Molecular Hysteresis and Its Cybernetic Significance

Neumann, Eberhard

doi:10.1002/anie.197303561

Cited by 73 publications

(25 citation statements)

References 43 publications

(1 reference statement)

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“…) reduction of Z 2 , is unstable and can isomerize to Z 1 . When electron transfer is rapid compared to the structural change, reversible potentials E 1 and E 2 can be measured.…”

Section: Linkage Isomerizations Induced By Electrochemical Processesmentioning

confidence: 98%

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Molecular Hysteresis by Linkage Isomerizations Induced by Electrochemical Processes

Sano

2001

Molecular Machines and Motors

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The redox behavior of [Ru(NH 3 ) 5 S ® O induced by electrochemical processes are reviewed. The properties of molecules speci®cally designed to exhibit a hysteresis loop on being addressed electrochemically are described. These molecules comprise a combination of two Ru 3+ /Ru 2+ couples, one with the metal attached to an electrochemically reversible group and the other with the metal attached to the sulfoxide by a bridging ligand. Their redox and kinetic behaviors are presented and their memory lives are determined as the rates of the conversions between two isomeric intermediate states. Reading out the memory by intervalence bands is also discussed. Some considerations are also presented for linkage isomerizations and molecular hysteresis.

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“…) reduction of Z 2 , is unstable and can isomerize to Z 1 . When electron transfer is rapid compared to the structural change, reversible potentials E 1 and E 2 can be measured.…”

Section: Linkage Isomerizations Induced By Electrochemical Processesmentioning

confidence: 98%

“…Neumann [2] ®rst used the term``molecular hysteresis'' to describe the phenomenon which was hysteresis on precipitation and dissolution of the polymers in pH changes of aqueous solutions. However, because segments of the molecules interact, as do molecules in condensed form, the hysteresis he describes is still a collective phenomenon.…”

Section: Introductionmentioning

confidence: 99%

Molecular Hysteresis by Linkage Isomerizations Induced by Electrochemical Processes

Sano

2001

Molecular Machines and Motors

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“…Dielectric measurements have shown that polypeptides in viscous organic solvents may undergo intramolecular helix-coil transitions in the presence of electric fields (Schwarz and Seelig, 1968). In the meantime there are many reports on fieldinduced conformational chanoes in multi-stranded as well as in single-stranded polyelectrolytes (Neumann and Katchalsky, 1972;Neumann, 1973;Kikuchi andYoshioka, 1973, 1976;Yasunaga et al, 1973;Revzin and Neumann, 1974;Prrschke, 1974Prrschke, , 1976Prrschke, , 1985.…”

Section: Biopolymersmentioning

confidence: 99%

Chemical electric field effects in biological macromolecules

Neumann

1986

Progress in Biophysics and Molecular Biology

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“…This assumption, known as the "quasi-steady-state hypothesis,"8 allows one to solve for the current distribution in a resistive-capacitive circuit representing the excitable membrane (see Appendix). 4 (1) where I is the current injected through the suction pipette. All those terms have been measured in previous experiments."…”

Section: Materials and Methods Experimental Studiesmentioning

confidence: 99%

“…Substituting (tu)n for (tu),1, in Equation 2 gives the recovery time for the (n+l)th beat (t)n+1, and thus (tU)n+, can be predicted, and so forth. If a dropped beat occurs, this allows for prolongation of the recovery time one full cycle and thus (4) where (tu), l is the latency of the last successful beat.…”

Section: Materials and Methods Experimental Studiesmentioning

confidence: 99%

Hysteresis in the excitability of isolated guinea pig ventricular myocytes.

Lorente

Delgado

Delmar

et al. 1991

Circulation Research

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Hysteresis phenomena were demonstrated in the excitability of single, enzymatically dissociated guinea pig ventricular myocytes. Membrane potentials were recorded with patch pipettes in the whole-cell current-clamp configuration. Repetitive stimulation with depolarizing current pulses of constant cycle length and duration but varying strength led to predictable excitation (1:1) and nonexcitation (1: 0) patterns depending on current strength. However, transition between patterns depended on the direction of current strength change, and stable hysteresis loops were obtained in stimulus-response pattern versus current strength plots in 31 cells. Increase of pulse duration and decrease of stimulation rate contributed to a reduction in hysteresis loop areas. In addition, at the abrupt transitions from 1:0 to 1:1 patterns, a latency adaptation phenomenon was consistently observed. Bath application of tetrodotoxin (30 ,M) produced no change of hysteresis, whereas hysteresis was substantially decreased in cobalt (2 mM) superfusion experiments. Analysis of the changes in amplitude and shape of the subthreshold responses during the transitions from one stable pattern to the other suggested that activity led to an increase in membrane resistance, particularly in the voltage domain between resting and threshold potentials. We therefore modeled the dynamic behavior of the single cells, using an analytical solution aimed at calculating the recovery of activation latency as a function of diastolic membrane resistance. Numerical iteration of the analytical model equations closely reproduced the experimental hysteresis loops in both qualitative and quantitative ways. The effect of stimulation frequency on the model was similar to the experimental findings. The overall study suggests that the excitability pattern of guinea pig ventricular myocytes is responsible for hysteresis and bistabilities when current intensity is allowed to fluctuate around threshold levels. (Circulation Research 1991;69:1301-

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Molecular Hysteresis and Its Cybernetic Significance

Cited by 73 publications

References 43 publications

Molecular Hysteresis by Linkage Isomerizations Induced by Electrochemical Processes

Molecular Hysteresis by Linkage Isomerizations Induced by Electrochemical Processes

Chemical electric field effects in biological macromolecules

Hysteresis in the excitability of isolated guinea pig ventricular myocytes.

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