The method can be combined with epi-fluorescence microscopy. The molecular states of the fluorophore can be expressed by a three-state energy model. This leads to a set of differential Crizotinib
equations which describe the photobleaching behavior of fluorescein. The numerical solution of these equations shows that in a conventional wide-field fluorescence microscope, the fluorescence of fluorescein will fade out faster at low than at high oxygen concentration. Further simulation showed that a simple ratio function of different time-points during a fluorescence decay recorded during photobleaching could be used to describe oxygen concentrations in an aqueous solution. By careful choice of dye concentration and excitation light intensity the sensitivity in the oxygen concentration range of interest can be optimized. In the simulations, the estimation of oxygen concentration by the ratio function was very little affected by the pH value in the range of pH 6.5�C8.5. Filming the fluorescence decay by a charge-coupled-device (ccd) camera mounted on a fluorescence microscope allowed a pixelwise Apitolisib order
estimation of the ratio function in a microscopic image. Use of a microsensor and oxygen-consuming bacteria in a sample chamber enabled the calibration of the system for quantification of absolute oxygen concentrations. The method was demonstrated on nitrifying biofilms growing on snail and mussel shells, showing clear effects of metabolic activity on oxygen concentrations. Microsc. Res. Tech. 77:341�C347, 2014. ? 2014 Wiley Periodicals, Inc. ""The aim of this study was to evaluate the persistence of resin cement residues after dentin surface cleaning with different alcohol-based solutions or an essential oil learn more
(eucalyptol). Forty bovine teeth were sectioned in order to expose pulp chamber dentin to be washed with 1.0 mL of 2.5% sodium hypochlorite (NaOCl), followed by 0.1 mL of 17% EDTA application for 3 min, and final irrigation with 2.5% NaOCl. The specimens were air dried and resin-based cement was rubbed onto the dentine surface with a microbrush applicator. After 15 min, the surface was scrubbed with a cotton pellet and moistened with different dentin cleaning solutions, compounding the following groups: G1��95% ethanol, G2��70% ethanol, G3��70% isopropyl alcohol, or G4��eucalyptol. The dentin was scrubbed until the cement residues could not be visually detected. Sections were then processed for SEM and evaluated at ��500 magnification. Scores were attributed to each image according to the area covered by residual sealer, and data were subjected to Kruskal�CWallis at 5% significance. Eucalyptol promoted the most adequate dentin cleaning, although no statistical difference was detected amongst the groups (P > 0.05), except between the eucalyptol and 70% ethanol groups (P < 0.05).