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https://www.readbyqxmd.com/read/29780962/challenging-aspects-of-contemporary-cochlear-implant-electrode-array-design
#1
REVIEW
Pavel Mistrík, Claude Jolly, Daniel Sieber, Ingeborg Hochmair
Objective: A design comparison of current perimodiolar and lateral wall electrode arrays of the cochlear implant (CI) is provided. The focus is on functional features such as acoustic frequency coverage and tonotopic mapping, battery consumption and dynamic range. A traumacity of their insertion is also evaluated. Methods: Review of up-to-date literature. Results: Perimodiolar electrode arrays are positioned in the basal turn of the cochlea near the modiolus...
December 2017: World Journal of Otorhinolaryngology—Head and Neck Surgery
https://www.readbyqxmd.com/read/29775401/electroencephalographic-signals-during-anesthesia-recorded-from-surface-and-depth-electrodes
#2
Ville Jäntti, Tuomo Ylinen, Narayan Puthanmadam Subramaniyam, Kotoe Kamata, Arvi Yli-Hankala, Pasi Kauppinen, Eila Sonkajärvi
Purpose - Anesthesiologists have increasingly started to use EEG based indexes to estimate the level and type of unconsciousness. However, the physiology and biophysics are poorly understood in anesthesiological literature. Methods - EEG was recorded from electrodes on the surface of head, including scalp, as well as DBS (deep brain stimulation) electrodes implanted deep in the brain. Mathematical modeling with a realistic head model was performed to create illustrative images of the sensitivity of electrode montages...
May 18, 2018: International Journal of Radiation Biology
https://www.readbyqxmd.com/read/29775152/semi-automated-application-for-estimating-subthalamic-nucleus-boundaries-and-optimal-target-selection-for-deep-brain-stimulation-implantation-surgery
#3
John A Thompson, Salam Oukal, Hagai Bergman, Steven Ojemann, Adam O Hebb, Sara Hanrahan, Zvi Israel, Aviva Abosch
OBJECTIVE Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become standard care for the surgical treatment of Parkinson's disease (PD). Reliable interpretation of microelectrode recording (MER) data, used to guide DBS implantation surgery, requires expert electrophysiological evaluation. Recent efforts have endeavored to use electrophysiological signals for automatic detection of relevant brain structures and optimal implant target location. The authors conducted an observational case-control study to evaluate a software package implemented on an electrophysiological recording system to provide online objective estimates for entry into and exit from the STN...
May 18, 2018: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29773789/light-induced-formation-of-partially-reduced-oxygen-species-limits-the-lifetime-of-photosystem-1-based-biocathodes
#4
Fangyuan Zhao, Steffen Hardt, Volker Hartmann, Huijie Zhang, Marc M Nowaczyk, Matthias Rögner, Nicolas Plumeré, Wolfgang Schuhmann, Felipe Conzuelo
Interfacing photosynthetic proteins specifically photosystem 1 (PS1) with electrodes enables light-induced charge separation processes for powering semiartificial photobiodevices with, however, limited long-term stability. Here, we present the in-depth evaluation of a PS1/Os-complex-modified redox polymer-based biocathode by means of scanning photoelectrochemical microscopy. Focalized local illumination of the bioelectrode and concomitant collection of H2 O2 at the closely positioned microelectrode provide evidence for the formation of partially reduced oxygen species under light conditions...
May 17, 2018: Nature Communications
https://www.readbyqxmd.com/read/29771452/cognitive-safety-of-intracranial-electrodes-for-epilepsy
#5
Kimford J Meador, Casey H Halpern, Bruce P Hermann
Two recent articles in Epilepsia have raised concerns about adverse cognitive effects associated with intracranial electrode implantation. However, both studies have important limitations, and their results contrast with studies that report no adverse cognitive effects of intracranial electrodes for diagnosis or neurostimulation in epilepsy. Furthermore, no data are provided on the relative safety of depth electrodes implanted along the longitudinal axis of the hippocampus vs other electrode locations or types of electrodes...
May 17, 2018: Epilepsia
https://www.readbyqxmd.com/read/29759839/short-lasting-episodes-of-torsade-de-pointes-in-the-chronic-atrioventricular-block-dog-model-have-a-focal-mechanism-while-longer-lasting-episodes-are-maintained-by-re-entry
#6
Nele Vandersickel, Alexandre Bossu, Jan De Neve, Albert Dunnink, Veronique M F Meijborg, Marcel A G van der Heyden, Jet D M Beekman, Jacques M T De Bakker, Marc A Vos, Alexander V Panfilov
OBJECTIVES: This study investigated the arrhythmogenic mechanisms responsible for torsade de pointes (TdP) in the chronic atrioventricular block dog model, known for its high susceptibility for TdP. BACKGROUND: The mechanism of TdP arrhythmias has been under debate for many years. Focal activity as well as re-entry have both been mentioned in the initiation and the perpetuation of TdP. METHODS: In 5 TdP-sensitive chronic atrioventricular block dogs, 56 needle electrodes were evenly distributed transmurally to record 240 unipolar local electrograms simultaneously...
December 26, 2017: JACC. Clinical Electrophysiology
https://www.readbyqxmd.com/read/29758512/conjugated-ionic-state-and-its-distribution-in-perylene-bisimide-doped-film-a-characterization-of-z-scanning-in-confocal-raman-spectroscopy
#7
Xuehong Zhou, Wenqiang Zhang, Cong Wang, Jiadong Zhou, Linlin Liu, Zengqi Xie, Yuguang Ma
Ion-doped states are significant for improving the performance in organic semiconductor-based devices, which require clear characterization to understand their relationship with conductivity and charge transporting mechanisms. In this paper, Raman spectroscopy is used to track the evolution of a dianion-anion-neutral mixture in a perylene bisimide (PBI)-doped film under air, with z-scanning carried out in the confocal mode. The precise distribution for the different states along the film depth is realized within 3...
April 27, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29753106/feasibility-of-imaging-evoked-activity-throughout-the-rat-brain-using-electrical-impedance-tomography
#8
Mayo Faulkner, Sana Hannan, Kirill Aristovich, James Avery, David Holder
Electrical Impedance Tomography (EIT) is an emerging technique which has been used to image evoked activity during whisker displacement in the cortex of an anaesthetised rat with a spatiotemporal resolution of 200 μm and 2 ms. The aim of this work was to extend EIT to image not only from the cortex but also from deeper structures active in somatosensory processing, specifically the ventral posterolateral (VPL) nucleus of the thalamus. The direct response in the cortex and VPL following 2 Hz forepaw stimulation were quantified using a 57-channel epicortical electrode array and a 16-channel depth electrode...
May 9, 2018: NeuroImage
https://www.readbyqxmd.com/read/29701454/comparative-analysis-of-aqueous-binders-for-high-energy-li-rich-nmc-as-lithium-ion-cathode-and-the-impact-of-adding-phosphoric-acid
#9
Arefeh Kazzazi, Dominic Bresser, Agnese Birrozzi, Jan von Zamory, Maral Hekmatfar, Stefano Passerini
Even though electrochemically inactive, the binding agent in lithium-ion electrodes contributes substantially to performance metrics like the achievable capacity, rate capability, and cycling stability. Herein, we present an in-depth comparative analysis of three different aqueous binding agents, allowing for the replacement of the toxic N-methyl-2-pyrrolidone (NMP) as processing solvent, for high-energy Li1.2Ni0.16Mn0.56Co0.08O2 (Li-rich NMC or LR-NMC) as potential next generation cathode material. The impact of the binding agents, sodium carboxymethyl cellulose (CMC), sodium alginate (ALG), and commercial TRD202A (TRD), and the related chemical reactions occurring during the electrode coating process on the electrode morphology and cycling performance is investigated...
April 27, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29694942/growth-and-current-production-of-mixed-culture-anodic-biofilms-remain-unaffected-by-sub-microscale-surface-roughness
#10
Mélanie Pierra, Mehdi Golozar, Xu Zhang, Antonin Prévoteau, Michael De Volder, Dominiek Reynaerts, Korneel Rabaey
Bioelectrochemical systems couple electricity demand/supply to the metabolic redox reactions of microorganisms. Generally, electrodes act not only as electron acceptors/donors, but also as physical support for an electroactive biofilm. The microorganism-electrode interface can be modified by changing the chemical and/or topographical features of the electrode surface. Thus far, studies have reported conflicting results on the impact of the electrode surface roughness on the growth and current production of biofilms...
April 12, 2018: Bioelectrochemistry
https://www.readbyqxmd.com/read/29693330/in-situ-biofilm-quantification-in-bioelectrochemical-systems-using-optical-coherence-tomography
#11
Sam Molenaar, Tom Sleutels, Joao Pereira, Matteo Iorio, Casper Borsje, Julian Zamudio, Francisco Fabregat-Santiago, Cees Buisman, Annemiek Ter Heijne
Detailed studying of microbial growth in bioelectrochemical systems is required for their proper design and operation. Here we report on the use of Optical Coherence Tomography (OCT) as a tool for in situ and non-invasive quantification of biofilm growth on electrodes (bioanodes). An experimental platform is designed and described in which transparent electrodes are used to allow for real-time, three-dimensional biofilm imaging. The accuracy and precision of the developed method is assessed by relating OCT results to well-established standards for biofilm quantification (COD and Total N) and show high correspondence to these standards...
April 25, 2018: ChemSusChem
https://www.readbyqxmd.com/read/29687239/the-development-of-a-four-electrode-bio-impedance-sensor-for-identification-and-localization-of-deep-pulmonary-nodules
#12
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
https://www.readbyqxmd.com/read/29685378/cochlear-implants-insertion-assessment-by-computed-tomography
#13
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
https://www.readbyqxmd.com/read/29678186/should-fluid-dynamics-be-included-in-computer-models-of-rf-cardiac-ablation-by-irrigated-tip-electrodes
#14
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
https://www.readbyqxmd.com/read/29667119/a-novel-neural-electrode-with-micro-motion-attenuation-capability-based-on-compliant-mechanisms-physical-design-concepts-and-evaluations
#15
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
https://www.readbyqxmd.com/read/29664645/mesoscopic-elastic-distortions-in-gaas-quantum-dot-heterostructures
#16
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
https://www.readbyqxmd.com/read/29660723/fluoride-prevalence-in-groundwater-around-a-fluorite-mining-area-in-the-flood-plain-of-the-river-swat-pakistan
#17
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
https://www.readbyqxmd.com/read/29645006/hippocampal-depth-electrodes-in-epilepsy-surgery-diagnostic-or-damaging
#18
COMMENT
Daniel L Drane, Robert E Gross
No abstract text is available yet for this article.
March 2018: Epilepsy Currents
https://www.readbyqxmd.com/read/29644947/intracranial-electroencephalographic-monitoring-from-subdural-to-depth-electrodes
#19
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
https://www.readbyqxmd.com/read/29625330/use-of-torsional-resonators-to-monitor-electroactive-biofilms
#20
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
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