Search

The Radium Delayed Coincidence Counter (RaDeCC) is one of the most extensively used equipment for measuring 223Ra and 224Ra activities in water and sediment samples. Samples are placed in a closed He‐circulation system that carries the Rn produced by the decay of Ra to a scintillation cell. Each alpha decay recorded in the cell is routed to an electronic delayed coincidence system which enables the discrimination of 223Ra and 224Ra. In this study, the measurement and quantification methods using the RaDeCC system are assessed through analyses of registered data in different RaDeCC systems worldwide and a set of simulations. Results of this work indicate that the equations used to correct for 223Ra and 224Ra cross‐talk interferences are only valid for a given range of activities and ratios between isotopes. Above certain limits that are specified in this study, these corrections may significantly overestimate the quantification of 223Ra and 224Ra activities (up to ~40% and 30%, respectively), as well as the quantification of their parents 227Ac and 228Th. High activities of 226Ra may also produce an overestimation of 224Ra activities due to the buildup of 222Rn, especially when long measurements with low activities of 224Ra are performed. An improved method to quantify 226Ra activities from the buildup of 222Rn with the RaDeCC system is also developed in this study. Wethus provide a new set of guidelines for the appropriate quantification of 223Ra, 224Ra, 227Ac, 228Th, and 226Ra with the RaDeCC system. Plain Language Summary: In the last decades, there has been a growing interest in using radioactive isotopes to evaluate environmental processes. Their concentrations in environmental settings can reveal information about provenance, path, time, and duration. In this scenario, the research in the techniques to measure isotopes from samples has played a key role. In 1996, the launching of the Radium Delayed Coincidence Counter (RaDeCC) facilitated the fast and precise measurement of Ra isotopes, which provide information on land‐ocean interaction processes (e.g., groundwater discharge to the sea and coastal residence times). Nowadays, this detector has become a fundamental tool for oceanographers, geochemist, and hydrologist among other scientific communities. Nevertheless, when the RaDeCC system was released, its quantification limits were not provided, and the recommendations on its use were mostly qualitative. More than 20 years later, we address these questions in a study that contains a comprehensive analysis of the RaDeCC counting mechanism and the determination of the limits of quantification. This study should serve as guidance for the measurement and quantification of Radium isotopes for the scientific community using the RaDeCC system. Key Points: The maximum quantification limits for 223Ra and 224Ra are 200 and 100 cpm in the total channel, respectivelyLimits for the quantification of 223Ra and 224Ra are provided when measurements are influenced by cross‐talk and 222Rn buildup effectThe understanding of RaDeCC counting systematics derived from simulations allowed improving the quantification of 226Ra via 222Rn buildup [ABSTRACT FROM AUTHOR]

Objective It was hypothesized that binge eating (bulimia nervosa [BN]) may be caused by the anticipatory and immediate anxiety associated with certain types of food. Consequently, an extinction schedule should reduce binge eating. Methods Cue exposure was carried out with 6 bulimic women who had responded poorly or not at all to the usual pharmacologic or cognitive-behavioral treatments. Results Binge eating and vomiting were almost totally suppressed in the 6 patients. Symptom suppression was maintained at two follow-ups, one at 4–20 months and another at 2.5–3 years. Discussion Cue exposure may be effective with BN that is resistant to conventional treatments. The anxiety associated with food plays an important role in provoking and/or maintaining binge eating. Motivation to change is likely to be an important mediator. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 34: 227–234, 2003. [ABSTRACT FROM AUTHOR]

It was demonstrated the critical role of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) on the development of cardiac disorders. Diet rich in fruits and vegetables are related to a diminish risk of chronic disease due to oxidative stress for their content in phytochemicals Onions (Allium cepa L.) have bioactive compounds including polyphenols and sulphur-compounds that are antioxidants and positive inducers of phase II detoxifying enzimes; they protect cells from oxidative damage. We study the effects of onion juice consumption on lipid and protein oxidation of cardiac muscle of Wistar rats. Polyphenolic composition of onion that was administrated to experimental animals was determined by HPLC. Diet consumption and onion supplement at two level doses (D1 and D2 groups), growth curves of animals and the oxidative state of lipids and proteins of cardiac muscles were also determined. Control group fed only experimental diet(C group).No significant differences, for diet consumption and growth curves, were observed when D1 and D2 were compared with C.Onion supplement consumption was statistically different between D1 (0.671g/day) and D2 (1.775 g/day). Protective effect was observed in D1 cardiac proteins (D1= 4.36 ± 0.95; D2 = 5.24 ± 0.87; C=6.43 ± 0.75 nmol carboniles/mg prot, p<0.0088)and a higher lipid oxidation in D2 (D1=1.82 ± 0.27; D2=2.51 ± 0.33; C=1.59 ± 0.19 µg MDA/gr tissue, p<0.0004). It was observed that the antioxidant/pro-oxidant response was quantity- dependent and showed differential effects for both macromolecules. [ABSTRACT FROM AUTHOR]