Polarized light microscopy in reproductive and developmental biology

Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Molecular Reproduction and Development (2013), doi:10.1002/mrd.22221.The polarized light microscope reveals orientational order in native molecular structures inside living cells, tissues, and whole organisms. Therefore, it is a powerful tool to monitor and analyze the early developmental stages of organisms that lend themselves to microscopic observations. In this article we briefly discuss the components specific to a traditional polarizing microscope and some historically important observations on chromosome packing in sperm head, first zygote division of the sea urchin, and differentiation initiated by the first uneven cell division in the sand dollar. We then introduce the LC-PolScope and describe its use for measuring birefringence and polarized fluorescence in living cells and tissues. Applications range from the enucleation of mouse oocytes to analyzing the polarized fluorescence of the water strider acrosome. We end by reporting first results on the birefringence of the developing chick brain, which we analyzed between developmental stages of days 12 through 20.This work was supported by funds from the National Institute of General Medical Sciences (grant 1R01GM100160-01A1 awarded to TT) and the National Institute of Biomedical Imaging and Bioengineering (grant EB002045 awarded to RO)

Design And Demonstration Of Meanderline Retarders At Infrared Frequencies

Meanderline structures are widely used as engineered birefringent materials for waveplates and retarders at radiofrequencies, and have been previously demonstrated at frequencies up to 90 GHz in the millimeter-wave band. In this dissertation, we present results related to the modeling, fabrication, and experimental characterization of meanderlines across the range from 30 to 100 THz, in the long-wave and mid-wave infrared bands. Specific issues addressed in these new designs include spectral dispersion and angular dependence of the retardance, as well as axial ratio and throughput. The impact resulting from the infrared properties of the metals and dielectrics is explicitly included throughout. Several novel applications are identified, including integrated circular polarizers, reflective waveplates, and large-area polarization tags

An Ultrafast Source of Polarization Entangled Photon Pairs based on a Sagnac Interferometer

This thesis describes the design, development, and implementation of a pulsed source of polarization-entangled photons using spontaneous parametric down-conversion in a Sagnac interferometer. A tangle of 0.9286 ± 0.0015, fidelity to the state (|10〉 + |01〉)/√2 of 0.9798 ± 0.0004 and a brightness of 597 pairs/s/mW were demonstrated. Spontaneous parametric down-conversion is a nonlinear optical process in which one photon is split into two lower-frequency photons while conserving momentum and energy, in this experiment nearly degenerate photons are produced. These photons are then interfered at the output beamsplitter of the interferometer, exchanging path entanglement for polarization entanglement and generating the desired polarization-entangled photon pairs

Political Contributions and Firm Performance: Evidence from Lobbying and Campaign Donations

The following dissertation contains two distinct empirical essays which contribute to the overall field of Financial Economics. Chapter 1 titles as “Corporate Lobbying, CEO Political Ideology and Firm Performance”. We investigate the influence of CEO political orientation on corporate lobbying efforts. Specifically, we study whether CEO political ideology, in terms of manager-level campaign donations, determines the choice and amount of firm lobbying involvement and the impact of lobbying on firm value. We find a generous engagement in lobbying efforts by firms with Republican leaning-managers, which lobby a larger number of bills and have higher lobbying expenditures. However, the cost of lobbying offsets the benefit for firms with Republican CEOs. We report higher agency costs of free cash flow, lower Tobin’s Q, and smaller increases in buy and hold abnormal returns following lobbying activities for firms with Republican managers, compared to Democratic and Apolitical rivals. Overall, our results suggest that the effects of lobbying on firm performance vary across firms with different managerial political orientations. Chapter 2 titled as “Corporate Lobbying and Labor Relations: Evidence from Employee” Litigations. We utilize employee litigations and other work-related complaints to examine if lobbying firms are favored in judicial process. We gather 27,794 employee lawsuits (after initial court hearing) between 2000 and 2014 and test the relationship between employee allegations and firms’ lobbying strategies. We find that employee litigations increase the number of labor-related bills in our sample. We document that the increase in employee lawsuits may drive firms into lobbying to change policy proposals. We also find robust evidence that the case outcome is different for lobbying firms compared to non-lobbying rivals, which may protect the shareholder wealth in the long run. Our results present that lobbying activities may make a significant difference in employee allegations. Our findings highlight the benefit of building political capital to obtain a biased outcome in favor of politically-connected firms

Political Contributions and Firm Performance: Evidence from Lobbying and Campaign Donations

The following dissertation contains two distinct empirical essays which contribute to the overall field of Financial Economics. Chapter 1 titles as “Corporate Lobbying, CEO Political Ideology and Firm Performance”. We investigate the influence of CEO political orientation on corporate lobbying efforts. Specifically, we study whether CEO political ideology, in terms of manager-level campaign donations, determines the choice and amount of firm lobbying involvement and the impact of lobbying on firm value. We find a generous engagement in lobbying efforts by firms with Republican leaning-managers, which lobby a larger number of bills and have higher lobbying expenditures. However, the cost of lobbying offsets the benefit for firms with Republican CEOs. We report higher agency costs of free cash flow, lower Tobin’s Q, and smaller increases in buy and hold abnormal returns following lobbying activities for firms with Republican managers, compared to Democratic and Apolitical rivals. Overall, our results suggest that the effects of lobbying on firm performance vary across firms with different managerial political orientations. Chapter 2 titled as “Corporate Lobbying and Labor Relations: Evidence from Employee” Litigations. We utilize employee litigations and other work-related complaints to examine if lobbying firms are favored in judicial process. We gather 27,794 employee lawsuits (after initial court hearing) between 2000 and 2014 and test the relationship between employee allegations and firms’ lobbying strategies. We find that employee litigations increase the number of labor-related bills in our sample. We document that the increase in employee lawsuits may drive firms into lobbying to change policy proposals. We also find robust evidence that the case outcome is different for lobbying firms compared to non-lobbying rivals, which may protect the shareholder wealth in the long run. Our results present that lobbying activities may make a significant difference in employee allegations. Our findings highlight the benefit of building political capital to obtain a biased outcome in favor of politically-connected firms

Advances in Cholesteric Liquid Crystals

With their helical structure, cholesteric liquid crystals figure prominently in liquid crystal science. The selective reflection of light is their flagship property, and they offer a myriad of applications as advanced optical materials with multiscale properties. The cholesteric structure is also a ubiquitous design in the animal and plant kingdoms. This book contains eight contributions on fundamental investigations about defects, textures and structures of cholesteric materials, and experimental studies aimed at applications such as temperature sensors, head-up displays for improving automobile driving safety, or smart windows

Manipulation of Photonic Orbital Angular Momentum for Quantum Information Processing

Computer modelling & simulatio