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A series of symmetrical donor-acceptor-donor (D-A-D) chromophores bearing various electron-withdrawing groups, such as quinoxaline (Qx), benzo[g]quinoxaline (BQ), phenazine (Pz), benzo[b]phenazine (BP), thieno[3,4-b]pyrazine (TP), and thieno[3,4-b]quinoxaline (TQ), has been designed and synthesized. Intramolecular charge transfer (ICT) interactions can be found for all the chromophores due to the electron-withdrawing properties of the two imine nitrogens in the pyrazine ring and the electron-donating properties of the other two amine nitrogens in the two triphenylamines. Upon the fusion of either benzene or thiophene ring on the pyrazine acceptor unit, the ICT interactions are strengthened, which results in the bathochromically shifted ICT band. Moreover, the thiophene ring is superior to the benzene ring in enlarging the ICT interaction and expanding the absorption spectrum. Typically, when a thiophene ring is fused on the Qx unit in DQxD, a near-infrared dye is realized in simple chromophore DTQD, which displays the maximum absorption wavelength at 716 nm with the threshold over 900 nm. This is probably due to the enhanced charge density on the acceptor moiety and better orbital overlap, as revealed by theoretical calculation. These results suggest that extending the conjugation of a pyrazine acceptor in an orthogonal direction to the D-A-D backbone can dramatically improve the ICT interactions.

Oscillatory activity plays a critical role in regulating biological processes at levels ranging from subcellular, cellular, and network to the whole organism, and often involves a large number of interacting elements. We shed light on this issue by introducing a novel approach called partial Granger causality to reliably reveal interaction patterns in multivariate data with exogenous inputs and latent variables in the frequency domain. The method is extensively tested with toy models, and successfully applied to experimental datasets, including (1) gene microarray data of HeLa cell cycle; (2) in vivo multi-electrode array (MEA) local field potentials (LFPs) recorded from the inferotemporal cortex of a sheep; and (3) in vivo LFPs recorded from distributed sites in the right hemisphere of a macaque monkey.

In this paper, a new discrete reaching law with improved quasi-sliding-mode domain (QSMD) is proposed and a sliding-mode controller is designed for discrete-time systems with uncertainties. By redefining the change rate as the second order difference of the system uncertainties and adopting the continuous approximate function, smaller width of the QSMD can be guaranteed. Moreover, the QSMD of the proposed reaching law is obtained and the system dynamics in and out the QSMD are theoretically analyzed. Perturbation estimation technique is employed to estimate the unknown uncertainties. Thus, no prior knowledge of the uncertainty bound is required. Both numerical simulations and experimental results on a piezoelectric actuator are presented to demonstrate the performance of the proposed method.Index Terms-Continuous approximate function, discrete-time sliding-mode control (DSMC), reaching law, second order difference.

BackgroundCurcumin (diferuloylmethane) has chemopreventive and therapeutic properties against many types of tumors, both in vitro and in vivo. Previous reports have shown that curcumin exhibits anti‐invasive activities, but the mechanisms remain largely unclear.MethodsIn this study, both microRNA (miRNA) and messenger RNA (mRNA) expression profiles were used to characterize the anti‐metastasis mechanisms of curcumin in human non‐small cell lung cancer A549 cell line.ResultsMicroarray analysis revealed that 36 miRNAs were differentially expressed between the curcumin‐treated and control groups. miR‐330‐5p exhibited maximum upregulation, while miR‐25‐5p exhibited maximum downregulation in the curcumin treatment group. mRNA expression profiles and functional analysis indicated that 226 differentially expressed mRNAs belonged to different functional categories. Significant pathway analysis showed that mitogen‐activated protein kinase, transforming growth factor‐β, and Wnt signaling pathways were significantly downregulated. At the same time, axon guidance, glioma, and ErbB tyrosine kinase receptor signaling pathways were significantly upregulated. We constructed a miRNA gene network that contributed to the curcumin inhibition of metastasis in lung cancer cells. let‐7a‐3p, miR‐1262, miR‐499a‐5p, miR‐1276, miR‐331‐5p, and miR‐330‐5p were identified as key microRNA regulators in the network. Finally, using miR‐330‐5p as an example, we confirmed the role of miR‐330‐5p in mediating the anti‐migration effect of curcumin, suggesting the importance of miRNAs in the regulation of curcumin biological activity.ConclusionOur findings provide new insights into the anti‐metastasis mechanism of curcumin in lung cancer.

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