The surface plasmon (SP) sensing technique demonstrates high sensitivity and a broad bandwidth of measuring photoacoustic (PA) pressure transients. In this work, we further present a systematic investigation on PA response characteristics of the recently developed SP-based ultrasonic detector, where the ensemble of surface plasmon polaritons (SPPs) at the metal-dielectric interface is approximated as an equivalent acoustic detector. Relying on the intrinsically ultrafast temporal response (∼140 fs) and highly localized evanescent field (optical penetration depth of ∼185 nm) of the SPPs, the SP sensing can respond ultrasounds with the gigahertz frequency band theoretically, which, however, is far higher than the bandwidth in practical PA detection. We reveal that, due to acoustic interference, the finite lateral probing dimension in the SP sensor imposes an ultimate constraint on the accessible ultrasonic cutoff frequency, representing good agreement with the experimental results by acquiring PA impulses from an optically absorbing graphene film using our SP sensor. The theoretical framework enables analyzing the SP response characteristics of ultrasonic/PA pressure transients, which, therefore, offers guidelines for configuring the SP sensor with adequate sensitivity and bandwidths to access various biomedical PA applications, including volumetric imaging and spectroscopic analysis.

Sodium-ion batteries with evident merits in resource abundance and expenditure are emerging as a more suitable alternative to lithium-ion batteries for fulfilling the voracious energy demand of human activities. As the integral component of the battery, the exploration of anode materials suited to the electrochemical system during the last few decades has been never suspended, and the sodium metal anode successfully stands out with its high theoretical capacity and low redox potential. However, a huge gap exists between the direct usage of the sodium metal anode and the large-scale applications, as the uncontrollable sodium dendritic growth during cycling brings about serious concerns (i.e. infinite volume change, unstable solid electrolyte interphase, and safety issues) on battery performance losses. Although a few review articles on high-performance sodium metal anode have been already published, new research on solving the aforementioned challenges is still in progress. Therefore, we herein summarize the recent progress on the high-energy sodium metal anode from four aspects (protective layers, electrolyte additives, three-dimensional framework current collectors, and alloy materials) together with the detailed discussion and analysis in this Perspective. Furthermore, the potential directions and prospects of future research on constructing high-performance sodium metal anodes are also proposed.

Dihydromyricetin (DMY) is a principle bioactive component of the wild plant Ampelopsis grossedentata and possesses multiple pharmacological effects. However, the mechanism of its biological activity has not received much attention. In this study, the inhibitory mechanism of DMY was explored. Experiments were conducted to investigate the inhibitory effects of DMY on the proline metabolism of Vibrio parahaemolyticus by measurements of proline contents and proline dehydrogenase (PDH) activity. With DMY treatment, an increase in proline content and decrease in PDH activity were observed. Furthermore, molecular docking studies were used to confirm interaction mechanism of DMY with PDH. The results shown that DMY can interact with primary amino acid residues located within the active hydrophobic pockets of PDH, leading to decrease of PDH activity. The normal metabolism of proline was interfered by DMY, resulting in molecular damage and even death of V. parahaemolyticus cells. Practical applicationsThe antimicrobial mechanism of dihydromyricetin (DMY) on Vibrio parahaemolyticus at the molecular level is reported for the first time in this study. The molecular docking simulation provided supportive data for DMY-induced inhibition by allowing us to predict the binding site in the active site pocket of proline dehydrogenase. The data can be useful for future studies that involve evaluation of antibacterial mechanism of natural antimicrobial agents against foodborne pathogens and provide an insight into the structural and antibacterial properties of phenolic compounds. K E Y W O R D SDMY, molecular docking, PDH, proline metabolism, V. parahaemolyticus

Lipotoxicity has been shown to induce the loss of functional β-cell mass and lead to type 2 diabetes, but the mechanism remains unknown. In this study, we aim to explore the role of secretagogin (SCGN) in lipotoxicity-induced β-cell injury. Our results indicate that ox-LDL treatment leads to autophagic cell death, as evidenced by decreased cell viability, aggravated cell apoptosis, and the accumulation of the p62 protein in MIN6 cells. LysoTracker Red staining, TEM and mRFP-GFP-LC3 assays demonstrate that autophagic flux is blocked in ox-LDL-treated MIN6 cells. Intriguingly, SCGN is significantly decreased in MIN6 cells under lipotoxic conditions. Additionally, siRNA-guided SCGN knockdown blocks autophagic flux triggered by rapamycin, while SCGN restoration alleviates autophagic flux retardation and mitigates cell apoptosis. The physical interaction between SCGN and SNAP29 is validated by bioinformatics analysis, coimmunoprecipitation assay and SCGN knockdown test. Downregulation of SCGN expression reduces the interaction of these two proteins. Taken together, our results indicate that ox-LDL treatment induces apoptotic β-cell death by blocking autophagic flux dependent on SCGN downregulation. SCGN administration prevents lipotoxic β-cell injury and may be a potential therapeutic strategy to promote β-cell expansion in type 2 diabetes.

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