Apoptosis in BEL-7402 cells induced by ruthenium(II) complexes through a ROS-mediated mitochondrial pathway

Three Ru(II) polypyridyl complexes [Ru(dmb)₂(HMSPIP)](ClO₄)₂ (1), [Ru(phen)₂(HMSPIP)](ClO₄)₂ (2) and [Ru(dmp)₂(HMSPIP)](ClO₄)₂ (3) were synthesized and characterized. The cytotoxicity in vitro, apoptosis, cell cycle arrest, reactive oxygen species and mitochondrial membrane potential were assayed. The IC₅₀ values of complexes 1, 2 and 3 toward BEL-7402, A549, MG-63 and SK-BR-3 cell lines ranged from 10.9 ± 1.6 to 42.0 ± 3.4 μM. Complexes 1, 2 and 3 can effectively induce apoptosis and inhibit the growth of BEL-7402 cells at the G2/M phase. These complexes can enhance the level of reactive oxygen species and induce decrease in the mitochondrial membrane potential. Additionally, complex 2 can down-regulate the expression of antiapoptotic protein of Bcl-2 protein and up-regulate the levels of proapoptotic protein Bim in BEL-7402 cells.     

Investigation of quasi lateral-field-excitation on (yxl)-17° LiNbO3 single crystal

Quasi lateral-field-excitation (LFE) on LiNbO₃ crystal is investigated both theoretically and experimentally. It is found that when the driving electric field direction is parallel to the crystallographic X-axis of the piezoelectric substrate, (yxl)-17° LiNbO₃ LFE bulk acoustic wave devices work on quasi-LFE mode. The experimental results agreed with the theoretical prediction well. The results provide the cut of LiNbO₃ crystal for quasi-LFE bulk acoustic wave devices, which is important for designing high performance LFE sensors on LiNbO₃ substrates.     

An explicit solution of the large deformation of a cantilever beam under point load at the free tip

The large deformation of a cantilever beam under point load at the free tip is investigated by an analytic method, namely the homotopy analysis method (HAM). The explicit analytic formulas for the rotation angle at the free tip are given, which provide a convenient and straightforward approach to calculate the vertical and horizontal displacements of a cantilever beam with large deformation. These explicit formulas are valid for most practical problems, thus providing a useful reference for engineering applications. The corresponding Mathematica code is given in the Appendix.     

Controllable and flexible cellular network for virus cell-to-cell spread

Cellular networks were constructed based on PEG modification and soft lithography, in which cell numbers and spatial distributions can be controlled. A micro-injector was combined with cellular networks to fix virus induced plaque and virus spread direction, by which virus cell-to-cell spread can be distinguished from cell-free spread.     

ELECTRICALLY FORCED THICKNESS-SHEAR VIBRATIONS OF QUARTZ PLATE WITH NONLINEAR COUPLING TO EXTENSION

We study electrically forced nonlinear thickness-shear vibrations of a quartz plate resonator with relatively large amplitude. It is shown that thickness-shear is nonlinearly coupled to extension due to the well-known Poynting effect in nonlinear elasticity. This coupling is relatively strong when the resonant frequency of the extensional mode is about twice the resonant frequency of the thickness-shear mode. This happens when the plate length/thickness ratio assumes certain values. With this nonlinear coupling, the thickness-shear motion is no longer sinusoidal. Coupling to extension also affects energy trapping which is related to device mounting. When damping is 0.01, nonlinear coupling causes a frequency shift of the order of 10^-6 which is not insignificant,and an amplitude change of the order of 10^-8. The effects are expected to be stronger under real damping of 10^-5 or larger. To avoid nonlinear coupling to extension, certain values of the aspect ratio of the plate should be avoided.     

PARALLEL FINITE ELEMENT ANALYSIS OF HIGH FREQUENCY VIBRATIONS OF QUARTZ CRYSTAL RESONATORS ON LINUX CLUSTER

Quartz crystal resonators are typical piezoelectric acoustic wave devices for frequency control applications with mechanical vibration frequency at the radio-frequency （RF） range. Precise analyses of the vibration and deformation are generally required in the resonator design and improvement process. The considerations include the presence of electrodes, mountings, bias fields such as temperature, initial stresses, and acceleration. Naturally, the finite element method is the only effective tool for such a coupled problem with multi-physics nature. The main challenge is the extremely large size of resulted linear equations. For this reason, we have been employing the Mindlin plate equations to reduce the computational difficulty. In addition, we have to utilize the parallel computing techniques on Linux clusters, which are widely available for academic and industrial applications nowadays, to improve the computing efficiency. The general principle of our research is to use open source software components and public domain technology to reduce cost for developers and users on a Linux cluster. We start with a mesh generator specifically for quartz crystal resonators of rectangular and circular types, and the Mindlin plate equations are implemented for the finite element analysis. Computing techniques like parallel processing, sparse matrix handling, and the latest eigenvalue extraction package are integrated into the program. It is clear from our computation that the combination of these algorithms and methods on a cluster can meet the memory requirement and reduce computing time significantly.     

Topography guiding the accelerated and persistently directional cell migration induced by vaccinia virus

The rapid transmission of vaccinia virus(VACV)in vivo is thought to be closely related to the cell migration induced by it.Cell migration involved in dynamic changes of cell-substrate adhesion and actin cytoskeleton organization,which can influence by the micro/nano-scale topographic structures that cells are naturally exposed to via contact guidance.However,migration behaviors of VACV-infected cells exposed to topographic cues are still unknown.Herein,we designed an open chip with microgrooved poly(dimethyl siloxane)(PDMS)substrate to explore the topography roles in VACV-induced cell migration.Differed from the random cell migration observed in traditional scratch assay on planar substrate,VACV-infected cells had a tendency to persistently migrate along the axis parallel to microgroove with increased velocity.Moreover,infected cells exhibited a dominant elongated protrusion aligned to the micro-grating axis compare to the shorter lamella extended in any direction on smooth substrate.Interestingly,the Golgi complex preferred to relocate behind the nucleus confined within the micro-grating axis in majority of infected migratory cells.The directional polarization of cells embodied in protrusion formation and Golgi reorientation was responsible for the directionally persistent migration behaviors induced by VACV on microgrooved substrate.Infected cells response to substrate topography,causing the actin-filled stretched protrusion containing numerous virions and accelerated movement is likely to facilitate direct and rapid spread of VACV.This work opens a window for us to understand the migration behaviors of infected cells in vivo,and also provides a cue for revealing the relationship between virus-induced cell migration and virus rapid spread.     

Coupled extension and thickness-twist vibrations of lateral field excited AT-cut quartz plates简

In this paper, the coupled extension and thickness- twist vibrations are studied for AT-cut quartz plates under Lateral Field Excitation （LFE） with variations along the x1- direction. Mindlin＇s two-dimensional equations are used for anisotropic crystal plates. Both free and electrically forced vibrations are considered. Important vibration characteristics are obtained, including dispersion relations, frequency spectra, and motional capacitances. It is shown that, to avoid the effects of the couplings between extension and thickness-twist vibrations, a series of discrete values of the length/thickness ratio of the crystal plate need to be excluded. The results are of fundamental significance for the design of LFE resonators and sensors.     

Highly sensitive Fe3O4 nanobeads/graphene-based molecularly imprinted electrochemical sensor for 17β-estradiol in water

A novel molecularly imprinted electrochemical sensor based on Fe₃O₄ nanobeads immobilized on graphene (Fe₃O₄-MIP@RGO) has been developed for detecting 17β-estradiol (17β-E2) in water using reversible addition fragmentation chain transfer (RAFT) polymerization technique. 17β-E2 can be detected by this electrochemical sensor through the response current change before and after binding 17β-E2. The Fe₃O₄-MIP@RGO-based sensor amplifies the response current in differential pulse voltammetry measurement, allowing the detection limit reaching 0.819 nM in a wide linear range from 0.05 to 10 μM. Moreover, Fe₃O₄-MIP@RGO-based sensor exhibits high selectivity and sensitivity towards 17β-E2. This MIP electrochemical sensor has a promising potential in the detection of 17β-E2 in water.     

PROPAGATION OF LOVE WAVES IN PRESTRESSED PIEZOELECTRIC LAYERED STRUCTURES LOADED WITH VISCOUS LIQUID

We investigate analytically the effect of initial stress in piezoelectric layered structures loaded with viscous liquid on the dispersive and attenuated characteristics of Love waves, which involves a thin piezoelectric layer bonded perfectly to an unbounded elastic substrate. The effects of initial stress in the piezoelectric layer and the viscous coefficient of the liquid on the phase velocity of Love waves are analyzed. Numerical results are presented and discussed. The analytical method and the results can be useful for the design of chemical and biosensing liquid sensors.