Treatment of Ionic Transport Processes in Electrolytic Conductivity by the Dynamic Frictional Formalism of Nonequilibrium Thermodynamics

1993 ◽  
Vol 97 (11) ◽  
pp. 1472-1477 ◽  
Author(s):  
Hans Vink
Keyword(s):  
Nonequilibrium Thermodynamics ◽  
Ionic Transport ◽  
Transport Processes ◽  
Electrolytic Conductivity

Characteristics of ionic transport processes in fish intestinal epithelial cells

Biosystems ◽  
1998 ◽  
Vol 45 (2) ◽  
pp. 123-140 ◽  
Author(s):  
Liviu Movileanu ◽  
Maria Luiza Flonta ◽  
Dan Mihailescu ◽  
Petre T. Frangopol
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Ionic Transport ◽  
Transport Processes ◽  
Intestinal Epithelial

scholarly journals Transport Processes in TlI and in the AgI-TlI-System

1974 ◽  
Vol 29 (5) ◽  
pp. 782-785
Author(s):  
A. Sdiiraldi ◽  
A. Magistris ◽  
E. Pezzati
Keyword(s):  
Electrical Conductivity ◽  
Transport Properties ◽  
Electronic Conductivity ◽  
Ionic Transport ◽  
Transport Processes ◽  
Silver Ion ◽  
Transport Numbers ◽  
Bond Ionicity ◽  
High Electronic Conductivity ◽  
High Silver

Abstract The transport properties of TlI and of the system AgI -TlI were investigated by measuring the electrical conductivity, σ , and the electronic and ionic transport numbers. A particularly high electronic conductivity was detected in β-TlI, while the a phase showed a predominant anionic contribution, as in TlCl and TlBr. The intermediate compounds, AgTl2I3 and AgTlI2, are silver ion conductors, but they exhibit low σ values. A comparison with other poliiodides, with a high silver ion conductivity, is suggested on the basis of the crystal bond ionicity.

The use of linear nonequilibrium thermodynamics in the study of renal physiology

1979 ◽  
Vol 236 (3) ◽  
pp. F211-F219
Author(s):  
A. Essig ◽  
S. R. Caplan
Keyword(s):  
Reflection Coefficient ◽  
Systematic Study ◽  
Nonequilibrium Thermodynamics ◽  
Flow System ◽  
Nonequilibrium Thermodynamic ◽  
Transport Processes ◽  
Renal Physiology ◽  
Onsager Reciprocity ◽  
Phenomenological Coefficients ◽  
Osmotic Pressure Difference

Classical formulations for the analysis of membrane transport processes, which ignored possible interactions between flows of diverse permeant species, often led to inconsistencies in the evaluation of permeability coefficients. For water flow induced by an osmotic pressure difference this difficulty was resolved by Staverman's introduction of the reflection coefficient sigma, a parameter which incorporates the interaction between solute and solvent in the course of their passage through a membrane. A comprehensive nonequilibrium thermodynamic (NET) formalism suitable for many biological systems was provided by Kedem and Katchalsky. For an n-flow system each flow is in general dependent on n forces; the assumption of Onsager reciprocity, however, reduces the number of independent phenomenological coefficients. Although NET is widely applied in the study of renal physiology, fundamental theoretical and practical problems remain. Basic considerations are the need to control or evaluate the influence of all coupled flows and to establish conditions fostering linear dependencies of flows on forces. When this is done a transport system may be characterized in terms of intrinsic membrane parameters, facilitating the systematic study of the effects of drugs, hormones, and various experimental perturbations.

scholarly journals Nonequilibrium Thermodynamics of Cell Signaling

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Enrique Hernández-Lemus
Keyword(s):  
Signal Transduction ◽  
Nonequilibrium Thermodynamics ◽  
Cellular Signaling ◽  
Second Messengers ◽  
Signal Transduction Pathway ◽  
Transport Processes ◽  
Life And Death ◽  
Fas Signaling ◽  
Intrinsic Fluctuations

Signal transduction inside and across the cells, also called cellular signaling, is key to most biological functions and is ultimately related with both life and death of the organisms. The processes giving rise to the propagation of biosignals are complex and extremely cooperative and occur in a far-from thermodynamic equilibrium regime. They are also driven by activation kinetics strongly dependent on local energetics. For these reasons, a nonequilibrium thermodynamical description, taking into account not just the activation of second messengers, but also transport processes and dissipation is desirable. Here we present a proposal for such a formalism, that considers cells as small thermodynamical systems and incorporates the role of fluctuations as intrinsic to the dynamics in a spirit guided by mesoscopic nonequilibrium thermodynamics. We present also a minimal model for cellular signaling that includes contributions from activation, transport, and intrinsic fluctuations. We finally illustrate its feasibility by considering the case of FAS signaling which is a vital signal transduction pathway that determines either cell survival or death by apoptosis.

Nonequilibrium thermodynamics of transport processes on membrane surfaces

2016 ◽  
Vol 78 (5) ◽  
pp. 652-657 ◽  
Author(s):  
V. I. Roldughin ◽  
V. M. Zhdanov ◽  
T. V. Kharitonova
Keyword(s):  
Nonequilibrium Thermodynamics ◽  
Transport Processes ◽  
Membrane Surfaces

scholarly journals Ionic Transport Processes

2008 ◽  
Author(s):  
Kyösti Kontturi ◽  
Lasse Murtomäki ◽  
José A. Manzanares
Keyword(s):  
Ionic Transport ◽  
Transport Processes

scholarly journals The effects of cyanobacteria and the cyanobacterial toxin microcystin-LR on Ca2+ transport and Na+/K+-ATPase in tilapia gills

1996 ◽  
Vol 199 (6) ◽  
pp. 1319-1326
Author(s):  
N Bury ◽  
G Flik ◽  
F Eddy ◽  
G Codd
Keyword(s):  
Membrane Vesicles ◽  
Ionic Transport ◽  
Transport Processes ◽  
Whole Body ◽  
Inhibitory Effects ◽  
Plasma Membrane Vesicles ◽  
Cyanobacterial Toxin ◽  
Physiological Processes ◽  
Basolateral Plasma Membrane ◽  
P Type

The effects of cytotoxic substances from cyanobacteria on ionic transport processes in tilapia (Oreochromis mossambicus) were examined. Inhibitory effects on ionic transport including whole-body Ca2+ fluxes and P-type ATPases of the gill were found. The compounds tested were (1) purified microcystin-LR (MC-LR), a heptapeptide hepatotoxin produced by the cyanobacterium Microcystis aeruginosa, (2) extracts from M. aeruginosa strain PCC 7820, a strain producing MC-LR and other microcystin variants, and (3) extracts of M. aeruginosa CYA 43, a strain producing toxins including small quantities of MC-LR. Whole-body Ca2+ influx was inhibited by a 24 h exposure to extracts of M. aeruginosa CYA 43 and 7820, but not by exposure to an equivalent amount (90 mg l-1) of purified MC-LR. Shorter exposure times (4 h) were ineffective. Fish exposed to extracts from M. aeruginosa CYA 43 showed significant plasma hypocalcaemia. Both strains of M. aeruginosa inhibited Ca2+ uptake by basolateral plasma membrane vesicles (BLMVs), endoplasmic reticulum (ER) and mitochondria, as well as BLMV K+-dependent p-nitrophenol phosphatase (pNPPase) activity. The hydrophobic fractions of the cyanobacterial extracts were the most potent, inhibiting BLMV, ER and mitochondrial Ca2+ uptake by up to 99 %, but they were less inhibitory of BLMV K+-dependent pNPPase activity. Purified MC-LR was without effect on these preparations. In conclusion, cytotoxic substances from cyanobacteria have the potential to disrupt normal physiological processes dependent upon Ca2+ transport processes in tilapia gills.

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