Biomedical subjects
Publications and source records attributed to P Kefalas.
In this paper the behaviour of a bee colony is modelled as society of communicating agents acting in parallel and synchronising their behaviour. Two computational approaches for defining the agents behaviour are introduced and compared. Their common features as well as the complementary aspects making them suitable for merging together into a more complex model.
We have investigated the chemiluminescence signal of luminol and hydrogen peroxide in the presence of a transition metal (Co(II), Cu(I), Fe(II), Fe(III)) and of a chelator (EDTA, citric acid) in pH 8.5, 9 and 10 borate buffer solutions. We observed that the chemiluminescence intensities of these systems reached a plateau, where they remained stable for a period of 2-30 s. We also observed linearity between the intensity of chemiluminescence and the hydrogen peroxide concentration. The combination of Co(II) and EDTA at pH 9 was found to give the optimum signal with reference to time stability, intensity and reproducibility. Thus, compared to previous chemiluminescence applications, the present results permit us to propose a simple, enzyme-free and time-independent technique for the detection and quantification of hydrogen peroxide.
The scavenging activities of three standard antioxidants, quercetin, ascorbic acid, and trolox, were evaluated by Co(II)/ethylenediamine-tetraacetic acid (EDTA)-induced luminol chemiluminescence and the 2,2-diphenyl-1-picrylhydrazyl (DPPH*) free radical assay. Therefore, the aim of this study was to characterise an enzyme-free and time-independent chemiluminescence method for the assessment of the scavenging profile of compounds in a cell-free system using the Co(II)/EDTA-luminol-peroxide system. These results showed that the three standards were efficient and effective in inhibiting both Co(II)/EDTA-induced luminol chemiluminescence and the free radical DPPH*. For all the data obtained in this work, the scavenging activity for the standards tested decreased in the following order: quercetin > trolox > ascorbic acid. The present study has applied a simple and precise procedure for the study of hydroxyl radical scavenging activity by Co(II)/EDTA-induced luminol chemiluminescence, and this was assessed by DPPH* free radical scavenging.