ABSTRACT
The aero ball joint is pivotal in aircraft duct systems due to its favorable properties, including displacement compensation and flexibility. In the stress assessment of air ducts, ball joints are usually simplified by using "Joints" connections to reduce the convergence problems caused by non-linearity, which requires a high degree of accuracy in the characteristic parameters of the ball joint. Accordingly, this paper builds a high temperature and pressure fatigue test platform to investigate the bending characteristics of the ball joint at different temperatures and pressures and points out the limitations of the current method. Then, a method combining finite element analysis (FEA) and the BP neural network is proposed to obtain the characteristic parameters of the ball joint. The results showed that the bending process of the ball joint tended to have two typically different stiffness properties, which were high rigidity and low rigidity. The bending characteristics were strongly influenced by pressure, but less influenced by temperature. The existing test platform increased the force reaction at the contact areas of the ball joint, resulting in errors in the measurement of characteristic parameters. The BP neural network prediction method could effectively alter the ball joint properties and reduce errors.
ABSTRACT
BACKGROUND: Traumatic brain injury (TBI) is posing serious health challenges for people across the globe due to high morbidity and mortality. However, none of the agents prevents or limits the damage caused by TBI because of its multifactorial etiology. Thus, the discovery of novel agents which can act via several pathways could serve the purpose and afford favorable consequence against TBI. Therefore, in the present article, we intended to investigate the protective effect of rhamnazin (RMZ), a dimethoxyflavone against experimentally induced TBI in mice. METHODS: The effect of RMZ was investigated on cerebral edema and grip test score after induction of experimental brain injury in rats. The effect of RMZ was also investigated on neuronal degeneration in brain tissues of the experimental mice via Nissl staining and flow cytometry analysis. The expression of Bax and Bcl-2 was also quantified using Western blot analysis. The level of inflammatory cytokines (TNF-α and IL-1ß) and oxidative stress markers (malondialdehyde, superoxide dismutase, and glutathione peroxidase) was also determined using enzyme-linked immunosorbent assay. RESULTS: RMZ showed a significant reduction in edema and improved grip strength. It also prevented neuronal degeneration via inhibition of neuronal apoptosis as shown by flow cytometry analysis. RMZ showed an antiapoptotic effect via reduction of Bax and increased the expression of Bcl-2 in Western blot analysis. It also showed to inhibit oxidative stress and inflammation compared to the TBI group. CONCLUSION: Collectively, our study is first to demonstrate the protective effect of RMZ against experimentally induced TBI in rats.
