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https://www.readbyqxmd.com/read/28798342/nanoparticle-based-plasmonic-transduction-for-modulation-of-electrically-excitable-cells
#1
Parveen Bazard, Robert D Frisina, Joseph P Walton, Venkat R Bhethanabotla
There is a compelling need for the development of new sensory and neural prosthetic devices which are capable of more precise point stimulation. Current prosthetic devices suffer from the limitation of low spatial resolution due to the non-specific stimulation characteristics of electrical stimulation, i.e., the spread of electric fields generated. We present a visible light stimulation method for modulating the firing patterns of electrically-excitable cells using surface plasmon resonance phenomena. In in-vitro studies using gold (Au) nanoparticle-coated nanoelectrodes, we show that this method (substrate coated with nanoparticles) has the potential for incorporating this new technology into neural stimulation prosthetics, such as cochlear implants for the deaf, with very high spatial resolution...
August 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28755756/brain-extracellular-space-the-final-frontier-of%C3%A2-neuroscience
#2
REVIEW
Charles Nicholson, Sabina Hrabětová
Brain extracellular space is the narrow microenvironment that surrounds every cell of the central nervous system. It contains a solution that closely resembles cerebrospinal fluid with the addition of extracellular matrix molecules. The space provides a reservoir for ions essential to the electrical activity of neurons and forms an intercellular chemical communication channel. Attempts to reveal the size and structure of the extracellular space using electron microscopy have had limited success; however, a biophysical approach based on diffusion of selected probe molecules has proved useful...
July 26, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28754993/neurometabolic-and-electrophysiological-changes-during-cortical-spreading-depolarization-multimodal-approach-based-on-a-lactate-glucose-dual-microbiosensor-arrays
#3
Cátia F Lourenço, Ana Ledo, Greg A Gerhardt, João Laranjinha, Rui M Barbosa
Spreading depolarization (SD) is a slow propagating wave of strong depolarization of neural cells, implicated in several neuropathological conditions. The breakdown of brain homeostasis promotes significant hemodynamic and metabolic alterations, which impacts on neuronal function. In this work we aimed to develop an innovative multimodal approach, encompassing metabolic, electric and hemodynamic measurements, tailored but not limited to study SD. This was based on a novel dual-biosensor based on microelectrode arrays designed to simultaneously monitor lactate and glucose fluctuations and ongoing neuronal activity with high spatial and temporal resolution...
July 28, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28700446/pure-tone-masking-patterns-for-monopolar-and-phantom-electrical-stimulation-in-cochlear-implants
#4
Aniket A Saoji, Kanthaiah Koka, Leonid M Litvak, Charles C Finley
OBJECTIVES: Monopolar stimulation of the most apical electrode produces the lowest pitch sensation in cochlear implants clinically. A phantom electrode that uses out-of-phase electrical stimulation between the most apical and the neighboring basal electrode can produce a lower pitch sensation than that associated with the most apical electrode. However, because of the absence of contacts beyond the apical tip of the array, the ability to assess the spread of electrical excitation associated with phantom stimulation is limited in the typical cochlear implant subject with no residual hearing...
July 11, 2017: Ear and Hearing
https://www.readbyqxmd.com/read/28698652/electrical-properties-of-graphene-metal-contacts
#5
Teresa Cusati, Gianluca Fiori, Amit Gahoi, Vikram Passi, Max C Lemme, Alessandro Fortunelli, Giuseppe Iannaccone
The performance of devices and systems based on two-dimensional material systems depends critically on the quality of the contacts between 2D material and metal. A low contact resistance is an imperative requirement to consider graphene as a candidate material for electronic and optoelectronic devices. Unfortunately, measurements of contact resistance in the literature do not provide a consistent picture, due to limitations of current graphene technology, and to incomplete understanding of influencing factors...
July 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28685578/vital-role-of-oxygen-for-the-formation-of-highly-rectifying-schottky-barrier-diodes-on-amorphous-zinc-tin-oxide-with-various-cation-compositions
#6
Sofie Bitter, Peter Schlupp, Holger von Wenckstern, Marius Grundmann
We present electrical properties of Schottky barrier diodes on room-temperature deposited amorphous zinc-tin-oxide (ZTO) with Zn/(Zn + Sn) contents between 0.12 and 0.72. A combinatorial approach with continuous composition spread pulsed laser deposition is used to achieve the wide range of compositions with four samples each on 50 × 50 mm(2) glass substrates. The Schottky barrier contacts were fabricated by the reactive direct-current sputtering of platinum. Best diode properties (rectification ratio SV = 2...
August 9, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28671809/aln-ito-based-hybrid-electrodes-with-conducting-filaments-their-application-to-ultraviolet-light-emitting-diodes
#7
Kyeong Heon Kim, Tae Ho Lee, Tae Geun Kim
A hybrid-type transparent conductive electrode (H-TCE) structure comprising an AlN rod array with conducting filaments (CFs) and indium tin oxide (ITO) films is proposed to improve both current injection and distribution as well as optical transmittance in the UV region. These CFs, generated in UV-transparent AlN rod areas using an electric field, can be used as conducting paths for carrier injection from a metal to a semiconductor such as p-(Al)GaN, which allows perfect Ohmic behavior with high transmittance (>95% at 365 nm) to be obtained...
July 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28652411/saturation-in-phosphene-size-with-increasing-current-levels-delivered-to-human-visual-cortex
#8
William H Bosking, Ping Sun, Muge Ozker, Xiaomei Pei, Brett L Foster, Michael S Beauchamp, Daniel Yoshor
Electrically stimulating early visual cortex results in a visual percept known as a phosphene. Although phosphenes can be evoked by a wide range of electrode sizes and current amplitudes, they are invariably described as small. To better understand this observation, we electrically stimulated 93 electrodes implanted in the visual cortex of 13 human subjects who reported phosphene size while stimulation current was varied. Phosphene size increased as the stimulation current was initially raised above threshold, but then rapidly reached saturation...
July 26, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28642698/enhanced-working-memory-binding-by-direct-electrical-stimulation-of-the-parietal-cortex
#9
Agustina Birba, Eugenia Hesse, Lucas Sedeño, Ezequiel P Mikulan, María Del C García, Juan Ávalos, Federico Adolfi, Agustina Legaz, Tristán A Bekinschtein, Máximo Zimerman, Mario Parra, Adolfo M García, Agustín Ibáñez
Recent works evince the critical role of visual short-term memory (STM) binding deficits as a clinical and preclinical marker of Alzheimer's disease (AD). These studies suggest a potential role of posterior brain regions in both the neurocognitive deficits of Alzheimer's patients and STM binding in general. Thereupon, we surmised that stimulation of the posterior parietal cortex (PPC) might be a successful approach to tackle working memory deficits in this condition, especially at early stages. To date, no causal evidence exists of the role of the parietal cortex in STM binding...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28628917/anatomical-characteristics-of-facial-nerve-and-cochlea-interaction
#10
Nadine Schart-Morén, Sune Larsson, Helge Rask-Andersen, Hao Li
OBJECTIVE: The aim was to study the relationship between the labyrinthine portion (LP) of the facial canal and the cochlea in human inner ear molds and temporal bones using micro-CT and 3D rendering. A reduced cochlea-facial distance may spread electric currents from the cochlear implant to the LP and cause facial nerve stimulation. Influencing factors may be the topographic anatomy and otic capsule properties. METHODS: An archival collection of human temporal bones underwent micro-CT and 3D reconstruction...
2017: Audiology & Neuro-otology
https://www.readbyqxmd.com/read/28613412/myoendothelial-coupling-through-cx40-contributes-to-edh-induced-vasodilation-in-murine-renal-arteries-evidence-from-experiments-and-modelling
#11
Jens Christian Brasen, Cor de Wit, Charlotte Mehlin Sorensen
Regulation of renal vascular resistance plays a major role in controlling arterial blood pressure. The endothelium participates in this regulation as endothelial derived hyperpolarization plays a significant role in smaller renal arteries and arterioles but the exact mechanisms are still unknown AIM: to investigate the role of vascular gap junctions and potassium channels in the renal endothelial derived hyperpolarization. METHODS: in interlobar arteries from wild-type and connexin40 knock-out mice we assessed the role of calcium activated small (SK) and intermediate (IK) conductance potassium channels...
June 14, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/28590508/pyramidal-tract-activation-due-to-subthalamic-deep-brain-stimulation-in-parkinson-s-disease
#12
Philipp Mahlknecht, Harith Akram, Dejan Georgiev, Elina Tripoliti, Joseph Candelario, Andre Zacharia, Ludvic Zrinzo, Jonathan Hyam, Marwan Hariz, Thomas Foltynie, John C Rothwell, Patricia Limousin
BACKGROUND: Subthalamic deep brain stimulation (STN-DBS) is an effective treatment for Parkinson's disease (PD), but can have side effects caused by stimulus spread to structures outside the target volume such as the pyramidal tract. OBJECTIVES: To assess the relevance of pyramidal tract activation with STN-DBS in PD. METHODS: In a multimodal, blinded study in 20 STN-DBS patients, we measured stimulation thresholds for evoking electromyographic activity in orbicularis oris and first dorsal interosseous muscles at each of 150 electrode sites...
June 7, 2017: Movement Disorders: Official Journal of the Movement Disorder Society
https://www.readbyqxmd.com/read/28544556/electrophysiological-analysis-of-synaptic-transmission-in-drosophila
#13
REVIEW
Maria Bykhovskaia, Alexander Vasin
Synaptic transmission is dynamic, plastic, and highly regulated. Drosophila is an advantageous model system for genetic and molecular studies of presynaptic and postsynaptic mechanisms and plasticity. Electrical recordings of synaptic responses represent a wide-spread approach to study neuronal signaling and synaptic transmission. We discuss experimental techniques that allow monitoring synaptic transmission in Drosophila neuromuscular and central systems. Recordings of synaptic potentials or currents at the larval neuromuscular junction (NMJ) are most common and provide numerous technical advantages due to robustness of the preparation, large and identifiable muscles, and synaptic boutons which can be readily visualized...
May 24, 2017: Wiley Interdisciplinary Reviews. Developmental Biology
https://www.readbyqxmd.com/read/28540959/self-assembled-indium-tin-oxide-nanoball-embedded-omnidirectional-reflectors-for-high-photon-extraction-efficiency-in-iii-nitride-ultraviolet-emitters
#14
Semi Oh, Kwang Jae Lee, Sang-Jo Kim, Kab Ha, Jongyeul Jeong, Dongjun Kim, Kyoung-Kook Kim, Seong-Ju Park
The control of the refractive index and electrical conductivity in the dielectric layer of omnidirectional reflectors (ODRs) is essential to improve the low efficiency of AlGaN-based UV emitters. Here, we report self-assembled indium tin oxide (ITO) nanoball-embedded omnidirectional reflectors (NODRs) for use in high-efficiency AlGaN-based UV emitters at 365 nm. These NODRs consisted of a reflective Al layer, a self-assembled conducting ITO nanoball layer for current injection and spreading, and nanovoids that provided a low refractive index to achieve highly efficient UV emitters...
June 8, 2017: Nanoscale
https://www.readbyqxmd.com/read/28488873/removal-of-differential-capacitive-interferences-in-fast-scan-cyclic-voltammetry
#15
Justin A Johnson, Caddy N Hobbs, R Mark Wightman
Due to its high spatiotemporal resolution, fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes enables the localized in vivo monitoring of subsecond fluctuations in electroactive neurotransmitter concentrations. In practice, resolution of the analytical signal relies on digital background subtraction for removal of the large current due to charging of the electrical double layer as well as surface faradaic reactions. However, fluctuations in this background current often occur with changes in the electrode state or ionic environment, leading to nonspecific contributions to the FSCV data that confound data analysis...
June 6, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28480646/amplitude-modulation-based-electrical-stimulation-for-encoding-multipixel-spatiotemporal-visual-information-in-retinal-neural-activities
#16
Sang Baek Ryu, Jeong Woo Choi, Kun No Ahn, Yong Sook Goo, Kyung Hwan Kim
Retinal implants have been developed as a promising way to restore partial vision for the blind. The observation and analysis of neural activities can offer valuable insights for successful prosthetic electrical stimulation. Retinal ganglion cell (RGC) activities have been investigated to provide knowledge on the requirements for electrical stimulation, such as threshold current and the effect of stimulation waveforms. To develop a detailed 'stimulation strategy' for faithful delivery of spatiotemporal visual information to the brain, it is essential to examine both the temporal and spatial characteristics of RGC responses, whereas previous studies were mainly focused on one or the other...
June 2017: Journal of Korean Medical Science
https://www.readbyqxmd.com/read/28430533/new-directions-in-the-rational-design-of-electrical-and-magnetic-seizure-therapies-individualized-low-amplitude-seizure-therapy-ilast-and-magnetic-seizure-therapy-mst
#17
Thomas Radman, Sarah H Lisanby
Electroconvulsive therapy remains a key treatment option for severe cases of depression, but undesirable side-effects continue to limit its use. Innovations in the design of novel seizure therapies seek to improve its risk benefit ratio through enhanced control of the focality of stimulation. The design of seizure therapies with increased spatial precision is motivated by avoiding stimulation of deep brain structures implicated in memory retention, including the hippocampus. The development of two innovations in seizure therapy-individualized low-amplitude seizure therapy (iLAST) and magnetic seizure therapy (MST), are detailed...
April 21, 2017: International Review of Psychiatry
https://www.readbyqxmd.com/read/28422194/field-induced-anomalous-spreading-oscillation-ejection-spinning-and-breaking-of-oil-droplets-on-a-strongly-slipping-water-surface
#18
Sunny Kumar, Bhaskarjyoti Sarma, Ahsok Kumar Dasmahapatra, Amaresh Dalal, Dipankar Narayan Basu, Dipankar Bandyopadhyay
Application of an electric field on an oil droplet floating on the surface of a deionized water bath showed interesting motions such as spreading, oscillation, and ejection. The electric field was generated by connecting a pointed platinum cathode at the top of the oil droplet and a copper anode coated with polymer at the bottom of the water layer. The experimental setup mimicked a conventional electrowetting setup with the exception that the oil was spread on a soft and deformable water isolator. While at relatively lower field intensities we observed spreading of the droplet, at intermediate field intensities the droplet oscillated around the platinum cathode, before ejecting out at a speed as high as ∼5 body lengths per second at even stronger field intensities...
July 1, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28352002/optimisation-of-current-injection-protocol-based-on-a-region-of-interest
#19
Mayo Faulkner, Markus Jehl, Kirill Aristovich, James Avery, Anna Witkowska-Wrobel, David Holder
Electrical Impedance Tomography has the potential to image fast neural activity associated with physiological or epileptic activity throughout the brain. These applications pose a particular challenge as expected voltage changes on the electrodes are less than 1% and geometrical constraints of the body under investigation mean that electrodes can not be evenly distributed around its boundary. Unlike other applications, however, information regarding the location of expected activity is typically available. An informative method for choosing current paths that maximise sensitivity to specific regions is desirable...
March 29, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28334303/characterization-of-direct-current-electrical-penetration-graph-waveforms-and-correlation-with-the-probing-behavior-of-matsumuratettix-hiroglyphicus-hemiptera-cicadellidae-the-insect-vector-of-sugarcane-white-leaf-phytoplasma
#20
J Roddee, Y Kobori, H Yorozuya, Y Hanboonsong
The leafhopper Matsumuratettix hiroglyphicus (Matsumura) (Hemiptera: Cicadellidae) is an important vector of phytoplasma causing white leaf disease in sugarcane. Thus, the aim of our study was to understand and describe the stylet-probing activities of this vector while feeding on sugarcane plants, by using direct current (DC) electrical penetration graph (EPG) monitoring. The EPG signals were classified into six distinct waveforms, according to amplitude, frequency, voltage level, and electrical origin of the observed traces during stylet penetration into the host plant tissues (probing)...
June 1, 2017: Journal of Economic Entomology
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