Summary
This paper addresses the synchronization control problem of flexible telerobotics with actuator fault, input saturation, and asymmetrical time‐varying delays. A new adaptive antisaturation nonlinear fractional power proportional+damping fault‐tolerant control scheme is designed. With the new control algorithm, faster convergence rate and higher convergence precision can be guaranteed, as compared with the general proportion+damping control method. By choosing Lyapunov‐Krasovskii functional, it shows that the teleoperation system is stable under specific linear matrix inequality conditions. Thus, the allowable maximal transmission delay can be computed with the given controller‐design parameters. To validate the effectiveness of the proposed method, simulations on synchronization control system composed of 2 manipulators (master is rigid, and slave is flexible) are developed. Experiments on the PHANToM Premium 1.5A manipulators are also conducted and numerous experimental results are presented to show the superior performance of the proposed control scheme.
Potassium bromate (KBrO) is widely used as a food additive and is a major by-product of water disinfection. The aim of this study was to investigate the protective effects of fraction 4a of polysaccharides isolated from Lycium barbarum (LBP-4a) against renal damage induced by KBrO in rats and to determine the relevant mechanisms behind these effects. Male Wistar rats were divided into a normal control group, a KBrO control group, and LBP-4a(L) and LBP-4a(H) groups. With the exception of the normal control group, the rats in the other three groups were administered KBrO by intraperitoneal injection to induce renal damage. Before the induction of renal damage, rats in the LBP-4a(L) and LBP-4a(H) groups were pretreated with 50 mg per kg b.w. or 100 mg per kg b.w. LBP-4a, respectively, by intragastric administration. Clinical biochemical parameters and markers of oxidative damage were also determined. Treatment by administration of LBP-4a prior to challenge with KBrO prevented increases in the levels of nitrite, creatinine, urea nitrogen and uric acid in serum and increased the activities of antioxidant enzymes in kidney tissues. A comet assay and FCS results showed that pretreatment with LBP-4a also alleviated DNA damage and decreases in mitochondrial membrane potentials in renal cells. Histological studies further supported the above results and showed extensive renal damage in animals treated with KBrO and greatly reduced tissue injury in groups pretreated with LBP-4a. In conclusion, LBP-4a exhibited protective effects against renal damage induced by KBrO, and the mechanism was closely correlated with a reduction in levels of lipid peroxidation and an increase in the activities of antioxidant enzymes in kidney tissues, which alleviated DNA damage and increased mitochondrial membrane potentials in renal cells. These observations provide the background for the further development of LBP-4a as a protective agent for use in the treatment of renal damage.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.