Distribution and ratios of 137Cs and K in control and K-treated coconut trees at Bikini Island where nuclear test fallout occurred: effects and implications.

Coconut trees growing on atolls of the Bikini Islands are on the margin of K deficiency because the concentration of exchangeable K in coral soil is very low, ranging from only 20 to 80mgkg(-1). When provided with additional K, coconut trees absorb large quantities of K and this uptake of K significantly alters the patterns of distribution of 137Cs within the plant. Following a single K fertilization event, mean total K in trunks of K-treated trees is 5.

(137)Cs inter-plant concentration ratios provide a predictive tool for coral atolls with distinct benefits over transfer factors.

Inter-plant concentration ratios (IPCR) [Bqg(-1)(137)Cs in coral atoll tree food crops/Bqg(-1)(137)Cs in leaves of native plant species whose roots share a common soil volume] can replace transfer factors (TF) to predict (137)Cs concentration in tree food crops in a contaminated area with an aged source term. The IPCR strategy has significant benefits relative to TF strategy for such purposes in the atoll ecosystem. IPCR strategy applied to specific assessments takes advantage of the fact that tree roots naturally integrate (137)Cs over large volumes of soil.

Long-term reduction in (137)Cs concentration in food crops on coral atolls resulting from potassium treatment.

Bikini Island was contaminated on March 1, 1954 by the Bravo detonation (U.S. nuclear test series, Castle) at Bikini Atoll.

Dental caries in young male adults: prevalence, severity and associated factors.

The aim of the present study was to determine the prevalence and severity of dental caries as well as the needs for dental treatment in 18-year-old males from Maringá, PR, Brazil. The association of dental caries experience with socioeconomic variables was also tested. A cross sectional study was conducted in a random sample of 241 conscripts of the Brazilian Army.

Remineralization of carious dentin. II: In vivo microradiographic and chemical studies in human permanent teeth capped with calcium hydroxide.

The main aim of this in vivo study was to evaluate a possible remineralization of human carious dentin by means of chemical and microradiographic studies. Eighty-six samples of carious dentin were removed from 36 permanent teeth of 24 patients. These were divided into untreated (control) and chemically pure calcium hydroxide-capped (experimental) samples and analyzed at intervals varying from 10 to 120 days.