Background As the most abundant epigenetic modification on mRNAs and long non‐coding RNAs, N6‐methyladenosine (m6A) modification extensively exists in mammalian cells. Controlled by writers (methyltransferases), readers (signal transducers), and erasers (demethylases), m6A influences mRNA structure, maturation, and stability, thus negatively regulating protein expression in a post‐translational manner. Nevertheless, current understanding of m6A's roles in tumorigenesis, especially in gastric cancer (GC) remains to be unveiled. In this study, we assessed m6A's clinicopathological relevance to GC and explored the underlying mechanisms. Methods By referring to a proteomics‐based GC cohort we previously generated and the TCGA‐GC cohort, we merged expressions of canonical m6A writers (METTL3/METTL14), readers (YTHDF1/YTHDF2/YTHDF3), and erasers (ALKBH5/FTO), respectively, as W, R, and E signatures to represent m6A modification. We stratified patients according to these signatures to decipher m6A's associations with crucial mutations, prognosis, and clinical indexes. m6A's biological functions in GC were predicted by gene set enrichment analysis (GSEA) and validated by in vitro experiments. Results We discovered that W and R were potential tumor suppressive signatures, while E was a potential oncogenic signature in GC. According to W/R/E stratifications, patients with low m6A‐indications were accompanied with higher mutations of specific genes ( CDH1 , AR , GLI3 , SETBP1 , RHOA , MUC6 , and TP53 ) and also demonstrated adverse clinical outcomes. GSEA suggested that reduced m6A was correlated with oncogenic signaling and phenotypes. Through in vitro experiments, we proved that m6A suppression (represented by METTL14 knockdown) promoted GC cell proliferation and invasiveness through activating Wnt and PI3K‐Akt signaling, while m6A elevation (represented by FTO knockdown) reversed these phenotypical and molecular changes. m6A may also be involved in interferon signaling and immune responses of GC. Conclusions Our work demonstrated that low‐m6A signatures predicted adverse clinicopathological features of GC, while the reduction of RNA m6A methylation activated oncogenic Wnt/PI3K‐Akt signaling and promoted malignant phenotypes of GC cells.

Background: A previous study has shown that 81% of the COVID-19 patients had mild or moderate symptoms. However, most studies on the sequelae in COVID-19 patients focused on severe cases and the long-term follow-up studies on the health consequences in non-severe cases are limited. The current study aimed to assess the sequelae of COVID-19 in patients nearly 1 year after diagnosis with a particular focus on the recovery of patients with non-severe COVID-19.Methods: We enrolled 120 patients infected with SARS-CoV-2 discharged from Wuhan Union hospital west district (designated hospital for COVID-19) and Fangcang shelter hospitals between January 29, 2020 and April 1, 2020. All participants were asked to complete a series of questionnaires to assess their symptoms and quality of life and for psychological evaluation. Also, pulmonary function test, chest CT, 6-min walking test (6MWT), routine blood test, liver and kidney function tests, fasting blood glucose test, lipid test, and immunoglobulin G antibody test were performed to evaluate their health.Results: The mean age of the study population was 51.6 ± 10.8 years. Of the 120 patients, 104 (86.7%) were cases of non-severe COVID-19. The follow-up study was performed between November 23, 2020 and January 11, 2021, and the median time between the diagnosis and the follow-up was 314.5 (IQR, 296–338) days. Sleep difficulties, shortness of breath, fatigue, and joint pain were common symptoms observed during follow-up and nearly one-third of the non-severe cases had these symptoms. A total of 50 (41.7%) and 45 (37.5%) patients reported anxiety and depression, respectively. And 18.3% of the patients showed negative results in the IgG test at the follow-up, which correlated with the severity of the infection (R = 0.203, p = 0.026), and the proportion of IgG negative cases in non-severe COVID-19 patients was higher than that in the severe cases (20.2 vs. 6.3%). Pulmonary diffusion impairment was reported in 30 (26.1%) out of 115 patients, and 24 (24.2%) out of the 99 non-severe cases. The values of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FVC/FEV1, vital capacity (VC), total lung capacity (TLC), and residual volume (RV) were less than the normal range in 1.7, 8.6, 0.9, 11.2, 7.0, and 0.9% of the patients, respectively. A total of 55 (56.7%) out of the 97 patients showed abnormal CT findings, including ground-glass opacities (GGO), bronchiectasis, nodules, lines and bands, and fibrosis. Furthermore, there was a correlation between all the SF-36-domain scores and the duration of hospitalization, pulmonary function, and a 6MWT.Conclusions: At the nearly 1-year follow-up, COVID-19 survivors still had multi-system issues, including those in the respiratory functioning, radiography, quality of life, and anxiety and depression. Moreover, non-severe cases also showed some sequelae and the proportion of IgG negative cases in the non-severe patients was higher than that in severe cases. Therefore, conducting follow-ups and preventing the reinfection of SARS-CoV-2 in this group is necessary.

We report the results of a complete modal and non-modal linear stability analysis of the electrohydrodynamic flow for the problem of electroconvection in the strong-injection region. Convective cells are formed by the Coulomb force in an insulating liquid residing between two plane electrodes subject to unipolar injection. Besides pure electroconvection, we also consider the case where a cross-flow is present, generated by a streamwise pressure gradient, in the form of a laminar Poiseuille flow. The effect of charge diffusion, often neglected in previous linear stability analyses, is included in the present study and a transient growth analysis, rarely considered in electrohydrodynamics, is carried out. In the case without cross-flow, a non-zero charge diffusion leads to a lower linear stability threshold and thus to a more unstable flow. The transient growth, though enhanced by increasing charge diffusion, remains small and hence cannot fully account for the discrepancy of the linear stability threshold between theoretical and experimental results. When a cross-flow is present, increasing the strength of the electric field in the high-Re Poiseuille flow yields a more unstable flow in both modal and non-modal stability analyses. Even though the energy analysis and the input-output analysis both indicate that the energy growth directly related to the electric field is small, the electric effect enhances the lift-up mechanism. The symmetry of channel flow with respect to the centreline is broken due to the additional electric field acting in the wall-normal direction. As a result, the centres of the streamwise rolls are shifted towards the injector electrode, and the optimal spanwise wavenumber achieving maximum transient energy growth increases with the strength of the electric field.