École Polytechnique

About: École Polytechnique is a education organization based out in Palaiseau, France. It is known for research contribution in the topics: Laser & Plasma. The organization has 18995 authors who have published 39265 publications receiving 1225163 citations. The organization is also known as: Ecole Polytechnique & Polytechnique.

Synthesis of Large‐Area Graphene Layers on Poly‐Nickel Substrate by Chemical Vapor Deposition: Wrinkle Formation

Abstract: [*] Dr. J.-Y. Choi, H.-J. Shin, S.-M. Yoon Display Device and Processing Laboratory Samsung Advanced Institute of Technology PO Box 111, Suwon 440-600 (Republic of Korea) E-mail: jaeyoung88.choi@samsung.com Prof. Y. H. Lee, S. J. Chae, F. Gunes, Dr. K. K. Kim, E. S. Kim, G. H. Han, S. M. Kim, H.-J. Shin BK21 Physics Division Sungkyunkwan Advanced Institute of Nanotechnology Center for Nanotubes and Nanostructured Composites Sungkyunkwan University Suwon 440-746 (Republic of Korea) E-mail: leeyoung@skku.edu M. H. Park, Prof. C. W. Yang Department of Advanced Materials Engineering Sungkyunkwan University Suwon 440-746 (Republic of Korea)

Regulation of circadian behaviour and metabolism by REV-ERB-α and REV-ERB-β

Abstract: The circadian clock acts at the genomic level to coordinate internal behavioural and physiological rhythms via the CLOCK-BMAL1 transcriptional heterodimer. Although the nuclear receptors REV-ERB-α and REV-ERB-β have been proposed to form an accessory feedback loop that contributes to clock function, their precise roles and importance remain unresolved. To establish their regulatory potential, we determined the genome-wide cis-acting targets (cistromes) of both REV-ERB isoforms in murine liver, which revealed shared recognition at over 50% of their total DNA binding sites and extensive overlap with the master circadian regulator BMAL1. Although REV-ERB-α has been shown to regulate Bmal1 expression directly, our cistromic analysis reveals a more profound connection between BMAL1 and the REV-ERB-α and REV-ERB-β genomic regulatory circuits than was previously suspected. Genes within the intersection of the BMAL1, REV-ERB-α and REV-ERB-β cistromes are highly enriched for both clock and metabolic functions. As predicted by the cistromic analysis, dual depletion of Rev-erb-α and Rev-erb-β function by creating double-knockout mice profoundly disrupted circadian expression of core circadian clock and lipid homeostatic gene networks. As a result, double-knockout mice show markedly altered circadian wheel-running behaviour and deregulated lipid metabolism. These data now unite REV-ERB-α and REV-ERB-β with PER, CRY and other components of the principal feedback loop that drives circadian expression and indicate a more integral mechanism for the coordination of circadian rhythm and metabolism.

Optical properties of functional hybrid organic-inorganic nanocomposites

Abstract: Functional hybrids are nanocomporie umterials lying at the interfoce of organic and inorganic realnts, whose high sersatility offers a wide range of possibilities to eloborate tailor-made materials in terms of chemical and physical properties. Because they present several advantogys for derigning materialy for opticol applications (versatile and relativrly facite chemistry, easy shaping and patierning, materials having good mechanical integrity and cacrdlent optical quality), numerous silica or/and silaxane tussed hytirid orgunic-inorganic materiois imve been developed in the past few years. The men striking examples of fonctional hybrids exhibiting emission properties (solid-state dye lasers rare-carth doped hybridslads, electronuminescent devices), absorption properties (photockiomic), nonlinear optical (NLO) porperties (second-order NLO properties, phoiochemical hole burning (PHB), photorefractivity), and sensing are sunimorized in this review.

Giant tunnel electroresistance for non-destructive readout of ferroelectric states

Abstract: Ferroelectrics possess a polarization that is spontaneous, stable and electrically switchable, and submicrometre-thick ferroelectric films are currently used as non-volatile memory elements with destructive capacitive readout. Memories based on tunnel junctions with ultrathin ferroelectric barriers would enable non-destructive resistive readout. However, the achievement of room-temperature polarization stability and switching at very low thickness is challenging. Here we use piezoresponse force microscopy at room temperature to show robust ferroelectricity down to 1 nm in highly strained BaTiO(3) films; we also use room-temperature conductive-tip atomic force microscopy to demonstrate resistive readout of the polarization state through its influence on the tunnel current. The resulting electroresistance effect scales exponentially with ferroelectric film thickness, reaching approximately 75,000% at 3 nm. Our approach exploits the otherwise undesirable leakage current-dominated by tunnelling at these very low thicknesses-to read the polarization state without destroying it. We demonstrate scalability down to 70 nm, corresponding to potential densities of >16 Gbit inch(-2). These results pave the way towards ferroelectric memories with simplified architectures, higher densities and faster operation, and should inspire further exploration of the interplay between quantum tunnelling and ferroelectricity at the nanoscale.