Guidelines for Controlling Pore Radii From Nonlinear Analysis of a Two-Dimensional Model of Electroporation

2007 ◽  
Author(s):  
Jonathan P. Cranford ◽  
Xiaopeng Zhao ◽  
Wanda Krassowska
Keyword(s):  
Cell Membrane ◽  
Fixed Points ◽  
Pore Size ◽  
Nonlinear Analysis ◽  
Electric Pulse ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Electric Pulses ◽  
Two Dimensional Model

Electroporation, in which strong electric pulses create transient pores in the cell membrane, is commonly used as a method for delivering molecules into cells. One of the pulsing protocols used in practice, a two-pulse protocol, creates a certain number of pores (Num) with a short, large electric pulse, and then controls the pore size with a second, smaller electric pulse of strength V0. This study uses nonlinear analysis of an electroporation model to determine guidelines for the magnitude of V0 and Num that will produce pores of a desired radius (r). Analysis reveals that for Num between 85 and 3190, number and type of fixed points (FPs) depend on Num and V0. For this range of Num, there exist two stable FPs and one unstable FP, and increasing V0 beyond a certain threshold (V0th) drives the system to the FP with larger r. V0th can be fit to a function that is linearly dependent on Num. This study shows that for a given Num created by the first pulse, choice of V0 will allow the experimenter to optimize pore size for a specific application.

Commitment to pro- versus counter-attitudinal behavior and the dynamics of social representations

2002 ◽  
Vol 61 (1) ◽  
pp. 34-44 ◽  
Author(s):  
Eric Tafani ◽  
Lionel Souchet
Keyword(s):  
Higher Education ◽  
Social Representations ◽  
Cognitive Restructuring ◽  
Social Representation ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Social Actions ◽  
The Social ◽  
Two Dimensional Model ◽  
Students Attitudes

This research uses the counter-attitudinal essay paradigm ( Janis & King, 1954 ) to test the effects of social actions on social representations. Thus, students wrote either a pro- or a counter-attitudinal essay on Higher Education. Three forms of counter-attitudinal essays were manipulated countering respectively a) students’ attitudes towards higher education; b) peripheral beliefs or c) central beliefs associated with this representation object. After writing the essay, students expressed their attitudes towards higher education and evaluated different beliefs associated with it. The structural status of these beliefs was also assessed by a “calling into question” test ( Flament, 1994a ). Results show that behavior challenging either an attitude or peripheral beliefs induces a rationalization process, giving rise to minor modifications of the representational field. These modifications are only on the social evaluative dimension of the social representation. On the other hand, when the behavior challenges central beliefs, the same rationalization process induces a cognitive restructuring of the representational field, i.e., a structural change in the representation. These results and their implications for the experimental study of representational dynamics are discussed with regard to the two-dimensional model of social representations ( Moliner, 1994 ) and rationalization theory ( Beauvois & Joule, 1996 ).

Pulse Antennas: Accurate Solution of Two-Dimensional Model Problems for Structures with Gratings as Dispersive Elements

2001 ◽  
Vol 55 (8) ◽  
pp. 14
Author(s):  
A. I. Vyazmitinova ◽  
V. L. Pazynin ◽  
Andrei Olegovich Perov ◽  
Yurii Konstantinovich Sirenko ◽  
H. Akdogan ◽  
...  
Keyword(s):  
Accurate Solution ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Two Dimensional Model
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