Search

This article proposes a new discrete-time predictive sliding mode control (DPSMC) for a parallel micropositioning piezostage to improve the motion accuracy in the presence of cross-coupling hysteresis nonlinearities and input constraints. Unlike the traditional linear discrete-time sliding mode control (DSMC), the proposed DPSMC is chattering free and has a faster convergence rate thanks to the design of a nonlinear discrete-time fast integral terminal sliding mode surface. Moreover, by combining with the receding horizon optimization, the sliding mode state is predicted to follow the expected trajectory of a predefined continuous sliding mode reaching law, which also allows the proposed controller to explicitly deal with constraints. The stability of the closed-loop system is analyzed under the model disturbances and constraints, and proves that the proposed DPSMC can offer a smaller quasi-sliding mode bandwidth than the traditional DSMC. The effectiveness of the proposed controller is validated by a series of numerical simulations and experiments. Results demonstrate the advantages of proposed DPSMC over the traditional DSMC method. [ABSTRACT FROM AUTHOR]

Probabilistic site characterization is the cornerstone of data-centric geotechnics, which underpins the digitalization in geotechnical engineering. The essential aspect of probabilistic site characterization is to reasonably infer the probability density distributions of geotechnical parameters, based on field and laboratory data. In this paper, a clay property database, SZ-CLAY/11/5130, was established by collecting geotechnical investigation reports from 52 engineering projects in Shenzhen city. This SZ-CLAY/11/5130 database was first compared with the global clay database CLAY/10/7490 and the Shanghai clay database SH-CLAY/11/4051, in terms of their sample ranges, correlations, and scatter plots. Then, the multivariate probability distribution of eight clay parameters was established using the training records selected from SZ-CLAY/11/5130, to characterize the generic correlations between multiple clay parameters. Based on Bayesian theory, the posterior distributions of clay mechanical parameters from a construction site in Shenzhen city were updated using both the site-specific correlations and the generic correlations given by SZ-CLAY/11/5130. The constructed multivariate probability density distribution is necessary for this updating step. [ABSTRACT FROM AUTHOR]

Learning causal structure in a complex system is crucial for causal inference and decision-making. Yet it remains a challenging problem due to the presence of unknown and varying feature spaces in most real-world scenes. Existing methods, including constraint-based and score-based methods, mainly rely on strict constraints, e.g., faithfulness, and cannot handle varying feature spaces. We propose a new gradient-based method ( C 2 S L I F S ) for learning causal structures from dynamic observational data with incremental instances and feature spaces. The C 2 S L I F S is designed as a nonlinear model with hidden variables, and utilizes the strategies of continuously optimizing reconstruction loss using dynamic weighting coefficients and equality constraints to update causal relationships, ensure acyclicity and avoid faithfulness constraints. We demonstrate the competitive performance of the proposed method through empirical evaluations against existing state-of-the-art methods. Besides that, two real-world case studies on two Bayesian network datasets (BNs), i.e., a protein signal network (Sachs) and a medical diagnostic alarm message network (Alarm), are conducted to elaborate on the effectiveness of C 2 S L I F S in real-world scenes. Code implementing the proposed algorithm is open-source and publicly available at https://github.com/youdianlong/C2SLIFS. • Initially study CSL from incremental instances and feature spaces instead of fixed ones. • Propose a nonlinear CSL model with hidden variables to improve performance and avoid faithfulness constraints. • Leverage gradient-based continuous optimization to adapt changes of feature spaces. • Relax the constraint bound using ζ instead of zero to enforce acyclicity in dynamic scenes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The incorporation of SiF 6 2− anion-pillars enhances CO 2 adsorption. • CuSiF 6 -TPPY reduces the energy barrier for *CO-to-*CHO while inhibiting desorption of CO. • Layer-to-layer model for photoinduced charge transfer suppresses electron-hole recombination. • Remarkable CH 4 yield of 13.84 μmol g−1 h−1 with a high selectivity of 88.78 %. The highly selective photoreduction of CO 2 to CH 4 is hindered by the sluggish eight-electron transfer process and rapid recombination of charge carriers. Herein, an anion-pillared metal–organic framework photocatalyst, CuSiF 6 -TPPY, is judiciously constructed for the highly selective photoreduction of CO 2 to CH 4. The polar SiF 6 2− pillars significantly enhance the CO 2 adsorption capacity to 96.56 cm3 g−1. Furthermore, the incorporation of SiF 6 2− pillars separates the HOMO and LUMO energy levels in distinct MOF layers, leading to a lower energy barrier for *CHO generation and a higher energy barrier for CO desorption. As a result, CuSiF 6 -TPPY delivers a CH 4 generation rate of 13.84 μmol g−1 h−1 with a high selectivity of 88.78 %, 4-times higher than TPPY ligands. Moreover, in-situ IR spectra and computational simulations further confirm the photoreduction pathways. [ABSTRACT FROM AUTHOR]

Path planning technology is one of the core technologies of intelligent space robot. Combining image recognition technology and artificial intelligence learning algorithm for robot path planning in unknown space environment has become one of the hot research issues. The purpose of this paper is to propose a spatial robot path planning method based on improved fuzzy control, aiming at the shortcomings of path planning in the current industrial space robot motion control process, and based on fuzzy control algorithm. This paper proposes a fuzzy obstacle avoidance method with speed feedback based on the original advantages of the fuzzy algorithm, which improves the obstacle avoidance performance of space robot under continuous obstacles. At the same time, we integrated the improved fuzzy obstacle avoidance strategy into the behavior-based control technology, making the avoidance become an independent behavioral unit. Divide the path planning into a series of relatively independent behaviors such as fuzzy obstacle avoidance, cruise, trend target, and deadlock by the behavior-based method. According to the interaction information between the space robot and the environment, each behavior acquires the dominance of the robot through the competition mechanism, making the robot complete the specific behavior at a certain moment, and finally realize the path planning. Furthermore, to improve the overall fault tolerance of the space, robot we introduced an elegant downgrade strategy, so that the robot can successfully complete the established task in the case of control command deterioration or failure of important information, avoiding the overall performance deterioration effectively. Therefore, through the simulation experiment of the virtual environment platform, MobotSim concluded that the improved algorithm has high efficiency, high security, and the planned path is more in line with the actual situation, and the method proposed in this paper can make the space robot successfully reach the target position and optimize the spatial path, it also has good robustness and effectiveness. [ABSTRACT FROM AUTHOR]

• A medaka embryo development monitoring method using differential EIS is proposed. • The proposed method has merits of eliminating the effect of EDL. • The extracted electrical characteristics reflect physiological changes of embryo well. A medaka embryo development monitoring method using differential Electrical Impedance Spectroscopy (EIS) is proposed. Impedance difference between measurement system with and without embryo is innovatively introduced to analyze embryo's development. Electrical characteristics of embryo are extracted from differential EIS. The proposed method has merits of eliminating the effect of electrical double layer (EDL) between electrodes and suspension. Besides relaxation frequency and its corresponding real/imaginary values of embryo, relaxation models and their fitting parameters are also extracted as properties of embryo in different developmental stages. In simulation, models of medaka embryo in 13 developmental stages from zygote stage to hatching stage are built, the extracted electrical characteristics reflect morphological and physiological changes of embryo well. In experiment, the proposed method is used to monitor medaka embryo's development from neurula stage to hatching stage. It also show that the electrical characteristics reflect physiological properties of embryo sensitively. [ABSTRACT FROM AUTHOR]

A robust and practical force control system is crucial to the sensitive piezo-driven micromanipulation applications. This paper presents a new model-free robust finite-time force tracking controller for piezoelectric actuators (PEAs). The proposed controller composes of three intuitive terms: (1) a time-delay estimation (TDE) term that eliminates the requirement of detailed information about the PEA system, realizing model-free control; (2) a fast integral terminal sliding mode-based desired error dynamics injection term that ensures fast convergence and high tracking precision; (3) a correcting term based on adaptive fuzzy logic system that compensates for TDE errors caused by discontinuous nonlinearities and improves the robustness of the system. Force differential signal used in the controller is estimated online by a force state estimator. Stability of the closed-loop system and finite-time convergence are analyzed in theory. Comparative experiments are carried out on a PEA system with two superposed PEAs. Results show that the proposed control strategy has faster convergence, higher tracking accuracy and stronger robustness compared with the traditional TDE-based force controllers. [ABSTRACT FROM AUTHOR]

Improving the control performance of active vibration isolation systems is crucial to provide an ultra-quiet environment for precision instruments. This paper presents a new fractional-order robust model reference adaptive controller for the piezo-actuated active vibration isolation systems with a relative-degree-one model. One advantage of the proposed controller lies in that its controller parameters are adjusted online by fractional proportional–integral-type adaptive laws, which not only speeds up the convergence of the closed-loop system, but also improves the control energy efficiency. Moreover, the proposed controller only uses the measurable input and output of the plant as feedback signals, which is convenient for controller implementation. The stability of the closed-loop system is proved based on the Lyapunov theory in detail. The optimal values of the fractional order and adaptive gains for adaptive laws are determined using the multi-objective genetic algorithm through off-line simulation. Comparative experiments on the piezo-actuated active vibration isolation systems are conducted to verify the effectiveness of the proposed controller. Results show that the proposed controller achieves satisfactory isolation performance in a wider frequency band of 20–500 Hz, and simultaneously reduces the control effort compared with the traditional MRAC methods. [ABSTRACT FROM AUTHOR]

The robust control issues in trajectory tracking of an unmanned aerial robot (UAR) are challenging tasks due to strong parametric uncertainties, large nonlinearities, and high couplings in robot dynamics. This paper investigates the dynamical modelling and robust control of an aerial robot using a hexarotor with a 2-degrees-of-freedom (DOF) manipulator in a complex aerial environment. Firstly, the kinematic model and dynamic model of the aerial robot are developed by the Euler-Lagrange method. Afterwards, a linear active disturbance rejection control is designed for the robot to achieve a high-accuracy trajectory tracking goal under heavy lumped disturbances. In this control scheme, the modelling uncertainties and external disturbances are estimated by a linear extended state observer, and the high tracking precision is guaranteed by a proportion-differentiation (PD) feedback control law. Meanwhile, an artificial intelligence algorithm is applied to adjust the control parameters and ensure that the state variables of the robot converge to the references smoothly. Furthermore, it requires no detailed knowledge of the bounds on unknown dynamical parameters. Lastly, numerical simulations and experiments validate the efficiency and advantages of the proposed method. [ABSTRACT FROM AUTHOR]

A priori attitude information can improve the success rate and reliability of Global Navigation Satellite System (GNSS) multi-antennae attitude determination. However, a priori attitude information is nonlinear, and integrating a priori information into the objective function rigorously will increase the complexity of an ambiguity domain search, such as the Multivariate Constrained-Least-squares Ambiguity Decorrelation Adjustment (MC-LAMBDA) method. In this paper, a new method based on attitude domain search is presented to make use of the a priori attitude angle information with high efficiency. First, the a priori information of pitch and roll is integrated into the search process to derive the analytic search step for attitude angle, and the integer candidates are determined by traversal search in the three-dimensional attitude domain. Then, the objective function is parameterised with Euler angles, and a non-iterative approximate method is utilised to simplify the iterative computation in calculating objective function values. Experimental results reveal that compared to the MC-LAMBDA method, our new method has the same success rate and reliability, but higher efficiency in making use of a priori attitude information. [ABSTRACT FROM AUTHOR]

Abstract The vibration isolation system is crucial to high-precision space systems. This paper studies dynamics and control of a six-axis vibration isolator via a flexible Stewart platform. The parasitic stiffness induced by flexible joints is considered in dynamics modeling and compensated in control for the first time. The explicit dynamic equations are established based on the pseudo-rigid-body model and the principle of virtual power. After validation by ADAMS/Flex and the finite element method, the dynamic equations are used for designing a decoupled controller. The control force is synthesized based on the leg's force and position feedback. The impact of bending and torsional stiffness of flexible joints is compensated and the MIMO system is consequently decoupled in modal space, making parameter design and performance implementation more convenient and effective. The identical sub-controller for every SISO system makes the six-DOF isolator achieve the capability of vibration isolation simultaneously for the six modes. With a proportional plus integral compensator as the sub-controller, the vibration isolation bandwidth and active damping can be regulated separately. [ABSTRACT FROM AUTHOR]

A novel fog-degraded image restoration model is proposed. This model is comprised of two parts: the defogging and the enhancement. The defogging work uses the three-dimensional color model to correct the weight of the multiscale retinex algebraic model and determine the golden defogging surround scale by the golden section. The enhancement part firstly marks the region of interesting (ROI) by double template, four-dimensional projection and morphological method. Then, the illumination is equalized in the frequency domain of the image, and the color fidelity is improved by power transformation. Subsequently, ROI is enhanced by adaptive piecewise linear method. Eventually, the enhanced ROI and the non-ROI are combined together by linear weight to generate the final result. The sufficient synthetic and real experiments prove that the proposed method has the satisfactory effects on the image detail recovery, the color fidelity and the balanced image vision in different image depth, thus meeting the demands of image monitoring and recognition. [ABSTRACT FROM AUTHOR]

The avoidance of singularities is critical to design and control of parallel robots. This paper aims at efficient determination of the maximal singularity-free joint space and workspace of a class of six-DOF parallel robots with six kinematic chains of same type. We represent the singularity-free joint space by a 6-cube and determine it firstly. The singularity-free workspace is generated by continuous motion of all active joints in the singularity-free joint space. As a result, the boundary of the workspace can be obtained with simultaneous consideration of position and orientation of the mobile platform. The size relation between the maximal singularity-free joint space and workspace is discussed. To efficiently determine the singularity-free joint space and workspace, we propose dual quaternion-based Jacobian matrices and construct an efficient algorithm. The algorithm detects singularities in a given joint space and simultaneously calculates its corresponding workspace. The computational costs of the proposed algorithm and the traditional one are compared using a 6-U P S parallel robot, leading to 9 seconds and 458 seconds respectively. Finally, both the maximal singularity-free joint space and workspace of a 6- P US parallel robot are determined to further demonstrate the effectiveness of the new approach. [ABSTRACT FROM AUTHOR]

A hyperbranched porous polymer P based on adamantane and pyrene was synthesized through the Sonogashira coupling reaction. The three-dimensional rigid molecular skeleton of adamantane makes polymer P porous. Compound M, which acts as the block moiety between two adamantane groups in polymer P, was also synthesized for the control experiment. Compared with M, the characteristics of P changed remarkably with it exhibiting different emission behaviors and performances for the detection of DNT. In saturated DNT vapor, the quenching efficiency (ηEP) of film P (82%) was remarkably superior compared with that of film M (22%). In addition, a series of films with different thicknesses and different amounts of polymer P were prepared. Results showed that the quenching efficiencies did not change with an increase in the film thickness. [ABSTRACT FROM AUTHOR]

Parallel piezostages have been prevalently applied in the micro-/nano-positioning field, but, unluckily, suffer from the undesired effects, like creep, hysteresis, vibration, cross coupling, and input saturation. To eliminate these nonlinearities, a new discrete-time sliding mode predictive control (DSMPC) with decoupling and damping properties (DSMPC-DDP) is proposed for a parallel six-axis piezostage devoted to cell micromanipulation. Firstly, a state-space-based decoupler is applied to make the MIMO system decoupled into six SISO subsystems, and then a damping compensator via the notch filter principle is selected to suppress the high-frequency vibration dynamics of six subsystems. After that, a feedback DSMPC law is designed for each decoupled and damped subsystem. Unlike the traditional linear model predictive control (MPC), the feedback DSMPC is developed based on a nonlinear discrete-time terminal sliding mode prediction model, leading to stronger robustness and faster convergence speed. Through the utilization of the receding horizon optimization, the sliding mode states are optimized to explicitly deal with the input constraints. The stability of the closed-loop subsystems is analyzed based on the terminal constraint theory. Finally, the effectiveness and superiority of the proposed controller is validated by a series of experimental tests. Results show that the proposed DSMPC-DDP scheme can achieve higher tracking accuracy and control bandwidth than the existing proportional–integral (PI) and MPC methods in the context of abovementioned nonlinearities. • A new DSMPC-DDP is proposed for a parallel six-axis piezostage. • Attenuating the creep, hysteresis, cross coupling, vibration, and input saturation simultaneously. • Providing rigorous stability analysis for the closed-loop control system. • Comprehensive comparative experiments are conducted for validating the superiority. [ABSTRACT FROM AUTHOR]

For the fast and efficient closed-loop real-time feedback control of 6-UPS parallel robot (6-UPS), a novel high efficiency calculation of the workspace is proposed and investigated. As a typical Nearly General Platform (NGP), 6-UPS has good symmetries. The symmetries effectively reduce computational cost and improve computational efficiency in the kinematics, singularity, dynamics, and optimization. To scrupulously demonstrate the symmetries of workspace, a novel algorithm is proposed. The modified Euler angles (T&T angles) are employed to represent the orientation matrix of 6-UPS, the inverse kinematics is analyzed, and the workspace of 6-UPS is obtained using the discretization algorithm. Meanwhile, the symmetries of the total orientation workspace are also proved. Compared with the traditional methods, the total orientation workspace reduces 5/6 computation cost, which means that the corresponding computation efficiency is increased by 6 times. Through theoretical and numerical calculations, the symmetries of the total orientation workspace of 6-UPS are verified. The proof of the symmetries lays a solid foundation for improving the computational efficiency of kinematics, dynamics, and control of 6-UPS. [ABSTRACT FROM AUTHOR]

A general method is presented for the inverse kinematics resolution of redundant manipulators with joint limits. The success of avoiding joint angular position limits of the original clamping weighted least-norm method is ascribable to the strength of the repulsive potential field function. However, the repulsive potential field function may lead to excessive joint angular velocities that can exceed the corresponding limits. We propose an improved clamping weighted least-norm method that adds an elastic field function into the original method for the sake of sustaining the constraints of joint angular velocity limits. Moreover, for hierarchical task-level construction, the priority of avoiding joint angular velocity limits is lower than that of avoiding joint angular position limits. To adequately illustrate the effectiveness of the proposed method, case studies were performed in comparison with other methods in singular configurations of a redundant manipulator. [ABSTRACT FROM AUTHOR]

We report a novel electrostatic self-excited resonator that achieves frequency jump and mode transition under DC voltage powering and control. By gradually increasing the DC voltage by 10%, the frequency output can suddenly jump to 5 times of its original value with the oscillation mode transitioning from the first-order to the second-order. Further, by implementing an artificial insect wing on the resonator, we also present a dual-mode flapping-wing actuator with dramatic increases in lift force and power output after a frequency jump. The frequency jump and mode transition due to small voltage variations have great potential in the field of multi-mode propulsion devices for high-mobility micro-robots. [ABSTRACT FROM AUTHOR]

the six-axis vibration isolation system is essential for high-precision space systems. Its architecture is always designed based on the cubic-configuration Stewart platform, whose six flexible modes generally have different natural frequencies resulting in multiple resonances at various frequencies such that a uniform capability of vibration isolation cannot be achieved for the six flexible modes. To solve this problem, the dynamic isotropic design of the isolator is studied to make the six nonzero natural frequencies identical. The free-floating state of the isolator is taken into account and six design criteria of the dynamic isotropy are obtained. The internal relation between the dynamic isotropy and the kinematic isotropy is revealed and discussed. A decentralized active controller is then investigated for the isolator of dynamic isotropy. The controller decouples the six-axis vibration control into six identical control of a single-axis vibration isolator. The same control gains in each single-axis isolator reaches the optimum simultaneously for all the flexible modes such that a best performance of vibration isolation can be achieved. Finally, we present an example of an isolator of dynamic isotropy. With the proportional plus integral compensator, the uniform corner frequency and optimal active damping can eventually be achieved. [ABSTRACT FROM AUTHOR]

Nanofibers (NFs) have the advantages of tremendous flexibility, small size and a high surface-to-weight ratio and are widely used in sensors, drug carriers and filters. Patterned NFs have expanded their application fields in tissue engineering and electronics. Electrospinning (ES) is widely used to prepare nonwoven NFs by stretching polymer solution jets with electric forces. However, patterned NFs cannot be easily fabricated using ordinary ES methods: the process gradually deteriorates them as repulsion effects between the deposited NFs and the incoming ones increase while residual charges in the fibers accumulate. Repulsion effects are unavoidable because charges in the polymer solution jets are the fundamental forces that are meant to stretch the jets into NFs. TRIZ theory is an effective innovation method for resolving conflicts and eliminating contradictions. Based on the material–field model and the contradiction matrix of TRIZ theory, we propose a strategy to improve ES devices, neutralizing the charges retained in NFs by alternating the current power of the correct frequency, thus successfully fabricating patterned NFs with clear boundaries and good continuity. This study demonstrates a strategy for resolving conflicts in innovation processes based on TRIZ theory and fabricating patterned NFs for potential applications in flexible electronics and wearable sensors. [ABSTRACT FROM AUTHOR]

The forward kinematics is the basis of the design and control of the parallel robots. This paper aims to provide an efficient solution to the forward kinematics of a class of six-degrees-of-freedom parallel robots for real-time applications. With a unit dual quaternion used as the generalized coordinates of the robot system, the forward kinematic equations are derived to be a set of quadratic ones. An efficient algorithm is proposed to get the actual solution to them. The convergence and singularity problems of the new algorithm have been discussed. We have provided a convergence strategy and revealed the internal relation of the singularity with that of the parallel robot, proving the feasibility of the algorithm and giving the working condition in the practical applications. The new algorithm have been compared to the Newton's method for an 8-U P S parallel robot, resulting in the time consumptions of 0.2187 milliseconds and 14.25 milliseconds respectively. And then we perform a simulation of the state-feedback control for an 8- P US parallel robot. The two examples present the applications of the new algorithm and demonstrate its validity and efficiency. [ABSTRACT FROM AUTHOR]

The purpose of this paper is devoted to developing a chaotic artificial bee colony algorithm (CABC) for the system identification of a small-scale unmanned helicopter state-space model in hover condition. In order to avoid the premature of traditional artificial bee colony algorithm (ABC), which is stuck in local optimum and can not reach the global optimum, a novel chaotic operator with the characteristics of ergodicity and irregularity was introduced to enhance its performance. With input-output data collected from actual flight experiments, the identification results showed the superiority of CABC over the ABC and the genetic algorithm (GA). Simulations are presented to demonstrate the effectiveness of our proposed algorithm and the accuracy of the identified helicopter model. [ABSTRACT FROM AUTHOR]

Abstract: Nogo-A is a major form of growth inhibitory molecule (growth-IM) which inhibits axonal regeneration and neurite regrowth after neural injury. Bone marrow stromal cells (MSCs) have been shown to inhibit Nogo-A expression in vitro and in cerebral ischemic animal models. The present study was designed to investigate the effects of treatment with human MSCs (hMSCs) impregnated into collagen scaffolds on the expression of Nogo-A and axonal plasticity after traumatic brain injury (TBI). Adult male Wistar rats were injured with controlled cortical impact and treated either with saline, hMSCs-alone or hMSCs impregnated into collagen scaffolds (scaffold+hMSC) transplanted into the lesion cavity 7 days after TBI. Rats were sacrificed 14 days after TBI and brain tissues were harvested for immunohistochemical studies, Western blot analysis, laser capture microdissections and qRT-PCR to evaluate axonal density and Nogo-A protein and gene expressions. Our data showed that treatment of TBI with scaffold+hMSC significantly decreased TBI-induced Nogo-A protein expression and increased axonal density compared to saline and hMSC-alone treatments. In addition, scaffold+hMSC transplantation decreased Nogo-A transcription in oligodendrocytes after TBI. Scaffold+hMSC treatment was superior to hMSC-alone treatment in suppressing Nogo-A expression and enhancing axonal regeneration after TBI. Our data suggest that transplanting hMSCs with scaffolds down-regulates Nogo-A transcription and protein expression which may partially contribute to the enhanced axonal regeneration after TBI. [Copyright &y& Elsevier]

Parallel micropositioning piezostages are widely used in the micro-/nano-manipulation applications, but also subject to the nonlinear disturbances, like hysteresis, creep and cross-coupling effects. In this paper, a new fractional robust adaptive decoupled control (FRADC) is synthesized for a six-axis parallel micropositioning piezostage to improve the positioning accuracy. The proposed FRADC contains three intuitional terms: (1) a decoupling term that alleviates the coupled motions among different axes, making the controller implementation more convenient and efficient; (2) a feedforward compensation term based on a fractional normalized Bouc-Wen (FONBW) model, compensating for the rate-dependent hysteresis effect induced by the piezoelectric actuators; (3) a feedback model reference adaptive control (MRAC) term with fractional proportional-plus-integral-type updating rules that suppresses the creep effect, parameters uncertainty and external disturbances, further enhancing the robustness and positioning accuracy. The stability of the closed-loop system is analyzed in theory. The effectiveness of the proposed FRADC is experimentally validated by comparing with the standalone inverse-FONBW-based feedforward control, the standalone feedback fractional MRAC, and the traditional integer-order control methods. Results demonstrate that the proposed FRADC can guarantee higher positioning accuracy for the piezostage system in wider control bandwidth. [ABSTRACT FROM AUTHOR]

Abstract: The beneficial effects of simvastatin on experimental traumatic brain injury (TBI) have been demonstrated in previous studies. In this study, we investigated the effects of simvastatin on axonal injury and neurite outgrowth after experimental TBI and explored the underlying mechanisms. Wistar rats were subjected to controlled cortical impact or sham surgery. Saline or simvastatin was administered for 14 days. A modified neurological severity score (mNSS) test was performed to evaluate functional recovery. Immunohistochemistry studies using synaptophysin, neurofilament H (NF-H) and amyloid-β precursor protein (APP) were performed to examine synaptogenesis and axonal injury. Primary cortical neurons (PCNs) were subjected to oxygen glucose deprivation (OGD) followed by various treatments. Western blot analysis was utilized to assess the activation of phosphatidylinositol-3 kinase (PI-3K)/Akt/mammalian target of rapamycin (mTOR) and glycogen synthase kinase 3β (GSK-3β)/adenomatous polyposis coli (APC) pathways. Simvastatin decreased the density of APP-positive profiles and increased the density of NF-H -positive profiles. Simvastatin reduced mNSS, which was correlated with the increase of axonal density. Simvastatin treatment stimulated the neurite outgrowth of PCNs after OGD, which was attenuated by LY294002 and enhanced by lithium chloride (LiCl). Simvastatin activated Akt and mTOR, inactivated GSK-3β and dephosphorylated APC in the injured PCNs. Our data suggest that simvastatin reduces axonal injury, enhances neurite outgrowth and promotes neurological functional recovery after experimental TBI. The beneficial effects of simvastatin on neurite outgrowth may be mediated through manipulation of the PI-3K/Akt/mTOR and PI-3K/GSK-3β/APC pathways. [Copyright &y& Elsevier]

To reduce the rejection rate of products, a novel single-piece heavy-load force sensor with a full-scale load of 150 t and a working frequency of 10 Hz is designed, manufactured and evaluated for the dynamic impact force measurement of the punch. The confined space of the punch holder limits the size of the fabricated sensor at φ166 mm × 45 mm. The sensor is characterized by an integrated fixture with four bearing carriers and one strain beam, which can ensure both strong stiffness and high sensitivity for the sensor simultaneously. A universal hydraulic machine with full-scale 300 t is employed to accomplish static calibration. The results show that linear calibration slopes for the sensor is within 2%. Site test is then performed for further verifying sensor performance. [ABSTRACT FROM AUTHOR]

This study is mainly about the designation of a new type of haptic device and an asymmetric teleoperation robot system. Aiming at the problems of tracking and transparency of an asymmetric teleoperation system, a robust control algorithm based on a state observer was proposed. The Haptic Device was designed and was chosen as the master-robot of the system. The Baxter dual-arm robot was chosen as the slave-robot of the system. The simulation experiment of robust control based on a state observer of the asymmetric teleoperation robot was carried out. The experiment results showed that the maximum values of displacement tracking errors in three directions x, y, and z are 0.02 m, 0.01 m, and 0.015 m, respectively. Compared with single- joint PID control, the performance of the new control algorithm is improved. The force feedback experiment on the real asymmetric teleoperation robot system was carried out. The results showed that the force feedback wave is consistent with the actual situation and showed that the robust control algorithm proposed is superior to PID. Therefore, the algorithm perfectly satisfied the system. The experiment parameters also demonstrate that the haptic device satisfies the design requirements of the asymmetric teleoperation robots system and the industry standards. [ABSTRACT FROM AUTHOR]

The parallel robotic manipulator has attracted many researchers’ attention and it also has growing applications to different areas. This paper proposes a 3-UPU (universal–prismatic–universal) translational parallel robotic manipulator with an equal offset in its six universal joints, based on the zero offset 3-UPU parallel manipulator. The kinematics of the new manipulator is analyzed and its inverse and forward kinematics solutions are provided. The conclusion is that its forward kinematics has 16 solutions instead of two in the zero offset manipulator. [Copyright &y& Elsevier]

• A novel position measurement approach of a single particle using EIS is proposed. • A general expression is proposed to fit impedance distribution of different position. • SVR is innovatively introduced to tackle the inverse problem of position estimation. A novel position measurement approach for a single particle in a channel using Electrical Impedance Spectroscopy (EIS) only with two pairs of electrodes is proposed. The proposed approach is label-free, non-invasive and is very accurate in measurement domain by using machine learning method. Relationship between the single particle's position and the measured impedances is described by a set of nonlinear equations showing excellent fitting performance with R-square reaching 0.9999. Finding accurate analytical solution of the particle's position is the inverse problem, it is tackled by a well-trained Support Vector Regression (SVR) model with the help of multi-frequency EIS. The proposed approach is evaluated by simulation models with a single particle in 100 different positions. The results show that the approach performs an outstanding position measurement accuracy to reach 99.25%. Comparing with EIT, it has more simple structure, less measurement time and more accurate measurement results. [ABSTRACT FROM AUTHOR]

Two tiphenylamine-based materials SM-1 and SM-2 were synthesized via simple one-step synthetic progress, which exhibits aggregation induced emission (AIE) in DMSO/H 2 O (1/9, v/v) solution due to intermolecular interactions and the restriction of intramolecular rotation in the aggregated state. The relationships between their structures and photophysical properties were studied via spectroscopic methods and density functional theory (DFT) calculations. The single crystal data of SM-1 and SM-2 revealed that multiple intermolecular interactions between molecules. Due to the excellent AIE nature of the two compounds. SM-1 and SM-2 were highly sensitive toward PA in the aggregated state. The quenching constant (K SV) of SM-2 was 5.33 × 104 M−1, and SM-1 was 1.1 × 105 M−1, with limit of detection (LOD) were 1.9 μM and 93 ppb for SM-1 and SM-2, respectively. For this reason, it shows that AIE materials are promising candidate in detection of explosives. • SM-1 and SM-2 exhibits aggregation induced emission (AIE) properties in DMSO/H 2 O (1/9, v/v) solution. • Compounds SM-1 and SM-2 showed high sensitivity toward PA in aqueous medium. The quenching constant (K SV) of SM-2 was 5.3 × 104 M−1, and SM-1 was 1.1 × 105 M−. • The limit of detection (LOD) was 93 ppb for SM-1 and 1.9 μM for SM-2, respectively. [ABSTRACT FROM AUTHOR]

Image segmentation is a crucial topic in image analysis and understanding, and the foundation of target detection and recognition. Image segmentation, essentially, can be considered as classifying the image according to the consistency of the region and the inconsistency between regions, it is widely used in medical and criminal investigation, cultural relic identification, monitoring and so forth. There are two outstanding common problems in the existing segmentation algorithm, one is the lack of accuracy, and the other is that it is not widely applicable. The main contribution of this paper is to present a novel segmentation method based on the information entropy theory and multi-scale transform contour constraint. Firstly, the target contour is initially obtained by means of a multi-scale sample top-hat and bottom-hat transform and an improved watershed method. Subsequently, in terms of this initial contour, the interesting areas can be finely segmented out with an innovative 3D flow entropy method. Finally, the sufficient synthetic and real experiments proved that the proposed algorithm can greatly improve the segmentation effect. In addition, it is widely applicable. [ABSTRACT FROM AUTHOR]

The spatial-based method has become the most widely used method in improving the visibility of images. The visibility improving is mainly to remove the noise in the image, in order to trade off denoising and detail maintaining. A novel adaptive non-local means-based nonlinear fitting method is proposed in this paper. Firstly, according to the smoothness of the intensity around the central pixel, eight kinds of templates with different precision are exploited to approximate the central pixel through a novel adaptive non-local means filter design; the approximate weight coefficients of templates are derived from the approximation credibility. Subsequently, the fractal correction is used to smooth the denoising results. Eventually, the Rockafellar multiplier method is employed to generalize the smooth plane fitting to any geometric surface, thus yielding the optimal fitting of the center pixel approximation. Through a large number of experiments, it is clearly elucidated that compared with the classical spatial iteration-based methods and the recent denoising algorithms, the proposed algorithm is more robust and has better effect on denoising, while keeping more original details during denoising. [ABSTRACT FROM AUTHOR]

Robot-assisted training is a promising technology in clinical rehabilitation providing effective treatment to the patients with motor disability. In this paper, a multi-modal control strategy for a therapeutic upper limb exoskeleton is proposed to assist the disabled persons perform patient-passive training and patient-cooperative training. A comprehensive overview of the exoskeleton with seven actuated degrees of freedom is introduced. The dynamic modeling and parameters identification strategies of the human-robot interaction system are analyzed. Moreover, an adaptive sliding mode controller with disturbance observer (ASMCDO) is developed to ensure the position control accuracy in patient-passive training. A cascade-proportional-integral-derivative (CPID)-based impedance controller with graphical game-like interface is designed to improve interaction compliance and motivate the active participation of patients in patient-cooperative training. Three typical experiments are conducted to verify the feasibility of the proposed control strategy, including the trajectory tracking experiments, the trajectory tracking experiments with impedance adjustment, and the intention-based training experiments. The experimental results suggest that the tracking error of ASMCDO controller is smaller than that of terminal sliding mode controller. By optimally changing the impedance parameters of CPID-based impedance controller, the training intensity can be adjusted to meet the requirement of different patients. [ABSTRACT FROM AUTHOR]

Background: Classical swine fever and porcine reproductive and respiratory syndrome have seriously affected the development of the swine breeding industry in China. Vaccine immunization remains the main way to prevent these infections. The aim of this study was to establish an optimized protocol for vaccine immunization against classical swine fever virus (CSFV) and porcine reproductive and respiratory syndrome virus (PRRSV). Methods: Blood samples were collected from the anterior vena cava of pigs after immunization, and blood indices, secreted levels of specific antibodies and neutralizing antibodies associated with humoral immunity, the proliferation capacity of T lymphocytes as a measure of cellular immunity, and secreted levels of IFN-γ and TNF-α were determined. Results: The results showed that simultaneous immunization against CSFV and PRRSV infections induced strong and specific humoral and T-cellular immune responses, high levels of cytokine IFN-γ secretion and delayed secretion of cytokine TNF-α. Moreover, significantly higher lymphocyte percentages and red blood cell and leukocyte counts were found in the group simultaneously immunized against CSFV and PRRSV. However, no statistically significant differences were observed in hemoglobin values, neutrophil counts, and median cell percentages among the S + PRRS, PRRS-S, and S-PRRS groups. Conclusion: This study demonstrated that simultaneous immunization against CSFV and PRRSV had the advantages of inducing a rapid, enhanced, and long-lasting immune response. These findings provide a theoretical basis for the establishment of a reasonable and optimized vaccine immunization protocol against CSFV and PRRSV in combination with a variety of other vaccine inoculations. [ABSTRACT FROM AUTHOR]

A novel microfeed mechanism for cell injection driven by a piezoelectric actuator (PEA) was developed in this study to fulfill the requirement of a precise cell membrane puncture. A bridge-type displacement amplification mechanism was designed based on a compliant mechanism principle and the micrometric displacement characteristic of the PEA to realize the zero-clearance precision motion of the microfeed mechanism using a flexure hinge as a supporting member. Static and modal analyses and structural optimization specific to the bridge-type amplification mechanism were performed to acquire a high inherent frequency and a large displacement amplification coefficient. A simulation verification of the mechanism's mechanical performance was implemented. A sliding-mode control strategy was proposed, considering that the complicated nonlinear hysteresis effect of PEA might cause low system precision. Cell puncturing experiments were performed on zebrafish embryos to demonstrate the performance of the proposed methodology. In comparison with existing studies, the manipulation precision of the proposed technique was less than 1.1 μm with a strong robustness. Thus, this new approach could be beneficial for the progress of cell puncture technology. [ABSTRACT FROM AUTHOR]

Manganese monoxide (MnO) is a promising anode material for lithium ion batteries, but it often shows poor electrochemical performance due to some inevitable drawbacks including intrinsic low electrical conductivity, poor stability, and severe polarization. In this work, a 1D core‐shell MnO@S, N co‐doped carbon material (MnO@SNC) was obtained by pyrolysis of MnO2@PPy precursor at 600 °C in N2 atmosphere. When evaluated as an anode for lithium ion batteries, the unique structure and composition advantages endow the as‐formed material with excellent lithium storage performance in terms of high specific capacity (955.5 mAh g−1 at a current density of 500 mA g−1), long‐term cycling stability (up to 500 cycles), and superior rate capability (458.7 mAh g−1 at a current density of 2 A g−1). The outstanding electrochemical performance could be attributed to the unique 1D core‐shell structure, abundant graphited carbon and MnO nanorods. [ABSTRACT FROM AUTHOR]

Piezoelectric micropositioning systems (PMSs) have been widely utilized in the high-precision manipulation applications, but are also subjected to undesired nonlinearities, like hysteresis, and parameter uncertainties. To solve this problem, this paper proposes a new robust sliding mode control scheme for a class of nonlinear PMSs with time-varying uncertainties. Different from the conventional sliding mode control (SMC), the proposed controller further combines the Fourier series-based function estimation technique, fuzzy logic system and adaptive learning algorithm to realize online estimation and compensation of system time-varying uncertainties without their boundary information. The adaptive laws of Fourier coefficients and fuzzy adjustable parameters are obtained via the Lyapunov stability theory. Compared with the existing SMC methods, the proposed control effectively eliminates the control chattering problem, and guarantees the convergence of the tracking error in finite time in the presence of time-varying uncertainties. Theoretical analysis and numerical simulation results show that the proposed control strategy can meet the high-speed, high-precision robust tracking performance requirements of PMSs for micro/nano-manipulation applications. [ABSTRACT FROM AUTHOR]

We demonstrate a Nd : YLF-YVO4 intracavity Raman laser in the 1.5 μm eye-safe region. The fundamental wave at 1314 nm from the end-pumped Nd :YLF is down-converted to 1488 nm, utilizing the 890 cm−1 Raman shift of an YVO4 laser crystal. We use two etalons in the fundamental cavity and Stokes cavity, respectively, to suppress their spectral line width. Under a diode pump power of 43 W at 806 nm, we obtain an average Stokes output power of 3.75 W at an acousto-optic Q-switched pulse repetition frequency of 20 kHz, corresponding to an optical efficiency of 8.7%. With the etalons used, the spectral line width of the Stokes laser is narrowed from over 0.2 to 0.04 nm. The beam quality factor of the eye-safe Stokes output is measured to be 1.12 and 1.19 in the x and y directions, respectively. [ABSTRACT FROM AUTHOR]

Abstract A new carbazole-based naked-eye colorimetric and fluorescent sensor CPPB with aggregation induced emission (AIE) effect was successfully synthesized. The solid powder of CPPB emitted intense yellow fluorescence, and its emission wavelength and fluorescence intensity in DMSO/H 2 O solution varied with the percentage of water (f w). Nano-aggregates of CPPB molecules were prepared by increasing f w of DMSO/H 2 O solution, and the optimal aggregation state of CPPB was reached in 99% aqueous DMSO solution with the maximum fluorescence intensity. Moreover, CPPB displayed high selectivity and sensitivity toward cyanide anions (CN−) in 99% aqueous DMSO solution even in the presence of other competitive anions (CN−, F−, Cl−, AcO−, NO 3 −, I−, CO 3 2−, HCO 3 −, HSO 3 −, SO 4 2−, S2−, HS−, OH−, H 2 PO 4 − and HPO 4 2−) and the reactive oxygen species (H 2 O 2 , O 2 ·−, 1O 2 , t-BuOOH and ·OH). The sensing mechanism for CN− was confirmed by optical spectral studies, 1H NMR titration, HRMS spectra, Job's plot analyses and DFT calculations. Sensor CPPB for CN− detection revealed extremely low detection limit (67.4 nM), high anti–interference ability, wide pH response range (3.0–10.0) as well as the immediate response (15 s). Furthermore, the CPPB -based test strips were applied to detect CN− qualitatively and quantitatively in 100% aqueous solution. Graphical abstract We have successfully developed sensor CPPB, which exhibited distinct aggregation induced emission (AIE) effect, and detected CN− based on naked-eye colorimetric and fluorescent sensing with high selectivity and great sensitivity. Image 1 Highlights • Carbazole-based sensor CPPB was designed and synthesized, which exhibited obvious aggregation induced emission (AIE) effect. • Sensor CPPB detected CN− in 99% aqueous DMSO solution, and the test strips of CPPB recognized CN− in 100% aqueous solution. • The detection limit of CPPB for CN− were at nanomolar level in 99% aqueous DMSO solution. • Colorimetric responses of CPPB toward CN− were visible with the naked eyes under sunlight and UV lamp (365 nm). [ABSTRACT FROM AUTHOR]

In this paper, a new composite controller (feedforward + feedback) is proposed for the trajectory tracking control of a piezo-driven bridge displacement amplifier. A hysteresis model considering dynamic effects is established based on the modified Bouc–Wen (MBW) model, which can describe the asymmetry and frequency-dependence behaviors. The effectiveness of the modified model is verified by the experimental comparison. A feedforward controller is designed to compensate for hysteresis nonlinearity based on the inverse multiplicative structure of the modified model. A feedback controller with the Kalman observer is designed based on a modified model predictive control (MMPC). The proportional term and integral term of feedback error are introduced into the MPC control law to improve the response speed and reduce the steady-state error. The proposed MBW + MMPC is compared with MBW + proportional–integral–derivative (PID), and MBW + MPC. The experimental tracking results of continuously differentiable signals and non-differentiable signals verify MBW + MMPC feasibility and show that it can improve tracking performance. [ABSTRACT FROM AUTHOR]

In order to meet the requirement of continuous pouring in many varieties and small batches in casting production, a mobile heavy load pouring robot is developed based on a new 4-UPU parallel mechanism due to its strong carrying capacity. Firstly, the instantaneous motion characteristics of the novel 4-UPU parallel mechanism with four degrees of freedom (DOF) are analyzed using screw theory. By using the geometric method, both the forward and inverse kinematic solutions of the proposed robot system are given out. Secondly, based on a common pouring ladle, the volume change of pouring liquid in pouring process and the relationship between tilting angular velocity and flow rate are analyzed, and the results show that the shape of the ladle and the design of the pouring mouth have great influence on the tilting model. It is an important basis for the division of the sectional model. Finally, a numerical example is given to verify the effectiveness of the developed tilting model. The mapping relation between the tilting model and the parallel mechanism shows that the pouring flow can be adjusted by controlling the movement of parallel manipulator. The research of this paper provides an important theoretical basis for the position control of mobile heavy load pouring robot and the research of pouring speed control. [ABSTRACT FROM AUTHOR]

The prognostic significance of hypoxia inducible factor‑1α (HIF‑1α) expression in tumors and the levels of preoperative hemoglobin in clear cell renal cell carcinoma (ccRCC), with or without concomitant chronic obstructive pulmonary disease (COPD), was investigated. A total of 128 patients with ccRCC who underwent surgery were analyzed using retrospective methods. Overall survival (OS) and progression free survival (PFS) were analyzed with clinicopathological variables, including preoperative hemoglobin levels, COPD and the levels of HIF‑1α e xpression, b y K aplan‑Meier survival analysis. Levels of HIF‑1α expression were detected by immunohistochemistry and the multivariate analysis was performed by proportional hazards regression. High levels of HIF‑1α expression were associated with a higher pathological stage and histological grade in patients with ccRCC (P<0.05). The median OS and PFS of patients with concomitant COPD were shorter compared with patients without COPD (P<0.05). The levels of serum hemoglobin, HIF‑1α expression and COPD diagnosis were all identified as independent prognostic variables for the OS and PFS of patients with ccRCC. [ABSTRACT FROM AUTHOR]

A six-axis vibration isolation system is essential to high-precision space systems for attenuating vibrations on precise instruments. The kinematic optimal design is researched for the space six-axis vibration isolator via Stewart mechanism. Jacobian matrix is the basis of the kinematic performance index. However, the conventional Jacobian matrix is not usually dimensionally homogeneous due to the inhomogeneous physical units, caused by the different mathematical representations of the rotation and translation. In this paper, we propose a dual quaternion approach to derive the dimensionally homogeneous Jacobian matrix of a general six-axis parallel mechanism. Two quaternions are used to parameterize the rotation and translation of the platform. The dimensionally scaling factor for the generalized Jacobian matrix is defined as the ratio of the norms of the two quaternions. The dimensionally homogenous Jacobian matrix is then obtained and applied to the optimal design of the six-axis vibration isolator. The performance index of isotropy is considered to make the isolator minimum kinematic coupling in its working configuration. [ABSTRACT FROM AUTHOR]

Background: Classical swine fever and porcine reproductive and respiratory syndrome have seriously affected the development of the swine breeding industry in China. Vaccine immunization remains the main way to prevent these infections. The aim of this study was to establish an optimized protocol for vaccine immunization against classical swine fever virus (CSFV) and porcine reproductive and respiratory syndrome virus (PRRSV). Methods: Blood samples were collected from the anterior vena cava of pigs after immunization, and blood indices, secreted levels of specific antibodies and neutralizing antibodies associated with humoral immunity, the proliferation capacity of T lymphocytes as a measure of cellular immunity, and secreted levels of IFN-γ and TNF-α were determined. Results: The results showed that simultaneous immunization against CSFV and PRRSV infections induced strong and specific humoral and T-cellular immune responses, high levels of cytokine IFN-γ secretion and delayed secretion of cytokine TNF-α. Moreover, significantly higher lymphocyte percentages and red blood cell and leukocyte counts were found in the group simultaneously immunized against CSFV and PRRSV. However, no statistically significant differences were observed in hemoglobin values, neutrophil counts, and median cell percentages among the S + PRRS, PRRS-S, and S-PRRS groups. Conclusion: This study demonstrated that simultaneous immunization against CSFV and PRRSV had the advantages of inducing a rapid, enhanced, and long-lasting immune response. These findings provide a theoretical basis for the establishment of a reasonable and optimized vaccine immunization protocol against CSFV and PRRSV in combination with a variety of other vaccine inoculations. [ABSTRACT FROM AUTHOR]

Background: Classical swine fever and porcine reproductive and respiratory syndrome have seriously affected the development of the swine breeding industry in China. Vaccine immunization remains the main way to prevent these infections. The aim of this study was to establish an optimized protocol for vaccine immunization against classical swine fever virus (CSFV) and porcine reproductive and respiratory syndrome virus (PRRSV). Methods: Blood samples were collected from the anterior vena cava of pigs after immunization, and blood indices, secreted levels of specific antibodies and neutralizing antibodies associated with humoral immunity, the proliferation capacity of T lymphocytes as a measure of cellular immunity, and secreted levels of IFN-γ and TNF-α were determined. Results: The results showed that simultaneous immunization against CSFV and PRRSV infections induced strong and specific humoral and T-cellular immune responses, high levels of cytokine IFN-γ secretion and delayed secretion of cytokine TNF-α. Moreover, significantly higher lymphocyte percentages and red blood cell and leukocyte counts were found in the group simultaneously immunized against CSFV and PRRSV. However, no statistically significant differences were observed in hemoglobin values, neutrophil counts, and median cell percentages among the S + PRRS, PRRS-S, and S-PRRS groups. Conclusion: This study demonstrated that simultaneous immunization against CSFV and PRRSV had the advantages of inducing a rapid, enhanced, and long-lasting immune response. These findings provide a theoretical basis for the establishment of a reasonable and optimized vaccine immunization protocol against CSFV and PRRSV in combination with a variety of other vaccine inoculations. [ABSTRACT FROM AUTHOR]

Background We conducted this prospective nested case–control study for the hepatic artery and portal vein hemodynamic changes after orthotopic liver transplantation. Methods A total 128 cases of orthotropic liver transplantation were analyzed, including 25 cases of ischemic type biliary lesions (ITBL). The portal vein and hepatic artery flow velocities were detected by ultrasound on days 28, 42, and 84 after liver transplantation. In the GLM analysis of Lg(S/D), the P values of Group Effect, Time Effect, and Time × Group were 0.014, 0.376, and 0.008, respectively. Conclusion Our results show a relatively reduced hepatic artery S/D in ITBL, especially in extrahepatic ITBL. [ABSTRACT FROM AUTHOR]

Aims: Nitrogenous fertilizer has been recognized as a key factor regulating nitrous oxide (N2O) emissions from agricultural soils. However, the effect of nitrogen (N) fertilization of preceding season on soil N2O emission in subsequent season remain poorly understood. Methods: Herein, a field-based study was done to examine the effect of prior N fertilization on N2O emissions under a rapeseed-rice rotation (RR) system in central China. Treatments were as follows: no N fertilizer was applied in both rapeseed and rice-growing seasons (N0-0), N fertilizer (150 kg N ha−1 y−1) was only applied during rapeseed-growing season (N150-0,), N fertilizer (150 kg N ha−1 y−1) was applied in both rapeseed and rice-growing seasons (N150-150), and N fertilizer (150 kg N ha−1 y−1) was only applied during rice-growing season (N0-150). Soil N2O fluxes and the key soil factors (soil available C and N and their ratios, soil temperature and moisture) that further drive N2O emissions were determined after N fertilization in preceding and subsequent seasons. Results: The application of N fertilizer during the rapeseed-growing season caused a significant increase in soil N2O emission from rice-growing season, but no such promotion effect was observed during rapeseed growing season due to N fertilization during prior rice season. Higher N2O emission from rapeseed-growing season, after N fertilization was attributed to high soil mineral nitrogen content (including NH4+-N and NO3−-N). N2O efflux was higher when dissolved organic carbon (DOC) to NO3− content ratio (DOC/NO3−) was < 0.5 but lower when DOC/NO3− ratio was > 0.5 for both N150-0 and N150-150 treatments. Pulse N2O emission during the rice-growing period was observed due to higher soil DOC content derived from soil organic matter decomposition. The positive correlation between soil N2O fluxes and DOC/NO3− ratio for both N150-150 and N0-150, also revealed that soil available carbon to nitrogen ratio could be a crucial factor regulating peaks of N2O during the rice season. Structural equation model (SEM) displayed the explanation of impact factors on N2O emission was 62% during the rapeseed-growing season, while that explanation was 45% during the rice-growing season. Conclusions: These results showed that not only labile C and N content, but also soil DOC/NO3−, influenced by prior N fertilization, play a key role in soil N2O emissions under the RR system. [ABSTRACT FROM AUTHOR]

A nondestructive testing technique based on magnetic flux leakage is presented to inspect automatically the stay cables with large diameters of a cable-stayed bridge. Using the proposed inspection method, an online nondestructive testing (NDT) modular sensor is developed. The wreath-like sensor is composed of several sensor units that embrace the cable at equal angles. Each sensor unit consists of two permanent magnets and a hall sensor to detect the magnetic flux density. The modular sensor can be installed conveniently on cables with various diameters by increasing the number of sensor units and adjusting the relative distances between adjacent sensor units. Results of the experiments performed on a man-made cable with faults prove that the proposed sensor can inspect the status signals of the inner wires of the cables. To filter the interfering signals, three processing algorithms are discussed, including the moving average method, improved detrending algorithm, and signal processing based on a digital filter. Results show that the developed NDT sensor carried by a cable inspection robot can move along the cable and monitor the state of the stay cables. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is an autoimmune disease associated with advanced joint dysfunction. Madhuca indica J. F. Gmel, from the family Sapotaceae, is an Indian medicinal plant reported to have an array of pharmacological properties. The aim of present investigation was to determine the anti-arthritic potential of an isolated phytoconstituent from methanolic leaf extract of Madhuca indica (MI-ALC) against FCA-induced experimental arthritis. Polyarthritis was induced in female rats (strain: Wistar) via an intradermal injection of FCA (0.1 mL) into the tail. Polyarthritis developed after 32 days of FCA administration. Then rats were treated orally with an isolated phytoconstituent from MI-ALC at doses of 5, 10, and 20 mg/kg. Findings suggested that High-Performance Thin-Layer Chromatography, Fourier-Transform Infrared Spectroscopy, and Liquid Chromatography-Mass Spectrometry spectral analyses of the phytoconstituent isolated from MI-ALC confirmed the structure as 3,5,7,3′,4′-Pentahydroxy flavone (i.e., QTN). Treatment with QTN (10 and 20 mg/kg) showed significant (p < 0.05) inhibition of increased joint diameter, paw volume, paw withdrawal threshold, and latency. The elevated synovial oxidative stress (Superoxide dismutase, reduced glutathione, and malondialdehyde) and protein levels of Tumor necrosis factor-α (TNF-α) and Interleukin (ILs) were markedly (p < 0.05) reduced by QTN. It also effectively (p < 0.05) ameliorated cyclooxygenase-2 (COX-2), Nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-kβ) and its inhibitor-α (Ikβα), and ATP-activated P2 purinergic receptors (P2X7) protein expressions as determined by western blot analysis. In conclusion, QTN ameliorates FCA-induced hyperalgesia through modulation of elevated inflammatory release (NF-kβ, Ikβα, P2X7, and COX-2), oxido-nitrosative stress, and pro-inflammatory cytokines (ILs and TNF-α) in experimental rats. [ABSTRACT FROM AUTHOR]