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https://www.readbyqxmd.com/read/29311162/differential-expression-and-remodeling-of-transient-outward-potassium-currents-in-human-left-ventricles
#1
Eric K Johnson, Steven J Springer, Wei Wang, Edward J Dranoff, Yan Zhang, Evelyn M Kanter, Kathryn A Yamada, Jeanne M Nerbonne
BACKGROUND: Myocardial, transient, outward currents, Ito, have been shown to play pivotal roles in action potential (AP) repolarization and remodeling in animal models. The properties and contribution of Ito to left ventricular (LV) repolarization in the human heart, however, are poorly defined. METHODS AND RESULTS: Whole-cell, voltage-clamp recordings, acquired at physiological (35°C to 37°C) temperatures, from myocytes isolated from the LV of nonfailing human hearts identified 2 distinct transient currents, Ito,fast (Ito,f) and Ito,slow (Ito,s), with significantly (P<0...
January 2018: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29309274/temporary-persistence-of-conduction-block-after-prolonged-kilohertz-frequency-alternating-current-on-rat-sciatic-nerve
#2
Narendra Bhadra, Emily Foldes, Tina Vrabec, Kevin Kilgore, Niloy Bhadra
OBJECTIVE: Application of kilohertz frequency alternating current (KHFAC) waveforms can result in nerve conduction block that is induced in less than a second. Conduction recovers within seconds when KHFAC is applied for about 5-10 min. This study investigated the effect of repeated and prolonged application of KHFAC on rat sciatic nerve with bipolar platinum electrodes. APPROACH: Varying durations of KHFAC at signal amplitudes for conduction block with intervals of no stimulus were studied...
January 8, 2018: Journal of Neural Engineering
https://www.readbyqxmd.com/read/29289224/a-high-pressure-metallic-core-holder-for-magnetic-resonance-based-on-hastelloy-c
#3
M Shakerian, F Marica, A Afrough, F G Goora, M Li, S Vashaee, B J Balcom
A metallic core holder, fabricated from non-magnetic Hastelloy-C276, has been designed for Magnetic Resonance (MR) and Magnetic Resonance Imaging (MRI) of core plug samples at high pressures and temperatures. Core plug samples, 1.5″ in diameter and 2″ in length, can be tested in the core holder at elevated pressures and temperatures, up to 5000 psi and 80 °C. These are conditions commonly found in petroleum reservoirs. A radio frequency probe, which excites and detects magnetic resonance signals, was placed inside the metal vessel...
December 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29289210/high-speed-and-low-distortion-solution-for-time-correlated-single-photon-counting-measurements-a-theoretical-analysis
#4
A Cominelli, G Acconcia, P Peronio, M Ghioni, I Rech
In this paper, we describe a novel solution to increase the speed of Time-Correlated Single Photon Counting (TCSPC) measurements by almost an order of magnitude while providing, in principle, zero distortion regardless of the experimental conditions. Typically, the relatively long dead time associated with the conversion electronics requires a proper tune of the excitation power in order to avoid distortions of the reconstructed waveform due to pileup and counting loss. As a result, the maximum operating rate of a TCSPC channel is now limited between 1% and 5% of the excitation frequency, thus leading to relatively long acquisition times...
December 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29288837/does-eye-velocity-due-to-infantile-nystagmus-deprive-visual-acuity-development
#5
John P Kelly, James O Phillips, Avery H Weiss
PURPOSE: To use eye movement recordings of young children to determine whether eye velocity from infantile nystagmus (IN) deprives the developing visual system of normal visual acuity. METHOS: The video-oculography recordings and visual acuity measurements (including Teller cards) of 15 children ≤6.0 years of age with IN without visual sensory disease (idiopathic IN) were reviewed retrospectively. Eye velocity that would limit visual acuity development was predicted from both empirical adult data adjusted for age and a temporal limitation model using published photoreceptor density data with age...
December 27, 2017: Journal of AAPOS: the Official Publication of the American Association for Pediatric Ophthalmology and Strabismus
https://www.readbyqxmd.com/read/29282675/electropenetrography-epg-a-breakthrough-tool-unveiling-stink-bug-pentatomidae-feeding-on-plants
#6
REVIEW
T Lucini, A R Panizzi
In this article, we review and discuss the potential use of EPG (electropenetrography) as a powerful tool to unveil the feeding process of phytophagous stink bugs (pentatomids). These bugs are relatively big and vigorous, which presents a problem during wiring (i.e., attachment of the gold wire on the bug's pronotum) for use in EPG. Once this challenge was overcome, using the sand paper-and-wire technique, several species have been studied using EPG, yielding waveforms that, coupled with histological studies, revealed the ingestion sites on different host plants...
December 27, 2017: Neotropical Entomology
https://www.readbyqxmd.com/read/29279413/association-between-diastolic-blood-pressure-during-pediatric-in-hospital-cardiopulmonary-resuscitation-and-survival
#7
Robert A Berg, Robert M Sutton, Ron W Reeder, John T Berger, Christopher J Newth, Joseph A Carcillo, Patrick S McQuillen, Kathleen L Meert, Andrew R Yates, Rick E Harrison, Frank W Moler, Murray M Pollack, Todd C Carpenter, David L Wessel, Tammara L Jenkins, Daniel A Notterman, Richard Holubkov, Robert F Tamburro, J Michael Dean, Vinay M Nadkarni
Background -Based on laboratory cardiopulmonary resuscitation (CPR) investigations and limited adult data demonstrating that survival depends on attaining adequate arterial diastolic blood pressure (DBP) during CPR, American Heart Association recommends using BP to guide pediatric CPR. However, evidence-based BP targets during pediatric CPR remain an important knowledge gap for CPR guidelines. Methods -All children ≥37 weeks gestation and <19 years old in Collaborative Pediatric Critical Care Research Network intensive care units with chest compressions for ≥1 minute and invasive arterial blood pressure monitoring prior to and during CPR between July 1, 2013 and June 31, 2016 were included...
December 26, 2017: Circulation
https://www.readbyqxmd.com/read/29248744/underbody-blast-effect-on-the-pelvis-and-lumbar-spine-a-computational-study
#8
Jianyin Lei, Feng Zhu, Binhui Jiang, Zhihua Wang
Explosion from an anti-tank landmine under a military vehicle, known as underbody blast (UBB), may cause severe injury or even death for the occupants inside the vehicle. Severity and patterns of lower extremity, pelvis and lumbar spine injuries subjected to UBB have been found highly related to loading conditions, i.e. the vertical acceleration pulse. A computational human model has been developed and successfully simulated the tibia fracture under UBB in the previous study. In the present study, it was further improved by building a detailed lumbar spine and pelvis model with high biofidelity...
December 5, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/29226954/effect-of-carrot-puree-in-vegetable-juice-on-linguapalatal-swallowing-pressure
#9
Hatsue Moritaka, Machiko Mineki, Makoto Kobayashi, Takahiro Ono, Kazuhiro Hori
This study aimed to ascertain the influence of various amounts (0-30%) of carrot puree (CP) in vegetable juice on linguapalatal swallowing pressure in healthy volunteers. Twenty healthy women (age range: 20-22 years) swallowed a 17-mL drink in a natural state, and linguapalatal swallowing pressure was measured using a special sensor sheet. Peak magnitude (maximum pressure of the tongue pushing on the hard palate), integrated values of linguapalatal swallowing pressure on the waveform, and duration of linguapalatal swallowing pressure were increased with increases in CP concentrations...
December 11, 2017: Journal of Texture Studies
https://www.readbyqxmd.com/read/29225574/motor-unit-activity-during-fatiguing-isometric-muscle-contraction-in-hemispheric-stroke-survivors
#10
Lara McManus, Xiaogang Hu, William Z Rymer, Nina L Suresh, Madeleine M Lowery
Enhanced muscle weakness is commonly experienced following stroke and may be accompanied by increased susceptibility to fatigue. To examine the contributions of central and peripheral factors to isometric muscle fatigue in stroke survivors, this study investigates changes in motor unit (MU) mean firing rate, and action potential duration during, and directly following, a sustained submaximal fatiguing contraction at 30% maximum voluntary contraction (MVC). A series of short contractions of the first dorsal interosseous muscle were performed pre- and post-fatigue at 20% MVC, and again following a 10-min recovery period, by 12 chronic stroke survivors...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/29223824/correlating-motor-unit-morphology-with-bioelectrical-activity-a-simulation-study
#11
Ewa Zalewska, Irena Hausmanowa-Petrusewicz
OBJECTIVES: The aim was to determine motor unit morphology underpinning the various MUP waveforms using MUP analysis. METHOD: The simulation method is based on the decomposition of MUP into single fiber potentials. Number of fibers, fiber diameters and fiber to electrode distances were determined. The impact of each muscle fiber on the MUP waveform was determined and quantified by its percentage contribution. RESULTS: The origin of the four examined MUPs of distinct waveforms have been explained by showing the histograms of fiber diameters and their distance to the electrode...
November 16, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29222865/multipoint-pacing-improves-peripheral-hemodynamic-response-non-invasive-assessment-using-radial-artery-tonometry
#12
Giuseppe Ciconte, Žarko Ćalović, Gabriele Vicedomini, Amarild Cuko, Luke C McSpadden, Chunlan Jiang, Kyungmoo Ryu, Igor Caporaso, Robert Stutz, Dean Winter, Massimo Saviano, Raffaele Vitale, Manuel Conti, Vincenzo Santinelli, Carlo Pappone
BACKGOUND: Multipoint left ventricular (LV) pacing (MultiPoint™ Pacing [MPP], Abbott) improves the response rate to cardiac resynchronization therapy (CRT). We evaluated the feasibility of non-invasive radial artery tonometry (RAT) to characterize arterial pressure morphology changes (pre-ejection period [PEP] and ejection duration [ED]) between conventional CRT and MPP pacing interventions. METHODS: Patients with a MPP-enabled CRT device (Quadra Assura MP™, Abbott) underwent non-invasive RAT assessment (SphygmoCor CVMS, AtCor Medical Inc...
December 9, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/29184336/speech-signal-analysis-and-pattern-recognition-in-diagnosis-of-dysarthria
#13
Minu George Thoppil, C Santhosh Kumar, Anand Kumar, John Amose
Background: Dysarthria refers to a group of disorders resulting from disturbances in muscular control over the speech mechanism due to damage of central or peripheral nervous system. There is wide subjective variability in assessment of dysarthria between different clinicians. In our study, we tried to identify a pattern among types of dysarthria by acoustic analysis and to prevent intersubject variability. Objectives: (1) Pattern recognition among types of dysarthria with software tool and to compare with normal subjects...
October 2017: Annals of Indian Academy of Neurology
https://www.readbyqxmd.com/read/29181609/a-new-class-iii-antiarrhythmic-drug-niferidil-prolongs-action-potentials-in-guinea-pig-atrial-myocardium-via-inhibition-of-rapid-delayed-rectifier
#14
Denis V Abramochkin, Vladislav S Kuzmin, Leonid V Rosenshtraukh
PURPOSE: A new class III antiarrhythmic drug niferidil (RG-2) has been introduced as a highly effective therapy for cases of persistent atrial fibrillation, but ionic mechanisms of its action are poorly understood. In the present study, the effects of niferidil on action potential (AP) waveform and potassium currents responsible for AP repolarization were investigated in guinea pig atrial myocardium. METHODS: APs were recorded with sharp glass microelectrodes in multicellular atrial preparations...
November 27, 2017: Cardiovascular Drugs and Therapy
https://www.readbyqxmd.com/read/29165377/a-novel-3d-pedestrian-navigation-method-for-a-multiple-sensors-based-foot-mounted-inertial-system
#15
Wei Yang, Chundi Xiu, Jianmin Zhang, Dongkai Yang
In this paper, we present a novel method for 3D pedestrian navigation of foot-mounted inertial systems by integrating a MEMS-IMU, barometer, and permanent magnet. Zero-velocity update (ZUPT) is a well-known algorithm to eliminate the accumulated error of foot-mounted inertial systems. However, the ZUPT stance phase detector using acceleration and angular rate is threshold-based, which may cause incorrect stance phase estimation in the running gait pattern. A permanent magnet-based ZUPT detector is introduced to solve this problem...
November 22, 2017: Sensors
https://www.readbyqxmd.com/read/29163220/evaluation-of-optogenetic-electrophysiology-tools-in-human-stem-cell-derived-cardiomyocytes
#16
Susann Björk, Elina A Ojala, Tommy Nordström, Antti Ahola, Mikko Liljeström, Jari Hyttinen, Esko Kankuri, Eero Mervaala
Current cardiac drug safety assessments focus on hERG channel block and QT prolongation for evaluating arrhythmic risks, whereas the optogenetic approach focuses on the action potential (AP) waveform generated by a monolayer of human cardiomyocytes beating synchronously, thus assessing the contribution of several ion channels on the overall drug effect. This novel tool provides arrhythmogenic sensitizing by light-induced pacing in combination with non-invasive, all-optical measurements of cardiomyocyte APs and will improve assessment of drug-induced electrophysiological aberrancies...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29148155/identifying-biomechanical-gait-parameters-in-adolescent-boys-with-haemophilia-using-principal-component-analysis
#17
L B Suckling, D Stephensen, M C Cramp, R Mahaffey, W I Drechsler
INTRODUCTION: Improvements in the medical management for those with haemophilia have resulted in improved clinical outcomes. However, current treatment regimens do not alleviate all joint haemarthroses with the potential for long-term joint deterioration remaining. The evaluation of functional activities such as gait, using standardized tools to monitor children with haemophilia is emerging. AIM: This study explored differences in sagittal plane biomechanics of walking in adolescent boys aged 11-18 years with haemophilia and an age-matched group of typically developing boys...
November 17, 2017: Haemophilia: the Official Journal of the World Federation of Hemophilia
https://www.readbyqxmd.com/read/29142324/an-algorithm-for-the-beat-to-beat-assessment-of-cardiac-mechanics-during-sleep-on-earth-and-in-microgravity-from-the-seismocardiogram
#18
Marco Di Rienzo, Emanuele Vaini, Prospero Lombardi
Seismocardiogram, SCG, is the measure of precordial vibrations produced by the beating heart, from which cardiac mechanics may be explored on a beat-to-beat basis. We recently collected a large amount of SCG data (>69 recording hours) from an astronaut to investigate cardiac mechanics during sleep aboard the International Space Station and on Earth. SCG sleep recordings are characterized by a prolonged duration and wide heart rate swings, thus a specific algorithm was developed for their analysis. In this article we describe the new algorithm and its performance...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29133229/use-of-electrical-penetration-graphs-epg-and-quantitative-pcr-to-evaluate-the-relationship-between-feeding-behaviour-and-pandora-neoaphidis-infection-levels-in-green-peach-aphid-myzus-persicae
#19
Chun Chen, Sudan Ye, Huajun Hu, Chengmei Xue, Xiaoping Yu
A real-time qPCR method was developed, validated, and used to quantity the fungal pathogen, P. neoaphidis, within aphids at different times during infection; colonization rate fitted the Gompertz model well (R(b)=0.9356). Feeding behaviour of P. neoaphidis-infected and uninfected M. persicae were investigated, for the first time, using DC-electrical penetration graphs (DC-EPG) that characterized the waveforms made during different aphid stylet probing periods corresponding to epidermis penetration, salivation and ingestion...
November 10, 2017: Journal of Insect Physiology
https://www.readbyqxmd.com/read/29122445/a-method-for-the-topographical-identification-and-quantification-of-high-frequency-oscillations-in-intracranial-electroencephalography-recordings
#20
Zachary J Waldman, Shoichi Shimamoto, Inkyung Song, Iren Orosz, Anatol Bragin, Itzhak Fried, Jerome Engel, Richard Staba, Michael R Sperling, Shennan A Weiss
OBJECTIVE: To develop a reliable software method using a topographic analysis of time-frequency plots to distinguish ripple (80-200 Hz) oscillations that are often associated with EEG sharp waves or spikes (RonS) from sinusoid-like waveforms that appear as ripples but correspond with digital filtering of sharp transients contained in the wide bandwidth EEG. METHODS: A custom algorithm distinguished true from false ripples in one second intracranial EEG (iEEG) recordings using wavelet convolution, identifying contours of isopower, and categorizing these contours into sets of open or closed loop groups...
October 21, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
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