Tracer phosphorus

There is an optimum concentration of surface-active substances for which a maximum reduction in adhesive force is achieved. This is confirmed by our experimental results for aqueous solutions of OP-10 (Fig. IV.19). On raising the concentration of surface-active substances to 1% adhesion diminishes (curves 2 and 3). Further raising the concentration (above 1%) causes micelle formation and has little effect on adhesion. A similar effect is exerted on the adhesion of particles in an aqueous medium by the complex-forming substance sodium hexametaphosphate (curves 1 and 4). Our experiments based on sodium hexametaphosphate with a tracer phosphorus atom show that, like certain condensed polyphosphates [197] this substance may collect on the surface of the contiguous bodies and thus facilitate the detachment of particles. 

Phosphorus has only one stable isotope, J P, and accordingly (p. 17) its atomic weight is known with extreme accuracy, 30.973 762(4). Sixteen radioactive isotopes are known, of which P is by far the most important il is made on the multikilogram scale by the neutron irradiation of S(n,p) or P(n,y) in a nuclear reactor, and is a pure -emitter of half life 14.26 days, 1.7()9MeV, rntan 0.69MeV. It finds extensive use in tracer and mechanistic studies. The stable isotope has a nuclear spin quantum number of and this is much used in nmr spectroscopy. Chemical shifts and coupling constants can both be used diagnostically to determine structural information. 

Tracer techniques are used widely in biology. Botanists, for example, work to develop new plant hybrids that grow more rapidiy. One common way to determine how fast plants grow is to measure how quickly they take up elemental phosphorus from the soil. New hybrids can be planted in a plot and fertilized with phosphoras enriched 32 32... 

Radioactive isotopes provide a very convenient way of monitoring the fate or metabolism of compounds that contain the isotopes. When used in this way, the isotope is described as a tracer and compounds into which the radioactive atom has been introduced are said to be labelled or tagged. The labelled molecules need only comprise a very small proportion of the total amount of the unlabelled radioactive substance because they act in the same way as the non-radioactive substance but can be detected very much more easily. The varied applications of tracers in biochemistry range from studies of metabolism in whole animals or isolated organs to sensitive quantitative analytical techniques, such as radioimmunoassay. Phosphorus-32 is used in work with nucleic acids, particularly in DNA sequencing and hybridization techniques. In these instances the isotope is used as a means of visualizing DNA separations by autoradiographic techniques. 

Fig 1-13 120-mm WP-T (WHITE PHOSPHORUS-TRACER) SMOKE PROJECTILE M357 (T16E4)... 

Typical Burster-Type Smoke Artillery Projectile, such as 120-mm WP-T (White Phosphorus-Tracer) Smoke Projectile M557 (TI6E4) (Burster Type), shown in Fig 1-13, belongs to the type of chemical projectiles. It consists of a hollow, forged steel body filled with 7.2 lb of WP and fitted with PD fuze. There is a boss on the base of proj contg a tracer. 

Fuze, BD M534A1 has been used with WP-T (White phosphorus with tracer) cartridge M416 in 105-mm cannon M68. Its description is given in Ref 52, p 5-107, but there is no drawing... 

Phosphorus-32, for example, produced by irradiating sulphur or natural phosphorus ( P) with high-energy particles, has a half-life of 14.8 days and can be rapidly taken up (in the form of phosphate) by body tissues such as muscles, the liver, bones, and teeth. De Hevesy found that different phosphorus compounds would be incorporated in a tissue-specific manner certain compounds were concentrated in the liver, for example. One can use stable isotopes as biological tracers too, since they are detectable atom by atom using mass spectrometry. De Hevesy observed that it takes deuterium twenty-six minutes to pass from ingested heavy water into urine. 

Imboden, D. M., and S. Emerson, Natural radon and phosphorus as limnological tracers Horizontal and vertical eddy diffusion in Greifensee , Limnol. Oceanogr., 23,77-90 (1978). 

When 31P is bonded to lsO the chemical shift of the 31P is altered by 0.0206 ppm from that when the phosphorus is bonded to leO. This allows lsO labels introduced into phospho groups to serve as tracers which can be followed continuously during reactions.683 The technique is useful in studies of stereochemistry (see Section 2) and for examination of positional isotope exchange.690 This latter technique is often used with ATP containing lsO in the P,y-bridge position. If an enzyme transfers the terminal (y) phospho group to an acceptor via a phosphoenzyme but without loss of the ADP, we may expect positional isomerization. The lsO will move between the P,y-bridge position and... 

Nucleotides - [AMINO AC IDS - L-MONOSODIUM GLUTAMATE (MSG)] (Vol 2) -as antibiotics [ANTIBIOTICS - NUCLEOSIDES AND NUCLEOTIDES] (Vol 3) -catabolism of [MINERALNUTRIENTS] (Vol 16) -electrodes for [BIOPOLYMERS - ANALYTICAL TECHNIQUES] (Vol 4) -phosphorus nmr [MAGNETIC SPIN RESONANCE] (Vol 15) -as radioactive tracers [RADIOACTIVETRACERS] (Vol 20)... 

Incubation of lake water with 32P or 33P as tracers and subsequent gel chromatography reveals that a major pathway exists between dissolved orthophosphate and the particulate phase (3, 5-7). Low-molecular-weight phosphorus forms in the presence of bacteria and algae. SUP is present in the low-molecular-weight fraction and is classified as individual DOP compounds unassociated with particulate or colloidal material. The HMW fraction found in gel chromatography studies is characterized as a colloid that contains phosphorus compounds or incorporates orthophosphate. The colloidal material then releases orthophosphate, replenishing the dissolved phosphorus cycle. In some eutrophic lakes the HMW SRP fraction can make... 

HEVESY, GEORG de (1885-1966). A Hungarian chemist who won the Nobel prize in chemistry in 1943, for his work on (he use of isotopes as tracers in the study of chemical processes. He discovered the element hafnium in 192.7. One of his interesting projects involved the calculation of ihc percentages of chemical elements in the universe. He also was involved in research using radioactive lead and phosphorus traces. His work included the separation of isotopes by physical means. His Ph D was granted ai Freiburg in 1908. 

The extraction of U(VI), at tracer concentrations, from dilute acid solutions, by dialkyl phosphorus acids, have been suggested to take place by four kinds of equilibria, by different authors. These are... 

Several zinc absorption studies, using oral doses of ZnCl2 were carried out. 65zq plasma levels were determined serially on the day of the oral administration of the zn tracer. Urinary and fecal 65zn excretions were determined for approximately 15 days. The subjects studied were fully ambulatory males who were In good nutritional state. They were normal according to all clinical and laboratory criteria. Including the serum levels of zinc, calcium, and phosphorus. The effect of three Intake levels of calcium on the zinc balance was studied, namely, of 200, 900,... 

Several studies have examined unconcentrated bulk water using a tracer approach. Goering et al. (1966) first reported on unconcentrated, bulk water uptake studies off the northeast coast of South America. Their results could account for rates of about 86 and 271 pmol N2 m day for 2 observations and 9 observations in the fall of 1966 and spring of 1967, respectively. They reported appreciable Trichodesmium in most of their samples. Voss et al. (2004) recendy found relatively high rates on the eastern side of the basin off NW Africa, with somewhat lower rates on the western boundary, and activity was below detection Emits in the central portion of the basin (Tables 4.4 and 4.5). Rees et al. (2006) observed very high rates of N2 fixation in the eastern Mediterranean which were apparently limited by phosphorus availability (Table 4.4). 

In May 1938, Sam received the degree of Doctor of Philosophy in Chemistry. The title of his doctoral dissertation is Studies in Artificial Radioactivity. It has three sections (i) One involves fimdamental physics of iodine and neutrons, (ii) The second section concerned chemical reaction rates using radioactive iron, (iii) The third and longest section used radioactive tracers to study a fundamental problem in biology. It involved stomach-feeding radioactive phosphorus to rats, and after an elapsed period of time he killed the rats to determine which organs of the body had taken up the radioactivity. Ruben published six articles from his thesis research. 

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