695 research outputs found

    On a New Weighted Hilbert Inequality

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    It is shown that a weighted Hilbert inequality for double series can be established by introducing a proper weight function. Thus, a quite sharp result of the classical Hilbert inequality for double series is obtained. And a similar result for the Hilbert integral inequality is also proved. Some applications are considered

    Split private and shared L2 cache architecture for snooping-based CMP

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    California, US

    Expression of endo-1, 4-beta-xylanase from Trichoderma reesei in Pichia pastoris and functional characterization of the produced enzyme

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    <p>Abstract</p> <p>Background</p> <p>In recent years, xylanases have attracted considerable research interest because of their potential in various industrial applications. The yeast <it>Pichia pastoris </it>can neither utilize nor degrade xylan, but it possesses many attributes that render it an attractive host for the expression and production of industrial enzymes.</p> <p>Results</p> <p>The Xyn2 gene, which encodes the main <it>Trichoderma reesei </it>Rut C-30 endo-β-1, 4-xylanase was cloned into the pPICZαA vector and expressed in <it>Pichia pastoris</it>. The selected <it>P. pastoris </it>strains produced as 4,350 nkat/ml β-xylanase under the control of the methanol inducible alcohol oxidase 1 (<it>AOX1</it>) promoter. The secreted recombinant Xyn2 was estimated by SDS-PAGE to be 21 kDa. The activity of the recombinant Xyn2 was highest at 60°C and it was active over a broad range of pH (3.0–8.0) with maximal activity at pH 6.0. The enzyme was quite stable at 50°C and retained more than 94% of its activity after 30 mins incubation at this temperature. Using Birchwood xylan, the determined apparent <it>K</it><sub>m </sub>and k<sub>cat </sub>values were 2.1 mg/ml and 219.2 S<sup>-1</sup>, respectively. The enzyme was highly specific towards xylan and analysis of xylan hydrolysis products confirmed as expected that the enzyme functions as endo-xylanase with xylotriose as the main hydrolysis products. The produced xylanase was practically free of cellulolytic activity.</p> <p>Conclusion</p> <p>The <it>P. pastoris </it>expression system allows a high level expression of xylanases. Xylanase was the main protein species in the culture supernatant, and the functional tests indicated that even the non-purified enzyme shows highly specific xylanase activity that is free of cellulolytic side acitivities. Therefore, <it>P pastoris </it>is a very useful expression system when the goal is highly specific and large scale production of glycosyl hydrolases.</p

    State Estimation of Wireless Sensor Networks in the Presence of Data Packet Drops and Non-Gaussian Noise

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    Distributed Kalman filter approaches based on the maximum correntropy criterion have recently demonstrated superior state estimation performance to that of conventional distributed Kalman filters for wireless sensor networks in the presence of non-Gaussian impulsive noise. However, these algorithms currently fail to take account of data packet drops. The present work addresses this issue by proposing a distributed maximum correntropy Kalman filter that accounts for data packet drops (i.e., the DMCKF-DPD algorithm). The effectiveness and feasibility of the algorithm are verified by simulations conducted in a wireless sensor network with intermittent observations due to data packet drops under a non-Gaussian noise environment. Moreover, the computational complexity of the DMCKF-DPD algorithm is demonstrated to be moderate compared with that of a conventional distributed Kalman filter, and we provide a sufficient condition to ensure the convergence of the proposed algorithm

    Development of a Sensitive Phospho-p70 S6 Kinase ELISA to Quantify mTOR Proliferation Signal Inhibition

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    Background: Drug blood levels can only serve as a surrogate because of the lack of information on the drug's direct pharmacological effects in the individual patient. Measurement of the mammalian target of rapamycin (mTOR) activity dependent on the phosphorylation status of p70 S6 kinase (p70 S6K) offers a practical way for monitoring pharmacodynamic drug activity, with the potential to better assess the state of immunosuppression in individual patients. Material and Methods: Here, we established a novel in vitro model system by treating Jurkat cells and peripheral blood mononuclear cells with different concentrations of sirolimus after stimulation with phorbol 12-myristate 13-acetate. Results: A dose-dependent reduction of the p70 S6K phosphorylation status was demonstrated by Western blot and a newly established enzyme-linked immunosorbent assay (ELISA). Relative phospho-p70 S6K values from ELISA and relative densities from Western blot analysis in peripheral blood mononuclear cells revealed a strong correlation (Spearman correlation coefficient r(s) = 0.7, P = 0.01). Finally, parallel assays confirmed a sirolimus dose-dependent reduction of cytokine production and cell proliferation in the in vitro model. Conclusions: Pharmacodynamic monitoring of mTOR inhibition with a p70 S6K ELISA could guide mTOR inhibitor immunosuppression therapy toward a more individualized therapy. The usage of this technique now has to be evaluated in a clinical series of patients

    Distributed fusion filter over lossy wireless sensor networks with the presence of non-Gaussian noise

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    The information transmission between nodes in a wireless sensor networks (WSNs) often causes packet loss due to denial-of-service (DoS) attack, energy limitations, and environmental factors, and the information that is successfully transmitted can also be contaminated by non-Gaussian noise. The presence of these two factors poses a challenge for distributed state estimation (DSE) over WSNs. In this paper, a generalized packet drop model is proposed to describe the packet loss phenomenon caused by DoS attacks and other factors. Moreover, a modified maximum correntropy Kalman filter is given, and it is extended to distributed form (DM-MCKF). In addition, a distributed modified maximum correntropy Kalman filter incorporating the generalized data packet drop (DM-MCKF-DPD) algorithm is provided to implement DSE with the presence of both non-Gaussian noise pollution and packet drop. A sufficient condition to ensure the convergence of the fixed-point iterative process of the DM-MCKF-DPD algorithm is presented and the computational complexity of the DM-MCKF-DPD algorithm is analyzed. Finally, the effectiveness and feasibility of the proposed algorithms are verified by simulations
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