1,095 research outputs found

    Para comenzar con una línea hermosa

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    Este es un estudio que se concentra en la búsqueda de una línea hermosa. Comienza con una distinción entre una línea hermosa y una línea apropiada y con una discusión de las tendencias generales de pintores clásicos y modernos en Occidente en relación con este tema. Después de proporcionar esta perspectiva, el autor retoma nuevamente a China y da pruebas de la antigua forma de pensar de este pueblo sobre una línea hermosa. También se incluirá la diferencia entre “caligrafía” y “caligrafía artística”, el dicho “la pintura y la caligrafía com- parten el mismo origen”, la posición de las pinturas arquitectónicas y, como conclusión, la forma china de diferenciar la pintura “verdadera” de aquella “muerta”. Esta es principalmente una discusión de ideas antiguas, pero el autor trata de ponerlas en un contexto contemporáneo y las toma como uno de los puntos claves por los cuales se hace la comparación entre la estética China y la Occidental, con la estética Griega como su origen

    Angiogenic deficiency and adipose tissue dysfunction are associated with macrophage malfunction in SIRT1 \u3csup\u3e-/-\u3c/sup\u3e mice

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    The histone deacetylase sirtuin 1 (SIRT1) inhibits adipocyte differentiation and suppresses inflammation by targeting the transcription factors peroxisome proliferator-activated receptor γ and nuclear factor κB. Although this suggests that adiposity and inflammation should be enhanced when SIRT1 activity is inactivated in the body, this hypothesis has not been tested in SIRT1 null (SIRT1 -/-) mice. In this study, we addressed this issue by investigating the adipose tissue in SIRT1 -/-mice. Compared with their wild-type littermates, SIRT1 null mice exhibited a significant reduction in body weight. In adipose tissue, the average size of adipocytes was smaller, the content of extracellular matrix was lower, adiponectin and leptin were expressed at 60% of normal level, and adipocyte differentiation was reduced. All of these changes were observed with a 50% reduction in capillary density that was determined using a three-dimensional imaging technique. Except for vascular endothelial growth factor, the expression of several angiogenic factors (Pdgf, Hgf, endothelin, apelin, and Tgf-β)was reduced by about 50%. Macrophage infiltration and inflammatory cytokine expression were 70% less in the adipose tissue of null mice and macrophage differentiation was significantly inhibited in SIRT1 -/- mouse embryonic fibroblasts in vitro. In wild-type mice, macrophage deletion led to a reduction in vascular density. These data suggest that SIRT1 controls adipose tissue function through regulation of angiogenesis, whose deficiency is associated with macrophage malfunction in SIRT1 -/- mice. The study supports the concept that inflammation regulates angiogenesis in the adipose tissue. Copyright © 2012 by The Endocrine Society

    Threshold Dynamics of a Huanglongbing Model with Logistic Growth in Periodic Environments

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    We analyze the impact of seasonal activity of psyllid on the dynamics of Huanglongbing (HLB) infection. A new model about HLB transmission with Logistic growth in psyllid insect vectors and periodic coefficients has been investigated. It is shown that the global dynamics are determined by the basic reproduction number R0 which is defined through the spectral radius of a linear integral operator. If R0 1, then the disease persists. Numerical values of parameters of the model are evaluated taken from the literatures. Furthermore, numerical simulations support our analytical conclusions and the sensitive analysis on the basic reproduction number to the changes of average and amplitude values of the recruitment function of citrus are shown. Finally, some useful comments on controlling the transmission of HLB are given

    Novel Wavelet Threshold Denoising Method in Axle Press-Fit Zone Ultrasonic Detection

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    Axles are important part of railway locomotives and vehicles. Periodic ultrasonic inspection of axles can effectively detect and monitor axle fatigue cracks. However, in the axle press-fit zone, the complex interface contact condition reduces the signal-noise ratio (SNR). Therefore, the probability of false positives and false negatives increases. In this work, a novel wavelet threshold function is created to remove noise and suppress press-fit interface echoes in axle ultrasonic defect detection. The exponential threshold function proposed by Andria [1] can\u27t get a gradual curve for later optimum searching process; and the novel wavelet threshold function with two variables is designed to ensure the precision of optimum searching process. Based on the positive correlation between the correlation coefficient and SNR [2] and with the experiment phenomenon that the defect and the press-fit interface echo have different axle-circumferential correlation characteristics, a discrete optimum searching process for two undetermined variables in novel wavelet threshold function is conducted. The performance of the proposed method is assessed by comparing it with traditional threshold methods using real data. The statistic results of the amplitude and the peak SNR of defect echoes show that the proposed wavelet threshold denoising method not only maintains the amplitude of defect echoes but also has a higher peak SNR

    Triptolide ameliorates lipopolysaccharide-induced acute lung injury in rats

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    BACKGROUND: Acute lung injury (ALI) is a serious clinical syndrome with a high rate of mortality. In this study, the effects of triptolide on lipopolysaccharide (LPS)-induced ALI in rats were investigated. METHODS: Sixty-five male Sprague Dawley rats(approved by ethics committee of the First Affiliated Hospital of Soochow University) were randomly divided into five groups. The control group was injected with 2.5 mL saline/kg body weight via the tail vein and intraperitoneally with 1% dimethyl sulfoxide (DMSO) (n = 5). The L group was administered with 0.2% LPS dissolved in saline (5 mg/kg) to induce ALI via the tail vein (n = 15). The TP1, TP2, and TP3 groups were treated as rats in the L group and then intraperitoneally injected with 25, 50, and 100 μg triptolide/kg body weight, respectively (15 rats per group). Blood samples from the left heart artery were taken for blood gas analysis at 1 hour before injection and at 1, 3, 6, and 12 hours after saline and DMSO administration in the control group, LPS injection in the L group, and triptolide injection in the TP1, TP2, and TP3 groups. Lung wet-to-dry weight (W/D) ratio, diffuse alveolar damage (DAD) score, TNF-α levels, and mRNA and protein expression of toll-like receptor 4 (TLR4) were analyzed. RESULTS: Compared with the control group, the arterial partial pressure of oxygen (PaO(2)) declined (P <0.05), the W/D ratio and DAD score increased (P <0.05), and TNF-α levels in serum and bronchoalveolar lavage fluid (BALF) and mRNA and protein expression of TLR4 were significantly increased in the L group (P <0.05). Compared with the L group, PaO(2) significantly increased in the TP2 and TP3 groups (P <0.05), while the W/D ratio and DAD score were significantly decreased in the TP2 and TP3 groups (P <0.05). TNF-α levels and mRNA and protein expression of TLR4 were significantly decreased in the TP2 and TP3 groups compared with the L group (P <0.05). CONCLUSIONS: Triptolide can ameliorate LPS-induced ALI by reducing the release of the inflammatory mediator TNF-α and inhibiting TLR4 expression
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