Manganese (Mn) oxides, which are generally considered biogenic in origin within natural systems, are the only oxidants of Cr(iii) under typical environmental conditions. Yet the influence of Mn biooxide mineral structural evolution on Cr(iii) oxidation under varying geochemical conditions is unknown. In this study we examined the role of light, organic carbon, pH, and the structure of biogenic ...

Manganese is an essential microelement. Manganese deficiency affects reproduction performance and reproductive hormones in layers. However, little is known about its effects and the possible mechanism in regulating reproduction in broiler breeder hens. In the current study, broiler breeder hens at peak production were fed with diets supplemented with 0, 120, or 240 mg of Mn/kg as MnSO4 or Mn pr...

The objective of present study was to assess relationship between biomarkers of Manganese (Mn) and neuropsychological effects. The study was carried out on 27 welders and 31 ferroalloy smelters as Mn-exposed groups and 30 office workers as unexposed controls. Air Mn concentrations were determined according to NIOSH method 7300. The biological samples were prepared using microwave assisted acid ...

The atomic level structure of a series of monodisperse single crystalline nanoparticles with a magnetic core of manganese ferrite was studied using X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) techniques at both the Fe and Mn K-edges, and conventional and high resolution transmission electron microscopy (TEM and HRTEM). In particular, insights on the ...

Evidence has recently been presented that photoinhibition of photosystem II (PSII) is triggered by absorption of light by the oxygen-evolving manganese cluster. To get insight into the effects of light on enzymes containing manganese or other transition metal cofactors, the photosensitivities of Mn catalase, Mn superoxide dismutase, the haem (Fe)-containing bovine liver catalase, and CuZn super...

To investigate the correlations among seminal plasma Magnesium (Mg), Phosphorus (P), Potassium (K), Calcium (Ca), Chromium (Cr), Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Selenium (Se), Molybdenum (Mo) and Iodine (I) concentrations and semen parameters [1– 15]. 500 fertile and 1000 infertile males provided a standardized semen specimen. Total Magnesium (Mg), Phosphorus (P), Potassium (...

We report the first example of a mononuclear nonheme manganese(III)-hydroperoxo complex derived from protonation of an isolated manganese(III)-peroxo complex bearing an N-tetramethylated cyclam (TMC) ligand, [Mn(III)(TMC)(OOH)](2+). The Mn(III)-hydroperoxo intermediate is characterized with various spectroscopic methods as well as with density functional theory (DFT) calculations, showing the b...

Within photosynthetic organisms, the oxygen-evolving complex (OEC) of photosystem II generates dioxygen from water using a catalytic Mn(4)CaO(n) cluster (n varies with the mechanism and nature of the intermediate). We report here the rational synthesis of a [Mn(3)CaO(4)](6+) cubane that structurally models the trimanganese-calcium-cubane subsite of the OEC. Structural and electrochemical compar...

Action of Manganese on Puberty. (May 2007) Bo Yeon Lee, B.S., Chonnam National University Chair of Advisory Committee: Dr. W. Les Dees Manganese (Mn) is considered important for normal growth and reproduction. Because Mn can cross the blood brain barrier and accumulate in the hypothalamus, and because it has been suggested that infants and children are potentially more sensitive to Mn than adul...

The characteristics of manganese and iron binding to human apotransferrin (apo-tf) have been investigated and compared in this study. Both metal ions were taken up by human apo-tf and formed complexes, with the maximum absorbances observed at 410 and 340 nm for manganese-transferrin (Mn-tf) and 465 nm for iron-transferrin (Fe-tf). Addition of manganese (1.5 µg/ml) to the reaction mixture contai...