Bulletin of the American Physical Society
Spring 2013 Meeting of the APS Ohio-Region Section
Volume 58, Number 2
Friday–Saturday, March 29–30, 2013; Athens, Ohio
Session D2: Bio/Educational/Optics |
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Chair: Richard Piccard, Ohio University Room: Gover Hall E206 |
Saturday, March 30, 2013 9:00AM - 9:12AM |
D2.00001: Mechanical properties of cancer cells: A possible biomarker for stemness Ameneh Mohammadalipour, Fabian Benencia, Monica Burdick, David Tees There is evidence that mechanical properties and deformability can be used as a biomarker to distinguish between healthy and cancerous cells. In this study, micropipette aspiration was used to investigate deformability differences between two breast cancer cell lines: BT-20 and Hs578T. Hs578T breast cancer cells have been reported to have a stem-like phenotype, whereas BT-20 cells are more recognized as being non-stem-like. Cancer cells were aspirated one-by-one at controlled pressures into small glass micropipettes with radius $R_{p}$ while the length of the aspirated section of the cell inside the micropipette $L$ was measured. We found that stem-like cancer cells are softer than non-stem-like cells with no significant differences between the mechanical properties of their cytoplasmic and nuclear regions, which allows them to deform more easily while undergoing extravasation and intravasation processes during metastasis. Our hypothesis is that the stem-like or non-stem-like phenotype of cancer cells is correlated with differences in mechanical properties. If these differences are significant enough, mechanical properties could be used as a biomarker for stemness of cells, which could eventually lead to a new diagnostic method in cancer research. [Preview Abstract] |
Saturday, March 30, 2013 9:12AM - 9:24AM |
D2.00002: Areal variations in world temperature Increase Gordon Aubrecht Earth's temperature is rising. Is the rise distributed uniformly around the world? We compare the world record to the US and Australian records, and those to Ohio records to see what the data show. [Preview Abstract] |
Saturday, March 30, 2013 9:24AM - 9:36AM |
D2.00003: Introductory Physics Courses and The Change to Semesters James Sullivan Beginning in the autumn of 2012 the University of Cincinnati, as well as many other institutions in Ohio changed from a quarter (term) calendar to a semester calendar. At this time the state also initiated a TAG program that attempts to insure uniform courses throughout the state system of higher education. A report on how these changes in the two basic introductory Physics Courses (Calculus-based and algebra/Trigonometry based) at the University of Cincinnati will be given here. [Preview Abstract] |
Saturday, March 30, 2013 9:36AM - 9:48AM |
D2.00004: Expanding a school intervention program Gordon Aubrecht With support from the Math and Science Partnership through the Ohio Department of Education, we have discovered a tripartite method that worked at increasing scores on high-stakes tests in an at-risk school system. The three parts are a summer content program, grade-level lesson development by teachers working together, and the use of common grade-level formative assessment analysis by teachers. We are going to see whether what worked in the one school system also works in a different school system. Details will be discussed. [Preview Abstract] |
Saturday, March 30, 2013 9:48AM - 10:00AM |
D2.00005: The Hybrid Phonoriton in Organic-Semiconductor Heterostructures David Facemyer In this work electronic structures and optical properties of organic-inorganic phonoriton, a new elementary excitation existing in heterostructures combining both organic and semiconductor materials, are studied. In those systems, the Wannier-Frenkel hybrid exciton has unique and interesting properties that can improve the efficiency of optical materials. When an organic-semiconductor combined heterostructure is illuminated by high-intensity electromagnetic radiation with the frequency of the photons at or near the resonance frequency of the Wannier-Frenkel exciton, we obtain a macroscopically occupied system of hybrid polaritons that further interacts with phonons which will in turn generate the hybrid phonoriton. We will theoretically determine electronic structure, energy and dispersion relation of phonoritons. By analyzing the interactions between the hybrid exciton, photons and phonons, it may be possible to discuss the conditions for phonoriton formation. [Preview Abstract] |
Saturday, March 30, 2013 10:00AM - 10:12AM |
D2.00006: Determining microstructural features of a composite from effective properties Anthony Day, Andrew McElroy, Gregory Sowa The effective dielectric function of a composite depends on the microstructure of the composite as well as the dielectric function of the constituent materials. In the Bergman-Milton spectral representation, all of the information about the microstructure that is needed to determine the effective properties is contained in a spectral function which is independent of the material properties. We demonstrate a method for extracting the spectral function of the composite from measured reflectivity data using a continued fraction representation effective dielectric function. By using simulated data from a model system with a known spectral function we show that the method accurately reproduces the known spectral function. The method is fast, robust and only requires a fairly small number of fitting parameters which can be related to features of the microstructure. [Preview Abstract] |
Saturday, March 30, 2013 10:12AM - 10:24AM |
D2.00007: Semiconductor-core optical fibers for terahertz waveguides Derek Bas Waveguiding of terahertz (THz) radiation is important for imaging and communications applications. Simulations have been performed based on a fiber optic geometric waveguide with a poly-crystalline silicon core and silica cladding [1]. High-resistivity silicon has a flat dispersion over a 0.1 -- 3 THz range [2], making it viable for propagation of broadband picosecond pulses of THz radiation such as that produced by optical rectification [3]. Frequency-dependent mode indices are determined for 0.1 -- 0.3 mm diameter cores. The normalized frequency parameter V is also determined and a 140 micron core is selected as the low edge of diameters that can support a THz pulse. Finite-difference time-domain simulations are performed in two-dimensions to extract the propagation dynamics and the integrated intensity, from which transverse mode profiles and absorption lengths are extracted. It is found that for this core diameter the mode partially propagates in the cladding, such that the overall absorbance is only slightly less than in bulk polycrystalline silicon.\\[4pt] [1] J. Ballato, T. Hawkins, P. Foy, R. Stolen, B. Kokuoz, M. Ellison, C. McMillen, J. Reppert, A. M. Rao, M. Daw, S. R. Sharma, R. Shori, O. Stafsudd, R. R. Rice, and D. R. Powers, Opt. Express 16, 18675-18683 (2008) \\[0pt] [2] D. Grischkowsky, S{\o}ren Keiding, Martin van Exter, Ch. Fattinger, J. Opt. Soc. Am. B 7, 2006 (1990) \\[0pt] [3] J. D. Rowley, J. K. Pierce, A. T. Brant, L. E. Halliburton, N. C. Giles, P. G. Schunemann, A. D. Bristow, Opt. Lett. 37, 788 (2012) [Preview Abstract] |
Saturday, March 30, 2013 10:24AM - 10:36AM |
D2.00008: Two Color micro-photoluminescence excitation studies of exciton states in Coupled Quantum Dots Ramana Thota, Eric Stinaff, Allan Bracker, Dan Gammon In this report we examined the charge states of various excitons found in the optical spectra of coupled In$_{\mathrm{1-x}}$Ga$_{\mathrm{x}}$As quantum dots (QDs) grown by molecular beam epitaxy, under two color optical excitation. This experiment is performed by using micro-photoluminescence excitation technique, where we keep the excitation energy of one laser fixed at the energy of wetting layer (non-resonant excitation) and tuning the excitation energy of the other laser through the states of quantum dot (resonant excitation). This study may help identifying enhanced states of various charge excitons, which are possibly useful for generating on demand entangle photon pairs with QDs. [Preview Abstract] |
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