GyroWheel is an innovative device that combines the actuating capabilities of a control moment gyro with the rate sensing capabilities of a tuned rotor gyro by using a spinning flex-gimbal system. However, in the process of the ground test, the existence of aerodynamic disturbance is inevitable, which hinders the improvement of the specification performance and control accuracy. A vacuum tank test is a possible candidate but is sometimes unrealistic due to the substantial increase in costs and complexity involved. In this paper, the aerodynamic drag problem with respect to the 3-DOF flex-gimbal GyroWheel system is investigated by simulation analysis and experimental verification. Concretely, the angular momentum envelope property of the spinning rotor system is studied and its integral dynamical model is deduced based on the physical configuration of the GyroWheel system with an appropriately defined coordinate system. In the sequel, the fluid numerical model is established and the model geometries are checked with FLUENT software. According to the diversity and time-varying properties of the rotor motions in three-dimensions, the airflow field around the GyroWheel rotor is analyzed by simulation with respect to its varying angular velocity and tilt angle. The IPC-based experimental platform is introduced, and the properties of aerodynamic drag in the ground test condition are obtained through comparing the simulation with experimental results. Full article

This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H₂O₂) in glutathione peroxidase-1 (gpx-1^−/−) and catalase (catalase^−/−) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1^−/− displayed significantly higher hepatic H₂O₂ levels than catalase^−/− compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1^−/− mice. Alcohol increased H₂O₂ production in catalase^−/− and wild-type, but not gpx-1^−/−, mice. Hepcidin expression was inhibited in alcohol-fed catalase^−/− and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1^−/− mice. Gpx-1^−/− mice also displayed higher level of basal liver CHOP protein expression than catalase^−/− mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1^−/− mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1^−/− mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H₂O₂ inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H₂O_2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH. Full article