Studies of biodegradability of certain oils in forest soil as determined by the respirometric BOD OxiTop method

The suitability of the respirometric BOD OxiTop method for biodegradation studies of different oils in soil was assessed. Different forestry chain oils and wood-preservative oils were used as model substances. Experiments were carried out on different types of Finnish forest soils. The results of these experiments are in good agreement with our earlier results of oil-biodegradation experiments in water. The BOD OxiTop method proved to be a highly suitable analysis method for biodegradation studies of oils in soil.     

Specificity of 15N NMR chemical shifts to the nature of substituents and tautomerism in substituted pyridine N-oxides

¹H, ¹³C, and ¹⁵N NMR chemical shifts have been measured for 2-aminopyridine N-oxide (1), its eleven derivatives (2–10, 13, 14), and 3-Cl and 3-Br substituted 4-nitropyridine N-oxides (11, 12). δ(¹⁵N) of pyridine ring nitrogen in 2-acetylaminopyridine N-oxides are 5.9–11.5 ppm deshielded from those in 2-aminopyridine N-oxides. When amino and acetylamino substituents are in 4-position, δ(¹⁵N) of ring nitrogen is 21.3 ppm deshielded in the acetylated derivative. The strong resonance interaction between 2-amino and 5-nitro groups reflects in the decrease of amino nitrogen shielding about 5.3–17.9 ppm. Also, ¹H and ¹³C NMR spectral data are in agreement with ¹⁵N NMR results reflected as deshielded amino protons and carbons C-2 and C-5. The pyridine nitrogen chemical shift in all amino- and acetylamino derivatives vary between ?101.2 and ?126.7 ppm, which has been connected with the tautomeric balance in our earlier studies.     

Photochemical Characterization of Up-Converting Inorganic Lanthanide Phosphors as Potential Labels

We have characterized commercially available up-converting inorganic lanthanide phosphors for their rare earth composition and photoluminescence properties under infrared laser diode excitation. These up-converting phosphors, in contrast to proprietary materials reported earlier, are readily available to be utilized as particulate reporters in various ligand binding assays after grinding to submicron particle size. The laser power density required at 980 nm to generate anti-Stokes photoluminescence from these particulate reporters is significantly lower than required for two-photon excitation. The narrow photoluminescence emission bands at 520–550 nm and at 650–670 nm are at shorter wavelengths and thus totally discriminated from autofluorescence and scattered excitation light even without temporal resolution. Transparent solution of colloidal bead-milled up-converting phosphor nanoparticles provides intense green emission visible to the human eye under illumination by an infrared laser pointer. In this article, we show that the unique photoluminescence properties of the up-converting phosphors and the inexpensive measurement configuration, which is adequate for their sensitive detection, render the up-conversion an attractive alternative to the ultraviolet-excited time-resolved fluorescence of down-converting lanthanide compounds widely employed in biomedical research and diagnostics.     

Eine Charakterisierung der fast schwach modularen Verbände

Ohne ZusammenfassungAlexander von Humboldt-Stipendiat am Mathematischen Institut der Universität Bonn.