Iron supply is thought to regulate primary production in high nitrate, low chlorophyll (HNLC) regions of the sea in both the past and the present. A critical aspect of this relationship is acquisition of iron (Fe) by phytoplankton, which occurs through a complex series of extracellular reactions that are influenced by Fe chemistry and speciation. During the first in situ mesoscale Fe-enrichment...

Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation anal...

A major goal of island biogeography is to understand how island communities are assembled over time. However, we know little about the influence of variable area and ecological opportunity on island biotas over geological timescales. Islands have limited life spans, and it has been posited that insular diversity patterns should rise and fall with an island's ontogeny. The potential of phylogeni...

Iron speciation in rodent diet and rat gastrointestinal tract lumen during dietary digestion and absorption was investigated with a novel selective extraction technique. Five Fe fractions were identified, namely exchangeable (soluble in 1 M-magnesium chloride), carbonate-bound (soluble in mild acid), oxide-bound (soluble in hydroxylamine-acetic acid), organic-bound (soluble after treatment with...

In living systems iron appears predominantly associated with proteins, but can also be detected in forms referred as labile iron, which denotes the combined redox properties of iron and its amenability to exchange between ligands, including chelators. The labile cell iron (LCI) composition varies with metal concentration and substances with chelating groups but also with pH and the medium redox...

Worldwide contamination of waters by metals, metalloids, and organometallic pollutants is a major health issue. In particular, the occurrence selenium metalloid at rather high concentrations in environment, especially water compartment, increasing concern, notably developing countries. Selenium difficult to remove from groundwater industrial effluents because often present complex polycontamina...

Cardiosiderosis is a leading cause of mortality in transfusion-dependent thalassemias. Plasma non-transferrin-bound iron and its redox-active component, labile plasma iron, are key sources of iron loading in cardiosiderosis. Risk factors were identified in 73 patients with or without cardiosiderosis. Soluble transferrin receptor-1 levels were significantly lower in patients with cardiosiderosis...

The possibility of application of 4-nitrocatechol (4-NC) - tetrazolium salt - organic solventsystems for liquid-liquid extraction-spectrophotometric vanadium (IV and V) speciation wasstudied. Six commercially available tetrazolium salts (2,3,5-triphenyltetrazolium chloride (TTC),3-(2-naphtyl)-2,5-diphenyltetrazolium chloride (Tetrazolium Violet, TV); 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyltetra...

The iron-oxygen system is the most important reference of rocks' redox state. Even as minor components, iron oxides can play a critical role in redox equilibria, which affect the speciation of the fluid phases chemical differentiation, melting, and physical properties. Until our recent finding of Fe4O5, iron oxides were assumed to comprise only the polymorphs of FeO, Fe3O4, and Fe2O3. Combining...