Polymer Light Emitting Diode Using PFT-Poly(9,9 `-n-dihexil-2,7-fluorenodiilvinylene-alt-2,5thiophene)

The development of new electroluminescence polymers for specific colour tuning in Polymer Light Emitting Devices (PLEDs) is currently one of the most important fields for organic electronics. This work reports a synthesis of a new electroluminescent polymer and the concomitant test as PLED emissive layer. The polymer, synthesised from fluorene, is poly(9,9`-n-dihexil-2,7-fluorenodiilvinylene-alt-2,5thiophene) or PFT The luminescence shows large bands with maxima around 480 nm in absorption and 560 nm in emission. The device was made in a three layer structure, with PEDOT:PSS as hole transport layer, PFT as emissive layer and butyl-PBD as electron transport layer. The electroluminescence spectrum shows a strong band peaked at 540 nm. For an applied voltage of 12 Volt, the brightness at normal angle of viewing is near 10 cd/m(2) and the luminous efficiency is of 0.01 lm/W. A discussion about carrier transport and the electroluminescence properties is made.

Influence of Molecular Dynamics on the Dielectric Properties of Poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) -Based Devices

This paper uses Nuclear Magnetic Resonance (NMR) and Differential Scanning Calorimetry (DSC) techniques to study the molecular relaxations and phase transitions in poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT), which has been extensively studied as the active thin film in organic devices. Besides the identification of the glass transition, beta relaxation and crystal-to-crystal phase transition, we correlate such phenomena with dielectric and transport mechanisms in diodes with F8BT as the active layer. The beta relaxation has been assigned to a transition at about 210 K measured by H-1 and C-13 solid state NMR, and can be attributed to local motions in the side chains. The glass transition has been detected by DSC and H-1 NMR. Dielectric spectroscopy (DS) carried out at low frequencies on diodes made from F8BT show two peaks which are coincident with the above transitions. This allowed us to correlate the electrical changes in the film with the onset of specific molecular motions. In addition, DS indicates a third peak related with a crystal-to-crystal phase transition. Finally, these transitions were correlated with changes in the carrier mobility recorded in thin films and published recently.

Rangelia vitalii: changes in the enzymes ALT, CK and AST during the acute phase of experimental infection in dogs

Rangelia vitalii is a protozoon that causes diseases in dogs, and anemia is the most common laboratory finding. However, few studies on the biochemical changes in dogs infected with this protozoon exist. Thus, this study aimed to investigate the biochemical changes in dogs experimentally infected with R. vitalii, during the acute phase of the infection. For this study, 12 female dogs (aged 6-12 months and weighing between 4 and 7 kg) were used, divided in two groups. Group A was composed of healthy dogs (n = 5); and group B consisted of infected animals (n = 7). Blood samples were collected on days 0, 10, 20 and 30 after infection, using tubes without anticoagulant to obtain serum and analyze the biochemical parameters. An increase in alanine aminotransferase (ALT) on day 20 (P < 0.05) was observed. Also, increased creatine kinase (CK) and aspartate aminotransferase (AST) levels were observed throughout the experimental period (P < 0.05). No changes in the serum gamma-glutamyltransferase, urea and creatinine levels were observed. Thus, is possible to conclude that experimental infection with R. vitalii in dogs causes changes to the biochemical profile, with increased ALT, AST and CK enzyme levels.

The evolution of health status and chronic conditions in Catalonia, 1994-2006: the paradox of health revisited using the Blinder - Oaxaca decomposition

[EN] Background: The paradox of health refers to the improvement in objective measures of health and the increase in the reported prevalence of chronic conditions. The objective of this paper is to test the paradox of health in Catalonia from 1994 to 2006. Methods: Longitudinal cross-sectional study using the Catalonia Health Interview Survey of 1994 and 2006. The approach used was the three-fold Blinder - Oaxaca decomposition, separating the part of the differential in mean visual analogue scale value (VAS) due to group differences in the predictors (prevalence effect), due to differences in the coefficients (severity effect), and an interaction term. Variables included were the VAS value, education level, labour status, marital status, all common chronic conditions over the two cross-sections, and a variable for non-common chronic conditions and other conditions. Sample weights have been applied. Results: Results show that there is an increase in mean VAS for men aged 15-44, and a decrease in mean VAS for women aged 65-74 and 75 and more. The increase in mean VAS for men aged 15-44 could be explained by a decrease in the severity effect, which offsets the increase in the prevalence effect. The decrease in mean VAS for women aged 65-74 and 75 and more could be explained by an increase in the prevalence effect, which does not offset the decrease in the severity effect. Conclusions: The results of the present analysis corroborate the paradox of health hypothesis for the population of Catalonia, and highlight the need to be careful when measuring population health over time, as well as their usefulness to detect population's perceptions.

Estudio epidemiológico de la incidencia del hongo Alternaria alternata en la isla de Gran Canaria y rentabilidad clínica del diagnóstico de su alérgeno mayor Alt a 1

Programa de doctorado: Avances en medicina interna