411 research outputs found

    Research on the characteristics of dynamic behavior of basilar membrane in spiral cochlea

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    This paper used PATRAN software to establish a three-dimensional spiral cochlear model according to the actual human ears, combined with NASTRAN software to conduct a harmonic response analysis on it and studied the impact of curvature on the amplitude of basilar membrane when spiral basilar membrane was excited. The computational result of the model was consistent with the experimental result reported by previous researchers, which verified the correctness of the model established by this paper. Research found the change rule of ratio of outer radius amplitude to inner radius amplitude in the longitudinal direction of basilar membrane and the change trend of the horizontal amplitude with frequency along the basilar membrane. At high frequencies, it was found that curvature had a great influence on the horizontal amplitude of basilar membrane. In the meanwhile, the structural form of spiral basilar membrane and its change trend with frequency at the position of 12 mm reflected the basilar membrane’s amplification for sound intensity. Regarding the controversial issue in the academic at present, does travelling wave exist in basilar membrane? The theory of travelling wave in basilar membrane was supported by a lot of phase accumulation and delay as shown in phase diagram

    Inhibition of miR-182 represses growth of hepatocellular carcinoma cells by targeting SOX11

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    Purpose: To investigate the effect of microRNA-182 (miR-182) on hepatocellular carcinoma (HCC) and its mechanisms of action.Methods: Sixty-five HCC tissues and matched adjacent tissues were obtained, and miR-182 and sexdetermining region on the Y Chromosome (SRY)-related HMG box 11 (SOX11) expression were quantified using reverse transcription-polymerase chain reaction (RT-PCR). SOX11-positive cells were identified by immunohistochemistry and the correlation between SOX11 and miR-182 expression was analyzed by Spearman correlation analysis. Huh-7 cells were transfected with the miR-182 mimic, the miR-182 inhibitor, and/or si-SOX11, and cell proliferation was measured by cell counting kit-8 (CCK-8) assay. Apoptosis was assessed by flow cytometry. Luciferase reporter assay was used to investigate the putative target gene of miR-182. A xenograft nude mouse model was established by transfection  with miR-182 antagomir, while tumor volume and weight were calculated. SOX11, cleaved caspase-3, cleaved poly (ADP ribose) polymerase (PARP), B-cell lymphoma-2 (Bcl-2), and Bcl-2-associated X (Bax) protein levels were analyzed by western blot.Results: MiR-182 expression increased and SOX11 expression was decreased in HCC tissues (p < 0.05). Luciferase reporter assay data confirmed that miR-182 directly targets SOX11. Inhibition of miR-182 repressed proliferation and Bcl-2 expression, but increased protein expression of cleaved caspase-3, cleaved RAPP, and Bax in Huh-7 cells (p < 0.05). In addition, suppression of SOX11 reversed the effects of miR-182 on cell proliferation and apoptosis. The miR-182 antagomir decreased tumor growth and miR-182 expression but increased SOX11 expression in vivo (p < 0.05).Conclusion: MiR-182 and SOX11 may be novel therapeutic targets for HCC patients

    Intestinal acetic acid regulates the synthesis of sex pheromones in captive giant pandas

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    As a typical solitary animal, adult giant pandas rely on chemical signals (sex pheromones) to transmit reproductive information during oestrous. Although researchers have confirmed that the gut microbiota is related to the emission and reception of sex pheromones, there is no clear correlation between the gut microbes and the synthesis of sex pheromone of giant pandas, that is, which gut microbes and microbial metabolites are participate in the synthesis of giant panda’s sex pheromone. As a mirror of gut microbiota, fecal microbiota can reflect the composition of gut microbiota and its interaction with host to some extent. The purpose of this study is to explore how the gut microbes affect the synthesis of sex pheromones in captive giant pandas by combining analysis of the fecal microbiome and metabolomics. The results of correlation and microbial function analysis show that intestinal microorganisms such as Veillonellaceae and Lactobacillilaceae are associated with the synthesis of short chain fatty acid (acetic acid) and volatile ester metabolites, such as 1-butanol, 3-methyl, acetate, acetic acid, hexyl ester and 3-hexen-1-ol, acetate, (Z). In summary, based on this study, we believe that volatile metabolites such as fecal acetate participate in the process of mate preference of captive giant pandas and affect their expression of natural mating behavior. The possible mechanism is that the gut microbes can promote the synthesis of key chemical signaling substances in perianal glands through mediated intermediate fecal metabolites, thus affecting the normal information exchange between giant pandas individuals. The results of this study have greatly enriched our understanding of gut microbes regulating the synthesis of sex pheromones in giant pandas

    No relationship between the distribution of mast cells and the survival of stage IIIB colon cancer patients

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    <p>Abstract</p> <p>Background</p> <p>Mast cells promote the progression of experimental tumors and might be a valuable therapeutic target. However, the relevant clinical evidence is still controversial. This study analyzed the relationship between the distribution of mast cells and the survival of patients with colon cancer to study whether mast cells contribute to tumor progression.</p> <p>Materials and methods</p> <p>Ninety-three cases of pathologically confirmed primary cancer tissues matched with adjacent normal mucosa, metastases of regional-draining lymph nodes and regional-draining lymph nodes without metastases were collected from stage IIIB colon carcinoma patients between January 1997 and July 2004 at the Cancer Center of Sun Yat-Sen University. Tryptase-positive mast cells were counted. The relationships of the distribution of mast cells with clinicopathologic parameters and 5-year survival were analyzed.</p> <p>Results</p> <p>Although the mast cell count in the mucosa adjacent to the primary colon cancer was significantly higher than that in the stroma of the primary colon cancer, no difference in mast cell counts was observed between the stroma in lymph node metastasis and the lymph tissue adjacent to the metastasis. Additionally, the mast cell count in the regional-draining lymph node without the invasion of cancer cells was significantly higher than that in the stroma of lymph node metastasis and adjacent lymph tissue. However, none of those mast cell counts was related to 5-year survival.</p> <p>Conclusion</p> <p>Although mast cell count varied with location, none of the mast cell counts was related to 5-year survival, suggesting that mast cells do not contribute to the progression of stage IIIB colon cancer.</p

    Linking nutrient strategies with plant size along a grazing gradient: Evidence from Leymus chinensis in a natural pasture

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    AbstractStudying the changes in nutrient use strategies induced by grazing can provide insight into the process of grassland degradation and is important for improving grassland quality and enhancing ecosystem function. Dominant species in meadow steppe can optimize their use of limiting resources; however, the regulation of nutrient use strategies across grazing gradients is not fully understood. Therefore, in this study, we report an in situ study in which the impact of grazing rates on nutrient use strategies of Leymus chinensis, the dominant plant species in eastern Eurasian temperate steppes, was investigated. We conducted a large randomized controlled experiment (conducted continuously for five years in grassland plots in a natural pasture in Hailar, eastern Mongolia Plateau, China) to assess the effects of grazing rate treatments (0.00, 0.23, 0.34, 0.46, 0.69, and 0.92 adult cattle unit (AU) ha−1) on L. chinensis along a grazing gradient and employed a random sampling approach to compare the accumulation, allocation, and stoichiometry of C, N, and P in leaves and stems. Our findings demonstrated the follows: (i) The height of L. chinensis decreased with an increase in the grazing gradient, and the concentrations of C, N, and P significantly increased; (ii) the accumulation of C, N, and P per individual was negatively correlated with the concentration of aboveground tissues, suggesting that there was a tradeoff in L. chinensis between nutrient accumulation and concentration at the individual scale; (iii) the leaf-to-stem ratio of C, N, and P accumulation increased with grazing intensity, indicating a tradeoff in nutrient allocation and plant size at the individual plant level; and (iv) grazing rates were negatively correlated with the ratios of C:N and C:P in the stem; however, these ratios in leaves significantly increased with grazing intensity. Our findings suggest that L. chinensis in meadow steppe adapts to grazing disturbance through tradeoffs between plant size and nutrient use strategies. Moreover, our results imply that grazing produces a compensatory effect on nutrient use efficiency between the stems and leaves of L. chinensis

    Bostrycin inhibits proliferation of human lung carcinoma A549 cells via downregulation of the PI3K/Akt pathway

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    <p>Abstract</p> <p>Background</p> <p>Bostrycin is a novel compound isolated from marine fungi that inhibits proliferation of many cancer cells. However, the inhibitory effect of bostrycin on lung cancers has not been reported. This study is to investigate the inhibitory effects and mechanism of bostrycin on human lung cancer cells in vitro.</p> <p>Methods</p> <p>We used MTT assay, flow cytometry, microarray, real time PCR, and Western blotting to detect the effect of bostrycin on A549 human pulmonary adenocarcinoma cells.</p> <p>Results</p> <p>We showed a significant inhibition of cell proliferation and induction of apoptosis in bostrycin-treated lung adenocarcinoma cells. Bostrycin treatment caused cell cycle arrest in the G0/G1 phase. We also found the upregulation of microRNA-638 and microRNA-923 in bostrycin-treated cells. further, we found the downregulation of p110α and p-Akt/PKB proteins and increased activity of p27 protein after bostrycin treatment in A549 cells.</p> <p>Conclusions</p> <p>Our study indicated that bostrycin had a significant inhibitory effect on proliferation of A549 cells. It is possible that upregulation of microRNA-638 and microRNA-923 and downregulaton of the PI3K/AKT pathway proteins played a role in induction of cell cycle arrest and apoptosis in bostrycin-treated cells.</p

    Physiological responses and transcriptome analyses of upland rice following exposure to arsenite and arsenate

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    Acknowledgements This research was financially supported by the National Natural Science Foundation of China (No.41471274) and the Scottish Government’s Rural and Environment Science and Analytical Service Division (RESAS).Peer reviewedPostprin
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