The effect of midazolam sedation on baseline fMRI signal

A process for producing a filler for upgrading drilling fluid, especially for supporting the strata of deep drill holes or bores of the type used for oil and subsurface exploration, comprises the steps of comminuting a sulfur-containing iron mineral which is roasted to a sulfur content of less than 2 percent by weight, neutralizing the comminuted product upon dispersion thereof in water, leaching soluble components from the material and drying the same. The oxidic roasted product is classified to a particle size below 75 microns and a particle size distribution such that no more than 50 percent (preferably less than 30 percent) is below a particle size of 10 microns. Preferably, the composition is classified in the following particle size distribution: 50-55 percent of a particle size between 30 and 75 microns, 10-15 percent of a particle size between 20 and 30 microns, 10-15 percent between 10 and 20 microns, and 20-30 percent in a particle size up to 10 microns.