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Glutamate potentiates lipopolysaccharide–stimulated interleukin-10 release from neonatal rat spinal cord astrocytes
No full textInterleukin-10 (IL-10) has important anti-inflammatory effects and can be protective in inflammatory conditions, such as chronic pain and infection. Exploring factors that modulate IL-10 levels may provide insight into pathomechanisms of inflammatory conditions and may provide a method of neuroprotection during these conditions. Lipopolysaccharide (LPS) stimulation of astrocytes is a source of IL-10; hence, it is of interest to investigate factors that modulate this process. Glutamate is present in increased concentrations in inflammatory conditions, and astrocytes also express glutamate receptors. The present study, therefore, investigated whether glutamate modulates LPS stimulation of IL-10 release from neonatal spinal cord astrocytes. Enzyme-linked immunosorbent assays (ELISAs) were used to quantify IL-10 release from cultured neonatal spinal cord astrocytes, and reverse transcriptase-polymerase chain reaction (RT-PCR) was used to measure IL-10 mRNA expression. Glutamate (1 mM) significantly increased LPS (1 μg/ml)-stimulated IL-10 release from astrocytes by 166% and significantly upregulated IL-10 mRNA levels. Glutamate synergistically signaled through metabotropic glutamate receptor subgroups and the phospholipase C signaling pathway. Spinal cord astrocytes may, therefore, play a larger anti-inflammatory role than first thought in situations where glutamate and a high concentration of Toll-like receptor 4 (TLR4) agonists are present. © 2012 IBRO. Published by Elsevier Ltd
Separation of actinides from spent nuclear fuel: A review.
No full textThis review summarises the methods currently available to extract radioactive actinide elements from solutions of spent nuclear fuel. This separation of actinides reduces the hazards associated with spent nuclear fuel, such as its radiotoxicity, volume and the amount of time required for its’ radioactivity to return to naturally occurring levels. Separation of actinides from environmental water systems is also briefly discussed. The actinide elements typically found in spent nuclear fuel include uranium, plutonium and the minor actinides (americium, neptunium and curium). Separation methods for uranium and plutonium are reasonably well established. On the other hand separation of the minor actinides from lanthanide fission products also present in spent nuclear fuel is an ongoing challenge and an area of active research. Several separation methods for selective removal of these actinides from spent nuclear fuel will be described. These separation methods include solvent extraction, which is the most commonly used method for radiochemical separations, as well as the less developed but promising use of adsorption and ion-exchange materials. This review summarises the methods currently available to extract radioactive actinide elements from solutions of spent nuclear fuel. This separation of actinides reduces the hazards associated with spent nuclear fuel, such as its radiotoxicity, volume and the amount of time required for its’ radioactivity to return to naturally occurring levels. Separation of actinides from environmental water systems is also briefly discussed. The actinide elements typically found in spent nuclear fuel include uranium, plutonium and the minor actinides (americium, neptunium and curium). Separation methods for uranium and plutonium are reasonably well established. On the other hand separation of the minor actinides from lanthanide fission products also present in spent nuclear fuel is an ongoing challenge and an area of active research. Several separation methods for selective removal of these actinides from spent nuclear fuel will be described. These separation methods include solvent extraction, which is the most commonly used method for radiochemical separations, as well as the less developed but promising use of adsorption and ion-exchange materials. © 2016 Elsevier B.V
Investigating the cytotoxicity of platinum(II) complexes incorporating bidentate pyridyl-1,2,3-triazole “click” ligands
No full textSix platinum(II) complexes of the type [Pt(PL)(AL)]2 +, where PL is a bidentate pyridyl-1,2,3-triazole “click” ligand and AL is the R,R or S,S isomer of 1.2-diaminocyclohexane, have been synthesised and characterised by several methods including elemental microanalysis, proton NMR spectroscopy and X-ray crystallography. The in vitro cytotoxicity of each complex was assessed in eleven cell lines, revealing moderate to good activity for complexes incorporating 2-(1-phenyl-1H-1,2,3-triazol-4-yl)pyridine. © 2016 Elsevier B.V
Silver iodide sodalite for 129I immobilisation
No full textSilver iodide sodalite was initially synthesised as a fine-grained major phase in a nominally stoichiometric composition following hot isostatic pressing at 850 °C with 100 MPa and its composition, Ag4Al3Si3O12I, was approximately verified by scanning electron microscopy. An alternative preparative method yielded a more dense and stoichiometric AgI sodalite on sintering and HIPing. As found for AgI, the I is released from AgI sodalite much more readily in reducing water than in ordinary water. Thus in normal PCT-B tests, the I release was <0.3 g/L in water, but it was ∼70 g/L under highly reducing conditions. This is an important point with regard to can material if HIPing is used for consolidation. © 2016 Elsevier B.V
Structural and spectroscopic studies of Ba2Y1−δUO6+x.
No full textA combination of S-XRD and NPD demonstrate the structure of Ba2Y0.879UO6+x to be monoclinic in space group I2/m. That the U is hexavalent is evident from the U L2-edge XANES measurements. This appears to be a rare example of a double perovskite containing vacancies at the octahedral B-sites and interstitial oxygen defects, which combine to stabilise hexavalent U and appears to be a consequence of the preparation of the sample in air. The Y vacancies, coupled with anion disorder, results in a distortion of the BO6 octahedra. © 2016 Elsevier B. V
Hydrothermal synthesis, structures and properties of two uranyl oxide hydroxyl hydrate phases with Co(II) or Ni(II) ions.
No full textTwo new iso-structured uranyl oxide hydroxyl hydrate (UOH) phases with the incorporation of cobalt(II) or nickel(II) ions have been synthesised under hydrothermal conditions and structurally characterised. Both K4Co(OH)3(H2O)9[(UO2)12(O)7(OH)13] (1) and K4Ni(OH)3(H2O)9[(UO2)12(O)7(OH)13] (2) have two-dimensional (2D) polymeric uranyl oxohydroxyl layers with either potassium and hydroxyl cobalt(II) (1) or potassium and hydroxyl nickel(II) (2) ions between layers via uranyl–cation interactions. This work highlights the feasibility of making new UOH phases via a hydrothermal route at relatively higher solution pHs. It also demonstrates that other transition metal ions which are readily available in the environment may also be incorporated into such UOH phases during the natural weathering of uraninite as well as during the storage and disposal of spent nuclear fuels. © 2016 The Royal Society of Chemistr
Crystal structure, thermodynamics, magnetics and disorder properties of Be–Fe–Al intermetallics.
No full textThe elastic and magnetic properties, thermodynamical stability, deviation from stoichiometry and order/disorder transformations of phases that are relevant to Be alloys were investigated using density functional theory simulations coupled with phonon density of states calculations to capture temperature effects. A novel structure and composition were identified for the Be–Fe binary ε phase. In absence of Al, FeBe5 is predicted to form at equilibrium above ∼1100 K, while the ε phase is stable only below ∼1500 K, and FeBe2 is stable at all temperatures below melting. Small additions of Al are found to stabilise FeBe5 over FeBe2 and ε, while at high Al content, AlFeBe4 is predicted to form. Deviations from stoichiometric compositions are also considered and found to be important in the case of FeBe5 and ε. The propensity for disordered vs ordered structures is also important for AlFeBe4 (which exhibits complete Al–Fe disordered at all temperatures) and FeBe5 (which exhibits an order–disorder transition at ∼950 K). © 2015 Elsevier B.V
Production of high specific activity Pt-195m-cisplatinum at South African Nuclear Energy Corporation for phase 0 clinical trials in healthy individual subjects
No full textPlatinum agents continue to be the main chemotherapeutic agents used in the first-line and second-line treatments of cancer patients. It is important to fully understand the biological profile of these compounds in order to optimize the dose given to each patient. In a joint project with the Australian Nuclear Science and Technology Organisation and the Nuclear Medicine Department at Steve Biko Academic Hospital, South African Nuclear Energy Corporation synthesized and supplied (195m) Pt-cisplatinum (commonly referred to as cisplatin) for a clinical pilot study on healthy volunteers. Enriched (194) PtCl2 was prepared by digestion of enriched (194) Pt metal (>95%) followed by thermal decomposition over a 3 h period. The (194) PtCl2 was then placed in a quartz ampoule, was irradiated in SAFARI-1 up to 200 h, then decay cooled for a minimum of 34 h prior to synthesis of final product. (195m) Pt(NH3 )2 I2 , formed with the addition of KI and NH4 OH, was converted to the diaqua species [(195m) Pt(NH3 )2 (H2 O)2 ](2+) by reaction with AgNO3 . The conversion to (195m) Pt-cisplatinum was completed by the addition of concentrated HCl. The final product yield was 51.7% ± 5.2% (n = 5). The chemical and radionuclidic purity in each case was >95%. The use of a high flux reactor position affords a higher specific activity product (15.9 ± 2.5 MBq/mg at end of synthesis) than previously found (5 MBq/mg). Volunteers received between 108 and 126 MBq of radioactivity, which is equivalent to 6.8-10.0 mg of carrier cisplatinum. Such high specific activities afforded a significant reduction (~50%) in the chemical dose of a carrier cisplatinum, which represents less than 10% of a typical chemotherapeutic dose given to patients. A good manufacturing practice GMP compliant product was produced and was administered to 10 healthy volunteers as part of an ethically approved Phase 0 clinical trial. The majority of the injected activity 27.5% ± 5.8% was excreted in the urine within 5 h post injection (p.i.). Only 8.5% ± 3.1% of cisplatinum remained in blood pools at 5 h, which gradually cleared over the 6-day monitoring period p.i. At the end of the study (6 days p.i.), a total of 37.4% ± 5.3% of the product had cleared from the blood into urine, and approximately 63% remained in the body. The significantly lower concentration of carrier cisplatinum used for imaging resulted in a well-tolerated product. © 2013 John Wiley & Sons, Ltd
Scanning force microscopy of 129Iodine surface impact structures in muscovite, zircon and apatite as proxies for damage of simulated fission fragments in solids
No full textUsing artificially created swift, heavy ions of 129I with a typical fission-fragment mass and specific energies which are common during the spontaneous fission of 238U, the response in minerals commonly used in geochronological dating such as muscovite, zircon and apatite, has been evaluated by the means of Atomic Force Microscopy (AFM). The surface impact structures form hillocks with greater diameters but smaller heights for low-energetic ions and smaller diameters but greater heights for high-energetic ions. The observed hillock widths range from 22 ± 2 nm for low-energetic ions to 17 ± 1 nm for the highest energy in mica. Furthermore, the dimensions formed in apatite for low and high-energy ions range from 53 ± 2 nm to 27 ± 2 nm and from 64 ± 3 nm to 28 ± 1 nm in zircon. With increasing 129I particle energy hillock heights increase, but diameters decrease regardless of mineral orientation. The crystallographic orientation of apatite and zircon also seems to have no effect on hillock dimensions, which are identical for perpendicular and parallel to the c-axis oriented mineral grains. The results support the “Compound Spike” track formation model of Chadderton (2003), which combines the Coulomb ion explosion model with a thermal spike model. © 2013 Elsevier Ltd
Dinuclear complexes of europium(III) and gadolinium(III) ions with a julolidine–quinoline-based tridentate ligand
No full textThe reaction of europium(III) or gadolinium(III) acetates with a Schiff base ligand {HL (C22H21N3O) = ((E)-9-((quinolin-8-ylimino)methyl)-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-8-ol)} in methanol affords two dinuclear complexes which have been characterized by powder X-ray diffraction, Raman spectroscopy, scanning electron microscope–electron dispersive spectroscopy, absorption and emission spectroscopies as well as single-crystal X-ray diffraction. [Eu2L2(CH3COO)4(CH3OH)2] (1) and [Gd2L2(CH3COO)4(CH3OH)2] (2) are iso-structures, each consisting of two M : L : CH3COO : CH3OH (1 : 1 : 1 : 1) units bridged by two acetate anions with the metal center in a distorted capped square antiprismatic coordination geometry. Their vibration modes, electronic structures, and photoluminescent properties are reported. © 2016 Taylor & Francis Grou