RESUMO
Graphene is a very promising material for electronics applications. In recent years, its sensitivity to ultraviolet (UV) irradiation has been studied extensively. However, there is no clear answer to the question, which factor has a key influence on the sensitivity of graphene to UV. In order to check the influence of the final substrate on the electrical response, graphene transferred on polymeric and non-polymeric substrate was investigated. To achieve this goal three polymeric and three non-polymeric substrates were tested. The results of the preliminary tests indicated the different character of the reaction on UV irradiation in each of group. To explain the reason of the difference, the complementary studies were done. The samples that were resistant to high temperature were annealed in a vacuum at 500 °C to get rid of water trapped between graphene and the substratum. The samples after annealing reacted less dynamically to UV irradiation. Moreover, the progress of changes in electrical response of the annealed samples had a similar character to the polymeric substrates, with the hydrophobic nature of the surface. These studies clearly prove that the sensitivity of graphene to UV irradiation is influenced by water trapped under the graphene.
RESUMO
Systemic lupus erythematosus is an autoimmune, multiorgan disease, in the course of which central nervous system (CNS) disturbances are usually observed. Pathomechanism of CNS changes is complex and not fully investigated. Neuropathological alterations are often not characteristic, usually caused by vasculopathy, infarction, hemorrhages or infection. Vascular changes are generally disseminated and develop in different time period, sometimes they precede clinical symptoms. Currently applied diagnostic methods and their usefulness in diagnosis of CNS involvement in lupus patients, especially single photon emission computed tomography (SPECT), are presented.
