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Twenty‐one new coumarin Mannich base derivatives (11a‐u) were synthesized, which exhibited antiproliferation activities in HepG2 (liver cancer), A549 (lung cancer), MCF‐7 (breast cancer), and HT‐29 (colon cancer). Most of the target compounds showed the most potent activity against HepG2 cells compared with other cancer cells, compound 11g showed the strongest antiproliferative activity (2.10 μM) against HepG2, even superior to the positive control drug 5‐FU(5.49 μM). The nitric oxide (NO) release of all compounds in HepG2 cells was determined, of which compound 11g showed high levels of NO release (10.8 μM). Notably, the solubility of compound 11g increased 13‐fold compared with the lead 8. The preliminary cytotoxicity studies suggest that 11g had little effect on LO2 cells(normal liver cells, >50 μM). The effect of compound 11g on the apoptosis of HepG2 cells was also studied, and the results showed that the induction effect of compound 11g on apoptosis is a concentration‐dependent manner. Our results indicate that compound 11g might be a promising lead for further studies. [ABSTRACT FROM AUTHOR]

An indoor positioning system, with ultra-high frequency radio frequency identification based on phase difference (PD), is presented in this paper. Several groups of phases are obtained by setting reader's different transmitting frequency to reduce the phase ambiguity. Two positioning algorithms are proposed with rough PDs, which are pattern matching based on PD correction and machine learning based on without PD correction. The experiments of two methods, in which machine learning gets a better positioning precision of 0.43 m, are also presented and discussed. [ABSTRACT FROM AUTHOR]

A novel model-based methodology to fault diagnosis (FD) of nonlinear hydraulic drive systems is presented in this paper. Due to its linear dependence upon parameters, a second-truncated Volterra nonlinear model is first used to characterize such systems. The versatile order-recursive estimation scheme is employed to determine the values of parameters in the Volterra model. The scheme also avoids separate determination of the model order; thus, the complexity of the search process is reduced. Next, it is shown that the estimated parameters, representing different states of the system, normal as well as faulty conditions, can be used to detect and isolate system faults in a geometric domain. Very promising results are exhibited via simulations as well as laboratory experiments. It is concluded that the developed parametric FD technique has potential to provide efficient condition monitoring and/or preventive maintenance in hydraulic actuator circuits. Index Terms--Electrohydraulic actuators, fault diagnosis, feature extraction, geometric projection scheme, parameter estimation, Volterra nonlinear models.

This paper develops a novel identification methodology for nonminimum-phase autoregressive moving average (ARMA) models of which the models' orders are not given. It is based on the third-order statistics of the given noisy output observations and assumed input random sequences. The semiblind identification approach is thereby named. By the order-recursive technique, the model orders and parameters can be determined simultaneously by minimizing well-defined cost functions. At each updated order, the AR and MA parameters are estimated without computing the residual time series (RTS), with the result of decreasing the computational complexity and memory consumption. Effects of the AR estimation error on the MA parameters estimation are also reduced. Theoretical statements and simulations results, together with practical application to the train vibration signals' modeling, illustrate that the method provides accurate estimates of unknown linear models, despite the output measurements being corrupted by arbitrary Gaussian noises of unknown pdf. Index Terms - Nonminimum-phase ARMA models, order-recursive methods, semiblind identification, third-order cumulants.