Green solid synthesis of polyaniline-silver oxide nanocomposite for the adsorptive removal of ionic divalent species of Zn/Co and their radioactive isotopes 65Zn/ 60Co

A comparative study between two nanosorbents, nanopolyaniline (NPANI) and nanopolyaniline coated with nanosilver oxide (NPANI-NAg₂O) is explored to dispose the divalent species of Zn/Co from water and radioactive isotopes ⁶⁵Zn/⁶⁰Co from radioactive wastewater using batch and column techniques. NPANI-NAg₂O nanocomposite was synthesized via solid-solid reaction. Characterization was achieved using FT-IR, TGA, XRD, SEM, HR-TEM, and surface area analysis. The images of SEM and HR-TEM confirmed the success of the modification process and the particle size was found in the range 28.78-68.28 nm (NPANI) and 25.74-85.71 nm (NPANI-NAg₂O), respectively. Solution pH, contact time, solid dosage, and ionic concentration of the metals were studied as fundamental factors. The obtained results indicated that the optimum conditions to dispose Zn/Co divalent species using NPANI were pH 7 and 30-33 min, while NPANI-NAg₂O exhibited the optimum conditions at pH 7 and 20-30 min. The maximum removal capacities were 100.1 and 139.75 mg/g for Zn(II) and 57.93 and 112.1 mg/g for Co(II) using NPANI and NPANI-NAg₂O, respectively. Graphical abstract ᅟ.

Comparing single-feeding and multi-feeding approaches for experimentally assessing trophic transfer of metals in fish

Diet is an important pathway for metal uptake in marine organisms, and assimilation efficiency is one of the most relevant parameters to quantify trophic transfer of metals along aquatic food webs. The most commonly used method to estimate this parameter is pulse-chase feeding using radiolabeled food. This approach is, however, based on several assumptions that are not always tested in an experimental context. The present study aimed to validate the approach by assessing single-feeding and multiple-feeding approaches, using a model species (the turbot Scophthalmus maximus). Using the kinetic data obtained from the single-feeding experiment, the reconstruction of a multi-feeding experiment was tested for consistency with data provided by an actual multi-feeding performed under the same experimental conditions. The results validated the single-feeding approach. Environ Toxicol Chem 2017;36:1227-1234. © 2016 SETAC.

First PET Imaging Studies With 63Zn-Zinc Citrate in Healthy Human Participants and Patients With Alzheimer Disease

Abnormalities in zinc homeostasis are indicated in many human diseases, including Alzheimer disease (AD). ⁶³Zn-zinc citrate was developed as a positron emission tomography (PET) imaging probe of zinc transport and used in a first-in-human study in 6 healthy elderly individuals and 6 patients with clinically confirmed AD. Dynamic PET imaging of the brain was performed for 30 minutes following intravenous administration of ⁶³Zn-zinc citrate (∼330 MBq). Subsequently, body PET images were acquired. Urine and venous blood were analyzed to give information on urinary excretion and pharmacokinetics. Regional cerebral ⁶³Zn clearances were compared with ¹¹C-Pittsburgh Compound B (¹¹C-PiB) and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) imaging data. ⁶³Zn-zinc citrate was well tolerated in human participants with no adverse events monitored. Tissues of highest uptake were liver, pancreas, and kidney, with moderate uptake being seen in intestines, prostate (in males), thyroid, spleen, stomach, pituitary, and salivary glands. Moderate brain uptake was observed, and regional dependencies were observed in ⁶³Zn clearance kinetics in relationship with regions of high amyloid-β plaque burden (¹¹C-PiB) and ¹⁸F-FDG hypometabolism. In conclusion, zinc transport was successfully imaged in human participants using the PET probe ⁶³Zn-zinc citrate. Primary sites of uptake in the digestive system accent the role of zinc in gastrointestinal function. Preliminary information on zinc kinetics in patients with AD evidenced regional differences in clearance rates in correspondence with regional amyloid-β pathology, warranting further imaging studies of zinc homeostasis in patients with AD.

Performance of a ⁶²Zn/⁶²Cu microgenerator in kit-based synthesis and delivery of [⁶²Cu]Cu-ETS for PET perfusion imaging

The performance of a commercially produced (62)Zn/(62)Cu microgenerator system, and an associated kit-based radiopharmaceutical synthesis method, was evaluated for clinical site production of [(62)Cu]Cu-ETS (ethylglyoxal bis(thiosemicarbazonato)copper(II)), an investigational agent for PET perfusion imaging. Using 37 generators, containing 1.84±0.23 GBq (62)Zn at 9:00 AM on the day of clinical use, a total of 45 patient doses of [(62)Cu]Cu-ETS (672±172 MBq) were delivered without difficulty. (62)Cu elution yields were high (approximately 90%), accompanied by extremely low (62)Zn breakthrough (<0.001%). Radiopharmaceutical preparation, from the start-of-elution to time-of-injection, consumed less than five minutes. The (62)Zn/(62)Cu microgenerator was a dependable source of short-lived positron-emitting (62)Cu, and the kit-based synthesis proved to be rapid, robust, and highly reliable for "on-demand" delivery of [(62)Cu]Cu-ETS for PET perfusion imaging.

New best estimates for radionuclide solid-liquid distribution coefficients in soils. Part 3: miscellany of radionuclides (Cd, Co, Ni, Zn, I, Se, Sb, Pu, Am, and others)

New best estimates for the solid-liquid distribution coefficient (K(d)) for a set of radionuclides are proposed, based on a selective data search and subsequent calculation of geometric means. The K(d) best estimates are calculated for soils grouped according to the texture and organic matter content. For a limited number of radionuclides this is extended to consider soil cofactors affecting soil-radionuclide interaction, such as pH, organic matter content, and radionuclide chemical speciation. Correlations between main soil properties and radionuclide K(d) are examined to complete the information derived from the best estimates with a rough prediction of K(d) based on soil parameters. Although there are still gaps for many radionuclides, new data from recent studies improve the calculation of K(d) best estimates for a number of radionuclides, such as selenium, antimony, and iodine.

Use of activated carbon in removal of some radioisotopes from their waste solutions

Removal of some radioisotopes namely (152+154)Eu and (65)Zn from radioactive solutions by activated carbon using both batch and column techniques has been performed. Experimental studies were conducted to evaluate and optimize the various process variables, i.e., equilibrium time, carbon dose, solution pH. Sorption data have been interpreted in terms of both Freündlich and Langmuir isotherms. The fixed-bed results indicate the high capacity of the activated carbon for the removal of europium and zinc ions. The data suggest the possible use of activated carbon for the removal of these cations from radioactive waste solutions.

Excitation function measurements and integral yields estimation for natZnp,x reactions at low energies

Excitation functions have been measured for a number of proton-induced nuclear reactions on natural zinc in the energy range from 27.5 MeV down to their threshold energy, using the activation method on stacked foils. Excitation functions and thick target yield for the reactions leading to the formation of (67)Ga,(66)Ga,(68)Ga,(62)Zn and (65)Zn are presented and compared with earlier reported experimental data. The experimental cross-sections and the production yields are tabulated; the excitation functions and the thick target yield curves are plotted in graphs.

Modeling the Metal Center of Cys4 Zinc Proteins

We present here a 67Zn solid-state NMR investigation of several model complexes of zinc coordinated by four sulfurs. The lineshapes were obtained at a variety of magnetic fields from 11.7 T (500 MHz for 1H) to 21.15 T (900 MHz for 1H) and at ambient temperature down to 10 K. The quadrupole coupling constants, Cq's, ranged from 3.25 to 16.7 MHz throughout the series, while the average bond distances only spanned 2.34-2.36 A. Reasonable agreement with experiment was achieved in the molecular orbital calculations using DFT methods and the local density approximation to predict electric field gradients.

Native proteomic analysis of protein complexes in murine intestinal brush border membranes

Intestinal epithelial cell protrusions referred as microvilli or brush border membranes (BBMs) are specialized in the digestion, uptake, and transport of nutrients, trace elements and vitamins from intestinal lumen into the circulation. Disorders of intestinal absorption are common in human pathology and include serious defects such as malabsorption. A detailed description of native digestive protein complexes in BBMs is therefore essential for understanding the physiology and pathology of digestion and absorption. In this study, we employed blue native PAGE (BN-PAGE) technique to separate protein complexes from purified mouse intestinal BBMs. We found 23 distinct protein complexes, which were cut off from the gel, and their protein composition was determined by LC-MS/MS. A total of 55 individual proteins were identified including peptidases, enzymes of carbohydrate metabolism, membrane transporters, cytoskeletal proteins, chaperones, and regulatory enzymes. From the identified proteins, 50% represent molecules with at least one predicted transmembrane domain as predicted by SOSUI software. To the best of our knowledge, this work is the first attempt aimed to characterize the native membrane proteome of intestinal BBM. As demonstrated here, BN-PAGE is a powerful tool for the separation of not only mitochondrial, but also membrane hydrophobic proteins in general. In addition, BN-PAGE technique preserves metal-protein interactions, as shown by the presence of 65Zn in metalloprotein complexes, isolated from zinc-radiolabeled BBMs.

Activity measurements and determination of gamma-ray emission intensities in the decay of 65Zn

An International EUROMET exercise, Action 721, was organized with the objective of obtaining more reliable decay data on the disintegration of 65Zn. Nine laboratories participated, sending their results relating to activity measurements and 1115-keV gamma-ray emission intensity. Participants mainly used the 4pibeta-gamma coincidence method for the activity measurement, the resulting values and uncertainty budgets are described. New gamma-ray emission intensities were also measured in this exercise and, taking into account previously published values, the intensity of the 1115-keV gamma-ray emission has been determined to be 50.22(11)%.

Absolute activity measurement of the electron-capture-based radionuclides 139Ce, 125I, 192Ir and 65Zn by liquid scintillation coincidence counting

Four radionuclides with electron-capture-based decay schemes have been directly measured by a liquid scintillation coincidence extrapolation technique. 125I, 192Ir and 65Zn were measured as part of international key comparisons held under the auspices of the International Bureau of Weights and Measures (BIPM). The 139Ce measurements formed part of a regional comparison organized by the Asia Pacific Metrology Programme (APMP). Since 139Ce decays purely by electron-capture, the basic method is described for this radionuclide. Results and difficulties encountered are discussed and uncertainty budgets are presented.

The LSC efficiency for low-Z electron-capture nuclides

In this paper, we apply the CIEMAT/NIST method to the three low-Z electron-capture nuclides 54Mn, 55Fe and 65Zn by using the KLM and KL1L2L3M atomic rearrangement models, respectively. The counting efficiencies are computed with the new code EMILIA, which comprises an improved model for the interaction of low-energy X-rays with the scintillation cocktail. The calculated counting efficiencies are compared with experimental results.

Standardization and nuclear decay data of 65Zn

Standardization by means of 4pibeta-gamma coincidence counting was applied to calibrate a 65Zn solution within the scope of EUROMET project no. 721. The activity result was combined with gamma-ray spectrometry measurements to investigate the photon emission probabilities. The half-life of 65Zn was measured with improved accuracy by means of 4pi ionization chamber measuring systems that were also used for secondary activity determination. In addition, we tested a new secondary standardization procedure by means of liquid scintillation counting.

Experimental verification of the half-life of 65Zn

The half-life of 65Zn was determined experimentally and compared with literature values. Two ampoules of a 65Zn solution were measured at regular intervals in two ionisation chambers over a period corresponding to nearly two half-lives. The result of 243.8+/-0.3 days is in agreement with the value of 244.0+/-0.2 days obtained by De Roost et al. (Z. Phys. 250 (1975) 395) at the same institute (previously called CBNM) in 1972. Moreover, this half-life is supported by most of the other measurements reported in the literature.

Determination of half-life and photon emission probabilities of (65)Zn

A (65) Zn radioactive solution standardized by an absolute measurement method at Laboratoire National Henri Becquerel (LNHB), was sent to Bureau International des Poids et Mesures (BIPM), in order to include the results in their database. The activity value determined at BIPM was in good agreement with that stated by LNHB (the difference was 0.3%). Additional measurements of (65) Zn activity and half-life were also carried out, by using a 4pigamma ionization chamber; the half-life value proposed by this work: 244.15 (10) days, is consistent to others reported in the literature. The spectra analysis was performed by gamma-ray spectrometry with high-purity germanium detectors, with the aim to improve the accuracy of the photon emission probabilities values of this nuclide. The determined photon emission probabilities are 0.498 for the 1115 ke V gamma-ray, 0.347 and 0.0479 for the X-rays Cu-K(alpha) and Cu-K(beta); the associated uncertainties are 0.4%, 0.9% and 1.1%, respectively.

A study on transfer factors of 60Co and 65Zn from soil to plants in the tropical environment of Bangladesh

Soil to plant transfer factor (TF) of 60Co and 65Zn was determined from radioisotope experiments on plants grown in pots under outdoor ambient tropical conditions for three growing seasons (1995-1998). The TFs were obtained for different plants/crops such as, rice, bean, peanuts pineapple, cabbage, tomato, spinach and grass. The average TF values of 60Co are found to be 0.087. 0.15, 0.12, 0.67, 0.28, 0.79, 1.03 and 0.34 respectively for the above mentioned plants/crops. In case of 65Zn, the average TF values are found to be 2.24, 1.17. 0.89, 1.09, 0.78, 1.34, 2.92 and 1.78, respectively, for the above mentioned plants/crops. The data will be useful to assess the radiation exposure to man associated with the releases of radionuclides from nuclear facilities by means of radiological assessment models that require transfer factors as input parameters to predict the contamination of radionuclides in foodchain.