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An extended state observer based fractional order sliding-mode control (ESO-FOSMC) is proposed in this study, with consideration of the strong nonlinear characteristics of a new electro-hydraulic servo system with iso-actuation balancing and positioning. By adopting the fractional order calculus theory, a fractional order proportional-integral-derivative (PID)based sliding mode surface was designed, which has the ability to obtain an equivalent positioning control with fractional order kinetic characteristics. By introducing the integral term into the sliding mode surface, it was found to be beneficial in reducing the steady-state errors, as well as improving the precision of the control system. Also, by using the fractional order calculus to replace the integral calculus, the form of the convergence is improved; the system transfer of energy is slowed down; and the chattering of the system is greatly weakened. The extended state observer was designed to observe the real-time disturbances, and also to generate the compensation control commands which are added to the FOSMC to achieve the dynamic compensation. By means of numerical simulations, the dynamic and static characteristics of the sliding mode control system were compared with those of the FOSMC and ESO-FOSMC. The experimental results show that the ESO-FOSMC system could effectively restrain the external disturbances and achieve higher control precision, as well as better control quantity without chattering. The semi-physical simulations based experimental tests also demonstrated that the proposed ESO-FOSMC outperformed the FOSMC in terms of system robustness and control precision, which could have a stable control of the gun system quickly and accurately.

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Dietary patterns and psychosocial factors, ubiquitous part of modern lifestyle, critically shape the gut microbiota and human health. However, it remains obscure how dietary and psychosocial inputs coordinately modulate the gut microbiota and host impact. Here, we show that dietary raffinose metabolism to fructose couples stress-induced gut microbial remodeling to intestinal stem cells (ISC) renewal and epithelial homeostasis. Chow diet (CD) and purified diet (PD) confer distinct vulnerability to gut epithelial injury, microbial alternation and ISC dysfunction in chronically restrained mice. CD preferably enriches Lactobacillus reuteri, and its colonization is sufficient to rescue stress-triggered epithelial injury. Mechanistically, dietary raffinose sustains Lactobacillus reuteri growth, which in turn metabolizes raffinose to fructose and thereby constituting a feedforward metabolic loop favoring ISC maintenance during stress. Fructose augments and engages glycolysis to fuel ISC proliferation. Our data reveal a diet-stress interplay that dictates microbial metabolism-shaped ISC turnover and is exploitable for alleviating gut disorders.

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Elevated kynurenine (Kyn) production from tryptophan (Trp) metabolism is a biomarker of immune dysregulation in depression, but its mechanistic contributions to the behavioral symptoms are poorly defined. In this study, Kyn was shown to be a metabolic regulator of proinflammatory monocytes that orchestrated peripheral immune activation and neuroinflammation in depressive mice. Kyn-induced depressive behavior was paralleled by brain infiltration of proinflammatory monocytes and astrocytic activation. Kyn enhanced chemokine (C-C motif) ligand-2-mediated chemotaxis of monocytes and their proinflammatory capability on cocultured astrocytes in vitro, which involved the activation of aryl hydrocarbon receptor (AhR) signaling. Kyn augmented, whereas pharmacological AhR blockade rescued, systemic inflammation-induced monocyte trafficking, neuroimmune disturbance, and depressive-like behavior in mice. The behavior-exacerbating effects of the Kyn-AhR axis were dampened with prior depletion of functional monocytes in the periphery. The findings in our study extend understanding of an immunologic effect of Kyn that links Trp metabolism and inflammatory signaling in depression pathology, with potential therapeutic implications for depressive disorders.-Zang, X., Zheng, X., Hou, Y., Hu, M., Wang, H., Bao, X., Zhou, F., Wang, G., Hao, H. Regulation of proinflammatory monocyte activation by the kynurenine-AhR axis underlies immunometabolic control of depressive behavior in mice.