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1.
Maghemite nano-particles were synthesized by a solid-state chemical reaction for its highly selective use as, cyclotron-produced, 109Cd (462.9 days) purification method of choice. 109Cd radiochemical separation starts with Ag activities precipitated with HCl 0.0015 M followed by, on a second step, 109Cd separation from Cu carrier and 65Zn (243.8 days) using Ca (NO3)2 0.01 M. Experimental parameters such, pH and sorbent concentration, on 109Cd extraction efficiency were investigated. Phase morphology, nanostructure and size of nano-particles were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A 10–20 nm average grain size was derived from XRD line broadening and SEM data. Heat treatment on Fe3+:Fe2+ ratios equal to 2:1, produced powders, resulting in tetragonal (maghemite) structure at 300 °C and rhombohedra (hematite) at 600 °C. 109Cd chemical and radionuclidic purity were determined by ICP-AES and HPGe detector gamma-ray spectrometry. The overall recovery and radionuclide purity were 80.0% from obtained 129.63 kBq/C MeV (70 kBq/μAh) initial activity and 91.4%, respectively.  相似文献   

2.
A procedure for preparation of 99Mo/99mTc radioisotope generator based on low specific activity neutron activated 99Mo was developed. Aluminum molybdate(VI)-99Mo of high Mo(VI) content (~?364 mg/g Al99Mo) was prepared by mixing low specific activity molybdate(VI)-99Mo and aluminum mixture solution with isoamyl alcohol. Al99Mo gel matrix was precipitated when the pH of the mixture solution was raised to ~?5 by addition of NaOH to the mixture. Radiometric measurements indicate the strong fixation of Molybdate(VI)-99Mo species in the form of the sparingly insoluble Al99Mo gel matrix. The prepared AlMo gel matrix was physiochemically characterized. Al99Mo gel matrix was used as a base material for preparation of 99Mo/99mTc generator. The 99mTc eluted from 99Mo/99mTc radioisotope generator was found to have relatively high elution yield (84?±?2.3%), radionuclidic (≥?99.99%), radiochemical (98.1?±?0.9%) and chemical purity.  相似文献   

3.
A sediment core was taken to determine if sediment accumulation rates could be conducted using 240+239Pu signatures in the coastal mangrove mudflats of southeastern Brazil. The results from this study show that 240+239Pu fallout activities are sufficient and well preserved in the coastal sediments of this region. Sediment accumulation rates determined from the 240+239Pu signatures were 4.4 mm/year and 4.1 from 210Pb (CIC) method. A sediment mixing coefficient rate was calculated using chlorophyll-a profile (9.5 cm2).  相似文献   

4.
Protactinium and thorium activities were measured in eight surface sediment taken in 2004 to determine effectiveness scavenging of 231Pa at Sabah–Sarawak coastal waters. The result found that activity ratios of 231Paex/230Thex were ranged from 0.07 to 0.13 at all sampling stations. The high 231Paex/230Thex activity ratio than the production ratio of 0.093 in seawater at station SR 01, SR 02, SR 04, SB 02 and SB 05, revealed that 231Pa is effectively removed from the water column into the sediment in comparison with 230Th at those stations. Low percentage of 230Thex (90–95%) in comparison with 231Paex at all stations can be attributed to less efficiently scavenged of 230Th onto particles prior deposited at the marine sediment bed.  相似文献   

5.
A radiotracer gas with a blend of 37Ar and 127Xe was created for a gas migration experiment and was characterized at Pacific Northwest National Laboratory using ultra-low-background proportional counters. This paper describes the direct low-energy measurement of 37Ar and 127Xe in a dual-isotope sample. Using this low-energy technique, the dual-isotope radiotracer gas was determined to have activity concentrations of 483 Bq/cc and 1435 Bq/cc for 37Ar and 127Xe, respectively, and a ratio of 1:3 on the reference date of 7/11/2016.  相似文献   

6.
Coagulation factor VIII (FVIII) is a glycoprotein that plays a crucial role in the clotting cascade. Replacement therapies with recombinant and plasma-derived concentrates of FVIII are used for treatment of hemophilia A. We have previously purified the human plasma FVIII by immobilized metal affinity chromatography (IMAC) using Cu2+ as the metal ligand. In this work we report the purification of FVIII using Zn2+ and Co2+, two metal ions that bind proteins more weakly. Human plasma was directly applied to the anion-exchange ANX Sepharose FF column and the eluate was used as starting material for the studies in IMAC columns. Using imidazole as desorbing agent, FVIII was recovered with 65% activity in the IMAC-Zn2+ column and with 74% activity in the IMAC-Co2+ column. Purification factors were 4 and 9, respectively. Using a pH gradient, FVIII was eluted at pH 5.0 with 17% activity in the IMAC-Zn2+ and 77% activity in the IMAC-Co2+. Vitamin K-dependent proteins, a family of proteins that includes Prothrombin and coagulation factor IX, coeluted with FVIII in the ANX Sepharose FF column and were recovered with the unbound proteins on both IMAC columns. Therefore, Co2+ and Zn2+ columns were as effective as the Cu2+ column in separating FVIII from vitamin K-dependent proteins. Finally, we have shown that FVIII remained complexed with the von Willebrand factor.  相似文献   

7.
A procedure for recovery of 65Zn from acidic Ga-rich solutions generated in 68Ge production process was developed and implemented in a “hot cell” environment. A one step simple separation was carried out on anion exchange column filled with Biorad AG1-X8 resin. With 65Zn recovery yields of more than 95% this procedure is currently routinely used at Brookhaven Linac Isotope Producer.  相似文献   

8.
The station for pions cancer therapy was operated at PSI from 1980 to 1992. After a cooling time of 12 years it’s made of copper beam dump was cut and samples were taken for analytical purposes. The sampling collected about 500 g of high active copper chips that can be used for separation of exotic radionuclides. The analyses by gamma spectrometry, LSC and AMS showed main nuclides present to be 60Co, 54Mn, 22Na, 65Zn, 26Al, 53Mn, 59Ni, 63Ni, 55Fe and 60Fe and 44Ti with a daughter nuclide 44Sc. In the frame of ERAWAST project a procedure combining selective precipitation and ion exchange for the separation of the rare radionuclides from the copper beam dump was developed. The proposed separation procedure is easy for remote controlled implementation in a hot cell. The ion exchange separation of Ni, Al, Mg, Ti and Fe was complete and high decontamination factors for copper and cobalt were achieved. Based on the developed procedure a remotely controlled system for separation of exotic radionuclides from the copper chips was set up. The full scale system was installed in a hot cell where high activity levels can be handled. In order to evaluate the reliability and functionality of the system extensive tests have been done. During the test period 13.86 g in total of the proton irradiated copper beam dump were processed for separation of 26Al, 59Ni, 53Mn, 44Ti and 60Fe. The results showed that the system was operational and the radionuclide separation was selective with high chemical yield. The procedure manages as well the generated liquid wastes containing high level of 60Co activity.  相似文献   

9.
A sequential separation procedure has been developed for the determination of 99Tc, 94Nb, 55Fe, 90Sr and 59/63Ni in various radioactive wastes generated from nuclear power plants. Ion exchange and extraction chromatography were adopted for individual separation of the radionuclides. Precipitation was supplementarily utilized for both purification of the individual radionuclides and preparation of the radionuclide sources for use in a radioactivity measurement. The chromatographic separation behavior of the radionuclides both from the sample matrix metals and from one another was investigated using stable metals, Re (as a surrogate of 99Tc), Nb, Fe, Sr and Ni. The validity of the procedure for reliability and applicability was evaluated by measuring the recovery of the metal carriers added to synthetic radioactive waste solutions. The recoveries by the chromatographic separation were in the range of 84.8 to 102.2% with 2s of less than 8.6%, the recoveries by the precipitation being in the range of 84.3 to 97.3% with 2s of less than 10.9%.  相似文献   

10.
The radiochemical separation of the different radionuclides (64Cu, 67Cu, 67Ga, 66Ga, 56Ni, 57Ni, 55Co, 56Co, 57Co, 65Zn, 196Au) induced in the Ni supported Cu substrate — 68Zn target system, which was bombarded with the 29.0 MeV proton beam, was performed by ion-exchange chromatography using successive isocratic and/or concentration gradient elution techniques. The overlapped gamma-ray spectrum analysis method was developed to assess the 67Ga and 67Cu content in the 64Cu product and even in the post-67Ga production 68Zn target solution without the support of radiochemical separation. This method was used for the assessment of 64+67Cu radioisotope separation from 67Ga, the quality control of 64Cu product and the determination of the 68Zn (p,2p)67Cu reaction yield. The improvement in the targetry and the optimization of proton beam energy for the 68Zn target based 64Cu and 67Ga production were proposed based on the stopping power and range of the incident proton and on the excitation functions, reaction yields and different radionuclides induced in the target system.  相似文献   

11.
In various samples of Mytilus galloprovincialis, 210Po was determined by alpha-spectrometry while Mn, Fe, Ni, Cu, Zn, Cd, Sn, Hg and Pb by energy dispersive, polarised X-ray fluorescence spectrometry (EDPXRF). The mussels of different sizes were taken from 7 sites in the central Adriatic Sea along the Marche coastal region during the four seasons of the year. 210Po activity concentration ranged between 57 and 343 Bq·kg−1 dry weight. The concentration ranges of heavy metals (μg·g−1 dry weight) were as follows: Mn: 72.9–83.1; Fe: 45.1–754; Ni: 1.3–7.6; Cu: 17.9–156; Zn: 60.9–189; Cd: 0.6–1.0; Sn: 0.6–3.9; Hg always <0.5; Pb: 2.0–9.0. The data obtained depend upon the site and the period of the sampling and they are also compared with those obtained by other authors for the same organism in the Mediterranean and other Italian seas.  相似文献   

12.
Morin was successful as a chemical modifier to improve the reactivity of the nanometer SiO2 surface in terms of selective binding and extraction of heavy metal ions. This new functionalized nanometer SiO2 (nanometer SiO2-morin) was used as an effective sorbent for the solid-phase extraction (SPE) of Cd(II), Cu(II), Ni(II), Pb(II), Zn(II) in solutions prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental conditions for effective adsorption of trace levels of metal ions were optimized with respect to different experimental parameters using static and dynamic procedures in detail. The pH 4.0 was chosen as the optimum pH value for the separation of metal ions on the newly sorbent. Complete elution of the adsorbed metal ions from the nanometer SiO2-morin was carried out using 2.0 mL of 0.5 mol L−1 of HCl. Common coexisting ions did not interfere with the separation and determination at pH 4.0. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 22.36, 36.8, 40.37, 33.21 and 25.99 mg metal/g SiO2-morin for Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II), respectively. The time for 95% sorption for Cu(II) and Ni(II) and 70% sorption for Cd(II), Pb(II) and Zn(II) was less than 2 min. The relative standard deviation (RSD) of the method under optimum conditions was lower than 5.0% (n = 11). The procedure was validated by analyzing the certified reference river sediment material (GBW 08301, China), the results obtained were in good agreement with standard values. The nanometer SiO2-morin was successfully employed in the separation and preconcentration of trace Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II) from the biological and natural water samples yielding 75-folds concentration factor.  相似文献   

13.
Supplemental zinc as ZnO is routinely added to nursery pig diets at 15 to 20 times the nutritional requirement to alleviate physiological stress and enhance performance. The mechanism by which Zn accomplishes this function is unknown, however, high concentrations of Zn are excreted in the environment at undesirable levels. To study Zn uptake, we developed a multi-stage digestion model followed by exposure to swine intestinal brush border membrane vesicles (BBMV). We report on the feasibility of using a duel label (65Zn and 69mZn) to simultaneously quantify the competitive uptake of Zn from co-existing zinc supplements using our BBMV model.  相似文献   

14.
The concentrations of 210Po and 210Pb have been measured in soil, sediment and rock samples collected from major rivers of coastal Karnataka, viz. Kali, Sharavathi and Netravathi. The activity of 210Po and 210Pb in the samples were separated by radiochemical methods and the activity was counted using ZnS(Ag) alpha-counter. The activity ratio of 210Po and 210Pb and the dependence of organic matter content on the activity of these radionuclides were studied.  相似文献   

15.
Sitafloxacin dithocarbamate (SFDE) was synthesized, radiolabeled with technetium-99m (99mTc) using [99mTc-N]2+ core and evaluated its biological efficacy as a potential radiotracer for Staphylococcus aureus (S. aureus) infection in artificially infected rats (AIRT) and rabbits (AIRB). The radiochemical stability of the 99mTc labeled SFDE (99mTcN-SFDE) in saline and serum was determined by radio-HPLC and TLC methods, respectively. After, 1 min of reconstitution the value of radiochemical purity (RCP) was 99.00 ± 0.20% and was remained more than 90% unwavering even after 240 min of the radiolabeling. The 99mTcN-SFDE complex showed similar radiochemical permanence behavior in serum at 37 °C. The complex showed almost six fold higher specific in vitro binding with living than heat killed S. aureus. Biodistribution behavior was evaluated in S. aureus AIRT and whole body imaging (WBI) in AIRB, respectively. Seven fold up take was observed in infected muscle of the AIRT as compared to inflamed and normal muscles. The disappearance of activity from blood and appearance in urinary system indicated normal route of excretion of the complex. Scintigraphically, it was confirmed that the labeled SFDE was higher accumulated in the infected muscle higher than in inflamed and normal muscle. The high radiochemical stability in saline and serum, specific in vitro binding with S. aureus, precise in vivo distribution in S. aureus AIRT and targeted WBI in AIRB confirmed the possibility of the 99mTcN-SFDE complex as a potential and promising S. aureus infection radiotracer.  相似文献   

16.
Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H2SO4 or HCl were evaluated in freshwater sediments using 197Hg radiotracer. Values obtained for the 197Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of 197Hg2+ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg2+ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg2+ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H2SO4 method is recommended, since it is free from these interferences. 197Hg radiotracer (T 1/2 = 2.673 d) has a production rate that is about 50 times higher than that of 203Hg (T 1/2 = 46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to 203Hg when it is used it in short-term experiments and produced by the irradiation of 196Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the 196Hg isotope is increased, the specific activity of the 197Hg tracer can be significantly improved. In the present work, 197Hg tracer was produced from mercury 51.58% enriched in the 196Hg isotope, and a 340-fold increase in specific activity with respect to natural mercury targets was obtained. When this high specific activity tracer is employed, mercury methylation and reduction experiments with minimum mercury additions are feasible. Tracer recovery in methylation experiments (associated with Me197Hg production from 197Hg2+ spike, but also with Hg2+ contamination and Me197Hg artefacts) with marine sediments was about 0.005% g−1 WS (WS: wet sediment) after 20 h incubation with mercury additions of 0.05 ng g−1 WS, which is far below natural mercury levels. In this case, the amount of Hg2+ reduced to Hg0 (expressed as the percent 197Hg0 recovered with respect to the 197Hg2+ added) varied from 0.13 to 1.6% g−1 WS. Me197Hg production from 197Hg2+ spike after 20 h of incubation of freshwater sediment ranged from 0.02 to 0.13% g−1 WS with mercury additions of 2.5 ng g−1 WS, which is also far below natural levels. 197Hg0 recoveries were low, 0.0058 ± 0.0013% g−1 WS, but showed good reproducibility in five replicates. Me197Hg production from 197Hg2+ spiked in freshwater samples ranged from 0.1 to 0.3% over a period of three days with mercury additions of 10 ng L−1. A detection limit of 0.05% for Me197Hg production from 197Hg2+ spike was obtained in seawater in a 25 h incubation experiment with mercury additions of 12 ng L−1.  相似文献   

17.
Electrophilic substitution reactions Zn2+ M2+ (M = Mn, Co, Ni, Cu, Cd) in thin gelatin layers with immobilized zinc(II) hexacyanoferrate brought in contact with the aqueous solutions of d-element chlorides are studied. In all cases (except for Mn(II)), Zn atoms are partially replaced by all metals in question with the formation of the corresponding binuclear ZnM hexacyanoferrates(II). No complete replacement of Zn(II) to mononuclear hexacyanoferrate(II) of substituting metal occurs in neither of the cases.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 110–116. Original Russian Text Copyright © 2005 by Tatarintseva, Mikhailov, Naumkina, Lygina.  相似文献   

18.
An intercomparison of the methodology (alpha, beta and gamma spectrometry) used for 238U, 235U and 210Pb determination was carried out based on 38 sediment samples. The activity range of the samples varied from 10–700 Bq/kg for 210Pb, 1–35 Bq/kg for 235U and 10–800 Bq/kg for 238U. Results obtained using the three methods were not statistically different at high activity levels, but agreement between the results decreased at lower sample activity levels. For 210Pb, the smallest difference was found between alpha and gamma spectrometry. A good correlation between results from alpha and gamma spectrometry was observed over the whole activity range. In beta spectrometry, the results were slightly higher than those obtained by alpha or gamma spectrometry due to the impurity of 228Ra. In 238U analysis, good correspondence was observed between 238U determined by gamma and alpha spectrometry, particularly at higher 238U activity concentrations over 100 Bq/kg. In 235U analysis, attention needs to be paid to interference from 226Ra and its reduction.  相似文献   

19.
Feather fibers were modified by treatment with 5% tannic acid (TA) solution. Kinetics of the modification was investigated as a function of the reaction time. The maximum loading of TA on feather reached 8.3% after being treated by TA for 9 h. The adsorption of metal cations (Cu2+, Zn2+) by unmodified and TA-modified feather fibers was investigated as a function of fiber weight gain, temperature, and pH of the metal solution. The adsorption was enhanced at alkaline pH and ambient temperature and increased with the weight gain of TA. The maximum uptake of metal cations (Cu2+, 0.77 mmol/g; Zn2+, 0.95 mmol/g) was obtained by TA-modified feather at weight gain: 8.3%, pH 11, while at the acidic pH, the adsorption of metal cations by either unmodified or TA-modified feather was negligible. The influence of anions on the adsorption of metal cations was also studied. The uptake of Cu2+ from chloride was higher and faster than that from nitrate. Desorption of the metals was performed at acidic pH 2.5 for 48 h. The feather–TA–metal complexes exhibited higher stability for metal cations than the feather–metal complexes. All these experiments reveal that TA-modified feather fibers have good adsorption to metal cations and can be used as metal adsorbent in wastewater treatment.  相似文献   

20.
The zirconium silicotungstate (ZrSiW) was studied as an effective sorbent material to be used in the 113Sn/113mIn generator. The results elucidated that the distribution coefficient of 113Sn (3700 mL/g) is greater than 113mIn (275 mL/g) from 0.1 M HCl acid solution to the ZrSiW material. The maximum sorption capacity of Sn (IV) was found to be 33 mg per gram ZrSiW (~?0.3 mmol/g). The elution yield of 113mIn was found to be >?78?±?6.4% with an acceptable purity of radionuclidic and radiochemical (≥?99.99 and 96.8%, respectively). The rigorous separation of 113mIn from the 125Sb was carried out due to its long half-life (2.758 years) and beta emission that causes tissue damage. Zr, W and Si levels are below the permitted limit in the 113mIn eluate.  相似文献   

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