Search

Coal gangue concrete (CGC), a great low cost and environment‐friendly material, is considered to be the most effective substitute for normal concrete. The bond performance of steel bar embedded in CGC determines the feasibility of using CGC as structure material. So, this study presents an experimental program to investigate the bond strength of steel bar embedded in CGC compared to the one in normal‐aggregate concrete. The experimental program contains 75 specimens that are tested using the pull‐out test. In this study, coal gangue coarse aggregate replacement ratios (0%, 25%, 50%, 75%, and 100%), water–cement ratio (0.50, 0.45, and 0.40), and rebar diameters (14 mm, 16 mm, and 18 mm) were considered to analyze the variation law of bond strength. The test results show that the bond strength increased slightly with the decrease of water–cement ratio. The bond strength decreased slightly with the increase the aggregate replacement ratio if the replacement ratio was less than 50%. In contrast, the bond strength decreased significantly when the aggregate replacement ratio was more than 50%. In addition, the bond strength increases first and then reduces with increasing of bar diameters. Lastly, a new model of predicting the bond strength between the deformed steel bar and coal gangue concrete was proposed in this study because the widely used prediction models for the bond strength were not suitable for the coal gangue concrete. [ABSTRACT FROM AUTHOR]

In cognitive radio networks, the most important goal of spectrum sharing is to benefit both the seller and buyer. In order to increase the total benefits generated in spectrum sharing, this paper introduces a memory mechanism between the spectrum agent and multi-primary service providers (PSPs) and proposes a spectrum trading algorithm based on the mechanism. In this algorithm, all PSPs compete with each other and sell their idle spectrum resource to the agent to maximise their own profits. Then, the agent auctions the spectrum resources obtained in multi-secondary users. Finally, a new auction pricing function is designed to decrease the auction trading prices and increase the benefits of secondary users. Nash equilibrium is considered to be the optimal result. Simulation results show that the proposed algorithm provides 10-15% margin over the conventional algorithm both in the price and spectrum quantity. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The toxic property thus far shared by both ALS-linked SOD1 variants and wild-type SOD1 is an increased propensity to aggregation. However, whether SOD1 oligomers or aggregates are toxic to cells remains to be well defined. Moreover, how the toxic SOD1 species are removed from intra- and extracellular environments also needs to be further explored. The DNA binding has been shown to be capable of accelerating the aggregatio\n of wild-type and oxidized SOD1 forms under acidic and neutral conditions. In this study, we explore the binding of DNA and heparin, two types of essential life polyanions, to A4V, an ALS-linked SOD1 mutant, under acidic conditions, and its consequences. The polyanion binding alters the A4V conformation, neutralizes its local positive charges, and increases its local concentrations along the polyanion chain, which are sufficient to lead to acceleration of the pH-dependent A4V aggregation. The accelerated aggregation, which is ascribed to the polyanion binding-mediated removal or shortening of the lag phase in aggregation, contributes to the formation of amorphous A4V nanoparticles. The prolonged incubation with polyanions not only results in the complete conversion of likely soluble toxic A4V oligomers into non- and low-toxic SDS-resistant aggregates, but also increases their stability. Although this is only an initial step toward reducing the toxicity of SOD1 mutants, the accelerating role of polyanions in protein aggregation might become one of the rapid pathways that remove toxic forms of SOD1 mutants from intra- and extracellular environments. [ABSTRACT FROM AUTHOR]