440 research outputs found

    Nash's Existence Theorem for Non-compact Strategy Sets

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    This paper generalizes the Fan-Knaster-Kuratowski-Mazurkiewicz (FKKM) lemma to the case of weak topology, and obtains the Ky Fan minimax inequality defined on non-empty non-compact convex subsets in reflexive Banach spaces, then we apply it to game theory and obtain Nash's existence theorem for non-compact strategy sets, together with John von Neumann's existence theorem in two-player zero-sum games.Comment: 8 page

    INVESTIGATION OF HYDROELASTIC BEHAVIOR OF A PONTOON-TYPE VLFS DURING UNSTEADY EXTERNAL LOADS IN WAVE CONDITION USING A HYBRID FINITE ELEMENT-BOUNDARY ELEMENT (FE-ME) METHOD

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    The hydroelastic behaviour of a pontoon-type VLFS subjected to unsteady external loads in wave condition is investigated in the context of the time-domain modal expansion theory, in which the boundary element method (BEM) based on time domain Kelvin sources is used for hydrodynamic forces and the finite element method (FEM) is adopted for solving the deflections of the VLFS. In this analysis, the interpolation-tabulation scheme is applied to assess rapidly and accurately the free-surface Green function in finite water depth, and the boundary integral equation of a quarter VLFS model is further established taking advantage of symmetry of flow field and structure. The VLFS is modelled as an equivalent solid plate based on the Mindlin plate theory. The coupled plate-water model is performed to determine the wave-induced responses and transient behaviour under external loads such as a huge mass impact onto the structure and moving loads of an airplane, respectively. These results are verified with existing numerical results and experimental test. Then, the developed numerical tools are used in the study of the combined action taking into account of the mass drop/airplane landing as well as forward or reverse incident wave action. The deflections of the runway, the time history of vertical positions and the trajectory of the airplane are also presented through a systematic time-domain simulation, which illustrates the usefulness of the presently developed numerical solutions

    MiR-138 ameliorates myocardial ischemia/reperfusion injury by targeting intercellular cell adhesion molecule 1

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    Purpose: To explore the effect of miR-138 on regulating intercellular cell adhesion molecule 1 (ICAM-1) expression in endothelial cells to alleviate cardiac ischemia/reperfusion (I/R) injury and its related mechanisms. Methods: The left anterior descending artery of the heart was occluded for 30 min and then perfused for 2 h to induce a rat model of cardiac I/R injury. H9C2 cells were cultured in an anoxic medium without serum to establish the model of hypoxia/reoxygenation (H/R). Triphenyl tetrazolium chloride (TTC) staining was applied to measure myocardial infarction sizes in rat hearts. The mRNA expression levels of miR-138 and ICAM-1 were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Dual luciferase reporter assay was used to identify the target of miR-138. The agomiR-138 and miR-138 mimics were transfected into H9C2 cells; exogenous ICAM-1 was also administered, and ROS accumulation, cell viability, and apoptosis were measured. Furthermore, the underlying mechanism was investigated. Results: MiR-138 was downregulated both in vitro and in vivo. AgomiR-138 reduced myocardial infarction area, decreased ROS production and suppressed cell apoptosis in a rat model of cardiac I/R injury. On the other hand, miR-138 mimics increased cell viability, enhanced ROS production and induced cell apoptosis in H/R-induced H9C2 cells. Further analysis verified ICAM-1 as a target of miR- 138. Besides, exogenous ICAM-1 inhibited the protective effect of miR-138 on H/R-induced apoptosis in vitro. Conclusion: MiR-138 may protect against injury of myocardial I/R by targeting ICAM-1. The results also provide insight into miR-138/ICAM-1 axis as new therapeutic targets for myocardial I/R injury. Keywords: Intercellular cell adhesion molecule 1, MicroRNA-138, Myocardial/ischemia reperfusion injury, Reactive oxygen specie

    Preparation of Attapulgite Loaded Nano Zero Valent Iron Material and Its Adsorption of Silver

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    In the extensive industrial production process, a large amount of silver containing wastewater has been produced, and the veil of its potential harm has gradually been unveiled. The emission standards of various pollutants formulated and issued by the Ministry of Ecology and Environment of China have already strictly limited the emission limits of silver. In this paper, a simple, environment-friendly and inexpensive method was used to synthesize a composite material with reducing and adsorbing effects on silver by using purified attapulgite and ferrous salt (FeSO4·7H2O) as raw materials, potassium borohydride (KBH4) as reducing agent, and chemical liquid phase reduction method. The experimental results showed that under the conditions of 1:1 ratio of iron to soil, 0.25 mol·L-1 concentration of KBH4, 25 C temperature and 120 min time, the synthesized attapulgite loaded nano-zero-valent iron composite (nZVI/ATP) had good adsorption performance for Ag(I)

    An Operational Statistical Scheme for Tropical Cyclone-Induced Rainfall Forecast

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    Nonparametric methods are used in this study to analyze and predict short-term rainfall due to tropical cyclones (TCs) in a coastal meteorological station. All 427 TCs during 1953–2011, which made landfall along the Southeast China coast with a distance less than 700 km to a certain meteorological station, Shenzhen, are analyzed and grouped according to their landfalling direction, distance, and intensity. The corresponding daily rainfall records at Shenzhen Meteorological Station (SMS) during TCs landfalling period (a couple of days before and after TC landfall) are collected. The maximum daily rainfall (R24) and maximum 3-day accumulative rainfall (R72) records at SMS for each TC category are analyzed by a nonparametric statistical method, percentile estimation. The results are plotted by statistical boxplot, expressing in the probability of precipitation. The performance of the statistical boxplots was evaluated to forecast the short-term rainfall at SMS during the TC seasons in 2012 and 2013. The results show that the boxplot scheme can be used as a valuable reference to predict the short-term rainfall at SMS due to TCs landfalling along the Southeast China coast
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