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Particulate matter 2.5 (PM2.5), a component of atmospheric particulate matter, leads to changes in gene expression and cellular functions. Epidemiological evidence confirms that PM2.5 has a positive correlation with lung injury. However, the molecular mechanisms involved remain poorly understood, and preventive methods are needed. In the present study, with human bronchial epithelial (HBE) cells in culture, we showed that low concentrations of PM2.5 resulted in acceleration of the G1/S transition and cell proliferation. Consistent with these effects, expression of the pro‐inflammatory factor interleukin‐6 (IL‐6) was elevated in HBE cells exposed to PM2.5. Accordingly, signal transducer and activator of transcription 3 (STAT3) was activated, which down‐regulated expression of cyclin D1. In addition, PM2.5 exposure led to higher levels of miR‐21, and there was a reciprocal loop between miR‐21 and STAT3. For HBE cells, tanshinone IIA (Tan IIA) reversed the PM2.5‐induced cell cycle alteration and cell proliferation, and reduced the expression of cytokines (IL‐6, STAT3, and miR‐21). These results show that, for HBE cells, Tan IIA attenuates the PM2.5‐induced G1/S alteration and cell proliferation, and indicate that it has potential clinical application for PM2.5‐induced respiratory injuries. [ABSTRACT FROM AUTHOR]

Production of hydroxyl radicals (•OH) upon the oxidation of solid Fe(II) by O2 or H2O2 in soils and sediments has been confirmed, which benefits in situ remediation of contaminants. However, Fe(III) reduction by H2O2 is rate-limiting. Accelerating the Fe(III)/Fe(II) cycle could improve the efficiency of remediation. This study intended to use hydroxylamine to promote Fe(III)/Fe(II) cycle during 100 g/L soil oxidation by H2O2 for phenol degradation. The removal of phenol was 76% in 3 h during soil oxidation with 1 mM H2O2 in the presence of 1 mM hydroxylamine but was negligible in the absence of hydroxylamine. Fe(III) in the soil was reduced to 0.21 mM Fe(II) by 1 mM hydroxylamine in 30 min. The accelerated cycle of Fe(III)/Fe(II) in the soil by hydroxylamine could effectively decompose H2O2 to produced •OH, which was responsible for the effective enhancement of phenol degradation during soil oxidation. Under the conditions of 1 mM H2O2 and 100 g/L soil, the pseudo-first-order kinetic constant of phenol degradation increased proportionally from 0.0453 to 0.0844 min−1 with the increase of hydroxylamine concentrations from 0.5 to 1 mM. The kinetic constant also increased from 0.0041 to 0.0111 min−1 with H2O2 concentration increased from 0.5 to 2 mM, while it decreased from 0.0100 to 0.0051 min−1 with soil dosage increased from 20 to 200 g/L. In addition, column experiments showed that phenol (10 mg/L) degradation ratio kept at about 48.7% with feeding 2 mM hydroxylamine and 2 mM H2O2 at 0.025 PV/min. Column experiments suggested an optional application of hydroxylamine and H2O2 for in situ remediation. The output of this study provides guidance and optional strategies to enhance contaminant degradation during soil oxidation. [ABSTRACT FROM AUTHOR]

This paper studies the full‐state formation control problem of multiple nonholonomic unicycle vehicles. Firstly, the formation error model is transformed into standard nonholonomic chained form, including orientation and position error subsystems. For orientation subsystem, an angular velocity control law is designed to be a cooperative term plus an exponential decay function of time, ensuring orientations reach an agreement on a common value. For position error subsystem, a time‐varying output‐like variable is carefully constructed to ensure a stable zero dynamics, that is, the consensus of these output variables guarantees position formation, overcoming the intrinsic underactuated control difficulty. Then, a linear velocity control law is derived to realize consensus of outputs. It is proved that the proposed distributed time‐varying controller is capable of steering the vehicles to globally exponentially make into desired geometric position shape with the same orientations and vanishing velocities, provided that the communication topology is directed and having a spanning tree. The calculated convergence rates are shown dependent on controller coefficients; thus, the controller is modified to additionally reach a prescribed rate of convergence by redesigning conditions of controller parameters. Finally, two numerical simulations are implemented for five unicycle vehicles, demonstrating the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

This paper investigates how to design controllers to stabilize the underactuated surface vessel to desired constant location and orientation with vanishing velocities. The first control law is designed as a smooth function of position and orientation errors without using model parameters, where a gain is made time‐varying to get over the nonholonomic constraint on model. Skew‐symmetric and damping terms in model are exploited to help construct two particular Lyapunov functions, and Barbalat's lemma are combined to verify the global uniform asymptotic convergence of errors and velocities. Then, the second and the third control laws are devised as the forms of the first controller plus velocity feedbacks and can achieve the same stability as the first one but have a weaker gain condition. All the three controllers are robust to model parameters due to their absence in controllers and only require three model parameters' upper/lower bounds, decreasing the identification workload greatly. Moreover, they are the first smooth ones capable of achieving global uniform asymptotic full‐state stabilization control of vessel with unknown model parameters. Effectiveness of the proposed controllers is demonstrated by numerical simulations. [ABSTRACT FROM AUTHOR]

This paper investigates the leaderless consensus control problem of high-order nonholonomic chained systems. Based on the relationship between state and consensus error, a novel Lyapunov function is defined and is proved positive definite and radially unbounded. The first control law is constructed to make the Lyapunov function non-increasing. The Lyapunov method, graph theory and LaSalle invariance principle are applied to analyse system stability, where some skillful mathematical calculations are conducted to overcome the difficulties caused by nonholonomic constraint and high-order structure, and the explicit expression and the conditions of control parameter matrix are calculated. Then, the second control law is designed by extending the results to the input saturation case. Both of the two controllers are smooth, time-invariant, static, distributed, and able to achieve global asymptotic consensus of nonholonomic chained systems over connected undirected graph. Numerical simulation examples are implemented to demonstrate the effectiveness of the proposed control schemes. [ABSTRACT FROM AUTHOR]