scholarly journals Motility of cultured fish epidermal cells in the presence and absence of direct current electric fields.

1986 ◽  
Vol 102 (4) ◽  
pp. 1384-1399 ◽  
Author(s):  
M S Cooper ◽  
M Schliwa
Keyword(s):  
Membrane Potential ◽  
Electric Field ◽  
Electric Fields ◽  
Direct Current ◽  
Epidermal Cells ◽  
Resting Membrane Potential ◽  
Cell Clusters ◽  
Cell Locomotion ◽  
Presence And Absence ◽  
Dc Electric Fields

The motile behavior and cytoskeletal structures of fish epidermal cells (keratocytes) in the presence and absence of direct current (DC) electric fields were examined. These cells spontaneously show highly directional locomotion in culture, migrating at rates of up to 1 micron/s. When DC electric fields between 0.5 and 15 V/cm are applied, single epidermal cells as well as cell clusters and cell sheets migrate towards the cathode. Cell clusters and sheets break apart into single migratory cells in the upper range of these field strengths. Cell shape and morphology are unaltered when the keratocytes are guided by an electric field. Neither the spontaneous locomotion nor the electrically guided motility were found to be microtubule dependent. 1 mM La3+, 10 mM Co2+, 50 microM verapamil, and 50 microM nitrendipine (calcium channel antagonists) reversibly inhibited lamellipod formation and cell locomotion in both spontaneously migrating and electrically guided cells. Ciba-Geigy Product 28392, which stimulates the opening of calcium channels, and is a competitive inhibitor of nitrendipine, has no effect on the locomotion of keratocytes. Cell motility was also unaffected by hyperpolarizing and depolarizing (low and high K+) media. It is argued that while a tissue cell may accommodate changes in resting membrane potential without becoming more or less motile, the cell may not be able to counterbalance the effects of depolarization and hyperpolarization simultaneously. In this context, a gradient of membrane potential, which is induced by an external DC electric field, will serve as a persistent stimulus for cell locomotion.

Pulsed DC electric fields couple to natural NAD(P)H oscillations in HT-1080 fibrosarcoma cells

2001 ◽  
Vol 114 (8) ◽  
pp. 1515-1520 ◽  
Author(s):  
A.J. Rosenspire ◽  
A.L. Kindzelskii ◽  
H.R. Petty
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Cell Function ◽  
Low Frequency ◽  
Reactive Oxygen Metabolites ◽  
Pulsed Dc ◽  
Fibrosarcoma Cells ◽  
Chemotactic Factors ◽  
Oxygen Metabolites ◽  
Dc Electric Fields

Previously, we have demonstrated that NAD(P)H levels in neutrophils and macrophages are oscillatory. We have also found that weak ultra low frequency AC or pulsed DC electric fields can resonate with, and increase the amplitude of, NAD(P)H oscillations in these cells. For these cells, increased NAD(P)H amplitudes directly signal changes in behavior in the absence of cytokines or chemotactic factors. Here, we have studied the effect of pulsed DC electric fields on HT-1080 fibrosarcoma cells. As in neutrophils and macrophages, NAD(P)H levels oscillate. We find that weak (~10(-)(5) V/m), but properly phased DC (pulsed) electric fields, resonate with NAD(P)H oscillations in polarized and migratory, but not spherical, HT-1080 cells. In this instance, electric field resonance signals an increase in HT-1080 pericellular proteolytic activity. Electric field resonance also triggers an immediate increase in the production of reactive oxygen metabolites. Under resonance conditions, we find evidence of DNA damage in HT-1080 cells in as little as 5 minutes. Thus the ability of external electric fields to effect cell function and physiology by acting on NAD(P)H oscillations is not restricted to cells of the hematopoietic lineage, but may be a universal property of many, if not all polarized and migratory eukaryotic cells.

scholarly journals Electric field induced gelation in aqueous nanoclay suspensions

Soft Matter ◽  
2018 ◽  
Vol 14 (34) ◽  
pp. 6974-6982 ◽  
Author(s):  
Paramesh Gadige ◽  
Ranjini Bandyopadhyay
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Soft Solids ◽  
Clay Suspensions ◽  
Dc Electric Fields

Liquid-like aqueous colloidal LAPONITE® clay suspensions rapidly transform into soft solids due to the application of DC electric fields.

Effects of DC electric fields on neuronal excitability: A bifurcation analysis

2014 ◽  
Vol 28 (18) ◽  
pp. 1450114 ◽  
Author(s):  
Yanqiu Che ◽  
Huiyan Li ◽  
Chunxiao Han ◽  
Xile Wei ◽  
Bin Deng ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Parameter Space ◽  
Bifurcation Analysis ◽  
Neural Control ◽  
Neuronal Excitability ◽  
Modulation Method ◽  
Two Dimensional ◽  
Dimensional Parameter ◽  
Dc Electric Fields

In this paper, the effects of external DC electric fields on the neuro-computational properties are investigated in the context of Morris–Lecar (ML) model with bifurcation analysis. We obtain the detailed bifurcation diagram in two-dimensional parameter space of externally applied DC current and trans-membrane potential induced by external DC electric field. The bifurcation sets partition the two-dimensional parameter space in terms of the qualitatively different behaviors of the ML model. Thus the neuron's information encodes the stimulus information, and vice versa, which is significant in neural control. Furthermore, we identify the electric field as a key parameter to control the transitions among four different excitability and spiking properties, which facilitates the design of electric fields based neuronal modulation method.

Effects of sodium on beta-cell electrical activity

1982 ◽  
Vol 242 (5) ◽  
pp. C296-C303 ◽  
Author(s):  
B. Ribalet ◽  
P. M. Beigelman
Keyword(s):  
Membrane Potential ◽  
Action Potential ◽  
Beta Cell ◽  
Pancreatic Beta Cell ◽  
Input Resistance ◽  
Resting Membrane Potential ◽  
Two Phase ◽  
Sodium Permeability ◽  
Potential Spike ◽  
Presence And Absence

The present studies, designed to evaluate the contribution of Na+ to the mouse pancreatic beta-cell membrane potential, were performed utilizing intracellular microelectrodes. Complete removal of external sodium, in the presence of glucose, did not significantly affect spike peak potential. However, it caused a negative shift of the resting membrane potential, both in the presence and absence of glucose. After this initial hyperpolarization, the membrane gradually depolarized, the rate of depolarization being slower in the absence of glucose. This two-phase hyperpolarization-depolarization pattern remained when ouabain was added, both in the presence and absence of glucose. An increase of input resistance was associated with the slow depolarization. During this depolarization the maximum rate of rise (dV/dtmax) of the action potential (“spike”) decreased. There was no direct relationship between dV/dtmax and [Na]0. Readdition of low [Na]0 (14 mM) to a glucose medium reactivated the postburst hyperpolarization (PBH), even in the presence of ouabain. These observations indicate that there is a significant resting sodium permeability (PNa). However, the action potential (spike) is not generated by activation of a voltage-dependent (gated) sodium channel. The membrane depolarization after Na+ removal reflects concomitant inhibition of the Na+-K+ pump and decrease of potassium permeability (PK). The blockage of PBH in the absence of Na+ is not related to the inhibition of an oscillatory Na+-K+ pump but to the inactivation of a PK. Aside from its effect on the Na+-K+ pump, ouabain may stimulate PNa.

Nonlinear whistler wave – electron interaction in the presence of direct current electric fields

1985 ◽  
Vol 63 (4) ◽  
pp. 479-482
Author(s):  
I. M. L. Das ◽  
R. P. Singh
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Direct Current ◽  
Relative Phase ◽  
Finite Amplitude ◽  
Angular Frequency ◽  
Whistler Wave ◽  
Electron Interaction ◽  
Direct Current Electric Field ◽  
Current Electric Field

The nonlinear interaction between an electron and a whistler wave propagating in a magnetoplasma has been studied and expressions for the resonance velocity, equilibrium relative phase angle, and the angular frequency of amplitude oscillations have been derived, taking into account the finite amplitude of the whistler wave, direct current electric field, and medium inhomogeneity. The parallel electric field and inhomogeneity cause detrapping of the particles.

Deformation of Nitrogen Bubbles in DC Electric Fields

2006 ◽  
Author(s):  
Feng Chen ◽  
Yao Peng ◽  
Yaozu Song ◽  
Min Chen
Keyword(s):  
Aspect Ratio ◽  
Electric Field ◽  
Electric Fields ◽  
Transformer Oil ◽  
Working Fluid ◽  
Direction Parallel ◽  
Electric Field Magnitude ◽  
Field Magnitude ◽  
Nitrogen Bubbles ◽  
Dc Electric Fields

The deformation of nitrogen bubbles in transformer oil with various DC electric fields was studied experimentally and theoretically. The bubble deformation was visualized by a high-speed digital camera. The major axis of the bubble was elongated along the direction parallel to the applied electric field, with the elongation increasing as the electric field magnitude increased. The electrical Weber number (We) was used to correlate the electric field magnitude and the electric permittivity of the working fluid to the bubble aspect ratio (AR). The experimental results indicate that the bubble aspect ratio increases with increasing We. The total electrical stresses were calculated on an actual bubble shape including the electrostriction stresses.

The Effect of Growth, Migration and Bacterial Cellulose Synthesis of Gluconacetobacter xylinus in Presence of Direct Current Electric Field Condition

2012 ◽  
Vol 550-553 ◽  
pp. 1108-1113 ◽  
Author(s):  
Lin Yan ◽  
Shi Ru Jia ◽  
Xin Tong Zheng ◽  
Cheng Zhong ◽  
Miao Liu ◽  
...  
Keyword(s):  
Electric Field ◽  
Bacterial Cellulose ◽  
Electric Fields ◽  
Direct Current ◽  
Cellulose Fiber ◽  
Sem Analysis ◽  
Cellulose Synthesis ◽  
Gluconacetobacter Xylinus ◽  
Growth State ◽  
Dc Electric Field

In this study, the movement and orientation of bacteria cells were controlled by direct current(DC) electric fields, result in altering alignment of bacterial cellulose nanofiber and further changing the 3-dimensional network structure of bacterial cellulose. A modified swarm plate assay was performed to investigate the migration of Gluconacetobacter xylinus cells which exposed in DC electric field. It suggested that the cells moved toward to negative pole and with the increasement of the electric field strength the velocity will also increase. The SEM analysis demonstrated that the cellulose fiber bundles which synthesized at 1V/cm have lager diameter and a trend toward one direction. Meanwhile the growth state of G.xylinus in the presence of DC electric field was also being observed.

Optical properties of nematic liquid crystal (C21H27NO2S) under AC/DC electric fields

2009 ◽  
Vol 87 (4) ◽  
pp. 293-298 ◽  
Author(s):  
Mehriban Emek ◽  
Nurettin Besli ◽  
Ahmet Yildirim ◽  
Suleyman Yilmaz
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Electric Field ◽  
Domain Structure ◽  
Nematic Liquid Crystal ◽  
Electric Fields ◽  
Transition Process ◽  
Optical Methods ◽  
Rotational Angle ◽  
Dc Electric Fields

In this study, the effects of the phase transition on the optical transmittance of the nematic liquid crystal C21H27NO2S, 4′-isothiocyanatophenyl-4-pentylbicyclo[2,2,2]octane-1-carboxylate are investigated in terms of temperature variation and rotational angle of the polarizer through electro-optical methods under AC / DC electric fields. It is observed that the domain structure of the material is affected considerably by the applied electric field as the temperature changes. Under applied electric fields, the crystal-nematic (CN) phase-transition point changes and the behaviour of the liquid crystal in the phase-transition region shows some differences. The intensity of the light passing through the system under a DC electric field increases as the electric field rises. Nevertheless, the intensity of the transmitted light under an AC electric field increases at the beginning and then decreases as the electric field rises to a temperature of more than 355 K. These results can be explained through the formation of a domain structure during the phase-transition process and the light scattering caused by these structures.

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