Search

Vibration analysis of vehicle-bridge coupled systems has received considerable attentions over the past two decades. This work is dedicated to the stochastic dynamic analysis of vehicle-bridge coupled systems with nonlinear Hertz wheel-rail contacts subjected to random track irregularities. An explicit time-domain method (ETDM) is proposed for efficient nonlinear dynamic analysis of vehicle-bridge coupled systems with a dimension-reduced iteration scheme focusing on the nonlinear wheel-rail contact forces. The high-efficient ETDM is further utilised to implement the numerous nonlinear dynamic analyses required in the Monte-Carlo simulation (MCS) for obtaining the response statistics of the vehicle-bridge coupled systems. A numerical example involving a single-wheel vehicle traversing a simply-supported beam with nonlinear Hertz wheel-rail contacts considering random track irregularities is presented to demonstrate the computational accuracy and efficiency of the proposed method, and an engineering application involving a four-wheel vehicle moving across the Egongyan suspension bridge is further analysed to indicate the effectiveness of the proposed method for large-scale engineering problems. [ABSTRACT FROM AUTHOR]

Chemotherapy is currently the main treatment for unresectable or advanced postoperative gastric cancers. However, its efficacy is negatively affected by the occurrence of chemoresistance, which severely affects patient prognosis. Recently, dysregulation in autophagy has been suggested as a potential mechanism for chemoresistence, and long noncoding RNA (lncRNA) also shows its regulatory role in cancer drug resistance. Using RNA sequencing, we found that lncRNA EIF3J-DT was highly expressed in drug-resistant gastric cancer cells. In-vitro and in-vivo experiments showed that EIF3J-DT activated autophagy and induced drug resistance in gastric cancer cells by targeting ATG14. Bioinformatics and experimental results showed that EIF3J-DT regulated the expression of ATG14 through direct binding to enhance stabilization of ATG14 mRNA and via blocking the degradation of ATG14 mRNA through competitively binding with microRNA (miRNA) MIR188-3p. Therefore, EIF3J-DT increased the expression of ATG14, contributing to activation of autophagy and chemoresistance. Furthermore, it was confirmed that EIF3J-DT and ATG14 were highly expressed in gastric cancer patients resistant to chemotherapy, and this was closely associated with patient prognosis. In conclusion, EIF3J-DT is involved in the regulation of autophagy and chemoresistance in gastric cancer cells by targeting ATG14. It may be a suitable new target for enhancing chemosensitivity and improving prognosis. Abbreviations: 3-MA: 3-methyladenine; 5-Fu: 5-fluorouracil; ATG: autophagy related; C-CASP3: cleaved caspase 3; C-CASP7: cleaved caspase 7; C-PARP: cleaved PARP; CQ: chloroquine; CR: complete response; DIG: digoxigenin; ESR1: estrogen receptor 1; FBS: fetal bovine serum; FISH: fluorescence in situ hybridization; IHC: immunohistochemistry; ISH: in situ hybridization; lncRNA: long noncoding RNA; miRNA: microRNA; MUT: mutant; NC: negative control; OXA: oxaliplatin; PBS: phosphate-buffered saline; PD: progressive disease; PFA: paraformaldehyde; PR: partial response; qPCR: quantitative polymerase chain reaction; RAPA: rapamycin; SD: stable disease; TEM: transmission electron microscopy; WT: wild type. [ABSTRACT FROM AUTHOR]

Background: Anaplastic lymphoma kinase (ALK) is a validated molecular target in non-small-cell lung cancer (NSCLC). However, the clinical benefits of ALK inhibitors are almost universally limited by the emergence of drug resistance. Methods: We monitored the plasma circulating tumor DNA (ctDNA) using captured-based ultra-deep sequencing analysis of one patient with metastatic ALK-positive NSCLC who had received therapies including first-, second- and third-generation ALK inhibitors. Functional in vitro studies were further undertaken to elucidate the mechanism of resistance. Results: ALK T1151Sins mutation was detected when the patient developed resistance to ceritinib, and undetectable when she responded to lorlatinib. MET amplification was present when the tumor developed resistance to lorlatinib, and reduced when the patient received combination therapy of lorlatinib with crizotinib, which corresponded to clinical radiologic responses. In addition, further functional in vitro studies demonstrated that ALK harboring the T1151Sins mutation, while conferring resistance to ceritinib, was inhibited by lorlatinib. Conclusions: Clinical evidence and in vitro validation revealed the clinical usefulness of captured-base ultra-deep sequencing on longitudinal plasma ctDNA in revealing the underlying resistance mechanism and guiding the precise administration of ALK inhibitors in patients with advanced ALK-positive NSCLC. [ABSTRACT FROM AUTHOR]