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Self-monitoring materials have promising applications in structural health monitoring. However, developing organic afterglow materials for self-monitoring is a highly intriguing yet challenging task. Herein, we design two organic molecules with a twisted donor-acceptor-acceptor' configuration and achieve dual-emissive afterglow with tunable lifetimes (86.1-287.7 ms) by doping into various matrices. Based on a photosensitive resin, a series of complex structures are prepared using 3D printing technology. They exhibit tunable afterglow lifetime and Young's Modulus by manipulating the photocuring time and humidity level. With sufficient photocuring or in dry conditions, a long-lived bright green afterglow without apparent deformation under external loading is realized. We demonstrate that the mechanical properties of complex 3D printing structures can be well monitored by controlling the photocuring time and humidity, and quantitively manifested by afterglow lifetimes. This work casts opportunities for constructing flexible 3D printing devices that can achieve sensing and real-time mechanical detection.
RESUMEN
The specific stacking mode of D/A blocks is often considered to largely determine the physicochemical properties of cocrystals. However, this rule may fail when encountering a large degree of (integer or near-integer) charge transfer situations. Herein, we explore the extensive correlations between the possible smallest structural units, stacking modes, and near-infrared photothermal conversion (NIR-PTC) properties of F4TCNQ-based cocrystals with typical features of integer-charge-transfer. Surprisingly, these cocrystals with distinct stacking modes display analogous D-A interactions, broad red-shift absorption, ultrafast (1-3 ps) relaxation dynamics of excited states, and excellent NIR-PTC properties. This supports that the resulting "D+A-" ion pairs from integer-charge-transfer may serve as the primary structural units beneath the secondary stacking modes to dominate the property of cocrystals. The stacking modes play an important but only secondary role. This work provides new insights into the structure-dynamics-property correlations and modular design of organic cocrystals for PTC and other applications.
RESUMEN
OBJECTIVES: Temporomandibular joint osteoarthritis (TMJOA) is a degenerative disease affecting the joint, which is characterized by injury to the articular cartilage, as well as changes in the synovial and subchondral bone. TMJOA has a high incidence rate, without any effective treatment. Despite the therapeutic potential of mesenchymal stem cells (MSCs) in various diseases, their efficacy in treating TMJOA is constrained by the local hypoxic conditions and elevated reactive oxygen species (ROS) environment within the damaged temporomandibular joint. In recent years, many studies have reported that parathyroid hormone (PTH) can effectively treat TMJOA, and has an important impact on MSC differentiation. Therefore, we hypothesized that PTH may influence the potential of MSCs, thereby improving their therapeutic effect on TMJOA. METHODS: First, we isolated and cultured rat bone marrow MSCs, and evaluated their proliferation and differentiation after adding PTH. Next, the in vitro environment of hypoxia and high ROS was established by hypoxia condition and H2O2 treatment, and the resistance of PTH-treated MSCs to hypoxia and ROS was subsequently investigated. Finally, PTH-treated MSCs were used to treat TMJOA in a rat model to evaluate the efficacy of PTH. RESULTS: PTH enhanced the proliferation ability of MSCs, promoted the osteogenic differentiation of MSCs, and improved the tolerance of MSCs to hypoxia and ROS. Finally, the therapeutic effect of PTH-treated MSCs on TMJOA was significantly improved. CONCLUSION: PTH enhances the therapeutic effect of MSCs on TMJOA in rats.
RESUMEN
The current work studied the physical modification effects of non-covalent surfactant on the carbon-particle-filled nanocomposite. The selected surfactant named Triton™ X-100 was able to introduce the steric repelling force between the epoxy matrix and carbon fillers with the help of beneficial functional groups, improving their dispersibility and while maintaining the intrinsic conductivity of carbon particles. Subsequent results further demonstrated that the physically modified carbon nanotubes, together with graphene nanoplates, constructed an effective particulate network within the epoxy matrix, which simultaneously provided mechanical reinforcement and conductive improvement to the hybrid nanocomposite system. For example, the hybrid nanocomposite showed maximum enhancements of ~75.1% and ~82.5% for the quasi-static mode-I critical-stress-intensity factor and dynamic compressive strength, respectively, as compared to the neat epoxy counterpart. Additionally, the fine dispersion of modified fillers as a double-edged sword adversely influenced the electrical conductivity of the hybrid nanocomposite because of the decreased contact probability among particles. Even so, by adjusting the modified filler ratio, the conductivity of the hybrid nanocomposite went up to the maximum level of ~10-1-100 S/cm, endowing itself with excellent electro-thermal behavior.
RESUMEN
BACKGROUND: Mandibular fracture healing is a complex process involving nerves and growth factors. Nerve growth factor (NGF) not only facilitates the maintenance of sympathetic neurite growth but also stimulates other growth factors that can promote the essential osteogenesis and angiogenesis for fracture healing. Therefore, it is necessary to analyze the combined effects of NGF, bone morphogenic protein-9 (BMP-9), and vascular endothelial growth factor (VEGF) to accelerate the healing of mandible fractures. METHODS: The models of mandible fracture with local nerve injury established in 48 rabbits were randomly divided into nerve growth factor group (NGF group), gelatin sponge group (GS group), blank group, and intact group. The recovery of nerve reflex was assessed by observing the number of rabbits with lower lip responses to acupuncture. The fracture healing was observed with visual and CBCT, and then callus tissues from the mandibular fracture area were collected for hematoxylin and eosin (HE) staining observation, and the expression of BMP-9 and VEGF in callus at different stages was detected by quantitative real-time PCR (qRT-PCR). RESULTS: Needling reaction in the lower lip showed the number of animals with nerve reflex recovery was significantly higher in the NGF group than that in the GS and blank groups at the 2nd and 4th weeks after the operation. The combined results of macroscopic observation, CBCT examination, and histological analysis showed that a large number of osteoblasts and some vascular endothelial cells were found around the trabecular bone in the NGF group and the amount of callus formation and reconstruction was better than that in the GS group at the 2nd week after the operation. The qRT-PCR results indicated that the expression levels of BMP-9 and VEGF in the four groups reached the highest values at the 2nd week, while the expression levels of both in the NGF group were significantly higher than that in the GS group. CONCLUSION: The exogenous NGF could accelerate the healing of mandible fractures. This work will provide a new foundation and theoretical basis for clarifying the mechanism of fracture healing, thereby promoting fracture healing and reducing the disability rate of patients.
