Reversible Conduction Block in Peripheral Mammalian Nerve Using Low Frequency Alternating Current*

2019 ◽  
Author(s):  
Landan M Mintch ◽  
Ivette Muzquiz ◽  
M. Ryne Horn ◽  
Michael Carr ◽  
John H. Schild ◽  
...  
Keyword(s):  
Conduction Block ◽  
Low Frequency ◽  
Alternating Current ◽  
Mammalian Nerve

scholarly journals A Reversible Low Frequency Alternating Current Nerve Conduction Block Applied to Mammalian Autonomic Nerves

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4521
Author(s):  
M. Ivette Muzquiz ◽  
Landan Mintch ◽  
M. Ryne Horn ◽  
Awadh Alhawwash ◽  
Rizwan Bashirullah ◽  
...  
Keyword(s):  
Nervous System ◽  
Nerve Block ◽  
Nerve Conduction ◽  
Conduction Block ◽  
Low Frequency ◽  
Alternating Current ◽  
Autonomic Nerves ◽  
Pt Black ◽  
Pulse Stimulation ◽  
Nerve Conduction Block

Electrical stimulation can be used to modulate activity within the nervous system in one of two modes: (1) Activation, where activity is added to the neural signalling pathways, or (2) Block, where activity in the nerve is reduced or eliminated. In principle, electrical nerve conduction block has many attractive properties compared to pharmaceutical or surgical interventions. These include reversibility, localization, and tunability for nerve caliber and type. However, methods to effect electrical nerve block are relatively new. Some methods can have associated drawbacks, such as the need for large currents, the production of irreversible chemical byproducts, and onset responses. These can lead to irreversible nerve damage or undesirable neural responses. In the present study we describe a novel low frequency alternating current blocking waveform (LFACb) and measure its efficacy to reversibly block the bradycardic effect elicited by vagal stimulation in anaesthetised rat model. The waveform is a sinusoidal, zero mean(charge balanced), current waveform presented at 1 Hz to bipolar electrodes. Standard pulse stimulation was delivered through Pt-Black coated PtIr bipolar hook electrodes to evoke bradycardia. The conditioning LFAC waveform was presented either through a set of CorTec® bipolar cuff electrodes with Amplicoat® coated Pt contacts, or a second set of Pt Black coated PtIr hook electrodes. The conditioning electrodes were placed caudal to the pulse stimulation hook electrodes. Block of bradycardic effect was assessed by quantifying changes in heart rate during the stimulation stages of LFAC alone, LFAC-and-vagal, and vagal alone. The LFAC achieved 86.2±11.1% and 84.3±4.6% block using hook (N = 7) and cuff (N = 5) electrodes, respectively, at current levels less than 110 µAp (current to peak). The potential across the LFAC delivering electrodes were continuously monitored to verify that the blocking effect was immediately reversed upon discontinuing the LFAC. Thus, LFACb produced a high degree of nerve block at current levels comparable to pulse stimulation amplitudes to activate nerves, resulting in a measurable functional change of a biomarker in the mammalian nervous system.

scholarly journals Low-frequency alternating current stimulation rhythmically suppresses gamma-band oscillations and impairs perceptual performance

NeuroImage ◽  
2019 ◽  
Vol 184 ◽  
pp. 440-449 ◽  
Author(s):  
Jim D. Herring ◽  
Sophie Esterer ◽  
Tom R. Marshall ◽  
Ole Jensen ◽  
Til O. Bergmann
Keyword(s):  
Low Frequency ◽  
Alternating Current ◽  
Gamma Band ◽  
Perceptual Performance ◽  
Gamma Band Oscillations

An electrosurgical technique for the production of localized tissue ablations in the early chick embryo

Development ◽  
1971 ◽  
Vol 26 (1) ◽  
pp. 21-29
Author(s):  
R. K. Jordan
Keyword(s):  
Chick Embryo ◽  
Low Frequency ◽  
Alternating Current ◽  
Chick Embryos ◽  
Operating Microscope ◽  
Young Chick ◽  
Early Chick Embryo ◽  
Electrolytic Corrosion ◽  
Tungsten Metal

The passage of low-frequency alternating current was found superior to other methods considered for the production of small, discrete, electrolytic ablations in young chick embryos. Active electrodes of tungsten metal less than 5 µm in diameter were prepared by controlled electrolytic corrosion. These gave reproducible, discrete foci of destruction of the required size, with currents less than 2 mA. The identification of destroyed tissue areas was immediately apparent under the operating microscope and confirmed histologically. Preliminary studies on bilateral extirpation of the ultimobranchial primordia show the absence of the ultimobranchial bodies 6 days after destruction of the primordia at 96 h of incubation.

scholarly journals The ignition of gases by condenser discharge sparks

1914 ◽  
Vol 91 (623) ◽  
pp. 17-22 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
High Temperature ◽  
Low Frequency ◽  
Spark Ignition ◽  
Alternating Current ◽  
Characteristic Type ◽  
Current Break ◽  
Continuous Current ◽  
Parabolic Form

1.It may be taken as an axiom of electrical ignition that the closer its conditions resemble those in the explosion wave front the more readily will it occur. These conditions are high temperature and pressure, and in the case of hydrocarbons combustion to carbon monoxide. They are also characteristic of condenser discharge sparks, for in the first place the surface of a platinum pole to which condenser discharge has been made becomes pitted to a remarkable extent, greater than when large currents are broken by separation of the poles. The sparks have therefore a high temperature. That they give rise to high gas pressure is clear from the intensity of the sound of a single spark discharge, and finally it will be shown that combustion to carbon monoxide rather than to carbon dioxide is peculiar in certain cases to ignition by capacity sparks. In addition to these the sparks are of very short duration, are oscillatory in character, and start with ionisation or breakdown of the gas between the poles. The belief that all visible sparks will ignite explosive mixtures no doubt arose from observations of the activity of condenser discharge in this respect, but while in certain cases, especially in the ignition of hydrogen, the least is in every case a well marked limit to their igniting power, and as the percentage of gas limits of inflammability are approached they require to be large. 2. The Paraffins—Ethane, Propane, and Butane .—The gases used in the present work were from the same stocks as those used for break-spark ignition. The results obtained from them are given in fig. 1. They have two interesting features; their minimum igniting current is the same in every case, in this resembling their ignition by continuous current break-sparks, but they have the parabolic form characteristic of alternating current break-spark ignition. Ethane has, however, a minimum at 7∙7 per cent., the point of combustion to carbon monoxide, the others, as before, midway between this and combustion to carbon dioxide. There is, however, on the higher side of the ethane and propane curves—the supply of butane gave out before this could be examined fully—a step or increase in difficulty of ignition corresponding to mixtures midway between four and five atoms of oxygen to one molecule of ethane, and between six and seven to one of propane. This point was thought to be some failure in the quality of the gas, but when it appeared in both, and to a still greater extent in methane, it was more fully examined. Condenser-spark ignition has therefore some of the features of both continuous and low frequency alternating current break-spark ignition, but it has a characteristic type of its own.

Microstructure Evolution During Alternating-Current-Induced Fatigue

Materials ◽  
2004 ◽  
Author(s):  
R. R. Keller ◽  
R. H. Geiss ◽  
Y.-W. Cheng ◽  
D. T. Read
Keyword(s):  
Electron Backscatter Diffraction ◽  
Failure Process ◽  
Low Frequency ◽  
Surface Damage ◽  
Alternating Current ◽  
Fiber Texture ◽  
Electrical Failure ◽  
Damage Process ◽  
Current Densities ◽  
Interconnect Lines

Subjecting electronic interconnect lines to high-density, low-frequency alternating current creates cyclic thermomechanical stresses that eventually cause electrical failure. A detailed understanding of the failure process could contribute to both prevention and diagnostics. We tested unpassivated Al-1Si traces on the NIST-2 test chip; these are 3.5 μm wide by 0.5 μm thick by 800 μm long, with a strong (111) as-deposited fiber texture and an initial average grain diameter of approximately 1 μm. We applied rms current densities of 11.7 to 13.2 MA/cm2 at 100 Hz. Resistance changes in the lines indicated that such current densities produce temperature cycles at 200 Hz with amplitude exceeding 100 K. Open circuits occurred in under 10 minutes, with substantial surface damage seen after only one minute. A few failures initiated at lithography defects initially present in the lines, but most were produced by the current alone. In one detailed example presented in this paper, we monitored the damage process by interrupting the current at 10, 20, 40, 80, 160, and 320 s in order to characterize an entire line by scanning electron microscopy and automated electron backscatter diffraction (EBSD); failure took place after 697 s. Results are described in terms of deformation, grain growth, and orientation changes.

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