The crystal structure of a material creates a periodic potential that electrons move through giving rise to its electronic band structure. When two-dimensional materials are stacked, the resulting ...moiré pattern introduces an additional periodicity so that the twist angle between the layers becomes an extra degree of freedom for the resulting heterostructure. As this angle changes, the electronic band structure is modified leading to the possibility of flat bands with localized states and enhanced electronic correlations1–6. In transition metal dichalcogenides, flat bands have been theoretically predicted to occur for long moiré wavelengths over a range of twist angles around 0° and 60° (ref. 4) giving much wider versatility than magic-angle twisted bilayer graphene. Here, we show the existence of a flat band in the electronic structure of 3° and 57.5° twisted bilayer WSe2 samples using scanning tunnelling spectroscopy. Our direct spatial mapping of wavefunctions at the flat-band energy show that the localization of the flat bands is different for 3° and 57.5°, in agreement with first-principles density functional theory calculations4.Using scanning tunnelling spectroscopy, the flat bands in twisted bilayer WSe2 are shown near both 0° and 60° twist angles.
In this study, we analyzed the influence of process parameters on the diameter and orientation of nanofibers electrospun with alternating current (AC), using surface response methodology. The design ...of experiment was adopted with four main process parameters: solution concentration, collection distance, voltage and collection speed. The morphology of nanofibers was examined with a scanning electron microscope. Nanofiber orientation was characterized by the fast Fourier transform method. We used the Box-Behnken design model to predict the diameter and orientation of the nanofibers, and the results showed good agreement with the measured results. The results also indicated that solution concentration and collection speed have a similar influence on fiber diameter and orientation, as in the case of direct current electrospinning. Furthermore, in this study, we optimized the process parameters to generate thinner nanofibers with better alignment, and it also can be used as a reference to make nanofiber yarns with AC electrospinning.
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•We studied the parameter effects on the AC electrospun nanofiber diameter and orientation with response surface methodology.•We used the Box-Behnken design model to predict the nanofiber diameter and orientation.•Concentration and collection speed had similar influences on fiber diameter and orientation in AC and DC electrospinning.
In recent years, research on ventilating tunnels has become increasingly important. However, the impact of external disturbances on ventilating systems has been largely ignored. To address this issue ...of frequent airflow fluctuations caused by external perturbations, which cannot be fully compensated using conventional control methods, this study proposes a perturbation-compensated ventilation control approach. A disturbance compensator is developed by incorporating the tunnel's airflow velocity and the number of jet fan start-stop events as input parameters. By compensating for external disturbances, the disturbance to the system is reduced. The Simulink model of the tunnel controller was used for simulation experiments. The compensator demonstrated good tracking results in comparison experiments with different disturbances. The ventilation approach based on disturbance compensator is capable of regulating the fluctuation of CO concentration within a justifiable range compared to using PID control and ADRC. This not only improves the stability of the entire control system but also significantly prolongs the service life of the jet fan by reducing the frequency of start-stop cycles.
Accumulating evidence suggested that epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) characteristics, both of which contribute to tumor invasion and metastasis, are interrelated ...with miR-21. MiR-21 is one of the important microRNAs associated with tumor progression and metastasis, but the molecular mechanisms underlying EMT and CSC phenotype during miR-21 contributes to migration and invasion of breast cancer cells remain to be elucidated.
In this study, MDA-MB-231/anti-miR-21 cells were established by transfected hsa-miR-21 antagomir into breast cancer MDA-MB-231 cells. EMT was evaluated by the changes of mesenchymal cell markers (N-cadherin, Vimentin, and alpha-SMA), epithelial cell marker (E-cadherin), as well as capacities of cell migration and invasion; CSC phenotype was measured using the changes of CSC surface markers (ALDH1 and CD44), and the capacity of sphereforming (mammospheres). We found that antagonism of miR-21 reversed EMT and CSC phenotype, accompanied with PTEN up-regulation and AKT/ERK1/2 inactivation. Interestingly, down-regulation of PTEN by siPTEN suppressed the effects of miR-21 antagomir on EMT and CSC phenotype, confirming that PTEN is a target of miR-21 in reversing EMT and CSC phenotype. The inhibitors of PI3K-AKT and ERK1/2 pathways, LY294002 and U0126, both significantly suppressed EMT and CSC phenotype, indicating that AKT and ERK1/2 pathways are required for miR-21 mediating EMT and CSC phenotype.
In conclusion, our results demonstrated that antagonism of miR-21 reverses EMT and CSC phenotype through targeting PTEN, via inactivation of AKT and ERK1/2 pathways, and showed a novel mechanism of which might relieve the malignant biological behaviors of breast cancer.
Schematic of the coastal microorganism-mediated dissolved organic matter transformation.
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•Bacteria transformed the DOM from a relatively high to a low molecular weight.•Microbial ...transformation render “dark” organic matter visible in mass spectrometry.•K- and r-strategists showed different correlations with two-size categories of DOM.•DOM chemodiversity and microbial biodiversity exhibited tight connections.•DOM variations are more crucial in shaping microbial communities than vice versa.
Dissolved organic matter (DOM) changes in quantity and quality over time and space, especially in highly dynamic coastal estuaries. Bacterioplankton usually display seasonal and spatial variations in abundance and composition in the coastal regions, and influence the DOM pool via assimilation, transformation and release of organic molecules. The change in DOM can also affect the composition of bacterial community. However, little is known on the correspondence between DOM molecules and bacterial composition, particularly through a systematic field survey. In this study, the spatiotemporal signatures of microbial communities and DOM composition in the subtropical coastal estuary of Xiamen are investigated over one and half years. The co-occurrence analysis between bacteria and DOM suggested microorganisms likely transformed the DOM from a relatively high (>400 Da) to a low (<400 Da) molecular weight, corresponding to an apparent increase in overall aromaticity. This might be the reason why microbial transformation renders “dark” organic matter visible in mass spectrometry due to more efficient ionization of microbial metabolites, as well as photodegradation processes. K- and r-strategists exhibited different correlations with two-size categories of DOM molecules owing to their different lifestyles and responses to environmental nutrient conditions. A comparison of the environmental variables and DOM composition with the microbial communities showed that the environmental/DOM variations played a more important role in shaping the microbial communities than vice versa. This study sheds light on the interactions between microbial populations and DOM molecules at the spatiotemporal scale, improving our understanding of microbial roles in marine biogeochemical cycles.
G protein-coupled receptor 120 (GPR120) has been shown to negatively regulate inflammation and apoptosis, but its role in cerebral ischemic injury remains unclear. Using an in vivo model of middle ...cerebral artery occlusion (MCAO) and an in vitro model of oxygen-glucose deprivation (OGD), we investigated the potential role and molecular mechanisms of GPR120 in focal cerebral ischemic injury. Increased GPR120 expression was observed in microglia and neurons following MCAO-induced ischemia in wild type C57BL/6 mice. Treatment with docosahexaenoic acid (DHA) inhibited OGD-induced inflammatory response in primary microglia and murine microglial BV2 cells, whereas silencing of GPR120 strongly exacerbated the inflammation induced by OGD and abolished the anti-inflammatory effects of DHA. Mechanistically, DHA inhibited OGD-induced inflammation through GPR120 interacting with β-arrestin2. In addition to its anti-inflammatory function, GPR120 also played a role in apoptosis as its knockdown impaired the antiapoptotic effect of DHA in OGD-induced rat pheochromocytoma (PC12) cells. Finally, using MCAO mouse model, we demonstrated that GPR120 activation protected against focal cerebral ischemic injury by preventing inflammation and apoptosis. Our study indicated that pharmacological targeting of GPR120 may provide a novel approach for the treatment of patients with ischemic stroke.
Immune-checkpoint inhibitors (ICI) targeting programmed cell death 1 (PD-1) and its ligand 1 (PD-L1) have quickly changed the treatment landscape in advanced non-small cell lung cancer. However, any ...patient treated with an immune checkpoint inhibitor is at risk for immune-related adverse events (irAEs). Checkpoint inhibitor pneumonitis (CIP) is a rare but potentially severe pulmonary toxicity of immunotherapy. Since the imaging features and symptoms are not specific, the diagnosis of CIP is challenging. In addition, CIP may mimic other lung diseases. Due to these characteristics, proper patient management may be delayed. So, a comprehensive understanding of imaging features is essential for a prompt detection and correct management of these drug-induced lung diseases. We presented a patient with lung squamous cell cancer who has clinical symptoms preceding imaging evidence of pneumonitis after immunotherapy and radiotherapy. We also discussed the safety of immunotherapy, the complexity and management of immune pneumonitis.
Ongoing studies have determined that the gut microbiota is a major factor influencing both health and disease. Host genetic factors and environmental factors contribute to differences in gut ...microbiota composition and function. Intestinal dysbiosis is a cause or a contributory cause for diseases in multiple body systems, ranging from the digestive system to the immune, cardiovascular, respiratory, and even nervous system. Investigation of pathogenesis has identified specific species or strains, bacterial genes, and metabolites that play roles in certain diseases and represent potential drug targets. As research progresses, gut microbiome–based diagnosis and therapy are proposed and applied, which might lead to considerable progress in precision medicine. We further discuss the limitations of current studies and potential solutions.
Optical chaos is vital for various applications such as private communication, encryption, anti-interference sensing, and reinforcement learning. Chaotic microcombs have emerged as promising sources ...for generating massive optical chaos. However, their inter-channel correlation behavior remains elusive, limiting their potential for on-chip parallel chaotic systems with high throughput. In this study, we present massively parallel chaos based on chaotic microcombs and high-nonlinearity AlGaAsOI platforms. We demonstrate the feasibility of generating parallel chaotic signals with inter-channel correlation <0.04 and a high random number generation rate of 3.84 Tbps. We further show the application of our approach by demonstrating a 15-channel integrated random bit generator with a 20 Gbps channel rate using silicon photonic chips. Additionally, we achieved a scalable decision-making accelerator for up to 256-armed bandit problems. Our work opens new possibilities for chaos-based information processing systems using integrated photonics, and potentially can revolutionize the current architecture of communication, sensing and computations.
•SIRT1, SIRT2 and PXR genes in Mugilogobius chulae were firstly cloned.•Environmental realistic APAP affected the PXR signaling pathway in M. chulae.•The response of the PXR signaling pathway was ...sensitive to APAP exposure.•The PXR signaling pathway is regulated by SIRTs in M. chulae.
Paracetamol (APAP) is one of the most widely used non-steroidal anti-inflammatory drugs, which is frequently detected in various water bodies. Studies are limited about its toxic effects and mechanisms on non-target aquatic organisms. In this study, an estuarine bottom-dwelling fish named Mugilogobius chulae, distributed in southern China, was selected as experimental species and the changes of PXR signaling pathway, a key signaling pathway of detoxification metabolic system in liver, were investigated under APAP exposure (0.5 μg·L−1, 5 μg·L−1, 50 μg·L−1 and 500 μg·L−1) for 24 h, 72 h and 168 h. Results showed that the key genes (e.g., P-gp, MRP1, CYP1A, CYP3A, GST and SULT) and the enzymatic activities of GST, EROD and ERND in PXR signaling pathway were induced to meet the requirements of detoxification metabolism. By up-regulating the expression of GCLC gene, the reductive small molecule GSH can be rapidly synthesized to counteract the attack of free radicals produced by APAP exposure. The expressions of SIRT1 and SIRT2 proteins decreased, while the expressions of most genes in PXR signaling pathway increased. It was speculated that the expression of PXR and its downstream target genes may be regulated epigenetically by SIRT1 and SIRT2. Studies showed that the exposure to environmental relevant concentrations of APAP can affect the detoxification metabolism of non-target organisms such as Mugilogobius chulae.
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