The ion exchange of Na for Cr/K, Cr/Mg and Cr/Ca in Y and X zeolites was studied using breakthrough curves. It was observed that Cr ions were able to remove some competitive ions that had already been exchanged at the zeolitic sites, producing a sequential ion exchange. Some mass transfer parameters such as length of unused bed, overall mass transfer coefficient, operational ratio and dimension...

OBJECTIVE To examine whether long-term measures of cortisol predict Alzheimer disease (AD) risk. METHOD We used a prospective longitudinal design to examine whether cortisol dysregulation was related to AD risk. Participants were from the Baltimore Longitudinal Study of Aging (BLSA) and submitted multiple 24-hour urine samples over an average interval of 10.56 years. Urinary free cortisol (UF...

Induction of DNA damage by carcinogenic hexavalent chromium compounds [Cr(VI)] results from its reduction to lower oxidation states. Reductive metabolism of Cr(VI) generates intermediate Cr(V/IV)species, organic radicals, and finally Cr(III), which forms stable complexes with many biological ligands, including DNA. To determine the biological significance of different reaction products, we exam...

background: due to difficulty of obtaining a 24h urine (especially in children), a random urine calcium sample is recommended to detect of hypercalciuria. however, recent studies have shown that the urinary calcium/creatinine ratio varies with age and geographic areas. so, the aim of this study was determining the normal value of urinary calcium to creatinine ratio in healthy adolescent’s child...

To investigate the role mitochondrial membrane lipids play in the actions of CR (calorie restriction), C57BL/6 mice were assigned to four groups (control and three 40% CR groups) and the CR groups were fed diets containing soya bean oil (also in the control diet), fish oil or lard. The fatty acid composition of the major mitochondrial phospholipid classes, proton leak and H(2)O(2) production we...