Isotopes iodine

Iodine [7553-56-2] I, atomic number 53, atomic weight 126.9044, is a nonmetaUic element belonging to the halogen family in Group 17 (VIIA) of the Periodic Table. The only stable isotope has a mass number of 127. There are 22 other iodine isotopes having masses between 117 and 139 14 of these isotopes yield significant radiation. 

The Zag meteorite fell in the western Sahara of Morocco in August 1998. This meteorite was unusual in that it contained small crystals of halite (table salt), which experts believe formed by the evaporation of brine (salt water). It is one of the few indications that liquid water, which is essential for the development of life, may have existed in the early solar system. The halite crystals in the meteorite had a remarkably high abundance of 128Xe, a decay product of a short-lived iodine isotope that has long been absent from the solar system. Scientists believe that the iodine existed when the halite crystals formed. The xenon formed when this iodine decayed. For this reason, the Zag meteorite is believed to be one of the oldest artifacts in the solar system. In this lab, you will use potassium-argon radiochemical dating to estimate the age of the Zag meteorite and the solar system. 

These are used invariably for the gamma-energy emitting isotopes, for instance 125I-the more common iodine-isotope. 

Because the interactions measured in Mossbauer experiments are products of atomic and nuclear factors, experiments on iodine isotopes have yielded values of the change of nuclear radius between the ground state and the excited state, AR/R, quadrupole moment values Q, and magnetic moment values, fi, as well as electric field gradients and internal magnetic fields. 

Magnetic Hyperfine Structure. The magnetic fields in most magnetic iodine and tellurium compounds are not sufficient to separate the 18 magnetic hyperfine lines of the two iodine isotopes. Several measurements (13, 21, 34, 36) have indicated that fields of only about 100 kilo-gauss can be expected from such compounds. Therefore, other methods must be utilized. 

As indicator enzymes horseradish peroxidase (HRP or HRPO), alkaline phosphatase (AP), or /i-galactosidase, are favored, since they are relatively robust, have a high product-forming rate, are easy to purify, and are cheap. The most used colloids are from gold, silver, and iron, and iodine isotopes are mostly taken as radioactive labels in immunoassays. 

Making metastable technetium-99 is an expensive business. A cheaper, common alternative tracer is iodine-131, which emits a gamma ray when it decays. But the iodine isotope also releases beta particles that can damage tissues, making it less attractive as an imaging agent. 

Radioactive labels are -emitters selected on the basis of half-lives, the energies emitted, decay products, ease of labeling, availability and expense. Iodine isotopes 121,123, and 124, Indium 111, and Technetium 99 are the labels most widely used. The short half-lives of these labels (hours to days) means that radioimaging reagents are prepared immediately prior to treatment. Radioimaging of diseased tissue also provides useful information on the design of therapies that localize radioisotopes or toxins at tumor sites for therapy. 

Thus, there were serotonin 1 receptors, and then there were 1 and 2 receptors, and then la and lb and 2a and 2b receptors, and on and on. These are called 5-HT receptors, since the chemical name for serotonin is 5-hy-droxytryptamine, and the scientist would never want to let the layman know just what he is talking about. DOI has been synthesized with a variety of radioactive iodine isotopes in it, and these tools have been of considerable value in mapping out its brain distribution. And by extrapolation, the possible localization of other psychedelic compounds that cannot be so easily labelled. A small neurochemical research company on the East Coast picked up on these properties of DOI, and offered it as a commercial item for research experiments. But I doubt that they are completely innocent of the fact that DOI is an extremely potent psychedelic and that it is still unrecognized by the Federal drug laws since, in their most recent catalog, the price had almost doubled and a note had been added to the effect that telephone orders cannot be accepted for this compound. 

Accidents with nuclear reactors or nuclear bombs can expose large numbers of people to several decay products of uranium, and iodine isotopes are among the most abundant compounds released in such reactions. It is therefore logical to use salts of stable isotopes of iodine to prevent the accumulation of radioiodine in a person or population at risk of such exposure. The accidents in Windscale (UK), Three Mile Island (USA), and particularly Chernobyl (Ukraine) drew attention to such problems. The major question is therefore whether the potential adverse effects of stable iodine when given indiscriminately to large... 

Snyder GT, Fehn U, Goff F (2002) Iodine Isotope Ratios and Halide Concentrations in Fluids of the Satsuma-Iwojima Volcano, Japan. Earth Planet Space 54 265... 

A brief survey is given of the technique and its limiting parameters. Recent results on moments of proton rich iodine isotopes show shape coexistence and the presence of the gg/2 [404] intruder orbital for A > 118. 

Following near-ground explosions, iodine isotopes are concentrated in the smaller particles, but H-tests at high altitude produce very small particles, which equilibrate with other aerosols in the stratosphere, and there is little fractionation. After the Chinese test of 15.10.80, high... 

The transfer factor Fm from feed to milk is defined in equation (2.11) as the activity per litre expressed as a fraction of the activity ingested daily by the cow. Numerous measurements of Fm have been made by dosing cows with iodine isotopes or by comparing radioactive or stable iodine in milk and in the herbage eaten by the cows. Table 3.6 shows a selection of the results. Fm depends on the yield of milk and on seasonal factors (Gamer, 1971), but it does not appear to depend on the chemical form of the iodine (Bretthauer et al., 1972). Gamer (1971) recommended Fm = 5 x 10 3 d l-1 for UK conditions, but noted that US results tended towards a higher value. 

Knapp calculated that Cfonax) would have been in the range 0.7-2.6 [xd 1 1(0.026-0.10 MBq l-1) at St George, a range of values which is consistent with measurements near Windscale (Dunster et al., 1958 Booker, 1958). Knapp calculated further that an infant drinking 11 of milk per day (perhaps more than is usual) would have received a thyroid dose of 120-440 rad (1.2-4.4 Gy). Since the iodine isotopes are (3, y emitters, the dose equivalent in Sv is the same as the dose in Gy. 

Mossbauer spectroscopy with the iodine isotopes is not a practical method for identification or quantification of organic compounds (nor of inorganics). It is most applicable for discerning electronic effects and charge states. For these applications, 129I gives far better results, and allows the separation of superposed subspectra. It is unfortunate that its use requires radiochemical techniques and very small scales. 

Admissible condition means the presence of microcracks in claddings through which gaseous and volatile fission products (noble gases, iodine isotopes) are released to coolant. 

Fall of container with spent nuclear fuel Assembly destruction with cumulative activity escape of gas products and iodine isotopes. 

I has been applied recently in medicine where it causes lower radiation injury to the organism compared to the other iodine isotopes. 

Radioisotopes of the halogens have found uses in studies of exchange reactions and reaction mechanisms. A radioactive iodine isotope is used in medical diagnostics. 

The specific activity of proteins assayed by direct immunochemical methods or those used as standards in radioimmunoassays profoundly affects the resolution attainable by these techniques. Therefore, the nature of the radioactive label to be used in such experiments must be considered carefully. Table 8-6 lists the isotopes available for this purpose along with the number of atoms of each isotope that must be incorporated to produce an arbitrary counting rate. As can be seen here, 557 atoms of H and 261,672 atoms of C must be incorporated into every molecule of protein to yield the same number of disintegrations per minute as only one I or 11 S molecules. S-methionine is often the isotope of choice for many direct immunochemical procedures since it is relatively inexpensive to prepare at high specific activity. On the other hand, the relative ease with which radioactive iodine may be incorporated into a purified antigen makes it the isotope of choice for radioimmunoassay methods. Of the two iodine isotopes available, is most often used because of its longer half-life. This is an important consideration since it usually takes more than 1 week to prepare and test a labeled antigen prior to its experimental use. 

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