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This article introduces a particular weak Galerkin (WG) element on rectangular/cuboid partitions that uses k$$ k $$th order polynomial for weak finite element functions and (k+1)$$ \left(k+1\right) $$th order polynomials for weak derivatives. This WG element is highly accurate with convergence two orders higher than the optimal order in an energy norm and the L2$$ {L}^2 $$ norm. The superconvergence is verified analytically and numerically. Furthermore, the usual stabilizer in the standard weak Galerkin formulation is no longer needed for this element. [ABSTRACT FROM AUTHOR]

Additives and antibiotic abuse during food production and processing are among the key factors affecting food safety. The efficient and rapid detection of hazardous substances in food is of crucial relevance to ensure food safety. In this study, a water-soluble quantum dot with glutathione as a ligand was synthesized as a fluorescent probe by hydrothermal method to achieve the detection and analysis of H2O2. The detection limits were 0.61 μM in water and 68 μM in milk. Meanwhile, it was used as a fluorescent donor probe and manganese dioxide nanosheets were used as a fluorescent acceptor probe in combination with an immunoassay platform to achieve the rapid detection and analysis of enrofloxacin (ENR) in a variety of foods with detection limits of 0.05–0.25 ng/mL in foods. The proposed systems provided new ideas for the construction of fluorescence sensors with high sensitivity. [ABSTRACT FROM AUTHOR]

Cancer patients who receive radiotherapy have a high risk of severe acute respiratory syndrome‐coronavirus‐2 (SARS‐CoV‐2) infection, but the concrete reason remains unclear. Herein, we investigated the influence of irradiation on the vulnerability of cancer cells to SARS‐CoV‐2 using S pseudovirions and probed the underlying mechanism via RNA‐seq and other molecular biology techniques. Owing to the enhancement of sphingolipid metabolism, irradiation accelerated pseudovirion infection. Mechanistically, irradiation induced the expression of acid sphingomyelinase (ASM), which catalyses the hydrolysis of sphingomyelin to ceramide, contributing to lipid raft formation and promoting SARS‐CoV‐2 invasion. Inhibition of lipid raft formation with methyl‐β‐cyclodextrin (MβCD) or the tyrosine kinase inhibitor genistein and ASM suppression through small interfering RNA or amitriptyline (AMT) treatment abolished the enhancing effect of irradiation on viral infection. Animal experiments supported the finding that irradiation promoted SARS‐CoV‐2 S pseudovirion infection in A549 cell tumour‐bearing BALB/c nude mice, whereas AMT treatment dramatically decreased viral infection. This study discloses the role of sphingolipid metabolism in irradiation‐induced SARS‐CoV‐2 infection, thus providing a potential target for clinical intervention to protect patients receiving radiotherapy from COVID‐19. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the molecular regulatory mechanism of 1-methylcyclopropene (1-MCP) treatment on leaf yellowing of pak choi during storage at 20 °C. In the present study, compared with the control and 10 μL/L ethylene-treated pak choi, 5.0 μL/L 1-MCP fumigation alleviated the yellowing process of pak choi as proved by the maintenance of higher levels of colour, chlorophyll content, and appearance. 1-MCP treatment decreased chlorophyll breakdown by downregulating the activity of chlorophyll-degrading enzymes (chlorophyll b reductase (CBR) and pheophytinase (PPH)) and the expression of their related genes (BcNYC1 and BcPPH). The application of 1-MCP also inhibited the transcript abundance of ethylene biosynthesis and signal transduction genes (BcACO , BcEIN3, and BcERF) and reduced ethylene production, thus helping to maintain the green colour of pak choi; however, ethylene treatment exerted the opposite function. Meanwhile, three transcription factors (BcNAC055, BcMYB44, and BcOBF1) were successfully cloned. Experiments performed using yeast one-hybrid assay, dual-luciferase reporter system and in vivo bioluminescence imaging assay, confirmed that BcNAC055, BcMYB44, and BcOBF1 directly bound to the BcNYC1 promoter. 1-MCP inhibited the expression levels of BcNAC055, BcMYB44, BcOBF1, and BcNYC1 during storage, while the application of ethylene activated their expression. In conclusion, 1-MCP downregulated the expression of the key chlorophyll degradation gene BcNYC1 by inhibiting the transcript level of its three positive regulators (BcNAC055, BcMYB44, and BcOBF1) and lowered the activity of chlorophyll-degrading enzyme CBR, thereby helping mitigate chlorophyll breakdown to retard leaf yellowing in pak choi. The results of this work extend our understanding of 1-MCP-delayed yellowing in postharvest pak choi. [ABSTRACT FROM AUTHOR]

Studies have shown the indicative role of handgrip strength in health. However, there is limited evidence revealing its potential effect on death events among middle-aged and older adults in China. We aimed to prospectively evaluate if lower handgrip strength is associated with the event of death. Among 17,167 middle-aged and older adults between age 45 to 96, handgrip strength was collected by a handheld dynamometer in a Chinese longitudinal study of aging trend (CHARLS) 2011–2018. Using Cox proportional hazard models with exposures, we assessed the association between handgrip strength and death events. Elevated handgrip strength values were independently associated with the decreased death risk. These results illustrate that lower handgrip strength is an independent indicator of death risks among middle-aged and older Chinese, which highlights the significance of related intercessions. The median values of five levels of handgrip strength in the entire cohort were 16.5,23,28,33,42kg at baseline. A linear association existed between the handgrip strength values and the risk of all-cause death within 34.2kg. Handgrip strength can serve as an independent indicator for death risks. [ABSTRACT FROM AUTHOR]

This article presents a |$P_0$| finite element method for boundary value problems for linear elasticity equations. The new method makes use of piecewise constant approximating functions on the boundary of each polytopal element and is devised by simplifying and modifying the weak Galerkin finite element method based on |$P_1/P_0$| approximations for the displacement. This new scheme includes a tangential stability term on top of the simplified weak Galerkin to ensure the necessary stability due to the rigid motion. The new method involves a small number of unknowns on each element, it is user friendly in computer implementation and the element stiffness matrix can be easily computed for general polytopal elements. The numerical method is of second-order accurate, locking-free in the nearly incompressible limit, and ease polytopal partitions in practical computation. Error estimates in |$H^1$|⁠ , |$L^2$| and some negative norms are established for the corresponding numerical displacement. Numerical results are reported for several two-dimensional and three-dimensional test problems, including the classical benchmark Cook's membrane problem in two dimensions as well as some three-dimensional problems involving shear-loaded phenomena. The numerical results show clearly the simplicity, stability, accuracy and efficiency of the new method. [ABSTRACT FROM AUTHOR]

Myelosuppression is a common and intractable side effect of cancer therapies including radiotherapy and chemotherapy, while the underlying mechanism remains incompletely understood. Here, using a mouse model of radiotherapy-induced myelosuppression, we show that inorganic phosphate (Pi) metabolism is acutely inhibited in hematopoietic stem cells (HSCs) during irradiation-induced myelosuppression, and closely correlated with the severity and prognosis of myelosuppression. Mechanistically, the acute Pi metabolic inhibition in HSCs results from extrinsic Pi loss in the bone marrow niche and the intrinsic transcriptional suppression of soluble carrier family 20 member 1 (SLC20A1)-mediated Pi uptake by p53. Meanwhile, Pi metabolic inhibition blunts irradiation-induced Akt hyperactivation in HSCs, thereby weakening its ability to counteract p53-mediated Pi metabolic inhibition and the apoptosis of HSCs and consequently contributing to myelosuppression progression. Conversely, the modulation of the Pi metabolism in HSCs via a high Pi diet or renal Klotho deficiency protects against irradiation-induced myelosuppression. These findings reveal that Pi metabolism and HSC survival are causally linked by the Akt/p53–SLC20A1 axis during myelosuppression and provide valuable insights into the pathogenesis and management of myelosuppression. [ABSTRACT FROM AUTHOR]