Background As a DNA surveillance mechanism, cell cycle checkpoint has recently been discovered to be closely associated with lung adenocarcinoma (LUAD) prognosis. It is also an essential link in the process of DNA damage repair (DDR) that confers resistance to radiotherapy. Whether genes that have both functions play a more crucial role in LUAD prognosis remains unclear. Methods In this study, DDR-related genes with cell cycle checkpoint function (DCGs) were selected to investigate their effects on the prognosis of LUAD. The TCGA-LUAD cohort and two GEO external validation cohorts (GSE31210 and GSE42171) were performed to construct a prognosis model based on the least absolute shrinkage and selection operator (LASSO) regression. Patients were divided into high-risk and low-risk groups based on the model. Subsequently, the multivariate COX regression was used to construct a prognostic nomogram. The ssGSEA, CIBERSORT algorithm, TIMER tool, CMap database, and IC50 of chemotherapeutic agents were used to analyze immune activity and responsiveness to chemoradiotherapy. Results 4 DCGs were selected as prognostic signatures, and patients in the high-risk group had a lower overall survival (OS). The lower infiltration levels of immune cells and the higher expression levels of immune checkpoints appeared in the high-risk group. The damage repair pathways were upregulated, and chemotherapeutic agent sensitivity was poor in the high-risk group. Conclusions The 4-DCGs signature prognosis model we constructed could predict the survival rate, immune activity, and chemoradiotherapy responsiveness of LUAD patients.

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In order to improve the character of common cement mortar which are brittle and easily cracked, andtotake advantage of the local materials, abandoned fishing nets was used toform get the cement-based fiber materials. In this study, the influence of the amount and length of abandoned fishing nets on the mechanical properties of cement mortar and its mechanism were discussed. Four different lengths of abandoned fishing nets were adopted under four kinds of dosages to mix with mortar and make a total of 16 test blocks. Then the flexural strengths of the prepared test blocks were tested, and the load-deflection curve of the test block was obtained. The results showthat the residual strength after the test block after which reachesthe peak load in the flexural test generally increases with the increase of the fiber content and the length of the fiber, but when the dosage and length increase to a certain range, the influences becomecomplicated. The crack propagation simulation byAbaqus further revealed the reinforcement mechanism, and it can be concluded thatthe bridging between the fiber and the matrix has a great influence on the character toughness.