Prasunpriya Nayak, Shiv Sharma and Nadella Chowdary
Impact of Coexposure to Aluminum and Ethanol on Phosphoesterases and Transaminases of Rat Cerebrum
Ubiquitous presence along with uncontrolled use of aluminum and increasing trends of ethanol consumption in India increased the chance of coexposure to aluminum and ethanol. Possibilities are there, that both of them follow common mechanisms to produce neurotoxicity. The phosphomonoesterases and glutamate transaminases are studied in rat brain cerebrum after combined exposure to aluminum and varied doses of ethanol for 4 weeks. Dose dependent decreases in growth have been observed. The impact of aluminum on cerebral acidic and alkaline phosphomonoesterases activities were shown to be altered in a dose dependent fashion by the coexposure to ethanol. Aspartate aminotransferase and alanine aminotransferase of the cerebrum were responding differentially to aluminum exposure in the presence of different doses of ethanol exposure. It has been suggested that the ethanol-induced augmentation of impacts of aluminum on the cerebrum is dose dependent and there might be a critical level of ethanol exposure for the observed effect on cerebrum.
The influence of electron-phonon interaction on the shape of the optically stimulated luminescence decay curve of Al2O3:C has been studied using thermally assisted optically stimulated luminescence (TA-OSL). The minimum detectable dose (MDD) of a phosphor depends on the standard deviation of the background signal which affects the signal-to-noise ratio. The standard deviation of the background signal reduces at lower stimulation light intensity while the readout time increases. Further, measurement at higher temperature enhances the OSL signal with faster decay due to the temperature dependence of photo-ionization cross-section. To achieve the same decay constant and more signal, the temperature of measurement was raised. As a result of lowering the stimulation in-tensity at higher temperature (85°C) the overall MDD of α-Al2O3:C was found to improve by 1.8 times. For extension of dose linearity in higher range, deeper traps were studied by simultaneous application of CW-OSL and thermal stimulation up to 400°C, using a linear heating rate of 4K/s. By using this method, two well defined peaks at 121°C and 232°C were observed. These TA-OSL peaks have been correlated with two deeper defects which can be thermally bleached at 650°C and 900°C respectively. These deeper defects are stable up to 500°C, so they can store absorbed dose information even if the sample is inadvertently exposed to light or heat. The dose vs. TA-OSL response from deep traps of α-Al2O3:C was found to be linear up to 10 kGy, thus extending its application for high dose dosimetry.