242 research outputs found

    Single-mode tunable erbium:ytterbium fibre Fabry-Perot laser

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    A compact tunable single-mode fiber laser is developed by using a novel combination of high-gain erbium: ytterbium (Er:Yb) phosphate fiber and fiber Fabry-Perot (FFP) cavity configurations. Experiments demonstrate the shortest Er:Yb phosphate FFP laser ever reported, which has a 100”m cavity length with a continuous wavelength tuning range over 4.52nm, as limited by the sharp fiber gain peak. In addition, an alternative 3-mirror laser design has also demonstrated single-mode lasing operation

    Spectroscopic and lasing characteristics of samarium-doped glass fibre

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    The fluorescence spectra of trivalent samarium doped glass fibres are described. In silica glass Sm3+ has a narrow fluorescence of 2.2 nm f.w.h.m. at a wavelength of 650 nm The influence of fluorescence line narrowing and large external electric fields on this line is reported. Visible laser emission is obtained at this wavelength when the fibre is pumped in a Fabry Perot cavity. The performance of the laser in continuous, Q-switched and self mode-locked operation is described. The basic theory of self-mode-locking is presented

    1.2dB/cm gain in an erbium:lutecium co-doped Al/P silica fibre

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    We report a peak gain of 1.2dB/cm at 1535nm in an Erbium:Lutecium codoped Al/P/Si fibre fabricated using a standard MCVD and solution doping technique. This is the highest gain per unit length yet reported in an erbium doped fiber amplifier. The incorporation of lutetium into the glass is shown to reduce the erbium ion clustering within the fiber

    Fabrication and characterisation of Er<sup>3+</sup>:Yb<sup>3+</sup> codoped phosphosilicate optical fibres for amplifiers and lasers

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    Sensitising erbium doped fibres with ytterbium significantly relaxes constraints in pump wavelength and device length. This makes versatile compact lasers and optical amplifiers operating at the important telecommunications window of 1.5”m a reality

    K(E10), Supergravity and Fermions

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    We study the fermionic extension of the E10/K(E10) coset model and its relation to eleven-dimensional supergravity. Finite-dimensional spinor representations of the compact subgroup K(E10) of E(10,R) are studied and the supergravity equations are rewritten using the resulting algebraic variables. The canonical bosonic and fermionic constraints are also analysed in this way, and the compatibility of supersymmetry with local K(E10) is investigated. We find that all structures involving A9 levels 0,1 and 2 nicely agree with expectations, and provide many non-trivial consistency checks of the existence of a supersymmetric extension of the E10/K(E10) coset model, as well as a new derivation of the `bosonic dictionary' between supergravity and coset variables. However, there are also definite discrepancies in some terms involving level 3, which suggest the need for an extension of the model to infinite-dimensional faithful representations of the fermionic degrees of freedom.Comment: 50 page

    The purified extract from the medicinal plant Bacopa monnieri, bacopaside II, inhibits growth of colon cancer cells in vitro by inducing cell cycle arrest and apoptosis

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    Published: 21 July 2018Aquaporin-1 (AQP1), a transmembrane pore-forming molecule, facilitates the rapid movement of water and small solutes across cell membranes. We have previously shown that bacopaside II, an extract from the medicinal herb Bacopa monnieri, blocks the AQP1 water channel and impairs migration of cells that express AQP1. The aim of this study was to further elucidate the anti-tumour potential of bacopaside II in colon cancer cells. Expression of AQP1 in HT-29, SW480, SW620 and HCT116 was determined by quantitative PCR and western immunoblot. Cells were treated with bacopaside II, and morphology, growth, autophagy, cell cycle and apoptosis assessed by time-lapse microscopy, crystal violet, acridine orange, propidium iodide (PI) and annexin V/PI staining respectively. AQP1 expression was significantly higher in HT-29 than SW480, SW620 and HCT116. Bacopaside II significantly reduced growth at ≄20 ”M for HT-29 and ≄15 ”M for SW480, SW620 and HCT116. Inhibition of HT-29 at 20 ”M was primarily mediated by G0/G1 cell cycle arrest, and at 30 ”M by G2/M arrest and apoptosis. Inhibition of SW480, SW620 and HCT116 at ≄15 ”M was mediated by G2/M arrest and apoptosis. These results are the first to show that bacopaside II inhibits colon cancer cell growth by inducing cell cycle arrest and apoptosis.Eric Smith, Helen M. Palethorpe, Yoko Tomita, Jinxin V. Pei, Amanda R. Townsend, Timothy J. Price, Joanne P. Young, Andrea J. Yool and Jennifer E. Hardingha