Mechanism of hydroxylamine mutagenesis: Role of tautomerism, conformation and proton exchange on base pairing between the promutagen N6 methoxyadenosine and uridine

1993 ◽  
Vol 46 (3) ◽  
pp. 207-215 ◽  
Author(s):  
Borys Kierdaszuk ◽  
Charlotta Johansson ◽  
Torbjorn Drakenberg ◽  
Ryszard Stolarski ◽  
David Shugar
Keyword(s):  
Proton Exchange ◽  
Base Pairing ◽  
Hydroxylamine Mutagenesis

Pancreatic beta-cell electrical activity: the role of anions and the control of pH

1983 ◽  
Vol 244 (3) ◽  
pp. C188-C197 ◽  
Author(s):  
G. T. Eddlestone ◽  
P. M. Beigelman
Keyword(s):  
Membrane Potential ◽  
Cell Membrane ◽  
Beta Cell ◽  
Pancreatic Beta Cell ◽  
Proton Exchange ◽  
Disulfonic Acid ◽  
Control Mechanisms ◽  
Exchange System ◽  
Sodium Proton Exchange

The influence of chloride on the mouse pancreatic beta-cell membrane potential and the cell membrane mechanisms controlling intracellular pH (pHi) have been investigated using glass microelectrodes to monitor the membrane potential. It has been shown that chloride is distributed passively across the beta-cell membrane such that chloride potential is equal to the membrane potential. Withdrawal of perifusate chloride or bicarbonate and the application of the drugs 4-acetamido-4'-isethiocyanostilbene-2,2'-disulfonic acid (SITS) and probenecid, both blockers of transmembrane anion movement, have been used to establish that a chloride-bicarbonate exchange system is operative in the cell membrane and that it is one of the control mechanisms of pHi. Amiloride, a specific blocker of the transmembrane sodium proton exchange, has been used to demonstrate that this mechanism is also operative in the beta-cell membrane in the control of pHi. The hypothesis that the calcium-activated potassium permeability is proton sensitive at an intracellular site, a fall in pHi causing a fall in permeability and an increase in pHi causing an increase in permeability, has been used to explain many of the effects observed in this study.

Predicting Liquid Water Saturation Through Differently Structured Cathode Gas Diffusion Media of a Proton Exchange Membrane Fuel Cell

2012 ◽  
Vol 9 (2) ◽  
Author(s):  
N. Akhtar ◽  
P. J. A. M. Kerkhof
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Proton Exchange Membrane ◽  
Water Saturation ◽  
Catalyst Layer ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Diffusion Media ◽  
Exchange Membrane

The role of gas diffusion media with differently structured properties have been examined with emphasis on the liquid water saturation within the cathode of a proton exchange membrane fuel cell (PEMFC). The cathode electrode consists of a gas diffusion layer (GDL), a micro-porous layer and a catalyst layer (CL). The liquid water saturation profiles have been calculated for varying structural and physical properties, i.e., porosity, permeability, thickness and contact angle for each of these layers. It has been observed that each layer has its own role in determining the liquid water saturation within the CL. Among all the layers, the GDL is the most influential layer that governs the transport phenomena within the PEMFC cathode. Besides, the thickness of the CL also affects the liquid water saturation and it should be carefully controlled.

scholarly journals Role of base pairing partner on DNA‐protein crosslinking from guanine oxidation

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Zitadel Anne Perez ◽  
Amanda Madison ◽  
Eric D. A. Stemp
Keyword(s):  
Base Pairing ◽  
Protein Crosslinking ◽  
Guanine Oxidation

A review on the role of proton exchange membrane on the performance of microbial fuel cell

2014 ◽  
Vol 25 (12) ◽  
pp. 1426-1432 ◽  
Author(s):  
Mostafa Rahimnejad ◽  
Gholamreza Bakeri ◽  
Mostafa Ghasemi ◽  
Alireza Zirepour
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Exchange Membrane

scholarly journals DFT Modeling of Organocatalytic Ring-Opening Polymerization of Cyclic Esters: A Crucial Role of Proton Exchange and Hydrogen Bonding

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2078 ◽  
Author(s):  
Ilya Nifant’ev ◽  
Pavel Ivchenko
Keyword(s):  
Ring Opening ◽  
Density Functional ◽  
Comparative Modeling ◽  
Ring Opening Polymerization ◽  
Proton Exchange ◽  
Dft Methods ◽  
Experimental Proof ◽  
Cyclic Esters ◽  
Dft Modeling

Organocatalysis is highly efficient in the ring-opening polymerization (ROP) of cyclic esters. A variety of initiators broaden the areas of organocatalysis in polymerization of different monomers, such as lactones, cyclic carbonates, lactides or gycolides, ethylene phosphates and phosphonates, and others. The mechanisms of organocatalytic ROP are at least as diverse as the mechanisms of coordination ROP; the study of these mechanisms is critical in ensuring the polymer compositions and architectures. The use of density functional theory (DFT) methods for comparative modeling and visualization of organocatalytic ROP pathways, in line with experimental proof of the structures of the reaction intermediates, make it possible to establish these mechanisms. In the present review, which continues and complements our recent manuscript that focused on DFT modeling of coordination ROP, we summarized the results of DFT modeling of organocatalytic ROP of cyclic esters and some related organocatalytic processes, such as polyester transesterification.

NUMERIAL INVESTIGATION OF THERMODIFFUSION EFFECTS ON PEM FUEL CELL PERFORMANCE

2010 ◽  
Vol 24 (13) ◽  
pp. 1329-1332 ◽  
Author(s):  
RIHAB JARALLA ◽  
JUN CAO ◽  
ZIAD SAGHIR
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Nonlinear Partial Differential Equations ◽  
Research Work ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Fuel Cell Performance ◽  
Electric Potentials ◽  
Exchange Membrane

An increasing amount of attention has been paid on the study of thermodiffusion effects on mass transport. This paper presents a novel mathematical model for an entire proton exchange membrane fuel cell (PEMFC) with focus placed on the modeling and assessment of the role of thermodiffusion that has been usually neglected in previous fuel cell research work. Built upon the equations of continuity, momentum, energy, species concentrations, and electric potentials in different regions of a PEMFC, a set of nonlinear partial differential equations are numerically solved using finite element methods. The simulation results demonstrate that the thermodiffusion has a noticeable impact on transport of species in an operational PEMFC.

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