Search

The SPRY domain-containing SOCS box proteins SPSB1, SPSB2, and SPSB4 utilize their SPRY/B30.2 domain to interact with a short region in the N-terminus of inducible nitric oxide synthase (iNOS), and recruit an E3 ubiquitin ligase complex to polyubiquitinate iNOS, resulting in the proteasomal degradation of iNOS. Inhibitors that can disrupt the endogenous SPSB-iNOS interactions could be used to augment cellular NO production, and may have antimicrobial and anticancer activities. We previously reported the rational design of a cyclic peptide inhibitor, cR8, cyclo(RGDINNNV), which bound to SPSB2 with moderate affinity. We, therefore, sought to develop SPSB inhibitors with higher affinity. Here, we show that cyclic peptides cR7, cyclo(RGDINNN), and cR9, cyclo(RGDINNNVE), have ~6.5-fold and ~2-fold, respectively, higher SPSB2-bindng affinities than cR8. We determined high-resolution crystal structures of the SPSB2-cR7 and SPSB2-cR9 complexes, which enabled a good understanding of the structure–activity relationships for these cyclic peptide inhibitors. Moreover, we show that these cyclic peptides displace full-length iNOS from SPSB2, SPSB1, and SPSB4, and that their inhibitory potencies correlate well with their SPSB2-binding affinities. The strongest inhibition was observed for cR7 against all three iNOS-binding SPSB proteins. [ABSTRACT FROM AUTHOR]

In response to the phenomenon that road maintenance construction activities may have a certain impact on passing vehicles and generate additional carbon emissions, based on the Tianjin Avenue Restoration and Maintenance Project, a recommended list of carbon emission factors is proposed. A traffic impact carbon emission calculation model is used to calculate the traffic impact carbon emissions of the supporting project, analyze the characteristics of traffic impact carbon emissions composition, and explore the hot spots of traffic impact carbon emissions of maintenance projects, propose emission reduction strategies for road maintenance engineering traffic organization.

Surface-enhanced Raman scattering is a powerful spectroscopy technique due to its ultra-sensitive characterization. However, it is usually detected based on direct contact between the noble metal substrates and the probe molecule, which limits the practical applications. Here, we propose a detection method to construct an all-inorganic perovskite CsPbIBr2 on the surface of a silver nanofilm for surface-enhanced Raman scattering applications. The perovskite film is coated on the surface of a silver nanofilm as the protection layer and a signal amplifier to achieve high sensitivity detection without direct contact between the probe molecule and the noble metal layer. The interaction and enhancement mechanism between the components were discussed, which provided a lower detection limit for the analysis of p-mercaptobenzoic acid and rhodamine. This study provides an easy-to-prepare and high-sensitivity perovskite-based substrate for SERS-related applications, promotes the understanding of charge transfer in nanocomposite substrates, expands the class of SERS substrates, and is conducive to providing a wide range of applications and platforms in various fields. [ABSTRACT FROM AUTHOR]

In order to improve the thermal stability of perovskite solar cells (PSCs) and reduce production costs, hole transport layer (HTL)‐free carbon‐based CsPbI3 PSCs (C‐PSCs) have attracted the attention of researchers. However, the power conversion efficiency (PCE) of HTL‐free CsPbI3 C‐PSCs is still lower than that of PSCs with HTL/ metal electrodes. This is because the direct contact between the carbon electrode and the perovskite layer has a higher requirement on the crystal quality of perovskite layer and matched energy level at perovskite/carbon interface. Herein, the acyl chloride group and its derivative trichloroacetyl chloride are used to passivate CsPbI3 C‐PSCs for the first time. The results show that the carbonyl group of trichloroacetyl chloride can effectively passivate the uncoordinated Pb2+ ions in perovskite. At the same time, leaving group Cl− ions can increase the grain size of perovskite and improve the crystallization quality of perovskite layer. In addition, the trichloroacetyl chloride tends to generate cesium chloride acetate, which acts as an electron blocking layer, reduces charge recombination, promotes gradient energy level arrangement, and effectively improves the separation and extraction ability of carriers. The PCE of CsPbI3 HTL‐free C‐PSCs is successfully increased from 13.40% to 14.82%. [ABSTRACT FROM AUTHOR]

Single-atom nanozymes (SAzymes) are emerging as promising alternatives to mimic natural enzyme, which is due to high atomic utilization efficiency, well-defined geometric, and unique electronic structure. Herein, Fe single atoms supported on Ti3C2Tx (Fe-SA/Ti3C2Tx) with intrinsic peroxidase activity is developed, further constructing a sensitive Raman sensor array for sensing of five antioxidants. Fe-SA/Ti3C2Tx shows excellent peroxidase-like performance in catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) with colorimetric reactions. X-ray adsorption fine structure (XAFS) reveals that the electron transport between the Ti3C2Tx and Fe atoms occurs along Fe-O-Ti ligands, meanwhile the density functional theory (DFT) calculations confirm the spontaneous dissociation of H2O2 and the formation of OH radicals. Furthermore, the peroxidase-like Fe-SA/Ti3C2Tx was used as surface enhanced Raman scattering (SERS) substrate of oxidized TMB (TMB+) and achieved satisfied signal amplification performance. Using the blocking effects of free radical reactions, one-off identification of 5 antioxidants, including ascorbic acid (AA), uric acid (UA), glutathione (GSH), melatonin (Mel), and tea polyphenols (TPP), could be realized with this high identifiable catalytic property. This principle could realize 100% distinguish accuracy combined with linear discriminant analysis (LDA) and heat map data analysis. A wide detection concentration ranges from 10−8 to 10−3 M for five antioxidants was also achieved. [ABSTRACT FROM AUTHOR]