Well-ordered mesoporous Fe2O3/C composites as high performance anode materials for sodium-ion batteries.

Sodium-ion batteries have attracted considerable attention in recent years. In order to promote the practical application of sodium-ion batteries, the electrochemical performances, such as specific capacity, reversibility, and rate capability of the anode materials, should be further improved. In this work, a Fe2O3/C composite with a well-ordered mesoporous structure is prepared via a facile co-impregnation method by using mesoporous silica SBA-15 as a hard template. When used as an anode material for sodium-ion batteries, the well-ordered mesoporous structure ensures fast mass transport kinetics. The presence of nano-sized Fe2O3 particles confined within the carbon walls significantly enhances the specific capacity of the composite. The carbon walls in the composite act not only as an active material contributing to the specific capacity, but also as a conductive matrix improving the cycling stability of Fe2O3 nanoparticles. As a result, the well-ordered mesoporous Fe2O3/C composite exhibits high specific capacity, excellent cycleability, and high rate capability. It is proposed that this simple co-impregnation method is applicable for the preparation of well-ordered mesoporous transition oxide/carbon composite electrode materials for high performance sodium-ion and lithium-ion batteries.

Role of electricity production in the anaerobic decolorization of dye mixture by exoelectrogenic bacterium Shewanella oneidensis MR-1.

This study investigated the anaerobic decolorization of the dye mixture containing methyl orange (MO) and naphthol green B (NGB) by Shewanella oneidensis MR-1. S. oneidensis MR-1 showed a strong ability to decolorize the dye mixture. MO was easier to get the electrons and inhibited the reduction of NGB, despite of its lower redox potential than NGB. The Mtr respiratory pathway played an important role in this process. Meantime, addition of extracellular electron shuttles accelerated the decolorization. Those results suggest that the decolorization capacity of S. oneidensis MR-1 is associated with the electricity production. The operating parameters, such as electron acceptors, temperature, and pH, were also investigated in this study. Thus, this work may facilitate a better understanding of the extensive nonspecific reduction capacity of exoelectrogens and is beneficial for promoting their application in bioremediation.

A modified technique for culturing primary fetal rat cortical neurons.

The study explored a modified primary culture system for fetal rat cortical neurons. Day E18 embryos from pregnant Sprague Dawley rats were microdissected under a stereoscope. To minimize enzymatic damage to the cultured neurons, we applied a sequential digestion protocol using papain and Dnase I. The resulting sifted cell suspension was seeded at a density of 50,000 cells per cm(2) onto 0.1 mg/mL L-PLL-covered vessels. After a four-hour incubation in high-glucose Dulbecco's Modified Eagle's Medium (HG-DMEM) to allow the neurons to adhere, the media was changed to neurobasal medium that was refreshed by changing half of the volume after three days followed by a complete medium change every week. The cells displayed progressively robust neurite extension, and nonneuronal-like cells could barely be detected by five days in vitro (DIV); cell growth was still substantial at 14 DIV. Neurons were identified by ß-tubulin III immunofluorescence, and neuronal purity within the cultures was assessed at over 95% by both flow cytometry and by dark-field counting of ß-tubulin III-positive cells. These results suggest that the protocol was successful and that the high purity of neurons in this system could be used as the basis for generating various cell models of neurological disease.

Biodecolorization of Naphthol Green B dye by Shewanella oneidensis MR-1 under anaerobic conditions.

The anaerobic decolorization of metal-complex dye Naphthol Green B (NGB) by a metal-reducing bacterium, Shewanella oneidensis MR-1, was investigated. S. oneidensis MR-1 showed a high capacity for decolorizing NGB even at a concentration of up to 1000mg/L under anaerobic conditions. Maximum decolorization efficiency was appeared at pH 8.0 and 40°C. Addition of iron oxide caused no inhibition to the NGB decolorization, while the presence of ferric citrate, nitrite, or nitrate almost completely terminated the decolorization. Biosynthesis of nanomaterials was observed coupled with the degradation of NGB when thiosulfate was added. The Mtr respiratory pathway was found to be responsible for the decolorization of NGB by S. oneidensis, in which extracellular electron shuttle also plays a positive role in promoting the decolorization.