Radioisotopes tracers

Thin layer activation (TLA) has a long experience in monitoring or measuring wear and erosion. A small quantity of radioisotope tracer is introduced into the metal surface which can be either a coupon or component. Metal loss due to corrosion (provided the corrosion product is non-adherent) can be detected remotely with high sensitivity . 

Santschi PH, Guo LD, Asbill S, Allison M, Kepple AB, Wen LS (2001) Accumulation rates and sources of sediments and organic carbon on the Palos Verdes shelf based on radioisotopic tracers ( Cs, " °Pu, 240pu, 2i0pb, 234xh, 238u j d C). Marine Chem 73 125-152 Sarin MM, Church TM (1994) Behavior of uranium during mixing in the Delaware and Chesapeake Estuaries. Estuar Coastal Shelf Sci 39 619-631... 

Chromiums most important radioisotope is chromium-51, which has a half-life of about 27 days. It is used as a radioisotope tracer to check the rate of blood fiowing in constricted arteries. 

It has limited use in medicine as a radioactive source. It concentrates in the thyroid gland just like iodine, which makes it a useful radioisotope tracer. 

Jl. Jackson, T. M., and Ekins, R. R, Theoretical limitations on immunoassay sensitivity. Current practice and potential advantages of fluorescent Eu + chelates as non-radioisotopic tracers. J. Immunol Methods 87, 13-20 (1986). 

Jackson (Jl), 1955 Flow of films of ethyl acetate, methanol, water, water + surfactant, 2-propanol, glycerol solutions (with and without surfactant), inside tube of 3.6 cm. diameter. Film thicknesses by radioisotope tracer method heights of waves measured. Surface tension had little effect. 

Radiophannaceuticals are almost ideal diagnostic tools because radioisotope tracers do not alter body physiology, and they permit external monitoring with minimal instrumentation. Presently, there are three major areas of nuclear medicine (1) physiological function studies, (2) radionuclide imaging procedures, and (3) therapeutic techniques. 

Source Radioisotope Tracers in Industry and Geophysics. Vienna International Atomic Energy Agency, 1967. 

Toxicokinetic data for aluminum have been somewhat limited by a paucity of radioisotope tracer experiments, which have only recently been conducted with aluminum due to the lack of a suitable and convenient radioisotope. 28A1 can be produced, but it has a half-life of only 2.3 minutes (Ganrot 1986). Recently, 26A1 (half-life 7.2xl05 years) has been produced by accelerator mass spectrometry. Although 26A1 is not widely available to researchers, it has been used in a number of human and animal studies to... 

D2. Deacon, A. L., Hulme, P., Hesp, R., Green, J. R., Teller, M., and Reeve, J., Estimation of whole body bone resorption rate A comparison of urinary total hydroxyproline excretion with two radioisotopic tracer methods in osteoporosis. Clin. Chim. Acta 166, 297-306... 

Cation exchange can be conveniently studied by radioisotopic tracer methods because of the fairly broad concentration range that can be used, from tracer (carrier-free isotopes) to high (applying an inactive carrier) concentrations. 

The basic information in the study of sorption processes is the quantity of substances on the interfaces. In order to measure the sorbed quantity accurately, very sensitive analytical methods have to be applied because the typical amount of particles (atoms, ions, and molecules) on the interfaces is about I0-5 mol/m2. In the case of monolayer sorption, the sorbed quantity is within this range. As the sorbed quantity is defined as the difference between quantities of a given substance in the solution and/or in the solid before and after sorption processes (surface excess concentration, Chapter 1, Section 1.3.1), all methods suitable for the analysis of solid and liquid phases can be applied here, too. These methods have been discussed in Sections 4.1 and 4.2. In addition, radioisotopic tracer method can also be applied for the accurate measurement of the sorbed quantities. On the basis of the radiation properties of the available isotopes, gamma and beta spectroscopy can be used as an analytical method. Alpha spectroscopy may also be used, if needed however, it necessitates more complicated techniques and sample preparation due to the significant absorption of alpha radiation. The sensitivity of radioisotopic labeling depends on the half-life of the isotopes. With isotopes having medium half-time (days-years), 10 14-10-10 mol can be measured easily. 

Interest In mineral-mineral Interactions emerged In the 1960s. Most early experiments In laboratory animals Involved either radioisotopic tracers or manipulation of the dietary ratios between and among minerals. In the latter feeding experiments, the exacerbation of manifestations of deficiency of one mineral (M by excess amounts of a second (M2), or the amelioration of the clinical signs of M2 toxicity by Increasing the dietary levels of... 

When this reaction is carried out with CH3OH containing radioactive oxygen-18, the water produced does not contain oxygen-18. Explain the results of this radioisotope tracer experiment. 

The analytical procedures presented in this study are relatively simple and sample through-put through the mass spectrometer is reasonable (15 min per replicate). The results indicate that the method has promise as an alternative to radioisotope tracer methods. Long-term studies and studies with infants, children, and women are feasible without hazards to the subjects. 

The direct radioisotope tracer method, in which the accumulation of radiolabeled product from added radiolabeled substrate over time yields a rate estimate, is not very practical for measuring rates of nitrification in the environment. Capone et al. (1990) were able to quantify nitrification rates using but the isotope is so shortlived (10 min half-life) that its use is usually impractical. 

This method is commonly used with radioisotope tracers that undergo radioactive decay. The tracer concentration will decrease over time following an exponential decay law ... 

The main areas where radioisotope tracers may be used are ... 

In the processing industries, one of the major applications of radioisotope tracers is for residence time investigations in which important parameters for plant optimisation, modelling, and automation are obtained. 

The study of wear on machine parts, which were labelled by radioisotopes, is an important stage in the development work of the automotive industry. The design of a new motor necessitates hundreds of wear tests to be carried out. These tests can be made by using the radioisotope tracer technique. The surface activation technique, in... 

Immediately before turning off the current, 1 ml of concentrated NH OH is added to the cell and the electro-deposition continued for an additional minute. The current is then turned off, the solution discarded, and the electrode washed with water, then ethanol and air-dried. Following alpha energy analysis, the radiochemical yield, as determined from the radioisotope tracer content and the concentrations of the radionuclides of interest, are calculated. 

For the case of radioisotope tracer experiments, nonintrusive methods are used to get the outlet concentration of tracer by utilizing collimated scintillation detectors. Radioisotope tracers have many advantages such as on-line detection, high detection sensibility, and availability in different compatible forms over conventional tracers.This method can also help in troubleshooting and checking the performance of industrial TBR under operational conditions. 

Radioisotopes used as tracers solve scientific mysteries Radioactive and nonradioactive isotopes of the same element act the same way in a chemical reaction. When scientists want to put tags on a compound, they substitute a radioactive isotope for a nonradioactive one in the compound. Then they can use radiation detectors to track and locate the radioisotope tracer. 

There have been very few measurements of bone formation rate in primary hyperparathyroidism. Bone turnover determined by the stable strontium test of Fraser et al. (FIO) is reported to be high in cases of parathyroid tumor, but it is not known whether this is true of radioisotopic tracer tests. 

Radioisotopic tracers emit nonionizing radiation and have been used to study reaction mechanisms, material flow, elemental composition, and medical conditions. Ionizing radiation has been used to destroy cancerous tissue, kill organisms that spoil food, and control insect populations. 

Nuclear radiation absorption methods have many technical applications. These methods are not to be confused with radioisotope tracer methods, although radioisotopes may be used as radiation sources. In the tracer method the chemical properties of the radionuclide are important while in the applications discussed in this section only the type and energy of radiation emitted are irqx>rtant. 

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