On the General Analytical Solution of the Kinematic Cosserat Equations

Based on a Lie symmetry analysis, we construct a closed form solution to the kinematic part of the (partial differential) Cosserat equations describing the mechanical behavior of elastic rods. The solution depends on two arbitrary analytical vector functions and is analytical everywhere except a certain domain of the independent variables in which one of the arbitrary vector functions satisfies a simple explicitly given algebraic relation. As our main theoretical result, in addition to the construction of the solution, we proof its generality. Based on this observation, a hybrid semi-analytical solver for highly viscous two-way coupled fluid-rod problems is developed which allows for the interactive high-fidelity simulations of flagellated microswimmers as a result of a substantial reduction of the numerical stiffness.Comment: 14 pages, 3 figure

Random field sampling for a simplified model of melt-blowing considering turbulent velocity fluctuations

In melt-blowing very thin liquid fiber jets are spun due to high-velocity air streams. In literature there is a clear, unsolved discrepancy between the measured and computed jet attenuation. In this paper we will verify numerically that the turbulent velocity fluctuations causing a random aerodynamic drag on the fiber jets -- that has been neglected so far -- are the crucial effect to close this gap. For this purpose, we model the velocity fluctuations as vector Gaussian random fields on top of a k-epsilon turbulence description and develop an efficient sampling procedure. Taking advantage of the special covariance structure the effort of the sampling is linear in the discretization and makes the realization possible

Arsenic Trioxide Enhances the Radiation Sensitivity of Androgen-Dependent and -Independent Human Prostate Cancer Cells

Prostate cancer is the most common malignancy in men. In the present study, LNCaP (androgen-sensitive human prostate cancer cells) and PC-3 cells (androgen-independent human prostate cancer cells) were used to investigate the anti-cancer effects of ionizing radiation (IR) combined with arsenic trioxide (ATO) and to determine the underlying mechanisms in vitro and in vivo. We found that IR combined with ATO increases the therapeutic efficacy compared to individual treatments in LNCaP and PC-3 human prostate cancer cells. In addition, combined treatment showed enhanced reactive oxygen species (ROS) generation compared to treatment with ATO or IR alone in PC-3 cells. Combined treatment induced autophagy and apoptosis in LNCaP cells, and mainly induced autophagy in PC-3 cells. The cell death that was induced by the combined treatment was primarily the result of inhibition of the Akt/mTOR signaling pathways. Furthermore, we found that the combined treatment of cells pre-treated with 3-MA resulted in a significant change in AO-positive cells and cytotoxicity. In an in vivo study, the combination treatment had anti-tumor growth effects. These novel findings suggest that combined treatment is a potential therapeutic strategy not only for androgen-dependent prostate cancer but also for androgen-independent prostate cancer

Tunable and reconfigurable multi-tap microwave photonic filter based on dynamic Brillouin gratings in fibers

This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.006157. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawWe propose and experimentally demonstrate new architectures to realize multi-tap microwave photonic filters, based on the generation of a single or multiple dynamic Brillouin gratings in polarization maintaining fibers. The spectral range and selectivity of the proposed periodic filters is extensively tunable, simply by reconfiguring the positions and the number of dynamic gratings along the fiber respectively. In this paper, we present a complete analysis of three different configurations comprising a microwave photonic filter implementation: a simple notch-type Mach-Zehnder approach with a single movable dynamic grating, a multi-tap performance based on multiple dynamic gratings and finally a stationary grating configuration based on the phase modulation of two counter-propagating optical waves by a common pseudo-random bit sequence (PRBS).The authors wish to acknowledge the financial support of the European Community's Seventh Framework Programme (FP 7) project GOSPEL; the GVA PROMETEO 2008/092, Infraestructura FEDER UPVOV08-3E-008, the Plan Nacional I + D TEC2011-29120-C05-05, the Swiss National Science Foundation through project 200021-134546 and the EPFL Space Center, the Israeli Science Foundation (ISF), and the KAMIN program of the Chief Scientist Office, Israel Ministry of Industry, Trade and Labor.Sancho Durá, J.; Sales Maicas, S.; Primerov, N.; Chin, S.; Antman, Y.; Zadok, A.; Thevenaz, L. (2012). Tunable and reconfigurable multi-tap microwave photonic filter based on dynamic Brillouin gratings in fibers. Optics Express. 20(6):6157-6162. https://doi.org/10.1364/OE.20.006157S61576162206Seeds, A. J. (2002). Microwave photonics. IEEE Transactions on Microwave Theory and Techniques, 50(3), 877-887. doi:10.1109/22.989971Capmany, J., & Novak, D. (2007). Microwave photonics combines two worlds. Nature Photonics, 1(6), 319-330. doi:10.1038/nphoton.2007.89Capmany, J., Ortega, B., Pastor, D., & Sales, S. (2005). Discrete-time optical Processing of microwave signals. Journal of Lightwave Technology, 23(2), 702-723. doi:10.1109/jlt.2004.838819Yao, J. (2009). Microwave Photonics. Journal of Lightwave Technology, 27(3), 314-335. doi:10.1109/jlt.2008.2009551Minasian, R. A. (2006). Photonic signal processing of microwave signals. IEEE Transactions on Microwave Theory and Techniques, 54(2), 832-846. doi:10.1109/tmtt.2005.863060Mørk, J., Kjær, R., van der Poel, M., & Yvind, K. (2005). Slow light in a semiconductor waveguide at gigahertz frequencies. Optics Express, 13(20), 8136. doi:10.1364/opex.13.008136Su, H., Kondratko, P., & Chuang, S. L. (2006). Variable optical delay using population oscillation and four-wave-mixing in semiconductor optical amplifiers. Optics Express, 14(11), 4800. doi:10.1364/oe.14.004800Song, K. Y., Herr�ez, M. G., & Th�venaz, L. (2005). Observation of pulse delaying and advancement in optical fibers using stimulated Brillouin scattering. Optics Express, 13(1), 82. doi:10.1364/opex.13.000082Song, K. Y., Zou, W., He, Z., & Hotate, K. (2008). All-optical dynamic grating generation based on Brillouin scattering in polarization-maintaining fiber. Optics Letters, 33(9), 926. doi:10.1364/ol.33.000926Song, K. Y., & Yoon, H. J. (2010). Observation of narrowband intrinsic spectra of Brillouin dynamic gratings. Optics Letters, 35(17), 2958. doi:10.1364/ol.35.002958Kwang Yong Song, Sanghoon Chin, Primerov, N., & Thevenaz, L. (2010). Time-Domain Distributed Fiber Sensor With 1 cm Spatial Resolution Based on Brillouin Dynamic Grating. Journal of Lightwave Technology, 28(14), 2062-2067. doi:10.1109/jlt.2010.205076

Factors that Impact Susceptibility to Fiber-Induced Health Effects

Asbestos and related fibers are associated with a number of adverse health effects, including malignant mesothelioma (MM), an aggressive cancer that generally develops in the surface serosal cells of the pleural, pericardial, and peritoneal cavities. Although approximately 80% of individuals with MM are exposed to asbestos, fewer than 5% of asbestos workers develop MM. In addition to asbestos, other mineralogical, environmental, genetic, and possibly viral factors might contribute to MM susceptibility. Given this complex etiology of MM, understanding susceptibility to MM needs to be a priority for investigators in order to reduce exposure of those most at risk to known environmental carcinogens. In this review, the current body of literature related to fiber-associated disease susceptibility including age, sex, nutrition, genetics, asbestos, and other mineral exposure is addressed with a focus on MM, and critical areas for further study are recommended