Antiproliferation- and Apoptosis-Inducible Effects of a Novel Nitrated [6,6,6]Tricycle Derivative (SK2) on Oral Cancer Cells

The benzo-fused dioxabicyclo[3.3.1]nonane core is the central framework in several natural products. Using this core, we had developed a novel nitrated [6,6,6]tricycle-derived compound containing an n-butyloxy group, namely, SK2. The anticancer potential of SK2 was not assessed. This study aimed to determine the antiproliferative function and investigated possible mechanisms of SK2 acting on oral cancer cells. SK2 preferentially killed oral cancer cells but caused no harmful effect on non-malignant oral cells. After the SK2 exposure of oral cancer cells, cells in the sub-G1 phase accumulated. This apoptosis-like outcome of SK2 treatment was validated to be apoptosis via observing an increasing annexin V population. Mechanistically, apoptosis signalers such as pancaspase, caspases 8, caspase 9, and caspase 3 were activated by SK2 in oral cancer cells. SK2 induced oxidative-stress-associated changes. Furthermore, SK2 caused DNA damage (γH2AX and 8-hydroxy-2′-deoxyguanosine). In conclusion, a novel nitrated [6,6,6]tricycle-derived compound, SK2, exhibits a preferential antiproliferative effect on oral cancer cells, accompanied by apoptosis, oxidative stress, and DNA damage.     

Software lens compensation applied to athermalization of infrared imaging systems

A different approach, aiming to achieve the constant blur status of point-spread function (PSF) at a certain defocused plane, is described. The correlation between the two PSF is used to control the PSF blur similarity, and simultaneously the Strehl ratio is also used to control the PSF blur minimization. By designing the PSF so that it is significantly insensitive to defocus or related defocus quantity, for example, due to temperature change, all the constantly blurred images can be accurately de-blurred by a simple inverse restoration filter for an adequate range of defocus. We refer to that as “software lens compensation” and apply a design method to solve the athermalization of middle wavelength infrared (MWIR) imaging systems. The resultant PSF is almost invariant in the temperature range from −10 to 50°C at the same focal plane. Consequently, the constant blur spot can be removed by a simple digital signal processing. Thus, clear and sharp de-blurred images at different temperatures are obtained.     

Solving polynomials by radicals with roots of unity in minimum depth

Let be an algebraic number field. Let be a root of a polynomial which is solvable by radicals. Let be the splitting field of over . Let be a natural number divisible by the discriminant of the maximal abelian subextension of , as well as the exponent of , the Galois group of over . We show that an optimal nested radical with roots of unity for can be effectively constructed from the derived series of the solvable Galois group of over .

     

Tunable diffraction of magnetic fluid films and its potential application in coarse wavelength-division multiplexing

When an external magnetic field is applied parallel to the film surface of a magnetic fluid film, a high-quality one-dimensional periodic chain structure is formed when the field strength reaches a certain level. With a periodic chain structure in the magnetic fluid film, an incident light is diffracted onto the magnetic thin film. The results show that the one-dimensional periodic chain structure in the magnetic fluid film can serve as an optical grating. Further investigations reveal the feasibility of developing tunable coarse wavelength-division multiplexing by utilizing a periodic chain structure.     

Dynamic stability of rotor-bearing systems subjected to random axial forces

This paper investigates the lateral vibration of a spinning disk-shaft system supported by a pair of ball bearings and subjected to a pair of random axial forces at both ends. The axial forces are assumed as the sum of a static force and a random process with a zero mean. Due to the random axial forces, the rotor-bearing system may experience parametric random instability under certain situations. In this work, the finite element method is applied to yield a set of discretized system equations first. The set of discretized system equations is partially uncoupled by the modal analysis procedure suitable for gyroscopic systems. The stochastic averaging method is then adopted to obtain Ito's equations for the response amplitudes of the system. Finally the first- and second-moment stability criteria are utilized to determine the stability boundaries of the system. Numerical results show that the rotor-bearing system is always stable in the sense of the first-moment stability, and the effects of the average axial compressive force and the disk mass, which will lower all frequencies of the system, tend to destabilize the second-moment stability of the system.     

Bulk universality for Wigner matrices

We consider N × N Hermitian Wigner random matrices H where the probability density for each matrix element is given by the density ν(x) = e^?U(x). We prove that the eigenvalue statistics in the bulk are given by the Dyson sine kernel provided that U ∈ C⁶( \input amssym $\Bbb R$ ) with at most polynomially growing derivatives and ν(x) ≥ Ce^?C|x| for x large. The proof is based upon an approximate time reversal of the Dyson Brownian motion combined with the convergence of the eigenvalue density to the Wigner semicircle law on short scales. © 2010 Wiley Periodicals, Inc.     

Generation of hyperchaos from the Chen–Lee system via sinusoidal perturbation

A system with more than one positive Lyapunov exponent can be classified as a hyperchaotic system. In this study, a sinusoidal perturbation was designed for generating hyperchaos from the Chen–Lee chaotic system. The hyperchaos was identified by the existence of two positive Lyapunov exponents and bifurcation diagrams. The system is hyperchaotic in several different regions of the parameters c, ε, and ω. It was found that this method not only can enhance or suppress chaotic behavior, but also induces chaos in non-chaotic parameter ranges. In addition, two interesting dynamical behaviors, Hopf bifurcation and intermittency, were also found in this study.     

Synergistic antitumor effect of curcumin and dinitrosyl iron complexes for against melanoma cells

The aim of this study was to examine whether combining curcumin, a chemoprevention agent, and dinitrosyl iron complexes (DNICs) would have a synergistic cytotoxic effect on mouse melanoma B16-F10 cells in vitro. Three synthesized DNICs-[PPN] [(NO)₂Fe(SCH₂CONHCH₃)₂] (NC01), [PPN] [(NO)₂Fe(SCH₂CON(CH₃)₂)₂] (NC02), and [Na][(NO)₂Fe(SCH₂CON(CH₃)₂)₂] (NC03) were tested in this study. In vitro DNA cleavage assay showed all three DNICs could cause plasmid DNA damage through releasing NO under UV irradiation. The cytotoxicity assay demonstrated these DNICs were toxic to B16-F10 cells in vitro, and the estimated values of LD₅₀ (24 h of incubation) of NC01 and NC02 were 1 μM, while the values of LD₅₀ of NC03 was 200 μM. No synergistic cytotoxicity effect was noted in the treatments of the combinations of curcumin and DNICs. On the contrary, in the presence of NC03, the toxicity of curcumin was reduced. Using UV-Visible spectroscopy and fluorescence microscopy, we found NC03 might interact with curcumin and reduce the accumulation of curcumin in cells. Further experiments using the pretreatment of curcumin for 4 h followed by the treatment of NC03 showed the synergistic cytotoxic effect, while, the pretreatment of NC03 followed by the treatment of curcumin did not have any effect. This study provides the basis for further investigation on the effects of combinations of curcumin and other NO donors.     

Nonlinear electro-optic characteristic in a photoexcited semiconductor

We study the transport properties of a GaAs-based Gunn device under local optical excitation via direct numerical simulation. The simulation results show that the hysteretic transition in between quenched and transit modes. The key mechanism for this kind of transition is related to the formation of a stationary and nonuniform hole profile around the notch regime. Therefore, the development of optical control of the microwave output is reported. In addition, the influence of impact ionization on this nonlinear semiconductor is also discussed in the present study.