The ultra-fine magnesium oxide powders were obtained via direct precipitation process, during which the industrial pure MgSO4·7H2O( origined from szaibelyite) and (NH4)2C2O4 were emplyed as raw materials. The precursor and the final product Nano-meter MgO powders were characterized by IR, XRD and TEM. It belongs to cubic lattic, in sphere shape, white, stable in air. The diameter of powder is about 25-35 nm and homogenous. The mechanism and factors that influences the quality of final produce, such as reaction concentration, feeding fashion, calcining temperature were investigated.

Interaction of 8-Acetyl-7-hydroxycoumarin with human serum albumin (HSA) at pH 7.40 has been investigated at 291, 301 and 310 K, respectively, employing the steady fluorescence, circular dichroism (CD) and molecular modeling methods. The quenching mechanism and binding constants were determined by the fluorescence quenching experiments. Thermodynamic data showed that 8-Acetyl-7-hydroxycoumarin was included in the hydrophobic cavity of HSA via hydrophobic interactions. The result of CD indicated that the binding of 8-Acetyl-7-hydroxycoumarin to HSA causes a slight conformational change of the protein. Furthermore, upon binding with HSA, the fluorescence spectra of the 8-Acetyl-7-hydroxycoumarin exhibits appreciable hypsochromic shift associated with an enhancement in the fluorescence intensity. The binding constant (K) and the standard free energy change (DeltaG0) have been also calculated according to the fluorescence data of the ligand, which is in good agreement with the values determined by fluorescence quenching data of HSA. Computational mapping of the possible binding sites of 8-Acetyl-7-hydroxycoumarin revealed that the molecule was bound in the large hydrophobic cavity of subdomain IIA mainly by the hydrophobic interaction and also by the hydrogen bonding interactions between 8-Acetyl-7-hydroxycoumarin and the residues His 242, Arg 222, and Arg 218.