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AbstractPolyetheretherketone (PEEK) implants have emerged as a clinically favored alternative to titanium alloy implants for cranial bone substitutes due to their excellent mechanical properties and biocompatibility. However, the biological inertness of PEEK has hindered its clinical application. To address this issue, we developed a dual-functional surface modification method aimed at enhancing both osteogenesis and antibacterial activity, which was achieved through the sustained release of chondroitin sulfate (CS) and levofloxacin (LVFX) from a biomimetic polydopamine (PDA) coating on the PEEK surface. CS was introduced to promote cell adhesion and osteogenic differentiation. Meanwhile, incorporation of antibiotic LVFX was essential to prevent infections, which are a critical concern in bone defect repairing. To our delight, experiment results demonstrated that the SPKD/CS-LVFX specimen exhibited enhanced hydrophilicity and sustained drug release profiles. Furthermore, in vitro experiments showed that cell growth and adhesion, cell viability, and osteogenic differentiation of mouse calvaria-derived osteoblast precursor (MC3T3-E1) cells were significantly improved on the SPKD/CS-LVFX coating. Antibacterial assays also confirmed that the SPKD/CS-LVFX specimen effectively inhibited the growth of Escherichia coli and Staphylococcus aureus, attributable to the antibiotic LVFX released from the PDA coating. To sum up, this dual-functional PEEK implant showed a promising potential for clinical application in bone defects repairing, providing excellent osteogenic and antibacterial properties through a synergistic approach. [ABSTRACT FROM AUTHOR]

Detecting temperature and concentration fields within engine combustors holds paramount significance in enhancing combustion efficiency and ensuring operational safety. Within the realm of engine combustors, the laminar absorption spectroscopy technique has garnered considerable attention. Particularly crucial is the optimization of the optical path configuration to enhance the efficacy of reconstruction. This study presents a flame parameter field reconstruction model founded on laminar absorption spectroscopy. Furthermore, an optimization approach for refining the optical path configuration is delineated. In addressing non-axisymmetric flames, the simulated annealing algorithm (SA) and Harris's Hawk algorithm (HHO) are employed to optimize the optical path layout across varying beam quantities. The findings underscore a marked reduction in imaging errors with the optimized optical path configuration compared to conventional setups, thereby elevating detection precision. Notably, the HHO algorithm demonstrates superior performance over the SA algorithm in terms of optimization outcomes and computational efficiency. Compared with the parallel optical path, the optimized optical path of the HHO algorithm reduces the temperature field error by 25.5% and the concentration field error by 26.5%. [ABSTRACT FROM AUTHOR]

Recent decades have brought global expansion of private supplementary tutoring, and China is among countries in which patterns have been especially dramatic. National survey data indicate that 29.8% of primary and lower secondary students had received private supplementary tutoring in 2014, with proportions rising at higher levels of the school system. However, such statistics present only a snapshot of demand and might suggest that decisions to invest in tutoring are one-off in nature. This paper draws on interviews to show changing patterns of demand by individual parents at different times. Factors influencing parental choices include not only cost and availability of time but also children's academic performance, children's different stages of schooling and education system reforms. Over time parents may expand or reduce their demand, change balances between academic and non-academic tutoring, and switch between different types and providers of tutoring. This paper thus shows that analyses of demand need to be more nuanced than tends to be the case in analyses of large-scale survey data. The paper is grounded in the Chinese context, but has conceptual implications of wider relevance.

With the development of industrialization, chemical detection plays a vital role in many fields. As a new type of porous material, covalent organic frameworks (COF's) possess the characteristics of huge specific surface area, low density, great stability, and adjustable pore size. These characteristics make it a great prospect for chemical detection. In the article, we mainly show how to design several analytic platforms to achieve precise target detection by utilizing the special properties of COF's, put forward the relevant mechanisms of successful detections, and analyze the related parameters of analyte detection performance. Finally, the current challenges of chemical detection based on COF's are presented, and we also prospect the future research directions. [ABSTRACT FROM AUTHOR]