Ethyl acetoacetate modi®ed aluminium sec-butoxide can be hydrolysed and gelled with alkaline, neutral or acidic media within a pH range of 3.0±8.5. Alumina precipitation occurs if pH values at any point in the sol±gel transition are outside this range. Nine di€erent gelling agents have been evaluated for pH dependence of gel point. Based on stoichiometric considerations, only those systems with...

in this study, nf membrane was used for surface water treatment. the rejection of organic material, measured as total organic carbon (toc), by nanofiltration was examined. the effects of application of pre-ozonation and pre-chlorination on toc removal are discussed and their performances are compared with the performances of nanofiltraion system without pretreatment process. in nf, natural orga...

Aminoacylase (EC 3.5.1.14) from Aspergillus oryzae was purified from a commercially available crude material by heat treatment, precipitation by polyethyleneimine and ammoniumsulfate, gel chromatography and preparative disc-gel-electrophoresis. The purified product was homogenous as judged by polyacrylamide gel electrophoresis. SDS-gel electrophoresis, polyacrylamide-gel-gradient electrohoresis...

enzymes. Necessary requirements include: (i) the enzyme must contain more than one ligand binding site; (ii) the bis-ligand should have strong affinity for the enzyme; (iii) the spacer connecting the two ligand entities should have sufficient length to cover the distance between two ligand binding sites situated on different molecules. AfRnity precipitation has been applied to several dehydroge...

Otoliths are calcium carbonate concretions laid down in the inner ear of fish and used in fish age estimation. Otoliths precipitate in the form of aragonite but aberrant precipitation may result in vaterite formation instead of aragonite. Vaterite otoliths are more translucent than aragonite. The quantity of HCl-soluble proteins (SP) was measured in the vaterite otoliths and their aragonite pai...

In this study, SiO2 nanoparticles were successfully synthesized via sol-gel precipitation method and the effects of different parameters such as temperature, ethanol, ammonia and tetraethylorthosilicate (TEOS) contents based on water were investigated in a systematic way applying Taguchi experimental design method. It was found that, among all the investigated parameters, ethanol as a co-solven...

The diversity of microbial communities constitutes a critical component of good soil-management practices. To characterize the effects of different management practices, molecular indicators such as phospholipid fatty acid (PLFA), denaturing gradient gel electrophoresis (DGGE) and composition of ammonia-oxidizing bacteria were used to analyze bacterial community structure and diversity from fou...

Estrogen binding protein activities were determined in the cytosol from adult male Buffalo rat liver and Morris hepatoma 7777. Estrogen receptors were prepared using the protamine sulfate precipitation technique of Chamness. The ability of various unlabeled steroids competing with [3H]estradiol was examined to establish the binding specificity. Estradiol binding in Morris hepatoma 7777 cytosol ...

Hummel’s (1) fluorometric determination of malic acid requires the precipitation of calcium malate by alcohol as a means of fractionation from biological materials. Fructose-l, 6-diphosphate, glucose-6-phosphate, or glycogen if present must be removed. Below is described a method for preparing extracts of tissues which applies the principles of chromatography on silica gel. Osazone formation, p...

Electropolishing of metals often leads to supersaturation conditions resulting in precipitation of complex compounds. The solubility diagrams and Gibbs adsorption isotherms of the electropolishing products are thus very important to understand the thermodynamic mechanism of precipitation of reaction products. Electropolishing of tungsten wires in aqueous solutions of potassium hydroxide is used...