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

Optical Tweezers And Multiphoton Microscopies Integrated Photonic Tool For Mechanical And Biochemical Cell Processes Studies

The research in biomedical photonics is clearly evolving in the direction of the understanding of biological processes at the cell level. The spatial resolution to accomplish this task practically requires photonics tools. However, an integration of different photonic tools and a multimodal and functional approach will be necessary to access the mechanical and biochemical cell processes. This way we can observe mechanicaly triggered biochemical events or biochemicaly triggered mechanical events, or even observe simultaneously mechanical and biochemical events triggered by other means, e.g. electricaly. One great advantage of the photonic tools is its easiness for integration. Therefore, we developed such integrated tool by incorporating single and double Optical Tweezers with Confocal Single and Multiphoton Microscopies. This system can perform 2-photon excited fluorescence and Second Harmonic Generation microscopies together with optical manipulations. It also can acquire Fluorescence and SHG spectra of specific spots. Force, elasticity and viscosity measurements of stretched membranes can be followed by real time confocal microscopies. Also opticaly trapped living protozoas, such as leishmania amazonensis. Integration with CARS microscopy is under way. We will show several examples of the use of such integrated instrument and its potential to observe mechanical and biochemical processes at cell level.6644Denk, W., Strickler, J.H., Webb, W.W., (1990) Science, 248, p. 73Xu, C., (1996) Proc. Natl. Acad. Sci. USA, 93, pp. 10-763Minami, T., Hirayama, S., (1990) J. Photochem. Photobiol. A - Chem, 53 (1), p. 11Lakowicz, J.R., Berndt, K.W., (1991) Rev. Scientific Instrum, 62 (7), p. 1727Becker, W., (2004) Microscopy Res. Technique, 63 (1), p. 58Ha, T., (1996) PNAS, 93 (13), p. 6264Gordon, G.W., (1998) Biophysical J, 74 (5), p. 2702Szavo, G., (1992) Biophysical J, 61 (3), p. 661Campagnola, P.G., (1999) Biophysical J, 77 (6), p. 3341J. X. Cheng JX and X. S. Xie, J. Physical Chem. B 108 (3): 827 (2004)M. Muller et al, J. Microscopy 197, 150 Part 2 (2000)Goksör, M., Enger, J., Hanstorp, D., Optical manipulation in combination with multiphoton microscopy for single-cell studies (2004) Applied Optics, 43 (25), p. 4831Ajito, K., Morita, M., (1999) Surf. Science, 428, p. 141Jess, P.R.T., Garces-Chavez, V., Smith, D., Mazilu, M., Paterson, L., Riches, A., Herrington, C.S., Dholakia, K., (2006) Opt. Express, 14 (12), p. 5779Fontes, A., Ajito, K., De Paula, A.M., Neves, A.R., Moreira, W.L., Barbosa, L.C., Cesar, C.L., (2003) Microsc. Microanal, 9 (SUPPL. 2), pp. 164-165A. Fontes, K. Ajito, A. A. R. Neves, W. L. Moreira, A. A. Thomaz, L. C. Barbosa, A. M. de Paula and C. L. Cesar, Phys. Rev. E. 72, 012903 (1-4) (2005)Fontes, A., Neves, A.A.R., Moreira, W.L., de Thomaz, A.A., Barbosa, L.C., de Paula, A.M., Cesar, C.L., (2005) Appl. Phys. Lett, 87, p. 22110

Positron Annihilation In Triphenylphosphine Oxide Complexes: Positronium Inhibition Mechanism Involving Excitation Of Charge Transfer States

Positronium formation in triphenylphosphine oxide and its lanthanide and hydrogen peroxide complexes have been characterized. The low probability of positronium formation observed has been attributed to a mechanism involving competition between charge transfer at large distances induced by the positron-molecular electron interaction and positronium formation during positron molecule scattering. The molecular site responsible for positronium formation has been identified. © 2008 Elsevier B.V. All rights reserved.4524-6249252Buckman, S.J., Sullivan, J.P., (2006) Nucl. Instr. Meth. Phys. Res. B, 247, p. 5Marler, J.P., Surko, C.M., (2005) Phys. Rev. A, 62, p. 062713(2003) Principles and Applications of Positron & Positronium Chemistry, , Jean Y.C., Mallon P.E., and Schrader D.M. (Eds), World Scientific, New Jersey, LondonMogensen, C.E., (1974) J. Chem. Phys., 60, p. 998Goworek, T., (1987) Phys. Stat. Sol., 9, p. 511(1995) Positron Spectroscopy of Solids, , Dupasquier A., and Mills Jr. A.P. (Eds), IOS Press, OhmsaMarques Netto, A., Máximo Bicalho, S.M.C., Filgueiras, C.A.L., Machado, J.C., (1985) Chem. Phys. Lett., 119, p. 507Klein, S.I., Barbieri, R.S., Marques Netto, A., Silva, M.E.S.R., Machado, J.C., (1990) J. Braz. Chem. Soc., 1, p. 80Marques Netto, A., Klein, S.I., Barbieri, R.S., Mauro, A.E., Magalhães, W.F., Machado, J.C., (1992) Mater. Sci. Forum, 105-110, p. 653Porto, A.O., Marques Netto, A., Magalhães, W.F., Carvalho, C.F., Machado, J.C., (1993) J. Phys.-Paris IV (Colloque C4, Supplément au Journal de Physique II), 3, p. 205Graúdo, J.E.J.C., Filgueiras, C.A.L., Marques-Netto, A., Batista, A.A., (2000) J. Braz. Chem. Soc., 11, p. 237Porto, A.O., Magalhães, W.F., Fernandes, N.G., Machado, J.C., (1997) Chem. Phys., 221, p. 199Machado, J.C., Porto, A.O., Carvalho, C.F., Magalhães, W.F., Maruqes-Netto, A., (1993) J. Phys. IV (Paris), 3, p. 201Porto, A.O., Magalhães, W.F., Machado, J.C., (1997) Chem. Phys. Lett., 266, p. 329Faustino, W.F., de Sá, G.F., Malta, O.L., Soares, M.C.F., Windmöller, D., Machado, J.C., (2006) Chem. Phys. Lett., 424, p. 63Machado, J.C., de Lima, G.M., Oliveira, F.C., Marzano, I.M., (2006) Chem. Phys. Lett., 418, p. 292Ito, Y., Suzuki, T., (2000) Radiat. Phys. Chem., 58, p. 743Perrin, D.D., Amarego, W.L.F., (1988) Purification of Laboratory Chemicals. third edn., , Pergamon Press, OxfordCopley, D.B., Fairbrother, F., Miller, J.R., Thompson, A.C., (1964) Proc. Chem. Soc. Sept., p. 300Cousins, D.R., Hart, F.A., (1967) J. Inorg. Nucl. Chem., 29, p. 1745Kirkegaard, P., Eldrup, M., (1974) Comput. Phys. Commun., 7, p. 401(1988) Studies in Physical and Theoretical Chemistry 57: Positron and Positronium Chemistry, , Schrader D.M., and Jean Y.C. (Eds), Elsevier, Amsterdam (Chapter 4)Faustino, W.M., Malta, O.L., de Sá, G.F., (2006) Chem. Phys. Lett., 429, p. 595Faustino, W.M., Malta, O.L., Teotônio, E.E.S., Brito, H.F., Simas, A.M., de Sá, G.F., (2006) J. Phys. Chem. A, 110, p. 2510Baures, P.W., Silverton, J.V., (1990) Acta Cryst. C, 46, p. 71

Study Of Optically Trapped Living Trypanosoma Cruzi/trypanosoma Rangeli - Rhodnius Prolixus Interactions By Real Time Confocal Images Using Cdse Quantum Dots

One of the fundamental goals in biology is to understand the interplay between biomolecules of different cells. This happen, for example, in the first moments of the infection of a vector by a parasite that results in the adherence to the cell walls. To observe this kind of event we used an integrated Optical Tweezers and Confocal Microscopy tool. This tool allow us to use the Optical Tweezers to trigger the adhesion of the Trypanosoma cruzi and Trypanosoma rangeli parasite to the intestine wall cells and salivary gland of the Rhodnius prolixus vector and to, subsequently observe the sequence of events by confocal fluorescence microscopy under optical forces stresses. We kept the microorganism and vector cells alive using CdSe quantum dot staining. Besides the fact that Quantum Dots are bright vital fluorescent markers, the absence of photobleaching allow us to follow the events in time for an extended period. 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Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background: Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods: The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results: A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion: Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)