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Waveform duration

Robert D Black, Lesco L Rogers, Kristen K Ade, Heather A Nicoletto, Heather D Adkins, Daniel T Laskowitz
Caloric vestibular stimulation (CVS) to elicit the vestibulo-ocular reflex has long been used in clinical settings to aid in the diagnosis of balance disorders and to confirm the absence of brainstem function. While a number of studies have hinted at the potential therapeutic applications of CVS, the limitations of existing devices have frustrated that potential. Current CVS irrigators use water or air during short-duration applications; however, this approach is not tenable for longer duration therapeutic protocols or home use...
2016: IEEE Journal of Translational Engineering in Health and Medicine
Desmond H Y Tse, Christopher J Wiggins, Benedikt A Poser
PURPOSE: In order to fully benefit from the improved signal-to-noise and contrast-to-noise ratios at 9.4T, the challenges of B1+ inhomogeneity and the long acquisition time of high-resolution 2D gradient-recalled echo (GRE) imaging were addressed. THEORY AND METHODS: Flip angle homogenized excitations were achieved by parallel transmission (pTx) of 3-spoke pulses, designed by magnitude least-squares optimization in a slice-by-slice fashion; the acquisition time reduction was achieved by simultaneous multislice (SMS) pulses...
October 23, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Elena Bartoloni, Giacomo Pucci, Francesca Cannarile, Francesca Battista, Alessia Alunno, Marco Giuliani, Giacomo Cafaro, Roberto Gerli, Giuseppe Schillaci
Although microvascular disease is a hallmark of systemic sclerosis (SSc), a higher prevalence of macrovascular disease and a poorer related prognosis have been reported in SSc than in the general population. The simultaneous assessment of prognostically relevant functional properties of larger and smaller arteries, and their effects on central hemodynamics, has never been performed in SSc using the state-of-the-art techniques. Thirty-four women with SSc (aged 61±15 years, disease duration 17±12 years, and blood pressure 123/70±18/11 mm Hg) and 34 healthy women individually matched by age and mean arterial pressure underwent the determination of carotid-femoral (aortic) and carotid-radial (upper limb) pulse wave velocity (a direct measure of arterial stiffness), aortic augmentation (a measure of the contribution of reflected wave to central pulse pressure), and aortobrachial pulse pressure amplification (brachial/aortic pulse pressure) through applanation tonometry (SphygmoCor)...
October 17, 2016: Hypertension
Koichiro Nakamura, Stefan Jun Groiss, Masashi Hamada, Hiroyuki Enomoto, Suguru Kadowaki, Mitsunari Abe, Takenobu Murakami, Winnugroho Wiratman, Fangyu Chang, Shunsuke Kobayashi, Ritsuko Hanajima, Yasuo Terao, Yoshikazu Ugawa
BACKGROUND: Responses to plasticity-inducing brain stimulation protocols are highly variable. However, no data are available concerning the variability of responses to quadripulse stimulation (QPS). OBJECTIVE: We assessed the QPS parameters of motor cortical plasticity induction in a systematic manner, and later investigated the variability of QPS using optimal parameters. METHODS: First, two different interburst intervals (IBI) with the same total number of pulses were compared...
September 21, 2016: Brain Stimulation
Melda Kunduk, Takeshi Ikuma, David C Blouin, Andrew J McWhorter
OBJECTIVES: This study aimed to investigate the effects of varying volume, pitch, and phonation types on the initiation and termination phases of vocal fold oscillation using high-speed digital videoendoscopy. Specifically, it addressed the effects of the variation of volume, pitch, and phonation type (normal, pressed, and breathy) on the transient duration of the vibrating glottal length (length transient duration, Tlen), the transient duration of the glottal area waveform (area transient duration, Tarea), the time offset between the beginning (or the end) of the full-length vibration and the full-amplitude vibration, TΔ, and the variation of the fundamental frequency during the vocal fold oscillation initiation and termination segments (pitch instability, %PI)...
September 23, 2016: Journal of Voice: Official Journal of the Voice Foundation
Marziye Eshghi, John S Preisser, Mahmood Bijankhan, David J Zajac
PURPOSE: The main objective was to examine temporal parameters of stop-plosives in Persian-speaking children with repaired cleft lip and palate (CLP). METHOD: Eleven children with repaired bilateral CLP and 20 typically-developing children participated in the study. Stop-gap duration (SGD) and voice-onset time (VOT) were measured based on digital waveform and spectrographic displays. RESULT: Separate linear mixed model analyses showed significantly longer SGDs for children with CLP for all plosives in word-mid and final positions...
September 26, 2016: International Journal of Speech-language Pathology
Cliff Reid, Ian Ferguson, Brian Burns, Karel Habig, Mohammed Shareef
BACKGROUND: Life-like end-tidal capnography (ETCO2) waveforms have been demonstrated in recently deceased and fresh-frozen cadavers following tracheal intubation, offering potential for high fidelity airway simulation training. As the mechanism for carbon dioxide production is not fully understood, it is possible that oesophageal intubation may also generate a capnograph. Our aim was to measure ETCO2 levels following (1) oesophageal and (2) tracheal intubation in fresh-frozen cadavers, and to observe the size, shape and duration of any capnographic waveform...
September 23, 2016: Emergency Medicine Journal: EMJ
Matthias Kleinheyer, Daniel L Timms, Geoffrey D Tansley, Frank Nestler, Nicholas A Greatrex, O Howard Frazier, William E Cohn
Unlike the earlier reciprocating volume displacement-type pumps, rotary blood pumps (RBPs) typically operate at a constant rotational speed and produce continuous outflow. When RBP technology is used in constructing a total artificial heart (TAH), the pressure waveform that the TAH produces is flat, without the rise and fall associated with a normal arterial pulse. Several studies have suggested that pulseless circulation may impair microcirculatory perfusion and the autoregulatory response and may contribute to adverse events such as gastrointestinal bleeding, arteriovenous malformations, and pump thrombosis...
September 2016: Artificial Organs
M Staniszewska, A Pudło, K Ryterska, E Stachowska
OBJECTIVE: The progression of cardiovascular disease is blunted by regular exercise training as a common non-pharmacological treatment. Recent findings have confirmed that central aortic pressure is more strongly related to cardiovascular events than brachial blood pressure. The aim of the study was to evaluate the influence of a single bout of significant physical effort on central aortic pressure and pulse wave velocity in young male athletes. PATIENTS AND METHODS: The study group consisted of 16 healthy male athletes undergoing regular endurance training...
August 2016: European Review for Medical and Pharmacological Sciences
Yasunobu Hayabuchi, Akemi Ono, Yukako Homma, Shoji Kagami
BACKGROUND: We hypothesized that longitudinal pulmonary arterial deformation during the cardiac cycle reflects pulmonary arterial capacitance. To examine this hypothesis, we assessed whether tissue Doppler-derived pulmonary annular motion could serve as a novel way to evaluate pulmonary arterial capacitance in pediatric patients with ventricular septal defect (VSD). METHODS: In this prospective study, pulmonary annular velocity was measured in children (age, 6 months-5 years) with a preoperative VSD (VSD group, n = 35) and age-matched healthy children (Control group, n = 23)...
September 7, 2016: Cardiovascular Ultrasound
Mohammed Ashrafi, Teresa Alonso-Rasgado, Mohamed Baguneid, Ardeshir Bayat
Current gold standard lower extremity cutaneous wound management is not always effective. Cutaneous wounds generate a "current of injury" which is directly involved in wound healing processes. Application of exogenous electrical stimulation has been hypothesised to imitate the natural electric current that occurs in cutaneous wounds. The aim of this extensive review is to provide a detailed update on the variety of electrical stimulation modalities used in the management of lower extremity wounds. Several different waveforms and delivery methods of electrical stimulation have been used...
August 30, 2016: Experimental Dermatology
Ljuba Bacharova, Vavrinec Szathmary, Jana Svehlikova, Anton Mateasik, Milan Tysler
Diffuse or regional activation slowing in ventricular myocardium can result from different cardiac pathologies, such as left ventricular hypertrophy, ischemia or fibrosis. Altered ventricular activation sequence leads to deformations of the activation front and consequently to the changes in the QRS complex. Using a computer model we simulated the effect of slowed ventricular activation on the QRS waveform with a special interest in ECG changes which reproduce the ECG criteria of left ventricular hypertrophy (ECG-LVH)...
August 5, 2016: Journal of Electrocardiology
Gerd A Wagner, David F Plusquellic
A ground-based, integrated path, differential absorption light detection and ranging (IPDA LIDAR) system is described and characterized for a series of nighttime studies of CO<sub>2</sub>, CH<sub>4</sub>, and H<sub>2</sub>O. The transmitter is based on an actively stabilized, continuous-wave, single-frequency external-cavity diode laser (ECDL) operating from 1.60 to 1.65 μm. The fixed frequency output of the ECDL is microwave sideband tuned using an electro-optical phase modulator driven by an arbitrary waveform generator and filtered using a confocal cavity to generate a sequence of 123 frequencies separated by 300 MHz...
August 10, 2016: Applied Optics
B Hametner, S Parragh, S Wassertheurer, T Weber
OBJECTIVE: Pulse wave velocity (PWV) predicts cardiovascular events in different patient groups and in the general population. Its value in patients evaluated for suspected coronary artery disease (CAD) has never been clarified. In addition, the particular value of "true" aortic PWV (aoPWV) is unknown. DESIGN AND METHOD: We prospectively measured aoPWV invasively during catheter pullback in patients undergoing diagnostic coronary angiography (aoPWVmeas), and we estimated aoPWV non-invasively from age, systolic blood pressure, and waveform characteristics, using the validated ARCSolver method (aoPWVestim)...
September 2016: Journal of Hypertension
T Weber, S Wassertheurer, B Hametner, S Parragh, S Moebus, N Pundt, A A Mahabadi, U Roggenbuck, N Lehmann, A Stang, K H Jöckel, R Erbel
OBJECTIVE: Pulsatile hemodynamics (central pressures, antegrade and backward waves, aortic stiffness) are independent predictors of major cardiovascular events. Population-based reference values for wave separation analysis (WSA) based parameters (amplitude of forward wave - Pf and backward wave - Pb) in middle-aged and elderly individuals are currently missing. DESIGN AND METHOD: In 2690 participants from the population-based Heinz Nixdorf Recall Study, we performed high-fidelity radial tonometry, calibrated waveforms with brachial blood pressures and processed them with a transfer function to derive central pressures...
September 2016: Journal of Hypertension
Pei Zhou, Fangzheng Zhang, Qingshui Guo, Shilong Pan
A scheme for photonic generation of linearly chirped microwave waveforms (LCMWs) with a large time-bandwidth product (TBWP) is proposed and demonstrated based on an optically injected semiconductor laser. In the proposed system, the optically injected semiconductor laser is operated in period-one (P1) oscillation state. After optical-to-electrical conversion, a microwave signal can be generated with its frequency determined by the injection strength. By properly controlling the injection strength, an LCMW with a large TBWP can be generated...
August 8, 2016: Optics Express
A Ryabov, P Baum
Rapidly changing electromagnetic fields are the basis of almost any photonic or electronic device operation. We report how electron microscopy can measure collective carrier motion and fields with subcycle and subwavelength resolution. A collimated beam of femtosecond electron pulses passes through a metamaterial resonator that is previously excited with a single-cycle electromagnetic pulse. If the probing electrons are shorter in duration than half a field cycle, then time-frozen Lorentz forces distort the images quasi-classically and with subcycle time resolution...
July 22, 2016: Science
Wei Zong, Larry Nielsen, Brian Gross, Juan Brea, Joseph Frassica
There has been a high rate of false alarms for the critical electrocardiogram (ECG) arrhythmia events in intensive care units (ICUs), from which the 'crying-wolf' syndrome may be resulted and patient safety may be jeopardized. This article presents an algorithm to reduce false critical arrhythmia alarms using arterial blood pressure (ABP) and/or photoplethysmogram (PPG) waveform features. We established long duration reference alarm datasets which consist of 573 ICU waveform-alarm records (283 for development set and 290 for test set) with total length of 551 patent days...
August 2016: Physiological Measurement
Joshua Mayourian, Ruben M Savizky, Eric A Sobie, Kevin D Costa
Human mesenchymal stem cell (hMSC) delivery has demonstrated promise in preclinical and clinical trials for myocardial infarction therapy; however, broad acceptance is hindered by limited understanding of hMSC-human cardiomyocyte (hCM) interactions. To better understand the electrophysiological consequences of direct heterocellular connections between hMSCs and hCMs, three original mathematical models were developed, representing an experimentally verified triad of hMSC families with distinct functional ion channel currents...
July 2016: PLoS Computational Biology
S V Tapilina, D V Abramochkin
Type 3 muscarinic receptors (M3 receptors) participate in the mediation of cholinergic effects in mammalian myocardium, along with M2 receptors. However, myocardium of adult mammals demonstrates only modest electrophysiological effects in response to selective stimulation of M3 receptors which are hardly comparable to the effects produced by M2 stimulation. In the present study, the effects of selective M3 stimulation induced by application of the muscarinic agonist pilocarpine (10 μM) in the presence of the selective M2 blocker methoctramine (100 nM) on the action potential (AP) waveform were investigated in isolated atrial and ventricular preparations from newborn and 3-week-old rats and compared to those in preparations from adult rats...
April 2016: Acta Naturae
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