401 research outputs found

    Resistance imparted by vitamin C, vitamin e and vitamin B12 to the acute hepatic glycogen change in rats caused by noise.

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    The effects of vitamin C, vitamin E and vitamin B12 on the noise-induced acute change in hepatic glycogen content in rats were investigated. The exposure of rats to 95 dB and 110 dB of noise acutely reduced their hepatic glycogens. Vitamin C (ascorbic acid) and vitamin E (alpha -tocopherol) attenuated the noise-inducedacute reduction in the hepatic glycogen contents. This result suggests that antioxidants could reduce the change via reactive oxygen species. Vitamin B12 (cobalamin) delayed the noiseinduced change, a finding that suggests that vitamin B12 could postpone the acute change via compensating for vitamin B12 deficiency

    Research on vehicle handling inverse dynamics based on optimal control while encountering emergency collision avoidance

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    Vehicle driving safety is the urgent key problem to be solved of vehicle independent development while encountering emergency collision avoidance with high speed. And it is also the premise and one of the necessary conditions of vehicle active safety. A new technique for vehicle handling inverse dynamics which can evaluate the emergency collision avoidance performance is proposed. Firstly, the steering angle input of 3-DOF vehicle mode is established. The steering angle input imposed by driver is the control variable, and accurately tracking the expected path was the control object. The optimal control problem can be converted into a nonlinear programming problem while using the state variables conversion, which was solved by the sequential quadratic programming (SQP) algorithm. The results show that vehicle can well track the expected path in high speed

    Vehicle steering wheel angle identification research based on dynamic program method

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    In order to improve the safety of vehicle manipulation as well as to provide a theoretical basis for the study of vehicle steering system and intelligent parking systems, a new method of vehicle steering wheel angle identification is presented – the dynamic program method. First, three freedom degrees of vehicle model is established. Then Bellman’s principle of optimality is used for minimizing the objective function. The dynamic optimization model of the load identification that the yawing angular velocity, lateral acceleration and vehicle body roll angle identified the steering wheel angle and angle velocity. The result shows that the dynamic program method for the steering wheel angle identification problem containing the measurement noise has strong adaptability, high accuracy and good anti-jamming capability

    Research on Sustainable Development of Competitive Sports in China Based on PSR and DEA Model

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    From the 2008 Beijing Olympic Games to the 2022 Beijing Winter Olympics, the sustainable development of competitive sports has become more and more popular in China. Therefore, for the sustainable development of China's competitive sports, first, the logical relationship of “pressure-state-response” is adopted to select the index system, covering the elements of the economy, society, policy, and so on. Principal component analysis and entropy weight method are used to construct the comprehensive evaluation model of the sustainable development of competitive sports. Second, through the coupling coordination method to study the coordinated development of China's competitive sports and economic society, and then from the perspective of the obstacle factor diagnosis method to determine the obstacles to the sustainable development of China's competitive sports system. Finally, the DEA model is used to predict the development level of competitive sports in China's provinces in the next 10–20 years. The research shows that the overall development level of competitive sports in China is good, but there are certain differences among different regions. Meanwhile, from the forecast results, the development level of competitive sports in Hainan, Shanxi, Anhui, Jiangxi, Inner Mongolia, Gansu, and Ningxia may be greatly improved in the future. Based on the above research conclusions, this study puts forward some suggestions to give full play to the joint and synergistic development effect among different regions, reasonably draw lessons from the advanced experience of competitive sports development at home and abroad, and scientifically construct the comprehensive development system of competitive sports. At the same time, the research of this study provides some reference value for the sustainable development of China's competitive sports and the coordinated development of China's competitive sports and economic society

    Vibration performance analysis of vehicle with the non-pneumatic new mechanical elastic wheel in the impulse input experiment

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    A non-pneumatic tire appears to have advantages over the conventional pneumatic tire in terms of flat proof and maintenance free. A mechanical elastic wheel (MEW) with a non-pneumatic elastic outer ring which functions as the air of the pneumatic tire was presented. The structure of MEW is non-inflatable integrated configuration and the effect of hinges is accounted for only in tension. To establish finite element model of MEW, various nonlinear factors, such as the geometrical nonlinearity, material nonlinearity and contact nonlinearity, were considered. Load characteristic test was conducted by tyre dynamic test-bed to obtain force-deflection curves. And the validity of the finite element model was validated through load characteristic test. The vehicle vibration performance respectively based on the MEW and the radial tire was compatative studied under pulse input experiment conditions. The result showed that the vehicle concluding the new mechanical elastic wheel met the vibration performance requirements and vibration performance regularity of pneumatic tire. The results could be used as the thesis reference for the improvement of new mechanical elastic wheel

    Ultrasound-assisted degradation of a new bacterial exopolysaccharide WL-26 from Sphingomonas sp.

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    Ultrasonic degradation of a new exopolysaccharide WL-26 from Sphingomonas sp. was made over the frequency range 200 to 1200 Hz and polymer concentrations of 3, 5, 10 and 20 g/L using high performance anion exchange pulsed-amperometric detection chromatography (HPAEC–PAD) and infrared spectroscopy. Sonication was more efficient with less concentrated polysaccharide solutions, high ultrasonic frequency, long duration of ultrasonic irradiation and degradation continued until a limiting molecular weight was attained. Results show that HPAEC–PAD revealed WL-26 to be an acidic polysaccharide composed of rhamnose, glucose, mannose, galactose and glucuronic acid in the molar ratio of 10:9:3:1:3 distinctly different from welan gum which does not contain galactose.Key words: Exopolysaccharide WL-26, ultrasonic degradation, infrared spectroscopy

    Sequence determinants of human gene regulatory elements

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    Analysis of massively parallel reporter assays measuring the transcriptional activity of DNA sequences indicates that most transcription factor (TF) activity is additive and does not rely on specific TF-TF interactions. Individual TFs can have different gene regulatory activities. DNA can determine where and when genes are expressed, but the full set of sequence determinants that control gene expression is unknown. Here, we measured the transcriptional activity of DNA sequences that represent an similar to 100 times larger sequence space than the human genome using massively parallel reporter assays (MPRAs). Machine learning models revealed that transcription factors (TFs) generally act in an additive manner with weak grammar and that most enhancers increase expression from a promoter by a mechanism that does not appear to involve specific TF-TF interactions. The enhancers themselves can be classified into three types: classical, closed chromatin and chromatin dependent. We also show that few TFs are strongly active in a cell, with most activities being similar between cell types. Individual TFs can have multiple gene regulatory activities, including chromatin opening and enhancing, promoting and determining transcription start site (TSS) activity, consistent with the view that the TF binding motif is the key atomic unit of gene expression.Peer reviewe
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