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The detection and localization of weak sound sources are a topic of great interest in a wide range of applications, but generally require a pressure amplification and directivity acoustic system. Although acoustic technologies have been advanced in recent years, the realization of pressure amplification and directivity acoustic systems remains a slippery subject. Here, we propose a gradient acoustic metamaterial (GAM) coupled with space-coiling structure (GAM-SCS) for the detection and localization of weak sound sources. The GAM-SCS is evaluated both numerically and experimentally. Compared with the GAM without space-coiling structure, the GAM-SCS has a better pressure amplification performance which enables the sound signals to be pre-amplified. Meanwhile, the induced space-coiling structure, making use of subwavelength features, also enables the GAM-SCS to work in a lower frequency. Furthermore, the directivity of the GAM-SCS also shines lights on directional acoustic sensing to resist noise interference. We believe that this work opens up a new vista to realize the detection and localization of weak sound sources based on acoustic metamaterials. [ABSTRACT FROM AUTHOR]

• Phononic crystal (PC) point defects coupled with Helmholtz resonators is proposed. • Coupled resonator (CPCR) can realize acoustic enhancement and directional sensing. • The CPCR helps overcome the detection limit of conventional acoustic systems. • The CPCR can be used for sound source localization. The detection and localization of acoustic signals play a vital role in many areas, such as structural health monitoring, gas pipeline leakage detection and underwater acoustic communication. However, the realization of both high-sensitivity and high-directivity acoustic systems at the same time remains a slippery subject. Besides, the detection limit, namely the detection capability of minimal detectable pressure, of sensitivity and directivity still hinders the performance of ordinary acoustic sensors where weak signals or low signal to noise ratios (SNRs) exist. Here, we propose a structure that couples phononic crystal (PC) point defects with four-sided Helmholtz resonators (HRs) to realize acoustic enhancement and directional sensing simultaneously in a high energy density cavity. The proposed coupled PC resonator (CPCR) shows a much better acoustic enhancement performance than PC point defects or four-sided HRs individually. Meanwhile, the remarkable directional response of the CPCR ensures the success in directional sensing. Furthermore, both in numerical and experimental studies, we demonstrate that the CPCR can be regarded as an acoustic device or sensor to detect harmonic signals and Gaussian pulse signals effectively. This work breaks through the detection limit of conventional acoustic sensing systems and provides a new routine for the development of coupled acoustic sensing devices that are highly desirable in practical engineering applications. [ABSTRACT FROM AUTHOR]

Since its discovery, anthraquinone has become very valuable as a lead compound in the development of anti-cancer drugs. Previously, we designed and synthesized a new type of amide anthraquinone derivative (1-nitro-2-acylanthraquinone glycine, C10) with good activity against colon cancer. However, its effect and the underlying mechanism are unclear. In this study, C10 significantly inhibited the proliferation of HCT116 and HT29 colon cancer cells by blocking the cell cycle at the G2/M phase. C10 also plays a role in cell cycle arrest by reducing the protein and gene expression levels of cyclin B1 and its downstream signaling molecule cyclin-dependent kinase (CDK1). In addition, molecular docking studies showed that C10 has high affinity for Jak2, the first target in the cell cycle-related Jak2/Stat3 signaling pathway. Furthermore, C10 downregulated the expression of Jak2/Stat3 signaling pathway-related signaling molecules proteins and genes, and up-regulated the expression of PIAS-3, the upstream signaling molecule of Stat3, thereby down-regulating Stat3 phosphorylation. C10 reversed the expression of Jak2/Stat3 signaling pathway-related molecules activated by IL-6. Overall, our results indicate for the first time that C10 induces cell cycle arrest and inhibits cell proliferation by inhibiting the Jak2/Stat3 signaling pathway. This study provides new insights into the potential role of Jak2/Stat3 in the regulating cell cycle-related signaling pathways that mediate the inhibitory effects of C10 on colon cancer cell proliferation. [Display omitted] • C10 significantly inhibited the proliferation of colon cancer cells. • C10 induced the cell cycle arrest by regulating the Jak/Stat3 signaling pathway. • PIAS-3 play a essential role on C10 down-regulates the expression level of Stat3. [ABSTRACT FROM AUTHOR]