In this Letter, we experimentally show that the room temperature ferromagnetism in the Mn-Zn-O system recently observed is associated with the coexistence of Mn(3+) and Mn(4+) via a double-exchange mechanism. The presence of the ZnO around MnO(2) modifies the kinetics of MnO(2)-->Mn(2)O(3) reduction and favors the coexistence of both Mn oxidation states. The ferromagnetic phase is associated wi...

Manganese-oxidizing bacteria in the aquatic environment have been comprehensively investigated. However, little information is available about the distribution and biogeochemical significance of these bacteria in terrestrial soil environments. In this study, stratified soils were initially examined to investigate the community structure and diversity of manganese-oxidizing bacteria. Total 344 c...

The potential for Mn oxides to modify the biogeochemical behavior of U during reduction by the subsurface bacterium Shewanella putrefaciens strain CN32 was investigated using synthetic Mn(III/IV) oxides (pyrolusite [ -MnO2], bixbyite [Mn2O3] and K -birnessite [K4Mn14O27 8H2O]). In the absence of bacteria, pyrolusite and bixbyite oxidized biogenic uraninite (UO2[s]) to soluble U(VI) species, wit...

The oxygen-evolving complex (OEC) of photosystem II contains a Mn(4)CaO(n) catalytic site, in which reactivity of bridging oxidos is fundamental to OEC function. We synthesized structurally relevant cuboidal Mn(3)MO(n) complexes (M = Mn, Ca, Sc; n = 3,4) to enable mechanistic studies of reactivity and incorporation of μ(3)-oxido moieties. We found that Mn(IV)(3)CaO(4) and Mn(IV)(3)ScO(4) were u...

We report an in situ soft chemical synthesis of a novel hybrid material, cellulose-nanoscale-manganese oxide composite (C-NMOC), and its application for Pb(II) removal from aqueous solutions. For comparison, detailed Pb(II) adsorption studies were also performed with nanoscale-manganese oxide powder (NMO), prepared through a similar route. Various spectroscopic and microscopic techniques were u...

Manganese oxides are often highly reactive and easily reduced, both abiotically, by a variety of inorganic chemical species, and biologically during anaerobic respiration by microbes. To evaluate the reaction mechanisms of these different reduction routes and their potential lasting products, we measured the sequence progression of microbial manganese(IV) oxide reduction mediated by chemical sp...

Herein, we report the luminomagnetic bifunctional properties of two-dimensional (2D) Mn(2+) bonded graphene oxide (GO)/reduced graphene oxide (RGO) nanosheets synthesized using a facile route of oxidation followed by a solvothermal reduction method. Photoluminescence (PL) studies (excited by different wavelengths) revealed that the resonant energy transfer between Mn(2+) and sp(3)/sp(2) cluster...

BACKGROUND Studies in monkeys with intranasally instilled gold ultrafine particles (UFPs; <100 nm) and in rats with inhaled carbon UFPs suggested that solid UFPs deposited in the nose travel along the olfactory nerve to the olfactory bulb. METHODS To determine if olfactory translocation occurs for other solid metal UFPs and assess potential health effects, we exposed groups of rats to mangane...

Key words: in situ stabilization, bioavailable PB, soil remediation This study was conducted to evaluate the effects of P, Mn oxide, and time on bioavailable Pb in five metal-contaminated soils or mine spoils in the absence or the presence of plants, and to evaluate the effect of those treatments on phytoavailability of Pb, Cd, and Zn. The addition of P or Mn oxide reduced bioavailable Pb compa...

We tested the hypothesis that the mitochondrial form of superoxide dismutase [manganese superoxide dismutase (Mn-SOD)] protects the cerebral vasculature. Basilar arteries (baseline diameter approximately 140 microm) from mice were isolated, cannulated, and pressurized to measure vessel diameter. In arteries from C57BL/6 mice preconstricted with U-46619, acetylcholine (ACh; an endothelium-depend...