Uranium and plutonium containing particles in a sea sediment sample from Thule, Greenland

Particles composed of radioactive materials and probably originating from US nuclear weapons were identified in sea sediment samples collected from Thule, Greenland, in 1997. The weapons were destroyed close to the Thule Air Base in 1968 in an aeroplane crash, which dispersed radioactive materials in the environment. The presence of particulate radioactive materials in the sediment samples was revealed by combining gamma-spectrometry and autoradiography. Isolation and separation of a radioactive particle from a bulk sample were performed using autoradiography, phosphor plate imaging and scanning electron microscopy. Using X-ray microanalysis as well as alpha and beta activity analysis, U and weapons-grade Pu were detected in the granular, brittle particle.     

Rapid analysis of peptide toxins in cyanobacteria

A quick and easy-to-perform method for routine analysis of cyanobacterial (blue-green algal) peptide toxins is proposed. The toxins are analysed by means of high-performance liquid chromatography using a recently developed internal surface reversed-phase column. The sample clean-up work is minimized and the total analysis time is thus shortened considerably compared to previously described methods.     

A comment on classical rainbow angles for atom-atom scattering

The dependence of the rainbow angle on the depth of the potential well, the equilibrium distance, andthe force constant of the potential are discussed for several potential functions.     

Solvent delivery in the new application areas of high-performance liquid chromatography

Summary The development of new column packings for biological macromolecules, as well as the techniques for handling micropacked columns, sets new demands on solvent delivery systems for HPLC. The main implications of these developments with respect to pump design are discussed and the evaluation of a solvent delivery system (pump and gradient programmer) optimized for these purposes is presented.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Determination of dγ/dT for water by means of a differential technique

The temperature derivative of the surface tension of water has been measured by means of the Wilhelmy method using an electrobalance and a differential technique. No anomalies were observed; −dγ/dT was found to be a slowly increasing linear function of T within the temperature range 5–40°C.     

Enzymes involved in cellulose and lignin degradation

A detailed presentation was given of the discovered and studied enzymes involved in degradation of cellulose and lignin by the white-rot fungus,Sporotrichum pulverulentum (Phanerochaete chrysosporium). The fungus utilizes, for the degradation of cellulose: (a) Five different endo-1,4-Β-glucanases (b) One exo-1,4-Β-glucanase (acting synergistically with the endoglucanases) (c) Two 1,4-Β-glucosidases The regulation, induction, and catabolite repression of the endoglucanases have been studied in depth and the results of these studies were also presented. In addition to the hydrolytic enzymes,S. pulverulentum also produces the oxidative enzyme cellobiose oxidase that is of importance for cellulose degradation. Another unconventional enzyme is cellobiose: quinone oxidoreductase, which is of importance for both cellulose and lignin degradation. It reduces quinones from the lignin under oxidation of cellobiose from the cellulose. It has recently been discovered thatS. pulverulentum produces two acidic proteases of importance for cellulose degradation since they enhance the endoglucanase activity, particularly in young cultures of the fungus grown on cellulose. The enzymes involved in lignin degradation are not known nearly as well as these involved in cellulose degradation. However, extracellular phenol oxidases, laccase, and peroxidase have been shown to be involved in and necessary for lignin degradation to take place. A phenol oxidase-less mutant ofS. pulverulentum cannot degrade lignin unless a phenol oxidase is added to the medium. Recently, an enzyme splitting the α—Β bond in the propane side chain has been discovered by Kirk and coworkers. Several enzymes involved in the metabolism of vanillic acid, always a metabolite in lignin degradation, have been discovered and studied in our laboratory. Presentations of the enzymes for decarboxylation, demethoxylation, methanol oxidation, ring cleavage, and intracellular quinone reduction by NAD(P)H: quinone oxidoreductase were given. A discussion of possibilities for a specific enzymic primary attack on the native lignin, as well as of the likeliness for an unspecific radical nature of this attack, was also given.     

Specific features of the structure and electrical conductivity of the magnetically ordered oxide (La0.9Sr0.1)(Fe0.8Mg0.2)O3?y

The structure of the (La_0.9Sr_0.1)(Fe_0.8Mg_0.2)O_{3− y} oxide is investigated using neutron diffraction at temperatures of 10, 295, 500, 700, and 1000 K. The results of the structure refinement are in good agreement with the experimental data on the electrical conductivity and confirm the inference that the oxidation state of iron cations is higher than 3+ and that the structure of the compound is antiferromagnetically ordered at temperatures below 500 K. Original Russian Text ? S.A. Ivanov, G.M. Kaleva, A.V. Mosunov, E.D. Politova, S.-G. Eriksson, 2008, published in Kristallografiya, 2008, Vol. 53, No. 1, pp. 69–75.