Search

Flexible perovskite solar cells often experience constant or cyclic bending during their service life. Catastrophic failure of devices may occur due to the crack of polycrystalline perovskite films and delamination at the perovskite and the substrate interfaces, posing a significant stability concern. Here, a multiple dynamic hydrogen bonding polymer network is developed to enhance the mechanical strength of flexible perovskite solar cells in two ways. The main chain of poly(acrylic acid) decreases the mismatch of the coefficient of thermal expansion between the perovskite and the substrate by 16.7% through its flexibility and spatial occupation. The dopamine branch chains provide multiple dynamic hydrogen bonding sites, which contribute to increased energy dissipation upon stress deformation and reduce Young's modulus of perovskite by 54.3%. The inverted flexible perovskite solar cells achieve a champion power conversion efficiency of 23.02% and retain 81.3% of the initial PCE over 2000 h under continuous 1‐sun equivalent illumination. Moreover, devices show excellent mechanical stability by remaining 90.2% of the original value after 5000 bending cycles. [ABSTRACT FROM AUTHOR]

The persistent heavy precipitation that occurred in most of West China (WC) during August 11–18, 2020, generated the highest rainfall record since recording began in 1961 and was selected as one of the top 10 worst national natural disasters of 2020 in China. Favorable circulation was sustained during August; WC was positioned between two anomalous high-pressure centers over the Tibetan Plateau and Sea of Japan and an anomalous low-pressure center over Mongolia located on its north side, which created a stable and long trough and formed a low-pressure center over WC. At 200 hPa, the subtropical westerly jet was much stronger than average and southward, and the South Asian High (SAH) was strong and extended eastward to 150°E. At 500 hPa, the western Pacific subtropical high (WPSH) was westward and exceptionally strong, which helped abundant water vapor reach the southeastern part of WC and provided favorable dynamic and thermodynamic conditions for precipitation in this region. In addition, the eastward extension of the SAH promotes the westward extension of WPSH, which collectively enhanced the precipitation in WC. At 850 hPa, the low-level jet corresponding to the west-extending subtropical high from the Sea of Japan to WC further enhanced and guided the water vapor transport to WC. In addition, the Mei-Yu front over the Yangtze River Basin in June and July strengthened the northwestward spread of diabatic heating, transient energy, and wave activity fluxes, which likely influenced the large-scale circulation factors and reinforced the precipitation in WC in August 2020.

As software grows in size and complexity, software vulnerabilities are increasing, leading to a range of serious insecurity issues. Open‐source software vulnerability reports and documentation can provide researchers with great convenience for analysis and detection. However, the quality of different data sources varies, the data are duplicated and lack of correlation, which often requires a lot of manual management and analysis. In order to solve the problems of scattered and heterogeneous data and lack of correlation in traditional vulnerability repositories, this paper proposes a software vulnerability feature knowledge extraction method that combines the N‐gram model and mask similarity. The method generates mask text data based on the extraction of N‐gram candidate keywords and extracts vulnerability feature knowledge by calculating the similarity of mask text. This method analyzes the samples efficiently and stably in the environment of large sample size and complex samples and can obtain high‐value semi‐structured data. Then, the final node, relationship, and attribute information are obtained by secondary knowledge cleaning and extraction of the extracted semi‐structured data results. And based on the extraction results, the corresponding software vulnerability domain knowledge graph is constructed to deeply explore the semantic information features and entity relationships of vulnerabilities, which can help to efficiently study software security problems and solve vulnerability problems. The effectiveness and superiority of the proposed method is verified by comparing it with several traditional keyword extraction algorithms on Common Weakness Enumeration (CWE) and Common Vulnerabilities and Exposures (CVE) vulnerability data. [ABSTRACT FROM AUTHOR]

Engineering acid-tolerant microbial strains is a cost-effective approach to overcoming acid stress during industrial fermentation. We previously constructed an acid-tolerant strain (Escherichia coli SC3124) with enhanced growth robustness and productivity under mildly acidic conditions by fine-tuning the expression of synthetic acid-tolerance module genes consisting of a proton-consuming acid resistance system (gadE), a periplasmic chaperone (hdeB), and ROS scavengers (sodB, katE). However, the precise acid-tolerance mechanism of E. coli SC3124 remained unclear. In this study, the growth of E. coli SC3124 under mild acid stress (pH 6.0) was determined. The final OD600 of E. coli SC3124 at pH 6.0 was 131% and 124% of that of the parent E. coli MG1655 at pH 6.8 and pH 6.0, respectively. Transcriptome analysis revealed the significant upregulation of the genes involved in oxidative phosphorylation, the tricarboxylic acid (TCA) cycle, and lysine-dependent acid-resistance system in E. coli SC3124 at pH 6.0. Subsequently, a weighted gene coexpression network analysis was performed to systematically determine the metabolic perturbations of E. coli SC3124 with mild acid treatment, and we extracted the gene modules highly associated with different acid traits. The results showed two biologically significant coexpression modules, and 263 hub genes were identified. Specifically, the genes involved in ATP-binding cassette (ABC) transporters, oxidative phosphorylation, the TCA cycle, amino acid metabolism, and purine metabolism were highly positively associated with mild acid stress responses. We propose that the overexpression of synthetic acid-tolerance genes leads to metabolic changes that confer mild acid stress resistance in E. coli. Integrated omics platforms provide valuable information for understanding the regulatory mechanisms of mild acid tolerance in E. coli and highlight the important roles of oxidative phosphorylation and ABC transporters in mild acid stress regulation. These findings offer novel insights to better the design of acid-tolerant chasses to synthesize value-added chemicals in a green and sustainable manner. [ABSTRACT FROM AUTHOR]

An automated task for finding the essential buggy files among software projects with the help of a given bug report is termed bug localization. The conventional approaches suffer from the challenges of performing lexical matching. Particularly, the terms utilized for describing the bugs in the bug reports are observed to be irrelevant to the terms used in the source code files. To resolve these problems, we propose an optimized and ensemble deep learning model for software bug localization. These features are reduced by the principle component analysis (PCA). Then, they are selected by the weighted convolutional neural network (CNN) model with the support of the Modified Scatter Probability‐based Coyote Optimization Algorithm (MSP‐COA). Finally, the optimal features are subjected to the ensemble deep neural network and long short‐term memory (DNN‐LSTM), with parameter tuning by the MSP‐COA. Experimental results show that the proposed approach can achieve higher bug localization accuracy than individual models. [ABSTRACT FROM AUTHOR]

The excited-state intramolecular proton transfer (ESIPT) process involving dual hydrogen bond acceptors (HBAs) is of great interest in research and has significant potential for applications due to its flexible adjustability. In this work, the solvent polarity-dependent changes in structures, photophysical properties and ESIPT processes of 2-(2-hydroxy-3-hydroxyiminomethyl-5-methylphenyl)-benzimidazole (HHMB) with two asymmetric HBAs are investigated. Firstly, the orientation of intramolecular hydrogen bond (IHB) under different solvent polarities are explored. The computational results indicate that in non-polar solvents, the central hydroxyl group predominantly forms an IHB with the imine of the oxime group, resulting in large Stokes and near-infrared emission peaks. Conversely, in polar solvents, the central hydroxyl group links the imidazole group to form a stronger IHB with improved fluorescence efficiency. Additionally, the quantum chemical calculations are used to simulate the absorption–emission spectra and plot the frontier molecular orbitals, as well as the potential energy curves about ESIPT in different solvents. In conclusion, we elucidate the rationale behind the preferential formation of the biased IHBs and examine its impact on the ESIPT process by manipulating the solvent polarity. Theoretical studies on the dual HBAs molecule, exhibiting specific selectivity, pave the way for the development of higher-performance fluorescence probes and luminescent materials. [ABSTRACT FROM AUTHOR]

Background: Serotonin (5‐hydroxytryptamine) is a multifunctional bioamine serving as a neurotransmitter, peripheral hormone and mitogen in the vertebrate system. It has pleiotropic activities in central nervous system and gastrointestinal function via an orchestrated action of serotonergic elements, particularly serotonin receptor‐mediated signalling cascades. The mitogenic properties of serotonin have garnered recognition for years and have been exploited for repurposing serotonergic‐targeted drugs in cancer therapy. However, emerging conflicting findings necessitate a more comprehensive elucidation of serotonin's role in cancer pathogenesis. Main body and conclusion: Here, we provide an overview of the biosynthesis, metabolism and action modes of serotonin. We summarise our current knowledge regarding the effects of the peripheral serotonergic system on tumourigenesis, with a specific emphasis on its immunomodulatory activities in human cancers. We also discuss the dual roles of serotonin in tumour pathogenesis and elucidate the potential of serotonergic drugs, some of which display favourable safety profiles and impressive efficacy in clinical trials, as a promising avenue in cancer treatment. Key points: Primary synthesis and metabolic routes of peripheral 5‐hydroxytryptamine in the gastrointestinal tract.Advanced research has established a strong association between the serotonergic components and carcinogenic mechanisms.The interplay between serotonergic signalling and the immune system within the tumour microenvironment orchestrates antitumour immune responses.Serotonergic‐targeted drugs offer valuable clinical options for cancer therapy. [ABSTRACT FROM AUTHOR]