Fuel Cell Using Squid Axon Electrolyte and Its Proton Conductivity

Fuel cells using biomaterials have the potential for environmentally friendly clean energy and have attracted a lot of interest. Moreover, biomaterials are expected to develop into in vivo electrical devices such as pacemakers with no side effects. Ion channels, which are membrane proteins, are known to have a fast ion transport capacity. Therefore, by using ion channels, the realization of fuel cell electrolytes with high-proton conductivity can be expected. In this study, we have fabricated a fuel cell using an ion channel electrolyte for the first time and investigated the electrical properties of the ion channel electrolyte. It was found that the fuel cell using the ion channel membrane shows a power density of 0.78 W/cm2 in the humidified condition. On the other hand, the power density of the fuel cell blocking the ion channel with the channel blocker drastically decreased. These results indicate that the fuel cell using the ion channel electrolyte operates through the existence of the ion channel and that the ion channel membrane can be used as the electrolyte of the fuel cell in humidified conditions. Furthermore, the proton conductivity of the ion channel electrolyte drastically increases above 85% relative humidity (RH) and becomes 2 × 10−2 S/m at 96% RH. This result indicates that the ion channel becomes active above 96%RH. In addition, it was deduced from the impedance analysis that the high proton conductivity of the ion channel electrolyte above 96% RH is caused by the activation of ion channels, which are closely related to the fractionalization of water molecule clusters. From these results, it was found that a fuel cell using the squid axon becomes a new fuel cell using the function of the ion channel above 96% RH.

Technical advances in neuroscience

This chapter highlights key technological advances in neuroimaging, the understanding of impulse transmission, and the molecular biology of the nervous system that have underpinned our modern understanding of the brain, mind, and nervous system. Neuroimaging spans the sub-cellular and systems levels of neuroscience, beginning with electron microscopy and then, 50 years later, magnetic resonance imaging and increasingly sophisticated mathematical modelling of brain function. These developments have been interleaved with the improved understanding of neurotransmission, starting with the seminal observations made from giant squid axon recordings, which were translated into clinically useable tools through the application of electric current, and later with magnetic stimulation. It is during the last 50 years that a molecular framework for these concepts emerged, with the cloning of genes that began in Duchenne muscular dystrophy, paving the way for the wider human genome project.

A model of ionic transport and osmotic volume control in cochlear outer hair cells

A computational model of the outer hair cell (OHC) of the mammalian cochlea is presented. It addresses the way in which movement of ions controls the cell shape and regulates pH. The model takes into account the possible chloride–bicarbonate exchange function of prestin, a protein highly expressed in the plasma membrane of OHCs. A model of intracellular pH transients following the imposition of a rapid acid load upon the cell has been adapted from the squid axon literature and further extended in order to investigate the effects of ion transport upon the osmotic flux of water into the cell. The model predicts the slow length changes of OHCs reported in the literature a feature which may control the contribution of OHCs to cochlear amplification.