Size and Temperature Effects on Band Gap Analysis of a Defective Phononic Crystal Beam

In this paper, a new defective phononic crystal (PC) microbeam model in a thermal environment is developed with the application of modified couple stress theory (MCST). By using Hamilton’s principle, the wave equation and complete boundary conditions of a heated Bernoulli–Euler microbeam are obtained. The band structures of the perfect and defective heated PC microbeams are solved by employing the transfer matrix method and supercell technology. The accuracy of the new model is validated using the finite element model, and the parametric analysis is conducted to examine the influences of size and temperature effects, as well as defect segment length, on the band structures of current microbeams. The results indicate that the size effect induces microstructure hardening, while the increase in temperature has a softening impact, decreasing the band gap frequencies. The inclusion of defect cells leads to the localization of elastic waves. These findings have significant implications for the design of microdevices, including applications in micro-energy harvesters, energy absorbers, and micro-electro-mechanical systems (MEMS)

Effects of the Pathogenic Mutation A117V and the Protective Mutation H111S on the Folding and Aggregation of PrP106-126: Insights from Replica Exchange Molecular Dynamics Simulations.

The fragment 106-126 of prion protein exhibits similar properties to full-length prion. Experiments have shown that the A117V mutation enhances the aggregation of PrP106-126, while the H111S mutation abolishes the assembly. However, the mechanism of the change in the aggregation behavior of PrP106-126 upon the two mutations is not fully understood. In this study, replica exchange molecular dynamics simulations were performed to investigate the conformational ensemble of the WT PrP106-126 and its two mutants A117V and H111S. The obtained results indicate that the three species are all intrinsically disordered but they have distinct morphological differences. The A117V mutant has a higher propensity to form β-hairpin structures than the WT, while the H111S mutant has a higher population of helical structures. Furthermore, the A117V mutation increases the hydrophobic solvent accessible surface areas of PrP106-126 and the H111S mutation reduces the exposure of hydrophobic residues. It can be concluded that the difference in populations of β-hairpin structures and the change of hydrophobic solvent accessible areas may induce the different aggregation behaviors of the A117V and the H111S mutated PrP106-126. Understanding why the two mutations have contrary effects on the aggregation of PrP106-126 is very meaningful for further elucidation of the mechanism underlying aggregation and design of inhibitor against aggregation process

Eco-design for recycled products: Rejuvenating mullite from coal fly ash

Secondary pollution exists extensively in the utilization of industrial solid waste. To reduce environmental risks of building material products recycled from industrial solid waste, a framework of eco-design strategy is established based on the existing eco-design method and life cycle thinking. It focuses on controlling of chemical components by integrating tracking and controlling of toxic components introduced by industrial solid waste. The framework consists of four steps: analysis of raw material applicability, analysis of process control conditions, and safety analysis during product use and final disposal. Raw material requirements are designed including effective components, quality disturbance components, and environmental risk components. Operating condition requirements are given to control flows of selected components in key procedures. Environmental safety of products during use and final disposal under these requirements are tested by simulation experiments. Then a series of eco-design requirements are proposed. The framework is applied in a case study of mullite recycled from coal fly ash and the result shows that the established framework could be feasible for products recycled from industrial solid waste. Nevertheless, the method needs expansion with industrial solid waste properties and product requirements, and steps need optimization if applied in other wastes.</p

The calculated secondary structure probabilities for the WT PrP106-126 and its two mutants A117V, H111S.

<p>The calculated secondary structure probabilities for the WT PrP106-126 and its two mutants A117V, H111S.</p

Distributions of hydrophobic solvent accessible areas of WT PrP106-126 and its two mutants A117V, H111S.

<p>Hydrophobic SASA of residues Val, Met and Leu were considered.</p

The secondary structure propensities of the residues in the studied peptides.

<p>The results were obtained using the time intervals of 40–200 ns.</p

The side chain-side chain contact maps of WT, A117V and H111S in 40-200ns time intervals.

<p>The right column represents substracted contact maps between A117V and WT and between H111S and WT. The (i,i), (i,i±1) and (i,i±2) contacts are not included.</p