Radiation Safety
Living creatures contain both hydrophobic and hydrophilic compounds, any of which may be labeled during the course of a radioactive experiment. As discussed in earlier sections, the best solvents for scintillation counting are the aromatic…
While the effectiveness of a scintillation cocktail may be expressed a number of ways, it is most often given as the percentage of emission events that produce a detectable pulse of photons, referred to as…
A beta particle, passing through a scintillation cocktail, leaves a trail of energized solvent molecules. These excited solvent molecules transfer their energy to scintillator molecules, which give off light. Each scintillator molecule gives off only…
Radioactive decay occurs with the emission of particles or electromagnetic radiation from an atom due to a change within its nucleus. Forms of radioactive emission include alpha particles (α), beta particles (β), and gamma rays…
In at least one important way, measuring hydrogen peroxide is substantially easier than measuring superoxide. Superoxide is unstable in aqueous solution—its steady state concentration cannot be measured directly. As a result, superoxide “levels” must be…
Hydrogen peroxide, like superoxide, can react with a variety of targets in the cell, and has been associated with a number of diseases. Aerobic organisms express catalase and peroxidase enzymes to prevent damage by H2O2.…
Overview Superoxide has been implicated in diseases ranging from Alzheimer’s to diabetes. The wide range of pathologies associated with superoxide is the result of its ability to react with a variety of cellular targets, including…
Oxygen is used by a great variety of organisms as a means for producing energy. The redox potential of the oxygen-water couple is 1.229 Volts, meaning that a relatively large amount of energy is released…
Although secondary fixation in osmium tetroxide provides some areas of electron density, this is usually not sufficient to provide high contrast, high definition images. A number of staining techniques are available to enhance the contrast…
The ultrathin sections required in TEM are cut with knives of glass, diamond or sapphire. These materials produce extremely hard, ultrasharp edges, but they are brittle and subject to damage. Glass knives are produced as…