207 research outputs found

    Elucidation of mechanism of Si-jun-zi decoction-induced reversal of spleen deficiency syndrome in rats by LC-QTOF/ MS metabolomics

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    Purpose: To explore the therapeutic effect and mechanism of action of Siā€“junā€“zi decoction (SJZD) in rat spleen deficiency syndrome.Methods: Spleen deficiency syndrome was induced in a rat model with reserpine. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) and partial least squaresdiscriminate models (PLS-DA) were used to analyze the difference in global metabolite profile within all groups. Variable importance projection (VIP > 1) and Studentā€™s tā€“test (p < 0.05) were used for biomarker selection.Results: Enzymatic results showed that the level of amylase (AMY), pepsin (LPS) and pepsase were significantly lower in the untreated rats than in normal control rats and SJZD group rats (P < 0.05). Histopathological analysis showed there were significant pathological changes in the untreated rats compared with the normal control group and SJZD group rats. PLS-DA score plots of the untreated group rats clustered separately from control rats, whereas SJZD group rats clustered closely to normal control rats. Twenty potential biomarkers, including phospholipid and fatty acids, were screened. The relative content of 20 metabolites showed significant differences in the untreated group compared with control and SJZD groups (p < 0.05). Six potentially perturbed metabolic pathways were found, which might be potential targets pathways for SJZD intervention in spleen deficiency syndrome.Conclusion: Metabolomics approach is an effective tool for understanding theĀ  therapeutic mechanisms of SJZD.Keywords: Siā€“junā€“zi decoction, Spleen deficiency syndrome, Metabolomics,Ā  LC-Q-TOF/M

    Message Passing Based Block Sparse Signal Recovery for DOA Estimation Using Large Arrays

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    This work deals with directional of arrival (DOA) estimation with a large antenna array. We first develop a novel signal model with a sparse system transfer matrix using an inverse discrete Fourier transform (DFT) operation, which leads to the formulation of a structured block sparse signal recovery problem with a sparse sensing matrix. This enables the development of a low complexity message passing based Bayesian algorithm with a factor graph representation. Simulation results demonstrate the superior performance of the proposed method

    Theoretical Solution for Tunnelingā€Induced Stress Field of Subdeep Buried Tunnel

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    In the traditional Kirsch solution of stress field induced by tunneling in rock mass, the body force was not taken into consideration, and therefore the Kirsch solution is limited to demonstrate stress redistribution of deepā€buried tunnel. In order to consider the effect of body force on the stress redistribution induced by tunneling, a new secondary stress field solution for tunnel between shallow and deep tunnel (called subdeep tunnel) is developed with elastic mechanics and complex function employed. The stress field from theoretical solution is verified by numerical models, and the results showed good agreements with each other. This solution can be the basic theory in the analysis of the stress and field of subdeep tunnel, which have not been valuated through theoretical study yet

    Stochastic evolutionary game analysis of food cooperation among countries along the Belt and Road from the perspective of food security

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    IntroductionIn recent years, the combination of the public health crisis and the climate crisis has greatly weakened the resilience of food systems. The Belt and Road food cooperation will make outstanding contributions to consolidate food security and reduce global poverty in countries along the Belt and Road.MethodsThis paper constructs a three-party stochastic evolutionary game model from the perspective of food security, distinguishes the difference between large and small countries by calculating the cereal self-sufficiency rate, which studies the cooperation strategy with the Belt and Road cereal large countries, cereal small countries and regulatory committees as the object. In addition, we introduce the Gaussian white noise characteristics to characterize the stochastic disturbance of the game system. Then we combine the mathematical derivation of the stochastic evolutionary game analysis with the simulation method, examine the effect of the stochastic disturbance factors on the cooperation, and find out the factors that affect the cooperation. And finally verifies the model and proves the reasonableness and practicability of the model.ResultsThe stochastic evolutionary game model analyzes the interaction of stochastic disturbance and influencing factors from a dynamic perspective, and the stability of evolution is related to the strength of Gaussian white noise. The level of effort of large cereal countries and the incentives of regulatory committees can have a positive impact, but high income in small cereal countries can lead to instability in the strategic choices of other players.DiscussionTaking the countries along the Belt and Road as the research object, Gaussian white noise is introduced to describe the stochastic external environment, discriminate the stability of the game system through stochastic differential equations, and analyze the influencing factors of the dynamic behavioral strategies of the parties in combination with simulation methods. To improve the capacity of national food security governance and help improve the resilience of the world food system

    A new insight into ductile fracture of ultrafine-grained Al-Mg alloys

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    It is well known that when coarse-grained metals undergo severe plastic deformation to be transformed into nano-grained metals, their ductility is reduced. However, there are no ductile fracture criteria developed based on grain refinement. In this paper, we propose a new relationship between ductile fracture and grain refinement during deformation, considering factors besides void nucleation and growth. Ultrafine-grained Al-Mg alloy sheets were fabricated using different rolling techniques at room and cryogenic temperatures. It is proposed for the first time that features of the microstructure near the fracture surface can be used to explain the ductile fracture post necking directly. We found that as grains are refined to a nano size which approaches the theoretical minimum achievable value, the material becomes brittle at the shear band zone. This may explain the tendency for ductile fracture in metals under plastic deformation.The authors gratefully acknowledge the financial support from the Vice-Chancellorā€™s Fellowship Grant and URC small grant at the University of Wollongong

    Impact of Water Scarcity on the Fenhe River Basin and Mitigation Strategies

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    This study produced a drought map for the Fenhe River basin covering the period from 150 BC to 2012 using regional historical drought records. Based on meteorological and hydrological features, the characteristics and causes of water scarcity in the Fenhe River basin were examined, along with their impact on the national economy and ecological environment. The effects of water scarcity in the basin on the national economy were determined from agricultural, industrial, and domestic perspectives. The impact on aquatic ecosystems was ascertained through an evolution trend analysis of surface water systems, including rivers, wetlands, and slope ecosystems, and subterranean water systems, including groundwater and karst springs. As a result of these analyses, strategies are presented for coping with water scarcity in this basin, including engineering countermeasures, such as the construction of a water network in Shanxi, and the non-engineering approach of groundwater resource preservation. These comprehensive coping strategies are proposed with the aim of assisting the prevention and control of water scarcity in the arid and semi-arid areas of China

    Stability for a New Class of GNOVI with ( Ī³

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    By using ordered fixed point theory, we set up a new class of GNOVI structures (general nonlinear ordered variational inclusions) with (Ī³G,Ī»)-weak-GRD mappings, discuss an existence theorem of solution, consider a perturbed Ishikawa iterative algorithm and the convergence of iterative sequences generated by the algorithm, and show the stability of algorithm for GNOVI structures in positive Hilbert spaces. The results in the instrument are obtained

    Bio-inspired plasmonic leaf for enhanced light-matter interactions

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    The mathematical concept of fractals is widely applied to photonics as planar structures ranging from terahertz resonators, optical antennas, to photodetectors. Here, instead of a direct mathematical abstract, we design a plasmonic leaf with fractal geometry from the outline of a leaf from Wargrave Pink. The enhanced light-matter interactions are observed numerically from the improvement in both absorption and near-field intensification. To demonstrate the effect experimentally, a three-dimensional fractal structure is realised through direct laser writing, which significantly improves the photothermal conversion. By virtue of the self-similarity in geometry, the artificial leaf improves the absorption of a 10-nm-thick gold film with 14ā€‰Ć—ā€‰ temperature increment compared to flat Au film. Not limited to the proof-of-concept photothermal experiment demonstrated here, the fractal structure with improved light-matter interactions can be utilised in a variety of applications ranging from non-linear harmonic generation, plasmonic-enhanced fluorescence, to hot electron generation for photocatalysis

    DT-driven memory cutting control method using VR instruction of boom-type roadheader

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    Aiming at the problems of low intelligence of current tunneling equipment, difficulty in describing over-excavation, under-excavation and abnormal collision in tunneling process, and difficulty in adapting traditional automatic cutting and memory cutting technology to complex geological conditions, a digital twin-driven virtual teaching memory cutting control method for cantilever roadheader is proposed. By analyzing the research situation of digital twin technology in the field of intelligent coal mining, the overall scheme of memory cutting control system of cantilever roadheader driven by digital twin is designed, and the key technology of memory cutting of cantilever roadheader under complex working conditions is studied. Firstly, the characteristics of digital twin and virtual reality technology are fully utilized to study the virtual teaching strategy under complex working conditions. Based on the Unity3D platform, the virtual twin model of the working face and equipment with the same size of the corresponding entity, the kinematics model of the cutting unit and the virtual collision detection model are established. The virtual model movement is controlled through the intelligent interactive interface at the virtual end, and the teaching trajectory is designed and optimized according to the workerā€™s experience, so that it can be used as the target expected trajectory of trajectory tracking to make up for the excessive dependence on the workerā€™s experience caused by the traditional underground manual teaching due to the harsh working conditions. Secondly, in order to improve the quality of section forming, the control method of teaching trajectory tracking and reproduction in memory automatic cutting stage is studied. The dynamic model of cutting part is established by Lagrange method, and the tracking control accuracy of end effector to teaching trajectory is improved by combining iterative learning with sliding mode control. Finally, the simulation control platform of the memory cutting of the cantilever roadheader is built. Through the real-time data transmission and interaction between the virtual space and the physical space and between the modules, the three-dimensional visual simulation of the memory cutting virtual teaching and trajectory tracking control process is completed in the virtual space, and then the memory automatic cutting trajectory tracking control command is generated and sent to the end effector of the physical entity of the cantilever roadheader to drive it to carry out the section forming cutting according to the teaching trajectory. At the same time, the physical sensor collects the pose data of the cantilever roadheader fuselage and the cutting arm, and reversely drives the virtual model to move synchronously. The closed-loop control of robot virtual model and physical entity is realized. On this basis, the virtual and real synchronization of the system, the motion consistency between the virtual prototype and the physical prototype, and the trajectory tracking and reproduction control accuracy are verified. The experimental results show that the system data transmission delay is low, which can ensure the virtual and real consistency and synchronization, and the trajectory tracking control accuracy meets the actual use requirements. This method provides a new idea for memory cutting and intelligent control of tunneling equipment
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