Water transport radioactive methods

Quantitative measurement of diffusional uptake and carrier-mediated transport of nutrients and drugs in experimental animals was greatly facilitated with the introduction of Olden dorfs brain uptake index (BUI) [42].Test and reference tracers are injected as an intraarterial bolus into the carotid artery of the anaesthetized animal. After 5 s the animal is killed and the brain is removed for radioactivity counting. This method measures the ratio of the unidirectional brain extraction, E, of the test substance and of the reference ([ H]-water, [ " C]-butanol), which are labelled with different isotopes, during a single passage through the brain capillary bed ... 

Most research work on the use of supercritical water has been conducted batchwise and involved non-analytical determinative applications. Thus, supercritical water oxidation (SCWO) was proposed as an alternative treatment for hazardous waste disposal [191] and also as a commercial tool for decomposing trichloroethylene, dimethyl sulphoxide and isopropyl alcohol on a pilot plant scale [192]. Current commercially available equipment (the aqua Critox" system) is usable with industrial and municipal sludge, mixed (radioactive and organic, liquid and solid) waste and military waste. This commercially available treatment has a number of advantages, namely (a) because it uses an on-site treatment method, it avoids the need to transport hazardous materials (b) it ensures complete destruction of organic wastes and allows reuse of the effluent as process water with results that meet the regulations for drinking water and (c) no licence for effluent or air emissions is needed. 

There are also several methods to determine patterns of fate and transport of pollutants in the environment. In some cases, microcosms and me-socosms are used to study fate, biodegradability, bioavailability, and transport within compartments. Field surveys may also be used to study fate and transport of pollutants in contaminated environments. Such studies involve collection and analysis of biota, water, air, soil, or sediment. In some cases, radioactively labeled contaminants ( tracers ) may be introduced in mesocosms or noncontaminated environments in order to determine their fate and patterns of transport. Finally, mathematical models are often used to produce computer simulations to... 

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