Total Mn concentration

The map of total Mn concentrations obtained by Synchrotron XRF is presented in Fig. 4(a). Relative concentrations are presented with lighter colours indicating higher metal concentrations. As for TOF-SIMS, there is clearly a higher relative content of Mn at the soil-root interface. Similar results were also obtained for other metals (e.g. Cu and Fe) (Naftel et al, 2002). 

Profiles of total Mn concentrations indicate that the high Mn content in the settling material must be reduced within months. The Mn concentration in the top 5 mm of the sediment was only about 20% of the average Mn content of settling particles at depths of 81 m. Within 2 years the Mn con- 

In Fig. 5 we have gathered the experimental data on the total Mn concentration in the form of a first-order plot. The experiments carried out in the presence of silica (U30, U31 and U34) give rise to a linear relationship in Fig. 5, which supports the idea that the overall precipitation process in the presence of silica can be described by first-order kinetics. For experiment U33 (no carrier), too, a linear plot is obtained, but we hesitate to conclude from this that the precipitation kinetics are first-order in this case. This hesitation arises from (i) the low levels of manganese conversion attained in experiment U33, and (il) the linear relationship obtained in Fig. 4 for this experiment, which suggests zero-order kinetics. 

Adsorption Experiments. The adsorption experiments were performed at 25 0.2 C in 0.1 M NaClO. Mn adsorption experiments were performed under a nitrogen atmosphere at a total Mn(II) concentration of 50pM. Filterable concentrations were determined by analyzing 0.22 micron (Mi 11 ipore Type GWSP) filtered samples. The first 5 mL of the filtrate was discarded. Adsorbed concentrations were determined by difference (i.e. adsorbed = total- filterable). 

From these characterizations, a picture of the Pd-Mn samples can be given. They are made up of both alloy particles, the size of which is about 5 nm and of small MnOx particles (s 1 nm) on the silica support. The Mn content in the bulk of the alloy particles depends on the total Mn concentration in the material and significant segregation of Mn occurs on the outermost layer of the bimetallic particles. 

Vertical profiles of O2 and particulate and dissolved trace metal concentrations at 32.5°E and 44.5°N in the Black Sea. (a) Temperature, salinity, fluorescence, and O2 (b) ammonium, silica, nitrate+nitrite, and phosphate (c) Fe (d) Mn (e) Co (f) Pb (g) Cu (h) Zn (I) Cd and Ni. In the trace metal profiles, the dissolved concentrations are represented as solid circles, the total particulate concentrations by open circles, the acid-leachable particulate concentrations by open squares, and the suspended particulate matter concentrations by the solid triangles. Source-. After Tankere, S. P. C., et al. (2001). Continental Shelf Research, 21, 1501-1532. 

Manganese is found in much higher concentrations in infant formulas than in breast milk. In fact, soy-based formulas were shown to contain about 80 times more Mn than breast milk [11]. Also, animal protein-based formulas contained also about 30 times more Mn than human milk. Infants are not able to absorb and excrete excess Mn during their first year of life, a period of rapid development. As Mn is neurotoxic and impairs intestinal Fe absorption, it would be desirable to reduce Mn levels in infant formulas down to those found in human milk (4-8 p,g l-1). Coni et al. [12] reported that in formulas more than 25 percent of total Mn is bound to caseins. On the other hand, Mn present in soy- and in cow s milk-based formula whey is mainly associated with LMW components (< 10 kDa), as is the case with human milk whey [15, 18, 34, 72], 

Kase and Horiuchi (1996) obtained a large number of analytical data on sphalerites from sixteen Besshi-type deposits, mainly at Besshi and its vicinity, Hitachi, and Shimokawa. They revealed that (1) the Mn/Zn and Co/Zn ratios of sphalerite may have markedly increased during contact metamorphism, while the Cd/Zn ratios remained unchanged (2) the Emco/ lwzn (2/n total dissolved concentration in ore fluids) and Emco/S/wzn ratios in the initial ore solutions responsible for the mineralizations at Besshi which was calculated ba.sed on the equilibrium fractionation model between hydrothermal solution and sphalerite and analytical data on sphalerites are quite similar to the ratios of hydrothermal solutions at EPR 21 °N (3) however, these ratios for the Hitachi solutions are very low and different from those of the Besshi-subtype solution. 

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