Alternating Current Impedance Imaging of High-Resistance Membrane Pores Using a Scanning Electrochemical Microscope. Application of Membrane Electrical Shunts To Increase Measurement Sensitivity and Image Contrast

2006 ◽  
Vol 78 (18) ◽  
pp. 6535-6541 ◽  
Author(s):  
Eric Nathan Ervin ◽  
Henry S. White ◽  
Lane A. Baker ◽  
Charles R. Martin
Keyword(s):  
High Resistance ◽  
Alternating Current ◽  
Image Contrast ◽  
Measurement Sensitivity ◽  
Membrane Pores ◽  
Impedance Imaging ◽  
Scanning Electrochemical Microscope

scholarly journals ELECTRIC IMPEDANCE OF FERTILIZED ARBACIA EGG SUSPENSIONS

1938 ◽  
Vol 21 (5) ◽  
pp. 583-590 ◽  
Author(s):  
Kenneth S. Cole ◽  
Joseph M. Spencer
Keyword(s):  
Plasma Membrane ◽  
High Resistance ◽  
Sea Water ◽  
High Capacity ◽  
Low Frequency ◽  
Alternating Current ◽  
Electric Impedance ◽  
Perivitelline Space ◽  
Membrane Capacity ◽  
Fertilization Membrane

From the low frequency alternating current impedance and the volume concentrations of suspensions of Arbacia eggs, it is shown that the high resistance membrane is either at or very near the plasma membrane for both unfertilized and fertilized eggs, and that the specific resistances of the perivitelline space and fertilization membrane are not greatly different from that of sea water. The effect of the capacity element which appears after fertilization at intermediate frequencies is considerably less than in the earlier experiments on Arbacia and Hipponoë eggs. These findings indicate that the fertilization membrane does not have the high capacity previously attributed to it and that the increase in membrane capacity takes place at or near the plasma membrane.

scholarly journals Effect of decreasing electrical resistance in Characeae cell membranes caused by the flow of alternating current

2014 ◽  
Vol 63 (3-4) ◽  
pp. 269-273
Author(s):  
Edward Śpiewla ◽  
Małgorzata Tokarska-Schlattner
Keyword(s):  
Activation Energy ◽  
Potassium Channels ◽  
High Resistance ◽  
Electrical Resistance ◽  
Cell Membranes ◽  
Alternating Current ◽  
Increasing Temperature

By means of the techniques of external electrodes and microelectrodes, it was found that evanescent flow of an alternating current through plasmalemma of <i>Characeae</i> cells neutralises oscillatory change in their electrical resistance and reversibly diminishes its value. This effect is particularly significant in the case of "high resistance cells", but it weakens with increasing temperature. The value of the estimated activation energy indicates that, after flow of the alternating current through the membrane, a rapid increase in the conductivity may be caused by an increase in conductivity of potassium channels. This result seems to support the hypothesis of electroconformational feedback.

scholarly journals Hydrogen mapping in an aluminum alloy using an alternating current scanning electrochemical microscope (AC-SECM)

2017 ◽  
Vol 80 ◽  
pp. 29-32 ◽  
Author(s):  
Manon Chloé Lafouresse ◽  
Marie-Laetitia de Bonfils-Lahovary ◽  
Lydia Laffont ◽  
Christine Blanc
Keyword(s):  
Aluminum Alloy ◽  
Alternating Current ◽  
Scanning Electrochemical Microscope

scholarly journals Sources of error in AC measurement of skin conductance

2019 ◽  
Vol 6 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Ørjan G.Martinsen ◽  
Oliver Pabst ◽  
Christian Tronstad ◽  
Sverre Grimnes
Keyword(s):  
Skin Conductance ◽  
Electrodermal Activity ◽  
Alternating Current ◽  
Measurement Sensitivity ◽  
Measurement Frequency ◽  
Sources Of Error ◽  
Physiological Information ◽  
Ac Measurement

Abstract Alternating current methods have the potential to improve the measurement of electrodermal activity. However, there are pitfalls that should be avoided in order to perform these measurements in a correct manner. In this paper, we address issues like the choice of measurement frequency, placement of electrodes and the kind of electrodes used. Ignoring these factors may result in loss of measurement sensitivity or erroneous measurements with artifacts that contain little or no physiological information.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

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