported previously, and the analytic results suggest that it may be possible to relocate the pressure of the entire nucleus pulposus only by focal selective coagulation of the fissure.


Subject(s)
Catheters , Electrodes , Female , Humans , Low Back Pain , Magnetic Resonance Imaging , Methods , Middle Aged
17.
Article in English | WPRIM | ID: wpr-788771

ABSTRACT

Epilepsy has been known to humankind since antiquity. The surgical treatment of epilepsy began in the early days of neurosurgery and has developed greatly. Many surgical procedures have stood the test of time. However, clinicians treating epilepsy patients are now witnessing a huge tide of change. In 2017, the classification system for seizure and epilepsy types was revised nearly 36 years after the previous scheme was released. The actual difference between these systems may not be large, but there have been many conceptual changes, and clinicians must bid farewell to old terminology. Paradigms in drug discovery are changing, and novel antiseizure drugs have been introduced for clinical use. In particular, drugs that target genetic changes harbor greater therapeutic potential than previous screening-based compounds. The concept of focal epilepsy has been challenged, and now epilepsy is regarded as a network disorder. With this novel concept, stereotactic electroencephalography (SEEG) is becoming increasingly popular for the evaluation of dysfunctioning neuronal networks. Minimally invasive ablative therapies using SEEG electrodes and neuromodulatory therapies such as deep brain stimulation and vagus nerve stimulation are widely applied to remedy dysfunctional epilepsy networks. The use of responsive neurostimulation is currently off-label in children with intractable epilepsy.


Subject(s)
Child , Classification , Deep Brain Stimulation , Drug Discovery , Drug Resistant Epilepsy , Electrodes , Electroencephalography , Epilepsies, Partial , Epilepsy , Humans , Neurons , Neurosurgery , Seizures , Vagus Nerve Stimulation
18.
Article in English | WPRIM | ID: wpr-763005

ABSTRACT

The electroencephalogram (EEG) is a widely used non-invasive method for monitoring the brain. It is based upon placing conductive electrodes on the scalp which measure the small electrical potentials that arise outside of the head due to neuronal action within the brain. Historically this has been a large and bulky technology, restricted to the monitoring of subjects in a lab or clinic while they are stationary. Over the last decade much research eff ort has been put into the creation of “wearable EEG” which overcomes these limitations and allows the long term non-invasive recording of brain signals while people are out of the lab and moving about. This paper reviews the recent progress in this fi eld, with particular emphasis on the electrodes used to make connections to the head and the physical EEG hardware. The emergence of conformal “tattoo” type EEG electrodes is highlighted as a key next step for giving very small and socially discrete units. In addition, new recommendations for the performance validation of novel electrode technologies are given, with standards in this area seen as the current main bottleneck to the wider take up of wearable EEG. The paper concludes by considering the next steps in the creation of next generation wearable EEG units, showing that a wide range of research avenues are present.


Subject(s)
Brain , Electrodes , Electroencephalography , Head , Methods , Neurons , Scalp
19.
Article in English | WPRIM | ID: wpr-719566

ABSTRACT

BACKGROUND: Recently, carbon fibers have been utilized to develop a depth-type microelectrode array for chronic neural recording. Since the diameter of carbon fibers is smaller than the conventional electrodes made of metal wires or microfabricated silicon, the carbon fiber electrodes showed an improved capability for chronic neural recording with less tissue damages. However, the carbon fiber based microelectrodes have a limitation of short insertion depth due to a low stiffness. METHODS: We proposed a carbon fiber based microelectrode array embedded with a mechanical support structure to facilitate the penetration into the deeper brain. The support is made of biodegradable silk fibroin to reduce the reactive tissue responses. The 4-channel carbon fiber based microelectrode arrays were fabricated and accessed in terms of electrochemical impedance, recording capability for 1-month implantation in rat hippocampi. The electrodes with tungsten supports were fabricated and tested as a control group. Immunohistochemical analysis was performed to identify the reactive glial responses. RESULTS: The carbon fiber based electrode arrays with silk supports showed about 2-fold impedance increase 2 weeks after implantation while the number of active electrodes decreased simultaneously. However, after 1 month, the electrode impedance decreased back to its initial value and the percentage of active electrodes also increased above 70%. Immunohistochemical staining clearly showed that the electrodes with silk supports induced less reactive glial responses than that with tungsten supports. CONCLUSION: The proposed carbon fiber based microelectrode array is expected to be used for long-term in vivo neural recording from deep brain regions with the minimized reactive tissue response.


Subject(s)
Animals , Brain , Carbon , Electric Impedance , Electrodes , Fibroins , Microelectrodes , Rats , Silicon , Silk , Tungsten
20.
Article in English | WPRIM | ID: wpr-765948

ABSTRACT

BACKGROUND/AIMS: Motility disorders are common and may affect the entire gastrointestinal (GI) tract but current treatment is limited. Multilocular sensing of GI electrical activity and variable electrical stimulation (ES) is a promising option. The aim of our study is to investigate the effects of adjustable ES on poststimulatory spike activities in 5 GI segments. METHODS: Six acute porcine experiments were performed with direct ES by 4 ES parameter sets (30 seconds, 25 mA, 500 microseconds or 1000 microseconds, 30 Hz or 130 Hz) applied through subserosal electrodes in the stomach, duodenum, ileum, jejunum, and colon. Multi-channel electromyography of baseline and post-stimulatory GI electrical activity were recorded for 3 minutes with hook needle and hook-wire electrodes. Spike activities were algorithmically calculated, visualized in a heat map, and tested for significance by Poisson analysis. RESULTS: Post-stimulatory spike activities were markedly increased in the stomach (7 of 24 test results), duodenum (8 of 24), jejunum (23 of 24), ileum (18 of 24), and colon (5 of 24). ES parameter analysis revealed that 80.0% of the GI parts (all but duodenum) required a pulse width of 1000 microseconds, and 60.0% (all but jejunum and colon) required 130 Hz frequency for maximum spike activity. Five reaction patterns were distinguished, with 30.0% earlier responses (type I), 42.5% later or mixed type responses (type II, III, and X), and 27.5% non-significant responses (type 0). CONCLUSIONS: Multilocular ES with variable ES parameters is feasible and may significantly modulate GI electrical activity. Automated electromyography analysis revealed complex reaction patterns in the 5 examined GI segments.


Subject(s)
Colon , Duodenum , Electric Stimulation , Electrodes , Electromyography , Gastrointestinal Tract , Hot Temperature , Ileum , Jejunum , Needles , Stomach , Theranostic Nanomedicine
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