Compositional constraints to identifying ternary interactions in ion‐exchange equilibria: an example of potassium influence on ammonium‐calcium exchange on vermiculite

1969 ◽

Vol 54 (4) ◽

pp. 494-511 ◽

Cited By ~ 9

Author(s):

Gerald R. Little ◽

William W. Sleator

Keyword(s):

Steady State ◽

Ion Exchange ◽

Guinea Pig ◽

Extracellular Space ◽

Entry Rate ◽

Steady State Condition ◽

Peak Tension ◽

Guinea Pig Atrium ◽

Calcium Exchange ◽

The Difference

A Krebs-Henseleit (KH) medium made hypertonic by adding nonpermeant molecules substantially increased the isometric peak tension at steady-state contractions below 3 per sec in guinea pig atrium at 27°C. Action potential durations were decreased. KH plus 100 mM raffinose or sucrose resulted in similar and nearly maximal changes which were essentially reversible upon return to normal KH. When one active contracting atrium was used to passively stretch a second atrium, the difference in Ca ion exchange (1 min exchange with the extracellular space) between active and stretched atria significantly increased at 1 per sec and at 2 per sec in going from normal to 100 mM hypertonic KH. The calculated mean Ca ion cellular exchange per beat per 100 g of cells (a) doubled in changing from normal to 100 mM hypertonic KH, and (b) decreased slightly in changing from contractions of 1 per sec to 2 per sec in normal KH. These data are consistent with the hypothesis (a) that Ca ion entry per beat from the extracellular space is proportional to membrane depolarized time with a constant medium and a steady-state condition, and the hypothesis (b) that 100 mM hypertonicity doubles the Ca ion entry rate during depolarization. These data enable rejection of the hypothesis that the peak tension is proportional to the Ca ion entry per beat from the extracellular space under steady-state conditions, and suggest that any additional Ca ion involved in the larger contractions at higher frequencies comes from an increase in Ca ion available from intracellular stores.

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On the existence of ternary interactions in ion exchange

AIChE Journal ◽

10.1002/aic.690340425 ◽

1988 ◽

Vol 34 (4) ◽

pp. 702-703

Author(s):

Charles N. Haas

Keyword(s):

Ion Exchange ◽

Ternary Interactions

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Calcium Exchange Diffusion in a Porous Phospholipid Ion-exchange Membrane

Nature ◽

10.1038/223898a0 ◽

1969 ◽

Vol 223 (5209) ◽

pp. 898-900 ◽

Cited By ~ 35

Author(s):

D. VAN BREEMEN ◽

C. VAN BREEMEN

Keyword(s):

Ion Exchange ◽

Ion Exchange Membrane ◽

Exchange Diffusion ◽

Calcium Exchange ◽

Exchange Membrane

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Embedding Procedure for Water Swollen Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006951x ◽

1970 ◽

Vol 28 ◽

pp. 504-505

Author(s):

Ann M. Thomas ◽

Virginia Shemeley

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Ion Exchange ◽

Structural Changes ◽

Cross Linking ◽

Ion Exchange Resins ◽

Transmission Electron ◽

First Pass ◽

Exchange Resins

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.

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