Transition metals conservative type

Owing to their low reactivity, conservative type transition metals and heavy metals (V, Mo, W, Re, and Tl) are present in sea water at relatively high concentrations that are in constant proportion to salinity. Conservative metals have long mean oceanic residence times ( 10 y), their distributions are considerably homogeneous throughout the ocean due to the ocean s 1000-year circulation, and their concentrations are controlled by physical processes (e.g., advection and turbulent mixing). 

Aldolases are a class of lyases that catalyze the reversible, stereoselective addition of an aldol donor component (nucleophile) to an acceptor component (electrophile) [9,75-81]. Typical products are 3-hydroxy ketones, a structural element that is frequendy incorporated in the framework of complex natural products. Mechanistically, aldolases promote the abstraction of the aldol donor a-proton, thereby generating a carbon nucleophile bound at the active site. In type I aldolases, an enamine is produced by covalent binding to a conserved lysine residue while in the type 11 aldolases, an enediol is formed by chelating coordination to an essential transition metal cation (mostly Zn +), which is acting as a Lewis acid promotor. Aldolases are often highly selective for the donor substrate, tolerating... 

The most common type of source for Fe Mossbauer spectroscopy consists of elemental Co incorporated into a host metal lattice such as rhodium or copper. In the case of Sn measurements, " Sn-enriched CaSnOa or BaSnOa is used as a source. Schematic diagrams of the radioactive decay schemes for these two isotopes are shown in Figure 5. In addition to these transitions, internal conversion processes may give rise to emission of radiation of other energies. For example, in the case of Fe, the / = state may decay via the ejection of a X-shell 7.3-keV electron, and the hole created be filled by an L-shell electron, leading to the emission of either a 6.4-keV electron (Auger process) or X-ray in order to conserve energy. 

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