Recent radiochemical studies of the fission process

This article summarizes the recent radiochemical investigations on mass, charge kinetic energy and fragment angular distributions in low energy fission of actinides.     

Rhenium‐Dicarbonyl‐Nitrosyl‐Komplexe mit Imidazol

Rhenium Dicarbonyl‐Nitrosyl Complexes with Imidazole Different rhenium‐dicarbonyl‐nitrosyl complexes with imidazole (Im) as monodentate ligand have been synthesized and characterized, starting from [NEt₄][ReCl₃(CO)₂(NO)] and [ReCl(μ?Cl)(CO)₂(NO)]₂. Whereas the complexes [ReCl₂(Im)(CO)₂(NO)] and [ReCl(Im)₂(CO)₂(NO)]⁺ were achieved in high yields, the complex [Re(Im)₃(CO)₂(NO)]²⁺ with three imidazole ligands could only be isolated after complete removal of all halide ions (with AgBF₄) in low yield. The synthesis of a corresponding ^99mTc‐dicarbonyl‐nitrosyl complex with imidazole opens a new perspective for such compounds as potential radiopharmaceuticals and alternatives to the already established ^99mTc‐tricarbonyl complexes.     

核化学与放射化学的研究进展

在我国核能快速发展的新形势下,新型核能资源的开发、乏燃料后处理、放射性废物处理与处置等核燃料循环化学研究日益活跃。随着科学技术的不断发展,离子加速器、反应堆、各种类型的探测器和分析设备、以及计算机技术等的发展,核化学与放射化学研究的范围和成果在不断扩展和增加,如核安全、环境放射化学、放射分析化学、放射性药物与标记化合物等,研究成果对于国防建设、核能发展、核技术应用等方面具有重要支撑作用。本文综述了近年来国内在上述领域所取得的研究进展。共引用参考文献161篇。     

Photochemical Conjugation and One‐Pot Radiolabelling of Antibodies for Immuno‐PET

Monoclonal antibodies (mAbs), immunoglobulin fragments, and other proteins are important scaffolds in the development of radiopharmaceuticals for diagnostic immuno‐positron emission tomography (immuno‐PET) and targeted radioimmunotherapy (RIT). Conventional methods for radiolabelling proteins with metal ions such as ⁶⁸Ga, ⁶⁴Cu, ⁸⁹Zr, and ⁹⁰Y require multi‐step procedures involving pre‐purification, functionalisation with a chelate, and subsequent radiolabelling. Standard coupling chemistries are time‐consuming, difficult to automate, and involve synthesis, isolation, and storage of an intermediate, new molecular entity (the conjugated mAb) whose biochemical properties can differ from those of the parent protein. To circumvent these issues, we developed a photoradiochemical approach that uses fast, chemoselective, light‐induced protein modification under mild conditions with novel metal‐ion‐binding chelates derivatised with aryl azide (ArN₃) groups. Experiments show that one‐pot photochemical conjugation and radiolabelling of formulated mAbs can be achieved in <20 min.     

Determination of90Sr and 137Cs concentrations in the IAEA reference material Soil-6

Vezetéknév This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of plasticizer and surface topography on the cleanability of plasticized PVC materials

A quantitative radiochemical measuring procedure was used to investigate soil adhesion on laboratory-made polyvinyl chloride (PVC) surfaces. The materials contained different plasticizers and microstructures. Both the quality and amount of plasticizers and the microstructure affected the cleanability of the PVC samples. The surface topography and structures were examined with a contact angle meter, atomic force microscopy (AFM) and a contact profilometer.     

Challenges and successes in the use of neutron activation analysis procedures for value assignment of animal serum and bovine liver Standard Reference Materials

Analyses for value assignment in the renewal Standard Reference Materials^® SRM 1598a Animal Serum and SRM 1577c Bovine Liver included extensive characterization by neutron activation analysis (NAA). Conventional instrumental NAA procedures were complemented by pre-irradiation chemical separations for the determination of Al, V, Mn, and Cu, radiochemical separations for the determination of Ag, As, Cd, Cr, Cu, Mo, Sb, and Se, and the use of (anti-) coincidence gamma-ray spectrometry systems for the instrumental determination of Ag, Cr, and Hg. The previous materials, SRMs 1598, 1577, and 1577b, were analyzed together with the new materials for quality control.     

Radwaste Immobilization by Structural Modification—the Crystallochemical Properties of SYNROC,a Titanate Ceramic

New studies utilizing electron microscopic techniques have revealed the immobilization of radionuclides in crystalline ceramic waste forms to be not merely a question of substituting waste elements into the appropriate crystallographic sites of a host matrix. Rather than entering the ceramic as a “continuous” solid solution it has been found that the incorporation of highly radioactive waste elements is commonly accompanied by structural modification. This may take the form of cation ordering, crystallographic shear, or twinning on a unit cell scale. Such mechanisms considerably enhance the capacity of a ceramic to immobilize (simulated) radwaste and impart to it the flexibility to respond to inevitable variations in wastestream composition.     

Chemical Effects of Nuclear Transformations in Solids

Nuclear reactions and radioactive transformations offer the possibility of investigating the chemical reactions of “bare” nuclei. The interest in such chemical processes following nuclear transformations has already led to two international symposia^[1,2]. In solids, the chemical reactions of recoil nuclei having energies lower than 1 keV proceed not via molten states, but via regions of little disorder.