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Endogenous CO is produced by heme in cells and is involved in various physiological processes. Carbon monoxide releasing molecules (CORMs) could deliver CO-controlled to biological systems. At present, most fluorescent probes used to detect CO or CORM have some problems, such as long response time and toxicity to biological systems. Therefore, this work reports a novel fluorescent probe (PNQ) that can detect CORM-3 real-time based on the coordination of the intramolecular electron-poor double bond and the reduction of nitro group by green and red fluorescence channels. A detail recognition mechanism is proposed. The probe enables ultra-fast detection of CORM-3 without the assistance of other substances and monitors CORM-3 concentrations at the cellular level. Significantly, PNQ is the first case that can detect the concentration of CORM-3 in endoplasmic reticulum and mitochondria based on different fluorescence emission and has the characteristics of spatial and temporal distribution. We believe that this probe has great potential for studying synergistic or antagonistic effects between organelles on CO released by CORM-3 and regulation. [Display omitted] • A new probe (PNQ) was developed for the detection CORM-3. • A new recognition mechanism was proposed for further understanding coordination chemistry. • PNQ achieves ultra-fast response to CORM-3 by two fluorescence channels in a time-dependent manner. • PNQ achieves multi-organelle targeting with temporal and spatial characteristics. [ABSTRACT FROM AUTHOR]

Rendezvous and docking (RVD) with a tumbling target is challenging. In this paper, a novel control scheme based on motion planning and pose (position and attitude) tracking is proposed to solve the pose control of a chaser docking with a tumbling target in the phase of close range rendezvous. Firstly, the current desired motion of the chaser is planned according to the motion of the target. In planning the desired motion, the "approach path constraint" is considered to avoid collisions between the chaser and the target, and the "field-of-view constraint" is considered to make sure the vision sensors on the chaser to obtain tight relative pose knowledge of the target with respect to the chaser. Then, the difference between the chaser's motion and the desired motion is gradually reduced by a pose tracking controller. This controller is based on the non-singular terminal sliding mode (NTSM) method to make the tracking error converge to zero in finite time. Since the chaser nearly moves along the desired motion and the motion is reasonable, (1) it could safely arrive at the docking port of the target with a suitable relative attitude, (2) it will be always suitably oriented to observe the target well, and (3) the magnitude of the needed control inputs are less than that in existing literatures. The numerical results demonstrate the above three advantages of the proposed method. [ABSTRACT FROM AUTHOR]

This paper studies the pose tracking control problem for satellite proximity operations between a target and a chaser satellite, by which we mean that the chaser is required to track a desired time-varying trajectory given in advance with respect to the target. Firstly, by consulting an adaptive sliding-mode control method in literature developed for a class of nonlinear uncertain systems, an effective pose tracking controller is obtained. This controller requires no information about the mass and inertia matrix of the chaser, and takes into account the gravitational acceleration, the gravity-gradient torque, the J 2 perturbing acceleration, and unknown bounded disturbance forces and torques. Then, an updated controller is proposed by combining the aforementioned controller and the unscented Kalman filter (UKF). This updated controller estimates the inertial parameters of the chaser through UKF, so it is of better adaptive ability to the initial estimation of the inertial parameters. Finally, numerical simulations are given to demonstrate the effectiveness of the proposed controllers. The simulation results show that the updated controller is more accurate. • An adaptive sliding-mode (ASM) controller is designed for pose tracking, and both unknown bounded disturbances and the uncertainty of the inertial property are considered. • The adaptive ability of the proposed method to the initial estimation of the inertial parameters is improved by combining ASM and UKF. • Our methods have a wider application and need less computing resource. [ABSTRACT FROM AUTHOR]

Abstract Capturing an uncontrolled space target is a tremendously challenging research topic. Target capture by a space robot can be well planned according to predicted motion of the target. In this paper, motion prediction of an uncontrolled space target is studied and a motion prediction algorithm is proposed. In the proposed algorithm, firstly a method for identifying the parameters of motion state and inertial property of the target is established; and then through substituting the identified parameters into the dynamic equations of the target, the motion of the target can be predicted as the solution of the equations. In the identification of the parameters, the unscented Kalman filter (UKF) is applied. In order to support the UKF, a method for estimating noise level of the observation data is developed, so our motion prediction algorithm is noise adaptive. A practical convergent criterion is also designed to determine the time when the estimated result of the UKF is accurate enough, such that the predicted motion is credible enough. After that, the accuracy of the prediction is further improved by an optimization method. In the end of this paper, numerical simulations are done to verify the validity of the proposed motion prediction algorithm. Simulation results indicate that the proposed algorithm is able to predict the motion of the target precisely. [ABSTRACT FROM AUTHOR]

In this work, a novel FRET-based fluorescent probe (named CBC) was developed to detect bisulfite with outstanding selectivity by ratiometric method. Probe CBC exhibited excellent sensitivity toward HSO 3 − within 1 equivalent. The cell imaging of CBC indicated that it could detect exogenous and endogenous bisulfite with excellent photostability and low cytotoxicity. What's more, probe CBC realized the lipid droplet targeting. Therefore, probe CBC has the capacity to be used as a biological tool to monitor the bisulfite changes in vivo. [Display omitted] • A novel ratiometric fluorescent probe CBC was developed to detect sulfur dioxide derivatives. • CBC had a large Stokes shift of 230 nm and 95.7% energy transfer efficiency. • CBC possessed good selectivity and sensitivity toward sulfur dioxide derivatives. • CBC achieved detection sulfur dioxide derivatives in living cells and targeted lipid droplets. [ABSTRACT FROM AUTHOR]

Capturing a non-cooperative space target is a tremendously challenging research topic. Effective acquisition of motion information of the space target is the premise to realize target capture. In this paper, motion prediction of a free-floating non-cooperative target in space is studied and a motion prediction algorithm is proposed. In order to predict the motion of the free-floating non-cooperative target, dynamic parameters of the target must be firstly identified (estimated), such as inertia, angular momentum and kinetic energy and so on; then the predicted motion of the target can be acquired by substituting these identified parameters into the Euler’s equations of the target. Accurate prediction needs precise identification. This paper presents an effective method to identify these dynamic parameters of a free-floating non-cooperative target. This method is based on two steps, (1) the rough estimation of the parameters is computed using the motion observation data to the target, and (2) the best estimation of the parameters is found by an optimization method. In the optimization problem, the objective function is based on the difference between the observed and the predicted motion, and the interior-point method (IPM) is chosen as the optimization algorithm, which starts at the rough estimate obtained in the first step and finds a global minimum to the objective function with the guidance of objective function’s gradient. So the speed of IPM searching for the global minimum is fast, and an accurate identification can be obtained in time. The numerical results show that the proposed motion prediction algorithm is able to predict the motion of the target. [ABSTRACT FROM AUTHOR]

Viscosity and sulfur dioxide levels are important factors to evaluate the changes of cell micro-environment because a series of diseases usually occur when they are abnormal. At present, dual-response probes that can detect both viscosity and sulfur dioxide are rare. Therefore, we developed a novel fluorescent probe CBN for simultaneous detection of sulfur dioxide and viscosity. Besides, probe CBN could target lysosome of which normal function will be disrupted by the abnormality of viscosity. Therefore, probe CBN has the potential to be served as an effective biological tool to monitor the intracellular micro-environment. [Display omitted] • A novel ratiometric fluorescent probe CBN was developed to detect sulfur dioxide derivatives and viscosity. • CBN had a large Stokes shift of 215 nm and 96.8% energy transfer efficiency. • CBN possessed good selectivity and sensitivity toward sulfur dioxide derivatives. • CBN achieved detection viscosity in living cells and targeted lysosome. [ABSTRACT FROM AUTHOR]

A novel fluorescent probe (cys-pH) based on intramolecular charge transfer (ICT) mechanism for pH detection targeting mitochondria was developed. cys-pH has excellent mitochondrial targeting, a suitable pKa (8.53), a good linear range in the pH range of 6.50–10.00, and a sensitive response to fluctuations in mitochondrial pH. cys-pH has been succeeded in applying to monitor the pH of mitochondria in living cells and the pH detection of water samples in environmental systems. In addition, pH test papers and standard colorimetric cards of cys-pH are prepared. We reasonably explained the double absorption peak of cys-pH UV–vis spectrum in the long wavelength region. [Display omitted] • A new fluorescent probe for detecting pH was designed by ICT mechanism. • Probe cys-pH can monitor pH in mitochondria. • Probe cys-pH has been applied in detecting pH in environmental water samples. • pH test papers and standard colorimetric cards were made by cys-pH. • The double absorption peak of UV–vis spectrum of cys-pH was explained reasonably. [ABSTRACT FROM AUTHOR]