Spontan pulsierendes Auge

Ohne Zusammenfassung     

A theoretical model evaluating the angular distribution of luminescence emission in X-ray scintillating screens.

The aim of this study was to examine the angular distribution of the light emitted from radiation-excited scintillators in medical imaging detectors. This distribution diverges from Lambert's cosine law and affects the light emission efficiency of scintillators, hence it also affects the dose burden to the patient. In the present study, the angular distribution was theoretically modeled and was used to fit experimental data on various scintillator materials. Results of calculations revealed that the angular distribution is more directional than that predicted by Lambert's law. Divergence from this law is more pronounced for high values of light attenuation coefficient and thick scintillator layers (screens). This type of divergence reduces light emission efficiency and hence it increases the incident X-ray flux required for a given level of image brightness.     

Magnesium therapy in acoustic trauma.

Acoustic trauma is one of the major causes of hearing loss and tinnitus, particularly in industrial environments. Noise-induced hearing loss (NIHL) results in direct mechanical damage as well as in indirect metabolic processes. Metabolic disorders have multiple origins: ionic, ischemic, excitotoxic and production of cochlear free radicals causing cell death, due to necrosis or apoptosis. The efficacy of magnesium, administered either to prevent or to treat NIHL has been demonstrated in several studies in animals and in humans. Magnesium, which easily crosses the hematocochlear barrier, presents neuroprotective and vasodilatory effects, and thus, is able to limit the cochlear damage. Magnesium therapy is well documented because it is usually prescribed in other pathologies. Its side effects and contraindications are few and it is cheap. This article presents also some arguments that emphasize the interest of magnesium therapy in acoustic trauma.     

A study of the relationship between the fever caused by bacterial pyrogens and the fever accompanying acute infections

The relationship between the fever of acute infection and that following injection of bacterial pyrogen was studied by administering pyrogens to animals convalescent from acute infections. Rabbits surviving dermal pneumococcal infections or peritonitis due to Escherichia coli were given intravenous injections of typhoid or E. coli vaccine. They showed no evidence of tolerance to the fever-promoting effect of these pyrogenic materials. Tolerance did develop in infected animals given daily pyrogen injections during the course of the infection. Certain previous observations upon the ability of rabbits to develop tolerance to pyrogens, the broad nature of the tolerance, and its duration were confirmed. It is concluded that the pyrogen produced by certain bacteria plays little or no r?le in the production of the fever of infection. These findings are compatible with the hypothesis that there is a common factor, perhaps a product of cell injury, underlying the fever accompanying diseases of various types.     

Multivariate comparison of elemental concentrations in human teeth

R-mode factor analysis was applied to characterize the chemical composition of human teeth investigated by particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and X-ray fluorescence (XRF) techniques. The approach developed in this study enabled the separation between essential mineral teeth components and the pollutants deposited in teeth tissues during the human life. The three independent sources of metals incorporated in human teeth were found. The first source, representing about 43% of the variance of the concentration data, was characterized by pollutant elements of power industry emissions. The second factor was loaded with toxic elements of general urban pollution. The third factor represented the tooth source as it contained mainly large fractions of the mineral components of the tooth tissue as Ca and K.