Voltage dependent constituents

There are several hypotheses for a specific mechanism by which ONOO- can control the open state of the PTPC. Briefly the PTPC is regulated by primary constituents of the pore, including the inner membrane adenine nucleotide translocase (ANT) and the outer membrane protein voltage-dependent anion channel (VDAC or porin). The VDAC-ANT complex can bind to signaling proteins that modulate permeability transition, such as pro-apoptotic Bax (which opens the pore) and anti-apoptotic Bcl-2... 

In concluding this section, mention should be made concerning the dipoles of membrane constituents in the BLM. The dipole flip-flop could be important for the voltage-dependent conductance in BLM (e.g. alamethicin-modified BLM). Derzhanski et al. have derived an equation for the current as a function of frequencies. Pastushenko and Chizmadzhev have considered the energetic profile of dipole molecules in biomembranes in general, and in BLM in particular. This topic has been reviewed in detail by Shchipunov and Drachev, and by de Levie [3,15-24]. 

There are discrepancies in the amounts of harmful species tolerance that fuel cell developers establish, even for similar type fuel cells. These discrepancies are probably due to electrode design, microstructure differences, or in the way developers establish tolerance. There are some cases where the presence of certain harmful species causes immediate performance deterioration. More often, the degradation occurs over a long period of time, dependant on the developer s allowable voltage degradation rate on exposure to the specific harmful species. Here, the developer establishes an estimated cell life based on economics. The permissible amount of the harmful constituent is then determined based on its life effects. 

The tube is closed at one end. The reaction takes place all along the tube and consumes between 50 and 90% of constituents depending on experimental condition. The unreacted gases are burnt at the outlet of the fuel cell, enabling preheating of incoming gas. The voltage at the terminals of a cell is 0.5 to 0.8 V and the current of some hundreds of mA. The efficiency is approximately 50%. It increases if the system is under pressure. 

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