Papierchromatographische Untersuchung von Thyroxin und anderen Jodthyroninen

The Science of Nature -     

Effect of Cross-Linking Waste Protein with Dialdehydes on Its Biodegradation Under Anaerobic Conditions

Most native polymers used in processing and application technologies are admittedly disposable from the environment in a biologic manner, but products possess low mechanical strength. One of the paths to increasing this attribute (if feasible) is their cross-linking, which may, however, affect their readiness to biodegradation. In the presented work this condition was observed on the example of waste protein (Hykol B) cross-linking by means of glutardialdehyde and glyoxal. Degree and course of cross-linking were determined through impedance spectroscopy. The objective of this work also was to obtain data for constructing a sensor capable of following the cross-linking course in real time, for potential industrial application of Hykol in continuous production. Impedance spectroscopy proved to be applicable even to this kind of material marked by considerable water content and exhibiting relatively high electric conductivity; so far it had been used only for materials of low conductivity. An aqueous environment inoculated with digested anaerobic sludge from a municipal wastewater treatment plant was selected for modeling anaerobic conditions. The relation was studied between cross-linking degree given by content of cross-linking agent (determined by impedance spectroscopy) and biodegradation degree under anaerobic conditions. It was confirmed that network density as given by quantity of added agent not only reduced breakdown degree but also slowed the course of the process. This fact is particularly obvious with cross-linking by means of glyoxal; network density is thus dependent on type of employed substance, which affect type and structure of created network. That not merely forms an obstacle during polymer swelling and dissolution but also prevents access of bacteria to source of metabolized organic carbon.     

Physiological responses to atmospheric fluorine pollution in transplants of Pseudoscleropodium purum

Transplants of the moss Pseudoscleropodium purum were placed under shade, and with an auto irrigation system, at five sites in the surroundings of an aluminium smelter to enable study of the possible effects of F on different physiological parameters after exposure periods of 28 and 56 days. Reference thresholds for the content of Chl a+b and for the pigment indexes of Chl a/b and D665/D665a were established with the data corresponding to 22 transplants of each duration of exposure, at seven sites where there was little or no contamination by F. The highest determination coefficients for the levels of F in moss were those obtained for chlorophyll content (Chl a+b) and the D665/D665a pigment index, with the effects being most evident in the transplants exposed to the contamination for 56 days.