63 research outputs found

    Tailorable stimulated Brillouin scattering in nanoscale silicon waveguides

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    Nanoscale modal confinement is known to radically enhance the effect of intrinsic Kerr and Raman nonlinearities within nanophotonic silicon waveguides. By contrast, stimulated Brillouin-scattering nonlinearities, which involve coherent coupling between guided photon and phonon modes, are stifled in conventional nanophotonics, preventing the realization of a host of Brillouin-based signal-processing technologies in silicon. Here we demonstrate stimulated Brillouin scattering in silicon waveguides, for the first time, through a new class of hybrid photonic–phononic waveguides. Tailorable travelling-wave forward-stimulated Brillouin scattering is realized—with over 1,000 times larger nonlinearity than reported in previous systems—yielding strong Brillouin coupling to phonons from 1 to 18 GHz. Experiments show that radiation pressures, produced by subwavelength modal confinement, yield enhancement of Brillouin nonlinearity beyond those of material nonlinearity alone. In addition, such enhanced and wideband coherent phonon emission paves the way towards the hybridization of silicon photonics, microelectromechanical systems and CMOS signal-processing technologies on chip.United States. National Nuclear Security Administration (Contract DE-AC04-94AL85000)United States. Air Force (Contract FA8721-05-C-000)United States. Defense Advanced Research Projects Agency (MesoDynamic Architectures Program)Sandia National Laboratories (Directed Research and Development Program

    High-Performance Silicon Photonic Single-Sideband Modulators for Cold Atom Interferometry

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    The most complicated and challenging system within a light-pulse atom interferometer (LPAI) is the laser system, which controls the frequencies and intensities of multiple laser beams over time to configure quantum gravity and inertial sensors. The main function of an LPAI laser system is to perform cold-atom generation and state-selective detection and to generate coherent two-photon process for the light-pulse sequence. Substantial miniaturization and ruggedization of the laser system can be achieved by bringing together most key functions of the laser and optical system onto a photonic integrated circuit (PIC). Here we demonstrate a high-performance silicon photonic carrier-suppressed single-sideband (CS-SSB) modulator PIC with dual-parallel Mach-Zehnder modulators (DP-MZMs) operating near 1560 nm, which can dynamically shift the frequency of the light for the desired function within the LPAI. Independent RF control of channels in SSB modulator enables the extensive study of imbalances in both the optical and RF phases and amplitudes to simultaneously reach 30 dB carrier suppression and unprecedented 47.8 dB sideband suppression with peak conversion efficiency of -6.846 dB (20.7 %). Using a silicon photonic SSB modulator with time-multiplexed frequency shifting in an LPAI laser system, we demonstrate cold-atom generation, state-selective detection, and the realization of atom interferometer fringes to estimate gravitational acceleration, g9.77±0.01m/s2g \approx 9.77 \pm 0.01 \,\rm{m/s^2}, in a Rubidium (87^{87}Rb) atom system.Comment: 18 pages, 9 figure

    Fibroblast Growth Factor Receptor 1 Drives the Metastatic Progression of Prostate Cancer

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    BACKGROUND: No curative therapy is currently available for metastatic prostate cancer (PCa). The diverse mechanisms of progression include fibroblast growth factor (FGF) axis activation. OBJECTIVE: To investigate the molecular and clinical implications of fibroblast growth factor receptor 1 (FGFR1) and its isoforms (α/β) in the pathogenesis of PCa bone metastases. DESIGN, SETTING, AND PARTICIPANTS: In silico, in vitro, and in vivo preclinical approaches were used. RNA-sequencing and immunohistochemical (IHC) studies in human samples were conducted. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: In mice, bone metastases (chi-square/Fisher's test) and survival (Mantel-Cox) were assessed. In human samples, FGFR1 and ladinin 1 (LAD1) analysis associated with PCa progression were evaluated (IHC studies, Fisher's test). RESULTS AND LIMITATIONS: FGFR1 isoform expression varied among PCa subtypes. Intracardiac injection of mice with FGFR1-expressing PC3 cells reduced mouse survival (α, p < 0.0001; β, p = 0.032) and increased the incidence of bone metastases (α, p < 0.0001; β, p = 0.02). Accordingly, IHC studies of human castration-resistant PCa (CRPC) bone metastases revealed significant enrichment of FGFR1 expression compared with treatment-naïve, nonmetastatic primary tumors (p = 0.0007). Expression of anchoring filament protein LAD1 increased in FGFR1-expressing PC3 cells and was enriched in human CRPC bone metastases (p = 0.005). CONCLUSIONS: FGFR1 expression induces bone metastases experimentally and is significantly enriched in human CRPC bone metastases, supporting its prometastatic effect in PCa. LAD1 expression, found in the prometastatic PCa cells expressing FGFR1, was also enriched in CRPC bone metastases. Our studies support and provide a roadmap for the development of FGFR blockade for advanced PCa. PATIENT SUMMARY: We studied the role of fibroblast growth factor receptor 1 (FGFR1) in prostate cancer (PCa) progression. We found that PCa cells with high FGFR1 expression increase metastases and that FGFR1 expression is increased in human PCa bone metastases, and identified genes that could participate in the metastases induced by FGFR1. These studies will help pinpoint PCa patients who use fibroblast growth factor to progress and will benefit by the inhibition of this pathway.Fil: Labanca, Estefania. University of Texas; Estados UnidosFil: Yang, Jun. University of Texas; Estados UnidosFil: Shepherd, Peter D. A.. University of Texas; Estados UnidosFil: Wan, Xinhai. University of Texas; Estados UnidosFil: Starbuck, Michael W.. University of Texas; Estados UnidosFil: Guerra, Leah D.. University of Texas; Estados UnidosFil: Anselmino, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Bizzotto, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Dong, Jiabin. University of Texas; Estados UnidosFil: Chinnaiyan, Arul M.. University Of Michigan Medical School; Estados UnidosFil: Ravoori, Murali K.. University of Texas; Estados UnidosFil: Kundra, Vikas. University of Texas; Estados UnidosFil: Broom, Bradley M.. University of Texas; Estados UnidosFil: Corn, Paul G.. University of Texas; Estados UnidosFil: Troncoso, Patricia. University of Texas; Estados UnidosFil: Gueron, Geraldine. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Logothethis, Christopher J.. University of Texas; Estados UnidosFil: Navone, Nora. University of Texas; Estados Unido

    The Formative European Influences That Shaped The Thinking of Peter Ferdinand Drucker And How They Manifest Themselves In His Later Ideas

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    The object ofthis thesis is to identifY Drucker's fonnative influences during the first period of his life between 1909 and 1937, when he set out on an intellectualjoumey, not, as many would anticipate, to discover management but to find a just and workable society to replace what he regarded as the contemporary dysfunctional European ones. It will be shown that his discovery of'management' was a by-product ofhis search, not its primary objective. During this period ofhis life he lived in his native Austria, then in Germany and eventually • England, all before he emigrated to America. The justification for the selection ofhis major fonnative influences is supported by documentary evidence, which records what they were as people, and what their ideas were. Also where there is interplay between the influences this is demonstrated, as is also what their ideas meant to Drucker. It will be established which ideas .. Drucker rejected, which he accepted in part, and which he embraced. From this analysis, how Drucker dealt with the influences intellectually will be identified, and how they became part of his core ideas will be shown by straightforward adoption, synthesis or as a reaction to the proposals ofhis influences, which resulted in ideas ofhis own creation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    How replication studies can improve doctoral student education

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    In addition to helping advance theory, replication studies offer rich and complementary learning experiences for doctoral students, enabling them to learn general research skills, through the process of striving to imitate good studies. In addition, students gain replication-specific methodological skills and learn about the important roles replications play for making management knowledge trustworthy. We outline best practices for enabling doctoral students and their supervisors to select studies to replicate, execute their replications, and increase the probability of successfully publishing their findings. We also discuss the crucial role of faculty mentors in supporting and guiding replication-based learning of doctoral students. Ultimately, educating doctoral students on how to execute high-quality replication studies helps to answer wider calls for more replication studies in the field of management, an important stepping stone along the journey toward open and responsible research.This article is published as Schwab, A., Aguinis, H., Bamberger, P., Hodgkinson, G. P., Shapiro, D. L., Starbuck, W. H., & Tsui, A. S. (2023). How replication studies can improve doctoral student education. Journal of Management Scientific Reports, 1(1), 18–41. https://doi.org/10.1177/27550311231156880. Posted with permission. © The Author(s) 2023<br
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