41 research outputs found
Spacers to improve performance and porosity of graphene based polymer electrolyte fuel cells
Graphene has been suggested as a potential support material to replace commercial carbon black due to its carbon corrosion resistance. However, graphene-based electrodes typically perform poorly in MEA testing due to restacking of the graphitic sheets. In this study we investigate the introduction of carbon black and their effects on the porosity and current density of graphene-based supports
The K+ Channel Opener 1-EBIO Potentiates Residual Function of Mutant CFTR in Rectal Biopsies from Cystic Fibrosis Patients
BACKGROUND: The identification of strategies to improve mutant CFTR function remains a key priority in the development of new treatments for cystic fibrosis (CF). Previous studies demonstrated that the Kâș channel opener 1-ethyl-2-benzimidazolone (1-EBIO) potentiates CFTR-mediated Clâ» secretion in cultured cells and mouse colon. However, the effects of 1-EBIO on wild-type and mutant CFTR function in native human colonic tissues remain unknown. METHODS: We studied the effects of 1-EBIO on CFTR-mediated Clâ» secretion in rectal biopsies from 47 CF patients carrying a wide spectrum of CFTR mutations and 57 age-matched controls. Rectal tissues were mounted in perfused micro-Ussing chambers and the effects of 1-EBIO were compared in control tissues, CF tissues expressing residual CFTR function and CF tissues with no detectable Clâ» secretion. RESULTS: Studies in control tissues demonstrate that 1-EBIO activated CFTR-mediated Clâ» secretion in the absence of cAMP-mediated stimulation and potentiated cAMP-induced Clâ» secretion by 39.2±6.7% (P<0.001) via activation of basolateral CaÂČâș-activated and clotrimazole-sensitive KCNN4 Kâș channels. In CF specimens, 1-EBIO potentiated cAMP-induced Clâ» secretion in tissues with residual CFTR function by 44.4±11.5% (P<0.001), but had no effect on tissues lacking CFTR-mediated Clâ» conductance. CONCLUSIONS: We conclude that 1-EBIO potentiates Clâ»secretion in native CF tissues expressing CFTR mutants with residual Clâ» channel function by activation of basolateral KCNN4 Kâș channels that increase the driving force for luminal Clâ» exit. This mechanism may augment effects of CFTR correctors and potentiators that increase the number and/or activity of mutant CFTR channels at the cell surface and suggests KCNN4 as a therapeutic target for CF
Scalable sacrificial templating to increase porosity and platinum utilisation in graphene-based polymer electrolyte fuel cell electrodes
Polymer electrolyte fuel cells hold great promise for a range of applications but require advances in durability for widespread commercial uptake. Corrosion of the carbon support is one of the main degradation pathways; hence, corrosion-resilient graphene has been widely suggested as an alternative to traditional carbon black. However, the performance of bulk graphene-based electrodes is typically lower than that of commercial carbon black due to their stacking effects. This article reports a simple, scalable and non-destructive method through which the pore structure and platinum utilisation of graphene-based membrane electrode assemblies can be significantly improved. Urea is incorporated into the catalyst ink before deposition, and is then simply removed from the catalyst layer after spraying by submerging the electrode in water. This additive hinders graphene restacking and increases porosity, resulting in a significant increase in Pt utilisation and current density. This technique does not require harsh template etching and it represents a pathway to significantly improve graphene-based electrodes by introducing hierarchical porosity using scalable liquid processes