60 research outputs found

    Verrucisidinol and Verrucosidinol Acetate, Two Pyrone-Type Polyketides Isolated from a Marine Derived Fungus, Penicillium aurantiogriseum

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    The new secondary metabolites verrucosidinol (1) and its derivative verrucosidinol acetate (2), together with a potent neurotoxin verrucosidin (3), a congener norverrucosidin (4) and a mixture of two known phytotoxic metabolites terrestric acids (5 and 6), were isolated from the marine derived fungus Penicillium aurantiogriseum. Verrucosidinol has a ring-opened ethylene oxide moiety in the polyene α-pyrone skeleton, and verrucosidinol acetate is its acetate derivative. The chemical structures were determined by comparing with literature data and a combination of spectroscopic techniques, including high resolution mass spectrum and two-dimentional nuclear magnetic resonance spectroscopic analysis

    Mast Cells Modulate Acute Toxoplasmosis in Murine Models

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    The role of mast cells (MCs) in Toxoplasma gondii infection is poorly known. Kunming outbred mice were infected intraperitoneally with RH strain T. gondii, either treated with compound 48/80 (C48/80, MC activator) or disodium cromoglycate (DSCG, MC inhibitor). Compared with infected controls, infected mice treated with C48/80 exhibited significantly increased inflammation in the liver (P \u3c 0.01), spleen (P \u3c 0.05), and mesentery (P \u3c 0.05) tissues, higher parasite burden in the peritoneal lavage fluids (P \u3c 0.01), and increased levels of mRNA transcripts of T. gondii tachyzoite surface antigen 1 (SAG1) gene in the spleen and liver tissues (P \u3c 0.01), accompanied with significantly increased Th1 cytokine (IFN-γ, IL-12p40, and TNF-α) (P \u3c 0.01) and decreased IL-10 (P \u3c 0.01) mRNA expressions in the liver, and increased IFN-γ (P \u3c 0.01) and IL-12p40 (P \u3c 0.01) but decreased TNF-α (P \u3c 0.01) and IL-4 (P \u3c 0.01) in the spleens of infected mice treated with C48/80 at day 9-10 p.i. Whereas mice treated with DSCG had significantly decreased tissue lesions (P \u3c 0.01), lower parasite burden in the peritoneal lavage fluids (P \u3c 0.01) and decreased SAG1 expressions in the spleen and liver tissues (P \u3c 0.01), accompanied with significantly increased IFN-γ (P \u3c 0.01) and IL-12p40 (P \u3c 0.05) in the liver, and decreased IFN-γ (P \u3c 0.05) and TNF-α (P \u3c 0.01) in the spleens; IL-4 and IL-10 expressions in both the spleen and liver were significantly increased (P \u3c 0.01) in the infected mice treated with DSCG. These findings suggest that mediators associated with the MC activation may play an important role in modulating acute inflammatory pathogenesis and parasite clearance during T. gondii infection in this strain of mice. Thus, MC activation/inhibition mechanisms are potential novel targets for the prevention and control of T. gondii infection

    A High-Order Discontinuous Galerkin Method for Solving Preconditioned Euler Equations

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    A high-order discontinuous Galerkin (DG) method is presented for solving the preconditioned Euler equations with an explicit or implicit time marching scheme. A detailed description is given of a practical implementation of a precondition matrix of the type of Weiss and Smith and of the DG spatial discretization scheme employed, with particular emphasis on the artificial viscosity-based shock capturing techniques. The curved boundary treatment is proposed through adopting a NURBS surface equipped with a radial basis function interpolation to propagate the boundary displacement to the interior of the mesh. The resulting methods are verified by simulating flows over two-dimensional airfoils, such as symmetric NACA0012 or asymmetric RAE2822, and over three-dimensional bodies, such as an academic hemispherical headform or aerodynamic ONERA M6 wing. Numerical results show that the present method functions for both transonic and nearly incompressible flow simulations, and the proposed treatment of curved boundaries, play an important role in improving the accuracy of the obtained solutions, which are in good agreement with available experimental data or other numerical solutions reported in literature

    Fast and Constrained Absent Keyphrase Generation by Prompt-Based Learning

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    Generating absent keyphrases, which do not appear in the input document, is challenging in the keyphrase prediction task. Most previous works treat the problem as an autoregressive sequence-to-sequence generation task, which demonstrates promising results for generating grammatically correct and fluent absent keyphrases. However, such an end-to-end process with a complete data-driven manner is unconstrained, which is prone to generate keyphrases inconsistent with the input document. In addition, the existing autoregressive decoding method makes the generation of keyphrases must be done from left to right, leading to slow speed during inference. In this paper, we propose a constrained absent keyphrase generation method in a prompt-based learning fashion. Specifically, the prompt will be created firstly based on the keywords, which are defined as the overlapping words between absent keyphrase and document. Then, a mask-predict decoder is used to complete the absent keyphrase on the constraint of prompt. Experiments on keyphrase generation benchmarks have demonstrated the effectiveness of our approach. In addition, we evaluate the performance of constrained absent keyphrases generation from an information retrieval perspective. The result shows that our approach can generate more consistent keyphrases, which can improve document retrieval performance. What’s more, with a non-autoregressive decoding manner, our model can speed up the absent keyphrase generation by 8.67× compared with the autoregressive method

    Influence of perceived stress on executive function: the path of self-hate and negative affect in adolescents

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    BackgroundThe development of executive function in adolescents is influenced by many environmental factors. Previous studies have found that perceived stress is closely related to executive function, whereas its role in the mediation of executive function remains poorly studied.ObjectiveTo explore the role of negative affect and self-hate in mediating the relationship between perceived stress and executive function in adolescents, so as to assist the improvement of executive function in adolescents.MethodsQuestionnaires were administered to 7 734 adolescents from five junior and five senior high schools in Rizhao city, Shandong province from 1 to 30 May 2022. Data were collected using a self-made questionnaire, and adolescents were assessed using Perceived Stress Scale (PSS), Behavior Rating Inventory of Executive Function-Self Report Version (BRIEF-SR), Patient Health Questionnaire (PHQ-4) and Self-Hate Scale (SHS). Spearman correlation analysis was conducted to examine the correlation between variables. A Bootstrap method was chosen to examine the mediation effect of self-hate and negative affect on the relationship between perceived stress and executive function in adolescents.ResultsA total of 7 012 (90.66%) valid questionnaires were retrieved. BRIEF-SR score was positively correlated with PSS, PHQ-4 and SHS scores (r=0.564, 0.653, 0.597, P<0.01). PSS score was positively correlated with PHQ-4 and SHS scores (r=0.615, 0.531, P<0.01). PHQ-4 score was positively correlated with SHS score (r=0.566, P<0.01). The value of mediation effect of perceived stress on executive function was 0.574 (95% CI: 0.555~0.594). Self-hate (indirect effect value of 0.160, 95% CI: 0.145~0.175) and negative affect (indirect effect value of 0.143, 95% CI: 0.129~0.158), separately from each other, mediated the relationship between perceived stress and executive function, and a chained mediation effect of self-hate and negative affect was also documented (indirect effect value of 0.065, 95% CI: 0.058~0.073), accounting for 27.87%, 24.91% and 11.32% of the total effect, respectively.ConclusionThe perceived stress of adolescents may be a influencing factor of the executive function. Additionally, perceived stress can either directly affect executive function or indirectly through the separate or chained mediation via negative affect and self-hate

    Discovery of Anti-MRSA Secondary Metabolites from a Marine-Derived Fungus Aspergillus fumigatus

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    Methicillin-resistant Staphylococcus aureus (MRSA), a WHO high-priority pathogen that can cause great harm to living beings, is a primary cause of death from antibiotic-resistant infections. In the present study, six new compounds, including fumindoline A&ndash;C (1&ndash;3), 12&beta;, 13&beta;-hydroxy-asperfumigatin (4), 2-epi-tryptoquivaline F (17) and penibenzophenone E (37), and thirty-nine known ones were isolated from the marine-derived fungus Aspergillus fumigatus H22. The structures and the absolute configurations of the new compounds were unambiguously assigned by spectroscopic data, mass spectrometry (MS), electronic circular dichroism (ECD) spectroscopic analyses, quantum NMR and ECD calculations, and chemical derivatizations. Bioactivity screening indicated that nearly half of the compounds exhibit antibacterial activity, especially compounds 8 and 11, and 33&ndash;38 showed excellent antimicrobial activities against MRSA, with minimum inhibitory concentration (MIC) values ranging from 1.25 to 2.5 &mu;M. In addition, compound 8 showed moderate inhibitory activity against Mycobacterium bovis (MIC: 25 &mu;M), compound 10 showed moderate inhibitory activity against Candida albicans (MIC: 50 &mu;M), and compound 13 showed strong inhibitory activity against the hatching of a Caenorhabditis elegans egg (IC50: 2.5 &mu;M)

    Downregulation of PPA2 expression correlates with poor prognosis of kidney renal clear cell carcinoma

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    Background Kidney renal clear cell carcinoma (KIRC) is the most common subtype of kidney cancer. Inorganic pyrophosphatase (PPA2) is an enzyme that catalyzes the hydrolysis of pyrophosphate to inorganic phosphate; few studies have reported its significance in cancers. Therefore, we aimed to explore the prognostic value of PPA2 in KIRC. Methods PPA2 expression was detected via immunohistochemistry in a tissue chip containing specimens from 150 patients with KIRC. We evaluated the correlation between PPA2 expression, clinicopathological characteristics, and survival. Data from online databases and another cohort (paraffin-embedded specimens from 10 patients with KIRC) were used for external validation. Results PPA2 expression was significantly lower in KIRC tissues than in normal renal tissues (p < 0.0001). Low expression of PPA2 was significantly associated with a high histologic grade and poor prognosis. The differential expression of PPA2 was validated at the gene and protein levels. Multivariate Cox regression analysis showed that PPA2 expression was an independent prognostic factor in patients with KIRC. Gene set enrichment analysis suggested that decreased expression of PPA2 might be related to the epithelial-mesenchymal transition in KIRC. Conclusions Our study demonstrated that PPA2 is an important energy metabolism-associated biomarker correlated with a favorable prognosis in KIRC

    Mast cells modulate acute toxoplasmosis in murine models.

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    The role of mast cells (MCs) in Toxoplasma gondii infection is poorly known. Kunming outbred mice were infected intraperitoneally with RH strain T. gondii, either treated with compound 48/80 (C48/80, MC activator) or disodium cromoglycate (DSCG, MC inhibitor). Compared with infected controls, infected mice treated with C48/80 exhibited significantly increased inflammation in the liver (P < 0.01), spleen (P < 0.05), and mesentery (P < 0.05) tissues, higher parasite burden in the peritoneal lavage fluids (P < 0.01), and increased levels of mRNA transcripts of T. gondii tachyzoite surface antigen 1 (SAG1) gene in the spleen and liver tissues (P < 0.01), accompanied with significantly increased Th1 cytokine (IFN-γ, IL-12p40, and TNF-α) (P < 0.01) and decreased IL-10 (P < 0.01) mRNA expressions in the liver, and increased IFN-γ (P < 0.01) and IL-12p40 (P < 0.01) but decreased TNF-α (P < 0.01) and IL-4 (P < 0.01) in the spleens of infected mice treated with C48/80 at day 9-10 p.i. Whereas mice treated with DSCG had significantly decreased tissue lesions (P < 0.01), lower parasite burden in the peritoneal lavage fluids (P < 0.01) and decreased SAG1 expressions in the spleen and liver tissues (P < 0.01), accompanied with significantly increased IFN-γ (P < 0.01) and IL-12p40 (P < 0.05) in the liver, and decreased IFN-γ (P < 0.05) and TNF-α (P < 0.01) in the spleens; IL-4 and IL-10 expressions in both the spleen and liver were significantly increased (P < 0.01) in the infected mice treated with DSCG. These findings suggest that mediators associated with the MC activation may play an important role in modulating acute inflammatory pathogenesis and parasite clearance during T. gondii infection in this strain of mice. Thus, MC activation/inhibition mechanisms are potential novel targets for the prevention and control of T. gondii infection
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