Discovery of Cysteine and Its Derivatives as Novel Antiviral and Antifungal Agents

Based on the structure of the natural product cysteine, a series of thiazolidine-4-carboxylic acids were designed and synthesized. All target compounds bearing thiazolidine-4-carboxylic acid were characterized by 1H-NMR, 13C-NMR, and HRMS techniques. The antiviral and antifungal activities of cysteine and its derivatives were evaluated in vitro and in vivo. The results of anti-TMV activity revealed that all compounds exhibited moderate to excellent activities against tobacco mosaic virus (TMV) at the concentration of 500 μg/mL. The compounds cysteine (1), 3–4, 7, 10, 13, 20,23, and 24 displayed higher anti-TMV activities than the commercial plant virucide ribavirin (inhibitory rate: 40, 40, and 38% at 500 μg/mL for inactivation, curative, and protection activity in vivo, respectively), especially compound 3 (inhibitory rate: 51%, 47%, and 49% at 500 μg/mL for inactivation, curative, and protection activity in vivo, respectively) with excellent antiviral activity emerged as a new antiviral candidate. Antiviral mechanism research by TEM exhibited that compound 3 could inhibit virus assembly by aggregated the 20S protein disk. Molecular docking results revealed that compound 3 with higher antiviral activities than that of compound 24 did show stronger interaction with TMV CP. Further fungicidal activity tests against 14 kinds of phytopathogenic fungi revealed that these cysteine derivatives displayed broad-spectrum fungicidal activities. Compound 16 exhibited higher antifungal activities against Cercospora arachidicola Hori and Alternaria solani than commercial fungicides carbendazim and chlorothalonil, which emerged as a new candidate for fungicidal research

Hall-Petch relationship of interstitial-free steel with a wide grain size range processed by asymmetric rolling and subsequent annealing

Asymmetric rolling (ASR) is an efficient processing for fabricating ultrafine-grained (UFG) materials. In the present investigation, interstitial-free (IF) steels with the grain size ranged from 500 nm to 500 μ m were obtained by asymmetric rolling and subsequent annealing. The evolution of microstructures and mechanical properties of IF steel were studied. Accordingly, the Hall-Petch relationship of IF steel with a wide grain size range was established. It was found that ultimate tensile strength (UTS) corresponds well to the Hall-Petch relationship over the whole grain size range. However, the yield strength (YS) and hardness deviated from the Hall-Petch relationship as the grain size is larger than 100 μ m, which is mainly attributed to the slight effect of grain boundary as obstacle on the dislocation movement and/or pile-up under small deformation in coarse grain (CG)

Surface Structuring via Additive Manufacturing to Improve the Performance of Metal and Polymer Joints

In order to enhance the joint performance of Ti6Al4V titanium alloy (TC4) and ultra-high molecular weight polyethylene (UHMWPE) for biomedical applications, different structures were fabricated on TC4 surfaces via electron beam melting (EBM) method in this study. Macromorphologies and microinterfaces of TC4–UHMWPE joints produced via hot pressing technique were carefully characterized and analyzed. The effects of different surface structures on mechanical properties and fractured surfaces were investigated and compared. Strong direct bonding (1751 N) between UHMWPE and TC4 was achieved. The interfacial bonding behavior of TC4–UHMWPE joints was further discussed. This study demonstrates the importance of combining macro- and micromechanical interlocking, which is a promising strategy for improving metal–polymer joint performance. It also provides guidance for metal surface structuring from both theoretical and practical perspectives

A quantitative method to characterize the Al4C3-formed interfacial reaction: The case study of MWCNT/Al composites

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