Formation, rouleaux

The hematopoietic system is affected by both short- and long-term arsenic exposure. Arsenic is known to cause a wide variety of hematological abnormalities like anemia, absolute neutropenia, leucopenia, thrombocytopenia, and relative eosinophilia - more common than absolute esino-philia, basophilic stippling, increased bone marrow vascularity, and rouleau formation (Rezuke et al, 1991). These effects may be due to a direct hemolytic or cytotoxic effect on the blood cells and a suppression of erythropoiesis. The mechanism of hemolysis involves depletion of intracellular GSH, resulting in the oxidation of hemoglobin (Saha et al, 1999). Arsenic exposure is also known to influence the activity of several enzymes of heme biosynthesis. Arsenic produces a decrease in ferrochelatase, and decrease in COPRO-OX and increase in hepatic 5-aminolevulinic acid synthetase activity (Woods and Southern, 1989). Subchronic... 

Kinetics of oxidation of isobutene to methacrolein have been studied by Popova and Mil man 103) in a conventional flow reactor. The rates were found to be first order in oxygen and zero order in olefin for formation of both methacrolein and COg. The same orders were reported by Mann and Rouleau lOi) for the over-all oxidation in a static system. Mann and Rouleau 104a) also published data on the kinetics of oxidation of isobutene to methacrolein and COg over a copper oxide on pumice catalyst in a flow system. Selectivities up to about 50 % were observed at C4H8/Og = 0.25-4 and 350-450°. The rate of isobutene oxidation was correlated by the equation... 

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