2 resultados para Light intensity
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)
Resumo:
Neodymium doped yttrium aluminoborate and yttrium calcium borate glasses were prepared by the conventional melting-quenching technique with neodymium concentration varying from 0.10 to 1.0 mol%. The obtained glasses present a wide transparency in the UV-visible region (till 240 nm). The thermoluminescent (TL) emission of beta-irradiated samples was measured, showing a broad peak at similar to 240 degrees C with intensities related to the Nd(3+) content, for both glasses. Calcium borate glass samples are about one order of magnitude less luminescent than the aluminoborate glasses. Probably the presence of Ca(2+), instead of Al(3+) and Y(3+) in the matrix, inhibits the production of the intrinsic hole centers. connected to boron and oxygen, known in the literature to act as luminescent centers in TL emission of borate glasses. We suggest that Nd(3+) ions act as electron trapping centers in both glass matrices, as they modify the temperature of emission and the light intensity. Also, the Nd:YAIB glass can be used as a dosimeter in various applications, including radiotherapy. but the sensitivity of this material to neutron should be checked. (C) 2008 Elsevier B.V. All rights reserved.
Resumo:
In the last years, phototherapy has becoming a promising tool to improve skeletal muscle recovery after exercise, however, it was not compared with other modalities commonly used with this aim. In the present study we compared the short-term effects of cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) with placebo LEDT on biochemical markers related to skeletal muscle recovery after high-intensity exercise. A randomized double-blind placebo-controlled crossover trial was performed with six male young futsal athletes. They were treated with CWIT (5A degrees C of temperature [SD +/- 1A degrees]), active LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW of output power, 30 s of irradiation time per point, and 41.7 J of total energy irradiated per point, total of ten points irradiated) or an identical placebo LEDT 5 min after each of three Wingate cycle tests. Pre-exercise, post-exercise, and post-treatment measurements were taken of blood lactate levels, creatine kinase (CK) activity, and C-reactive protein (CRP) levels. There were no significant differences in the work performed during the three Wingate tests (p > 0.05). All biochemical parameters increased from baseline values (p < 0.05) after the three exercise tests, but only active LEDT decreased blood lactate levels (p = 0.0065) and CK activity (p = 0.0044) significantly after treatment. There were no significant differences in CRP values after treatments. We concluded that treating the leg muscles with LEDT 5 min after the Wingate cycle test seemed to inhibit the expected post-exercise increase in blood lactate levels and CK activity. This suggests that LEDT has better potential than 5 min of CWIT for improving short-term post-exercise recovery.