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This article addresses the optimal tracking control problem with prescribed performance for uncertain nonlinear systems subject to input constraint and unknown disturbances. First, a fixed‐time monotonic convergence function is introduced to restrain tracking error, and a nonlinear mapping technique is employed to transform the constrained error into an unconstrained variable, then the fixed‐time output tracking issue is boiled down to the boundedness problem of the transformed variable. With the aid of a nonquadratic cost function, the input constraint is encoded into the optimization problem. To solve the unknown disturbances, an auxiliary system and an auxiliary disturbance policy are constructed, and the optimal control problem is formulated as a two‐player zero‐sum game. Moreover, a Hamilton–Jacobi–Isaacs (HJI) equation associated with this nonquadratic zero‐sum game is established to give the optimal control and the worst‐case disturbance policy solution. Subsequently, to avoid using knowledge of the system dynamics, three neural network approximators, namely, actor, critic, and disturbance, which are tuned online and simultaneously for approximating the solution of HJI, are constructed based on the integral reinforcement learning algorithm. Theoretical analysis shows that the reconstructed error system states and the weight estimation errors are semi‐globally uniformly ultimately bounded. Finally, the simulation study further tests the availability of the proposed control strategy. [ABSTRACT FROM AUTHOR]

Furthermore, the result of FE-1 test will not be confounded by exogenous pancreatic enzymes.[25] The FE-1 test can easily be performed and is suitable for the screening and the long-term follow-up of the patients with PEI. PERT is the first-line therapy for PEI of all causes by supplementing pancreatin during meals, thereby promoting the digestion of nutrients, relieving the digestive symptoms, and improving the patient's quality of life.[[35]] After a comprehensive evaluation for underlying diseases, clinical symptoms, nutritional status, and pancreatic exocrine function, patients with clinically definite or suspected PEI can be treated with PERT.[1] Pancreatic enzyme replacement therapy in patients with exocrine pancreatic insufficiency due to chronic pancreatitis: a 1-year disease management study on symptom control and quality of life. [Extracted from the article]

Osteoarthritis (OA) is characterized as the degeneration and destruction of articular cartilage. In recent decades, leonurine (LN), the main active component in medical and edible dual purpose plant Herba Leonuri, has been shown associated with potent anti‐inflammatory effects in several diseases. In the current study, we examined the protective effects of LN in the inhibition of OA development as well as its underlying mechanism both in vitro and in vivo experiments. In vitro, interleukin‐1 beta (IL‐1β) induced over‐production of prostaglandin E2, nitric oxide, inducible nitric oxide synthase, cyclooxygenase‐2, interleukin‐6 and tumor necrosis factor alpha were all inhibited significantly by the pretreatment of LN at a dose‐dependent manner (5, 10, and 20 µM). Moreover, the expression of thrombospondin motifs 5 (ADAMTS5) and metalloproteinase 13 (MMP13) was downregulated by LN. All these changes led to the IL‐1β induced degradation of extracellular matrix. Mechanistically, the LN suppressed IL‐1β induced activation of the PI3K/Akt/NF‐κB signaling pathway cascades. Meanwhile, it was also demonstrated in our molecular docking studies that LN had strong binding abilities to PI3K. In addition, LN was observed exerting protective effects in a surgical induced model of OA. To sum up, this study indicated LN could be applied as a promising therapeutic agent in the treatment of OA. Inhibition of PI3K/Akt/NF‐κB signaling with leonurine for ameliorating the progression of osteoarthritis: in vitro and in vivo studies [ABSTRACT FROM AUTHOR]

PURPOSE The aim of this study was to evaluate the serum levels of retinoic acid (RA), an active form of vitamin A, in postmenopausal women with hip fractures from Zhengzhou, China. METHODS: This was a case‐control study from the Affiliated Hospital of Zhengzhou University. Serum samples were drawn from 375 postmenopausal women who were diagnosed as having hip fracture and 750 matched controls without fracture. Serum RA levels were evaluated as both a continuous variable and a categorical variable in quintiles. RESULTS: The results showed that the serum levels of RA were significantly (P =.039) higher in patients with hip fracture compared with controls. In univariate and multivariate logistic regression analysis, for each 1 ng/mL increase of serum level of RA, the unadjusted and adjusted risk of hip fracture would be increased by 5% (odds ratio [OR] = 1.05; 95% confidence interval [CI] = 1.00‐1.10; P =.035) and 2% (OR = 1.02; 95% CI = 0.95‐1.11; P =.096), respectively. In multivariate models comparing the fifth with the third quintiles of RA, the RA was associated with hip fracture, and adjusted risk of hip fracture would be increased by 52% (OR = 1.52; 95% CI = 1.13‐1.42; P =.011). CONCLUSIONS: The results of our study suggest that subclinical higher levels of RA may increase the risk of hip fracture in postmenopausal women, particularly among the top quintile of serum RA. J Am Geriatr Soc 67:336–341, 2019. [ABSTRACT FROM AUTHOR]

isolation, structure determination and cytotoxicity of three new metabolites, asperfumigatin (I), isochaetominine (II), and 8-O-methylasterric acid (III) along with nineteen known metabolites [ABSTRACT FROM AUTHOR]