| 1. |
- Allaria, E., et al.
(author)
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Highly coherent and stable pulses from the FERMI seeded free-electron laser in the extreme ultraviolet
- 2012
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In: Nature Photonics. - 1749-4885. ; 6:10, s. 699-704
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Journal article (peer-reviewed)abstract
- Free-electron lasers (FELs) are promising devices for generating light with laser-like properties in the extreme ultraviolet and X-ray spectral regions. Recently, FELs based on the self-amplified spontaneous emission (SASE) mechanism have allowed major breakthroughs in diffraction and spectroscopy applications, despite the relatively large shot-to-shot intensity and photon-energy fluctuations and the limited longitudinal coherence inherent in the SASE mechanism. Here, we report results on the initial performance of the FERMI seeded FEL, based on the high-gain harmonic generation configuration, in which an external laser is used to initiate the emission process. Emission from the FERMI FEL-1 source occurs in the form of pulses carrying energy of several tens of microjoules per pulse and tunable throughout the 65 to 20 nm wavelength range, with unprecedented shot-to-shot wavelength stability, low-intensity fluctuations, close to transform-limited bandwidth, transverse and longitudinal coherence and full control of polarization.
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| 2. |
- Rocha, A. L., et al.
(author)
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Enoxacin induces oxidative metabolism and mitigates obesity by regulating adipose tissue miRNA expression
- 2020
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In: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 6:49
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Journal article (peer-reviewed)abstract
- MicroRNAs (miRNAs) have been implicated in oxidative metabolism and brown/beige adipocyte identity. Here, we tested whether widespread changes in miRNA expression promoted by treatment with the small-molecule enoxacin cause browning and prevent obesity. Enoxacin mitigated diet-induced obesity in mice, and this was associated with increased energy expenditure. Consistently, subcutaneous white and brown adipose tissues and skeletal muscle of enoxacin-treated mice had higher levels of markers associated with thermogenesis and oxidative metabolism. These effects were cell autonomous since they were recapitulated in vitro in m urine and human cell models. In preadipocytes, enoxacin led to a reduction of miR-34a-5p expression and up-regulation of its target genes (e.g., Fgfr1, Klb, and Sirt1), thus increasing FGF21 signaling and promoting beige adipogenesis. Our data demonstrate that enoxacin counteracts obesity by promoting thermogenic signaling and inducing oxidative metabolism in adipose tissue and skeletal muscle in a mechanism that involves, at least in part, miRNA-mediated regulation.
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| 3. |
- Garg, K. B., et al.
(author)
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Study of Sb substitution for Pr in the Pr0.67Ba0.33MnO3 system
- 2009
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In: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 321:4, s. 305-311
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Journal article (peer-reviewed)abstract
- We study the effect of Sb substitution for Pr in the hole-doped system Pr0.67Ba0.33MnO3 (PBMO) for different doping levels of Sb. The two electrical resistivity transitions observed in the pristine sample PBMO shift to low temperatures on Sb doping with an overall increase in the electrical resistivity. The significant local lattice distortion and the grain boundary effects caused by the large cation size mismatch between Pr3+ and Sb3+ suppresses the double-exchange (DE) interaction and enhances the super-exchange (SE) interaction. The compounds show a significant and increasing value of magnetoresistance at temperatures below the Curie temperature, not expected from the DE model. The Curie temperature decreases with increase in Sb content but the saturation magnetization is little affected by the substitution. The spins, however, stay well aligned in the low-temperature regime. Our X-ray near-edge absorption spectra (XANES) and core level photoemission (XPS) data clearly show the Sb cation to be in +3 state and rule out any possibility of e-doping in our compounds.
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| 4. |
- Sygletos, S., et al.
(author)
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Phase locking and carrier extraction schemes for phase sensitive amplification
- 2010
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In: 2010 12th International Conference on Transparent Optical Networks, ICTON 2010. - 9781424477975
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Conference paper (other academic/artistic)abstract
- We demonstrate two schemes which enable simultaneous phase locking, carrier extraction and frequency shifting for use in stand-alone phase sensitive amplifiers. The schemes provide phase locked pumps at appropriate frequency spacing for a number of non-degenerate PSA configurations. © 2010 IEEE.
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| 5. |
- Battiato, M., et al.
(author)
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Distinctive Picosecond Spin Polarization Dynamics in Bulk Half Metals
- 2018
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In: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 121:7
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Journal article (peer-reviewed)abstract
- Femtosecond laser excitations in half-metal (HM) compounds are theoretically predicted to induce an exotic picosecond spin dynamics. In particular, conversely to what is observed in conventional metals and semiconductors, the thermalization process in HMs leads to a long living partially thermalized configuration characterized by three Fermi-Dirac distributions for the minority, majority conduction, and majority valence electrons, respectively. Remarkably, these distributions have the same temperature but different chemical potentials. This unusual thermodynamic state is causing a persistent nonequilibrium spin polarization only well above the Fermi energy. Femtosecond spin dynamics experiments performed on Fe3O4 by time- and spin-resolved photoelectron spectroscopy support our model. Furthermore, the spin polarization response proves to be very robust and it can be adopted to selectively test the bulk HM character in a wide range of compounds.
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| 6. |
- Liu, S., et al.
(author)
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OTDM to WDM format conversion based on cascaded SHG/DFG in a single PPLN waveguide
- 2010
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In: Optics InfoBase Conference Papers. - Washington, D.C. : Optical Society of America (OSA).
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Conference paper (peer-reviewed)abstract
- We propose and experimentally demonstrate error-free OTDM to WDM format conversion based on cSHG/DFG within a 30mm-long PPLN waveguide and a time-to-frequency domain conversion approach, which relies upon switching a linearly chirped pulse.
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