Increased oxidation state

The cellular oxidation state is increased rapidly yet transiently by events associated with binding to the hemopexin receptor and hemopexin-mediated heme transport. High concentrations of heme-hemopexin raise the cell carbonyl content to approximately 7nmolmg protein which is equivalent to the level produced in response to 400pM H2O2 within 15 minutes. This oxidation is dose-dependent from 2-lOpM heme-hemopexin and declines after 30 minutes, presmnably due to rapid degradation since oxidized proteins are susceptible to proteolysis [118]. CoPP-hemopexin complexes which effectively bind to the hemopexin receptor but without tetrapyrrole uptake [42], do not increase carbonyl levels whereas free heme (2-10 jiM) does and to levels similar to those seen with heme-hemopexin. 

when intracellular levels of heme rise to a certain level, either by diffusion of free heme or from hemopexin-mediated transport, oxidation of proteins takes place. Free heme reportedly does not diminish GSH levels [119]. Thus, it would appear that a redox-active metal is involved. These cells are replete in ferritin and ferritin is induced as iron is released from heme catabolism. The form of metal, likely to be either Fe /Fe , Cu +/Cu +, Fe +-heme/Fe +-heme, is currently unknown as are the molecular sites of oxidation. Studies with ferrous and ferric che- 

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Increasing oxidation state of carbon (decreasing hydrogen content)... 

Since n bonding is believed to be more important in low oxidation states, as d orbitals contract with increasing oxidation state leading to poorer dw-pw overlap, this would not be expected on the basis of a 7r-bonding mechanism. Similarly, one can compare /(Pt-P) for pairs of isomers in the +2 and +4 states in a planar platinum(II) complex, the platinum 6s orbital is shared by four ligands whereas in an octahedral platinum(IV) complex it is shared by six ligands. Therefore, the 6s character is expected to be only 2/3 as much in the platinum(IV) complexes, correlating well with the 7(Pt-P) values, which can be taken to be a measure of the a-character in the bond. 

Electroviscous effect occurs when a small addition of electrolyte a colloid produces a notable decrease in viscosity. Experiments with different salts have shown that the effective ion is opposite to that of the colloid particles and the influence is much greater with increasing oxidation state of the ion. That is, the decrease in viscosity is associated with decreased potential electrokinetic double layer. The small amoimt of added electrolyte can not appreciably affect on the solvation of the particles, and thus it is possible that one of the determinants of viscosity than the actual volume of the dispersed phase is the zeta potential. 

The acidity and the covalent nature of transition metal oxides generally increases with increasing oxidation state of the metals. This is shown by the oxides of chromium. 

Lanthanide fluoride sequences show monotonic increase in bond energy with increasing oxidation state, although one would expect a maximum for EuF2 in the europium series at the stable f7 configuration. 

Experiments over Cu/ZSM-5, Centi and Perathoner[46] eoncluded that the thermal stability of adsorbed species increased with increasing oxidation state of nitrogen in nitrogen adspeeies. Valyon and Hall[41] also found that the nitrosyl speeies adsorbed on Co-ferrierite is weakly adsorbed compared to nitrate species. Therefore, the second NO desorption peak oeeurring at medium temperatures likely corresponds to the nitrosyl species, according to their thermal stability. 

As a general rule the c.t. bands shift to lower energies with increasing oxidation state, whereas Rydberg transitions (such as 4f- -5d transitions) shift to higher energies. It may, therefore, be expected that the lowest absorption bands of the tetravalent lanthanide ions will be due c. t. transitions and those of the divalent lanthanide ions to Af- -5d transitions. 

A hypsochromic shift was observed for the benzo-bis-l,3,2-dithiazole system (Section 4.12.4.6) with increasing oxidation state from diradical (62) through radical cation (61) to dication (60) 560, 504, and 450 nm <86SM239>. 

An interesting by-product of the new values (3) is that a does not decrease so rapidly with increasing oxidation state in chemical species... 

A good variety of compounds have been prepared and characterized allowing us to obtain reliable information on the chemical shifts of saturated and unsaturated ring protons. A selection of different structures are shown in Table 4. The thiazine derivatives have been organized in groups for comparison. The effects of saturation (54, 105, 106), substituents of variable electronegativity (107, 108), increasing oxidation state of sulfur (121, 122, 27-29), and deprotonation (109-111) can be observed. 

The stability of the (M6Xi2),+ compounds towards hydrolysis decreases in the order Ta>Nb, Cl>Br, and with increasing oxidation states. Evidence has been reported for partial replacement of the chlorines by hydroxo groups in [Nb6CI, 5] -7H20.672... 

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