Graphene nanosheets (GNSs) have been considered as potential conductive additives for electrodes in Li-ion batteries to replace the existing carbon black (CB). Graphene has exceptionally high aspect ratio and excellent electrical conductivity, enabling the formation of extensive conductive networks at a much lower content than CB. This paper reports the beneficial effects of GNSs with a low percolation threshold on electrochemical performance of Li(4)Ti(5)O(12) (LTO) anodes. The experimental results show that the GNSs with a diameter of 46 μm and a thickness of 4.5 nm have a percolation threshold of 1.8 wt%. The prediction based on the interparticle distance concept gives a percolation threshold of 0.54 wt% for GNSs, which is almost an order of magnitude lower than that for CB particles. The substantially low percolation along with a high electrical conductivity of GNSs explains why the LTO anodes containing only 5 wt% GNSs deliver a much better rate capability than those with 15 wt% CB. However, a higher GNS content of 10 wt% results in re-stacking GNSs, deteriorating the diffusion of Li ions through the thickness of GNSs. The parametric study indicates that the percolation threshold of GNSs is inversely proportional to the aspect ratio of GNSs.

A facile strategy is developed based on a sol-gel method to prepare lithium titanate (Li 4 Ti 5 O 12 , LTO)carbon nanofiber (CNF) composites as anode in Li-ion batteries (LIBs). Depending on the conductive CNF and carbon black (CB) additive contents added in the electrode, the resultant composite particles present either an urchin-like or a corn-dog structure with largely different electronic conductivities and associated electrochemical properties. When small amounts of both one-dimensional CNF and zerodimensional CB particles, 5.0 wt% each, are present, conductive networks are established within the urchin-like LTO secondary particles by the penetrating multiple CNFs, whereas the CB particles attached onto the surface of the LTO particles connect the gaps between them, being able to form extensive three-dimensional conductive networks across the whole composites. The electrodes made from this composite deliver a remarkable capacity of 123 mA h g À1 when charged/discharged at 15 C, which is much higher than 91 mA h g À1 for those made from the neat LTO powders, a reflection of significant improvements in both the conductivity and Li ion diffusion coefficient in the composite electrode. When the CNF content is increased to 10 wt%, corn-dog shaped composites are formed consisting of individual CNFs penetrating the elongated LTO secondary particles along the axial direction with limited conductive networks. The electrodes made from this composite present much poorer capacities at all current rates than those with an urchin-like structure. These intriguing observations verify that both the structure of the active material and the conductivity of the electrode play important roles in delivering high capacities and rate capabilities.

bStreptococcus pneumoniae is a Gram-positive and human-restricted pathogen colonizing the nasopharynx with an absence of clinical symptoms as well as a major pathogen causing otitis media (OM), one of the most common childhood infections. Upon bacterial infection, neutrophils are rapidly activated and recruited to the infected site, acting as the frontline defender against emerging microbial pathogens via different ways. Evidence shows that interleukin 17A (IL-17A), a neutrophil-inducing factor, plays important roles in the immune responses in several diseases. However, its function in response to S. pneumoniae OM remains unclear. In this study, the function of IL-17A in response to S. pneumoniae OM was examined using an in vivo model. We developed a model of acute OM (AOM) in C57BL/6 mice and found that neutrophils were the dominant immune cells that infiltrated to the middle ear cavity (MEC) and contributed to bacterial clearance. Using IL-17A knockout (KO) mice, we found that IL-17A boosted neutrophil recruitment to the MEC and afterwards induced apoptosis, which was identified to be conducive to bacterial clearance. In addition, our observation suggested that the p38 mitogen-activated protein kinase (MAPK) signaling pathway was involved in the recruitment and apoptosis of neutrophils mediated by IL-17A. These data support the conclusion that IL-17A contributes to the host immune response against S. pneumoniae by promoting neutrophil recruitment and apoptosis through the p38 MAPK signaling pathway.