PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “COBALT, RADIOACTIVE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed2006

Preparation and evaluation of cerium(IV) tungstate powder as inorganic exchanger in sorption of cobalt and europium ions from aqueous solutions.

Cerium(IV) tungstate powder was chemically synthesized and exploited as adsorbent material for the decontamination study of cobalt and europium ions from radioactive waste solutions under simulated conditions using batch technique. The influences of pH, particle size and temperature have been reported. The uptake of europium was found to be slightly greater than that of cobalt and the apparent sorption capacity increases with increase in temperature. Thermodynamic parameters such as changes in Gibbs free energy (DeltaG degrees), enthalpy (DeltaH degrees), and entropy (DeltaS degrees) were calculated. The numerical value of DeltaG degrees decreases with an increase in temperature, indicating that the sorption reaction of each ion was spontaneous and more favorable at higher temperature. The positive values of DeltaH degrees correspond to the endothermic nature of sorption processes and suggested that chemisorption was the predominant mechanism. A comparison of kinetic models applied to the sorption rate data of each ion was evaluated for the pseudo first-order, the pseudo second-order, intraparticle diffusion and homogeneous particle diffusion kinetic models. The results showed that both the pseudo second-order and the homogeneous particle diffusion models were found to best correlate the experimental rate data. The numerical values of the rate constants and particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy (E(a)) and entropy (DeltaS++) of activation were also computed from the linearized form of Arrhenius equation.

Adsorption↗
PubMed1989

[Value of angiography in the surveillance of choroid melanoma treated by cobalt disk].

Conservative management of choroidal melanoma by radioactive plaques or protonbeam is widely used since 1968. The treatment of these tumors at Curie Institute has been done with cobalt plaques since 1968. Indications were first monophthalmic patients but are now much wide. We have been treating since 1981 all patients with tumor diameter less than 17 mm and tumor height less than 12 mm. The technic includes general anesthesia to place the disc with localisation of the tumor by transillumination or by indirect ophthalmoscopy. A dose of 70 to 90 grays is delivered to the apex of the tumor. We report two cases of patients treated by cobalt 60 plaque for choroïdal melanoma. The first patient has a 5 mm high choroïdal melanoma temporal to the macula. After treatment by cobalt plaque, he showed no echographic changes but angiograms revealed an hypofluorescent zone in the central part of the tumor. The second patient has an 8 mm tumor that after plaque showed only angiographic changes. Evolution after treatment of choroïdal melanoma by radioactive plaque is variable. Echographic changes are very low and it is frequent to observe no modification in the height of the tumor for a long time for this reason, repeated angiograms can be very useful in the follow up of these patients. They frequently show hypofluorescent spot in the central part of a tumor that was hyperfluorescent before treatment. Sometimes there is diffuse lowering of the fluorescence. We think that these modifications of fluorescence can be due to diminution of the vascularisation of the tumor or may be to central necrosis of the tumor.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2007

Separation of iron and cobalt using 59Fe and 60Co by dialysis of polyvinylpyrrolidone-metal complexes: a greener approach.

An environmentally benign method to separate iron and cobalt has been developed using a safe chemical, polyvinylpyrrolidone (PVP). The method involves dialysis of PVP-Fe and PVP-Co complexes against triple-distilled water. (59)Fe and (60)Co were used as radioactive tracers of iron and cobalt throughout the experiment. No other chemicals are required for clean separation of cobalt from iron. The optimum condition for separation has been obtained at pH 5 using 10% aqueous solution of PVP. The method is applicable from trace scale to macro-scale. Very high separation factors have been obtained.

Cobalt↗
PubMed1976

Pharmacokinetic behaviour of bleomycin-cobalt-57 with special regard to intraarterial perfusion of the maxillo-facial region.

Bleomycin was traced by the isotope Cobalt-57. By using this radioactive substance the pharmacokinetic behaviour of the drug was examined. It was given either intravenously or intra-arterially or directly into the tumor in patients suffering from epidermoid carcinoma in the maxillo-facial region. The differences in the pharmacokinetic data are delineated. Practically, the intra-arterial route of administration is the best one because of the high adherence rate of the drug to the perfused tissue.

Bleomycin↗