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Voltage Mapping

Nicole A Hawkins, Nicole J Zachwieja, Alison R Miller, Lyndsey L Anderson, Jennifer A Kearney
A substantial number of mutations have been identified in voltage-gated sodium channel genes that result in various forms of human epilepsy. SCN1A mutations result in a spectrum of severity ranging from mild febrile seizures to Dravet syndrome, an infant-onset epileptic encephalopathy. Dravet syndrome patients experience multiple seizures types that are often refractory to treatment, developmental delays, and elevated risk for SUDEP. The same sodium channel mutation can produce epilepsy phenotypes of varying clinical severity...
October 2016: PLoS Genetics
Jingyi Zhu, Tilo Mathes, Yusaku Hontani, Maxime T A Alexandre, Kee Chua Toh, Peter Hegemann, John T M Kennis
The two Light, Oxygen, and Voltage domains of phototropin are blue-light photoreceptor domains which control various functions in plants and green algae. The key step of the light-driven reaction is the formation of a photoadduct between its FMN chromophore and a conserved cysteine, where the canonical reaction proceeds through the FMN triplet state. Here, complete photoreaction mapping of CrLOV2 from Chlamydomonas reinhardtii phototropin and AsLOV2 from Avena sativa phototropin-1 was realized by ultrafast broadband spectroscopy from femtoseconds to microseconds...
October 21, 2016: Journal of Physical Chemistry Letters
Mariann Gyöngyösi, Georgiana-Aura Giurgea, Bonni Syeda, Silvia Charwat, Beatrice Marzluf, Julia Mascherbauer, Andras Jakab, Abelina Zimba, Márta Sárközy, Noemi Pavo, Heinz Sochor, Senta Graf, Irene Lang, Gerald Maurer, Jutta Bergler-Klein
OBJECTIVE: The long-term (5-year) outcome of early (3-6 weeks after acute myocardial infarction [AMI], BM-MNC Early group) and late (3-4 months after AMI, BM-MNC Late group) combined (percutaneous intramyocardial and intracoronary) delivery of autologous bone marrow mononuclear cells (BM-MNCs) was evaluated in patients with ejection fractions (EF) between 30-45% post-AMI. METHODS: Major adverse cardiac and cerebrovascular events (MACCE) and hospitalization were recorded...
2016: PloS One
Payam Safavi-Naeini, Dreema Zafar-Awan, Hongjian Zhu, Gerardo Zablah, Anand V Ganapathy, Abdi Rasekh, Mohammad Saeed, Joanna Esther Molina Razavi, Mehdi Razavi
INTRODUCTION: Current methods for measuring voltage during radiofrequency (RF) ablation (RFA) necessitate turning off the ablation catheter. If voltage could be accurately read without signal attenuation during RFA, turning off the catheter would be unnecessary, allowing continuous ablation. We evaluated the accuracy of the Thermocool SMARTTOUCH catheter for measuring voltage while RF traverses the catheter. METHODS AND RESULTS: We studied 26 patients undergoing RFA for arrhythmias...
October 20, 2016: Journal of Cardiovascular Electrophysiology
Thomas Sannicolo, David Muñoz-Rojas, Ngoc Duy Nguyen, Stéphane Moreau, Caroline Celle, Jean-Pierre Simonato, Yves Bréchet, Daniel Bellet
Advancement in the science and technology of random metallic nanowire (MNW) networks is crucial for their appropriate integration in many applications, including transparent electrodes for optoelectronics and transparent film heaters. We have recently highlighted the discontinuous activation of efficient percolating pathways (EPPs) for networks having densities slightly above the percolation threshold. Such networks exhibit abrupt drops of electrical resistance when thermal or electrical annealing is performed, giving rise to a "geometrically quantized percolation"...
October 18, 2016: Nano Letters
Claudia Crocini, Cecilia Ferrantini, Raffaele Coppini, Marina Scardigli, Ping Yan, Leslie M Loew, Godfrey Smith, Elisabetta Cerbai, Corrado Poggesi, Francesco S Pavone, Leonardo Sacconi
Current rescue therapies for life-threatening arrhythmias ignore the pathological electro-anatomical substrate and base their efficacy on a generalized electrical discharge. Here, we developed an all-optical platform to examine less invasive defibrillation strategies. An ultrafast wide-field macroscope was developed to optically map action potential propagation with a red-shifted voltage sensitive dye in whole mouse hearts. The macroscope was implemented with a random-access scanning head capable of drawing arbitrarily-chosen stimulation patterns with sub-millisecond temporal resolution allowing precise epicardial activation of Channelrhodopsin2 (ChR2)...
October 17, 2016: Scientific Reports
Yuko Y Inoue, Bharath Ambale-Venkatesh, Nathan Mewton, Gustavo J Volpe, Yoshiaki Ohyama, Ravi K Sharma, Colin O Wu, Chia-Ying Liu, David A Bluemke, Elsayed Z Soliman, João A C Lima, Hiroshi Ashikaga
Purpose To examine the associations of myocardial diffuse fibrosis and scar with surface electrocardiographic (ECG) parameters in individuals free of prior coronary heart disease in four different ethnicities. Materials and Methods This prospective cross-sectional study was approved by the institutional review boards, and all participants gave informed consent. A total of 1669 participants in the Multi-Ethnic Study of Atherosclerosis, or MESA, who were free of prior myocardial infarction underwent both ECG and cardiac magnetic resonance imaging...
October 13, 2016: Radiology
Tomos E Walters, Jonathan M Kalman, Sheila K Patel, Megan Mearns, Elena Velkoska, Louise M Burrell
AIM: Angiotensin converting enzyme 2 (ACE2) is an integral membrane protein whose main action is to degrade angiotensin II. Plasma ACE2 activity is increased in various cardiovascular diseases. We aimed to determine the relationship between plasma ACE2 activity and human atrial fibrillation (AF), and in particular its relationship to left atrial (LA) structural remodelling. METHODS AND RESULTS: One hundred and three participants from a tertiary arrhythmia centre, including 58 with paroxysmal AF (PAF), 20 with persistent AF (PersAF), and 25 controls, underwent clinical evaluation, echocardiographic analysis, and measurement of plasma ACE2 activity...
October 12, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Martin Huemer, Daniel Qaiyumi, Philipp Attanasio, Abdul Parwani, Burkert Pieske, Florian Blaschke, Leif-Hendrik Boldt, Wilhelm Haverkamp, Alexander Wutzler
AIMS: In persistent atrial fibrillation (AF), left atrial low-voltage areas and complex fractionated atrial electrograms (CFAEs) have been thoroughly discussed as critical substrate points for AF perpetuation. Thus, in patients undergoing pulmonary vein isolation, these sites are often considered additional ablation targets. Currently, mapping techniques for these substrate indicators are still under discussion. The aim of this study was to evaluate the impact of different mapping catheters on the detection of low-voltage areas and CFAE...
October 12, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Yong Hee Kim, Gook Hwa Kim, Min Sun Kim, Sang-Don Jung
A Multi-electrode array (MEA) was fabricated with electrodes consisting of iridium oxide (IrOx) electrochemically deposited on nanoporous gold (NPG) to improve the moderate charge injection limit (ca. 1 mC cm-2) of NPG MEA. IrOx was electrodeposited by performing cyclic voltammetry with an IrOx deposition solution. The IrOx was electrodeposited on Au (EIROF/Au) and on NPG (EIROF/NPG) MEA, and the samples were analyzed in terms of the charge injection limit, charge storage capacity (CSC), and electrochemical impedance...
October 13, 2016: Nano Letters
Bingbo Hou, Lihui Zheng, Guodong Niu, Lingmin Wu, Yu Qiao, Wei Sun, Ligang Ding, Gang Chen, Shu Zhang, Reginald Liew, Yan Yao
AIMS: This study was aimed to report the characteristics and treatment of ventricular tachycardia (VT) following surgical treatment of pulmonary stenosis with intact ventricular septum. METHODS AND RESULTS: Five patients underwent radiofrequency catheter ablation for sustained monomorphic left bundle branch block (LBBB) type VT who previously underwent surgical treatment of pulmonary stenosis. Except stimulation, voltage and activation mapping was performed using three-dimensional (3D) electro-anatomic mapping and ablation was applied accordingly...
October 12, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Junhao Lin, Leyre Gomez, Chris de Weerd, Yasufumi Fujiwara, Tom Gregorkiewicz, Kazutomo Suenaga
We investigate the variation of the bandgap energy of single quantum dots of CsPbBr3 inorganic halide perovskite as a function of size and shape, and upon embedding within an ensemble. For that purpose, we make use of valence-loss electron spectroscopy with Z-contrast annular dark-field (ADF) imaging in a state-of-the-art low-voltage monochromatic scanning transmission electron microscope. In the experiment, energy absorption is directly mapped onto individual quantum dots, whose dimensions and location are simultaneously measured to the highest precision...
October 13, 2016: Nano Letters
Byoung Kuk You, Jong Min Kim, Daniel J Joe, Kyounghoon Yang, Youngsoo Shin, Yeon Sik Jung, Keon Jae Lee
Memristor devices based on electrochemical metallization operate through electrochemical formation/dissolution of nanoscale metallic filaments, and they are considered a promising future nonvolatile memory because of their outstanding characteristics over conventional charge-based memories. However, nanoscale conductive paths or filaments precipitated from the redox process of metallic elements are randomly formed inside oxides resulting in unexpected and stochastic memristive switching parameters including the operating voltage and the resistance state...
October 9, 2016: ACS Nano
Nobuo Kunori, Ichiro Takashima
The motor cortex of rats contains two forelimb motor areas; the caudal forelimb area (CFA) and the rostral forelimb area (RFA). Although the RFA is thought to correspond to the premotor and/or supplementary motor cortices of primates, which are higher-order motor areas that receive somatosensory inputs, it is unknown whether the RFA of rats receives somatosensory inputs in the same manner. To investigate this issue, voltage-sensitive dye (VSD) imaging was used to assess the motor cortex in rats following a brief electrical stimulation of the forelimb...
October 7, 2016: European Journal of Neuroscience
Weimin Wang, Qiang Wang, Hao Ren, Wenying Ma, Chuankai Qiu, Zexiang Chen, Bin Fan
A pseudo-three-layer electrostatic repulsive out-of-plane actuator is proposed. It combines the advantages of two-layer and three-layer repulsive actuators, i.e., fabrication requirements and fill factor. A theoretical model for the proposed actuator is developed and solved through the numerical calculation of Schwarz-Christoffel mapping. Theoretical and simulated results show that the pseudo-three-layer actuator offers higher performance than the two-layer and three-layer actuators with regard to the two most important characteristics of actuators, namely, driving force and theoretical stroke...
October 7, 2016: Scientific Reports
Min Sik Park, Insun Park, Yoon-Sok Kang, Dongmin Im, Seok-Gwang Doo
Chemical databases store information such as molecular formulas, chemical structures, and the physical and chemical properties of compounds. Although the massive databases of organic compounds exist, the search of target materials is constrained by a lack of physical and chemical properties necessary for specific applications. With increasing interest in the development of energy storage systems such as high-voltage rechargeable batteries, it is critical to find new electrolytes efficiently. Here we build a search map to screen organic additives and solvents with novel core and functional groups, and thus establish a database of electrolytes to identify the most promising electrolyte for high-voltage rechargeable batteries...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
Thomas Deneux, Amiram Grinvald
Spontaneous internal activity plays a major role in higher brain functions. The question of how it modulates sensory evoked activity and behavior has been explored in anesthetized rodents, cats, monkeys and in behaving human subjects. However, the complementary question of how a brief sensory input modulates the internally generated activity in vivo remains unresolved, and high-resolution mapping of these bidirectional interactions was never performed. Integrating complementary methodologies, at population and single cells levels, we explored this question...
October 5, 2016: Cerebral Cortex
Ivan Tochitsky, Zachary Helft, Victor Meseguer, Russell B Fletcher, Kirstan A Vessey, Michael Telias, Bristol Denlinger, Jonatan Malis, Erica L Fletcher, Richard H Kramer
Azobenzene photoswitches confer light sensitivity onto retinal ganglion cells (RGCs) in blind mice, making these compounds promising candidates as vision-restoring drugs in humans with degenerative blindness. Remarkably, photosensitization manifests only in animals with photoreceptor degeneration and is absent from those with intact rods and cones. Here we show that P2X receptors mediate the entry of photoswitches into RGCs, where they associate with voltage-gated ion channels, enabling light to control action-potential firing...
October 5, 2016: Neuron
Q Wan, R C Masters, D Lidzey, K J Abrams, M Dapor, R A Plenderleith, S Rimmer, F Claeyssens, C Rodenburg
Recently developed detectors can deliver high resolution and high contrast images of nanostructured carbon based materials in low voltage scanning electron microscopes (LVSEM) with beam deceleration. Monte Carlo Simulations are also used to predict under which exact imaging conditions purely compositional contrast can be obtained and optimised. This allows the prediction of the electron signal intensity in angle selective conditions for back-scattered electron (BSE) imaging in LVSEM and compares it to experimental signals...
September 15, 2016: Ultramicroscopy
Tiago Siebert Altavini, Sergio Andres Conde Ocazionez, David Eriksson, Thomas Wunderle, Kerstin Erika Schmidt
Ongoing brain activity exhibits patterns resembling neural ensembles co-activated by stimulation or task performance. Such patterns have been attributed to the brain's functional architecture, e.g. selective long-range connections. Here, we directly investigate the contribution of selective connections between hemispheres to spontaneous and evoked maps in cat area 18 close to the 17/18 border. We recorded voltage-sensitive dye imaging maps and spiking activity while manipulating interhemispheric input by reversibly deactivating corresponding contralateral areas...
September 21, 2016: NeuroImage
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