Search results for "Manga"
showing 10 items of 743 documents
Assessment of Dietary Intake of Manganese in Relation to Tolerable Upper Intake Level
2019
The Norwegian Scientific Committee for Food and Environment (Vitenskapskomiteen for mat og miljø, VKM) has, at the request of the Norwegian Food Safety Authority (Mattilsynet; NFSA), evaluated the intake of manganese from the diet and 1, 5 or 10 mg manganese per day in food supplements. The former maximum limit for manganese in food supplements was 5 mg per daily dose. 
 Manganese (Mn) is an essential dietary mineral for mammals, and is a component of metalloenzymes such as superoxide dismutase, arginase and pyruvate carboxylase. Manganese is involved in amino acid-, lipid- and carbohydrate metabolism and in proteoglycan synthesis in bone formation. In 2013, the European Food Safety Au…
Micro magnetofluidics: droplet manipulation of double emulsions based on paramagnetic ionic liquids
2013
The ability to control and manipulate discrete fluid droplets by magnetic fields offers new opportunities in microfluidics. A surfactant-free and easy to realize technique for the continuous generation of double emulsion droplets, composed of an organic solvent and a paramagnetic ionic liquid, is applied. The inner phase of the emulsion droplet consists of imidazolium-based ionic liquids with either iron, manganese, nickel or dysprosium containing anions which provide paramagnetic behaviour. The double emulsion droplets are dispersed in a continuous phase of FC-40. All substances - the organic phase, the paramagnetic ionic liquid and the continuous phase -are immiscible. The magnetic proper…
Electrochemistry and spectroelectrochemistry of bismanganese biscorroles dyads
2011
Three manganese biscorrole dyads were synthesized, physicochemically characterized and investigated as to their electrochemistry and spectroelectrochemistry in nonaqueous media. Each dyad contained the same two corroles linked in a face-to-face arrangement via one of the three different linking groups, 9,9-dimethylxanthene, anthracene or diphenylether, the exact nature of which determined the distance and possible interaction between the two metallomacrocycles. The initial compounds contained Mn ( III ) in their air stable form and were shown to exhibit two major redox processes, one being a Mn (III)/ Mn (IV) conversion and the other being either Mn ( III )/ Mn ( II ) or reduction at the c…
Oxidative stress protection by manganese complexes of tail-tied aza-scorpiand ligands.
2015
The Mn2+ coordination chemistry of double scorpiand ligands in which two polyazacyclophane macrocycles have been connected by pyridine, phenanthroline and bipyridine spacers has been studied by potentiometry, paramagnetic NMR and electrochemistry. All ligands show high stability with Mn2+ and the complexes were formed in a wide pH range. DFT calculations support the structures and coordination geometries derived from the study. A remarkable antioxidant activity was evidenced for these systems by the McCord-Fridovich assay and in Escherichiacoli sodAsodB deficient bacterial cells. The three systems were tested as anti-inflammatory drugs in human macrophages measuring the accumulation of cyto…
[Mnii2(bpym)(H2O)8]4+ and [Miv(CN)8]4– (M = Mo and W) as building blocks in designing bpym- and cyanide-bridged bimetallic three-dimensional networks…
2002
One-pot reaction between the dinuclear [MnII2(bpym)(H2O)8]4+ complex and the mononuclear [MIV(CN)8]4− unit (M = Mo and W; bpym = 2,2′-bipyrimidine) in aqueous solution yields the novel heterobimetallic complexes of formula {(μ-bpym)[Mn(H2O)]2-(μ-NC)6M(CN)2} with M = Mo (1) and W (2). 1 and 2 are isostructural three-dimensional compounds where the manganese atoms are bridged by bisbidentate bpym and hexakismonodentate octacyanometalate units. Variable-temperature magnetic susceptibility data of 1 and 2 show the occurrence of a significant antiferromagnetic coupling between the high spin manganese(II) ions through bridging bpym (Jca. −1.1 cm−1, the exchange Hamiltonian being defined as H = −J…
Thermodynamic parameters for the formation of glycine complexes with magnesium(II), calcium(II), lead(II), manganese(II), cobalt(II), nickel(II), zin…
1995
Abstract Protonation constants and Mg 2+ , Ca 2+ , Pb 2+ , Mn 2+ -, Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ and Cd 2+ glycine complex formation constants have been determined in different aqueous media at different temperatures. Salt effects are explained by a complex formation model which takes into account the formation of weak species. From the temperature dependence of the formation constants, thermodynamic parameters ΔH θ (and in some cases ΔC θ p ) have been obtained. A rigorous analysis of literature data, together with experimental findings, allows recommended formation parameters, in the ranges 0 ≤ I e ≤ 1 mol l −1 ( I e is the effective ionic strength) and 5°C ≤ T ≤ 45°C, to be obt…
Kinetics of the permanganate oxidation of formic acid in aqueous solution
1987
The kinetics of the permanganate oxidation of formic acid in aqueous perchloric acid at 30°C were examined by the spectrophotometric method. The chemical reaction 2MnO + 3HCOOH + 2H+ 2MnO2 + 3CO2 + 4H2O, appears to proceed via several parallel reactions. The overall rate equation has been obtained by using statistical multilinear regression analysis of the 660 cases studied, and the presence in the rate equation of two new terms in relation to previous studies shows that both permanganate autocatalytic effects and acid media inhibition must be taken into account when the reaction proceeds at constant ionic strength.
Screening the bulk properties and reducibility of Fe-doped Mn2O3 from first principles calculations
2017
Abstract Manganese oxides, particularly Mn 2 O 3 , have demonstrated great potential for oxygen carrier materials in chemical looping applications. The application of these materials in the industrial scale is hindered by thermodynamic restrictions related to the reoxidation process. This disadvantage can be overcome by doping the oxide with a guest cation. Iron is one of the most promising dopants, but the atomic-level understanding of its effects on the properties of α-Mn 2 O 3 is incomplete. Herein, we report a systematic GGA+U study of the bulk properties and reducibility of Fe x Mn 2-x O 3 (0 ≤ x ≤ 2) as a function of Fe dopant concentration. In particular, we focus on a representative…
Manganese(II) complexes of scorpiand-like azamacrocycles as MnSOD mimics.
2011
Mn(II) complexes of scorpiand-type azamacrocycles constituted by a tretrazapyridinophane core appended with an ethylamino tail including 2- or 4-quinoline functionalities show very appealing in vitro SOD activity. The observed behaviour is related to structural and electrochemical parameters.
XAFS Studies of High-Valent Porphyrinato Manganèse Complexes with Ozone
1997
We produce strong evidence of the interaction of ozone with a series of Manganese (III) porphyrinato complexes to form a well defined reactive intermediate. In the latter species, the Manganese atom which is formally in a tetravalent (IV) state, is (at least) hexacoordinated with the metal unambiguously lying in the basal plane of the four pyrrolic nitrogens of the porphyrin macrocycle. Substitution of Bromine or Chlorine axial ligands by ozonids is most likely to happen. This conclusion is also supported by XANES and EXAFS spectra recorded at the Chlorine K-edge which suggest that ozone may even form with chlorine a complex anion.