This paper focuses on the observer-based leader-following formation tracking control for multirobot with obstacle avoidance. First, based on the leader-follower formation control method, setting the trajectory of the leader robot, then the follower robots track the leader robot. Second, an observer for the followers is designed to estimate the state of the leader robot, which can limit the estimation errors to a small value at short time-frame. Moreover, the gain controller and corrective controller are presented to complete the formation task and implement the trajectory transformation, respectively. In addition, an improved obstacle avoidance algorithm is devised to avoid the obstacles by adjusting the angle between the leader robot and the followers. Finally, the simulation results are presented to verify the effectiveness of the proposed control scheme. The main advantages of this paper are both an observer-based controller includes gain control and corrective control is developed for the nonlinear multi-robot system, and the obstacle avoidance problem during movement is solved with the optimal method. INDEX TERMS Multi-robot, formation control, observer-based, obstacle avoidance.

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Lead (Pb) is a ubiquitous and toxic heavy metal and it can damage the immune system in humans and animals. Many researchers have reported that Selenium (Se) could possess various pharmacological effects in mammals. However, few studies have been carried out to investigate the protective role of Se in birds, especially in chickens. In this study, we investigated the protective effects of Se against Pb-induced inflammatory responses and the expression of heat shock proteins (HSPs) in peripheral blood neutrophils. One hundred eighty Hy-Line brown chickens were randomly divided into the control group (Con group), Se supplementation group (+Se group), Pb supplementation group (+Pb group), and the Se and Pb compound group (Se+Pb group). On the 90th day of the experiment, the peripheral blood was collected to extract neutrophils, and then, the levels of HSPs and cytokines were examined. The results showed that, after Pb treatment, the levels of IL-(1β, 1R, 4, 8, 10, and 12β), TGF-β4, and HSP (27, 40, 60, 70, and 90) mRNA were significantly increased and levels of IL-2 and IFN-γ mRNA were decreased compared with those in the control group. Compared with the control group, the protein levels of HSP60 and HSP70 were also increased in the Pb treatment group. Co-administration of Se (1 mg/kg/day) and Pb resulted in a reversal of the Pb-induced cytokine changes in neutrophils accompanied by a significant decrease in HSPs. Our study demonstrated that Pb could decrease the immune function via changing the expression of cytokines and HSPs in chicken neutrophils, but Se could relieve the toxic effect induced by Pb.

Purpose Early diagnosis and treatment of atherosclerosis (AS) vulnerable plaque has important clinical significance for the prognosis of patients. In this work, the integrated diagnosis and treatment nanoparticles based on Gd-doped Prussian blue (GPB) were constructed for the fluorescence/MR dual-mode imaging and anti-ROS treatment of vulnerable AS plaques in vitro and in vivo. Methods To fabricate the theranostic NPs, GPB was modified with water-soluble polymer polyethyleneimine (PEI), fluorescence molecule rhodamine (Rd), and targeted molecule dextran sulfate (DS) step by step via electrostatic adsorption to construct GPRD NPs. The fluorescence/MR imaging ability and various nano-enzymes activity of GPRD NPs were detected, and the biocompatibility and safety of GPRD were also evaluated. Subsequently, RAW264.7 cells and ApoE -/- model mice were used to evaluate the effect of GPRD NPs on the targeted dual-mode imaging and anti-ROS treatment of vulnerable plaque in vitro and in vivo. Results The experimental results showed that our fabricated GPRD NPs not only displayed excellent MR/fluorescence dual-modality imaging of vulnerable plaque in vivo but also effectively utilized the nano-enzyme activity of GPB to inhibit the AS progress by ROS scavenging and the following reduction of inflammation, apoptosis, and foam cells’ formation, providing a new avenue for the diagnosis and treatment of AS vulnerable plaque. Conclusion The fabricated multimodal imaging nanoparticles with ROS-scavenging ability provided a new avenue for the diagnosis and treatment of AS vulnerable plaques.