Mössbauer investigation on the crystal field splitting of Fe ion in zinc fluosilicate

The Mössbauer quadrupole interaction ΔE_Q of the Fe²⁺ ion has been measured with 2% at. ⁵⁷Fe in ZnSiF₆·6H₂O, between 1.3 and 20°K. The sign of ΔE_Q (< 0) has been determined by using a single crystal absorber. These results are interpreted in terms of a trigonal crystal field potential that splits the Fe²⁺ orbitals into a ground state singlet and a first excited doublet whose distance is much smaller than that reported for FeSiF₆·6H₂O, in reasonable agreement with previous EPR measurements.     

Heterocyclic N-glycosyl derivatives—XIII: Reaction of 6-chloropurine and benzotriazoles with acetylated glycals

Acid-catalysed reactions of tri-O-acetyl-D-glucal with benzotriazole, 5,6-dimethylbenzotriazole, 5,6-dichlorobenzotriazole and 6-chloropurine have been found to give anomeric mixtures of the corresponding 2′,3′-unsaturated N-glycosyl derivatives with the α-anomers preponderating. When tri-O-acetyl-D-galactal was used the 3′,4′,6′-tri-O-acetyl-α- and β-D-lyxo-hexopyranosyl nucleoside analogs were obtained. The conformation and anomeric configuration of all the N-glycosyl compounds obtained were assigned by NMR studies.     

Determination of227Ac in geological materials through neutron activation and alpha-spectrometric assay of induced228Th

A new route has been developed for the micro-determination of²²⁷Ac in geological materials by neutron activation. The method is based on intense neutron irradiation of the analysed samples followed by separation and α-spectrometric determination of²²⁸Th, the β-decay product of the 6.1 hrs²²⁸Ac isotope formed. Two alternatives are considered for analysis related to the origin of the analysed matrix. The high sensitivity of the method is documented by the determination of 10^?17 g²²⁷Ac/g sample. The method is successfully applied for age determination of five uranium containing materials and old uranium glass from Bohemia, CSSR.     

Trennung von V,Cr und Mn aus Stahl und Aktivierungsanalyse der Legierungselemente mit 14 MeV-Neutronen

The elements are separated from iron by solvent-extraction. Cr, V and Mn are separated by ion-exchange chromatography with a strong acidic cation-exchanger. The elements are determined by 14 MeV-neutron activation analysis using γ-spectroscopy. The method is suitable for a concentration range of 0.05 to 5%.     

Study of occupational health impact of atmospheric pollution on exposed workers at an iron and steel complex by using neutron activation analysis of scalp hair

The occupational health impact of atmospheric pollution on exposed workers at one iron and steel complex was studied by instrumental neutron activation analysis of workers' hair samples and medical examination. The experimental results indicate that there is a positive correlation between the high inhalation amounts of iron and other trace elements by the exposed workers and the symptom of their high blood pressure and hypoglycemia, which implies that the atmospheric environment polluted by iron and steel industry has an adverse health impact on the exposed workers. The measures to relieve and abate the occupational diseases caused by air-borne particulate matter should be taken     

Evaluation of some essential and trace elements in diets from 3 nurseries from Juiz de Fora, M.G., Brazil, by neutron activation analysis

A study was made in diets offered to a group of pre-school children,whose mean age was 67 months and remained the whole day in three day carecenters from Juiz de Fora, M.G., Brazil. For sampling, the duplicate portiontechnique was used, and the diets were collected and analyzed separately eachday in the 3 nurseries. Instrumental neutron activation analysis was appliedto the determination of 16 elements. The daily dietary intake values werecompared to the RDA (children 4–6 years old). Based on this reference,Ca, Fe, Se and Zn were found to be deficient, Mg and Mn were comparable tothe RDA and the Cl and Na concentrations were higher compared to their RDA.For the other elements measured, there are no RDA's for children.     

Tetrathiafulvalene-acetylene scaffolding: new pi-electron systems for advanced materials

Novel extended tetrathiafulvalenes (TTFs) with hexa-2,4-diyne-1,6-diylidene spacers between the two 1,3-dithiole rings and laterally appended alkynyl moieties for one- and two-dimensional scaffolding were synthesised and investigated for their electronic properties.     

Anodic synthesis and molecular structure of dodecaethylhexaamidobisphosphonium diperchlorate

The electrochemical oxidation of hexaethyl triamidophosphite in the absence of nucleophiles specially introduced into the electrolyte was studied by anodic voltamperometry and preparative electrolysis. The reversible one-electron oxidation of the triamidophosphite molecule gives an unstable radical-cation, which reacts with a molecule of the starting compound to give a dimeric radical-cation, whose subsequent oxidation leads to dodecaethylhexaamidobisphosphonium diperchlorate. This product is the first example of an acyclic, doubly charged bisphosphonium cation with a . The crystal structure of this compound was obtained by x-ray diffraction structure analysis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 664–669, March, 1990.     

Applicability of dynamic change of pH in the capillary zone electrophoresis of proteins

A method to extend the separation power of CZE is described. The method is based on the separation of sample components at two different pH values during one separation run, and involves dynamic buffering of the pH inside a separation capillary by controlling the flow of H+ ions from the anodic electrode chamber. By changing the anolyte in the chamber, a dynamic pH step is generated, which proceeds rapidly along the capillary and establishes the required new pH value. The use of the method has been demonstrated by the cationic separation of a model mixture of proteins.     

Determination of Mg,Al, P,Cu and Mn in biological fluids by neutron activation analysis

Thermal and epithermal neutron activation analysis has been applied to determine the concentrations of magnesium, aluminium, phosphorus, copper and manganese in two biological fluids: blood serum and market milk. Both epithermal neutron irradiation and radiochemical separation (a chromatographic column of HAP) were used to get rid of the interferences from 24-Na. Strongly acidic solutions of the irradiated samples were passed through the columns of HAP, where sodium was completely adsorbed while, Al, Cu, Mg and Mn were eluted with an efficiency of 99±1%. Since both Al and P were determined through the formation of²⁸Al (2.24 min) thermal and epithermal neutron activation have been applied in order to determine the contribution of each radionuclide to²⁸Al activity. The determination of Mg, Al and P in milk samples was done instrumentally, whereas in the case of blood serum with higher concentration of Na, a radiochemical separation is essential in both cases. The concentrations of Al, Cu, Mg, Mn and P in blood serum and market milk were found to be 0.24±0.02 and 1.85±0.09 g Al/ml, 1.35±0.04 and 0.068±0.005 g Cu/ml, 22.9±1 and 98.9±8.6 g Mg/ml, 22±3 and 16±2 ng Mn/ml and 167±13 and 865±32 g P/ml, respectively.