Advances in the management of radioactive wastes and radionuclide contamination in environmental compartments: a review.

Several anthropogenic activities produce radioactive materials into the environment. According to reports, exposure to high concentrations of radioactive elements such as potassium (40K), uranium (238U and 235U), and thorium (232Th) poses serious health concerns. The scarcity of reviews addressing the occurrence/sources, distribution, and remedial solutions of radioactive contamination in the ecosystems has fueled data collection for this bibliometric survey. In rivers and potable water, reports show that several parts of Europe and Asia have recorded radionuclide concentrations much higher than the permissible level of 1 Bq/L. According to various investigations, activity concentrations of gamma-emitting radioactive elements discovered in soils are higher than the global average crustal values, especially around mining activities. Adsorption technique is the most prevalent remedial method for decontaminating radiochemically polluted sites. However, there is a need to investigate integrated approaches/combination techniques. Although complete radionuclide decontamination utilizing the various technologies is feasible, future research should focus on cost-effectiveness, waste minimization, sustainability, and rapid radionuclide decontamination. Radioactive materials can be harnessed as fuel for nuclear power generation to meet worldwide energy demand. However, proper infrastructure must be put in place to prevent catastrophic disasters.

DFT and CV data of 4-phenyl-substituted dichloro(bis{2-[1-(phenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})iron(II) coordination compounds.

The data presented in this paper are related to the research article entitled "Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R=CH3, OCH3, COOH, F, Cl, CN, H and CF3." (Conradie et al., 2019) [1]. This paper presents electrochemical and density functional theory data of 4-phenyl-substituted dichloro(bis{2-[1-(4-R-phenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})iron(II) compounds, containing differently substituted 2-(1-(4-R-phenyl)-1H-1,2,3-triazol-1-yl)pyridine ligands (L2 - L9) (Tawfiq et al., 2014) [2]. Density functional theory calculated data of five different structural isomers for each compound, consistently show that the title compounds are octahedral and that the isomer with the chloride atoms, the pyridine nitrogens and the triazol nitrogens trans to each other, has the lowest energy. Natural bonding orbital (NBO) data and quantum theory of atoms in molecules (QTAIM) data of dichloro(bis{2-[1-(phenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})iron(II) show origin for the preference of the trans isomer.

Chemical and structural data of (1,2,3-triazol-4-yl)pyridine-containing coordination compounds.

The data presented in this paper are related to the research article entitled "Novel dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})metal(II) coordination compounds of seven transition metals (Mn, Fe, Co, Ni, Cu, Zn and Cd)" (Conradie et al., 2018) [1]. This paper presents characterization and structural data of the 2-(1-(4-methyl-phenyl)-1H-1,2,3-triazol-1-yl)pyridine ligand (L2) (Tawfiq et al., 2014) [2] as well as seven dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})metal(II) coordination compounds, [M(L2)2Cl2], all containing the same ligand but coordinated to different metal ions. The data illustrate the shift in IR, UV/VIS, and NMR (for diamagnetic complexes) peaks when L is coordinated to the metals, as well as the influence of the different metals on the peak positions. Solid state structural data is presented for M = Ni and Zn, while density functional theory calculated energies, structures and optimized coordinates are provided for the lowest energy cis and trans conformations for L2 as well as [M(L2)2Cl2] with M = Mn, Fe, Co, Ni, Cu, Zn and Cd.

Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

Observed hydrolysis of fluorine substituted bis(ß-diketonato)-dichlorotitanium(IV) complexes.

Novel fluorine substituted mononuclear Ti(ß-diketonato)2Cl2 complexes have been synthesised and shown to be involved in a partial hydrolysis reaction in solution, in which the hydrolyzed dinuclear {Ti(ß-diketonato)2Cl}2(µ-O) is in equilibrium with the monomer. This is in contrast to the solution behaviour of the non CF3-containing Ti(CH3COCHCOCH3)2Cl2, Ti(PhCOCHCOCH3)2Cl2 and Ti(PhCOCHCOPh)2Cl2 complexes, under the same conditions. Variable temperature ((1)H and (19)F) NMR spectra and X-ray structure analyses reveal that the partially hydrolyzed dinuclear complex exists both in solution and in solid state, bridging through a single µ-oxo bridge and having one labile chloro-ligand per titanium center. Inclusion of electron-withdrawing CF3 groups into the already electron-deficient Ti complexes, led to the formation of {Ti(CF3COCHCOCF3)2Cl}2(µ-O) (dinuclear) and [Ti(CF3COCHCOCF3)2(µ-O)]4 (tetranuclear) complexes in CDCl3 containing trace amounts of water. DFT calculated free energies of hydrolysis support the existence of Ti(CH3COCHCOCH3)2Cl2 as a monomer and Ti(CF3COCHCOCF3)2Cl2 as a equilibrium mixture of the monomer and partially hydrolyzed dinuclear {Ti(ß-diketonato)2Cl}2(µ-O) in CDCl3 solution.

Density functional theory calculations of Rh-ß-diketonato complexes.

Density functional theory (DFT) results on the geometry, energies and charges of selected Rh-ß-diketonato reactants, products and transition states are discussed. Various DFT techniques are used to increase our understanding of the orientation of ligands coordinated to Rh, to identify the lowest energy geometry of possible geometrical isomers and to get a molecular orbital understanding of ground and transition states. Trends and relationships obtained between DFT calculated energies and charges, experimentally measured values and electronic parameters describing the electron donating power of groups and ligands, enable the design of ligands and complexes of specific reactivity.

First commissioning results with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS.

Development of a computer assisted gantry system for gaining rapid and accurate calyceal access during percutaneous nephrolithotomy.

PURPOSE: To design a simple, cost-effective system for gaining rapid and accurate calyceal access during percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: The design consists of a low-cost, light-weight, portable mechanical gantry with a needle guiding device. Using C-arm fluoroscopy, two images of the contrast-filled renal collecting system are obtained: at 0-degrees (perpendicular to the kidney) and 20-degrees. These images are relayed to a laptop computer containing the software and graphic user interface for selecting the targeted calyx. The software provides numerical settings for the 3 axes of the gantry, which are used to position the needle guiding device. The needle is advanced through the guide to the depth calculated by the software, thus puncturing the targeted calyx. Testing of the system was performed on 2 target types: 1) radiolucent plastic tubes the approximate size of a renal calyx (5 or 10 mm in diameter, 30 mm in length); and 2) foam-occluded, contrast-filled porcine kidneys. RESULTS: Tests using target type 1 with 10 mm diameter (n=14) and 5 mm diameter (n=7) tubes resulted in a 100% targeting success rate, with a mean procedure duration of 10 minutes. Tests using target type 2 (n=2) were both successful, with accurate puncturing of the selected renal calyx, and a mean procedure duration of 15 minutes. CONCLUSIONS: The mechanical gantry system described in this paper is low-cost, portable, light-weight, and simple to set up and operate. C-arm fluoroscopy is limited to two images, thus reducing radiation exposure significantly. Testing of the system showed an extremely high degree of accuracy in gaining precise access to a targeted renal calyx.

Development of a computer assisted gantry system for gaining rapid and accurate calyceal access during percutaneous nephrolithotomy

PURPOSE: To design a simple, cost-effective system for gaining rapid and accurate calyceal access during percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: The design consists of a low-cost, light-weight, portable mechanical gantry with a needle guiding device. Using C-arm fluoroscopy, two images of the contrast-filled renal collecting system are obtained: at 0-degrees (perpendicular to the kidney) and 20-degrees. These images are relayed to a laptop computer containing the software and graphic user interface for selecting the targeted calyx. The software provides numerical settings for the 3 axes of the gantry, which are used to position the needle guiding device. The needle is advanced through the guide to the depth calculated by the software, thus puncturing the targeted calyx. Testing of the system was performed on 2 target types: 1) radiolucent plastic tubes the approximate size of a renal calyx (5 or 10 mm in diameter, 30 mm in length); and 2) foam-occluded, contrast-filled porcine kidneys. RESULTS: Tests using target type 1 with 10 mm diameter (n = 14) and 5 mm diameter (n = 7) tubes resulted in a 100 percent targeting success rate, with a mean procedure duration of 10 minutes. Tests using target type 2 (n = 2) were both successful, with accurate puncturing of the selected renal calyx, and a mean procedure duration of 15 minutes. CONCLUSIONS: The mechanical gantry system described in this paper is low-cost, portable, light-weight, and simple to set up and operate. C-arm fluoroscopy is limited to two images, thus reducing radiation exposure significantly. Testing of the system showed an extremely high degree of accuracy in gaining precise access to a targeted renal calyx.

GB virus C/hepatitis G virus infection in KwaZulu Natal, South Africa.

Sera from 70 patients on maintenance haemodialysis, 98 patients with chronic liver disease, and 232 volunteer blood donors in the province of KwaZulu Natal, South Africa, were screened for GB virus/hepatitis G virus (GBV-C/HGV) RNA and anti-E2 by reverse transcription-polymerase chain reaction (RT-PCR) and by an enzyme-linked immunosorbent assay (ELISA), respectively. GBV-C/HGV RNA was detected in 17/70 (24.3%) haemodialysis patients, 12/98 (12.2%) patients with chronic liver disease, and 44/232 (18.9%) blood donors (Africans [29/76; 38.2%]; Asians [2/52; 3.8%]; Whites [11/49; 22.4%], and "Coloureds" [persons of mixed origin; 2/55; 3.6%]). Overall (anti-E2 and/or RNA) 43.9% (43/98) of patients with chronic liver disease, 47.1% (33/70) of haemodialysis patients, and 31.9% (74/232) of blood donors (Africans [44/76; 5.9%]; Asians [5/52; 9.6%]; Whites [15/49; 30.6%], and Coloureds [9/54; 16.6%]) were exposed to GBV-C/HGV infection. There was a significant difference in the prevalence of GBV-C/HGV infection (RNA and/or anti-E2) between African blood donors and the other racial groups (P < .001), and between blood donors and haemodialysis patients (P = .02) and patients with chronic liver disease (P = .04). Anti-E2 antibodies and GBV-C/HGV RNA were almost mutually exclusive. GBV-C/HGV-infected haemodialysis patients received more transfusions (P = .03) than noninfected patients. There was no significant difference in liver biochemistry between GBV-C/HGV-infected and noninfected patients and between blood donors in each of the four racial groups. The high prevalence of GBV-C/HGV infection in blood donors and chronic liver disease patients, and the lack of elevated liver enzymes and clinical hepatitis in blood donors and haemodialysis patients, suggest that GBV-C/HGV may not be associated with liver disease.

Comparison of seroprevalences of human herpesvirus-6 and -7 in healthy blood donors from nine countries.

BACKGROUND AND OBJECTIVES: The purpose of the study was to register antibody prevalences of HHV-7 in various locations of the world in comparison to the closely related HHV-6. MATERIALS AND METHODS: Sera of healthy blood donors from nine countries in five continents were titered by indirect immunofluorescent assays using HHV-6 infected HSB2 and HHV-7 infected SupT1 cells. RESULTS: Antibody prevalence for HHV-7 is high (75-98%) in practically all countries except for Northern Japan (44%), with no simple correlation to elevated HHV-6 antibody titers. There were regions of low, intermediate and high mean antibody titers against HHV-7 such as 78.5-91.3 for Belgium, Israel, Japan, USA and Australia, 175.4-182.6 for Mexico and Cologne/Germany, and 389.2 for South Africa for which geographic characteristics may be responsible. CONCLUSION: HHV-7, similar to HHV-6, is a widespread human herpesvirus with elevated antibody titers in the healthy human population essentially everywhere. The data warrant further studies to evaluate its possible pathologic potential, preferentially in persons with defective immune responses.

Detection of Maedi-Visna virus antibodies using a single fusion transmembrane-core p25 recombinant protein ELISA and a modified receiver-operating characteristic analysis to determine cut-off values.

The core p25 and transmembrane (TM) genes of Maedi-Visna virus (MVV) were cloned individually into the pGEX-2T expression vector. Both proteins were expressed as a combined fusion protein in frame with glutathione S-transferase (GST). The purified recombinant antigens (GST-TM and GST-TM-p25) were used to develop a MVV ELISA. A preliminary assessment of the diagnostic potential of the recombinant antigens (GST-TM and GST-TM-p25) was made by testing the antigens against 46 seropositive and 46 seronegative sheep and comparing the results with a commercial p25 ELISA kit. A two-graph receiver operating characteristic (TG-ROC) analysis program was used to interpret the data. The GST-TM-p25 ELISA was more sensitive than the commercial assay which is based on the p25 antigen alone and more specific than the GST-TM ELISA.

Use of NS-4 peptides to identify type-specific antibody to hepatitis C virus genotypes 1, 2, 3, 4, 5 and 6.

The 5' end of the NS-4 protein of different genotypes of hepatitis C virus (HCV) is highly variable in nucleotide and inferred amino acid sequence, with frequent predicted amino acid substitutions between all six of the major HCV genotypes described to date. This region has been shown to be antigenic by epitope mapping, and elicits antibody in HCV-infected individuals with a detectable type-specific component. We have used this sequence data to specify branched peptides for an indirect binding/competition assay to detect type-specific antibody to each major genotype. A total of 183 out of 210 samples (87%) from blood donors and patients with chronic hepatitis C infected with genotypes 1 to 6 showed detectable type-specific antibody to NS-4 peptides that in almost all cases (> 97 %) corresponded to the genotype detected by a PCR typing method. These findings demonstrate the existence of major antigenic differences between genotypes of HCV, and indicate how infection with different variants of HCV may be detected by a serological test.

Two methods for the introduction of amino groups into agarose-based matrices: their use in immunoaffinity chromatography.

In this study two methods of coupling antibody to Sepharose CL2B are described. They involve the introduction of amino groups either via an amino acid such as glycine or through polyethyleneimine. After introduction of amino groups into the matrices, their activation and simultaneous fixing were accomplished by treatment with glutaraldehyde. Monoclonal antibody raised against von Willebrand factor was used as a model ligand to demonstrate the stability and performance of the affinity supports. Both methods examined in this study resulted in good retention of the antibody's binding capabilities and excellent stability of the derivatized matrices. Leaching of the insolubilized protein was considerably less with the polyethyleneimine-glutaraldehyde than with cyanogen bromide.

Natural antibodies to avidin in human serum.

Human serum was found to contain natural antibodies to the egg-white glycoprotein avidin. Of 270 samples tested, all contained antibodies to different extents, mainly of the IgG and IgM classes. Anti-avidin antibodies could be isolated by affinity chromatography.

Use of jacalin as a solid phase in ABO reverse grouping.

A major problem of using red cells as the solid phase in assay systems is the difficulty to bind them strongly to appropriate surfaces. We report here on a number of lectins of different specificities which were examined for their ability to bind red cells to polystyrene 96-well microtitre plates. The use of the Thomsen-Friedenreich antigen-specific lectins, jacalin, mushroom and Maclura pomifera agglutinin proved the most useful for ABO reverse grouping. Jacalin-coated plates were also compared with plates coated with poly-L-lysine and bovine serum albumin/glutaraldehyde for the binding of erythrocyte membranes and were found to be superior. We also describe the colorimetric detection of the solid phase red cell antibody reaction by using an indicator erythrocyte and peroxidase chromogenic substrate.