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he flexoelectric energy harvesters face such challenges as the monotonous energy harvesting mode, the low electromechanical coupling coefficient, the only prominent effect on microscales, and the limited energy conversion efficiency on macroscales. The electret, as a dielectric material with embedded charges, exhibits significant flexoelectric-like responses induced by non-uniform deformation. The crumpled film in complex bidirectional contraction, provides a novel efficient energy harvesting approach due to high strain gradients on macroscales. Herein the strong macroscopic electromechanical coupling properties of electrets were combined with the advantageous high strain gradients of crumpling, to establish a deformation theory for crumpled flexoelectret films. Based on this model, the flexoelectric-like responses and energy harvesting characteristics of crumpled flexoelectret films were analyzed for different charge densities, supporting cup radii, film thicknesses, and scales. The results indicate that, for a 1 mm thick flexoelectret film, the effective flexoelectric-like intensity is 2 orders higher than that of the intrinsic flexoelectric effect of the pure PDMS film, with the charge density q=-0.2 mC·m-2. [ABSTRACT FROM AUTHOR]

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Copyright of China Tropical Medicine is the property of China Tropical Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Recently, decellularized dermal matrix hydrogel has broad application prospects in tissue filling and repair because of its injectable and filling irregular space. Cytocompatibility and biocompatibility are the key to tissue repair. It is significant to explore the compatibility of decellularized dermal matrix hydrogel. OBJECTIVE: To construct a decellularized dermal matrix hydrogel scaffold for tissue filling and repair. METHODS: An injectable decellularized dermal matrix hydrogel was prepared, and its microscopic morphology was observed under a scanning electron microscope. The decellularized dermal matrix hydrogels with a concentration of 8 and 10 g/L were co-cultured with bone marrow mesenchymal stem cells, separately, and the cell proliferation and cytocompatibility were tested. The decellularized dermal matrix hydrogels with a protein concentration of 0.25 and 0.5 g/L were injected into different subcutaneous parts of the back of the same SD rat separately, and the degradation of the hydrogels was observed 2 and 4 weeks after the operation. Decellularized dermal matrix hydrogels with protein concentrations of 1, 1.5, and 2 g/L were injected into different subcutaneous parts of the back of the same SD rat separately. At 8 and 16 weeks after the operation, the degradation of the hydrogel was observed and histological analysis was performed. RESULTS AND CONCLUSION: (1) Scanning electron microscopy analysis showed that the decellularized dermal matrix hydrogel exhibited an irregular and randomly oriented porous fibrous structure with different pore sizes. (2) After 1, 3, and 5 days of co-culture, the hydrogels with the two concentrations had no effect on the proliferation of bone marrow mesenchymal stem cells. Live/Dead staining after 1, 2, and 3 days of co-culture showed that the hydrogels with the two concentrations had no effect on the proliferation of bone marrow mesenchymal stem cells, but the cell morphology on the hydrogel changed to some extent. (3) The hydrogel with a protein concentration of 0.25 g/L was degraded after subcutaneous injection for 2 weeks; the hydrogel with a protein concentration of 0.5 g/L was degraded after subcutaneous injection for 4 weeks; the hydrogels with a protein concentration of 1, 1.5, and 2 g/L did not degrade after subcutaneous injection for 16 weeks, and possibly even longer. Hematoxylin-eosin staining showed that after subcutaneous injection for 8 weeks, the hydrogel tissue of the three protein mass concentrations was relatively dense, with a small amount of inflammatory infiltration, and the 2 g/L group had microangiogenesis. After 16 weeks, the hydrogel tissue became loose, and the 1 g/L group was more obvious, and the inflammatory infiltration was alleviated. Immunohistochemical staining showed that the number of microvessels in the hydrogel increased with the increase of injection time. The number of microvessels in the hydrogel increased with the increase of protein concentration. (4) The results confirmed that the injectable decellularized dermal matrix hydrogel had good cytocompatibility and biocompatibility. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Taiwanese Journal of Agricultural Chemistry & Food Science is the property of Agricultural Chemical Society of Taiwan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Taiwanese Journal of Agricultural Chemistry & Food Science is the property of Agricultural Chemical Society of Taiwan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)