The long-lived radionuclide Tc-99 is thought to be highly mobile in biogeochemical cycles, however, the behavior in the natural environment is not clear because Tc is a redox sensitive element. Since the geochemical behaviors of Re and Tc are similar, Re transfer factors from soil to plant can be a Tc surrogate in the natural environment. However, in soil solution to plant systems, it was not c...

Total dissolved inorganic carbon (SigmaCO(2)) and aqueous carbon dioxide (H(2)CO(3) (*)) in nutrient solutions may be measured by the injection of small gas or liquid samples (1 microliter to 8 milliliters) into a gas stripping column connected in-line with an infrared gas analyzer. The measurement of SigmaCO(2) in solution requires sample acidification, while H(2)CO(3) (*) and gaseous CO(2) ar...

The effects of 10, 20, 35 and 50 mg of Ca(2+) per liter on the qualitative and quantitative exudation of sugars from roots of 5-week-old peanut plants, Arachis hypogaea L., grown axenically in nutrient solutions, were measured. Nutrient solutions in which plants had been growing were collected at weekly intervals for 4 weeks, sugars in them were measured by gasliquid chromatography of the trime...

Earlier this year, we reported on the contamination of a closed enteral feeding system (Isocal) 1 where Gramnegative bacilli were recovered from nutrient solutions obtained from the feeding tubes of 8/10 patients, within 24 hours of use. Our findings differed from those of laboratory studies carried out by others2 which indicated that solutions delivered by the same enteral feeding system remai...

A bstract. Increasing concentrations of K (20, 200, 2000 ,uM) in the nutrient solution depressed Ca content and concentration in barley plants growing in nutrient solutions of low Ca concentrations (250 and 2500 Mm). Increasing K from 20 to 200 AM depressed Ca absorption more than increasing K from 200 to 2000 FM K. The strong depression of Ca absorption by low concentraltions of K must involve...

The removal of nutrients (nitrogen (N), phosphorous (P)) from waste water has become a resource recovery option in recent regulations worldwide, as observed in the European Union. Although both of these nutrients could be recovered from the sludge line, >70-75% of the N and P is discharged into the water line. Efforts to improve the nutrient recovery ratios have focused on developing low-cost t...

Although pure cultures of algae, in nutrient solution, have been used extensively in research on photosynthesis, the excretion of products into the medium has not been reported, despite their possible importance in the physiology and biochemistry of such cultures. The present investigation with the Cl4 tracer has revealed a significant, and apparently functional, secretion of glycolic acid by C...