Global asymptotic stability of a scalar delay Nicholson's blowflies equation in periodic environment

This paper is considered with a scalar delay Nicholson’s blowflies equation in periodic environment. By taking advantage of some novel differential inequality techniques and the fluctuation lemma, we set up the sharp condition to characterize the global asymptotic stability of positive periodic solutions on the addressed equation. The obtained results improve and supplement some existing ones in recent literature, and then give a more perfect answer to an open problem proposed by Berezansky et al. in [Appl. Math. Model. 34(2010), 1405–1417]. In particular, two numerical examples are provided to verify the reliability and feasibility of the theoretical findings

Game equilibrium based control analysis on the sustainable market structure of rare metal mineral resources – evidence from China

In rare metal mineral market, as a complex system, multiple decision-making among the stakeholders increases the complexity in its market structure and dynamic process. The unreasonable compensation pricing mechanism for the development of the rare metal mineral resources in China requires to be studied. Drawing on the methods of game theory model and chaos control analysis, this paper builds theoretical model of rare metal mineral market structure, corporating related parameters of rare metal in the game theory model, to conduct the chaotic nature and path analysis, expecting to solve the bottleneck problems that restrict the rare metal pricing and resource security and enhance the waste valorization for the sustainability. Specificly, a Cournot-Nash Equilibrium model is built to analyze the Cournot-equilibrium point, the stability of the Cournot Equilibrium point, the chaotic status, as well as the pattern to chaos of the game system in the rare metal mineral resource market, numerical simulation is used to verify the model. The conclusions facilitate the formulation of industrial economic policies and further improvement of managerial strategies to solve market problems

Noise Attenuation Estimation for Maximum Length Sequences in Deconvolution Process of Auditory Evoked Potentials

The use of maximum length sequence (m-sequence) has been found beneficial for recovering both linear and nonlinear components at rapid stimulation. Since m-sequence is fully characterized by a primitive polynomial of different orders, the selection of polynomial order can be problematic in practice. Usually, the m-sequence is repetitively delivered in a looped fashion. Ensemble averaging is carried out as the first step and followed by the cross-correlation analysis to deconvolve linear/nonlinear responses. According to the classical noise reduction property based on additive noise model, theoretical equations have been derived in measuring noise attenuation ratios (NARs) after the averaging and correlation processes in the present study. A computer simulation experiment was conducted to test the derived equations, and a nonlinear deconvolution experiment was also conducted using order 7 and 9 m-sequences to address this issue with real data. Both theoretical and experimental results show that the NAR is essentially independent of the m-sequence order and is decided by the total length of valid data, as well as stimulation rate. The present study offers a guideline for m-sequence selections, which can be used to estimate required recording time and signal-to-noise ratio in designing m-sequence experiments

Curcumin suppresses leukemia cell proliferation by downregulation of P13K/AKT/mTOR signalling pathway

Purpose: To investigate the effect of curcumin ester on the proliferation of leukemia cell lines in vitro. Methods: Changes in WEHI-3 and THP 1 cell viabilities were measured using Cell Counting Kit 8 (CCK 8). Analysis of cell cycle and determination of apoptosis were carried out using propidium iodide and Annexin V fluorescein isothiocyanate staining. Transmission electron microscopy was used for observing the presence of apoptotic features in cells. Results: Treatment with curcumin ester for 72 h caused significant reduction in the proliferation of WEHI-3 and THP 1 cells. Curcumin ester, at a dose of 50 µM, decreased the proliferations of WEHI-3 and THP 1 cells to 28 and 32 %, respectively. On exposure to curcumin ester for 72 h, cell cycle in WEHI-3 cells was arrested in G1/G0 phase. Curcumin ester at doses of 25, 30 and 50 µM enhanced apoptosis in WEHI-3 cells to 46, 58 and 64 %, respectively. Curcumin ester suppressed the levels of phosphoinositide 3 kinase (PI3K), protein kinase B (AKT) and mechanistic target of rapamycin (mTOR) protein and mRNA in WEHI-3 cells. In curcumin ester-treated WEHI-3 cells, the presence of apop¬totic bodies increased significantly and concentration-dependently. Conclusion: These results demonstrate that curcumin ester inhibits leukemia cell proliferation by inducing apoptosis and arresting cell cycle in G1/G0 phase, probably via suppression of PI3K, AKT and mTOR, and promotion of PTEN. Thus, curcumin ester has potentials for use in the development of an effective treatment strategy for leukemia

Poly[[diaqua­{N-[1-(3-pyrid­yl)ethyl­idene]-4H-1,2,4-triazol-4-amine}zinc(II)] bis­(perchlorate)]

In the title compound, {[Zn(C9H9N5)2(H2O)2](ClO4)2}n, the ZnII ion lies on an inversion center and is coordinated by two triazolyl N atoms and two pyridyl N atoms from four symmetry-related N-1-(3-pyrid­yl)ethyl­idene-4H-1,2,4-triazol-4-amine (L) ligands and two O atoms from coordinated water mol­ecules in a slightly distorted octa­hedral environment. Each L ligand bridges symmetry-related ZnII ions, forming a two-dimensional layer with a (4,4) grid. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds connect perchlorate counter-anions to the layers