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Voltage Mapping

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https://www.readbyqxmd.com/read/28541417/family-history-of-atrial-fibrillation-as-a-predictor-of-atrial-substrate-and-arrhythmia-recurrence-in-patients-undergoing-atrial-fibrillation-catheter-ablation
#1
Sunil Kapur, Saurabh Kumar, Roy M John, William G Stevenson, Usha B Tedrow, Bruce A Koplan, Laurence M Epstein, Calum A MacRae, Gregory F Michaud
Aims: A commonly held notion is that patients with a family history of atrial fibrillation (AF) have worse atrial substrate and higher rates of arrhythmia recurrence following ablation. We sought to examine differences in atrial substrate and catheter ablation outcomes in patients with a 1st degree family member with paroxysmal or persistent AF (PeAF) compared to those without. Methods and results: A total of 256 consecutive patients undergoing their 1st ablation for AF (123 paroxysmal, 133 persistent) with >1 year follow up were included...
May 24, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28541250/plasmonic-surface-nanostructuring-of-au-dots-sio2-via-laser-irradiation-induced-dewetting
#2
Ruixuan Yu, Tamaki Shibayama, Junya Ishioka, Xuan Meng, Yanhua Lei, Seiichi Watanabe
The in-situ observation of Au dot formation and the self-assembly dynamics of Au nanoparticles (NPs) was successfully demonstrated via dewetting of Au thin films on SiO<sub>2</sub> glass substrates under nano-second pulsed laser irradiation using a multi-quantum beam high-voltage electron microscope. Moreover, using electron energy-loss spectroscopy (EELS) performed in a scanning transmission electron microscope (STEM), the plasmonic properties of the formed Au/SiO<sub>2</sub> nanostructure were analyzed to demonstrate its validity in advanced optical devices...
May 25, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28536891/myocardial-voltage-ratio-in-arrhythmogenic-right-ventricular-dysplasia-cardiomyopathy
#3
REVIEW
Andreas Müssigbrodt, Livio Bertagnolli, Elena Efimova, Jedrzej Kosiuk, Borislav Dinov, Kerstin Bode, Simon Kircher, Nikolaos Dagres, Michael Döring, Sergio Richter, Philipp Sommer, Daniela Husser, Andreas Bollmann, Gerhard Hindricks, Arash Arya
AIMS: This study aimed to analyze the influence of scar distribution between the endocardium and the epicardium in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). METHODS: Electroanatomical mapping data were derived from our ARVD/C registry. Myocardial voltage distribution between the endocardium and the epicardium was analyzed in 28 patients (18 men, 49.9 ± 13.0 years) with previous ventricular tachycardia (VT) ablation and complete right ventricular maps...
May 23, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/28507904/electroanatomical-voltage-mapping-of-atrial-mahaim-potentials-to-guide-catheter-ablation
#4
Hiroko Asakai, Laura Fenwick, Robert M Hamilton
No abstract text is available yet for this article.
November 2016: HeartRhythm Case Reports
https://www.readbyqxmd.com/read/28505846/traveling-waves-and-worms-in-ac-driven-electroconvection-under-external-multiplicative-noise
#5
Jong-Hoon Huh
In the presence of external multiplicative noise, ac-driven electroconvection (EC) in a nematic liquid crystal is investigated. Noise-induced traveling waves (TWs) including localized ones (worms) are found with a typical, stationary wave. Three kinds of TWs are classified by their dynamic features (e.g., noise-intensity-dependent Hopf frequency and space-time map). Moreover, ac frequency-dependent threshold voltages of EC are examined in high noise intensities causing abnormal charge redistribution of the EC cell, and the roles of ac and noise fields with respect to TWs are elucidated in successive pattern evolutions...
April 2017: Physical Review. E
https://www.readbyqxmd.com/read/28504937/ultrasonic-fingerprint-sensor-with-transmit-beamforming-based-on-a-pmut-array-bonded-to-cmos-circuitry
#6
Xiaoyue Jiang, Hao-Yen Tang, Yipeng Lu, Eldwin Ng, Julius Tsai, Bernhard Boser, David Horsley
In this paper, we present a single-chip 65x42 element ultrasonic pulse-echo fingerprint sensor with transmit beamforming based on piezoelectric micromachined ultrasonic transducers (PMUTs) directly bonded to a CMOS readout ASIC. The readout ASIC was realized in a standard 180 nm CMOS process with a 24V high voltage transistor option. Pulse-echo measurements are performed column-by-column in sequence using either one column or five columns to transmit the ultrasonic pulse at 20 MHz. Transmit beamforming is used to focus the ultrasonic beam at the imaging plane where the finger is located, increasing the ultrasonic pressure and narrowing the 3dB beam-width to 50 microns, a factor of 6...
May 11, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28496076/-early-results-of-complex-fractionated-atrial-electrogram-mapping-guided-atrial-fibrillation-surgery
#7
Kazuaki Fukahara, Mari Sakai, Shigeki Yokoyama, Toshio Doi, Naoki Yoshimura
OBJECTIVE: Although the Cox-maze operation is the standard surgical procedure for permanent atrial fibrillation(AF), conversion to sinus rhythm is limited by patient characteristics, including the duration of AF, atrial size, and voltage of fibrillation waves. A surgical strategy based on structural alteration of the electrical substrates of AF is required to achieve better outcomes of AF surgery. Complex fractionated atrial electrogram (CFAE) plays an important role in the electrical substrate of AF...
May 2017: Kyobu Geka. the Japanese Journal of Thoracic Surgery
https://www.readbyqxmd.com/read/28486405/compensation-of-pvt-variations-in-tof-imagers-with-in-pixel-tdc
#8
Ion Vornicu, Ricardo Carmona-Galán, Ángel Rodríguez-Vázquez
The design of a direct time-of-flight complementary metal-oxide-semiconductor (CMOS) image sensor (dToF-CIS) based on a single-photon avalanche-diode (SPAD) array with an in-pixel time-to-digital converter (TDC) must contemplate system-level aspects that affect its overall performance. This paper provides a detailed analysis of the impact of process parameters, voltage supply, and temperature (PVT) variations on the time bin of the TDC array. Moreover, the design and characterization of a global compensation loop is presented...
May 9, 2017: Sensors
https://www.readbyqxmd.com/read/28485969/atomic-resolution-structural-and-chemical-imaging-revealing-the-sequential-migration-of-ni-co-and-mn-upon-the-battery-cycling-of-layered-cathode
#9
Pengfei Yan, Jianming Zheng, Ji-Guang Zhang, Chongmin Wang
Layered lithium transition metal oxides (LTMO) are promising candidate cathode materials for next-generation high-energy density lithium ion battery. The challenge for using this category of cathode is the capacity and voltage fading, which is believed to be associated with the layered structure disordering, a process that is initiated from the surface or solid-electrolyte interface and facilitated by transition metal (TM) reduction and oxygen vacancy formation. However, the atomic level dynamic mechanism of such a layered structure disordering is still not fully clear...
May 11, 2017: Nano Letters
https://www.readbyqxmd.com/read/28477277/an-efficient-cardiac-mapping-strategy-for-radiofrequency-catheter-ablation-with-active-learning
#10
Yingjing Feng, Ziyan Guo, Ziyang Dong, Xiao-Yun Zhou, Ka-Wai Kwok, Sabine Ernst, Su-Lin Lee
OBJECTIVE: A major challenge in radiofrequency catheter ablation procedures is the voltage and activation mapping of the endocardium, given a limited mapping time. By learning from expert interventional electrophysiologists (operators), while also making use of an active-learning framework, guidance on performing cardiac voltage mapping can be provided to novice operators or even directly to catheter robots. METHODS: A learning from demonstration (LfD) framework, based upon previous cardiac mapping procedures performed by an expert operator, in conjunction with Gaussian process (GP) model-based active learning, was developed to efficiently perform voltage mapping over right ventricles (RV)...
May 5, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28476946/in-vivo-calcium-signaling-during-synaptic-refinement-at-the-drosophila-neuromuscular-junction
#11
Fernando Vonhoff, Haig Keshishian
Neural activity plays a key role in pruning aberrant synapses in various neural systems, including the mammalian cortex, where low frequency (0.01 Hz) calcium oscillations refine topographic maps. However, the activity-dependent molecular mechanisms remain incompletely understood. Activity-dependent pruning also occurs at embryonic Drosophila neuromuscular junctions (NMJs), where low frequency Ca(2+) oscillations are required for synaptic refinement and the response to the muscle-derived chemorepellant Sema2a...
May 5, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28472282/right-ventricular-outflow-tract-high-density-endocardial-unipolar-voltage-mapping-in-patients-with-brugada-syndrome-evidence-for-electroanatomical-abnormalities
#12
Konstantinos P Letsas, Michael Efremidis, Konstantinos Vlachos, Stamatis Georgopoulos, Nikolaos Karamichalakis, Dimitrios Asvestas, Kosmas Valkanas, Panagiotis Korantzopoulos, Tong Liu, Antonios Sideris
Aims: Epicardial structural abnormalities at the right ventricular outflow tract (RVOT) may provide the arrhythmia substrate in Brugada syndrome (BrS). Electroanatomical endocardial unipolar voltage mapping is an emerging tool that accurately identifies epicardial abnormalities in different clinical settings. This study investigated whether endocardial unipolar voltage mapping of the RVOT detects electroanatomical abnormalities in patients with BrS. Methods and results: Ten asymptomatic patients (8 males, 34...
May 2, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28468991/inferring-neuronal-network-functional-connectivity-with-directed-information
#13
Zhiting Cai, Curtis L Neveu, Douglas A Baxter, John H Byrne, Behnaam Aazhang
A major challenge in neuroscience is to develop effective tools that infer the circuit connectivity from large-scale recordings of neuronal activity patterns. In this paper, context tree maximizing (CTM) was used to estimate directed information (DI), which measures causal influences among neural spike trains in order to infer putative synaptic connections. In contrast to existing methods, the method presented here is data-driven and can readily identify both linear and nonlinear relations between neurons. This CTM-DI method reliably identified circuit structures underlying simulations of realistic conductance-based networks...
May 3, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28468392/terahertz-generation-mechanism-in-nano-grating-electrode-photomixers-on-fe-doped-ingaasp
#14
Reshma A Mohandas, Joshua R Freeman, Michele Natrella, Mark C Rosamond, Lalitha Ponnampalam, Martyn J Fice, Alwyn J Seeds, Paul J Cannard, Michael J Robertson, David G Moodie, A Giles Davies, Edmund H Linfield, Paul Dean
We report the generation mechanism associated with nano-grating electrode photomixers fabricated on Fe-doped InGaAsP substrates. Two different emitter designs incorporating nano-gratings coupled to the same broadband antenna were characterized in a continuous-wave terahertz (THz) frequency system employing telecommunications wavelength lasers for generation and coherent detection. The current-voltage characteristics and THz emission bandwidth of the emitters is compared for different bias polarities and optical polarisations...
May 1, 2017: Optics Express
https://www.readbyqxmd.com/read/28446015/realistic-electric-field-mapping-of-anisotropic-muscle-during-electrical-stimulation-using-a-combination-of-water-diffusion-tensor-and-electrical-conductivity
#15
Bup Kyung Choi, Tong In Oh, Saurav Zk Sajib, Jin Woong Kim, Hyung Joong Kim, Oh In Kwon, Eung Je Woo
PURPOSE: To realistically map the electric fields of biological tissues using a diffusion tensor magnetic resonance electrical impedance tomography (DT-MREIT) method to estimate tissue response during electrical stimulation. METHODS: Imaging experiments were performed using chunks of bovine muscle. Two silver wire electrodes were positioned inside the muscle tissue for electrical stimulation. Electric pulses were applied with a 100-V amplitude and 100-μs width using a voltage stimulator...
April 2017: International Neurourology Journal
https://www.readbyqxmd.com/read/28443653/borophane-as-a-benchmate-of-graphene-a-potential-2d-material-for-anode-of-li-and-na-ion-batteries
#16
Naresh K Jena, Rafael B Araujo, Vivekanand Shukla, Rajeev Ahuja
Borophene, single atomic-layer sheet of boron ( Science 2015 , 350 , 1513 ), is a rather new entrant into the burgeoning class of 2D materials. Borophene exhibits anisotropic metallic properties whereas its hydrogenated counterpart borophane is reported to be a gapless Dirac material lying on the same bench with the celebrated graphene. Interestingly, this transition of borophane also rendered stability to it considering the fact that borophene was synthesized under ultrahigh vacuum conditions on a metallic (Ag) substrate...
May 2, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28432503/high-voltage-zones-within-the-pulmonary-vein-antra-major-determinants-of-acute-pulmonary-vein-reconnections-after-atrial-fibrillation-ablation
#17
Koichi Nagashima, Ichiro Watanabe, Yasuo Okumura, Kazuki Iso, Keiko Takahashi, Ryuta Watanabe, Masaru Arai, Sayaka Kurokawa, Toshiko Nakai, Kimie Ohkubo, Shunichi Yoda, Atsushi Hirayama
PURPOSE: Recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) is mainly due to PV reconnections. Patient-specific tissue characteristics that may contribute remain unidentified. This study aimed to assess the relationship between the bipolar electrogram voltage amplitudes recorded from the PV-left atrial (LA) junction and acute PV reconnection sites. METHODS: Three-dimensional LA voltage maps created before an extensive encircling PVI in 47 AF patients (31 men; mean age 62 ± 11 years) were examined for an association between the EGM voltage amplitude recorded from the PV-LA junction and acute post-PVI PV reconnections (spontaneous PV reconnections and/or ATP-provoked dormant PV conduction)...
April 21, 2017: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/28430892/anti-arrhythmic-potential-of-the-late-sodium-current-inhibitor-gs-458967-in-murine-scn5a-1798insd-and-human-scn5a-1795insd-ipsc-derived-cardiomyocytes
#18
Vincent Portero, Simona Casini, Maaike Hoekstra, Arie O Verkerk, Isabella Mengarelli, Luiz Belardinelli, Sridharan Rajamani, Arthur A M Wilde, Connie R Bezzina, Marieke W Veldkamp, Carol Ann Remme
Aims: Selective inhibition of cardiac late sodium current (INaL) is an emerging target in the treatment of ventricular arrhythmias. We investigated the electrophysiological effects of GS-458967 (GS967), a potent, selective inhibitor of INaL, in an overlap syndrome model of both gain and loss of sodium channel function, comprising cardiomyocytes derived from both human SCN5A-1795insD+/- induced pluripotent stem cells (hiPSC-CMs) and mice carrying the homologous mutation Scn5a-1798insD+/-...
June 1, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28430225/phase-shifting-by-wavelength-modulation-in-a-cube-beam-splitter-interferometer
#19
Uriel Rivera-Ortega
A low-cost and fully automated process for phase-shifting interferometry by continuously changing the input voltage of a laser diode under the scheme of a cube beam splitter interferometer, performing as a two-window common-path interferometric setup, is presented. The input signal of a laser diode is controlled by a data acquisition device which permits a change in its wavelength according to its tunability features. The automation and data analysis is done using LabVIEW in combination with MATLAB. By using the Carré algorithm, the phase map is obtained...
April 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28419208/interhemispheric-synchrony-of-spontaneous-cortical-states-at-the-cortical-column-level
#20
Kazunori O'Hashi, Tomer Fekete, Thomas Deneux, Rina Hildesheim, Cees van Leeuwen, Amiram Grinvald
In cat early visual cortex, neural activity patterns resembling evoked orientation maps emerge spontaneously under anesthesia. To test if such patterns are synchronized between hemispheres, we performed bilateral imaging in anesthetized cats using a new improved voltage-sensitive dye. We observed map-like activity patterns spanning early visual cortex in both hemispheres simultaneously. Patterns virtually identical to maps associated with the cardinal and oblique orientations emerged as leading principal components of the spontaneous fluctuations, and the strength of transient orientation states was correlated with their duration, providing evidence that these maps are transiently attracting states...
April 13, 2017: Cerebral Cortex
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