Research on a combinatorial control method for coaxial rotor aircraft based on sliding mode

Aiming at the position and attitude tracking of coaxial rotor aircraft(CRA),this paper proposes a combinatorial control method of sliding mode control(SMC)coupled with proportional-integralderivative control(PIDC).Considering the complete description of flight dynamics,aerodynamics and airflow interference,the dynamical model of CRA is established.The dynamical model is simplified according to the actual flight,then the simplified dynamical model is divided into two subsystems:a fully-actuated subsystem and an under-actuated subsystem.The controller of the fully-actuated subsystem consists of a SMC controller coupled with a rate bounded PIDC controller,while the controller of the under-actuated subsystem is composed of a SMC controller.The sliding manifold is defined by combining the position and velocity tracking errors of the state variables for each subsystem.Lyapunov stability theory is used to verify the stability of the sliding mode controller,which ensures that all state trajectories of the system can reach and stay on the sliding mode surface,the uncertainty and external interference of the model are compensated.Simulation and experiment compared with the conventional PIDC are carried out,the results demonstrate the effectiveness and the robustness of the proposed control method of this paper.

Structural and Functional Changes of Immune System in Aging Mouse Induced by D-Galactose

Objective To investigate the role of D-galactose, especially in the structural and functional changes of the immune system in aging. Methods Serum levels of advanced glycation end-products （AGE） were determined by ELISA method. Ultra-structures of thymus and spleen were detected by transmission electron microscopy. MTT method was used to determine the lymphocyte proliferation. IL-2 activity was determined by bioassay. Northern blot was used to detect the IL-2 mRNA levels. Results Serum AGE levels of D-galactose- （P〈0.01） and AGE-treated （P〈0.05） mice （n=8） were increased significantly. The ultra-structures of thymus and spleen in D-galactose- and AGE-treated mice showed regressive changes similar to those in the aged control group. The lymphocyte mitogenesis and IL-2 activity of spleen were also decreased significantly （P〈0.01, n=8）. The change of IL-2 activity shown by Northern blot resulted from the change of mRNA expression. The AGE plus aminoguanidine group, however, showed no significant change in these parameters in comparison with the young control group （P〈0.01 or P〈0.05, n=8）. Conclusion D-galactose and AGE lead to a mimic regression change of aging in the immune system in vivo.

Serum magnesium level as a predictor of acute kidney injury in patients with acute pancreatitis

BACKGROUND Decreased serum magnesium(Mg2+)is commonly seen in critically ill patients.Hypomagnesemia is significantly more frequent in patients with severe acute pancreatitis.Acute kidney injury(AKI)in patients with acute pancreatitis(AP)is associated with an extremely high mortality.The association underlying serum Mg2+and AKI in AP has not been elucidated.AIM To explore the association between serum Mg2+on admission and AKI in patients with AP.METHODS A retrospective observational study was conducted in a cohort of patients(n=233)with AP without any renal injury before admission to our center from August 2015 to February 2019.Demographic characteristics on admission,severity score,laboratory values and in-hospital mortality were compared between patients with and without AKI.RESULTS A total of 233 patients were included for analysis,including 85 with AKI.Compared to patients without AKI,serum Mg2+level was significantly lower in patients with AKI at admission[OR=6.070,95%CI:3.374-10.921,P<0.001].Multivariate logistic analysis showed that lower serum Mg2+was an independent risk factor for AKI[OR=8.47,95%CI:3.02-23.72,P<0.001].CONCLUSION Our analysis indicates that serum Mg2+level at admission is independently associated with the development of AKI in patients with AP and may be a potential prognostic factor.

Research on DSO vision positioning technology based on binocular stereo panoramic vision system

In the visual positioning of Unmanned Ground Vehicle(UGV),the visual odometer based on direct sparse method(DSO) has the advantages of small amount of calculation,high real-time performance and high robustness,so it is more widely used than the visual odometer based on feature point method.Ordinary vision sensors have a narrower viewing angle than panoramic vision sensors,and there are fewer road signs in a single frame of image,resulting in poor road sign tracking and positioning capabilities,and severely restricting the development of visual odometry.Based on these considerations,this paper proposes a binocular stereo panoramic vision positioning algorithm based on extended DSO,which can solve these problems well.The experimental results show that the binocular stereo panoramic vision positioning algorithm based on the extended DSO can directly obtain the panoramic depth image around the UGV,which greatly improves the accuracy and robustness of the visual positioning compared with other ordinary visual odometers.It will have widely application prospects in the UGV field in the future.

Capture and Identification of Dual Specificity Mitogen-Activated Protein Kinase Kinase 7 as a Direct Proteomic Target of Berberine to Affect the c-JunN-Terminal Kinase Pathway

Seven photoaffinity-based and sixteen biotin-based berberine(BBR)probes were constructed and screened for their effects on c-Jun N-terminal protein kinases(JNK)phosphorylation(p-JNK)suppression at the cellular level.Taking active-photoaffinity probe 7c as a chemical tool,we first identified mitogen-activated protein kinase 7(MAP2K7),an upstream protein on the JNK/stress activated protein kinase(SAPK)pathway,as a direct proteomic target of BBR using activity-based protein profiling(ABPP)and other chemical proteomic techniques.Furthermore,BBR’s inhibitory effect on p-JNK was significantly attenuated in both the MAP2K7-knockdown and models,indicating a MAP2K7-dependent inhibition on the JNK signaling pathway.For the first time,we demonstrate the unique mechanism of BBR that directly targets MAP2K7 to inhibit p-JNK rather than JNK activity with the advantages of multiple activities and a good safety profile.