Yaru Yang

Engineering three-dimensional (3D) microstructures in sensing layers is an effective strategy for improving the performance of flexible pressure sensors. However, most technologies for constructing 3D microstructures involve complex fabrication procedures and high costs, which hinder the commercialization of flexible electronics. Herein, inspired by embossing in papermaking, we developed a flexible piezoresistive pressure sensor based on carbonized embossed paper (CEP). Embossing followed by carbonization produced a hierarchical structure comprising a porous fibrous network and an array of surface micro-bumps. The spatial frequency and geometry of the micro-bump array were adjusted using metal mesh molds with different mesh counts. The CEP-50 sensor exhibited a sensitivity of 70.14 kPa⁻¹ over 0–0.2 kPa, a working range of 0–150 kPa, a response time of approximately 60 ms, and stable responses over 5000 loading–unloading cycles. The CEP-50 sensor exhibited a sensitivity of 70.14 kPa⁻¹ over 0–0.2 kPa, a working range of 0–150 kPa, a response time of approximately 60 ms, a low detection limit of 1.5 Pa, and stable responses over 5000 loading–unloading cycles. An equivalent circuit and finite element analysis were used to develop a qualitative interpretation of the pressure-dependent electrical response. The sensor was further demonstrated for monitoring pulse, respiration, phonation, and body movements. This embossing-based fabrication approach provides a practical route for developing paper-based wearable pressure sensors.

Introduction: To address the dilemma that the small sample size of hospital energy consumption data makes it difficult to predict short-term electricity consumption, a combination of the Firefly Optimization Algorithm (FOA) and the Support Vector Regression (SVR) algorithm, i.e., FOA-SVR, was proposed in this work.Methods: By combining standardized sample data with the FOA to optimize the hyperparameters of the SVR model, the proposed approach enhances the model’s ability to capture the variation characteristics of hospital electricity consumption.Results: The FOA-SVR hybrid strategy achieves an optimal balance between prediction accuracy and computational efficiency when the number of fireflies was 30. The prediction accuracy indicator (Coefficient of Determination, R²) was 0.855, respectively. Under these conditions, the hybrid strategy has the dual advantage of running faster than the existing Sparrow search algorithm, and the traditional seagull optimization algorithm, with run times reduced by 21.192 s and 14.612 s, respectively. When the length of electricity consumption data was greater than or equal to 36, R² of the FOA-SVR hybrid strategy was higher than 0.849.Discussion: The FOA-SVR hybrid strategy realizes a kind of efficient prediction of power consumption in medical office buildings with a small sample data volume, which provides theoretical and data support for the reasonable optimization of hospital energy use structure and has practical significance for the intelligence of hospital energy management.

In this work, KH550 (γ-aminopropyl triethoxy silane)-modified hexagonal boron nitride (BN) nanofillers were synthesized through a one-step ball-milling route. Results show that the KH550-modified BN nanofillers synthesized by one-step ball-milling (BM@KH550-BN) exhibit excellent dispersion stability and a high yield of BN nanosheets. Using BM@KH550-BN as fillers for epoxy resin, the thermal conductivity of epoxy nanocomposites increased by 195.7% at 10 wt%, compared to neat epoxy resin. Simultaneously, the storage modulus and glass transition temperature (Tg) of the BM@KH550-BN/epoxy nanocomposite at 10 wt% also increased by 35.6% and 12.4 °C, respectively. The data calculated from the dynamical mechanical analysis show that the BM@KH550-BN nanofillers have a better filler effectiveness and a higher volume fraction of constrained region. The morphology of the fracture surface of the epoxy nanocomposites indicate that the BM@KH550-BN presents a uniform distribution in the epoxy matrix even at 10 wt%. This work guides the convenient preparation of high thermally conductive BN nanofillers, presenting a great application potential in the field of thermally conductive epoxy nanocomposites, which will promote the development of electronic packaging materials.

Implants are essential therapeutic tools for treating bone fractures and joint replacements. Despite the in-depth study of osseointegration for more than fifty years, poor osseointegration caused by aseptic loosening remains one of the leading causes of late implant failures. Osseointegration is a highly sophisticated and spatiotemporal process in vivo involving the immune response, angiogenesis, and osteogenesis. It has been unraveled that the nervous system plays a pivotal role in skeletal health via manipulating neurotrophins, neuropeptides, and nerve cells. Herein, the research related to nervous system-driven osseointegration was systematically analyzed and reviewed, aiming to demonstrate the prominent role of neuromodulation in osseointegration. Additionally, it is indicated that the implant design considering the role of neuromodulation might be a promising way to prevent aseptic loosening.

Osteocytes function as the master orchestrator of bone remodeling activity in the telophase of osseointegration. However, most contemporary studies focus on the manipulation of osteoblast and/or osteoclast functionality via implant surface engineering, which neglects the pivotal role of osteocytes in de novo bone formation. It is confirmative that osteocyte processes extend directly to the implant surface, but whether the surface physicochemical properties can affect the functionality of osteocytes and determine the fate of the osseointegration in the final remodeling stage remains to be determined. Titania nanotube arrays (NTAs) with distinct diameters were fabricated to investigate the relationship between the nanoscale topography and the functionality of osteocytes. In vitro results pinpointed that NTA with a diameter of 15 nm (NTA-15) significantly promote osteogenesis of osteocytes via the enhancement of spreading, proliferation, and mineralization. The osteocyte transcriptome of each group further revealed that the TGF-β signaling pathway plays a pivotal role in osteocyte-mediated osteogenesis. The in vivo study definitely mirrored the aforementioned results, that NTA-15 significantly promotes bone formation around the implant. Consequently, nanoscaled topography-induced osteocyte functionality is important in late osseointegration. This suggests that surface designs targeting osteocytes may, therefore, be a potential approach to solving the aseptic loosening of the implant, and thus strengthen osseointegration.

To improve the flame retardant properties of polyethylene terephthalate (PET), glucose-derived carbon nanospheres (CNSs) were synthesized and introduced into PET matrix. The thermal property and flame retardancy of CNSs/PET composites were thoroughly investigated. Results showed that CNSs displayed good flame-retardant performance for PET. When blended with only 1.0 wt.% of CNSs, CNSs/PET exhibited a limiting oxygen index (LOI) of 26.3 and a vertical combustion class of V-2, and its peak-heat release rate (pk-HRR) was reduced by 41.6%. Importantly, the initial decomposition temperature and the maximum weight loss temperature of CNSs/PET were 52°C and 199°C higher than those of PET, respectively. Furthermore, a condensed phase flame-retardant mechanism appeared in CNSs/PET, which formed a dense and thermally stable protective char layer during combustion. Overall, this study disclosed the flame-retardant potential and possible mechanism of CNSs for polyesters, which would benefit the development of carbon-based materials and flame-retardant polymers.

The micromorphology of fillers plays an important role in tribological and mechanical properties of polymer matrices. In this work, a TiO₂-decorated Ti₂C₃ (TiO₂/Ti₃C₂) composite particle with unique micro-nano morphology was engineered to improve the tribological and thermo-mechanical properties of epoxy resin. The TiO₂/Ti₃C₂ were synthesized by hydrothermal growth of TiO₂ nanodots onto the surface of accordion-like Ti₃C₂ microparticles, and three different decoration degrees (low, medium, high density) of TiO₂/Ti₃C₂ were prepared by regulating the concentration of TiO₂ precursor solution. Tribological test results indicated that the incorporation of TiO₂/Ti₃C₂ can effectively improve the wear rate of epoxy resin. Among them, the medium density TiO₂/Ti₃C₂/epoxy nanocomposites gained a minimum wear rate. This may be ascribed by the moderate TiO₂ nanodot protuberances on the Ti₃C₂ surface induced a strong mechanical interlock effect between medium-density TiO₂/Ti₃C₂ and the epoxy matrix, which can bear a higher normal shear stress during sliding friction. The morphologies of worn surfaces and wear debris revealed that the wear form was gradually transformed from fatigue wear in neat epoxy to abrasive wear in TiO₂/Ti₃C₂/epoxy nanocomposites. Moreover, the results of thermo-mechanical property indicated that incorporation of TiO₂/Ti₃C₂ also effectively improved the storage modulus and glass transition temperature of epoxy resin.