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Electro physiology

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https://www.readbyqxmd.com/read/28183644/facile-preparation-of-poly-methylene-blue-modified-carbon-paste-electrode-for-the-detection-and-quantification-of-catechin
#1
G Manasa, Ronald J Mascarenhas, Ashis K Satpati, Ozma J D'Souza, A Dhason
Free radicals are formed as byproducts of metabolism, and are highly unstable due to the presence of unpaired electrons. They readily react with other important cellular components such as DNA causing them damage. Antioxidants such as (+)-catechin (CAT), neutralize free radicals in the blood stream. Hence there is a need for detection and quantification of catechin concentration in various food sources and beverages. Electro-oxidative properties of catechin were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV)...
April 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28177156/from-maxwell-s-equations-to-the-theory-of-current-source-density-analysis
#2
Sergey L Gratiy, Geir Halnes, Daniel Denman, Michael J Hawrylycz, Christof Koch, Gaute T Einevoll, Costas A Anastassiou
Despite the widespread use of current-source density (CSD) analysis of extracellular potential recordings in the brain, the physical mechanisms responsible for the generation of the signal are still debated. While the extracellular potential is thought to be exclusively generated by the transmembrane currents, recent studies suggest that extracellular diffusive, advective and displacement currents-traditionally neglected-may also contribute considerably towards extracellular potential recordings. Here, we first justify the application of the electro-quasistatic approximation of Maxwell's equations to describe the electromagnetic field of physiological origin...
February 8, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28168870/annotation-of-functional-impact-of-voltage-gated-sodium-channel-mutations
#3
Valérie Hinard, Aurore Britan, Mathieu Schaeffer, Monique Zahn-Zabal, Urs Thomet, Jean-Sébastien Rougier, Amos Bairoch, Hugues Abriel, Pascale Gaudet
Voltage-gated sodium channels are pore-forming transmembrane proteins that selectively allow sodium ions to flow across the plasma membrane according to the electro-chemical gradient thus mediating the rising phase of action potentials in excitable cells and playing key roles in physiological processes such as neurotransmission, skeletal muscle contraction, heart rhythm and pain sensation. Genetic variations in the nine human genes encoding these channels are known to cause a large range of diseases affecting the nervous and cardiac systems...
February 7, 2017: Human Mutation
https://www.readbyqxmd.com/read/28123904/cryoelectrolysis-electrolytic-processes-in-a-frozen-physiological-saline-medium
#4
Franco Lugnani, Matteo Macchioro, Boris Rubinsky
BACKGROUND: Cryoelectrolysis is a new minimally invasive tissue ablation surgical technique that combines the ablation techniques of electrolytic ablation with cryosurgery. The goal of this study is to examine the hypothesis that electrolysis can take place in a frozen aqueous saline solution. METHOD: To examine the hypothesis we performed a cryoelectrolytic ablation protocol in which electrolysis and cryosurgery are delivered simultaneously in a tissue simulant made of physiological saline gel with a pH dye...
2017: PeerJ
https://www.readbyqxmd.com/read/28113228/variability-of-ventricular-repolarization-dispersion-quantified-by-time-warping-the-morphology-of-the-t-waves
#5
Julia Ramirez, Michele Orini, Derek Tucker, Esther Pueyo, Pablo Laguna
: We propose two electrocardiogram (ECG)-derived markers of T-wave morphological variability in the temporal, dw , and amplitude, da , domains. Two additional markers, d(NL)w and d(NL)a , restricted to measure the non-linear information present within dw and da are also proposed. METHODS: We evaluated the accuracy of the proposed markers in capturing T-wave time and amplitude variations in 3 situations: (1) In a simulated set up with presence of additive Laplacian noise, (2) when modifying the spatio-temporal distribution of electrical repolarization with an electro-physiological cardiac model and (3) in ECG records from healthy subjects undergoing a tilt table test...
October 4, 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28113196/an-electrochemistry-study-of-cryoelectrolysis-in-frozen-physiological-saline
#6
Thomas Manuel, Pujita Munnangi, Boris Rubinsky
Cryoelectrolysis is a new minimally invasive tissue ablation surgical technique that combines the processes of electrolysis and solid/liquid phase transformation (freezing). This study investigated this new technique by measuring the pH front propagation and the changes in resistance in a tissue simulant made of physiological saline gel with a pH dye as a function of the sample temperature in the high subzero range above the eutectic. Results demonstrated that effective electrolysis can occur in a high subzero freezing milieu and that the propagation of the pH front is only weakly dependent on temperature...
December 15, 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28086779/the-effect-of-electrical-conductivity-of-myocardium-on-cardiac-pumping-efficacy-a-computational-study
#7
Ana Rahma Yuniarti, Ki Moo Lim
BACKGROUND AND AIMS: The existence of non-excitable cells in the myocardium leads to the increasing conduction non-uniformity and decreasing myocardial electrical conductivity. Slowed myocardial conduction velocity (MCV) believed to enhance the probability of cardiac arryhthmia and alter the cardiac mechanical pumping efficacy, even in sinus rhythm. Though several studies on the correlation between MCV and cardiac electrical instabilities exist, there has been no study concerning correlation or causality between MCV and cardiac mechanical pumping efficacy, due to the limitation in clinical methods to document and evaluate cardiac mechanical responses directly...
January 10, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28064021/nanosecond-pulsed-electric-field-induced-dose-dependent-phosphatidylinositol-4-5-bisphosphate-signaling-and-intracellular-electro-sensitization
#8
Gleb P Tolstykh, Melissa Tarango, Caleb C Roth, Bennett L Ibey
Previously, it was demonstrated that nanometer-sized pores (nanopores) are formed in outer cellular membranes after exposure to nanosecond electric pulses (nsEPs). We reported that plasma membrane nanoporation affects phospholipids of the cell membrane, culminating in cascading phosphoinositide phosphatidylinositol-4,5-bisphosphate (PIP2) intracellular signaling. In the current study, we show that nsEPs initiated electric field (EF) dose-dependent PIP2 hydrolysis and/or depletion from the plasma membrane. This process was confirmed using fluorescent optical probes of PIP2 hydrolysis: PLCδ-PH-EGFP and GFP-C1-PKCγ-C1a...
January 5, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28041584/hemodynamics-of-his-bundle-pacing
#9
REVIEW
Luca Alberti, Paolo Pieragnoli, Giuseppe Ricciardi, Luigi Padeletti
This review will focus on the feasibility of long term His bundle pacing and its effects on left ventricle (LV) hemodynamics. Compared with right ventricular pacing, His bundle pacing results in a more physiological electro-mechanical activation that contributes to preserve LV function. Moreover some studies showed a similar effect to biventricular pacing in patients with heart failure and left bundle branch block. Recent observations indicate that His bundle pacing should be considered as an optimal site to pace right ventricle in patients who are candidates for cardiac resynchronization therapy...
January 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28010062/covalent-modulators-of-the-vacuolar-atpase
#10
Ying-Chu Chen, Keriann M Backus, Maria Merkulova, Christina Yang, Dennis Brown, Benjamin F Cravatt, Chao Zhang
The vacuolar H(+) ATPase (V-ATPase) is a complex multisubunit machine that regulates important cellular processes through controlling acidity of intracellular compartments in eukaryotes. Existing small-molecule modulators of V-ATPase either are restricted to targeting one membranous subunit of V-ATPase or have poorly understood mechanisms of action. Small molecules with novel and defined mechanisms of inhibition are thus needed to functionally characterize V-ATPase and to fully evaluate the therapeutic relevance of V-ATPase in human diseases...
January 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27965026/disentangling-stimulus-plausibility-and-contextual-congruency-electro-physiological-evidence-for-differential-cognitive-dynamics
#11
Moreno I Coco, Susana Araujo, Karl Magnus Petersson
Expectancy mechanisms are routinely used by the cognitive system in stimulus processing and in anticipation of appropriate responses. Electrophysiology research has documented negative shifts of brain activity when expectancies are violated within a local stimulus context (e.g., reading an implausible word in a sentence) or more globally between consecutive stimuli (e.g., a narrative of images with an incongruent end). In this EEG study, we examine the interaction between expectancies operating at the level of stimulus plausibility and at more global level of contextual congruency to provide evidence for, or against, a disassociation of the underlying processing mechanisms...
February 2017: Neuropsychologia
https://www.readbyqxmd.com/read/27918346/electrical-stimulation-for-seizure-induction-and-functional-mapping-in-stereoelectroencephalography
#12
Agnès Trébuchon, Patrick Chauvel
The challenge in epilepsy surgery is to remove the epileptogenic zone without compromising postoperative function. Electrical stimulation (ES) was developed to identify with greater anatomical and physiological precision cortical structures essential to language and motor function. Because the language network is widely distributed in the left (dominant) hemisphere, and often varies among patients, brain mapping should delineate eloquent areas at the individual level. Although ES for language is commonly performed during a presurgical investigation, the procedure remains nonstandardized among centers, and differences between grids and intracerebral depth electrodes (stereoelectroencephalography) should be taken into account when comparing results from different series...
December 2016: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
https://www.readbyqxmd.com/read/27913147/electro-kinetically-driven-peristaltic-transport-of-viscoelastic-physiological-fluids-through-a-finite-length-capillary-mathematical-modeling
#13
Dharmendra Tripathi, Ashu Yadav, O Anwar Bég
Analytical solutions are developed for the electro-kinetic flow of a viscoelastic biological liquid in a finite length cylindrical capillary geometry under peristaltic waves. The Jefferys' non-Newtonian constitutive model is employed to characterize rheological properties of the fluid. The unsteady conservation equations for mass and momentum with electro-kinetic and Darcian porous medium drag force terms are reduced to a system of steady linearized conservation equations in an axisymmetric coordinate system...
January 2017: Mathematical Biosciences
https://www.readbyqxmd.com/read/27883074/adipose-stem-cells-display-higher-regenerative-capacities-and-more-adaptable-electro-kinetic-properties-compared-to-bone-marrow-derived-mesenchymal-stromal-cells
#14
Ahmed El-Badawy, Marwa Amer, Reda Abdelbaset, Sameh N Sherif, Marwan Abo-Elela, Yehya H Ghallab, Hamdy Abdelhamid, Yehea Ismail, Nagwa El-Badri
Adipose stem cells (ASCs) have recently emerged as a more viable source for clinical applications, compared to bone-marrow mesenchymal stromal cells (BM-MSCs) because of their abundance and easy access. In this study we evaluated the regenerative potency of ASCs compared to BM-MSCs. Furthermore, we compared the dielectric and electro-kinetic properties of both types of cells using a novel Dielectrophoresis (DEP) microfluidic platform based on a printed circuit board (PCB) technology. Our data show that ASCs were more effective than BM-MSCs in promoting neovascularization in an animal model of hind-limb ischemia...
November 24, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27881667/a-mechanistic-physicochemical-model-of-carbon-dioxide-transport-in-blood
#15
David Patrick O'Neill, Peter A Robbins
A number of mathematical models have been produced that, given the Pco2 and Po2 of blood, will calculate the total concentrations for CO2 and O2 in blood. However, all these models contain at least some empirical features, and thus do not represent all of the underlying physicochemical processes in an entirely mechanistic manner. The aim of this study was to develop a physicochemical model of CO2 carriage by the blood to determine whether our understanding of the physical chemistry of the major chemical components of blood together with their interactions is sufficiently strong to predict the physiological properties of CO2 carriage by whole blood...
November 23, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27858026/a-portable-microfluidic-system-for-rapid-measurement-of-the-erythrocyte-sedimentation-rate
#16
Ziya Isiksacan, Ozcan Erel, Caglar Elbuken
The erythrocyte sedimentation rate (ESR) is a frequently used 30 min or 60 min clinical test for screening of several inflammatory conditions, infections, trauma, and malignant diseases, as well as non-inflammatory conditions including prostate cancer and stroke. Erythrocyte aggregation (EA) is a physiological process where erythrocytes form face-to-face linear structures, called rouleaux, at stasis or low shear rates. In this work, we proposed a method for ESR measurement from EA. We developed a microfluidic opto-electro-mechanical system, using which we experimentally showed a significant correlation (R(2) = 0...
November 18, 2016: Lab on a Chip
https://www.readbyqxmd.com/read/27783269/anion-channels-of-mitochondria
#17
Devasena Ponnalagu, Harpreet Singh
Mitochondria are the "power house" of a cell continuously generating ATP to ensure its proper functioning. The constant production of ATP via oxidative phosphorylation demands a large electrochemical force that drives protons across the highly selective and low-permeable mitochondrial inner membrane. Besides the conventional role of generating ATP, mitochondria also play an active role in calcium signaling, generation of reactive oxygen species (ROS), stress responses, and regulation of cell-death pathways...
October 26, 2016: Handbook of Experimental Pharmacology
https://www.readbyqxmd.com/read/27762540/electro-photodynamic-visualization-of-singlet-oxygen-induced-by-zinc-porphyrin-modified-microchip-in-aqueous-media
#18
Chuanguang Yao, Hongxin Song, Ying Wan, Kefeng Ma, Chenyu Zheng, Hongda Cui, Peng Xin, Xubo Ji, Shengyuan Deng
A porphyrin-based electro-photodynamic imaging system was fabricated for monitoring the concentration of oxygen. Distinct from the electrochemiluminescent (ECL) inability of numerous organic species in aqueous solutions, a strong and stable red irradiation at 634 nm could be stimulated electrochemically on zinc(II) meso-tetra(4-carboxyphenyl) porphine (ZnTCPP)/tetraoctylammonium bromide (TOAB) in the physiological condition. In terms of in situ electron paramagnetic resonance and ECL spectroscopies, the nature of ECL was thoroughly investigated, being exactly the chemiluminescence from singlet oxygen ((1)O2) produced during the successive electro-reduction of ZnTCPP...
December 21, 2016: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/27664111/electro-physiological-changes-in-the-brain-induced-by-caffeine-or-glucose-nasal-spray
#19
K De Pauw, B Roelands, J Van Cutsem, U Marusic, T Torbeyns, R Meeusen
OBJECTIVE: A direct link between the mouth cavity and the brain for glucose (GLUC) and caffeine (CAF) has been established. The aim of this study is to determine whether a direct link for both substrates also exist between the nasal cavity and the brain. METHODS: Ten healthy male subjects (age 22 ± 1 years) performed three experimental trials, separated by at least 2 days. Each trial included a 20-s nasal spray (NAS) period in which solutions placebo (PLAC), GLUC, or CAF were provided in a double-blind, randomized order...
January 2017: Psychopharmacology
https://www.readbyqxmd.com/read/27642859/the-effect-of-game-design-goal-type-and-player-numbers-on-the-physiological-and-physical-demands-of-hurling-specific-small-sided-games
#20
Shane Malone, Kieran Collins
The current study examined the effect that game design modification, goal type and player numbers on the running performance and physiological demands of small-sided hurling games (SSG). Forty-eight hurling players (age 25.5 ± 3.2 years; height 178.9 ± 3.2 cm; body mass 78.5 ± 4.5 kg) performed four types of SSG (possession (P), normal play (NP), regular Goals (RG) and small goals (SG) in four-a-side, five-a-side and six-a-side formats. Heart rate (Polar Electro Oy, Kempele, Finland) and Global positioning system technology (VX Sport, 4-Hz, Lower Hutt, New Zealand) were used to analyse the physical and physiological differences between SSG...
September 6, 2016: Journal of Strength and Conditioning Research
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