Image quality metrics for visual optical instruments

The effect of coma and astigmatism on subjective quality of image of sinusoidal and square-bar targets is simulated by using digital processing system. A suprathreshold method is employed in psychophysical discrimination experiments. We determine the robustness of some image quality metrics that can be employed during automated production of visual instruments by examining the correlation between subjective results and objective measures. These include the variance of the wavefront aberration, the Strehl ratio, the radius of 84% encircled energy of the point spread function (R84), the modulation transfer function (MTF) and the integral of the MTF across the frequency range of interest (MTFa). For the target orientation that is most affected by the aberrations, we find that MTFa and R84 give good correlation with subjective result, while the Strehl ratio and the variance do not. In addition, we find that the MTFa correlates with subjective results for all orientations

Swertiamarin attenuates carbon tetrachloride (CCl4)-induced liver injury and inflammation in rats by regulating the TLR4 signaling pathway

The aim of the present study is to illustrate the effects of swertiamarin (STM), a natural iridoid from herbal medicines, on hepatic inflammation induced by carbon tetrachloride (CCl4) in rats. Male Sprague Dawley rats were exposed to CCl4 with or without STM co-administration for 8 weeks. Our results revealed that STM administration (100 and 200 mg/kg b.w.) significantly attenuated inflammation in livers of CCl4-treated rats. STM remarkably reduced the production of interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), macrophage inflammatory protein-1a (MIP1α), and monocyte chemotactic protein-1 (MCP-1) in liver tissue of CCl4-treated rats. In addition, STM treatment downregulated connective tissue growth factor (CTGF) and ser307pIRS-1 expression, which was induced by CCl4 exposure. In the process of exploring the anti-inflammatory mechanisms of STM action, we demonstrated that STM significantly inhibited Toll-like receptor 4 (TLR4) and nuclear factor kappa B (NF-κB) p65 expression in the liver. In conclusion, these results suggested that the inhibition of CCl4-induced inflammation by STM was, at least in part, due to its regulation of the TLR4 /NF-κB signaling pathway

Local Buckling of Concrete Filled Rectangular Steel Tube with Longitudinal Stiffener under Axial Compression

Width-thickness ratio was an important parameter for designing Concrete Filled Rectangular Steel Tube (CFRST). Welding longitudinal stiffener on the internal wall of steel pipe could delay the local buckling, which increased the limit of width-thickness ratio. If there was not enough stiffener and its sectional dimension was too small, the local buckling of steel pipe would occur, inducing its bearing capacity seriously. If the stiffener sectional dimension was too large, concrete filled in steel tube would be broken up, which reduces its bearing capacity. To solve that problem, this paper studied local buckling of CFRST with longitudinal stiffener under axial compression and design of longitudinal stiffener. It established buckling analysis model, simplified local buckling analysis as calculating buckling load of thin plate clamped on loading side and unloading side under axial force. It deduced buckling load and buckling coefficient based on the principle of energy. The results showed that buckling mode depended on stiffening rigidity. Therefore, it put forward minimum stiffening rigidity ratio that controlled the stiffener design. This paper also came up with a formula to calculate minimum stiffening rigidity ratio. It provided guidance on designing number, sectional dimension and material performance

PhysarumSpreader: a new bio-Inspired methodology for identifying influential spreaders in complex networks

Identifying influential spreaders in networks, which contributes to optimizing the use of available resources and efficient spreading of information, is of great theoretical significance and practical value. A random-walk-based algorithm LeaderRank has been shown as an effective and efficient method in recognizing leaders in social network, which even outperforms the well-known PageRank method. As LeaderRank is initially developed for binary directed networks, further extensions should be studied in weighted networks. In this paper, a generalized algorithm PhysarumSpreader is proposed by combining LeaderRank with a positive feedback mechanism inspired from an amoeboid organism called Physarum Polycephalum. By taking edge weights into consideration and adding the positive feedback mechanism, PhysarumSpreader is applicable in both directed and undirected networks with weights. By taking two real networks for examples, the effectiveness of the proposed method is demonstrated by comparing with other standard centrality measures

Research on the Innovation of Business Ecosystem Model in China’s 0nline Food Reservation Market at Sharing Economic Era

At the sharing economy era, the online food reservation market has experienced great changes, such as the mobilization of ordering，cooperation of logistics , diversification of revenue stream. The ordering patterns has also changed from network order to improve user experience. At present, online food reservation market has difficulties inquickly dealing with the impacts and challenges bought by external environment due to lack of coordination and sharing mechanisms and competition over cooperation among economic individuals.Based on the theory of business ecosystem, this paper focuses on the impacts and challenges brought by the sharing economic era and takes “Huijiachifan” as a case study and proposes new framework of business ecosystem model in China\u27s online food reservation market