24 research outputs found

    Suppression of blow-up in 3-D Keller-Segel model via Couette flow in whole space

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    In this paper, we study the 3-D parabolic-parabolic and parabolic-elliptic Keller-Segel models with Couette flow in R3\mathbb{R}^3. We prove that the blow-up phenomenon of solution can be suppressed by enhanced dissipation of large Couette flows. Here we develop Green's function method to describe the enhanced dissipation via a more precise space-time structure and obtain the global existence together with pointwise estimates of the solutions. The result of this paper shows that the enhanced dissipation exists for all frequencies in the case of whole space and it is reason that we obtain global existence for 3-D Keller-Segel models here. It is totally different from the case with the periodic spatial variable xx in [2,10]. This paper provides a new methodology to capture dissipation enhancement and also a surprising result which shows a totally new mechanism.Comment: 22 pag

    Bifurcation on boundary data for linear broadwell model with conservative boundary condition

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    10.1142/S0219891614500179Journal of Hyperbolic Differential Equations113603-61

    Experimental Study on the Axial Tensile Properties of FRP Grid-Reinforced ECC Composites

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    The axial tensile properties of FRP mesh-reinforced ECC composites (TRE) were investigated experimentally under the consideration of four influencing factors: grid type, number of reinforcement layers, ECC matrix thickness, and sticky sand treatment on the grid surface. The test results showed that the axial stiffness and tensile strength of the composite were significantly increased, and the tensile properties were significantly improved under the effect of FRP grid reinforcement. Increasing the thickness of the ECC matrix can obviously improve the crack resistance of composites. The ultimate tensile strength of FRP lattice-reinforced ECC composites increased significantly with the increase in the number of lattice layers, but had no significant effect on the crack resistance. The tensile properties of CFRP grid-reinforced ECC composites were slightly better compared to BFRP grid-reinforced ECC composites. The crack resistance and ultimate tensile strength of the composites were slightly improved by impregnating the surface of the FRP grid with adhesive-bonded sand treatment. Based on the experimental data, the tensile stress–strain constitutive model of FRP grid-reinforced ECC composites is established. The calculation results show that the theoretical values of the model agree well with the experimental values. Therefore, it can be used to reflect the stress–strain change state of FRP lattice-reinforced ECC composites during axial tension

    MiRNA-494 induces trophoblast senescence by targeting SIRT1

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    Objective Although the mechanism underlying preeclampsia (PE) has been widely explored, the mechanisms related to senescence have not yet been fully revealed. Therefore, we investigated the role of the miR-494/longevity protein Sirtuin 1 (SIRT1) axis in PE. Methods Human placental tissue was obtained from severe preeclampsia (SPE) (n = 20) and gestational age-matched normotensive pregnancies (n = 20), and senescence-associated β-galactosidase (SAβG) and SIRT1 expression levels were measured. The TargetScan and miRDB databases predicted candidate miRNAs targeting SIRT1, and intersected with differentially expressed miRNAs in the GSE15789 dataset (p < 0.05, |log2FC|≥1.5). Subsequently, we showed that miRNA (miR)-494 expression was significantly elevated in SPE, revealing miR-494 as a candidate SIRT1-binding miRNA. A dual-luciferase assay confirmed the targeting relationship between miR-494 and SIRT1. The senescence phenotype, migration, cell viability, reactive oxygen species (ROS) production levels and inflammatory molecule expression levels were measured after miR-494 expression was altered. We conducted a rescue experiment using SIRT1 plasmids to further demonstrate the regulatory relationship. Results SIRT1 expression was lower(p < 0.01) and miR-494 expression was higher (p < 0.001) in SPE, and SaβG staining showed premature placental aging in SPE (p < 0.001). Dual-luciferase reporter assays revealed that miR-494 targeted SIRT1. Compared to control cells, HTR-8/SVneo cells with upregulation of miR-494 had remarkably downregulated SIRT1 expression (p < 0.001), more SAβG-positive cells (p < 0.001), cell cycle arrested (p < 0.05), and upregulated P21 and P16 expression (p < 0.01). miR-494 overexpression also decreased HTR-8/SVneo cell migration (p < 0.05) and ATP synthesis (p < 0.001), increased ROS levels (p < 0.001), and upregulated NLRP3 and IL-1β expression (p < 0.01). SIRT1-overexpressing plasmids partially reversed the effects of miR-494 overexpression in HTR-8/SVneo cells. Conclusion The miR-494/SIRT1 interaction plays a role in the mechanism of premature placental aging in PE patients

    Synthesis and Characterization of [60]Fullerene-Poly(glycidyl nitrate) and Its Thermal Decomposition

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    A new energetic fullerene derivative [60]­fullerene-poly­(glycidyl nitrate) (C<sub>60</sub>-PGN) was synthesized through a modified Bingel reaction of C<sub>60</sub> and bromomalonic acid PGN ester in the presence of amino acid and dimethyl sulfoxide. The obtained product was characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy. Results confirmed that C<sub>60</sub>-PGN was synthesized successfully. The thermal decomposition analysis of C<sub>60</sub>-PGN was investigated by differential scanning calorimetry and thermogravimetric analysis with infrared spectroscopy, which revealed that C<sub>60</sub>-PGN exhibits good resistance to thermal decomposition up to 200 °C. The kinetic parameters of the thermal decomposition of C<sub>60</sub>-PGN were also obtained from the differential thermal analysis data by Kissinger and Ozawa–Doyle methods, with <i>E</i><sub>a</sub> = 170.85 and 168.29 kJ·mol<sup>–1</sup>, respectively. C<sub>60</sub>-PGN exhibits stability higher than that of any other known polynitrofullerenes

    Genome-Wide Association Analysis Identified Variants Associated with Body Measurement and Reproduction Traits in Shaziling Pigs

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    With the increasing popularity of genomic sequencing, breeders pay more attention to identifying the crucial molecular markers and quantitative trait loci for improving the body size and reproduction traits that could affect the production efficiency of pig-breeding enterprises. Nevertheless, for the Shaziling pig, a well-known indigenous breed in China, the relationship between phenotypes and their corresponding genetic architecture remains largely unknown. Herein, in the Shaziling population, a total of 190 samples were genotyped using the Geneseek Porcine 50K SNP Chip, obtaining 41857 SNPs for further analysis. For phenotypes, two body measurement traits and four reproduction traits in the first parity from the 190 Shaziling sows were measured and recorded, respectively. Subsequently, a genome-wide association study (GWAS) between the SNPs and the six phenotypes was performed. The correlation between body size and reproduction phenotypes was not statistically significant. A total of 31 SNPs were found to be associated with body length (BL), chest circumference (CC), number of healthy births (NHB), and number of stillborns (NSB). Gene annotation for those candidate SNPs identified 18 functional genes, such as GLP1R, NFYA, NANOG, COX7A2, BMPR1B, FOXP1, SLC29A1, CNTNAP4, and KIT, which exert important roles in skeletal morphogenesis, chondrogenesis, obesity, and embryonic and fetal development. These findings are helpful to better understand the genetic mechanism for body size and reproduction phenotypes, while the phenotype-associated SNPs could be used as the molecular markers for the pig breeding programs

    Integrated models of blood protein and metabolite enhance the diagnostic accuracy for Non-Small Cell Lung Cancer

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    Abstract Background For early screening and diagnosis of non-small cell lung cancer (NSCLC), a robust model based on plasma proteomics and metabolomics is required for accurate and accessible non-invasive detection. Here we aim to combine TMT-LC-MS/MS and machine-learning algorithms to establish models with high specificity and sensitivity, and summarize a generalized model building scheme. Methods TMT-LC-MS/MS was used to discover the differentially expressed proteins (DEPs) in the plasma of NSCLC patients. Plasma proteomics-guided metabolites were selected for clinical evaluation in 110 NSCLC patients who were going to receive therapies, 108 benign pulmonary diseases (BPD) patients, and 100 healthy controls (HC). The data were randomly split into training set and test set in a ratio of 80:20. Three supervised learning algorithms were applied to the training set for models fitting. The best performance models were evaluated with the test data set. Results Differential plasma proteomics and metabolic pathways analyses revealed that the majority of DEPs in NSCLC were enriched in the pathways of complement and coagulation cascades, cholesterol and bile acids metabolism. Moreover, 10 DEPs, 14 amino acids, 15 bile acids, as well as 6 classic tumor biomarkers in blood were quantified using clinically validated assays. Finally, we obtained a high-performance screening model using logistic regression algorithm with AUC of 0.96, sensitivity of 92%, and specificity of 89%, and a diagnostic model with AUC of 0.871, sensitivity of 86%, and specificity of 78%. In the test set, the screening model achieved accuracy of 90%, sensitivity of 91%, and specificity of 90%, and the diagnostic model achieved accuracy of 82%, sensitivity of 77%, and specificity of 86%. Conclusions Integrated analysis of DEPs, amino acid, and bile acid features based on plasma proteomics-guided metabolite profiling, together with classical tumor biomarkers, provided a much more accurate detection model for screening and differential diagnosis of NSCLC. In addition, this new mathematical modeling based on plasma proteomics-guided metabolite profiling will be used for evaluation of therapeutic efficacy and long-term recurrence prediction of NSCLC
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