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In this paper, polystyrene (PS)-based reduced graphene oxide (rGO) composites were prepared by mixing PS latex particles with graphene oxide (GO) and the following in-situ reduction. The structure and morphology of PS/rGO composites were characterized, and the effects of rGO content on the dielectric properties as well as thermal stability of PS/rGO composites were investigated. Results showed that rGO sheets armoured on the surface of PS particles and exhibited well dispersion in the PS matrix after hot compression. The introduction of rGO improved the dielectric properties of the composites remarkably. When rGO content was 0.12 vol%, the dielectric permittivity and breakdown strength of PS/rGO arrived at 6.3 at102 Hz and 107 kV/mm, with 50% and 35.4% enhancement compared to the pristine PS. Furthermore, PS/rGO presented better thermal stability than the pristine PS, but the overlapping of rGO sheets in PS matrix induced the instability of dielectric loss with frequency. [ABSTRACT FROM AUTHOR]

Background: Treatment of muscle belly lacerations remains a problem for surgeons. Inadequate repair of lacerations can cause functional disability. To date, there is no consensus on the method of repair for these injuries. We have previously described a technique of repairing mid-substance muscle belly lacerations. The aim of this study was to determine the ultimate strength of an intact muscle belly and to compare the anchor suture (AS) technique with the modified Kessler (MK) technique. Methods: Fifteen fresh frozen hind-legs from adolescent pigs were divided into three groups and used for the testing. Each group consisted of five specimens. Group one was the intact control group, group two was repaired with the MK technique and group three was repaired with the AS technique. Following repair, the muscles were secured in a custom-made fixation apparatus and underwent linear tensioning at a rate of 25 mm/min, generating a load-displacement curve for each specimen. The data regarding ultimate strength, modes of failure and number of intact suture/anchor constructs (for groups 2 and 3) was calculated. Results: The ultimate strength of the intact muscle group of was found to be 608.1 ± 107.9  N. This was significantly (p < 0.05) higher than the pull-out strength of the MK and AS groups. The pull-out strength of the AS group was 143.1 ± 36.7 N, nearly twice that of the MK group 69.8 ± 16.4 N (p = 0.11). Suture pull-out was the most common mode of failure. Conclusions: The AS technique was found to have both higher strain and nearly twice the ultimate pull-out strength compared to the MK repair group. We suggest the AS technique as a viable technique for mid-substance muscle belly repairs. [ABSTRACT FROM AUTHOR]

Polymer‐based dielectric composites with simultaneously improved dielectric constant and breakdown strength have great potential applications in energy storage. In this paper, polyaniline@BaTiO3 (PANI@BT) nanoparticles with core‐shell structure are first fabricated by in‐situ chemical oxidative polymerization, and deposited on the surface of two‐dimensional nanoplatelets (graphene oxide [GO] and hexagonal boron nitride nanosheets [BNNS]), which are then utilized to prepare poly(vinylidene fluoride) (PVDF)‐based composites. The presence of 2D nanoplatelets is found to significantly ameliorate the dispersion of PANI@BT particles in the PVDF matrix, and thus endowing the resultant PVDF composites with improved comprehensive performance. The dielectric constant of PANI@BT‐GO/PVDF and PANI@BT‐BNNS/PVDF composites with 50 wt% fillers increase to 124.9 and 169.5 at 100 Hz, accompanied with relatively low dielectric loss. When the filler content is 10 wt%, the breakdown strength of PANI@BT‐BNNS/PVDF achieves 133.5 kV/mm, which is 9.7% and 71.8% higher than that of the pristine PVDF and PANI@BT/PVDF composites. Meanwhile, the tensile stress also reaches the highest value of 43.38 MPa. In addition, the PANI@BT‐GO/PVDF and PANI@BT‐BNNS/PVDF composites present higher thermal decomposition temperature in comparison with PANI@BT/PVDF composites. [ABSTRACT FROM AUTHOR]