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At present, the output shaft of a permanent magnet spherical actuator (PMSA) is a rigid structure, which has the problems of small load weight ratio and high energy consumption. It is difficult to meet the application requirements of lightweight, high speed, and low energy consumption. In this paper, a PMSA is proposed as the driving motor for the rigid-flexible coupling system (R-FCS) of the robotic manipulator, and a flexible mechanical arm is used to replace the rigid output shaft of the PMSA to connect the hand claw to form a spherical joint. Firstly, the partial differential dynamics model of the robotic manipulator in the coordinate system is established based on the Hamilton method, and the R-FCS is constructed according to the momentum conservation equation combined with the rigid axis dynamics model of the PMSA. Then, a backstepping sliding mode controller (BSMC) is designed to form a closed-loop control system by selecting an appropriate nonlinear gain function to estimate the unknown disturbances of the system, and the stability of the controller is guaranteed by the Lyapunov theory. Finally, the simulation and experimental results verify that the R-FCS can achieve better trajectory tracking and provide an effective driving method for robotic manipulator spherical joint. [ABSTRACT FROM AUTHOR]

In order to deal with the modeling of uncertainty and external environment disturbance in the trajectory tracking system of 3 degrees of freedom permanent-magnet spherical actuator, a nonsingular terminal sliding mode control method with sliding perturbation observer is proposed in this article. First, a sliding perturbation observer, which can estimate compound disturbance only by feedback position signals, is proposed to reduce the uncertainty caused by angular velocity observation. Then, based on the sliding perturbation observer, a nonsingular terminal sliding mode control method is designed to satisfy the requirements of system nonsingularity, robustness, and control accuracy. The stability of the controller is proved by the Lyapunov theory. Finally, simulation and experimental results show that the proposed control method has excellent anti-disturbance performance, which provides an important reference for the future applications of permanent-magnet spherical actuators in aerospace and other industrial fields. [ABSTRACT FROM AUTHOR]

The inhibition of Type II angiotensin II receptor (AT2R) or BK2R (bradykinin type II receptor) stimulates basolateral Kir4.1/Kir5.1 in the distal convoluted tubule (DCT) and activates thiazide-sensitive NCC (Na-Cl cotransporter). The aim of the present study is to examine the role of AT2R and BK2R in mediating the effect of HK (high dietary K+) intake on the basolateral K+ channels, NCC, and renal K+ excretion. Feeding mice (male and female) with HK diet for overnight significantly decreased the basolateral K+ conductance, depolarized the DCT membrane, diminished the expression of pNCC (phosphorylated NCC) and tNCC (total NCC), and decreased thiazide-sensitive natriuresis. Overnight HK intake also increased the expression of cleaved ENaC-α and -γ subunits but had no effect on NKCC2 expression. Pretreatment of the mice (male and female) with PD123319 and HOE140 stimulated the expression of tNCC and pNCC, augmented hydrochlorothiazide-induced natriuresis, and increased the negativity of the DCT membrane. The deletion of Kir4.1 not only decreased the NCC activity but also abolished the stimulatory effect of PD123319 and HOE140 perfusion on NCC activity. Moreover, the effect of overnight HK loading on Kir4.1/Kir5.1 in the DCT and NCC expression/activity was compromised in the mice treated with AT2R/BK2R antagonists. Renal clearance study showed that inhibition of AT2R and BK2R impairs renal K+ excretion in response to overnight HK loading, and the mice pretreated with PD123319 and HOE140 were hyperkalemic during HK intake. We conclude that synergistic activation of AT2R and BK2R is required for the effect of overnight HK diet on Kir4.1/Kir5.1 in the DCT and NCC activity. [ABSTRACT FROM AUTHOR]

Recent studies have identified certain non‐coding RNAs (ncRNAs) as biomarkers of disease progression. Glioma is the most common primary intracranial cancer, with high mortality. Here, we developed a prognostic signature for prediction of overall survival (OS) of glioma patients by analyzing ncRNA expression profiles. We downloaded gene expression profiles of glioma patients along with their clinical information from the Gene Expression Omnibus and extracted ncRNA expression profiles via a microarray annotation file. Correlations between ncRNAs and glioma patients' OS were first evaluated through univariate Cox regression analysis and a permutation test, followed by random survival forest analysis for further screening of valuable ncRNA signatures. Prognostic signatures could be established as a risk score formula by including ncRNA signature expression values weighted by their estimated regression coefficients. Patients could be divided into high risk and low risk subgroups by using the median risk score as cutoff. As a result, glioma patients with a high risk score tended to have shorter OS than those with low risk scores, which was confirmed by analyzing another set of glioma patients in an independent dataset. Additionally, gene set enrichment analysis showed significant enrichment of cancer development‐related biological processes and pathways. Our study may provide further insights into the evaluation of glioma patients' prognosis. Through integrating univariate and multivariate Cox regression analysis of a glioma expression dataset from the Gene Expression Omnibus, we developed a prognostic model that contains three non‐coding RNAs, through which a risk score was allocated to each sample. Glioma patients with a high risk score tended to have shorter overall survival than those with a low risk score, which was confirmed using another set of glioma patients in an independent dataset. [ABSTRACT FROM AUTHOR]

Due to the nonlinear and strong coupling dynamic model of a direct-drive permanent magnet spherical motor (PMSM) dynamics system, an adaptive backstepping sliding mode controller is developed. Firstly, by using the second Lagrange equation and the Carden angle coordinate transformation, the PMSM rotor dynamic model is achieved. Secondly, the proposed approach effectively combines the design techniques of backstepping and the sliding mode control in order to restrain the effects of the external disturbance and parameter variations. Adaptive law of the external disturbance upper bound can be derived based on the Lyapunov-like design. Moreover, a novel reaching law is used to overcome the chattering phenomenon. Finally, simulation studies prove that the control scheme has high accuracy, rapid response and strong robustness. [ABSTRACT FROM AUTHOR]