Amounts Of Radioactive Isotopes Research Articles

Radon Assessment in Ceratophyllum demersum Plant Samples

The amount of radioactive isotopes in submerged Ceratophyllum demersum plants samples were estimated using passive track detector CR-39. The samples were collected from four selected sites along the Tigris River in Baghdad city, on a monthly basis for one complete year of 2019. Certain factors like radon concentration (Bq.m-3), radium content (Bq.kg-1) and uranium concentration (ppm) were evaluated. The average values of 222Rn level, 226Ra content and 238U concentration in Ceratophyllum demersum samples for site (1) were (593.1 Bq.m-3, 5.8 Bq.kg-1, 0.113 ppm), site (2) were (413.4 Bq.m-3, 3.8 Bq.kg-1, 0.074 ppm), Site (3) were (465.5 Bq.m-3, 4.3 Bq.kg-1, 0.083 ppm) and site (4) were (431.3 Bq.m-3, 3.9 Bq.kg-1, 0.077 ppm), respectively. The results obtained in this work indicated that the radium content and uranium concentration present in the Ceratophyllum demrsum is acceptable which does not pose any risk to the aquatic ecosystem.

Fukushima Nuclear Power Plant accident: Various issues with iodine distribution and medication orders.

Immediately after the Great East Japan Earthquake on March 11, 2011, the public could not receive accurate information concerning about the reality of the accident at the Fukushima Nuclear Power Plant because of communication problems with mobile phone base stations caused by power outages and the inadequate use of communication satellites between local governments. These telecommunications troubles caused not only a delay between the Japanese central government to local governments, but also a failure in conveying the seriousness of the accident to residents. The central government issued evacuation orders, but in some areas, a delay was seen in the time residents took to notice the orders. Some residents were forced to change their evacuation site several times and move to areas with higher radiation exposure. Although iodine preparations needed to be distributed to saturate the thyroid gland and reduce the uptake of iodine-131, a radioactive isotope, many municipalities were unable to secure them. Preparations were distributed on March 15, 2011 when the detectable amount of radioactive isotopes peaked, but only the Naraha and Miharu towns received them. At the time of the Fukushima Nuclear Power Plant accident, communication lines had already been interrupted by the major earthquake that struck on March 11, and information systems between local governments were not communicating well. With such a social infrastructure, residential evacuation orders were inadequate, and the delivery of medication was extremely difficult. The experience of the Fukushima Nuclear Power Plant accident suggests that the government should have distributed iodine preparations to residents living within a 30-km radius of the plant in advance, so that they could learn about the background and side effects of the drug beforehand. This distribution strategy is similar to that of targeted antivirus prophylaxis (TAP), which is an extralegal policy carried out in situations where face-to-face medical treatment is impossible because of an outbreak during a pandemic.

Silica Nanoparticles Containing Gadolinium Complex as Potential Alternative to Anticancer Radiotherapy

Today, cancer represents one of the main causes of death worldwide, making it a formidable challenge for all scientific areas that seek new therapeutic approaches for its cure. As a therapeutic approach, radiotherapy, widely used in treating various types of tumors, acts by not discriminating healthy cells from tumor cells. Seeking to minimize these effects, nanostructured carriers of radioisotopes have been studied with the aim of improving the specificity of action of ionizing radiation, delivering and retaining adequate amounts of radioactive isotopes within tumor cells, leading them to death. In the present work, silica nanoparticles were prepared in order to evaluate their capacity to act as a nanocarrier of the 159Gd-DTPA-BMA radioactive complex, which can selectively deliver high radiation doses to tumors. Furthermore, this formulation seeks to prevent nontarget tissues from receiving excessive amounts of radiation, acting as a new potential alternative to conventional radiotherapy, in which a large dose of radiation is delivered to nontarget tissues, causing harm to healthy surrounding tissues.

PAIR INSTABILITY SUPERNOVAE: LIGHT CURVES, SPECTRA, AND SHOCK BREAKOUT

For the initial mass range (140 < M < 260 Msun) stars die in a thermonuclear runaway triggered by the pair-production instability. The supernovae they make can be remarkably energetic (up to ~10^53 ergs) and synthesize considerable amounts of radioactive isotopes. Here we model the evolution, explosion, and observational signatures of representative pair-instability supernovae (PI SNe) spanning a range of initial masses and envelope structures. The predicted light curves last for hundreds of days and range in luminosity, from very dim to extremely bright, L ~ 10^44 ergs/s. The most massive events are bright enough to be seen at high redshift, but the extended light curve duration (~1 year) -- prolonged by cosmological time-dilation -- may make it difficult to detect them as transients. An alternative approach may be to search for the brief and luminous outbreak occurring when the explosion shock wave reaches the stellar surface. Using a multi-wavelength radiation-hydrodynamics code we calculate that, in the rest-frame, the shock breakout transients of PI SNe reach luminosities of 10^45-10^46 ergs/s, peak at wavelengths ~30-170 Angstroms, and last for several hours. We explore the detectability of PI SNe emission at high redshift, and discuss how observations of the light curves, spectra, and breakout emission can be used to constrain the mass, radius, and metallicity of the progenitor.

Biocompatible magnetic polymer carriers for in vivo radionuclide delivery.

The magnetic guidance of antiplastic and antibacterial agents as well as x-ray and MRI contrast substances in vivo by means of magnetic particles has been attempted repeatedly during the last 2 decades with more or less success. When using microparticles, the circulation time in the blood, the biodistribution, and to a greater or lesser extent, the specific targeting are determined by the uniformity of size, chemical composition, surface modification, and the electric surface charge. The electrophoretic mobility is an important parameter for the prediction of the usefulness of the prepared particle, modified by chemical and biological molecules. For its success, radionuclide therapy depends on the critical relationship between the amount of radioactive isotopes in the target tissue and in critical normal tissue. Because the implementation of radioimmunotherapy for the treatment of cancer has proven to be considerably more difficult than initially anticipated, we propose the use of magnetic nanospheres for the well directed delivery of radionuclides to a tumor after the intravenous administration of the biodegradable colloidal suspension.

Maternal-fetal transport of iron and iodine in human subjects.

Information on the absorption, distribution and metabolism of normal body constituents as well as drugs, and toxic materials in man is difficult to obtain. The development of tracer techniques has made it possible to label various components and to follow the distribution of the labelled material. In many circumstances, it is possible to use small amounts of radioactive isotopes as labels, and with this technique accurate results can be obtained with simplicity. In some circumstances, especially in normal pregnant subjects or in normal newborn infants, it is not possible to justify the use of radioactive tracers. In these situations, the same kind of information can often be obtained with stable tracers. This paper will summarize data we have obtained on maternal-fetal transport of the radioactive tracers 131I and 59Fe in women receiving therapeutic abortions and of the stable tracer 58Fe in normal pregnancies.

Fixation of Radioactivity in Solid Media: Stability of Glasses and Glazes

A standard leaching test employed for the evaluation of the stability of glasses and glazes was used to test the fixation of radioactivity in solid media. Results are reported from preliminary tests of the leaching apparatus and from tests using samples of glass prepared with small added amounts of Cs/sup 137/ tracer. The release of activity was found to be proportional to the area of the exposed surface. It was concluded that the amount of radioactive isotope required in a test specimen would vary with the nature of the isotope and the type of measuring equipment available to the operator. (C.H.)

Relationship of the parathyroids to bone phosphorus.

In an attempt to determine if parathyroid action on bone was directly related to the dissolution of bone crystals, rats were injected with radiostrontium and radiophosphorus at 18 hours and at 3 weeks prior to nephrectomy or nephrectomy-parathjToidectomy and peritoneal lavage. In the parathyroidectomized animals there was a decrease in both calcium and phosphorus removal during the lavage, the decrease in phosphorus being about half that of calcium. The amounts of radioactive isotopes removed by lavage were not affected by parathyroidectomy in the animals injected 18 hours prior to lavage. In the animals injected 3 weeks prior to lavage the amounts removed from the parathyroidectomized animals were less in all cases. Parathyroidectomy caused a 25% drop in radiostrontium removal and an 18% drop in radiophosphorus removal. The 2:1 decrease in weight of calcium over phosphorus removed and the 3:2 decrease in radiostrontium over radiophosphorus previously formed bone crystal. It is suggested that the parathyr...

Total exchangeable sodium in the menstrual cycle

T HE purpose of the study was to do serial measurements of total c~~hangeable body sodium in women throughout the menstrual cycle to determinc~ whether there is a sodium retention during normal menstrual cycles. It is common belief that there are changes in body sodium content in pregnancy, tosemia of pregnancy, the premenstrual tension syndrome,g and perhaps also in the normal menstrual cycle. The intent was to establish normal control values and ranges for body sodium content, and to determine the daily pattern of body sodium for possible changes concomitant with the endocrinologic changes of the normal menstrual cycle. Serial measurements of total exchangeable hod? sodium were made on a daily basis with the use of isotope dilution techniques. Sodium metabolism can be studied by metabolic balance methods, or, as has been done more recently, by isotope dilution techniques.4, 16-19 When a known amount of radioactive isotope is administered, it exchanges or is diluted by the naturally occurring element in the body, and the total amount of bod3 element with which the tracer isotope has exchanged or mixed can bc calculated by the dilution principle. That is, if the concentration of radioactive isotope is known or measured before and after dilution in the body, t,he volume. or weight of the diluting substance can be calculated. The basis of the method is the chemical dilution principle that the weight or mass of the diluted solute or tracer substance remains constant before and after dilution, expressed by the formula C,V, = &V,, where C and V represc>nt concentration and volume before and after dilut,ion. The method is suitable for volume or ‘ ‘space, ’ ’ and solid or weight studies using either dyes ot’ isotopes, and was first used by Keith, Rowntrec, and Geraghty” in 1915 for dye studies measuring plasma volume. The method has been popularized in the United States by F. D. &loore and his co-workrrs. Dilution studies with the radioactive isotopes are based on observations that the tracer isotopes behave chemically and physically in the body in a maw ner identical with that of the natural isotopes of an element, except that a proportion of the radioactive atoms will (lisintegl-ale with the cmissiwl of ~xdiatiolr which can be detected, measured, and rc~c’otde(l.“”

Temporary Preservation of Carcasses of Small Laboratory Animals containing Radioactive Isotopes

THE safe disposal of carcasses containing radioactive isotopes often presents a difficult problem. Even if a specially designed incinerator is available, it is still important that the amount of radioactive isotope in the material to be burned is kept as low as possible.

Excretion of Radio-Sodium Following Intravenous Administration in Man

After the first extensive internal use of naturally radioactive compounds in man by Proescher and others,1, 5 Seil, et al.,6 estimated that from 40% to 60% was lost from the body, chiefly through the feces. A progressive diminution in the rate of excretion was indicated by Schlundt and his group,7 who found that patients retained 4.3% 6 months after administration and 1.9% 6 months later. Sehlundt and Failla8 found 24 μgm. and 14 μgm. respectively in 2 women 12 years after oral ingestion of radium, with respective coefficients of excretion of .005% and .0025%. Prolonged retention has been reported in many cases of industrial radium poisoning.9, 10Following the announcement by Curie and Joliot11 of the preparation of an artificial radioactive isotope of nitrogen in 1934, Lawrence and his co-workers12 produced relatively large amounts of radioactive isotopes of many elements using their magnetic resonance accelerator. Radio-sodium became available for clinical study at the University of California Hospital ...