Silver Nanoparticles Enhance Thermoluminescence and Photoluminescence Response in Li2B4O7 Glass Doped with Dy3+ and Yb3.

Lithium borate glass matrices doped with Dy3+ and Yb3+, containing silver nanoparticles in different concentrations are synthesized and characterized in this work. The Scanning Transmission Electron Microscopy confirms formation of silver nanoparticles in the samples. Absorption spectra of the samples show the presence of a broadband spectrum associated due to the surface plasmon effect of the silver nanoparticles. A strong surface plasmon band bellow 400 nm appears after the annealing process, due to the formation of silver nanoparticles with radius of 5-15 nm. The transition peaks of Dy3+ are also observed at 386, 446, 798, 917, 1088, 1265 and 1669 nm. Additionally, a large peak at 976 nm belonging to the absorption band corresponding to the Yb3+ is observed. Emission spectra under 406 nm pumping show two prominent bands at 506 and 590 nm belonging to the Dy3+ transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2, respectively. The fluorescence in the 480 nm and 525 nm spectral ranges enhanced with the silver nanoparticles contained in the samples. Is the first time, the luminescence studies of the lithium borate matrix doped with Dy3+ and Yb3+ containing silver nanoparticles is done. The basic parameters defining the lasing-amplifying potential of the glass matrices as a function of silver nanoparticles concentration are calculated. The Thermoluminescence response to UV irradiation also exhibits significant enhancement with the increment of silver nanoparticles in the samples.

[Seroprevalence of hepatitis C virus infection at the time of entry to prison in the prison population in the north-east of Spain]. / Seroprevalencia de infección por virus C de la hepatitis en población reclusa del noroeste de España a su ingreso en prisión. Grupo Noroeste para el estudio de la Hepatitis por Virus C en el medio penitenciario.

BACKGROUND: Spanish prisons have a high number of inmates whose behaviour puts them at risk of being infected by hepatitis C virus (HCV). The object of this study was to establish the prevalence of this infection and its associated factors in the prison population of the north-east of Spain. METHODS: Inmates in seven prisons in the north-east of Spain were studied. Socio-demographic and prison variables were gathered, as well as risk factors for infection by HCV. Antibodies against HCV were determined (EIA and INNO-LIA HCV III), Hepatitis B virus (VHB) (EIA), and human immunodeficiency virus (HIV) (EIA and Western-Blott). The analysis of associated factors was based on logistic regression. RESULTS: Of the total number of inmates studied, 47.9% presented HCV antibodies. There was greater prevalence in the case of the following: UDVP (89.6%); those who shared needles (94%); those infected by HIV (92.7%); carriers of Australia antigen (65.1%) and antibodies to the HBV core antigen (79.8%); those who had been in prison before (60.9%); unmarried men (54.8%); gypsies (52%); unqualified workers (50.4%); those who had no basic school qualifications (50.9%); those with tattoos (66.7%); and those with a background of self-inflicted injuries (79.3%). In the logistic regression analysis the variables associated to infection by HCV were: UDVP (OR = 33.3; I.C. 95% = 25-50), HBcAc (+) (OR = 4.1; I.C. 95% = 1.1-5.3), age (OR = 0.98; I.C. 95% = 0.96-1.00), months in prison (OR = 1.011; I.C. 95% = 1.004-1.019) and a background of previous prison sentences (OR = 2.3; I.C. 95% = 1.5-3.6). CONCLUSIONS: The prevalence of infection by HCV in prison inmates is very high. It is therefore recommended that preventive measures be increased (harm reduction programmes) and that clinical and analysis protocols be drawn up for those infected and for treatment in cases of chronic active hepatitis in order to control this serious public health problem.