scholarly journals Electrical Signs of New Membrane Production during Cleavage of Rana pipiens Eggs

1968 ◽  
Vol 52 (3) ◽  
pp. 509-531 ◽  
Author(s):  
Donald J. Woodward

Rana pipiens eggs dividing normally in diluted Ringer's solution show an increase in transmembrane potential inside negative, a decrease in resistance, and no change in total surface membrane capacitance at the appearance of a division furrow. Furrows of eggs in solutions with the tonicity of full Ringer develop partially, then regress so that the surface is again spherical. The potential and resistance changes are greater and substantial increases in capacitance occur when furrowing is so inhibited. It is proposed that the electrical changes at division are due to the introduction of new plasma membrane, between the blastomeres, having selective permeability to K and a low resistance compared to the outer spherical membrane. A narrow gap between blastomeres limits current flow through new membrane during normal division. A direct exposure of new membrane to the bathing medium when furrowing is disrupted results in larger changes in potential and resistance and permits the capacitance of new membrane to be detected.

2020 ◽  
Vol 6 (8(77)) ◽  
pp. 21-23
Author(s):  
S.N. Sarmasov ◽  
R.Sh. Rahimov ◽  
T.Sh. Abdullayev

The effect of oxygen adsorption on the conductivity of PbTe films is studied. Pn junctions based on PbTe films are photosensitive in the IR spectral region with a maximum photosensitivity of 𝜆𝑚𝑎𝑥 microns. The tunneling mechanism of current flow through the pn junction is shown.


Author(s):  
Ari Ramadhani

Abstract - Automatic system have grown widespread across all sector so do water heater. Traditionally, heating water is done by utilizing fire as heat source. As the growing of technology, the heating process could be done by manipulating electrical energy by convert it to heat. Electrical energy is flown to a metal rod that contact directly with the water which increase the water temperature. On some case, appropiate water temperature is needed. Altough, a thermometer is needed to read the actual temperature as a feedback value for the system and a system that can control the electricity current flow through the heater that the heat produced is linear to the current flow. With implementing microcontroller as a process node for generating PWM signal, this problem can be solved. Also, Labview is needed as an interface for monitoring and bursting an output which have been processed by Proportional, Integral, and Devivative (PID) controller to producing accurate and stable heat. Based on the results of testing, the system is able to provide a rapid response to any changes that occur, both changes in set-point and changes in water temperature (actual value). Another test is done by comparing the temperature value detected by the temperature sensor in this device with an external digital thermometer placed in the same place, and from some of the tests the temperature value detected by the temperature sensor in this device has a difference of ± 0.19 ℃ with a digital thermometer. Keyword : Water Heater, Thermometer, Microcontroller, LabView, PID.


Author(s):  
A.A. Belyaev ◽  
G.K. Beketov ◽  
G.E. Chaika ◽  
R.V. Konakova ◽  
V.G. Lyapin ◽  
...  
Keyword(s):  

2011 ◽  
Vol 82 (7) ◽  
pp. 073710 ◽  
Author(s):  
A. Maldonado ◽  
I. Guillamón ◽  
H. Suderow ◽  
S. Vieira

2014 ◽  
Vol 925 ◽  
pp. 300-303 ◽  
Author(s):  
Sharipah Nadzirah ◽  
Uda Hashim ◽  
N. Malihah

This research studies the properties of titanium dioxide (TiO2) nanoparticles synthesized by two different stabilizers via sol-gel method. Acetic and hydrochloric acids have been used as stabilizers to form two different TiO2 thin films. 100 μm gap of Al IDEs have been fabricated on each annealed TiO2 films. Finally the samples were physically and electrically characterized. Average crystallite sizes of the nanoparticles are 20 and 25 nm for acetic and hydrochloric acid respectively. The average current flow through the devices was extremely small which are around micro-to-nanoampere. It was found that the electrical conductivity increased significantly when particle sizes decreases.


2008 ◽  
Vol 4 (4) ◽  
pp. 307-317 ◽  
Author(s):  
Alexander Gow ◽  
Jerome Devaux

The insulative properties of myelin sheaths in the central and peripheral nervous systems (CNS and PNS) are widely thought to derive from the high resistance and low capacitance of the constituent membranes. Although this view adequately accounts for myelin function in large diameter fibers, it poorly reflects the behavior of small fibers that are prominent in many regions of the CNS. Herein, we develop a computational model to more accurately represent conduction in small fibers. By incorporating structural features that, hitherto, have not been simulated, we demonstrate that myelin tight junctions (TJs) improve saltatory conduction by reducing current flow through the myelin, limiting axonal membrane depolarization and restraining the activation of ion channels beneath the myelin sheath. Accordingly, our simulations provide a novel view of myelin by which TJs minimize charging of the membrane capacitance and lower the membrane time constant to improve the speed and accuracy of transmission in small diameter fibers. This study establishes possible mechanisms whereby TJs affect conduction in the absence of overt perturbations to myelin architecture and may in part explain the tremor and gait abnormalities observed in Claudin 11-null mice.


2020 ◽  
Vol 226 ◽  
pp. 115811 ◽  
Author(s):  
Thomas Busser ◽  
Marion Serres ◽  
Régis Philippe ◽  
Valérie Vidal

2014 ◽  
Vol 48 (4) ◽  
pp. 492-496 ◽  
Author(s):  
A. V. Sachenko ◽  
A. E. Belyaev ◽  
V. A. Pilipenko ◽  
T. V. Petlitskaya ◽  
V. A. Anischik ◽  
...  

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 47 ◽  
Author(s):  
Jan Lukas Storck ◽  
Timo Grothe ◽  
Al Mamun ◽  
Lilia Sabantina ◽  
Michaela Klöcker ◽  
...  

Electrospinning can be used to create nanofibers from diverse polymers in which also other materials can be embedded. Inclusion of magnetic nanoparticles, for example, results in preparation of magnetic nanofibers which are usually isotropically distributed on the substrate. One method to create a preferred direction is using a spinning cylinder as the substrate, which is not always possible, especially in commercial electrospinning machines. Here, another simple technique to partly align magnetic nanofibers is investigated. Since electrospinning works in a strong electric field and the fibers thus carry charges when landing on the substrate, using partly conductive substrates leads to a current flow through the conductive parts of the substrate which, according to Ampère’s right-hand grip rule, creates a magnetic field around it. We observed that this magnetic field, on the other hand, can partly align magnetic nanofibers perpendicular to the borders of the current flow conductor. We report on the first observations of electrospinning magnetic nanofibers on partly conductive substrates with some of the conductive areas additionally being grounded, resulting in partly oriented magnetic nanofibers.


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