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[en] A method for the speciation of chromium(III), chromium(VI) and determination of total chromium based on coprecipitation of chromium(III) with dysprosium hydroxide has been investigated and applied to tap water samples. Chromium(III) was quantitatively recovered by the presented method, while the recovery values for chromium(VI) was below 10%. The influences of analytical parameters including amount of dysprosium(III), pH, centrifugation speed and sample volume for the quantitative precipitation were examined. No interferic effects were observed from alkali, earth alkali and some transition metals for the analyte ions. The detection limits (k = 3, N = 15) were 0.65 μg/L for chromium(III) and 0.78 μg/L for chromium(VI). The validation of the presented method was checked by the analysis of certified reference materials.
[en] The present study is on the calculation of the hyperfine splittings in Dy(OH)3 and Ho(OH)3, using the electronic energy level pattern for these ions, obtained from previous studies. The internal magnetic field is found to be larger in the holmium compound whereas the quadrupolar interaction is in the reverse order. (author)
[en] Full text: Severe, debilitating pain accompanies inflammation of the synovial membrane in rheumatoid arthritis. Under certain conditions, radiation synovectomy is an effective alternative to surgery for relief of these symptoms. Radionuclides which decay by the emission of beta particles, or beta plus low yields of gamma/x-rays are indicated for this medical application. Of the radionuclides with appropriate decay emissions, half-life and physical/chemical properties, 165Dy is a suitable candidate for production in a low-power reactor. Literature methods for production of this radiopharmaceutical usually involve irradiating solid Dy(OH)3 , which is dissolved in HCl to form DyCl3 and then re-precipitated under controlled conditions using NaOH, to produce the desired particle size for medical use. A procedure in which most or all of this post-irradiation processing can be eliminated is particularly important when using low neutron flux reactors, in order to avoid reductions in the amount of deliverable radiopharmaceutical. Radiological safety considerations may also necessitate avoiding post-irradiation processing, since low-power reactor facilities usually have no appropriate hot cells for extensive manipulation of highly active samples. Appropriately-sized, pre-formed Dy(OH)3 particles were produced under a variety of conditions in attempts to produce a stable, sodium-free product that would be suitable for irradiation and use without further processing. Sodium content could be reduced to about <5 ppm by washing with pure water, but further washes seriously eroded the Dy particles, so that the majority of the particles remaining were <1 μ, too small for use in radiation synovectomy. Exploratory irradiation's were performed to confirm that usable specific activities were attainable in sufficient yield for medical use. Data on 165Dy production yields and particle characteristics will be presented in support of this concept
[en] Thermal destruction of indium and dysprosium hydroxides coprecipitated from solutions of their nitrate and chloride salts with ammonia was investigated by DTA/TG, XRD and MS methods. The features of these processes were revealed in solutions of different nature. It is shown that the method of thermal decomposition of mixed indium and dysprosium hydroxides coprecipitated from the solution of their chloride salts is environmentally appropriate and economically viable. The size of the coprecipitated hydroxide particles of indium oxide produced through thermal destruction at up to 500 °C (13 nm) allows us to recommend this method for production of nanodispersed mixed oxides of indium and dysprosium.
[en] The electric quadrupole and magnetic hyperfine interactions measured from the 161Dy Moessbauer resonance in crystalline Dy(OH)3 and from the 166Er resonance in crystalline Ho(OH)3 and Er(OH)3 are interpreted using the crystal field and molecular exchange field model. The crystal field parameters established from previous optical spectroscopy results account well for these hyperfine parameters. The crystal-field and magnetic properties of these ferromagnetic insulators are described well within the model
[en] A procedure for the determination of trace amounts of Pb(II), Cu(II), Ni(II), Co(II), Cd(II) and Mn(II) is described, that combines atomic absorption spectrometry-dysprosium hydroxide coprecipitation. The influences of analytical parameters including amount of dysprosium(III), centrifugation time, sample volume, etc. were investigated on the recoveries of analyte ions. The effects of concomitant ions were also examined. The recoveries of the analyte ions were in the range of 95.00-104.00%. The detection limits corresponding to three times the standard deviation of the blank for the analytes were in the range of 14.1-25.3 μg/L. The method was applied to the determination of lead, copper, nickel, cobalt, cadmium and manganese ions in natural waters and table salts good results were obtained (relative standard deviations <10%, recoveries >95%)
[en] Highlights: ► The sheet-shaped dysprosium hydroxide nanosquares were successfully synthesized. ► Synthesized by a facile hydrothermal method without using any catalysts or templates. ► The advantages of the method are rapid synthesis at air atmosphere, 100% productive ratio and low cost. ► It can be easily scaled up and might represent a promising method for industrial production. ► The role of the alkaline sources and the formation mechanism were discussed. -- Abstract: In this study, we succeed in synthesizing the sheet-shaped dysprosium hydroxide (Dy(OH)3) nanomaterials via a facile hydrothermal method without using any catalysts or templates. The advantages of the method are rapid synthesis at air atmosphere, 100% productive ratio and low cost with a great potential for scale-up. Analytical method such as XRD, FESEM, TEM, HRTEM, SAED, EDS, FT-IR, TG–DSC were employed to characterize the morphology and microstructure of the as-synthesized products. The results reveal that nanosheets could be obtained by using ammonia and sodium hydroxide, and the Dy(OH)3 obtained by adding ammonia possesses uniform sheet-shaped nanosquare morphology with the side length of 200–300 nm and thickness of 20–40 nm. The growth of (0 0 1) plane of nanosheets was confined. The presence of a two dimensional (2D) growth trend was suggested. The role of the alkaline sources and the formation mechanism of such sheet-shaped Dy(OH)3 were discussed
[en] 1. Development of 165Dy-HMA for the treatment of rheumatoid arthritis 1) Irradiation of 12 mg of 164Dy2O3 in a neutron flux 2x1013 n/cm2.sec for 4 hours gave 165Dy2O3 showing relatively high specific activity (480 mCi/mg Dy2O3) and pure radionuclidic purity (>99.9%). 2) 165Dy-HMA was prepared from 165Dy2O3 in yield of 80-85% and whose particles size was in 3-8μm range (> 90%) having high stability in vitro. 3) Scintiphoto of rabbit at 24 hours after administration of 165Dy-HMA into knee joint of a hind leg exhibited the retention of radioactivity with negligible leakage indicating high in vivo stability. 2. Development of 166Ho-PLAM for the treatment of liver cancer 1) The complex of 165Ho and acetylacetone was made by reacting aqueous HoCl3 (pH 5.0) solution with aqueous acetylacetone (pH 9.0) solution, and then recrystalization of the crude product from ethanol gave a pure complex (165Ho-AcAc) in yield of 58%(mp > 280deg C). 2) Chloroform(1 ml) containing polylactic acid (50 mg) and 165Ho-AcAc(30 mg) was added to 3% aqueous PVA solution with vigorous stirring, and then microsieving of produced particles gave 165Ho-PLAM whose size was in 10-45μm range. 3) 165Ho-PLAM was irradiated by neutron and the subsequent MCA analysis exhibited radionuclidic purity > 99.9% and weight content, respectively. 4) Suspension of 166Ho-PLAM in human plasma at room temperature for 7 days exhibited very low amount of leaching radioactivity(=0.9%) into plasma indicating in high in vitro stability. 5) Scintiphotos of rabbit taken at 24 hours after i.v administration of 166Ho-PLAM exhibited excellent retention in lung indicating that the prepared 166Ho-PLAM has high in vivo stability. (Author)
[en] Laws of coprecipitation of neodymium and dysprosium from zinc sulfate solution during partial precipitation of dysprosium with alkali are studied. Neodymium and dysprosium coprecipitation is carried out at pH 6.7-6.8 the number of ree in 15 ml of the solution is 30 mgk, the mass of collection is 0.23 mmol. The process of coprecipitation is of ion-exchange character. The sorbing part of ree grows with increase of pH solution. 3 refs.; 1 fig.; 3 tabs