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Depth electrode

Rasool Baghbani, Mohammad Hassan Moradi, Mohammad Behgam Shadmehr
Identifying and localizing of deep pulmonary nodules are among the main challenges that thoracic surgeons face during operations, particularly in thoracoscopic procedures. To facilitate this, we have tried to introduce a non-invasive and safe method by measuring the lung electrical bio-impedance spectrum with a four-electrode array sensor. To study the feasibility of this method, since any change in the depth or diameter of the nodule in the lung tissue is not practical, we used the finite element modeling of the lung tissue and pulmonary nodule to allow changes in the depth and diameter of the nodule, as well as the distance in between the injection electrodes...
April 23, 2018: Annals of Biomedical Engineering
Ana Luiza Menegatti Pavan, Allan Felipe Fattori Alves, Guilherme Giacomini, João Maurício Carrasco Altemani, Arthur Menino Castilho, Raquel Andrade Lauria, Vagner Antonio Rodrigues da Silva, Alexandre Caixeta Guimarães, Diana Rodrigues de Pina
BACKGROUND AND OBJECTIVES: Imaging exams play a key role in cochlear implants with regard to both planning implantation before surgery and quality control after surgery. The ability to visualize the three-dimensional location of implanted electrodes is useful in clinical routines for assessing patient outcome. The aim of this study was to evaluate linear and angular insertion depth measurements of cochlear implants based on conventional computed tomography. METHODS: Tools for linear and angular measurements of cochlear implants were used in computed tomography exams...
April 14, 2018: American Journal of Otolaryngology
Ana González-Suárez, Juan J Pérez, Enrique Berjano
BACKGROUND: Although accurate modeling of the thermal performance of irrigated-tip electrodes in radiofrequency cardiac ablation requires the solution of a triple coupled problem involving simultaneous electrical conduction, heat transfer, and fluid dynamics, in certain cases it is difficult to combine the software with the expertise necessary to solve these coupled problems, so that reduced models have to be considered. We here focus on a reduced model which avoids the fluid dynamics problem by setting a constant temperature at the electrode tip...
April 20, 2018: Biomedical Engineering Online
Wenguang Zhang, Jiaqi Tang, Zhengwei Li, Yakun Ma
In order to solve the problem of the short lifespan of the neural electrode caused by micro motion, this study designed a novel neural electrode based on lumped compliance compliant mechanism to control different modes of micro-motion in a more effective way. According to the mathematical modeling of the novel neural electrode, the equivalent bending stiffness and equivalent tensile (compression) stiffness were calculated. The results of the finite element analysis based on the mathematical modeling revealed that the novel neural electrode showed excellent micro-motion-attenuation capability...
April 18, 2018: Medical & Biological Engineering & Computing
Anastasios Pateras, Joonkyu Park, Youngjun Ahn, Jack A Tilka, Martin V Holt, Christian Reichl, Werner Wegscheider, Timothy Baart, Juan Pablo Dehollain, Uditendu Mukhopadhyay, Lieven M K Vandersypen, Paul G Evans
Quantum devices formed in high-electron-mobility semiconductor heterostructures provide a route through which quantum mechanical effects can be exploited on length scales accessible to lithography and integrated electronics. The electrostatic definition of quantum dots in semiconductor heterostructure devices intrinsically involves the lithographic fabrication of intricate patterns of metallic electrodes. The formation of metal/semiconductor interfaces, growth processes associated with polycrystalline metallic layers, and differential thermal expansion produce elastic distortion in the active areas of quantum devices...
April 17, 2018: Nano Letters
Abdur Rashid, Dong-Xing Guan, Abida Farooqi, Sardar Khan, Salman Zahir, Shah Jehan, Seema Anjum Khattak, Muhammad Sufaid Khan, Raees Khan
This study investigated the fluoride (F- ) concentrations and physicochemical parameters of the groundwater in a fluorite mining area of the flood plain region of the River Swat, with particular emphasis on the fate and distribution of F- and the hydrogeochemistry. To better understand the groundwater hydrochemical profile and F- enrichment, groundwater samples (n=53) were collected from shallow (24-40m), mid-depth (48-65m) and deep (85-120m) aquifers, and then analysed using an ion-selective electrode. The lowest F- concentration (0...
April 13, 2018: Science of the Total Environment
Daniel L Drane, Robert E Gross
No abstract text is available yet for this article.
March 2018: Epilepsy Currents
Holger Joswig, David A Steven, Andrew G Parrent, Keith W MacDougall, Seyed M Mirsattari, Richard S McLachlan, David C Diosy, Jorge G Burneo
At the London Health Sciences Centre Epilepsy Program, stereotactically implanted depth electrodes have largely replaced subdural electrodes in the presurgical investigation of patients with drug-resistant epilepsy over the past 4 years. The rationale for this paradigm shift was more experience with, and improved surgical techniques for, stereoelectroencephalography, a possible lower-risk profile for depth electrodes, better patient tolerability, shorter operative time, as well as increased recognition of potential surgical targets that are not accessible to subdural electrodes...
April 12, 2018: Canadian Journal of Neurological Sciences. le Journal Canadien des Sciences Neurologiques
Phillipp Sievers, Christopher Moß, Uwe Schröder, Diethelm Johannsmann
Whereas the study of interfaces and thin films with the quartz crystal microbalance (QCM) is well established, biofilms have proven to be a difficult subject for the QCM. The main problem is that the shear wave emanating from the resonator surface does not usually reach to the top of the sample. This problem can be solved with torsional resonators. These have a resonance frequency in the range of tens of kHz, which is much below the frequency of the thickness-shear QCMs. The depth of penetration of the shear wave is correspondingly larger...
March 22, 2018: Biosensors & Bioelectronics
Ying Meng, Mathew R Voisin, Suganth Suppiah, Zamir Merali, Ali Moghaddamjou, Naif M Alotaibi, Arbelle Manicat-Emo, Shelly Weiss, Cristina Go, Blathnaid McCoy, Elizabeth J Donner, James T Rutka
OBJECTIVE Intracranial electroencephalography (iEEG) monitoring is an important method of identifying the seizure focus in patients with medically refractory epilepsy. While previous studies have demonstrated low rates of surgical complications, reported rates of surgical site infection (SSI) are highly variable. To date, no studies have specifically evaluated the patient or operative risk factors contributing to SSI. The goals of this study were to examine the rate of SSI after iEEG monitoring for epilepsy workup in pediatric patients and to determine the variables that might contribute to the development of SSI...
April 6, 2018: Journal of Neurosurgery. Pediatrics
Minmin Hu, Tao Hu, Zhaojin Li, Yi Yang, Renfei Cheng, Jinxing Yang, Cong Cui, Xiaohui Wang
MXenes, an emerging class of conductive two-dimensional materials, have been regarded as promising candidates in the field of electrochemical energy storage. The electrochemical performance of their representative, Ti3C2Tx, where T stands for the surface termination group of F, O, or OH, strongly relies on termination mediated surface functionalization, but an in-depth understanding of the relationship between them remains unresolved. Here, we studied comprehensively the structural feature and electrochemical performance of two kinds of Ti3C2Tx MXenes obtained by etching Ti3AlC2 precursor in aqueous HF solution with low concentration (6 mol/L) and high concentration of (15 mol/L), respectively...
April 2, 2018: ACS Nano
S Medina Villalon, R Paz, N Roehri, S Lagarde, F Pizzo, B Colombet, F Bartolomei, R Carron, C-G Bénar
BACKGROUND: In pharmacoresistant epilepsy, exploration with depth electrodes can be needed to precisely define the epileptogenic zone. Accurate location of these electrodes is thus essential for the interpretation of Stereotaxic EEG (SEEG) signals. As SEEG analysis increasingly relies on signal processing, it is crucial to make a link between these results and patient's anatomy. Our aims were thus to develop a suite of software tools, called "EpiTools", able to i) precisely and automatically localize the position of each SEEG contact and ii) display the results of signal analysis in each patient's anatomy...
March 29, 2018: Journal of Neuroscience Methods
Kyuman Kim, Seoungwoo Byun, Jaecheol Choi, Seungbum Hong, Myung-Hyun Ryou, Yong Min Lee
Polymeric binder distribution within electrodes is crucial to guarantee the electrochemical performance of lithium-ion batteries (LIBs) for their long-term use in applications such as electric vehicles and energy storage systems. However, due to the limited analytical tools, such analyses have not been conducted. Thus, the adhesion properties of LIB electrodes at different depths are measured in this work by using a surface and interfacial cutting analysis system (SAICAS). Moreover, two LiCoO2 electrodes dried at 130 and 230°C are carefully prepared and used to obtain the adhesion properties at every 10 µm of depth as well as the interface between the electrode composite and the current collector...
March 30, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Duaa M Ba-Armah, Elizabeth J Donner, Ayako Ochi, Cristina Go, Bláthnaid McCoy, Carter Snead, James Drake, Kevin C Jones
SUDEP is the sudden unexpected death of a person with epilepsy, when no structural or toxicological cause of death can be found. The majority of witnessed cases are reported to be preceded by a convulsive seizure and postictal hypoventilation. Here, we report an 8-year-old girl with drug-resistant focal seizures secondary to a focal cortical dysplasia type IIb. While undergoing invasive intracranial monitoring with subdural and depth electrodes, she had a clinical apnea event recorded on video, followed by bradycardia, which required resuscitation...
March 2018: Epilepsia open
Guy Rozen, Leon M Ptaszek, Israel Zilberman, Victoria Douglas, E Kevin Heist, Christopher Beeckler, Andres Altmann, Jeremy N Ruskin, Assaf Govari, Moussa Mansour
Aims: Delivery of high-power short-duration radiofrequency (RF) ablation lesions is not commonly used, in part because conventional thermocouple (TC) technology underestimates tissue temperature, increasing the risk of steam pop, and thrombus formation. We aimed to test whether utilization of an ablation catheter equipped with a highly accurate novel TC technology could facilitate safe and effective delivery of high-power RF lesions. Methods and results: Adult male Yorkshire swine were used for the study...
March 22, 2018: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Jayant Charthad, Ting Chia Chang, Zhaokai Liu, Ahmed Sawaby, Marcus J Weber, Sam Baker, Felicity Gore, Stephen A Felt, Amin Arbabian
A wireless electrical stimulation implant for peripheral nerves, achieving >10× improvement over state of the art in the depth/volume figure of merit, is presented. The fully integrated implant measures just 2 mm × 3 mm × 6.5 mm (39 mm3 , 78 mg), and operates at a large depth of 10.5 cm in a tissue phantom. The implant is powered using ultrasound and includes a miniaturized piezoelectric receiver (piezo), an IC designed in 180 nm HV BCD process, an off-chip energy storage capacitor, and platinum stimulation electrodes...
April 2018: IEEE Transactions on Biomedical Circuits and Systems
Douglas McCreery, Kamal Yadev, Martin Han
Auditory brainstem implants (ABIs) can restore useful hearing to persons with deafness who cannot benefit from cochlear implants. However, the quality of hearing restored by ABIs rarely is comparable to that provided by cochlear implants in persons for whom those are appropriate. In an animal model, we evaluated elements of a prototype of an ABI in which the functions of macroelectrodes on the surface of the dorsal cochlear nucleus would be integrated with the function of multiple penetrating microelectrodes implanted into the ventral cochlear nucleus...
March 9, 2018: Hearing Research
Chao-Ching Ho, Dung-Sheng Wu
Spark-assisted chemical engraving (SACE) is a non-traditional machining technology that is used to machine electrically non-conducting materials including glass, ceramics, and quartz. The processing accuracy, machining efficiency, and reproducibility are the key factors in the SACE process. In the present study, a machine vision method is applied to monitor and estimate the status of a SACE-drilled hole in quartz glass. During the machining of quartz glass, the spring-fed tool electrode was pre-pressured on the quartz glass surface to feed the electrode that was in contact with the machining surface of the quartz glass...
March 22, 2018: Materials
Xin Liu, Yichen Lu, Ege Iseri, Yuhan Shi, Duygu Kuzum
Electrophysiology is a decades-old technique widely used for monitoring activity of individual neurons and local field potentials. Optogenetics has revolutionized neuroscience studies by offering selective and fast control of targeted neurons and neuron populations. The combination of these two techniques is crucial for causal investigation of neural circuits and understanding their functional connectivity. However, electrical artifacts generated by light stimulation interfere with neural recordings and hinder the development of compact closed-loop systems for precise control of neural activity...
2018: Frontiers in Neuroscience
Sarah Schnitzler, Christian Johannes Hartmann, Stefan Jun Groiss, Lars Wojtecki, Alfons Schnitzler, Jan Vesper, Jan Hirschmann
OBJECTIVE: To assess whether high frequency oscillations (HFOs, >150 Hz), known to occur in basal ganglia nuclei, can be observed in the thalamus. METHODS: We recorded intraoperative local field potentials from the ventral intermediate nucleus (VIM) of the thalamus in patients with Essential Tremor (N = 16), Parkinsonian Tremor (3), Holmes Tremor (2) and Dystonic Tremor (1) during implantation of electrodes for deep brain stimulation. Recordings were performed with up to five micro/macro-electrodes that were simultaneously advanced to the stereotactic target...
February 19, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
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