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The paper discusses a photoactivation method for determining the activity of the long-lived isotope Ca relative to the activity of Co in irradiated reactor biological shielding concrete. It is proposed to use photonuclear reactions on cobalt and calcium isotopes: Co( , ) Co, Ca( , ) K, or Ca( , ) Ca Sc to determine the activity of Ca. The sensitivity of the proposed method is on the order of Bq/g, provided that semiconductor spectrometers with an ultrapure germanium detector are used. The structure and chemical compositions of the sample do not affect the proposed method. It avoids the long sample preparation times associated with radiochemical methods. [ABSTRACT FROM AUTHOR]

The decontamination properties of shampoos for cesium, strontium, and cobalt were determined. The method has been developed for determining the decontaminating properties of shampoos. The chemical part of the study includes the preparation of hair, which consists of forced pollution and subsequent washing. Stable isotopes were used in the work. This has increased the safety of staff during chemical hair research. The analytical part includes the quantitative determination of the cesium, strontium, and cobalt in the hair, which was carried out by the Particle-Induced X-ray Emission (PIXE) method using the analytical nuclear-physical complex “Sokol”. Various shampoos were analyzed, and their decontamination properties were determined. During the research, various samples of shampoos, which are presented on the market of Ukraine, were considered. It has been established that TM “Ringo” shampoo has the best deactivating properties for cesium (Kd - 574.0) and insignificant deactivating properties for strontium (Kd - 3.1) and cobalt (Kd - 3.6). It was determined that with multi-isotope contamination (a mixture of cesium, strontium, and cobalt isotopes) decrease in the deactivation coefficient for all isotopes was observed, which is due to the competition factor of the isotopes in the complexation process with shampoo. Reduction of decontaminating properties was observed on all samples of shampoos. [ABSTRACT FROM AUTHOR]

Another radionuclide of great interest is the PET radionuclide zirconium-89 ( SP 89 sp Zr) and the increased interest in immunoPET imaging probes for preclinical and clinical studies has led to a rising demand for this radionuclide. The work by Da Silva et al. [[18]] has been dedicated to developing new biomedical cyclotron irradiation and radiochemical isolation methods to produce SP 165 sp Er suitable for targeted radionuclide therapeutic studies and characterize a new agent targeting prostate-specific membrane antigen. The field of radiopharmaceuticals is constantly evolving thanks to the great contribution of specialists coming from different disciplines such as inorganic chemistry, radiochemistry, organic and biochemistry, pharmacology, nuclear medicine, physics, etc. 30304795 12 Borgna F., Ballan M., Favaretto C., Verona M., Tosato M., Caeran M., Corradetti S., Andrighetto A., Di Marco V., Marzaro G. Early Evaluation of Copper Radioisotope Production at ISOLPHARM. [Extracted from the article]

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The incorporation of marble particles into the framework of composite material through the polymerization of acrylic acid (AA) and acrylamide acid (AM) using induced gamma irradiation was performed. The novel poly[AA-AM]-marble composite was characterized by multiple analytical instruments such as: energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) analysis, differential thermal analysis-thermogravimetric analysis (DTA-TGA), Fourier transformer infrared (FTIR), surface area measurements using Brunauer–Emmett–Teller (BET) method and scanning electron microscope (SEM). Radioisotopes of fission (152+154Eu) and activation products (60Co) are the major environmental threats. Sorption of stable isotopes of cobalt and europium onto the synthesized composite material as the sorbent is applied. Sorption kinetics of Eu3+ and Co2+ were computed. The obtained results were analyzed by pseudo-first- and second-order, intraparticle diffusion, and Elovich kinetic models. It is deduced that the pseudo-second-order was more fitted and a chemisorption mechanism was suggested. The sorption capacity for Eu3+ and Co2+ on the prepared composite material was measured at the contact time (2 h) and pH = 4 (for Eu3+), pH = 6 (for Co2+) and it was found to be 91.2 and 13.1 mg/g, respectively. A promising result for the decontamination of both Eu and Co ions was obtained in various aquatic ecosystem applications such as: river water, tap water and groundwater. [ABSTRACT FROM AUTHOR]

Aflatoxins are natural mycotoxins that mainly occur in areas with humid climates. One of the methods for the successful elimination of aflatoxins is gamma radiation treatment. In this paper, gamma radiation's influence on the content of aflatoxins in hemp flour and microbiological properties (total number of microorganisms, molds, and potentially pathogenic bacteria) and nutritional values were investigated. The artificial radioactive isotope of cobalt Co‐60, with a dose rate of 10 kGy/hr, was used as the radiation source. Using high‐performance liquid chromatography, we determined that a dose of 4 kGy was sufficient to eliminate aflatoxins below the acceptable value. An irradiation dose of 8 kGy was sufficient to eliminate the total number of microorganisms and molds. Also, a treatment of 3 kGy is enough to remove all bacteria. Finally, it was shown that gamma irradiation does not affect the nutritional value of the product. Novelty Impact Statement: Hemp flour is rich in healthy fats, magnesium, fiber, and protein. However, it may be contaminated with aflatoxins, microorganisms, molds, and potentially pathogenic bacteria. Gamma irradiation is an effective method of food preservation that guarantees food decontamination and protection of nutrients. In this paper, an adequate dose of gamma radiation to preserve hemp flour has been established. [ABSTRACT FROM AUTHOR]

Simultaneous removal of radiocobalt and manganese by adsorption onto polyacrylonitrile/hexadecyltrimethylammonium bromide/potassium copper hexacyanoferrate (PAN/HDTMA/KCuHCF) composite was studied. The synthesized composite was characterized by Fourier-transformed infrared (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The influence of the solution pH was studied in the range 1.5–7.8 and the results showed the effectiveness of the synthesized composite for simultaneous adsorption of radiocobalt and manganese in the pH range 2.5–6 at an adsorbent mass of 4 g/L. Adsorption kinetic data of manganese at the studied concentrations were best fitted by pseudo-second-order kinetic model and the diffusion study showed that the adsorption process was controlled by film diffusion. Thermodynamic parameters (ΔGo, ΔHo and ΔSo) were estimated and the results indicated that adsorption processes of the concerned (radio)toxicants were spontaneous and endothermic in nature. Of the studied isotherm models, Freundlich and Langmuir were the best ones for describing the adsorption isotherm data of radiocobalt and manganese, respectively. The adsorption capacity of PAN/HDTMA/KCuHCF was found to be 23.629 (for radiocobalt) and 62.854 (for manganese). Desorption of Radiocobalt and manganese loaded onto PAN/HDTMA/KCuHCF composite was studied using various desorbing agents at different concentrations. [ABSTRACT FROM AUTHOR]

Cesium and cobalt radioactive isotopes (134Cs and 60Co) are dangerous to human health due to their long half-life about 2.1 and 5.3 year, respectively. Developing a new composite used as an efficient sorbent for these is an urgent requirement for radioactive waste management. Herein, preparation of different materials such as aluminum silicate (AS), cultured of Chlorella vulgaris (NCV) alga, and aluminum silicate/Chlorella vulgaris (AS/NCV) composite 3:1 were prepared by wet chemical technique and used to remove the 134Cs and 60Co radionuclides. Different analytical techniques were used to characterize the prepared sorbents as SEM, TEM, XRD, BET, TGA/DTA, FTIR particle size analyzer, and pore size distribution. The factors affecting the sorption process as pH, temperature, contact time, and weight of adsorbent were studied. The sorption process was found to follow a pseudo-second-order mechanism. The monolayer capacity for 134Cs radionuclide onto the aluminum silicate, non-living Chlorella vulgaris biomass, and aluminum silicate/Chlorella vulgaris composites are 66.67, 83.54, and 90.11 mg/g, respectively, and for 60Co radionuclide are 59.31, 91.99, and 99.24 mg/g, respectively. The values of thermodynamic parameters indicate that the sorption process is endothermic and spontaneous. [ABSTRACT FROM AUTHOR]

Electronic transition spectrum of cobalt monoboride (CoB) in the visible region between 495 and 560 nm has been observed and analyzed using laser-induced fluorescence spectroscopy. CoB molecule was produced by the reaction of laser-ablated cobalt atom and diborane (B2H6) seeded in argon. Fifteen vibrational bands with resolved rotational structure have been recorded, which included transitions of both Co10B and Co11B isotopic species. Our analysis showed that the observed transition bands are ΔΩ = 0 transitions with Ω″ = 2 and Ω″ = 3 lower states. Four transition systems have been assigned, namely, the [18.1]3Π2-X3Δ2, the [18.3]3[uppercase_phi_synonym]3-X3Δ3, the [18.6]3- X3Δ3, and the [19.0]2-X3Δ2 systems. The bond length, ro, of the X 3Δ3 state of CoB is determined to be 1.705 Å. The observed rotational lines showed unresolved hyperfine structure arising from the nuclei, which conforms to the Hund's case (aβ) coupling scheme. This work represents the first experimental investigation of the CoB spectrum. [ABSTRACT FROM AUTHOR]

A synergistic approach involving theory and experiment has been used to study the structure and properties of neutral and negatively charged cobalt-coronene [Com(coronene)] complexes. The calculations are based on density functional theory with generalized gradient approximation for exchange and correlation potential, while the experiments are carried out using photoelectron spectroscopy of mass selected anions. The authors show that the geometries of neutral and anionic Co(coronene) and Co2(coronene) are different from those of the corresponding iron-coronene complexes and that both the Co atom and the dimer prefer to occupy η2-bridge binding sites. However, the magnetic coupling between the Co atoms remains ferromagnetic as it is between iron atoms supported on a coronene molecule. The accuracy of the theoretical results is established by comparing the calculated vertical detachment energies, and adiabatic electron affinities with their experimental data. [ABSTRACT FROM AUTHOR]

The flux-weighted average cross-sections for the 59Co(γ , xn)58-55Co reactions have been measured with the bremsstrahlung end-point energies of 65 and 75 MeV by using the activation method in combination with the off-line γ -ray spectrometry. The measured cross-sections for the (γ , n) , (γ , 2 n) , (γ , 3 n) and (γ , 4 n) reactions of 59Co at 65 MeV are 15. 828 ± 0. 491 , 5. 003 ± 0. 206 , 0. 408 ± 0. 047 and 0. 039 ± 0. 008 mb, whereas at 75 MeV are 15. 653 ± 0. 361 , 4.965±0.289, 0. 389 ± 0. 062 and 0. 036 ± 0. 007 mb, respectively. The 59Co(γ , xn) reaction cross-sections as a function of photon energy were also theoretically simulated by using TALYS 1.9 code. Then the flux-weighted average cross-sections at different bremsstrahlung energies were obtained from the theoretical values and the literature data at lower energy based on mono-energetic photons. The present data are measured for the first time and are found to be in good agreement with the theoretical flux-weighted average values. It was found that the 59Co(γ , xn)58-55Co reaction cross-sections increase from their threshold values to a certain bremsstrahlung energy. After a certain energy, the individual 59Co(γ , xn) reaction cross-sections decrease with the increase of bremsstrahlung energy due to opening of other reaction channels. These two observations indicate the role of excitation energy and its partition in different reaction channels. All the four cobalt isotopes produced from the 59Co(γ , xn) reactions have medical and other applications. [ABSTRACT FROM AUTHOR]

Tara‐decorated terpyridines 1–3 and their 1:2 Co2+ [Co(L)2](ClO4)2 (L = 1–3) and Co3+ complexes [Co(L)2](ClO4)2(SbCl6) (L = 1,3) are reported. The solid‐state complex metrics of [Co(3)2]2+ and [Co(1)2]3+ indicate an assignment as spin‐quartet Co2+ or spin‐singlet Co3+, which is in accord with DFT and 1H NMR studies. Vis‐NIR spectra of 1[Co3+(L)2]3+ show characteristic Tara→Co3+ charge‐transfer bands, giving no direct indication of L‐based oxidation events, irrespective of the solvent. Theoretical studies reveal no charge transfer induced spin transition in [Co3+(L)2]3+, although a substantial decrease of the HOMO‐LUMO gap prevails in [Co3+(1)2]3+ as compared with [Co(tpy)2]3+. The destabilisation of the HOMO is not sufficient to allow an equilibration among closed‐ and open‐shell formulations. The computed singlet‐triplet and singlet‐quintet splitting in [Co(1)2]3+ renders these open‐shell formulations to reside only moderately above the ground state. Design criteria are derived from this analysis aiming at a further stabilisation of the open‐shell species through implementation of more strongly electron releasing Tara substituents. Co3+ complexes containing triarylamine‐substituted polypyridyl ligands evince smaller HOMO‐LUMO gaps than the parent 2,2′:6′,2′′‐terpyridine congener. Extended DFT calculations revealed high‐lying triarylamine‐borne donor levels within the examined complexes. The energies of the LUMOs are unaffiliated to the ligand topology. [ABSTRACT FROM AUTHOR]

In this study, novel surface-modified hematite nanoparticles (α-Fe2O3 NPs) were prepared at 250 °C using iron(III) chloride hexahydrate (FeCl3·6H2O) and oleic acid (C18H34O2) as raw materials for the removal of cobalt-60 radiocations from aqueous solutions by hydrothermal method. α-Fe2O3 NPs were characterized by X-ray diffraction, Fourier transform infrared (FT-IR), scanning electron microscope, transmission electron microscopy and Brunauer-Emmett-Teller. According to the results, the average diameter and length of the synthesized α-Fe2O3 nanorods varied in the range of 30-60 and 400-700 nm, respectively, when the specific surface area was 31.29 m2/g. In batch experiments, the effect of some variables such as pH (2-10), adsorbent weight (0.5, 1, 1.5, 2.5, 3.75 and 5 mg in 25 mL solution), initial concentration of cobalt-60 radiocations (1, 10, 25, 50, 75 and 100 mg/L), temperature (25, 30, 35, 40 and 45 °C) and contact time (1, 2, 3, 4, 5 and 6 h) was investigated at 120 rpm. The optimized condition for cobalt-60 adsorption onto α-Fe2O3 NPs was obtained in pH 6.5, initial radiocation concentration of 1 mg/L, contact time of 2 h and nano-α-Fe2O3 sorbent concentration of 20 mg/L. On the other hand, the results indicated that adsorption of cobalt-60 onto the synthesized nano-α-Fe2O3 well fitted the Ho model as linear pseudo-second-order kinetics. In contrast, analysis of equilibrium data showed that the Redlich-Peterson isotherm model was suitable for describing cobalt-60 adsorption onto α-Fe2O3 NPs and the maximum uptake capacity was about 142.86 mg/g at 25 ± 1 °C according to Langmuir isotherm results. Meanwhile, the actual maximum adsorption capacity was about 99 mg/g. Therefore, it can be concluded that the synthesized novel surface-modified α-Fe2O3 NPs is an environment-friendly and a promising adsorbent for the removal of cobalt-60 radiocations from aqueous solutions. [ABSTRACT FROM AUTHOR]

The amount of data corruption in a wide assortment of flash memories observed during Co-60 total dose tests is shown to have a strong dependence on the direction in which the Co-60 irradiation is performed. The effect is due to dose enhancement from the metal layers above the floating gate. The dose enhancement effect is shown to become greater as technology node scales and is even observed in on a state-of-the-art 3-D NAND flash memory. The radiation hardness assurance implications of this dose enhancement effect are significant and are discussed in detail. [ABSTRACT FROM AUTHOR]

The first results of Mössbauer spectroscopy measurements of the distribution of the amplitude of mechanical vibrations of a 25-μm-thick stainless steel foil along its surface are presented. The gamma radiation of 57Co with a wavelength of 86 pm has been used for the measurements. Sample vibrations along the direction of gamma radiation propagation have been induced using a polymer piezoelectric transducer. At moderate applied voltages, the measured oscillation amplitude does not exceed 50 pm. The measurement accuracy of the vibration-amplitude distribution along the foil surface is 3-6 pm. This method is proposed to create standards of mechanical displacements that can be used to calibrate tunneling microscopes. [ABSTRACT FROM AUTHOR]

The development of the nuclear industry is accompanied by the inevitable formation of radioactive waste that creates a substantial risk of environmental pollution. In the present work, an effective Ca-Mg phosphate sorbents were prepared using dolomite as an inexpensive raw material. It was established that the removal of 60Co is predominantly determined by the salinity and pH value of aqueous solution. The highest sorption efficiency was shown for PD-2 sorbent with Kd(60Co) changing from 2.44 × 104 to 3.32 × 103 mL g−1 in the salinity range of 0-50 g L−1. The produced materials are promising for seawater and liquid radioactive waste treatment from 60Co radionuclide. [ABSTRACT FROM AUTHOR]

Studies the changes in the absorption spectra induced by Co60 irradiation and temperature annealing for selected PbWO4 crystals. Shaping of the absorption spectrum by four color centers; Thermoluminescence (TSL) glow curves above room temperature; Determination of trap levels resulting from irradiation; Correlation between results obtained by TSL and Co60 irradiation induced absorption changes.

An efficient adsorbent, reduced graphene oxide-polyaniline (rGO-PANI) nanocomposite was used for solid phase extraction and pre-concentration of ultra-trace levels of Co2+ in different real samples. Graphene oxide (GO) was synthesised from graphite by Hummer method and after reduction by NaBH4, it was modified with poly-aniline to produce rGO-PANI. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and electron-dispersive X-ray spectroscopy (EDS) were used for characterisation of the synthesised rGO-PANI nanocomposite. The main parameters affecting the extraction efficiency such as pH, amounts of adsorbent, extraction and desorption times were optimised by response surface methodology based on central composite design (RSM-CCD). According to the results, pH 8, 5.8 mg rGO-PANI, 15 min extraction time and 8 min desorption time were selected as the optimum values. Under the optimum conditions, the calibration curve was linear in the range of 0.05-0.6 µg L−1 for Co2+. The relative standard deviation (%RSD) for seven replicate analysis of 0.2 µg L−1 Co2+ was 3.2% and the limit of detection (LOD) was 0.017 µg L−1 Co2+ (n = 7). The certified reference material, CRM-TMDW, was successfully used to validate the accuracy of the proposed method and finally, this technique was applied for determination of ultra-trace levels of Co2+ in different water and food samples. [ABSTRACT FROM AUTHOR]

To investigate the influence of chemical pressure on the eg orbital occupation and the spin state of Co3+ ions, which are closely related to electrochemical reaction of catalysts for energy storage applications, we have prepared a new material Sr1.7Ca0.3CoO3F, which was previously predicted to possess an intermediate‐spin (IS) state with eg1 configuration. Our experimental Co‐L2,3 X‐ray absorption spectrum of Sr1.7Ca0.3CoO3F was very similar to those of the high‐spin (HS) Co3+ references Sr2CoO3F and Sr2CoO3Cl indicating an HS Co3+ ground state. The HS‐Co3+ ground state in Sr1.7Ca0.3CoO3F was further confirmed by using O‐K XAS spectra and theoretical simulation of the Co‐L2,3 XAS spectra with configuration‐interaction cluster calculations. We present theoretical energy diagrams of three spin states for Co3+ ions in Sr2CoO3F as a function of external pressure based on the crystal structures observed in a previous high‐pressure study. We have also investigated the structural conditions that are required to stabilize the IS state in this effective local pyramidal structure theoretically, and found that the in‐plane Co–O distance (<1.88 Å) and the out‐of‐plane Co displacement (<0.18 Å) are critical conditions for obtaining the IS‐Co3+ ground state. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis and structural characterization of the hitherto unknown parent Co(bz)2+ (bz=benzene) complex and several of its derivatives are described. Their synthesis starts either from a CoCO5+ salt, or directly from Co2(CO)8 and a Ag+ salt. Stability and solubility of these complexes was achieved by using the weakly coordinating anions (WCAs) [Al(ORF)4]− and [F{Al(ORF)3}2]− {RF=C(CF3)3} and the solvent ortho‐difluorobenzene (o‐DFB). The magnetic properties of Co(bz)2+ were measured and compared in the condensed and gas phases. The weakly bound Co(o‐dfb)2+ salts are of particular interest for the preparation of further CoI salts, for example, the structurally characterized low‐coordinate 12 valence electron Co(PtBu3)2+ and Co(NHC)2+ salts. [ABSTRACT FROM AUTHOR]

Four cobalt coordination polymers, namely, {[Co(3-pmpmd)Cl2]·2.6CH3OH}n (1), {[Co2(3-pmpmd)4(NCS)4]·2CH3OH·5CHCl3}n (2), {[Co(3-pmpmd)1.5(NO3)2]·0.8CH3OH}n (3) and {[Co(3-pmpmd)2(NCS)2]·CHCl3}n (4) (3-pmpmd = N,N′-bis(3-pyridylmethyl)pyromellitic diimide) have been synthesized and characterized. The different conformations of the diimide ligand are crucial for obtaining structural diversity. The adsorption isotherms of complex 3 for water and ethanol are quite different; 3 adsorbs water with a gate-opening phenomenon, but it does not adsorb ethanol and therefore, it has the potential capacity to capture water from ethanol. [ABSTRACT FROM AUTHOR]

Two penta-coordinate Co2+ complexes, namely [Co(PDA)(H2O)2] (1) and [Co(PDA)(1,2-BIYB)0.5(H2O)]·(H2O) (2), (H2PDA = pyridine-3,5-dicarboxylate, 1,2-BIYB = 1,2-bis(imidazol-1-ylmethyl) benzene), which have similar ligand fields except for their local symmetries due to the different coordination atoms of Co2+, were synthesized, structurally analyzed, and magnetically investigated. Complexes 1 and 2 possess 3D supramolecular structures in which the 2D structures are further cross-linked by hydrogen bonds. Complex 1 can be observed to transform into 2 in the presence of 1,2-BIYB coligand, and 1 and 2 have distortion trigonal bipyramid geometries when the space group of Co2+ ion changes from C2/c in 1 to P2(1)/c in 2. Meanwhile, the average equatorial Co–O/N bond distances of CP 1 (2.1655 Å) are clearly larger than its axial Co–O bond distances (2.0704 Å); for CP 2, the average equatorial Co–O/N bond distances (2.0814 Å) are slightly shorter than the axial Co–O/N bond distances (2.0896 Å), which leads to different axial compression and distortion of the trigonal bipyramid metal environment. Fine-tuning of the structures arising from the auxiliary ligands has a definite impact on the magnetic properties of compounds 1 and 2. Both compounds share easy-plane magnetic anisotropies of their central Co2+ ions (D = 16 cm−1 for 1 and D = 59 cm−1 for 2) and different slow magnetic relaxations of magnetization with applied magnetic fields of 1500 Oe and 3000 Oe, respectively. [ABSTRACT FROM AUTHOR]

Two new three-dimensional (3D) Co(II)- and Cu(II)-azido frameworks, [Co2(N3)4(bpym)2]n (1) and [Co2(N3)4(bpym)]n (2), were successfully synthesized by introducing a semi-flexible N-donor ligand, 5,5'-bipyrimidin (bpym), with different bridging modes and orientations. Compounds 1 and 2 were structurally characterized by X-ray crystallography, IR spectroscopy, thermogravimetry and elemental analysis. Compounds 1 and 2 are 3D pillared-layer frameworks with double end-on (EO) azido bridged dinuclear motifs, [M2(EO-N3)2]. In Compound 1, the bpym ligands show trans μ2-bridging mode and the role as pillars to connect the Co(II)-azido layers, composed of [Co2(EO-N3)2] motifs and single end-to-end (EE) azido bridges, to a 3D network with BN topology. In contrast, in 2, the bpym ligand adopts a twisted μ4-bridging mode, which not only connects the adjacent [Cu2(EO-N3)2] units to a layer, but also functions as a pillar for the layers of the 3D structure. The structural diversities between the two types of architectures can be attributed to the coordination geometry preference of the metal ions (octahedral for Co2+ and square pyramidal for Cu2+). Magnetic investigations revealed that Compound 1 exhibits ferromagnetic-like magnetic ordering due to spin canting with a critical temperature, TC = 33.0 K, and furthers the field-induced magnetic transitions of metamagnetism at temperatures below TC. Compound 2 shows an antiferromagnetic ordering with TN = 3.05 K and a field-induced magnetic transition of spin-flop at temperatures below the TN. [ABSTRACT FROM AUTHOR]

We show that use of the radionuclide 56Co for calibration of the full energy peak efficiency, ε, of a coaxial HPGe detector, in addition to the commonly employed set of activity standards (133Ba, 241Am, 152Eu, 57Co, 137Cs, 88Y, 65Zn), affects significantly the ε values in the high energy region. This change resulted in substantial improvement of the accuracy of Ca determination by k0-INAA via the 49Ca radionuclide, which emits predominantly the 3084 keV photons, as demonstrated by Ca results in NIST SRMs 1547 Peach Leaves, 1633b constituent elements in coal fly ash, and 2711 Montana II Soil. [ABSTRACT FROM AUTHOR]

In this work, we irradiated a high-definition (HD) industrial camera based on a commercial-off-the-shelf (COTS) CMOS image sensor (CIS) with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR) versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB). The work is valuable and can provide suggestion for camera users in the radiation field. [ABSTRACT FROM AUTHOR]

Existing remote radioactive contamination depth estimation methods for buried radioactive wastes are either limited to less than 2 cm or are based on empirical models that require foreknowledge of the maximum penetrable depth of the contamination. These severely limits their usefulness in some real life subsurface contamination scenarios. Therefore, this work presents a novel remote depth estimation method that is based on an approximate three-dimensional linear attenuation model that exploits the benefits of using multiple measurements obtained from the surface of the material in which the contamination is buried using a radiation detector. Simulation results showed that the proposed method is able to detect the depth of caesium-137 and cobalt-60 contamination buried up to 40 cm in both sand and concrete. Furthermore, results from experiments show that the method is able to detect the depth of caesium-137 contamination buried up to 12 cm in sand. The lower maximum depth recorded in the experiment is due to limitations in the detector and the low activity of the caesium-137 source used. Nevertheless, both results demonstrate the superior capability of the proposed method compared to existing methods. [ABSTRACT FROM AUTHOR]

Abstract: Visible‐light capture activates a thermodynamically inert CoIII−CF3 bond for direct C−H trifluoromethylation of arenes and heteroarenes. New trifluoromethylcobalt(III) complexes supported by a redox‐active [OCO] pincer ligand were prepared. Coordinating solvents, such as MeCN, afford green, quasi‐octahedral [(SOCO)CoIII(CF3)(MeCN)2] (2), but in non‐coordinating solvents the complex is red, square pyramidal [(SOCO)CoIII(CF3)(MeCN)] (3). Both are thermally stable, and 2 is stable in light. But exposure of 3 to low‐energy light results in facile homolysis of the CoIII−CF3 bond, releasing .CF3 radical, which is efficiently trapped by TEMPO. or (hetero)arenes. The homolytic aromatic substitution reactions do not require a sacrificial or substrate‐derived oxidant because the CoII by‐product of CoIII−CF3 homolysis produces H2. The photophysical properties of 2 and 3 provide a rationale for the disparate light stability. [ABSTRACT FROM AUTHOR]

A series of metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) complexes with the azodye ligand derived from the 4-methyl-2-aminopyridine and β-napthol have been synthesised. These complexes and the ligand have been characterised by analytical and spectral techniques such as IR, NMR, electronic and magnetic measurement. The structural compositions of the ligand and complexes have been determined by FAB-MS structural studies. The computational study of studied compounds has been made to determine geometrical parameters and electronic parameters. The experimental data of the compounds are compared with the computationally generated data. The structural activity relationships of all the compounds have been computed to explain their biological properties. [ABSTRACT FROM AUTHOR]

In this study, three-dimensional flower-like α-FeO (F-FeO) microspheres were synthesized by a facile chemical bath method and characterized by XRD, FE-SEM, TEM and BET specific surface area. The maximum sorption capacity of Co(II) on F-FeO reached to 6.78 × 10 mol/g at 298 K and pH 6.5. The pH and ionic strength experiments implied that the removal of F-FeO towards Co(II) is dominated by ion exchange and/or outer-sphere surface complexation at pH < 7.5, and by inner-sphere surface complexation at pH > 7.5. In conclusion, the F-FeO microspheres could be applied as cost-effective materials for the removal of Co(II) from wastewater. [ABSTRACT FROM AUTHOR]

An automatic control system is one of the most important parts of an irradiation facility. The level of this control is always maintained to comply with safety procedures during routine work in this field. Also sometimes it is limited to the minimum level of regulation required due to economical aspects; some commercial systems are generally made by manufacturers of industrial facilities and considered affordable by irradiators. In some cases specific irradiation facilities tailor their control systems to their needs. For this kind of irradiator the control system can be developed and upgraded according to personal and industrial experiences. These upgrading procedures are also used by others to develop their systems. The objective of this paper is to share a local experience in upgrading security, safety systems and the use of cobalt-60 for the irradiator. It is a composite experiment at SIBO INRA/Tangier, Morocco and concerns the: (i) upgrade of cobalt-60 in a temporary pool in the SIBO irradiator in Tangier. This operation was conducted in collaboration with the International Atomic Energy Agency (IAEA) and was a success story of 2014 according to the general conference of IAEA; (ii) safety and technical upgrade of the system in the SIBO irradiator made in collaboration with IAEA; (iii) installation and upgrade of the security system in accordance with the Global Threat Reduction Programme (GTRP) to reduce the threat of a Radiological Dispersal Device (RDD) in collaboration with The United States Department of Energy's National Nuclear Security Administration (NNSA). [ABSTRACT FROM AUTHOR]

Montmorillonite intercalated with mixed alumina-iron (III) oxide pillars and promoted with hexamminecobalt (III) chloride was studied in selective catalytic reduction of NO with NH3. Pillaring process extended the interlayer spacing by 0.236 nm and increased specific surface area (SSABET) from 33m2 up to 299m2. Interlayer space width did not change after calcination process, but high temperature could cause decomposition of hexamminecobalt (III) - [Co(NH3)6]3+, possibly to Co2+. Promotion of hexamminecobalt (III) chloride to pillared clay did not significantly change SSABET. The intercalation process influenced positively selective catalytic reduction activity, but very high formation of N2O was observed. Pillared clay, promoted with [Co(NH3)6]3+, showed higher selective catalytic reduction activity and much lower N2O formation than unpromoted, pillared sample. Clay with interlayer cations exchanged for [Co(NH3)6]3+, without pillaring, showed no selective catalytic reduction activity, but still produced high amounts of N2O. [ABSTRACT FROM AUTHOR]

The new 2-D cobalt(II) coordination polymer with pyrazine was synthesized surprisingly from reaction of CoCl and tetrapyrido[3,2- a:2′,3′- c:3″,2″- h:2‴,3‴ -j]phenazine (tpphz) in methanol as medium and characterized by means of Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy and X-ray single crystal analysis. The results showed that coordination polymer consist of cobalt(II) chain with pyrazine-bridged which crystallizes in orthorhombic unit cell (a = 10.1307, b = 10.1310, c = 10.6838 Å) and space group Pban. Density functional theory (DFT) calculations were also done to figure out the electronic structure of the compound from theoretical aspect. The electronic spectrum of coordination polymer was investigated and the DFT/TDDFT procedures were employed to assign the absorption bands. The thermal decomposition of the title compound resulted in formation of cobalt(II) oxide nanoparticles with average size of 50 nm. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of radiation on the content of animal diet constituents using global metabolomics. Aqueous methanolic extracts of control and cobalt-60-irradiated Teklad 7001 diets were comprehensively analyzed using nano-liquid chromatography-MS/MS. Among the over 2000 ions revealed by XCMS followed by data preprocessing, 94 positive and 143 negative metabolite ions had greater than 1.5-fold changes and p-values <0.01. Use of METABOANALYST statistical software demonstrated complete separation of the irradiated and non-radiated diets in unsupervised principal components analysis and supervised partial least squares discriminant analysis. Irradiation led to an increase in the content of phytochemicals such as glucosinolates and oxidized lipids in the diet. Twenty-eightmetabolites that were significantly changed in the irradiated samples were putatively identified at the level of molecular formulae by MS/MS. MS/MSALL analysis of chloroform-methanol extracts of the irradiated diet showed increased levels of a number of unique linoleic acid-derived branched fatty acid esters of hydroxy fatty acids. These data imply that gamma irradiation of animal diets causes chemical changes to dietary components, which in turn may influence the risk of mammary cancer. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Normally, differentiated thyroid cancer (DTC) tends to be biologically indolent, highly curable and has an excellent prognosis. However, the treatment may fail when the cancer has lost radioiodine avidity. The present study was carried out in order to evaluate the cytotoxic and genotoxic effects of 131I and 60Co and radioiodine uptake in WRO cells, derived from DTC, harboring the BRAFV600E mutation. WRO cells showed a relatively slow cell cycle of 96.3 h with an unstable karyotype containing various double minutes. The genotoxicity assay (micronucleus test) showed a relative high radioresistance to 131I (0.07-3.70 MBq/mL), independent of treatment with recombinant human thyroid-stimulating hormone (rhTSH). For the cytotoxicity assay, WRO cells were also relatively resistant to 60Co (range: 0.2-8.3 Gy), but with a gradual decrease of viability as a function of time for higher doses (20 and 40 Gy, starting from the fifth to sixth day). For internal irradiation with 131I, WRO cells showed a decline in viability at radioactive concentration higher than 1.85 MBq/mL; this was even more effective at 3.70 MBq/mL, but only when preceded by rhTSH, in coincidence with the highest level of 131I uptake. These data show promising results, since the loss of the ability of thyroid cells to concentrate radioiodine is considered to be one of the main factors responsible for the failure of 131I therapy in patients with DTC. The use of tumor-derived cell lines as a model for in vivo tumor requires, however, further investigations and deep evaluation of the corresponding in vivo effects. Environ. Mol. Mutagen. 58:451-461, 2017. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The reaction of CoCl2.6H2O with mixed ligands of 2,2'-oxybis(benzoic acid) (2,2'-H2oba) and trans-1,2-bis(4-pyridyl)ethylene (bpe) under hydrothermal conditions produced a new 3D cobalt(II) supramolecular architecture {[Co(oba)(bpe)(H2O)].1/2bpe}n (1), which was structurally characterized by elemental analysis, infrared spectroscopy, thermogravimetric analyses, and single-crystal X-ray diffraction. The results show that the Co(II) ions are connected to form an infinite polymeric chain by bpe ligands in complex 1. Due to strong intermolecular O-H...O hydrogen bonds, the adjacent chains are connected to generate a double-chain structure. These double chains are joined by O-H...N hydrogen bonding to produce a 2D supramolecular architecture. Furthermore, through intermolecular C-H...O hydrogen bonds, the layers are linked into a 3D supramolecular structure. Magnetic susceptibility measurements have indicated that complex 1 shows weak antiferromagnetic interactions between adjacent Co(II) ions. [ABSTRACT FROM AUTHOR]

The complex formation and extraction of anionic chelates of Co(II)-4-(2-thiazolylazo)resorcinol (TAR) with cations of monotetrazolium salts (TS) - (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and 3-(2-naphthyl)-2,5-diphenyl-2H-tetrazolium chloride (TV) - in the liquid-liquid extraction system Co(II)-TAR-TS-HO-CHCl were studied by spectrophotometric methods. The optimum conditions for the extraction of Co(II) were found. The molar ratio of the components and the form of the anionic chelates of Сo(II) in the extracted compounds were determined by independent methods. The association process in the aqueous phase and the extraction process were investigated and quantitatively characterized. The following key constants were calculated: association constant, distribution constant, extraction constant, and recovery factor. The validity of the Beer's law was checked, and some analytical characteristics were calculated. Based on the obtained results and the lower price of the monotetrazolium salt MTT compared with that of TV, the ion-associated complex of Co(II)-TAR-MTT can be implemented for determination of cobalt(II) traces in alloys and biological, medical, and pharmaceutical samples. [ABSTRACT FROM AUTHOR]

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60Co γ-ray irradiation-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization at room temperature with 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) as the chain transfer agent was first applied to acrylonitrile (AN) polymerization, providing a "green" platform for preparing polyacrylonitrile (PAN)-based carbon fibers using an environment-friendly energy source. Various effects of dose rate, molar ratio of the monomer to the chain transfer agent, monomer concentration and reaction time on the AN polymerization behaviors were performed to improve the controllability of molecular the weight and molecular weight distribution of the obtained PAN. The feature of the controlled polymerization was proven by the first-order kinetics, linear increase of the molecular weight with the monomer conversion and a successful chain-extension experiment. The molecular weight and molecular weight distribution of PAN were characterized by size exclusion chromatography (SEC). ¹H NMR and Matrix assisted laser desorption ionization/time of flight mass spectra (MALDI-TOF-MS) confirmed the chain-end functionality of PAN, which also was supported by the successful chain-extension experiments of original PANs with acrylonitrile and styrene as the second monomers respectively. [ABSTRACT FROM AUTHOR]

The article discusses the development of the atomic energy research project in Chalk River, Ontario. The National Research Council of Canada operates the project including the nuclear rocket experiment (NRX) pile operation, chemical plants, isotope production and chemical control of laboratories. The NRX pile is used to experiment direct application of atomic energy sufficient to produce all radioactive isotopes required for tracer experiments in radio-chemistry. The application of isotopes to scientific research and industrial processes are increasing, and there is a possibility of developing Cobalt 60 sources of 1000 curies or more.

A comparison was made between two computational phantoms, modelled from the unified phantom UPh-08 T, for whole-body counting applications. One of these was further compared with the International Commission on Radiological Protection reference adult male computational phantom. The simulations that were performed for the comparison of all three voxel phantoms use various distributions of 60Co. The two voxel phantoms of the UPh-08 T showed good agreement, despite different methods of phantom modelling. Also, effects on efficiency of the inhomogeneous distribution of a radionuclide in the computational UPh-08 T phantom were studied, using the realistic biodistribution of 140La. The results show that the activity estimation of radionuclides, which are inhomogeneously distributed in the human body, will be in error if a homogeneous distribution is assumed for the calibration of whole-body counting systems. [ABSTRACT FROM AUTHOR]

The authors describe the synthesis of a nanocomposite consisting of graphene oxide, cobalt(III) oxide and horseradish peroxidase (HRP/GO-CoO) in a nafion matrix. The composite, when deposited on a glassy carbon electrode (GCE), is shown to enable electrochemical sensing of HO. The morphology of the nanocomposite was characterized by field emission scanning electron microscopy, X-ray diffraction spectroscopy, energy dispersive X-ray spectroscopy, UV-vis spectroscopy, and FTIR spectroscopy. The response of the modified electrode to HO was examined by cyclic voltammetry and DC potential amperometry at a working potential −0.57 V (vs. Ag/AgCl) at pH 7.0. Features include (a) a sensitivity of −18.7 ± 0.5 μA mM cm, (b) a linear dynamic range from 1 mM to 30 mM, (c) a 2 mM detection limit, and (d) a response time of ~20 s. The performance of the sensor for the routine analysis was investigated by the determination of HO present in hair dye product with appreciable percent recovery value. Moreover, the HRP/GO-CoO-nafion/GCE biosensor exhibited good selectivity towards HO quantification in presence of common interfering species such as glucose, uric acid and ascorbic acid. This good analytical performance makes this biosensor a promising tool for sensing of HO. [ABSTRACT FROM AUTHOR]

Four clays (bentonite, montmorillonite, diatomite and sepiolite) were used as low-cost adsorbents for removal of Co(II) radionuclides. The effect of the solution pH was studied in the range 1.5-10. The kinetic data were analyzed by the pseudo-first-order, the pseudo-second-order and intraparticle diffusion models. The equilibrium isotherms of Co(II) were analyzed by Langmuir and Freundlich models. The thermodynamic parameters (ΔG, ΔH and ΔS) were calculated and the results showed that the present adsorption processes are feasible, spontaneous and endothermic in nature. Desorption experiments of Co(II)-loaded clays suggested that adsorption of Co(II) was governed by physical adsorption and surface complexation. [ABSTRACT FROM AUTHOR]

The phase formation, texture, and photocatalytic activity of synthesized oxide nanocomposites of titanium(IV) and cobalt(II) have been studied in relation to the cobalt content and temperature of heat treatment. The high photocatalytic activity of optimum compositions has been recorded within the spectral range of visible light with λ ≥ 670 nm. [ABSTRACT FROM AUTHOR]

Aim of the study: The 57Co radioisotope has recently been proposed as a hypothetical brachytherapy source due to its high specific activity, appropriate half-life (272 days) and medium energy photons (114.17 keV on average). In this study, Task Group No. 43 dosimetric parameters were calculated and reported for a hypothetical 57Co source. Material and methods: A hypothetical 57Co source was simulated in MCNPX, consisting of an active cylinder with 3.5 mm length and 0.6 mm radius encapsulated in a stainless steel capsule. Three photon energies were utilized (136 keV [10.68%], 122 keV [85.60%], 14 keV [9.16%]) for the 57Co source. Air kerma strength, dose rate constant, radial dose function, anisotropy function, and isodose curves for the source were calculated and compared to the corresponding data for a 192Ir source. Results: The results are presented as tables and figures. Air kerma strength per 1 mCi activity for the 57Co source was 0.46 cGyh–1 cm 2 mCi–1. The dose rate constant for the 57Co source was determined to be 1.215 cGyh–1U–1. The radial dose function for the 57Co source has an increasing trend due to multiple scattering of low energy photons. The anisotropy function for the 57Co source at various distances from the source is more isotropic than the 192Ir source. Conclusions: The 57Co source has advantages over 192Ir due to its lower energy photons, longer half-life, higher dose rate constant and more isotropic anisotropic function. However, the 192Ir source has a higher initial air kerma strength and more uniform radial dose function. These properties make 57Co a suitable source for use in brachytherapy applications. [ABSTRACT FROM AUTHOR]

The study was carried out to investigate the effect of gamma irradiation on storage quality and shelf life of mangoes. Mature green mangoes (local variety, Sindhi) were taken from fruit market and irradiated with Co60 gamma doses of 0.5, 1.0 and 1.5kGy. Samples were stored in refrigerator (4°C) temperature up to three weeks and microbial analysis of both irradiated and non-radiated mangoes was performed weekly by plate enumeration method. The study revealed the presence of Salmonella sonnie, Eschnichia.coli and Pseudomonas species dominating on the fruit surface. Percentage reduction up to 95% was observed at 1kGy ?-radiation dose whereas maximum fungal reduction up to 40% was observed at 1.5kGy. For shelf life extension, 1kGy dose was optimum as it increased the shelf life of mango up to 2 weeks by delaying ripening without causing any damage to fruit as compared to control. [ABSTRACT FROM AUTHOR]

Chitosan-clinoptilolite composite was prepared and tested for removing radiocobalt from aqueous solution. The composite was characterized with Fourier transform infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy coupled with energy dispersive X-ray analysis. The sorption of Co(II) on chitosan-clinoptilolite composite was pH-dependent and ionic strength-independent. The kinetic sorption was fitted well by a pseudo-second-order rate equation. The thermodynamic parameters (Δ H, Δ S, Δ G) revealed that the sorption of Co(II) on chitosan-clinoptilolite composite was spontaneous and endothermic. The study showed that chitosan-clinoptilolite composite had excellent potential for the treatment of wastewater containing radiocobalt. [ABSTRACT FROM AUTHOR]