Curcumin Promotes Diabetic Foot Ulcer Wound Healing by Inhibiting miR-152-3p and Activating the FBN1/TGF-ß Pathway.

The objective of this study was to investigate the mechanism of curcumin in diabetic foot ulcer (DFU) wound healing. A DFU rat model was established, and fibroblasts were cultured in a high-glucose (HG) environment to create a cell model. Various techniques, including Western blot, RT‒qPCR, flow cytometry, Transwell, cell scratch test and H&E staining, were employed to measure the levels of relevant genes and proteins, as well as to assess cell proliferation, apoptosis, migration, and pathological changes. The results showed that miR-152-3p was overexpressed in DFU patients, while FBN1 was underexpressed. Curcumin was found to inhibit fibroblast apoptosis, promote proliferation, migration, and angiogenesis in DFU rats, and accelerate wound healing in DFU rats. In addition, overexpression of miR-152-3p weakened the therapeutic effect of curcumin, while overexpression of FBN1 reversed the effects of the miR-152-3p mimic. Further investigations into the underlying mechanisms revealed that curcumin expedited wound healing in DFU rats by restoring the FBN1/TGF-ß pathway through the inhibition of miR-152-3p. In conclusion, curcumin can suppress the activity of miR-152-3p, which, in turn, leads to the rejuvenation of the FBN1/TGF-ß pathway and accelerates DFU wound healing.

Interaction force modeling and analysis of the human-machine kinematic chain based on the human-machine deviation.

A mechanical model for a human-machine interaction force based on the man-machine kinematic chain is established. This is combined with screw theory and a virtual rigid body model for the human-machine interaction force is proposed. This model interprets the basic principle model of the human-machine contact force. The deviation of the human-machine kinematic chain is calculated using the virtual model. In order to carry out the calibration simulation for the model, a 6-sps parallel mechanism is taken as an example to illustrate the construction principle of the human-machine interaction virtual rigid body model. This is calibrated by introducing finite element software. Finally, using the knee exoskeleton as an example, a numerical simulation is introduced. This illustrates the relationship between the driving force of the exoskeleton, the human-machine deviation as well as the virtual stiffness. The modeling method of this paper provides theoretical reference for controller design of human-machine interaction forces in the future.

Investigation on the basic principles of human-machine contact force, based on screw theory.

In this paper, to introduce a spatial rigid body mechanics analytical method and start the analysis, the human-machine contact force is equivalent to a spatially rigid body: the mechanism and skin surfaces are equivalent to two different rigid planes, and the motion between the mechanism and skin surfaces is equivalent to virtual branches motion. By considering the elastic deformation of each virtual branch axis, an equivalent human-machine contact force model is established, along with the deformation coordination equation of each virtual branch. The analytical solution of the tension/compression and the expression of the internal force of each virtual branch are obtained by solving the pseudo inverse and weighted generalized inverse solutions of the human-machine contact force. The physical meaning of the internal force of each virtual branch is also denoted. In addition, this paper contains an experimental platform for testing human-machine contact force, in which the linear stiffness of each branch is evaluated, therefore simulating and verifying the theoretical model introduced above. The contact force model proposed in this paper provides a theoretical basis for the development of human-machine synergetic motion.

Distributed Consensus Seeking With Different Convergence Performance Requirements: A Unified Control Framework.

In this article, we investigate distributed consensus seeking with multiple convergence performance requirements for single-integrator multiagent systems under undirected graphs. A unified distributed control framework is proposed to ensure consensus or practical consensus as well as performance time requirements, which contains most existing complex protocol schemes as special cases. In the proposed framework, three functions with specific properties in the controller play different roles and can be freely designed to achieve desired convergence performances, which guarantee a high-level scalability for multiple control requirements in addition to convergence time. For highlighting the compatibility and flexibility of the proposed method, four typical scenarios are discussed to reach exponential, finite-time, fixed-time, and appointed-time consensus seeking, respectively. Finally, numerical simulations are carried out to verify the effectiveness of the theoretical analysis.

Post-discharge experiences of patients with extracorporeal membrane oxygenation support: A qualitative study.

PURPOSE: To explore the life experiences of patients who have been discharged after undergoing extracorporeal membrane oxygenation (ECMO) support. DESIGN: A qualitative descriptive approach was used. METHODS: Patients who have undergone ECMO support and have been discharged were recruited. Thirteen participants were involved in this study. The data were collected through a semi-structured interview and analyzed using the Colaizzi method. FINDINGS: Four major themes in life experiences were reported by the participants: changes in physical function, changes in psychological state, active adaptation to daily life, and substantial rehabilitation needs. CONCLUSION: Different, continuous, and convenient post-discharge physical and mental interventions, social support, spiritual support, and rehabilitation services should be provided according to the patient's circumstances. We also call on the government to increase the patient reimbursement rate for ECMO treatment. These measures may help to improve the quality of life of patients.

Identifying Disconnected Agents in Multiagent Systems via External Estimators.

This article addresses the problem of identifying disconnected agents in multiagent systems via external estimators. Specifically, we employ external estimators with an appropriately designed decision rule to identify the disconnectedness (i.e., the status of being disconnected) between two arbitrarily chosen agents in formation-control multiagent systems. The design of the decision rule is inspired by the unit-root testing problem of autoregressive time series. To make the best possible decision, a best-effort procedure is also proposed. Then, by introducing the concept of connected components (or just components) in graph theory, and using the methods of consensus analysis and time-series analysis, we develop an analytical framework to show the theoretical performance of the designed decision rule. A particularly important result shown by our analysis is that the miss probability of the decision rule can converge to 0 as the number of data samples increases. Finally, simulation results validate the performance of the decision rule and the best-effort procedure, showing that they can perform well even in small samples.

Development and application of "Special defibrillator for teaching and training".

BACKGROUND: To provide an economical and practical defibrillator for first aid teaching and training, to reduce the cost of teaching and training, increase teaching and training equipment, provide trainees with more hands-on training sessions, and improve first aid capabilities. METHODS: Developing a special teaching defibrillator with the same structure and operation configuration as the clinical medical emergency defibrillator. The appearance, structure and operating accessories of the two defibrillators are the same. The difference between the defibrillator and the clinical medical emergency defibrillator are as follows: the clinical medical emergency defibrillator can be energized, and there are expensive electronic accessories and defibrillation accessories for charging and discharging in the machine. When discharging, the electrode plate has current discharged into the human body; the power plug of the "special defibrillator for teaching and training" is a fake plug. When the power is plugged in, no current enters the body and the machine. There are no expensive electronic accessories and defibrillation accessories for charging and discharging, and no current is discharged during discharge. Then compare the teaching effect of the special defibrillator for teaching and training and the clinical medical emergency defibrillator (including operation score and attitude after training). RESULTS: The scores of defibrillator operation in the experimental group of junior college students (87.77 ± 4.11 vs. 83.30 ± 4.56, P < 0.001) and the experimental group of undergraduate students (90.40 ± 3.67 vs. 89.12 ± 3.68, P = 0.011) were higher than those in the corresponding control group; The attitude of junior college students in the experimental group and undergraduate students in the experimental group after training was more positive than that of the corresponding control group (P < 0.05). CONCLUSIONS: The special defibrillator for teaching and training can save the purchase cost of teaching equipment, increase teaching and training resources, and improve the trainee's defibrillation ability, defibrillation confidence and defibrillation security.

Distributed Fixed-Time Coordination Control for Networked Multiple Euler-Lagrange Systems.

This work investigates the fixed-time distributed coordination control for multiple Euler-Lagrange systems and, in particular, addresses containment control with stationary/dynamic leaders as well as leaderless synchronization control. For the containment control scenario with stationary leaders, the subgraph associated with followers is directed. When dynamic leaders are involved, the information transfer between neighboring followers is bidirectional, for which a novel distributed estimator is developed. For the leaderless synchronization control scenario, the communication network among agents is unidirectional. Three fixed-time distributed control schemes are designed for the aforementioned three cases by applying the fixed-time stability theory. The convergence of the coordination control objectives can be achieved in a fixed time that does not depend on any initial conditions of agents' states, and the settling times are also explicitly derived. Finally, numerical simulations are presented to demonstrate the feasibility of the developed control strategies.

Distributed Model Predictive Control for Linear-Quadratic Performance and Consensus State Optimization of Multiagent Systems.

The optimal consensus problem of asynchronous sampling single-integrator and double-integrator multiagent systems is solved by distributed model predictive control (MPC) algorithms proposed in this article. In each predictive horizon, the finite-time linear-quadratic performance is minimized distributively by the control input with consensus state optimization. The MPC technique is then utilized to extend the optimal control sequence to the case of an infinite horizon. Conditions depending only on each agent's weighting scalar and sampling step are derived to guarantee the stability of the closed-loop system. Numerical examples of rendezvous control of multirobot systems illustrate the efficiency of the proposed algorithm.

Distributed Finite-Horizon Extended Kalman Filtering for Uncertain Nonlinear Systems.

In this paper, the state estimation problem is investigated for a class of discrete nonlinear systems via sensor networks. A novel robust distributed extended Kalman filter, which can handle norm-bounded uncertainties in both the system model and its Taylor series expansion, is developed with ensured estimation performance. The filter is distributed in the sense that for each sensor, only its own measurements and its neighbors' information are utilized to optimize the upper bound of the estimation error covariance. Besides, a sufficient condition for the proposed algorithm is derived, which is simple and user-friendly since it depends on the property of the original nonlinear system instead of the estimation error covariance calculated at every step. Finally, the simulation results are presented to demonstrate the effectiveness of the filtering algorithm.

Event-Based Multiagent Consensus Control: Zeno-Free Triggering via Lp Signals.

In this paper, we develop some new event-triggered algorithms for achieving distributed consensus for a multiagent system that guarantees fully Zeno-free triggerings for all the agents. In the proposed framework, each agent updates its control input only at its own triggering instants by using local measurements (i.e., relative states) with respect to neighboring agents, and such local measurements can be done in a local coordinate frame. For all agents, a positive Lp signal function is embedded in the event detector functions, which aims to avoid the possible comparison of an event error term to a zero threshold that may happen in a zero-crossing scenario. We further propose a Zeno-free self-triggered algorithm to achieve multiagent consensus, which enables discrete-time measurements and thus avoids continuous measurements between the neighboring agents. We also show that the proposed event-based consensus algorithms guarantee less frequent triggered events in a bounded time interval compared to the conventional algorithm without Lp signals. Simulations and comparisons are provided to validate the performance and effectiveness of the proposed event-based consensus schemes.

Some Necessary and Sufficient Conditions for Synchronization of Second-Order Interconnected Networks.

This paper presents some necessary and sufficient conditions for the synchronization of second-order interconnected networks, where fixed inner-linked connections with information communication exist. First, a novel derivation of the conditions for a second-order polynomial with complex coefficients to be Hurwitz is provided. Based on this, a sufficient and necessary condition is proposed for the synchronization of the coupled complex network. Next, the design method of the synchronization protocol is constructively given, where the upper and lower bounds of the control gains are obtained through the properties of the polynomial. In addition, we consider some special cases where the second-order model is a double integrator, or general multiagent model without fixed interactions. Finally, the simulation result is given to verify the theoretical analysis.

Distributed Formation Control of Multiple Quadrotor Aircraft Based on Nonsmooth Consensus Algorithms.

The problem of distributed formation control for multiple quadrotor aircraft in the form of leader-follower structure is considered in this paper. Based on a nonsmooth backstepping design, a novel consensus formation control algorithm is proposed and utilized. First, for the position control subsystem, based on the linear quadratic regulator optimal design method, a formation control law for multiple quadrotor aircraft is designed such that the positions of all the quadrotor aircraft converge to the desired formation pattern. The designed formation control law for position systems will generate the desired attitude for the attitude control systems. Second, for the attitude control subsystem described by unit quaternion, by employing the technique of finite-time control and switch control, a global bounded finite-time attitude tracking controller is designed such that the desired attitude can be tracked by the multiple quadrotor aircraft in finite time. Finally, numerical example is performed to demonstrate that all quadrotor aircraft converge to the desired formation pattern in the 3-D-space.

Cooperative Output Regulation of LTI Plant via Distributed Observers With Local Measurement.

Over the last decades, distributed output regulation problems have received much consideration due to its extensively applications in real world practices. Traditionally, it is assumed that each node obtains the same signal. However, an important observation is that each agent possesses different measurement due to the observability or configuration of the systems. To solve the output regulation problem in this case, we proposed a cooperative output regulation network, where each agent obtains a part of system output measurement on states of plant and exosystem. Distributed state observers and disturbance observers are designed in order to fuse the observed data. Different from traditional literatures, our design shows that even none of the agents can locally reconstruct the state of exosystem, it is still possible to design a networked system to track the reference signal properly. Conditions that guarantee the existence of parameters are given in the cases, where the network topologies are fixed and time-varying, respectively. The simulation results verify our method very effectively.

Impulsive synchronization of coupled dynamical networks with nonidentical Duffing oscillators and coupling delays.

This paper aims to investigate the synchronization problem of coupled dynamical networks with nonidentical Duffing-type oscillators without or with coupling delays. Different from cluster synchronization of nonidentical dynamical networks in the previous literature, this paper focuses on the problem of complete synchronization, which is more challenging than cluster synchronization. By applying an impulsive controller, some sufficient criteria are obtained for complete synchronization of the coupled dynamical networks of nonidentical oscillators. Furthermore, numerical simulations are given to verify the theoretical results.

Synchronization transitions on scale-free neuronal networks due to finite information transmission delays.

We investigate front propagation and synchronization transitions in dependence on the information transmission delay and coupling strength over scale-free neuronal networks with different average degrees and scaling exponents. As the underlying model of neuronal dynamics, we use the efficient Rulkov map with additive noise. We show that increasing the coupling strength enhances synchronization monotonously, whereas delay plays a more subtle role. In particular, we found that depending on the inherent oscillation frequency of individual neurons, regions of irregular and regular propagating excitatory fronts appear intermittently as the delay increases. These delay-induced synchronization transitions manifest as well-expressed minima in the measure for spatial synchrony, appearing at every multiple of the oscillation frequency. Larger coupling strengths or average degrees can broaden the region of regular propagating fronts by a given information transmission delay and further improve synchronization. These results are robust against variations in system size, intensity of additive noise, and the scaling exponent of the underlying scale-free topology. We argue that fine-tuned information transmission delays are vital for assuring optimally synchronized excitatory fronts on complex neuronal networks and, indeed, they should be seen as important as the coupling strength or the overall density of interneuronal connections. We finally discuss some biological implications of the presented results.

Delay-induced multiple stochastic resonances on scale-free neuronal networks.

We study the effects of periodic subthreshold pacemaker activity and time-delayed coupling on stochastic resonance over scale-free neuronal networks. As the two extreme options, we introduce the pacemaker, respectively, to the neuron with the highest degree and to one of the neurons with the lowest degree within the network, but we also consider the case when all neurons are exposed to the periodic forcing. In the absence of delay, we show that an intermediate intensity of noise is able to optimally assist the pacemaker in imposing its rhythm on the whole ensemble, irrespective to its placing, thus providing evidences for stochastic resonance on the scale-free neuronal networks. Interestingly thereby, if the forcing in form of a periodic pulse train is introduced to all neurons forming the network, the stochastic resonance decreases as compared to the case when only a single neuron is paced. Moreover, we show that finite delays in coupling can significantly affect the stochastic resonance on scale-free neuronal networks. In particular, appropriately tuned delays can induce multiple stochastic resonances independently of the placing of the pacemaker, but they can also altogether destroy stochastic resonance. Delay-induced multiple stochastic resonances manifest as well-expressed maxima of the correlation measure, appearing at every multiple of the pacemaker period. We argue that fine-tuned delays and locally active pacemakers are vital for assuring optimal conditions for stochastic resonance on complex neuronal networks.

Network synchronizability analysis: a graph-theoretic approach.

This paper addresses the fundamental problem of complex network synchronizability from a graph-theoretic approach. First, the existing results are briefly reviewed. Then, the relationships between the network synchronizability and network structural parameters (e.g., average distance, degree distribution, and node betweenness centrality) are discussed. The effects of the complementary graph of a given network and some graph operations on the network synchronizability are discussed. A basic theory based on subgraphs and complementary graphs for estimating the network synchronizability is established. Several examples are given to show that adding new edges to a network can either increase or decrease the network synchronizability. To that end, some new results on the estimations of the synchronizability of coalescences are reported. Moreover, a necessary and sufficient condition for a network and its complementary network to have the same synchronizability is derived. Finally, some examples on Chua circuit networks are presented for illustration.

Complex network synchronizability: analysis and control.

In this paper, the investigation is first motivated by showing two examples of simple regular symmetrical graphs, which have the same structural parameters, such as average distance, degree distribution, and node betweenness centrality, but have very different synchronizabilities. For a given network with identical node dynamics, it is further shown that two key factors influencing the network synchronizability are the network inner linking matrix and the eigenvalues of the network topological matrix. Several examples are then provided to show that adding new edges to a network can either increase or decrease the network synchronizability. In searching for conditions under which the network synchronizability may be increased by adding edges, it is found that for networks with disconnected complementary graphs, adding edges never decreases their synchronizability. Moreover, it is found that an unbounded synchronized region is always easier to analyze than a bounded synchronized region. Therefore to effectively enhance the network synchronizability, a design method is finally presented for the inner linking matrix of rank 1 such that the resultant network has an unbounded synchronized region, for the case where the synchronous state is an equilibrium point of the network.