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Electric current spread

Sanja Brolih, Scott K Parks, Valérie Vial, Jérôme Durivault, Livio Mostosi, Jacques Pouysségur, Gilles Pagès, Vincent Picco
BACKGROUND: In mammals, the AKT/PKB protein kinase family comprises three members (AKT1-3). PI3-Kinase (PI3K), a key oncogene involved in a wide variety of cancers, drives AKT activity. Constitutive activation of the PI3K/AKT pathway has been associated with tumorigenic properties including uncontrolled cell proliferation and survival, angiogenesis, promotion of cellular motility, invasiveness and metastasis. However, AKT1 activity has also been recently shown to repress the invasive properties of breast cancer cells in specific contexts...
March 5, 2018: BMC Cancer
Timothy B Esler, Robert R Kerr, Bahman Tahayori, David B Grayden, Hamish Meffin, Anthony N Burkitt
Currently, a challenge in electrical stimulation of the retina with a visual prosthesis (bionic eye) is to excite only the cells lying directly under the electrode in the ganglion cell layer, while avoiding excitation of axon bundles that pass over the surface of the retina in the nerve fiber layer. Stimulation of overlying axons results in irregular visual percepts, limiting perceptual efficacy. This research explores how differences in fiber orientation between the nerve fiber layer and ganglion cell layer leads to differences in the electrical activation of the axon initial segment and axons of passage...
2018: PloS One
Olga Cozzolino, Maria Marchese, Francesco Trovato, Enrico Pracucci, Gian Michele Ratto, Maria Gabriella Buzzi, Federico Sicca, Filippo M Santorelli
Spreading depression (SD) is a neurophysiological phenomenon characterized by abrupt changes in intracellular ion gradients and sustained depolarization of neurons. It leads to loss of electrical activity, changes in the synaptic architecture, and an altered vascular response. Although SD is often described as a unique phenomenon with homogeneous characteristics, it may be strongly affected by the particular triggering event and by genetic background. Furthermore, SD may contribute differently to the pathogenesis of widely heterogeneous clinical conditions...
2018: Frontiers in Neurology
E B Montufar, M Casas-Luna, M Horynová, S Tkachenko, Z Fohlerová, S Diaz-de-la-Torre, K Dvorak, L Celko, J Kaiser
In this work alpha tricalcium phosphate (α-TCP)/ iron (Fe) composites were developed as a new family of biodegradable, load-bearing and cytocompatible materials. The composites with composition from pure ceramic to pure metallic samples were consolidated by pulsed electric current assisted sintering to minimise processing time and temperature while improving their mechanical performance. The mechanical strength of the composites was increased and controlled with the Fe content, passing from brittle to ductile failure...
February 9, 2018: Acta Biomaterialia
Ilias Pagkalos, Michelle Rogers, Martyn Gordon Boutelle, Emmanuel Mic Drakakis
This paper presents the first application specific integrated chip (ASIC) for the monitoring of patients who have suffered a Traumatic Brain Injury (TBI). By monitoring the neuralphysiological (ECoG) and neurochemical (glucose, lactate and potassium) signals of the injured human brain tissue, it is possible to detect spreading depolarisations, which have been shown to be associated with poor TBI patient outcome. This paper describes the testing of a new 7.5mm2 ASIC fabricated in the commercially available AMS 0...
January 31, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Petro M Lytvyn, Andrian V Kuchuk, Yuriy I Mazur, Chen Li, Morgan E Ware, Zhiming Wang, Vasyl Kladko, Aleksander Belyaev, Gregory J Salamo
We experimentally demonstrate that the conductivity of graded AlxGa1-xN increases as a function of the magnitude of the Al concentration gradient (%Al/nm) due to polarization doping effects, without the use of impurity dopants. By using three up/down graded AlxGa1-xN nanolayers with Al gradients ranging from ~ 0.16 to ~ 0.28 %Al/nm combined in one structure, the effects of polarization engineering for localized electric fields and current transport were investigated. Cross-sectional Kelvin probe force microscopy (KPFM) and conductive atomic force microscopy (C-AFM) was used to directly probe the electrical properties of the films with spatial resolution along the thickness of the growth...
January 30, 2018: ACS Applied Materials & Interfaces
Quoc Vo, Haibin Su, Tuan Tran
Droplet spreading on substrates by electrowetting exhibits either of the two transient behaviours: one characterised by contact line oscillation, and the other one by slow spreading dynamics. The transition between these behaviours remains elusive due to the current limited understanding of the spreading dynamics on the hydrodynamical and electrical properties of electrowetting systems. To understand this transition we propose a model capturing the transition's occurrence based on both the hydrodynamical and electrical parameters...
January 16, 2018: Scientific Reports
Qian-Jie Fu, John J Galvin, Xiaosong Wang
Differences in current spread and/or spread of excitation may differently affect integration of acoustic and electric hearing within (electric-acoustic stimulation, or EAS) or across ears (bimodal). In this study, vowel recognition was measured in normal-hearing subjects listening to simulations of cochlear implant (CI), EAS, and bimodal listening. Residual acoustic hearing was limited between 0.1 and 0.6 kHz. The carrier bandwidth in the CI simulations was varied across carriers: broad-band noise, narrow-band noise, and sine waves...
December 2017: Journal of the Acoustical Society of America
Ewan D Fowler, Cherrie H Kong, Jules Hancox, Mark B Cannell
Rationale: The development of a refractory period for Ca2+ spark initiation after Ca2+ release in cardiac myocytes, should inhibit further Ca2+ release during the action potential (AP) plateau. However, Ca2+ release sites that did not initially activate, or which have prematurely recovered from refractoriness might release Ca2+ later during the AP and alter the cell-wide Ca2+ transient. Objective: To investigate the possibility of late Ca2+ spark (LCS) activity in intact isolated cardiac myocytes using fast confocal line scanning with improved confocality and signal to noise...
December 27, 2017: Circulation Research
Jean Isnard, Delphine Taussig, Fabrice Bartolomei, Pierre Bourdillon, Hélène Catenoix, Francine Chassoux, Mathilde Chipaux, Stéphane Clémenceau, Sophie Colnat-Coulbois, Marie Denuelle, Stéphane Derrey, Bertrand Devaux, Georg Dorfmüller, Vianney Gilard, Marc Guenot, Anne-Sophie Job-Chapron, Elisabeth Landré, Axel Lebas, Louis Maillard, Aileen McGonigal, Lorella Minotti, Alexandra Montavont, Vincent Navarro, Anca Nica, Nicolas Reyns, Julia Scholly, Jean-Christophe Sol, William Szurhaj, Agnès Trebuchon, Louise Tyvaert, Maria Paola Valenti-Hirsch, Luc Valton, Jean-Pierre Vignal, Paul Sauleau
Stereoelectroencephalography (SEEG) was designed and developed in the 1960s in France by J. Talairach and J. Bancaud. It is an invasive method of exploration for drug-resistant focal epilepsies, offering the advantage of a tridimensional and temporally precise study of the epileptic discharge. It allows anatomo-electrical correlations and tailored surgeries. Whereas this method has been used for decades by experts in a limited number of European centers, the last ten years have seen increasing worldwide spread of its use...
December 22, 2017: Neurophysiologie Clinique, Clinical Neurophysiology
Linjing Xu, Alison E Seline, Braden Leigh, Mark Ramirez, C Allan Guymon, Marlan R Hansen
HYPOTHESIS: Microtopographical patterns generated by photopolymerization of methacrylate polymer systems will direct growth of neurites from adult neurons, including spiral ganglion neurons (SGNs). BACKGROUND: Cochlear implants (CIs) provide hearing perception to patients with severe to profound hearing loss. However, their ability to encode complex auditory stimuli is limited due, in part, to poor spatial resolution caused by spread of the electrical currents in the inner ear...
January 2018: Otology & Neurotology
Francesca Eroli, Inge C M Loonen, Arn M J M van den Maagdenberg, Else A Tolner, Andrea Nistri
Endocannabinoids are suggested to control pain, even though their clinical use is not fully validated and the underlying mechanisms are incompletely understood. To clarify the targets of endocannabinoid actions, we studied how activation of the endocannabinoid CB1 receptor (CB1R) affects neuronal responses in two in vitro preparations of rodents, namely the trigeminal sensory ganglion (TG) in culture and a coronal slice of the cerebral cortex. On TG small-medium size neurons, we tested whether submicromolar concentrations of the endogenous CB1R agonist anandamide (AEA) modulated inhibitory GABAA receptors and excitatory ATP-gated P2X3 receptors...
March 15, 2018: Neuropharmacology
T A K Nguyen, Samuel Cavuscens, Maurizio Ranieri, Konrad Schwarz, Nils Guinand, Raymond van de Berg, Thomas van den Boogert, Floor Lucieer, Marc van Hoof, Jean-Philippe Guyot, Herman Kingma, Silvestro Micera, Angelica Perez Fornos
The peripheral vestibular system is critical for the execution of activities of daily life as it provides movement and orientation information to motor and sensory systems. Patients with bilateral vestibular hypofunction experience a significant decrease in quality of life and have currently no viable treatment option. Vestibular implants could eventually restore vestibular function. Most vestibular implant prototypes to date are modified cochlear implants to fast-track development. These use various objective measurements, such as the electrically evoked compound action potential (eCAP), to supplement behavioral information...
2017: Frontiers in Neuroscience
Adam Kapela, Erik J Behringer, Steven S Segal, Nikolaos M Tsoukias
OBJECTIVE: Electrical signaling along the endothelium underlies spreading vasodilation and blood flow control. We use mathematical modeling to determine the electrical properties of the endothelium and gain insight into the biophysical determinants of electrical conduction. METHODS: Electrical conduction data along endothelial cell (EC) tubes (40 μm wide, 2.5 mm long) isolated from mouse skeletal muscle resistance arteries were analyzed using cable equations and a multicellular computational model...
November 8, 2017: Microcirculation: the Official Journal of the Microcirculatory Society, Inc
Jiankang He, Xiang Zhao, Jinke Chang, Dichen Li
Cell printing has gained extensive attentions for the controlled fabrication of living cellular constructs in vitro. Various cell printing techniques are now being explored and developed for improved cell viability and printing resolution. Here an electro-hydrodynamic cell printing strategy is developed with microscale resolution (<100 µm) and high cellular viability (>95%). Unlike the existing electro-hydrodynamic cell jetting or printing explorations, insulating substrate is used to replace conventional semiconductive substrate as the collecting surface which significantly reduces the electrical current in the electro-hydrodynamic printing process from milliamperes (>0...
November 2, 2017: Small
Vidhubala Elangovan, Swaminathan Rajaraman, Barsha Basumalik, Dhivya Pandian
Purpose: Cancer-related stigma influences the way people perceive cancer, which renders cancer control-beginning with prevention and proceeding to palliation-a challenging task. This study aimed to assess the current levels of awareness and perceptions about cancer among people with various socioeconomic status and diverse backgrounds in the city of Chennai, India. Patients and Methods: The sample population (N = 2,981; 18 to 88 years of age) was stratified into four groups: patients (n = 510), caregivers (n = 494) consulting at the Cancer Institute (Women Indian Association), college students (n = 978), and general public (n = 999)...
October 2017: Journal of Global Oncology
Emily R Spitzer, Michelle L Hughes
BACKGROUND: Contemporary cochlear implants (CIs) use cathodic-leading, symmetrical, biphasic current pulses, despite a growing body of evidence that suggests anodic-leading pulses may be more effective at stimulating the auditory system. However, since much of this research on humans has used pseudomonophasic pulses or biphasic pulses with unusually long interphase gaps, the effects of stimulus polarity are unclear for clinically relevant (i.e., symmetric biphasic) stimuli. PURPOSE: The purpose of this study was to examine the effects of stimulus polarity on basic characteristics of physiological spread-of-excitation (SOE) measures obtained with the electrically evoked compound action potential (ECAP) in CI recipients using clinically relevant stimuli...
October 2017: Journal of the American Academy of Audiology
Georgios Lymperopoulos, Panagiotis Lymperopoulos, Victoria Alikari, Chrisoula Dafogianni, Sofia Zyga, Nikoletta Margari
Electrical Impedance Tomography (EIT) is a promising application that displays changes in conductivity within a body. The basic principle of the method is the repeated measurement of surface voltages of a body, which are a result of rolling injection of known and small-volume sinusoidal AC current to the body through the electrodes attached to its surface. This method finds application in biomedicine, biology and geology. The objective of this paper is to present the applications of Electrical Impedance Tomography, along with the method's capabilities and limitations due to the electrical properties of the human body...
2017: Advances in Experimental Medicine and Biology
Richard Janissen, Prasana K Sahoo, Clelton A Santos, Aldeliane M da Silva, Antonio A G von Zuben, Denio E P Souto, Alexandre D T Costa, Paola Celedon, Nilson I T Zanchin, Diogo B Almeida, Douglas S Oliveira, Lauro T Kubota, Carlos L Cesar, Anete P de Souza, Monica A Cotta
Electrically active field-effect transistors (FET) based biosensors are of paramount importance in life science applications, as they offer direct, fast, and highly sensitive label-free detection capabilities of several biomolecules of specific interest. In this work, we report a detailed investigation on surface functionalization and covalent immobilization of biomarkers using biocompatible ethanolamine and poly(ethylene glycol) derivate coatings, as compared to the conventional approaches using silica monoliths, in order to substantially increase both the sensitivity and molecular selectivity of nanowire-based FET biosensor platforms...
October 11, 2017: Nano Letters
Ann Hallemans, Griet Mertens, Paul Van de Heyning, Vincent Van Rompaey
HYPOTHESIS: Auditory information through an active cochlear implant (CI) influences gait parameters in adults with bilateral caloric areflexia and profound sensorineural hearing loss. BACKGROUND: Patients with bilateral caloric areflexia suffer from imbalance, resulting in an increased risk of falling. In case of simultaneous deafness, the lack of auditory feedback results in less awareness of the auditory scene. This combination might produce significant challenges while walking and navigating...
2017: Frontiers in Neurology
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