Mitigating Bubble Traffic in Gas-Evolving Electrodes via Spinodally Derived Architectures.

Porous electrodes are widely used in the industry because of their high surface area to volume ratio. However, the stochastic morphology of most commercially available porous electrodes results in poor electrical connections in the solid phase and inefficient mass transport through the pore phase. This can be especially detrimental for gas-evolving processes such as water electrolysis for hydrogen and oxygen generation. Bicontinuous interfacially jammed emulsion gels (bijels) offer templates from which to create porous electrodes with robust solid-state interconnectivity and a uniform pore structure that facilitate improved electron and mass transport. In this study, gas release rates and electrochemical experiments are utilized to study the effects of powder- and bijel-derived microstructures on hydrogen generation by water electrolysis. The bijel-derived electrodes are shown to expel product gas faster and require up to 25% less overpotential to drive water electrolysis over the range of current densities tested (-5 to -40 mA/cm2) than their powder-derived analogs. Our findings suggest that the uniform and bicontinuous domains of bijel-derived porous electrodes can mitigate the limited current distribution and deleterious bubble effect found in stochastic electrodes, in turn improving the overall performance of electrolytic processes requiring transport of gaseous species.

Scalable synthesis of gyroid-inspired freestanding three-dimensional graphene architectures.

Three-dimensional porous architectures of graphene are desirable for energy storage, catalysis, and sensing applications. Yet it has proven challenging to devise scalable methods capable of producing co-continuous architectures and well-defined, uniform pore and ligament sizes at length scales relevant to applications. This is further complicated by processing temperatures necessary for high quality graphene. Here, bicontinuous interfacially jammed emulsion gels (bijels) are formed and processed into sacrificial porous Ni scaffolds for chemical vapor deposition to produce freestanding three-dimensional turbostratic graphene (bi-3DG) monoliths with high specific surface area. Scanning electron microscopy (SEM) images show that the bi-3DG monoliths inherit the unique microstructural characteristics of their bijel parents. Processing of the Ni templates strongly influences the resultant bi-3DG structures, enabling the formation of stacked graphene flakes or fewer-layer continuous films. Despite the multilayer nature, Raman spectra exhibit no discernable defect peak and large relative intensity for the Raman 2D mode, which is a characteristic of turbostratic graphene. Moiré patterns, observed in scanning tunneling microscopy images, further confirm the presence of turbostratic graphene. Nanoindentation of macroscopic pillars reveals a Young's modulus of 30 MPa, one of the highest recorded for sp2 carbon in a porous structure. Overall, this work highlights the utility of a scalable self-assembly method towards porous high quality graphene constructs with tunable, uniform, and co-continuous microstructure.

Myasthenia Gravis in Pregnancy.

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease and is the most common disorder of neuromuscular transmission. MG is caused by a defect in the transmission of nerve impulses to muscles in which communication from nerves to muscles is interrupted at the neuromuscular junction. This interruption can cause significant impact to muscle functions, which can have serious consequences for a pregnant woman, especially during labor. This brief article, which is meant to be used as an easy-reference tool in the clinical setting, examines the disease process and its effect on the antepartum, intrapartum and postpartum periods.