Nanopores have become a model system to understand transport properties at the nanoscale. We report experiments and modeling of ionic current in aprotic solvents with different dipole moments through conically shaped nanopores in a polycarbonate film and through glass nanopipettes. We focus on solutions of the salt LiClO4, which is of great importance in modeling lithium based batteries. Results presented suggest ion current rectification observed results from two effects: (i) adsorption of Li(+) ions to the pore walls, and (ii) a finite dipole moment rendered by adsorbed solvent molecules. Properties of surfaces in various solvents were probed by means of scanning ion conductance microscopy, which confirmed existence of an effectively positive surface potential in aprotic solvents with high dipole moments.

Abstract-Pressure ulcers (PUs) in individuals with spinal cord injury (SCI) present a persistent and costly problem. Continuing effort in developing new technologies that support selfmanaged care is an important prevention strategy. Specifically, the aims of this scoping review are to review the key concepts and factors related to self-managed prevention of PUs in individuals with SCI and appraise the technologies available to assist patients in self-management of PU prevention practices. There is broad consensus that sustaining long-term adherence to prevention regimens is a major concern. Recent literature highlights the interactions between behavioral and physiological risk factors. We identify four technology categories that support self-management: computer-based educational technologies demonstrated improved short-term gains in knowledge (2 studies), interface pressure mapping technologies demonstrated improved adherence to pressure-relief schedules up to 3 mo (5 studies), electrical stimulation confirmed improvements in tissue tolerance after 8 wk of training (3 studies), and telemedicine programs demonstrated improvements in independence and reduced hospital visits over 6 mo (2 studies). Overall, self-management technologies demonstrated low-to-moderate effectiveness in addressing a subset of risk factors. However, the effectiveness of technologies in preventing PUs is limited due to a lack of incidence reporting. In light of the key findings, we recommend developing integrated technologies that address multiple risk factors.

Hydrophobic nanopores provide a model system to study hydrophobic interactions at the nanoscale. Such nanopores could also function as a valve since they halt the transport of water and all dissolved species. It has recently been found that a hydrophobic pore can become wetted i.e. filled with condensed water or an aqueous solution of salt when a sufficiently high electric field is applied across the membrane. The wetting process is reversible thus when the voltage is lowered or switched off, the pore comes back to a closed state due to water evaporation in the pore. In this manuscript we present experimental studies on how the switching between conducting and non-conducting states can be regulated by the electrolyte concentration. Transport properties of single nanopores modified with alkyl chains of different lengths were recorded in salt concentrations between 10 mM and 1 M KCl. Nanopores modified with propyl chains exhibited gating in 10 mM KCl and were open for ionic transport for all voltages at higher salt concentrations. Nanopores modified with decyl chains did not conduct current in 10 mM and exhibited repeatable hydrophobic gating in 100 mM and 1 M KCl. The results are explained in the context of Maxwell stress in confined geometry with local surface charges, which change the shape of the water-vapor interface and promote wetting.