203 research outputs found

    Box-counting measure of metric spaces

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    In this paper, we introduce a new notion called the \emph{box-counting measure} of a metric space. We show that for a doubling metric space, an Ahlfors regular measure is always a box-counting measure; consequently, if EE is a self-similar set satisfying the open set condition, then the Hausdorff measure restricted to EE is a box-counting measure. We show two classes of self-affine sets, the generalized Lalley-Gatzouras type self-affine sponges and Bara\'nski carpets, always admit box-counting measures; this also provides a very simple method to calculate the box-dimension of these fractals. Moreover, among others, we show that if two doubling metric spaces admit box-counting measures, then the multi-fractal spectra of the box-counting measures coincide provided the two spaces are Lipschitz equivalent

    Characterization of anti-leukemia components from Indigo naturalis using comprehensive two-dimensional K562/cell membrane chromatography and in silico target identification.

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    Traditional Chinese Medicine (TCM) has been developed for thousands of years and has formed an integrated theoretical system based on a large amount of clinical practice. However, essential ingredients in TCM herbs have not been fully identified, and their precise mechanisms and targets are not elucidated. In this study, a new strategy combining comprehensive two-dimensional K562/cell membrane chromatographic system and in silico target identification was established to characterize active components from Indigo naturalis, a famous TCM herb that has been widely used for the treatment of leukemia in China, and their targets. Three active components, indirubin, tryptanthrin and isorhamnetin, were successfully characterized and their anti-leukemia effects were validated by cell viability and cell apoptosis assays. Isorhamnetin, with undefined cancer related targets, was selected for in silico target identification. Proto-oncogene tyrosine-protein kinase (Src) was identified as its membrane target and the dissociation constant (Kd) between Src and isorhamnetin was 3.81 μM. Furthermore, anti-leukemia effects of isorhamnetin were mediated by Src through inducing G2/M cell cycle arrest. The results demonstrated that the integrated strategy could efficiently characterize active components in TCM and their targets, which may bring a new light for a better understanding of the complex mechanism of herbal medicines

    Evaluation and correction of GPM satellite precipitation products during Typhoon "In-Fa" affecting Zhejiang

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    To understand and improve the performance and quality of Global Precipitation Measurement (GPM) satellite-derived precipitation products during the typhoon process, with gauge observations from ground meteorological stations, this study used the successive and optimal interpolation correction methods to correct the GPM precipitation products. The performance of GPM products (Version 6) before and after the correction at different time scales are evaluated with the products during the two landfalls of Typhon"In-Fa". Results show that the original GPM precipitation products fail to describe the strong rainfall center over the high terrain area, which significantly underestimates the precipitation by approximately 45%. This is mainly due to the underestimation of the large values in the northeast region of Zhejiang province. The analysis of precipitation classification inspection suggests that the uncorrected GPM satellite-derived products have good capability for light rain, but poor for other rainfall levels. After the successive and optimal interpolation correction, significant improvement can be found in the cumulative, daily, and hourly rainfall products. The products with successive correction are better, while the product with optimal interpolation slightly overestimates the actual precipitation. The corrected GPM products can not only describe the heavy precipitation center related to the terrain but also reflect heavy rainstorms and heavy precipitation with hourly rainfall intensity greater than 23 mm·h-1

    Visible-Light Degradation of Dyes and Phenols over Mesoporous Titania Prepared by Using Anthocyanin from Red Radish as Template

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    Heterogeneous photocatalysis is able to operate effectively to eliminate organic compounds from wastewater in the presence of semiconductor photocatalyst and a light source. Although photosensitization of titania by organic dyes is one of the conventional ways for visible-light utilization of titania, previous studies have not yet addressed the use of natural food coloring agents as templates in the synthesis of mesostructured materials, let alone the simultaneous achievement of highly crystalline mesoscopic framework and visible-light photocatalytic activity. In this work, anthocyanin, a natural pigment from red radish was directly used as template in synthesis of highly crystalline mesoporous titania. The synthesized mesoporous titania samples were characterized by a combination of various physicochemical techniques, such as XRD, SEM, HRTEM, nitrogen adsorption/desorption, and diffuse reflectance UV-Vis. The prepared mesoporous titania photocatalyst exhibited significant activity under visible-light irradiation for the degradation of dyes and phenols due to its red shift of band-gap-absorption onset and visible-light response as a result of the incorporation of surface carbon species

    Asynchronous multi-rate method of real-time simulation for active distribution networks

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    The real-time simulation of active distribution networks (ADNs) can provide an accurate insight into transient behaviours, but faces challenges in simulation efficiency and flexibility brought by larger system scales and wider time-scale ranges. This paper presents an asynchronous multi-rate (AMR) method and design for the real-time simulation of large-scale ADNs. In the proposed method, the entire ADN was decoupled into different subsystems according to accuracy requirements, and optimized time-steps were allocated to each subsystem to realize a fully distributed simulation. This not only alleviated the time-step coordination problem existing in multi-rate real-time simulations, but also enhanced the flexible expansion capabilities of the real-time simulator. To realize the AMR real-time simulation, a multi-rate interfacing method, synchronization mechanism, and data communication strategy are proposed in this paper, and their hardware design is also presented in detail. A modified IEEE 123-node system with photovoltaics and wind turbine generators was simulated on a 3 field-programmable gate arrays (FPGAs)-based AMR real-time simulator. The real-time results were captured by the oscilloscope and verified with PSCAD/EMTDC, which demonstrated the superiority in simulation flexibility and accuracy compared with the synchronous multi-rate (SMR) method

    Nadir CA-125 level as prognosis indicator of high-grade serous ovarian cancer

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    PURPOSE: The capacity of nadir CA-125 levels to predict the prognosis of epithelial ovarian cancer remains controversial. This study aimed to explore whether the nadir CA-125 serum levels could predict the durations of overall survival (OS) and progression free survival (PFS) in patients with high-grade serous ovarian cancer (HG-SOC) from the USA and PRC. MATERIALS AND METHODS: A total of 616 HG-SOC patients from the MD Anderson Cancer Center (MDACC, USA) between 1990 and 2011 were retrospectively analyzed. The results of 262 cases from the Jiangsu Institute of Cancer Research (JICR, PRC) between 1992 and 2011 were used to validate the MDACC data. The CA-125 immunohistochemistry assay was performed on 280 tissue specimens. The Cox proportional hazards model and the log-rank test were used to assess the associations between the clinicopathological characteristics and duration of survival. RESULTS: The nadir CA-125 level was an independent predictor of OS and PFS (p < 0.01 for both) in the MDACC patients. Lower nadir CA-125 levels (≤10 U/mL) were associated with longer OS and PFS (median: 61.2 and 16.8 months with 95% CI: 52.0–72.4 and 14.0–19.6 months, respectively) than their counterparts with shorter OS and PFS (median: 49.2 and 10.5 months with 95% CI: 41.7–56.7 and 6.9–14.1 months, respectively). The nadir CA-125 levels in JICR patients were similarly independent when predicting the OS and PFS (p < 0.01 for both). Nadir CA-125 levels less than or equal to 10 U/mL were associated with longer OS and PFS (median: 59.9 and 15.5 months with 95% CI: 49.7–70.1 and 10.6–20.4 months, respectively), as compared with those more than 10 U/mL (median: 42.0 and 9.0 months with 95% CI: 34.4–49.7 and 6.6–11.2 months, respectively). Baseline serum CA-125 levels, but not the CA-125 expression in tissues, were associated with the OS and PFS of HG-SOC patients in the MDACC and JICR groups. However, these values were not independent. Nadir CA-125 levels were not associated with the tumor burden based on second-look surgery (p = 0.09). Patients who achieved a pathologic complete response had longer OS and PFS (median: 73.7 and 20.7 months with 95% CI: 63.7–83.7 and 9.5–31.9 months, respectively) than those with residual tumors (median: 34.6 and 10.6 months with 95% CI: 6.9–62.3 and 4.9–16.3 months, respectively). CONCLUSIONS: The nadir CA-125 level was an independent predictor of OS and PFS in HG-SOC patients. Further prospective studies are required to clinically optimize the chances for a complete clinical response of HG-SOC cases with higher CA-125 levels (>10 U/mL) at the end of primary treatment

    Pyrotinib and chrysin synergistically potentiate autophagy in HER2-positive breast cancer

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    Human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) has been the most challenging subtype of BC, consisting of 20% of BC with an apparent correlation with poor prognosis. Despite that pyrotinib, a new HER2 inhibitor, has led to dramatic improvements in prognosis, the efficacy of pyrotinib monotherapy remains largely restricted due to its acquired resistance. Therefore, identifying a new potential antitumor drug in combination with pyrotinib to amplify therapeutic efficacy is a pressing necessity. Here, we reported a novel combination of pyrotinib with chrysin and explored its antitumor efficacy and the underlying mechanism in HER2-positive BC. We determined that pyrotinib combined with chrysin yielded a potent synergistic effect to induce more evident cell cycle arrest, inhibit the proliferation of BT-474 and SK-BR-3 BC cells, and repress in vivo tumor growth in xenograft mice models. This may be attributed to enhanced autophagy induced by endoplasmic reticulum stress. Furthermore, the combined treatment of pyrotinib and chrysin induced ubiquitination and glucose-6-phosphate dehydrogenase (G6PD) degradation by upregulating zinc finger and BTB/POZ domain-containing family protein 16 (ZBTB16) in tumorigenesis of BC. Mechanistically, we identified that miR-16-5p was a potential upstream regulator of ZBTB16, and it showed a significant inverse correlation with ZBTB16. Inhibition of miR-16-5p overexpression by restoring ZBTB16 significantly potentiated the overall antitumor efficacy of pyrotinib combined with chrysin against HER2-positive BC. Together, these findings demonstrate that the combined treatment of pyrotinib and chrysin enhances autophagy in HER2-positive BC through an unrecognized miR-16-5p/ZBTB16/G6PD axis.</p
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