Quantum Confinement Effects On The Phonons Of Pbte Quantum Dots In Tellurite Glasses

We present Raman-scattering results for PbTe quantum dots (QDs) in doped telluride glasses which clearly show the confinement effects on the phonon spectra as a function of the quantum-dot size..6892Kraus and F. Wise;Phys. Rev. Lett. 79 (25), 5102-05 (1997)Thoen, E.R., (1998) Appl, Phys. Lett, 73 (15), p. 2149Wise, F., (2000) Ace. Chem. Res, 33, pp. 773-780Tsuda, S., Cruz, C.H.B., (1991) Opt. Lett, 16, p. 1596Nakamura, A., Tokizaki, T., Akiyama, H., Kataoka, T., (1992) J. Lumin, 53, p. 105Ohtsuka, S., Koyama, T., Tsunetomo, K., Nagata, H., Tanaka, S., (1992) Appl. Phys. Lett, 61, p. 2953Tsunetomo, K., Ohtsuka, S., Koyama, T., Tanaka, S., Sasaki, F., Kobayashi, S., (1995) Nonlin. Opt, 13, p. 109Colvin, V.L., Schlamp, M.C., Alivisatos, A.P., (1995) Nature ∼London, 370, p. 354Dabbousi, M., Bawendi, G., Onitsuka, O., Rubner, M.F., (1995) Appl. Phys. Lett, 66, p. 1316Guerreiro, T., Ten, S., Borrelli, N.F., Butty, J., Jabbour, G.E., Peyghambarian, N., (1997) Appl. Phys. Lett, 71, p. 1595Murray, C.B., Kagan, C.R., Bawendi, M.G., (1995) Science, 270, p. 1335Kang, I., Wise, F.W., (1997) J. Opt. Soc. Am. B, 14, p. 1632Reynoso, V.C.S., de Paula, A.M., Cuevas, R.F., Medeiros Neto, J.A., Alves, O.L., Cesar, C.L., Barbosa, L.C., (1995) Electron. Lett, 31, p. 1013G.J.Jacob, C.L.Cesar,L.C.Barbosa, Chem.Phys.Glass 43C (2002)250-252Esch, V., Fluegel, B., Khitrova, G., Gibbs, H.M., Jiajin, X., Kang, K., Koch, S.W., Peyghambarian, N., (1990) Phys. Rev, B42, p. 7450Sercel, P.C., Valhala, K.J., (1990) Phys. Rev, B42, p. 3690Schoenlein, R.W., Mittleman, D.M., Shiang, J.J., Alivisatos, A.P., Shank, C.V., (1993) Phys. Rev. Lett, 70, p. 1014Ekimov, A.I., Hache, F., Schanne-Klein, M.C., Ricard, D., Flytzanis, C., Kudryavtsev, I.A., Yazeva, T.V., Efros, A.L., (1993) J. Opt. Soc. Am, B10, p. 100Norris, D.J., Sacra, A., Bawendi, C.B.M.M.G., (1994) Phys. Rev. Lett, 72, p. 2612de Oliveira, C.R.M., de Paula, A.M., Filho, F.O.P., Neto, J.A.M., Barbosa, L.C., Alves, O.L., Menezes, E.A., Cesar, C.L., (1995) Appl. Phys. Lett, 66, p. 439R. Ruppin and R. Englman, Rep. Prog. Phys. 33, 149 (1970)R. Ruppin, J. Phys. C: 8, 1969 (1975)Thoen, E.R., Steinmeyer, G., Langlois, P., Ippen, E.P., Tudury, G.E., Brito Cruz, C.H., Barbosa, L.C., Cesar, C.L., (1998) Appl. Phys. Lett, 73Krauss, T.D., Wise, F.W., Coherent and Acoustical Phonon in a Semiconductor Quantum DotsPhis (1997) Rev. Lett, 79, pp. 5102-510

Pbte Quantum Dots In Tellurite Glass Microstructured Optical Fiber

PbTe doped tellurite glass photonic optical fiber for non linear application were developed using rod in tube method in a draw tower. We follow the growth kinetics of the quantum dots in the optical fiber by High Resolution Transmission Electron Microscopy giving some results related with the growth kinetic of the same in function of time so much for optical fiber as for the glass bulk. Absorption peak near 1500 nm as observed and it was attributed the optical resonance due PbTe quantum dots in the core fiber.6902Tsunetomo, K., (1995) Nonlinear Opt, 13, p. 109Borrelli, N.F., Smith, D.W., (1994) J. Non-Cryst. Soi, 180, p. 25Lipovskii, A., Kolobkova, E.A., Petrikov, V., Kang, I., Olkhovets, A., Krauus, T., Thomas, M., Kycia, S., (1997) Appl. Phys. Lett, 71, p. 3406Reynoso, V.C.S., de Paula, A.M., Cuevas, R.F., Medeiros Neto, J.A., Alves, O.L., Cesar, C.L., Barbosa, L.C., (1995) Elect. Lett, 31 (12), pp. 1013-1014Rodrigues, E., Jimenez, E., Jacob, G.J., Neves, A.A.A., Cesar, C.L., Barbosa, L.C., (2005) Phisica E, 26, pp. 321-325Jacob, G.J., Cesar, C.L., Barbosa, L.C., Tellurite Glass Doped with PbTe Quantum Dots (2002) Physics and Chemistry of Glass, 43 C, pp. 250-253Jacob, G.J., Rodriguez, E., Barbosa, L.C., Cesar, C.L., Tellurite Glass Optical fiber doped with PbTe Quantum DotsPhotonics West 2005, The International Society for Optical Engineering SPIEEnomoto, Y., Tokuyama, M., Kawasaki, K., (1986) Act. Metall, 34, p. 2139Marqusee, J.A., Ross, J., (1984) J. Chem. Phys, 80, p. 536Lifshitz, E.M., Slyozov, V.V., (1961) J. Phys. Chem. Sol, 19, p. 3

Differential gene expression and immunolocalization of platelet-derived growth factors and their receptors in caprine ovaries

AbstractThis study evaluated the messenger RNA (mRNA) expression and immunolocalization of all members of the platelet-derived growth factor (PDGF) family in caprine ovaries by quantitative PCR and immunohistochemistry, respectively. Detectable levels of PDGF-A mRNA were not observed in primordial follicles. Higher levels of PDGF-B mRNA were observed in primary follicles than in primordial follicles (P < 0.05). PDGF-D mRNA levels were higher in secondary follicles than in the other preantral follicle categories (P < 0.05). PDGF-B mRNA expression was higher than PDGF-C mRNA expression in primary follicles (P < 0.05). In antral follicles, PDGF-A mRNA expression was higher in cumulus-oocyte complexes (COCs) from small antral follicles than in those from large antral follicles and their respective granulosa/theca (GT) cells (P < 0.05). Furthermore, in COCs from small and large antral follicles, PDGF-A mRNA expression was higher than that of the other PDGF isoforms (P < 0.05). The mRNA levels of PDGF-B and PDGF-D and PDGFR-α and PDGFR-β were higher in GT cells from large antral follicles than in GT cells from small antral follicles and in their respective COCs (P < 0.05). In COCs and GT cells from small antral follicles, the mRNA levels of PDGFR-α were higher than those of PDGFR-β (P < 0.05). All proteins were observed in the cytoplasm of oocytes from all follicular categories. In granulosa cells, all PDGFs and PDGFR-β were detected from starting at the secondary stage, and in theca cells, all proteins, except PDGF-C, were detected starting at the antral stage. In conclusion, PDGF and its receptors are differentially expressed in the oocytes and ovarian cells according to the stage of follicular development, suggesting their role in the regulation of folliculogenesis in goats

Tellurite Photonic Crystal Fiber With Er3+-tm3+ For Broadband Optical Amplifier In 1550nm

Er3+-Tm3+ co-doped tellurite photonic crystal fiber was fabricated via a stack-and-draw procedure and without using extrusion in any stage. The final fiber presents a 187 nm bandwidth of amplified spontaneous emission (ASE) intensity around 1550nm when pumped with 790nm. In this manuscript a soft-glass tube fabrication technique, using the centrifugation method, is also shown.6116Knight, J.C., Birks, T.A., Russel, P.St.J., Atkin, D.M., All-silica single-mode optical fiber with photonic crystal cladding (1996) Opt. Lett, 21, pp. 1547-1549Jeong, H., Oh, K., Han, S.R., Morse, T.F., Characterization of broadband amplified spontaneous emission from an Er3+-Tm3+ -codoped silica fiber (2003) Opt. Lett, 367, pp. 507-511Chillcce, E.F., Rodriguez, E., Neves, A.A.R., Moreira, W.C., César, C.L., Barbosa, L.C., Er3+-Tm3+ co-doped tellurite fibers for broadband optical fiber amplifier around 1550 nm band (2005) Opt. Fiber Technol., , article in pressRussell, P., Photonic crystal fibers (2003) Science, 299, pp. 358-362Knight, J.C., Photonic crystal fibers (2003) Nature, 424, pp. 847-851Kumar, V.V.R.K., George, A.K., Knight, J.C., Russell, P.St.J., Tellurite photonic crystal fiber (2003) Opt. Exp, 20, pp. 2641-2645Kumar, V.V.R.K., George, A.K., Reeves, W.H., Knight, J.C., Russell, P.St.J., Omenetto, F.G., Taylor, A.J., Extruded soft glass photonic crystal fiber for ultrabroad supercontinuum generation (2002) Opt. Exp, 10 (25), pp. 1520-1525Kiang, K.M., Frampton, K., Monro, T.M., Moore, R., Tucknott, J., Hewak, D.W., Richardson, D.J., Rutt, H.N., Extruded singlemode non-silica glass holey optical fiber (2002) Electron. Lett, 38 (12), pp. 546-54

Exceptionally Slow Rise in Differential Reflectivity Spectra of Excitons in GaN: Effect of Excitation-induced Dephasing

Femtosecond pump-probe (PP) differential reflectivity spectroscopy (DRS) and four-wave mixing (FWM) experiments were performed simultaneously to study the initial temporal dynamics of the exciton line-shapes in GaN epilayers. Beats between the A-B excitons were found \textit{only for positive time delay} in both PP and FWM experiments. The rise time at negative time delay for the differential reflection spectra was much slower than the FWM signal or PP differential transmission spectroscopy (DTS) at the exciton resonance. A numerical solution of a six band semiconductor Bloch equation model including nonlinearities at the Hartree-Fock level shows that this slow rise in the DRS results from excitation induced dephasing (EID), that is, the strong density dependence of the dephasing time which changes with the laser excitation energy.Comment: 8 figure

Study of K0∗(1430)K^*_0(1430) and a0(980)a_0(980) from B→K0∗(1430)πB\to K^*_0(1430)\pi and B→a0(980)KB\to a_0(980)K Decays

We use the decay modes $B \to K^*_0(1430) \pi$ and $B \to a_0(980) K$ to study the scalar mesons $K^*_0(1430)$ and $a_0(980)$ within perturbative QCD framework. For $B \to K^*_0(1430) \pi$, we perform our calculation in two scenarios of the scalar meson spectrum. The results indicate that scenario II is more favored by experimental data than scenario I. The important contribution from annihilation diagrams can enhance the branching ratios about 50% in scenario I, and about 30% in scenario II. The predicted branching ratio of $B \to a_0(980) K$ in scenario I is also less favored by the experiments. The direct CP asymmetries in $B \to K^*_0(1430) \pi$ are small, which are consistent with the present experiments.Comment: More references are added. Published Versio

Development Of Soft-glasses Photonic Crystal Fiber Made By Stacking-and-draw Technique

We have been able to produce soft glass conventional core-clad and micro-structured fibers using rod-and-tube and stack-and-draw method respectively. The stack-and-draw technique shows several difficulties when used with soft glasses, that we managed to avoid using two different lead and alkaline glasses. Non commercial glasses and fibers were thermo-mechanically and optically characterized.6469White, T.P., McPhedran, R.C., de Sterke, C.M., Botten, L.C., Steel, M.J., Confinement losses in micro structure optical fibers (2001) Opt. Lett, 26 (21), p. 1660Russell, P., Photonic crystal fibers (2003) Science, 299, pp. 358-362Knight, J.C., Photonic crystal fibers (2003) Nature, 424, pp. 847-851Chillcce, E.F., Cordeiro, C.M., Rodriguez, E., Brito Cruz, C.H., Cesar, C.L., Barbosa, L.C., Tellurite photonic crystal with Er 3+-Tm3+ for broadband optical amplifier in 1550nm (2006) Proc. of SPIE, 6116, p. 611604A. Hruby, Czech J. Phys. B, Evaluation of glass-forming tendency by means of DTA 1972, 22, 118