Volume 109, Issue 6

Hexapropyl phosphoramide (HPPA) and hexabutyl phosphoramide (HBPA) were examined for the macrolevel extraction and stripping of tetravalent metal ions such as Pu(IV) and Th(IV). The solvation number of Pu(IV) with both the phosphoramides were measured. The number of stages was evaluated for the quantitative extraction and stripping of Pu(IV) and Th(IV) in cross-current mode with 1.1 M phosphoramides in xylene from the nitric acid medium. The distribution ratios for the extraction of Th(IV) were measured with 1.1 M phosphoramides in xylene as a function of equilibrium aqueous phase Th(IV) and nitric acid concentration. In addition, distribution ratios for the extraction of fission product elements such as Zr, Tc, Ru, lanthanides (La, Pr, Nd and Gd) and activation product Am were also measured with 1.1 M HPPA and HBPA in n -Dodecane ( n -DD) system as a function of aqueous phase nitric acid concentration. The extraction data generated with phosphoramides were compared with a 1.1 M TBP/ n -DD system.

The solubility of Nd(III), Th(IV) and U(VI) was studied from undersaturation conditions in the presence of selected organic cement additives and model compounds: adipic acid, methyl acrylate, citric acid, melamine, ethylene glycol, phthalic acid and gluconic acid. Experiments were performed under Ar atmosphere in NaCl (2.5 and 5.0 M), MgCl 2 (1.0 and 3.5 M) and CaCl 2 (1.0 and 3.5 M) solutions with 9 ≤ pH m  ≤ 13 (pH m  = −log[H + ]). Initial concentrations of organic ligands in solution were set constant in all systems to [ L ] 0  = 0.025 M, except in specific cases ( e.g. adipic acid, melamine and phthalic acid) where the ligand concentration in the matrix solutions was lower and controlled by solubility. Adipic acid, methyl acrylate, melamine, ethylene glycol and phthalic acid do not impact the solubility of Nd(III), Th(IV) and U(VI) in the investigated NaCl, MgCl 2 and CaCl 2 systems. Citrate significantly enhances the solubility of Nd(III), Th(IV) and U(VI) in NaCl systems. A similar effect was observed for Th(IV) and U(VI) in the presence of gluconate in NaCl systems. The impact of pH on the stability of the complexes is different for both ligands. Because of the larger number of alcohol groups in the gluconate molecule, this ligand is prone to form more stable complexes under hyperalkaline conditions that likely involve the deprotonation of several alcohol groups. The complexation of gluconate with U(VI) at pH m  ≈ 13 is however weaker than at pH m  ≈ 9 due to the competition with the highly hydrolysed moiety prevailing at pH m  ≈ 13, i.e. UO 2 (OH) 4 2− . The impact of citrate and gluconate in MgCl 2 and CaCl 2 systems is generally weaker than in NaCl systems, expectedly due to the competition with binary Mg-L and Ca-L complexes. However, the possible formation of ternary complexes further enhancing the solubility is hinted for the systems Mg/Ca-Th(IV)-GLU and Ca-U(VI)-GLU. These observations reflect again the differences in the complexation properties of citrate and gluconate, the key role of the alcohol groups present in the latter ligand, and the importances of interacting matrix cations. The screening experiments conducted within this study contribute to the identification of organic cement additives and model compounds potentially impacting the solution chemistry of An(III)/Ln(III), An(IV) and An(VI) under intermediate to high ionic strength conditions (2.5 ≤  I  ≤ 10.5 M). This shows evident differences with respect to investigations conducted in dilute systems, and thus represents a very relevant input in the safety assessment of repositories for radioactive waste disposal where such elevated ionic strength conditions are expected.

Liquid-liquid extraction system consisting of oxytetracycline (HOTC) in dichloromethane was developed for extraction of Nd +3 and Eu +3 from acidic solutions using radiometric technique. Various extraction parameters such as pH, equilibration time and metals concentration were optimized. Slope analysis method was used to study the composition of product and was found to be M(OTC) 3 [here M=Nd +3 or Eu +3 and OTC = conjugate base of HOTC]. Among cations Al +3 and Fe +3 while among anions F − effected the extraction of these metals. Higher separation factor of these metals was found with many others. The method was successfully applied on spiked sea water.

A carrier-free 124 Sb tracer was prepared for determining radioactive 125 Sb in highly contaminated and radioactive soil like one taken near the Fukushima Daiichi Nuclear Power Plant. The excitation function for the 124 Sb production was measured and compared to previous works to identify the optimum proton energy for the 124 Sn (p, n) reaction by a stack method. The maximum production of 124 Sb in the reaction was found at an incident proton beam energy of 8–9 MeV. Except for 124 Sb, the reaction produced short-lived by-products and practically no 125 Sb. Antimony was isolated from tin matrix by dissolving the irradiated target and extracting to isoamyl acetate. Then the carrier-free 124 Sb tracer solution was purified by passing it through an anion exchange resin column. The radioactivity of 124 Sb was recovered to more than 50% of the production, and provided successfully as a tracer solution free from tin due to the examined chemical procedure.

The rapid progress of nanomedicine field has a great influence on the different tumor therapeutic trends. It achieves a potential targeting of the therapeutic agent to the tumor site with neglectable exposure of the normal tissue. In nuclear medicine, nanocarriers have been employed for targeted delivery of therapeutic radioisotopes to the malignant tissues. This systemic radiotherapy is employed to overcome the external radiation therapy drawbacks. This review overviews studies concerned with investigation of different nanoparticles as promising carriers for targeted radiotherapy. It discusses the employment of different nanovehicles for achievement of the synergistic effect of targeted radiotherapy with other tumor therapeutic modalities such as hyperthermia and photodynamic therapy. Radiosensitization utilizing different nanosensitizer loaded nanoparticles has also been discussed briefly as one of the nanomedicine approach in radiotherapy.

In this work, the radiotracer [ 99m Tc]nitrido-oxiracetam complex was labeled in the presence of 99m Tc-nitrido as a core. In order to get the highest radiochemical purity, many effective factors have been studied such as temperature of the reaction, time of the reaction, the pH of the reaction mixture, substrate amount, and stability to give high percent more than 99%. Finally, biodistribution studies have been indicated the convenience of [ 99m Tc]nitrido-oxiracetam as a new radiotracer that could be used in brain imaging. Giving a maximum uptake of 10.6% at 30 min post injection.

Chicken eggshell powder (ESP) as natural source of CaCO 3 was incorporated as natural filler into High Density Polyethylene (HDPE).This natural source can be considered as an effective alternative for the commercial calcium carbonate (CC) filler. Characterization of ESP and CC was investigated by FTIR and XRD analysis. HDPE composites filled with 30 phr (ESP) and (CC) were prepared using internal mixer. 2 phr maleic anhydride (MA) was added as compatibilizing agent to HDPE/ESP composite. The prepared composites were vulcanized by using γ -radiation at doses from 50 to 150 kGy. Mechanical and flame retardancy properties of all composites were investigated; composites were thermally analyzed using TGA and DSC. The results showed that, the mechanical properties of HDPE decrease by incorporation of ESP or CC into it, as it was noticed that the mechanical properties of HDPE/ESP composite were better than the mechanical properties of HDPE/CC composite. Moreover, addition of MA led to improvement in mechanical properties of the HDPE/ESP composite. As well, the thermal stability and flame retardancy of the composites increased by adding ESP or CC to HDPE. The results were proved by scanning electron microscopy (SEM).

Psoriasis is a dermatological disease that affects 2–3% of the Algerian population. Selenium has a positive impact on psoriasis. Selenium plays an important role in protecting free radical damage as a component of the glutathione peroxidase enzyme. The objective of this investigation was to assess the status of selenium in the hair of Algerian patients suffering from psoriasis. Fifty-eight scalp hair samples were collected from Algerian patients with psoriasis, classified by gender and four age groups: 36 females and 22 males, aged between 9 and 79 years. Thirty healthy subjects aged 9–74 years were also surveyed for control purposes. Selenium content was measured for all scalp hair samples using the k 0 -standardization of neutron activation analysis. The average selenium concentration for controls and patients were 0.39 ± 0.18 and 0.28 ± 0.13 μg/g respectively. Selenium concentration for female and male controls and patients, were 0.35 ± 0.17, 0.47 ± 0.19, 0.28 ± 0.14, and 0.28 ± 0.11 μg/g, respectively. There is a significant difference ( p  < 0.05) between selenium level in patients and in controls. Selenium concentrations in psoriatics’ scalp hair can be affected by both gender and age. Measured selenium contents have been approved by the quality assurance and quality control procedure (QA/QC).

A CR-39 based method was developed for measuring the ultra-trace alpha radio activities in aqueous samples having curie levels of γ/β-radio activities. The chemical etching method was optimized to reveal the alpha tracks in CR-39. This new chemical etching method involved the use of a phase transfer catalyst tetraethylammonium bromide which reduced the track revelation induction time without deteriorating the track-etch parameters. The alpha track-etch parameters such as bulk-etch rate, track-etch rate, induction time, and the critical angle of alpha track registration were measured at 60 and 70 °C, with and without using a phase transfer catalyst in the chemical etching for the comparison and optimization. The track registration efficiency of CR-39 in the solution medium was measured using the samples having known alpha activity of mix Pu, and value obtained was found to be (4.42 ± 0.12) × 10 −4  cm. The registration efficiency value thus obtained was corroborated with the expected efficiency expected from the calculated range of alpha particles in the solution. This CR-39 based method was employed to quantify the alpha activity, as low as 0.2 Bq mL −1 , in the aqueous radiopharmaceutical samples having the curie levels of γ/β radio activities.