Search

In this study, constant‐amplitude fatigue tests were first performed on two types of reinforced concrete beams containing corroded reinforcements and carbonized concrete (involving corroded reinforcements). Then, the stiffness degradation behavior and the failure modes of these beams were analyzed. The results show that the stiffness of a beam first rapidly decreased and then slowly decreased under constant‐amplitude fatigue loading. In addition, the corrosion ratio of the reinforcement could affect the failure mode, and fatigue failure occurred in the compression zone of the concrete. Subsequently, a degradation equation of the bending stiffness for a damaged beam and a deflection equation that considers fatigue loads and accumulated damage were proposed. Furthermore, a staged linear curve for predicting the fatigue life of a reinforced concrete beam within certain corrosion ratio ranges was developed. [ABSTRACT FROM AUTHOR]

BACKGROUND Non‐target‐site resistance (NTSR) to herbicides is a serious threat to global agriculture. Although metabolic resistance is the dominant mechanism of NTSR, the molecular mechanisms are not yet well‐characterized. This study aimed to uncover the likely metabolism‐related genes in Beckmannia syzigachne (American sloughgrass) resistant to fenoxaprop‐p‐ethyl. RESULTS: Ultra‐performance liquid chromatography – tandem mass spectrometry experiments showed that the resistant American sloughgrass biotype (R, SD‐04‐SS) showed enhanced degradation of this herbicide compared to the susceptible biotype (S, SD‐12). R and S biotype were harvested at 24 h after fenoxaprop‐p‐ethyl treatment to conduct RNA sequencing (RNA‐Seq) analysis to investigate the likely fenoxaprop‐p‐ethyl metabolic genes. The RNA‐Seq libraries yield 417 969 980 clean reads. The de novo assembly generated 115 112 unigenes, of which 57 906 unigenes were annotated. Finally, we identified 273 cytochrome P450s, 178 oxidases, 47 glutathione S‐transferases (GSTs), 166 glucosyltransferases (GTs) and 180 ABC transporter genes to determine the likely fenoxaprop‐p‐ethyl metabolism‐related genes in R biotype. Twelve overlapping up‐regulated genes in the R biotype (fenoxaprop‐p‐ethyl‐treated R/non‐treated R, fenoxaprop‐p‐ethyl‐treated R/fenoxaprop‐p‐ethyl‐treated S) were identified by RNA‐Seq and the results were validated using qRT‐PCR. Ten were identified as fenoxaprop‐p‐ethyl metabolism‐related genes, including three P450s (homologous to CYP71D7, CYP99A2 and CYP71D10), one GST (homologous to GSTF1), two GTs (homologous to UGT90A1 and UGT83A1) and four oxidase genes. CONCLUSION: This work demonstrates that the NTSR mechanism by means of enhanced detoxification of fenoxaprop‐p‐ethyl in American sloughgrass is very likely driven by herbicide metabolism related genes. The RNA‐Seq data presented here provide a valuable resource for understanding the molecular mechanism of NTSR in American sloughgrass. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]