Protective effect of vanillin in streptozotocin-induced diabetes in neonatal rats via attenuation of oxidative stress and inflammation

Purpose: To evaluate the antidiabetic activity of vanillin in streptozotocin (STZ)-induced diabetic rats.Methods: Diabetes was induced in 2-day old male pups by intraperitoneal (i.p.) administration of STZ (90 mg/kg). The pups were then randomly assigned to four groups: control group which received citrate buffer only in place of STZ; negative control group, i.e., diabetic group; and vanillin-treated groups which received vanillin (100 or 200 mg/kg, p.o.) continuously from the 6th week of age to the 10th week. The antidiabetic effect of vanillin was determined by measuring the serum levels of insulin, triglycerides and glucose in the diabetic rats. Oral glucose tolerance, kidney and liver function tests were also performed at the end of the protocol. Moreover, the oxidative stress and inflammatory cytokines in liver tissues, and histopathological changes in pancreatic tissues were assessed.Results: Vanillin treatment significantly decreased serum glucose and triglyceride levels and increased the level of insulin, when compared to the negative control group. There was higher insulin sensitivity in the vanillin-treated group than in the negative control group. In addition, vanillin improved liver and renal functions in STZ-induced diabetic neonatal rats. Hepatic oxidative stress and inflammatory mediators, as well as histopathological changes in pancreas were attenuated by vanillin treatment.Conclusion: These results reveal that vanillin attenuates hyperglycemia in STZ-induced neonatal diabetic rat model by decreasing oxidative stress and inflammatory cytokines. There, further studies are required to develop the anti-diabetic potentials of vanillin for clinical applications.Keywords: Vanillin, Streptozotocin, Diabetes, Oxidative stress, Insulin, Neonata

MUI-TARE: Multi-Agent Cooperative Exploration with Unknown Initial Position

Multi-agent exploration of a bounded 3D environment with unknown initial positions of agents is a challenging problem. It requires quickly exploring the environments as well as robustly merging the sub-maps built by the agents. We take the view that the existing approaches are either aggressive or conservative: Aggressive strategies merge two sub-maps built by different agents together when overlap is detected, which can lead to incorrect merging due to the false-positive detection of the overlap and is thus not robust. Conservative strategies direct one agent to revisit an excessive amount of the historical trajectory of another agent for verification before merging, which can lower the exploration efficiency due to the repeated exploration of the same space. To intelligently balance the robustness of sub-map merging and exploration efficiency, we develop a new approach for lidar-based multi-agent exploration, which can direct one agent to repeat another agent's trajectory in an \emph{adaptive} manner based on the quality indicator of the sub-map merging process. Additionally, our approach extends the recent single-agent hierarchical exploration strategy to multiple agents in a \emph{cooperative} manner by planning for agents with merged sub-maps together to further improve exploration efficiency. Our experiments show that our approach is up to 50\% more efficient than the baselines on average while merging sub-maps robustly.Comment: 8 pages, 8 figures, Submitted to IEEE RA

PyPose: A Library for Robot Learning with Physics-based Optimization

Deep learning has had remarkable success in robotic perception, but its data-centric nature suffers when it comes to generalizing to ever-changing environments. By contrast, physics-based optimization generalizes better, but it does not perform as well in complicated tasks due to the lack of high-level semantic information and the reliance on manual parametric tuning. To take advantage of these two complementary worlds, we present PyPose: a robotics-oriented, PyTorch-based library that combines deep perceptual models with physics-based optimization techniques. Our design goal for PyPose is to make it user-friendly, efficient, and interpretable with a tidy and well-organized architecture. Using an imperative style interface, it can be easily integrated into real-world robotic applications. Besides, it supports parallel computing of any order gradients of Lie groups and Lie algebras and $2^{\text{nd}}$-order optimizers, such as trust region methods. Experiments show that PyPose achieves 3-20$\times$ speedup in computation compared to state-of-the-art libraries. To boost future research, we provide concrete examples across several fields of robotics, including SLAM, inertial navigation, planning, and control

Risk assessment and dams – Recent developments and applications

Increasingly, society and standards require "risk-informed" decisions. The paper demonstrates the benefits of implementing reliability and risk concepts in dam engineering as a complement to conventional deterministic analyses. Reliability evaluations can range from qualitative estimates, to simple statistical evaluations, to full probabilistic modelling of the hazards and consequences for a system of dams. The paper gives an overview of basic concepts of reliability-based approaches and illustrates their use with three case studies. The paper discusses the strengths of reliability-based analyses and key issues such as tolerable and acceptable risk, the meaning of factor of safety, the targets for a margin of safety and the selection of characteristic value for analysis. Reliability-based approaches provide useful insight and complementary information. They enable the analysis of complex uncertainties in a systematic and more complete manner than deterministic analyses alone, both for the design of dams and for their safety evaluation during their lifetime. Reliability and risk-based approaches assist with preparing engineering recommendations and making decisions.publishedVersio

Effects of Porosity, Heat Input and Post-Weld Heat Treatment on the Microstructure and Mechanical Properties of TIG Welded Joints of AA6082-T6

Various heat input conditions and post-weld heat treatments were adopted to investigate the microstructure evolution and mechanical properties of tungsten inert gas (TIG) welded joints of AA6082-T6 with porosity defects. The results show that the fracture location is uncertain when an as-welded joint has porosities in the weld zone (WZ), and overaging in the heat-affected zone (HAZ) at the same time. When the fracture of the as-welded joint occurs in the HAZ, the total heat input has a linear relation with the tensile strength of the joint. An excess heat input induces the overgrowth of Mg2Si precipitates in HAZ and the coarsening of α-Al grains in WZ, resulting in a decrease in the microhardness of the corresponding areas. After artificial aging treatment, the tensile strength of the welded joint is increased by approximately 9–13% as compared to that of as-welded joint, and fracture also occurs in HAZ. In contrast, for solution treated and artificial aging treated joint, fracture occurs suddenly at the rising phase of the tensile curve due to porosity defects throughout the weld metal. Furthermore, the eutectic Si particles of WZ coarsen and spheroidize after solution treatment and artificial aging treatment, due to the diffusion of Si to the surface of the original Si phases when soaking at high temperature

Study in Wire Feedability-Related Properties of Al-5Mg Solid Wire Electrodes Bearing Zr for High-Speed Train

This work offers an analysis of the wire feedability-related properties of Al-5Mg solid wire electrodes bearing Zr. Effects of Zr content on microstructures and mechanical properties of the Al-5Mg alloys were studied. Experimental results have demonstrated that α-Al dendrites of the as-cast Al-5Mg alloy are refined, and the tensile strength, microhardness and roughness of the 1.2 mm wire electrode are improved with an appropriate addition of Zr. In addition, the tensile strength and elongation of the welded joints welded using Al-5Mg wire electrodes bearing Zr reach the maximum value when 0.12% Zr is added into the wire alloy. However, when excess Zr is added, α-Al phases of the wire alloy and welded joint are coarsened, and the mechanical properties are deteriorated. Moreover, the structure and principle of a novel apparatus, which can enhance the feedability of the wire electrode, are introduced and the apparatus can achieve the rough and fine adjustments of cast and helix of the wire electrode

Influence of Hydrogen Content on the Microstructure and Mechanical Properties of ER5183 Wires

This work focused on the influence of hydrogen content on the microstructure and mechanical properties of ER5183 Al-Mg-Mn alloy wires for aluminum alloy welding. The hydrogen content of the ER5183 wires was measured, the macroscopic and microscopic morphologies of fractures were observed as well as the microstructure of the wires, and the tensile strength of the wires was also tested and investigated. The experimental results demonstrated three typical irregular macroscopic fractures of the wires appeared during the drawing process when the hydrogen content exceeded 0.23 μg/g. In the meantime, the aggregated pores were observed in the microstructure of the ϕ5.2 mm wire with the hydrogen content of 0.38 μg/g. Such defects may become the origin of cracks in subsequent processing and tensile tests. Moreover, higher hydrogen content in the ϕ5.2 mm welding wire will bring obvious changes in the fracture surface, which are internal cracks and micropores replacing the original uniform and compact dimples. With the higher hydrogen content, the tensile strength and plastic strain rate of ϕ1.2 mm wires would decrease. At the same time, unstable crack propagation would occur during the process of plastic deformation, leading to fracture. Considering the mechanical properties and microstructure, the hydrogen content of the ER5183 wires should be controlled below 0.23 μg/g

Near-Optimal Control for Offshore Structures with Nonlinear Energy Sink Mechanisms

To improve the safety and reliability of offshore structures subject to wave loading, the active vibration control problem is always one of significant issues in the field of ocean engineering. This paper deals with the near–optimal control problem of offshore structures with a nonlinear energy sink (NES) mechanism. By taking the dominant vibration mode of the offshore structure with the NES into account, a nonlinear dynamic model of the steel–jacket structure subject to wave loading is presented first. Then, using the parameter perturbation approach to solve a nonlinear two–point boundary value problem, an NES–based optimal controller with the form of infinite series sum is presented to suppress the vibration of the offshore structure. Third, an iteration algorithm is provided to obtain the near–optimal controller. Simulation results demonstrate that the NES–based near–optimal controller can mitigate the oscillation amplitude of offshore structures significantly. Moreover, the NES–based optimal controller outperforms the one based on active tuned mass damper