Luminescent properties of Bi-doped polycrystalline KAlCl4

We observed an intensive near-infrared luminescence in Bi-doped KAlCl4 polycrystalline material. Luminescence dependence on the excitation wavelength and temperature of the sample was studied. Our experimental results allow asserting that the luminescence peaked near 1 um belongs solely to Bi+ ion which isomorphically substitutes potassium in the crystal. It was also demonstrated that Bi+ luminescence features strongly depend on the local ion surroundings

Uracil DNA N-Glycosylase Promotes Assembly of Human Centromere Protein A

Uracil is removed from DNA by the conserved enzyme Uracil DNA N-glycosylase (UNG). Previously, we observed that inhibiting UNG in Xenopus egg extracts blocked assembly of CENP-A, a histone H3 variant. CENP-A is an essential protein in all species, since it is required for chromosome segregation during mitosis. Thus, the implication of UNG in CENP-A assembly implies that UNG would also be essential, but UNG mutants lacking catalytic activity are viable in all species. In this paper, we present evidence that UNG2 colocalizes with CENP-A and H2AX phosphorylation at centromeres in normally cycling cells. Reduction of UNG2 in human cells blocks CENP-A assembly, and results in reduced cell proliferation, associated with increased frequencies of mitotic abnormalities and rapid cell death. Overexpression of UNG2 induces high levels of CENP-A assembly in human cells. Using a multiphoton laser approach, we demonstrate that UNG2 is rapidly recruited to sites of DNA damage. Taken together, our data are consistent with a model in which the N-terminus of UNG2 interacts with the active site of the enzyme and with chromatin

New materials, regimes and applications of fibre laser techonology

We demonstrate mode-locking fibre laser operating in the infrared spectral region. Ultrashort pulse lasers are used as pump sources for nonlinear process investigation, including supercontinuum generation and sum-frequency generation. © OSA 2014

Erbium-doped fibers based on cesium-silicate glasses

Using modified chemical vapor deposition and solution doping techniques, erbium-doped fibers (EDFs) were prepared based on cesium-silicate glasses. The possibility of manufacturing high-concentration (1-13 wt%) EDFs was shown, and a fiber structure was realized by means of direct doping of cesium-silicate glass with erbium ions. The optical, fluorescence, and gain properties of prepared samples were examined. A maximum gain of 25 dB at 1538 nm was achieved in the fiber at an optimum length of 30 cm at a pump power of 50 mW at 979 nm. (C) 2000 Academic Press.61616