large reserves of coal in tabas region of iran are characterized by low ash and high caking index, suitable for use in metallurgy as coking coal. however, these coals cannot be gainfully utilized because of their high sulfur content. in this work, studies on desulfurization of tabas coals were carried out in a batch reactor using various reagents. the most effective reagents, fe2(so4)3 , fecl3 ...

Duodenal Fe2+ uptake is essential to body Fe2+ homeostasis, but the interaction of metals with the uptake process remains unclear. The present study compared the effects of four essential trace metals (Mn2+, Zn2+, Co2+ and Ni2+) with two toxic metals (Pb2+ and Cd2+) on Fe2+ uptake across the brush border membrane of villus-attached duodenal enterocytes. Everted rat duodenum was exposed to buffe...

Phosphoenolpyruvate carboxykinase from rat liver cytosol is activated by Fe2+ ions in either direction of catalysis. Preincubation of the purified enzyme with Fe2+ ions causes a time-dependent irreversible loss of activity; this is not seen with unpurified enzyme. Purified enzyme can be protected from inactivation by Fe2+ ions by partially purified protein fractions from liver (ferroactivator f...

Life originated in an anoxic, Fe2+-rich environment. We hypothesize that on early Earth, Fe2+ was a ubiquitous cofactor for nucleic acids, with roles in RNA folding and catalysis as well as in processing of nucleic acids by protein enzymes. In this model, Mg2+ replaced Fe2+ as the primary cofactor for nucleic acids in parallel with known metal substitutions of metalloproteins, driven by the Gre...

Pressure-induced structural changes in di-iron nonacarbonyl [Fe2(CO)9] were examined by in situ Raman spectroscopy with the aid of a diamond anvil cell. Our results indicate that Fe2(CO)9 undergoes a pressure-induced phase transformation at about 0.9 GPa. Upon further compression, another structural transformation is identified at 7 GPa. In the low-pressure phase below 0.9 GPa, the π back-bondi...

Lignocellulosic biomass is a cheap raw material that, thanks to its high carbohydrate content, can be used in fermentation produce biofuels, biogas and other compounds. Its complex structure, including cellulose, hemicellulose lignin, requires prior treatment of the facilitate hydrolysis simple sugars. Today, only partially utilized generates about 14% world's energy. This because most commonly...

I n this issue of PNAS, Chen et al. (1) show that i.p. injection of ‘‘pharmacologic doses’’ of vitamin C decreases the growth and weight of human, rat, and murine tumor xenografts in athymic, nude mice. This work follows a number of articles by the same group, led by Mark Levine at the National Institute of Diabetes and Digestive and Kidney Diseases, showing that millimolar concentrations of ex...

It has already been reported that muscle necrosis induced by various phenylenediamine derivatives are correlated with their autoxidation rate. Now in a more detailed investigation of the cytotoxic mechanism using a model system of isolated hepatocytes and ring-methylated structural isomer durenediamine (DD) we have shown that under aerobic conditions, phenylenediamine induced cytotoxicity and R...