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- Author or Editor: J. Moran x
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Abstract
The transfer of 137Cs and 40K from soil to vegetation was studied in an Atlantic blanket bog ecosystem along the Atlantic coast of Ireland where the dominant vegetation is a mixture of Calluna vulgaris, Eriophorum vaginatum and Sphagnum mosses. The impact of soil chemistry and nutritional status of vegetation on the uptake of both radionuclides was also examined. Cesium-137 transfer factors values ranged from 1.9 to 9.6 and accumulation of 137Cs was higher in the leaves of C. vulgaris than in the stems. Transfer factors values for 137Cs in both C. vulgaris and E. vaginatum were similar indicating that for the vegetation studied, uptake is not dependent on plant species. The uptake of 137Cs in bog vegetation was found to be positively correlated with the nutrient status of vegetation, in particular the secondary nutrients, calcium and magnesium. Potassium-40 transfer factors ranged from 0.9 to 13.8 and uptake was higher in E. vaginatum than in C. vulgaris, however, unlike 137Cs, the concentrations of 40K within the leaves and stems of C. vulgaris were similar. The concentration of both 137Cs and 40K found in moss samples were in general lower than those found in vascular plants.
Summary
The role of organic soil as a sink for radioactive contaminants in a High Arctic environment was studied. Samples were obtained from an area of organic soil located on the Arctic archipelago of Svalbard (79° N) and from a non-organic control site in the same region. Samples were differentiated into organic layers and the underlying material and measured for a suite of anthropogenic and natural radionuclides and for a variety of soil chemistry parameters. Results indicated that the organic components of the soil constitute a sink term for a number of radionuclides. Values for Pu isotopes, 137Cs and 238U were appreciably higher at the study site than at the control site, by up to a factor of 40 for Pu and 20 for 137Cs and 238U. The source of 238U to the site appeared to be enrichment of this isotope from surface or melt water via adsorption to to either iron hydroxides or organic matter although the situation pertaining to Pu and 137Cs remains less clear.
Abstract
The thermal analytical study of most hydrophobic and hydrophilic D/L amino acids reveals significant hydropathy index correlation between the presence of water and crystalline amino acids. The TG derivative mass profiles for arginine and lysine (hydrophilic acids) at various time intervals of atmospheric exposure, show two distinct peaks, one between 50 and 60°C (unbound water), and one close to 100°C (bound-like water). The DSC heat-cool profiles for lysine and arginine confirmed the presence of these multiple waters with two heats of vaporization. The absence of these patterns from the TG and DSC for cysteine and phenylalanine (hydrophobic acids) further supports the conclusions.
The analysis of polymorphic markers within or closely linked to the cystic fibrosis transmembrane regulator (CFTR) gene is useful as a molecular tool for carrier detection of known and unknown mutations. To establish the association between mutations in the CFTR gene in western Mexican cystic fibrosis (CF) patients, the distribution of XV2c/KM19 haplotypes was analyzed by PCR and restriction enzyme digestion in 384 chromosomes from 74 CF patients, their unaffected parents, and normal subjects.The haplotype analysis revealed that haplotype B was present in 71.9% of CF chromosomes compared to 0% of non-CF chromosomes. The F508del and G542X mutations were strongly associated with haplotype B (96.7% and 100% of chromosomes, respectively). The haplotype distribution of the CF chromosomes carrying other CFTR mutations had a more heterogeneous background.Our results show that haplotype B is associated with CFTR mutations. Therefore, haplotype analysis is a suitable alternate strategy for screening CF patients with a heterogeneous clinical picture from populations with a high molecular heterogeneity where carrier detection programs are not available. In addition, it may be a helpful diagnostic tool for genetic counseling and carrier detection in the relatives of CF patients and in couples who are planning to have children.
