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https://www.readbyqxmd.com/read/28377112/the-assessment-of-electrophysiological-activity-in-human-induced-pluripotent-stem-cell-derived-cardiomyocytes-exposed-to-dimethyl-sulfoxide-and-ethanol-by-manual-patch-clamp-and-multi-electrode-array-system
#1
Soo-Wang Hyun, Bo-Ram Kim, Sung-Ae Hyun, Joung-Wook Seo
INTRODUCTION: Recently, electrophysiological activity has been effectively measured in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to predict drug-induced arrhythmia. Dimethyl sulfoxide (DMSO) and ethanol have been used as diluting agents in many experiments. However, the maximum DMSO and ethanol concentrations that can be effectively used in the measurement of electrophysiological parameters in hiPSC-CMs-based patch clamp and multi-electrode array (MEA) have not been fully elucidated...
April 1, 2017: Journal of Pharmacological and Toxicological Methods
https://www.readbyqxmd.com/read/28374072/outcomes-following-cryoballoon-ablation-for-atrial-fibrillation-guided-by-pressure-waveform-monitoring-without-the-routine-use-of-pulmonary-venography
#2
Akshit Sharma, Jashdeep Dhoot, Jingyan Wang, Philip Jones, Sanjaya Gupta, Alan P Wimmer
PURPOSE: Pressure waveform analysis has the potential for facilitated assessment of pulmonary vein occlusion during cryoballoon ablation for atrial fibrillation. Data on clinical outcomes using this method are lacking. We sought to validate through clinical outcomes the use of pressure waveform analysis as the primary method of determining pulmonary vein occlusion during cryoballoon ablation. METHODS: A study was performed of 122 consecutive patients with atrial fibrillation (85% paroxysmal) undergoing cryoballoon ablation from May 2014 through July 2015 at a single institution using pressure waveform analysis as the primary method of assessing pulmonary vein occlusion...
April 4, 2017: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/28363820/ventricular-fibrillation-waveform-characteristics-of-the-surface-ecg-impact-of-the-left-ventricular-diameter-and-mass
#3
Judith L Bonnes, Jos Thannhauser, Joris Nas, Sjoerd W Westra, Rutger M G Jansen, Gjerrit Meinsma, Menko-Jan de Boer, Joep L R M Smeets, Wessel Keuper, Marc A Brouwer
BACKGROUND: Despite a promising association between VF waveform characteristics and prognosis after resuscitation, studies with VF-guided treatment have so far not improved outcomes. While driven by the idea that the VF waveform reflects arrest duration, increasing evidence suggests that pre-existent disease-related changes of the myocardium affect ECG-characteristics of VF as well. In this context, we studied the impact of the left ventricular (LV) diameter and mass. METHODS: Cohort of 193 ICD-patients with defibrillation testing at the Radboudumc (2010-2014)...
March 29, 2017: Resuscitation
https://www.readbyqxmd.com/read/28343181/a-non-invasive-method-to-rule-out-transient-tachypnea-of-the-newborn-ttn-fetal-pulmonary-artery-acceleration-to-ejection-time-ratio
#4
Barış Büke, Hatice Akkaya
OBJECTIVE: To investigate whether fetal pulmonary artery acceleration to ejection time (PATET) ratio can predict or rule out subsequent diagnosis of transient tachypnea of the newborn (TTN). METHODS: This prospective cohort study included 105 pregnant women in labor, who met the inclusion criteria. Eighteen of these women were removed from the study cohort, because of an inability to acquire sufficient Doppler waveforms and a longer duration of deliveries. According to subsequent diagnosis of TTN in the neonate, the two groups were constituted, TTN+ and TTN-...
March 27, 2017: Journal of Perinatal Medicine
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
#5
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)...
March 16, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28328507/kilohertz-electrical-stimulation-nerve-conduction-block-effects-of-electrode-surface-area
#6
Yogi A Patel, Brian S Kim, William S Rountree, Robert J Butera
Kilohertz electrical stimulation (KES) induces repeatable and reversible conduction block of nerve activity and is a potential therapeutic option for various diseases and disorders resulting from pathological or undesired neurological activity. However successful translation of KES nerve block to clinical applications is stymied by many unknowns such as the relevance of the onset response, acceptable levels of waveform contamination, and optimal electrode characteristics. We investigated the role of electrode geometric surface area on the KES nerve block threshold using 20 and 40 kHz current-controlled sinusoidal KES...
March 17, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28325557/effects-of-new-antiarrhythmic-agent-ss-68-on-excitation-conduction-electrical-activity-in-purkinje-fibers-and-pulmonary-veins-assessment-of-safety-and-side-effects-risk
#7
Saida K Bogus, Vladislav S Kuzmin, Denis V Abramochkin, Konstantin F Suzdalev, Pavel A Galenko-Yaroshevsky
The compound SS-68 has been selected among numerous new derivatives of indole and demonstrated antiarrhythmic effects in animal models. The present study concerns several aspects of SS-68 safety and efficacy as a potential antiarrhythmic drug. The first estimation of atrioventricular conduction in mammalian heart under SS-68 has been carried out; effects of SS-68 in Purkinje fibers and myocardium of pulmonary veins have been investigated. The drug weakly affects cardiac atrioventricular conduction: only high concentrations of SS-68 (≥10 μmol/L) significantly decrease this parameter...
March 2, 2017: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/28321411/different-densities-of-na-ca-exchange-current-in-t-tubular-and-surface-membranes-and-their-impact-on-cellular-activity-in-a-model-of-rat-ventricular-cardiomyocyte
#8
M Pásek, J Šimurda, G Christé
The ratio of densities of Na-Ca exchanger current (INaCa) in the t-tubular and surface membranes (INaCa-ratio) computed from the values of INaCa and membrane capacitances (Cm) measured in adult rat ventricular cardiomyocytes before and after detubulation ranges between 1.7 and 25 (potentially even 40). Variations of action potential waveform and of calcium turnover within this span of the INaCa-ratio were simulated employing previously developed model of rat ventricular cell incorporating separate description of ion transport systems in the t-tubular and surface membranes...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28320451/personal-medical-electronic-devices-and-walk-through-metal-detector-security-systems-assessing-electromagnetic-interference-effects
#9
Joshua Guag, Bisrat Addissie, Donald Witters
BACKGROUND: There have been concerns that Electromagnetic security systems such as walk-through metal detectors (WTMDs) can potentially cause electromagnetic interference (EMI) in certain active medical devices including implantable cardiac pacemakers and implantable neurostimulators. Incidents of EMI between WTMDs and active medical devices also known as personal medical electronic devices (PMED) continue to be reported. This paper reports on emission measurements of sample WTMDs and testing of 20 PMEDs in a WTMD simulation system...
March 20, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28289377/loss-of-saltation-and-presynaptic-action-potential-failure-in-demyelinated-axons
#10
Mustafa S Hamada, Marko A Popovic, Maarten H P Kole
In cortical pyramidal neurons the presynaptic terminals controlling transmitter release are located along unmyelinated axon collaterals, far from the original action potential (AP) initiation site, the axon initial segment (AIS). Once initiated, APs will need to reliably propagate over long distances and regions of geometrical inhomogeneity like branch points (BPs) to rapidly depolarize the presynaptic terminals and confer temporally precise synaptic transmission. While axon pathologies such as demyelinating diseases are well established to impede the fidelity of AP propagation along internodes, to which extent myelin loss affects propagation along BPs and axon collaterals is not well understood...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28286636/a-comparison-of-commercially-available-auditory-brainstem-response-stimuli-at-a-neurodiagnostic-intensity-level
#11
Devan A Keesling, Jordan Paige Parker, Jason Tait Sanchez
iChirp-evoked auditory brainstem responses (ABRs) yield a larger wave V amplitude at low intensity levels than traditional broadband click stimuli, providing a reliable estimation of hearing sensitivity. However, advantages of iChirp stimulation at high intensity levels are unknown. We tested to see if high-intensity (i.e., 85 dBnHL) iChirp stimulation results in larger and more reliable ABR waveforms than click. Using the commercially available Intelligent Hearing System SmartEP platform, we recorded ABRs from 43 normal hearing young adults...
February 1, 2017: Audiology Research
https://www.readbyqxmd.com/read/28282114/methodology-and-characterization-of-isolation-and-preconcentration-in-a-gas-filled-digital-linear-ion-guide
#12
Zachary P Gotlib, Gregory F Brabeck, Peter T A Reilly
Digital operation of linear ion guides allows them to operate as traps and mass filters by modulating the duty cycles of the two driving waveforms. A gas-filled (5 mTorr) digitally driven quadrupole ion guide was used to demonstrate ion isolation and preconcentration. These abilities allow ion trapping mass spectrometers to be filled to capacity with only ions in the range of interest at essentially any value of m/z. Due to the unique performance characteristics of digitally operated quadrupoles, isolation with purely duty cycle enhanced waveforms was developed with three increasingly sophisticated isolation methods...
March 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28278248/sclerenchymatous-ring-as-a-barrier-to-phloem-feeding-by-asian-citrus-psyllid-evidence-from-electrical-penetration-graph-and-visualization-of-stylet-pathways
#13
Justin George, El-Desouky Ammar, David G Hall, Stephen L Lapointe
Asian citrus psyllid (Diaphorina citri) feeding behaviors play a significant role in the transmission of the phloem-limited Candidatus Liberibacter asiaticus (CLas) bacterium that causes the economically devastating citrus greening disease. Sustained phloem ingestion by D. citri on CLas infected plants is required for pathogen acquisition and transmission. Recent studies have shown a fibrous ring of thick-walled sclerenchyma around the phloem in mature, fully expanded citrus leaves that is more prominent on the abaxial compared with the adaxial side...
2017: PloS One
https://www.readbyqxmd.com/read/28268783/portable-forced-oscillation-device-for-point-of-care-pulmonary-function-testing
#14
Jian Cao, Ashutosh Sabharwal
The forced oscillation technique (FOT) provides a simple and accurate approach for pulmonary function testing. However, most current devices are large and high cost, hence the test remains sparingly used. To address this problem, we verified the feasibility of a smart and portable forced oscillation device based on a small subwoofer and ultrasonic sensor that is targeted at point-of-care pulmonary function testing. In this paper, we first develop and optimize the signal processing algorithm for impedance estimation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268466/an-initial-investigation-into-the-real-time-conversion-of-facial-surface-emg-signals-to-audible-speech
#15
Lorenz Diener, Christian Herff, Matthias Janke, Tanja Schultz
This paper presents early-stage results of our investigations into the direct conversion of facial surface electromyographic (EMG) signals into audible speech in a real-time setting, enabling novel avenues for research and system improvement through real-time feedback. The system uses a pipeline approach to enable online acquisition of EMG data, extraction of EMG features, mapping of EMG features to audio features, synthesis of audio waveforms from audio features and output of the audio waveforms via speakers or headphones...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28257761/membrane-potential-determines-calcium-alternans-through-modulation-of-sr-ca-2-load-and-l-type-ca-2-current
#16
Giedrius Kanaporis, Lothar A Blatter
Alternans is a risk factor for cardiac arrhythmia, including atrial fibrillation. At the cellular level alternans is observed as beat-to-beat alternations in contraction, action potential (AP) morphology and magnitude of the Ca(2+) transient (CaT). It is widely accepted that the bi-directional interplay between membrane voltage and Ca(2+) is crucial for the development of alternans, however recently the attention has shifted to instabilities in cellular Ca(2+) handling, while the role of AP alternation remains poorly understood...
April 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/28253671/autocorrelation-factors-and-intelligibility-of-japanese-monosyllables-in-individuals-with-sensorineural-hearing-loss
#17
Ryota Shimokura, Sakie Akasaka, Tadashi Nishimura, Hiroshi Hosoi, Toshie Matsui
Some Japanese monosyllables contain consonants that are not easily discernible for individuals with sensorineural hearing loss. However, the acoustic features that make these monosyllables difficult to discern have not been clearly identified. Here, this study used the autocorrelation function (ACF), which can capture temporal features of signals, to clarify the factors influencing speech intelligibility. For each monosyllable, five factors extracted from the ACF [Φ(0): total energy; τ1 and ϕ1: delay time and amplitude of the maximum peak; τe: effective duration; Wϕ(0): spectral centroid], voice onset time, speech intelligibility index, and loudness level were compared with the percentage of correctly perceived articulations (144 ears) obtained by 50 Japanese vowel and consonant-vowel monosyllables produced by one female speaker...
February 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28252450/an-analysis-of-beam-parameters-on-proton-acoustic-waves-through-an-analytic-approach
#18
Esra Aytac Kipergil, Hakan Erkol, Serhat Kaya, Gultekin Gulsen, Mehmet Unlu
It has been reported that acoustic waves are generated when a high energy pulsed proton beam is deposited in a small volume within tissue. One possible application of the proton induced acoustics is to get a real-time feedback for intratreatment adjustments by monitoring such acoustic waves. High spatial resolution in ultrasound imaging may reduce proton range uncertainty. Thus, it is crucial to understand the dependence of the acoustic waves on the proton beam characteristics. In this manuscript, firstly, an analytic solution to the proton induced acoustic wave is presented to reveal the dependence of signal on beam parameters, and then combined with an analytic approximation of the Bragg curve...
March 2, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28231486/coded-excitation-waveform-engineering-for-high-frame-rate-synthetic-aperture-ultrasound-imaging
#19
Bahman Lashkari, Kaicheng Zhang, Edem Dovlo, Andreas Mandelis
Coded excitation was initially introduced to ultrasound imaging as a method for enhancing the signal-to-noise ratio (SNR). However, this method was also shown to be helpful in conjunction with synthetic aperture transmission for high frame rate imaging. Recently, we introduced two families of mismatched coded excitations based on frequency modulation chirp and combined frequency modulation and Golay code. Here "mismatched" indicates that the coded excitations generate very small cross-correlations among themselves while each has a very strong autocorrelation...
May 2017: Ultrasonics
https://www.readbyqxmd.com/read/28229302/tremor-analysis-separates-parkinson-s-disease-and-dopamine-receptor-blockers-induced-parkinsonism
#20
Aasef G Shaikh
Parkinson's disease, the most common cause of parkinsonism is often difficult to distinguish from its second most common etiology due to exposure to dopamine receptor blocking agents such as antiemetics and neuroleptics. Dual axis accelerometry was used to quantify tremor in 158 patients with parkinsonism; 62 had Parkinson's disease and 96 were clinically diagnosed with dopamine receptor blocking agent-induced parkinsonism. Tremor was measured while subjects rested arms (resting tremor), outstretched arms in front (postural tremor), and reached a target (kinetic tremor)...
February 22, 2017: Neurological Sciences
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