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Periodontal tissue regeneration is the ultimate goal of the treatment for periodontitis-affected teeth. The success of regenerative modalities relies heavily on the utilization of appropriate biomaterials with specific properties. Poly (lactic-co-glycolic acid) (PLGA), a synthetic aliphatic polyester, has been actively investigated for periodontal therapy due to its favorable mechanical properties, tunable degradation rates, and high biocompatibility. Despite the attractive characteristics, certain constraints associated with PLGA, in terms of its hydrophobicity and limited bioactivity, have led to the introduction of modification strategies that aimed to improve the biological performance of the polymer. Here, we summarize the features of the polymer and update views on progress of its applications as barrier membranes, bone grafts, and drug delivery carriers, which indicate that PLGA can be a good candidate material in the field of periodontal regenerative medicine.

Nanoporous metals are a class of novel nanomaterials with potential applications in many fields such as sensing, catalysis, and fuel cells. The present paper is aimed to investigate atomic mechanisms associated with the uniaxial tensile deformation behavior of nanoporous gold. A phase field method is adopted to generate the bicontinuous open-cell porous microstructure of the material. Molecular dynamics simulations then reveal that the uniaxial tensile deformation in such porous materials is accompanied by an accumulation of stacking faults in ligaments along the loading direction and their junctions with neighboring ligaments, as well as the formation of Lomer–Cottrell locks at such junctions. The tensile strain leads to progressive necking and rupture of some ligaments, ultimately resulting in failure of the material. The simulation results also suggest scaling laws for the effective Young's modulus, yield stress, and ultimate strength as functions of the relative mass density and average ligament size in the material.

Electric fields alter adhesive forces between materials. Electroadhesive forces have been utilized in diverse applications ranging from climbing robots, electrostatic levitation to electro-sticky boards. However, the design of electroadhesive devices still largely relies on empirical or "trial-and-error" approaches. In this work, a theoretical model is presented to analyze the electrostatic field between the supporting wall and the electroadhesive device with periodic coplanar electrodes. The air-gap between the surface of electroadhesive device and the dielectric wall is explicitly taken into account in the model to consider its significant impact on electroadhesive forces. On the basis of this model, the electroadhesive force is calculated by using the Maxwell stress tensor. The effects of key design parameters and working environments on the electroadhesion behavior are further investigated. This study not only provides a tool to reveal the underlying mechanisms of electroadhesion but also suggests potential strategies to optimize novel electroadhesive devices for engineering applications.

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The effects of the content and position of shape memory alloy (SMA) wires on the mechanical properties and interlaminar fracture toughness of glassfiber-reinforced epoxy (GF/epoxy) composite laminates are investigated. For this purpose, varying numbers of SMA wires are embedded in GF/epoxy composite laminates in different stacking sequences. The specimens are prepared by vacuum-assisted resin infusion (VARI) processing and are subjected to static tensile and three-point-bending tests. The results show that specimens with two SMA wires in the stacking sequence of [GF 2 /SMA/ GF 1 /SMA/GF 2 ] and four SMA wires in the stacking sequence of [GF 4 /SMA/ GF 2 /SMA/GF 4 ] exhibit optimal performance. The flexural strength of the optimal four-SMA-wire composite is lower than that of the pure GF/epoxy composite by 5.76% on average, and the flexural modulus is improved by 5.19%. Mode-I and II interlaminar fracture toughness tests using the SMA/ GF/epoxy composite laminates in the stacking sequence of [GF 4 /SMA/GF 2 / SMA/GF 4 ] are conducted to evaluate the mechanism responsible for decreasing the mechanical properties. Scanning electron microscopy (SEM) observations reveal that the main damage modes are matrix delamination, interfacial debonding, and fiber pullout.