A microanalytical study of Pb and Cu uptake coupled to siderite dissolution

Heavy metal contamination of aqueous environments is a worldwide problem and remediation is particularly challenged by natural redox fluctuations, causing acidity and increased metal solubility. Siderite (FeCO₃) is a promising candidate material for heavy metal sequestration, as its carbonate component may regulate acidity, while the redox active Fe(II) component may act as reductant or as sorbent upon oxidative precipitation as Fe(III) (oxyhydr)oxides. To tap the full potential of siderite and its auspicious properties, this thesis investigates the efficacy of metal uptake coupled to siderite dissolution from oxic and anoxic acidic aqueous solutions. Lead (Pb) and copper (Cu) are chosen as case studies for weakly (Pb) and strongly (Cu) redox active metals. In laboratory experiments, metal uptake and pH development are monitored during siderite dissolution in Pb- and Cu-bearing oxic and anoxic acidic waters. Special focus is laid on characterising the solid reaction products using high-resolution analyses to determine the metal speciation and type of bonding decisive for metal retention. Siderite surface-controlled adsorption and dissolution–precipitation reactions buffer the reactive solution pH, while the properties of the dissolved metals determine the reaction pathways. Under oxic conditions, metals predominantly adsorb onto secondary Fe(III) (oxyhydr)oxide precipitates, while under anoxic conditions, metals are captured by sparingly soluble cerussite (PbCO3) and native copper precipitation. Key to these processes is the continuous dissolution of siderite, which is promoted by non-epitaxial growth and phase transformations of the precipitates on the reacting siderite surface. This study corroborates the great potential of siderite dissolution to remediate metal polluted water-saturated dynamic redox environments by counteracting acidity and capturing metals in secondary minerals. The thorough documentation of the reaction products and mechanisms advances our understanding of siderite–metal (redox) interactions to predict sustainable metal contaminant immobilisation and metal cycling in other modern and ancient Fe(II) and carbonate-rich natural aqueous environments

Prediction of phonological and gender information: an event-related potential study in Italian

Do people predict different aspects of a predictable word to the same extent? We tested prediction of phonological and gender information by creating phonological and gender mismatches between an article and a predictable noun in Italian. Native Italian speakers read predictive sentence contexts followed by the expected noun (e.g., un incidente: ‘accident’) or another plausible, but unexpected noun, either beginning with a different phonological class (consonant vs. vowel, e.g., uno scontro: ‘collision’; phonological mismatch) or belonging to a different gender class (e.g., un'inondazione: ‘flooding’; gender mismatch). Phonological mismatch articles elicited greater negativity than expected articles at posterior channels around 450–800 ms post-stimulus. In contrast, gender mismatch articles elicited greater negativity than expected articles at left posterior channels around 250–800 ms. Unexpected nouns showed an N400 effect followed by frontal positivity relative to expected nouns. The earlier effect for the gender mismatch articles suggests that people are quicker or more likely to pre-activate gender information vs. phonological information of a predictable word. We interpret the results with respect to production-based prediction accounts

Verschiedene Szenarien zu Abrechnung und Kostenerstattung eines präoperativen Managements der Eisenmangelanämie im deutschen Gesundheitssystem

More than 30% of all patients undergoing surgery suffer from preoperative anemia. Iron deficiency anemia is the most common type of anemia. The diagnostics and treatment of iron deficiency anemia can be carried out before patients undergo surgery as an alternative to blood transfusion and is an interdisciplinary task. This article gives an overview of various billing modalities and payment arrangements for management of preoperative anemia in the German healthcare system