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Electric current spread

Yan Yan, Yiliang Lu, Menghui Li, Zengguang Ma, Pengjia Cao, Yao Chen, Xiaodong Sun, Xinyu Chai, Qiushi Ren, Liming Li
Purpose: Current steering is a neural stimulation strategy that uses simultaneous stimulation of adjacent electrodes to produce additional intermediate stimulation sites and thus improves spatial resolution. We investigated the feasibility of current steering using electrophysiological and computational methods after implanting paired penetrating electrodes into the rabbit's optic nerve (ON). Methods: Penetrating electrodes at different interelectrode distances were implanted into the ON and electrically evoked cortical potentials (EEPs) in V1 recorded with a 6 × 8 array...
November 1, 2016: Investigative Ophthalmology & Visual Science
Ross Morgan, Michael A Colman, Henry Chubb, Gunnar Seemann, Oleg V Aslanidi
Introduction: The genesis of atrial fibrillation (AF) and success of AF ablation therapy have been strongly linked with atrial fibrosis. Increasing evidence suggests that patient-specific distributions of fibrosis may determine the locations of electrical drivers (rotors) sustaining AF, but the underlying mechanisms are incompletely understood. This study aims to elucidate a missing mechanistic link between patient-specific fibrosis distributions and AF drivers. Methods: 3D atrial models integrated human atrial geometry, rule-based fiber orientation, region-specific electrophysiology, and AF-induced ionic remodeling...
2016: Frontiers in Physiology
Serena Fiocchi, Paolo Ravazzani, Alberto Priori, Marta Parazzini
Recent studies have shown that the specific application of transcranial direct current stimulation (tDCS) over the cerebellum can modulate cerebellar activity. In parallel, transcutaneous spinal DC stimulation (tsDCS) was found to be able to modulate conduction along the spinal cord and spinal cord functions. Of particular interest is the possible use of these techniques in pediatric age, since many pathologies and injuries, which affect the cerebellar cortex as well as spinal cord circuits, are diffuse in adults as well as in children...
2016: Frontiers in Human Neuroscience
Ryosuke Tomio, Takenori Akiyama, Masahiro Toda, Takayuki Ohira, Kazunari Yoshida
OBJECTIVE Transcranial motor evoked potential (tMEP) monitoring is popular in neurosurgery; however, the accuracy of tMEP can be impaired by craniotomy. Each craniotomy procedure and changes in the CSF levels affects the current spread. The aim of this study was to investigate the influence of several craniotomies on tMEP monitoring by using C3-4 transcranial electrical stimulation (TES). METHODS The authors used the finite element method to visualize the electric field in the brain, which was generated by TES, using realistic 3D head models developed from T1-weighted MR images...
October 7, 2016: Journal of Neurosurgery
Paulo R F Rocha, Paul Schlett, Ulrike Kintzel, Volker Mailänder, Lode K J Vandamme, Gunther Zeck, Henrique L Gomes, Fabio Biscarini, Dago M de Leeuw
Microelectrode arrays (MEA) record extracellular local field potentials of cells adhered to the electrodes. A disadvantage is the limited signal-to-noise ratio. The state-of-the-art background noise level is about 10 μVpp. Furthermore, in MEAs low frequency events are filtered out. Here, we quantitatively analyze Au electrode/electrolyte interfaces with impedance spectroscopy and noise measurements. The equivalent circuit is the charge transfer resistance in parallel with a constant phase element that describes the double layer capacitance, in series with a spreading resistance...
October 6, 2016: Scientific Reports
Božidar Bratina, Andrej Šorgo, Janez Kramberger, Urban Ajdnik, Lidija Fras Zemljič, Janez Ekart, Riko Šafarič
After a ban on the depositing of untreated sludge in landfills, the sludge from municipal and industrial water-treatment plants can be regarded as a problem. Waste products of the water treatment process can be a problem or an opportunity - a source for obtaining raw materials. In the European Union, raw sludge and fats, oil and grease (FOG) from municipal and industrial wastewater treatment plants (WWTP) cannot be deposited in any natural or controlled environment. For this reason, it must be processed (stabilized, dried) to be used later as a fertilizer, building material, or alternative fuel source suitable for co-incineration in high temperature furnaces (power plants or concrete plants)...
December 1, 2016: Journal of Environmental Management
Emilio Pedrotti, Francesca Bosello, Adriano Fasolo, Anna C Frigo, Ivan Marchesoni, Alfredo Ruggeri, Giorgio Marchini
PURPOSE: To evaluate efficacy and safety of transcutaneous application of electrical current on symptoms and clinical signs of dry eye (DE). METHODS: 27 patients with DE underwent transcutaneous electrostimulation with electrodes placed onto the periorbital region of both eyes and manual stimulation with a hand-piece conductor moved by the operator. Each patient underwent 12 sessions of 22 min spread over 2 months, two sessions per week in the first month and one session per week in the second month...
September 22, 2016: British Journal of Ophthalmology
Andreas Bahmer, Uwe Baumann
HYPOTHESIS: Triphasic pulse stimulation prevents from facial nerve stimulation (FNS) because of a different electromyographic input-output function compared with biphasic pulse stimulation. BACKGROUND: FNS is sometimes observed in cochlear implant users as an unwanted side effect of electrical stimulation of the auditory nerve. The common stimulation applied in current cochlear implant consists of biphasic pulse patterns. Two common clinical remedies to prevent unpleasant FNS caused by activation of certain electrodes are to expand their pulse phase duration or simply deactivate them...
October 2016: Otology & Neurotology
Hae Yu Kim, Yun Jung Hur, Heung-Dong Kim, Kang Min Park, Sung Eun Kim, Tae Gyu Hwang
OBJECTIVE Thalamic stimulation can provoke electroencephalography (EEG) synchronization or desynchronization, which can help to reduce the occurrence of seizures in intractable epilepsy, though the underlying mechanism is not fully understood. Therefore, the authors investigated changes in EEG electrical activity to better understand the seizure-reducing effects of deep brain stimulation (DBS) in patients with intractable epilepsy. METHODS Electrical activation patterns in the epileptogenic brains of 3 patients were analyzed using classical low-resolution electromagnetic tomography analysis recursively applied (CLARA)...
September 16, 2016: Journal of Neurosurgery
Laura Scherer, Stephan Pfister
Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2...
2016: PloS One
Jeremy Marozeau, Colette M McKay
It has been argued that a main limitation of the cochlear implant is the spread of current induced by each electrode, which activates an inappropriately large range of sensory neurons. To reduce this spread, an alternative stimulation mode, the all-polar mode, was tested with five participants. It was designed to activate all the electrodes simultaneously with appropriate current levels and polarities to recruit narrower regions of auditory nerves at specific intracochlear electrode positions (denoted all-polar electrodes)...
2016: Trends in Hearing
Adriana De-La-Rosa Tovar, Prashant K Mishra, Francisco F De-Miguel
We studied how a neuronal circuit composed of two neuron types connected by chemical and electrical synapses maintains constant its integrative capacities as neurons grow. For this we combined electrophysiological experiments with mathematical modeling in pairs of electrically-coupled Retzius neurons from postnatal to adult leeches. The electrically-coupled dendrites of both Retzius neurons receive a common chemical input, which produces excitatory postsynaptic potentials (EPSPs) with varying amplitudes. Each EPSP spreads to the soma, but also crosses the electrical synapse to arrive at the soma of the coupled neuron...
2016: Frontiers in Cellular Neuroscience
Francisco Javier Sanz-Fuentenebro
The process of normalization electroconvulsive therapy (ECT) requires, among other actions, disseminating the latest information on this technique. One of the most complex aspects is the electrical stimulus, whose knowledge should be spread and put into practice. In this paper we review the available information about frequency and number of ECT sessions, and efficacy of each electrode placement. We also present two approaches to determine the ECT charge: stimulus titration versus age-based method; and the limitations of the summary metrics of charge, being necessary to expand our knowledge of the parameters that configure the stimulus: duration, current amplitude frequency and pulse width...
August 25, 2016: Revista de Psiquiatrí́a y Salud Mental
Xin Luo, Ching-Chih Wu
In cochlear implants (CIs), standard partial tripolar (pTP) mode reduces current spread by returning a fraction of the current to two adjacent flanking electrodes within the cochlea. Symmetric electrode spanning (i.e., separating both the apical and basal return electrodes from the main electrode by one electrode) has been shown to increase the pitch of pTP stimuli, when the ratio of intracochlear return current was fixed. To explain the pitch increase caused by symmetric spanning in pTP mode, this study measured the electrical potentials of both standard and symmetrically spanned pTP stimuli on a main electrode EL8 in five CI ears using electrical field imaging (EFI)...
December 2016: Journal of the Association for Research in Otolaryngology: JARO
Sanjay Kumar Upadhyay, Kartik K Iyer, S Rayaprol, P L Paulose, E V Sampathkumaran
The area of research to discover new Li containing materials and to understand their physical properties has been of constant interest due to applications potential for rechargeable batteries. Here, we present the results of magnetic investigations on a Li compound, Li3Ni2RuO6, which was believed to be a ferrimagnet below 80 K. While our neutron diffraction (ND) and isothermal magnetization (M) data support ferrimagnetism, more detailed magnetic studies establish that this ferrimagnetic phase exhibits some features similar to spin-glasses...
2016: Scientific Reports
Hao He, Qixing Zhang, Ran Tu, Luyao Zhao, Jia Liu, Yongming Zhang
The dripping behavior of the molten thermoplastic insulation of copper wire, induced by flame spread under overload currents, was investigated for a better understanding of energized electrical wire fires. Three types of sample wire, with the same polyethylene insulation thickness and different core diameters, were used in this study. First, overload current effects on the transient one-dimensional wire temperature profile were predicted using simplified theoretical analysis; the heating process and equilibrium temperature were obtained...
December 15, 2016: Journal of Hazardous Materials
Shuping Wang, Shui Guan, Jing Wang, Hailong Liu, Tianqing Liu, Xuehu Ma, Zhanfeng Cui
Poly 3,4-ethylenedioxythiophene (PEDOT), a polythiophene derivative, has been proved to be modified by chemical process as biocompatible conductive polymer for biomedical applications. In this study, novel hyaluronic acid (HA)-doped PEDOT nanoparticles were synthesized by the method of chemical oxidative polymerization, then conductive PEDOT-HA/poly(l-lactic acid) (PLLA) composite films were prepared. The physicochemical characteristics and biocompatibility of films were further investigated. FTIR, Raman and EDX analysis demonstrated that HA was successfully doped into PEDOT particles...
August 3, 2016: Journal of Bioscience and Bioengineering
Maria Sancho, Nina C Samson, Bjorn O Hald, Ahmed M Hashad, Sean P Marrelli, Suzanne E Brett, Donald G Welsh
The conducted vasomotor response reflects electrical communication in the arterial wall and the distance signals spread is regulated by three factors including resident ion channels. This study defined the role of inward-rectifying K(+) channels (KIR) in governing electrical communication along hamster cerebral arteries. Focal KCl application induced a vasoconstriction that conducted robustly, indicative of electrical communication among cells. Inhibiting dominant K(+) conductances had no attenuating effect, the exception being Ba(2+) blockade of KIR Electrophysiology and Q-PCR analysis of smooth muscle cells revealed a Ba(2+)-sensitive KIR current comprised of KIR2...
July 27, 2016: Journal of Cerebral Blood Flow and Metabolism
Byeong Ryong Lee, Tae Geun Kim
UNLABELLED: This paper reports the electrical and optical properties of the reduced graphene oxide (RGO)/single-walled carbon nanotube (SWNT) films using various p-type dopants and its application to GaN-based light-emitting diodes. To enhance the current injection and spreading of the RGO/SWNT films on the light-emitting diodes (LEDs), we increased the work function (φ) of the films using chemical doping with AuCl3, poly(3,4-ethylenedioxythiophene) oxidized with poly(4-styrenesulfonate) ( PEDOT: PSS) and MoO3; thereby reduced the Schottky barrier height between the RGO/SWNT films and p-GaN...
June 2016: Journal of Nanoscience and Nanotechnology
Kristin E Spong, Esteban C Rodríguez, R Meldrum Robertson
Spreading depolarization (SD) is characterized by a massive redistribution of ions accompanied by an arrest in electrical activity that slowly propagates through neural tissue. It has been implicated in numerous human pathologies, including migraine, stroke, and traumatic brain injury, and thus the elucidation of control mechanisms underlying the phenomenon could have many health benefits. Here, we demonstrate the occurrence of SD in the brain of Drosophila melanogaster, providing a model system, whereby cellular mechanisms can be dissected using molecular genetic approaches...
September 1, 2016: Journal of Neurophysiology
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