Bistable reflectivity in bulky semiconductors due to two photon-biexciton transitions

A new mechanism has been proposed for optical bistability in a bulk system of interacting photons and biexcitons. Bistable behaviour can occur for very low pumping intensities if the input light frequency is clearly less than the two-photon resonance of the biexciton.     

Application of stochastic analytic hierarchy process within a domestic appliance manufacturer

The stochastic analytic hierarchy process (SAHP) provides a mechanism for achieving more effective selection of alternatives in the form of considering multi and conflicting criteria using quantitative and qualitative information under uncertainty. In contrast to the traditional analytic hierarchy process, the SAHP uses probabilistic distributions to incorporate uncertainty that people have in converging their judgements of preferences into a Likert scale. The vector of priorities is calculated using Monte Carlo simulation, the final rankings are analysed for rank reversal using statistical analysis, and managerial aspects are introduced systematically. The present paper demonstrates an application of the SAHP in a world-class domestic appliance manufacturer. The case study was carried out by strictly following a disciplined and organized methodology for applying the SAHP developed by the authors. The results of this study were encouraging to key personnel within the company, establishing a greater opportunity to explore the applications of the SAHP in other core business processes.     

Simulating listener errors in using genetic algorithms for perceptual optimization

The genetic algorithm (GA) was previously suggested for fitting hearing aid or cochlear implant features by using listener's subjective judgment. In the present study, two human factors that might affect the outcome of the GA when used for perceptual optimization were explored with simulations. Listeners with varying sensitivity in discriminating sentences of different intelligibility and with varying error rates in entering their judgment to the GA were simulated. A comparison of the simulation results with the results from human subjects reported by Ba?kent et al. Ear Hear. 28(3) 277-289 (2007) showed that these factors could reduce the performance of the GA considerably.     

Influence of the central metal atom on the nonlinear optical properties of MPcs solutions and thin films

Third order nonlinear optical susceptibility (χ^〈3〉) of metallophthalocyanines (MPcs, where M = Co, Cu, Zn, Mg) thin films and solutions was investigated by standard backward degenerate four wave mixing (DFWM) method at 532 nm. Third harmonic generation (THG) measurement at 1064 nm performed on MPcs thin films is also discussed. MPcs thin films were grown by conventional thermal evaporation in high vacuum and solution were dissolved in tetrahydrofuran (THF), in which the studied materials are soluble. In the case of microscopic nonlinearity, we calculated the second order hyperpolarizability (γ) for MPcs solutions. We found that the χ^〈3〉 and the γ values are affected by the nature of the central metal atom. We also found that the value is larger than that measured via THG experiment. The variation in χ^〈3〉 values occurs due to the different resonance contributions.     

Fluorescent Coumarin–Artemisinin Conjugates as Mitochondria‐Targeting Theranostic Probes for Enhanced Anticancer Activities

Mitochondria‐targeting theranostic probes that enable the simultaneously reporting of and triggering of mitochondrial dysfunctions in cancer cells are highly attractive for cancer diagnosis and therapy. Three fluorescent mitochondria‐targeting theranostic probes have been developed by linking a mitochondrial dye, coumarin‐3‐carboximide, with a widely used traditional Chinese medicine, artemisinin, to kill cancer cells. Fluorescence images showed that the designed coumarin–artemisinin conjugates localized mainly in mitochondria, leading to enhanced anticancer activities over artemisinin. High cytotoxicity against cancer cells correlated with the strong ability to accumulate in mitochondria, which could efficiently increase the intracellular reactive oxygen species level and induce cell apoptosis. This study highlights the potential of using mitochondria‐targeting fluorophores to selectively trigger and directly visualize subcellular drug delivery in living cells.     

Sharp oscillation and nonoscillation tests for linear difference equations

We consider difference equations with a single delay term and obtain sufficient conditions for both oscillation and nonoscillation. Moreover, our nonoscillation theorem improves the affirmative answer to Ladas’ corrected conjecture given by Tang and Yu in [Comput. Math. Appl. 38(11–12) (1999), pp. 229–237]. We also present a detailed discussion with examples to emphasize the significance and the sharpness of the new results.