A colorimetric carbonate procedure for the determination of uric acid has been modified to include incubation of serum with uricase to destroy uric acid. Residual nonurate chromogens are subtracted from total chromogens to obtain the concentration of “true” uric acid. Result obtained by the carbonate and the uricase-carbonate methods were in good agreement. The mean concentration of nonurate ch...

This work has been undertaken in order to obtain data on thermodynamic properties of organic carbonates and to revise the group-additivity values necessary for predicting their standard enthalpies of formation and enthalpies of vaporization. The standard molar enthalpies of formation of dibenzyl carbonate, tert-butyl phenyl carbonate, and diphenyl carbonate were measured using combustion calori...

in this research, kinetics of carbothermic reduction of molybdenite in the presence of different amounts of sodium carbonate has been studied. mixed powders consisting of molybdenite, graphite and sodium carbonate with three mole-ratios of 1:4:2,1:4:3 and 1:4:4 were mechanically activated for 40 hours. the results of x-ray diffraction on activated samples showed that no reaction occurrs in diff...

in this study, vanadium recovery from the steelmaking converter slag was studied. salt roasting-basic leaching is the process which was applied to separate and extract vanadium from steel making slag. ground slag was roasted after mixing with determined quantities of sodium carbonate. the effect of time and temperature of roasting and sodium carbonate content were studied. the optimum temperatu...

[1] It has been suggested that the incorporation of strontium into biogenic aragonite may be influenced by the degree of carbonate saturation in aquatic environments. We measured the Sr/Ca ratios of river water and the aragonitic shells of freshwater bivalves (Margaritifera margaritifera) from two sites with different carbonate saturation states in the River Ehen, Cumbria, UK. Shell Sr/Ca and r...

Stable carbon isotope analysis of fossil tooth enamel carbonate, and oxygen isotope analysis of bone or enamel phosphate, are established tools for palaeodietary and palaeoclimatic reconstruction, respectively. C/C ratios provide evidence of an animal’s diet and phosphate-based O/O values are used to establish palaeotemperature proxies. Recent studies of fossil enamel suggest that biogenic O/O ...

In the last few years, evidence has accumulated that calcifying organisms are likely to be affected by ocean acidification. Therefore, the production of calcium carbonate will probably decline, although conversely global warming, increasing stratification and sea level rise may also stimulate increases in global calcification. As acidification reaches the deep ocean, it will cause pronounced sh...

Although phosphate and carbonate are important constituents in ancient and modern environments, it is not yet clear their biogeochemical relationships and their mechanisms of formation. Microbially mediated carbonate formation has been widely studied whereas little is known about the formation of phosphate minerals. Here we report that a new bacterial strain, Tessarococcus lapidicaptus, isolate...

We study liquid diphenyl carbonate (DPC) with molecular dynamics simulations in the temperature range from 350 to 600 K. The diiusion behavior as well as structural and relaxation properties of this complex liquid are analyzed in detail. To this end, an all-atom force eld is developed for DPC. We studied two sets of partial charges and the innuence of the torsion barrier at the carbonate group....

A solution-phase route has been considered as the most promising route to synthesize noble nanostructures. A majority of their synthesis approaches of calcium carbonate (CaCO3) are based on either using fungi or the CO2 bubbling methods. Here, we approached the preparation of nano-precipitated calcium carbonate single crystal from salmacis sphaeroides in the presence of zwitterionic or cationic...