National Technical University of Athens

About: National Technical University of Athens is a education organization based out in Athens, Attiki, Greece. It is known for research contribution in the topics: Large Hadron Collider & Nonlinear system. The organization has 13445 authors who have published 31259 publications receiving 723504 citations. The organization is also known as: Athens Polytechnic & NTUA.

Coumarin-based drugs: a patent review (2008 -- present).

Abstract: Introduction: Coumarins are a group of plant-derived polyphenolic compounds. They belong to the benzopyrones family and possess a wide variety of cytoprotective and modulatory functions, which may be translated to therapeutic potentials for multiple diseases. Their physicochemical properties seem to define the extent of the biological activity. Areas covered: In this review recent patent publications (2008 – 2011), describing coumarins and their derivatives, are analyzed. Synthesis, combinatorial techniques, biological evaluation in vitro/in vivo/ex vivo, e.g. antimitotic, immunomodulating, antiviral, anticancer and cytotoxic agents, as well as some new biological assays, are included. In addition to selected biological data, a wide range of pharmaceutical applications and pharmaceutical compositions are also summarized. Expert opinion: Several natural and synthetic coumarins and derivatives with potent in vivo/in vitro biological responses appear to be promising anticancer activities. Their clinical eval...

Suppressing Aeroelastic Instability Using Broadband Passive Targeted Energy Transfers, Part 2: Experiments

Abstract: This paper presents experimental results corroborating the analysis developed in the companion paper, Part 1 (Lee, Y., Vakakis, A., Bergman, L., McFarland, M., and Kerschen G., "Suppression Aeroelastic Instability Using Broadband Passive Targeted Energy Transfers, Part 1: Theory," AIAA Journal, Vol. 45, No. 3,2007, pp. 693-711), and demonstrates that a nonlinear energy sink can improve the stability of an aeroelastic system. The nonlinear energy sink was, in this case, attached to the heave (plunge) degree of freedom of a rigid airfoil which was supported in a low-speed wind tunnel by nonlinear springs separately adjustable in heave and pitch. This airfoil was found to exhibit a limit cycle oscillation at flow speeds above the critical ("flutter") speed of 9.5 m/s, easily triggered by an initial heave displacement. After attachment of a single degree of freedom, essentially nonlinear energy sink to the wing, the combined system exhibited improved dynamic response as measured by the reduction or elimination of limit cycle oscillation at flow speeds significantly greater than the wing's critical speed. The design, application, and performance of the nonlinear energy sink are described herein, and the results obtained are compared to analytical predictions. The physics of the interaction of the sink with the wing is examined in detail.

Search for Solar Axions by the CERN Axion Solar Telescope with 3He Buffer Gas: Closing the Hot Dark Matter Gap

Abstract: The CERN Axion Solar Telescope has finished its search for solar axions with He-3 buffer gas, covering the search range 0.64 eV less than or similar to ma less than or similar to 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(a gamma) less than or similar to 3.3 x 10(-10) GeV-1 at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g(a gamma), for example by the currently discussed next generation helioscope International AXion Observatory.