109 research outputs found

    Chaotic dynamics in Bertrand model with technological innovation

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    In this paper, the dynamics of a Bertrand duopoly game with technology innovation have been studied, which contains boundedly rational and naive players. They have been analyzed that the stability of the equilibrium point, the bifurcation and chaotic behavior of the dynamic system. It has been proved that technology innovation has played a very important role in the stability of Nash equilibrium point. Technology innovation can enlarge the stability region of the speed and control the chaos of the dynamic system effectively

    Alteration in the sensitivity to crizotinib by Na+/H+ exchanger regulatory factor 1 is dependent to its subcellular localization in ALK-positive lung cancers

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    BackgroundNa+/H+ exchanger regulatory factor 1 (NHERF1) is an important scaffold protein participates in the modulation of a variety of intracellular signal pathways. NHERF1 was able to enhance the effects of chemo-drugs in breast and cervical cancer cells. Anaplastic lymphoma kinase (ALK) fusion mutations are validated molecules targeted therapy in lung cancers, where crizotinib can be used as the specific inhibitor to suppress tumor progression. However, due to the less frequent occurrence of ALK mutations and the complexity for factors to determine drug responses, the genes that could alter crizotinib sensitivity are unclear.MethodsBoth ALK-translocated and ALK-negative lung adenocarcinoma specimens in tissue sections were collected for immunohistochemistry. The possible mechanisms of NHERF1 and its role in the cell sensitivity to crizotinib were investigated using an ALK-positive and crizotinib-sensitive lung adenocarcinoma cell line H3122. Either a NHERF1 overexpression vector or agents for NHERF1 knockdown was used for crizotinib sensitivity measures, in association with cell viability and apoptosis assays.ResultsThe expression level of NHERF1 in ALK-translocated NSCLC was significantly higher than that in other lung cancer tissues. NHERF1 expression in ALK positive lung cancer cells was regulated by ALK activities, and was in return able to alter the sensitivity to crizotinib. The function of NHERF1 to influence crizotinib sensitivity was depending on its subcellular distribution in cytosol instead of its nucleus localized form.ConclusionEctopically overexpressed NHERF1 could be a functional protein for consideration to suppress lung cancers. The determination of NHERF1 levels in ALK positive NSCLC tissues might be useful to predict crizotinib resistance, especially by distinguishing cytosolic or nuclear localized NHERF1 for the overexpressed molecules

    TransRender: a transformer-based boundary rendering segmentation network for stroke lesions

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    Vision transformer architectures attract widespread interest due to their robust representation capabilities of global features. Transformer-based methods as the encoder achieve superior performance compared to convolutional neural networks and other popular networks in many segmentation tasks for medical images. Due to the complex structure of the brain and the approximate grayscale of healthy tissue and lesions, lesion segmentation suffers from over-smooth boundaries or inaccurate segmentation. Existing methods, including the transformer, utilize stacked convolutional layers as the decoder to uniformly treat each pixel as a grid, which is convenient for feature computation. However, they often neglect the high-frequency features of the boundary and focus excessively on the region features. We propose an effective method for lesion boundary rendering called TransRender, which adaptively selects a series of important points to compute the boundary features in a point-based rendering way. The transformer-based method is selected to capture global information during the encoding stage. Several renders efficiently map the encoded features of different levels to the original spatial resolution by combining global and local features. Furthermore, the point-based function is employed to supervise the render module generating points, so that TransRender can continuously refine the uncertainty region. We conducted substantial experiments on different stroke lesion segmentation datasets to prove the efficiency of TransRender. Several evaluation metrics illustrate that our method can automatically segment the stroke lesion with relatively high accuracy and low calculation complexity

    SHADE AVOIDANCE 4 is required for proper auxin distribution in the hypocotyl

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    The phytohormone auxin is involved in virtually every aspect of plant growth and development. Through polar auxin transport, auxin gradients can be established, which then direct plant differentiation and growth. Shade avoidance responses are well- known processes that require polar auxin transport. In this study, we have identified a mutant, shade avoidance 4 (sav4), defective in shade-induced hypocotyl elongation and basipetal auxin transport. SAV4 encodes an unknown protein with armadillo repeat- and tetratricopeptide repeat-like domains known to provide protein-protein interaction surfaces. C terminally yellow fluorescent protein-tagged SAV4 localizes to both the plasma membrane and the nucleus. Membrane-localized SAV4 displays a polar association with the shootward plasma membrane domain in hypocotyl and root cells, which appears to be necessary for its function in hypocotyl elongation. Cotransfection of SAV4 and ATP-binding cassette B1 (ABCB1) auxin transporter in tobacco (Nicotiana benthamiana) revealed that SAV4 blocks ABCB1-mediated auxin efflux. We thus propose that polarly localized SAV4 acts to inhibit ABCB-mediated auxin efflux toward shoots and facilitates the establishment of proper auxin gradients

    Elevated first-trimester hepcidin level is associated with reduced risk of iron deficiency anemia in late pregnancy: a prospective cohort study

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    BackgroundIron deficiency (ID) and iron deficiency anemia (IDA) during pregnancy are highly prevalent worldwide. Hepcidin is considered an important biomarker of iron status. Currently, few longitudinal cohort studies have assessed the potential causal relationship between hepcidin and ID/IDA. Therefore, we aimed to investigate the association of first-trimester maternal serum hepcidin with third-trimester ID/IDA risk in a prospective cohort.MethodsTotal of 353 non-ID/IDA pregnant women at 11–13 weeks’ gestation were enrolled in Southern China and followed up to 38 weeks of gestation. Data on demography and anthropometry were obtained from a structured questionnaire at enrollment. Iron biomarkers including hepcidin were measured at enrollment and follow-up. Regression models were used to evaluate the association of first-trimester hepcidin with third-trimester ID/IDA risk.ResultsSerum hepcidin levels substantially decreased from 19.39 ng/mL in the first trimester to 1.32 ng/mL in the third trimester. Incidences of third-trimester ID and IDA were 46.2 and 11.4%, respectively. Moreover, moderate and high levels of first-trimester hepcidin were positively related to third-trimester hepcidin (log-transformed β = 0.51; 95% CI = 0.01, 1.00 and log-transformed β = 0.66; 95% CI = 0.15, 1.17). Importantly, elevated first-trimester hepcidin was significantly associated with reduced risk of third-trimester IDA (OR = 0.38; 95% CI = 0.15, 0.99), but not with ID after adjustment with potential confounders.ConclusionFirst-trimester hepcidin was negatively associated with IDA risk in late pregnancy, indicating higher first-trimester hepcidin level may predict reduced risk for developing IDA. Nonetheless, given the limited sample size, larger studies are still needed

    Leukadherin-1-Mediated Activation of CD11b Inhibits LPS-Induced Pro-inflammatory Response in Macrophages and Protects Mice Against Endotoxic Shock by Blocking LPS-TLR4 Interaction

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    Dysregulation of macrophage has been demonstrated to contribute to aberrant immune responses and inflammatory diseases. CD11b, expressed on macrophages, plays a critical role in regulating pathogen recognition, phagocytosis, and cell survival. In the present study, we explored the effect of leukadherin-1 (LA1), an agonist of CD11b, on regulating LPS-induced pro-inflammatory response in macrophages and endotoxic shock. Intriguingly, we found that LA1 could significantly reduce mortalities of mice and alleviated pathological injury of liver and lung in endotoxic shock. In vivo studies showed that LA1-induced activation of CD11b significantly inhibited the LPS-induced pro-inflammatory response in macrophages of mice. Moreover, LA1-induced activation of CD11b significantly inhibited LPS/IFN-γ-induced pro-inflammatory response in macrophages by inhibiting MAPKs and NF-κB signaling pathways in vitro. Furthermore, the mice injected with LA1-treated BMDMs showed fewer pathological lesions than those injected with vehicle-treated BMDMs in endotoxic shock. In addition, we found that activation of TLR4 by LPS could endocytose CD11b and activation of CD11b by LA1 could endocytose TLR4 in vitro and in vivo, subsequently blocking the binding of LPS with TLR4. Based on these findings, we concluded that LA1-induced activation of CD11b negatively regulates LPS-induced pro-inflammatory response in macrophages and subsequently protects mice from endotoxin shock by partially blocking LPS-TLR4 interaction. Our study provides a new insight into the role of CD11b in the pathogenesis of inflammatory diseases

    Equilibrium stability of dynamic duopoly Cournot game under heterogeneous strategies, asymmetric information, and one-way R&D spillovers

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    Bounded rationality, asymmetric information, and R&D spillovers are widely existed in monopoly markets, and they have been researched separately by a large number of literatures; however, there are few works that discussed both R&D spillovers and asymmetric information in oligopolistic games with bounded rational firms. Considering that R&D spillovers only flow from the R&D leader to the R&D follower, a duopoly Cournot game with heterogeneous expectations and asymmetric information is presented. In our model, a firm with private information of his marginal cost is designed, and the coefficient of R&D spillovers is introduced. Interesting findings show the following: (i) In a static duopoly Cournot game with perfect rationality, the equilibrium output of firm 1 with private information is negatively related to R&D spillovers and the probability of high marginal cost, while firm 2’s equilibrium output is positively correlated with them. (ii) In a dynamic duopoly Cournot game with asymmetric information and heterogeneous expectations, if firms adopt adaptive expectation and naïve expectation respectively, the Nash equilibrium is always globally asymptotically stable; if they use adaptive expectation and gradient dynamical expectation respectively, the Nash equilibrium tends to be locally asymptotically stable under certain conditions. Furthermore, the bigger the probability of high marginal cost or R&D spillovers are, the more volatile the monopoly market is, while higher technology innovation efficiency (TIE) of firm 1 is conducive to the stability of the product market. Our study would have theoretical and practical significance to the technological innovation activities of homogeneous products in oligopoly markets

    The Influencing Factors and Promotion Countermeasures of Industrial Generic Technology Diffusion Based on Differential Game

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    Many factors affect the diffusion of generic technology due to the variety of generic technology and the multiplicity of diffusion carriers. Therefore, it is very urgent to determine the main factors that influence generic technology diffusion. Based on theories of industrial generic technology diffusion, this paper constructs a differential game-based model between government and enterprises. Then, this study explores the key factors that affect the diffusion strategy of industrial generic technology innovation and analyzes the possible method for improving industrial generic technology innovation diffusion. The following conclusions are obtained. Incentive measures, rewards, and penalties play a key role in the diffusion of generic technology, and the costs and benefits incurred by the diffusion are critical to the diffusion of generic technology. Also, the net income of enterprises has a positive impact on the adoption of generic technology diffusion. After that, this paper carries out data simulation for result verification and provides some policy implications
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