Structural, radiation shielding, thermal and dynamic mechanical analysis for waste rubber/EPDM rubber composite loaded with Fe2O3 for green environment.

Increasing waste rubber recycling produces a specious range of products for many valuable applications. Waste Rubber/EPDM composite with different concentrations was prepared. Infrared spectroscopy (FTIR) is used to identify the chemical composition. A water absorption test, Dynamic mechanical analysis (DMA), and Thermal Gravimetric Analysis (TGA) were performed. The (75/25) WR/EPDM rubber composite exhibited the best behavior with the highest mechanical performance. Fe2O3 was added to (75/25) WR/EPDM rubber composite. Water absorption, FTIR, TGA, and DMA were investigated. The composite performance was improved with increasing Fe2O3 content. The linear attenuation coefficients (µ) were also measured as a function of the concentrations of Fe2O3 for γ-ray energy 662 keV by using 137Cs point source; the radiation shielding can be denoted by numbers of parameters like mass attenuation coefficient (µm), half value layer (HVL), Tenth value layer TVL and radiation protection efficiency (RPE%), radiation protection efficiency increased as Fe2O3 increased.

Hepatitis B vaccination in children infected with Schistosoma mansoni: correlation with ultrasonographic data.

Forty-one schoolchildren with positive stools for Schistosoma mansoni eggs and 39 age- and sex-matched children with negative stools were given 3 doses, 5 micrograms each, of a plasma derived hepatitis B vaccine. Their sera were examined 3 and 9 months after the third dose for hepatitis B surface antibody (anti-HBs). At 9 months after vaccination, both the number of responders and the mean of antibody titers were significantly higher in the control group than in the group infected with S. mansoni (97% vs. 56% and 334.8 +/- 192.9 vs. 67.7 +/- 74.4 mIU/ml). There was a negative correlation between anti-HBs titers and the long diameter of the spleen as well as between the titers and the long diameter of the spleen and the liver span in the mid-clavicular line (right lobe) taken together. There was also a positive correlation between anti-HBs titers and the diameters of the portal vein. There was no correlation between anti-HBs titers and any of the following 3 parameters: liver span in the mid-clavicular line (right lobe) alone, liver span in the middle line (left lobe) alone, and the degree of thickness of the periportal fibrosis. There was also no correlation between anti-HBs titers and egg counts in the stools. An interpretation of these findings was made in the light of the role of phagocytic activity of the liver and spleen as well as of porta-caval shunts in the immune mechanism.