67 research outputs found

    c-Lysozyme promotes proliferation of chicken embryonic fibroblast through bFGF pathway

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    The egg white (EW) contains the majority of bioactive components which maintain embryo growth and differentiation. The discovery of new growth promoting factor in egg white will provide vital clue to understand the developmental regulation of early chicken embryo. The egg white heated with different temperatures (63.5, 70 and 95°C) underwent testing on its growth-promoting effect on chicken fibroblast in vitro. The purified c-lysozyme and the expression of related genes in basic fibroblast growth factor (bFGF) pathway were analyzed to ascertain its growth-promoting mechanism. 13 h after egg white treatment, more fibroblast synchronized with serum starvation transited into S phrase from G0/G1 in EW group than in the control group (CM) and reached the phase of peak proliferation at 15 h after treatment. It was found that c-lysozyme had the function of promoting cells growth and was decided by gradient heat inactivation of egg white. The addition of more than 0.25 mg/ml c-lysozyme produced significant increase in the cellular proliferation during 48 to 72 h of culture. At 13 h after c-lysozyme treatment, the bFGF, cyclin D, cyclin A and CDK2 were up-regulated significantly and promoted the transition from G0/G1 into S phrase and the accurate completion of S phrase. C-Lysozyme contains a growth-activating domain to promote the cell proliferation besides its anti-microbe domain.Key words: c-Lysozyme, fibroblast, fibroblast growth factor receptor (FGFR), cell cycle

    Efficacy and safety of novel oral anticoagulants versus vitamin K antagonists in the treatment of venous thromboembolism

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    The aim of this meta-analysis was to systematically evaluate the efficacy and safety of novel oral anticoagulants and vitamin K antagonists in the treatment of venous thromboembolism. A total of 6 studies met the inclusion criteria and a total of 19,350 patients with venous thromboembolism were included. Among them, rivaroxaban (3 RCTs, n=90/3,449/4,832); dabigatran (2 RCTs, n=200/2,539); edoxaban (1 RCT, n=8,240). The results of meta-analysis showed that the total bleeding rate after treatment with the vitamin K antagonist group was higher than with the new oral anticoagulant group (OR=0.82, 95% confidence interval 0.75-0.90, p<0.0001), and the difference was highly statistically significant. Overall, new oral anticoagulants are compara-ble to vitamin K antagonists, but new oral anticoagulants can reduce the occurrence of bleeding events and the safety was superior to vitamin K antagonists

    An improved positioning algorithm in a long-range asymmetric perimeter security system

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    In this paper, an improved positioning algorithm is proposed for a long-range asymmetric perimeter security system. This algorithm employs zero-crossing rate to detect the disturbance starting point, and then utilizes an improved empirical mode decomposition to obtain the effective time-frequency distribution of the extracted signal. In the end, a cross-correlation is used to estimate the time delay of the effective extracted signal. The scheme is also verified and analyzed experimentally. The field test results demonstrate that the proposed scheme can achieve a detection of 96.60% of positioning errors distributed within the range of 0-±20 m at the sensing length of 75 km, which significantly improves the positioning accuracy for the long-range asymmetric fence perimeter application

    Sub-second periodic radio oscillations in a microquasar

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    Powerful relativistic jets are one of the ubiquitous features of accreting black holes in all scales. GRS 1915+105 is a well-known fast-spinning black-hole X-ray binary with a relativistic jet, termed as a ``microquasar'', as indicated by its superluminal motion of radio emission. It exhibits persistent x-ray activity over the last 30 years, with quasi-periodic oscillations of 110\sim 1-10 Hz and 34 and 67 Hz in the x-ray band. These oscillations likely originate in the inner accretion disk, but other origins have been considered. Radio observations found variable light curves with quasi-periodic flares or oscillations with periods of 2050\sim 20-50 minutes. Here we report two instances of \sim5 Hz transient periodic oscillation features from the source detected in the 1.05-1.45 GHz radio band that occurred in January 2021 and June 2022, respectively. Circular polarization was also observed during the oscillation phase.Comment: The author version of the article which will appear in Nature on 26 July 2023, 32 pages including the extended data. The online publication version can be found at the following URL: https://www.nature.com/articles/s41586-023-06336-

    Numerical Simulation and PIV Experimental Investigation on Underwater Autorotating Rotor

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    In this work, the flow field of an autorotating rotor in a water tunnel with various pitches and shaft backward angles was investigated via particle image velocimetry (PIV). The experiments were carried out on a free-rotating two-bladed single rotor. Computational Fluid Dynamics (CFD) based on moving overset grids were developed to study the hydrodynamic characteristics of an underwater autorotating rotor. The simulation results are in good agreement with the test results. The thrust and thrust coefficient of the underwater autorotating rotor were calculated by CFD simulation under different situations. The research demonstrates that rotational speed and thrust have a significant positive correlation with water velocity, pitch, and shaft back angle. In particular, the thrust coefficient scarcely varies with the shaft backward angle. An underwater autorotation rotor with a thin airfoil, negative torque, and a suitable number of blades can increase the thrust and thrust coefficient. The investigation is of significance in enriching the autorotation theory of rotors and helping to develop underwater autorotating rotors
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