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Monitoring of bacterial biodiversity in anaerobic membrane bioreactors (AnMBRs) dealing with wastewater containing X-ray contrast media compounds

Węgrzyn A., Żabczyński S.

Environment Protection Engineering

2014

Vol. 40, nr 1

151--164

Iodinated contrast media compounds (ICM) have been identified in wastewater within the last 20 years. In this study, the biodiversity of activated sludge in anaerobic membrane bioreactors dealing with synthetic hospital wastewater with addition of ICM was investigated, using fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE). During the adaptation of microorganisms to anaerobic growth conditions and to ICM presence, differences in the content of Alpha- and Betaproteobacteria were noted and bioreactors showed higher biological diversity (H = 2.9), suggesting that ICM were not toxic to the bacteria. The long sludge age had the strongest influence on the composition of activated sludge biocenosis.

Środki kontrastowe do obrazowania magnetyczno-rezonansowego na przykładzie związków kompleksowych żelaza

Kuźnik N., Wyskocka M.

Wiadomości Chemiczne

2013

[Z] 67, 7-8

665--694

Nuclear magnetic resonance is already a broadly exploited phenomenon both in chemistry and medicine. Magnetic resonance imaging is a routine technique in medical diagnosis readily applied for soft tissues like brain, cardiovascular system or gastrointestinal tract. Contrast agents stepped into the field and enabled better recognition of a lesion in the early stage of a disease. The authors present an introductory description of a fascinating history, classification of contrast agents followed by the mechanisms of their action. Classes of positive and negative contrast agents are described. Further discussion is focused on the T1 (positive) molecular species. The mechanism was divided into (1) inner sphere, where both direct coordination of water molecule and its presence in second sphere is considered (Fig. 1) [1] and (2) an outer sphere mechanism which is assumed for the water molecules diffusing into the surrounding of the paramagnet [21, 28]. Further, the most important requirements for medical applications are given. Those are: high relaxivity, charge-osmolality, stability, toxicity via potential transmetallation of redox activity [42]. Molecular examples are quoted based on previously investigated iron complexes. Majority of them are iron(III) species [68], however, some iron(II) compounds like activable, self-immolative or ParaCEST systems have recently appeared [86, 89]. Iron compounds as positive contrast agents may soon accompany classic gadolinium complexes.